projects/linux·blob v6.19 · refs

322 lines · 7.8 KiB

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"
34VMLINUX="$4"
35
36is_enabled() {
37 grep -q "^$1=y" include/config/auto.conf
38}
39
40# Nice output in kbuild format
41# Will be supressed by "make -s"
42info()
43{
44 printf " %-7s %s\n" "${1}" "${2}"
45}
46
47# Link of vmlinux
48# ${1} - output file
49vmlinux_link()
50{
51 local output=${1}
52 local objs
53 local libs
54 local ld
55 local ldflags
56 local ldlibs
57
58 info LD ${output}
59
60 # skip output file argument
61 shift
62
63 if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT ||
64 is_enabled CONFIG_KLP_BUILD; then
65 # Use vmlinux.o instead of performing the slow LTO link again.
66 objs=vmlinux.o
67 libs=
68 else
69 objs=vmlinux.a
70 libs="${KBUILD_VMLINUX_LIBS}"
71 fi
72
73 if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then
74 objs="${objs} .builtin-dtbs.o"
75 fi
76
77 objs="${objs} .vmlinux.export.o"
78 objs="${objs} init/version-timestamp.o"
79
80 if [ "${SRCARCH}" = "um" ]; then
81 wl=-Wl,
82 ld="${CC}"
83 ldflags="${CFLAGS_vmlinux}"
84 ldlibs="-lutil -lrt -lpthread"
85 else
86 wl=
87 ld="${LD}"
88 ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
89 ldlibs=
90 fi
91
92 ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"
93
94 # The kallsyms linking does not need debug symbols included.
95 if [ -n "${strip_debug}" ] ; then
96 ldflags="${ldflags} ${wl}--strip-debug"
97 fi
98
99 if [ -n "${generate_map}" ]; then
100 ldflags="${ldflags} ${wl}-Map=vmlinux.map"
101 fi
102
103 ${ld} ${ldflags} -o ${output} \
104 ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \
105 ${wl}--start-group ${libs} ${wl}--end-group \
106 ${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}
107}
108
109# generate .BTF typeinfo from DWARF debuginfo
110# ${1} - vmlinux image
111gen_btf()
112{
113 local btf_data=${1}.btf.o
114
115 info BTF "${btf_data}"
116 LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
117
118 # Create ${btf_data} which contains just .BTF section but no symbols. Add
119 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
120 # deletes all symbols including __start_BTF and __stop_BTF, which will
121 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
122 # objcopy warnings: "empty loadable segment detected at ..."
123 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
124 --strip-all ${1} "${btf_data}" 2>/dev/null
125 # Change e_type to ET_REL so that it can be used to link final vmlinux.
126 # GNU ld 2.35+ and lld do not allow an ET_EXEC input.
127 if is_enabled CONFIG_CPU_BIG_ENDIAN; then
128 et_rel='\0\1'
129 else
130 et_rel='\1\0'
131 fi
132 printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none
133
134 btf_vmlinux_bin_o=${btf_data}
135}
136
137# Create ${2}.o file with all symbols from the ${1} object file
138kallsyms()
139{
140 local kallsymopt;
141
142 if is_enabled CONFIG_KALLSYMS_ALL; then
143 kallsymopt="${kallsymopt} --all-symbols"
144 fi
145
146 info KSYMS "${2}.S"
147 scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"
148
149 info AS "${2}.o"
150 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
151 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S"
152
153 kallsymso=${2}.o
154}
155
156# Perform kallsyms for the given temporary vmlinux.
157sysmap_and_kallsyms()
158{
159 mksysmap "${1}" "${1}.syms"
160 kallsyms "${1}.syms" "${1}.kallsyms"
161
162 kallsyms_sysmap=${1}.syms
163}
164
165# Create map file with all symbols from ${1}
166# See mksymap for additional details
167mksysmap()
168{
169 info NM ${2}
170 ${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}"
171}
172
173sorttable()
174{
175 ${NM} -S ${1} > .tmp_vmlinux.nm-sort
176 ${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1}
177}
178
179cleanup()
180{
181 rm -f .btf.*
182 rm -f .tmp_vmlinux.nm-sort
183 rm -f System.map
184 rm -f vmlinux
185 rm -f vmlinux.map
186}
187
188# Use "make V=1" to debug this script
189case "${KBUILD_VERBOSE}" in
190*1*)
191 set -x
192 ;;
193esac
194
195if [ "$1" = "clean" ]; then
196 cleanup
197 exit 0
198fi
199
200${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
201
202arch_vmlinux_o=
203if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
204 arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o
205fi
206
207btf_vmlinux_bin_o=
208kallsymso=
209strip_debug=
210generate_map=
211
212# Use "make UT=1" to trigger warnings on unused tracepoints
213case "${WARN_ON_UNUSED_TRACEPOINTS}" in
214*1*)
215 ${objtree}/scripts/tracepoint-update vmlinux.o
216 ;;
217esac
218
219if is_enabled CONFIG_KALLSYMS; then
220 true > .tmp_vmlinux0.syms
221 kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms
222fi
223
224if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then
225
226 # The kallsyms linking does not need debug symbols, but the BTF does.
227 if ! is_enabled CONFIG_DEBUG_INFO_BTF; then
228 strip_debug=1
229 fi
230
231 vmlinux_link .tmp_vmlinux1
232fi
233
234if is_enabled CONFIG_DEBUG_INFO_BTF; then
235 if ! gen_btf .tmp_vmlinux1; then
236 echo >&2 "Failed to generate BTF for vmlinux"
237 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
238 exit 1
239 fi
240fi
241
242if is_enabled CONFIG_KALLSYMS; then
243
244 # kallsyms support
245 # Generate section listing all symbols and add it into vmlinux
246 # It's a four step process:
247 # 0) Generate a dummy __kallsyms with empty symbol list.
248 # 1) Link .tmp_vmlinux1.kallsyms so it has all symbols and sections,
249 # with a dummy __kallsyms.
250 # Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with
251 # the right size
252 # 2) Link .tmp_vmlinux2.kallsyms so it now has a __kallsyms section of
253 # the right size, but due to the added section, some
254 # addresses have shifted.
255 # From here, we generate a correct .tmp_vmlinux2.kallsyms.o
256 # 3) That link may have expanded the kernel image enough that
257 # more linker branch stubs / trampolines had to be added, which
258 # introduces new names, which further expands kallsyms. Do another
259 # pass if that is the case. In theory it's possible this results
260 # in even more stubs, but unlikely.
261 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
262 # other bugs.
263 # 4) The correct ${kallsymso} is linked into the final vmlinux.
264 #
265 # a) Verify that the System.map from vmlinux matches the map from
266 # ${kallsymso}.
267
268 # The kallsyms linking does not need debug symbols included.
269 strip_debug=1
270
271 sysmap_and_kallsyms .tmp_vmlinux1
272 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
273
274 vmlinux_link .tmp_vmlinux2
275 sysmap_and_kallsyms .tmp_vmlinux2
276 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
277
278 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
279 vmlinux_link .tmp_vmlinux3
280 sysmap_and_kallsyms .tmp_vmlinux3
281 fi
282fi
283
284strip_debug=
285
286if is_enabled CONFIG_VMLINUX_MAP; then
287 generate_map=1
288fi
289
290vmlinux_link "${VMLINUX}"
291
292# fill in BTF IDs
293if is_enabled CONFIG_DEBUG_INFO_BTF; then
294 info BTFIDS "${VMLINUX}"
295 RESOLVE_BTFIDS_ARGS=""
296 if is_enabled CONFIG_WERROR; then
297 RESOLVE_BTFIDS_ARGS=" --fatal_warnings "
298 fi
299 ${RESOLVE_BTFIDS} ${RESOLVE_BTFIDS_ARGS} "${VMLINUX}"
300fi
301
302mksysmap "${VMLINUX}" System.map
303
304if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
305 info SORTTAB "${VMLINUX}"
306 if ! sorttable "${VMLINUX}"; then
307 echo >&2 Failed to sort kernel tables
308 exit 1
309 fi
310fi
311
312# step a (see comment above)
313if is_enabled CONFIG_KALLSYMS; then
314 if ! cmp -s System.map "${kallsyms_sysmap}"; then
315 echo >&2 Inconsistent kallsyms data
316 echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
317 exit 1
318 fi
319fi
320
321# For fixdep
322echo "${VMLINUX}: $0" > ".${VMLINUX}.d"