projects/linux·blob uaccess-cleanups · refs

315 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 "^$1=y" include/config/auto.conf
38}
39
40# Nice output in kbuild format
41# Will be suppressed by "make -s"
42info()
43{
44 printf " %-7s %s\n" "${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# Check if kallsymso_prev and kallsymso differ
110# If symbol sizes within ${kallsymso} change, any symbols within vmlinux are
111# likely to shift, invalidating ${kallsymso}.
112# Since file size can remain unchanged even if symbol sizes change, compare the
113# actual symbols instead of relying on file size only.
114kallsymso_changed()
115{
116 ${NM} -n "${kallsymso_prev}" > "${kallsymso_prev}.sym"
117 ${NM} -n "${kallsymso}" > "${kallsymso}.sym"
118 ! cmp -s "${kallsymso_prev}.sym" "${kallsymso}.sym"
119}
120
121# Create ${2}.o file with all symbols from the ${1} object file
122kallsyms()
123{
124 local kallsymopt;
125
126 if is_enabled CONFIG_KALLSYMS_ALL; then
127 kallsymopt="${kallsymopt} --all-symbols"
128 fi
129
130 if is_enabled CONFIG_64BIT || is_enabled CONFIG_RELOCATABLE; then
131 kallsymopt="${kallsymopt} --pc-relative"
132 fi
133
134 info KSYMS "${2}.S"
135 scripts/kallsyms ${kallsymopt} "${1}" > "${2}.S"
136
137 info AS "${2}.o"
138 ${CC} ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS} \
139 ${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL} -c -o "${2}.o" "${2}.S"
140
141 kallsymso_prev="${kallsymso:-}"
142 kallsymso=${2}.o
143}
144
145# Perform kallsyms for the given temporary vmlinux.
146sysmap_and_kallsyms()
147{
148 mksysmap "${1}" "${1}.syms"
149 kallsyms "${1}.syms" "${1}.kallsyms"
150
151 kallsyms_sysmap=${1}.syms
152}
153
154# Create map file with all symbols from ${1}
155# See mksymap for additional details
156mksysmap()
157{
158 info NM ${2}
159 ${NM} -n "${1}" | sed -f "${srctree}/scripts/mksysmap" > "${2}"
160}
161
162sorttable()
163{
164 ${NM} -S ${1} > .tmp_vmlinux.nm-sort
165 ${objtree}/scripts/sorttable -s .tmp_vmlinux.nm-sort ${1}
166}
167
168cleanup()
169{
170 rm -f .btf.*
171 rm -f .tmp_vmlinux.nm-sort
172 rm -f System.map
173 rm -f vmlinux
174 rm -f vmlinux.map
175}
176
177# Use "make V=1" to debug this script
178case "${KBUILD_VERBOSE}" in
179*1*)
180 set -x
181 ;;
182esac
183
184if [ "$1" = "clean" ]; then
185 cleanup
186 exit 0
187fi
188
189${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init init/version-timestamp.o
190
191arch_vmlinux_o=
192if is_enabled CONFIG_ARCH_WANTS_PRE_LINK_VMLINUX; then
193 arch_vmlinux_o=arch/${SRCARCH}/tools/vmlinux.arch.o
194fi
195
196btf_vmlinux_bin_o=
197btfids_vmlinux=
198kallsymso=
199strip_debug=
200generate_map=
201
202# Use "make UT=1" to trigger warnings on unused tracepoints
203case "${WARN_ON_UNUSED_TRACEPOINTS}" in
204*1*)
205 ${objtree}/scripts/tracepoint-update vmlinux.o
206 ;;
207esac
208
209if is_enabled CONFIG_KALLSYMS; then
210 true > .tmp_vmlinux0.syms
211 kallsyms .tmp_vmlinux0.syms .tmp_vmlinux0.kallsyms
212fi
213
214if is_enabled CONFIG_KALLSYMS || is_enabled CONFIG_DEBUG_INFO_BTF; then
215
216 # The kallsyms linking does not need debug symbols, but the BTF does.
217 if ! is_enabled CONFIG_DEBUG_INFO_BTF; then
218 strip_debug=1
219 fi
220
221 vmlinux_link .tmp_vmlinux1
222fi
223
224if is_enabled CONFIG_DEBUG_INFO_BTF; then
225 info BTF .tmp_vmlinux1
226 if ! ${CONFIG_SHELL} ${srctree}/scripts/gen-btf.sh .tmp_vmlinux1; then
227 echo >&2 "Failed to generate BTF for vmlinux"
228 echo >&2 "Try to disable CONFIG_DEBUG_INFO_BTF"
229 exit 1
230 fi
231 btf_vmlinux_bin_o=.tmp_vmlinux1.btf.o
232 btfids_vmlinux=.tmp_vmlinux1.BTF_ids
233fi
234
235if is_enabled CONFIG_KALLSYMS; then
236
237 # kallsyms support
238 # Generate section listing all symbols and add it into vmlinux
239 # It's a four step process:
240 # 0) Generate a dummy __kallsyms with empty symbol list.
241 # 1) Link .tmp_vmlinux1.kallsyms so it has all symbols and sections,
242 # with a dummy __kallsyms.
243 # Running kallsyms on that gives us .tmp_vmlinux1.kallsyms.o with
244 # the right size
245 # 2) Link .tmp_vmlinux2.kallsyms so it now has a __kallsyms section of
246 # the right size, but due to the added section, some
247 # addresses have shifted.
248 # From here, we generate a correct .tmp_vmlinux2.kallsyms.o
249 # 3) That link may have expanded the kernel image enough that
250 # more linker branch stubs / trampolines had to be added, which
251 # introduces new names, which further expands kallsyms. Do another
252 # pass if that is the case. In theory it's possible this results
253 # in even more stubs, but unlikely.
254 # KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
255 # other bugs.
256 # 4) The correct ${kallsymso} is linked into the final vmlinux.
257 #
258 # a) Verify that the System.map from vmlinux matches the map from
259 # ${kallsymso}.
260
261 # The kallsyms linking does not need debug symbols included.
262 strip_debug=1
263
264 sysmap_and_kallsyms .tmp_vmlinux1
265 size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
266
267 vmlinux_link .tmp_vmlinux2
268 sysmap_and_kallsyms .tmp_vmlinux2
269 size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" ${kallsymso})
270
271 # Due to alignment, file size of the kallsymso object file might remain
272 # unchanged even if individual symbols within change size. Changed
273 # symbol sizes can still shift other symbols, though. Therefore, don't
274 # rely on file size alone.
275 if [ $size1 -ne $size2 ] || kallsymso_changed || \
276 [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
277 vmlinux_link .tmp_vmlinux3
278 sysmap_and_kallsyms .tmp_vmlinux3
279 fi
280fi
281
282strip_debug=
283
284if is_enabled CONFIG_VMLINUX_MAP; then
285 generate_map=1
286fi
287
288vmlinux_link "${VMLINUX}"
289
290if is_enabled CONFIG_DEBUG_INFO_BTF; then
291 info BTFIDS ${VMLINUX}
292 ${RESOLVE_BTFIDS} --patch_btfids ${btfids_vmlinux} ${VMLINUX}
293fi
294
295mksysmap "${VMLINUX}" System.map
296
297if is_enabled CONFIG_BUILDTIME_TABLE_SORT; then
298 info SORTTAB "${VMLINUX}"
299 if ! sorttable "${VMLINUX}"; then
300 echo >&2 Failed to sort kernel tables
301 exit 1
302 fi
303fi
304
305# step a (see comment above)
306if is_enabled CONFIG_KALLSYMS; then
307 if ! cmp -s System.map "${kallsyms_sysmap}"; then
308 echo >&2 Inconsistent kallsyms data
309 echo >&2 'Try "make KALLSYMS_EXTRA_PASS=1" as a workaround'
310 exit 1
311 fi
312fi
313
314# For fixdep
315echo "${VMLINUX}: $0" > ".${VMLINUX}.d"