linux/scripts/link-vmlinux.sh
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   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