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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
33LD="$1"
34KBUILD_LDFLAGS="$2"
35LDFLAGS_vmlinux="$3"
36
37# Nice output in kbuild format
38# Will be supressed by "make -s"
39info()
40{
41 if [ "${quiet}" != "silent_" ]; then
42 printf " %-7s %s\n" "${1}" "${2}"
43 fi
44}
45
46# Link of vmlinux.o used for section mismatch analysis
47# ${1} output file
48modpost_link()
49{
50 local objects
51
52 objects="--whole-archive \
53 ${KBUILD_VMLINUX_OBJS} \
54 --no-whole-archive \
55 --start-group \
56 ${KBUILD_VMLINUX_LIBS} \
57 --end-group"
58
59 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
60}
61
62objtool_link()
63{
64 local objtoolopt;
65
66 if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
67 objtoolopt="check"
68 if [ -z "${CONFIG_FRAME_POINTER}" ]; then
69 objtoolopt="${objtoolopt} --no-fp"
70 fi
71 if [ -n "${CONFIG_GCOV_KERNEL}" ]; then
72 objtoolopt="${objtoolopt} --no-unreachable"
73 fi
74 if [ -n "${CONFIG_RETPOLINE}" ]; then
75 objtoolopt="${objtoolopt} --retpoline"
76 fi
77 if [ -n "${CONFIG_X86_SMAP}" ]; then
78 objtoolopt="${objtoolopt} --uaccess"
79 fi
80 info OBJTOOL ${1}
81 tools/objtool/objtool ${objtoolopt} ${1}
82 fi
83}
84
85# Link of vmlinux
86# ${1} - output file
87# ${2}, ${3}, ... - optional extra .o files
88vmlinux_link()
89{
90 local lds="${objtree}/${KBUILD_LDS}"
91 local output=${1}
92 local objects
93 local strip_debug
94
95 info LD ${output}
96
97 # skip output file argument
98 shift
99
100 # The kallsyms linking does not need debug symbols included.
101 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
102 strip_debug=-Wl,--strip-debug
103 fi
104
105 if [ "${SRCARCH}" != "um" ]; then
106 objects="--whole-archive \
107 ${KBUILD_VMLINUX_OBJS} \
108 --no-whole-archive \
109 --start-group \
110 ${KBUILD_VMLINUX_LIBS} \
111 --end-group \
112 ${@}"
113
114 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
115 ${strip_debug#-Wl,} \
116 -o ${output} \
117 -T ${lds} ${objects}
118 else
119 objects="-Wl,--whole-archive \
120 ${KBUILD_VMLINUX_OBJS} \
121 -Wl,--no-whole-archive \
122 -Wl,--start-group \
123 ${KBUILD_VMLINUX_LIBS} \
124 -Wl,--end-group \
125 ${@}"
126
127 ${CC} ${CFLAGS_vmlinux} \
128 ${strip_debug} \
129 -o ${output} \
130 -Wl,-T,${lds} \
131 ${objects} \
132 -lutil -lrt -lpthread
133 rm -f linux
134 fi
135}
136
137# generate .BTF typeinfo from DWARF debuginfo
138# ${1} - vmlinux image
139# ${2} - file to dump raw BTF data into
140gen_btf()
141{
142 local pahole_ver
143
144 if ! [ -x "$(command -v ${PAHOLE})" ]; then
145 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
146 return 1
147 fi
148
149 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
150 if [ "${pahole_ver}" -lt "116" ]; then
151 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
152 return 1
153 fi
154
155 vmlinux_link ${1}
156
157 info "BTF" ${2}
158 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
159
160 # Create ${2} which contains just .BTF section but no symbols. Add
161 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
162 # deletes all symbols including __start_BTF and __stop_BTF, which will
163 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
164 # objcopy warnings: "empty loadable segment detected at ..."
165 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
166 --strip-all ${1} ${2} 2>/dev/null
167 # Change e_type to ET_REL so that it can be used to link final vmlinux.
168 # Unlike GNU ld, lld does not allow an ET_EXEC input.
169 printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none
170}
171
172# Create ${2} .o file with all symbols from the ${1} object file
173kallsyms()
174{
175 info KSYM ${2}
176 local kallsymopt;
177
178 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
179 kallsymopt="${kallsymopt} --all-symbols"
180 fi
181
182 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
183 kallsymopt="${kallsymopt} --absolute-percpu"
184 fi
185
186 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
187 kallsymopt="${kallsymopt} --base-relative"
188 fi
189
190 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
191 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
192
193 local afile="`basename ${2} .o`.S"
194
195 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
196 ${CC} ${aflags} -c -o ${2} ${afile}
197}
198
199# Perform one step in kallsyms generation, including temporary linking of
200# vmlinux.
201kallsyms_step()
202{
203 kallsymso_prev=${kallsymso}
204 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
205 kallsymso=${kallsyms_vmlinux}.o
206
207 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
208 kallsyms ${kallsyms_vmlinux} ${kallsymso}
209}
210
211# Create map file with all symbols from ${1}
212# See mksymap for additional details
213mksysmap()
214{
215 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
216}
217
218sorttable()
219{
220 ${objtree}/scripts/sorttable ${1}
221}
222
223# Delete output files in case of error
224cleanup()
225{
226 rm -f .btf.*
227 rm -f .tmp_System.map
228 rm -f .tmp_vmlinux*
229 rm -f System.map
230 rm -f vmlinux
231 rm -f vmlinux.o
232}
233
234on_exit()
235{
236 if [ $? -ne 0 ]; then
237 cleanup
238 fi
239}
240trap on_exit EXIT
241
242on_signals()
243{
244 exit 1
245}
246trap on_signals HUP INT QUIT TERM
247
248# Use "make V=1" to debug this script
249case "${KBUILD_VERBOSE}" in
250*1*)
251 set -x
252 ;;
253esac
254
255if [ "$1" = "clean" ]; then
256 cleanup
257 exit 0
258fi
259
260# We need access to CONFIG_ symbols
261. include/config/auto.conf
262
263# Update version
264info GEN .version
265if [ -r .version ]; then
266 VERSION=$(expr 0$(cat .version) + 1)
267 echo $VERSION > .version
268else
269 rm -f .version
270 echo 1 > .version
271fi;
272
273# final build of init/
274${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
275
276#link vmlinux.o
277info LD vmlinux.o
278modpost_link vmlinux.o
279objtool_link vmlinux.o
280
281# modpost vmlinux.o to check for section mismatches
282${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
283
284info MODINFO modules.builtin.modinfo
285${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
286info GEN modules.builtin
287# The second line aids cases where multiple modules share the same object.
288tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
289 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
290
291btf_vmlinux_bin_o=""
292if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
293 btf_vmlinux_bin_o=.btf.vmlinux.bin.o
294 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
295 echo >&2 "Failed to generate BTF for vmlinux"
296 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
297 exit 1
298 fi
299fi
300
301kallsymso=""
302kallsymso_prev=""
303kallsyms_vmlinux=""
304if [ -n "${CONFIG_KALLSYMS}" ]; then
305
306 # kallsyms support
307 # Generate section listing all symbols and add it into vmlinux
308 # It's a three step process:
309 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
310 # but __kallsyms is empty.
311 # Running kallsyms on that gives us .tmp_kallsyms1.o with
312 # the right size
313 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
314 # the right size, but due to the added section, some
315 # addresses have shifted.
316 # From here, we generate a correct .tmp_kallsyms2.o
317 # 3) That link may have expanded the kernel image enough that
318 # more linker branch stubs / trampolines had to be added, which
319 # introduces new names, which further expands kallsyms. Do another
320 # pass if that is the case. In theory it's possible this results
321 # in even more stubs, but unlikely.
322 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
323 # other bugs.
324 # 4) The correct ${kallsymso} is linked into the final vmlinux.
325 #
326 # a) Verify that the System.map from vmlinux matches the map from
327 # ${kallsymso}.
328
329 kallsyms_step 1
330 kallsyms_step 2
331
332 # step 3
333 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
334 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
335
336 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
337 kallsyms_step 3
338 fi
339fi
340
341vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
342
343# fill in BTF IDs
344if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
345info BTFIDS vmlinux
346${RESOLVE_BTFIDS} vmlinux
347fi
348
349if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
350 info SORTTAB vmlinux
351 if ! sorttable vmlinux; then
352 echo >&2 Failed to sort kernel tables
353 exit 1
354 fi
355fi
356
357info SYSMAP System.map
358mksysmap vmlinux System.map
359
360# step a (see comment above)
361if [ -n "${CONFIG_KALLSYMS}" ]; then
362 mksysmap ${kallsyms_vmlinux} .tmp_System.map
363
364 if ! cmp -s System.map .tmp_System.map; then
365 echo >&2 Inconsistent kallsyms data
366 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
367 exit 1
368 fi
369fi
1#!/bin/sh
2#
3# link vmlinux
4#
5# vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and
6# $(KBUILD_VMLINUX_MAIN). Most are built-in.o files from top-level directories
7# in the kernel tree, others are specified in arch/$(ARCH)/Makefile.
8# Ordering when linking is important, and $(KBUILD_VMLINUX_INIT) must be first.
9#
10# vmlinux
11# ^
12# |
13# +-< $(KBUILD_VMLINUX_INIT)
14# | +--< init/version.o + more
15# |
16# +--< $(KBUILD_VMLINUX_MAIN)
17# | +--< drivers/built-in.o mm/built-in.o + more
18# |
19# +-< ${kallsymso} (see description in KALLSYMS section)
20#
21# vmlinux version (uname -v) cannot be updated during normal
22# descending-into-subdirs phase since we do not yet know if we need to
23# update vmlinux.
24# Therefore this step is delayed until just before final link of vmlinux.
25#
26# System.map is generated to document addresses of all kernel symbols
27
28# Error out on error
29set -e
30
31# Nice output in kbuild format
32# Will be supressed by "make -s"
33info()
34{
35 if [ "${quiet}" != "silent_" ]; then
36 printf " %-7s %s\n" ${1} ${2}
37 fi
38}
39
40# Thin archive build here makes a final archive with
41# symbol table and indexes from vmlinux objects, which can be
42# used as input to linker.
43#
44# Traditional incremental style of link does not require this step
45#
46# built-in.o output file
47#
48archive_builtin()
49{
50 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
51 info AR built-in.o
52 rm -f built-in.o;
53 ${AR} rcsT${KBUILD_ARFLAGS} built-in.o \
54 ${KBUILD_VMLINUX_INIT} \
55 ${KBUILD_VMLINUX_MAIN}
56 fi
57}
58
59# Link of vmlinux.o used for section mismatch analysis
60# ${1} output file
61modpost_link()
62{
63 local objects
64
65 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
66 objects="--whole-archive built-in.o"
67 else
68 objects="${KBUILD_VMLINUX_INIT} \
69 --start-group \
70 ${KBUILD_VMLINUX_MAIN} \
71 --end-group"
72 fi
73 ${LD} ${LDFLAGS} -r -o ${1} ${objects}
74}
75
76# Link of vmlinux
77# ${1} - optional extra .o files
78# ${2} - output file
79vmlinux_link()
80{
81 local lds="${objtree}/${KBUILD_LDS}"
82 local objects
83
84 if [ "${SRCARCH}" != "um" ]; then
85 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
86 objects="--whole-archive built-in.o ${1}"
87 else
88 objects="${KBUILD_VMLINUX_INIT} \
89 --start-group \
90 ${KBUILD_VMLINUX_MAIN} \
91 --end-group \
92 ${1}"
93 fi
94
95 ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
96 -T ${lds} ${objects}
97 else
98 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
99 objects="-Wl,--whole-archive built-in.o ${1}"
100 else
101 objects="${KBUILD_VMLINUX_INIT} \
102 -Wl,--start-group \
103 ${KBUILD_VMLINUX_MAIN} \
104 -Wl,--end-group \
105 ${1}"
106 fi
107
108 ${CC} ${CFLAGS_vmlinux} -o ${2} \
109 -Wl,-T,${lds} \
110 ${objects} \
111 -lutil -lrt -lpthread
112 rm -f linux
113 fi
114}
115
116
117# Create ${2} .o file with all symbols from the ${1} object file
118kallsyms()
119{
120 info KSYM ${2}
121 local kallsymopt;
122
123 if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
124 kallsymopt="${kallsymopt} --symbol-prefix=_"
125 fi
126
127 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
128 kallsymopt="${kallsymopt} --all-symbols"
129 fi
130
131 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
132 kallsymopt="${kallsymopt} --absolute-percpu"
133 fi
134
135 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
136 kallsymopt="${kallsymopt} --base-relative"
137 fi
138
139 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
140 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
141
142 local afile="`basename ${2} .o`.S"
143
144 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
145 ${CC} ${aflags} -c -o ${2} ${afile}
146}
147
148# Create map file with all symbols from ${1}
149# See mksymap for additional details
150mksysmap()
151{
152 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
153}
154
155sortextable()
156{
157 ${objtree}/scripts/sortextable ${1}
158}
159
160# Delete output files in case of error
161cleanup()
162{
163 rm -f .old_version
164 rm -f .tmp_System.map
165 rm -f .tmp_kallsyms*
166 rm -f .tmp_version
167 rm -f .tmp_vmlinux*
168 rm -f built-in.o
169 rm -f System.map
170 rm -f vmlinux
171 rm -f vmlinux.o
172}
173
174on_exit()
175{
176 if [ $? -ne 0 ]; then
177 cleanup
178 fi
179}
180trap on_exit EXIT
181
182on_signals()
183{
184 exit 1
185}
186trap on_signals HUP INT QUIT TERM
187
188#
189#
190# Use "make V=1" to debug this script
191case "${KBUILD_VERBOSE}" in
192*1*)
193 set -x
194 ;;
195esac
196
197if [ "$1" = "clean" ]; then
198 cleanup
199 exit 0
200fi
201
202# We need access to CONFIG_ symbols
203case "${KCONFIG_CONFIG}" in
204*/*)
205 . "${KCONFIG_CONFIG}"
206 ;;
207*)
208 # Force using a file from the current directory
209 . "./${KCONFIG_CONFIG}"
210esac
211
212# Update version
213info GEN .version
214if [ ! -r .version ]; then
215 rm -f .version;
216 echo 1 >.version;
217else
218 mv .version .old_version;
219 expr 0$(cat .old_version) + 1 >.version;
220fi;
221
222# final build of init/
223${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GCC_PLUGINS_CFLAGS}"
224
225archive_builtin
226
227#link vmlinux.o
228info LD vmlinux.o
229modpost_link vmlinux.o
230
231# modpost vmlinux.o to check for section mismatches
232${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
233
234kallsymso=""
235kallsyms_vmlinux=""
236if [ -n "${CONFIG_KALLSYMS}" ]; then
237
238 # kallsyms support
239 # Generate section listing all symbols and add it into vmlinux
240 # It's a three step process:
241 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
242 # but __kallsyms is empty.
243 # Running kallsyms on that gives us .tmp_kallsyms1.o with
244 # the right size
245 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
246 # the right size, but due to the added section, some
247 # addresses have shifted.
248 # From here, we generate a correct .tmp_kallsyms2.o
249 # 3) That link may have expanded the kernel image enough that
250 # more linker branch stubs / trampolines had to be added, which
251 # introduces new names, which further expands kallsyms. Do another
252 # pass if that is the case. In theory it's possible this results
253 # in even more stubs, but unlikely.
254 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
255 # other bugs.
256 # 4) The correct ${kallsymso} is linked into the final vmlinux.
257 #
258 # a) Verify that the System.map from vmlinux matches the map from
259 # ${kallsymso}.
260
261 kallsymso=.tmp_kallsyms2.o
262 kallsyms_vmlinux=.tmp_vmlinux2
263
264 # step 1
265 vmlinux_link "" .tmp_vmlinux1
266 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
267
268 # step 2
269 vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
270 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
271
272 # step 3
273 size1=$(stat -c "%s" .tmp_kallsyms1.o)
274 size2=$(stat -c "%s" .tmp_kallsyms2.o)
275
276 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
277 kallsymso=.tmp_kallsyms3.o
278 kallsyms_vmlinux=.tmp_vmlinux3
279
280 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
281
282 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
283 fi
284fi
285
286info LD vmlinux
287vmlinux_link "${kallsymso}" vmlinux
288
289if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
290 info SORTEX vmlinux
291 sortextable vmlinux
292fi
293
294info SYSMAP System.map
295mksysmap vmlinux System.map
296
297# step a (see comment above)
298if [ -n "${CONFIG_KALLSYMS}" ]; then
299 mksysmap ${kallsyms_vmlinux} .tmp_System.map
300
301 if ! cmp -s System.map .tmp_System.map; then
302 echo >&2 Inconsistent kallsyms data
303 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
304 exit 1
305 fi
306fi
307
308# We made a new kernel - delete old version file
309rm -f .old_version