mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-12-14 06:24:53 +08:00
b1a1a1a09b
With LTO, LLVM bitcode won't be compiled into native code until modpost_link, or modfinal for modules. This change postpones calls to objtool until after these steps, and moves objtool_args to Makefile.lib, so the arguments can be reused in Makefile.modfinal. As we didn't have objects to process earlier, we use --duplicate when processing vmlinux.o. This change also disables unreachable instruction warnings with LTO to avoid warnings about the int3 padding between functions. Signed-off-by: Sami Tolvanen <samitolvanen@google.com> Reviewed-by: Kees Cook <keescook@chromium.org>
101 lines
3.2 KiB
Makefile
101 lines
3.2 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 objtool_args
|
|
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) $(c_flags) -c -o $@ $<
|
|
|
|
%.mod.o: %.mod.c FORCE
|
|
$(call if_changed_dep,cc_o_c)
|
|
|
|
ARCH_POSTLINK := $(wildcard $(srctree)/arch/$(SRCARCH)/Makefile.postlink)
|
|
|
|
ifdef CONFIG_LTO_CLANG
|
|
# With CONFIG_LTO_CLANG, reuse the object file we compiled for modpost to
|
|
# avoid a second slow LTO link
|
|
prelink-ext := .lto
|
|
|
|
# ELF processing was skipped earlier because we didn't have native code,
|
|
# so let's now process the prelinked binary before we link the module.
|
|
|
|
ifdef CONFIG_STACK_VALIDATION
|
|
ifneq ($(SKIP_STACK_VALIDATION),1)
|
|
cmd_ld_ko_o += \
|
|
$(objtree)/tools/objtool/objtool $(objtool_args) \
|
|
$(@:.ko=$(prelink-ext).o);
|
|
|
|
endif # SKIP_STACK_VALIDATION
|
|
endif # CONFIG_STACK_VALIDATION
|
|
|
|
endif # CONFIG_LTO_CLANG
|
|
|
|
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
|
|
$(modules): %.ko: %$(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)
|