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