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kbuild: move host .so build rules to scripts/gcc-plugins/Makefile

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The host shared library rules are currently implemented in
scripts/Makefile.host, but actually GCC-plugin is the only user of
them. (The VDSO .so files are built for the target by different
build rules) Hence, they do not need to be treewide available.

Move all the relevant build rules to scripts/gcc-plugins/Makefile.

I also optimized the build steps so *.so is directly built from .c
because every upstream plugin is compiled from a single source file.

I am still keeping the multi-file plugin support, which Kees Cook
mentioned might be needed by out-of-tree plugins.
(https://lkml.org/lkml/2019/1/11/1107)

If the plugin, foo.so, is compiled from two files foo.c and foo2.c,
then you can do like follows:

  foo-objs := foo.o foo2.o

Single-file plugins do not need the *-objs notation.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Kees Cook <keescook@chromium.org>
This commit is contained in:
Masahiro Yamada 2020-07-29 12:15:36 +09:00
parent 16a122c743
commit 42640b134b
4 changed files with 55 additions and 43 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
scripts/Makefile.build
View File

@ -45,8 +45,8 @@ include $(kbuild-file)
include scripts/Makefile.lib
# Do not include host rules unless needed
ifneq ($(hostprogs)$(hostcxxlibs-y)$(hostcxxlibs-m),)
# Do not include hostprogs rules unless needed
ifneq ($(hostprogs),)
include scripts/Makefile.host
endif

3
scripts/Makefile.clean
View File

@ -29,8 +29,7 @@ subdir-ymn := $(addprefix $(obj)/,$(subdir-ymn))
__clean-files := $(extra-y) $(extra-m) $(extra-) \
$(always) $(always-y) $(always-m) $(always-) $(targets) $(clean-files) \
$(hostprogs) $(hostprogs-y) $(hostprogs-m) $(hostprogs-) $(userprogs) \
$(hostcxxlibs-y) $(hostcxxlibs-m)
$(hostprogs) $(hostprogs-y) $(hostprogs-m) $(hostprogs-) $(userprogs)
__clean-files := $(filter-out $(no-clean-files), $(__clean-files))

30
scripts/Makefile.host
View File

@ -39,7 +39,6 @@ $(obj)/%.tab.c $(obj)/%.tab.h: $(src)/%.y FORCE
# They are linked as C++ code to the executable qconf
__hostprogs := $(sort $(hostprogs))
host-cxxshlib := $(sort $(hostcxxlibs-y) $(hostcxxlibs-m))
# C code
# Executables compiled from a single .c file
@ -61,16 +60,11 @@ host-cxxmulti := $(foreach m,$(__hostprogs),$(if $($(m)-cxxobjs),$(m)))
# C++ Object (.o) files compiled from .cc files
host-cxxobjs := $(sort $(foreach m,$(host-cxxmulti),$($(m)-cxxobjs)))
# Object (.o) files used by the shared libaries
host-cxxshobjs := $(sort $(foreach m,$(host-cxxshlib),$($(m:.so=-objs))))
host-csingle := $(addprefix $(obj)/,$(host-csingle))
host-cmulti := $(addprefix $(obj)/,$(host-cmulti))
host-cobjs := $(addprefix $(obj)/,$(host-cobjs))
host-cxxmulti := $(addprefix $(obj)/,$(host-cxxmulti))
host-cxxobjs := $(addprefix $(obj)/,$(host-cxxobjs))
host-cxxshlib := $(addprefix $(obj)/,$(host-cxxshlib))
host-cxxshobjs := $(addprefix $(obj)/,$(host-cxxshobjs))
#####
# Handle options to gcc. Support building with separate output directory
@ -136,25 +130,5 @@ quiet_cmd_host-cxxobjs = HOSTCXX $@
$(host-cxxobjs): $(obj)/%.o: $(src)/%.cc FORCE
$(call if_changed_dep,host-cxxobjs)
# Compile .c file, create position independent .o file
# Note that plugin capable gcc versions can be either C or C++ based
# therefore plugin source files have to be compilable in both C and C++ mode.
# This is why a C++ compiler is invoked on a .c file.
# host-cxxshobjs -> .o
quiet_cmd_host-cxxshobjs = HOSTCXX -fPIC $@
cmd_host-cxxshobjs = $(HOSTCXX) $(hostcxx_flags) -fPIC -c -o $@ $<
$(host-cxxshobjs): $(obj)/%.o: $(src)/%.c FORCE
$(call if_changed_dep,host-cxxshobjs)
# Link a shared library, based on position independent .o files
# *.o -> .so shared library (host-cxxshlib)
quiet_cmd_host-cxxshlib = HOSTLLD -shared $@
cmd_host-cxxshlib = $(HOSTCXX) $(KBUILD_HOSTLDFLAGS) -shared -o $@ \
$(addprefix $(obj)/, $($(target-stem)-objs)) \
$(KBUILD_HOSTLDLIBS) $(HOSTLDLIBS_$(target-stem).so)
$(host-cxxshlib): FORCE
$(call if_changed,host-cxxshlib)
$(call multi_depend, $(host-cxxshlib), .so, -objs)
targets += $(host-csingle) $(host-cmulti) $(host-cobjs)\
$(host-cxxmulti) $(host-cxxobjs) $(host-cxxshlib) $(host-cxxshobjs)
targets += $(host-csingle) $(host-cmulti) $(host-cobjs) \
$(host-cxxmulti) $(host-cxxobjs)

61
scripts/gcc-plugins/Makefile
View File

@ -1,22 +1,61 @@
# SPDX-License-Identifier: GPL-2.0
GCC_PLUGINS_DIR := $(shell $(CC) -print-file-name=plugin)
HOST_EXTRACXXFLAGS += -I$(GCC_PLUGINS_DIR)/include -I$(src) -std=gnu++98 -fno-rtti
HOST_EXTRACXXFLAGS += -fno-exceptions -fasynchronous-unwind-tables -ggdb
HOST_EXTRACXXFLAGS += -Wno-narrowing -Wno-unused-variable -Wno-c++11-compat
HOST_EXTRACXXFLAGS += -Wno-format-diag
$(obj)/randomize_layout_plugin.o: $(objtree)/$(obj)/randomize_layout_seed.h
$(obj)/randomize_layout_plugin.so: $(objtree)/$(obj)/randomize_layout_seed.h
quiet_cmd_create_randomize_layout_seed = GENSEED $@
cmd_create_randomize_layout_seed = \
$(CONFIG_SHELL) $(srctree)/$(src)/gen-random-seed.sh $@ $(objtree)/include/generated/randomize_layout_hash.h
$(objtree)/$(obj)/randomize_layout_seed.h: FORCE
$(call if_changed,create_randomize_layout_seed)
targets = randomize_layout_seed.h randomize_layout_hash.h
targets += randomize_layout_seed.h randomize_layout_hash.h
hostcxxlibs-y := $(GCC_PLUGIN)
always-y := $(hostcxxlibs-y)
# Build rules for plugins
#
# No extra code is needed for single-file plugins.
# For multi-file plugins, use *-objs syntax to list the objects.
#
# If the plugin foo.so is compiled from foo.c and foo2.c, you can do:
#
# foo-objs := foo.o foo2.o
$(foreach p,$(hostcxxlibs-y:%.so=%),$(eval $(p)-objs := $(p).o))
always-y += $(GCC_PLUGIN)
GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
-I $(GCC_PLUGINS_DIR)/include -I $(obj) -std=gnu++98 \
-fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
-ggdb -Wno-narrowing -Wno-unused-variable -Wno-c++11-compat \
-Wno-format-diag
plugin_ldflags = -shared
plugin-single := $(foreach m, $(GCC_PLUGIN), $(if $($(m:%.so=%-objs)),,$(m)))
plugin-multi := $(filter-out $(plugin-single), $(GCC_PLUGIN))
plugin-objs := $(sort $(foreach m, $(plugin-multi), $($(m:%.so=%-objs))))
targets += $(plugin-single) $(plugin-multi) $(plugin-objs)
clean-files += *.so
plugin-single := $(addprefix $(obj)/, $(plugin-single))
plugin-multi := $(addprefix $(obj)/, $(plugin-multi))
plugin-objs := $(addprefix $(obj)/, $(plugin-objs))
quiet_cmd_plugin_cxx_so_c = HOSTCXX $@
cmd_plugin_cxx_so_c = $(HOSTCXX) $(plugin_cxxflags) $(plugin_ldflags) -o $@ $<
$(plugin-single): $(obj)/%.so: $(src)/%.c FORCE
$(call if_changed_dep,plugin_cxx_so_c)
quiet_cmd_plugin_ld_so_o = HOSTLD $@
cmd_plugin_ld_so_o = $(HOSTCXX) $(plugin_ldflags) -o $@ \
$(addprefix $(obj)/, $($(target-stem)-objs))
$(plugin-multi): FORCE
$(call if_changed,plugin_ld_so_o)
$(foreach m, $(notdir $(plugin-multi)), $(eval $(obj)/$m: $(addprefix $(obj)/, $($(m:%.so=%-objs)))))
quiet_cmd_plugin_cxx_o_c = HOSTCXX $@
cmd_plugin_cxx_o_c = $(HOSTCXX) $(plugin_cxxflags) -c -o $@ $<
$(plugin-objs): $(obj)/%.o: $(src)/%.c FORCE
$(call if_changed_dep,plugin_cxx_o_c)