scripts/link-vmlinux.sh

   1 #!/bin/sh
   2 # SPDX-License-Identifier: GPL-2.0
   3 #
   4 # link vmlinux
   5 #
   6 # vmlinux is linked from the objects selected by $(KBUILD_VMLINUX_INIT) and
   7 # $(KBUILD_VMLINUX_MAIN) and $(KBUILD_VMLINUX_LIBS). Most are built-in.o files
   8 # from top-level directories in the kernel tree, others are specified in
   9 # arch/$(ARCH)/Makefile. Ordering when linking is important, and
  10 # $(KBUILD_VMLINUX_INIT) must be first. $(KBUILD_VMLINUX_LIBS) are archives
  11 # which are linked conditionally (not within --whole-archive), and do not
  12 # require symbol indexes added.
  13 #
  14 # vmlinux
  15 #   ^
  16 #   |
  17 #   +-< $(KBUILD_VMLINUX_INIT)
  18 #   |   +--< init/version.o + more
  19 #   |
  20 #   +--< $(KBUILD_VMLINUX_MAIN)
  21 #   |    +--< drivers/built-in.o mm/built-in.o + more
  22 #   |
  23 #   +--< $(KBUILD_VMLINUX_LIBS)
  24 #   |    +--< lib/lib.a + more
  25 #   |
  26 #   +-< ${kallsymso} (see description in KALLSYMS section)
  27 #
  28 # vmlinux version (uname -v) cannot be updated during normal
  29 # descending-into-subdirs phase since we do not yet know if we need to
  30 # update vmlinux.
  31 # Therefore this step is delayed until just before final link of vmlinux.
  32 #
  33 # System.map is generated to document addresses of all kernel symbols
  34
  35 # Error out on error
  36 set -e
  37
  38 # Nice output in kbuild format
  39 # Will be supressed by "make -s"
  40 info()
  41 {
  42         if [ "${quiet}" != "silent_" ]; then
  43                 printf "  %-7s %s\n" ${1} ${2}
  44         fi
  45 }
  46
  47 # Thin archive build here makes a final archive with symbol table and indexes
  48 # from vmlinux objects INIT and MAIN, which can be used as input to linker.
  49 # KBUILD_VMLINUX_LIBS archives should already have symbol table and indexes
  50 # added.
  51 #
  52 # Traditional incremental style of link does not require this step
  53 #
  54 # built-in.o output file
  55 #
  56 archive_builtin()
  57 {
  58         if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
  59                 info AR built-in.o
  60                 rm -f built-in.o;
  61                 ${AR} rcsTP${KBUILD_ARFLAGS} built-in.o                 \
  62                                         ${KBUILD_VMLINUX_INIT}          \
  63                                         ${KBUILD_VMLINUX_MAIN}
  64
  65                 if [ -n "${CONFIG_LTO_CLANG}" ]; then
  66                         mv -f built-in.o built-in.o.tmp
  67                         ${LLVM_AR} rcsT${KBUILD_ARFLAGS} built-in.o $(${AR} t built-in.o.tmp)
  68                         rm -f built-in.o.tmp
  69                 fi
  70         fi
  71 }
  72
  73 # If CONFIG_LTO_CLANG is selected, collect generated symbol versions into
  74 # .tmp_symversions
  75 modversions()
  76 {
  77         if [ -z "${CONFIG_LTO_CLANG}" ]; then
  78                 return
  79         fi
  80
  81         if [ -z "${CONFIG_MODVERSIONS}" ]; then
  82                 return
  83         fi
  84
  85         rm -f .tmp_symversions
  86
  87         for a in built-in.o ${KBUILD_VMLINUX_LIBS}; do
  88                 for o in $(${AR} t $a); do
  89                         if [ -f ${o}.symversions ]; then
  90                                 cat ${o}.symversions >> .tmp_symversions
  91                         fi
  92                 done
  93         done
  94
  95         echo "-T .tmp_symversions"
  96 }
  97
  98 # Link of vmlinux.o used for section mismatch analysis
  99 # ${1} output file
 100 modpost_link()
 101 {
 102         local objects
 103
 104         if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
 105                 objects="--whole-archive                                \
 106                         built-in.o                                      \
 107                         --no-whole-archive                              \
 108                         --start-group                                   \
 109                         ${KBUILD_VMLINUX_LIBS}                          \
 110                         --end-group"
 111         else
 112                 objects="${KBUILD_VMLINUX_INIT}                         \
 113                         --start-group                                   \
 114                         ${KBUILD_VMLINUX_MAIN}                          \
 115                         ${KBUILD_VMLINUX_LIBS}                          \
 116                         --end-group"
 117         fi
 118
 119         if [ -n "${CONFIG_LTO_CLANG}" ]; then
 120                 # This might take a while, so indicate that we're doing
 121                 # an LTO link
 122                 info LTO vmlinux.o
 123         else
 124                 info LD vmlinux.o
 125         fi
 126
 127         ${LD} ${LDFLAGS} -r -o ${1} $(modversions) ${objects}
 128 }
 129
 130 # If CONFIG_LTO_CLANG is selected, we postpone running recordmcount until
 131 # we have compiled LLVM IR to an object file.
 132 recordmcount()
 133 {
 134         if [ -z "${CONFIG_LTO_CLANG}" ]; then
 135                 return
 136         fi
 137
 138         if [ -n "${CONFIG_FTRACE_MCOUNT_RECORD}" ]; then
 139                 scripts/recordmcount ${RECORDMCOUNT_FLAGS} $*
 140         fi
 141 }
 142
 143 # Link of vmlinux
 144 # ${1} - optional extra .o files
 145 # ${2} - output file
 146 vmlinux_link()
 147 {
 148         local lds="${objtree}/${KBUILD_LDS}"
 149         local objects
 150
 151         if [ "${SRCARCH}" != "um" ]; then
 152                 local ld=${LD}
 153                 local ldflags="${LDFLAGS} ${LDFLAGS_vmlinux}"
 154
 155                 if [ -n "${LDFINAL_vmlinux}" ]; then
 156                         ld=${LDFINAL_vmlinux}
 157                         ldflags="${LDFLAGS_FINAL_vmlinux} ${LDFLAGS_vmlinux}"
 158                 fi
 159
 160                 if [[ -n "${CONFIG_THIN_ARCHIVES}" && -z "${CONFIG_LTO_CLANG}" ]]; then
 161                         objects="--whole-archive                        \
 162                                 built-in.o                              \
 163                                 --no-whole-archive                      \
 164                                 --start-group                           \
 165                                 ${KBUILD_VMLINUX_LIBS}                  \
 166                                 --end-group                             \
 167                                 ${1}"
 168                 else
 169                         objects="${KBUILD_VMLINUX_INIT}                 \
 170                                 --start-group                           \
 171                                 ${KBUILD_VMLINUX_MAIN}                  \
 172                                 ${KBUILD_VMLINUX_LIBS}                  \
 173                                 --end-group                             \
 174                                 ${1}"
 175                 fi
 176
 177                 ${ld} ${ldflags} -o ${2} -T ${lds} ${objects}
 178         else
 179                 if [ -n "${CONFIG_THIN_ARCHIVES}" ]; then
 180                         objects="-Wl,--whole-archive                    \
 181                                 built-in.o                              \
 182                                 -Wl,--no-whole-archive                  \
 183                                 -Wl,--start-group                       \
 184                                 ${KBUILD_VMLINUX_LIBS}                  \
 185                                 -Wl,--end-group                         \
 186                                 ${1}"
 187                 else
 188                         objects="${KBUILD_VMLINUX_INIT}                 \
 189                                 -Wl,--start-group                       \
 190                                 ${KBUILD_VMLINUX_MAIN}                  \
 191                                 ${KBUILD_VMLINUX_LIBS}                  \
 192                                 -Wl,--end-group                         \
 193                                 ${1}"
 194                 fi
 195
 196                 ${CC} ${CFLAGS_vmlinux} -o ${2}                         \
 197                         -Wl,-T,${lds}                                   \
 198                         ${objects}                                      \
 199                         -lutil -lrt -lpthread
 200                 rm -f linux
 201         fi
 202 }
 203
 204 # Create ${2} .o file with all symbols from the ${1} object file
 205 kallsyms()
 206 {
 207         info KSYM ${2}
 208         local kallsymopt;
 209
 210         if [ -n "${CONFIG_HAVE_UNDERSCORE_SYMBOL_PREFIX}" ]; then
 211                 kallsymopt="${kallsymopt} --symbol-prefix=_"
 212         fi
 213
 214         if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
 215                 kallsymopt="${kallsymopt} --all-symbols"
 216         fi
 217
 218         if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
 219                 kallsymopt="${kallsymopt} --absolute-percpu"
 220         fi
 221
 222         if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
 223                 kallsymopt="${kallsymopt} --base-relative"
 224         fi
 225
 226         local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
 227                       ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
 228
 229         local afile="`basename ${2} .o`.S"
 230
 231         ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
 232         ${CC} ${aflags} -c -o ${2} ${afile}
 233 }
 234
 235 # Create map file with all symbols from ${1}
 236 # See mksymap for additional details
 237 mksysmap()
 238 {
 239         ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 240 }
 241
 242 sortextable()
 243 {
 244         ${objtree}/scripts/sortextable ${1}
 245 }
 246
 247 # Delete output files in case of error
 248 cleanup()
 249 {
 250         rm -f .old_version
 251         rm -f .tmp_System.map
 252         rm -f .tmp_kallsyms*
 253         rm -f .tmp_version
 254         rm -f .tmp_symversions
 255         rm -f .tmp_vmlinux*
 256         rm -f built-in.o
 257         rm -f System.map
 258         rm -f vmlinux
 259         rm -f vmlinux.o
 260 }
 261
 262 on_exit()
 263 {
 264         if [ $? -ne 0 ]; then
 265                 cleanup
 266         fi
 267 }
 268 trap on_exit EXIT
 269
 270 on_signals()
 271 {
 272         exit 1
 273 }
 274 trap on_signals HUP INT QUIT TERM
 275
 276 #
 277 #
 278 # Use "make V=1" to debug this script
 279 case "${KBUILD_VERBOSE}" in
 280 *1*)
 281         set -x
 282         ;;
 283 esac
 284
 285 if [ "$1" = "clean" ]; then
 286         cleanup
 287         exit 0
 288 fi
 289
 290 # We need access to CONFIG_ symbols
 291 case "${KCONFIG_CONFIG}" in
 292 */*)
 293         . "${KCONFIG_CONFIG}"
 294         ;;
 295 *)
 296         # Force using a file from the current directory
 297         . "./${KCONFIG_CONFIG}"
 298 esac
 299
 300 # Update version
 301 info GEN .version
 302 if [ ! -r .version ]; then
 303         rm -f .version;
 304         echo 1 >.version;
 305 else
 306         mv .version .old_version;
 307         expr 0$(cat .old_version) + 1 >.version;
 308 fi;
 309
 310 # final build of init/
 311 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init GCC_PLUGINS_CFLAGS="${GCC_PLUGINS_CFLAGS}"
 312
 313 archive_builtin
 314
 315 #link vmlinux.o
 316 modpost_link vmlinux.o
 317
 318 # modpost vmlinux.o to check for section mismatches
 319 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 320
 321 if [ -n "${CONFIG_LTO_CLANG}" ]; then
 322         # Re-use vmlinux.o, so we can avoid the slow LTO link step in
 323         # vmlinux_link
 324         KBUILD_VMLINUX_INIT=
 325         KBUILD_VMLINUX_MAIN=vmlinux.o
 326         KBUILD_VMLINUX_LIBS=
 327
 328         # Call recordmcount if needed
 329         recordmcount vmlinux.o
 330 fi
 331
 332 kallsymso=""
 333 kallsyms_vmlinux=""
 334 if [ -n "${CONFIG_KALLSYMS}" ]; then
 335
 336         # kallsyms support
 337         # Generate section listing all symbols and add it into vmlinux
 338         # It's a three step process:
 339         # 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
 340         #     but __kallsyms is empty.
 341         #     Running kallsyms on that gives us .tmp_kallsyms1.o with
 342         #     the right size
 343         # 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
 344         #     the right size, but due to the added section, some
 345         #     addresses have shifted.
 346         #     From here, we generate a correct .tmp_kallsyms2.o
 347         # 3)  That link may have expanded the kernel image enough that
 348         #     more linker branch stubs / trampolines had to be added, which
 349         #     introduces new names, which further expands kallsyms. Do another
 350         #     pass if that is the case. In theory it's possible this results
 351         #     in even more stubs, but unlikely.
 352         #     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
 353         #     other bugs.
 354         # 4)  The correct ${kallsymso} is linked into the final vmlinux.
 355         #
 356         # a)  Verify that the System.map from vmlinux matches the map from
 357         #     ${kallsymso}.
 358
 359         kallsymso=.tmp_kallsyms2.o
 360         kallsyms_vmlinux=.tmp_vmlinux2
 361
 362         # step 1
 363         vmlinux_link "" .tmp_vmlinux1
 364         kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
 365
 366         # step 2
 367         vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
 368         kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
 369
 370         # step 3
 371         size1=$(stat -c "%s" .tmp_kallsyms1.o)
 372         size2=$(stat -c "%s" .tmp_kallsyms2.o)
 373
 374         if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
 375                 kallsymso=.tmp_kallsyms3.o
 376                 kallsyms_vmlinux=.tmp_vmlinux3
 377
 378                 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
 379
 380                 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
 381         fi
 382 fi
 383
 384 info LD vmlinux
 385 vmlinux_link "${kallsymso}" vmlinux
 386
 387 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
 388         info SORTEX vmlinux
 389         sortextable vmlinux
 390 fi
 391
 392 info SYSMAP System.map
 393 mksysmap vmlinux System.map
 394
 395 # step a (see comment above)
 396 if [ -n "${CONFIG_KALLSYMS}" ]; then
 397         mksysmap ${kallsyms_vmlinux} .tmp_System.map
 398
 399         if ! cmp -s System.map .tmp_System.map; then
 400                 echo >&2 Inconsistent kallsyms data
 401                 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
 402                 exit 1
 403         fi
 404 fi
 405
 406 # We made a new kernel - delete old version file
 407 rm -f .old_version