Root/scripts/link-vmlinux.sh

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

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