2 # SPDX-License-Identifier: GPL-2.0
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.
15 # +--< $(KBUILD_VMLINUX_OBJS)
16 # | +--< init/built-in.a drivers/built-in.a mm/built-in.a + more
18 # +--< $(KBUILD_VMLINUX_LIBS)
19 # | +--< lib/lib.a + more
21 # +-< ${kallsymso} (see description in KALLSYMS section)
23 # vmlinux version (uname -v) cannot be updated during normal
24 # descending-into-subdirs phase since we do not yet know if we need to
26 # Therefore this step is delayed until just before final link of vmlinux.
28 # System.map is generated to document addresses of all kernel symbols
37 # Nice output in kbuild format
38 # Will be supressed by "make -s"
41 if [ "${quiet}" != "silent_" ]; then
42 printf " %-7s %s\n" "${1}" "${2}"
46 # Generate a linker script to ensure correct ordering of initcalls.
49 info GEN .tmp_initcalls.lds
51 ${PYTHON} ${srctree}/scripts
/jobserver-exec \
52 ${PERL} ${srctree}/scripts
/generate_initcall_order.pl \
53 ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS} \
57 # If CONFIG_LTO_CLANG is selected, collect generated symbol versions into
58 # .tmp_symversions.lds
61 info GEN .tmp_symversions.lds
62 rm -f .tmp_symversions.lds
64 for o
in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do
65 if [ -f ${o}.symversions
]; then
66 cat ${o}.symversions
>> .tmp_symversions.lds
71 # Link of vmlinux.o used for section mismatch analysis
78 objects
="--whole-archive \
79 ${KBUILD_VMLINUX_OBJS} \
82 ${KBUILD_VMLINUX_LIBS} \
85 if [ -n "${CONFIG_LTO_CLANG}" ]; then
87 lds
="-T .tmp_initcalls.lds"
89 if [ -n "${CONFIG_MODVERSIONS}" ]; then
91 lds
="${lds} -T .tmp_symversions.lds"
94 # This might take a while, so indicate that we're doing
101 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${lds} ${objects}
109 if [ "${CONFIG_LTO_CLANG} ${CONFIG_STACK_VALIDATION}" = "y y" ]; then
110 # Don't perform vmlinux validation unless explicitly requested,
111 # but run objtool on vmlinux.o now that we have an object file.
112 if [ -n "${CONFIG_UNWINDER_ORC}" ]; then
113 objtoolcmd
="orc generate"
116 objtoolopt
="${objtoolopt} --duplicate"
118 if [ -n "${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL}" ]; then
119 objtoolopt
="${objtoolopt} --mcount"
123 if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
124 objtoolopt
="${objtoolopt} --noinstr"
127 if [ -n "${objtoolopt}" ]; then
128 if [ -z "${objtoolcmd}" ]; then
131 objtoolopt
="${objtoolopt} --vmlinux"
132 if [ -z "${CONFIG_FRAME_POINTER}" ]; then
133 objtoolopt
="${objtoolopt} --no-fp"
135 if [ -n "${CONFIG_GCOV_KERNEL}" ] ||
[ -n "${CONFIG_LTO_CLANG}" ]; then
136 objtoolopt
="${objtoolopt} --no-unreachable"
138 if [ -n "${CONFIG_RETPOLINE}" ]; then
139 objtoolopt
="${objtoolopt} --retpoline"
141 if [ -n "${CONFIG_X86_SMAP}" ]; then
142 objtoolopt
="${objtoolopt} --uaccess"
145 tools
/objtool
/objtool
${objtoolcmd} ${objtoolopt} ${1}
151 # ${2}, ${3}, ... - optional extra .o files
154 local lds
="${objtree}/${KBUILD_LDS}"
161 # skip output file argument
164 # The kallsyms linking does not need debug symbols included.
165 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
166 strip_debug
=-Wl,--strip-debug
169 if [ "${SRCARCH}" != "um" ]; then
170 if [ -n "${CONFIG_LTO_CLANG}" ]; then
171 # Use vmlinux.o instead of performing the slow LTO
173 objects
="--whole-archive \
178 objects
="--whole-archive \
179 ${KBUILD_VMLINUX_OBJS} \
182 ${KBUILD_VMLINUX_LIBS} \
187 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
188 ${strip_debug#-Wl,} \
192 objects
="-Wl,--whole-archive \
193 ${KBUILD_VMLINUX_OBJS} \
194 -Wl,--no-whole-archive \
196 ${KBUILD_VMLINUX_LIBS} \
200 ${CC} ${CFLAGS_vmlinux} \
205 -lutil -lrt -lpthread
210 # generate .BTF typeinfo from DWARF debuginfo
211 # ${1} - vmlinux image
212 # ${2} - file to dump raw BTF data into
217 if ! [ -x "$(command -v ${PAHOLE})" ]; then
218 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
222 pahole_ver
=$
(${PAHOLE} --version |
sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
223 if [ "${pahole_ver}" -lt "116" ]; then
224 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
231 LLVM_OBJCOPY
=${OBJCOPY} ${PAHOLE} -J ${1}
233 # Create ${2} which contains just .BTF section but no symbols. Add
234 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
235 # deletes all symbols including __start_BTF and __stop_BTF, which will
236 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
237 # objcopy warnings: "empty loadable segment detected at ..."
238 ${OBJCOPY} --only-section=.BTF
--set-section-flags .BTF
=alloc
,readonly \
239 --strip-all ${1} ${2} 2>/dev
/null
240 # Change e_type to ET_REL so that it can be used to link final vmlinux.
241 # Unlike GNU ld, lld does not allow an ET_EXEC input.
242 printf '\1' |
dd of
=${2} conv
=notrunc bs
=1 seek
=16 status
=none
245 # Create ${2} .S file with all symbols from the ${1} object file
250 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
251 kallsymopt
="${kallsymopt} --all-symbols"
254 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
255 kallsymopt
="${kallsymopt} --absolute-percpu"
258 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
259 kallsymopt
="${kallsymopt} --base-relative"
263 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2}
266 # Perform one step in kallsyms generation, including temporary linking of
270 kallsymso_prev
=${kallsymso}
271 kallsyms_vmlinux
=.tmp_vmlinux.kallsyms
${1}
272 kallsymso
=${kallsyms_vmlinux}.o
273 kallsyms_S
=${kallsyms_vmlinux}.S
275 vmlinux_link
${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
276 kallsyms
${kallsyms_vmlinux} ${kallsyms_S}
278 info AS
${kallsyms_S}
279 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
280 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
281 -c -o ${kallsymso} ${kallsyms_S}
284 # Create map file with all symbols from ${1}
285 # See mksymap for additional details
288 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
293 ${objtree}/scripts
/sorttable
${1}
296 # Delete output files in case of error
300 rm -f .tmp_System.map
301 rm -f .tmp_initcalls.lds
302 rm -f .tmp_symversions.lds
311 if [ $?
-ne 0 ]; then
321 trap on_signals HUP INT QUIT TERM
323 # Use "make V=1" to debug this script
324 case "${KBUILD_VERBOSE}" in
330 if [ "$1" = "clean" ]; then
335 # We need access to CONFIG_ symbols
336 . include
/config
/auto.conf
340 if [ -r .version
]; then
341 VERSION
=$
(expr 0$
(cat .version
) + 1)
342 echo $VERSION > .version
348 # final build of init/
349 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj
=init need-builtin
=1
352 modpost_link vmlinux.o
353 objtool_link vmlinux.o
355 # modpost vmlinux.o to check for section mismatches
356 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX
=1
358 info MODINFO modules.
builtin.modinfo
359 ${OBJCOPY} -j .modinfo
-O binary vmlinux.o modules.
builtin.modinfo
360 info GEN modules.
builtin
361 # The second line aids cases where multiple modules share the same object.
362 tr '\0' '\n' < modules.
builtin.modinfo |
sed -n 's/^[[:alnum:]:_]*\.file=//p' |
363 tr ' ' '\n' |
uniq |
sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.
builtin
366 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
367 btf_vmlinux_bin_o
=.btf.vmlinux.bin.o
368 if ! gen_btf .tmp_vmlinux.btf
$btf_vmlinux_bin_o ; then
369 echo >&2 "Failed to generate BTF for vmlinux"
370 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
378 if [ -n "${CONFIG_KALLSYMS}" ]; then
381 # Generate section listing all symbols and add it into vmlinux
382 # It's a three step process:
383 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
384 # but __kallsyms is empty.
385 # Running kallsyms on that gives us .tmp_kallsyms1.o with
387 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
388 # the right size, but due to the added section, some
389 # addresses have shifted.
390 # From here, we generate a correct .tmp_kallsyms2.o
391 # 3) That link may have expanded the kernel image enough that
392 # more linker branch stubs / trampolines had to be added, which
393 # introduces new names, which further expands kallsyms. Do another
394 # pass if that is the case. In theory it's possible this results
395 # in even more stubs, but unlikely.
396 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
398 # 4) The correct ${kallsymso} is linked into the final vmlinux.
400 # a) Verify that the System.map from vmlinux matches the map from
407 size1
=$
(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
408 size2
=$
(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
410 if [ $size1 -ne $size2 ] ||
[ -n "${KALLSYMS_EXTRA_PASS}" ]; then
415 vmlinux_link vmlinux
"${kallsymso}" ${btf_vmlinux_bin_o}
418 if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then
420 ${RESOLVE_BTFIDS} vmlinux
423 if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
425 if ! sorttable vmlinux
; then
426 echo >&2 Failed to
sort kernel tables
431 info SYSMAP System.map
432 mksysmap vmlinux System.map
434 # step a (see comment above)
435 if [ -n "${CONFIG_KALLSYMS}" ]; then
436 mksysmap
${kallsyms_vmlinux} .tmp_System.map
438 if ! cmp -s System.map .tmp_System.map
; then
439 echo >&2 Inconsistent kallsyms data
440 echo >&2 Try
"make KALLSYMS_EXTRA_PASS=1" as a workaround