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 $(KBUILD_VMLINUX_LIBS). Most are built-in.a files
   8 # from top-level directories in the kernel tree, others are specified in
   9 # arch/$(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.a mm/built-in.a + 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 # Link of vmlinux.o used for section mismatch analysis
  48 # ${1} output file
  49 modpost_link()
  50 {
  51         local objects
  52
  53         objects="--whole-archive                                \
  54                 ${KBUILD_VMLINUX_INIT}                          \
  55                 ${KBUILD_VMLINUX_MAIN}                          \
  56                 --no-whole-archive                              \
  57                 --start-group                                   \
  58                 ${KBUILD_VMLINUX_LIBS}                          \
  59                 --end-group"
  60
  61         ${LD} ${KBUILD_LDFLAGS} -r -o ${1} ${objects}
  62 }
  63
  64 # Link of vmlinux
  65 # ${1} - optional extra .o files
  66 # ${2} - output file
  67 vmlinux_link()
  68 {
  69         local lds="${objtree}/${KBUILD_LDS}"
  70         local objects
  71
  72         if [ "${SRCARCH}" != "um" ]; then
  73                 objects="--whole-archive                        \
  74                         ${KBUILD_VMLINUX_INIT}                  \
  75                         ${KBUILD_VMLINUX_MAIN}                  \
  76                         --no-whole-archive                      \
  77                         --start-group                           \
  78                         ${KBUILD_VMLINUX_LIBS}                  \
  79                         --end-group                             \
  80                         ${1}"
  81
  82                 ${LD} ${KBUILD_LDFLAGS} ${LDFLAGS_vmlinux} -o ${2}      \
  83                         -T ${lds} ${objects}
  84         else
  85                 objects="-Wl,--whole-archive                    \
  86                         ${KBUILD_VMLINUX_INIT}                  \
  87                         ${KBUILD_VMLINUX_MAIN}                  \
  88                         -Wl,--no-whole-archive                  \
  89                         -Wl,--start-group                       \
  90                         ${KBUILD_VMLINUX_LIBS}                  \
  91                         -Wl,--end-group                         \
  92                         ${1}"
  93
  94                 ${CC} ${CFLAGS_vmlinux} -o ${2}                 \
  95                         -Wl,-T,${lds}                           \
  96                         ${objects}                              \
  97                         -lutil -lrt -lpthread
  98                 rm -f linux
  99         fi
 100 }
 101
 102
 103 # Create ${2} .o file with all symbols from the ${1} object file
 104 kallsyms()
 105 {
 106         info KSYM ${2}
 107         local kallsymopt;
 108
 109         if [ -n "${CONFIG_KALLSYMS_ALL}" ]; then
 110                 kallsymopt="${kallsymopt} --all-symbols"
 111         fi
 112
 113         if [ -n "${CONFIG_KALLSYMS_ABSOLUTE_PERCPU}" ]; then
 114                 kallsymopt="${kallsymopt} --absolute-percpu"
 115         fi
 116
 117         if [ -n "${CONFIG_KALLSYMS_BASE_RELATIVE}" ]; then
 118                 kallsymopt="${kallsymopt} --base-relative"
 119         fi
 120
 121         local aflags="${KBUILD_AFLAGS} ${KBUILD_AFLAGS_KERNEL}               \
 122                       ${NOSTDINC_FLAGS} ${LINUXINCLUDE} ${KBUILD_CPPFLAGS}"
 123
 124         local afile="`basename ${2} .o`.S"
 125
 126         ${NM} -n ${1} | scripts/kallsyms ${kallsymopt} > ${afile}
 127         ${CC} ${aflags} -c -o ${2} ${afile}
 128 }
 129
 130 # Create map file with all symbols from ${1}
 131 # See mksymap for additional details
 132 mksysmap()
 133 {
 134         ${CONFIG_SHELL} "${srctree}/scripts/mksysmap" ${1} ${2}
 135 }
 136
 137 sortextable()
 138 {
 139         ${objtree}/scripts/sortextable ${1}
 140 }
 141
 142 # Delete output files in case of error
 143 cleanup()
 144 {
 145         rm -f .tmp_System.map
 146         rm -f .tmp_kallsyms*
 147         rm -f .tmp_vmlinux*
 148         rm -f System.map
 149         rm -f vmlinux
 150         rm -f vmlinux.o
 151 }
 152
 153 on_exit()
 154 {
 155         if [ $? -ne 0 ]; then
 156                 cleanup
 157         fi
 158 }
 159 trap on_exit EXIT
 160
 161 on_signals()
 162 {
 163         exit 1
 164 }
 165 trap on_signals HUP INT QUIT TERM
 166
 167 #
 168 #
 169 # Use "make V=1" to debug this script
 170 case "${KBUILD_VERBOSE}" in
 171 *1*)
 172         set -x
 173         ;;
 174 esac
 175
 176 if [ "$1" = "clean" ]; then
 177         cleanup
 178         exit 0
 179 fi
 180
 181 # We need access to CONFIG_ symbols
 182 case "${KCONFIG_CONFIG}" in
 183 */*)
 184         . "${KCONFIG_CONFIG}"
 185         ;;
 186 *)
 187         # Force using a file from the current directory
 188         . "./${KCONFIG_CONFIG}"
 189 esac
 190
 191 # Update version
 192 info GEN .version
 193 if [ -r .version ]; then
 194         VERSION=$(expr 0$(cat .version) + 1)
 195         echo $VERSION > .version
 196 else
 197         rm -f .version
 198         echo 1 > .version
 199 fi;
 200
 201 # final build of init/
 202 ${MAKE} -f "${srctree}/scripts/Makefile.build" obj=init
 203
 204 #link vmlinux.o
 205 info LD vmlinux.o
 206 modpost_link vmlinux.o
 207
 208 # modpost vmlinux.o to check for section mismatches
 209 ${MAKE} -f "${srctree}/scripts/Makefile.modpost" vmlinux.o
 210
 211 kallsymso=""
 212 kallsyms_vmlinux=""
 213 if [ -n "${CONFIG_KALLSYMS}" ]; then
 214
 215         # kallsyms support
 216         # Generate section listing all symbols and add it into vmlinux
 217         # It's a three step process:
 218         # 1)  Link .tmp_vmlinux1 so it has all symbols and sections,
 219         #     but __kallsyms is empty.
 220         #     Running kallsyms on that gives us .tmp_kallsyms1.o with
 221         #     the right size
 222         # 2)  Link .tmp_vmlinux2 so it now has a __kallsyms section of
 223         #     the right size, but due to the added section, some
 224         #     addresses have shifted.
 225         #     From here, we generate a correct .tmp_kallsyms2.o
 226         # 3)  That link may have expanded the kernel image enough that
 227         #     more linker branch stubs / trampolines had to be added, which
 228         #     introduces new names, which further expands kallsyms. Do another
 229         #     pass if that is the case. In theory it's possible this results
 230         #     in even more stubs, but unlikely.
 231         #     KALLSYMS_EXTRA_PASS=1 may also used to debug or work around
 232         #     other bugs.
 233         # 4)  The correct ${kallsymso} is linked into the final vmlinux.
 234         #
 235         # a)  Verify that the System.map from vmlinux matches the map from
 236         #     ${kallsymso}.
 237
 238         kallsymso=.tmp_kallsyms2.o
 239         kallsyms_vmlinux=.tmp_vmlinux2
 240
 241         # step 1
 242         vmlinux_link "" .tmp_vmlinux1
 243         kallsyms .tmp_vmlinux1 .tmp_kallsyms1.o
 244
 245         # step 2
 246         vmlinux_link .tmp_kallsyms1.o .tmp_vmlinux2
 247         kallsyms .tmp_vmlinux2 .tmp_kallsyms2.o
 248
 249         # step 3
 250         size1=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms1.o)
 251         size2=$(${CONFIG_SHELL} "${srctree}/scripts/file-size.sh" .tmp_kallsyms2.o)
 252
 253         if [ $size1 -ne $size2 ] || [ -n "${KALLSYMS_EXTRA_PASS}" ]; then
 254                 kallsymso=.tmp_kallsyms3.o
 255                 kallsyms_vmlinux=.tmp_vmlinux3
 256
 257                 vmlinux_link .tmp_kallsyms2.o .tmp_vmlinux3
 258
 259                 kallsyms .tmp_vmlinux3 .tmp_kallsyms3.o
 260         fi
 261 fi
 262
 263 info LD vmlinux
 264 vmlinux_link "${kallsymso}" vmlinux
 265
 266 if [ -n "${CONFIG_BUILDTIME_EXTABLE_SORT}" ]; then
 267         info SORTEX vmlinux
 268         sortextable vmlinux
 269 fi
 270
 271 info SYSMAP System.map
 272 mksysmap vmlinux System.map
 273
 274 # step a (see comment above)
 275 if [ -n "${CONFIG_KALLSYMS}" ]; then
 276         mksysmap ${kallsyms_vmlinux} .tmp_System.map
 277
 278         if ! cmp -s System.map .tmp_System.map; then
 279                 echo >&2 Inconsistent kallsyms data
 280                 echo >&2 Try "make KALLSYMS_EXTRA_PASS=1" as a workaround
 281                 exit 1
 282         fi
 283 fi