Kbuild updates for v4.13

- Clean up Makefiles and scripts
 
 - Improve clang support
 
 - Remove unneeded genhdr-y syntax
 
 - Remove unneeded cc-option-align macro
 
 - Introduce __cc-option macro and use it to fix x86 boot code compiler flags
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Merge tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild

Pull Kbuild updates from Masahiro Yamada:

 - Clean up Makefiles and scripts

 - Improve clang support

 - Remove unneeded genhdr-y syntax

 - Remove unneeded cc-option-align macro

 - Introduce __cc-option macro and use it to fix x86 boot code compiler
   flags

* tag 'kbuild-v4.13' of git://git.kernel.org/pub/scm/linux/kernel/git/masahiroy/linux-kbuild:
  kbuild: improve comments on KBUILD_SRC
  x86/build: Specify stack alignment for clang
  x86/build: Use __cc-option for boot code compiler options
  kbuild: Add __cc-option macro
  kbuild: remove cc-option-align
  kbuild: replace genhdr-y with generated-y
  kbuild: clang: Disable 'address-of-packed-member' warning
  kbuild: remove duplicated arch/*/include/generated/uapi include path
  kbuild: speed up checksyscalls.sh
  kbuild: simplify silent build (-s) detection
This commit is contained in:
Linus Torvalds 2017-07-07 14:09:24 -07:00
commit 58f051fc98
12 changed files with 67 additions and 104 deletions

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@ -45,10 +45,9 @@ This document describes the Linux kernel Makefiles.
=== 7 Kbuild syntax for exported headers
--- 7.1 no-export-headers
--- 7.2 genhdr-y
--- 7.3 generic-y
--- 7.4 generated-y
--- 7.5 mandatory-y
--- 7.2 generic-y
--- 7.3 generated-y
--- 7.4 mandatory-y
=== 8 Kbuild Variables
=== 9 Makefile language
@ -487,22 +486,6 @@ more details, with real examples.
respectively.
Note: cc-option-yn uses KBUILD_CFLAGS for $(CC) options
cc-option-align
gcc versions >= 3.0 changed the type of options used to specify
alignment of functions, loops etc. $(cc-option-align), when used
as prefix to the align options, will select the right prefix:
gcc < 3.00
cc-option-align = -malign
gcc >= 3.00
cc-option-align = -falign
Example:
KBUILD_CFLAGS += $(cc-option-align)-functions=4
In the above example, the option -falign-functions=4 is used for
gcc >= 3.00. For gcc < 3.00, -malign-functions=4 is used.
Note: cc-option-align uses KBUILD_CFLAGS for $(CC) options
cc-disable-warning
cc-disable-warning checks if gcc supports a given warning and returns
the commandline switch to disable it. This special function is needed,
@ -1277,18 +1260,7 @@ See subsequent chapter for the syntax of the Kbuild file.
avoid exporting specific headers (e.g. kvm.h) on architectures that do
not support it. It should be avoided as much as possible.
--- 7.2 genhdr-y
genhdr-y specifies asm files to be generated.
Example:
#arch/x86/include/uapi/asm/Kbuild
genhdr-y += unistd_32.h
genhdr-y += unistd_64.h
genhdr-y += unistd_x32.h
--- 7.3 generic-y
--- 7.2 generic-y
If an architecture uses a verbatim copy of a header from
include/asm-generic then this is listed in the file
@ -1315,11 +1287,10 @@ See subsequent chapter for the syntax of the Kbuild file.
Example: termios.h
#include <asm-generic/termios.h>
--- 7.4 generated-y
--- 7.3 generated-y
If an architecture generates other header files alongside generic-y
wrappers, and not included in genhdr-y, then generated-y specifies
them.
wrappers, generated-y specifies them.
This prevents them being treated as stale asm-generic wrappers and
removed.

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@ -84,17 +84,10 @@ endif
# If the user is running make -s (silent mode), suppress echoing of
# commands
ifneq ($(filter 4.%,$(MAKE_VERSION)),) # make-4
ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
quiet=silent_
tools_silent=s
endif
else # make-3.8x
ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
quiet=silent_
tools_silent=-s
endif
endif
export quiet Q KBUILD_VERBOSE
@ -113,8 +106,8 @@ export quiet Q KBUILD_VERBOSE
# The O= assignment takes precedence over the KBUILD_OUTPUT environment
# variable.
# KBUILD_SRC is set on invocation of make in OBJ directory
# KBUILD_SRC is not intended to be used by the regular user (for now)
# KBUILD_SRC is not intended to be used by the regular user (for now),
# it is set on invocation of make with KBUILD_OUTPUT or O= specified.
ifeq ($(KBUILD_SRC),)
# OK, Make called in directory where kernel src resides
@ -135,7 +128,6 @@ ifneq ($(words $(subst :, ,$(CURDIR))), 1)
endif
ifneq ($(KBUILD_OUTPUT),)
# Invoke a second make in the output directory, passing relevant variables
# check that the output directory actually exists
saved-output := $(KBUILD_OUTPUT)
KBUILD_OUTPUT := $(shell mkdir -p $(KBUILD_OUTPUT) && cd $(KBUILD_OUTPUT) \
@ -148,6 +140,7 @@ PHONY += $(MAKECMDGOALS) sub-make
$(filter-out _all sub-make $(CURDIR)/Makefile, $(MAKECMDGOALS)) _all: sub-make
@:
# Invoke a second make in the output directory, passing relevant variables
sub-make:
$(Q)$(MAKE) -C $(KBUILD_OUTPUT) KBUILD_SRC=$(CURDIR) \
-f $(CURDIR)/Makefile $(filter-out _all sub-make,$(MAKECMDGOALS))
@ -303,7 +296,7 @@ CONFIG_SHELL := $(shell if [ -x "$$BASH" ]; then echo $$BASH; \
HOSTCC = gcc
HOSTCXX = g++
HOSTCFLAGS = -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89
HOSTCFLAGS := -Wall -Wmissing-prototypes -Wstrict-prototypes -O2 -fomit-frame-pointer -std=gnu89
HOSTCXXFLAGS = -O2
ifeq ($(shell $(HOSTCC) -v 2>&1 | grep -c "clang version"), 1)
@ -388,12 +381,10 @@ USERINCLUDE := \
# Needed to be compatible with the O= option
LINUXINCLUDE := \
-I$(srctree)/arch/$(hdr-arch)/include \
-I$(objtree)/arch/$(hdr-arch)/include/generated/uapi \
-I$(objtree)/arch/$(hdr-arch)/include/generated \
$(if $(KBUILD_SRC), -I$(srctree)/include) \
-I$(objtree)/include
LINUXINCLUDE += $(filter-out $(LINUXINCLUDE),$(USERINCLUDE))
-I$(objtree)/include \
$(USERINCLUDE)
KBUILD_CPPFLAGS := -D__KERNEL__
@ -707,6 +698,7 @@ KBUILD_CPPFLAGS += $(call cc-option,-Qunused-arguments,)
KBUILD_CFLAGS += $(call cc-disable-warning, unused-variable)
KBUILD_CFLAGS += $(call cc-disable-warning, format-invalid-specifier)
KBUILD_CFLAGS += $(call cc-disable-warning, gnu)
KBUILD_CFLAGS += $(call cc-disable-warning, address-of-packed-member)
# Quiet clang warning: comparison of unsigned expression < 0 is always false
KBUILD_CFLAGS += $(call cc-disable-warning, tautological-compare)
# CLANG uses a _MergedGlobals as optimization, but this breaks modpost, as the

View File

@ -1,8 +1,8 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm
genhdr-y += unistd-common.h
genhdr-y += unistd-oabi.h
genhdr-y += unistd-eabi.h
generated-y += unistd-common.h
generated-y += unistd-oabi.h
generated-y += unistd-eabi.h
generic-y += siginfo.h

View File

@ -11,6 +11,14 @@ else
KBUILD_DEFCONFIG := $(ARCH)_defconfig
endif
# For gcc stack alignment is specified with -mpreferred-stack-boundary,
# clang has the option -mstack-alignment for that purpose.
ifneq ($(call cc-option, -mpreferred-stack-boundary=4),)
cc_stack_align_opt := -mpreferred-stack-boundary
else ifneq ($(call cc-option, -mstack-alignment=4),)
cc_stack_align_opt := -mstack-alignment
endif
# How to compile the 16-bit code. Note we always compile for -march=i386;
# that way we can complain to the user if the CPU is insufficient.
#
@ -24,10 +32,11 @@ REALMODE_CFLAGS := $(M16_CFLAGS) -g -Os -D__KERNEL__ \
-DDISABLE_BRANCH_PROFILING \
-Wall -Wstrict-prototypes -march=i386 -mregparm=3 \
-fno-strict-aliasing -fomit-frame-pointer -fno-pic \
-mno-mmx -mno-sse \
$(call cc-option, -ffreestanding) \
$(call cc-option, -fno-stack-protector) \
$(call cc-option, -mpreferred-stack-boundary=2)
-mno-mmx -mno-sse
REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -ffreestanding)
REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), -fno-stack-protector)
REALMODE_CFLAGS += $(call __cc-option, $(CC), $(REALMODE_CFLAGS), $(cc_stack_align_opt)=2)
export REALMODE_CFLAGS
# BITS is used as extension for files which are available in a 32 bit
@ -64,8 +73,10 @@ ifeq ($(CONFIG_X86_32),y)
# with nonstandard options
KBUILD_CFLAGS += -fno-pic
# prevent gcc from keeping the stack 16 byte aligned
KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=2)
# Align the stack to the register width instead of using the default
# alignment of 16 bytes. This reduces stack usage and the number of
# alignment instructions.
KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align_opt)=2)
# Disable unit-at-a-time mode on pre-gcc-4.0 compilers, it makes gcc use
# a lot more stack due to the lack of sharing of stacklots:
@ -97,8 +108,14 @@ else
KBUILD_CFLAGS += $(call cc-option,-mno-80387)
KBUILD_CFLAGS += $(call cc-option,-mno-fp-ret-in-387)
# Use -mpreferred-stack-boundary=3 if supported.
KBUILD_CFLAGS += $(call cc-option,-mpreferred-stack-boundary=3)
# By default gcc and clang use a stack alignment of 16 bytes for x86.
# However the standard kernel entry on x86-64 leaves the stack on an
# 8-byte boundary. If the compiler isn't informed about the actual
# alignment it will generate extra alignment instructions for the
# default alignment which keep the stack *mis*aligned.
# Furthermore an alignment to the register width reduces stack usage
# and the number of alignment instructions.
KBUILD_CFLAGS += $(call cc-option,$(cc_stack_align_opt)=3)
# Use -mskip-rax-setup if supported.
KBUILD_CFLAGS += $(call cc-option,-mskip-rax-setup)

View File

@ -9,7 +9,6 @@ else
tune = $(call cc-option,-mcpu=$(1),$(2))
endif
align := $(cc-option-align)
cflags-$(CONFIG_M486) += -march=i486
cflags-$(CONFIG_M586) += -march=i586
cflags-$(CONFIG_M586TSC) += -march=i586
@ -24,11 +23,11 @@ cflags-$(CONFIG_MK6) += -march=k6
# They make zero difference whatsosever to performance at this time.
cflags-$(CONFIG_MK7) += -march=athlon
cflags-$(CONFIG_MK8) += $(call cc-option,-march=k8,-march=athlon)
cflags-$(CONFIG_MCRUSOE) += -march=i686 $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
cflags-$(CONFIG_MCRUSOE) += -march=i686 -falign-functions=0 -falign-jumps=0 -falign-loops=0
cflags-$(CONFIG_MEFFICEON) += -march=i686 $(call tune,pentium3) -falign-functions=0 -falign-jumps=0 -falign-loops=0
cflags-$(CONFIG_MWINCHIPC6) += $(call cc-option,-march=winchip-c6,-march=i586)
cflags-$(CONFIG_MWINCHIP3D) += $(call cc-option,-march=winchip2,-march=i586)
cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) $(align)-functions=0 $(align)-jumps=0 $(align)-loops=0
cflags-$(CONFIG_MCYRIXIII) += $(call cc-option,-march=c3,-march=i486) -falign-functions=0 -falign-jumps=0 -falign-loops=0
cflags-$(CONFIG_MVIAC3_2) += $(call cc-option,-march=c3-2,-march=i686)
cflags-$(CONFIG_MVIAC7) += -march=i686
cflags-$(CONFIG_MCORE2) += -march=i686 $(call tune,core2)

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@ -1,6 +1,6 @@
# UAPI Header export list
include include/uapi/asm-generic/Kbuild.asm
genhdr-y += unistd_32.h
genhdr-y += unistd_64.h
genhdr-y += unistd_x32.h
generated-y += unistd_32.h
generated-y += unistd_64.h
generated-y += unistd_x32.h

View File

@ -108,6 +108,11 @@ as-option = $(call try-run,\
as-instr = $(call try-run,\
printf "%b\n" "$(1)" | $(CC) $(KBUILD_AFLAGS) -c -x assembler -o "$$TMP" -,$(2),$(3))
# __cc-option
# Usage: MY_CFLAGS += $(call __cc-option,$(CC),$(MY_CFLAGS),-march=winchip-c6,-march=i586)
__cc-option = $(call try-run,\
$(1) -Werror $(2) $(3) -c -x c /dev/null -o "$$TMP",$(3),$(4))
# Do not attempt to build with gcc plugins during cc-option tests.
# (And this uses delayed resolution so the flags will be up to date.)
CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
@ -115,19 +120,19 @@ CC_OPTION_CFLAGS = $(filter-out $(GCC_PLUGINS_CFLAGS),$(KBUILD_CFLAGS))
# cc-option
# Usage: cflags-y += $(call cc-option,-march=winchip-c6,-march=i586)
cc-option = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
cc-option = $(call __cc-option, $(CC),\
$(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS),$(1),$(2))
# hostcc-option
# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
hostcc-option = $(call __cc-option, $(HOSTCC),\
$(HOSTCFLAGS) $(HOST_EXTRACFLAGS),$(1),$(2))
# cc-option-yn
# Usage: flag := $(call cc-option-yn,-march=winchip-c6)
cc-option-yn = $(call try-run,\
$(CC) -Werror $(KBUILD_CPPFLAGS) $(CC_OPTION_CFLAGS) $(1) -c -x c /dev/null -o "$$TMP",y,n)
# cc-option-align
# Prefix align with either -falign or -malign
cc-option-align = $(subst -functions=0,,\
$(call cc-option,-falign-functions=0,-malign-functions=0))
# cc-disable-warning
# Usage: cflags-y += $(call cc-disable-warning,unused-but-set-variable)
cc-disable-warning = $(call try-run,\

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@ -15,7 +15,7 @@ _dummy := $(shell [ -d $(obj) ] || mkdir -p $(obj))
# Stale wrappers when the corresponding files are removed from generic-y
# need removing.
generated-y := $(generic-y) $(genhdr-y) $(generated-y)
generated-y := $(generic-y) $(generated-y)
all-files := $(patsubst %, $(obj)/%, $(generated-y))
old-headers := $(wildcard $(obj)/*.h)
unwanted := $(filter-out $(all-files),$(old-headers))

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@ -20,12 +20,6 @@
# Will compile qconf as a C++ program, and menu as a C program.
# They are linked as C++ code to the executable qconf
# hostcc-option
# Usage: cflags-y += $(call hostcc-option,-march=winchip-c6,-march=i586)
hostcc-option = $(call try-run,\
$(HOSTCC) $(HOSTCFLAGS) $(HOST_EXTRACFLAGS) $(1) -c -x c /dev/null -o "$$TMP",$(1),$(2))
__hostprogs := $(sort $(hostprogs-y) $(hostprogs-m))
host-cshlib := $(sort $(hostlibs-y) $(hostlibs-m))
host-cxxshlib := $(sort $(hostcxxlibs-y) $(hostcxxlibs-m))

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@ -202,15 +202,12 @@ EOF
}
syscall_list() {
grep '^[0-9]' "$1" | sort -n | (
grep '^[0-9]' "$1" | sort -n |
while read nr abi name entry ; do
cat <<EOF
#if !defined(__NR_${name}) && !defined(__IGNORE_${name})
#warning syscall ${name} not implemented
#endif
EOF
echo "#if !defined(__NR_${name}) && !defined(__IGNORE_${name})"
echo "#warning syscall ${name} not implemented"
echo "#endif"
done
)
}
(ignore_list && syscall_list $(dirname $0)/../arch/x86/entry/syscalls/syscall_32.tbl) | \

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@ -19,15 +19,9 @@ else
Q=@
endif
ifneq ($(filter 4.%,$(MAKE_VERSION)),) # make-4
ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
quiet=silent_
endif
else # make-3.8x
ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
quiet=silent_
endif
endif
build-dir := $(srctree)/tools/build

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@ -58,15 +58,9 @@ else
NO_SUBDIR = :
endif
ifneq ($(filter 4.%,$(MAKE_VERSION)),) # make-4
ifneq ($(filter %s ,$(firstword x$(MAKEFLAGS))),)
ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
silent=1
endif
else # make-3.8x
ifneq ($(filter s% -s%,$(MAKEFLAGS)),)
silent=1
endif
endif
#
# Define a callable command for descending to a new directory