xref: /linux/scripts/link-vmlinux.sh (revision 93d90ad708b8da6efc0e487b66111aa9db7f70c7)
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# Link of vmlinux.o used for section mismatch analysis
41# ${1} output file
42modpost_link()
43{
44	${LD} ${LDFLAGS} -r -o ${1} ${KBUILD_VMLINUX_INIT}                   \
45		--start-group ${KBUILD_VMLINUX_MAIN} --end-group
46}
47
48# Link of vmlinux
49# ${1} - optional extra .o files
50# ${2} - output file
51vmlinux_link()
52{
53	local lds="${objtree}/${KBUILD_LDS}"
54
55	if [ "${SRCARCH}" != "um" ]; then
56		${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}                  \
57			-T ${lds} ${KBUILD_VMLINUX_INIT}                     \
58			--start-group ${KBUILD_VMLINUX_MAIN} --end-group ${1}
59	else
60		${CC} ${CFLAGS_vmlinux} -o ${2}                              \
61			-Wl,-T,${lds} ${KBUILD_VMLINUX_INIT}                 \
62			-Wl,--start-group                                    \
63				 ${KBUILD_VMLINUX_MAIN}                      \
64			-Wl,--end-group                                      \
65			-lutil ${1}
66		rm -f linux
67	fi
68}
69
70
71# Create ${2} .o file with all symbols from the ${1} object file
72kallsyms()
73{
74	info KSYM ${2}
75	local kallsymopt;
76
77	if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
78		kallsymopt="${kallsymopt} --symbol-prefix=_"
79	fi
80
81	if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
82		kallsymopt="${kallsymopt} --all-symbols"
83	fi
84
85	if [ -n "${CONFIG_ARM}" ] && [ -n "${CONFIG_PAGE_OFFSET}" ]; then
86		kallsymopt="${kallsymopt} --page-offset=$CONFIG_PAGE_OFFSET"
87	fi
88
89	if [ -n "${CONFIG_X86_64}" ]; then
90		kallsymopt="${kallsymopt} --absolute-percpu"
91	fi
92
93	local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
94		      ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
95
96	${NM} -n ${1} | \
97		scripts/kallsyms ${kallsymopt} | \
98		${CC} ${aflags} -c -o ${2} -x assembler-with-cpp -
99}
100
101# Create map file with all symbols from ${1}
102# See mksymap for additional details
103mksysmap()
104{
105	${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
106}
107
108sortextable()
109{
110	${objtree}/scripts/sortextable ${1}
111}
112
113# Delete output files in case of error
114trap cleanup SIGHUP SIGINT SIGQUIT SIGTERM ERR
115cleanup()
116{
117	rm -f .old_version
118	rm -f .tmp_System.map
119	rm -f .tmp_kallsyms*
120	rm -f .tmp_version
121	rm -f .tmp_vmlinux*
122	rm -f System.map
123	rm -f vmlinux
124	rm -f vmlinux.o
125}
126
127#
128#
129# Use "make V=1" to debug this script
130case "${KBUILD_VERBOSE}" in
131*1*)
132	set -x
133	;;
134esac
135
136if [ "$1" = "clean" ]; then
137	cleanup
138	exit 0
139fi
140
141# We need access to CONFIG_ symbols
142case "${KCONFIG_CONFIG}" in
143*/*)
144	. "${KCONFIG_CONFIG}"
145	;;
146*)
147	# Force using a file from the current directory
148	. "./${KCONFIG_CONFIG}"
149esac
150
151#link vmlinux.o
152info LD vmlinux.o
153modpost_link vmlinux.o
154
155# modpost vmlinux.o to check for section mismatches
156${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
157
158# Update version
159info GEN .version
160if [ ! -r .version ]; then
161	rm -f .version;
162	echo 1 >.version;
163else
164	mv .version .old_version;
165	expr 0$(cat .old_version) + 1 >.version;
166fi;
167
168# final build of init/
169${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
170
171kallsymso=""
172kallsyms_vmlinux=""
173if [ -n "${CONFIG_KALLSYMS}" ]; then
174
175	# kallsyms support
176	# Generate section listing all symbols and add it into vmlinux
177	# It's a three step process:
178	# 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
179	#     but __kallsyms is empty.
180	#     Running kallsyms on that gives us .tmp_kallsyms1.o with
181	#     the right size
182	# 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
183	#     the right size, but due to the added section, some
184	#     addresses have shifted.
185	#     From here, we generate a correct .tmp_kallsyms2.o
186	# 2a) We may use an extra pass as this has been necessary to
187	#     woraround some alignment related bugs.
188	#     KALLSYMS_EXTRA_PASS=1 is used to trigger this.
189	# 3)  The correct ${kallsymso} is linked into the final vmlinux.
190	#
191	# a)  Verify that the System.map from vmlinux matches the map from
192	#     ${kallsymso}.
193
194	kallsymso=.tmp_kallsyms2.o
195	kallsyms_vmlinux=.tmp_vmlinux2
196
197	# step 1
198	vmlinux_link "" .tmp_vmlinux1
199	kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
200
201	# step 2
202	vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
203	kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
204
205	# step 2a
206	if [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
207		kallsymso=.tmp_kallsyms3.o
208		kallsyms_vmlinux=.tmp_vmlinux3
209
210		vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
211
212		kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
213	fi
214fi
215
216info LD vmlinux
217vmlinux_link "${kallsymso}" vmlinux
218
219if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
220	info SORTEX vmlinux
221	sortextable vmlinux
222fi
223
224info SYSMAP System.map
225mksysmap vmlinux System.map
226
227# step a (see comment above)
228if [ -n "${CONFIG_KALLSYMS}" ]; then
229	mksysmap ${kallsyms_vmlinux} .tmp_System.map
230
231	if ! cmp -s System.map .tmp_System.map; then
232		echo >&2 Inconsistent kallsyms data
233		echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
234		cleanup
235		exit 1
236	fi
237fi
238
239# We made a new kernel - delete old version file
240rm -f .old_version
241