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Andrew Scullb4b6d4a2019-01-02 15:54:55 +00001#!/bin/sh
2# SPDX-License-Identifier: GPL-2.0
3#
4# link vmlinux
5#
David Brazdil0f672f62019-12-10 10:32:29 +00006# 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.
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000011#
12# vmlinux
13# ^
14# |
David Brazdil0f672f62019-12-10 10:32:29 +000015# +--< $(KBUILD_VMLINUX_OBJS)
16# | +--< init/built-in.a drivers/built-in.a mm/built-in.a + more
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000017# |
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
Olivier Deprez157378f2022-04-04 15:47:50 +020033LD="$1"
34KBUILD_LDFLAGS="$2"
35LDFLAGS_vmlinux="$3"
36
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000037# Nice output in kbuild format
38# Will be supressed by "make -s"
39info()
40{
41 if [ "${quiet}" != "silent_" ]; then
David Brazdil0f672f62019-12-10 10:32:29 +000042 printf " %-7s %s\n" "${1}" "${2}"
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000043 fi
44}
45
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000046# Link of vmlinux.o used for section mismatch analysis
47# ${1} output file
48modpost_link()
49{
50 local objects
51
52 objects="--whole-archive \
David Brazdil0f672f62019-12-10 10:32:29 +000053 ${KBUILD_VMLINUX_OBJS} \
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000054 --no-whole-archive \
55 --start-group \
56 ${KBUILD_VMLINUX_LIBS} \
57 --end-group"
58
59 ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
60}
61
Olivier Deprez157378f2022-04-04 15:47:50 +020062objtool_link()
63{
64 local objtoolopt;
65
66 if [ -n "${CONFIG_VMLINUX_VALIDATION}" ]; then
67 objtoolopt="check"
Olivier Deprez92d4c212022-12-06 15:05:30 +010068 if [ -n "${CONFIG_CPU_UNRET_ENTRY}" ]; then
69 objtoolopt="${objtoolopt} --unret"
70 fi
Olivier Deprez157378f2022-04-04 15:47:50 +020071 if [ -z "${CONFIG_FRAME_POINTER}" ]; then
72 objtoolopt="${objtoolopt} --no-fp"
73 fi
74 if [ -n "${CONFIG_GCOV_KERNEL}" ]; then
75 objtoolopt="${objtoolopt} --no-unreachable"
76 fi
77 if [ -n "${CONFIG_RETPOLINE}" ]; then
78 objtoolopt="${objtoolopt} --retpoline"
79 fi
80 if [ -n "${CONFIG_X86_SMAP}" ]; then
81 objtoolopt="${objtoolopt} --uaccess"
82 fi
Olivier Deprez92d4c212022-12-06 15:05:30 +010083 if [ -n "${CONFIG_SLS}" ]; then
84 objtoolopt="${objtoolopt} --sls"
85 fi
Olivier Deprez157378f2022-04-04 15:47:50 +020086 info OBJTOOL ${1}
87 tools/objtool/objtool ${objtoolopt} ${1}
88 fi
89}
90
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000091# Link of vmlinux
David Brazdil0f672f62019-12-10 10:32:29 +000092# ${1} - output file
93# ${2}, ${3}, ... - optional extra .o files
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000094vmlinux_link()
95{
96 local lds="${objtree}/${KBUILD_LDS}"
David Brazdil0f672f62019-12-10 10:32:29 +000097 local output=${1}
Andrew Scullb4b6d4a2019-01-02 15:54:55 +000098 local objects
Olivier Deprez0e641232021-09-23 10:07:05 +020099 local strip_debug
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000100
David Brazdil0f672f62019-12-10 10:32:29 +0000101 info LD ${output}
102
103 # skip output file argument
104 shift
105
Olivier Deprez0e641232021-09-23 10:07:05 +0200106 # The kallsyms linking does not need debug symbols included.
107 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
108 strip_debug=-Wl,--strip-debug
109 fi
110
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000111 if [ "${SRCARCH}" != "um" ]; then
112 objects="--whole-archive \
David Brazdil0f672f62019-12-10 10:32:29 +0000113 ${KBUILD_VMLINUX_OBJS} \
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000114 --no-whole-archive \
115 --start-group \
116 ${KBUILD_VMLINUX_LIBS} \
117 --end-group \
David Brazdil0f672f62019-12-10 10:32:29 +0000118 ${@}"
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000119
David Brazdil0f672f62019-12-10 10:32:29 +0000120 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
Olivier Deprez0e641232021-09-23 10:07:05 +0200121 ${strip_debug#-Wl,} \
David Brazdil0f672f62019-12-10 10:32:29 +0000122 -o ${output} \
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000123 -T ${lds} ${objects}
124 else
125 objects="-Wl,--whole-archive \
David Brazdil0f672f62019-12-10 10:32:29 +0000126 ${KBUILD_VMLINUX_OBJS} \
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000127 -Wl,--no-whole-archive \
128 -Wl,--start-group \
129 ${KBUILD_VMLINUX_LIBS} \
130 -Wl,--end-group \
David Brazdil0f672f62019-12-10 10:32:29 +0000131 ${@}"
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000132
David Brazdil0f672f62019-12-10 10:32:29 +0000133 ${CC} ${CFLAGS_vmlinux} \
Olivier Deprez0e641232021-09-23 10:07:05 +0200134 ${strip_debug} \
David Brazdil0f672f62019-12-10 10:32:29 +0000135 -o ${output} \
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000136 -Wl,-T,${lds} \
137 ${objects} \
138 -lutil -lrt -lpthread
139 rm -f linux
140 fi
141}
142
David Brazdil0f672f62019-12-10 10:32:29 +0000143# generate .BTF typeinfo from DWARF debuginfo
144# ${1} - vmlinux image
145# ${2} - file to dump raw BTF data into
146gen_btf()
147{
148 local pahole_ver
David Brazdil0f672f62019-12-10 10:32:29 +0000149
150 if ! [ -x "$(command -v ${PAHOLE})" ]; then
Olivier Deprez0e641232021-09-23 10:07:05 +0200151 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
David Brazdil0f672f62019-12-10 10:32:29 +0000152 return 1
153 fi
154
155 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
Olivier Deprez157378f2022-04-04 15:47:50 +0200156 if [ "${pahole_ver}" -lt "116" ]; then
157 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
David Brazdil0f672f62019-12-10 10:32:29 +0000158 return 1
159 fi
160
David Brazdil0f672f62019-12-10 10:32:29 +0000161 vmlinux_link ${1}
Olivier Deprez0e641232021-09-23 10:07:05 +0200162
163 info "BTF" ${2}
Olivier Deprez92d4c212022-12-06 15:05:30 +0100164 LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
David Brazdil0f672f62019-12-10 10:32:29 +0000165
Olivier Deprez0e641232021-09-23 10:07:05 +0200166 # Create ${2} which contains just .BTF section but no symbols. Add
167 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
168 # deletes all symbols including __start_BTF and __stop_BTF, which will
169 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
170 # objcopy warnings: "empty loadable segment detected at ..."
171 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
172 --strip-all ${1} ${2} 2>/dev/null
173 # Change e_type to ET_REL so that it can be used to link final vmlinux.
174 # Unlike GNU ld, lld does not allow an ET_EXEC input.
175 printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none
David Brazdil0f672f62019-12-10 10:32:29 +0000176}
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000177
Olivier Deprez157378f2022-04-04 15:47:50 +0200178# Create ${2} .S file with all symbols from the ${1} object file
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000179kallsyms()
180{
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000181 local kallsymopt;
182
183 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
184 kallsymopt="${kallsymopt} --all-symbols"
185 fi
186
187 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
188 kallsymopt="${kallsymopt} --absolute-percpu"
189 fi
190
191 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
192 kallsymopt="${kallsymopt} --base-relative"
193 fi
194
Olivier Deprez157378f2022-04-04 15:47:50 +0200195 info KSYMS ${2}
196 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${2}
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000197}
198
David Brazdil0f672f62019-12-10 10:32:29 +0000199# Perform one step in kallsyms generation, including temporary linking of
200# vmlinux.
201kallsyms_step()
202{
203 kallsymso_prev=${kallsymso}
Olivier Deprez0e641232021-09-23 10:07:05 +0200204 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
205 kallsymso=${kallsyms_vmlinux}.o
Olivier Deprez157378f2022-04-04 15:47:50 +0200206 kallsyms_S=${kallsyms_vmlinux}.S
David Brazdil0f672f62019-12-10 10:32:29 +0000207
208 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
Olivier Deprez157378f2022-04-04 15:47:50 +0200209 kallsyms ${kallsyms_vmlinux} ${kallsyms_S}
210
211 info AS ${kallsyms_S}
212 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
213 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
214 -c -o ${kallsymso} ${kallsyms_S}
David Brazdil0f672f62019-12-10 10:32:29 +0000215}
216
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000217# Create map file with all symbols from ${1}
218# See mksymap for additional details
219mksysmap()
220{
221 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
222}
223
Olivier Deprez157378f2022-04-04 15:47:50 +0200224sorttable()
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000225{
Olivier Deprez157378f2022-04-04 15:47:50 +0200226 ${objtree}/scripts/sorttable ${1}
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000227}
228
229# Delete output files in case of error
230cleanup()
231{
David Brazdil0f672f62019-12-10 10:32:29 +0000232 rm -f .btf.*
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000233 rm -f .tmp_System.map
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000234 rm -f .tmp_vmlinux*
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000235 rm -f System.map
236 rm -f vmlinux
237 rm -f vmlinux.o
238}
239
240on_exit()
241{
242 if [ $? -ne 0 ]; then
243 cleanup
244 fi
245}
246trap on_exit EXIT
247
248on_signals()
249{
250 exit 1
251}
252trap on_signals HUP INT QUIT TERM
253
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000254# Use "make V=1" to debug this script
255case "${KBUILD_VERBOSE}" in
256*1*)
257 set -x
258 ;;
259esac
260
261if [ "$1" = "clean" ]; then
262 cleanup
263 exit 0
264fi
265
266# We need access to CONFIG_ symbols
David Brazdil0f672f62019-12-10 10:32:29 +0000267. include/config/auto.conf
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000268
269# Update version
270info GEN .version
271if [ -r .version ]; then
272 VERSION=$(expr 0$(cat .version) + 1)
273 echo $VERSION > .version
274else
275 rm -f .version
276 echo 1 > .version
277fi;
278
279# final build of init/
Olivier Deprez157378f2022-04-04 15:47:50 +0200280${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000281
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000282#link vmlinux.o
283info LD vmlinux.o
284modpost_link vmlinux.o
Olivier Deprez157378f2022-04-04 15:47:50 +0200285objtool_link vmlinux.o
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000286
287# modpost vmlinux.o to check for section mismatches
David Brazdil0f672f62019-12-10 10:32:29 +0000288${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
289
290info MODINFO modules.builtin.modinfo
291${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
Olivier Deprez157378f2022-04-04 15:47:50 +0200292info GEN modules.builtin
293# The second line aids cases where multiple modules share the same object.
294tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
295 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
David Brazdil0f672f62019-12-10 10:32:29 +0000296
297btf_vmlinux_bin_o=""
298if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
Olivier Deprez0e641232021-09-23 10:07:05 +0200299 btf_vmlinux_bin_o=.btf.vmlinux.bin.o
300 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
301 echo >&2 "Failed to generate BTF for vmlinux"
302 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
303 exit 1
David Brazdil0f672f62019-12-10 10:32:29 +0000304 fi
305fi
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000306
307kallsymso=""
David Brazdil0f672f62019-12-10 10:32:29 +0000308kallsymso_prev=""
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000309kallsyms_vmlinux=""
310if [ -n "${CONFIG_KALLSYMS}" ]; then
311
312 # kallsyms support
313 # Generate section listing all symbols and add it into vmlinux
314 # It's a three step process:
315 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
316 # but __kallsyms is empty.
317 # Running kallsyms on that gives us .tmp_kallsyms1.o with
318 # the right size
319 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
320 # the right size, but due to the added section, some
321 # addresses have shifted.
322 # From here, we generate a correct .tmp_kallsyms2.o
323 # 3) That link may have expanded the kernel image enough that
324 # more linker branch stubs / trampolines had to be added, which
325 # introduces new names, which further expands kallsyms. Do another
326 # pass if that is the case. In theory it's possible this results
327 # in even more stubs, but unlikely.
328 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
329 # other bugs.
330 # 4) The correct ${kallsymso} is linked into the final vmlinux.
331 #
332 # a) Verify that the System.map from vmlinux matches the map from
333 # ${kallsymso}.
334
David Brazdil0f672f62019-12-10 10:32:29 +0000335 kallsyms_step 1
336 kallsyms_step 2
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000337
338 # step 3
David Brazdil0f672f62019-12-10 10:32:29 +0000339 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
340 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000341
342 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
David Brazdil0f672f62019-12-10 10:32:29 +0000343 kallsyms_step 3
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000344 fi
345fi
346
David Brazdil0f672f62019-12-10 10:32:29 +0000347vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000348
Olivier Deprez157378f2022-04-04 15:47:50 +0200349# fill in BTF IDs
350if [ -n "${CONFIG_DEBUG_INFO_BTF}" -a -n "${CONFIG_BPF}" ]; then
351 info BTFIDS vmlinux
352 ${RESOLVE_BTFIDS} vmlinux
353fi
354
355if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
356 info SORTTAB vmlinux
357 if ! sorttable vmlinux; then
358 echo >&2 Failed to sort kernel tables
359 exit 1
360 fi
Andrew Scullb4b6d4a2019-01-02 15:54:55 +0000361fi
362
363info SYSMAP System.map
364mksysmap vmlinux System.map
365
366# step a (see comment above)
367if [ -n "${CONFIG_KALLSYMS}" ]; then
368 mksysmap ${kallsyms_vmlinux} .tmp_System.map
369
370 if ! cmp -s System.map .tmp_System.map; then
371 echo >&2 Inconsistent kallsyms data
372 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
373 exit 1
374 fi
375fi