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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_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
78 kallsymopt="${kallsymopt} --symbol-prefix=_"
79 fi
80
81 if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
82 kallsymopt="${kallsymopt} --all-symbols"
83 fi
84
85 if [ -n "${CONFIG_ARM}" ] && [ -n "${CONFIG_PAGE_OFFSET}" ]; then
86 kallsymopt="${kallsymopt} --page-offset=$CONFIG_PAGE_OFFSET"
87 fi
88
89 if [ -n "${CONFIG_X86_64}" ]; then
90 kallsymopt="${kallsymopt} --absolute-percpu"
91 fi
92
93 local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
94 ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
95
96 ${NM} -n ${1} | \
97 scripts/kallsyms ${kallsymopt} | \
98 ${CC} ${aflags} -c -o ${2} -x assembler-with-cpp -
99}
100
101# Create map file with all symbols from ${1}
102# See mksymap for additional details
103mksysmap()
104{
105 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
106}
107
108sortextable()
109{
110 ${objtree}/scripts/sortextable ${1}
111}
112
113# Delete output files in case of error
114trap cleanup SIGHUP SIGINT SIGQUIT SIGTERM ERR
115cleanup()
116{
117 rm -f .old_version
118 rm -f .tmp_System.map
119 rm -f .tmp_kallsyms*
120 rm -f .tmp_version
121 rm -f .tmp_vmlinux*
122 rm -f System.map
123 rm -f vmlinux
124 rm -f vmlinux.o
125}
126
127#
128#
129# Use "make V=1" to debug this script
130case "${KBUILD_VERBOSE}" in
131*1*)
132 set -x
133 ;;
134esac
135
136if [ "$1" = "clean" ]; then
137 cleanup
138 exit 0
139fi
140
141# We need access to CONFIG_ symbols
142case "${KCONFIG_CONFIG}" in
143*/*)
144 . "${KCONFIG_CONFIG}"
145 ;;
146*)
147 # Force using a file from the current directory
148 . "./${KCONFIG_CONFIG}"
149esac
150
151#link vmlinux.o
152info LD vmlinux.o
153modpost_link vmlinux.o
154
155# modpost vmlinux.o to check for section mismatches
156${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
157
158# Update version
159info GEN .version
160if [ ! -r .version ]; then
161 rm -f .version;
162 echo 1 >.version;
163else
164 mv .version .old_version;
165 expr 0$(cat .old_version) + 1 >.version;
166fi;
167
168# final build of init/
169${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
170
171kallsymso=""
172kallsyms_vmlinux=""
173if [ -n "${CONFIG_KALLSYMS}" ]; then
174
175 # kallsyms support
176 # Generate section listing all symbols and add it into vmlinux
177 # It's a three step process:
178 # 1) Link .tmp_vmlinux1 so it has all symbols and sections,
179 # but __kallsyms is empty.
180 # Running kallsyms on that gives us .tmp_kallsyms1.o with
181 # the right size
182 # 2) Link .tmp_vmlinux2 so it now has a __kallsyms section of
183 # the right size, but due to the added section, some
184 # addresses have shifted.
185 # From here, we generate a correct .tmp_kallsyms2.o
186 # 2a) We may use an extra pass as this has been necessary to
187 # woraround some alignment related bugs.
188 # KALLSYMS_EXTRA_PASS=1 is used to trigger this.
189 # 3) The correct ${kallsymso} is linked into the final vmlinux.
190 #
191 # a) Verify that the System.map from vmlinux matches the map from
192 # ${kallsymso}.
193
194 kallsymso=.tmp_kallsyms2.o
195 kallsyms_vmlinux=.tmp_vmlinux2
196
197 # step 1
198 vmlinux_link "" .tmp_vmlinux1
199 kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
200
201 # step 2
202 vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
203 kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
204
205 # step 2a
206 if [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
207 kallsymso=.tmp_kallsyms3.o
208 kallsyms_vmlinux=.tmp_vmlinux3
209
210 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
211
212 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
213 fi
214fi
215
216info LD vmlinux
217vmlinux_link "${kallsymso}" vmlinux
218
219if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
220 info SORTEX vmlinux
221 sortextable vmlinux
222fi
223
224info SYSMAP System.map
225mksysmap vmlinux System.map
226
227# step a (see comment above)
228if [ -n "${CONFIG_KALLSYMS}" ]; then
229 mksysmap ${kallsyms_vmlinux} .tmp_System.map
230
231 if ! cmp -s System.map .tmp_System.map; then
232 echo >&2 Inconsistent kallsyms data
233 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
234 cleanup
235 exit 1
236 fi
237fi
238
239# We made a new kernel - delete old version file
240rm -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 in vmlinux.a and $(KBUILD_VMLINUX_LIBS).
7# vmlinux.a contains objects that are linked unconditionally.
8# $(KBUILD_VMLINUX_LIBS) are archives which are linked conditionally
9# (not within --whole-archive), and do not require symbol indexes added.
10#
11# vmlinux
12# ^
13# |
14# +--< vmlinux.a
15# |
16# +--< $(KBUILD_VMLINUX_LIBS)
17# | +--< lib/lib.a + 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
31LD="$1"
32KBUILD_LDFLAGS="$2"
33LDFLAGS_vmlinux="$3"
34
35is_enabled() {
36 grep -q "^$1=y" include/config/auto.conf
37}
38
39# Nice output in kbuild format
40# Will be supressed by "make -s"
41info()
42{
43 printf " %-7s %s\n" "${1}" "${2}"
44}
45
46# Link of vmlinux
47# ${1} - output file
48# ${2}, ${3}, ... - optional extra .o files
49vmlinux_link()
50{
51 local output=${1}
52 local objs
53 local libs
54 local ld
55 local ldflags
56 local ldlibs
57
58 info LD ${output}
59
60 # skip output file argument
61 shift
62
63 if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
64 # Use vmlinux.o instead of performing the slow LTO link again.
65 objs=vmlinux.o
66 libs=
67 else
68 objs=vmlinux.a
69 libs="${KBUILD_VMLINUX_LIBS}"
70 fi
71
72 if is_enabled CONFIG_MODULES; then
73 objs="${objs} .vmlinux.export.o"
74 fi
75
76 objs="${objs} init/version-timestamp.o"
77
78 if [ "${SRCARCH}" = "um" ]; then
79 wl=-Wl,
80 ld="${CC}"
81 ldflags="${CFLAGS_vmlinux}"
82 ldlibs="-lutil -lrt -lpthread"
83 else
84 wl=
85 ld="${LD}"
86 ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
87 ldlibs=
88 fi
89
90 ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"
91
92 # The kallsyms linking does not need debug symbols included.
93 if [ "$output" != "${output#.tmp_vmlinux.kallsyms}" ] ; then
94 ldflags="${ldflags} ${wl}--strip-debug"
95 fi
96
97 if is_enabled CONFIG_VMLINUX_MAP; then
98 ldflags="${ldflags} ${wl}-Map=${output}.map"
99 fi
100
101 ${ld} ${ldflags} -o ${output} \
102 ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \
103 ${wl}--start-group ${libs} ${wl}--end-group \
104 $@ ${ldlibs}
105}
106
107# generate .BTF typeinfo from DWARF debuginfo
108# ${1} - vmlinux image
109# ${2} - file to dump raw BTF data into
110gen_btf()
111{
112 local pahole_ver
113
114 if ! [ -x "$(command -v ${PAHOLE})" ]; then
115 echo >&2 "BTF: ${1}: pahole (${PAHOLE}) is not available"
116 return 1
117 fi
118
119 pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
120 if [ "${pahole_ver}" -lt "116" ]; then
121 echo >&2 "BTF: ${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.16"
122 return 1
123 fi
124
125 vmlinux_link ${1}
126
127 info "BTF" ${2}
128 LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
129
130 # Create ${2} which contains just .BTF section but no symbols. Add
131 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
132 # deletes all symbols including __start_BTF and __stop_BTF, which will
133 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
134 # objcopy warnings: "empty loadable segment detected at ..."
135 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
136 --strip-all ${1} ${2} 2>/dev/null
137 # Change e_type to ET_REL so that it can be used to link final vmlinux.
138 # GNU ld 2.35+ and lld do not allow an ET_EXEC input.
139 if is_enabled CONFIG_CPU_BIG_ENDIAN; then
140 et_rel='\0\1'
141 else
142 et_rel='\1\0'
143 fi
144 printf "${et_rel}" | dd of=${2} conv=notrunc bs=1 seek=16 status=none
145}
146
147# Create ${2} .S file with all symbols from the ${1} object file
148kallsyms()
149{
150 local kallsymopt;
151
152 if is_enabled CONFIG_KALLSYMS_ALL; then
153 kallsymopt="${kallsymopt} --all-symbols"
154 fi
155
156 if is_enabled CONFIG_KALLSYMS_ABSOLUTE_PERCPU; then
157 kallsymopt="${kallsymopt} --absolute-percpu"
158 fi
159
160 if is_enabled CONFIG_KALLSYMS_BASE_RELATIVE; then
161 kallsymopt="${kallsymopt} --base-relative"
162 fi
163
164 if is_enabled CONFIG_LTO_CLANG; then
165 kallsymopt="${kallsymopt} --lto-clang"
166 fi
167
168 info KSYMS ${2}
169 scripts/kallsyms ${kallsymopt} ${1} > ${2}
170}
171
172# Perform one step in kallsyms generation, including temporary linking of
173# vmlinux.
174kallsyms_step()
175{
176 kallsymso_prev=${kallsymso}
177 kallsyms_vmlinux=.tmp_vmlinux.kallsyms${1}
178 kallsymso=${kallsyms_vmlinux}.o
179 kallsyms_S=${kallsyms_vmlinux}.S
180
181 vmlinux_link ${kallsyms_vmlinux} "${kallsymso_prev}" ${btf_vmlinux_bin_o}
182 mksysmap ${kallsyms_vmlinux} ${kallsyms_vmlinux}.syms ${kallsymso_prev}
183 kallsyms ${kallsyms_vmlinux}.syms ${kallsyms_S}
184
185 info AS ${kallsyms_S}
186 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
187 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} \
188 -c -o ${kallsymso} ${kallsyms_S}
189}
190
191# Create map file with all symbols from ${1}
192# See mksymap for additional details
193mksysmap()
194{
195 info NM ${2}
196 ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2} ${3}
197}
198
199sorttable()
200{
201 ${objtree}/scripts/sorttable ${1}
202}
203
204# Delete output files in case of error
205cleanup()
206{
207 rm -f .btf.*
208 rm -f System.map
209 rm -f vmlinux
210 rm -f vmlinux.map
211}
212
213# Use "make V=1" to debug this script
214case "${KBUILD_VERBOSE}" in
215*1*)
216 set -x
217 ;;
218esac
219
220if [ "$1" = "clean" ]; then
221 cleanup
222 exit 0
223fi
224
225${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
226
227btf_vmlinux_bin_o=""
228if is_enabled CONFIG_DEBUG_INFO_BTF; then
229 btf_vmlinux_bin_o=.btf.vmlinux.bin.o
230 if ! gen_btf .tmp_vmlinux.btf $btf_vmlinux_bin_o ; then
231 echo >&2 "Failed to generate BTF for vmlinux"
232 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
233 exit 1
234 fi
235fi
236
237kallsymso=""
238kallsymso_prev=""
239kallsyms_vmlinux=""
240if is_enabled CONFIG_KALLSYMS; then
241
242 # kallsyms support
243 # Generate section listing all symbols and add it into vmlinux
244 # It's a three step process:
245 # 1) Link .tmp_vmlinux.kallsyms1 so it has all symbols and sections,
246 # but __kallsyms is empty.
247 # Running kallsyms on that gives us .tmp_kallsyms1.o with
248 # the right size
249 # 2) Link .tmp_vmlinux.kallsyms2 so it now has a __kallsyms section of
250 # the right size, but due to the added section, some
251 # addresses have shifted.
252 # From here, we generate a correct .tmp_vmlinux.kallsyms2.o
253 # 3) That link may have expanded the kernel image enough that
254 # more linker branch stubs / trampolines had to be added, which
255 # introduces new names, which further expands kallsyms. Do another
256 # pass if that is the case. In theory it's possible this results
257 # in even more stubs, but unlikely.
258 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
259 # other bugs.
260 # 4) The correct ${kallsymso} is linked into the final vmlinux.
261 #
262 # a) Verify that the System.map from vmlinux matches the map from
263 # ${kallsymso}.
264
265 kallsyms_step 1
266 kallsyms_step 2
267
268 # step 3
269 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso_prev})
270 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
271
272 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
273 kallsyms_step 3
274 fi
275fi
276
277vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o}
278
279# fill in BTF IDs
280if is_enabled CONFIG_DEBUG_INFO_BTF && is_enabled CONFIG_BPF; then
281 info BTFIDS vmlinux
282 ${RESOLVE_BTFIDS} vmlinux
283fi
284
285mksysmap vmlinux System.map ${kallsymso}
286
287if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
288 info SORTTAB vmlinux
289 if ! sorttable vmlinux; then
290 echo >&2 Failed to sort kernel tables
291 exit 1
292 fi
293fi
294
295# step a (see comment above)
296if is_enabled CONFIG_KALLSYMS; then
297 if ! cmp -s System.map ${kallsyms_vmlinux}.syms; then
298 echo >&2 Inconsistent kallsyms data
299 echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
300 exit 1
301 fi
302fi
303
304# For fixdep
305echo "vmlinux: $0" > .vmlinux.d