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}
59 # ${1} - optional extra .o files
63 local lds="${objtree}/${KBUILD_LDS}"
66 if [ "${SRCARCH}" != "um" ]; then
67 objects="--whole-archive \
68 ${KBUILD_VMLINUX_OBJS} \
71 ${KBUILD_VMLINUX_LIBS} \
75 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
78 objects="-Wl,--whole-archive \
79 ${KBUILD_VMLINUX_OBJS} \
80 -Wl,--no-whole-archive \
82 ${KBUILD_VMLINUX_LIBS} \
86 ${CC} ${CFLAGS_vmlinux} -o ${2} \
94 # generate .BTF typeinfo from DWARF debuginfo
99 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
100 if [ "${pahole_ver}" -lt "113" ]; then
101 info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
106 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
109 # Create ${2} .o file with all symbols from the ${1} object file
115 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
116 kallsymopt="${kallsymopt} --all-symbols"
119 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
120 kallsymopt="${kallsymopt} --absolute-percpu"
123 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
124 kallsymopt="${kallsymopt} --base-relative"
127 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
128 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
130 local afile="`basename ${2} .o`.S"
132 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
133 ${CC} ${aflags} -c -o ${2} ${afile}
136 # Create map file with all symbols from ${1}
137 # See mksymap for additional details
140 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
145 ${objtree}/scripts/sortextable ${1}
148 # Delete output files in case of error
151 rm -f .tmp_System.map
161 if [ $? -ne 0 ]; then
171 trap on_signals HUP INT QUIT TERM
175 # Use "make V=1" to debug this script
176 case "${KBUILD_VERBOSE}" in
182 if [ "$1" = "clean" ]; then
187 # We need access to CONFIG_ symbols
188 . include/config/auto.conf
192 if [ -r .version ]; then
193 VERSION=$(expr 0$(cat .version) + 1)
194 echo $VERSION > .version
200 # final build of init/
201 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
205 modpost_link vmlinux.o
207 # modpost vmlinux.o to check for section mismatches
208 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
212 if [ -n "${CONFIG_KALLSYMS}" ]; then
215 # Generate section listing all symbols and add it into vmlinux
216 # It's a three step process:
217 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
218 # but __kallsyms is empty.
219 # Running kallsyms on that gives us .tmp_kallsyms1.o with
221 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
222 # the right size, but due to the added section, some
223 # addresses have shifted.
224 # From here, we generate a correct .tmp_kallsyms2.o
225 # 3) That link may have expanded the kernel image enough that
226 # more linker branch stubs / trampolines had to be added, which
227 # introduces new names, which further expands kallsyms. Do another
228 # pass if that is the case. In theory it's possible this results
229 # in even more stubs, but unlikely.
230 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
232 # 4) The correct ${kallsymso} is linked into the final vmlinux.
234 # a) Verify that the System.map from vmlinux matches the map from
237 kallsymso=.tmp_kallsyms2.o
238 kallsyms_vmlinux=.tmp_vmlinux2
241 vmlinux_link "" .tmp_vmlinux1
242 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
245 vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
246 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
249 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
250 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)
252 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
253 kallsymso=.tmp_kallsyms3.o
254 kallsyms_vmlinux=.tmp_vmlinux3
256 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
258 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
263 vmlinux_link "${kallsymso}" vmlinux
265 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
269 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
274 info SYSMAP System.map
275 mksysmap vmlinux System.map
277 # step a (see comment above)
278 if [ -n "${CONFIG_KALLSYMS}" ]; then
279 mksysmap ${kallsyms_vmlinux} .tmp_System.map
281 if ! cmp -s System.map .tmp_System.map; then
282 echo >&2 Inconsistent kallsyms data
283 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround