linux/Makefile

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License cleanup: add SPDX GPL-2.0 license identifier to files with no license Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-01 14:07:57 +00:00
# SPDX-License-Identifier: GPL-2.0
2022-08-14 22:50:18 +00:00
VERSION = 6
2024-05-26 22:20:12 +00:00
PATCHLEVEL = 10
SUBLEVEL = 0
2024-06-30 21:40:44 +00:00
EXTRAVERSION = -rc6
2024-05-26 22:20:12 +00:00
NAME = Baby Opossum Posse
# *DOCUMENTATION*
# To see a list of typical targets execute "make help"
# More info can be located in ./README
# Comments in this file are targeted only to the developer, do not
# expect to learn how to build the kernel reading this file.
ifeq ($(filter undefine,$(.FEATURES)),)
$(error GNU Make >= 3.82 is required. Your Make version is $(MAKE_VERSION))
endif
$(if $(filter __%, $(MAKECMDGOALS)), \
$(error targets prefixed with '__' are only for internal use))
# That's our default target when none is given on the command line
PHONY := __all
__all:
# We are using a recursive build, so we need to do a little thinking
# to get the ordering right.
#
# Most importantly: sub-Makefiles should only ever modify files in
# their own directory. If in some directory we have a dependency on
# a file in another dir (which doesn't happen often, but it's often
# unavoidable when linking the built-in.a targets which finally
# turn into vmlinux), we will call a sub make in that other dir, and
# after that we are sure that everything which is in that other dir
# is now up to date.
#
# The only cases where we need to modify files which have global
# effects are thus separated out and done before the recursive
# descending is started. They are now explicitly listed as the
# prepare rule.
this-makefile := $(lastword $(MAKEFILE_LIST))
abs_srctree := $(realpath $(dir $(this-makefile)))
abs_objtree := $(CURDIR)
ifneq ($(sub_make_done),1)
kbuild: make -r/-R effective in top Makefile for old Make versions Adding -rR to MAKEFLAGS is important because we do not want to be bothered by built-in implicit rules or variables. One problem that used to exist in older GNU Make versions is MAKEFLAGS += -rR ... does not become effective in the current Makefile. When you are building with O= option, it becomes effective in the top Makefile since it recurses via 'sub-make' target. Otherwise, the top Makefile tries implicit rules. That is why we explicitly add empty rules for Makefiles, but we often miss to do that. In fact, adding -d option to older GNU Make versions shows it is trying a bunch of implicit pattern rules. Considering target file `scripts/Makefile.kcov'. Looking for an implicit rule for `scripts/Makefile.kcov'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.o'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.c'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.cc'. Trying pattern rule with stem `Makefile.kcov'. Trying implicit prerequisite `scripts/Makefile.kcov.C'. ... This issue was fixed by GNU Make commit 58dae243526b ("[Savannah #20501] Handle adding -r/-R to MAKEFLAGS in the makefile"). So, it is no longer a problem if you use GNU Make 4.0 or later. However, older versions are still widely used. So, I decided to patch the kernel Makefile to invoke sub-make regardless of O= option. This will allow further cleanups. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-02-22 07:40:07 +00:00
# Do not use make's built-in rules and variables
# (this increases performance and avoids hard-to-debug behaviour)
MAKEFLAGS += -rR
# Avoid funny character set dependencies
unexport LC_ALL
LC_COLLATE=C
LC_NUMERIC=C
export LC_COLLATE LC_NUMERIC
# Avoid interference with shell env settings
unexport GREP_OPTIONS
# Beautify output
# ---------------------------------------------------------------------------
#
# Most of build commands in Kbuild start with "cmd_". You can optionally define
# "quiet_cmd_*". If defined, the short log is printed. Otherwise, no log from
# that command is printed by default.
#
# e.g.)
# quiet_cmd_depmod = DEPMOD $(MODLIB)
# cmd_depmod = $(srctree)/scripts/depmod.sh $(DEPMOD) $(KERNELRELEASE)
#
# A simple variant is to prefix commands with $(Q) - that's useful
# for commands that shall be hidden in non-verbose mode.
#
# $(Q)$(MAKE) $(build)=scripts/basic
#
# If KBUILD_VERBOSE contains 1, the whole command is echoed.
# If KBUILD_VERBOSE contains 2, the reason for rebuilding is printed.
#
# To put more focus on warnings, be less verbose as default
# Use 'make V=1' to see the full commands
ifeq ("$(origin V)", "command line")
KBUILD_VERBOSE = $(V)
endif
quiet = quiet_
Q = @
ifneq ($(findstring 1, $(KBUILD_VERBOSE)),)
quiet =
Q =
endif
# If the user is running make -s (silent mode), suppress echoing of
# commands
# make-4.0 (and later) keep single letter options in the 1st word of MAKEFLAGS.
ifeq ($(filter 3.%,$(MAKE_VERSION)),)
short-opts := $(firstword -$(MAKEFLAGS))
else
short-opts := $(filter-out --%,$(MAKEFLAGS))
endif
ifneq ($(findstring s,$(short-opts)),)
quiet=silent_
override KBUILD_VERBOSE :=
endif
export quiet Q KBUILD_VERBOSE
# Call a source code checker (by default, "sparse") as part of the
# C compilation.
#
# Use 'make C=1' to enable checking of only re-compiled files.
# Use 'make C=2' to enable checking of *all* source files, regardless
# of whether they are re-compiled or not.
#
# See the file "Documentation/dev-tools/sparse.rst" for more details,
# including where to get the "sparse" utility.
ifeq ("$(origin C)", "command line")
KBUILD_CHECKSRC = $(C)
endif
ifndef KBUILD_CHECKSRC
KBUILD_CHECKSRC = 0
endif
export KBUILD_CHECKSRC
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# Enable "clippy" (a linter) as part of the Rust compilation.
#
# Use 'make CLIPPY=1' to enable it.
ifeq ("$(origin CLIPPY)", "command line")
KBUILD_CLIPPY := $(CLIPPY)
endif
export KBUILD_CLIPPY
# Use make M=dir or set the environment variable KBUILD_EXTMOD to specify the
# directory of external module to build. Setting M= takes precedence.
ifeq ("$(origin M)", "command line")
KBUILD_EXTMOD := $(M)
endif
$(if $(word 2, $(KBUILD_EXTMOD)), \
$(error building multiple external modules is not supported))
$(foreach x, % :, $(if $(findstring $x, $(KBUILD_EXTMOD)), \
$(error module directory path cannot contain '$x')))
# Remove trailing slashes
ifneq ($(filter %/, $(KBUILD_EXTMOD)),)
KBUILD_EXTMOD := $(shell dirname $(KBUILD_EXTMOD).)
endif
export KBUILD_EXTMOD
# backward compatibility
KBUILD_EXTRA_WARN ?= $(KBUILD_ENABLE_EXTRA_GCC_CHECKS)
ifeq ("$(origin W)", "command line")
KBUILD_EXTRA_WARN := $(W)
endif
export KBUILD_EXTRA_WARN
# Kbuild will save output files in the current working directory.
# This does not need to match to the root of the kernel source tree.
#
# For example, you can do this:
#
# cd /dir/to/store/output/files; make -f /dir/to/kernel/source/Makefile
#
# If you want to save output files in a different location, there are
# two syntaxes to specify it.
#
# 1) O=
# Use "make O=dir/to/store/output/files/"
#
# 2) Set KBUILD_OUTPUT
# Set the environment variable KBUILD_OUTPUT to point to the output directory.
# export KBUILD_OUTPUT=dir/to/store/output/files/; make
#
# The O= assignment takes precedence over the KBUILD_OUTPUT environment
# variable.
# Do we want to change the working directory?
ifeq ("$(origin O)", "command line")
KBUILD_OUTPUT := $(O)
endif
ifneq ($(KBUILD_OUTPUT),)
# $(realpath ...) gets empty if the path does not exist. Run 'mkdir -p' first.
$(shell mkdir -p "$(KBUILD_OUTPUT)")
# $(realpath ...) resolves symlinks
abs_objtree := $(realpath $(KBUILD_OUTPUT))
$(if $(abs_objtree),,$(error failed to create output directory "$(KBUILD_OUTPUT)"))
endif # ifneq ($(KBUILD_OUTPUT),)
ifneq ($(words $(subst :, ,$(abs_srctree))), 1)
$(error source directory cannot contain spaces or colons)
endif
ifneq ($(filter 3.%,$(MAKE_VERSION)),)
# 'MAKEFLAGS += -rR' does not immediately become effective for GNU Make 3.x
# We need to invoke sub-make to avoid implicit rules in the top Makefile.
need-sub-make := 1
# Cancel implicit rules for this Makefile.
$(this-makefile): ;
endif
export sub_make_done := 1
kbuild: revive "Entering directory" for Make >= 4.4.1 With commit 9da0763bdd82 ("kbuild: Use relative path when building in a subdir of the source tree"), compiler messages in out-of-tree builds include relative paths, which are relative to the build directory, not the directory where make was started. To help IDEs/editors find the source files, Kbuild lets GNU Make print "Entering directory ..." when it changes the working directory. It has been working fine for a long time, but David reported it is broken with the latest GNU Make. The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537] Fix setting -w in makefiles"). Previously, setting --no-print-directory to MAKEFLAGS only affected child makes, but it is now interpreted in the current make as soon as it is set. [test code] $ cat /tmp/Makefile ifneq ($(SUBMAKE),1) MAKEFLAGS += --no-print-directory all: ; $(MAKE) SUBMAKE=1 else all: ; : endif [before 8f9e7722ff0f] $ make -C /tmp make: Entering directory '/tmp' make SUBMAKE=1 : make: Leaving directory '/tmp' [after 8f9e7722ff0f] $ make -C /tmp make SUBMAKE=1 : Previously, the effect of --no-print-directory was delayed until Kbuild started the directory descending, but it is no longer true with GNU Make 4.4.1. This commit adds one more recursion to cater to GNU Make >= 4.4.1. When Kbuild needs to change the working directory, __submake will be executed twice. __submake without --no-print-directory --> show "Entering directory ..." __submake with --no-print-directory --> parse the rest of Makefile We end up with one more recursion than needed for GNU Make < 4.4.1, but I do not want to complicate the version check. Reported-by: David Howells <dhowells@redhat.com> Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <n.schier@avm.de>
2023-06-26 23:30:13 +00:00
endif # sub_make_done
ifeq ($(abs_objtree),$(CURDIR))
# Suppress "Entering directory ..." if we are at the final work directory.
no-print-directory := --no-print-directory
else
# Recursion to show "Entering directory ..."
need-sub-make := 1
endif
ifeq ($(filter --no-print-directory, $(MAKEFLAGS)),)
# If --no-print-directory is unset, recurse once again to set it.
# You may end up recursing into __sub-make twice. This is needed due to the
# behavior change in GNU Make 4.4.1.
need-sub-make := 1
endif
ifeq ($(need-sub-make),1)
PHONY += $(MAKECMDGOALS) __sub-make
$(filter-out $(this-makefile), $(MAKECMDGOALS)) __all: __sub-make
@:
# Invoke a second make in the output directory, passing relevant variables
__sub-make:
kbuild: revive "Entering directory" for Make >= 4.4.1 With commit 9da0763bdd82 ("kbuild: Use relative path when building in a subdir of the source tree"), compiler messages in out-of-tree builds include relative paths, which are relative to the build directory, not the directory where make was started. To help IDEs/editors find the source files, Kbuild lets GNU Make print "Entering directory ..." when it changes the working directory. It has been working fine for a long time, but David reported it is broken with the latest GNU Make. The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537] Fix setting -w in makefiles"). Previously, setting --no-print-directory to MAKEFLAGS only affected child makes, but it is now interpreted in the current make as soon as it is set. [test code] $ cat /tmp/Makefile ifneq ($(SUBMAKE),1) MAKEFLAGS += --no-print-directory all: ; $(MAKE) SUBMAKE=1 else all: ; : endif [before 8f9e7722ff0f] $ make -C /tmp make: Entering directory '/tmp' make SUBMAKE=1 : make: Leaving directory '/tmp' [after 8f9e7722ff0f] $ make -C /tmp make SUBMAKE=1 : Previously, the effect of --no-print-directory was delayed until Kbuild started the directory descending, but it is no longer true with GNU Make 4.4.1. This commit adds one more recursion to cater to GNU Make >= 4.4.1. When Kbuild needs to change the working directory, __submake will be executed twice. __submake without --no-print-directory --> show "Entering directory ..." __submake with --no-print-directory --> parse the rest of Makefile We end up with one more recursion than needed for GNU Make < 4.4.1, but I do not want to complicate the version check. Reported-by: David Howells <dhowells@redhat.com> Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <n.schier@avm.de>
2023-06-26 23:30:13 +00:00
$(Q)$(MAKE) $(no-print-directory) -C $(abs_objtree) \
-f $(abs_srctree)/Makefile $(MAKECMDGOALS)
kbuild: revive "Entering directory" for Make >= 4.4.1 With commit 9da0763bdd82 ("kbuild: Use relative path when building in a subdir of the source tree"), compiler messages in out-of-tree builds include relative paths, which are relative to the build directory, not the directory where make was started. To help IDEs/editors find the source files, Kbuild lets GNU Make print "Entering directory ..." when it changes the working directory. It has been working fine for a long time, but David reported it is broken with the latest GNU Make. The behavior was changed by GNU Make commit 8f9e7722ff0f ("[SV 63537] Fix setting -w in makefiles"). Previously, setting --no-print-directory to MAKEFLAGS only affected child makes, but it is now interpreted in the current make as soon as it is set. [test code] $ cat /tmp/Makefile ifneq ($(SUBMAKE),1) MAKEFLAGS += --no-print-directory all: ; $(MAKE) SUBMAKE=1 else all: ; : endif [before 8f9e7722ff0f] $ make -C /tmp make: Entering directory '/tmp' make SUBMAKE=1 : make: Leaving directory '/tmp' [after 8f9e7722ff0f] $ make -C /tmp make SUBMAKE=1 : Previously, the effect of --no-print-directory was delayed until Kbuild started the directory descending, but it is no longer true with GNU Make 4.4.1. This commit adds one more recursion to cater to GNU Make >= 4.4.1. When Kbuild needs to change the working directory, __submake will be executed twice. __submake without --no-print-directory --> show "Entering directory ..." __submake with --no-print-directory --> parse the rest of Makefile We end up with one more recursion than needed for GNU Make < 4.4.1, but I do not want to complicate the version check. Reported-by: David Howells <dhowells@redhat.com> Closes: https://lore.kernel.org/all/2427604.1686237298@warthog.procyon.org.uk/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Tested-by: Nicolas Schier <n.schier@avm.de>
2023-06-26 23:30:13 +00:00
else # need-sub-make
# We process the rest of the Makefile if this is the final invocation of make
ifeq ($(abs_srctree),$(abs_objtree))
# building in the source tree
srctree := .
building_out_of_srctree :=
else
ifeq ($(abs_srctree)/,$(dir $(abs_objtree)))
# building in a subdirectory of the source tree
srctree := ..
else
srctree := $(abs_srctree)
endif
building_out_of_srctree := 1
endif
ifneq ($(KBUILD_ABS_SRCTREE),)
srctree := $(abs_srctree)
endif
objtree := .
VPATH :=
ifeq ($(KBUILD_EXTMOD),)
ifdef building_out_of_srctree
VPATH := $(srctree)
endif
endif
export building_out_of_srctree srctree objtree VPATH
# To make sure we do not include .config for any of the *config targets
# catch them early, and hand them over to scripts/kconfig/Makefile
# It is allowed to specify more targets when calling make, including
# mixing *config targets and build targets.
# For example 'make oldconfig all'.
# Detect when mixed targets is specified, and make a second invocation
# of make so .config is not included in this case either (for *config).
version_h := include/generated/uapi/linux/version.h
clean-targets := %clean mrproper cleandocs
no-dot-config-targets := $(clean-targets) \
cscope gtags TAGS tags help% %docs check% coccicheck \
kbuild: add 'headers' target to build up uapi headers in usr/include In Linux build system, build targets and installation targets are separated. Examples are: - 'make vmlinux' -> 'make install' - 'make modules' -> 'make modules_install' - 'make dtbs' -> 'make dtbs_install' - 'make vdso' -> 'make vdso_install' The intention is to run the build targets under the normal privilege, then the installation targets under the root privilege since we need the write permission to the system directories. We have 'make headers_install' but the corresponding 'make headers' stage does not exist. The purpose of headers_install is to provide the kernel interface to C library. So, nobody would try to install headers to /usr/include directly. If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run, some build artifacts in the kernel tree would be owned by root because some of uapi headers are generated by 'uapi-asm-generic', 'archheaders' targets. Anyway, I believe it makes sense to split the header installation into two stages. [1] 'make headers' Process headers in uapi directories by scripts/headers_install.sh and copy them to usr/include [2] 'make headers_install' Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include For the backward compatibility, 'headers_install' depends on 'headers'. Some samples expect uapi headers in usr/include. So, the 'headers' target is useful to build up them in the fixed location usr/include irrespective of INSTALL_HDR_PATH. Another benefit is to stop polluting the final destination with the time-stamp files '.install' and '.check'. Maybe you can see them in your toolchains. Lastly, my main motivation is to prepare for compile-testing uapi headers. To build something, we have to save an object and .*.cmd somewhere. The usr/include/ will be the work directory for that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-04 10:14:02 +00:00
$(version_h) headers headers_% archheaders archscripts \
%asm-generic kernelversion %src-pkg dt_binding_check \
outputmakefile rustavailable rustfmt rustfmtcheck
no-sync-config-targets := $(no-dot-config-targets) %install modules_sign kernelrelease \
image_name
single-targets := %.a %.i %.ko %.lds %.ll %.lst %.mod %.o %.rsi %.s %.symtypes %/
config-build :=
mixed-build :=
need-config := 1
may-sync-config := 1
kbuild: make single targets work more correctly Currently, the single target build directly descends into the directory of the target. For example, $ make foo/bar/baz.o ... directly descends into foo/bar/. On the other hand, the normal build usually descends one directory at a time, i.e. descends into foo/, and then foo/bar/. This difference causes some problems. [1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles The options in subdir-{as,cc}flags-y take effect in the current and its sub-directories. In other words, they are inherited downward. In the example above, the single target will miss subdir-{as,cc}flags-y if they are defined in foo/Makefile. [2] could be built in a different directory As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can handle files that are spread over several sub-directories. The build rule of foo/bar/baz.o may not necessarily be specified in foo/bar/Makefile. It might be specifies in foo/Makefile as follows: [foo/Makefile] obj-y := bar/baz.o This often happens when a module is so big that its source files are divided into sub-directories. In this case, there is no Makefile in the foo/bar/ directory, yet the single target descends into foo/bar/, then fails due to the missing Makefile. You can still do 'make foo/bar/' for partial building, but cannot do 'make foo/bar/baz.s'. I believe the single target '%.s' is a useful feature for inspecting the compiler output. Some modules work around this issue by putting an empty Makefile in every sub-directory. This commit fixes those problems by making the single target build descend in the same way as the normal build does. Another change is the single target build will observe the CONFIG options. Previously, it allowed users to build the foo.o even when the corresponding CONFIG_FOO is disabled: obj-$(CONFIG_FOO) += foo.o In the new behavior, the single target build will just fail and show "No rule to make target ..." (or "Nothing to be done for ..." if the stale object already exists, but cannot be updated). The disadvantage of this commit is the build speed. Now that the single target build visits every directory and parses lots of Makefiles, it is slower than before. (But, I hope it will not be too slow.) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14 15:19:18 +00:00
single-build :=
ifneq ($(filter $(no-dot-config-targets), $(MAKECMDGOALS)),)
ifeq ($(filter-out $(no-dot-config-targets), $(MAKECMDGOALS)),)
need-config :=
endif
endif
kbuild: do not update config when running install targets "make syncconfig" is automatically invoked when any of the following happens: - .config is updated - any of Kconfig files is updated - any of environment variables referenced in Kconfig is changed Then, it updates configuration files such as include/config/auto.conf include/generated/autoconf.h, etc. Even install targets (install, modules_install, etc.) are no exception. However, they should never ever modify the source tree. Install targets are often run with root privileges. Once those configuration files are owned by root, "make mrproper" would end up with permission error. Install targets should just copy things blindly. They should not care whether the configuration is up-to-date or not. This makes more sense because we are interested in the configuration that was used in the previous kernel building. This issue has existed since before, but rarely happened. I expect more chance where people are hit by this; with the new Kconfig syntax extension, the .config now contains the compiler information. If you cross-compile the kernel with CROSS_COMPILE, but forget to pass it for "make install", you meet "any of environment variables referenced in Kconfig is changed" because $(CC) is referenced in Kconfig. Another scenario is the compiler upgrade before the installation. Install targets need the configuration. "make modules_install" refer to CONFIG_MODULES etc. "make dtbs_install" also needs CONFIG_ARCH_* to decide which dtb files to install. However, the auto-update of the configuration files should be avoided. We already do this for external modules. Now, Make targets are categorized into 3 groups: [1] Do not need the kernel configuration at all help, coccicheck, headers_install etc. [2] Need the latest kernel configuration If new config options are added, Kconfig will show prompt to ask user's selection. Build targets such as vmlinux, in-kernel modules are the cases. [3] Need the kernel configuration, but do not want to update it Install targets except headers_install, and external modules are the cases. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 07:46:34 +00:00
ifneq ($(filter $(no-sync-config-targets), $(MAKECMDGOALS)),)
ifeq ($(filter-out $(no-sync-config-targets), $(MAKECMDGOALS)),)
may-sync-config :=
endif
kbuild: do not update config when running install targets "make syncconfig" is automatically invoked when any of the following happens: - .config is updated - any of Kconfig files is updated - any of environment variables referenced in Kconfig is changed Then, it updates configuration files such as include/config/auto.conf include/generated/autoconf.h, etc. Even install targets (install, modules_install, etc.) are no exception. However, they should never ever modify the source tree. Install targets are often run with root privileges. Once those configuration files are owned by root, "make mrproper" would end up with permission error. Install targets should just copy things blindly. They should not care whether the configuration is up-to-date or not. This makes more sense because we are interested in the configuration that was used in the previous kernel building. This issue has existed since before, but rarely happened. I expect more chance where people are hit by this; with the new Kconfig syntax extension, the .config now contains the compiler information. If you cross-compile the kernel with CROSS_COMPILE, but forget to pass it for "make install", you meet "any of environment variables referenced in Kconfig is changed" because $(CC) is referenced in Kconfig. Another scenario is the compiler upgrade before the installation. Install targets need the configuration. "make modules_install" refer to CONFIG_MODULES etc. "make dtbs_install" also needs CONFIG_ARCH_* to decide which dtb files to install. However, the auto-update of the configuration files should be avoided. We already do this for external modules. Now, Make targets are categorized into 3 groups: [1] Do not need the kernel configuration at all help, coccicheck, headers_install etc. [2] Need the latest kernel configuration If new config options are added, Kconfig will show prompt to ask user's selection. Build targets such as vmlinux, in-kernel modules are the cases. [3] Need the kernel configuration, but do not want to update it Install targets except headers_install, and external modules are the cases. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 07:46:34 +00:00
endif
need-compiler := $(may-sync-config)
kbuild: do not update config when running install targets "make syncconfig" is automatically invoked when any of the following happens: - .config is updated - any of Kconfig files is updated - any of environment variables referenced in Kconfig is changed Then, it updates configuration files such as include/config/auto.conf include/generated/autoconf.h, etc. Even install targets (install, modules_install, etc.) are no exception. However, they should never ever modify the source tree. Install targets are often run with root privileges. Once those configuration files are owned by root, "make mrproper" would end up with permission error. Install targets should just copy things blindly. They should not care whether the configuration is up-to-date or not. This makes more sense because we are interested in the configuration that was used in the previous kernel building. This issue has existed since before, but rarely happened. I expect more chance where people are hit by this; with the new Kconfig syntax extension, the .config now contains the compiler information. If you cross-compile the kernel with CROSS_COMPILE, but forget to pass it for "make install", you meet "any of environment variables referenced in Kconfig is changed" because $(CC) is referenced in Kconfig. Another scenario is the compiler upgrade before the installation. Install targets need the configuration. "make modules_install" refer to CONFIG_MODULES etc. "make dtbs_install" also needs CONFIG_ARCH_* to decide which dtb files to install. However, the auto-update of the configuration files should be avoided. We already do this for external modules. Now, Make targets are categorized into 3 groups: [1] Do not need the kernel configuration at all help, coccicheck, headers_install etc. [2] Need the latest kernel configuration If new config options are added, Kconfig will show prompt to ask user's selection. Build targets such as vmlinux, in-kernel modules are the cases. [3] Need the kernel configuration, but do not want to update it Install targets except headers_install, and external modules are the cases. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 07:46:34 +00:00
ifneq ($(KBUILD_EXTMOD),)
may-sync-config :=
kbuild: do not update config when running install targets "make syncconfig" is automatically invoked when any of the following happens: - .config is updated - any of Kconfig files is updated - any of environment variables referenced in Kconfig is changed Then, it updates configuration files such as include/config/auto.conf include/generated/autoconf.h, etc. Even install targets (install, modules_install, etc.) are no exception. However, they should never ever modify the source tree. Install targets are often run with root privileges. Once those configuration files are owned by root, "make mrproper" would end up with permission error. Install targets should just copy things blindly. They should not care whether the configuration is up-to-date or not. This makes more sense because we are interested in the configuration that was used in the previous kernel building. This issue has existed since before, but rarely happened. I expect more chance where people are hit by this; with the new Kconfig syntax extension, the .config now contains the compiler information. If you cross-compile the kernel with CROSS_COMPILE, but forget to pass it for "make install", you meet "any of environment variables referenced in Kconfig is changed" because $(CC) is referenced in Kconfig. Another scenario is the compiler upgrade before the installation. Install targets need the configuration. "make modules_install" refer to CONFIG_MODULES etc. "make dtbs_install" also needs CONFIG_ARCH_* to decide which dtb files to install. However, the auto-update of the configuration files should be avoided. We already do this for external modules. Now, Make targets are categorized into 3 groups: [1] Do not need the kernel configuration at all help, coccicheck, headers_install etc. [2] Need the latest kernel configuration If new config options are added, Kconfig will show prompt to ask user's selection. Build targets such as vmlinux, in-kernel modules are the cases. [3] Need the kernel configuration, but do not want to update it Install targets except headers_install, and external modules are the cases. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 07:46:34 +00:00
endif
ifeq ($(KBUILD_EXTMOD),)
ifneq ($(filter %config,$(MAKECMDGOALS)),)
config-build := 1
ifneq ($(words $(MAKECMDGOALS)),1)
mixed-build := 1
endif
endif
endif
kbuild: make single targets work more correctly Currently, the single target build directly descends into the directory of the target. For example, $ make foo/bar/baz.o ... directly descends into foo/bar/. On the other hand, the normal build usually descends one directory at a time, i.e. descends into foo/, and then foo/bar/. This difference causes some problems. [1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles The options in subdir-{as,cc}flags-y take effect in the current and its sub-directories. In other words, they are inherited downward. In the example above, the single target will miss subdir-{as,cc}flags-y if they are defined in foo/Makefile. [2] could be built in a different directory As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can handle files that are spread over several sub-directories. The build rule of foo/bar/baz.o may not necessarily be specified in foo/bar/Makefile. It might be specifies in foo/Makefile as follows: [foo/Makefile] obj-y := bar/baz.o This often happens when a module is so big that its source files are divided into sub-directories. In this case, there is no Makefile in the foo/bar/ directory, yet the single target descends into foo/bar/, then fails due to the missing Makefile. You can still do 'make foo/bar/' for partial building, but cannot do 'make foo/bar/baz.s'. I believe the single target '%.s' is a useful feature for inspecting the compiler output. Some modules work around this issue by putting an empty Makefile in every sub-directory. This commit fixes those problems by making the single target build descend in the same way as the normal build does. Another change is the single target build will observe the CONFIG options. Previously, it allowed users to build the foo.o even when the corresponding CONFIG_FOO is disabled: obj-$(CONFIG_FOO) += foo.o In the new behavior, the single target build will just fail and show "No rule to make target ..." (or "Nothing to be done for ..." if the stale object already exists, but cannot be updated). The disadvantage of this commit is the build speed. Now that the single target build visits every directory and parses lots of Makefiles, it is slower than before. (But, I hope it will not be too slow.) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14 15:19:18 +00:00
# We cannot build single targets and the others at the same time
ifneq ($(filter $(single-targets), $(MAKECMDGOALS)),)
single-build := 1
ifneq ($(filter-out $(single-targets), $(MAKECMDGOALS)),)
mixed-build := 1
endif
kbuild: make single targets work more correctly Currently, the single target build directly descends into the directory of the target. For example, $ make foo/bar/baz.o ... directly descends into foo/bar/. On the other hand, the normal build usually descends one directory at a time, i.e. descends into foo/, and then foo/bar/. This difference causes some problems. [1] miss subdir-asflags-y, subdir-ccflags-y in upper Makefiles The options in subdir-{as,cc}flags-y take effect in the current and its sub-directories. In other words, they are inherited downward. In the example above, the single target will miss subdir-{as,cc}flags-y if they are defined in foo/Makefile. [2] could be built in a different directory As Documentation/kbuild/modules.rst section 4.3 says, Kbuild can handle files that are spread over several sub-directories. The build rule of foo/bar/baz.o may not necessarily be specified in foo/bar/Makefile. It might be specifies in foo/Makefile as follows: [foo/Makefile] obj-y := bar/baz.o This often happens when a module is so big that its source files are divided into sub-directories. In this case, there is no Makefile in the foo/bar/ directory, yet the single target descends into foo/bar/, then fails due to the missing Makefile. You can still do 'make foo/bar/' for partial building, but cannot do 'make foo/bar/baz.s'. I believe the single target '%.s' is a useful feature for inspecting the compiler output. Some modules work around this issue by putting an empty Makefile in every sub-directory. This commit fixes those problems by making the single target build descend in the same way as the normal build does. Another change is the single target build will observe the CONFIG options. Previously, it allowed users to build the foo.o even when the corresponding CONFIG_FOO is disabled: obj-$(CONFIG_FOO) += foo.o In the new behavior, the single target build will just fail and show "No rule to make target ..." (or "Nothing to be done for ..." if the stale object already exists, but cannot be updated). The disadvantage of this commit is the build speed. Now that the single target build visits every directory and parses lots of Makefiles, it is slower than before. (But, I hope it will not be too slow.) Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-08-14 15:19:18 +00:00
endif
# For "make -j clean all", "make -j mrproper defconfig all", etc.
ifneq ($(filter $(clean-targets),$(MAKECMDGOALS)),)
ifneq ($(filter-out $(clean-targets),$(MAKECMDGOALS)),)
mixed-build := 1
endif
endif
# install and modules_install need also be processed one by one
ifneq ($(filter install,$(MAKECMDGOALS)),)
ifneq ($(filter modules_install,$(MAKECMDGOALS)),)
mixed-build := 1
endif
endif
ifdef mixed-build
# ===========================================================================
# We're called with mixed targets (*config and build targets).
# Handle them one by one.
PHONY += $(MAKECMDGOALS) __build_one_by_one
$(MAKECMDGOALS): __build_one_by_one
@:
__build_one_by_one:
$(Q)set -e; \
for i in $(MAKECMDGOALS); do \
$(MAKE) -f $(srctree)/Makefile $$i; \
done
else # !mixed-build
include $(srctree)/scripts/Kbuild.include
# Read KERNELRELEASE from include/config/kernel.release (if it exists)
KERNELRELEASE = $(call read-file, include/config/kernel.release)
KERNELVERSION = $(VERSION)$(if $(PATCHLEVEL),.$(PATCHLEVEL)$(if $(SUBLEVEL),.$(SUBLEVEL)))$(EXTRAVERSION)
export VERSION PATCHLEVEL SUBLEVEL KERNELRELEASE KERNELVERSION
include $(srctree)/scripts/subarch.include
# Cross compiling and selecting different set of gcc/bin-utils
# ---------------------------------------------------------------------------
#
# When performing cross compilation for other architectures ARCH shall be set
# to the target architecture. (See arch/* for the possibilities).
# ARCH can be set during invocation of make:
# make ARCH=arm64
# Another way is to have ARCH set in the environment.
# The default ARCH is the host where make is executed.
# CROSS_COMPILE specify the prefix used for all executables used
# during compilation. Only gcc and related bin-utils executables
# are prefixed with $(CROSS_COMPILE).
# CROSS_COMPILE can be set on the command line
# make CROSS_COMPILE=aarch64-linux-gnu-
# Alternatively CROSS_COMPILE can be set in the environment.
# Default value for CROSS_COMPILE is not to prefix executables
# Note: Some architectures assign CROSS_COMPILE in their arch/*/Makefile
ARCH ?= $(SUBARCH)
# Architecture as present in compile.h
UTS_MACHINE := $(ARCH)
SRCARCH := $(ARCH)
# Additional ARCH settings for x86
ifeq ($(ARCH),i386)
SRCARCH := x86
endif
ifeq ($(ARCH),x86_64)
SRCARCH := x86
endif
# Additional ARCH settings for sparc
ifeq ($(ARCH),sparc32)
SRCARCH := sparc
endif
ifeq ($(ARCH),sparc64)
SRCARCH := sparc
endif
# Additional ARCH settings for parisc
ifeq ($(ARCH),parisc64)
SRCARCH := parisc
endif
export cross_compiling :=
ifneq ($(SRCARCH),$(SUBARCH))
cross_compiling := 1
endif
KCONFIG_CONFIG ?= .config
export KCONFIG_CONFIG
# SHELL used by kbuild
CONFIG_SHELL := sh
HOST_LFS_CFLAGS := $(shell getconf LFS_CFLAGS 2>/dev/null)
HOST_LFS_LDFLAGS := $(shell getconf LFS_LDFLAGS 2>/dev/null)
HOST_LFS_LIBS := $(shell getconf LFS_LIBS 2>/dev/null)
kbuild: support LLVM=1 to switch the default tools to Clang/LLVM As Documentation/kbuild/llvm.rst implies, building the kernel with a full set of LLVM tools gets very verbose and unwieldy. Provide a single switch LLVM=1 to use Clang and LLVM tools instead of GCC and Binutils. You can pass it from the command line or as an environment variable. Please note LLVM=1 does not turn on the integrated assembler. You need to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the integrated assembler, I think we can make it default. We discussed what we need, and we agreed to go with a simple boolean flag that switches both target and host tools: https://lkml.org/lkml/2020/3/28/494 https://lkml.org/lkml/2020/4/3/43 Some items discussed, but not adopted: - LLVM_DIR When multiple versions of LLVM are installed, I just thought supporting LLVM_DIR=/path/to/my/llvm/bin/ might be useful. CC = $(LLVM_DIR)clang LD = $(LLVM_DIR)ld.lld ... However, we can handle this by modifying PATH. So, we decided to not do this. - LLVM_SUFFIX Some distributions (e.g. Debian) package specific versions of LLVM with naming conventions that use the version as a suffix. CC = clang$(LLVM_SUFFIX) LD = ld.lld(LLVM_SUFFIX) ... will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc., but the suffixed versions in /usr/bin/ are symlinks to binaries in /usr/lib/llvm-#/bin/, so this can also be handled by PATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-08 01:36:23 +00:00
ifneq ($(LLVM),)
kbuild: Make $(LLVM) more flexible The LLVM make variable allows a developer to quickly switch between the GNU and LLVM tools. However, it does not handle versioned binaries, such as the ones shipped by Debian, as LLVM=1 just defines the tool variables with the unversioned binaries. There was some discussion during the review of the patch that introduces LLVM=1 around versioned binaries, ultimately coming to the conclusion that developers can just add the folder that contains the unversioned binaries to their PATH, as Debian's versioned suffixed binaries are really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin: $ realpath /usr/bin/clang-14 /usr/lib/llvm-14/bin/clang $ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1 However, that can be cumbersome to developers who are constantly testing series with different toolchains and versions. It is simple enough to support these versioned binaries directly in the Kbuild system by allowing the developer to specify the version suffix with LLVM=, which is shorter than the above suggestion: $ make ... LLVM=-14 It does not change the meaning of LLVM=1 (which will continue to use unversioned binaries) and it does not add too much additional complexity to the existing $(LLVM) code, while allowing developers to quickly test their series with different versions of the whole LLVM suite of tools. Some developers may build LLVM from source but not add the binaries to their PATH, as they may not want to use that toolchain systemwide. Support those developers by allowing them to supply the directory that the LLVM tools are available in, as it is no more complex to support than the version suffix change above. $ make ... LLVM=/path/to/llvm/ Update and reorder the documentation to reflect these new additions. At the same time, notate that LLVM=0 is not the same as just omitting it altogether, which has confused people in the past. Link: https://lore.kernel.org/r/20200317215515.226917-1-ndesaulniers@google.com/ Link: https://lore.kernel.org/r/20220224151322.072632223@infradead.org/ Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-03-04 17:08:14 +00:00
ifneq ($(filter %/,$(LLVM)),)
LLVM_PREFIX := $(LLVM)
else ifneq ($(filter -%,$(LLVM)),)
LLVM_SUFFIX := $(LLVM)
endif
HOSTCC = $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
HOSTCXX = $(LLVM_PREFIX)clang++$(LLVM_SUFFIX)
kbuild: support LLVM=1 to switch the default tools to Clang/LLVM As Documentation/kbuild/llvm.rst implies, building the kernel with a full set of LLVM tools gets very verbose and unwieldy. Provide a single switch LLVM=1 to use Clang and LLVM tools instead of GCC and Binutils. You can pass it from the command line or as an environment variable. Please note LLVM=1 does not turn on the integrated assembler. You need to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the integrated assembler, I think we can make it default. We discussed what we need, and we agreed to go with a simple boolean flag that switches both target and host tools: https://lkml.org/lkml/2020/3/28/494 https://lkml.org/lkml/2020/4/3/43 Some items discussed, but not adopted: - LLVM_DIR When multiple versions of LLVM are installed, I just thought supporting LLVM_DIR=/path/to/my/llvm/bin/ might be useful. CC = $(LLVM_DIR)clang LD = $(LLVM_DIR)ld.lld ... However, we can handle this by modifying PATH. So, we decided to not do this. - LLVM_SUFFIX Some distributions (e.g. Debian) package specific versions of LLVM with naming conventions that use the version as a suffix. CC = clang$(LLVM_SUFFIX) LD = ld.lld(LLVM_SUFFIX) ... will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc., but the suffixed versions in /usr/bin/ are symlinks to binaries in /usr/lib/llvm-#/bin/, so this can also be handled by PATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-08 01:36:23 +00:00
else
HOSTCC = gcc
HOSTCXX = g++
endif
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
HOSTRUSTC = rustc
HOSTPKG_CONFIG = pkg-config
kbuild: add infrastructure to build userspace programs Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154), but it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] are often used for building the kernel, but they do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use the 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-04-29 03:45:14 +00:00
KBUILD_USERHOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes \
-O2 -fomit-frame-pointer -std=gnu11
KBUILD_USERCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(USERCFLAGS)
KBUILD_USERLDFLAGS := $(USERLDFLAGS)
kbuild: add infrastructure to build userspace programs Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154), but it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] are often used for building the kernel, but they do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use the 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-04-29 03:45:14 +00:00
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# These flags apply to all Rust code in the tree, including the kernel and
# host programs.
export rust_common_flags := --edition=2021 \
-Zbinary_dep_depinfo=y \
-Dunsafe_op_in_unsafe_fn -Drust_2018_idioms \
-Dunreachable_pub -Dnon_ascii_idents \
-Wmissing_docs \
-Drustdoc::missing_crate_level_docs \
-Dclippy::correctness -Dclippy::style \
-Dclippy::suspicious -Dclippy::complexity \
-Dclippy::perf \
-Dclippy::let_unit_value -Dclippy::mut_mut \
-Dclippy::needless_bitwise_bool \
-Dclippy::needless_continue \
rust: enable `no_mangle_with_rust_abi` Clippy lint Introduced in Rust 1.69.0 [1], this lint prevents forgetting to set the C ABI when using `#[no_mangle]` (or thinking it is implied). For instance, it would have prevented the issue [2] fixed by commit c682e4c37d2b ("rust: kernel: Mark rust_fmt_argument as extern "C""). error: `#[no_mangle]` set on a function with the default (`Rust`) ABI --> rust/kernel/print.rs:21:1 | 21 | / unsafe fn rust_fmt_argument( 22 | | buf: *mut c_char, 23 | | end: *mut c_char, 24 | | ptr: *const c_void, 25 | | ) -> *mut c_char { | |________________^ | = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#no_mangle_with_rust_abi = note: requested on the command line with `-D clippy::no-mangle-with-rust-abi` help: set an ABI | 21 | unsafe extern "C" fn rust_fmt_argument( | ++++++++++ help: or explicitly set the default | 21 | unsafe extern "Rust" fn rust_fmt_argument( | +++++++++++++ Thus enable it. In rare cases, we may need to use the Rust ABI even with `#[no_mangle]` (e.g. one case, before 1.71.0, would have been the `__rust_*` functions). In those cases, we would need to `#[allow(...)]` the lint, since using `extern "Rust"` explicitly (as the compiler suggests) currently gets overwritten by `rustfmt` [3]. Link: https://github.com/rust-lang/rust-clippy/issues/10347 [1] Link: https://github.com/Rust-for-Linux/linux/pull/967 [2] Link: https://github.com/rust-lang/rustfmt/issues/5701 [3] Reviewed-by: Trevor Gross <tmgross@umich.edu> Reviewed-by: Gary Guo <gary@garyguo.net> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Link: https://lore.kernel.org/r/20230729220317.416771-2-ojeda@kernel.org Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2023-07-29 22:03:17 +00:00
-Dclippy::no_mangle_with_rust_abi \
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
-Wclippy::dbg_macro
KBUILD_HOSTCFLAGS := $(KBUILD_USERHOSTCFLAGS) $(HOST_LFS_CFLAGS) $(HOSTCFLAGS)
kbuild: add -Wall to KBUILD_HOSTCXXFLAGS Add -Wall to catch more warnings for C++ host programs. When I submitted the previous version, the 0-day bot reported -Wc++11-compat warnings for old GCC: HOSTCXX -fPIC scripts/gcc-plugins/latent_entropy_plugin.o In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/tm.h:28:0, from scripts/gcc-plugins/gcc-common.h:15, from scripts/gcc-plugins/latent_entropy_plugin.c:78: /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/config/elfos.h:102:21: warning: C++11 requires a space between string literal and macro [-Wc++11-compat] fprintf ((FILE), "%s"HOST_WIDE_INT_PRINT_UNSIGNED"\n",\ ^ /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/config/elfos.h:170:24: warning: C++11 requires a space between string literal and macro [-Wc++11-compat] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ In file included from /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/tm.h:42:0, from scripts/gcc-plugins/gcc-common.h:15, from scripts/gcc-plugins/latent_entropy_plugin.c:78: /usr/lib/gcc/x86_64-linux-gnu/4.8/plugin/include/defaults.h:126:24: warning: C++11 requires a space between string literal and macro [-Wc++11-compat] fprintf ((FILE), ","HOST_WIDE_INT_PRINT_UNSIGNED",%u\n", \ ^ The source of the warnings is in the plugin headers, so we have no control of it. I just suppressed them by adding -Wno-c++11-compat to scripts/gcc-plugins/Makefile. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Kees Cook <keescook@chromium.org>
2020-03-25 03:14:32 +00:00
KBUILD_HOSTCXXFLAGS := -Wall -O2 $(HOST_LFS_CFLAGS) $(HOSTCXXFLAGS)
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_HOSTRUSTFLAGS := $(rust_common_flags) -O -Cstrip=debuginfo \
-Zallow-features= $(HOSTRUSTFLAGS)
KBUILD_HOSTLDFLAGS := $(HOST_LFS_LDFLAGS) $(HOSTLDFLAGS)
KBUILD_HOSTLDLIBS := $(HOST_LFS_LIBS) $(HOSTLDLIBS)
# Make variables (CC, etc...)
CPP = $(CC) -E
kbuild: support LLVM=1 to switch the default tools to Clang/LLVM As Documentation/kbuild/llvm.rst implies, building the kernel with a full set of LLVM tools gets very verbose and unwieldy. Provide a single switch LLVM=1 to use Clang and LLVM tools instead of GCC and Binutils. You can pass it from the command line or as an environment variable. Please note LLVM=1 does not turn on the integrated assembler. You need to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the integrated assembler, I think we can make it default. We discussed what we need, and we agreed to go with a simple boolean flag that switches both target and host tools: https://lkml.org/lkml/2020/3/28/494 https://lkml.org/lkml/2020/4/3/43 Some items discussed, but not adopted: - LLVM_DIR When multiple versions of LLVM are installed, I just thought supporting LLVM_DIR=/path/to/my/llvm/bin/ might be useful. CC = $(LLVM_DIR)clang LD = $(LLVM_DIR)ld.lld ... However, we can handle this by modifying PATH. So, we decided to not do this. - LLVM_SUFFIX Some distributions (e.g. Debian) package specific versions of LLVM with naming conventions that use the version as a suffix. CC = clang$(LLVM_SUFFIX) LD = ld.lld(LLVM_SUFFIX) ... will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc., but the suffixed versions in /usr/bin/ are symlinks to binaries in /usr/lib/llvm-#/bin/, so this can also be handled by PATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-08 01:36:23 +00:00
ifneq ($(LLVM),)
kbuild: Make $(LLVM) more flexible The LLVM make variable allows a developer to quickly switch between the GNU and LLVM tools. However, it does not handle versioned binaries, such as the ones shipped by Debian, as LLVM=1 just defines the tool variables with the unversioned binaries. There was some discussion during the review of the patch that introduces LLVM=1 around versioned binaries, ultimately coming to the conclusion that developers can just add the folder that contains the unversioned binaries to their PATH, as Debian's versioned suffixed binaries are really just symlinks to the unversioned binaries in /usr/lib/llvm-#/bin: $ realpath /usr/bin/clang-14 /usr/lib/llvm-14/bin/clang $ PATH=/usr/lib/llvm-14/bin:$PATH make ... LLVM=1 However, that can be cumbersome to developers who are constantly testing series with different toolchains and versions. It is simple enough to support these versioned binaries directly in the Kbuild system by allowing the developer to specify the version suffix with LLVM=, which is shorter than the above suggestion: $ make ... LLVM=-14 It does not change the meaning of LLVM=1 (which will continue to use unversioned binaries) and it does not add too much additional complexity to the existing $(LLVM) code, while allowing developers to quickly test their series with different versions of the whole LLVM suite of tools. Some developers may build LLVM from source but not add the binaries to their PATH, as they may not want to use that toolchain systemwide. Support those developers by allowing them to supply the directory that the LLVM tools are available in, as it is no more complex to support than the version suffix change above. $ make ... LLVM=/path/to/llvm/ Update and reorder the documentation to reflect these new additions. At the same time, notate that LLVM=0 is not the same as just omitting it altogether, which has confused people in the past. Link: https://lore.kernel.org/r/20200317215515.226917-1-ndesaulniers@google.com/ Link: https://lore.kernel.org/r/20220224151322.072632223@infradead.org/ Suggested-by: Masahiro Yamada <masahiroy@kernel.org> Suggested-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2022-03-04 17:08:14 +00:00
CC = $(LLVM_PREFIX)clang$(LLVM_SUFFIX)
LD = $(LLVM_PREFIX)ld.lld$(LLVM_SUFFIX)
AR = $(LLVM_PREFIX)llvm-ar$(LLVM_SUFFIX)
NM = $(LLVM_PREFIX)llvm-nm$(LLVM_SUFFIX)
OBJCOPY = $(LLVM_PREFIX)llvm-objcopy$(LLVM_SUFFIX)
OBJDUMP = $(LLVM_PREFIX)llvm-objdump$(LLVM_SUFFIX)
READELF = $(LLVM_PREFIX)llvm-readelf$(LLVM_SUFFIX)
STRIP = $(LLVM_PREFIX)llvm-strip$(LLVM_SUFFIX)
kbuild: support LLVM=1 to switch the default tools to Clang/LLVM As Documentation/kbuild/llvm.rst implies, building the kernel with a full set of LLVM tools gets very verbose and unwieldy. Provide a single switch LLVM=1 to use Clang and LLVM tools instead of GCC and Binutils. You can pass it from the command line or as an environment variable. Please note LLVM=1 does not turn on the integrated assembler. You need to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the integrated assembler, I think we can make it default. We discussed what we need, and we agreed to go with a simple boolean flag that switches both target and host tools: https://lkml.org/lkml/2020/3/28/494 https://lkml.org/lkml/2020/4/3/43 Some items discussed, but not adopted: - LLVM_DIR When multiple versions of LLVM are installed, I just thought supporting LLVM_DIR=/path/to/my/llvm/bin/ might be useful. CC = $(LLVM_DIR)clang LD = $(LLVM_DIR)ld.lld ... However, we can handle this by modifying PATH. So, we decided to not do this. - LLVM_SUFFIX Some distributions (e.g. Debian) package specific versions of LLVM with naming conventions that use the version as a suffix. CC = clang$(LLVM_SUFFIX) LD = ld.lld(LLVM_SUFFIX) ... will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc., but the suffixed versions in /usr/bin/ are symlinks to binaries in /usr/lib/llvm-#/bin/, so this can also be handled by PATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-08 01:36:23 +00:00
else
CC = $(CROSS_COMPILE)gcc
LD = $(CROSS_COMPILE)ld
AR = $(CROSS_COMPILE)ar
NM = $(CROSS_COMPILE)nm
OBJCOPY = $(CROSS_COMPILE)objcopy
OBJDUMP = $(CROSS_COMPILE)objdump
READELF = $(CROSS_COMPILE)readelf
kbuild: support LLVM=1 to switch the default tools to Clang/LLVM As Documentation/kbuild/llvm.rst implies, building the kernel with a full set of LLVM tools gets very verbose and unwieldy. Provide a single switch LLVM=1 to use Clang and LLVM tools instead of GCC and Binutils. You can pass it from the command line or as an environment variable. Please note LLVM=1 does not turn on the integrated assembler. You need to pass LLVM_IAS=1 to use it. When the upstream kernel is ready for the integrated assembler, I think we can make it default. We discussed what we need, and we agreed to go with a simple boolean flag that switches both target and host tools: https://lkml.org/lkml/2020/3/28/494 https://lkml.org/lkml/2020/4/3/43 Some items discussed, but not adopted: - LLVM_DIR When multiple versions of LLVM are installed, I just thought supporting LLVM_DIR=/path/to/my/llvm/bin/ might be useful. CC = $(LLVM_DIR)clang LD = $(LLVM_DIR)ld.lld ... However, we can handle this by modifying PATH. So, we decided to not do this. - LLVM_SUFFIX Some distributions (e.g. Debian) package specific versions of LLVM with naming conventions that use the version as a suffix. CC = clang$(LLVM_SUFFIX) LD = ld.lld(LLVM_SUFFIX) ... will allow a user to pass LLVM_SUFFIX=-11 to use clang-11 etc., but the suffixed versions in /usr/bin/ are symlinks to binaries in /usr/lib/llvm-#/bin/, so this can also be handled by PATH. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <natechancellor@gmail.com> Tested-by: Nathan Chancellor <natechancellor@gmail.com> # build Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-04-08 01:36:23 +00:00
STRIP = $(CROSS_COMPILE)strip
endif
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
RUSTC = rustc
RUSTDOC = rustdoc
RUSTFMT = rustfmt
CLIPPY_DRIVER = clippy-driver
BINDGEN = bindgen
CARGO = cargo
kbuild: add ability to generate BTF type info for vmlinux This patch adds new config option to trigger generation of BTF type information from DWARF debuginfo for vmlinux and kernel modules through pahole, which in turn relies on libbpf for btf_dedup() algorithm. The intent is to record compact type information of all types used inside kernel, including all the structs/unions/typedefs/etc. This enables BPF's compile-once-run-everywhere ([0]) approach, in which tracing programs that are inspecting kernel's internal data (e.g., struct task_struct) can be compiled on a system running some kernel version, but would be possible to run on other kernel versions (and configurations) without recompilation, even if the layout of structs changed and/or some of the fields were added, removed, or renamed. This is only possible if BPF loader can get kernel type info to adjust all the offsets correctly. This patch is a first time in this direction, making sure that BTF type info is part of Linux kernel image in non-loadable ELF section. BTF deduplication ([1]) algorithm typically provides 100x savings compared to DWARF data, so resulting .BTF section is not big as is typically about 2MB in size. [0] http://vger.kernel.org/lpc-bpf2018.html#session-2 [1] https://facebookmicrosites.github.io/bpf/blog/2018/11/14/btf-enhancement.html Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Alexei Starovoitov <ast@fb.com> Cc: Yonghong Song <yhs@fb.com> Cc: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Andrii Nakryiko <andriin@fb.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
2019-04-02 16:49:50 +00:00
PAHOLE = pahole
RESOLVE_BTFIDS = $(objtree)/tools/bpf/resolve_btfids/resolve_btfids
LEX = flex
YACC = bison
AWK = awk
kbuild: use INSTALLKERNEL to select customized installkernel script Replace the use of CROSS_COMPILE to select a customized installkernel script with the possibility to set INSTALLKERNEL to select a custom installkernel script when running make: make INSTALLKERNEL=arm-installkernel install With this patch we are now more consistent across different architectures - they did not all support use of CROSS_COMPILE. The use of CROSS_COMPILE was a hack as this really belongs to gcc/binutils and the installkernel script does not change just because we change toolchain. The use of CROSS_COMPILE caused troubles with an upcoming patch that saves CROSS_COMPILE when a kernel is built - it would no longer be installable. [Thanks to Peter Z. for this hint] This patch undos what Ian did in commit: 0f8e2d62fa04441cd12c08ce521e84e5bd3f8a46 ("use ${CROSS_COMPILE}installkernel in arch/*/boot/install.sh") The patch has been lightly tested on x86 only - but all changes looks obvious. Acked-by: Peter Zijlstra <peterz@infradead.org> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Russell King <linux@arm.linux.org.uk> [arm] Acked-by: Paul Mundt <lethal@linux-sh.org> [sh] Acked-by: "H. Peter Anvin" <hpa@zytor.com> [x86] Cc: Ian Campbell <icampbell@arcom.com> Cc: Tony Luck <tony.luck@intel.com> [ia64] Cc: Fenghua Yu <fenghua.yu@intel.com> [ia64] Cc: Hirokazu Takata <takata@linux-m32r.org> [m32r] Cc: Geert Uytterhoeven <geert@linux-m68k.org> [m68k] Cc: Kyle McMartin <kyle@mcmartin.ca> [parisc] Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> [powerpc] Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390] Cc: Thomas Gleixner <tglx@linutronix.de> [x86] Cc: Ingo Molnar <mingo@redhat.com> [x86] Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
2009-07-20 19:37:11 +00:00
INSTALLKERNEL := installkernel
PERL = perl
kbuild: add PYTHON2 and PYTHON3 variables The variable 'PYTHON' allows users to specify a proper executable name in case the default 'python' does not work. However, this does not address the case where both Python 2.x and 3.x scripts are used in one source tree. PEP 394 (https://www.python.org/dev/peps/pep-0394/) provides a convention for Python scripts portability. Here is a quotation: In order to tolerate differences across platforms, all new code that needs to invoke the Python interpreter should not specify 'python', but rather should specify either 'python2' or 'python3'. This distinction should be made in shebangs, when invoking from a shell script, when invoking via the system() call, or when invoking in any other context. One exception to this is scripts that are deliberately written to be source compatible with both Python 2.x and 3.x. Such scripts may continue to use python on their shebang line without affecting their portability. To meet this requirement, this commit adds new variables 'PYTHON2' and 'PYTHON3'. arch/ia64/scripts/unwcheck.py is the only script that has ever used $(PYTHON). Recent commit bd5edbe67794 ("ia64: convert unwcheck.py to python3") converted it to be compatible with both Python 2.x and 3.x, so this is the exceptional case where the use of 'python' is allowed. So, I did not touch arch/ia64/Makefile. tools/perf/Makefile.config sets PYTHON and PYTHON2 by itself, so it is not affected by this commit. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-03-13 09:12:02 +00:00
PYTHON3 = python3
CHECK = sparse
BASH = bash
KGZIP = gzip
KBZIP2 = bzip2
KLZOP = lzop
LZMA = lzma
LZ4 = lz4c
XZ = xz
ZSTD = zstd
CHECKFLAGS := -D__linux__ -Dlinux -D__STDC__ -Dunix -D__unix__ \
-Wbitwise -Wno-return-void -Wno-unknown-attribute $(CF)
NOSTDINC_FLAGS :=
kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line It is now possible to assign options to AS, CC and LD on the command line - which is only used when building modules. {A,C,LD}FLAGS_MODULE was all used both in the top-level Makefile in the arch makefiles, thus users had no way to specify additional options to AS, CC, LD when building modules without overriding the original value. Introduce a new set of variables KBUILD_{A,C,LD}FLAGS_MODULE that is used by arch specific files and free up {A,C,LD}FLAGS_MODULE so they can be assigned on the command line. All arch Makefiles that used the old variables has been updated. Note: Previously we had a MODFLAGS variable for both AS and CC. But in favour of consistency this was dropped. So in some cases arch Makefile has one assignmnet replaced by two assignmnets. Note2: MODFLAGS was not documented and is dropped without any notice. I do not expect much/any breakage from this. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [avr32] Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-07-28 15:33:09 +00:00
CFLAGS_MODULE =
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
RUSTFLAGS_MODULE =
kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line It is now possible to assign options to AS, CC and LD on the command line - which is only used when building modules. {A,C,LD}FLAGS_MODULE was all used both in the top-level Makefile in the arch makefiles, thus users had no way to specify additional options to AS, CC, LD when building modules without overriding the original value. Introduce a new set of variables KBUILD_{A,C,LD}FLAGS_MODULE that is used by arch specific files and free up {A,C,LD}FLAGS_MODULE so they can be assigned on the command line. All arch Makefiles that used the old variables has been updated. Note: Previously we had a MODFLAGS variable for both AS and CC. But in favour of consistency this was dropped. So in some cases arch Makefile has one assignmnet replaced by two assignmnets. Note2: MODFLAGS was not documented and is dropped without any notice. I do not expect much/any breakage from this. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [avr32] Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-07-28 15:33:09 +00:00
AFLAGS_MODULE =
LDFLAGS_MODULE =
CFLAGS_KERNEL =
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
RUSTFLAGS_KERNEL =
AFLAGS_KERNEL =
kbuild: export top-level LDFLAGS_vmlinux only to scripts/Makefile.vmlinux Nathan Chancellor reports that $(NM) emits an error message when GNU Make 4.4 is used to build the ARM zImage. $ make-4.4 ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- O=build defconfig zImage [snip] LD vmlinux NM System.map SORTTAB vmlinux OBJCOPY arch/arm/boot/Image Kernel: arch/arm/boot/Image is ready arm-linux-gnueabi-nm: 'arch/arm/boot/compressed/../../../../vmlinux': No such file /bin/sh: 1: arithmetic expression: expecting primary: " " LDS arch/arm/boot/compressed/vmlinux.lds AS arch/arm/boot/compressed/head.o GZIP arch/arm/boot/compressed/piggy_data AS arch/arm/boot/compressed/piggy.o CC arch/arm/boot/compressed/misc.o This occurs since GNU Make commit 98da874c4303 ("[SV 10593] Export variables to $(shell ...) commands"), and the O= option is needed to reproduce it. The generated zImage is correct despite the error message. As the commit description of 98da874c4303 [1] says, exported variables are passed down to $(shell ) functions, which means exported recursive variables might be expanded earlier than before, in the parse stage. The following test code demonstrates the change for GNU Make 4.4. [Test Makefile] $(shell echo hello > foo) export foo = $(shell cat bar/../foo) $(shell mkdir bar) all: @echo $(foo) [GNU Make 4.3] $ rm -rf bar; make-4.3 hello [GNU Make 4.4] $ rm -rf bar; make-4.4 cat: bar/../foo: No such file or directory hello The 'foo' is a resursively expanded (i.e. lazily expanded) variable. GNU Make 4.3 expands 'foo' just before running the recipe '@echo $(foo)', at this point, the directory 'bar' exists. GNU Make 4.4 expands 'foo' to evaluate $(shell mkdir bar) because it is exported. At this point, the directory 'bar' does not exit yet. The cat command cannot resolve the bar/../foo path, hence the error message. Let's get back to the kernel Makefile. In arch/arm/boot/compressed/Makefile, KBSS_SZ is referenced by LDFLAGS_vmlinux, which is recursive and also exported by the top Makefile. GNU Make 4.3 expands KBSS_SZ just before running the recipes, so no error message. GNU Make 4.4 expands KBSS_SZ in the parse stage, where the directory arm/arm/boot/compressed does not exit yet. When compiled with O=, the output directory is created by $(shell mkdir -p $(obj-dirs)) in scripts/Makefile.build. There are two ways to fix this particular issue: - change "$(obj)/../../../../vmlinux" in KBSS_SZ to "vmlinux" - unexport LDFLAGS_vmlinux This commit takes the latter course because it is what I originally intended. Commit 3ec8a5b33dea ("kbuild: do not export LDFLAGS_vmlinux") unexported LDFLAGS_vmlinux. Commit 5d4aeffbf709 ("kbuild: rebuild .vmlinux.export.o when its prerequisite is updated") accidentally exported it again. We can clean up arch/arm/boot/compressed/Makefile later. [1]: https://git.savannah.gnu.org/cgit/make.git/commit/?id=98da874c43035a490cdca81331724f233a3d0c9a Link: https://lore.kernel.org/all/Y7i8+EjwdnhHtlrr@dev-arch.thelio-3990X/ Fixes: 5d4aeffbf709 ("kbuild: rebuild .vmlinux.export.o when its prerequisite is updated") Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2023-01-08 19:23:17 +00:00
LDFLAGS_vmlinux =
# Use USERINCLUDE when you must reference the UAPI directories only.
USERINCLUDE := \
-I$(srctree)/arch/$(SRCARCH)/include/uapi \
-I$(objtree)/arch/$(SRCARCH)/include/generated/uapi \
-I$(srctree)/include/uapi \
-I$(objtree)/include/generated/uapi \
-include $(srctree)/include/linux/compiler-version.h \
-include $(srctree)/include/linux/kconfig.h
# Use LINUXINCLUDE when you must reference the include/ directory.
# Needed to be compatible with the O= option
LINUXINCLUDE := \
-I$(srctree)/arch/$(SRCARCH)/include \
-I$(objtree)/arch/$(SRCARCH)/include/generated \
$(if $(building_out_of_srctree),-I$(srctree)/include) \
-I$(objtree)/include \
$(USERINCLUDE)
KBUILD_AFLAGS := -D__ASSEMBLY__ -fno-PIE
KBUILD_CFLAGS :=
KBUILD_CFLAGS += -std=gnu11
KBUILD_CFLAGS += -fshort-wchar
KBUILD_CFLAGS += -funsigned-char
KBUILD_CFLAGS += -fno-common
KBUILD_CFLAGS += -fno-PIE
KBUILD_CFLAGS += -fno-strict-aliasing
KBUILD_CPPFLAGS := -D__KERNEL__
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS := $(rust_common_flags) \
-Cpanic=abort -Cembed-bitcode=n -Clto=n \
-Cforce-unwind-tables=n -Ccodegen-units=1 \
-Csymbol-mangling-version=v0 \
-Crelocation-model=static \
-Zfunction-sections=n \
-Dclippy::float_arithmetic
KBUILD_AFLAGS_KERNEL :=
KBUILD_CFLAGS_KERNEL :=
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS_KERNEL :=
kbuild: allow assignment to {A,C,LD}FLAGS_MODULE on the command line It is now possible to assign options to AS, CC and LD on the command line - which is only used when building modules. {A,C,LD}FLAGS_MODULE was all used both in the top-level Makefile in the arch makefiles, thus users had no way to specify additional options to AS, CC, LD when building modules without overriding the original value. Introduce a new set of variables KBUILD_{A,C,LD}FLAGS_MODULE that is used by arch specific files and free up {A,C,LD}FLAGS_MODULE so they can be assigned on the command line. All arch Makefiles that used the old variables has been updated. Note: Previously we had a MODFLAGS variable for both AS and CC. But in favour of consistency this was dropped. So in some cases arch Makefile has one assignmnet replaced by two assignmnets. Note2: MODFLAGS was not documented and is dropped without any notice. I do not expect much/any breakage from this. Signed-off-by: Sam Ravnborg <sam@ravnborg.org> Cc: Denys Vlasenko <vda.linux@googlemail.com> Cc: Haavard Skinnemoen <hskinnemoen@atmel.com> Cc: Mike Frysinger <vapier@gentoo.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Acked-by: Mike Frysinger <vapier@gentoo.org> [blackfin] Acked-by: Haavard Skinnemoen <haavard.skinnemoen@atmel.com> [avr32] Signed-off-by: Michal Marek <mmarek@suse.cz>
2010-07-28 15:33:09 +00:00
KBUILD_AFLAGS_MODULE := -DMODULE
KBUILD_CFLAGS_MODULE := -DMODULE
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS_MODULE := --cfg MODULE
KBUILD_LDFLAGS_MODULE :=
KBUILD_LDFLAGS :=
CLANG_FLAGS :=
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
ifeq ($(KBUILD_CLIPPY),1)
RUSTC_OR_CLIPPY_QUIET := CLIPPY
RUSTC_OR_CLIPPY = $(CLIPPY_DRIVER)
else
RUSTC_OR_CLIPPY_QUIET := RUSTC
RUSTC_OR_CLIPPY = $(RUSTC)
endif
ifdef RUST_LIB_SRC
export RUST_LIB_SRC
endif
# Allows the usage of unstable features in stable compilers.
export RUSTC_BOOTSTRAP := 1
export ARCH SRCARCH CONFIG_SHELL BASH HOSTCC KBUILD_HOSTCFLAGS CROSS_COMPILE LD CC HOSTPKG_CONFIG
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
export RUSTC RUSTDOC RUSTFMT RUSTC_OR_CLIPPY_QUIET RUSTC_OR_CLIPPY BINDGEN CARGO
export HOSTRUSTC KBUILD_HOSTRUSTFLAGS
export CPP AR NM STRIP OBJCOPY OBJDUMP READELF PAHOLE RESOLVE_BTFIDS LEX YACC AWK INSTALLKERNEL
export PERL PYTHON3 CHECK CHECKFLAGS MAKE UTS_MACHINE HOSTCXX
export KGZIP KBZIP2 KLZOP LZMA LZ4 XZ ZSTD
export KBUILD_HOSTCXXFLAGS KBUILD_HOSTLDFLAGS KBUILD_HOSTLDLIBS LDFLAGS_MODULE
export KBUILD_USERCFLAGS KBUILD_USERLDFLAGS
export KBUILD_CPPFLAGS NOSTDINC_FLAGS LINUXINCLUDE OBJCOPYFLAGS KBUILD_LDFLAGS
export KBUILD_CFLAGS CFLAGS_KERNEL CFLAGS_MODULE
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
export KBUILD_RUSTFLAGS RUSTFLAGS_KERNEL RUSTFLAGS_MODULE
export KBUILD_AFLAGS AFLAGS_KERNEL AFLAGS_MODULE
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
export KBUILD_AFLAGS_MODULE KBUILD_CFLAGS_MODULE KBUILD_RUSTFLAGS_MODULE KBUILD_LDFLAGS_MODULE
export KBUILD_AFLAGS_KERNEL KBUILD_CFLAGS_KERNEL KBUILD_RUSTFLAGS_KERNEL
# Files to ignore in find ... statements
export RCS_FIND_IGNORE := \( -name SCCS -o -name BitKeeper -o -name .svn -o \
-name CVS -o -name .pc -o -name .hg -o -name .git \) \
-prune -o
# ===========================================================================
# Rules shared between *config targets and build targets
# Basic helpers built in scripts/basic/
PHONY += scripts_basic
scripts_basic:
$(Q)$(MAKE) $(build)=scripts/basic
PHONY += outputmakefile
ifdef building_out_of_srctree
# Before starting out-of-tree build, make sure the source tree is clean.
# outputmakefile generates a Makefile in the output directory, if using a
# separate output directory. This allows convenient use of make in the
# output directory.
# At the same time when output Makefile generated, generate .gitignore to
# ignore whole output directory
quiet_cmd_makefile = GEN Makefile
cmd_makefile = { \
echo "\# Automatically generated by $(srctree)/Makefile: don't edit"; \
echo "include $(srctree)/Makefile"; \
} > Makefile
outputmakefile:
@if [ -f $(srctree)/.config -o \
-d $(srctree)/include/config -o \
-d $(srctree)/arch/$(SRCARCH)/include/generated ]; then \
echo >&2 "***"; \
echo >&2 "*** The source tree is not clean, please run 'make$(if $(findstring command line, $(origin ARCH)), ARCH=$(ARCH)) mrproper'"; \
echo >&2 "*** in $(abs_srctree)";\
echo >&2 "***"; \
false; \
fi
$(Q)ln -fsn $(srctree) source
$(call cmd,makefile)
$(Q)test -e .gitignore || \
{ echo "# this is build directory, ignore it"; echo "*"; } > .gitignore
endif
# The expansion should be delayed until arch/$(SRCARCH)/Makefile is included.
# Some architectures define CROSS_COMPILE in arch/$(SRCARCH)/Makefile.
# CC_VERSION_TEXT is referenced from Kconfig (so it needs export),
# and from include/config/auto.conf.cmd to detect the compiler upgrade.
kbuild: warn if a different compiler is used for external module builds It is always safe to use the same compiler for the kernel and external modules, but in reality, some distributions such as Fedora release a different version of GCC from the one used for building the kernel. There was a long discussion about mixing different compilers [1]. I do not repeat it here, but at least, showing a heads up in that case is better than nothing. Linus suggested [2]: And a warning might be more palatable even if different compiler version work fine together. Just a heads up on "it looks like you might be mixing compiler versions" is a valid note, and isn't necessarily wrong. Even when they work well together, maybe you want to have people at least _aware_ of it. This commit shows a warning unless the compiler is exactly the same. warning: the compiler differs from the one used to build the kernel The kernel was built by: gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3) You are using: gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1) Check the difference, and if it is OK with you, please proceed at your risk. To avoid the locale issue as in commit bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale"), pass LC_ALL=C to "$(CC) --version". [1] https://lore.kernel.org/linux-hardening/efe6b039a544da8215d5e54aa7c4b6d1986fc2b0.1611607264.git.jpoimboe@redhat.com/ [2] https://lore.kernel.org/lkml/CAHk-=wgjwhDy-y4mQh34L+2aF=n6BjzHdqAW2=8wri5x7O04pA@mail.gmail.com/ Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-01 02:53:46 +00:00
CC_VERSION_TEXT = $(subst $(pound),,$(shell LC_ALL=C $(CC) --version 2>/dev/null | head -n 1))
ifneq ($(findstring clang,$(CC_VERSION_TEXT)),)
include $(srctree)/scripts/Makefile.clang
endif
# Include this also for config targets because some architectures need
# cc-cross-prefix to determine CROSS_COMPILE.
ifdef need-compiler
include $(srctree)/scripts/Makefile.compiler
endif
ifdef config-build
# ===========================================================================
# *config targets only - make sure prerequisites are updated, and descend
# in scripts/kconfig to make the *config target
# Read arch-specific Makefile to set KBUILD_DEFCONFIG as needed.
# KBUILD_DEFCONFIG may point out an alternative default configuration
# used for 'make defconfig'
include $(srctree)/arch/$(SRCARCH)/Makefile
kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE Commit 21c54b774744 ("kconfig: show compiler version text in the top comment") was intended to detect the compiler upgrade, but Geert reported a breakage on the m68k build. The compiler upgrade is detected by the change of the environment variable, CC_VERSION_TEXT, which contains the first line of the output from $(CC) --version. Currently, this works well when CROSS_COMPILE is given via the environment variable or the Make command line. However, some architectures such as m68k can specify CROSS_COMPILE from arch/$(SRCARCH)/Makefile as well. In this case, "make ARCH=m68k" ends up with endless syncconfig loop. $ make ARCH=m68k defconfig *** Default configuration is based on 'multi_defconfig' # # configuration written to .config # $ make ARCH=m68k scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig Things are happening like this: Because arch/$(SRCARCH)/Makefile is included after CC_VERSION_TEXT is set, it contains the host compiler version in the defconfig phase. To create or update auto.conf, the following line is triggered: include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig This recurses the top Makefile after arch/$(SRCARCH)/Makefile is included. CROSS_COMPILE is set to a m68k toolchain prefix and exported to the recursed Make. Then, syncconfig is invoked with the target compiler version in CC_VERSION_TEXT. The Make will restart because auto.conf and auto.conf.cmd have been updated. At this point, CROSS_COMPILE is reset, so CC_VERSION_TEXT is set to the host compiler version again. Then, syncconfig is triggered due to the change of CC_VERSION_TEXT. This loop continues eternally. To fix this problem, $(CC_VERSION_TEXT) must be evaluated only after arch/$(SRCARCH)/Makefile. Setting it earlier is OK as long as it is defined by using the '=' operator instead of ':='. For the defconfig phase, $(CC_VERSION_TEXT) is evaluated when Kbuild descends into scripts/kconfig/, so it contains the target compiler version correctly. include/config/auto.conf.cmd references $(CC_VERSION_TEXT) as well, so it must be included after arch/$(SRCARCH)/Makefile. Fixes: 21c54b774744 ("kconfig: show compiler version text in the top comment") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
2018-06-08 00:21:43 +00:00
export KBUILD_DEFCONFIG KBUILD_KCONFIG CC_VERSION_TEXT
config: outputmakefile scripts_basic FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
%config: outputmakefile scripts_basic FORCE
$(Q)$(MAKE) $(build)=scripts/kconfig $@
else #!config-build
# ===========================================================================
# Build targets only - this includes vmlinux, arch-specific targets, clean
# targets and others. In general all targets except *config targets.
# If building an external module we do not care about the all: rule
# but instead __all depend on modules
PHONY += all
ifeq ($(KBUILD_EXTMOD),)
__all: all
else
__all: modules
endif
targets :=
# Decide whether to build built-in, modular, or both.
# Normally, just do built-in.
KBUILD_MODULES :=
KBUILD_BUILTIN := 1
# If we have only "make modules", don't compile built-in objects.
ifeq ($(MAKECMDGOALS),modules)
KBUILD_BUILTIN :=
endif
# If we have "make <whatever> modules", compile modules
# in addition to whatever we do anyway.
# Just "make" or "make all" shall build modules as well
Makefile: Add clang-tidy and static analyzer support to makefile This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-22 14:56:18 +00:00
ifneq ($(filter all modules nsdeps %compile_commands.json clang-%,$(MAKECMDGOALS)),)
KBUILD_MODULES := 1
endif
ifeq ($(MAKECMDGOALS),)
KBUILD_MODULES := 1
endif
export KBUILD_MODULES KBUILD_BUILTIN
ifdef need-config
include include/config/auto.conf
endif
ifeq ($(KBUILD_EXTMOD),)
# Objects we will link into vmlinux / subdirs we need to visit
core-y :=
drivers-y :=
libs-y := lib/
endif # KBUILD_EXTMOD
kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE Commit 21c54b774744 ("kconfig: show compiler version text in the top comment") was intended to detect the compiler upgrade, but Geert reported a breakage on the m68k build. The compiler upgrade is detected by the change of the environment variable, CC_VERSION_TEXT, which contains the first line of the output from $(CC) --version. Currently, this works well when CROSS_COMPILE is given via the environment variable or the Make command line. However, some architectures such as m68k can specify CROSS_COMPILE from arch/$(SRCARCH)/Makefile as well. In this case, "make ARCH=m68k" ends up with endless syncconfig loop. $ make ARCH=m68k defconfig *** Default configuration is based on 'multi_defconfig' # # configuration written to .config # $ make ARCH=m68k scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig Things are happening like this: Because arch/$(SRCARCH)/Makefile is included after CC_VERSION_TEXT is set, it contains the host compiler version in the defconfig phase. To create or update auto.conf, the following line is triggered: include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig This recurses the top Makefile after arch/$(SRCARCH)/Makefile is included. CROSS_COMPILE is set to a m68k toolchain prefix and exported to the recursed Make. Then, syncconfig is invoked with the target compiler version in CC_VERSION_TEXT. The Make will restart because auto.conf and auto.conf.cmd have been updated. At this point, CROSS_COMPILE is reset, so CC_VERSION_TEXT is set to the host compiler version again. Then, syncconfig is triggered due to the change of CC_VERSION_TEXT. This loop continues eternally. To fix this problem, $(CC_VERSION_TEXT) must be evaluated only after arch/$(SRCARCH)/Makefile. Setting it earlier is OK as long as it is defined by using the '=' operator instead of ':='. For the defconfig phase, $(CC_VERSION_TEXT) is evaluated when Kbuild descends into scripts/kconfig/, so it contains the target compiler version correctly. include/config/auto.conf.cmd references $(CC_VERSION_TEXT) as well, so it must be included after arch/$(SRCARCH)/Makefile. Fixes: 21c54b774744 ("kconfig: show compiler version text in the top comment") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
2018-06-08 00:21:43 +00:00
# The all: target is the default when no target is given on the
# command line.
# This allow a user to issue only 'make' to build a kernel including modules
# Defaults to vmlinux, but the arch makefile usually adds further targets
all: vmlinux
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
CFLAGS_GCOV := -fprofile-arcs -ftest-coverage
ifdef CONFIG_CC_IS_GCC
CFLAGS_GCOV += -fno-tree-loop-im
endif
export CFLAGS_GCOV
kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE Commit 21c54b774744 ("kconfig: show compiler version text in the top comment") was intended to detect the compiler upgrade, but Geert reported a breakage on the m68k build. The compiler upgrade is detected by the change of the environment variable, CC_VERSION_TEXT, which contains the first line of the output from $(CC) --version. Currently, this works well when CROSS_COMPILE is given via the environment variable or the Make command line. However, some architectures such as m68k can specify CROSS_COMPILE from arch/$(SRCARCH)/Makefile as well. In this case, "make ARCH=m68k" ends up with endless syncconfig loop. $ make ARCH=m68k defconfig *** Default configuration is based on 'multi_defconfig' # # configuration written to .config # $ make ARCH=m68k scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig Things are happening like this: Because arch/$(SRCARCH)/Makefile is included after CC_VERSION_TEXT is set, it contains the host compiler version in the defconfig phase. To create or update auto.conf, the following line is triggered: include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig This recurses the top Makefile after arch/$(SRCARCH)/Makefile is included. CROSS_COMPILE is set to a m68k toolchain prefix and exported to the recursed Make. Then, syncconfig is invoked with the target compiler version in CC_VERSION_TEXT. The Make will restart because auto.conf and auto.conf.cmd have been updated. At this point, CROSS_COMPILE is reset, so CC_VERSION_TEXT is set to the host compiler version again. Then, syncconfig is triggered due to the change of CC_VERSION_TEXT. This loop continues eternally. To fix this problem, $(CC_VERSION_TEXT) must be evaluated only after arch/$(SRCARCH)/Makefile. Setting it earlier is OK as long as it is defined by using the '=' operator instead of ':='. For the defconfig phase, $(CC_VERSION_TEXT) is evaluated when Kbuild descends into scripts/kconfig/, so it contains the target compiler version correctly. include/config/auto.conf.cmd references $(CC_VERSION_TEXT) as well, so it must be included after arch/$(SRCARCH)/Makefile. Fixes: 21c54b774744 ("kconfig: show compiler version text in the top comment") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
2018-06-08 00:21:43 +00:00
tracing/Makefile: Fix handling redefinition of CC_FLAGS_FTRACE As a Kernel developer, I make heavy use of "make targz-pkg" in order to locally compile and remotely install my development Kernels. The nice feature I rely on is that after a normal "make", "make targz-pkg" only generates the tarball without having to recompile everything. That was true until commit f28bc3c32c05 ("tracing: Handle CC_FLAGS_FTRACE more accurately"). After it, running "make targz-pkg" after "make" will recompile the whole Kernel tree, making my development workflow much slower. The Kernel is choosing to recompile everything because it claims the command line has changed. A diff of the .cmd files show a repeated -mfentry in one of the files. That is because "make targz-pkg" calls "make modules_install" and the environment is already populated with the exported variables, CC_FLAGS_FTRACE being one of them. Then, -mfentry gets duplicated because it is not protected behind an ifndef block, like -pg. To complicate the problem a little bit more, architectures can define their own version CC_FLAGS_FTRACE, so our code not only has to consider recursive Makefiles, but also architecture overrides. So in this patch we move CC_FLAGS_FTRACE up and unconditionally define it to -pg. Then we let the architecture Makefiles possibly override it, and finally append the extra options later. This ensures the variable is always fully redefined at each invocation so recursive Makefiles don't keep appending, and hopefully it maintains the intended behavior on how architectures can override the defaults.. Thanks Steven Rostedt and Vasily Gorbik for the help on this regression. Cc: Michal Marek <michal.lkml@markovi.net> Cc: Ingo Molnar <mingo@redhat.com> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Cc: linux-kbuild@vger.kernel.org Fixes: commit f28bc3c32c05 ("tracing: Handle CC_FLAGS_FTRACE more accurately") Acked-by: Vasily Gorbik <gor@linux.ibm.com> Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
2018-09-10 17:59:56 +00:00
# The arch Makefiles can override CC_FLAGS_FTRACE. We may also append it later.
ifdef CONFIG_FUNCTION_TRACER
CC_FLAGS_FTRACE := -pg
endif
include $(srctree)/arch/$(SRCARCH)/Makefile
ifdef need-config
ifdef may-sync-config
kbuild: fix endless syncconfig in case arch Makefile sets CROSS_COMPILE Commit 21c54b774744 ("kconfig: show compiler version text in the top comment") was intended to detect the compiler upgrade, but Geert reported a breakage on the m68k build. The compiler upgrade is detected by the change of the environment variable, CC_VERSION_TEXT, which contains the first line of the output from $(CC) --version. Currently, this works well when CROSS_COMPILE is given via the environment variable or the Make command line. However, some architectures such as m68k can specify CROSS_COMPILE from arch/$(SRCARCH)/Makefile as well. In this case, "make ARCH=m68k" ends up with endless syncconfig loop. $ make ARCH=m68k defconfig *** Default configuration is based on 'multi_defconfig' # # configuration written to .config # $ make ARCH=m68k scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig scripts/kconfig/conf --syncconfig Kconfig Things are happening like this: Because arch/$(SRCARCH)/Makefile is included after CC_VERSION_TEXT is set, it contains the host compiler version in the defconfig phase. To create or update auto.conf, the following line is triggered: include/config/%.conf: $(KCONFIG_CONFIG) include/config/auto.conf.cmd $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig This recurses the top Makefile after arch/$(SRCARCH)/Makefile is included. CROSS_COMPILE is set to a m68k toolchain prefix and exported to the recursed Make. Then, syncconfig is invoked with the target compiler version in CC_VERSION_TEXT. The Make will restart because auto.conf and auto.conf.cmd have been updated. At this point, CROSS_COMPILE is reset, so CC_VERSION_TEXT is set to the host compiler version again. Then, syncconfig is triggered due to the change of CC_VERSION_TEXT. This loop continues eternally. To fix this problem, $(CC_VERSION_TEXT) must be evaluated only after arch/$(SRCARCH)/Makefile. Setting it earlier is OK as long as it is defined by using the '=' operator instead of ':='. For the defconfig phase, $(CC_VERSION_TEXT) is evaluated when Kbuild descends into scripts/kconfig/, so it contains the target compiler version correctly. include/config/auto.conf.cmd references $(CC_VERSION_TEXT) as well, so it must be included after arch/$(SRCARCH)/Makefile. Fixes: 21c54b774744 ("kconfig: show compiler version text in the top comment") Reported-by: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Tested-by: Geert Uytterhoeven <geert@linux-m68k.org>
2018-06-08 00:21:43 +00:00
# Read in dependencies to all Kconfig* files, make sure to run syncconfig if
# changes are detected. This should be included after arch/$(SRCARCH)/Makefile
# because some architectures define CROSS_COMPILE there.
kbuild: turn auto.conf.cmd into a mandatory include file syncconfig is responsible for keeping auto.conf up-to-date, so if it fails for any reason, the build must be terminated immediately. However, since commit 9390dff66a52 ("kbuild: invoke syncconfig if include/config/auto.conf.cmd is missing"), Kbuild continues running even after syncconfig fails. You can confirm this by intentionally making syncconfig error out: diff --git a/scripts/kconfig/confdata.c b/scripts/kconfig/confdata.c index 08ba146..307b9de 100644 --- a/scripts/kconfig/confdata.c +++ b/scripts/kconfig/confdata.c @@ -1023,6 +1023,9 @@ int conf_write_autoconf(int overwrite) FILE *out, *tristate, *out_h; int i; + if (overwrite) + return 1; + if (!overwrite && is_present(autoconf_name)) return 0; Then, syncconfig fails, but Make would not stop: $ make -s mrproper allyesconfig defconfig $ make scripts/kconfig/conf --syncconfig Kconfig *** Error during sync of the configuration. make[2]: *** [scripts/kconfig/Makefile;69: syncconfig] Error 1 make[1]: *** [Makefile;557: syncconfig] Error 2 make: *** [include/config/auto.conf.cmd] Deleting file 'include/config/tristate.conf' make: Failed to remake makefile 'include/config/auto.conf'. SYSTBL arch/x86/include/generated/asm/syscalls_32.h SYSHDR arch/x86/include/generated/asm/unistd_32_ia32.h SYSHDR arch/x86/include/generated/asm/unistd_64_x32.h SYSTBL arch/x86/include/generated/asm/syscalls_64.h [ continue running ... ] The reason is in the behavior of a pattern rule with multi-targets. %/auto.conf %/auto.conf.cmd %/tristate.conf: $(KCONFIG_CONFIG) $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig GNU Make knows this rule is responsible for making all the three files simultaneously. As far as examined, auto.conf.cmd is the target in question when this rule is invoked. It is probably because auto.conf.cmd is included below the inclusion of auto.conf. The inclusion of auto.conf is mandatory, while that of auto.conf.cmd is optional. GNU Make does not care about the failure in the process of updating optional include files. I filed this issue (https://savannah.gnu.org/bugs/?56301) in case this behavior could be improved somehow in future releases of GNU Make. Anyway, it is quite easy to fix our Makefile. Given that auto.conf is already a mandatory include file, there is no reason to stick auto.conf.cmd optional. Make it mandatory as well. Cc: linux-stable <stable@vger.kernel.org> # 5.0+ Fixes: 9390dff66a52 ("kbuild: invoke syncconfig if include/config/auto.conf.cmd is missing") Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-05-12 02:13:48 +00:00
include include/config/auto.conf.cmd
$(KCONFIG_CONFIG):
@echo >&2 '***'
@echo >&2 '*** Configuration file "$@" not found!'
@echo >&2 '***'
@echo >&2 '*** Please run some configurator (e.g. "make oldconfig" or'
@echo >&2 '*** "make menuconfig" or "make xconfig").'
@echo >&2 '***'
@/bin/false
2018-02-13 07:58:20 +00:00
# The actual configuration files used during the build are stored in
# include/generated/ and include/config/. Update them if .config is newer than
# include/config/auto.conf (which mirrors .config).
kbuild: invoke syncconfig if include/config/auto.conf.cmd is missing If include/config/auto.conf.cmd is lost for some reasons, it is not self-healing, so the top Makefile misses to run syncconfig. Move include/config/auto.conf.cmd to the target side. I used a pattern rule instead of a normal rule here although it is a bit gross. If the rule were written with a normal rule like this, include/config/auto.conf \ include/config/auto.conf.cmd \ include/config/tristate.conf: $(KCONFIG_CONFIG) $(Q)$(MAKE) -f $(srctree)/Makefile syncconfig ... syncconfig would be executed per target. Using a pattern rule makes sure that syncconfig is executed just once because Make assumes the recipe will create all of the targets. Here is a quote from the GNU Make manual [1]: "Pattern rules may have more than one target. Unlike normal rules, this does not act as many different rules with the same prerequisites and recipe. If a pattern rule has multiple targets, make knows that the rule's recipe is responsible for making all of the targets. The recipe is executed only once to make all the targets. When searching for a pattern rule to match a target, the target patterns of a rule other than the one that matches the target in need of a rule are incidental: make worries only about giving a recipe and prerequisites to the file presently in question. However, when this file's recipe is run, the other targets are marked as having been updated themselves." [1]: https://www.gnu.org/software/make/manual/html_node/Pattern-Intro.html Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-02-22 07:40:10 +00:00
#
# This exploits the 'multi-target pattern rule' trick.
# The syncconfig should be executed only once to make all the targets.
# (Note: use the grouped target '&:' when we bump to GNU Make 4.3)
#
# Do not use $(call cmd,...) here. That would suppress prompts from syncconfig,
# so you cannot notice that Kconfig is waiting for the user input.
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
%/config/auto.conf %/config/auto.conf.cmd %/generated/autoconf.h %/generated/rustc_cfg: $(KCONFIG_CONFIG)
$(Q)$(kecho) " SYNC $@"
$(Q)$(MAKE) -f $(srctree)/Makefile syncconfig
else # !may-sync-config
kbuild: do not update config when running install targets "make syncconfig" is automatically invoked when any of the following happens: - .config is updated - any of Kconfig files is updated - any of environment variables referenced in Kconfig is changed Then, it updates configuration files such as include/config/auto.conf include/generated/autoconf.h, etc. Even install targets (install, modules_install, etc.) are no exception. However, they should never ever modify the source tree. Install targets are often run with root privileges. Once those configuration files are owned by root, "make mrproper" would end up with permission error. Install targets should just copy things blindly. They should not care whether the configuration is up-to-date or not. This makes more sense because we are interested in the configuration that was used in the previous kernel building. This issue has existed since before, but rarely happened. I expect more chance where people are hit by this; with the new Kconfig syntax extension, the .config now contains the compiler information. If you cross-compile the kernel with CROSS_COMPILE, but forget to pass it for "make install", you meet "any of environment variables referenced in Kconfig is changed" because $(CC) is referenced in Kconfig. Another scenario is the compiler upgrade before the installation. Install targets need the configuration. "make modules_install" refer to CONFIG_MODULES etc. "make dtbs_install" also needs CONFIG_ARCH_* to decide which dtb files to install. However, the auto-update of the configuration files should be avoided. We already do this for external modules. Now, Make targets are categorized into 3 groups: [1] Do not need the kernel configuration at all help, coccicheck, headers_install etc. [2] Need the latest kernel configuration If new config options are added, Kconfig will show prompt to ask user's selection. Build targets such as vmlinux, in-kernel modules are the cases. [3] Need the kernel configuration, but do not want to update it Install targets except headers_install, and external modules are the cases. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 07:46:34 +00:00
# External modules and some install targets need include/generated/autoconf.h
# and include/config/auto.conf but do not care if they are up-to-date.
# Use auto.conf to trigger the test
PHONY += include/config/auto.conf
include/config/auto.conf:
@test -e include/generated/autoconf.h -a -e $@ || ( \
echo >&2; \
echo >&2 " ERROR: Kernel configuration is invalid."; \
echo >&2 " include/generated/autoconf.h or $@ are missing.";\
echo >&2 " Run 'make oldconfig && make prepare' on kernel src to fix it."; \
echo >&2 ; \
/bin/false)
kbuild: do not update config when running install targets "make syncconfig" is automatically invoked when any of the following happens: - .config is updated - any of Kconfig files is updated - any of environment variables referenced in Kconfig is changed Then, it updates configuration files such as include/config/auto.conf include/generated/autoconf.h, etc. Even install targets (install, modules_install, etc.) are no exception. However, they should never ever modify the source tree. Install targets are often run with root privileges. Once those configuration files are owned by root, "make mrproper" would end up with permission error. Install targets should just copy things blindly. They should not care whether the configuration is up-to-date or not. This makes more sense because we are interested in the configuration that was used in the previous kernel building. This issue has existed since before, but rarely happened. I expect more chance where people are hit by this; with the new Kconfig syntax extension, the .config now contains the compiler information. If you cross-compile the kernel with CROSS_COMPILE, but forget to pass it for "make install", you meet "any of environment variables referenced in Kconfig is changed" because $(CC) is referenced in Kconfig. Another scenario is the compiler upgrade before the installation. Install targets need the configuration. "make modules_install" refer to CONFIG_MODULES etc. "make dtbs_install" also needs CONFIG_ARCH_* to decide which dtb files to install. However, the auto-update of the configuration files should be avoided. We already do this for external modules. Now, Make targets are categorized into 3 groups: [1] Do not need the kernel configuration at all help, coccicheck, headers_install etc. [2] Need the latest kernel configuration If new config options are added, Kconfig will show prompt to ask user's selection. Build targets such as vmlinux, in-kernel modules are the cases. [3] Need the kernel configuration, but do not want to update it Install targets except headers_install, and external modules are the cases. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-20 07:46:34 +00:00
endif # may-sync-config
endif # need-config
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
KBUILD_CFLAGS += -fno-delete-null-pointer-checks
ifdef CONFIG_CC_OPTIMIZE_FOR_PERFORMANCE
KBUILD_CFLAGS += -O2
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS += -Copt-level=2
else ifdef CONFIG_CC_OPTIMIZE_FOR_SIZE
KBUILD_CFLAGS += -Os
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS += -Copt-level=s
endif
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# Always set `debug-assertions` and `overflow-checks` because their default
# depends on `opt-level` and `debug-assertions`, respectively.
KBUILD_RUSTFLAGS += -Cdebug-assertions=$(if $(CONFIG_RUST_DEBUG_ASSERTIONS),y,n)
KBUILD_RUSTFLAGS += -Coverflow-checks=$(if $(CONFIG_RUST_OVERFLOW_CHECKS),y,n)
./Makefile: tell gcc optimizer to never introduce new data races We have been chasing a memory corruption bug, which turned out to be caused by very old gcc (4.3.4), which happily turned conditional load into a non-conditional one, and that broke correctness (the condition was met only if lock was held) and corrupted memory. This particular problem with that particular code did not happen when never gccs were used. I've brought this up with our gcc folks, as I wanted to make sure that this can't really happen again, and it turns out it actually can. Quoting Martin Jambor <mjambor@suse.cz>: "More current GCCs are more careful when it comes to replacing a conditional load with a non-conditional one, most notably they check that a store happens in each iteration of _a_ loop but they assume loops are executed. They also perform a simple check whether the store cannot trap which currently passes only for non-const variables. A simple testcase demonstrating it on an x86_64 is for example the following: $ cat cond_store.c int g_1 = 1; int g_2[1024] __attribute__((section ("safe_section"), aligned (4096))); int c = 4; int __attribute__ ((noinline)) foo (void) { int l; for (l = 0; (l != 4); l++) { if (g_1) return l; for (g_2[0] = 0; (g_2[0] >= 26); ++g_2[0]) ; } return 2; } int main (int argc, char* argv[]) { if (mprotect (g_2, sizeof(g_2), PROT_READ) == -1) { int e = errno; error (e, e, "mprotect error %i", e); } foo (); __builtin_printf("OK\n"); return 0; } /* EOF */ $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=0 $ ./a.out OK $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=1 $ ./a.out Segmentation fault The testcase fails the same at least with 4.9, 4.8 and 4.7. Therefore I would suggest building kernels with this parameter set to zero. I also agree with Jikos that the default should be changed for -O2. I have run most of the SPEC 2k6 CPU benchmarks (gamess and dealII failed, at -O2, not sure why) compiled with and without this option and did not see any real difference between respective run-times" Hopefully the default will be changed in newer gccs, but let's force it for kernel builds so that we are on a safe side even when older gcc are used. The code in question was out-of-tree printk-in-NMI (yeah, surprise suprise, once again) patch written by Petr Mladek, let me quote his comment from our internal bugzilla: "I have spent few days investigating inconsistent state of kernel ring buffer. It went out that it was caused by speculative store generated by gcc-4.3.4. The problem is in assembly generated for make_free_space(). The functions is called the following way: + vprintk_emit(); + log = MAIN_LOG; // with logbuf_lock or log = NMI_LOG; // with nmi_logbuf_lock cont_add(log, ...); + cont_flush(log, ...); + log_store(log, ...); + log_make_free_space(log, ...); If called with log = NMI_LOG then only nmi_log_* global variables are safe to modify but the generated code does store also into (main_)log_* global variables: <log_make_free_space>: 55 push %rbp 89 f6 mov %esi,%esi 48 8b 05 03 99 51 01 mov 0x1519903(%rip),%rax # ffffffff82620868 <nmi_log_next_id> 44 8b 1d ec 98 51 01 mov 0x15198ec(%rip),%r11d # ffffffff82620858 <log_next_idx> 8b 35 36 60 14 01 mov 0x1146036(%rip),%esi # ffffffff8224cfa8 <log_buf_len> 44 8b 35 33 60 14 01 mov 0x1146033(%rip),%r14d # ffffffff8224cfac <nmi_log_buf_len> 4c 8b 2d d0 98 51 01 mov 0x15198d0(%rip),%r13 # ffffffff82620850 <log_next_seq> 4c 8b 25 11 61 14 01 mov 0x1146111(%rip),%r12 # ffffffff8224d098 <log_buf> 49 89 c2 mov %rax,%r10 48 21 c2 and %rax,%rdx 48 8b 1d 0c 99 55 01 mov 0x155990c(%rip),%rbx # ffffffff826608a0 <nmi_log_buf> 49 c1 ea 20 shr $0x20,%r10 48 89 55 d0 mov %rdx,-0x30(%rbp) 44 29 de sub %r11d,%esi 45 29 d6 sub %r10d,%r14d 4c 8b 0d 97 98 51 01 mov 0x1519897(%rip),%r9 # ffffffff82620840 <log_first_seq> eb 7e jmp ffffffff81107029 <log_make_free_space+0xe9> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 e8 mov %r13,%rax 4c 89 ca mov %r9,%rdx 74 0a je ffffffff8110703d <log_make_free_space+0xfd> 8b 15 27 98 51 01 mov 0x1519827(%rip),%edx # ffffffff82620860 <nmi_log_first_id> 48 8b 45 d0 mov -0x30(%rbp),%rax 48 39 c2 cmp %rax,%rdx # end of loop 0f 84 da 00 00 00 je ffffffff81107120 <log_make_free_space+0x1e0> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 0d 17 97 51 01 mov %r9,0x1519717(%rip) # ffffffff82620840 <log_first_seq> ^^^^^^^^^^^^^^^^^^^^^^^^^^ KABOOOM 74 35 je ffffffff81107160 <log_make_free_space+0x220> It stores log_first_seq when edi == NMI_LOG. This instructions are used also when edi == MAIN_LOG but the store is done speculatively before the condition is decided. It is unsafe because we do not have "logbuf_lock" in NMI context and some other process migh modify "log_first_seq" in parallel" I believe that the best course of action is both - building kernel (and anything multi-threaded, I guess) with that optimization turned off - persuade gcc folks to change the default for future releases Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Martin Jambor <mjambor@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Marek Polacek <polacek@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Steven Noonan <steven@uplinklabs.net> Cc: Richard Biener <richard.guenther@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 23:08:43 +00:00
# Tell gcc to never replace conditional load with a non-conditional one
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
ifdef CONFIG_CC_IS_GCC
# gcc-10 renamed --param=allow-store-data-races=0 to
# -fno-allow-store-data-races.
./Makefile: tell gcc optimizer to never introduce new data races We have been chasing a memory corruption bug, which turned out to be caused by very old gcc (4.3.4), which happily turned conditional load into a non-conditional one, and that broke correctness (the condition was met only if lock was held) and corrupted memory. This particular problem with that particular code did not happen when never gccs were used. I've brought this up with our gcc folks, as I wanted to make sure that this can't really happen again, and it turns out it actually can. Quoting Martin Jambor <mjambor@suse.cz>: "More current GCCs are more careful when it comes to replacing a conditional load with a non-conditional one, most notably they check that a store happens in each iteration of _a_ loop but they assume loops are executed. They also perform a simple check whether the store cannot trap which currently passes only for non-const variables. A simple testcase demonstrating it on an x86_64 is for example the following: $ cat cond_store.c int g_1 = 1; int g_2[1024] __attribute__((section ("safe_section"), aligned (4096))); int c = 4; int __attribute__ ((noinline)) foo (void) { int l; for (l = 0; (l != 4); l++) { if (g_1) return l; for (g_2[0] = 0; (g_2[0] >= 26); ++g_2[0]) ; } return 2; } int main (int argc, char* argv[]) { if (mprotect (g_2, sizeof(g_2), PROT_READ) == -1) { int e = errno; error (e, e, "mprotect error %i", e); } foo (); __builtin_printf("OK\n"); return 0; } /* EOF */ $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=0 $ ./a.out OK $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=1 $ ./a.out Segmentation fault The testcase fails the same at least with 4.9, 4.8 and 4.7. Therefore I would suggest building kernels with this parameter set to zero. I also agree with Jikos that the default should be changed for -O2. I have run most of the SPEC 2k6 CPU benchmarks (gamess and dealII failed, at -O2, not sure why) compiled with and without this option and did not see any real difference between respective run-times" Hopefully the default will be changed in newer gccs, but let's force it for kernel builds so that we are on a safe side even when older gcc are used. The code in question was out-of-tree printk-in-NMI (yeah, surprise suprise, once again) patch written by Petr Mladek, let me quote his comment from our internal bugzilla: "I have spent few days investigating inconsistent state of kernel ring buffer. It went out that it was caused by speculative store generated by gcc-4.3.4. The problem is in assembly generated for make_free_space(). The functions is called the following way: + vprintk_emit(); + log = MAIN_LOG; // with logbuf_lock or log = NMI_LOG; // with nmi_logbuf_lock cont_add(log, ...); + cont_flush(log, ...); + log_store(log, ...); + log_make_free_space(log, ...); If called with log = NMI_LOG then only nmi_log_* global variables are safe to modify but the generated code does store also into (main_)log_* global variables: <log_make_free_space>: 55 push %rbp 89 f6 mov %esi,%esi 48 8b 05 03 99 51 01 mov 0x1519903(%rip),%rax # ffffffff82620868 <nmi_log_next_id> 44 8b 1d ec 98 51 01 mov 0x15198ec(%rip),%r11d # ffffffff82620858 <log_next_idx> 8b 35 36 60 14 01 mov 0x1146036(%rip),%esi # ffffffff8224cfa8 <log_buf_len> 44 8b 35 33 60 14 01 mov 0x1146033(%rip),%r14d # ffffffff8224cfac <nmi_log_buf_len> 4c 8b 2d d0 98 51 01 mov 0x15198d0(%rip),%r13 # ffffffff82620850 <log_next_seq> 4c 8b 25 11 61 14 01 mov 0x1146111(%rip),%r12 # ffffffff8224d098 <log_buf> 49 89 c2 mov %rax,%r10 48 21 c2 and %rax,%rdx 48 8b 1d 0c 99 55 01 mov 0x155990c(%rip),%rbx # ffffffff826608a0 <nmi_log_buf> 49 c1 ea 20 shr $0x20,%r10 48 89 55 d0 mov %rdx,-0x30(%rbp) 44 29 de sub %r11d,%esi 45 29 d6 sub %r10d,%r14d 4c 8b 0d 97 98 51 01 mov 0x1519897(%rip),%r9 # ffffffff82620840 <log_first_seq> eb 7e jmp ffffffff81107029 <log_make_free_space+0xe9> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 e8 mov %r13,%rax 4c 89 ca mov %r9,%rdx 74 0a je ffffffff8110703d <log_make_free_space+0xfd> 8b 15 27 98 51 01 mov 0x1519827(%rip),%edx # ffffffff82620860 <nmi_log_first_id> 48 8b 45 d0 mov -0x30(%rbp),%rax 48 39 c2 cmp %rax,%rdx # end of loop 0f 84 da 00 00 00 je ffffffff81107120 <log_make_free_space+0x1e0> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 0d 17 97 51 01 mov %r9,0x1519717(%rip) # ffffffff82620840 <log_first_seq> ^^^^^^^^^^^^^^^^^^^^^^^^^^ KABOOOM 74 35 je ffffffff81107160 <log_make_free_space+0x220> It stores log_first_seq when edi == NMI_LOG. This instructions are used also when edi == MAIN_LOG but the store is done speculatively before the condition is decided. It is unsafe because we do not have "logbuf_lock" in NMI context and some other process migh modify "log_first_seq" in parallel" I believe that the best course of action is both - building kernel (and anything multi-threaded, I guess) with that optimization turned off - persuade gcc folks to change the default for future releases Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Martin Jambor <mjambor@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Marek Polacek <polacek@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Steven Noonan <steven@uplinklabs.net> Cc: Richard Biener <richard.guenther@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 23:08:43 +00:00
KBUILD_CFLAGS += $(call cc-option,--param=allow-store-data-races=0)
KBUILD_CFLAGS += $(call cc-option,-fno-allow-store-data-races)
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
endif
./Makefile: tell gcc optimizer to never introduce new data races We have been chasing a memory corruption bug, which turned out to be caused by very old gcc (4.3.4), which happily turned conditional load into a non-conditional one, and that broke correctness (the condition was met only if lock was held) and corrupted memory. This particular problem with that particular code did not happen when never gccs were used. I've brought this up with our gcc folks, as I wanted to make sure that this can't really happen again, and it turns out it actually can. Quoting Martin Jambor <mjambor@suse.cz>: "More current GCCs are more careful when it comes to replacing a conditional load with a non-conditional one, most notably they check that a store happens in each iteration of _a_ loop but they assume loops are executed. They also perform a simple check whether the store cannot trap which currently passes only for non-const variables. A simple testcase demonstrating it on an x86_64 is for example the following: $ cat cond_store.c int g_1 = 1; int g_2[1024] __attribute__((section ("safe_section"), aligned (4096))); int c = 4; int __attribute__ ((noinline)) foo (void) { int l; for (l = 0; (l != 4); l++) { if (g_1) return l; for (g_2[0] = 0; (g_2[0] >= 26); ++g_2[0]) ; } return 2; } int main (int argc, char* argv[]) { if (mprotect (g_2, sizeof(g_2), PROT_READ) == -1) { int e = errno; error (e, e, "mprotect error %i", e); } foo (); __builtin_printf("OK\n"); return 0; } /* EOF */ $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=0 $ ./a.out OK $ ~/gcc/trunk/inst/bin/gcc cond_store.c -O2 --param allow-store-data-races=1 $ ./a.out Segmentation fault The testcase fails the same at least with 4.9, 4.8 and 4.7. Therefore I would suggest building kernels with this parameter set to zero. I also agree with Jikos that the default should be changed for -O2. I have run most of the SPEC 2k6 CPU benchmarks (gamess and dealII failed, at -O2, not sure why) compiled with and without this option and did not see any real difference between respective run-times" Hopefully the default will be changed in newer gccs, but let's force it for kernel builds so that we are on a safe side even when older gcc are used. The code in question was out-of-tree printk-in-NMI (yeah, surprise suprise, once again) patch written by Petr Mladek, let me quote his comment from our internal bugzilla: "I have spent few days investigating inconsistent state of kernel ring buffer. It went out that it was caused by speculative store generated by gcc-4.3.4. The problem is in assembly generated for make_free_space(). The functions is called the following way: + vprintk_emit(); + log = MAIN_LOG; // with logbuf_lock or log = NMI_LOG; // with nmi_logbuf_lock cont_add(log, ...); + cont_flush(log, ...); + log_store(log, ...); + log_make_free_space(log, ...); If called with log = NMI_LOG then only nmi_log_* global variables are safe to modify but the generated code does store also into (main_)log_* global variables: <log_make_free_space>: 55 push %rbp 89 f6 mov %esi,%esi 48 8b 05 03 99 51 01 mov 0x1519903(%rip),%rax # ffffffff82620868 <nmi_log_next_id> 44 8b 1d ec 98 51 01 mov 0x15198ec(%rip),%r11d # ffffffff82620858 <log_next_idx> 8b 35 36 60 14 01 mov 0x1146036(%rip),%esi # ffffffff8224cfa8 <log_buf_len> 44 8b 35 33 60 14 01 mov 0x1146033(%rip),%r14d # ffffffff8224cfac <nmi_log_buf_len> 4c 8b 2d d0 98 51 01 mov 0x15198d0(%rip),%r13 # ffffffff82620850 <log_next_seq> 4c 8b 25 11 61 14 01 mov 0x1146111(%rip),%r12 # ffffffff8224d098 <log_buf> 49 89 c2 mov %rax,%r10 48 21 c2 and %rax,%rdx 48 8b 1d 0c 99 55 01 mov 0x155990c(%rip),%rbx # ffffffff826608a0 <nmi_log_buf> 49 c1 ea 20 shr $0x20,%r10 48 89 55 d0 mov %rdx,-0x30(%rbp) 44 29 de sub %r11d,%esi 45 29 d6 sub %r10d,%r14d 4c 8b 0d 97 98 51 01 mov 0x1519897(%rip),%r9 # ffffffff82620840 <log_first_seq> eb 7e jmp ffffffff81107029 <log_make_free_space+0xe9> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 e8 mov %r13,%rax 4c 89 ca mov %r9,%rdx 74 0a je ffffffff8110703d <log_make_free_space+0xfd> 8b 15 27 98 51 01 mov 0x1519827(%rip),%edx # ffffffff82620860 <nmi_log_first_id> 48 8b 45 d0 mov -0x30(%rbp),%rax 48 39 c2 cmp %rax,%rdx # end of loop 0f 84 da 00 00 00 je ffffffff81107120 <log_make_free_space+0x1e0> [...] 85 ff test %edi,%edi # edi = 1 for NMI_LOG 4c 89 0d 17 97 51 01 mov %r9,0x1519717(%rip) # ffffffff82620840 <log_first_seq> ^^^^^^^^^^^^^^^^^^^^^^^^^^ KABOOOM 74 35 je ffffffff81107160 <log_make_free_space+0x220> It stores log_first_seq when edi == NMI_LOG. This instructions are used also when edi == MAIN_LOG but the store is done speculatively before the condition is decided. It is unsafe because we do not have "logbuf_lock" in NMI context and some other process migh modify "log_first_seq" in parallel" I believe that the best course of action is both - building kernel (and anything multi-threaded, I guess) with that optimization turned off - persuade gcc folks to change the default for future releases Signed-off-by: Jiri Kosina <jkosina@suse.cz> Cc: Martin Jambor <mjambor@suse.cz> Cc: Petr Mladek <pmladek@suse.cz> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Marek Polacek <polacek@redhat.com> Cc: Jakub Jelinek <jakub@redhat.com> Cc: Steven Noonan <steven@uplinklabs.net> Cc: Richard Biener <richard.guenther@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-08-06 23:08:43 +00:00
ifdef CONFIG_READABLE_ASM
# Disable optimizations that make assembler listings hard to read.
# reorder blocks reorders the control in the function
# ipa clone creates specialized cloned functions
# partial inlining inlines only parts of functions
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
KBUILD_CFLAGS += -fno-reorder-blocks -fno-ipa-cp-clone -fno-partial-inlining
endif
stackp-flags-y := -fno-stack-protector
Kbuild: rename CC_STACKPROTECTOR[_STRONG] config variables The changes to automatically test for working stack protector compiler support in the Kconfig files removed the special STACKPROTECTOR_AUTO option that picked the strongest stack protector that the compiler supported. That was all a nice cleanup - it makes no sense to have the AUTO case now that the Kconfig phase can just determine the compiler support directly. HOWEVER. It also meant that doing "make oldconfig" would now _disable_ the strong stackprotector if you had AUTO enabled, because in a legacy config file, the sane stack protector configuration would look like CONFIG_HAVE_CC_STACKPROTECTOR=y # CONFIG_CC_STACKPROTECTOR_NONE is not set # CONFIG_CC_STACKPROTECTOR_REGULAR is not set # CONFIG_CC_STACKPROTECTOR_STRONG is not set CONFIG_CC_STACKPROTECTOR_AUTO=y and when you ran this through "make oldconfig" with the Kbuild changes, it would ask you about the regular CONFIG_CC_STACKPROTECTOR (that had been renamed from CONFIG_CC_STACKPROTECTOR_REGULAR to just CONFIG_CC_STACKPROTECTOR), but it would think that the STRONG version used to be disabled (because it was really enabled by AUTO), and would disable it in the new config, resulting in: CONFIG_HAVE_CC_STACKPROTECTOR=y CONFIG_CC_HAS_STACKPROTECTOR_NONE=y CONFIG_CC_STACKPROTECTOR=y # CONFIG_CC_STACKPROTECTOR_STRONG is not set CONFIG_CC_HAS_SANE_STACKPROTECTOR=y That's dangerously subtle - people could suddenly find themselves with the weaker stack protector setup without even realizing. The solution here is to just rename not just the old RECULAR stack protector option, but also the strong one. This does that by just removing the CC_ prefix entirely for the user choices, because it really is not about the compiler support (the compiler support now instead automatially impacts _visibility_ of the options to users). This results in "make oldconfig" actually asking the user for their choice, so that we don't have any silent subtle security model changes. The end result would generally look like this: CONFIG_HAVE_CC_STACKPROTECTOR=y CONFIG_CC_HAS_STACKPROTECTOR_NONE=y CONFIG_STACKPROTECTOR=y CONFIG_STACKPROTECTOR_STRONG=y CONFIG_CC_HAS_SANE_STACKPROTECTOR=y where the "CC_" versions really are about internal compiler infrastructure, not the user selections. Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-06-14 03:21:18 +00:00
stackp-flags-$(CONFIG_STACKPROTECTOR) := -fstack-protector
stackp-flags-$(CONFIG_STACKPROTECTOR_STRONG) := -fstack-protector-strong
KBUILD_CFLAGS += $(stackp-flags-y)
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS-$(CONFIG_WERROR) += -Dwarnings
KBUILD_RUSTFLAGS += $(KBUILD_RUSTFLAGS-y)
ifdef CONFIG_FRAME_POINTER
KBUILD_CFLAGS += -fno-omit-frame-pointer -fno-optimize-sibling-calls
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS += -Cforce-frame-pointers=y
else
# Some targets (ARM with Thumb2, for example), can't be built with frame
# pointers. For those, we don't have FUNCTION_TRACER automatically
# select FRAME_POINTER. However, FUNCTION_TRACER adds -pg, and this is
# incompatible with -fomit-frame-pointer with current GCC, so we don't use
# -fomit-frame-pointer with FUNCTION_TRACER.
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# In the Rust target specification, "frame-pointer" is set explicitly
# to "may-omit".
ifndef CONFIG_FUNCTION_TRACER
KBUILD_CFLAGS += -fomit-frame-pointer
endif
endif
security: allow using Clang's zero initialization for stack variables In addition to -ftrivial-auto-var-init=pattern (used by CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for locals enabled by -ftrivial-auto-var-init=zero. The future of this flag is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497). Right now it is guarded by another flag, -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang, which means it may not be supported by future Clang releases. Another possible resolution is that -ftrivial-auto-var-init=zero will persist (as certain users have already started depending on it), but the name of the guard flag will change. In the meantime, zero initialization has proven itself as a good production mitigation measure against uninitialized locals. Unlike pattern initialization, which has a higher chance of triggering existing bugs, zero initialization provides safe defaults for strings, pointers, indexes, and sizes. On the other hand, pattern initialization remains safer for return values. Chrome OS and Android are moving to using zero initialization for production builds. Performance-wise, the difference between pattern and zero initialization is usually negligible, although the generated code for zero initialization is more compact. This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that enables zero initialization for locals if the corresponding flags are supported by Clang. Cc: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-16 08:34:35 +00:00
# Initialize all stack variables with a 0xAA pattern.
ifdef CONFIG_INIT_STACK_ALL_PATTERN
KBUILD_CFLAGS += -ftrivial-auto-var-init=pattern
endif
security: allow using Clang's zero initialization for stack variables In addition to -ftrivial-auto-var-init=pattern (used by CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for locals enabled by -ftrivial-auto-var-init=zero. The future of this flag is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497). Right now it is guarded by another flag, -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang, which means it may not be supported by future Clang releases. Another possible resolution is that -ftrivial-auto-var-init=zero will persist (as certain users have already started depending on it), but the name of the guard flag will change. In the meantime, zero initialization has proven itself as a good production mitigation measure against uninitialized locals. Unlike pattern initialization, which has a higher chance of triggering existing bugs, zero initialization provides safe defaults for strings, pointers, indexes, and sizes. On the other hand, pattern initialization remains safer for return values. Chrome OS and Android are moving to using zero initialization for production builds. Performance-wise, the difference between pattern and zero initialization is usually negligible, although the generated code for zero initialization is more compact. This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that enables zero initialization for locals if the corresponding flags are supported by Clang. Cc: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-16 08:34:35 +00:00
# Initialize all stack variables with a zero value.
ifdef CONFIG_INIT_STACK_ALL_ZERO
KBUILD_CFLAGS += -ftrivial-auto-var-init=zero
ifdef CONFIG_CC_HAS_AUTO_VAR_INIT_ZERO_ENABLER
# https://github.com/llvm/llvm-project/issues/44842
CC_AUTO_VAR_INIT_ZERO_ENABLER := -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang
export CC_AUTO_VAR_INIT_ZERO_ENABLER
KBUILD_CFLAGS += $(CC_AUTO_VAR_INIT_ZERO_ENABLER)
security: allow using Clang's zero initialization for stack variables In addition to -ftrivial-auto-var-init=pattern (used by CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for locals enabled by -ftrivial-auto-var-init=zero. The future of this flag is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497). Right now it is guarded by another flag, -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang, which means it may not be supported by future Clang releases. Another possible resolution is that -ftrivial-auto-var-init=zero will persist (as certain users have already started depending on it), but the name of the guard flag will change. In the meantime, zero initialization has proven itself as a good production mitigation measure against uninitialized locals. Unlike pattern initialization, which has a higher chance of triggering existing bugs, zero initialization provides safe defaults for strings, pointers, indexes, and sizes. On the other hand, pattern initialization remains safer for return values. Chrome OS and Android are moving to using zero initialization for production builds. Performance-wise, the difference between pattern and zero initialization is usually negligible, although the generated code for zero initialization is more compact. This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that enables zero initialization for locals if the corresponding flags are supported by Clang. Cc: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-16 08:34:35 +00:00
endif
endif
security: allow using Clang's zero initialization for stack variables In addition to -ftrivial-auto-var-init=pattern (used by CONFIG_INIT_STACK_ALL now) Clang also supports zero initialization for locals enabled by -ftrivial-auto-var-init=zero. The future of this flag is still being debated (see https://bugs.llvm.org/show_bug.cgi?id=45497). Right now it is guarded by another flag, -enable-trivial-auto-var-init-zero-knowing-it-will-be-removed-from-clang, which means it may not be supported by future Clang releases. Another possible resolution is that -ftrivial-auto-var-init=zero will persist (as certain users have already started depending on it), but the name of the guard flag will change. In the meantime, zero initialization has proven itself as a good production mitigation measure against uninitialized locals. Unlike pattern initialization, which has a higher chance of triggering existing bugs, zero initialization provides safe defaults for strings, pointers, indexes, and sizes. On the other hand, pattern initialization remains safer for return values. Chrome OS and Android are moving to using zero initialization for production builds. Performance-wise, the difference between pattern and zero initialization is usually negligible, although the generated code for zero initialization is more compact. This patch renames CONFIG_INIT_STACK_ALL to CONFIG_INIT_STACK_ALL_PATTERN and introduces another config option, CONFIG_INIT_STACK_ALL_ZERO, that enables zero initialization for locals if the corresponding flags are supported by Clang. Cc: Kees Cook <keescook@chromium.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Alexander Potapenko <glider@google.com> Link: https://lore.kernel.org/r/20200616083435.223038-1-glider@google.com Reviewed-by: Maciej Żenczykowski <maze@google.com> Signed-off-by: Kees Cook <keescook@chromium.org>
2020-06-16 08:34:35 +00:00
stack: Optionally randomize kernel stack offset each syscall This provides the ability for architectures to enable kernel stack base address offset randomization. This feature is controlled by the boot param "randomize_kstack_offset=on/off", with its default value set by CONFIG_RANDOMIZE_KSTACK_OFFSET_DEFAULT. This feature is based on the original idea from the last public release of PaX's RANDKSTACK feature: https://pax.grsecurity.net/docs/randkstack.txt All the credit for the original idea goes to the PaX team. Note that the design and implementation of this upstream randomize_kstack_offset feature differs greatly from the RANDKSTACK feature (see below). Reasoning for the feature: This feature aims to make harder the various stack-based attacks that rely on deterministic stack structure. We have had many such attacks in past (just to name few): https://jon.oberheide.org/files/infiltrate12-thestackisback.pdf https://jon.oberheide.org/files/stackjacking-infiltrate11.pdf https://googleprojectzero.blogspot.com/2016/06/exploiting-recursion-in-linux-kernel_20.html As Linux kernel stack protections have been constantly improving (vmap-based stack allocation with guard pages, removal of thread_info, STACKLEAK), attackers have had to find new ways for their exploits to work. They have done so, continuing to rely on the kernel's stack determinism, in situations where VMAP_STACK and THREAD_INFO_IN_TASK_STRUCT were not relevant. For example, the following recent attacks would have been hampered if the stack offset was non-deterministic between syscalls: https://repositorio-aberto.up.pt/bitstream/10216/125357/2/374717.pdf (page 70: targeting the pt_regs copy with linear stack overflow) https://a13xp0p0v.github.io/2020/02/15/CVE-2019-18683.html (leaked stack address from one syscall as a target during next syscall) The main idea is that since the stack offset is randomized on each system call, it is harder for an attack to reliably land in any particular place on the thread stack, even with address exposures, as the stack base will change on the next syscall. Also, since randomization is performed after placing pt_regs, the ptrace-based approach[1] to discover the randomized offset during a long-running syscall should not be possible. Design description: During most of the kernel's execution, it runs on the "thread stack", which is pretty deterministic in its structure: it is fixed in size, and on every entry from userspace to kernel on a syscall the thread stack starts construction from an address fetched from the per-cpu cpu_current_top_of_stack variable. The first element to be pushed to the thread stack is the pt_regs struct that stores all required CPU registers and syscall parameters. Finally the specific syscall function is called, with the stack being used as the kernel executes the resulting request. The goal of randomize_kstack_offset feature is to add a random offset after the pt_regs has been pushed to the stack and before the rest of the thread stack is used during the syscall processing, and to change it every time a process issues a syscall. The source of randomness is currently architecture-defined (but x86 is using the low byte of rdtsc()). Future improvements for different entropy sources is possible, but out of scope for this patch. Further more, to add more unpredictability, new offsets are chosen at the end of syscalls (the timing of which should be less easy to measure from userspace than at syscall entry time), and stored in a per-CPU variable, so that the life of the value does not stay explicitly tied to a single task. As suggested by Andy Lutomirski, the offset is added using alloca() and an empty asm() statement with an output constraint, since it avoids changes to assembly syscall entry code, to the unwinder, and provides correct stack alignment as defined by the compiler. In order to make this available by default with zero performance impact for those that don't want it, it is boot-time selectable with static branches. This way, if the overhead is not wanted, it can just be left turned off with no performance impact. The generated assembly for x86_64 with GCC looks like this: ... ffffffff81003977: 65 8b 05 02 ea 00 7f mov %gs:0x7f00ea02(%rip),%eax # 12380 <kstack_offset> ffffffff8100397e: 25 ff 03 00 00 and $0x3ff,%eax ffffffff81003983: 48 83 c0 0f add $0xf,%rax ffffffff81003987: 25 f8 07 00 00 and $0x7f8,%eax ffffffff8100398c: 48 29 c4 sub %rax,%rsp ffffffff8100398f: 48 8d 44 24 0f lea 0xf(%rsp),%rax ffffffff81003994: 48 83 e0 f0 and $0xfffffffffffffff0,%rax ... As a result of the above stack alignment, this patch introduces about 5 bits of randomness after pt_regs is spilled to the thread stack on x86_64, and 6 bits on x86_32 (since its has 1 fewer bit required for stack alignment). The amount of entropy could be adjusted based on how much of the stack space we wish to trade for security. My measure of syscall performance overhead (on x86_64): lmbench: /usr/lib/lmbench/bin/x86_64-linux-gnu/lat_syscall -N 10000 null randomize_kstack_offset=y Simple syscall: 0.7082 microseconds randomize_kstack_offset=n Simple syscall: 0.7016 microseconds So, roughly 0.9% overhead growth for a no-op syscall, which is very manageable. And for people that don't want this, it's off by default. There are two gotchas with using the alloca() trick. First, compilers that have Stack Clash protection (-fstack-clash-protection) enabled by default (e.g. Ubuntu[3]) add pagesize stack probes to any dynamic stack allocations. While the randomization offset is always less than a page, the resulting assembly would still contain (unreachable!) probing routines, bloating the resulting assembly. To avoid this, -fno-stack-clash-protection is unconditionally added to the kernel Makefile since this is the only dynamic stack allocation in the kernel (now that VLAs have been removed) and it is provably safe from Stack Clash style attacks. The second gotcha with alloca() is a negative interaction with -fstack-protector*, in that it sees the alloca() as an array allocation, which triggers the unconditional addition of the stack canary function pre/post-amble which slows down syscalls regardless of the static branch. In order to avoid adding this unneeded check and its associated performance impact, architectures need to carefully remove uses of -fstack-protector-strong (or -fstack-protector) in the compilation units that use the add_random_kstack() macro and to audit the resulting stack mitigation coverage (to make sure no desired coverage disappears). No change is visible for this on x86 because the stack protector is already unconditionally disabled for the compilation unit, but the change is required on arm64. There is, unfortunately, no attribute that can be used to disable stack protector for specific functions. Comparison to PaX RANDKSTACK feature: The RANDKSTACK feature randomizes the location of the stack start (cpu_current_top_of_stack), i.e. including the location of pt_regs structure itself on the stack. Initially this patch followed the same approach, but during the recent discussions[2], it has been determined to be of a little value since, if ptrace functionality is available for an attacker, they can use PTRACE_PEEKUSR/PTRACE_POKEUSR to read/write different offsets in the pt_regs struct, observe the cache behavior of the pt_regs accesses, and figure out the random stack offset. Another difference is that the random offset is stored in a per-cpu variable, rather than having it be per-thread. As a result, these implementations differ a fair bit in their implementation details and results, though obviously the intent is similar. [1] https://lore.kernel.org/kernel-hardening/2236FBA76BA1254E88B949DDB74E612BA4BC57C1@IRSMSX102.ger.corp.intel.com/ [2] https://lore.kernel.org/kernel-hardening/20190329081358.30497-1-elena.reshetova@intel.com/ [3] https://lists.ubuntu.com/archives/ubuntu-devel/2019-June/040741.html Co-developed-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20210401232347.2791257-4-keescook@chromium.org
2021-04-01 23:23:44 +00:00
# While VLAs have been removed, GCC produces unreachable stack probes
# for the randomize_kstack_offset feature. Disable it for all compilers.
KBUILD_CFLAGS += $(call cc-option, -fno-stack-clash-protection)
hardening: Introduce CONFIG_ZERO_CALL_USED_REGS When CONFIG_ZERO_CALL_USED_REGS is enabled, build the kernel with "-fzero-call-used-regs=used-gpr" (in GCC 11). This option will zero any caller-used register contents just before returning from a function, ensuring that temporary values are not leaked beyond the function boundary. This means that register contents are less likely to be available for side channel attacks and information exposures. Additionally this helps reduce the number of useful ROP gadgets in the kernel image by about 20%: $ ROPgadget.py --nosys --nojop --binary vmlinux.stock | tail -n1 Unique gadgets found: 337245 $ ROPgadget.py --nosys --nojop --binary vmlinux.zero-call-regs | tail -n1 Unique gadgets found: 267175 and more notably removes simple "write-what-where" gadgets: $ ROPgadget.py --ropchain --binary vmlinux.stock | sed -n '/Step 1/,/Step 2/p' - Step 1 -- Write-what-where gadgets [+] Gadget found: 0xffffffff8102d76c mov qword ptr [rsi], rdx ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff8104d7c8 pop rdx ; ret [-] Can't find the 'xor rdx, rdx' gadget. Try with another 'mov [reg], reg' [+] Gadget found: 0xffffffff814c2b4c mov qword ptr [rsi], rdi ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff81001e51 pop rdi ; ret [-] Can't find the 'xor rdi, rdi' gadget. Try with another 'mov [reg], reg' [+] Gadget found: 0xffffffff81540d61 mov qword ptr [rsi], rdi ; pop rbx ; pop rbp ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff81001e51 pop rdi ; ret [-] Can't find the 'xor rdi, rdi' gadget. Try with another 'mov [reg], reg' [+] Gadget found: 0xffffffff8105341e mov qword ptr [rsi], rax ; ret [+] Gadget found: 0xffffffff81000cf5 pop rsi ; ret [+] Gadget found: 0xffffffff81029a11 pop rax ; ret [+] Gadget found: 0xffffffff811f1c3b xor rax, rax ; ret - Step 2 -- Init syscall number gadgets $ ROPgadget.py --ropchain --binary vmlinux.zero* | sed -n '/Step 1/,/Step 2/p' - Step 1 -- Write-what-where gadgets [-] Can't find the 'mov qword ptr [r64], r64' gadget For an x86_64 parallel build tests, this has a less than 1% performance impact, and grows the image size less than 1%: $ size vmlinux.stock vmlinux.zero-call-regs text data bss dec hex filename 22437676 8559152 14127340 45124168 2b08a48 vmlinux.stock 22453184 8563248 14110956 45127388 2b096dc vmlinux.zero-call-regs Impact for other architectures may vary. For example, arm64 sees a 5.5% image size growth, mainly due to needing to always clear x16 and x17: https://lore.kernel.org/lkml/20210510134503.GA88495@C02TD0UTHF1T.local/ Signed-off-by: Kees Cook <keescook@chromium.org>
2021-04-13 02:56:54 +00:00
# Clear used registers at func exit (to reduce data lifetime and ROP gadgets).
ifdef CONFIG_ZERO_CALL_USED_REGS
KBUILD_CFLAGS += -fzero-call-used-regs=used-gpr
endif
ifdef CONFIG_FUNCTION_TRACER
ifdef CONFIG_FTRACE_MCOUNT_USE_CC
CC_FLAGS_FTRACE += -mrecord-mcount
ifdef CONFIG_HAVE_NOP_MCOUNT
ifeq ($(call cc-option-yn, -mnop-mcount),y)
CC_FLAGS_FTRACE += -mnop-mcount
CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
endif
endif
endif
ifdef CONFIG_FTRACE_MCOUNT_USE_OBJTOOL
ifdef CONFIG_HAVE_OBJTOOL_NOP_MCOUNT
CC_FLAGS_USING += -DCC_USING_NOP_MCOUNT
endif
endif
ifdef CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT
ifdef CONFIG_HAVE_C_RECORDMCOUNT
BUILD_C_RECORDMCOUNT := y
export BUILD_C_RECORDMCOUNT
endif
endif
ifdef CONFIG_HAVE_FENTRY
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
# s390-linux-gnu-gcc did not support -mfentry until gcc-9.
ifeq ($(call cc-option-yn, -mfentry),y)
CC_FLAGS_FTRACE += -mfentry
CC_FLAGS_USING += -DCC_USING_FENTRY
endif
endif
export CC_FLAGS_FTRACE
KBUILD_CFLAGS += $(CC_FLAGS_FTRACE) $(CC_FLAGS_USING)
KBUILD_AFLAGS += $(CC_FLAGS_USING)
endif
# We trigger additional mismatches with less inlining
ifdef CONFIG_DEBUG_SECTION_MISMATCH
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
KBUILD_CFLAGS += -fno-inline-functions-called-once
endif
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# `rustc`'s `-Zfunction-sections` applies to data too (as of 1.59.0).
ifdef CONFIG_LD_DEAD_CODE_DATA_ELIMINATION
KBUILD_CFLAGS_KERNEL += -ffunction-sections -fdata-sections
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS_KERNEL += -Zfunction-sections=y
LDFLAGS_vmlinux += --gc-sections
endif
ifdef CONFIG_SHADOW_CALL_STACK
ifndef CONFIG_DYNAMIC_SCS
CC_FLAGS_SCS := -fsanitize=shadow-call-stack
KBUILD_CFLAGS += $(CC_FLAGS_SCS)
endif
export CC_FLAGS_SCS
endif
kbuild: add support for Clang LTO This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
2020-12-11 18:46:19 +00:00
ifdef CONFIG_LTO_CLANG
ifdef CONFIG_LTO_CLANG_THIN
CC_FLAGS_LTO := -flto=thin -fsplit-lto-unit
kbuild: add support for Clang LTO This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
2020-12-11 18:46:19 +00:00
else
CC_FLAGS_LTO := -flto
kbuild: add support for Clang LTO This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
2020-12-11 18:46:19 +00:00
endif
CC_FLAGS_LTO += -fvisibility=hidden
# Limit inlining across translation units to reduce binary size
KBUILD_LDFLAGS += -mllvm -import-instr-limit=5
endif
kbuild: add support for Clang LTO This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
2020-12-11 18:46:19 +00:00
ifdef CONFIG_LTO
KBUILD_CFLAGS += -fno-lto $(CC_FLAGS_LTO)
KBUILD_AFLAGS += -fno-lto
kbuild: add support for Clang LTO This change adds build system support for Clang's Link Time Optimization (LTO). With -flto, instead of ELF object files, Clang produces LLVM bitcode, which is compiled into native code at link time, allowing the final binary to be optimized globally. For more details, see: https://llvm.org/docs/LinkTimeOptimization.html The Kconfig option CONFIG_LTO_CLANG is implemented as a choice, which defaults to LTO being disabled. To use LTO, the architecture must select ARCH_SUPPORTS_LTO_CLANG and support: - compiling with Clang, - compiling all assembly code with Clang's integrated assembler, - and linking with LLD. While using CONFIG_LTO_CLANG_FULL results in the best runtime performance, the compilation is not scalable in time or memory. CONFIG_LTO_CLANG_THIN enables ThinLTO, which allows parallel optimization and faster incremental builds. ThinLTO is used by default if the architecture also selects ARCH_SUPPORTS_LTO_CLANG_THIN: https://clang.llvm.org/docs/ThinLTO.html To enable LTO, LLVM tools must be used to handle bitcode files, by passing LLVM=1 and LLVM_IAS=1 options to make: $ make LLVM=1 LLVM_IAS=1 defconfig $ scripts/config -e LTO_CLANG_THIN $ make LLVM=1 LLVM_IAS=1 To prepare for LTO support with other compilers, common parts are gated behind the CONFIG_LTO option, and LTO can be disabled for specific files by filtering out CC_FLAGS_LTO. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20201211184633.3213045-3-samitolvanen@google.com
2020-12-11 18:46:19 +00:00
export CC_FLAGS_LTO
endif
add support for Clang CFI This change adds support for Clang’s forward-edge Control Flow Integrity (CFI) checking. With CONFIG_CFI_CLANG, the compiler injects a runtime check before each indirect function call to ensure the target is a valid function with the correct static type. This restricts possible call targets and makes it more difficult for an attacker to exploit bugs that allow the modification of stored function pointers. For more details, see: https://clang.llvm.org/docs/ControlFlowIntegrity.html Clang requires CONFIG_LTO_CLANG to be enabled with CFI to gain visibility to possible call targets. Kernel modules are supported with Clang’s cross-DSO CFI mode, which allows checking between independently compiled components. With CFI enabled, the compiler injects a __cfi_check() function into the kernel and each module for validating local call targets. For cross-module calls that cannot be validated locally, the compiler calls the global __cfi_slowpath_diag() function, which determines the target module and calls the correct __cfi_check() function. This patch includes a slowpath implementation that uses __module_address() to resolve call targets, and with CONFIG_CFI_CLANG_SHADOW enabled, a shadow map that speeds up module look-ups by ~3x. Clang implements indirect call checking using jump tables and offers two methods of generating them. With canonical jump tables, the compiler renames each address-taken function to <function>.cfi and points the original symbol to a jump table entry, which passes __cfi_check() validation. This isn’t compatible with stand-alone assembly code, which the compiler doesn’t instrument, and would result in indirect calls to assembly code to fail. Therefore, we default to using non-canonical jump tables instead, where the compiler generates a local jump table entry <function>.cfi_jt for each address-taken function, and replaces all references to the function with the address of the jump table entry. Note that because non-canonical jump table addresses are local to each component, they break cross-module function address equality. Specifically, the address of a global function will be different in each module, as it's replaced with the address of a local jump table entry. If this address is passed to a different module, it won’t match the address of the same function taken there. This may break code that relies on comparing addresses passed from other components. CFI checking can be disabled in a function with the __nocfi attribute. Additionally, CFI can be disabled for an entire compilation unit by filtering out CC_FLAGS_CFI. By default, CFI failures result in a kernel panic to stop a potential exploit. CONFIG_CFI_PERMISSIVE enables a permissive mode, where the kernel prints out a rate-limited warning instead, and allows execution to continue. This option is helpful for locating type mismatches, but should only be enabled during development. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210408182843.1754385-2-samitolvanen@google.com
2021-04-08 18:28:26 +00:00
ifdef CONFIG_CFI_CLANG
CC_FLAGS_CFI := -fsanitize=kcfi
add support for Clang CFI This change adds support for Clang’s forward-edge Control Flow Integrity (CFI) checking. With CONFIG_CFI_CLANG, the compiler injects a runtime check before each indirect function call to ensure the target is a valid function with the correct static type. This restricts possible call targets and makes it more difficult for an attacker to exploit bugs that allow the modification of stored function pointers. For more details, see: https://clang.llvm.org/docs/ControlFlowIntegrity.html Clang requires CONFIG_LTO_CLANG to be enabled with CFI to gain visibility to possible call targets. Kernel modules are supported with Clang’s cross-DSO CFI mode, which allows checking between independently compiled components. With CFI enabled, the compiler injects a __cfi_check() function into the kernel and each module for validating local call targets. For cross-module calls that cannot be validated locally, the compiler calls the global __cfi_slowpath_diag() function, which determines the target module and calls the correct __cfi_check() function. This patch includes a slowpath implementation that uses __module_address() to resolve call targets, and with CONFIG_CFI_CLANG_SHADOW enabled, a shadow map that speeds up module look-ups by ~3x. Clang implements indirect call checking using jump tables and offers two methods of generating them. With canonical jump tables, the compiler renames each address-taken function to <function>.cfi and points the original symbol to a jump table entry, which passes __cfi_check() validation. This isn’t compatible with stand-alone assembly code, which the compiler doesn’t instrument, and would result in indirect calls to assembly code to fail. Therefore, we default to using non-canonical jump tables instead, where the compiler generates a local jump table entry <function>.cfi_jt for each address-taken function, and replaces all references to the function with the address of the jump table entry. Note that because non-canonical jump table addresses are local to each component, they break cross-module function address equality. Specifically, the address of a global function will be different in each module, as it's replaced with the address of a local jump table entry. If this address is passed to a different module, it won’t match the address of the same function taken there. This may break code that relies on comparing addresses passed from other components. CFI checking can be disabled in a function with the __nocfi attribute. Additionally, CFI can be disabled for an entire compilation unit by filtering out CC_FLAGS_CFI. By default, CFI failures result in a kernel panic to stop a potential exploit. CONFIG_CFI_PERMISSIVE enables a permissive mode, where the kernel prints out a rate-limited warning instead, and allows execution to continue. This option is helpful for locating type mismatches, but should only be enabled during development. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org> Tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Kees Cook <keescook@chromium.org> Link: https://lore.kernel.org/r/20210408182843.1754385-2-samitolvanen@google.com
2021-04-08 18:28:26 +00:00
KBUILD_CFLAGS += $(CC_FLAGS_CFI)
export CC_FLAGS_CFI
endif
arch: add ARCH_HAS_KERNEL_FPU_SUPPORT Several architectures provide an API to enable the FPU and run floating-point SIMD code in kernel space. However, the function names, header locations, and semantics are inconsistent across architectures, and FPU support may be gated behind other Kconfig options. provide a standard way for architectures to declare that kernel space FPU support is available. Architectures selecting this option must implement what is currently the most common API (kernel_fpu_begin() and kernel_fpu_end(), plus a new function kernel_fpu_available()) and provide the appropriate CFLAGS for compiling floating-point C code. Link: https://lkml.kernel.org/r/20240329072441.591471-2-samuel.holland@sifive.com Signed-off-by: Samuel Holland <samuel.holland@sifive.com> Suggested-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Christian König <christian.koenig@amd.com> Cc: Alex Deucher <alexander.deucher@amd.com> Cc: Borislav Petkov (AMD) <bp@alien8.de> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Huacai Chen <chenhuacai@kernel.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Palmer Dabbelt <palmer@rivosinc.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: WANG Xuerui <git@xen0n.name> Cc: Will Deacon <will@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2024-03-29 07:18:16 +00:00
# Architectures can define flags to add/remove for floating-point support
CC_FLAGS_FPU += -D_LINUX_FPU_COMPILATION_UNIT
export CC_FLAGS_FPU
export CC_FLAGS_NO_FPU
ifneq ($(CONFIG_FUNCTION_ALIGNMENT),0)
# Set the minimal function alignment. Use the newer GCC option
# -fmin-function-alignment if it is available, or fall back to -falign-funtions.
# See also CONFIG_CC_HAS_SANE_FUNCTION_ALIGNMENT.
ifdef CONFIG_CC_HAS_MIN_FUNCTION_ALIGNMENT
KBUILD_CFLAGS += -fmin-function-alignment=$(CONFIG_FUNCTION_ALIGNMENT)
else
KBUILD_CFLAGS += -falign-functions=$(CONFIG_FUNCTION_ALIGNMENT)
./Makefile: add debug option to enable function aligned on 32 bytes Recently 0day reported many strange performance changes (regression or improvement), in which there was no obvious relation between the culprit commit and the benchmark at the first look, and it causes people to doubt the test itself is wrong. Upon further check, many of these cases are caused by the change to the alignment of kernel text or data, as whole text/data of kernel are linked together, change in one domain may affect alignments of other domains. gcc has an option '-falign-functions=n' to force text aligned, and with that option enabled, some of those performance changes will be gone, like [1][2][3]. Add this option so that developers and 0day can easily find performance bump caused by text alignment change, as tracking these strange bump is quite time consuming. Though it can't help in other cases like data alignment changes like [4]. Following is some size data for v5.7 kernel built with a RHEL config used in 0day: text data bss dec filename 19738771 13292906 5554236 38585913 vmlinux.noalign 19758591 13297002 5529660 38585253 vmlinux.align32 Raw vmlinux size in bytes: v5.7 v5.7+align32 253950832 254018000 +0.02% Some benchmark data, most of them have no big change: * hackbench: [ -1.8%, +0.5%] * fsmark: [ -3.2%, +3.4%] # ext4/xfs/btrfs * kbuild: [ -2.0%, +0.9%] * will-it-scale: [ -0.5%, +1.8%] # mmap1/pagefault3 * netperf: - TCP_CRR [+16.6%, +97.4%] - TCP_RR [-18.5%, -1.8%] - TCP_STREAM [ -1.1%, +1.9%] [1] https://lore.kernel.org/lkml/20200114085637.GA29297@shao2-debian/ [2] https://lore.kernel.org/lkml/20200330011254.GA14393@feng-iot/ [3] https://lore.kernel.org/lkml/1d98d1f0-fe84-6df7-f5bd-f4cb2cdb7f45@intel.com/ [4] https://lore.kernel.org/lkml/20200205123216.GO12867@shao2-debian/ Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Andy Shevchenko <andriy.shevchenko@intel.com> Link: http://lkml.kernel.org/r/1595475001-90945-1-git-send-email-feng.tang@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 01:34:13 +00:00
endif
endif
./Makefile: add debug option to enable function aligned on 32 bytes Recently 0day reported many strange performance changes (regression or improvement), in which there was no obvious relation between the culprit commit and the benchmark at the first look, and it causes people to doubt the test itself is wrong. Upon further check, many of these cases are caused by the change to the alignment of kernel text or data, as whole text/data of kernel are linked together, change in one domain may affect alignments of other domains. gcc has an option '-falign-functions=n' to force text aligned, and with that option enabled, some of those performance changes will be gone, like [1][2][3]. Add this option so that developers and 0day can easily find performance bump caused by text alignment change, as tracking these strange bump is quite time consuming. Though it can't help in other cases like data alignment changes like [4]. Following is some size data for v5.7 kernel built with a RHEL config used in 0day: text data bss dec filename 19738771 13292906 5554236 38585913 vmlinux.noalign 19758591 13297002 5529660 38585253 vmlinux.align32 Raw vmlinux size in bytes: v5.7 v5.7+align32 253950832 254018000 +0.02% Some benchmark data, most of them have no big change: * hackbench: [ -1.8%, +0.5%] * fsmark: [ -3.2%, +3.4%] # ext4/xfs/btrfs * kbuild: [ -2.0%, +0.9%] * will-it-scale: [ -0.5%, +1.8%] # mmap1/pagefault3 * netperf: - TCP_CRR [+16.6%, +97.4%] - TCP_RR [-18.5%, -1.8%] - TCP_STREAM [ -1.1%, +1.9%] [1] https://lore.kernel.org/lkml/20200114085637.GA29297@shao2-debian/ [2] https://lore.kernel.org/lkml/20200330011254.GA14393@feng-iot/ [3] https://lore.kernel.org/lkml/1d98d1f0-fe84-6df7-f5bd-f4cb2cdb7f45@intel.com/ [4] https://lore.kernel.org/lkml/20200205123216.GO12867@shao2-debian/ Signed-off-by: Feng Tang <feng.tang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Andi Kleen <andi.kleen@intel.com> Cc: Huang Ying <ying.huang@intel.com> Cc: Andy Shevchenko <andriy.shevchenko@intel.com> Link: http://lkml.kernel.org/r/1595475001-90945-1-git-send-email-feng.tang@intel.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2020-08-12 01:34:13 +00:00
# arch Makefile may override CC so keep this after arch Makefile is included
isystem: delete global -isystem compile option Further isolate kernel from userspace, prevent accidental inclusion of undesireable headers, mainly float.h and stdatomic.h. nds32 keeps -isystem globally due to intrinsics used in entrenched header. -isystem is selectively reenabled for some files, again, for intrinsics. Compile tested on: hexagon-defconfig hexagon-allmodconfig alpha-allmodconfig alpha-allnoconfig alpha-defconfig arm64-allmodconfig arm64-allnoconfig arm64-defconfig arm-am200epdkit arm-aspeed_g4 arm-aspeed_g5 arm-assabet arm-at91_dt arm-axm55xx arm-badge4 arm-bcm2835 arm-cerfcube arm-clps711x arm-cm_x300 arm-cns3420vb arm-colibri_pxa270 arm-colibri_pxa300 arm-collie arm-corgi arm-davinci_all arm-dove arm-ep93xx arm-eseries_pxa arm-exynos arm-ezx arm-footbridge arm-gemini arm-h3600 arm-h5000 arm-hackkit arm-hisi arm-imote2 arm-imx_v4_v5 arm-imx_v6_v7 arm-integrator arm-iop32x arm-ixp4xx arm-jornada720 arm-keystone arm-lart arm-lpc18xx arm-lpc32xx arm-lpd270 arm-lubbock arm-magician arm-mainstone arm-milbeaut_m10v arm-mini2440 arm-mmp2 arm-moxart arm-mps2 arm-multi_v4t arm-multi_v5 arm-multi_v7 arm-mv78xx0 arm-mvebu_v5 arm-mvebu_v7 arm-mxs arm-neponset arm-netwinder arm-nhk8815 arm-omap1 arm-omap2plus arm-orion5x arm-oxnas_v6 arm-palmz72 arm-pcm027 arm-pleb arm-pxa arm-pxa168 arm-pxa255-idp arm-pxa3xx arm-pxa910 arm-qcom arm-realview arm-rpc arm-s3c2410 arm-s3c6400 arm-s5pv210 arm-sama5 arm-shannon arm-shmobile arm-simpad arm-socfpga arm-spear13xx arm-spear3xx arm-spear6xx arm-spitz arm-stm32 arm-sunxi arm-tct_hammer arm-tegra arm-trizeps4 arm-u8500 arm-versatile arm-vexpress arm-vf610m4 arm-viper arm-vt8500_v6_v7 arm-xcep arm-zeus csky-allmodconfig csky-allnoconfig csky-defconfig h8300-edosk2674 h8300-h8300h-sim h8300-h8s-sim i386-allmodconfig i386-allnoconfig i386-defconfig ia64-allmodconfig ia64-allnoconfig ia64-bigsur ia64-generic ia64-gensparse ia64-tiger ia64-zx1 m68k-amcore m68k-amiga m68k-apollo m68k-atari m68k-bvme6000 m68k-hp300 m68k-m5208evb m68k-m5249evb m68k-m5272c3 m68k-m5275evb m68k-m5307c3 m68k-m5407c3 m68k-m5475evb m68k-mac m68k-multi m68k-mvme147 m68k-mvme16x m68k-q40 m68k-stmark2 m68k-sun3 m68k-sun3x microblaze-allmodconfig microblaze-allnoconfig microblaze-mmu mips-ar7 mips-ath25 mips-ath79 mips-bcm47xx mips-bcm63xx mips-bigsur mips-bmips_be mips-bmips_stb mips-capcella mips-cavium_octeon mips-ci20 mips-cobalt mips-cu1000-neo mips-cu1830-neo mips-db1xxx mips-decstation mips-decstation_64 mips-decstation_r4k mips-e55 mips-fuloong2e mips-gcw0 mips-generic mips-gpr mips-ip22 mips-ip27 mips-ip28 mips-ip32 mips-jazz mips-jmr3927 mips-lemote2f mips-loongson1b mips-loongson1c mips-loongson2k mips-loongson3 mips-malta mips-maltaaprp mips-malta_kvm mips-malta_qemu_32r6 mips-maltasmvp mips-maltasmvp_eva mips-maltaup mips-maltaup_xpa mips-mpc30x mips-mtx1 mips-nlm_xlp mips-nlm_xlr mips-omega2p mips-pic32mzda mips-pistachio mips-qi_lb60 mips-rb532 mips-rbtx49xx mips-rm200 mips-rs90 mips-rt305x mips-sb1250_swarm mips-tb0219 mips-tb0226 mips-tb0287 mips-vocore2 mips-workpad mips-xway nds32-allmodconfig nds32-allnoconfig nds32-defconfig nios2-10m50 nios2-3c120 nios2-allmodconfig nios2-allnoconfig openrisc-allmodconfig openrisc-allnoconfig openrisc-or1klitex openrisc-or1ksim openrisc-simple_smp parisc-allnoconfig parisc-generic-32bit parisc-generic-64bit powerpc-acadia powerpc-adder875 powerpc-akebono powerpc-amigaone powerpc-arches powerpc-asp8347 powerpc-bamboo powerpc-bluestone powerpc-canyonlands powerpc-cell powerpc-chrp32 powerpc-cm5200 powerpc-currituck powerpc-ebony powerpc-eiger powerpc-ep8248e powerpc-ep88xc powerpc-fsp2 powerpc-g5 powerpc-gamecube powerpc-ge_imp3a powerpc-holly powerpc-icon powerpc-iss476-smp powerpc-katmai powerpc-kilauea powerpc-klondike powerpc-kmeter1 powerpc-ksi8560 powerpc-linkstation powerpc-lite5200b powerpc-makalu powerpc-maple powerpc-mgcoge powerpc-microwatt powerpc-motionpro powerpc-mpc512x powerpc-mpc5200 powerpc-mpc7448_hpc2 powerpc-mpc8272_ads powerpc-mpc8313_rdb powerpc-mpc8315_rdb powerpc-mpc832x_mds powerpc-mpc832x_rdb powerpc-mpc834x_itx powerpc-mpc834x_itxgp powerpc-mpc834x_mds powerpc-mpc836x_mds powerpc-mpc836x_rdk powerpc-mpc837x_mds powerpc-mpc837x_rdb powerpc-mpc83xx powerpc-mpc8540_ads powerpc-mpc8560_ads powerpc-mpc85xx_cds powerpc-mpc866_ads powerpc-mpc885_ads powerpc-mvme5100 powerpc-obs600 powerpc-pasemi powerpc-pcm030 powerpc-pmac32 powerpc-powernv powerpc-ppa8548 powerpc-ppc40x powerpc-ppc44x powerpc-ppc64 powerpc-ppc64e powerpc-ppc6xx powerpc-pq2fads powerpc-ps3 powerpc-pseries powerpc-rainier powerpc-redwood powerpc-sam440ep powerpc-sbc8548 powerpc-sequoia powerpc-skiroot powerpc-socrates powerpc-storcenter powerpc-stx_gp3 powerpc-taishan powerpc-tqm5200 powerpc-tqm8540 powerpc-tqm8541 powerpc-tqm8548 powerpc-tqm8555 powerpc-tqm8560 powerpc-tqm8xx powerpc-walnut powerpc-warp powerpc-wii powerpc-xes_mpc85xx riscv-allmodconfig riscv-allnoconfig riscv-nommu_k210 riscv-nommu_k210_sdcard riscv-nommu_virt riscv-rv32 s390-allmodconfig s390-allnoconfig s390-debug s390-zfcpdump sh-ap325rxa sh-apsh4a3a sh-apsh4ad0a sh-dreamcast sh-ecovec24 sh-ecovec24-romimage sh-edosk7705 sh-edosk7760 sh-espt sh-hp6xx sh-j2 sh-kfr2r09 sh-kfr2r09-romimage sh-landisk sh-lboxre2 sh-magicpanelr2 sh-microdev sh-migor sh-polaris sh-r7780mp sh-r7785rp sh-rsk7201 sh-rsk7203 sh-rsk7264 sh-rsk7269 sh-rts7751r2d1 sh-rts7751r2dplus sh-sdk7780 sh-sdk7786 sh-se7206 sh-se7343 sh-se7619 sh-se7705 sh-se7712 sh-se7721 sh-se7722 sh-se7724 sh-se7750 sh-se7751 sh-se7780 sh-secureedge5410 sh-sh03 sh-sh2007 sh-sh7710voipgw sh-sh7724_generic sh-sh7757lcr sh-sh7763rdp sh-sh7770_generic sh-sh7785lcr sh-sh7785lcr_32bit sh-shmin sh-shx3 sh-titan sh-ul2 sh-urquell sparc-allmodconfig sparc-allnoconfig sparc-sparc32 sparc-sparc64 um-i386-allmodconfig um-i386-allnoconfig um-i386-defconfig um-x86_64-allmodconfig um-x86_64-allnoconfig x86_64-allmodconfig x86_64-allnoconfig x86_64-defconfig xtensa-allmodconfig xtensa-allnoconfig xtensa-audio_kc705 xtensa-cadence_csp xtensa-common xtensa-generic_kc705 xtensa-iss xtensa-nommu_kc705 xtensa-smp_lx200 xtensa-virt xtensa-xip_kc705 Tested-by: Nathan Chancellor <nathan@kernel.org> # build (hexagon) Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Acked-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-02 20:43:15 +00:00
NOSTDINC_FLAGS += -nostdinc
# To gain proper coverage for CONFIG_UBSAN_BOUNDS and CONFIG_FORTIFY_SOURCE,
# the kernel uses only C99 flexible arrays for dynamically sized trailing
# arrays. Enforce this for everything that may examine structure sizes and
# perform bounds checking.
KBUILD_CFLAGS += $(call cc-option, -fstrict-flex-arrays=3)
#Currently, disable -Wstringop-overflow for GCC 11, globally.
KBUILD_CFLAGS-$(CONFIG_CC_NO_STRINGOP_OVERFLOW) += $(call cc-option, -Wno-stringop-overflow)
KBUILD_CFLAGS-$(CONFIG_CC_STRINGOP_OVERFLOW) += $(call cc-option, -Wstringop-overflow)
# disable invalid "can't wrap" optimizations for signed / pointers
KBUILD_CFLAGS += -fno-strict-overflow
# Make sure -fstack-check isn't enabled (like gentoo apparently did)
KBUILD_CFLAGS += -fno-stack-check
# conserve stack if available
Makefile: remove stale cc-option checks cc-option, cc-option-yn, and cc-disable-warning all invoke the compiler during build time, and can slow down the build when these checks become stale for our supported compilers, whose minimally supported versions increases over time. See Documentation/process/changes.rst for the current supported minimal versions (GCC 4.9+, clang 10.0.1+). Compiler version support for these flags may be verified on godbolt.org. The following flags are GCC only and supported since at least GCC 4.9. Remove cc-option and cc-disable-warning tests. * -fno-tree-loop-im * -Wno-maybe-uninitialized * -fno-reorder-blocks * -fno-ipa-cp-clone * -fno-partial-inlining * -femit-struct-debug-baseonly * -fno-inline-functions-called-once * -fconserve-stack The following flags are supported by all supported versions of GCC and Clang. Remove their cc-option, cc-option-yn, and cc-disable-warning tests. * -fno-delete-null-pointer-checks * -fno-var-tracking * -Wno-array-bounds The following configs are made dependent on GCC, since they use GCC specific flags. * READABLE_ASM * DEBUG_SECTION_MISMATCH -mfentry was not supported by s390-linux-gnu-gcc until gcc-9+, add a comment. --param=allow-store-data-races=0 was renamed to -fno-allow-store-data-races in the GCC 10 release; add a comment. -Wmaybe-uninitialized (GCC specific) was being added for CONFIG_GCOV, then again unconditionally; add it only once. Also, base RETPOLINE_CFLAGS and RETPOLINE_VDSO_CFLAGS on CONFIC_CC_IS_* then remove cc-option tests for Clang. Link: https://github.com/ClangBuiltLinux/linux/issues/1436 Acked-by: Miguel Ojeda <ojeda@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-16 20:25:01 +00:00
ifdef CONFIG_CC_IS_GCC
KBUILD_CFLAGS += -fconserve-stack
endif
# change __FILE__ to the relative path from the srctree
KBUILD_CPPFLAGS += $(call cc-option,-fmacro-prefix-map=$(srctree)/=)
# include additional Makefiles when needed
include-y := scripts/Makefile.extrawarn
include-$(CONFIG_DEBUG_INFO) += scripts/Makefile.debug
kbuild: avoid too many execution of scripts/pahole-flags.sh scripts/pahole-flags.sh is executed so many times. You can confirm it, as follows: $ cat <<EOF >> scripts/pahole-flags.sh > echo "scripts/pahole-flags.sh was executed" >&2 > EOF $ make -s scripts/pahole-flags.sh was executed scripts/pahole-flags.sh was executed scripts/pahole-flags.sh was executed scripts/pahole-flags.sh was executed scripts/pahole-flags.sh was executed [ lots of repeated lines... ] This scripts is executed more than 20 times during the kernel build because PAHOLE_FLAGS is a recursively expanded variable and exported to sub-processes. With GNU Make >= 4.4, it is executed more than 60 times because exported variables are also passed to other $(shell ) invocations. Without careful coding, it is known to cause an exponential fork explosion. [1] The use of $(shell ) in an exported recursive variable is likely wrong because $(shell ) is always evaluated due to the 'export' keyword, and the evaluation can occur multiple times by the nature of recursive variables. Convert the shell script to a Makefile, which is included only when CONFIG_DEBUG_INFO_BTF=y. [1]: https://savannah.gnu.org/bugs/index.php?64746 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Alan Maguire <alan.maguire@oracle.com> Tested-by: Alan Maguire <alan.maguire@oracle.com> Reviewed-by: Nicolas Schier <n.schier@avm.de> Tested-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Miguel Ojeda <ojeda@kernel.org> Acked-by: Jiri Olsa <jolsa@kernel.org> Reviewed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com>
2023-10-18 15:19:48 +00:00
include-$(CONFIG_DEBUG_INFO_BTF)+= scripts/Makefile.btf
include-$(CONFIG_KASAN) += scripts/Makefile.kasan
include-$(CONFIG_KCSAN) += scripts/Makefile.kcsan
kmsan: add KMSAN runtime core For each memory location KernelMemorySanitizer maintains two types of metadata: 1. The so-called shadow of that location - а byte:byte mapping describing whether or not individual bits of memory are initialized (shadow is 0) or not (shadow is 1). 2. The origins of that location - а 4-byte:4-byte mapping containing 4-byte IDs of the stack traces where uninitialized values were created. Each struct page now contains pointers to two struct pages holding KMSAN metadata (shadow and origins) for the original struct page. Utility routines in mm/kmsan/core.c and mm/kmsan/shadow.c handle the metadata creation, addressing, copying and checking. mm/kmsan/report.c performs error reporting in the cases an uninitialized value is used in a way that leads to undefined behavior. KMSAN compiler instrumentation is responsible for tracking the metadata along with the kernel memory. mm/kmsan/instrumentation.c provides the implementation for instrumentation hooks that are called from files compiled with -fsanitize=kernel-memory. To aid parameter passing (also done at instrumentation level), each task_struct now contains a struct kmsan_task_state used to track the metadata of function parameters and return values for that task. Finally, this patch provides CONFIG_KMSAN that enables KMSAN, and declares CFLAGS_KMSAN, which are applied to files compiled with KMSAN. The KMSAN_SANITIZE:=n Makefile directive can be used to completely disable KMSAN instrumentation for certain files. Similarly, KMSAN_ENABLE_CHECKS:=n disables KMSAN checks and makes newly created stack memory initialized. Users can also use functions from include/linux/kmsan-checks.h to mark certain memory regions as uninitialized or initialized (this is called "poisoning" and "unpoisoning") or check that a particular region is initialized. Link: https://lkml.kernel.org/r/20220915150417.722975-12-glider@google.com Signed-off-by: Alexander Potapenko <glider@google.com> Acked-by: Marco Elver <elver@google.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrey Konovalov <andreyknvl@gmail.com> Cc: Andrey Konovalov <andreyknvl@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Christoph Hellwig <hch@lst.de> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Eric Biggers <ebiggers@kernel.org> Cc: Eric Dumazet <edumazet@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Ilya Leoshkevich <iii@linux.ibm.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Kees Cook <keescook@chromium.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Matthew Wilcox <willy@infradead.org> Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Pekka Enberg <penberg@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vasily Gorbik <gor@linux.ibm.com> Cc: Vegard Nossum <vegard.nossum@oracle.com> Cc: Vlastimil Babka <vbabka@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2022-09-15 15:03:45 +00:00
include-$(CONFIG_KMSAN) += scripts/Makefile.kmsan
include-$(CONFIG_UBSAN) += scripts/Makefile.ubsan
include-$(CONFIG_KCOV) += scripts/Makefile.kcov
include-$(CONFIG_RANDSTRUCT) += scripts/Makefile.randstruct
include-$(CONFIG_GCC_PLUGINS) += scripts/Makefile.gcc-plugins
include $(addprefix $(srctree)/, $(include-y))
# scripts/Makefile.gcc-plugins is intentionally included last.
# Do not add $(call cc-option,...) below this line. When you build the kernel
# from the clean source tree, the GCC plugins do not exist at this point.
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# Add user supplied CPPFLAGS, AFLAGS, CFLAGS and RUSTFLAGS as the last assignments
KBUILD_CPPFLAGS += $(KCPPFLAGS)
KBUILD_AFLAGS += $(KAFLAGS)
KBUILD_CFLAGS += $(KCFLAGS)
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
KBUILD_RUSTFLAGS += $(KRUSTFLAGS)
KBUILD_LDFLAGS_MODULE += --build-id=sha1
LDFLAGS_vmlinux += --build-id=sha1
Makefile: link with -z noexecstack --no-warn-rwx-segments Users of GNU ld (BFD) from binutils 2.39+ will observe multiple instances of a new warning when linking kernels in the form: ld: warning: vmlinux: missing .note.GNU-stack section implies executable stack ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker ld: warning: vmlinux has a LOAD segment with RWX permissions Generally, we would like to avoid the stack being executable. Because there could be a need for the stack to be executable, assembler sources have to opt-in to this security feature via explicit creation of the .note.GNU-stack feature (which compilers create by default) or command line flag --noexecstack. Or we can simply tell the linker the production of such sections is irrelevant and to link the stack as --noexecstack. LLVM's LLD linker defaults to -z noexecstack, so this flag isn't strictly necessary when linking with LLD, only BFD, but it doesn't hurt to be explicit here for all linkers IMO. --no-warn-rwx-segments is currently BFD specific and only available in the current latest release, so it's wrapped in an ld-option check. While the kernel makes extensive usage of ELF sections, it doesn't use permissions from ELF segments. Link: https://lore.kernel.org/linux-block/3af4127a-f453-4cf7-f133-a181cce06f73@kernel.dk/ Link: https://sourceware.org/git/?p=binutils-gdb.git;a=commit;h=ba951afb99912da01a6e8434126b8fac7aa75107 Link: https://github.com/llvm/llvm-project/issues/57009 Reported-and-tested-by: Jens Axboe <axboe@kernel.dk> Suggested-by: Fangrui Song <maskray@google.com> Signed-off-by: Nick Desaulniers <ndesaulniers@google.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2022-08-10 22:24:40 +00:00
KBUILD_LDFLAGS += -z noexecstack
ifeq ($(CONFIG_LD_IS_BFD),y)
KBUILD_LDFLAGS += $(call ld-option,--no-warn-rwx-segments)
endif
ifeq ($(CONFIG_STRIP_ASM_SYMS),y)
LDFLAGS_vmlinux += -X
endif
ifeq ($(CONFIG_RELR),y)
2023-04-11 20:09:44 +00:00
# ld.lld before 15 did not support -z pack-relative-relocs.
LDFLAGS_vmlinux += $(call ld-option,--pack-dyn-relocs=relr,-z pack-relative-relocs)
endif
# We never want expected sections to be placed heuristically by the
# linker. All sections should be explicitly named in the linker script.
ifdef CONFIG_LD_ORPHAN_WARN
LDFLAGS_vmlinux += --orphan-handling=$(CONFIG_LD_ORPHAN_WARN_LEVEL)
endif
kbuild: add infrastructure to build userspace programs Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154), but it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] are often used for building the kernel, but they do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use the 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-04-29 03:45:14 +00:00
# Align the bit size of userspace programs with the kernel
KBUILD_USERCFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
KBUILD_USERLDFLAGS += $(filter -m32 -m64 --target=%, $(KBUILD_CFLAGS))
kbuild: add infrastructure to build userspace programs Kbuild supports the infrastructure to build host programs, but there was no support to build userspace programs for the target architecture (i.e. the same architecture as the kernel). Sam Ravnborg worked on this in 2014 (https://lkml.org/lkml/2014/7/13/154), but it was not merged. One problem at that time was, there was no good way to know whether $(CC) can link standalone programs. In fact, pre-built kernel.org toolchains [1] are often used for building the kernel, but they do not provide libc. Now, we can handle this cleanly because the compiler capability is evaluated at the Kconfig time. If $(CC) cannot link standalone programs, the relevant options are hidden by 'depends on CC_CAN_LINK'. The implementation just mimics scripts/Makefile.host The userspace programs are compiled with the same flags as the host programs. In addition, it uses -m32 or -m64 if it is found in $(KBUILD_CFLAGS). This new syntax has two usecases. - Sample programs Several userspace programs under samples/ include UAPI headers installed in usr/include. Most of them were previously built for the host architecture just to use the 'hostprogs' syntax. However, 'make headers' always works for the target architecture. This caused the arch mismatch in cross-compiling. To fix this distortion, sample code should be built for the target architecture. - Bpfilter net/bpfilter/Makefile compiles bpfilter_umh as the user mode helper, and embeds it into the kernel. Currently, it overrides HOSTCC with CC to use the 'hostprogs' syntax. This hack should go away. [1]: https://mirrors.edge.kernel.org/pub/tools/crosstool/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sam Ravnborg <sam@ravnborg.org>
2020-04-29 03:45:14 +00:00
# make the checker run with the right architecture
CHECKFLAGS += --arch=$(ARCH)
# insure the checker run with the right endianness
CHECKFLAGS += $(if $(CONFIG_CPU_BIG_ENDIAN),-mbig-endian,-mlittle-endian)
# the checker needs the correct machine size
CHECKFLAGS += $(if $(CONFIG_64BIT),-m64,-m32)
# Default kernel image to build when no specific target is given.
# KBUILD_IMAGE may be overruled on the command line or
# set in the environment
# Also any assignments in arch/$(ARCH)/Makefile take precedence over
# this default value
export KBUILD_IMAGE ?= vmlinux
#
# INSTALL_PATH specifies where to place the updated kernel and system map
# images. Default is /boot, but you can set it to other values
export INSTALL_PATH ?= /boot
kbuild: dtbs_install: new make target Unlike other build products in the Linux kernel, there is no 'make *install' mechanism to put devicetree blobs in a standard place. This commit adds a new 'dtbs_install' make target which copies all of the dtbs into the INSTALL_DTBS_PATH directory. INSTALL_DTBS_PATH can be set before calling make to change the default install directory. If not set then it defaults to: $INSTALL_PATH/dtbs/$KERNELRELEASE. This is done to keep dtbs from different kernel versions separate until things have settled down. Once the dtbs are stable, and not so strongly linked to the kernel version, the devicetree files will most likely move to their own repo. Users will need to upgrade install scripts at that time. v7: (reworked by Grant Likely) - Moved rules from arch/arm/Makefile to arch/arm/boot/dts/Makefile so that each dtb install could have a separate target and be reported as part of the make output. - Fixed dependency problem to ensure $KERNELRELEASE is calculated before attempting to install - Removed option to call external script. Copying the files should be sufficient and a build system can post-process the install directory. Despite the fact an external script is used for installing the kernel, I don't think that is a pattern that should be encouraged. I would rather see buildroot type tools post process the install directory to rename or move dtb files after installing to a staging directory. - Plus it is easy to add a hook after the fact without blocking the rest of this feature. - Move the helper targets into scripts/Makefile.lib with the rest of the common dtb rules Signed-off-by: Jason Cooper <jason@lakedaemon.net> Signed-off-by: Grant Likely <grant.likely@linaro.org> Cc: Michal Marek <mmarek@suse.cz> Cc: Russell King <linux@arm.linux.org.uk> Cc: Rob Herring <robh+dt@kernel.org>
2013-12-01 23:56:28 +00:00
#
# INSTALL_DTBS_PATH specifies a prefix for relocations required by build roots.
# Like INSTALL_MOD_PATH, it isn't defined in the Makefile, but can be passed as
# an argument if needed. Otherwise it defaults to the kernel install path
#
export INSTALL_DTBS_PATH ?= $(INSTALL_PATH)/dtbs/$(KERNELRELEASE)
#
# INSTALL_MOD_PATH specifies a prefix to MODLIB for module directory
# relocations required by build roots. This is not defined in the
# makefile but the argument can be passed to make if needed.
#
MODLIB = $(INSTALL_MOD_PATH)/lib/modules/$(KERNELRELEASE)
export MODLIB
kbuild: mark prepare0 as PHONY to fix external module build Commit c3ff2a5193fa ("powerpc/32: add stack protector support") caused kernel panic on PowerPC when an external module is used with CONFIG_STACKPROTECTOR because the 'prepare' target was not executed for the external module build. Commit e07db28eea38 ("kbuild: fix single target build for external module") turned it into a build error because the 'prepare' target is now executed but the 'prepare0' target is missing for the external module build. External module on arm/arm64 with CONFIG_STACKPROTECTOR_PER_TASK is also broken in the same way. Move 'PHONY += prepare0' to the common place. GNU Make is fine with missing rule for phony targets. I also removed the comment which is wrong irrespective of this commit. I minimize the change so it can be easily backported to 4.20.x To fix v4.20, please backport e07db28eea38 ("kbuild: fix single target build for external module"), and then this commit. Link: https://bugzilla.kernel.org/show_bug.cgi?id=201891 Fixes: e07db28eea38 ("kbuild: fix single target build for external module") Fixes: c3ff2a5193fa ("powerpc/32: add stack protector support") Fixes: 189af4657186 ("ARM: smp: add support for per-task stack canaries") Fixes: 0a1213fa7432 ("arm64: enable per-task stack canaries") Cc: linux-stable <stable@vger.kernel.org> # v4.20 Reported-by: Samuel Holland <samuel@sholland.org> Reported-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com> Acked-by: Ard Biesheuvel <ard.biesheuvel@linaro.org> Tested-by: Alexey Kardashevskiy <aik@ozlabs.ru>
2019-01-15 07:19:00 +00:00
PHONY += prepare0
export extmod_prefix = $(if $(KBUILD_EXTMOD),$(KBUILD_EXTMOD)/)
export MODORDER := $(extmod_prefix)modules.order
export MODULES_NSDEPS := $(extmod_prefix)modules.nsdeps
ifeq ($(KBUILD_EXTMOD),)
build-dir := .
clean-dirs := $(sort . Documentation \
$(patsubst %/,%,$(filter %/, $(core-) \
$(drivers-) $(libs-))))
export ARCH_CORE := $(core-y)
export ARCH_LIB := $(filter %/, $(libs-y))
export ARCH_DRIVERS := $(drivers-y) $(drivers-m)
# Externally visible symbols (used by link-vmlinux.sh)
KBUILD_VMLINUX_OBJS := ./built-in.a
kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y Kbuild supports not only obj-y but also lib-y to list objects linked to vmlinux. The difference between them is that all the objects from obj-y are forcibly linked to vmlinux, whereas the objects from lib-y are linked as needed; if there is no user of a lib-y object, it is not linked. lib-y is intended to list utility functions that may be called from all over the place (and may be unused at all), but it is a problem for EXPORT_SYMBOL(). Even if there is no call-site in the vmlinux, we need to keep exported symbols for the use from loadable modules. Commit 7f2084fa55e6 ("[kbuild] handle exports in lib-y objects reliably") worked around it by linking a dummy object, lib-ksyms.o, which contains references to all the symbols exported from lib.a in that directory. It uses the linker script command, EXTERN. Unfortunately, the meaning of EXTERN of ld.lld is different from that of ld.bfd. Therefore, this does not work with LD=ld.lld (CBL issue #515). Anyway, the build rule of lib-ksyms.o is somewhat tricky. So, I want to get rid of it. At first, I was thinking of accumulating lib-y objects into obj-y (or even replacing lib-y with obj-y entirely), but the lib-y syntax is used beyond the ordinary use in lib/ and arch/*/lib/. Examples: - drivers/firmware/efi/libstub/Makefile builds lib.a, which is linked into vmlinux in the own way (arm64), or linked to the decompressor (arm, x86). - arch/alpha/lib/Makefile builds lib.a which is linked not only to vmlinux, but also to bootloaders in arch/alpha/boot/Makefile. - arch/xtensa/boot/lib/Makefile builds lib.a for use from arch/xtensa/boot/boot-redboot/Makefile. One more thing, adding everything to obj-y would increase the vmlinux size of allnoconfig (or tinyconfig). For less impact, I tweaked the destination of lib.a at the top Makefile; when CONFIG_MODULES=y, lib.a goes to KBUILD_VMLINUX_OBJS, which is forcibly linked to vmlinux, otherwise lib.a goes to KBUILD_VMLINUX_LIBS as before. The size impact for normal usecases is quite small since at lease one symbol in every lib-y object is eventually called by someone. In case you are intrested, here are the figures. x86_64_defconfig: text data bss dec hex filename 19566602 5422072 1589328 26578002 1958c52 vmlinux.before 19566932 5422104 1589328 26578364 1958dbc vmlinux.after The case with the biggest impact is allnoconfig + CONFIG_MODULES=y. ARCH=x86 allnoconfig + CONFIG_MODULES=y: text data bss dec hex filename 1175162 254740 1220608 2650510 28718e vmlinux.before 1177974 254836 1220608 2653418 287cea vmlinux.after Hopefully this is still not a big deal. The per-file trimming with the static library is not so effective after all. If fine-grained optimization is desired, some architectures support CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, which trims dead code per-symbol basis. When LTO is supported in mainline, even better optimization will be possible. Link: https://github.com/ClangBuiltLinux/linux/issues/515 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-03-11 22:37:25 +00:00
ifdef CONFIG_MODULES
KBUILD_VMLINUX_OBJS += $(patsubst %/, %/lib.a, $(filter %/, $(libs-y)))
KBUILD_VMLINUX_LIBS := $(filter-out %/, $(libs-y))
kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y Kbuild supports not only obj-y but also lib-y to list objects linked to vmlinux. The difference between them is that all the objects from obj-y are forcibly linked to vmlinux, whereas the objects from lib-y are linked as needed; if there is no user of a lib-y object, it is not linked. lib-y is intended to list utility functions that may be called from all over the place (and may be unused at all), but it is a problem for EXPORT_SYMBOL(). Even if there is no call-site in the vmlinux, we need to keep exported symbols for the use from loadable modules. Commit 7f2084fa55e6 ("[kbuild] handle exports in lib-y objects reliably") worked around it by linking a dummy object, lib-ksyms.o, which contains references to all the symbols exported from lib.a in that directory. It uses the linker script command, EXTERN. Unfortunately, the meaning of EXTERN of ld.lld is different from that of ld.bfd. Therefore, this does not work with LD=ld.lld (CBL issue #515). Anyway, the build rule of lib-ksyms.o is somewhat tricky. So, I want to get rid of it. At first, I was thinking of accumulating lib-y objects into obj-y (or even replacing lib-y with obj-y entirely), but the lib-y syntax is used beyond the ordinary use in lib/ and arch/*/lib/. Examples: - drivers/firmware/efi/libstub/Makefile builds lib.a, which is linked into vmlinux in the own way (arm64), or linked to the decompressor (arm, x86). - arch/alpha/lib/Makefile builds lib.a which is linked not only to vmlinux, but also to bootloaders in arch/alpha/boot/Makefile. - arch/xtensa/boot/lib/Makefile builds lib.a for use from arch/xtensa/boot/boot-redboot/Makefile. One more thing, adding everything to obj-y would increase the vmlinux size of allnoconfig (or tinyconfig). For less impact, I tweaked the destination of lib.a at the top Makefile; when CONFIG_MODULES=y, lib.a goes to KBUILD_VMLINUX_OBJS, which is forcibly linked to vmlinux, otherwise lib.a goes to KBUILD_VMLINUX_LIBS as before. The size impact for normal usecases is quite small since at lease one symbol in every lib-y object is eventually called by someone. In case you are intrested, here are the figures. x86_64_defconfig: text data bss dec hex filename 19566602 5422072 1589328 26578002 1958c52 vmlinux.before 19566932 5422104 1589328 26578364 1958dbc vmlinux.after The case with the biggest impact is allnoconfig + CONFIG_MODULES=y. ARCH=x86 allnoconfig + CONFIG_MODULES=y: text data bss dec hex filename 1175162 254740 1220608 2650510 28718e vmlinux.before 1177974 254836 1220608 2653418 287cea vmlinux.after Hopefully this is still not a big deal. The per-file trimming with the static library is not so effective after all. If fine-grained optimization is desired, some architectures support CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, which trims dead code per-symbol basis. When LTO is supported in mainline, even better optimization will be possible. Link: https://github.com/ClangBuiltLinux/linux/issues/515 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-03-11 22:37:25 +00:00
else
KBUILD_VMLINUX_LIBS := $(patsubst %/,%/lib.a, $(libs-y))
kbuild: link lib-y objects to vmlinux forcibly when CONFIG_MODULES=y Kbuild supports not only obj-y but also lib-y to list objects linked to vmlinux. The difference between them is that all the objects from obj-y are forcibly linked to vmlinux, whereas the objects from lib-y are linked as needed; if there is no user of a lib-y object, it is not linked. lib-y is intended to list utility functions that may be called from all over the place (and may be unused at all), but it is a problem for EXPORT_SYMBOL(). Even if there is no call-site in the vmlinux, we need to keep exported symbols for the use from loadable modules. Commit 7f2084fa55e6 ("[kbuild] handle exports in lib-y objects reliably") worked around it by linking a dummy object, lib-ksyms.o, which contains references to all the symbols exported from lib.a in that directory. It uses the linker script command, EXTERN. Unfortunately, the meaning of EXTERN of ld.lld is different from that of ld.bfd. Therefore, this does not work with LD=ld.lld (CBL issue #515). Anyway, the build rule of lib-ksyms.o is somewhat tricky. So, I want to get rid of it. At first, I was thinking of accumulating lib-y objects into obj-y (or even replacing lib-y with obj-y entirely), but the lib-y syntax is used beyond the ordinary use in lib/ and arch/*/lib/. Examples: - drivers/firmware/efi/libstub/Makefile builds lib.a, which is linked into vmlinux in the own way (arm64), or linked to the decompressor (arm, x86). - arch/alpha/lib/Makefile builds lib.a which is linked not only to vmlinux, but also to bootloaders in arch/alpha/boot/Makefile. - arch/xtensa/boot/lib/Makefile builds lib.a for use from arch/xtensa/boot/boot-redboot/Makefile. One more thing, adding everything to obj-y would increase the vmlinux size of allnoconfig (or tinyconfig). For less impact, I tweaked the destination of lib.a at the top Makefile; when CONFIG_MODULES=y, lib.a goes to KBUILD_VMLINUX_OBJS, which is forcibly linked to vmlinux, otherwise lib.a goes to KBUILD_VMLINUX_LIBS as before. The size impact for normal usecases is quite small since at lease one symbol in every lib-y object is eventually called by someone. In case you are intrested, here are the figures. x86_64_defconfig: text data bss dec hex filename 19566602 5422072 1589328 26578002 1958c52 vmlinux.before 19566932 5422104 1589328 26578364 1958dbc vmlinux.after The case with the biggest impact is allnoconfig + CONFIG_MODULES=y. ARCH=x86 allnoconfig + CONFIG_MODULES=y: text data bss dec hex filename 1175162 254740 1220608 2650510 28718e vmlinux.before 1177974 254836 1220608 2653418 287cea vmlinux.after Hopefully this is still not a big deal. The per-file trimming with the static library is not so effective after all. If fine-grained optimization is desired, some architectures support CONFIG_LD_DEAD_CODE_DATA_ELIMINATION, which trims dead code per-symbol basis. When LTO is supported in mainline, even better optimization will be possible. Link: https://github.com/ClangBuiltLinux/linux/issues/515 Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reported-by: kbuild test robot <lkp@intel.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
2020-03-11 22:37:25 +00:00
endif
export KBUILD_VMLINUX_LIBS
export KBUILD_LDS := arch/$(SRCARCH)/kernel/vmlinux.lds
ifdef CONFIG_TRIM_UNUSED_KSYMS
# For the kernel to actually contain only the needed exported symbols,
# we have to build modules as well to determine what those symbols are.
KBUILD_MODULES := 1
endif
# '$(AR) mPi' needs 'T' to workaround the bug of llvm-ar <= 14
quiet_cmd_ar_vmlinux.a = AR $@
cmd_ar_vmlinux.a = \
rm -f $@; \
$(AR) cDPrST $@ $(KBUILD_VMLINUX_OBJS); \
$(AR) mPiT $$($(AR) t $@ | sed -n 1p) $@ $$($(AR) t $@ | grep -F -f $(srctree)/scripts/head-object-list.txt)
targets += vmlinux.a
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-06-11 15:50:57 +00:00
vmlinux.a: $(KBUILD_VMLINUX_OBJS) scripts/head-object-list.txt FORCE
$(call if_changed,ar_vmlinux.a)
PHONY += vmlinux_o
vmlinux_o: vmlinux.a $(KBUILD_VMLINUX_LIBS)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux_o
vmlinux.o modules.builtin.modinfo modules.builtin: vmlinux_o
@:
PHONY += vmlinux
kbuild: export top-level LDFLAGS_vmlinux only to scripts/Makefile.vmlinux Nathan Chancellor reports that $(NM) emits an error message when GNU Make 4.4 is used to build the ARM zImage. $ make-4.4 ARCH=arm CROSS_COMPILE=arm-linux-gnueabi- O=build defconfig zImage [snip] LD vmlinux NM System.map SORTTAB vmlinux OBJCOPY arch/arm/boot/Image Kernel: arch/arm/boot/Image is ready arm-linux-gnueabi-nm: 'arch/arm/boot/compressed/../../../../vmlinux': No such file /bin/sh: 1: arithmetic expression: expecting primary: " " LDS arch/arm/boot/compressed/vmlinux.lds AS arch/arm/boot/compressed/head.o GZIP arch/arm/boot/compressed/piggy_data AS arch/arm/boot/compressed/piggy.o CC arch/arm/boot/compressed/misc.o This occurs since GNU Make commit 98da874c4303 ("[SV 10593] Export variables to $(shell ...) commands"), and the O= option is needed to reproduce it. The generated zImage is correct despite the error message. As the commit description of 98da874c4303 [1] says, exported variables are passed down to $(shell ) functions, which means exported recursive variables might be expanded earlier than before, in the parse stage. The following test code demonstrates the change for GNU Make 4.4. [Test Makefile] $(shell echo hello > foo) export foo = $(shell cat bar/../foo) $(shell mkdir bar) all: @echo $(foo) [GNU Make 4.3] $ rm -rf bar; make-4.3 hello [GNU Make 4.4] $ rm -rf bar; make-4.4 cat: bar/../foo: No such file or directory hello The 'foo' is a resursively expanded (i.e. lazily expanded) variable. GNU Make 4.3 expands 'foo' just before running the recipe '@echo $(foo)', at this point, the directory 'bar' exists. GNU Make 4.4 expands 'foo' to evaluate $(shell mkdir bar) because it is exported. At this point, the directory 'bar' does not exit yet. The cat command cannot resolve the bar/../foo path, hence the error message. Let's get back to the kernel Makefile. In arch/arm/boot/compressed/Makefile, KBSS_SZ is referenced by LDFLAGS_vmlinux, which is recursive and also exported by the top Makefile. GNU Make 4.3 expands KBSS_SZ just before running the recipes, so no error message. GNU Make 4.4 expands KBSS_SZ in the parse stage, where the directory arm/arm/boot/compressed does not exit yet. When compiled with O=, the output directory is created by $(shell mkdir -p $(obj-dirs)) in scripts/Makefile.build. There are two ways to fix this particular issue: - change "$(obj)/../../../../vmlinux" in KBSS_SZ to "vmlinux" - unexport LDFLAGS_vmlinux This commit takes the latter course because it is what I originally intended. Commit 3ec8a5b33dea ("kbuild: do not export LDFLAGS_vmlinux") unexported LDFLAGS_vmlinux. Commit 5d4aeffbf709 ("kbuild: rebuild .vmlinux.export.o when its prerequisite is updated") accidentally exported it again. We can clean up arch/arm/boot/compressed/Makefile later. [1]: https://git.savannah.gnu.org/cgit/make.git/commit/?id=98da874c43035a490cdca81331724f233a3d0c9a Link: https://lore.kernel.org/all/Y7i8+EjwdnhHtlrr@dev-arch.thelio-3990X/ Fixes: 5d4aeffbf709 ("kbuild: rebuild .vmlinux.export.o when its prerequisite is updated") Reported-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Tested-by: Nathan Chancellor <nathan@kernel.org>
2023-01-08 19:23:17 +00:00
# LDFLAGS_vmlinux in the top Makefile defines linker flags for the top vmlinux,
# not for decompressors. LDFLAGS_vmlinux in arch/*/boot/compressed/Makefile is
# unrelated; the decompressors just happen to have the same base name,
# arch/*/boot/compressed/vmlinux.
# Export LDFLAGS_vmlinux only to scripts/Makefile.vmlinux.
#
# _LDFLAGS_vmlinux is a workaround for the 'private export' bug:
# https://savannah.gnu.org/bugs/?61463
# For Make > 4.4, the following simple code will work:
# vmlinux: private export LDFLAGS_vmlinux := $(LDFLAGS_vmlinux)
vmlinux: private _LDFLAGS_vmlinux := $(LDFLAGS_vmlinux)
vmlinux: export LDFLAGS_vmlinux = $(_LDFLAGS_vmlinux)
vmlinux: vmlinux.o $(KBUILD_LDS) modpost
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vmlinux
kbuild: let fixdep directly write to .*.cmd files Currently, fixdep writes dependencies to .*.tmp, which is renamed to .*.cmd after everything succeeds. This is a very safe way to avoid corrupted .*.cmd files. The if_changed_dep has carried this safety mechanism since it was added in 2002. If fixdep fails for some reasons or a user terminates the build while fixdep is running, the incomplete output from the fixdep could be troublesome. This is my insight about some bad scenarios: [1] If the compiler succeeds to generate *.o file, but fixdep fails to write necessary dependencies to .*.cmd file, Make will miss to rebuild the object when headers or CONFIG options are changed. In this case, fixdep should not generate .*.cmd file at all so that 'arg-check' will surely trigger the rebuild of the object. [2] A partially constructed .*.cmd file may not be a syntactically correct makefile. The next time Make runs, it would include it, then fail to parse it. Once this happens, 'make clean' is be the only way to fix it. In fact, [1] is no longer a problem since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"). Make deletes a target file on any failure in its recipe. Because fixdep is a part of the recipe of *.o target, if it fails, the *.o is deleted anyway. However, I am a bit worried about the slight possibility of [2]. So, here is a solution. Let fixdep directly write to a .*.cmd file, but allow makefiles to include it only when its corresponding target exists. This effectively reverts commit 2982c953570b ("kbuild: remove redundant $(wildcard ...) for cmd_files calculation"), and commit 00d78ab2ba75 ("kbuild: remove dead code in cmd_files calculation in top Makefile") because now we must check the presence of targets. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-11-30 01:05:22 +00:00
# The actual objects are generated when descending,
# make sure no implicit rule kicks in
$(sort $(KBUILD_LDS) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS)): . ;
ifeq ($(origin KERNELRELEASE),file)
filechk_kernel.release = $(srctree)/scripts/setlocalversion $(srctree)
else
filechk_kernel.release = echo $(KERNELRELEASE)
endif
# Store (new) KERNELRELEASE string in include/config/kernel.release
include/config/kernel.release: FORCE
$(call filechk,kernel.release)
# Additional helpers built in scripts/
# Carefully list dependencies so we do not try to build scripts twice
# in parallel
PHONY += scripts
scripts: scripts_basic scripts_dtc
$(Q)$(MAKE) $(build)=$(@)
# Things we need to do before we recursively start building the kernel
# or the modules are listed in "prepare".
# A multi level approach is used. prepareN is processed before prepareN-1.
# archprepare is used in arch Makefiles and when processed asm symlink,
# version.h and scripts_basic is processed / created.
PHONY += prepare archprepare
archprepare: outputmakefile archheaders archscripts scripts include/config/kernel.release \
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-06-11 15:50:57 +00:00
asm-generic $(version_h) include/generated/utsrelease.h \
include/generated/compile.h include/generated/autoconf.h remove-stale-files
kbuild: fix UML build error with CONFIG_GCC_PLUGINS UML fails to build with CONFIG_GCC_PLUGINS=y. $ make -s ARCH=um mrproper $ make -s ARCH=um allmodconfig $ make ARCH=um UPD include/generated/uapi/linux/version.h WRAP arch/x86/include/generated/uapi/asm/bpf_perf_event.h WRAP arch/x86/include/generated/uapi/asm/poll.h WRAP arch/x86/include/generated/asm/dma-contiguous.h WRAP arch/x86/include/generated/asm/early_ioremap.h WRAP arch/x86/include/generated/asm/export.h WRAP arch/x86/include/generated/asm/mcs_spinlock.h WRAP arch/x86/include/generated/asm/mm-arch-hooks.h SYSTBL arch/x86/include/generated/asm/syscalls_32.h SYSHDR arch/x86/include/generated/asm/unistd_32_ia32.h SYSHDR arch/x86/include/generated/asm/unistd_64_x32.h SYSTBL arch/x86/include/generated/asm/syscalls_64.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_32.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_64.h SYSHDR arch/x86/include/generated/uapi/asm/unistd_x32.h HOSTCC scripts/unifdef CC arch/x86/um/user-offsets.s cc1: error: cannot load plugin ./scripts/gcc-plugins/cyc_complexity_plugin.so ./scripts/gcc-plugins/cyc_complexity_plugin.so: cannot open shared object file: No such file or directory cc1: error: cannot load plugin ./scripts/gcc-plugins/structleak_plugin.so ./scripts/gcc-plugins/structleak_plugin.so: cannot open shared object file: No such file or directory cc1: error: cannot load plugin ./scripts/gcc-plugins/latent_entropy_plugin.so ./scripts/gcc-plugins/latent_entropy_plugin.so: cannot open shared object file: No such file or directory cc1: error: cannot load plugin ./scripts/gcc-plugins/randomize_layout_plugin.so ./scripts/gcc-plugins/randomize_layout_plugin.so: cannot open shared object file: No such file or directory make[1]: *** [scripts/Makefile.build;119: arch/x86/um/user-offsets.s] Error 1 make: *** [arch/um/Makefile;152: arch/x86/um/user-offsets.s] Error 2 Reorder the preparation stage (with cleanups) to make sure gcc-plugins is built before descending to arch/x86/um/. Fixes: 6b90bd4ba40b ("GCC plugin infrastructure") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-11-29 02:58:50 +00:00
prepare0: archprepare
$(Q)$(MAKE) $(build)=scripts/mod
$(Q)$(MAKE) $(build)=. prepare
# All the preparing..
kbuild: remove libelf checks from top Makefile I do not see a good reason why only the libelf development package must be so carefully checked. Kbuild generally does not check host tools or libraries. For example, x86_64 defconfig fails to build with no libssl development package installed. scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory 21 | #include <openssl/bio.h> | ^~~~~~~~~~~~~~~ To solve the build error, you need to install libssl-dev or openssl-devel package, depending on your distribution. 'apt-file search', 'dnf provides', etc. is your frined to find a proper package to install. This commit removes all the libelf checks from the top Makefile. If libelf is missing, objtool will fail to build in a similar pattern: .../linux/tools/objtool/include/objtool/elf.h:10:10: fatal error: gelf.h: No such file or directory 10 | #include <gelf.h> You need to install libelf-dev, libelf-devel, or elfutils-libelf-devel to proceed. Another remarkable change is, CONFIG_STACK_VALIDATION (without CONFIG_UNWINDER_ORC) previously continued to build with a warning, but now it will treat missing libelf as an error. This is just a one-time installation, so it should not hurt to break a build and make a user install the package. BTW, the traditional way to handle such checks is autotool, but according to [1], I do not expect the kernel build would have similar scripting like './configure' does. [1]: https://lore.kernel.org/lkml/CA+55aFzr2HTZVOuzpHYDwmtRJLsVzE-yqg2DHpHi_9ePsYp5ug@mail.gmail.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org>
2021-05-12 06:52:01 +00:00
prepare: prepare0
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
ifdef CONFIG_RUST
kbuild: mark `rustc` (and others) invocations as recursive `rustc` (like Cargo) may take advantage of the jobserver at any time (e.g. for backend parallelism, or eventually frontend too). In the kernel, we call `rustc` with `-Ccodegen-units=1` (and `-Zthreads` is 1 so far), so we do not expect parallelism. However, in the upcoming Rust 1.76.0, a warning is emitted by `rustc` [1] when it cannot connect to the jobserver it was passed (in many cases, but not all: compiling and `--print sysroot` do, but `--version` does not). And given GNU Make always passes the jobserver in the environment variable (even when a line is deemed non-recursive), `rustc` will end up complaining about it (in particular in Make 4.3 where there is only the simple pipe jobserver style). One solution is to remove the jobserver from `MAKEFLAGS`. However, we can mark the lines with calls to `rustc` (and Cargo) as recursive, which looks simpler. This is being documented as a recommendation in `rustc` [2] and allows us to be ready for the time we may use parallelism inside `rustc` (potentially now, if a user passes `-Zthreads`). Thus do so. Similarly, do the same for `rustdoc` and `cargo` calls. Finally, there is one case that the solution does not cover, which is the `$(shell ...)` call we have. Thus, for that one, set an empty `MAKEFLAGS` environment variable. Link: https://github.com/rust-lang/rust/issues/120515 [1] Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://github.com/rust-lang/rust/pull/121564 [2] Link: https://lore.kernel.org/r/20240217002638.57373-1-ojeda@kernel.org [ Reworded to add link to PR documenting the recommendation. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-02-17 00:26:37 +00:00
+$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
$(Q)$(MAKE) $(build)=rust
endif
PHONY += remove-stale-files
remove-stale-files:
$(Q)$(srctree)/scripts/remove-stale-files
# Support for using generic headers in asm-generic
asm-generic := -f $(srctree)/scripts/Makefile.asm-generic obj
PHONY += asm-generic uapi-asm-generic
asm-generic: uapi-asm-generic
$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/asm \
generic=include/asm-generic
uapi-asm-generic:
$(Q)$(MAKE) $(asm-generic)=arch/$(SRCARCH)/include/generated/uapi/asm \
generic=include/uapi/asm-generic
# Generate some files
# ---------------------------------------------------------------------------
# KERNELRELEASE can change from a few different places, meaning version.h
# needs to be updated, so this check is forced on all builds
uts_len := 64
define filechk_utsrelease.h
if [ `echo -n "$(KERNELRELEASE)" | wc -c ` -gt $(uts_len) ]; then \
echo '"$(KERNELRELEASE)" exceeds $(uts_len) characters' >&2; \
exit 1; \
fi; \
echo \#define UTS_RELEASE \"$(KERNELRELEASE)\"
endef
define filechk_version.h
if [ $(SUBLEVEL) -gt 255 ]; then \
echo \#define LINUX_VERSION_CODE $(shell \
expr $(VERSION) \* 65536 + $(PATCHLEVEL) \* 256 + 255); \
else \
echo \#define LINUX_VERSION_CODE $(shell \
expr $(VERSION) \* 65536 + $(PATCHLEVEL) \* 256 + $(SUBLEVEL)); \
fi; \
echo '#define KERNEL_VERSION(a,b,c) (((a) << 16) + ((b) << 8) + \
((c) > 255 ? 255 : (c)))'; \
echo \#define LINUX_VERSION_MAJOR $(VERSION); \
echo \#define LINUX_VERSION_PATCHLEVEL $(PATCHLEVEL); \
echo \#define LINUX_VERSION_SUBLEVEL $(SUBLEVEL)
endef
kbuild: add 'private' to target-specific variables Currently, Kbuild produces inconsistent results in some cases. You can do an interesting experiment using the --shuffle option, which is supported by GNU Make 4.4 or later. Set CONFIG_KVM_INTEL=y and CONFIG_KVM_AMD=m (or vice versa), and repeat incremental builds w/wo --shuffle=reverse. $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s $ make --shuffle=reverse [ snip ] CC [M] arch/x86/kvm/kvm-asm-offsets.s $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s arch/x86/kvm/kvm-asm-offsets.s is rebuilt every time w/wo the [M] marker. arch/x86/kvm/kvm-asm-offsets.s is built as built-in when it is built as a prerequisite of arch/x86/kvm/kvm-intel.o, which is built-in. arch/x86/kvm/kvm-asm-offsets.s is built as modular when it is built as a prerequisite of arch/x86/kvm/kvm-amd.o, which is a module. Another odd example is single target builds. When CONFIG_LKDTM=m, drivers/misc/lkdtm/rodata.o can be built as built-in or modular, depending on how it is built. $ make drivers/misc/lkdtm/lkdtm.o [ snip ] CC [M] drivers/misc/lkdtm/rodata.o $ make drivers/misc/lkdtm/rodata.o [ snip ] CC drivers/misc/lkdtm/rodata.o drivers/misc/lkdtm/rodata.o is built as modular when it is built as a prerequisite of another, but built as built-in when it is a final target. The same thing happens to drivers/memory/emif-asm-offsets.s when CONFIG_TI_EMIF_SRAM=m. $ make drivers/memory/ti-emif-sram.o [ snip ] CC [M] drivers/memory/emif-asm-offsets.s $ make drivers/memory/emif-asm-offsets.s [ snip ] CC drivers/memory/emif-asm-offsets.s This is because the part-of-module=y flag defined for the modules is inherited by its prerequisites. Target-specific variables are likely intended only for local use. This commit adds 'private' to them. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-04-27 15:32:53 +00:00
$(version_h): private PATCHLEVEL := $(or $(PATCHLEVEL), 0)
$(version_h): private SUBLEVEL := $(or $(SUBLEVEL), 0)
$(version_h): FORCE
$(call filechk,version.h)
include/generated/utsrelease.h: include/config/kernel.release FORCE
$(call filechk,utsrelease.h)
filechk_compile.h = $(srctree)/scripts/mkcompile_h \
"$(UTS_MACHINE)" "$(CONFIG_CC_VERSION_TEXT)" "$(LD)"
include/generated/compile.h: FORCE
$(call filechk,compile.h)
PHONY += headerdep
headerdep:
$(Q)find $(srctree)/include/ -name '*.h' | xargs --max-args 1 \
$(srctree)/scripts/headerdep.pl -I$(srctree)/include
# ---------------------------------------------------------------------------
# Kernel headers
#Default location for installed headers
export INSTALL_HDR_PATH = $(objtree)/usr
kbuild: add 'headers' target to build up uapi headers in usr/include In Linux build system, build targets and installation targets are separated. Examples are: - 'make vmlinux' -> 'make install' - 'make modules' -> 'make modules_install' - 'make dtbs' -> 'make dtbs_install' - 'make vdso' -> 'make vdso_install' The intention is to run the build targets under the normal privilege, then the installation targets under the root privilege since we need the write permission to the system directories. We have 'make headers_install' but the corresponding 'make headers' stage does not exist. The purpose of headers_install is to provide the kernel interface to C library. So, nobody would try to install headers to /usr/include directly. If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run, some build artifacts in the kernel tree would be owned by root because some of uapi headers are generated by 'uapi-asm-generic', 'archheaders' targets. Anyway, I believe it makes sense to split the header installation into two stages. [1] 'make headers' Process headers in uapi directories by scripts/headers_install.sh and copy them to usr/include [2] 'make headers_install' Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include For the backward compatibility, 'headers_install' depends on 'headers'. Some samples expect uapi headers in usr/include. So, the 'headers' target is useful to build up them in the fixed location usr/include irrespective of INSTALL_HDR_PATH. Another benefit is to stop polluting the final destination with the time-stamp files '.install' and '.check'. Maybe you can see them in your toolchains. Lastly, my main motivation is to prepare for compile-testing uapi headers. To build something, we have to save an object and .*.cmd somewhere. The usr/include/ will be the work directory for that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-04 10:14:02 +00:00
quiet_cmd_headers_install = INSTALL $(INSTALL_HDR_PATH)/include
cmd_headers_install = \
mkdir -p $(INSTALL_HDR_PATH); \
rsync -mrl --include='*/' --include='*\.h' --exclude='*' \
usr/include $(INSTALL_HDR_PATH)
PHONY += headers_install
kbuild: add 'headers' target to build up uapi headers in usr/include In Linux build system, build targets and installation targets are separated. Examples are: - 'make vmlinux' -> 'make install' - 'make modules' -> 'make modules_install' - 'make dtbs' -> 'make dtbs_install' - 'make vdso' -> 'make vdso_install' The intention is to run the build targets under the normal privilege, then the installation targets under the root privilege since we need the write permission to the system directories. We have 'make headers_install' but the corresponding 'make headers' stage does not exist. The purpose of headers_install is to provide the kernel interface to C library. So, nobody would try to install headers to /usr/include directly. If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run, some build artifacts in the kernel tree would be owned by root because some of uapi headers are generated by 'uapi-asm-generic', 'archheaders' targets. Anyway, I believe it makes sense to split the header installation into two stages. [1] 'make headers' Process headers in uapi directories by scripts/headers_install.sh and copy them to usr/include [2] 'make headers_install' Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include For the backward compatibility, 'headers_install' depends on 'headers'. Some samples expect uapi headers in usr/include. So, the 'headers' target is useful to build up them in the fixed location usr/include irrespective of INSTALL_HDR_PATH. Another benefit is to stop polluting the final destination with the time-stamp files '.install' and '.check'. Maybe you can see them in your toolchains. Lastly, my main motivation is to prepare for compile-testing uapi headers. To build something, we have to save an object and .*.cmd somewhere. The usr/include/ will be the work directory for that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-04 10:14:02 +00:00
headers_install: headers
$(call cmd,headers_install)
kbuild: add 'headers' target to build up uapi headers in usr/include In Linux build system, build targets and installation targets are separated. Examples are: - 'make vmlinux' -> 'make install' - 'make modules' -> 'make modules_install' - 'make dtbs' -> 'make dtbs_install' - 'make vdso' -> 'make vdso_install' The intention is to run the build targets under the normal privilege, then the installation targets under the root privilege since we need the write permission to the system directories. We have 'make headers_install' but the corresponding 'make headers' stage does not exist. The purpose of headers_install is to provide the kernel interface to C library. So, nobody would try to install headers to /usr/include directly. If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run, some build artifacts in the kernel tree would be owned by root because some of uapi headers are generated by 'uapi-asm-generic', 'archheaders' targets. Anyway, I believe it makes sense to split the header installation into two stages. [1] 'make headers' Process headers in uapi directories by scripts/headers_install.sh and copy them to usr/include [2] 'make headers_install' Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include For the backward compatibility, 'headers_install' depends on 'headers'. Some samples expect uapi headers in usr/include. So, the 'headers' target is useful to build up them in the fixed location usr/include irrespective of INSTALL_HDR_PATH. Another benefit is to stop polluting the final destination with the time-stamp files '.install' and '.check'. Maybe you can see them in your toolchains. Lastly, my main motivation is to prepare for compile-testing uapi headers. To build something, we have to save an object and .*.cmd somewhere. The usr/include/ will be the work directory for that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-04 10:14:02 +00:00
PHONY += archheaders archscripts
hdr-inst := -f $(srctree)/scripts/Makefile.headersinst obj
kbuild: add 'headers' target to build up uapi headers in usr/include In Linux build system, build targets and installation targets are separated. Examples are: - 'make vmlinux' -> 'make install' - 'make modules' -> 'make modules_install' - 'make dtbs' -> 'make dtbs_install' - 'make vdso' -> 'make vdso_install' The intention is to run the build targets under the normal privilege, then the installation targets under the root privilege since we need the write permission to the system directories. We have 'make headers_install' but the corresponding 'make headers' stage does not exist. The purpose of headers_install is to provide the kernel interface to C library. So, nobody would try to install headers to /usr/include directly. If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run, some build artifacts in the kernel tree would be owned by root because some of uapi headers are generated by 'uapi-asm-generic', 'archheaders' targets. Anyway, I believe it makes sense to split the header installation into two stages. [1] 'make headers' Process headers in uapi directories by scripts/headers_install.sh and copy them to usr/include [2] 'make headers_install' Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include For the backward compatibility, 'headers_install' depends on 'headers'. Some samples expect uapi headers in usr/include. So, the 'headers' target is useful to build up them in the fixed location usr/include irrespective of INSTALL_HDR_PATH. Another benefit is to stop polluting the final destination with the time-stamp files '.install' and '.check'. Maybe you can see them in your toolchains. Lastly, my main motivation is to prepare for compile-testing uapi headers. To build something, we have to save an object and .*.cmd somewhere. The usr/include/ will be the work directory for that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-04 10:14:02 +00:00
PHONY += headers
headers: $(version_h) scripts_unifdef uapi-asm-generic archheaders archscripts
$(if $(filter um, $(SRCARCH)), $(error Headers not exportable for UML))
$(Q)$(MAKE) $(hdr-inst)=include/uapi
$(Q)$(MAKE) $(hdr-inst)=arch/$(SRCARCH)/include/uapi
ifdef CONFIG_HEADERS_INSTALL
kbuild: add 'headers' target to build up uapi headers in usr/include In Linux build system, build targets and installation targets are separated. Examples are: - 'make vmlinux' -> 'make install' - 'make modules' -> 'make modules_install' - 'make dtbs' -> 'make dtbs_install' - 'make vdso' -> 'make vdso_install' The intention is to run the build targets under the normal privilege, then the installation targets under the root privilege since we need the write permission to the system directories. We have 'make headers_install' but the corresponding 'make headers' stage does not exist. The purpose of headers_install is to provide the kernel interface to C library. So, nobody would try to install headers to /usr/include directly. If 'sudo make INSTALL_HDR_PATH=/usr/include headers_install' were run, some build artifacts in the kernel tree would be owned by root because some of uapi headers are generated by 'uapi-asm-generic', 'archheaders' targets. Anyway, I believe it makes sense to split the header installation into two stages. [1] 'make headers' Process headers in uapi directories by scripts/headers_install.sh and copy them to usr/include [2] 'make headers_install' Copy '*.h' verbatim from usr/include to $(INSTALL_HDR_PATH)/include For the backward compatibility, 'headers_install' depends on 'headers'. Some samples expect uapi headers in usr/include. So, the 'headers' target is useful to build up them in the fixed location usr/include irrespective of INSTALL_HDR_PATH. Another benefit is to stop polluting the final destination with the time-stamp files '.install' and '.check'. Maybe you can see them in your toolchains. Lastly, my main motivation is to prepare for compile-testing uapi headers. To build something, we have to save an object and .*.cmd somewhere. The usr/include/ will be the work directory for that. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2019-06-04 10:14:02 +00:00
prepare: headers
endif
PHONY += scripts_unifdef
scripts_unifdef: scripts_basic
$(Q)$(MAKE) $(build)=scripts scripts/unifdef
# ---------------------------------------------------------------------------
# Install
# Many distributions have the custom install script, /sbin/installkernel.
# If DKMS is installed, 'make install' will eventually recurse back
# to this Makefile to build and install external modules.
# Cancel sub_make_done so that options such as M=, V=, etc. are parsed.
quiet_cmd_install = INSTALL $(INSTALL_PATH)
cmd_install = unset sub_make_done; $(srctree)/scripts/install.sh
kbuild: unify vdso_install rules Currently, there is no standard implementation for vdso_install, leading to various issues: 1. Code duplication Many architectures duplicate similar code just for copying files to the install destination. Some architectures (arm, sparc, x86) create build-id symlinks, introducing more code duplication. 2. Unintended updates of in-tree build artifacts The vdso_install rule depends on the vdso files to install. It may update in-tree build artifacts. This can be problematic, as explained in commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux"). 3. Broken code in some architectures Makefile code is often copied from one architecture to another without proper adaptation. 'make vdso_install' for parisc does not work. 'make vdso_install' for s390 installs vdso64, but not vdso32. To address these problems, this commit introduces a generic vdso_install rule. Architectures that support vdso_install need to define vdso-install-y in arch/*/Makefile. vdso-install-y lists the files to install. For example, arch/x86/Makefile looks like this: vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg vdso-install-$(CONFIG_X86_32) += arch/x86/entry/vdso/vdso32.so.dbg vdso-install-$(CONFIG_IA32_EMULATION) += arch/x86/entry/vdso/vdso32.so.dbg These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix, if exists, stripped away. vdso-install-y can optionally take the second field after the colon separator. This is needed because some architectures install a vdso file as a different base name. The following is a snippet from arch/arm64/Makefile. vdso-install-$(CONFIG_COMPAT_VDSO) += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so This will rename vdso.so.dbg to vdso32.so during installation. If such architectures change their implementation so that the base names match, this workaround will go away. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390 Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Guo Ren <guoren@kernel.org> Acked-by: Helge Deller <deller@gmx.de> # parisc Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2023-10-14 10:54:35 +00:00
# ---------------------------------------------------------------------------
# vDSO install
PHONY += vdso_install
vdso_install: export INSTALL_FILES = $(vdso-install-y)
vdso_install:
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.vdsoinst
# ---------------------------------------------------------------------------
# Tools
ifdef CONFIG_OBJTOOL
kbuild: remove libelf checks from top Makefile I do not see a good reason why only the libelf development package must be so carefully checked. Kbuild generally does not check host tools or libraries. For example, x86_64 defconfig fails to build with no libssl development package installed. scripts/extract-cert.c:21:10: fatal error: openssl/bio.h: No such file or directory 21 | #include <openssl/bio.h> | ^~~~~~~~~~~~~~~ To solve the build error, you need to install libssl-dev or openssl-devel package, depending on your distribution. 'apt-file search', 'dnf provides', etc. is your frined to find a proper package to install. This commit removes all the libelf checks from the top Makefile. If libelf is missing, objtool will fail to build in a similar pattern: .../linux/tools/objtool/include/objtool/elf.h:10:10: fatal error: gelf.h: No such file or directory 10 | #include <gelf.h> You need to install libelf-dev, libelf-devel, or elfutils-libelf-devel to proceed. Another remarkable change is, CONFIG_STACK_VALIDATION (without CONFIG_UNWINDER_ORC) previously continued to build with a warning, but now it will treat missing libelf as an error. This is just a one-time installation, so it should not hurt to break a build and make a user install the package. BTW, the traditional way to handle such checks is autotool, but according to [1], I do not expect the kernel build would have similar scripting like './configure' does. [1]: https://lore.kernel.org/lkml/CA+55aFzr2HTZVOuzpHYDwmtRJLsVzE-yqg2DHpHi_9ePsYp5ug@mail.gmail.com/ Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Andrii Nakryiko <andrii@kernel.org>
2021-05-12 06:52:01 +00:00
prepare: tools/objtool
endif
ifdef CONFIG_BPF
ifdef CONFIG_DEBUG_INFO_BTF
prepare: tools/bpf/resolve_btfids
endif
endif
PHONY += resolve_btfids_clean
resolve_btfids_O = $(abspath $(objtree))/tools/bpf/resolve_btfids
# tools/bpf/resolve_btfids directory might not exist
# in output directory, skip its clean in that case
resolve_btfids_clean:
ifneq ($(wildcard $(resolve_btfids_O)),)
$(Q)$(MAKE) -sC $(srctree)/tools/bpf/resolve_btfids O=$(resolve_btfids_O) clean
endif
# Clear a bunch of variables before executing the submake
ifeq ($(quiet),silent_)
tools_silent=s
endif
tools/: FORCE
$(Q)mkdir -p $(objtree)/tools
$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/
tools/%: FORCE
$(Q)mkdir -p $(objtree)/tools
$(Q)$(MAKE) LDFLAGS= MAKEFLAGS="$(tools_silent) $(filter --j% -j,$(MAKEFLAGS))" O=$(abspath $(objtree)) subdir=tools -C $(srctree)/tools/ $*
# ---------------------------------------------------------------------------
# Kernel selftest
PHONY += kselftest
kselftest: headers
$(Q)$(MAKE) -C $(srctree)/tools/testing/selftests run_tests
kselftest-%: headers FORCE
$(Q)$(MAKE) -C $(srctree)/tools/testing/selftests $*
PHONY += kselftest-merge
kselftest-merge:
$(if $(wildcard $(objtree)/.config),, $(error No .config exists, config your kernel first!))
$(Q)find $(srctree)/tools/testing/selftests -name config -o -name config.$(UTS_MACHINE) | \
xargs $(srctree)/scripts/kconfig/merge_config.sh -y -m $(objtree)/.config
$(Q)$(MAKE) -f $(srctree)/Makefile olddefconfig
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
# ---------------------------------------------------------------------------
# Devicetree files
ifneq ($(wildcard $(srctree)/arch/$(SRCARCH)/boot/dts/),)
dtstree := arch/$(SRCARCH)/boot/dts
endif
ifneq ($(dtstree),)
%.dtb: dtbs_prepare
$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
%.dtbo: dtbs_prepare
$(Q)$(MAKE) $(build)=$(dtstree) $(dtstree)/$@
PHONY += dtbs dtbs_prepare dtbs_install dtbs_check
dtbs: dtbs_prepare
$(Q)$(MAKE) $(build)=$(dtstree) need-dtbslist=1
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
# include/config/kernel.release is actually needed when installing DTBs because
# INSTALL_DTBS_PATH contains $(KERNELRELEASE). However, we do not want to make
# dtbs_install depend on it as dtbs_install may run as root.
dtbs_prepare: include/config/kernel.release scripts_dtc
ifneq ($(filter dtbs_check, $(MAKECMDGOALS)),)
export CHECK_DTBS=y
endif
ifneq ($(CHECK_DTBS),)
dtbs_prepare: dt_binding_schemas
kbuild: avoid concurrency issue in parallel building dtbs and dtbs_check 'make dtbs_check' checks the shecma in addition to building *.dtb files, in other words, 'make dtbs_check' is a super-set of 'make dtbs'. So, you do not have to do 'make dtbs dtbs_check', but I want to keep the build system as robust as possible in any use. Currently, 'dtbs' and 'dtbs_check' are independent of each other. In parallel building, two threads descend into arch/*/boot/dts/, one for dtbs and the other for dtbs_check, then end up with building the same DTB simultaneously. This commit fixes the concurrency issue. Otherwise, I see build errors like follows: $ make ARCH=arm64 defconfig $ make -j16 ARCH=arm64 DT_SCHEMA_FILES=Documentation/devicetree/bindings/arm/psci.yaml dtbs dtbs_check <snip> DTC arch/arm64/boot/dts/qcom/sdm845-cheza-r2.dtb DTC arch/arm64/boot/dts/amlogic/meson-gxl-s905x-p212.dtb DTC arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb DTC arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb DTC arch/arm64/boot/dts/freescale/imx8mn-evk.dtb DTC arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb DTC arch/arm64/boot/dts/zte/zx296718-pcbox.dtb DTC arch/arm64/boot/dts/altera/socfpga_stratix10_socdk.dt.yaml DTC arch/arm64/boot/dts/amlogic/meson-gxl-s905d-p230.dtb DTC arch/arm64/boot/dts/xilinx/zynqmp-zc1254-revA.dtb DTC arch/arm64/boot/dts/allwinner/sun50i-h6-pine-h64.dtb DTC arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet-inx.dtb DTC arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb CHECK arch/arm64/boot/dts/altera/socfpga_stratix10_socdk.dt.yaml fixdep: error opening file: arch/arm64/boot/dts/allwinner/.sun50i-h6-orangepi-lite2.dtb.d: No such file or directory make[2]: *** [scripts/Makefile.lib:296: arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb] Error 2 make[2]: *** Deleting file 'arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-lite2.dtb' make[2]: *** Waiting for unfinished jobs.... DTC arch/arm64/boot/dts/rockchip/rk3399-gru-scarlet-kd.dtb DTC arch/arm64/boot/dts/amlogic/meson-gxl-s905d-p231.dtb DTC arch/arm64/boot/dts/xilinx/zynqmp-zc1275-revA.dtb DTC arch/arm64/boot/dts/freescale/imx8mn-ddr4-evk.dtb fixdep: parse error; no targets found make[2]: *** [scripts/Makefile.lib:296: arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb] Error 1 make[2]: *** Deleting file 'arch/arm64/boot/dts/allwinner/sun50i-h6-orangepi-one-plus.dtb' make[1]: *** [scripts/Makefile.build:505: arch/arm64/boot/dts/allwinner] Error 2 make[1]: *** Waiting for unfinished jobs.... DTC arch/arm64/boot/dts/renesas/r8a77951-salvator-xs.dtb Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Rob Herring <robh@kernel.org>
2020-03-04 03:20:36 +00:00
endif
dtbs_check: dtbs
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
dtbs_install:
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.dtbinst obj=$(dtstree)
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
ifdef CONFIG_OF_EARLY_FLATTREE
all: dtbs
endif
endif
PHONY += scripts_dtc
scripts_dtc: scripts_basic
$(Q)$(MAKE) $(build)=scripts/dtc
ifneq ($(filter dt_binding_check, $(MAKECMDGOALS)),)
export CHECK_DTBS=y
endif
PHONY += dt_binding_check dt_binding_schemas
dt_binding_check: dt_binding_schemas scripts_dtc
$(Q)$(MAKE) $(build)=Documentation/devicetree/bindings $@
dt_binding_schemas:
$(Q)$(MAKE) $(build)=Documentation/devicetree/bindings
PHONY += dt_compatible_check
dt_compatible_check: dt_binding_schemas
$(Q)$(MAKE) $(build)=Documentation/devicetree/bindings $@
# ---------------------------------------------------------------------------
# Modules
ifdef CONFIG_MODULES
# By default, build modules as well
all: modules
# When we're building modules with modversions, we need to consider
# the built-in objects during the descend as well, in order to
# make sure the checksums are up to date before we record them.
ifdef CONFIG_MODVERSIONS
KBUILD_BUILTIN := 1
endif
# Build modules
#
# *.ko are usually independent of vmlinux, but CONFIG_DEBUG_INFO_BTF_MODULES
# is an exception.
ifdef CONFIG_DEBUG_INFO_BTF_MODULES
KBUILD_BUILTIN := 1
modules: vmlinux
endif
modules: modules_prepare
# Target to prepare building external modules
modules_prepare: prepare
$(Q)$(MAKE) $(build)=scripts scripts/module.lds
endif # CONFIG_MODULES
###
# Cleaning is done on three levels.
# make clean Delete most generated files
# Leave enough to build external modules
# make mrproper Delete the current configuration, and all generated files
# make distclean Remove editor backup files, patch leftover files and the like
# Directories & files removed with 'make clean'
CLEAN_FILES += vmlinux.symvers modules-only.symvers \
kbuild: wire up the build rule of compile_commands.json to Makefile Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-22 14:56:16 +00:00
modules.builtin modules.builtin.modinfo modules.nsdeps \
kbuild: Remove support for Clang's ThinLTO caching There is an issue in clang's ThinLTO caching (enabled for the kernel via '--thinlto-cache-dir') with .incbin, which the kernel occasionally uses to include data within the kernel, such as the .config file for /proc/config.gz. For example, when changing the .config and rebuilding vmlinux, the copy of .config in vmlinux does not match the copy of .config in the build folder: $ echo 'CONFIG_LTO_NONE=n CONFIG_LTO_CLANG_THIN=y CONFIG_IKCONFIG=y CONFIG_HEADERS_INSTALL=y' >kernel/configs/repro.config $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 clean defconfig repro.config vmlinux ... $ grep CONFIG_HEADERS_INSTALL .config CONFIG_HEADERS_INSTALL=y $ scripts/extract-ikconfig vmlinux | grep CONFIG_HEADERS_INSTALL CONFIG_HEADERS_INSTALL=y $ scripts/config -d HEADERS_INSTALL $ make -kj"$(nproc)" ARCH=x86_64 LLVM=1 vmlinux ... UPD kernel/config_data GZIP kernel/config_data.gz CC kernel/configs.o ... LD vmlinux ... $ grep CONFIG_HEADERS_INSTALL .config # CONFIG_HEADERS_INSTALL is not set $ scripts/extract-ikconfig vmlinux | grep CONFIG_HEADERS_INSTALL CONFIG_HEADERS_INSTALL=y Without '--thinlto-cache-dir' or when using full LTO, this issue does not occur. Benchmarking incremental builds on a few different machines with and without the cache shows a 20% increase in incremental build time without the cache when measured by touching init/main.c and running 'make all'. ARCH=arm64 defconfig + CONFIG_LTO_CLANG_THIN=y on an arm64 host: Benchmark 1: With ThinLTO cache Time (mean ± σ): 56.347 s ± 0.163 s [User: 83.768 s, System: 24.661 s] Range (min … max): 56.109 s … 56.594 s 10 runs Benchmark 2: Without ThinLTO cache Time (mean ± σ): 67.740 s ± 0.479 s [User: 718.458 s, System: 31.797 s] Range (min … max): 67.059 s … 68.556 s 10 runs Summary With ThinLTO cache ran 1.20 ± 0.01 times faster than Without ThinLTO cache ARCH=x86_64 defconfig + CONFIG_LTO_CLANG_THIN=y on an x86_64 host: Benchmark 1: With ThinLTO cache Time (mean ± σ): 85.772 s ± 0.252 s [User: 91.505 s, System: 8.408 s] Range (min … max): 85.447 s … 86.244 s 10 runs Benchmark 2: Without ThinLTO cache Time (mean ± σ): 103.833 s ± 0.288 s [User: 232.058 s, System: 8.569 s] Range (min … max): 103.286 s … 104.124 s 10 runs Summary With ThinLTO cache ran 1.21 ± 0.00 times faster than Without ThinLTO cache While it is unfortunate to take this performance improvement off the table, correctness is more important. If/when this is fixed in LLVM, it can potentially be brought back in a conditional manner. Alternatively, a developer can just disable LTO if doing incremental compiles quickly is important, as a full compile cycle can still take over a minute even with the cache and it is unlikely that LTO will result in functional differences for a kernel change. Cc: stable@vger.kernel.org Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Reported-by: Yifan Hong <elsk@google.com> Closes: https://github.com/ClangBuiltLinux/linux/issues/2021 Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Closes: https://lore.kernel.org/r/20220327115526.cc4b0ff55fc53c97683c3e4d@kernel.org/ Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-05-01 22:55:25 +00:00
compile_commands.json rust/test \
rust-project.json .vmlinux.objs .vmlinux.export.c
# Directories & files removed with 'make mrproper'
MRPROPER_FILES += include/config include/generated \
arch/$(SRCARCH)/include/generated .objdiff \
debian snap tar-install \
.config .config.old .version \
Module.symvers \
certs/signing_key.pem \
certs/x509.genkey \
vmlinux-gdb.py \
rpmbuild \
rust/libmacros.so
# clean - Delete most, but leave enough to build external modules
#
kbuild: add 'private' to target-specific variables Currently, Kbuild produces inconsistent results in some cases. You can do an interesting experiment using the --shuffle option, which is supported by GNU Make 4.4 or later. Set CONFIG_KVM_INTEL=y and CONFIG_KVM_AMD=m (or vice versa), and repeat incremental builds w/wo --shuffle=reverse. $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s $ make --shuffle=reverse [ snip ] CC [M] arch/x86/kvm/kvm-asm-offsets.s $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s arch/x86/kvm/kvm-asm-offsets.s is rebuilt every time w/wo the [M] marker. arch/x86/kvm/kvm-asm-offsets.s is built as built-in when it is built as a prerequisite of arch/x86/kvm/kvm-intel.o, which is built-in. arch/x86/kvm/kvm-asm-offsets.s is built as modular when it is built as a prerequisite of arch/x86/kvm/kvm-amd.o, which is a module. Another odd example is single target builds. When CONFIG_LKDTM=m, drivers/misc/lkdtm/rodata.o can be built as built-in or modular, depending on how it is built. $ make drivers/misc/lkdtm/lkdtm.o [ snip ] CC [M] drivers/misc/lkdtm/rodata.o $ make drivers/misc/lkdtm/rodata.o [ snip ] CC drivers/misc/lkdtm/rodata.o drivers/misc/lkdtm/rodata.o is built as modular when it is built as a prerequisite of another, but built as built-in when it is a final target. The same thing happens to drivers/memory/emif-asm-offsets.s when CONFIG_TI_EMIF_SRAM=m. $ make drivers/memory/ti-emif-sram.o [ snip ] CC [M] drivers/memory/emif-asm-offsets.s $ make drivers/memory/emif-asm-offsets.s [ snip ] CC drivers/memory/emif-asm-offsets.s This is because the part-of-module=y flag defined for the modules is inherited by its prerequisites. Target-specific variables are likely intended only for local use. This commit adds 'private' to them. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-04-27 15:32:53 +00:00
clean: private rm-files := $(CLEAN_FILES)
PHONY += archclean vmlinuxclean
vmlinuxclean:
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/link-vmlinux.sh clean
$(Q)$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) clean)
clean: archclean vmlinuxclean resolve_btfids_clean
# mrproper - Delete all generated files, including .config
#
kbuild: add 'private' to target-specific variables Currently, Kbuild produces inconsistent results in some cases. You can do an interesting experiment using the --shuffle option, which is supported by GNU Make 4.4 or later. Set CONFIG_KVM_INTEL=y and CONFIG_KVM_AMD=m (or vice versa), and repeat incremental builds w/wo --shuffle=reverse. $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s $ make --shuffle=reverse [ snip ] CC [M] arch/x86/kvm/kvm-asm-offsets.s $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s arch/x86/kvm/kvm-asm-offsets.s is rebuilt every time w/wo the [M] marker. arch/x86/kvm/kvm-asm-offsets.s is built as built-in when it is built as a prerequisite of arch/x86/kvm/kvm-intel.o, which is built-in. arch/x86/kvm/kvm-asm-offsets.s is built as modular when it is built as a prerequisite of arch/x86/kvm/kvm-amd.o, which is a module. Another odd example is single target builds. When CONFIG_LKDTM=m, drivers/misc/lkdtm/rodata.o can be built as built-in or modular, depending on how it is built. $ make drivers/misc/lkdtm/lkdtm.o [ snip ] CC [M] drivers/misc/lkdtm/rodata.o $ make drivers/misc/lkdtm/rodata.o [ snip ] CC drivers/misc/lkdtm/rodata.o drivers/misc/lkdtm/rodata.o is built as modular when it is built as a prerequisite of another, but built as built-in when it is a final target. The same thing happens to drivers/memory/emif-asm-offsets.s when CONFIG_TI_EMIF_SRAM=m. $ make drivers/memory/ti-emif-sram.o [ snip ] CC [M] drivers/memory/emif-asm-offsets.s $ make drivers/memory/emif-asm-offsets.s [ snip ] CC drivers/memory/emif-asm-offsets.s This is because the part-of-module=y flag defined for the modules is inherited by its prerequisites. Target-specific variables are likely intended only for local use. This commit adds 'private' to them. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-04-27 15:32:53 +00:00
mrproper: private rm-files := $(MRPROPER_FILES)
mrproper-dirs := $(addprefix _mrproper_,scripts)
PHONY += $(mrproper-dirs) mrproper
$(mrproper-dirs):
$(Q)$(MAKE) $(clean)=$(patsubst _mrproper_%,%,$@)
mrproper: clean $(mrproper-dirs)
$(call cmd,rmfiles)
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
@find . $(RCS_FIND_IGNORE) \
\( -name '*.rmeta' \) \
-type f -print | xargs rm -f
# distclean
#
PHONY += distclean
distclean: mrproper
@find . $(RCS_FIND_IGNORE) \
\( -name '*.orig' -o -name '*.rej' -o -name '*~' \
-o -name '*.bak' -o -name '#*#' -o -name '*%' \
-o -name 'core' -o -name tags -o -name TAGS -o -name 'cscope*' \
-o -name GPATH -o -name GRTAGS -o -name GSYMS -o -name GTAGS \) \
-type f -print | xargs rm -f
# Packaging of the kernel to various formats
# ---------------------------------------------------------------------------
%src-pkg: FORCE
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
%pkg: include/config/kernel.release FORCE
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.package $@
# Brief documentation of the typical targets used
# ---------------------------------------------------------------------------
boards := $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*_defconfig)
boards := $(sort $(notdir $(boards)))
board-dirs := $(dir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/*/*_defconfig))
board-dirs := $(sort $(notdir $(board-dirs:/=)))
PHONY += help
help:
@echo 'Cleaning targets:'
@echo ' clean - Remove most generated files but keep the config and'
@echo ' enough build support to build external modules'
@echo ' mrproper - Remove all generated files + config + various backup files'
@echo ' distclean - mrproper + remove editor backup and patch files'
@echo ''
@$(MAKE) -f $(srctree)/scripts/kconfig/Makefile help
@echo ''
@echo 'Other generic targets:'
@echo ' all - Build all targets marked with [*]'
@echo '* vmlinux - Build the bare kernel'
@echo '* modules - Build all modules'
@echo ' modules_install - Install all modules to INSTALL_MOD_PATH (default: /)'
kbuild: unify vdso_install rules Currently, there is no standard implementation for vdso_install, leading to various issues: 1. Code duplication Many architectures duplicate similar code just for copying files to the install destination. Some architectures (arm, sparc, x86) create build-id symlinks, introducing more code duplication. 2. Unintended updates of in-tree build artifacts The vdso_install rule depends on the vdso files to install. It may update in-tree build artifacts. This can be problematic, as explained in commit 19514fc665ff ("arm, kbuild: make "make install" not depend on vmlinux"). 3. Broken code in some architectures Makefile code is often copied from one architecture to another without proper adaptation. 'make vdso_install' for parisc does not work. 'make vdso_install' for s390 installs vdso64, but not vdso32. To address these problems, this commit introduces a generic vdso_install rule. Architectures that support vdso_install need to define vdso-install-y in arch/*/Makefile. vdso-install-y lists the files to install. For example, arch/x86/Makefile looks like this: vdso-install-$(CONFIG_X86_64) += arch/x86/entry/vdso/vdso64.so.dbg vdso-install-$(CONFIG_X86_X32_ABI) += arch/x86/entry/vdso/vdsox32.so.dbg vdso-install-$(CONFIG_X86_32) += arch/x86/entry/vdso/vdso32.so.dbg vdso-install-$(CONFIG_IA32_EMULATION) += arch/x86/entry/vdso/vdso32.so.dbg These files will be installed to $(MODLIB)/vdso/ with the .dbg suffix, if exists, stripped away. vdso-install-y can optionally take the second field after the colon separator. This is needed because some architectures install a vdso file as a different base name. The following is a snippet from arch/arm64/Makefile. vdso-install-$(CONFIG_COMPAT_VDSO) += arch/arm64/kernel/vdso32/vdso.so.dbg:vdso32.so This will rename vdso.so.dbg to vdso32.so during installation. If such architectures change their implementation so that the base names match, this workaround will go away. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Sven Schnelle <svens@linux.ibm.com> # s390 Reviewed-by: Nicolas Schier <nicolas@fjasle.eu> Reviewed-by: Guo Ren <guoren@kernel.org> Acked-by: Helge Deller <deller@gmx.de> # parisc Acked-by: Catalin Marinas <catalin.marinas@arm.com> Acked-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
2023-10-14 10:54:35 +00:00
@echo ' vdso_install - Install unstripped vdso to INSTALL_MOD_PATH (default: /)'
@echo ' dir/ - Build all files in dir and below'
@echo ' dir/file.[ois] - Build specified target only'
@echo ' dir/file.ll - Build the LLVM assembly file'
@echo ' (requires compiler support for LLVM assembly generation)'
@echo ' dir/file.lst - Build specified mixed source/assembly target only'
@echo ' (requires a recent binutils and recent build (System.map))'
@echo ' dir/file.ko - Build module including final link'
@echo ' modules_prepare - Set up for building external modules'
@echo ' tags/TAGS - Generate tags file for editors'
@echo ' cscope - Generate cscope index'
@echo ' gtags - Generate GNU GLOBAL index'
@echo ' kernelrelease - Output the release version string (use with make -s)'
@echo ' kernelversion - Output the version stored in Makefile (use with make -s)'
@echo ' image_name - Output the image name (use with make -s)'
@echo ' headers_install - Install sanitised kernel headers to INSTALL_HDR_PATH'; \
echo ' (default: $(INSTALL_HDR_PATH))'; \
echo ''
@echo 'Static analysers:'
@echo ' checkstack - Generate a list of stack hogs and consider all functions'
@echo ' with a stack size larger than MINSTACKSIZE (default: 100)'
@echo ' versioncheck - Sanity check on version.h usage'
@echo ' includecheck - Check for duplicate included header files'
@echo ' export_report - List the usages of all exported symbols'
@echo ' headerdep - Detect inclusion cycles in headers'
@echo ' coccicheck - Check with Coccinelle'
Makefile: Add clang-tidy and static analyzer support to makefile This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-22 14:56:18 +00:00
@echo ' clang-analyzer - Check with clang static analyzer'
@echo ' clang-tidy - Check with clang-tidy'
@echo ''
@echo 'Tools:'
@echo ' nsdeps - Generate missing symbol namespace dependencies'
@echo ''
@echo 'Kernel selftest:'
@echo ' kselftest - Build and run kernel selftest'
@echo ' Build, install, and boot kernel before'
@echo ' running kselftest on it'
@echo ' Run as root for full coverage'
@echo ' kselftest-all - Build kernel selftest'
@echo ' kselftest-install - Build and install kernel selftest'
@echo ' kselftest-clean - Remove all generated kselftest files'
@echo ' kselftest-merge - Merge all the config dependencies of'
@echo ' kselftest to existing .config.'
@echo ''
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
@echo 'Rust targets:'
@echo ' rustavailable - Checks whether the Rust toolchain is'
@echo ' available and, if not, explains why.'
@echo ' rustfmt - Reformat all the Rust code in the kernel'
@echo ' rustfmtcheck - Checks if all the Rust code in the kernel'
@echo ' is formatted, printing a diff otherwise.'
@echo ' rustdoc - Generate Rust documentation'
@echo ' (requires kernel .config)'
@echo ' rusttest - Runs the Rust tests'
@echo ' (requires kernel .config; downloads external repos)'
@echo ' rust-analyzer - Generate rust-project.json rust-analyzer support file'
@echo ' (requires kernel .config)'
@echo ' dir/file.[os] - Build specified target only'
@echo ' dir/file.rsi - Build macro expanded source, similar to C preprocessing.'
@echo ' Run with RUSTFMT=n to skip reformatting if needed.'
@echo ' The output is not intended to be compilable.'
@echo ' dir/file.ll - Build the LLVM assembly file'
@echo ''
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
@$(if $(dtstree), \
echo 'Devicetree:'; \
echo '* dtbs - Build device tree blobs for enabled boards'; \
echo ' dtbs_install - Install dtbs to $(INSTALL_DTBS_PATH)'; \
echo ' dt_binding_check - Validate device tree binding documents and examples'; \
echo ' dt_binding_schema - Build processed device tree binding schemas'; \
echo ' dtbs_check - Validate device tree source files';\
kbuild: consolidate Devicetree dtb build rules There is nothing arch specific about building dtb files other than their location under /arch/*/boot/dts/. Keeping each arch aligned is a pain. The dependencies and supported targets are all slightly different. Also, a cross-compiler for each arch is needed, but really the host compiler preprocessor is perfectly fine for building dtbs. Move the build rules to a common location and remove the arch specific ones. This is done in a single step to avoid warnings about overriding rules. The build dependencies had been a mixture of 'scripts' and/or 'prepare'. These pull in several dependencies some of which need a target compiler (specifically devicetable-offsets.h) and aren't needed to build dtbs. All that is really needed is dtc, so adjust the dependencies to only be dtc. This change enables support 'dtbs_install' on some arches which were missing the target. Acked-by: Will Deacon <will.deacon@arm.com> Acked-by: Paul Burton <paul.burton@mips.com> Acked-by: Ley Foon Tan <ley.foon.tan@intel.com> Acked-by: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Michal Marek <michal.lkml@markovi.net> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Russell King <linux@armlinux.org.uk> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: James Hogan <jhogan@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Zankel <chris@zankel.net> Cc: Max Filippov <jcmvbkbc@gmail.com> Cc: linux-kbuild@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Cc: linux-arm-kernel@lists.infradead.org Cc: uclinux-h8-devel@lists.sourceforge.jp Cc: linux-mips@linux-mips.org Cc: nios2-dev@lists.rocketboards.org Cc: linuxppc-dev@lists.ozlabs.org Cc: linux-xtensa@linux-xtensa.org Signed-off-by: Rob Herring <robh@kernel.org>
2018-01-10 21:19:37 +00:00
echo '')
@echo 'Userspace tools targets:'
@echo ' use "make tools/help"'
@echo ' or "cd tools; make help"'
@echo ''
@echo 'Kernel packaging:'
@$(MAKE) -f $(srctree)/scripts/Makefile.package help
@echo ''
@echo 'Documentation targets:'
@$(MAKE) -f $(srctree)/Documentation/Makefile dochelp
@echo ''
@echo 'Architecture-specific targets ($(SRCARCH)):'
@$(or $(archhelp),\
echo ' No architecture-specific help defined for $(SRCARCH)')
@echo ''
@$(if $(boards), \
$(foreach b, $(boards), \
printf " %-27s - Build for %s\\n" $(b) $(subst _defconfig,,$(b));) \
echo '')
@$(if $(board-dirs), \
$(foreach b, $(board-dirs), \
printf " %-16s - Show %s-specific targets\\n" help-$(b) $(b);) \
printf " %-16s - Show all of the above\\n" help-boards; \
echo '')
@echo ' make V=n [targets] 1: verbose build'
@echo ' 2: give reason for rebuild of target'
@echo ' V=1 and V=2 can be combined with V=12'
@echo ' make O=dir [targets] Locate all output files in "dir", including .config'
@echo ' make C=1 [targets] Check re-compiled c source with $$CHECK'
@echo ' (sparse by default)'
@echo ' make C=2 [targets] Force check of all c source with $$CHECK'
@echo ' make RECORDMCOUNT_WARN=1 [targets] Warn about ignored mcount sections'
@echo ' make W=n [targets] Enable extra build checks, n=1,2,3,c,e where'
@echo ' 1: warnings which may be relevant and do not occur too often'
@echo ' 2: warnings which occur quite often but may still be relevant'
@echo ' 3: more obscure warnings, can most likely be ignored'
@echo ' c: extra checks in the configuration stage (Kconfig)'
@echo ' e: warnings are being treated as errors'
@echo ' Multiple levels can be combined with W=12 or W=123'
@$(if $(dtstree), \
echo ' make CHECK_DTBS=1 [targets] Check all generated dtb files against schema'; \
echo ' This can be applied both to "dtbs" and to individual "foo.dtb" targets' ; \
)
@echo ''
@echo 'Execute "make" or "make all" to build all targets marked with [*] '
@echo 'For further info see the ./README file'
help-board-dirs := $(addprefix help-,$(board-dirs))
help-boards: $(help-board-dirs)
boards-per-dir = $(sort $(notdir $(wildcard $(srctree)/arch/$(SRCARCH)/configs/$*/*_defconfig)))
$(help-board-dirs): help-%:
@echo 'Architecture-specific targets ($(SRCARCH) $*):'
@$(if $(boards-per-dir), \
$(foreach b, $(boards-per-dir), \
printf " %-24s - Build for %s\\n" $*/$(b) $(subst _defconfig,,$(b));) \
echo '')
# Documentation targets
# ---------------------------------------------------------------------------
DOC_TARGETS := xmldocs latexdocs pdfdocs htmldocs epubdocs cleandocs \
linkcheckdocs dochelp refcheckdocs texinfodocs infodocs
Documentation/sphinx: add basic working Sphinx configuration and build Add basic configuration and makefile to build documentation from any .rst files under Documentation using Sphinx. For starters, there's just the placeholder index.rst. At the top level Makefile, hook Sphinx documentation targets alongside (but independent of) the DocBook toolchain, having both be run on the various 'make *docs' targets. All Sphinx processing is placed into Documentation/Makefile.sphinx. Both that and the Documentation/DocBook/Makefile are now expected to handle all the documentation targets, explicitly ignoring them if they're not relevant for that particular toolchain. The changes to the existing DocBook Makefile are kept minimal. There is graceful handling of missing Sphinx and rst2pdf (which is needed for pdf output) by checking for the tool and python module, respectively, with informative messages to the user. If the Read the Docs theme (sphinx_rtd_theme) is available, use it, but otherwise gracefully fall back to the Sphinx default theme, with an informative message to the user, and slightly less pretty HTML output. Sphinx can now handle htmldocs, pdfdocs (if rst2pdf is available), epubdocs and xmldocs targets. The output documents are written into per output type subdirectories under Documentation/output. Finally, you can pass options to sphinx-build using the SPHINXBUILD make variable. For example, 'make SPHINXOPTS=-v htmldocs' for more verbose output from Sphinx. This is based on the original work by Jonathan Corbet, but he probably wouldn't recognize this as his own anymore. Signed-off-by: Jani Nikula <jani.nikula@intel.com>
2016-05-19 12:14:05 +00:00
PHONY += $(DOC_TARGETS)
$(DOC_TARGETS):
$(Q)$(MAKE) $(build)=Documentation $@
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# Rust targets
# ---------------------------------------------------------------------------
# "Is Rust available?" target
PHONY += rustavailable
rustavailable:
kbuild: mark `rustc` (and others) invocations as recursive `rustc` (like Cargo) may take advantage of the jobserver at any time (e.g. for backend parallelism, or eventually frontend too). In the kernel, we call `rustc` with `-Ccodegen-units=1` (and `-Zthreads` is 1 so far), so we do not expect parallelism. However, in the upcoming Rust 1.76.0, a warning is emitted by `rustc` [1] when it cannot connect to the jobserver it was passed (in many cases, but not all: compiling and `--print sysroot` do, but `--version` does not). And given GNU Make always passes the jobserver in the environment variable (even when a line is deemed non-recursive), `rustc` will end up complaining about it (in particular in Make 4.3 where there is only the simple pipe jobserver style). One solution is to remove the jobserver from `MAKEFLAGS`. However, we can mark the lines with calls to `rustc` (and Cargo) as recursive, which looks simpler. This is being documented as a recommendation in `rustc` [2] and allows us to be ready for the time we may use parallelism inside `rustc` (potentially now, if a user passes `-Zthreads`). Thus do so. Similarly, do the same for `rustdoc` and `cargo` calls. Finally, there is one case that the solution does not cover, which is the `$(shell ...)` call we have. Thus, for that one, set an empty `MAKEFLAGS` environment variable. Link: https://github.com/rust-lang/rust/issues/120515 [1] Acked-by: Masahiro Yamada <masahiroy@kernel.org> Link: https://github.com/rust-lang/rust/pull/121564 [2] Link: https://lore.kernel.org/r/20240217002638.57373-1-ojeda@kernel.org [ Reworded to add link to PR documenting the recommendation. ] Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2024-02-17 00:26:37 +00:00
+$(Q)$(CONFIG_SHELL) $(srctree)/scripts/rust_is_available.sh && echo "Rust is available!"
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
# Documentation target
#
# Using the singular to avoid running afoul of `no-dot-config-targets`.
PHONY += rustdoc
rustdoc: prepare
$(Q)$(MAKE) $(build)=rust $@
# Testing target
PHONY += rusttest
rusttest: prepare
$(Q)$(MAKE) $(build)=rust $@
# Formatting targets
PHONY += rustfmt rustfmtcheck
# We skip `rust/alloc` since we want to minimize the diff w.r.t. upstream.
#
# We match using absolute paths since `find` does not resolve them
# when matching, which is a problem when e.g. `srctree` is `..`.
# We `grep` afterwards in order to remove the directory entry itself.
rustfmt:
$(Q)find $(abs_srctree) -type f -name '*.rs' \
-o -path $(abs_srctree)/rust/alloc -prune \
-o -path $(abs_objtree)/rust/test -prune \
| grep -Fv $(abs_srctree)/rust/alloc \
| grep -Fv $(abs_objtree)/rust/test \
| grep -Fv generated \
| xargs $(RUSTFMT) $(rustfmt_flags)
rustfmtcheck: rustfmt_flags = --check
rustfmtcheck: rustfmt
# Misc
# ---------------------------------------------------------------------------
kbuild: make W=1 warn files that are tracked but ignored by git The top .gitignore comments about how to detect files breaking .gitignore rules, but people rarely care about it. Add a new W=1 warning to detect files that are tracked but ignored by git. If git is not installed or the source tree is not tracked by git at all, this script does not print anything. Running it on v6.2-rc1 detected the following: $ make W=1 misc-check Documentation/devicetree/bindings/.yamllint: warning: ignored by one of the .gitignore files drivers/clk/.kunitconfig: warning: ignored by one of the .gitignore files drivers/gpu/drm/tests/.kunitconfig: warning: ignored by one of the .gitignore files drivers/hid/.kunitconfig: warning: ignored by one of the .gitignore files fs/ext4/.kunitconfig: warning: ignored by one of the .gitignore files fs/fat/.kunitconfig: warning: ignored by one of the .gitignore files kernel/kcsan/.kunitconfig: warning: ignored by one of the .gitignore files lib/kunit/.kunitconfig: warning: ignored by one of the .gitignore files mm/kfence/.kunitconfig: warning: ignored by one of the .gitignore files tools/testing/selftests/arm64/tags/.gitignore: warning: ignored by one of the .gitignore files tools/testing/selftests/arm64/tags/Makefile: warning: ignored by one of the .gitignore files tools/testing/selftests/arm64/tags/run_tags_test.sh: warning: ignored by one of the .gitignore files tools/testing/selftests/arm64/tags/tags_test.c: warning: ignored by one of the .gitignore files These are ignored by the '.*' or 'tags' in the top .gitignore, but there is no rule to negate it. You might be tempted to do 'git add -f' but I want to have the real issue fixed (by fixing a .gitignore, or by renaming files, etc.). Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2022-12-29 07:43:10 +00:00
PHONY += misc-check
misc-check:
$(Q)$(srctree)/scripts/misc-check
all: misc-check
PHONY += scripts_gdb
scripts_gdb: prepare0
$(Q)$(MAKE) $(build)=scripts/gdb
$(Q)ln -fsn $(abspath $(srctree)/scripts/gdb/vmlinux-gdb.py)
ifdef CONFIG_GDB_SCRIPTS
all: scripts_gdb
endif
else # KBUILD_EXTMOD
filechk_kernel.release = echo $(KERNELRELEASE)
###
# External module support.
# When building external modules the kernel used as basis is considered
# read-only, and no consistency checks are made and the make
# system is not used on the basis kernel. If updates are required
# in the basis kernel ordinary make commands (without M=...) must be used.
# We are always building only modules.
KBUILD_BUILTIN :=
KBUILD_MODULES := 1
build-dir := $(KBUILD_EXTMOD)
kbuild: wire up the build rule of compile_commands.json to Makefile Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-22 14:56:16 +00:00
compile_commands.json: $(extmod_prefix)compile_commands.json
kbuild: wire up the build rule of compile_commands.json to Makefile Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-22 14:56:16 +00:00
PHONY += compile_commands.json
clean-dirs := $(KBUILD_EXTMOD)
kbuild: add 'private' to target-specific variables Currently, Kbuild produces inconsistent results in some cases. You can do an interesting experiment using the --shuffle option, which is supported by GNU Make 4.4 or later. Set CONFIG_KVM_INTEL=y and CONFIG_KVM_AMD=m (or vice versa), and repeat incremental builds w/wo --shuffle=reverse. $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s $ make --shuffle=reverse [ snip ] CC [M] arch/x86/kvm/kvm-asm-offsets.s $ make [ snip ] CC arch/x86/kvm/kvm-asm-offsets.s arch/x86/kvm/kvm-asm-offsets.s is rebuilt every time w/wo the [M] marker. arch/x86/kvm/kvm-asm-offsets.s is built as built-in when it is built as a prerequisite of arch/x86/kvm/kvm-intel.o, which is built-in. arch/x86/kvm/kvm-asm-offsets.s is built as modular when it is built as a prerequisite of arch/x86/kvm/kvm-amd.o, which is a module. Another odd example is single target builds. When CONFIG_LKDTM=m, drivers/misc/lkdtm/rodata.o can be built as built-in or modular, depending on how it is built. $ make drivers/misc/lkdtm/lkdtm.o [ snip ] CC [M] drivers/misc/lkdtm/rodata.o $ make drivers/misc/lkdtm/rodata.o [ snip ] CC drivers/misc/lkdtm/rodata.o drivers/misc/lkdtm/rodata.o is built as modular when it is built as a prerequisite of another, but built as built-in when it is a final target. The same thing happens to drivers/memory/emif-asm-offsets.s when CONFIG_TI_EMIF_SRAM=m. $ make drivers/memory/ti-emif-sram.o [ snip ] CC [M] drivers/memory/emif-asm-offsets.s $ make drivers/memory/emif-asm-offsets.s [ snip ] CC drivers/memory/emif-asm-offsets.s This is because the part-of-module=y flag defined for the modules is inherited by its prerequisites. Target-specific variables are likely intended only for local use. This commit adds 'private' to them. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <n.schier@avm.de>
2024-04-27 15:32:53 +00:00
clean: private rm-files := $(KBUILD_EXTMOD)/Module.symvers $(KBUILD_EXTMOD)/modules.nsdeps \
kbuild: Remove support for Clang's ThinLTO caching There is an issue in clang's ThinLTO caching (enabled for the kernel via '--thinlto-cache-dir') with .incbin, which the kernel occasionally uses to include data within the kernel, such as the .config file for /proc/config.gz. For example, when changing the .config and rebuilding vmlinux, the copy of .config in vmlinux does not match the copy of .config in the build folder: $ echo 'CONFIG_LTO_NONE=n CONFIG_LTO_CLANG_THIN=y CONFIG_IKCONFIG=y CONFIG_HEADERS_INSTALL=y' >kernel/configs/repro.config $ make -skj"$(nproc)" ARCH=x86_64 LLVM=1 clean defconfig repro.config vmlinux ... $ grep CONFIG_HEADERS_INSTALL .config CONFIG_HEADERS_INSTALL=y $ scripts/extract-ikconfig vmlinux | grep CONFIG_HEADERS_INSTALL CONFIG_HEADERS_INSTALL=y $ scripts/config -d HEADERS_INSTALL $ make -kj"$(nproc)" ARCH=x86_64 LLVM=1 vmlinux ... UPD kernel/config_data GZIP kernel/config_data.gz CC kernel/configs.o ... LD vmlinux ... $ grep CONFIG_HEADERS_INSTALL .config # CONFIG_HEADERS_INSTALL is not set $ scripts/extract-ikconfig vmlinux | grep CONFIG_HEADERS_INSTALL CONFIG_HEADERS_INSTALL=y Without '--thinlto-cache-dir' or when using full LTO, this issue does not occur. Benchmarking incremental builds on a few different machines with and without the cache shows a 20% increase in incremental build time without the cache when measured by touching init/main.c and running 'make all'. ARCH=arm64 defconfig + CONFIG_LTO_CLANG_THIN=y on an arm64 host: Benchmark 1: With ThinLTO cache Time (mean ± σ): 56.347 s ± 0.163 s [User: 83.768 s, System: 24.661 s] Range (min … max): 56.109 s … 56.594 s 10 runs Benchmark 2: Without ThinLTO cache Time (mean ± σ): 67.740 s ± 0.479 s [User: 718.458 s, System: 31.797 s] Range (min … max): 67.059 s … 68.556 s 10 runs Summary With ThinLTO cache ran 1.20 ± 0.01 times faster than Without ThinLTO cache ARCH=x86_64 defconfig + CONFIG_LTO_CLANG_THIN=y on an x86_64 host: Benchmark 1: With ThinLTO cache Time (mean ± σ): 85.772 s ± 0.252 s [User: 91.505 s, System: 8.408 s] Range (min … max): 85.447 s … 86.244 s 10 runs Benchmark 2: Without ThinLTO cache Time (mean ± σ): 103.833 s ± 0.288 s [User: 232.058 s, System: 8.569 s] Range (min … max): 103.286 s … 104.124 s 10 runs Summary With ThinLTO cache ran 1.21 ± 0.00 times faster than Without ThinLTO cache While it is unfortunate to take this performance improvement off the table, correctness is more important. If/when this is fixed in LLVM, it can potentially be brought back in a conditional manner. Alternatively, a developer can just disable LTO if doing incremental compiles quickly is important, as a full compile cycle can still take over a minute even with the cache and it is unlikely that LTO will result in functional differences for a kernel change. Cc: stable@vger.kernel.org Fixes: dc5723b02e52 ("kbuild: add support for Clang LTO") Reported-by: Yifan Hong <elsk@google.com> Closes: https://github.com/ClangBuiltLinux/linux/issues/2021 Reported-by: Masami Hiramatsu <mhiramat@kernel.org> Closes: https://lore.kernel.org/r/20220327115526.cc4b0ff55fc53c97683c3e4d@kernel.org/ Signed-off-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2024-05-01 22:55:25 +00:00
$(KBUILD_EXTMOD)/compile_commands.json
kbuild: warn if a different compiler is used for external module builds It is always safe to use the same compiler for the kernel and external modules, but in reality, some distributions such as Fedora release a different version of GCC from the one used for building the kernel. There was a long discussion about mixing different compilers [1]. I do not repeat it here, but at least, showing a heads up in that case is better than nothing. Linus suggested [2]: And a warning might be more palatable even if different compiler version work fine together. Just a heads up on "it looks like you might be mixing compiler versions" is a valid note, and isn't necessarily wrong. Even when they work well together, maybe you want to have people at least _aware_ of it. This commit shows a warning unless the compiler is exactly the same. warning: the compiler differs from the one used to build the kernel The kernel was built by: gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3) You are using: gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1) Check the difference, and if it is OK with you, please proceed at your risk. To avoid the locale issue as in commit bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale"), pass LC_ALL=C to "$(CC) --version". [1] https://lore.kernel.org/linux-hardening/efe6b039a544da8215d5e54aa7c4b6d1986fc2b0.1611607264.git.jpoimboe@redhat.com/ [2] https://lore.kernel.org/lkml/CAHk-=wgjwhDy-y4mQh34L+2aF=n6BjzHdqAW2=8wri5x7O04pA@mail.gmail.com/ Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-01 02:53:46 +00:00
PHONY += prepare
# now expand this into a simple variable to reduce the cost of shell evaluations
prepare: CC_VERSION_TEXT := $(CC_VERSION_TEXT)
prepare:
kbuild: do not quote string values in include/config/auto.conf The previous commit fixed up all shell scripts to not include include/config/auto.conf. Now that include/config/auto.conf is only included by Makefiles, we can change it into a more Make-friendly form. Previously, Kconfig output string values enclosed with double-quotes (both in the .config and include/config/auto.conf): CONFIG_X="foo bar" Unlike shell, Make handles double-quotes (and single-quotes as well) verbatim. We must rip them off when used. There are some patterns: [1] $(patsubst "%",%,$(CONFIG_X)) [2] $(CONFIG_X:"%"=%) [3] $(subst ",,$(CONFIG_X)) [4] $(shell echo $(CONFIG_X)) These are not only ugly, but also fragile. [1] and [2] do not work if the value contains spaces, like CONFIG_X=" foo bar " [3] does not work correctly if the value contains double-quotes like CONFIG_X="foo\"bar" [4] seems to work better, but has a cost of forking a process. Anyway, quoted strings were always PITA for our Makefiles. This commit changes Kconfig to stop quoting in include/config/auto.conf. These are the string type symbols referenced in Makefiles or scripts: ACPI_CUSTOM_DSDT_FILE ARC_BUILTIN_DTB_NAME ARC_TUNE_MCPU BUILTIN_DTB_SOURCE CC_IMPLICIT_FALLTHROUGH CC_VERSION_TEXT CFG80211_EXTRA_REGDB_KEYDIR EXTRA_FIRMWARE EXTRA_FIRMWARE_DIR EXTRA_TARGETS H8300_BUILTIN_DTB INITRAMFS_SOURCE LOCALVERSION MODULE_SIG_HASH MODULE_SIG_KEY NDS32_BUILTIN_DTB NIOS2_DTB_SOURCE OPENRISC_BUILTIN_DTB SOC_CANAAN_K210_DTB_SOURCE SYSTEM_BLACKLIST_HASH_LIST SYSTEM_REVOCATION_KEYS SYSTEM_TRUSTED_KEYS TARGET_CPU UNUSED_KSYMS_WHITELIST XILINX_MICROBLAZE0_FAMILY XILINX_MICROBLAZE0_HW_VER XTENSA_VARIANT_NAME I checked them one by one, and fixed up the code where necessary. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-12-14 02:53:53 +00:00
@if [ "$(CC_VERSION_TEXT)" != "$(CONFIG_CC_VERSION_TEXT)" ]; then \
kbuild: warn if a different compiler is used for external module builds It is always safe to use the same compiler for the kernel and external modules, but in reality, some distributions such as Fedora release a different version of GCC from the one used for building the kernel. There was a long discussion about mixing different compilers [1]. I do not repeat it here, but at least, showing a heads up in that case is better than nothing. Linus suggested [2]: And a warning might be more palatable even if different compiler version work fine together. Just a heads up on "it looks like you might be mixing compiler versions" is a valid note, and isn't necessarily wrong. Even when they work well together, maybe you want to have people at least _aware_ of it. This commit shows a warning unless the compiler is exactly the same. warning: the compiler differs from the one used to build the kernel The kernel was built by: gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3) You are using: gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1) Check the difference, and if it is OK with you, please proceed at your risk. To avoid the locale issue as in commit bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale"), pass LC_ALL=C to "$(CC) --version". [1] https://lore.kernel.org/linux-hardening/efe6b039a544da8215d5e54aa7c4b6d1986fc2b0.1611607264.git.jpoimboe@redhat.com/ [2] https://lore.kernel.org/lkml/CAHk-=wgjwhDy-y4mQh34L+2aF=n6BjzHdqAW2=8wri5x7O04pA@mail.gmail.com/ Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-01 02:53:46 +00:00
echo >&2 "warning: the compiler differs from the one used to build the kernel"; \
kbuild: do not quote string values in include/config/auto.conf The previous commit fixed up all shell scripts to not include include/config/auto.conf. Now that include/config/auto.conf is only included by Makefiles, we can change it into a more Make-friendly form. Previously, Kconfig output string values enclosed with double-quotes (both in the .config and include/config/auto.conf): CONFIG_X="foo bar" Unlike shell, Make handles double-quotes (and single-quotes as well) verbatim. We must rip them off when used. There are some patterns: [1] $(patsubst "%",%,$(CONFIG_X)) [2] $(CONFIG_X:"%"=%) [3] $(subst ",,$(CONFIG_X)) [4] $(shell echo $(CONFIG_X)) These are not only ugly, but also fragile. [1] and [2] do not work if the value contains spaces, like CONFIG_X=" foo bar " [3] does not work correctly if the value contains double-quotes like CONFIG_X="foo\"bar" [4] seems to work better, but has a cost of forking a process. Anyway, quoted strings were always PITA for our Makefiles. This commit changes Kconfig to stop quoting in include/config/auto.conf. These are the string type symbols referenced in Makefiles or scripts: ACPI_CUSTOM_DSDT_FILE ARC_BUILTIN_DTB_NAME ARC_TUNE_MCPU BUILTIN_DTB_SOURCE CC_IMPLICIT_FALLTHROUGH CC_VERSION_TEXT CFG80211_EXTRA_REGDB_KEYDIR EXTRA_FIRMWARE EXTRA_FIRMWARE_DIR EXTRA_TARGETS H8300_BUILTIN_DTB INITRAMFS_SOURCE LOCALVERSION MODULE_SIG_HASH MODULE_SIG_KEY NDS32_BUILTIN_DTB NIOS2_DTB_SOURCE OPENRISC_BUILTIN_DTB SOC_CANAAN_K210_DTB_SOURCE SYSTEM_BLACKLIST_HASH_LIST SYSTEM_REVOCATION_KEYS SYSTEM_TRUSTED_KEYS TARGET_CPU UNUSED_KSYMS_WHITELIST XILINX_MICROBLAZE0_FAMILY XILINX_MICROBLAZE0_HW_VER XTENSA_VARIANT_NAME I checked them one by one, and fixed up the code where necessary. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-12-14 02:53:53 +00:00
echo >&2 " The kernel was built by: $(CONFIG_CC_VERSION_TEXT)"; \
kbuild: warn if a different compiler is used for external module builds It is always safe to use the same compiler for the kernel and external modules, but in reality, some distributions such as Fedora release a different version of GCC from the one used for building the kernel. There was a long discussion about mixing different compilers [1]. I do not repeat it here, but at least, showing a heads up in that case is better than nothing. Linus suggested [2]: And a warning might be more palatable even if different compiler version work fine together. Just a heads up on "it looks like you might be mixing compiler versions" is a valid note, and isn't necessarily wrong. Even when they work well together, maybe you want to have people at least _aware_ of it. This commit shows a warning unless the compiler is exactly the same. warning: the compiler differs from the one used to build the kernel The kernel was built by: gcc (GCC) 11.1.1 20210531 (Red Hat 11.1.1-3) You are using: gcc (GCC) 11.2.1 20210728 (Red Hat 11.2.1-1) Check the difference, and if it is OK with you, please proceed at your risk. To avoid the locale issue as in commit bcbcf50f5218 ("kbuild: fix ld-version.sh to not be affected by locale"), pass LC_ALL=C to "$(CC) --version". [1] https://lore.kernel.org/linux-hardening/efe6b039a544da8215d5e54aa7c4b6d1986fc2b0.1611607264.git.jpoimboe@redhat.com/ [2] https://lore.kernel.org/lkml/CAHk-=wgjwhDy-y4mQh34L+2aF=n6BjzHdqAW2=8wri5x7O04pA@mail.gmail.com/ Acked-by: Josh Poimboeuf <jpoimboe@redhat.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2021-08-01 02:53:46 +00:00
echo >&2 " You are using: $(CC_VERSION_TEXT)"; \
fi
PHONY += help
help:
@echo ' Building external modules.'
@echo ' Syntax: make -C path/to/kernel/src M=$$PWD target'
@echo ''
@echo ' modules - default target, build the module(s)'
@echo ' modules_install - install the module'
@echo ' clean - remove generated files in module directory only'
@echo ' rust-analyzer - generate rust-project.json rust-analyzer support file'
@echo ''
ifndef CONFIG_MODULES
modules modules_install: __external_modules_error
__external_modules_error:
@echo >&2 '***'
@echo >&2 '*** The present kernel disabled CONFIG_MODULES.'
@echo >&2 '*** You cannot build or install external modules.'
@echo >&2 '***'
@false
endif
endif # KBUILD_EXTMOD
# ---------------------------------------------------------------------------
# Modules
PHONY += modules modules_install modules_sign modules_prepare
modules_install:
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modinst \
sign-only=$(if $(filter modules_install,$(MAKECMDGOALS)),,y)
ifeq ($(CONFIG_MODULE_SIG),y)
# modules_sign is a subset of modules_install.
# 'make modules_install modules_sign' is equivalent to 'make modules_install'.
modules_sign: modules_install
@:
else
modules_sign:
@echo >&2 '***'
@echo >&2 '*** CONFIG_MODULE_SIG is disabled. You cannot sign modules.'
@echo >&2 '***'
@false
endif
ifdef CONFIG_MODULES
$(MODORDER): $(build-dir)
@:
# KBUILD_MODPOST_NOFINAL can be set to skip the final link of modules.
# This is solely useful to speed up test compiles.
modules: modpost
ifneq ($(KBUILD_MODPOST_NOFINAL),1)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
endif
PHONY += modules_check
modules_check: $(MODORDER)
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/modules-check.sh $<
else # CONFIG_MODULES
modules:
@:
KBUILD_MODULES :=
endif # CONFIG_MODULES
PHONY += modpost
modpost: $(if $(single-build),, $(if $(KBUILD_BUILTIN), vmlinux.o)) \
$(if $(KBUILD_MODULES), modules_check)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
# Single targets
# ---------------------------------------------------------------------------
# To build individual files in subdirectories, you can do like this:
#
# make foo/bar/baz.s
#
# The supported suffixes for single-target are listed in 'single-targets'
#
# To build only under specific subdirectories, you can do like this:
#
# make foo/bar/baz/
ifdef single-build
# .ko is special because modpost is needed
single-ko := $(sort $(filter %.ko, $(MAKECMDGOALS)))
single-no-ko := $(filter-out $(single-ko), $(MAKECMDGOALS)) \
$(foreach x, o mod, $(patsubst %.ko, %.$x, $(single-ko)))
$(single-ko): single_modules
@:
$(single-no-ko): $(build-dir)
@:
# Remove MODORDER when done because it is not the real one.
PHONY += single_modules
single_modules: $(single-no-ko) modules_prepare
$(Q){ $(foreach m, $(single-ko), echo $(extmod_prefix)$(m:%.ko=%.o);) } > $(MODORDER)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modpost
ifneq ($(KBUILD_MODPOST_NOFINAL),1)
$(Q)$(MAKE) -f $(srctree)/scripts/Makefile.modfinal
endif
$(Q)rm -f $(MODORDER)
single-goals := $(addprefix $(build-dir)/, $(single-no-ko))
KBUILD_MODULES := 1
endif
# Preset locale variables to speed up the build process. Limit locale
# tweaks to this spot to avoid wrong language settings when running
# make menuconfig etc.
# Error messages still appears in the original language
PHONY += $(build-dir)
$(build-dir): prepare
$(Q)$(MAKE) $(build)=$@ need-builtin=1 need-modorder=1 $(single-goals)
clean-dirs := $(addprefix _clean_, $(clean-dirs))
PHONY += $(clean-dirs) clean
$(clean-dirs):
$(Q)$(MAKE) $(clean)=$(patsubst _clean_%,%,$@)
clean: $(clean-dirs)
$(call cmd,rmfiles)
@find $(or $(KBUILD_EXTMOD), .) $(RCS_FIND_IGNORE) \
Kbuild: add Rust support Having most of the new files in place, we now enable Rust support in the build system, including `Kconfig` entries related to Rust, the Rust configuration printer and a few other bits. Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Co-developed-by: Alex Gaynor <alex.gaynor@gmail.com> Signed-off-by: Alex Gaynor <alex.gaynor@gmail.com> Co-developed-by: Finn Behrens <me@kloenk.de> Signed-off-by: Finn Behrens <me@kloenk.de> Co-developed-by: Adam Bratschi-Kaye <ark.email@gmail.com> Signed-off-by: Adam Bratschi-Kaye <ark.email@gmail.com> Co-developed-by: Wedson Almeida Filho <wedsonaf@google.com> Signed-off-by: Wedson Almeida Filho <wedsonaf@google.com> Co-developed-by: Michael Ellerman <mpe@ellerman.id.au> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Co-developed-by: Sven Van Asbroeck <thesven73@gmail.com> Signed-off-by: Sven Van Asbroeck <thesven73@gmail.com> Co-developed-by: Gary Guo <gary@garyguo.net> Signed-off-by: Gary Guo <gary@garyguo.net> Co-developed-by: Boris-Chengbiao Zhou <bobo1239@web.de> Signed-off-by: Boris-Chengbiao Zhou <bobo1239@web.de> Co-developed-by: Boqun Feng <boqun.feng@gmail.com> Signed-off-by: Boqun Feng <boqun.feng@gmail.com> Co-developed-by: Douglas Su <d0u9.su@outlook.com> Signed-off-by: Douglas Su <d0u9.su@outlook.com> Co-developed-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Signed-off-by: Dariusz Sosnowski <dsosnowski@dsosnowski.pl> Co-developed-by: Antonio Terceiro <antonio.terceiro@linaro.org> Signed-off-by: Antonio Terceiro <antonio.terceiro@linaro.org> Co-developed-by: Daniel Xu <dxu@dxuuu.xyz> Signed-off-by: Daniel Xu <dxu@dxuuu.xyz> Co-developed-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Signed-off-by: Björn Roy Baron <bjorn3_gh@protonmail.com> Co-developed-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Martin Rodriguez Reboredo <yakoyoku@gmail.com> Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
2021-07-03 14:42:57 +00:00
\( -name '*.[aios]' -o -name '*.rsi' -o -name '*.ko' -o -name '.*.cmd' \
-o -name '*.ko.*' \
-o -name '*.dtb' -o -name '*.dtbo' \
-o -name '*.dtb.S' -o -name '*.dtbo.S' \
-o -name '*.dt.yaml' -o -name 'dtbs-list' \
-o -name '*.dwo' -o -name '*.lst' \
kbuild: implement CONFIG_TRIM_UNUSED_KSYMS without recursion When CONFIG_TRIM_UNUSED_KSYMS is enabled, Kbuild recursively traverses the directory tree to determine which EXPORT_SYMBOL to trim. If an EXPORT_SYMBOL turns out to be unused by anyone, Kbuild begins the second traverse, where some source files are recompiled with their EXPORT_SYMBOL() tuned into a no-op. Linus stated negative opinions about this slowness in commits: - 5cf0fd591f2e ("Kbuild: disable TRIM_UNUSED_KSYMS option") - a555bdd0c58c ("Kbuild: enable TRIM_UNUSED_KSYMS again, with some guarding") We can do this better now. The final data structures of EXPORT_SYMBOL are generated by the modpost stage, so modpost can selectively emit KSYMTAB entries that are really used by modules. Commit f73edc8951b2 ("kbuild: unify two modpost invocations") is another ground-work to do this in a one-pass algorithm. With the list of modules, modpost sets sym->used if it is used by a module. modpost emits KSYMTAB only for symbols with sym->used==true. BTW, Nicolas explained why the trimming was implemented with recursion: https://lore.kernel.org/all/2o2rpn97-79nq-p7s2-nq5-8p83391473r@syhkavp.arg/ Actually, we never achieved that level of optimization where the chain reaction of trimming comes into play because: - CONFIG_LTO_CLANG cannot remove any unused symbols - CONFIG_LD_DEAD_CODE_DATA_ELIMINATION is enabled only for vmlinux, but not modules If deeper trimming is required, we need to revisit this, but I guess that is unlikely to happen. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2023-06-11 15:50:57 +00:00
-o -name '*.su' -o -name '*.mod' \
-o -name '.*.d' -o -name '.*.tmp' -o -name '*.mod.c' \
-o -name '*.lex.c' -o -name '*.tab.[ch]' \
-o -name '*.asn1.[ch]' \
-o -name '*.symtypes' -o -name 'modules.order' \
GCC plugin infrastructure This patch allows to build the whole kernel with GCC plugins. It was ported from grsecurity/PaX. The infrastructure supports building out-of-tree modules and building in a separate directory. Cross-compilation is supported too. Currently the x86, arm, arm64 and uml architectures enable plugins. The directory of the gcc plugins is scripts/gcc-plugins. You can use a file or a directory there. The plugins compile with these options: * -fno-rtti: gcc is compiled with this option so the plugins must use it too * -fno-exceptions: this is inherited from gcc too * -fasynchronous-unwind-tables: this is inherited from gcc too * -ggdb: it is useful for debugging a plugin (better backtrace on internal errors) * -Wno-narrowing: to suppress warnings from gcc headers (ipa-utils.h) * -Wno-unused-variable: to suppress warnings from gcc headers (gcc_version variable, plugin-version.h) The infrastructure introduces a new Makefile target called gcc-plugins. It supports all gcc versions from 4.5 to 6.0. The scripts/gcc-plugin.sh script chooses the proper host compiler (gcc-4.7 can be built by either gcc or g++). This script also checks the availability of the included headers in scripts/gcc-plugins/gcc-common.h. The gcc-common.h header contains frequently included headers for GCC plugins and it has a compatibility layer for the supported gcc versions. The gcc-generate-*-pass.h headers automatically generate the registration structures for GIMPLE, SIMPLE_IPA, IPA and RTL passes. Note that 'make clean' keeps the *.so files (only the distclean or mrproper targets clean all) because they are needed for out-of-tree modules. Based on work created by the PaX Team. Signed-off-by: Emese Revfy <re.emese@gmail.com> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Michal Marek <mmarek@suse.com>
2016-05-23 22:09:38 +00:00
-o -name '*.c.[012]*.*' \
-o -name '*.ll' \
-o -name '*.gcno' \
-o -name '*.*.symversions' \) -type f -print \
-o -name '.tmp_*' -print \
| xargs rm -rf
# Generate tags for editors
# ---------------------------------------------------------------------------
quiet_cmd_tags = GEN $@
cmd_tags = $(BASH) $(srctree)/scripts/tags.sh $@
tags TAGS cscope gtags: FORCE
$(call cmd,tags)
# IDE support targets
PHONY += rust-analyzer
rust-analyzer:
$(Q)$(MAKE) $(build)=rust $@
# Script to generate missing namespace dependencies
# ---------------------------------------------------------------------------
PHONY += nsdeps
nsdeps: export KBUILD_NSDEPS=1
nsdeps: modules
$(Q)$(CONFIG_SHELL) $(srctree)/scripts/nsdeps
kbuild: wire up the build rule of compile_commands.json to Makefile Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-22 14:56:16 +00:00
# Clang Tooling
# ---------------------------------------------------------------------------
quiet_cmd_gen_compile_commands = GEN $@
cmd_gen_compile_commands = $(PYTHON3) $< -a $(AR) -o $@ $(filter-out $<, $(real-prereqs))
$(extmod_prefix)compile_commands.json: scripts/clang-tools/gen_compile_commands.py \
$(if $(KBUILD_EXTMOD),, vmlinux.a $(KBUILD_VMLINUX_LIBS)) \
kbuild: wire up the build rule of compile_commands.json to Makefile Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-22 14:56:16 +00:00
$(if $(CONFIG_MODULES), $(MODORDER)) FORCE
$(call if_changed,gen_compile_commands)
targets += $(extmod_prefix)compile_commands.json
kbuild: wire up the build rule of compile_commands.json to Makefile Currently, you need to manually run scripts/gen_compile_commands.py to create compile_commands.json. It parses all the .*.cmd files found under the specified directory. If you rebuild the kernel over again without 'make clean', .*.cmd files from older builds will create stale entries in compile_commands.json. This commit wires up the compile_commands.json rule to Makefile, and makes it parse only the .*.cmd files involved in the current build. Pass $(KBUILD_VMLINUX_OBJS), $(KBUILD_VMLINUX_LIBS), and modules.order to the script. The objects or archives linked to vmlinux are listed in $(KBUILD_VMLINUX_OBJS) or $(KBUILD_VMLINUX_LIBS). All the modules are listed in modules.order. You can create compile_commands.json from Make: $ make -j$(nproc) CC=clang compile_commands.json You can also build vmlinux, modules, and compile_commands.json all together in a single command: $ make -j$(nproc) CC=clang all compile_commands.json It works for M= builds as well. In this case, compile_commands.json is created in the top directory of the external module. This is convenient, but it has a drawback; the coverage of the compile_commands.json is reduced because only the objects linked to vmlinux or modules are handled. For example, the following C files are not included in the compile_commands.json: - Decompressor source files (arch/*/boot/) - VDSO source files - C files used to generate intermediates (e.g. kernel/bounds.c) - Standalone host programs I think it is fine for most developers because our main interest is the kernel-space code. If you want to cover all the compiled C files, please build the kernel, then run the script manually as you did before: $ make clean # if you want to remove stale .cmd files [optional] $ make -j$(nproc) CC=clang $ scripts/gen_compile_commands.py Here is a note for out-of-tree builds. 'make compile_commands.json' works with O= option, but please notice compile_commands.json is created in the object tree instead of the source tree. Some people may want to have compile_commands.json in the source tree because Clang Tools searches for it through all parent paths of the first input source file. However, you cannot do this for O= builds. Kbuild should never generate any build artifact in the source tree when O= is given because the source tree might be read-only. Any write attempt to the source tree is monitored and the violation may be reported. See the commit log of 8ef14c2c41d9. So, the only possible way is to create compile_commands.json in the object tree, then specify '-p <build-path>' when you use clang-check, clang-tidy, etc. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Acked-by: Nick Desaulniers <ndesaulniers@google.com>
2020-08-22 14:56:16 +00:00
Makefile: Add clang-tidy and static analyzer support to makefile This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-22 14:56:18 +00:00
PHONY += clang-tidy clang-analyzer
ifdef CONFIG_CC_IS_CLANG
quiet_cmd_clang_tools = CHECK $<
cmd_clang_tools = $(PYTHON3) $(srctree)/scripts/clang-tools/run-clang-tools.py $@ $<
clang-tidy clang-analyzer: $(extmod_prefix)compile_commands.json
Makefile: Add clang-tidy and static analyzer support to makefile This patch adds clang-tidy and the clang static-analyzer as make targets. The goal of this patch is to make static analysis tools usable and extendable by any developer or researcher who is familiar with basic c++. The current static analysis tools require intimate knowledge of the internal workings of the static analysis. Clang-tidy and the clang static analyzers expose an easy to use api and allow users unfamiliar with clang to write new checks with relative ease. ===Clang-tidy=== Clang-tidy is an easily extendable 'linter' that runs on the AST. Clang-tidy checks are easy to write and understand. A check consists of two parts, a matcher and a checker. The matcher is created using a domain specific language that acts on the AST (https://clang.llvm.org/docs/LibASTMatchersReference.html). When AST nodes are found by the matcher a callback is made to the checker. The checker can then execute additional checks and issue warnings. Here is an example clang-tidy check to report functions that have calls to local_irq_disable without calls to local_irq_enable and vice-versa. Functions flagged with __attribute((annotation("ignore_irq_balancing"))) are ignored for analysis. (https://reviews.llvm.org/D65828) ===Clang static analyzer=== The clang static analyzer is a more powerful static analysis tool that uses symbolic execution to find bugs. Currently there is a check that looks for potential security bugs from invalid uses of kmalloc and kfree. There are several more general purpose checks that are useful for the kernel. The clang static analyzer is well documented and designed to be extensible. (https://clang-analyzer.llvm.org/checker_dev_manual.html) (https://github.com/haoNoQ/clang-analyzer-guide/releases/download/v0.1/clang-analyzer-guide-v0.1.pdf) The main draw of the clang tools is how accessible they are. The clang documentation is very nice and these tools are built specifically to be easily extendable by any developer. They provide an accessible method of bug-finding and research to people who are not overly familiar with the kernel codebase. Signed-off-by: Nathan Huckleberry <nhuck@google.com> Reviewed-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Nick Desaulniers <ndesaulniers@google.com> Tested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-08-22 14:56:18 +00:00
$(call cmd,clang_tools)
else
clang-tidy clang-analyzer:
@echo "$@ requires CC=clang" >&2
@false
endif
# Scripts to check various things for consistency
# ---------------------------------------------------------------------------
scripts: remove namespace.pl namespace.pl is intended to help locate symbols which are defined but are not used externally. The goal is to avoid bloat of the namespace in the resulting kernel image. The script relies on object data, and only finds unused symbols for the configuration used to generate that object data. This results in a lot of false positive warnings such as symbols only used by a single architecture, or symbols which are used externally only under certain configurations. Running namespace.pl using allyesconfig, allmodconfig, and x86_64_defconfig yields the following results: * allmodconfig * 11122 unique symbol names with no external reference * 1194 symbols listed as multiply defined * 214 symbols it can't resolve * allyesconfig * 10997 unique symbol names with no external reference * 1194 symbols listed as multiply defined * 214 symbols it can't resolve * x86_64_defconfig * 5757 unique symbol names with no external reference * 528 symbols listed as multiply defined * 154 symbols it can't resolve The script also has no way to easily limit the scope of the checks to a given subset of the kernel, such as only checking for symbols defined within a module or subsystem. Discussion on public mailing lists seems to indicate that many view the tool output as suspect or not very useful (see discussions at [1] and [2] for further context). As described by Masahiro Yamada at [2], namespace.pl provides 3 types of checks: listing multiply defined symbols, resolving external symbols, and warnings about symbols with no reference. The first category of issues is easily caught by the linker as any set of multiply defined symbols should fail to link. The second category of issues is also caught by linking, as undefined symbols would cause issues. Even with modules, these types of issues where a module relies on an external symbol are caught by modpost. The remaining category of issues reported is the list of symbols with no external reference, and is the primary motivation of this script. However, it ought to be clear from the above examples that the output is difficult to sort through. Even allyesconfig has ~10000 entries. The current submit-checklist indicates that patches ought to go through namespacecheck and fix any new issues arising. But that itself presents problems. As described at [1], many cases of reports are due to configuration where a function is used externally by some configuration settings. Prominent maintainers appear to dislike changes modify code such that symbols become static based on CONFIG_* flags ([3], and [4]) One possible solution is to adjust the advice and indicate that we only care about the output of namespacecheck on allyesconfig or allmodconfig builds... However, given the discussion at [2], I suspect that few people are actively using this tool. It doesn't have a maintainer in the MAINTAINERS flie, and it produces so many warnings for unused symbols that it is difficult to use effectively. Thus, I propose we simply remove it. [1] https://lore.kernel.org/netdev/20200708164812.384ae8ea@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com/ [2] https://lore.kernel.org/lkml/20190129204319.15238-1-jacob.e.keller@intel.com/ [3] https://lore.kernel.org/netdev/20190828.154744.2058157956381129672.davem@davemloft.net/ [4] https://lore.kernel.org/netdev/20190827210928.576c5fef@cakuba.netronome.com/ Signed-off-by: Jacob Keller <jacob.e.keller@intel.com> Acked-by: Randy Dunlap <rdunlap@infradead.org> Acked-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
2020-10-10 00:18:44 +00:00
PHONY += includecheck versioncheck coccicheck export_report
includecheck:
find $(srctree)/* $(RCS_FIND_IGNORE) \
-name '*.[hcS]' -type f -print | sort \
| xargs $(PERL) -w $(srctree)/scripts/checkincludes.pl
versioncheck:
find $(srctree)/* $(RCS_FIND_IGNORE) \
-name '*.[hcS]' -type f -print | sort \
| xargs $(PERL) -w $(srctree)/scripts/checkversion.pl
coccicheck:
$(Q)$(BASH) $(srctree)/scripts/$@
export_report:
$(PERL) $(srctree)/scripts/export_report.pl
PHONY += checkstack kernelrelease kernelversion image_name
# UML needs a little special treatment here. It wants to use the host
# toolchain, so needs $(SUBARCH) passed to checkstack.pl. Everyone
# else wants $(ARCH), including people doing cross-builds, which means
# that $(SUBARCH) doesn't work here.
ifeq ($(ARCH), um)
CHECKSTACK_ARCH := $(SUBARCH)
else
CHECKSTACK_ARCH := $(ARCH)
endif
MINSTACKSIZE ?= 100
checkstack:
$(OBJDUMP) -d vmlinux $$(find . -name '*.ko') | \
$(PERL) $(srctree)/scripts/checkstack.pl $(CHECKSTACK_ARCH) $(MINSTACKSIZE)
kernelrelease:
@$(filechk_kernel.release)
kernelversion:
@echo $(KERNELVERSION)
image_name:
@echo $(KBUILD_IMAGE)
PHONY += run-command
run-command:
$(Q)$(KBUILD_RUN_COMMAND)
quiet_cmd_rmfiles = $(if $(wildcard $(rm-files)),CLEAN $(wildcard $(rm-files)))
cmd_rmfiles = rm -rf $(rm-files)
kbuild: let fixdep directly write to .*.cmd files Currently, fixdep writes dependencies to .*.tmp, which is renamed to .*.cmd after everything succeeds. This is a very safe way to avoid corrupted .*.cmd files. The if_changed_dep has carried this safety mechanism since it was added in 2002. If fixdep fails for some reasons or a user terminates the build while fixdep is running, the incomplete output from the fixdep could be troublesome. This is my insight about some bad scenarios: [1] If the compiler succeeds to generate *.o file, but fixdep fails to write necessary dependencies to .*.cmd file, Make will miss to rebuild the object when headers or CONFIG options are changed. In this case, fixdep should not generate .*.cmd file at all so that 'arg-check' will surely trigger the rebuild of the object. [2] A partially constructed .*.cmd file may not be a syntactically correct makefile. The next time Make runs, it would include it, then fail to parse it. Once this happens, 'make clean' is be the only way to fix it. In fact, [1] is no longer a problem since commit 9c2af1c7377a ("kbuild: add .DELETE_ON_ERROR special target"). Make deletes a target file on any failure in its recipe. Because fixdep is a part of the recipe of *.o target, if it fails, the *.o is deleted anyway. However, I am a bit worried about the slight possibility of [2]. So, here is a solution. Let fixdep directly write to a .*.cmd file, but allow makefiles to include it only when its corresponding target exists. This effectively reverts commit 2982c953570b ("kbuild: remove redundant $(wildcard ...) for cmd_files calculation"), and commit 00d78ab2ba75 ("kbuild: remove dead code in cmd_files calculation in top Makefile") because now we must check the presence of targets. Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-11-30 01:05:22 +00:00
# read saved command lines for existing targets
existing-targets := $(wildcard $(sort $(targets)))
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
endif # config-build
endif # mixed-build
endif # need-sub-make
PHONY += FORCE
FORCE:
# Declare the contents of the PHONY variable as phony. We keep that
# information in a variable so we can use it in if_changed and friends.
.PHONY: $(PHONY)