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 ${1} 116 117 # dump .BTF section into raw binary file to link with final vmlinux 118 bin_arch=$(${OBJDUMP} -f ${1} | grep architecture | \ 119 cut -d, -f1 | cut -d' ' -f2) 120 ${OBJCOPY} --dump-section .BTF=.btf.vmlinux.bin ${1} 2>/dev/null 121 ${OBJCOPY} -I binary -O ${CONFIG_OUTPUT_FORMAT} -B ${bin_arch} \ 122 --rename-section .data=.BTF .btf.vmlinux.bin ${2} 123} 124 125# Create ${2} .o file with all symbols from the ${1} object file 126kallsyms() 127{ 128 info KSYM ${2} 129 local kallsymopt; 130 131 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then 132 kallsymopt="${kallsymopt} --all-symbols" 133 fi 134 135 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then 136 kallsymopt="${kallsymopt} --absolute-percpu" 137 fi 138 139 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then 140 kallsymopt="${kallsymopt} --base-relative" 141 fi 142 143 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ 144 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}" 145 146 local afile="`basename ${2} .o`.S" 147 148 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile} 149 ${CC} ${aflags} -c -o ${2} ${afile} 150} 151 152# Create map file with all symbols from ${1} 153# See mksymap for additional details 154mksysmap() 155{ 156 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} 157} 158 159sortextable() 160{ 161 ${objtree}/scripts/sortextable ${1} 162} 163 164# Delete output files in case of error 165cleanup() 166{ 167 rm -f .btf.* 168 rm -f .tmp_System.map 169 rm -f .tmp_kallsyms* 170 rm -f .tmp_vmlinux* 171 rm -f System.map 172 rm -f vmlinux 173 rm -f vmlinux.o 174} 175 176on_exit() 177{ 178 if [ $? -ne 0 ]; then 179 cleanup 180 fi 181} 182trap on_exit EXIT 183 184on_signals() 185{ 186 exit 1 187} 188trap on_signals HUP INT QUIT TERM 189 190# 191# 192# Use "make V=1" to debug this script 193case "${KBUILD_VERBOSE}" in 194*1*) 195 set -x 196 ;; 197esac 198 199if [ "$1" = "clean" ]; then 200 cleanup 201 exit 0 202fi 203 204# We need access to CONFIG_ symbols 205. include/config/auto.conf 206 207# Update version 208info GEN .version 209if [ -r .version ]; then 210 VERSION=$(expr 0$(cat .version) + 1) 211 echo $VERSION > .version 212else 213 rm -f .version 214 echo 1 > .version 215fi; 216 217# final build of init/ 218${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init 219 220#link vmlinux.o 221info LD vmlinux.o 222modpost_link vmlinux.o 223 224# modpost vmlinux.o to check for section mismatches 225${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1 226 227info MODINFO modules.builtin.modinfo 228${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo 229 230btf_vmlinux_bin_o="" 231if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then 232 if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then 233 btf_vmlinux_bin_o=.btf.vmlinux.bin.o 234 fi 235fi 236 237kallsymso="" 238kallsyms_vmlinux="" 239if [ -n "${CONFIG_KALLSYMS}" ]; then 240 241 # kallsyms support 242 # Generate section listing all symbols and add it into vmlinux 243 # It's a three step process: 244 # 1) Link .tmp_vmlinux1 so it has all symbols and sections, 245 # but __kallsyms is empty. 246 # Running kallsyms on that gives us .tmp_kallsyms1.o with 247 # the right size 248 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of 249 # the right size, but due to the added section, some 250 # addresses have shifted. 251 # From here, we generate a correct .tmp_kallsyms2.o 252 # 3) That link may have expanded the kernel image enough that 253 # more linker branch stubs / trampolines had to be added, which 254 # introduces new names, which further expands kallsyms. Do another 255 # pass if that is the case. In theory it's possible this results 256 # in even more stubs, but unlikely. 257 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 258 # other bugs. 259 # 4) The correct ${kallsymso} is linked into the final vmlinux. 260 # 261 # a) Verify that the System.map from vmlinux matches the map from 262 # ${kallsymso}. 263 264 kallsymso=.tmp_kallsyms2.o 265 kallsyms_vmlinux=.tmp_vmlinux2 266 267 # step 1 268 vmlinux_link .tmp_vmlinux1 ${btf_vmlinux_bin_o} 269 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o 270 271 # step 2 272 vmlinux_link .tmp_vmlinux2 .tmp_kallsyms1.o ${btf_vmlinux_bin_o} 273 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o 274 275 # step 3 276 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o) 277 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o) 278 279 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 280 kallsymso=.tmp_kallsyms3.o 281 kallsyms_vmlinux=.tmp_vmlinux3 282 283 vmlinux_link .tmp_vmlinux3 .tmp_kallsyms2.o ${btf_vmlinux_bin_o} 284 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o 285 fi 286fi 287 288info LD vmlinux 289vmlinux_link vmlinux "${kallsymso}" "${btf_vmlinux_bin_o}" 290 291if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then 292 info SORTEX vmlinux 293 sortextable vmlinux 294fi 295 296info SYSMAP System.map 297mksysmap vmlinux System.map 298 299# step a (see comment above) 300if [ -n "${CONFIG_KALLSYMS}" ]; then 301 mksysmap ${kallsyms_vmlinux} .tmp_System.map 302 303 if ! cmp -s System.map .tmp_System.map; then 304 echo >&2 Inconsistent kallsyms data 305 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround 306 exit 1 307 fi 308fi 309