xref: /linux/scripts/link-vmlinux.sh (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
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} ${2}
37	fi
38}
39
40# Thin archive build here makes a final archive with
41# symbol table and indexes from vmlinux objects, which can be
42# used as input to linker.
43#
44# Traditional incremental style of link does not require this step
45#
46# built-in.o output file
47#
48archive_builtin()
49{
50	if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
51		info AR built-in.o
52		rm -f built-in.o;
53		${AR} rcsT${KBUILD_ARFLAGS} built-in.o			\
54					${KBUILD_VMLINUX_INIT}		\
55					${KBUILD_VMLINUX_MAIN}
56	fi
57}
58
59# Link of vmlinux.o used for section mismatch analysis
60# ${1} output file
61modpost_link()
62{
63	local objects
64
65	if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
66		objects="--whole-archive built-in.o"
67	else
68		objects="${KBUILD_VMLINUX_INIT}				\
69			--start-group					\
70			${KBUILD_VMLINUX_MAIN}				\
71			--end-group"
72	fi
73	${LD} ${LDFLAGS} -r -o ${1} ${objects}
74}
75
76# Link of vmlinux
77# ${1} - optional extra .o files
78# ${2} - output file
79vmlinux_link()
80{
81	local lds="${objtree}/${KBUILD_LDS}"
82	local objects
83
84	if [ "${SRCARCH}" != "um" ]; then
85		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
86			objects="--whole-archive built-in.o ${1}"
87		else
88			objects="${KBUILD_VMLINUX_INIT}			\
89				--start-group				\
90				${KBUILD_VMLINUX_MAIN}			\
91				--end-group				\
92				${1}"
93		fi
94
95		${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}		\
96			-T ${lds} ${objects}
97	else
98		if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
99			objects="-Wl,--whole-archive built-in.o ${1}"
100		else
101			objects="${KBUILD_VMLINUX_INIT}			\
102				-Wl,--start-group			\
103				${KBUILD_VMLINUX_MAIN}			\
104				-Wl,--end-group				\
105				${1}"
106		fi
107
108		${CC} ${CFLAGS_vmlinux} -o ${2}				\
109			-Wl,-T,${lds}					\
110			${objects}					\
111			-lutil -lrt -lpthread
112		rm -f linux
113	fi
114}
115
116
117# Create ${2} .o file with all symbols from the ${1} object file
118kallsyms()
119{
120	info KSYM ${2}
121	local kallsymopt;
122
123	if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
124		kallsymopt="${kallsymopt} --symbol-prefix=_"
125	fi
126
127	if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
128		kallsymopt="${kallsymopt} --all-symbols"
129	fi
130
131	if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
132		kallsymopt="${kallsymopt} --absolute-percpu"
133	fi
134
135	if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
136		kallsymopt="${kallsymopt} --base-relative"
137	fi
138
139	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
140		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
141
142	local afile="`basename ${2} .o`.S"
143
144	${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
145	${CC} ${aflags} -c -o ${2} ${afile}
146}
147
148# Create map file with all symbols from ${1}
149# See mksymap for additional details
150mksysmap()
151{
152	${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
153}
154
155sortextable()
156{
157	${objtree}/scripts/sortextable ${1}
158}
159
160# Delete output files in case of error
161cleanup()
162{
163	rm -f .old_version
164	rm -f .tmp_System.map
165	rm -f .tmp_kallsyms*
166	rm -f .tmp_version
167	rm -f .tmp_vmlinux*
168	rm -f built-in.o
169	rm -f System.map
170	rm -f vmlinux
171	rm -f vmlinux.o
172}
173
174on_exit()
175{
176	if [ $? -ne 0 ]; then
177		cleanup
178	fi
179}
180trap on_exit EXIT
181
182on_signals()
183{
184	exit 1
185}
186trap on_signals HUP INT QUIT TERM
187
188#
189#
190# Use "make V=1" to debug this script
191case "${KBUILD_VERBOSE}" in
192*1*)
193	set -x
194	;;
195esac
196
197if [ "$1" = "clean" ]; then
198	cleanup
199	exit 0
200fi
201
202# We need access to CONFIG_ symbols
203case "${KCONFIG_CONFIG}" in
204*/*)
205	. "${KCONFIG_CONFIG}"
206	;;
207*)
208	# Force using a file from the current directory
209	. "./${KCONFIG_CONFIG}"
210esac
211
212# Update version
213info GEN .version
214if [ ! -r .version ]; then
215	rm -f .version;
216	echo 1 >.version;
217else
218	mv .version .old_version;
219	expr 0$(cat .old_version) + 1 >.version;
220fi;
221
222# final build of init/
223${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GCC_PLUGINS_CFLAGS}"
224
225archive_builtin
226
227#link vmlinux.o
228info LD vmlinux.o
229modpost_link vmlinux.o
230
231# modpost vmlinux.o to check for section mismatches
232${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
233
234kallsymso=""
235kallsyms_vmlinux=""
236if [ -n "${CONFIG_KALLSYMS}" ]; then
237
238	# kallsyms support
239	# Generate section listing all symbols and add it into vmlinux
240	# It's a three step process:
241	# 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
242	#     but __kallsyms is empty.
243	#     Running kallsyms on that gives us .tmp_kallsyms1.o with
244	#     the right size
245	# 2)  Link .tmp_vmlinux2 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_kallsyms2.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	#     ${kallsymso}.
260
261	kallsymso=.tmp_kallsyms2.o
262	kallsyms_vmlinux=.tmp_vmlinux2
263
264	# step 1
265	vmlinux_link "" .tmp_vmlinux1
266	kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
267
268	# step 2
269	vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
270	kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
271
272	# step 3
273	size1=$(stat -c "%s" .tmp_kallsyms1.o)
274	size2=$(stat -c "%s" .tmp_kallsyms2.o)
275
276	if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
277		kallsymso=.tmp_kallsyms3.o
278		kallsyms_vmlinux=.tmp_vmlinux3
279
280		vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
281
282		kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
283	fi
284fi
285
286info LD vmlinux
287vmlinux_link "${kallsymso}" vmlinux
288
289if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
290	info SORTEX vmlinux
291	sortextable vmlinux
292fi
293
294info SYSMAP System.map
295mksysmap vmlinux System.map
296
297# step a (see comment above)
298if [ -n "${CONFIG_KALLSYMS}" ]; then
299	mksysmap ${kallsyms_vmlinux} .tmp_System.map
300
301	if ! cmp -s System.map .tmp_System.map; then
302		echo >&2 Inconsistent kallsyms data
303		echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
304		exit 1
305	fi
306fi
307
308# We made a new kernel - delete old version file
309rm -f .old_version
310