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 if is_enabled CONFIG_64BIT || is_enabled CONFIG_RELOCATABLE; then 119 kallsymopt="${kallsymopt} --pc-relative" 120 fi 121 122 info KSYMS "${2}.S" 123 scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S" 124 125 info AS "${2}.o" 126 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ 127 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S" 128 129 kallsymso=${2}.o 130} 131 132# Perform kallsyms for the given temporary vmlinux. 133sysmap_and_kallsyms() 134{ 135 mksysmap "${1}" "${1}.syms" 136 kallsyms "${1}.syms" "${1}.kallsyms" 137 138 kallsyms_sysmap=${1}.syms 139} 140 141# Create map file with all symbols from ${1} 142# See mksymap for additional details 143mksysmap() 144{ 145 info NM ${2} 146 ${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}" 147} 148 149sorttable() 150{ 151 ${NM} -S ${1} > .tmp_vmlinux.nm-sort 152 ${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1} 153} 154 155cleanup() 156{ 157 rm -f .btf.* 158 rm -f .tmp_vmlinux.nm-sort 159 rm -f System.map 160 rm -f vmlinux 161 rm -f vmlinux.map 162} 163 164# Use "make V=1" to debug this script 165case "${KBUILD_VERBOSE}" in 166*1*) 167 set -x 168 ;; 169esac 170 171if [ "$1" = "clean" ]; then 172 cleanup 173 exit 0 174fi 175 176${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o 177 178arch_vmlinux_o= 179if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then 180 arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o 181fi 182 183btf_vmlinux_bin_o= 184btfids_vmlinux= 185kallsymso= 186strip_debug= 187generate_map= 188 189# Use "make UT=1" to trigger warnings on unused tracepoints 190case "${WARN_ON_UNUSED_TRACEPOINTS}" in 191*1*) 192 ${objtree}/scripts/tracepoint-update vmlinux.o 193 ;; 194esac 195 196if is_enabled CONFIG_KALLSYMS; then 197 true > .tmp_vmlinux0.syms 198 kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms 199fi 200 201if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then 202 203 # The kallsyms linking does not need debug symbols, but the BTF does. 204 if ! is_enabled CONFIG_DEBUG_INFO_BTF; then 205 strip_debug=1 206 fi 207 208 vmlinux_link .tmp_vmlinux1 209fi 210 211if is_enabled CONFIG_DEBUG_INFO_BTF; then 212 info BTF .tmp_vmlinux1 213 if ! ${CONFIG_SHELL} ${srctree}/scripts/gen-btf.sh .tmp_vmlinux1; then 214 echo >&2 "Failed to generate BTF for vmlinux" 215 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" 216 exit 1 217 fi 218 btf_vmlinux_bin_o=.tmp_vmlinux1.btf.o 219 btfids_vmlinux=.tmp_vmlinux1.BTF_ids 220fi 221 222if is_enabled CONFIG_KALLSYMS; then 223 224 # kallsyms support 225 # Generate section listing all symbols and add it into vmlinux 226 # It's a four step process: 227 # 0) Generate a dummy __kallsyms with empty symbol list. 228 # 1) Link .tmp_vmlinux1.kallsyms so it has all symbols and sections, 229 # with a dummy __kallsyms. 230 # Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with 231 # the right size 232 # 2) Link .tmp_vmlinux2.kallsyms so it now has a __kallsyms section of 233 # the right size, but due to the added section, some 234 # addresses have shifted. 235 # From here, we generate a correct .tmp_vmlinux2.kallsyms.o 236 # 3) That link may have expanded the kernel image enough that 237 # more linker branch stubs / trampolines had to be added, which 238 # introduces new names, which further expands kallsyms. Do another 239 # pass if that is the case. In theory it's possible this results 240 # in even more stubs, but unlikely. 241 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 242 # other bugs. 243 # 4) The correct ${kallsymso} is linked into the final vmlinux. 244 # 245 # a) Verify that the System.map from vmlinux matches the map from 246 # ${kallsymso}. 247 248 # The kallsyms linking does not need debug symbols included. 249 strip_debug=1 250 251 sysmap_and_kallsyms .tmp_vmlinux1 252 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 253 254 vmlinux_link .tmp_vmlinux2 255 sysmap_and_kallsyms .tmp_vmlinux2 256 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 257 258 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 259 vmlinux_link .tmp_vmlinux3 260 sysmap_and_kallsyms .tmp_vmlinux3 261 fi 262fi 263 264strip_debug= 265 266if is_enabled CONFIG_VMLINUX_MAP; then 267 generate_map=1 268fi 269 270vmlinux_link "${VMLINUX}" 271 272if is_enabled CONFIG_DEBUG_INFO_BTF; then 273 info BTFIDS ${VMLINUX} 274 ${RESOLVE_BTFIDS} --patch_btfids ${btfids_vmlinux} ${VMLINUX} 275fi 276 277mksysmap "${VMLINUX}" System.map 278 279if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then 280 info SORTTAB "${VMLINUX}" 281 if ! sorttable "${VMLINUX}"; then 282 echo >&2 Failed to sort kernel tables 283 exit 1 284 fi 285fi 286 287# step a (see comment above) 288if is_enabled CONFIG_KALLSYMS; then 289 if ! cmp -s System.map "${kallsyms_sysmap}"; then 290 echo >&2 Inconsistent kallsyms data 291 echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround' 292 exit 1 293 fi 294fi 295 296# For fixdep 297echo "${VMLINUX}: $0" > ".${VMLINUX}.d" 298