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