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} ${2}
  37         fi
  38 }
  39
  40 # Thin archive build here makes a final archive with
  41 # symbol table and indexes from vmlinux objects, which can be
  42 # used as input to linker.
  43 #
  44 # Traditional incremental style of link does not require this step
  45 #
  46 # built-in.o output file
  47 #
  48 archive_builtin()
  49 {
  50         if [ -n "${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 # ${1} output file
  61 modpost_link()
  62 {
  63         local objects
  64
  65         if [ -n "${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 # ${2} - output file
  79 vmlinux_link()
  80 {
  81         local lds="${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
 118 kallsyms()
 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
 150 mksysmap()
 151 {
 152         ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 153 }
 154
 155 sortextable()
 156 {
 157         ${objtree}/scripts/sortextable ${1}
 158 }
 159
 160 # Delete output files in case of error
 161 cleanup()
 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
 174 on_exit()
 175 {
 176         if [ $? -ne 0 ]; then
 177                 cleanup
 178         fi
 179 }
 180 trap on_exit EXIT
 181
 182 on_signals()
 183 {
 184         exit 1
 185 }
 186 trap on_signals HUP INT QUIT TERM
 187
 188 #
 189 #
 190 # Use "make V=1" to debug this script
 191 case "${KBUILD_VERBOSE}" in
 192 *1*)
 193         set -x
 194         ;;
 195 esac
 196
 197 if [ "$1" = "clean" ]; then
 198         cleanup
 199         exit 0
 200 fi
 201
 202 # We need access to CONFIG_ symbols
 203 case "${KCONFIG_CONFIG}" in
 204 */*)
 205         . "${KCONFIG_CONFIG}"
 206         ;;
 207 *)
 208         # Force using a file from the current directory
 209         . "./${KCONFIG_CONFIG}"
 210 esac
 211
 212 # Update version
 213 info GEN .version
 214 if [ ! -r .version ]; then
 215         rm -f .version;
 216         echo 1 >.version;
 217 else
 218         mv .version .old_version;
 219         expr 0$(cat .old_version) + 1 >.version;
 220 fi;
 221
 222 # final build of init/
 223 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GCC_PLUGINS_CFLAGS}"
 224
 225 archive_builtin
 226
 227 #link vmlinux.o
 228 info LD vmlinux.o
 229 modpost_link vmlinux.o
 230
 231 # modpost vmlinux.o to check for section mismatches
 232 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 233
 234 kallsymso=""
 235 kallsyms_vmlinux=""
 236 if [ -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
 284 fi
 285
 286 info LD vmlinux
 287 vmlinux_link "${kallsymso}" vmlinux
 288
 289 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
 290         info SORTEX vmlinux
 291         sortextable vmlinux
 292 fi
 293
 294 info SYSMAP System.map
 295 mksysmap vmlinux System.map
 296
 297 # step a (see comment above)
 298 if [ -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
 306 fi
 307
 308 # We made a new kernel - delete old version file
 309 rm -f .old_version