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} - optional extra .o files 60# ${2} - output file 61vmlinux_link() 62{ 63 local lds="${objtree}/${KBUILD_LDS}" 64 local objects 65 66 if [ "${SRCARCH}" != "um" ]; then 67 objects="--whole-archive \ 68 ${KBUILD_VMLINUX_OBJS} \ 69 --no-whole-archive \ 70 --start-group \ 71 ${KBUILD_VMLINUX_LIBS} \ 72 --end-group \ 73 ${1}" 74 75 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \ 76 -T ${lds} ${objects} 77 else 78 objects="-Wl,--whole-archive \ 79 ${KBUILD_VMLINUX_OBJS} \ 80 -Wl,--no-whole-archive \ 81 -Wl,--start-group \ 82 ${KBUILD_VMLINUX_LIBS} \ 83 -Wl,--end-group \ 84 ${1}" 85 86 ${CC} ${CFLAGS_vmlinux} -o ${2} \ 87 -Wl,-T,${lds} \ 88 ${objects} \ 89 -lutil -lrt -lpthread 90 rm -f linux 91 fi 92} 93 94# generate .BTF typeinfo from DWARF debuginfo 95gen_btf() 96{ 97 local pahole_ver; 98 99 if ! [ -x "$(command -v ${PAHOLE})" ]; then 100 info "BTF" "${1}: pahole (${PAHOLE}) is not available" 101 return 0 102 fi 103 104 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/') 105 if [ "${pahole_ver}" -lt "113" ]; then 106 info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13" 107 return 0 108 fi 109 110 info "BTF" ${1} 111 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} 112} 113 114# Create ${2} .o file with all symbols from the ${1} object file 115kallsyms() 116{ 117 info KSYM ${2} 118 local kallsymopt; 119 120 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then 121 kallsymopt="${kallsymopt} --all-symbols" 122 fi 123 124 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then 125 kallsymopt="${kallsymopt} --absolute-percpu" 126 fi 127 128 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then 129 kallsymopt="${kallsymopt} --base-relative" 130 fi 131 132 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ 133 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}" 134 135 local afile="`basename ${2} .o`.S" 136 137 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile} 138 ${CC} ${aflags} -c -o ${2} ${afile} 139} 140 141# Create map file with all symbols from ${1} 142# See mksymap for additional details 143mksysmap() 144{ 145 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} 146} 147 148sortextable() 149{ 150 ${objtree}/scripts/sortextable ${1} 151} 152 153# Delete output files in case of error 154cleanup() 155{ 156 rm -f .tmp_System.map 157 rm -f .tmp_kallsyms* 158 rm -f .tmp_vmlinux* 159 rm -f System.map 160 rm -f vmlinux 161 rm -f vmlinux.o 162} 163 164on_exit() 165{ 166 if [ $? -ne 0 ]; then 167 cleanup 168 fi 169} 170trap on_exit EXIT 171 172on_signals() 173{ 174 exit 1 175} 176trap on_signals HUP INT QUIT TERM 177 178# 179# 180# Use "make V=1" to debug this script 181case "${KBUILD_VERBOSE}" in 182*1*) 183 set -x 184 ;; 185esac 186 187if [ "$1" = "clean" ]; then 188 cleanup 189 exit 0 190fi 191 192# We need access to CONFIG_ symbols 193. include/config/auto.conf 194 195# Update version 196info GEN .version 197if [ -r .version ]; then 198 VERSION=$(expr 0$(cat .version) + 1) 199 echo $VERSION > .version 200else 201 rm -f .version 202 echo 1 > .version 203fi; 204 205# final build of init/ 206${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init 207 208#link vmlinux.o 209info LD vmlinux.o 210modpost_link vmlinux.o 211 212# modpost vmlinux.o to check for section mismatches 213${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o 214 215info MODINFO modules.builtin.modinfo 216${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo 217 218kallsymso="" 219kallsyms_vmlinux="" 220if [ -n "${CONFIG_KALLSYMS}" ]; then 221 222 # kallsyms support 223 # Generate section listing all symbols and add it into vmlinux 224 # It's a three step process: 225 # 1) Link .tmp_vmlinux1 so it has all symbols and sections, 226 # but __kallsyms is empty. 227 # Running kallsyms on that gives us .tmp_kallsyms1.o with 228 # the right size 229 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of 230 # the right size, but due to the added section, some 231 # addresses have shifted. 232 # From here, we generate a correct .tmp_kallsyms2.o 233 # 3) That link may have expanded the kernel image enough that 234 # more linker branch stubs / trampolines had to be added, which 235 # introduces new names, which further expands kallsyms. Do another 236 # pass if that is the case. In theory it's possible this results 237 # in even more stubs, but unlikely. 238 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 239 # other bugs. 240 # 4) The correct ${kallsymso} is linked into the final vmlinux. 241 # 242 # a) Verify that the System.map from vmlinux matches the map from 243 # ${kallsymso}. 244 245 kallsymso=.tmp_kallsyms2.o 246 kallsyms_vmlinux=.tmp_vmlinux2 247 248 # step 1 249 vmlinux_link "" .tmp_vmlinux1 250 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o 251 252 # step 2 253 vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2 254 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o 255 256 # step 3 257 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o) 258 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o) 259 260 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 261 kallsymso=.tmp_kallsyms3.o 262 kallsyms_vmlinux=.tmp_vmlinux3 263 264 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3 265 266 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o 267 fi 268fi 269 270info LD vmlinux 271vmlinux_link "${kallsymso}" vmlinux 272 273if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then 274 gen_btf vmlinux 275fi 276 277if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then 278 info SORTEX vmlinux 279 sortextable vmlinux 280fi 281 282info SYSMAP System.map 283mksysmap vmlinux System.map 284 285# step a (see comment above) 286if [ -n "${CONFIG_KALLSYMS}" ]; then 287 mksysmap ${kallsyms_vmlinux} .tmp_System.map 288 289 if ! cmp -s System.map .tmp_System.map; 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