Commit 42640b13 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

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

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: default avatarMasahiro Yamada <masahiroy@kernel.org>
Acked-by: default avatarKees Cook <keescook@chromium.org>
parent 16a122c7

scripts/Makefile.build

+2 −2
Original line number Diff line number Diff line
@@ -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

scripts/Makefile.clean

+1 −2
Original line number Diff line number Diff line
@@ -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))

scripts/Makefile.host

+2 −28
Original line number Diff line number Diff line
@@ -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)
 
	   $(host-cxxmulti) $(host-cxxobjs)

scripts/gcc-plugins/Makefile

+50 −11
Original line number Diff line number Diff line 
# 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



# 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



always-y += $(GCC_PLUGIN)



hostcxxlibs-y := $(GCC_PLUGIN)

always-y := $(hostcxxlibs-y)

GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)



$(foreach p,$(hostcxxlibs-y:%.so=%),$(eval $(p)-objs := $(p).o))

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)

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