projects/linux·blob v5.6 · refs

331 lines · 8.0 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
67 info LD ${output}
68
69 # skip output file argument
70 shift
71
72 if [ "${SRCARCH}" != "um" ]; then
73 objects="--whole-archive \
74 ${KBUILD_VMLINUX_OBJS} \
75 --no-whole-archive \
76 --start-group \
77 ${KBUILD_VMLINUX_LIBS} \
78 --end-group \
79 ${@}"
80
81 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} \
82 -o ${output} \
83 -T ${lds} ${objects}
84 else
85 objects="-Wl,--whole-archive \
86 ${KBUILD_VMLINUX_OBJS} \
87 -Wl,--no-whole-archive \
88 -Wl,--start-group \
89 ${KBUILD_VMLINUX_LIBS} \
90 -Wl,--end-group \
91 ${@}"
92
93 ${CC} ${CFLAGS_vmlinux} \
94 -o ${output} \
95 -Wl,-T,${lds} \
96 ${objects} \
97 -lutil -lrt -lpthread
98 rm -f linux
99 fi
100}
101
102# generate .BTF typeinfo from DWARF debuginfo
103# ${1} - vmlinux image
104# ${2} - file to dump raw BTF data into
105gen_btf()
106{
107 local pahole_ver
108 local bin_arch
109
110 if ! [ -x "$(command -v ${PAHOLE})" ]; then
111 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
112 return 1
113 fi
114
115 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
116 if [ "${pahole_ver}" -lt "113" ]; then
117 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
118 return 1
119 fi
120
121 info "BTF" ${2}
122 vmlinux_link ${1}
123 LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
124
125 # dump .BTF section into raw binary file to link with final vmlinux
126 bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \
127 cut -d, -f1 | cut -d' ' -f2)
128 bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \
129 awk '{print $4}')
130 ${OBJCOPY} --change-section-address .BTF=0 \
131 --set-section-flags .BTF=alloc -O binary \
132 --only-section=.BTF ${1} .btf.vmlinux.bin
133 ${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \
134 --rename-section .data=.BTF .btf.vmlinux.bin ${2}
135}
136
137# Create ${2} .o file with all symbols from the ${1} object file
138kallsyms()
139{
140 info KSYM ${2}
141 local kallsymopt;
142
143 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
144 kallsymopt="${kallsymopt} --all-symbols"
145 fi
146
147 if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
148 kallsymopt="${kallsymopt} --absolute-percpu"
149 fi
150
151 if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
152 kallsymopt="${kallsymopt} --base-relative"
153 fi
154
155 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
156 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
157
158 local afile="`basename ${2} .o`.S"
159
160 ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
161 ${CC} ${aflags} -c -o ${2} ${afile}
162}
163
164# Perform one step in kallsyms generation, including temporary linking of
165# vmlinux.
166kallsyms_step()
167{
168 kallsymso_prev=${kallsymso}
169 kallsymso=.tmp_kallsyms${1}.o
170 kallsyms_vmlinux=.tmp_vmlinux${1}
171
172 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
173 kallsyms ${kallsyms_vmlinux} ${kallsymso}
174}
175
176# Create map file with all symbols from ${1}
177# See mksymap for additional details
178mksysmap()
179{
180 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
181}
182
183sorttable()
184{
185 ${objtree}/scripts/sorttable ${1}
186}
187
188# Delete output files in case of error
189cleanup()
190{
191 rm -f .btf.*
192 rm -f .tmp_System.map
193 rm -f .tmp_kallsyms*
194 rm -f .tmp_vmlinux*
195 rm -f System.map
196 rm -f vmlinux
197 rm -f vmlinux.o
198}
199
200on_exit()
201{
202 if [ $? -ne 0 ]; then
203 cleanup
204 fi
205}
206trap on_exit EXIT
207
208on_signals()
209{
210 exit 1
211}
212trap on_signals HUP INT QUIT TERM
213
214#
215#
216# Use "make V=1" to debug this script
217case "${KBUILD_VERBOSE}" in
218*1*)
219 set -x
220 ;;
221esac
222
223if [ "$1" = "clean" ]; then
224 cleanup
225 exit 0
226fi
227
228# We need access to CONFIG_ symbols
229. include/config/auto.conf
230
231# Update version
232info GEN .version
233if [ -r .version ]; then
234 VERSION=$(expr 0$(cat .version) + 1)
235 echo $VERSION > .version
236else
237 rm -f .version
238 echo 1 > .version
239fi;
240
241# final build of init/
242${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init need-builtin=1
243
244#link vmlinux.o
245info LD vmlinux.o
246modpost_link vmlinux.o
247
248# modpost vmlinux.o to check for section mismatches
249${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
250
251info MODINFO modules.builtin.modinfo
252${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
253info GEN modules.builtin
254# The second line aids cases where multiple modules share the same object.
255tr '\0' '\n' < modules.builtin.modinfo | sed -n 's/^[[:alnum:]:_]*\.file=//p' |
256 tr ' ' '\n' | uniq | sed -e 's:^:kernel/:' -e 's/$/.ko/' > modules.builtin
257
258btf_vmlinux_bin_o=""
259if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
260 if gen_btf .tmp_vmlinux.btf .btf.vmlinux.bin.o ; then
261 btf_vmlinux_bin_o=.btf.vmlinux.bin.o
262 else
263 echo >&2 "Failed to generate BTF for vmlinux"
264 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
265 exit 1
266 fi
267fi
268
269kallsymso=""
270kallsymso_prev=""
271kallsyms_vmlinux=""
272if [ -n "${CONFIG_KALLSYMS}" ]; then
273
274 # kallsyms support
275 # Generate section listing all symbols and add it into vmlinux
276 # It's a three step process:
277 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
278 # but __kallsyms is empty.
279 # Running kallsyms on that gives us .tmp_kallsyms1.o with
280 # the right size
281 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
282 # the right size, but due to the added section, some
283 # addresses have shifted.
284 # From here, we generate a correct .tmp_kallsyms2.o
285 # 3) That link may have expanded the kernel image enough that
286 # more linker branch stubs / trampolines had to be added, which
287 # introduces new names, which further expands kallsyms. Do another
288 # pass if that is the case. In theory it's possible this results
289 # in even more stubs, but unlikely.
290 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
291 # other bugs.
292 # 4) The correct ${kallsymso} is linked into the final vmlinux.
293 #
294 # a) Verify that the System.map from vmlinux matches the map from
295 # ${kallsymso}.
296
297 kallsyms_step 1
298 kallsyms_step 2
299
300 # step 3
301 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
302 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
303
304 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
305 kallsyms_step 3
306 fi
307fi
308
309vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
310
311if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then
312 info SORTTAB vmlinux
313 if ! sorttable vmlinux; then
314 echo >&2 Failed to sort kernel tables
315 exit 1
316 fi
317fi
318
319info SYSMAP System.map
320mksysmap vmlinux System.map
321
322# step a (see comment above)
323if [ -n "${CONFIG_KALLSYMS}" ]; then
324 mksysmap ${kallsyms_vmlinux} .tmp_System.map
325
326 if ! cmp -s System.map .tmp_System.map; then
327 echo >&2 Inconsistent kallsyms data
328 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
329 exit 1
330 fi
331fi