mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-23 17:30:02 +00:00
850ded46c6
With CONFIG_LTO_CLANG, we currently link modules into native code just before modpost, which means with TRIM_UNUSED_KSYMS enabled, we still look at the LLVM bitcode in the .o files when generating the list of used symbols. As the bitcode doesn't yet have calls to compiler intrinsics and llvm-nm doesn't see function references that only exist in function-level inline assembly, we currently need a whitelist for TRIM_UNUSED_KSYMS to work with LTO. This change moves module LTO linking to happen earlier, and thus avoids the issue with LLVM bitcode and TRIM_UNUSED_KSYMS entirely, allowing us to also drop the whitelist from gen_autoksyms.sh. Link: https://github.com/ClangBuiltLinux/linux/issues/1369 Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Alexander Lobakin <alobakin@pm.me> Tested-by: Alexander Lobakin <alobakin@pm.me> Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
81 lines
2.7 KiB
Makefile
81 lines
2.7 KiB
Makefile
# SPDX-License-Identifier: GPL-2.0-only
|
|
# ===========================================================================
|
|
# Module final link
|
|
# ===========================================================================
|
|
|
|
PHONY := __modfinal
|
|
__modfinal:
|
|
|
|
include include/config/auto.conf
|
|
include $(srctree)/scripts/Kbuild.include
|
|
|
|
# for c_flags and mod-prelink-ext
|
|
include $(srctree)/scripts/Makefile.lib
|
|
|
|
# find all modules listed in modules.order
|
|
modules := $(sort $(shell cat $(MODORDER)))
|
|
|
|
__modfinal: $(modules)
|
|
@:
|
|
|
|
# modname and part-of-module are set to make c_flags define proper module flags
|
|
modname = $(notdir $(@:.mod.o=))
|
|
part-of-module = y
|
|
|
|
quiet_cmd_cc_o_c = CC [M] $@
|
|
cmd_cc_o_c = $(CC) $(filter-out $(CC_FLAGS_CFI), $(c_flags)) -c -o $@ $<
|
|
|
|
%.mod.o: %.mod.c FORCE
|
|
$(call if_changed_dep,cc_o_c)
|
|
|
|
ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
|
|
|
|
quiet_cmd_ld_ko_o = LD [M] $@
|
|
cmd_ld_ko_o += \
|
|
$(LD) -r $(KBUILD_LDFLAGS) \
|
|
$(KBUILD_LDFLAGS_MODULE) $(LDFLAGS_MODULE) \
|
|
-T scripts/module.lds -o $@ $(filter %.o, $^); \
|
|
$(if $(ARCH_POSTLINK), $(MAKE) -f $(ARCH_POSTLINK) $@, true)
|
|
|
|
quiet_cmd_btf_ko = BTF [M] $@
|
|
cmd_btf_ko = \
|
|
if [ -f vmlinux ]; then \
|
|
LLVM_OBJCOPY="$(OBJCOPY)" $(PAHOLE) -J --btf_base vmlinux $@; \
|
|
else \
|
|
printf "Skipping BTF generation for %s due to unavailability of vmlinux\n" $@ 1>&2; \
|
|
fi;
|
|
|
|
# Same as newer-prereqs, but allows to exclude specified extra dependencies
|
|
newer_prereqs_except = $(filter-out $(PHONY) $(1),$?)
|
|
|
|
# Same as if_changed, but allows to exclude specified extra dependencies
|
|
if_changed_except = $(if $(call newer_prereqs_except,$(2))$(cmd-check), \
|
|
$(cmd); \
|
|
printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd, @:)
|
|
|
|
|
|
# Re-generate module BTFs if either module's .ko or vmlinux changed
|
|
$(modules): %.ko: %$(mod-prelink-ext).o %.mod.o scripts/module.lds $(if $(KBUILD_BUILTIN),vmlinux) FORCE
|
|
+$(call if_changed_except,ld_ko_o,vmlinux)
|
|
ifdef CONFIG_DEBUG_INFO_BTF_MODULES
|
|
+$(if $(newer-prereqs),$(call cmd,btf_ko))
|
|
endif
|
|
|
|
targets += $(modules) $(modules:.ko=.mod.o)
|
|
|
|
# Add FORCE to the prequisites of a target to force it to be always rebuilt.
|
|
# ---------------------------------------------------------------------------
|
|
|
|
PHONY += FORCE
|
|
FORCE:
|
|
|
|
# Read all saved command lines and dependencies for the $(targets) we
|
|
# may be building above, using $(if_changed{,_dep}). As an
|
|
# optimization, we don't need to read them if the target does not
|
|
# exist, we will rebuild anyway in that case.
|
|
|
|
existing-targets := $(wildcard $(sort $(targets)))
|
|
|
|
-include $(foreach f,$(existing-targets),$(dir $(f)).$(notdir $(f)).cmd)
|
|
|
|
.PHONY: $(PHONY)
|