projects/linux·blob v6.15-rc3 · refs

317 lines · 7.7 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 ${output}
59
60 # skip output file argument
61 shift
62
63 if is_enabled CONFIG_LTO_CLANG || is_enabled CONFIG_X86_KERNEL_IBT; then
64 # Use vmlinux.o instead of performing the slow LTO link again.
65 objs=vmlinux.o
66 libs=
67 else
68 objs=vmlinux.a
69 libs="${KBUILD_VMLINUX_LIBS}"
70 fi
71
72 if is_enabled CONFIG_GENERIC_BUILTIN_DTB; then
73 objs="${objs} .builtin-dtbs.o"
74 fi
75
76 if is_enabled CONFIG_MODULES; then
77 objs="${objs} .vmlinux.export.o"
78 fi
79
80 objs="${objs} init/version-timestamp.o"
81
82 if [ "${SRCARCH}" = "um" ]; then
83 wl=-Wl,
84 ld="${CC}"
85 ldflags="${CFLAGS_vmlinux}"
86 ldlibs="-lutil -lrt -lpthread"
87 else
88 wl=
89 ld="${LD}"
90 ldflags="${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux}"
91 ldlibs=
92 fi
93
94 ldflags="${ldflags} ${wl}--script=${objtree}/${KBUILD_LDS}"
95
96 # The kallsyms linking does not need debug symbols included.
97 if [ -n "${strip_debug}" ] ; then
98 ldflags="${ldflags} ${wl}--strip-debug"
99 fi
100
101 if [ -n "${generate_map}" ]; then
102 ldflags="${ldflags} ${wl}-Map=vmlinux.map"
103 fi
104
105 ${ld} ${ldflags} -o ${output} \
106 ${wl}--whole-archive ${objs} ${wl}--no-whole-archive \
107 ${wl}--start-group ${libs} ${wl}--end-group \
108 ${kallsymso} ${btf_vmlinux_bin_o} ${arch_vmlinux_o} ${ldlibs}
109}
110
111# generate .BTF typeinfo from DWARF debuginfo
112# ${1} - vmlinux image
113gen_btf()
114{
115 local btf_data=${1}.btf.o
116
117 info BTF "${btf_data}"
118 LLVM_OBJCOPY="${OBJCOPY}" ${PAHOLE} -J ${PAHOLE_FLAGS} ${1}
119
120 # Create ${btf_data} which contains just .BTF section but no symbols. Add
121 # SHF_ALLOC because .BTF will be part of the vmlinux image. --strip-all
122 # deletes all symbols including __start_BTF and __stop_BTF, which will
123 # be redefined in the linker script. Add 2>/dev/null to suppress GNU
124 # objcopy warnings: "empty loadable segment detected at ..."
125 ${OBJCOPY} --only-section=.BTF --set-section-flags .BTF=alloc,readonly \
126 --strip-all ${1} "${btf_data}" 2>/dev/null
127 # Change e_type to ET_REL so that it can be used to link final vmlinux.
128 # GNU ld 2.35+ and lld do not allow an ET_EXEC input.
129 if is_enabled CONFIG_CPU_BIG_ENDIAN; then
130 et_rel='\0\1'
131 else
132 et_rel='\1\0'
133 fi
134 printf "${et_rel}" | dd of="${btf_data}" conv=notrunc bs=1 seek=16 status=none
135
136 btf_vmlinux_bin_o=${btf_data}
137}
138
139# Create ${2}.o file with all symbols from the ${1} object file
140kallsyms()
141{
142 local kallsymopt;
143
144 if is_enabled CONFIG_KALLSYMS_ALL; then
145 kallsymopt="${kallsymopt} --all-symbols"
146 fi
147
148 info KSYMS "${2}.S"
149 scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"
150
151 info AS "${2}.o"
152 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
153 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S"
154
155 kallsymso=${2}.o
156}
157
158# Perform kallsyms for the given temporary vmlinux.
159sysmap_and_kallsyms()
160{
161 mksysmap "${1}" "${1}.syms"
162 kallsyms "${1}.syms" "${1}.kallsyms"
163
164 kallsyms_sysmap=${1}.syms
165}
166
167# Create map file with all symbols from ${1}
168# See mksymap for additional details
169mksysmap()
170{
171 info NM ${2}
172 ${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}"
173}
174
175sorttable()
176{
177 ${NM} -S ${1} > .tmp_vmlinux.nm-sort
178 ${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1}
179}
180
181cleanup()
182{
183 rm -f .btf.*
184 rm -f .tmp_vmlinux.nm-sort
185 rm -f System.map
186 rm -f vmlinux
187 rm -f vmlinux.map
188}
189
190# Use "make V=1" to debug this script
191case "${KBUILD_VERBOSE}" in
192*1*)
193 set -x
194 ;;
195esac
196
197if [ "$1" = "clean" ]; then
198 cleanup
199 exit 0
200fi
201
202${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
203
204arch_vmlinux_o=
205if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
206 arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o
207fi
208
209btf_vmlinux_bin_o=
210kallsymso=
211strip_debug=
212generate_map=
213
214if is_enabled CONFIG_KALLSYMS; then
215 true > .tmp_vmlinux0.syms
216 kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms
217fi
218
219if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then
220
221 # The kallsyms linking does not need debug symbols, but the BTF does.
222 if ! is_enabled CONFIG_DEBUG_INFO_BTF; then
223 strip_debug=1
224 fi
225
226 vmlinux_link .tmp_vmlinux1
227fi
228
229if is_enabled CONFIG_DEBUG_INFO_BTF; then
230 if ! gen_btf .tmp_vmlinux1; 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
237if is_enabled CONFIG_KALLSYMS; then
238
239 # kallsyms support
240 # Generate section listing all symbols and add it into vmlinux
241 # It's a four step process:
242 # 0) Generate a dummy __kallsyms with empty symbol list.
243 # 1) Link .tmp_vmlinux1.kallsyms so it has all symbols and sections,
244 # with a dummy __kallsyms.
245 # Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with
246 # the right size
247 # 2) Link .tmp_vmlinux2.kallsyms so it now has a __kallsyms section of
248 # the right size, but due to the added section, some
249 # addresses have shifted.
250 # From here, we generate a correct .tmp_vmlinux2.kallsyms.o
251 # 3) That link may have expanded the kernel image enough that
252 # more linker branch stubs / trampolines had to be added, which
253 # introduces new names, which further expands kallsyms. Do another
254 # pass if that is the case. In theory it's possible this results
255 # in even more stubs, but unlikely.
256 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
257 # other bugs.
258 # 4) The correct ${kallsymso} is linked into the final vmlinux.
259 #
260 # a) Verify that the System.map from vmlinux matches the map from
261 # ${kallsymso}.
262
263 # The kallsyms linking does not need debug symbols included.
264 strip_debug=1
265
266 sysmap_and_kallsyms .tmp_vmlinux1
267 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
268
269 vmlinux_link .tmp_vmlinux2
270 sysmap_and_kallsyms .tmp_vmlinux2
271 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
272
273 if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
274 vmlinux_link .tmp_vmlinux3
275 sysmap_and_kallsyms .tmp_vmlinux3
276 fi
277fi
278
279strip_debug=
280
281if is_enabled CONFIG_VMLINUX_MAP; then
282 generate_map=1
283fi
284
285vmlinux_link "${VMLINUX}"
286
287# fill in BTF IDs
288if is_enabled CONFIG_DEBUG_INFO_BTF; then
289 info BTFIDS "${VMLINUX}"
290 RESOLVE_BTFIDS_ARGS=""
291 if is_enabled CONFIG_WERROR; then
292 RESOLVE_BTFIDS_ARGS=" --fatal_warnings "
293 fi
294 ${RESOLVE_BTFIDS} ${RESOLVE_BTFIDS_ARGS} "${VMLINUX}"
295fi
296
297mksysmap "${VMLINUX}" System.map
298
299if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
300 info SORTTAB "${VMLINUX}"
301 if ! sorttable "${VMLINUX}"; then
302 echo >&2 Failed to sort kernel tables
303 exit 1
304 fi
305fi
306
307# step a (see comment above)
308if is_enabled CONFIG_KALLSYMS; then
309 if ! cmp -s System.map "${kallsyms_sysmap}"; then
310 echo >&2 Inconsistent kallsyms data
311 echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
312 exit 1
313 fi
314fi
315
316# For fixdep
317echo "${VMLINUX}: $0" > ".${VMLINUX}.d"