#!/bin/sh# SPDX-License-Identifier: GPL-2.0## link vmlinux## vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS).# vmlinux.a contains objects that are linked unconditionally.# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally# (not within --whole-archive), and do not require symbol indexes added.## vmlinux#   ^#   |#   +--< vmlinux.a#   |#   +--< $(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"VMLINUX="$4" 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}"} # Link of vmlinux# ${1} - output filevmlinux_link(){	local output=${1}	local objs	local libs	local ld	local ldflags	local ldlibs 	info LD ${output} 	# skip output file argument	shift 	if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then		# Use vmlinux.o instead of performing the slow LTO link again.		objs=vmlinux.o		libs=	else		objs=vmlinux.a		libs="${KBUILD_VMLINUX_LIBS}"	fi 	if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then		objs="${objs} .builtin-dtbs.o"	fi 	if is_enabled CONFIG_MODULES; then		objs="${objs} .vmlinux.export.o"	fi 	objs="${objs} init/version-timestamp.o" 	if [ "${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}/${KBUILD_LDS}" 	# The kallsyms linking does not need debug symbols included.	if [ -n "${strip_debug}" ] ; then		ldflags="${ldflags} ${wl}--strip-debug"	fi 	if [ -n "${generate_map}" ];  then		ldflags="${ldflags} ${wl}-Map=vmlinux.map"	fi 	${ld} ${ldflags} -o ${output}					\		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\		${wl}--start-group ${libs} ${wl}--end-group		\		${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}} # generate .BTF typeinfo from DWARF debuginfo# ${1} - vmlinux imagegen_btf(){	local btf_data=${1}.btf.o 	info BTF "${btf_data}"	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} 	# Create ${btf_data} 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 ${1} "${btf_data}" 2>/dev/null	# Change e_type to ET_REL so that it can be used to link final vmlinux.	# GNU ld 2.35+ and lld do not allow an ET_EXEC input.	if is_enabled CONFIG_CPU_BIG_ENDIAN; then		et_rel='\0\1'	else		et_rel='\1\0'	fi	printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none 	btf_vmlinux_bin_o=${btf_data}} # Create ${2}.o file with all symbols from the ${1} object filekallsyms(){	local kallsymopt; 	if is_enabled CONFIG_KALLSYMS_ALL; then		kallsymopt="${kallsymopt} --all-symbols"	fi 	info KSYMS "${2}.S"	scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S" 	info AS "${2}.o"	${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \	      ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S" 	kallsymso=${2}.o} # Perform kallsyms for the given temporary vmlinux.sysmap_and_kallsyms(){	mksysmap "${1}" "${1}.syms"	kallsyms "${1}.syms" "${1}.kallsyms" 	kallsyms_sysmap=${1}.syms} # Create map file with all symbols from ${1}# See mksymap for additional detailsmksysmap(){	info NM ${2}	${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}"} sorttable(){	${NM} -S ${1} > .tmp_vmlinux.nm-sort	${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1}} cleanup(){	rm -f .btf.*	rm -f .tmp_vmlinux.nm-sort	rm -f System.map	rm -f vmlinux	rm -f vmlinux.map} # Use "make V=1" to debug this scriptcase "${KBUILD_VERBOSE}" in*1*)	set -x	;;esac if [ "$1" = "clean" ]; then	cleanup	exit 0fi ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o arch_vmlinux_o=if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then	arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.ofi btf_vmlinux_bin_o=kallsymso=strip_debug=generate_map= if is_enabled CONFIG_KALLSYMS; then	true > .tmp_vmlinux0.syms	kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsymsfi if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then 	# The kallsyms linking does not need debug symbols, but the BTF does.	if ! is_enabled CONFIG_DEBUG_INFO_BTF; then		strip_debug=1	fi 	vmlinux_link .tmp_vmlinux1fi if is_enabled CONFIG_DEBUG_INFO_BTF; then	if ! gen_btf .tmp_vmlinux1; then		echo >&2 "Failed to generate BTF for vmlinux"		echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"		exit 1	fifi if is_enabled CONFIG_KALLSYMS; then 	# kallsyms support	# Generate section listing all symbols and add it into vmlinux	# It's a four step process:	# 0)  Generate a dummy __kallsyms with empty symbol list.	# 1)  Link .tmp_vmlinux1.kallsyms so it has all symbols and sections,	#     with a dummy __kallsyms.	#     Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with	#     the right size	# 2)  Link .tmp_vmlinux2.kallsyms 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_vmlinux2.kallsyms.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	#     ${kallsymso}. 	# The kallsyms linking does not need debug symbols included.	strip_debug=1 	sysmap_and_kallsyms .tmp_vmlinux1	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 	vmlinux_link .tmp_vmlinux2	sysmap_and_kallsyms .tmp_vmlinux2	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then		vmlinux_link .tmp_vmlinux3		sysmap_and_kallsyms .tmp_vmlinux3	fifi strip_debug= if is_enabled CONFIG_VMLINUX_MAP; then	generate_map=1fi vmlinux_link "${VMLINUX}" # fill in BTF IDsif is_enabled CONFIG_DEBUG_INFO_BTF; then	info BTFIDS "${VMLINUX}"	RESOLVE_BTFIDS_ARGS=""	if is_enabled CONFIG_WERROR; then		RESOLVE_BTFIDS_ARGS=" --fatal_warnings "	fi	${RESOLVE_BTFIDS} ${RESOLVE_BTFIDS_ARGS} "${VMLINUX}"fi mksysmap "${VMLINUX}" System.map if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then	info SORTTAB "${VMLINUX}"	if ! sorttable "${VMLINUX}"; then		echo >&2 Failed to sort kernel tables		exit 1	fifi # step a (see comment above)if is_enabled CONFIG_KALLSYMS; then	if ! cmp -s System.map "${kallsyms_sysmap}"; 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"