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# ${@:2} - optional extra .o files 61vmlinux_link() 62{ 63 local lds="${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 ${@:2}" 74 75 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${1} \ 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 ${@:2}" 85 86 ${CC} ${CFLAGS_vmlinux} -o ${1} \ 87 -Wl,-T,${lds} \ 88 ${objects} \ 89 -lutil -lrt -lpthread 90 rm -f linux 91 fi 92} 93 94# generate .BTF typeinfo from DWARF debuginfo 95# ${1} - vmlinux image 96# ${2} - file to dump raw BTF data into 97gen_btf() 98{ 99 local pahole_ver 100 local bin_arch 101 102 if ! [ -x "$(command -v ${PAHOLE})" ]; then 103 info "BTF" "${1}: pahole (${PAHOLE}) is not available" 104 return 1 105 fi 106 107 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/') 108 if [ "${pahole_ver}" -lt "113" ]; then 109 info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13" 110 return 1 111 fi 112 113 info "BTF" ${2} 114 vmlinux_link ${1} 115 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} 116 117 # dump .BTF section into raw binary file to link with final vmlinux 118 bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \ 119 cut -d, -f1 | cut -d' ' -f2) 120 bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \ 121 awk '{print $4}') 122 ${OBJCOPY} --dump-section .BTF=.btf.vmlinux.bin ${1} 2>/dev/null 123 ${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \ 124 --rename-section .data=.BTF .btf.vmlinux.bin ${2} 125} 126 127# Create ${2} .o file with all symbols from the ${1} object file 128kallsyms() 129{ 130 info KSYM ${2} 131 local kallsymopt; 132 133 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then 134 kallsymopt="${kallsymopt} --all-symbols" 135 fi 136 137 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then 138 kallsymopt="${kallsymopt} --absolute-percpu" 139 fi 140 141 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then 142 kallsymopt="${kallsymopt} --base-relative" 143 fi 144 145 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ 146 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}" 147 148 local afile="`basename ${2} .o`.S" 149 150 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile} 151 ${CC} ${aflags} -c -o ${2} ${afile} 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 .btf.* 170 rm -f .tmp_System.map 171 rm -f .tmp_kallsyms* 172 rm -f .tmp_vmlinux* 173 rm -f System.map 174 rm -f vmlinux 175 rm -f vmlinux.o 176} 177 178on_exit() 179{ 180 if [ $? -ne 0 ]; then 181 cleanup 182 fi 183} 184trap on_exit EXIT 185 186on_signals() 187{ 188 exit 1 189} 190trap on_signals HUP INT QUIT TERM 191 192# 193# 194# Use "make V=1" to debug this script 195case "${KBUILD_VERBOSE}" in 196*1*) 197 set -x 198 ;; 199esac 200 201if [ "$1" = "clean" ]; then 202 cleanup 203 exit 0 204fi 205 206# We need access to CONFIG_ symbols 207. include/config/auto.conf 208 209# Update version 210info GEN .version 211if [ -r .version ]; then 212 VERSION=$(expr 0$(cat .version) + 1) 213 echo $VERSION > .version 214else 215 rm -f .version 216 echo 1 > .version 217fi; 218 219# final build of init/ 220${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init 221 222#link vmlinux.o 223info LD vmlinux.o 224modpost_link vmlinux.o 225 226# modpost vmlinux.o to check for section mismatches 227${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1 228 229info MODINFO modules.builtin.modinfo 230${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo 231 232btf_vmlinux_bin_o="" 233if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then 234 if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then 235 btf_vmlinux_bin_o=.btf.vmlinux.bin.o 236 fi 237fi 238 239kallsymso="" 240kallsyms_vmlinux="" 241if [ -n "${CONFIG_KALLSYMS}" ]; then 242 243 # kallsyms support 244 # Generate section listing all symbols and add it into vmlinux 245 # It's a three step process: 246 # 1) Link .tmp_vmlinux1 so it has all symbols and sections, 247 # but __kallsyms is empty. 248 # Running kallsyms on that gives us .tmp_kallsyms1.o with 249 # the right size 250 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of 251 # the right size, but due to the added section, some 252 # addresses have shifted. 253 # From here, we generate a correct .tmp_kallsyms2.o 254 # 3) That link may have expanded the kernel image enough that 255 # more linker branch stubs / trampolines had to be added, which 256 # introduces new names, which further expands kallsyms. Do another 257 # pass if that is the case. In theory it's possible this results 258 # in even more stubs, but unlikely. 259 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 260 # other bugs. 261 # 4) The correct ${kallsymso} is linked into the final vmlinux. 262 # 263 # a) Verify that the System.map from vmlinux matches the map from 264 # ${kallsymso}. 265 266 kallsymso=.tmp_kallsyms2.o 267 kallsyms_vmlinux=.tmp_vmlinux2 268 269 # step 1 270 vmlinux_link .tmp_vmlinux1 ${btf_vmlinux_bin_o} 271 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o 272 273 # step 2 274 vmlinux_link .tmp_vmlinux2 .tmp_kallsyms1.o ${btf_vmlinux_bin_o} 275 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o 276 277 # step 3 278 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o) 279 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o) 280 281 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 282 kallsymso=.tmp_kallsyms3.o 283 kallsyms_vmlinux=.tmp_vmlinux3 284 285 vmlinux_link .tmp_vmlinux3 .tmp_kallsyms2.o ${btf_vmlinux_bin_o} 286 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o 287 fi 288fi 289 290info LD vmlinux 291vmlinux_link vmlinux "${kallsymso}" "${btf_vmlinux_bin_o}" 292 293if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then 294 info SORTEX vmlinux 295 sortextable vmlinux 296fi 297 298info SYSMAP System.map 299mksysmap vmlinux System.map 300 301# step a (see comment above) 302if [ -n "${CONFIG_KALLSYMS}" ]; then 303 mksysmap ${kallsyms_vmlinux} .tmp_System.map 304 305 if ! cmp -s System.map .tmp_System.map; then 306 echo >&2 Inconsistent kallsyms data 307 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround 308 exit 1 309 fi 310fi 311