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