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 local strip_debug 67 68 info LD ${output} 69 70 # skip output file argument 71 shift 72 73 # The kallsyms linking does not need debug symbols included. 74 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then 75 strip_debug=-Wl,--strip-debug 76 fi 77 78 if [ "${SRCARCH}" != "um" ]; then 79 objects="--whole-archive \ 80 ${KBUILD_VMLINUX_OBJS} \ 81 --no-whole-archive \ 82 --start-group \ 83 ${KBUILD_VMLINUX_LIBS} \ 84 --end-group \ 85 ${@}" 86 87 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \ 88 ${strip_debug#-Wl,} \ 89 -o ${output} \ 90 -T ${lds} ${objects} 91 else 92 objects="-Wl,--whole-archive \ 93 ${KBUILD_VMLINUX_OBJS} \ 94 -Wl,--no-whole-archive \ 95 -Wl,--start-group \ 96 ${KBUILD_VMLINUX_LIBS} \ 97 -Wl,--end-group \ 98 ${@}" 99 100 ${CC} ${CFLAGS_vmlinux} \ 101 ${strip_debug} \ 102 -o ${output} \ 103 -Wl,-T,${lds} \ 104 ${objects} \ 105 -lutil -lrt -lpthread 106 rm -f linux 107 fi 108} 109 110# generate .BTF typeinfo from DWARF debuginfo 111# ${1} - vmlinux image 112# ${2} - file to dump raw BTF data into 113gen_btf() 114{ 115 local pahole_ver 116 local bin_arch 117 local bin_format 118 local bin_file 119 120 if ! [ -x "$(command -v ${PAHOLE})" ]; then 121 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" 122 return 1 123 fi 124 125 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/') 126 if [ "${pahole_ver}" -lt "113" ]; then 127 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13" 128 return 1 129 fi 130 131 vmlinux_link ${1} 132 133 info "BTF" ${2} 134 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} 135 136 # dump .BTF section into raw binary file to link with final vmlinux 137 bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \ 138 cut -d, -f1 | cut -d' ' -f2) 139 bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \ 140 awk '{print $4}') 141 bin_file=.btf.vmlinux.bin 142 ${OBJCOPY} --change-section-address .BTF=0 \ 143 --set-section-flags .BTF=alloc -O binary \ 144 --only-section=.BTF ${1} $bin_file 145 ${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \ 146 --rename-section .data=.BTF $bin_file ${2} 147} 148 149# Create ${2} .o file with all symbols from the ${1} object file 150kallsyms() 151{ 152 info KSYM ${2} 153 local kallsymopt; 154 155 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then 156 kallsymopt="${kallsymopt} --all-symbols" 157 fi 158 159 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then 160 kallsymopt="${kallsymopt} --absolute-percpu" 161 fi 162 163 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then 164 kallsymopt="${kallsymopt} --base-relative" 165 fi 166 167 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ 168 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}" 169 170 local afile="`basename ${2} .o`.S" 171 172 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile} 173 ${CC} ${aflags} -c -o ${2} ${afile} 174} 175 176# Perform one step in kallsyms generation, including temporary linking of 177# vmlinux. 178kallsyms_step() 179{ 180 kallsymso_prev=${kallsymso} 181 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1} 182 kallsymso=${kallsyms_vmlinux}.o 183 184 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o} 185 kallsyms ${kallsyms_vmlinux} ${kallsymso} 186} 187 188# Create map file with all symbols from ${1} 189# See mksymap for additional details 190mksysmap() 191{ 192 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} 193} 194 195sorttable() 196{ 197 ${objtree}/scripts/sorttable ${1} 198} 199 200# Delete output files in case of error 201cleanup() 202{ 203 rm -f .btf.* 204 rm -f .tmp_System.map 205 rm -f .tmp_vmlinux* 206 rm -f System.map 207 rm -f vmlinux 208 rm -f vmlinux.o 209} 210 211on_exit() 212{ 213 if [ $? -ne 0 ]; then 214 cleanup 215 fi 216} 217trap on_exit EXIT 218 219on_signals() 220{ 221 exit 1 222} 223trap on_signals HUP INT QUIT TERM 224 225# 226# 227# Use "make V=1" to debug this script 228case "${KBUILD_VERBOSE}" in 229*1*) 230 set -x 231 ;; 232esac 233 234if [ "$1" = "clean" ]; then 235 cleanup 236 exit 0 237fi 238 239# We need access to CONFIG_ symbols 240. include/config/auto.conf 241 242# Update version 243info GEN .version 244if [ -r .version ]; then 245 VERSION=$(expr 0$(cat .version) + 1) 246 echo $VERSION > .version 247else 248 rm -f .version 249 echo 1 > .version 250fi; 251 252# final build of init/ 253${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1 254 255#link vmlinux.o 256info LD vmlinux.o 257modpost_link vmlinux.o 258 259# modpost vmlinux.o to check for section mismatches 260${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1 261 262info MODINFO modules.builtin.modinfo 263${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo 264info GEN modules.builtin 265# The second line aids cases where multiple modules share the same object. 266tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' | 267 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin 268 269btf_vmlinux_bin_o="" 270if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then 271 btf_vmlinux_bin_o=.btf.vmlinux.bin.o 272 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then 273 echo >&2 "Failed to generate BTF for vmlinux" 274 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" 275 exit 1 276 fi 277fi 278 279kallsymso="" 280kallsymso_prev="" 281kallsyms_vmlinux="" 282if [ -n "${CONFIG_KALLSYMS}" ]; then 283 284 # kallsyms support 285 # Generate section listing all symbols and add it into vmlinux 286 # It's a three step process: 287 # 1) Link .tmp_vmlinux1 so it has all symbols and sections, 288 # but __kallsyms is empty. 289 # Running kallsyms on that gives us .tmp_kallsyms1.o with 290 # the right size 291 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of 292 # the right size, but due to the added section, some 293 # addresses have shifted. 294 # From here, we generate a correct .tmp_kallsyms2.o 295 # 3) That link may have expanded the kernel image enough that 296 # more linker branch stubs / trampolines had to be added, which 297 # introduces new names, which further expands kallsyms. Do another 298 # pass if that is the case. In theory it's possible this results 299 # in even more stubs, but unlikely. 300 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 301 # other bugs. 302 # 4) The correct ${kallsymso} is linked into the final vmlinux. 303 # 304 # a) Verify that the System.map from vmlinux matches the map from 305 # ${kallsymso}. 306 307 kallsyms_step 1 308 kallsyms_step 2 309 310 # step 3 311 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev}) 312 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 313 314 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 315 kallsyms_step 3 316 fi 317fi 318 319vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} 320 321if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then 322 info SORTTAB vmlinux 323 if ! sorttable vmlinux; then 324 echo >&2 Failed to sort kernel tables 325 exit 1 326 fi 327fi 328 329info SYSMAP System.map 330mksysmap vmlinux System.map 331 332# step a (see comment above) 333if [ -n "${CONFIG_KALLSYMS}" ]; then 334 mksysmap ${kallsyms_vmlinux} .tmp_System.map 335 336 if ! cmp -s System.map .tmp_System.map; then 337 echo >&2 Inconsistent kallsyms data 338 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround 339 exit 1 340 fi 341fi 342