2 # SPDX-License-Identifier: GPL-2.0
6 # vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and
7 # $(KBUILD_VMLINUX_MAIN) and $(KBUILD_VMLINUX_LIBS). Most are built-in.a files
8 # from top-level directories in the kernel tree, others are specified in
9 # arch/$(ARCH)/Makefile. Ordering when linking is important, and
10 # $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
11 # which are linked conditionally (not within --whole-archive), and do not
12 # require symbol indexes added.
17 # +-< $(KBUILD_VMLINUX_INIT)
18 # | +--< init/version.o + more
20 # +--< $(KBUILD_VMLINUX_MAIN)
21 # | +--< drivers/built-in.a mm/built-in.a + more
23 # +--< $(KBUILD_VMLINUX_LIBS)
24 # | +--< lib/lib.a + more
26 # +-< ${kallsymso} (see description in KALLSYMS section)
28 # vmlinux version (uname -v) cannot be updated during normal
29 # descending-into-subdirs phase since we do not yet know if we need to
31 # Therefore this step is delayed until just before final link of vmlinux.
33 # System.map is generated to document addresses of all kernel symbols
38 # Nice output in kbuild format
39 # Will be supressed by "make -s"
42 if [ "${quiet}" != "silent_" ]; then
43 printf " %-7s %s\n" ${1} ${2}
47 # Thin archive build here makes a final archive with symbol table and indexes
48 # from vmlinux objects INIT and MAIN, which can be used as input to linker.
49 # KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
52 # Traditional incremental style of link does not require this step
54 # built-in.a output file
60 ${AR} rcsTP${KBUILD_ARFLAGS} built-in.a \
61 ${KBUILD_VMLINUX_INIT} \
62 ${KBUILD_VMLINUX_MAIN}
65 # Link of vmlinux.o used for section mismatch analysis
71 objects="--whole-archive \
75 ${KBUILD_VMLINUX_LIBS} \
78 ${LD} ${LDFLAGS} -r -o ${1} ${objects}
82 # ${1} - optional extra .o files
86 local lds="${objtree}/${KBUILD_LDS}"
89 if [ "${SRCARCH}" != "um" ]; then
90 objects="--whole-archive \
94 ${KBUILD_VMLINUX_LIBS} \
98 ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
101 objects="-Wl,--whole-archive \
103 -Wl,--no-whole-archive \
105 ${KBUILD_VMLINUX_LIBS} \
109 ${CC} ${CFLAGS_vmlinux} -o ${2} \
112 -lutil -lrt -lpthread
118 # Create ${2} .o file with all symbols from the ${1} object file
124 if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
125 kallsymopt="${kallsymopt} --symbol-prefix=_"
128 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
129 kallsymopt="${kallsymopt} --all-symbols"
132 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
133 kallsymopt="${kallsymopt} --absolute-percpu"
136 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
137 kallsymopt="${kallsymopt} --base-relative"
140 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
141 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
143 local afile="`basename ${2} .o`.S"
145 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
146 ${CC} ${aflags} -c -o ${2} ${afile}
149 # Create map file with all symbols from ${1}
150 # See mksymap for additional details
153 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
158 ${objtree}/scripts/sortextable ${1}
161 # Delete output files in case of error
164 rm -f .tmp_System.map
175 if [ $? -ne 0 ]; then
185 trap on_signals HUP INT QUIT TERM
189 # Use "make V=1" to debug this script
190 case "${KBUILD_VERBOSE}" in
196 if [ "$1" = "clean" ]; then
201 # We need access to CONFIG_ symbols
202 case "${KCONFIG_CONFIG}" in
204 . "${KCONFIG_CONFIG}"
207 # Force using a file from the current directory
208 . "./${KCONFIG_CONFIG}"
213 if [ -r .version ]; then
214 VERSION=$(expr 0$(cat .version) + 1)
215 echo $VERSION > .version
221 # final build of init/
222 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
228 modpost_link vmlinux.o
230 # modpost vmlinux.o to check for section mismatches
231 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
235 if [ -n "${CONFIG_KALLSYMS}" ]; then
238 # Generate section listing all symbols and add it into vmlinux
239 # It's a three step process:
240 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
241 # but __kallsyms is empty.
242 # Running kallsyms on that gives us .tmp_kallsyms1.o with
244 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
245 # the right size, but due to the added section, some
246 # addresses have shifted.
247 # From here, we generate a correct .tmp_kallsyms2.o
248 # 3) That link may have expanded the kernel image enough that
249 # more linker branch stubs / trampolines had to be added, which
250 # introduces new names, which further expands kallsyms. Do another
251 # pass if that is the case. In theory it's possible this results
252 # in even more stubs, but unlikely.
253 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
255 # 4) The correct ${kallsymso} is linked into the final vmlinux.
257 # a) Verify that the System.map from vmlinux matches the map from
260 kallsymso=.tmp_kallsyms2.o
261 kallsyms_vmlinux=.tmp_vmlinux2
264 vmlinux_link "" .tmp_vmlinux1
265 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
268 vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
269 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
272 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
273 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)
275 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
276 kallsymso=.tmp_kallsyms3.o
277 kallsyms_vmlinux=.tmp_vmlinux3
279 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
281 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
286 vmlinux_link "${kallsymso}" vmlinux
288 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
293 info SYSMAP System.map
294 mksysmap vmlinux System.map
296 # step a (see comment above)
297 if [ -n "${CONFIG_KALLSYMS}" ]; then
298 mksysmap ${kallsyms_vmlinux} .tmp_System.map
300 if ! cmp -s System.map .tmp_System.map; then
301 echo >&2 Inconsistent kallsyms data
302 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround