linux/scripts/gcc-plugins/Makefile
Sam James 5a6b64adc1 gcc-plugins: drop -std=gnu++11 to fix GCC 13 build
The latest GCC 13 snapshot (13.0.1 20230129) gives the following:
```
cc1: error: cannot load plugin ./scripts/gcc-plugins/randomize_layout_plugin.so
 :./scripts/gcc-plugins/randomize_layout_plugin.so: undefined symbol: tree_code_type
```

This ends up being because of https://gcc.gnu.org/git/gitweb.cgi?p=gcc.git;h=b0241ce6e37031
upstream in GCC which changes the visibility of some types used by the kernel's
plugin infrastructure like tree_code_type.

After discussion with the GCC folks, we found that the kernel needs to be building
plugins with the same flags used to build GCC - and GCC defaults to gnu++17
right now. The minimum GCC version needed to build the kernel is GCC 5.1
and GCC 5.1 already defaults to gnu++14 anyway, so just drop the flag, as
all GCCs that could be used to build GCC already default to an acceptable
version which was >= the version we forced via flags until now.

Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108634
Signed-off-by: Sam James <sam@gentoo.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20230201230009.2252783-1-sam@gentoo.org
2023-02-02 16:31:23 +00:00

69 lines
2.5 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0
$(obj)/randomize_layout_plugin.so: $(obj)/randomize_layout_seed.h
quiet_cmd_create_randomize_layout_seed = SEEDHDR $@
cmd_create_randomize_layout_seed = \
SEED=$$(cat $(filter-out FORCE,$^) </dev/null); \
echo '/*' > $@; \
echo ' * This file is automatically generated. Keep it private.' >> $@; \
echo ' * Exposing this value will expose the layout of randomized structures.' >> $@; \
echo ' */' >> $@; \
echo "const char *randstruct_seed = \"$$SEED\";" >> $@
$(obj)/randomize_layout_seed.h: $(objtree)/scripts/basic/randstruct.seed FORCE
$(call if_changed,create_randomize_layout_seed)
targets += randomize_layout_seed.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)
GCC_PLUGINS_DIR = $(shell $(CC) -print-file-name=plugin)
plugin_cxxflags = -Wp,-MMD,$(depfile) $(KBUILD_HOSTCXXFLAGS) -fPIC \
-include $(srctree)/include/linux/compiler-version.h \
-DPLUGIN_VERSION=$(call stringify,$(KERNELVERSION)) \
-I $(GCC_PLUGINS_DIR)/include -I $(obj) \
-fno-rtti -fno-exceptions -fasynchronous-unwind-tables \
-ggdb -Wno-narrowing -Wno-unused-variable \
-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)