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 #   +-< ${kallsymso} (see description in KALLSYMS section)
  20 #
  21 # vmlinux version (uname -v) cannot be updated during normal
  22 # descending-into-subdirs phase since we do not yet know if we need to
  23 # update vmlinux.
  24 # Therefore this step is delayed until just before final link of vmlinux.
  25 #
  26 # System.map is generated to document addresses of all kernel symbols
  27
  28 # Error out on error
  29 set -e
  30
  31 # Nice output in kbuild format
  32 # Will be supressed by "make -s"
  33 info()
  34 {
  35         if [ "${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
  42 modpost_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 # ${2} - output file
  51 vmlinux_link()
  52 {
  53         local lds="${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                                        \
  59                                 ${KBUILD_VMLINUX_MAIN}                       \
  60                                 ${KBUILD_VMLINUX_PIE}                        \
  61                         --end-group ${1}
  62         else
  63                 ${CC} ${CFLAGS_vmlinux} -o ${2}                              \
  64                         -Wl,-T,${lds} ${KBUILD_VMLINUX_INIT}                 \
  65                         -Wl,--start-group                                    \
  66                                  ${KBUILD_VMLINUX_MAIN}                      \
  67                                  ${KBUILD_VMLINUX_PIE}                       \
  68                         -Wl,--end-group                                      \
  69                         -lutil ${1}
  70                 rm -f linux
  71         fi
  72 }
  73
  74
  75 # Create ${2} .o file with all symbols from the ${1} object file
  76 kallsyms()
  77 {
  78         info KSYM ${2}
  79         local kallsymopt;
  80
  81         if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
  82                 kallsymopt="${kallsymopt} --symbol-prefix=_"
  83         fi
  84
  85         if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
  86                 kallsymopt="${kallsymopt} --all-symbols"
  87         fi
  88
  89         kallsymopt="${kallsymopt} --page-offset=$CONFIG_PAGE_OFFSET"
  90
  91         local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
  92                       ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
  93
  94         ${NM} -n ${1} | \
  95                 scripts/kallsyms ${kallsymopt} | \
  96                 ${CC} ${aflags} -c -o ${2} -x assembler-with-cpp -
  97 }
  98
  99 # Create map file with all symbols from ${1}
 100 # See mksymap for additional details
 101 mksysmap()
 102 {
 103         ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 104 }
 105
 106 sortextable()
 107 {
 108         ${objtree}/scripts/sortextable ${1}
 109 }
 110
 111 # Delete output files in case of error
 112 trap cleanup SIGHUP SIGINT SIGQUIT SIGTERM ERR
 113 cleanup()
 114 {
 115         rm -f .old_version
 116         rm -f .tmp_System.map
 117         rm -f .tmp_kallsyms*
 118         rm -f .tmp_version
 119         rm -f .tmp_vmlinux*
 120         rm -f System.map
 121         rm -f vmlinux
 122         rm -f vmlinux.o
 123 }
 124
 125 #
 126 #
 127 # Use "make V=1" to debug this script
 128 case "${KBUILD_VERBOSE}" in
 129 *1*)
 130         set -x
 131         ;;
 132 esac
 133
 134 if [ "$1" = "clean" ]; then
 135         cleanup
 136         exit 0
 137 fi
 138
 139 # We need access to CONFIG_ symbols
 140 case "${KCONFIG_CONFIG}" in
 141 */*)
 142         . "${KCONFIG_CONFIG}"
 143         ;;
 144 *)
 145         # Force using a file from the current directory
 146         . "./${KCONFIG_CONFIG}"
 147 esac
 148
 149 #link vmlinux.o
 150 info LD vmlinux.o
 151 modpost_link vmlinux.o
 152 # modpost vmlinux.o to check for section mismatches
 153 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 154
 155 if [ -n "${CONFIG_PIE}" ]; then
 156         ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=pie
 157 fi
 158
 159 # Update version
 160 info GEN .version
 161 if [ ! -r .version ]; then
 162         rm -f .version;
 163         echo 1 >.version;
 164 else
 165         mv .version .old_version;
 166         expr 0$(cat .old_version) + 1 >.version;
 167 fi;
 168
 169 # final build of init/
 170 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
 171
 172 kallsymso=""
 173 kallsyms_vmlinux=""
 174 if [ -n "${CONFIG_KALLSYMS}" ]; then
 175
 176         # kallsyms support
 177         # Generate section listing all symbols and add it into vmlinux
 178         # It's a three step process:
 179         # 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
 180         #     but __kallsyms is empty.
 181         #     Running kallsyms on that gives us .tmp_kallsyms1.o with
 182         #     the right size
 183         # 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
 184         #     the right size, but due to the added section, some
 185         #     addresses have shifted.
 186         #     From here, we generate a correct .tmp_kallsyms2.o
 187         # 2a) We may use an extra pass as this has been necessary to
 188         #     woraround some alignment related bugs.
 189         #     KALLSYMS_EXTRA_PASS=1 is used to trigger this.
 190         # 3)  The correct ${kallsymso} is linked into the final vmlinux.
 191         #
 192         # a)  Verify that the System.map from vmlinux matches the map from
 193         #     ${kallsymso}.
 194
 195         kallsymso=.tmp_kallsyms2.o
 196         kallsyms_vmlinux=.tmp_vmlinux2
 197
 198         # step 1
 199         vmlinux_link "" .tmp_vmlinux1
 200         kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
 201
 202         # step 2
 203         vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
 204         kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
 205
 206         # step 2a
 207         if [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
 208                 kallsymso=.tmp_kallsyms3.o
 209                 kallsyms_vmlinux=.tmp_vmlinux3
 210
 211                 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
 212
 213                 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
 214         fi
 215 fi
 216
 217 info LD vmlinux
 218 vmlinux_link "${kallsymso}" vmlinux
 219
 220 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
 221         info SORTEX vmlinux
 222         sortextable vmlinux
 223 fi
 224
 225 info SYSMAP System.map
 226 mksysmap vmlinux System.map
 227
 228 # step a (see comment above)
 229 if [ -n "${CONFIG_KALLSYMS}" ]; then
 230         mksysmap ${kallsyms_vmlinux} .tmp_System.map
 231
 232         if ! cmp -s System.map .tmp_System.map; then
 233                 echo >&2 Inconsistent kallsyms data
 234                 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
 235                 cleanup
 236                 exit 1
 237         fi
 238 fi
 239
 240 # We made a new kernel - delete old version file
 241 rm -f .old_version