Commit b42d2306 authored by Masahiro Yamada's avatar Masahiro Yamada
Browse files

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: default avatarMasahiro Yamada <masahiroy@kernel.org>
Tested-by: Sedat Dilek <sedat.dilek@gmail.com> # LLVM-14 (x86-64)
parent 5d45950d

scripts/Makefile.build

+0 −26
Original line number Diff line number Diff line
@@ -210,38 +210,12 @@ cmd_record_mcount = $(if $(findstring $(strip $(CC_FLAGS_FTRACE)),$(_c_flags)), 
	$(sub_cmd_record_mcount))

endif # CONFIG_FTRACE_MCOUNT_USE_RECORDMCOUNT



ifdef CONFIG_OBJTOOL



objtool := $(objtree)/tools/objtool/objtool



objtool_args =								\

	$(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label)	\

	$(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr)		\

	$(if $(CONFIG_X86_KERNEL_IBT), --ibt)				\

	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)		\

	$(if $(CONFIG_UNWINDER_ORC), --orc)				\

	$(if $(CONFIG_RETPOLINE), --retpoline)				\

	$(if $(CONFIG_SLS), --sls)					\

	$(if $(CONFIG_STACK_VALIDATION), --stackval)			\

	$(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call)		\

	--uaccess							\

	$(if $(delay-objtool), --link)					\

	$(if $(part-of-module), --module)				\

	$(if $(CONFIG_GCOV_KERNEL), --no-unreachable)



cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)

cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)



endif # CONFIG_OBJTOOL



# 'OBJECT_FILES_NON_STANDARD := y': skip objtool checking for a directory

# 'OBJECT_FILES_NON_STANDARD_foo.o := 'y': skip objtool checking for a file

# 'OBJECT_FILES_NON_STANDARD_foo.o := 'n': override directory skip for a file



is-standard-object = $(if $(filter-out y%, $(OBJECT_FILES_NON_STANDARD_$(basetarget).o)$(OBJECT_FILES_NON_STANDARD)n),y)



delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))



$(obj)/%.o: objtool-enabled = $(if $(is-standard-object),$(if $(delay-objtool),$(is-single-obj-m),y))



ifdef CONFIG_TRIM_UNUSED_KSYMS

scripts/Makefile.lib

+26 −0
Original line number Diff line number Diff line
@@ -225,6 +225,32 @@ dtc_cpp_flags = -Wp,-MMD,$(depfile).pre.tmp -nostdinc \ 
		 $(addprefix -I,$(DTC_INCLUDE))                          \

		 -undef -D__DTS__



ifdef CONFIG_OBJTOOL



objtool := $(objtree)/tools/objtool/objtool



objtool_args =								\

	$(if $(CONFIG_HAVE_JUMP_LABEL_HACK), --hacks=jump_label)	\

	$(if $(CONFIG_HAVE_NOINSTR_HACK), --hacks=noinstr)		\

	$(if $(CONFIG_X86_KERNEL_IBT), --ibt)				\

	$(if $(CONFIG_FTRACE_MCOUNT_USE_OBJTOOL), --mcount)		\

	$(if $(CONFIG_UNWINDER_ORC), --orc)				\

	$(if $(CONFIG_RETPOLINE), --retpoline)				\

	$(if $(CONFIG_SLS), --sls)					\

	$(if $(CONFIG_STACK_VALIDATION), --stackval)			\

	$(if $(CONFIG_HAVE_STATIC_CALL_INLINE), --static-call)		\

	--uaccess							\

	$(if $(delay-objtool), --link)					\

	$(if $(part-of-module), --module)				\

	$(if $(CONFIG_GCOV_KERNEL), --no-unreachable)



delay-objtool := $(or $(CONFIG_LTO_CLANG),$(CONFIG_X86_KERNEL_IBT))



cmd_objtool = $(if $(objtool-enabled), ; $(objtool) $(objtool_args) $@)

cmd_gen_objtooldep = $(if $(objtool-enabled), { echo ; echo '$@: $$(wildcard $(objtool))' ; } >> $(dot-target).cmd)



endif # CONFIG_OBJTOOL



# Useful for describing the dependency of composite objects

# Usage:

#   $(call multi_depend, multi_used_targets, suffix_to_remove, suffix_to_add)

scripts/Makefile.vmlinux_o

+26 −0
Original line number Diff line number Diff line
@@ -6,6 +6,9 @@ __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

# ---------------------------------------------------------------------------
@@ -24,6 +27,27 @@ 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

# ---------------------------------------------------------------------------
@@ -33,9 +57,11 @@ quiet_cmd_ld_vmlinux.o = LD $@ 
	$(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

scripts/link-vmlinux.sh

+0 −71
Original line number Diff line number Diff line
@@ -45,76 +45,6 @@ info() 
	printf "  %-7s %s\n" "${1}" "${2}"

}



objtool_link()

{

	local objtoolcmd;

	local objtoolopt;



	if ! is_enabled CONFIG_OBJTOOL; then

		return;

	fi



	if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then



		# For LTO and IBT, objtool doesn't run on individual

		# translation units.  Run everything on vmlinux instead.



		if is_enabled CONFIG_HAVE_JUMP_LABEL_HACK; then

			objtoolopt="${objtoolopt} --hacks=jump_label"

		fi



		if is_enabled CONFIG_HAVE_NOINSTR_HACK; then

			objtoolopt="${objtoolopt} --hacks=noinstr"

		fi



		if is_enabled CONFIG_X86_KERNEL_IBT; then

			objtoolopt="${objtoolopt} --ibt"

		fi



		if is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL; then

			objtoolopt="${objtoolopt} --mcount"

		fi



		if is_enabled CONFIG_UNWINDER_ORC; then

			objtoolopt="${objtoolopt} --orc"

		fi



		if is_enabled CONFIG_RETPOLINE; then

			objtoolopt="${objtoolopt} --retpoline"

		fi



		if is_enabled CONFIG_SLS; then

			objtoolopt="${objtoolopt} --sls"

		fi



		if is_enabled CONFIG_STACK_VALIDATION; then

			objtoolopt="${objtoolopt} --stackval"

		fi



		if is_enabled CONFIG_HAVE_STATIC_CALL_INLINE; then

			objtoolopt="${objtoolopt} --static-call"

		fi



		objtoolopt="${objtoolopt} --uaccess"

	fi



	if is_enabled CONFIG_NOINSTR_VALIDATION; then

		objtoolopt="${objtoolopt} --noinstr"

	fi



	if [ -n "${objtoolopt}" ]; then



		if is_enabled CONFIG_GCOV_KERNEL; then

			objtoolopt="${objtoolopt} --no-unreachable"

		fi



		objtoolopt="${objtoolopt} --link"



		info OBJTOOL ${1}

		tools/objtool/objtool ${objtoolopt} ${1}

	fi

}



# Link of vmlinux

# ${1} - output file

# ${2}, ${3}, ... - optional extra .o files
@@ -298,7 +228,6 @@ ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1 


#link vmlinux.o

${MAKE} -f "${srctree}/scripts/Makefile.vmlinux_o"

objtool_link vmlinux.o



# Generate the list of in-tree objects in vmlinux

#