projects/linux·blob v5.7 · refs

337 lines · 8.4 KiB

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 local strip_debug
67
68 info LD ${output}
69
70 # skip output file argument
71 shift
72
73 # The kallsyms linking does not need debug symbols included.
74 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
75 strip_debug=-Wl,--strip-debug
76 fi
77
78 if [ "${SRCARCH}" != "um" ]; then
79 objects="--whole-archive \
80 ${KBUILD_VMLINUX_OBJS} \
81 --no-whole-archive \
82 --start-group \
83 ${KBUILD_VMLINUX_LIBS} \
84 --end-group \
85 ${@}"
86
87 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
88 ${strip_debug#-Wl,} \
89 -o ${output} \
90 -T ${lds} ${objects}
91 else
92 objects="-Wl,--whole-archive \
93 ${KBUILD_VMLINUX_OBJS} \
94 -Wl,--no-whole-archive \
95 -Wl,--start-group \
96 ${KBUILD_VMLINUX_LIBS} \
97 -Wl,--end-group \
98 ${@}"
99
100 ${CC} ${CFLAGS_vmlinux} \
101 ${strip_debug} \
102 -o ${output} \
103 -Wl,-T,${lds} \
104 ${objects} \
105 -lutil -lrt -lpthread
106 rm -f linux
107 fi
108}
109
110# generate .BTF typeinfo from DWARF debuginfo
111# ${1} - vmlinux image
112# ${2} - file to dump raw BTF data into
113gen_btf()
114{
115 local pahole_ver
116
117 if ! [ -x "$(command -v ${PAHOLE})" ]; then
118 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
119 return 1
120 fi
121
122 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
123 if [ "${pahole_ver}" -lt "113" ]; then
124 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
125 return 1
126 fi
127
128 vmlinux_link ${1}
129
130 info "BTF" ${2}
131 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
132
133 # Create ${2} which contains just .BTF section but no symbols. Add
134 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
135 # deletes all symbols including __start_BTF and __stop_BTF, which will
136 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
137 # objcopy warnings: "empty loadable segment detected at ..."
138 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
139 --strip-all ${1} ${2} 2>/dev/null
140 # Change e_type to ET_REL so that it can be used to link final vmlinux.
141 # Unlike GNU ld, lld does not allow an ET_EXEC input.
142 printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 status=none
143}
144
145# Create ${2} .o file with all symbols from the ${1} object file
146kallsyms()
147{
148 info KSYM ${2}
149 local kallsymopt;
150
151 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
152 kallsymopt="${kallsymopt} --all-symbols"
153 fi
154
155 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
156 kallsymopt="${kallsymopt} --absolute-percpu"
157 fi
158
159 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
160 kallsymopt="${kallsymopt} --base-relative"
161 fi
162
163 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
164 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
165
166 local afile="`basename ${2} .o`.S"
167
168 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
169 ${CC} ${aflags} -c -o ${2} ${afile}
170}
171
172# Perform one step in kallsyms generation, including temporary linking of
173# vmlinux.
174kallsyms_step()
175{
176 kallsymso_prev=${kallsymso}
177 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
178 kallsymso=${kallsyms_vmlinux}.o
179
180 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
181 kallsyms ${kallsyms_vmlinux} ${kallsymso}
182}
183
184# Create map file with all symbols from ${1}
185# See mksymap for additional details
186mksysmap()
187{
188 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
189}
190
191sorttable()
192{
193 ${objtree}/scripts/sorttable ${1}
194}
195
196# Delete output files in case of error
197cleanup()
198{
199 rm -f .btf.*
200 rm -f .tmp_System.map
201 rm -f .tmp_vmlinux*
202 rm -f System.map
203 rm -f vmlinux
204 rm -f vmlinux.o
205}
206
207on_exit()
208{
209 if [ $? -ne 0 ]; then
210 cleanup
211 fi
212}
213trap on_exit EXIT
214
215on_signals()
216{
217 exit 1
218}
219trap on_signals HUP INT QUIT TERM
220
221#
222#
223# Use "make V=1" to debug this script
224case "${KBUILD_VERBOSE}" in
225*1*)
226 set -x
227 ;;
228esac
229
230if [ "$1" = "clean" ]; then
231 cleanup
232 exit 0
233fi
234
235# We need access to CONFIG_ symbols
236. include/config/auto.conf
237
238# Update version
239info GEN .version
240if [ -r .version ]; then
241 VERSION=$(expr 0$(cat .version) + 1)
242 echo $VERSION > .version
243else
244 rm -f .version
245 echo 1 > .version
246fi;
247
248# final build of init/
249${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
250
251#link vmlinux.o
252info LD vmlinux.o
253modpost_link vmlinux.o
254
255# modpost vmlinux.o to check for section mismatches
256${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
257
258info MODINFO modules.builtin.modinfo
259${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
260info GEN modules.builtin
261# The second line aids cases where multiple modules share the same object.
262tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
263 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
264
265btf_vmlinux_bin_o=""
266if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
267 btf_vmlinux_bin_o=.btf.vmlinux.bin.o
268 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
269 echo >&2 "Failed to generate BTF for vmlinux"
270 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
271 exit 1
272 fi
273fi
274
275kallsymso=""
276kallsymso_prev=""
277kallsyms_vmlinux=""
278if [ -n "${CONFIG_KALLSYMS}" ]; then
279
280 # kallsyms support
281 # Generate section listing all symbols and add it into vmlinux
282 # It's a three step process:
283 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
284 # but __kallsyms is empty.
285 # Running kallsyms on that gives us .tmp_kallsyms1.o with
286 # the right size
287 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
288 # the right size, but due to the added section, some
289 # addresses have shifted.
290 # From here, we generate a correct .tmp_kallsyms2.o
291 # 3) That link may have expanded the kernel image enough that
292 # more linker branch stubs / trampolines had to be added, which
293 # introduces new names, which further expands kallsyms. Do another
294 # pass if that is the case. In theory it's possible this results
295 # in even more stubs, but unlikely.
296 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
297 # other bugs.
298 # 4) The correct ${kallsymso} is linked into the final vmlinux.
299 #
300 # a) Verify that the System.map from vmlinux matches the map from
301 # ${kallsymso}.
302
303 kallsyms_step 1
304 kallsyms_step 2
305
306 # step 3
307 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
308 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
309
310 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
311 kallsyms_step 3
312 fi
313fi
314
315vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
316
317if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
318 info SORTTAB vmlinux
319 if ! sorttable vmlinux; then
320 echo >&2 Failed to sort kernel tables
321 exit 1
322 fi
323fi
324
325info SYSMAP System.map
326mksysmap vmlinux System.map
327
328# step a (see comment above)
329if [ -n "${CONFIG_KALLSYMS}" ]; then
330 mksysmap ${kallsyms_vmlinux} .tmp_System.map
331
332 if ! cmp -s System.map .tmp_System.map; then
333 echo >&2 Inconsistent kallsyms data
334 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
335 exit 1
336 fi
337fi