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) and $(KBUILD_VMLINUX_LIBS). Most are built-in.o files
   7 # from top-level directories in the kernel tree, others are specified in
   8 # arch/$(ARCH)/Makefile. Ordering when linking is important, and
   9 # $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
  10 # which are linked conditionally (not within --whole-archive), and do not
  11 # require symbol indexes added.
  12 #
  13 # vmlinux
  14 #   ^
  15 #   |
  16 #   +-< $(KBUILD_VMLINUX_INIT)
  17 #   |   +--< init/version.o + more
  18 #   |
  19 #   +--< $(KBUILD_VMLINUX_MAIN)
  20 #   |    +--< drivers/built-in.o mm/built-in.o + more
  21 #   |
  22 #   +--< $(KBUILD_VMLINUX_LIBS)
  23 #   |    +--< lib/lib.a + more
  24 #   |
  25 #   +-< ${kallsymso} (see description in KALLSYMS section)
  26 #
  27 # vmlinux version (uname -v) cannot be updated during normal
  28 # descending-into-subdirs phase since we do not yet know if we need to
  29 # update vmlinux.
  30 # Therefore this step is delayed until just before final link of vmlinux.
  31 #
  32 # System.map is generated to document addresses of all kernel symbols
  33
  34 # Error out on error
  35 set -e
  36
  37 # Nice output in kbuild format
  38 # Will be supressed by "make -s"
  39 info()
  40 {
  41         if [ "${quiet}" != "silent_" ]; then
  42                 printf "  %-7s %s\n" ${1} ${2}
  43         fi
  44 }
  45
  46 # Thin archive build here makes a final archive with symbol table and indexes
  47 # from vmlinux objects INIT and MAIN, which can be used as input to linker.
  48 # KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
  49 # added.
  50 #
  51 # Traditional incremental style of link does not require this step
  52 #
  53 # built-in.o output file
  54 #
  55 archive_builtin()
  56 {
  57         if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
  58                 info AR built-in.o
  59                 rm -f built-in.o;
  60                 ${AR} rcsTP${KBUILD_ARFLAGS} built-in.o                 \
  61                                         ${KBUILD_VMLINUX_INIT}          \
  62                                         ${KBUILD_VMLINUX_MAIN}
  63         fi
  64 }
  65
  66 # Link of vmlinux.o used for section mismatch analysis
  67 # ${1} output file
  68 modpost_link()
  69 {
  70         local objects
  71
  72         if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
  73                 objects="--whole-archive                                \
  74                         built-in.o                                      \
  75                         --no-whole-archive                              \
  76                         --start-group                                   \
  77                         ${KBUILD_VMLINUX_LIBS}                          \
  78                         --end-group"
  79         else
  80                 objects="${KBUILD_VMLINUX_INIT}                         \
  81                         --start-group                                   \
  82                         ${KBUILD_VMLINUX_MAIN}                          \
  83                         ${KBUILD_VMLINUX_LIBS}                          \
  84                         --end-group"
  85         fi
  86         ${LD} ${LDFLAGS} -r -o ${1} ${objects}
  87 }
  88
  89 # Link of vmlinux
  90 # ${1} - optional extra .o files
  91 # ${2} - output file
  92 vmlinux_link()
  93 {
  94         local lds="${objtree}/${KBUILD_LDS}"
  95         local objects
  96
  97         if [ "${SRCARCH}" != "um" ]; then
  98                 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
  99                         objects="--whole-archive                        \
 100                                 built-in.o                              \
 101                                 --no-whole-archive                      \
 102                                 --start-group                           \
 103                                 ${KBUILD_VMLINUX_LIBS}                  \
 104                                 --end-group                             \
 105                                 ${1}"
 106                 else
 107                         objects="${KBUILD_VMLINUX_INIT}                 \
 108                                 --start-group                           \
 109                                 ${KBUILD_VMLINUX_MAIN}                  \
 110                                 ${KBUILD_VMLINUX_LIBS}                  \
 111                                 --end-group                             \
 112                                 ${1}"
 113                 fi
 114
 115                 ${LD} ${LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}             \
 116                         -T ${lds} ${objects}
 117         else
 118                 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
 119                         objects="-Wl,--whole-archive                    \
 120                                 built-in.o                              \
 121                                 -Wl,--no-whole-archive                  \
 122                                 -Wl,--start-group                       \
 123                                 ${KBUILD_VMLINUX_LIBS}                  \
 124                                 -Wl,--end-group                         \
 125                                 ${1}"
 126                 else
 127                         objects="${KBUILD_VMLINUX_INIT}                 \
 128                                 -Wl,--start-group                       \
 129                                 ${KBUILD_VMLINUX_MAIN}                  \
 130                                 ${KBUILD_VMLINUX_LIBS}                  \
 131                                 -Wl,--end-group                         \
 132                                 ${1}"
 133                 fi
 134
 135                 ${CC} ${CFLAGS_vmlinux} -o ${2}                         \
 136                         -Wl,-T,${lds}                                   \
 137                         ${objects}                                      \
 138                         -lutil -lrt -lpthread
 139                 rm -f linux
 140         fi
 141 }
 142
 143
 144 # Create ${2} .o file with all symbols from the ${1} object file
 145 kallsyms()
 146 {
 147         info KSYM ${2}
 148         local kallsymopt;
 149
 150         if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
 151                 kallsymopt="${kallsymopt} --symbol-prefix=_"
 152         fi
 153
 154         if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
 155                 kallsymopt="${kallsymopt} --all-symbols"
 156         fi
 157
 158         if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
 159                 kallsymopt="${kallsymopt} --absolute-percpu"
 160         fi
 161
 162         if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
 163                 kallsymopt="${kallsymopt} --base-relative"
 164         fi
 165
 166         local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
 167                       ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
 168
 169         local afile="`basename ${2} .o`.S"
 170
 171         ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
 172         ${CC} ${aflags} -c -o ${2} ${afile}
 173 }
 174
 175 # Create map file with all symbols from ${1}
 176 # See mksymap for additional details
 177 mksysmap()
 178 {
 179         ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 180 }
 181
 182 sortextable()
 183 {
 184         ${objtree}/scripts/sortextable ${1}
 185 }
 186
 187 # Delete output files in case of error
 188 cleanup()
 189 {
 190         rm -f .old_version
 191         rm -f .tmp_System.map
 192         rm -f .tmp_kallsyms*
 193         rm -f .tmp_version
 194         rm -f .tmp_vmlinux*
 195         rm -f built-in.o
 196         rm -f System.map
 197         rm -f vmlinux
 198         rm -f vmlinux.o
 199 }
 200
 201 on_exit()
 202 {
 203         if [ $? -ne 0 ]; then
 204                 cleanup
 205         fi
 206 }
 207 trap on_exit EXIT
 208
 209 on_signals()
 210 {
 211         exit 1
 212 }
 213 trap on_signals HUP INT QUIT TERM
 214
 215 #
 216 #
 217 # Use "make V=1" to debug this script
 218 case "${KBUILD_VERBOSE}" in
 219 *1*)
 220         set -x
 221         ;;
 222 esac
 223
 224 if [ "$1" = "clean" ]; then
 225         cleanup
 226         exit 0
 227 fi
 228
 229 # We need access to CONFIG_ symbols
 230 case "${KCONFIG_CONFIG}" in
 231 */*)
 232         . "${KCONFIG_CONFIG}"
 233         ;;
 234 *)
 235         # Force using a file from the current directory
 236         . "./${KCONFIG_CONFIG}"
 237 esac
 238
 239 # Update version
 240 info GEN .version
 241 if [ ! -r .version ]; then
 242         rm -f .version;
 243         echo 1 >.version;
 244 else
 245         mv .version .old_version;
 246         expr 0$(cat .old_version) + 1 >.version;
 247 fi;
 248
 249 # final build of init/
 250 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GCC_PLUGINS_CFLAGS}"
 251
 252 archive_builtin
 253
 254 #link vmlinux.o
 255 info LD vmlinux.o
 256 modpost_link vmlinux.o
 257
 258 # modpost vmlinux.o to check for section mismatches
 259 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 260
 261 kallsymso=""
 262 kallsyms_vmlinux=""
 263 if [ -n "${CONFIG_KALLSYMS}" ]; then
 264
 265         # kallsyms support
 266         # Generate section listing all symbols and add it into vmlinux
 267         # It's a three step process:
 268         # 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
 269         #     but __kallsyms is empty.
 270         #     Running kallsyms on that gives us .tmp_kallsyms1.o with
 271         #     the right size
 272         # 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
 273         #     the right size, but due to the added section, some
 274         #     addresses have shifted.
 275         #     From here, we generate a correct .tmp_kallsyms2.o
 276         # 3)  That link may have expanded the kernel image enough that
 277         #     more linker branch stubs / trampolines had to be added, which
 278         #     introduces new names, which further expands kallsyms. Do another
 279         #     pass if that is the case. In theory it's possible this results
 280         #     in even more stubs, but unlikely.
 281         #     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
 282         #     other bugs.
 283         # 4)  The correct ${kallsymso} is linked into the final vmlinux.
 284         #
 285         # a)  Verify that the System.map from vmlinux matches the map from
 286         #     ${kallsymso}.
 287
 288         kallsymso=.tmp_kallsyms2.o
 289         kallsyms_vmlinux=.tmp_vmlinux2
 290
 291         # step 1
 292         vmlinux_link "" .tmp_vmlinux1
 293         kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
 294
 295         # step 2
 296         vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
 297         kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
 298
 299         # step 3
 300         size1=$(stat -c "%s" .tmp_kallsyms1.o)
 301         size2=$(stat -c "%s" .tmp_kallsyms2.o)
 302
 303         if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
 304                 kallsymso=.tmp_kallsyms3.o
 305                 kallsyms_vmlinux=.tmp_vmlinux3
 306
 307                 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
 308
 309                 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
 310         fi
 311 fi
 312
 313 info LD vmlinux
 314 vmlinux_link "${kallsymso}" vmlinux
 315
 316 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
 317         info SORTEX vmlinux
 318         sortextable vmlinux
 319 fi
 320
 321 info SYSMAP System.map
 322 mksysmap vmlinux System.map
 323
 324 # step a (see comment above)
 325 if [ -n "${CONFIG_KALLSYMS}" ]; then
 326         mksysmap ${kallsyms_vmlinux} .tmp_System.map
 327
 328         if ! cmp -s System.map .tmp_System.map; then
 329                 echo >&2 Inconsistent kallsyms data
 330                 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
 331                 exit 1
 332         fi
 333 fi
 334
 335 # We made a new kernel - delete old version file
 336 rm -f .old_version