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 # +-< ${kallsymso} (see description in KALLSYMS section)
23 # vmlinux version (uname -v) cannot be updated during normal
24 # descending-into-subdirs phase since we do not yet know if we need to
26 # Therefore this step is delayed until just before final link of vmlinux.
28 # System.map is generated to document addresses of all kernel symbols
33 # Nice output in kbuild format
34 # Will be supressed by "make -s"
37 if [ "${quiet}" != "silent_" ]; then
38 printf " %-7s %s\n" "${1}" "${2}"
42 # Link of vmlinux.o used for section mismatch analysis
48 objects
="--whole-archive \
49 ${KBUILD_VMLINUX_OBJS} \
52 ${KBUILD_VMLINUX_LIBS} \
55 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
62 if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
64 if [ -z "${CONFIG_FRAME_POINTER}" ]; then
65 objtoolopt
="${objtoolopt} --no-fp"
67 if [ -n "${CONFIG_GCOV_KERNEL}" ]; then
68 objtoolopt
="${objtoolopt} --no-unreachable"
70 if [ -n "${CONFIG_RETPOLINE}" ]; then
71 objtoolopt
="${objtoolopt} --retpoline"
73 if [ -n "${CONFIG_X86_SMAP}" ]; then
74 objtoolopt
="${objtoolopt} --uaccess"
77 tools
/objtool
/objtool
${objtoolopt} ${1}
83 # ${2}, ${3}, ... - optional extra .o files
86 local lds
="${objtree}/${KBUILD_LDS}"
93 # skip output file argument
96 # The kallsyms linking does not need debug symbols included.
97 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
98 strip_debug
=-Wl,--strip-debug
101 if [ "${SRCARCH}" != "um" ]; then
102 objects
="--whole-archive \
103 ${KBUILD_VMLINUX_OBJS} \
106 ${KBUILD_VMLINUX_LIBS} \
110 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
111 ${strip_debug#-Wl,} \
115 objects
="-Wl,--whole-archive \
116 ${KBUILD_VMLINUX_OBJS} \
117 -Wl,--no-whole-archive \
119 ${KBUILD_VMLINUX_LIBS} \
123 ${CC} ${CFLAGS_vmlinux} \
128 -lutil -lrt -lpthread
133 # generate .BTF typeinfo from DWARF debuginfo
134 # ${1} - vmlinux image
135 # ${2} - file to dump raw BTF data into
140 if ! [ -x "$(command -v ${PAHOLE})" ]; then
141 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
145 pahole_ver
=$
(${PAHOLE} --version |
sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
146 if [ "${pahole_ver}" -lt "116" ]; then
147 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
154 LLVM_OBJCOPY
=${OBJCOPY} ${PAHOLE} -J ${1}
156 # Create ${2} which contains just .BTF section but no symbols. Add
157 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
158 # deletes all symbols including __start_BTF and __stop_BTF, which will
159 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
160 # objcopy warnings: "empty loadable segment detected at ..."
161 ${OBJCOPY} --only-section=.BTF
--set-section-flags .BTF
=alloc
,readonly \
162 --strip-all ${1} ${2} 2>/dev
/null
163 # Change e_type to ET_REL so that it can be used to link final vmlinux.
164 # Unlike GNU ld, lld does not allow an ET_EXEC input.
165 printf '\1' |
dd of
=${2} conv
=notrunc bs
=1 seek
=16 status
=none
168 # Create ${2} .o file with all symbols from the ${1} object file
174 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
175 kallsymopt
="${kallsymopt} --all-symbols"
178 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
179 kallsymopt
="${kallsymopt} --absolute-percpu"
182 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
183 kallsymopt
="${kallsymopt} --base-relative"
186 local aflags
="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
187 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
189 local afile
="`basename ${2} .o`.S"
191 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
192 ${CC} ${aflags} -c -o ${2} ${afile}
195 # Perform one step in kallsyms generation, including temporary linking of
199 kallsymso_prev
=${kallsymso}
200 kallsyms_vmlinux
=.tmp_vmlinux.kallsyms
${1}
201 kallsymso
=${kallsyms_vmlinux}.o
203 vmlinux_link
${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
204 kallsyms
${kallsyms_vmlinux} ${kallsymso}
207 # Create map file with all symbols from ${1}
208 # See mksymap for additional details
211 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
216 ${objtree}/scripts
/sorttable
${1}
219 # Delete output files in case of error
223 rm -f .tmp_System.map
232 if [ $?
-ne 0 ]; then
242 trap on_signals HUP INT QUIT TERM
244 # Use "make V=1" to debug this script
245 case "${KBUILD_VERBOSE}" in
251 if [ "$1" = "clean" ]; then
256 # We need access to CONFIG_ symbols
257 . include
/config
/auto.conf
261 if [ -r .version
]; then
262 VERSION
=$
(expr 0$
(cat .version
) + 1)
263 echo $VERSION > .version
269 # final build of init/
270 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj
=init need-builtin
=1
274 modpost_link vmlinux.o
275 objtool_link vmlinux.o
277 # modpost vmlinux.o to check for section mismatches
278 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX
=1
280 info MODINFO modules.
builtin.modinfo
281 ${OBJCOPY} -j .modinfo
-O binary vmlinux.o modules.
builtin.modinfo
282 info GEN modules.
builtin
283 # The second line aids cases where multiple modules share the same object.
284 tr '\0' '\n' < modules.
builtin.modinfo |
sed -n 's/^[[:alnum:]:_]*\.file=//p' |
285 tr ' ' '\n' |
uniq |
sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.
builtin
288 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
289 btf_vmlinux_bin_o
=.btf.vmlinux.bin.o
290 if ! gen_btf .tmp_vmlinux.btf
$btf_vmlinux_bin_o ; then
291 echo >&2 "Failed to generate BTF for vmlinux"
292 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
300 if [ -n "${CONFIG_KALLSYMS}" ]; then
303 # Generate section listing all symbols and add it into vmlinux
304 # It's a three step process:
305 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
306 # but __kallsyms is empty.
307 # Running kallsyms on that gives us .tmp_kallsyms1.o with
309 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
310 # the right size, but due to the added section, some
311 # addresses have shifted.
312 # From here, we generate a correct .tmp_kallsyms2.o
313 # 3) That link may have expanded the kernel image enough that
314 # more linker branch stubs / trampolines had to be added, which
315 # introduces new names, which further expands kallsyms. Do another
316 # pass if that is the case. In theory it's possible this results
317 # in even more stubs, but unlikely.
318 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
320 # 4) The correct ${kallsymso} is linked into the final vmlinux.
322 # a) Verify that the System.map from vmlinux matches the map from
329 size1
=$
(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
330 size2
=$
(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
332 if [ $size1 -ne $size2 ] ||
[ -n "${KALLSYMS_EXTRA_PASS}" ]; then
337 vmlinux_link vmlinux
"${kallsymso}" ${btf_vmlinux_bin_o}
340 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
342 ${RESOLVE_BTFIDS} vmlinux
345 if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
347 if ! sorttable vmlinux
; then
348 echo >&2 Failed to
sort kernel tables
353 info SYSMAP System.map
354 mksysmap vmlinux System.map
356 # step a (see comment above)
357 if [ -n "${CONFIG_KALLSYMS}" ]; then
358 mksysmap
${kallsyms_vmlinux} .tmp_System.map
360 if ! cmp -s System.map .tmp_System.map
; then
361 echo >&2 Inconsistent kallsyms data
362 echo >&2 Try
"make KALLSYMS_EXTRA_PASS=1" as a workaround