linux/scripts/Makefile.vmlinux_o
Masahiro Yamada b42d230650 kbuild: factor out the common objtool arguments
scripts/Makefile.build and scripts/link-vmlinux.sh have similar setups
for the objtool arguments.

It was difficult to factor out them because all the vmlinux build rules
were written in a shell script. It is somewhat tedious to touch the two
files every time a new objtool option is supported.

To reduce the code duplication, move the objtool for vmlinux.o into
scripts/Makefile.vmlinux_o. Then, move the common macros to Makefile.lib
so they are shared between Makefile.build and Makefile.vmlinux_o.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
2022-06-05 06:20:57 +09:00

88 lines
2.6 KiB
Makefile

# SPDX-License-Identifier: GPL-2.0-only
PHONY := __default
__default: vmlinux.o
include include/config/auto.conf
include $(srctree)/scripts/Kbuild.include
# for objtool
include $(srctree)/scripts/Makefile.lib
# Generate a linker script to ensure correct ordering of initcalls for Clang LTO
# ---------------------------------------------------------------------------
quiet_cmd_gen_initcalls_lds = GEN $@
cmd_gen_initcalls_lds = \
$(PYTHON3) $(srctree)/scripts/jobserver-exec \
$(PERL) $(real-prereqs) > $@
.tmp_initcalls.lds: $(srctree)/scripts/generate_initcall_order.pl \
$(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
$(call if_changed,gen_initcalls_lds)
targets := .tmp_initcalls.lds
ifdef CONFIG_LTO_CLANG
initcalls-lds := .tmp_initcalls.lds
endif
# objtool for vmlinux.o
# ---------------------------------------------------------------------------
#
# For LTO and IBT, objtool doesn't run on individual translation units.
# Run everything on vmlinux instead.
objtool-enabled := $(or $(delay-objtool),$(CONFIG_NOINSTR_VALIDATION))
# Reuse objtool_args defined in scripts/Makefile.lib if LTO or IBT is enabled.
#
# Add some more flags as needed.
# --no-unreachable and --link might be added twice, but it is fine.
#
# Expand objtool_args to a simple variable to avoid circular reference.
objtool_args := \
$(if $(delay-objtool),$(objtool_args)) \
$(if $(CONFIG_NOINSTR_VALIDATION), --noinstr) \
$(if $(CONFIG_GCOV_KERNEL), --no-unreachable) \
--link
# Link of vmlinux.o used for section mismatch analysis
# ---------------------------------------------------------------------------
quiet_cmd_ld_vmlinux.o = LD $@
cmd_ld_vmlinux.o = \
$(LD) ${KBUILD_LDFLAGS} -r -o $@ \
$(addprefix -T , $(initcalls-lds)) \
--whole-archive $(KBUILD_VMLINUX_OBJS) --no-whole-archive \
--start-group $(KBUILD_VMLINUX_LIBS) --end-group \
$(cmd_objtool)
define rule_ld_vmlinux.o
$(call cmd_and_savecmd,ld_vmlinux.o)
$(call cmd,gen_objtooldep)
endef
vmlinux.o: $(initcalls-lds) $(KBUILD_VMLINUX_OBJS) $(KBUILD_VMLINUX_LIBS) FORCE
$(call if_changed_rule,ld_vmlinux.o)
targets += vmlinux.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)