#!/bin/sh# SPDX-License-Identifier: GPL-2.0## link vmlinux## vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_OBJS) and# $(KBUILD_VMLINUX_LIBS). Most are built-in.a files from top-level directories# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally# (not within --whole-archive), and do not require symbol indexes added.## vmlinux#   ^#   |#   +--< $(KBUILD_VMLINUX_OBJS)#   |    +--< init/built-in.a drivers/built-in.a mm/built-in.a + more#   |#   +--< $(KBUILD_VMLINUX_LIBS)#   |    +--< lib/lib.a + more#   |#   +-< ${kallsymso} (see description in KALLSYMS section)## vmlinux version (uname -v) cannot be updated during normal# descending-into-subdirs phase since we do not yet know if we need to# update vmlinux.# Therefore this step is delayed until just before final link of vmlinux.## System.map is generated to document addresses of all kernel symbols # Error out on errorset -e LD="$1"KBUILD_LDFLAGS="$2"LDFLAGS_vmlinux="$3" is_enabled() {	grep -q "^$1=y" include/config/auto.conf} # Nice output in kbuild format# Will be supressed by "make -s"info(){	printf "  %-7s %s\n" "${1}" "${2}"} # Generate a linker script to ensure correct ordering of initcalls.gen_initcalls(){	info GEN .tmp_initcalls.lds 	${PYTHON} ${srctree}/scripts/jobserver-exec		\	${PERL} ${srctree}/scripts/generate_initcall_order.pl	\		${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}	\		> .tmp_initcalls.lds} # If CONFIG_LTO_CLANG is selected, collect generated symbol versions into# .tmp_symversions.ldsgen_symversions(){	info GEN .tmp_symversions.lds	rm -f .tmp_symversions.lds 	for o in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do		if [ -f ${o}.symversions ]; then			cat ${o}.symversions >> .tmp_symversions.lds		fi	done} # Link of vmlinux.o used for section mismatch analysis# ${1} output filemodpost_link(){	local objects	local lds="" 	objects="--whole-archive				\		${KBUILD_VMLINUX_OBJS}				\		--no-whole-archive				\		--start-group					\		${KBUILD_VMLINUX_LIBS}				\		--end-group" 	if is_enabled CONFIG_LTO_CLANG; then		gen_initcalls		lds="-T .tmp_initcalls.lds" 		if is_enabled CONFIG_MODVERSIONS; then			gen_symversions			lds="${lds} -T .tmp_symversions.lds"		fi 		# This might take a while, so indicate that we're doing		# an LTO link		info LTO ${1}	else		info LD ${1}	fi 	${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${lds} ${objects}} objtool_link(){	local objtoolcmd;	local objtoolopt; 	if is_enabled CONFIG_LTO_CLANG && is_enabled CONFIG_STACK_VALIDATION; then		# Don't perform vmlinux validation unless explicitly requested,		# but run objtool on vmlinux.o now that we have an object file.		if is_enabled CONFIG_UNWINDER_ORC; then			objtoolcmd="orc generate"		fi 		objtoolopt="${objtoolopt} --duplicate" 		if is_enabled CONFIG_FTRACE_MCOUNT_USE_OBJTOOL; then			objtoolopt="${objtoolopt} --mcount"		fi	fi 	if is_enabled CONFIG_VMLINUX_VALIDATION; then		objtoolopt="${objtoolopt} --noinstr"	fi 	if [ -n "${objtoolopt}" ]; then		if [ -z "${objtoolcmd}" ]; then			objtoolcmd="check"		fi		objtoolopt="${objtoolopt} --vmlinux"		if ! is_enabled CONFIG_FRAME_POINTER; then			objtoolopt="${objtoolopt} --no-fp"		fi		if is_enabled CONFIG_GCOV_KERNEL || is_enabled CONFIG_LTO_CLANG; then			objtoolopt="${objtoolopt} --no-unreachable"		fi		if is_enabled CONFIG_RETPOLINE; then			objtoolopt="${objtoolopt} --retpoline"		fi		if is_enabled CONFIG_X86_SMAP; then			objtoolopt="${objtoolopt} --uaccess"		fi		if is_enabled CONFIG_SLS; then			objtoolopt="${objtoolopt} --sls"		fi		info OBJTOOL ${1}		tools/objtool/objtool ${objtoolcmd} ${objtoolopt} ${1}	fi} # Link of vmlinux# ${1} - output file# ${2}, ${3}, ... - optional extra .o filesvmlinux_link(){	local output=${1}	local objs	local libs	local ld	local ldflags	local ldlibs 	info LD ${output} 	# skip output file argument	shift 	if is_enabled CONFIG_LTO_CLANG; then		# Use vmlinux.o instead of performing the slow LTO link again.		objs=vmlinux.o		libs=	else		objs="${KBUILD_VMLINUX_OBJS}"		libs="${KBUILD_VMLINUX_LIBS}"	fi 	if [ "${SRCARCH}" = "um" ]; then		wl=-Wl,		ld="${CC}"		ldflags="${CFLAGS_vmlinux}"		ldlibs="-lutil -lrt -lpthread"	else		wl=		ld="${LD}"		ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"		ldlibs=	fi 	ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}" 	# The kallsyms linking does not need debug symbols included.	if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then		ldflags="${ldflags} ${wl}--strip-debug"	fi 	if is_enabled CONFIG_VMLINUX_MAP; then		ldflags="${ldflags} ${wl}-Map=${output}.map"	fi 	${ld} ${ldflags} -o ${output}					\		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\		${wl}--start-group ${libs} ${wl}--end-group		\		$@ ${ldlibs}} # generate .BTF typeinfo from DWARF debuginfo# ${1} - vmlinux image# ${2} - file to dump raw BTF data intogen_btf(){	local pahole_ver 	if ! [ -x "$(command -v ${PAHOLE})" ]; then		echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"		return 1	fi 	pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')	if [ "${pahole_ver}" -lt "116" ]; then		echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"		return 1	fi 	vmlinux_link ${1} 	info "BTF" ${2}	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} 	# Create ${2} which contains just .BTF section but no symbols. Add	# SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all	# deletes all symbols including __start_BTF and __stop_BTF, which will	# be redefined in the linker script. Add 2>/dev/null to suppress GNU	# objcopy warnings: "empty loadable segment detected at ..."	${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \		--strip-all ${1} ${2} 2>/dev/null	# Change e_type to ET_REL so that it can be used to link final vmlinux.	# Unlike GNU ld, lld does not allow an ET_EXEC input.	printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none} # Create ${2} .S file with all symbols from the ${1} object filekallsyms(){	local kallsymopt; 	if is_enabled CONFIG_KALLSYMS_ALL; then		kallsymopt="${kallsymopt} --all-symbols"	fi 	if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then		kallsymopt="${kallsymopt} --absolute-percpu"	fi 	if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then		kallsymopt="${kallsymopt} --base-relative"	fi 	info KSYMS ${2}	${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2}} # Perform one step in kallsyms generation, including temporary linking of# vmlinux.kallsyms_step(){	kallsymso_prev=${kallsymso}	kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}	kallsymso=${kallsyms_vmlinux}.o	kallsyms_S=${kallsyms_vmlinux}.S 	vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}	kallsyms ${kallsyms_vmlinux} ${kallsyms_S} 	info AS ${kallsyms_S}	${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \	      ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \	      -c -o ${kallsymso} ${kallsyms_S}} # Create map file with all symbols from ${1}# See mksymap for additional detailsmksysmap(){	${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}} sorttable(){	${objtree}/scripts/sorttable ${1}} # Delete output files in case of errorcleanup(){	rm -f .btf.*	rm -f .tmp_System.map	rm -f .tmp_initcalls.lds	rm -f .tmp_symversions.lds	rm -f .tmp_vmlinux*	rm -f System.map	rm -f vmlinux	rm -f vmlinux.map	rm -f vmlinux.o	rm -f .vmlinux.d} # Use "make V=1" to debug this scriptcase "${KBUILD_VERBOSE}" in*1*)	set -x	;;esac if [ "$1" = "clean" ]; then	cleanup	exit 0fi # Update versioninfo GEN .versionif [ -r .version ]; then	VERSION=$(expr 0$(cat .version) + 1)	echo $VERSION > .versionelse	rm -f .version	echo 1 > .versionfi; # final build of init/${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1 #link vmlinux.omodpost_link vmlinux.oobjtool_link vmlinux.o # modpost vmlinux.o to check for section mismatches${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1 info MODINFO modules.builtin.modinfo${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfoinfo GEN modules.builtin# The second line aids cases where multiple modules share the same object.tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |	tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin btf_vmlinux_bin_o=""if is_enabled CONFIG_DEBUG_INFO_BTF; then	btf_vmlinux_bin_o=.btf.vmlinux.bin.o	if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then		echo >&2 "Failed to generate BTF for vmlinux"		echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"		exit 1	fifi kallsymso=""kallsymso_prev=""kallsyms_vmlinux=""if is_enabled CONFIG_KALLSYMS; then 	# kallsyms support	# Generate section listing all symbols and add it into vmlinux	# It's a three step process:	# 1)  Link .tmp_vmlinux.kallsyms1 so it has all symbols and sections,	#     but __kallsyms is empty.	#     Running kallsyms on that gives us .tmp_kallsyms1.o with	#     the right size	# 2)  Link .tmp_vmlinux.kallsyms2 so it now has a __kallsyms section of	#     the right size, but due to the added section, some	#     addresses have shifted.	#     From here, we generate a correct .tmp_vmlinux.kallsyms2.o	# 3)  That link may have expanded the kernel image enough that	#     more linker branch stubs / trampolines had to be added, which	#     introduces new names, which further expands kallsyms. Do another	#     pass if that is the case. In theory it's possible this results	#     in even more stubs, but unlikely.	#     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around	#     other bugs.	# 4)  The correct ${kallsymso} is linked into the final vmlinux.	#	# a)  Verify that the System.map from vmlinux matches the map from	#     ${kallsymso}. 	kallsyms_step 1	kallsyms_step 2 	# step 3	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then		kallsyms_step 3	fifi vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} # fill in BTF IDsif is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then	info BTFIDS vmlinux	${RESOLVE_BTFIDS} vmlinuxfi info SYSMAP System.mapmksysmap vmlinux System.map if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then	info SORTTAB vmlinux	if ! sorttable vmlinux; then		echo >&2 Failed to sort kernel tables		exit 1	fifi # step a (see comment above)if is_enabled CONFIG_KALLSYMS; then	mksysmap ${kallsyms_vmlinux} .tmp_System.map 	if ! cmp -s System.map .tmp_System.map; then		echo >&2 Inconsistent kallsyms data		echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround		exit 1	fifi # For fixdepecho "vmlinux: $0" > .vmlinux.d