1#!/bin/sh 2# SPDX-License-Identifier: GPL-2.0 3# 4# link vmlinux 5# 6# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_OBJS) and 7# $(KBUILD_VMLINUX_LIBS). Most are built-in.a files from top-level directories 8# in the kernel tree, others are specified in arch/$(ARCH)/Makefile. 9# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally 10# (not within --whole-archive), and do not require symbol indexes added. 11# 12# vmlinux 13# ^ 14# | 15# +--< $(KBUILD_VMLINUX_OBJS) 16# | +--< init/built-in.a drivers/built-in.a mm/built-in.a + more 17# | 18# +--< $(KBUILD_VMLINUX_LIBS) 19# | +--< lib/lib.a + more 20# | 21# +-< ${kallsymso} (see description in KALLSYMS section) 22# 23# vmlinux version (uname -v) cannot be updated during normal 24# descending-into-subdirs phase since we do not yet know if we need to 25# update vmlinux. 26# Therefore this step is delayed until just before final link of vmlinux. 27# 28# System.map is generated to document addresses of all kernel symbols 29 30# Error out on error 31set -e 32 33# Nice output in kbuild format 34# Will be supressed by "make -s" 35info() 36{ 37 if [ "${quiet}" != "silent_" ]; then 38 printf " %-7s %s\n" "${1}" "${2}" 39 fi 40} 41 42# Link of vmlinux.o used for section mismatch analysis 43# ${1} output file 44modpost_link() 45{ 46 local objects 47 48 objects="--whole-archive \ 49 ${KBUILD_VMLINUX_OBJS} \ 50 --no-whole-archive \ 51 --start-group \ 52 ${KBUILD_VMLINUX_LIBS} \ 53 --end-group" 54 55 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects} 56} 57 58# Link of vmlinux 59# ${1} - output file 60# ${2}, ${3}, ... - optional extra .o files 61vmlinux_link() 62{ 63 local lds="${objtree}/${KBUILD_LDS}" 64 local output=${1} 65 local objects 66 67 # skip output file argument 68 shift 69 70 if [ "${SRCARCH}" != "um" ]; then 71 objects="--whole-archive \ 72 ${KBUILD_VMLINUX_OBJS} \ 73 --no-whole-archive \ 74 --start-group \ 75 ${KBUILD_VMLINUX_LIBS} \ 76 --end-group \ 77 ${@}" 78 79 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \ 80 -o ${output} \ 81 -T ${lds} ${objects} 82 else 83 objects="-Wl,--whole-archive \ 84 ${KBUILD_VMLINUX_OBJS} \ 85 -Wl,--no-whole-archive \ 86 -Wl,--start-group \ 87 ${KBUILD_VMLINUX_LIBS} \ 88 -Wl,--end-group \ 89 ${@}" 90 91 ${CC} ${CFLAGS_vmlinux} \ 92 -o ${output} \ 93 -Wl,-T,${lds} \ 94 ${objects} \ 95 -lutil -lrt -lpthread 96 rm -f linux 97 fi 98} 99 100# generate .BTF typeinfo from DWARF debuginfo 101# ${1} - vmlinux image 102# ${2} - file to dump raw BTF data into 103gen_btf() 104{ 105 local pahole_ver 106 local bin_arch 107 108 if ! [ -x "$(command -v ${PAHOLE})" ]; then 109 info "BTF" "${1}: pahole (${PAHOLE}) is not available" 110 return 1 111 fi 112 113 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/') 114 if [ "${pahole_ver}" -lt "113" ]; then 115 info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13" 116 return 1 117 fi 118 119 info "BTF" ${2} 120 vmlinux_link ${1} 121 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} 122 123 # dump .BTF section into raw binary file to link with final vmlinux 124 bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \ 125 cut -d, -f1 | cut -d' ' -f2) 126 bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \ 127 awk '{print $4}') 128 ${OBJCOPY} --dump-section .BTF=.btf.vmlinux.bin ${1} 2>/dev/null 129 ${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \ 130 --rename-section .data=.BTF .btf.vmlinux.bin ${2} 131} 132 133# Create ${2} .o file with all symbols from the ${1} object file 134kallsyms() 135{ 136 info KSYM ${2} 137 local kallsymopt; 138 139 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then 140 kallsymopt="${kallsymopt} --all-symbols" 141 fi 142 143 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then 144 kallsymopt="${kallsymopt} --absolute-percpu" 145 fi 146 147 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then 148 kallsymopt="${kallsymopt} --base-relative" 149 fi 150 151 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ 152 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}" 153 154 local afile="`basename ${2} .o`.S" 155 156 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile} 157 ${CC} ${aflags} -c -o ${2} ${afile} 158} 159 160# Create map file with all symbols from ${1} 161# See mksymap for additional details 162mksysmap() 163{ 164 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} 165} 166 167sortextable() 168{ 169 ${objtree}/scripts/sortextable ${1} 170} 171 172# Delete output files in case of error 173cleanup() 174{ 175 rm -f .btf.* 176 rm -f .tmp_System.map 177 rm -f .tmp_kallsyms* 178 rm -f .tmp_vmlinux* 179 rm -f System.map 180 rm -f vmlinux 181 rm -f vmlinux.o 182} 183 184on_exit() 185{ 186 if [ $? -ne 0 ]; then 187 cleanup 188 fi 189} 190trap on_exit EXIT 191 192on_signals() 193{ 194 exit 1 195} 196trap on_signals HUP INT QUIT TERM 197 198# 199# 200# Use "make V=1" to debug this script 201case "${KBUILD_VERBOSE}" in 202*1*) 203 set -x 204 ;; 205esac 206 207if [ "$1" = "clean" ]; then 208 cleanup 209 exit 0 210fi 211 212# We need access to CONFIG_ symbols 213. include/config/auto.conf 214 215# Update version 216info GEN .version 217if [ -r .version ]; then 218 VERSION=$(expr 0$(cat .version) + 1) 219 echo $VERSION > .version 220else 221 rm -f .version 222 echo 1 > .version 223fi; 224 225# final build of init/ 226${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init 227 228#link vmlinux.o 229info LD vmlinux.o 230modpost_link vmlinux.o 231 232# modpost vmlinux.o to check for section mismatches 233${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1 234 235info MODINFO modules.builtin.modinfo 236${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo 237 238btf_vmlinux_bin_o="" 239if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then 240 if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then 241 btf_vmlinux_bin_o=.btf.vmlinux.bin.o 242 fi 243fi 244 245kallsymso="" 246kallsyms_vmlinux="" 247if [ -n "${CONFIG_KALLSYMS}" ]; then 248 249 # kallsyms support 250 # Generate section listing all symbols and add it into vmlinux 251 # It's a three step process: 252 # 1) Link .tmp_vmlinux1 so it has all symbols and sections, 253 # but __kallsyms is empty. 254 # Running kallsyms on that gives us .tmp_kallsyms1.o with 255 # the right size 256 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of 257 # the right size, but due to the added section, some 258 # addresses have shifted. 259 # From here, we generate a correct .tmp_kallsyms2.o 260 # 3) That link may have expanded the kernel image enough that 261 # more linker branch stubs / trampolines had to be added, which 262 # introduces new names, which further expands kallsyms. Do another 263 # pass if that is the case. In theory it's possible this results 264 # in even more stubs, but unlikely. 265 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 266 # other bugs. 267 # 4) The correct ${kallsymso} is linked into the final vmlinux. 268 # 269 # a) Verify that the System.map from vmlinux matches the map from 270 # ${kallsymso}. 271 272 kallsymso=.tmp_kallsyms2.o 273 kallsyms_vmlinux=.tmp_vmlinux2 274 275 # step 1 276 vmlinux_link .tmp_vmlinux1 ${btf_vmlinux_bin_o} 277 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o 278 279 # step 2 280 vmlinux_link .tmp_vmlinux2 .tmp_kallsyms1.o ${btf_vmlinux_bin_o} 281 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o 282 283 # step 3 284 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o) 285 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o) 286 287 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 288 kallsymso=.tmp_kallsyms3.o 289 kallsyms_vmlinux=.tmp_vmlinux3 290 291 vmlinux_link .tmp_vmlinux3 .tmp_kallsyms2.o ${btf_vmlinux_bin_o} 292 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o 293 fi 294fi 295 296info LD vmlinux 297vmlinux_link vmlinux "${kallsymso}" "${btf_vmlinux_bin_o}" 298 299if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then 300 info SORTEX vmlinux 301 sortextable vmlinux 302fi 303 304info SYSMAP System.map 305mksysmap vmlinux System.map 306 307# step a (see comment above) 308if [ -n "${CONFIG_KALLSYMS}" ]; then 309 mksysmap ${kallsyms_vmlinux} .tmp_System.map 310 311 if ! cmp -s System.map .tmp_System.map; then 312 echo >&2 Inconsistent kallsyms data 313 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround 314 exit 1 315 fi 316fi 317