1#!/bin/sh
  2# SPDX-License-Identifier: GPL-2.0
  3#
  4# link vmlinux
  5#
  6# vmlinux is linked from the objects in vmlinux.a and $(KBUILD_VMLINUX_LIBS).
  7# vmlinux.a contains objects that are linked unconditionally.
 
  8# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
  9# (not within --whole-archive), and do not require symbol indexes added.
 10#
 11# vmlinux
 12#   ^
 13#   |
 14#   +--< vmlinux.a
 
 15#   |
 16#   +--< $(KBUILD_VMLINUX_LIBS)
 17#   |    +--< lib/lib.a + more
 18#   |
 19#   +-< ${kallsymso} (see description in KALLSYMS section)
 20#
 21# vmlinux version (uname -v) cannot be updated during normal
 22# descending-into-subdirs phase since we do not yet know if we need to
 23# update vmlinux.
 24# Therefore this step is delayed until just before final link of vmlinux.
 25#
 26# System.map is generated to document addresses of all kernel symbols
 27
 28# Error out on error
 29set -e
 30
 31LD="$1"
 32KBUILD_LDFLAGS="$2"
 33LDFLAGS_vmlinux="$3"
 34
 35is_enabled() {
 36	grep -q "^$1=y" include/config/auto.conf
 37}
 38
 39# Nice output in kbuild format
 40# Will be supressed by "make -s"
 41info()
 42{
 43	printf "  %-7s %s\n" "${1}" "${2}"
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 44}
 45
 46# Link of vmlinux
 47# ${1} - output file
 48# ${2}, ${3}, ... - optional extra .o files
 49vmlinux_link()
 50{
 
 51	local output=${1}
 52	local objs
 53	local libs
 54	local ld
 55	local ldflags
 56	local ldlibs
 57
 58	info LD ${output}
 59
 60	# skip output file argument
 61	shift
 62
 63	if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
 64		# Use vmlinux.o instead of performing the slow LTO link again.
 65		objs=vmlinux.o
 66		libs=
 67	else
 68		objs=vmlinux.a
 69		libs="${KBUILD_VMLINUX_LIBS}"
 70	fi
 71
 72	if is_enabled CONFIG_MODULES; then
 73		objs="${objs} .vmlinux.export.o"
 74	fi
 75
 76	objs="${objs} init/version-timestamp.o"
 77
 78	if [ "${SRCARCH}" = "um" ]; then
 79		wl=-Wl,
 80		ld="${CC}"
 81		ldflags="${CFLAGS_vmlinux}"
 82		ldlibs="-lutil -lrt -lpthread"
 83	else
 84		wl=
 85		ld="${LD}"
 86		ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
 87		ldlibs=
 88	fi
 89
 90	ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"
 91
 92	# The kallsyms linking does not need debug symbols included.
 93	if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
 94		ldflags="${ldflags} ${wl}--strip-debug"
 
 
 
 95	fi
 96
 97	if is_enabled CONFIG_VMLINUX_MAP; then
 98		ldflags="${ldflags} ${wl}-Map=${output}.map"
 99	fi
100
101	${ld} ${ldflags} -o ${output}					\
102		${wl}--whole-archive ${objs} ${wl}--no-whole-archive	\
103		${wl}--start-group ${libs} ${wl}--end-group		\
104		$@ ${ldlibs}
105}
106
107# generate .BTF typeinfo from DWARF debuginfo
108# ${1} - vmlinux image
109# ${2} - file to dump raw BTF data into
110gen_btf()
111{
112	local pahole_ver
 
113
114	if ! [ -x "$(command -v ${PAHOLE})" ]; then
115		echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
116		return 1
117	fi
118
119	pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
120	if [ "${pahole_ver}" -lt "116" ]; then
121		echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
122		return 1
123	fi
124
125	vmlinux_link ${1}
126
127	info "BTF" ${2}
128	LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
 
129
130	# Create ${2} which contains just .BTF section but no symbols. Add
131	# SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
132	# deletes all symbols including __start_BTF and __stop_BTF, which will
133	# be redefined in the linker script. Add 2>/dev/null to suppress GNU
134	# objcopy warnings: "empty loadable segment detected at ..."
135	${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
136		--strip-all ${1} ${2} 2>/dev/null
137	# Change e_type to ET_REL so that it can be used to link final vmlinux.
138	# GNU ld 2.35+ and lld do not allow an ET_EXEC input.
139	if is_enabled CONFIG_CPU_BIG_ENDIAN; then
140		et_rel='\0\1'
141	else
142		et_rel='\1\0'
143	fi
144	printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none
145}
146
147# Create ${2} .S file with all symbols from the ${1} object file
148kallsyms()
149{
 
150	local kallsymopt;
151
152	if is_enabled CONFIG_KALLSYMS_ALL; then
153		kallsymopt="${kallsymopt} --all-symbols"
154	fi
155
156	if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then
157		kallsymopt="${kallsymopt} --absolute-percpu"
158	fi
159
160	if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then
161		kallsymopt="${kallsymopt} --base-relative"
162	fi
163
164	if is_enabled CONFIG_LTO_CLANG; then
165		kallsymopt="${kallsymopt} --lto-clang"
166	fi
167
168	info KSYMS ${2}
169	scripts/kallsyms ${kallsymopt} ${1} > ${2}
 
 
170}
171
172# Perform one step in kallsyms generation, including temporary linking of
173# vmlinux.
174kallsyms_step()
175{
176	kallsymso_prev=${kallsymso}
177	kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
178	kallsymso=${kallsyms_vmlinux}.o
179	kallsyms_S=${kallsyms_vmlinux}.S
180
181	vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
182	mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms ${kallsymso_prev}
183	kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S}
184
185	info AS ${kallsyms_S}
186	${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
187	      ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
188	      -c -o ${kallsymso} ${kallsyms_S}
189}
190
191# Create map file with all symbols from ${1}
192# See mksymap for additional details
193mksysmap()
194{
195	info NM ${2}
196	${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} ${3}
197}
198
199sorttable()
200{
201	${objtree}/scripts/sorttable ${1}
202}
203
204# Delete output files in case of error
205cleanup()
206{
207	rm -f .btf.*
 
 
 
208	rm -f System.map
209	rm -f vmlinux
210	rm -f vmlinux.map
 
 
 
 
 
 
 
 
 
 
 
 
 
211}
 
212
 
 
213# Use "make V=1" to debug this script
214case "${KBUILD_VERBOSE}" in
215*1*)
216	set -x
217	;;
218esac
219
220if [ "$1" = "clean" ]; then
221	cleanup
222	exit 0
223fi
224
225${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
226
227btf_vmlinux_bin_o=""
228if is_enabled CONFIG_DEBUG_INFO_BTF; then
229	btf_vmlinux_bin_o=.btf.vmlinux.bin.o
230	if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
231		echo >&2 "Failed to generate BTF for vmlinux"
232		echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
233		exit 1
234	fi
235fi
236
237kallsymso=""
238kallsymso_prev=""
239kallsyms_vmlinux=""
240if is_enabled CONFIG_KALLSYMS; then
241
242	# kallsyms support
243	# Generate section listing all symbols and add it into vmlinux
244	# It's a three step process:
245	# 1)  Link .tmp_vmlinux.kallsyms1 so it has all symbols and sections,
246	#     but __kallsyms is empty.
247	#     Running kallsyms on that gives us .tmp_kallsyms1.o with
248	#     the right size
249	# 2)  Link .tmp_vmlinux.kallsyms2 so it now has a __kallsyms section of
250	#     the right size, but due to the added section, some
251	#     addresses have shifted.
252	#     From here, we generate a correct .tmp_vmlinux.kallsyms2.o
253	# 3)  That link may have expanded the kernel image enough that
254	#     more linker branch stubs / trampolines had to be added, which
255	#     introduces new names, which further expands kallsyms. Do another
256	#     pass if that is the case. In theory it's possible this results
257	#     in even more stubs, but unlikely.
258	#     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
259	#     other bugs.
260	# 4)  The correct ${kallsymso} is linked into the final vmlinux.
261	#
262	# a)  Verify that the System.map from vmlinux matches the map from
263	#     ${kallsymso}.
264
265	kallsyms_step 1
266	kallsyms_step 2
267
268	# step 3
269	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
270	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
271
272	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
273		kallsyms_step 3
274	fi
275fi
276
277vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
278
279# fill in BTF IDs
280if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then
281	info BTFIDS vmlinux
282	${RESOLVE_BTFIDS} vmlinux
283fi
284
285mksysmap vmlinux System.map ${kallsymso}
286
287if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
288	info SORTTAB vmlinux
289	if ! sorttable vmlinux; then
290		echo >&2 Failed to sort kernel tables
291		exit 1
292	fi
293fi
294
295# step a (see comment above)
296if is_enabled CONFIG_KALLSYMS; then
297	if ! cmp -s System.map ${kallsyms_vmlinux}.syms; then
 
 
298		echo >&2 Inconsistent kallsyms data
299		echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
300		exit 1
301	fi
302fi
303
304# For fixdep
305echo "vmlinux: $0" > .vmlinux.d

  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
 
 
 
 
 
 
 
 
 33# Nice output in kbuild format
 34# Will be supressed by "make -s"
 35info()
 36{
 37	if [ "${quiet}" != "silent_" ]; then
 38		printf "  %-7s %s\n" "${1}" "${2}"
 39	fi
 40}
 41
 42# Link of vmlinux.o used for section mismatch analysis
 43# ${1} output file
 44modpost_link()
 45{
 46	local objects
 47
 48	objects="--whole-archive				\
 49		${KBUILD_VMLINUX_OBJS}				\
 50		--no-whole-archive				\
 51		--start-group					\
 52		${KBUILD_VMLINUX_LIBS}				\
 53		--end-group"
 54
 55	${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
 56}
 57
 58# Link of vmlinux
 59# ${1} - output file
 60# ${2}, ${3}, ... - optional extra .o files
 61vmlinux_link()
 62{
 63	local lds="${objtree}/${KBUILD_LDS}"
 64	local output=${1}
 65	local objects
 
 
 
 
 66
 67	info LD ${output}
 68
 69	# skip output file argument
 70	shift
 71
 72	if [ "${SRCARCH}" != "um" ]; then
 73		objects="--whole-archive			\
 74			${KBUILD_VMLINUX_OBJS}			\
 75			--no-whole-archive			\
 76			--start-group				\
 77			${KBUILD_VMLINUX_LIBS}			\
 78			--end-group				\
 79			${@}"
 80
 81		${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}	\
 82			-o ${output}				\
 83			-T ${lds} ${objects}
 
 
 
 
 
 
 
 
 84	else
 85		objects="-Wl,--whole-archive			\
 86			${KBUILD_VMLINUX_OBJS}			\
 87			-Wl,--no-whole-archive			\
 88			-Wl,--start-group			\
 89			${KBUILD_VMLINUX_LIBS}			\
 90			-Wl,--end-group				\
 91			${@}"
 92
 93		${CC} ${CFLAGS_vmlinux}				\
 94			-o ${output}				\
 95			-Wl,-T,${lds}				\
 96			${objects}				\
 97			-lutil -lrt -lpthread
 98		rm -f linux
 99	fi
 
 
 
 
 
 
 
 
 
100}
101
102# generate .BTF typeinfo from DWARF debuginfo
103# ${1} - vmlinux image
104# ${2} - file to dump raw BTF data into
105gen_btf()
106{
107	local pahole_ver
108	local bin_arch
109
110	if ! [ -x "$(command -v ${PAHOLE})" ]; then
111		info "BTF" "${1}: pahole (${PAHOLE}) is not available"
112		return 1
113	fi
114
115	pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
116	if [ "${pahole_ver}" -lt "113" ]; then
117		info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
118		return 1
119	fi
120
 
 
121	info "BTF" ${2}
122	vmlinux_link ${1}
123	LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
124
125	# dump .BTF section into raw binary file to link with final vmlinux
126	bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \
127		cut -d, -f1 | cut -d' ' -f2)
128	bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \
129		awk '{print $4}')
130	${OBJCOPY} --dump-section .BTF=.btf.vmlinux.bin ${1} 2>/dev/null
131	${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \
132		--rename-section .data=.BTF .btf.vmlinux.bin ${2}
 
 
 
 
 
 
 
133}
134
135# Create ${2} .o file with all symbols from the ${1} object file
136kallsyms()
137{
138	info KSYM ${2}
139	local kallsymopt;
140
141	if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
142		kallsymopt="${kallsymopt} --all-symbols"
143	fi
144
145	if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
146		kallsymopt="${kallsymopt} --absolute-percpu"
147	fi
148
149	if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
150		kallsymopt="${kallsymopt} --base-relative"
151	fi
152
153	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
154		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
 
155
156	local afile="`basename ${2} .o`.S"
157
158	${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
159	${CC} ${aflags} -c -o ${2} ${afile}
160}
161
162# Perform one step in kallsyms generation, including temporary linking of
163# vmlinux.
164kallsyms_step()
165{
166	kallsymso_prev=${kallsymso}
167	kallsymso=.tmp_kallsyms${1}.o
168	kallsyms_vmlinux=.tmp_vmlinux${1}
 
169
170	vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
171	kallsyms ${kallsyms_vmlinux} ${kallsymso}
 
 
 
 
 
 
172}
173
174# Create map file with all symbols from ${1}
175# See mksymap for additional details
176mksysmap()
177{
178	${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 
179}
180
181sortextable()
182{
183	${objtree}/scripts/sortextable ${1}
184}
185
186# Delete output files in case of error
187cleanup()
188{
189	rm -f .btf.*
190	rm -f .tmp_System.map
191	rm -f .tmp_kallsyms*
192	rm -f .tmp_vmlinux*
193	rm -f System.map
194	rm -f vmlinux
195	rm -f vmlinux.o
196}
197
198on_exit()
199{
200	if [ $? -ne 0 ]; then
201		cleanup
202	fi
203}
204trap on_exit EXIT
205
206on_signals()
207{
208	exit 1
209}
210trap on_signals HUP INT QUIT TERM
211
212#
213#
214# Use "make V=1" to debug this script
215case "${KBUILD_VERBOSE}" in
216*1*)
217	set -x
218	;;
219esac
220
221if [ "$1" = "clean" ]; then
222	cleanup
223	exit 0
224fi
225
226# We need access to CONFIG_ symbols
227. include/config/auto.conf
228
229# Update version
230info GEN .version
231if [ -r .version ]; then
232	VERSION=$(expr 0$(cat .version) + 1)
233	echo $VERSION > .version
234else
235	rm -f .version
236	echo 1 > .version
237fi;
238
239# final build of init/
240${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
241
242#link vmlinux.o
243info LD vmlinux.o
244modpost_link vmlinux.o
245
246# modpost vmlinux.o to check for section mismatches
247${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
248
249info MODINFO modules.builtin.modinfo
250${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
251
252btf_vmlinux_bin_o=""
253if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
254	if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then
255		btf_vmlinux_bin_o=.btf.vmlinux.bin.o
 
 
 
256	fi
257fi
258
259kallsymso=""
260kallsymso_prev=""
261kallsyms_vmlinux=""
262if [ -n "${CONFIG_KALLSYMS}" ]; then
263
264	# kallsyms support
265	# Generate section listing all symbols and add it into vmlinux
266	# It's a three step process:
267	# 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
268	#     but __kallsyms is empty.
269	#     Running kallsyms on that gives us .tmp_kallsyms1.o with
270	#     the right size
271	# 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
272	#     the right size, but due to the added section, some
273	#     addresses have shifted.
274	#     From here, we generate a correct .tmp_kallsyms2.o
275	# 3)  That link may have expanded the kernel image enough that
276	#     more linker branch stubs / trampolines had to be added, which
277	#     introduces new names, which further expands kallsyms. Do another
278	#     pass if that is the case. In theory it's possible this results
279	#     in even more stubs, but unlikely.
280	#     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
281	#     other bugs.
282	# 4)  The correct ${kallsymso} is linked into the final vmlinux.
283	#
284	# a)  Verify that the System.map from vmlinux matches the map from
285	#     ${kallsymso}.
286
287	kallsyms_step 1
288	kallsyms_step 2
289
290	# step 3
291	size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
292	size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
293
294	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
295		kallsyms_step 3
296	fi
297fi
298
299vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
300
301if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
302	info SORTEX vmlinux
303	sortextable vmlinux
 
304fi
305
306info SYSMAP System.map
307mksysmap vmlinux System.map
 
 
 
 
 
 
 
308
309# step a (see comment above)
310if [ -n "${CONFIG_KALLSYMS}" ]; then
311	mksysmap ${kallsyms_vmlinux} .tmp_System.map
312
313	if ! cmp -s System.map .tmp_System.map; then
314		echo >&2 Inconsistent kallsyms data
315		echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
316		exit 1
317	fi
318fi