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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# Link of vmlinux.o used for section mismatch analysis
41# ${1} output file
42modpost_link()
43{
44 ${LD} ${LDFLAGS} -r -o ${1} ${KBUILD_VMLINUX_INIT} \
45 --start-group ${KBUILD_VMLINUX_MAIN} --end-group
46}
47
48# Link of vmlinux
49# ${1} - optional extra .o files
50# ${2} - output file
51vmlinux_link()
52{
53 local lds="${objtree}/${KBUILD_LDS}"
54
55 if [ "${SRCARCH}" != "um" ]; then
56 ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2} \
57 -T ${lds} ${KBUILD_VMLINUX_INIT} \
58 --start-group ${KBUILD_VMLINUX_MAIN} --end-group ${1}
59 else
60 ${CC} ${CFLAGS_vmlinux} -o ${2} \
61 -Wl,-T,${lds} ${KBUILD_VMLINUX_INIT} \
62 -Wl,--start-group \
63 ${KBUILD_VMLINUX_MAIN} \
64 -Wl,--end-group \
65 -lutil ${1}
66 rm -f linux
67 fi
68}
69
70
71# Create ${2} .o file with all symbols from the ${1} object file
72kallsyms()
73{
74 info KSYM ${2}
75 local kallsymopt;
76
77 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
78 kallsymopt=--all-symbols
79 fi
80
81 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
82 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
83
84 ${NM} -n ${1} | \
85 scripts/kallsyms ${kallsymopt} | \
86 ${CC} ${aflags} -c -o ${2} -x assembler-with-cpp -
87}
88
89# Create map file with all symbols from ${1}
90# See mksymap for additional details
91mksysmap()
92{
93 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
94}
95
96sortextable()
97{
98 ${objtree}/scripts/sortextable ${1}
99}
100
101# Delete output files in case of error
102trap cleanup SIGHUP SIGINT SIGQUIT SIGTERM ERR
103cleanup()
104{
105 rm -f .old_version
106 rm -f .tmp_System.map
107 rm -f .tmp_kallsyms*
108 rm -f .tmp_version
109 rm -f .tmp_vmlinux*
110 rm -f System.map
111 rm -f vmlinux
112 rm -f vmlinux.o
113}
114
115#
116#
117# Use "make V=1" to debug this script
118case "${KBUILD_VERBOSE}" in
119*1*)
120 set -x
121 ;;
122esac
123
124if [ "$1" = "clean" ]; then
125 cleanup
126 exit 0
127fi
128
129# We need access to CONFIG_ symbols
130. ./.config
131
132#link vmlinux.o
133info LD vmlinux.o
134modpost_link vmlinux.o
135
136# modpost vmlinux.o to check for section mismatches
137${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
138
139# Update version
140info GEN .version
141if [ ! -r .version ]; then
142 rm -f .version;
143 echo 1 >.version;
144else
145 mv .version .old_version;
146 expr 0$(cat .old_version) + 1 >.version;
147fi;
148
149# final build of init/
150${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
151
152kallsymso=""
153kallsyms_vmlinux=""
154if [ -n "${CONFIG_KALLSYMS}" ]; then
155
156 # kallsyms support
157 # Generate section listing all symbols and add it into vmlinux
158 # It's a three step process:
159 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
160 # but __kallsyms is empty.
161 # Running kallsyms on that gives us .tmp_kallsyms1.o with
162 # the right size
163 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
164 # the right size, but due to the added section, some
165 # addresses have shifted.
166 # From here, we generate a correct .tmp_kallsyms2.o
167 # 2a) We may use an extra pass as this has been necessary to
168 # woraround some alignment related bugs.
169 # KALLSYMS_EXTRA_PASS=1 is used to trigger this.
170 # 3) The correct ${kallsymso} is linked into the final vmlinux.
171 #
172 # a) Verify that the System.map from vmlinux matches the map from
173 # ${kallsymso}.
174
175 kallsymso=.tmp_kallsyms2.o
176 kallsyms_vmlinux=.tmp_vmlinux2
177
178 # step 1
179 vmlinux_link "" .tmp_vmlinux1
180 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
181
182 # step 2
183 vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
184 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
185
186 # step 2a
187 if [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
188 kallsymso=.tmp_kallsyms3.o
189 kallsyms_vmlinux=.tmp_vmlinux3
190
191 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
192
193 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
194 fi
195fi
196
197info LD vmlinux
198vmlinux_link "${kallsymso}" vmlinux
199
200if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
201 info SORTEX vmlinux
202 sortextable vmlinux
203fi
204
205info SYSMAP System.map
206mksysmap vmlinux System.map
207
208# step a (see comment above)
209if [ -n "${CONFIG_KALLSYMS}" ]; then
210 mksysmap ${kallsyms_vmlinux} .tmp_System.map
211
212 if ! cmp -s System.map .tmp_System.map; then
213 echo Inconsistent kallsyms data
214 echo echo Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
215 cleanup
216 exit 1
217 fi
218fi
219
220# We made a new kernel - delete old version file
221rm -f .old_version
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="$3"
36
37# Nice output in kbuild format
38# Will be supressed by "make -s"
39info()
40{
41 printf " %-7s %s\n" "${1}" "${2}"
42}
43
44# Generate a linker script to ensure correct ordering of initcalls.
45gen_initcalls()
46{
47 info GEN .tmp_initcalls.lds
48
49 ${PYTHON} ${srctree}/scripts/jobserver-exec \
50 ${PERL} ${srctree}/scripts/generate_initcall_order.pl \
51 ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS} \
52 > .tmp_initcalls.lds
53}
54
55# If CONFIG_LTO_CLANG is selected, collect generated symbol versions into
56# .tmp_symversions.lds
57gen_symversions()
58{
59 info GEN .tmp_symversions.lds
60 rm -f .tmp_symversions.lds
61
62 for o in ${KBUILD_VMLINUX_OBJS} ${KBUILD_VMLINUX_LIBS}; do
63 if [ -f ${o}.symversions ]; then
64 cat ${o}.symversions >> .tmp_symversions.lds
65 fi
66 done
67}
68
69# Link of vmlinux.o used for section mismatch analysis
70# ${1} output file
71modpost_link()
72{
73 local objects
74 local lds=""
75
76 objects="--whole-archive \
77 ${KBUILD_VMLINUX_OBJS} \
78 --no-whole-archive \
79 --start-group \
80 ${KBUILD_VMLINUX_LIBS} \
81 --end-group"
82
83 if [ -n "${CONFIG_LTO_CLANG}" ]; then
84 gen_initcalls
85 lds="-T .tmp_initcalls.lds"
86
87 if [ -n "${CONFIG_MODVERSIONS}" ]; then
88 gen_symversions
89 lds="${lds} -T .tmp_symversions.lds"
90 fi
91
92 # This might take a while, so indicate that we're doing
93 # an LTO link
94 info LTO ${1}
95 else
96 info LD ${1}
97 fi
98
99 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${lds} ${objects}
100}
101
102objtool_link()
103{
104 local objtoolcmd;
105 local objtoolopt;
106
107 if [ "${CONFIG_LTO_CLANG} ${CONFIG_STACK_VALIDATION}" = "y y" ]; then
108 # Don't perform vmlinux validation unless explicitly requested,
109 # but run objtool on vmlinux.o now that we have an object file.
110 if [ -n "${CONFIG_UNWINDER_ORC}" ]; then
111 objtoolcmd="orc generate"
112 fi
113
114 objtoolopt="${objtoolopt} --duplicate"
115
116 if [ -n "${CONFIG_FTRACE_MCOUNT_USE_OBJTOOL}" ]; then
117 objtoolopt="${objtoolopt} --mcount"
118 fi
119 fi
120
121 if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
122 objtoolopt="${objtoolopt} --noinstr"
123 fi
124
125 if [ -n "${objtoolopt}" ]; then
126 if [ -z "${objtoolcmd}" ]; then
127 objtoolcmd="check"
128 fi
129 objtoolopt="${objtoolopt} --vmlinux"
130 if [ -z "${CONFIG_FRAME_POINTER}" ]; then
131 objtoolopt="${objtoolopt} --no-fp"
132 fi
133 if [ -n "${CONFIG_GCOV_KERNEL}" ] || [ -n "${CONFIG_LTO_CLANG}" ]; then
134 objtoolopt="${objtoolopt} --no-unreachable"
135 fi
136 if [ -n "${CONFIG_RETPOLINE}" ]; then
137 objtoolopt="${objtoolopt} --retpoline"
138 fi
139 if [ -n "${CONFIG_X86_SMAP}" ]; then
140 objtoolopt="${objtoolopt} --uaccess"
141 fi
142 info OBJTOOL ${1}
143 tools/objtool/objtool ${objtoolcmd} ${objtoolopt} ${1}
144 fi
145}
146
147# Link of vmlinux
148# ${1} - output file
149# ${2}, ${3}, ... - optional extra .o files
150vmlinux_link()
151{
152 local lds="${objtree}/${KBUILD_LDS}"
153 local output=${1}
154 local objects
155 local strip_debug
156 local map_option
157
158 info LD ${output}
159
160 # skip output file argument
161 shift
162
163 # The kallsyms linking does not need debug symbols included.
164 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
165 strip_debug=-Wl,--strip-debug
166 fi
167
168 if [ -n "${CONFIG_VMLINUX_MAP}" ]; then
169 map_option="-Map=${output}.map"
170 fi
171
172 if [ "${SRCARCH}" != "um" ]; then
173 if [ -n "${CONFIG_LTO_CLANG}" ]; then
174 # Use vmlinux.o instead of performing the slow LTO
175 # link again.
176 objects="--whole-archive \
177 vmlinux.o \
178 --no-whole-archive \
179 ${@}"
180 else
181 objects="--whole-archive \
182 ${KBUILD_VMLINUX_OBJS} \
183 --no-whole-archive \
184 --start-group \
185 ${KBUILD_VMLINUX_LIBS} \
186 --end-group \
187 ${@}"
188 fi
189
190 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
191 ${strip_debug#-Wl,} \
192 -o ${output} \
193 ${map_option} \
194 -T ${lds} ${objects}
195 else
196 objects="-Wl,--whole-archive \
197 ${KBUILD_VMLINUX_OBJS} \
198 -Wl,--no-whole-archive \
199 -Wl,--start-group \
200 ${KBUILD_VMLINUX_LIBS} \
201 -Wl,--end-group \
202 ${@}"
203
204 ${CC} ${CFLAGS_vmlinux} \
205 ${strip_debug} \
206 -o ${output} \
207 ${map_option:+-Wl,${map_option}} \
208 -Wl,-T,${lds} \
209 ${objects} \
210 -lutil -lrt -lpthread
211 rm -f linux
212 fi
213}
214
215# generate .BTF typeinfo from DWARF debuginfo
216# ${1} - vmlinux image
217# ${2} - file to dump raw BTF data into
218gen_btf()
219{
220 local pahole_ver
221 local extra_paholeopt=
222
223 if ! [ -x "$(command -v ${PAHOLE})" ]; then
224 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
225 return 1
226 fi
227
228 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
229 if [ "${pahole_ver}" -lt "116" ]; then
230 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
231 return 1
232 fi
233
234 vmlinux_link ${1}
235
236 if [ "${pahole_ver}" -ge "118" ] && [ "${pahole_ver}" -le "121" ]; then
237 # pahole 1.18 through 1.21 can't handle zero-sized per-CPU vars
238 extra_paholeopt="${extra_paholeopt} --skip_encoding_btf_vars"
239 fi
240 if [ "${pahole_ver}" -ge "121" ]; then
241 extra_paholeopt="${extra_paholeopt} --btf_gen_floats"
242 fi
243
244 info "BTF" ${2}
245 LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${extra_paholeopt} ${1}
246
247 # Create ${2} which contains just .BTF section but no symbols. Add
248 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
249 # deletes all symbols including __start_BTF and __stop_BTF, which will
250 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
251 # objcopy warnings: "empty loadable segment detected at ..."
252 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
253 --strip-all ${1} ${2} 2>/dev/null
254 # Change e_type to ET_REL so that it can be used to link final vmlinux.
255 # Unlike GNU ld, lld does not allow an ET_EXEC input.
256 printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none
257}
258
259# Create ${2} .S file with all symbols from the ${1} object file
260kallsyms()
261{
262 local kallsymopt;
263
264 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
265 kallsymopt="${kallsymopt} --all-symbols"
266 fi
267
268 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
269 kallsymopt="${kallsymopt} --absolute-percpu"
270 fi
271
272 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
273 kallsymopt="${kallsymopt} --base-relative"
274 fi
275
276 info KSYMS ${2}
277 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2}
278}
279
280# Perform one step in kallsyms generation, including temporary linking of
281# vmlinux.
282kallsyms_step()
283{
284 kallsymso_prev=${kallsymso}
285 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
286 kallsymso=${kallsyms_vmlinux}.o
287 kallsyms_S=${kallsyms_vmlinux}.S
288
289 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
290 kallsyms ${kallsyms_vmlinux} ${kallsyms_S}
291
292 info AS ${kallsyms_S}
293 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
294 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
295 -c -o ${kallsymso} ${kallsyms_S}
296}
297
298# Create map file with all symbols from ${1}
299# See mksymap for additional details
300mksysmap()
301{
302 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
303}
304
305sorttable()
306{
307 ${objtree}/scripts/sorttable ${1}
308}
309
310# Delete output files in case of error
311cleanup()
312{
313 rm -f .btf.*
314 rm -f .tmp_System.map
315 rm -f .tmp_initcalls.lds
316 rm -f .tmp_symversions.lds
317 rm -f .tmp_vmlinux*
318 rm -f System.map
319 rm -f vmlinux
320 rm -f vmlinux.map
321 rm -f vmlinux.o
322 rm -f .vmlinux.d
323}
324
325# Use "make V=1" to debug this script
326case "${KBUILD_VERBOSE}" in
327*1*)
328 set -x
329 ;;
330esac
331
332if [ "$1" = "clean" ]; then
333 cleanup
334 exit 0
335fi
336
337# We need access to CONFIG_ symbols
338. include/config/auto.conf
339
340# Update version
341info GEN .version
342if [ -r .version ]; then
343 VERSION=$(expr 0$(cat .version) + 1)
344 echo $VERSION > .version
345else
346 rm -f .version
347 echo 1 > .version
348fi;
349
350# final build of init/
351${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
352
353#link vmlinux.o
354modpost_link vmlinux.o
355objtool_link vmlinux.o
356
357# modpost vmlinux.o to check for section mismatches
358${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
359
360info MODINFO modules.builtin.modinfo
361${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
362info GEN modules.builtin
363# The second line aids cases where multiple modules share the same object.
364tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
365 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
366
367btf_vmlinux_bin_o=""
368if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
369 btf_vmlinux_bin_o=.btf.vmlinux.bin.o
370 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
371 echo >&2 "Failed to generate BTF for vmlinux"
372 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
373 exit 1
374 fi
375fi
376
377kallsymso=""
378kallsymso_prev=""
379kallsyms_vmlinux=""
380if [ -n "${CONFIG_KALLSYMS}" ]; then
381
382 # kallsyms support
383 # Generate section listing all symbols and add it into vmlinux
384 # It's a three step process:
385 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
386 # but __kallsyms is empty.
387 # Running kallsyms on that gives us .tmp_kallsyms1.o with
388 # the right size
389 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
390 # the right size, but due to the added section, some
391 # addresses have shifted.
392 # From here, we generate a correct .tmp_kallsyms2.o
393 # 3) That link may have expanded the kernel image enough that
394 # more linker branch stubs / trampolines had to be added, which
395 # introduces new names, which further expands kallsyms. Do another
396 # pass if that is the case. In theory it's possible this results
397 # in even more stubs, but unlikely.
398 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
399 # other bugs.
400 # 4) The correct ${kallsymso} is linked into the final vmlinux.
401 #
402 # a) Verify that the System.map from vmlinux matches the map from
403 # ${kallsymso}.
404
405 kallsyms_step 1
406 kallsyms_step 2
407
408 # step 3
409 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
410 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
411
412 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
413 kallsyms_step 3
414 fi
415fi
416
417vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
418
419# fill in BTF IDs
420if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then
421 info BTFIDS vmlinux
422 ${RESOLVE_BTFIDS} vmlinux
423fi
424
425if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
426 info SORTTAB vmlinux
427 if ! sorttable vmlinux; then
428 echo >&2 Failed to sort kernel tables
429 exit 1
430 fi
431fi
432
433info SYSMAP System.map
434mksysmap vmlinux System.map
435
436# step a (see comment above)
437if [ -n "${CONFIG_KALLSYMS}" ]; then
438 mksysmap ${kallsyms_vmlinux} .tmp_System.map
439
440 if ! cmp -s System.map .tmp_System.map; then
441 echo >&2 Inconsistent kallsyms data
442 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
443 exit 1
444 fi
445fi
446
447# For fixdep
448echo "vmlinux: $0" > .vmlinux.d