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 33LD="$1" 34KBUILD_LDFLAGS="$2" 35LDFLAGS_vmlinux="$3" 36 37# Nice output in kbuild format 38# Will be supressed by "make -s" 39info() 40{ 41 printf " %-7s %s\n" "${1}" "${2}" 42} 43 44# Generate a linker script to ensure correct ordering of initcalls. 45gen_initcalls() 46{ 47 info GEN .tmp_initcalls.lds 48 49 ${PYTHON} ${srctree}/scripts/jobserver-exec \ 50 ${PERL} ${srctree}/scripts/generate_initcall_order.pl \ 51 ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS} \ 52 > .tmp_initcalls.lds 53} 54 55# If CONFIG_LTO_CLANG is selected, collect generated symbol versions into 56# .tmp_symversions.lds 57gen_symversions() 58{ 59 info GEN .tmp_symversions.lds 60 rm -f .tmp_symversions.lds 61 62 for o in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do 63 if [ -f ${o}.symversions ]; then 64 cat ${o}.symversions >> .tmp_symversions.lds 65 fi 66 done 67} 68 69# Link of vmlinux.o used for section mismatch analysis 70# ${1} output file 71modpost_link() 72{ 73 local objects 74 local lds="" 75 76 objects="--whole-archive \ 77 ${KBUILD_VMLINUX_OBJS} \ 78 --no-whole-archive \ 79 --start-group \ 80 ${KBUILD_VMLINUX_LIBS} \ 81 --end-group" 82 83 if [ -n "${CONFIG_LTO_CLANG}" ]; then 84 gen_initcalls 85 lds="-T .tmp_initcalls.lds" 86 87 if [ -n "${CONFIG_MODVERSIONS}" ]; then 88 gen_symversions 89 lds="${lds} -T .tmp_symversions.lds" 90 fi 91 92 # This might take a while, so indicate that we're doing 93 # an LTO link 94 info LTO ${1} 95 else 96 info LD ${1} 97 fi 98 99 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${lds} ${objects} 100} 101 102objtool_link() 103{ 104 local objtoolcmd; 105 local objtoolopt; 106 107 if [ "${CONFIG_LTO_CLANG} ${CONFIG_STACK_VALIDATION}" = "y y" ]; then 108 # Don't perform vmlinux validation unless explicitly requested, 109 # but run objtool on vmlinux.o now that we have an object file. 110 if [ -n "${CONFIG_UNWINDER_ORC}" ]; then 111 objtoolcmd="orc generate" 112 fi 113 114 objtoolopt="${objtoolopt} --duplicate" 115 116 if [ -n "${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL}" ]; then 117 objtoolopt="${objtoolopt} --mcount" 118 fi 119 fi 120 121 if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then 122 objtoolopt="${objtoolopt} --noinstr" 123 if is_enabled CONFIG_CPU_UNRET_ENTRY; then 124 objtoolopt="${objtoolopt} --unret" 125 fi 126 fi 127 128 if [ -n "${objtoolopt}" ]; then 129 if [ -z "${objtoolcmd}" ]; then 130 objtoolcmd="check" 131 fi 132 objtoolopt="${objtoolopt} --vmlinux" 133 if [ -z "${CONFIG_FRAME_POINTER}" ]; then 134 objtoolopt="${objtoolopt} --no-fp" 135 fi 136 if [ -n "${CONFIG_GCOV_KERNEL}" ] || [ -n "${CONFIG_LTO_CLANG}" ]; then 137 objtoolopt="${objtoolopt} --no-unreachable" 138 fi 139 if [ -n "${CONFIG_RETPOLINE}" ]; then 140 objtoolopt="${objtoolopt} --retpoline" 141 fi 142 if [ -n "${CONFIG_X86_SMAP}" ]; then 143 objtoolopt="${objtoolopt} --uaccess" 144 fi 145 if [ -n "${CONFIG_SLS}" ]; then 146 objtoolopt="${objtoolopt} --sls" 147 fi 148 info OBJTOOL ${1} 149 tools/objtool/objtool ${objtoolcmd} ${objtoolopt} ${1} 150 fi 151} 152 153# Link of vmlinux 154# ${1} - output file 155# ${2}, ${3}, ... - optional extra .o files 156vmlinux_link() 157{ 158 local output=${1} 159 local objs 160 local libs 161 local ld 162 local ldflags 163 local ldlibs 164 165 info LD ${output} 166 167 # skip output file argument 168 shift 169 170 if [ -n "${CONFIG_LTO_CLANG}" ]; then 171 # Use vmlinux.o instead of performing the slow LTO link again. 172 objs=vmlinux.o 173 libs= 174 else 175 objs="${KBUILD_VMLINUX_OBJS}" 176 libs="${KBUILD_VMLINUX_LIBS}" 177 fi 178 179 if [ "${SRCARCH}" = "um" ]; then 180 wl=-Wl, 181 ld="${CC}" 182 ldflags="${CFLAGS_vmlinux}" 183 ldlibs="-lutil -lrt -lpthread" 184 else 185 wl= 186 ld="${LD}" 187 ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}" 188 ldlibs= 189 fi 190 191 ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}" 192 193 # The kallsyms linking does not need debug symbols included. 194 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then 195 ldflags="${ldflags} ${wl}--strip-debug" 196 fi 197 198 if [ -n "${CONFIG_VMLINUX_MAP}" ]; then 199 ldflags="${ldflags} ${wl}-Map=${output}.map" 200 fi 201 202 ${ld} ${ldflags} -o ${output} \ 203 ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \ 204 ${wl}--start-group ${libs} ${wl}--end-group \ 205 $@ ${ldlibs} 206} 207 208# generate .BTF typeinfo from DWARF debuginfo 209# ${1} - vmlinux image 210# ${2} - file to dump raw BTF data into 211gen_btf() 212{ 213 local pahole_ver 214 215 if ! [ -x "$(command -v ${PAHOLE})" ]; then 216 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available" 217 return 1 218 fi 219 220 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/') 221 if [ "${pahole_ver}" -lt "116" ]; then 222 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16" 223 return 1 224 fi 225 226 vmlinux_link ${1} 227 228 info "BTF" ${2} 229 LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1} 230 231 # Create ${2} which contains just .BTF section but no symbols. Add 232 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all 233 # deletes all symbols including __start_BTF and __stop_BTF, which will 234 # be redefined in the linker script. Add 2>/dev/null to suppress GNU 235 # objcopy warnings: "empty loadable segment detected at ..." 236 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \ 237 --strip-all ${1} ${2} 2>/dev/null 238 # Change e_type to ET_REL so that it can be used to link final vmlinux. 239 # GNU ld 2.35+ and lld do not allow an ET_EXEC input. 240 if [ -n "${CONFIG_CPU_BIG_ENDIAN}" ]; then 241 et_rel='\0\1' 242 else 243 et_rel='\1\0' 244 fi 245 printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none 246} 247 248# Create ${2} .S file with all symbols from the ${1} object file 249kallsyms() 250{ 251 local kallsymopt; 252 253 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then 254 kallsymopt="${kallsymopt} --all-symbols" 255 fi 256 257 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then 258 kallsymopt="${kallsymopt} --absolute-percpu" 259 fi 260 261 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then 262 kallsymopt="${kallsymopt} --base-relative" 263 fi 264 265 info KSYMS ${2} 266 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2} 267} 268 269# Perform one step in kallsyms generation, including temporary linking of 270# vmlinux. 271kallsyms_step() 272{ 273 kallsymso_prev=${kallsymso} 274 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1} 275 kallsymso=${kallsyms_vmlinux}.o 276 kallsyms_S=${kallsyms_vmlinux}.S 277 278 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o} 279 kallsyms ${kallsyms_vmlinux} ${kallsyms_S} 280 281 info AS ${kallsyms_S} 282 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \ 283 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \ 284 -c -o ${kallsymso} ${kallsyms_S} 285} 286 287# Create map file with all symbols from ${1} 288# See mksymap for additional details 289mksysmap() 290{ 291 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} 292} 293 294sorttable() 295{ 296 ${objtree}/scripts/sorttable ${1} 297} 298 299# Delete output files in case of error 300cleanup() 301{ 302 rm -f .btf.* 303 rm -f .tmp_System.map 304 rm -f .tmp_initcalls.lds 305 rm -f .tmp_symversions.lds 306 rm -f .tmp_vmlinux* 307 rm -f System.map 308 rm -f vmlinux 309 rm -f vmlinux.map 310 rm -f vmlinux.o 311 rm -f .vmlinux.d 312} 313 314# Use "make V=1" to debug this script 315case "${KBUILD_VERBOSE}" in 316*1*) 317 set -x 318 ;; 319esac 320 321if [ "$1" = "clean" ]; then 322 cleanup 323 exit 0 324fi 325 326# We need access to CONFIG_ symbols 327. include/config/auto.conf 328 329# Update version 330info GEN .version 331if [ -r .version ]; then 332 VERSION=$(expr 0$(cat .version) + 1) 333 echo $VERSION > .version 334else 335 rm -f .version 336 echo 1 > .version 337fi; 338 339# final build of init/ 340${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1 341 342#link vmlinux.o 343modpost_link vmlinux.o 344objtool_link vmlinux.o 345 346# modpost vmlinux.o to check for section mismatches 347${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1 348 349info MODINFO modules.builtin.modinfo 350${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo 351info GEN modules.builtin 352# The second line aids cases where multiple modules share the same object. 353tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' | 354 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin 355 356btf_vmlinux_bin_o="" 357if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then 358 btf_vmlinux_bin_o=.btf.vmlinux.bin.o 359 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then 360 echo >&2 "Failed to generate BTF for vmlinux" 361 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF" 362 exit 1 363 fi 364fi 365 366kallsymso="" 367kallsymso_prev="" 368kallsyms_vmlinux="" 369if [ -n "${CONFIG_KALLSYMS}" ]; then 370 371 # kallsyms support 372 # Generate section listing all symbols and add it into vmlinux 373 # It's a three step process: 374 # 1) Link .tmp_vmlinux1 so it has all symbols and sections, 375 # but __kallsyms is empty. 376 # Running kallsyms on that gives us .tmp_kallsyms1.o with 377 # the right size 378 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of 379 # the right size, but due to the added section, some 380 # addresses have shifted. 381 # From here, we generate a correct .tmp_kallsyms2.o 382 # 3) That link may have expanded the kernel image enough that 383 # more linker branch stubs / trampolines had to be added, which 384 # introduces new names, which further expands kallsyms. Do another 385 # pass if that is the case. In theory it's possible this results 386 # in even more stubs, but unlikely. 387 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around 388 # other bugs. 389 # 4) The correct ${kallsymso} is linked into the final vmlinux. 390 # 391 # a) Verify that the System.map from vmlinux matches the map from 392 # ${kallsymso}. 393 394 kallsyms_step 1 395 kallsyms_step 2 396 397 # step 3 398 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev}) 399 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso}) 400 401 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then 402 kallsyms_step 3 403 fi 404fi 405 406vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} 407 408# fill in BTF IDs 409if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then 410 info BTFIDS vmlinux 411 ${RESOLVE_BTFIDS} vmlinux 412fi 413 414if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then 415 info SORTTAB vmlinux 416 if ! sorttable vmlinux; then 417 echo >&2 Failed to sort kernel tables 418 exit 1 419 fi 420fi 421 422info SYSMAP System.map 423mksysmap vmlinux System.map 424 425# step a (see comment above) 426if [ -n "${CONFIG_KALLSYMS}" ]; then 427 mksysmap ${kallsyms_vmlinux} .tmp_System.map 428 429 if ! cmp -s System.map .tmp_System.map; then 430 echo >&2 Inconsistent kallsyms data 431 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround 432 exit 1 433 fi 434fi 435 436# For fixdep 437echo "vmlinux: $0" > .vmlinux.d 438