915775eb2921b56c01d6c06cc6cb9daa786376a7
[muen/linux.git] / scripts / link-vmlinux.sh
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 #   +-< ${kallsymso} (see description in KALLSYMS section)
22 #
23 # vmlinux version (uname -v) cannot be updated during normal
24 # descending-into-subdirs phase since we do not yet know if we need to
25 # update vmlinux.
26 # Therefore this step is delayed until just before final link of vmlinux.
27 #
28 # System.map is generated to document addresses of all kernel symbols
29
30 # Error out on error
31 set -e
32
33 # Nice output in kbuild format
34 # Will be supressed by "make -s"
35 info()
36 {
37         if [ "${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
44 modpost_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} - optional extra .o files
60 # ${2} - output file
61 vmlinux_link()
62 {
63         local lds="${objtree}/${KBUILD_LDS}"
64         local objects
65
66         if [ "${SRCARCH}" != "um" ]; then
67                 objects="--whole-archive                        \
68                         ${KBUILD_VMLINUX_OBJS}                  \
69                         --no-whole-archive                      \
70                         --start-group                           \
71                         ${KBUILD_VMLINUX_LIBS}                  \
72                         --end-group                             \
73                         ${1}"
74
75                 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}      \
76                         -T ${lds} ${objects}
77         else
78                 objects="-Wl,--whole-archive                    \
79                         ${KBUILD_VMLINUX_OBJS}                  \
80                         -Wl,--no-whole-archive                  \
81                         -Wl,--start-group                       \
82                         ${KBUILD_VMLINUX_LIBS}                  \
83                         -Wl,--end-group                         \
84                         ${1}"
85
86                 ${CC} ${CFLAGS_vmlinux} -o ${2}                 \
87                         -Wl,-T,${lds}                           \
88                         ${objects}                              \
89                         -lutil -lrt -lpthread
90                 rm -f linux
91         fi
92 }
93
94 # generate .BTF typeinfo from DWARF debuginfo
95 gen_btf()
96 {
97         local pahole_ver;
98
99         if ! [ -x "$(command -v ${PAHOLE})" ]; then
100                 info "BTF" "${1}: pahole (${PAHOLE}) is not available"
101                 return 0
102         fi
103
104         pahole_ver=$(${PAHOLE} --version | sed -E 's/v([0-9]+)\.([0-9]+)/\1\2/')
105         if [ "${pahole_ver}" -lt "113" ]; then
106                 info "BTF" "${1}: pahole version $(${PAHOLE} --version) is too old, need at least v1.13"
107                 return 0
108         fi
109
110         info "BTF" ${1}
111         LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1}
112 }
113
114 # Create ${2} .o file with all symbols from the ${1} object file
115 kallsyms()
116 {
117         info KSYM ${2}
118         local kallsymopt;
119
120         if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
121                 kallsymopt="${kallsymopt} --all-symbols"
122         fi
123
124         if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
125                 kallsymopt="${kallsymopt} --absolute-percpu"
126         fi
127
128         if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
129                 kallsymopt="${kallsymopt} --base-relative"
130         fi
131
132         local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
133                       ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
134
135         local afile="`basename ${2} .o`.S"
136
137         ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
138         ${CC} ${aflags} -c -o ${2} ${afile}
139 }
140
141 # Create map file with all symbols from ${1}
142 # See mksymap for additional details
143 mksysmap()
144 {
145         ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
146 }
147
148 sortextable()
149 {
150         ${objtree}/scripts/sortextable ${1}
151 }
152
153 # Delete output files in case of error
154 cleanup()
155 {
156         rm -f .tmp_System.map
157         rm -f .tmp_kallsyms*
158         rm -f .tmp_vmlinux*
159         rm -f System.map
160         rm -f vmlinux
161         rm -f vmlinux.o
162 }
163
164 on_exit()
165 {
166         if [ $? -ne 0 ]; then
167                 cleanup
168         fi
169 }
170 trap on_exit EXIT
171
172 on_signals()
173 {
174         exit 1
175 }
176 trap on_signals HUP INT QUIT TERM
177
178 #
179 #
180 # Use "make V=1" to debug this script
181 case "${KBUILD_VERBOSE}" in
182 *1*)
183         set -x
184         ;;
185 esac
186
187 if [ "$1" = "clean" ]; then
188         cleanup
189         exit 0
190 fi
191
192 # We need access to CONFIG_ symbols
193 . include/config/auto.conf
194
195 # Update version
196 info GEN .version
197 if [ -r .version ]; then
198         VERSION=$(expr 0$(cat .version) + 1)
199         echo $VERSION > .version
200 else
201         rm -f .version
202         echo 1 > .version
203 fi;
204
205 # final build of init/
206 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
207
208 #link vmlinux.o
209 info LD vmlinux.o
210 modpost_link vmlinux.o
211
212 # modpost vmlinux.o to check for section mismatches
213 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" MODPOST_VMLINUX=1
214
215 info MODINFO modules.builtin.modinfo
216 ${OBJCOPY} -j .modinfo -O binary vmlinux.o modules.builtin.modinfo
217
218 kallsymso=""
219 kallsyms_vmlinux=""
220 if [ -n "${CONFIG_KALLSYMS}" ]; then
221
222         # kallsyms support
223         # Generate section listing all symbols and add it into vmlinux
224         # It's a three step process:
225         # 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
226         #     but __kallsyms is empty.
227         #     Running kallsyms on that gives us .tmp_kallsyms1.o with
228         #     the right size
229         # 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
230         #     the right size, but due to the added section, some
231         #     addresses have shifted.
232         #     From here, we generate a correct .tmp_kallsyms2.o
233         # 3)  That link may have expanded the kernel image enough that
234         #     more linker branch stubs / trampolines had to be added, which
235         #     introduces new names, which further expands kallsyms. Do another
236         #     pass if that is the case. In theory it's possible this results
237         #     in even more stubs, but unlikely.
238         #     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
239         #     other bugs.
240         # 4)  The correct ${kallsymso} is linked into the final vmlinux.
241         #
242         # a)  Verify that the System.map from vmlinux matches the map from
243         #     ${kallsymso}.
244
245         kallsymso=.tmp_kallsyms2.o
246         kallsyms_vmlinux=.tmp_vmlinux2
247
248         # step 1
249         vmlinux_link "" .tmp_vmlinux1
250         kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
251
252         # step 2
253         vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
254         kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
255
256         # step 3
257         size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
258         size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)
259
260         if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
261                 kallsymso=.tmp_kallsyms3.o
262                 kallsyms_vmlinux=.tmp_vmlinux3
263
264                 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
265
266                 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
267         fi
268 fi
269
270 info LD vmlinux
271 vmlinux_link "${kallsymso}" vmlinux
272
273 if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then
274         gen_btf vmlinux
275 fi
276
277 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
278         info SORTEX vmlinux
279         sortextable vmlinux
280 fi
281
282 info SYSMAP System.map
283 mksysmap vmlinux System.map
284
285 # step a (see comment above)
286 if [ -n "${CONFIG_KALLSYMS}" ]; then
287         mksysmap ${kallsyms_vmlinux} .tmp_System.map
288
289         if ! cmp -s System.map .tmp_System.map; then
290                 echo >&2 Inconsistent kallsyms data
291                 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
292                 exit 1
293         fi
294 fi