1#!/bin/sh 2# SPDX-License-Identifier: GPL-2.0 3# 4# link vmlinux 5# 6# vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS). 7# vmlinux.a contains objects that are linked unconditionally. 8# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally 9# (not within --whole-archive), and do not require symbol indexes added. 10# 11# vmlinux 12# ^ 13# | 14# +--< vmlinux.a 15# | 16# +--< $(KBUILD_VMLINUX_LIBS) 17# | +--< lib/lib.a + more 18# | 19# +-< ${kallsymso} (see description in KALLSYMS section) 20# 21# vmlinux version (uname -v) cannot be updated during normal 22# descending-into-subdirs phase since we do not yet know if we need to 23# update vmlinux. 24# Therefore this step is delayed until just before final link of vmlinux. 25# 26# System.map is generated to document addresses of all kernel symbols 27 28# Error out on error 29set -e 30 31LD="$1" 32KBUILD_LDFLAGS="$2" 33LDFLAGS_vmlinux="$3" 34VMLINUX="$4" 35 36is_enabled() { 37 grep -q "^$1=y" include/config/auto.conf 38} 39 40# Nice output in kbuild format 41# Will be supressed by "make -s" 42info() 43{ 44 printf " %-7s %s\n" "${1}" "${2}" 45} 46 47# Link of vmlinux 48# ${1} - output file 49vmlinux_link() 50{ 51 local output=${1} 52 local objs 53 local libs 54 local ld 55 local ldflags 56 local ldlibs 57 58 info LD ${output} 59 60 # skip output file argument 61 shift 62 63 if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT || 64 is_enabled CONFIG_KLP_BUILD; then 65 # Use vmlinux.o instead of performing the slow LTO link again. 66 objs=vmlinux.o 67 libs= 68 else 69 objs=vmlinux.a 70 libs="${KBUILD_VMLINUX_LIBS}" 71 fi 72 73 if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then 74 objs="${objs} .builtin-dtbs.o" 75 fi 76 77 objs="${objs} .vmlinux.export.o" 78 objs="${objs} init/version-timestamp.o" 79 80 if [ "${SRCARCH}" = "um" ]; then 81 wl=-Wl, 82 ld="${CC}" 83 ldflags="${CFLAGS_vmlinux}" 84 ldlibs="-lutil -lrt -lpthread" 85 else 86 wl= 87 ld="${LD}" 88 ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}" 89 ldlibs= 90 fi 91 92 ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}" 93 94 # The kallsyms linking does not need debug symbols included. 95 if [ -n "${strip_debug}" ] ; then 96 ldflags="${ldflags} ${wl}--strip-debug" 97 fi 98 99 if [ -n "${generate_map}" ]; then 100 ldflags="${ldflags} ${wl}-Map=vmlinux.map" 101 fi 102 103 ${ld} ${ldflags} -o ${output} \ 104 ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \ 105 ${wl}--start-group ${libs} ${wl}--end-group \ 106 ${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs} 107} 108 109# Create ${2}.o file with all symbols from the ${1} object file 110kallsyms() 111{ 112 local kallsymopt; 113 114 if is_enabled CONFIG_KALLSYMS_ALL; then 115 kallsymopt="${kallsymopt} --all-symbols" 116 fi 117 118 info KSYMS "${2}.S" 119 scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S" 120 121 info AS "${2}.o" 122 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ 123 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S" 124 125 kallsymso=${2}.o 126} 127 128# Perform kallsyms for the given temporary vmlinux. 129sysmap_and_kallsyms() 130{ 131 mksysmap "${1}" "${1}.syms" 132 kallsyms "${1}.syms" "${1}.kallsyms" 133 134 kallsyms_sysmap=${1}.syms 135} 136 137# Create map file with all symbols from ${1} 138# See mksymap for additional details 139mksysmap() 140{ 141 info NM ${2} 142 ${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}" 143} 144 145sorttable() 146{ 147 ${NM} -S ${1} > .tmp_vmlinux.nm-sort 148 ${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1} 149} 150 151cleanup() 152{ 153 rm -f .btf.* 154 rm -f .tmp_vmlinux.nm-sort 155 rm -f System.map 156 rm -f vmlinux 157 rm -f vmlinux.map 158} 159 160# Use "make V=1" to debug this script 161case "${KBUILD_VERBOSE}" in 162*1*) 163 set -x 164 ;; 165esac 166 167if [ "$1" = "clean" ]; then 168 cleanup 169 exit 0 170fi 171 172${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o 173 174arch_vmlinux_o= 175if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then 176 arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o 177fi 178 179btf_vmlinux_bin_o= 180btfids_vmlinux= 181kallsymso= 182strip_debug= 183generate_map= 184 185# Use "make UT=1" to trigger warnings on unused tracepoints 186case "${WARN_ON_UNUSED_TRACEPOINTS}" in 187*1*) 188 ${objtree}/scripts/tracepoint-update vmlinux.o 189 ;; 190esac 191 192if is_enabled CONFIG_KALLSYMS; then 193 true > .tmp_vmlinux0.syms 194 kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms 195fi 196 197if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then 198 199 # The kallsyms linking does not need debug symbols, but the BTF does. 200 if ! is_enabled CONFIG_DEBUG_INFO_BTF; then 201 strip_debug=1 202 fi 203 204 vmlinux_link .tmp_vmlinux1 205fi 206 207if is_enabled CONFIG_DEBUG_INFO_BTF; then 208 info BTF .tmp_vmlinux1 209 if ! ${CONFIG_SHELL} ${srctree}/scripts/gen-btf.sh .tmp_vmlinux1; then 210 echo >&2 "Failed to generate BTF for vmlinux" 211 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" 212 exit 1 213 fi 214 btf_vmlinux_bin_o=.tmp_vmlinux1.btf.o 215 btfids_vmlinux=.tmp_vmlinux1.BTF_ids 216fi 217 218if is_enabled CONFIG_KALLSYMS; then 219 220 # kallsyms support 221 # Generate section listing all symbols and add it into vmlinux 222 # It's a four step process: 223 # 0) Generate a dummy __kallsyms with empty symbol list. 224 # 1) Link .tmp_vmlinux1.kallsyms so it has all symbols and sections, 225 # with a dummy __kallsyms. 226 # Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with 227 # the right size 228 # 2) Link .tmp_vmlinux2.kallsyms so it now has a __kallsyms section of 229 # the right size, but due to the added section, some 230 # addresses have shifted. 231 # From here, we generate a correct .tmp_vmlinux2.kallsyms.o 232 # 3) That link may have expanded the kernel image enough that 233 # more linker branch stubs / trampolines had to be added, which 234 # introduces new names, which further expands kallsyms. Do another 235 # pass if that is the case. In theory it's possible this results 236 # in even more stubs, but unlikely. 237 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 238 # other bugs. 239 # 4) The correct ${kallsymso} is linked into the final vmlinux. 240 # 241 # a) Verify that the System.map from vmlinux matches the map from 242 # ${kallsymso}. 243 244 # The kallsyms linking does not need debug symbols included. 245 strip_debug=1 246 247 sysmap_and_kallsyms .tmp_vmlinux1 248 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 249 250 vmlinux_link .tmp_vmlinux2 251 sysmap_and_kallsyms .tmp_vmlinux2 252 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 253 254 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 255 vmlinux_link .tmp_vmlinux3 256 sysmap_and_kallsyms .tmp_vmlinux3 257 fi 258fi 259 260strip_debug= 261 262if is_enabled CONFIG_VMLINUX_MAP; then 263 generate_map=1 264fi 265 266vmlinux_link "${VMLINUX}" 267 268if is_enabled CONFIG_DEBUG_INFO_BTF; then 269 info BTFIDS ${VMLINUX} 270 ${RESOLVE_BTFIDS} --patch_btfids ${btfids_vmlinux} ${VMLINUX} 271fi 272 273mksysmap "${VMLINUX}" System.map 274 275if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then 276 info SORTTAB "${VMLINUX}" 277 if ! sorttable "${VMLINUX}"; then 278 echo >&2 Failed to sort kernel tables 279 exit 1 280 fi 281fi 282 283# step a (see comment above) 284if is_enabled CONFIG_KALLSYMS; then 285 if ! cmp -s System.map "${kallsyms_sysmap}"; then 286 echo >&2 Inconsistent kallsyms data 287 echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround' 288 exit 1 289 fi 290fi 291 292# For fixdep 293echo "${VMLINUX}: $0" > ".${VMLINUX}.d" 294