arch/powerpc/kernel/prom_init_check.sh

   1 #!/bin/sh
   2 #
   3 # Copyright © 2008 IBM Corporation
   4 #
   5 # This program is free software; you can redistribute it and/or
   6 # modify it under the terms of the GNU General Public License
   7 # as published by the Free Software Foundation; either version
   8 # 2 of the License, or (at your option) any later version.
   9
  10 # This script checks prom_init.o to see what external symbols it
  11 # is using, if it finds symbols not in the whitelist it returns
  12 # an error. The point of this is to discourage people from
  13 # intentionally or accidentally adding new code to prom_init.c
  14 # which has side effects on other parts of the kernel.
  15
  16 # If you really need to reference something from prom_init.o add
  17 # it to the list below:
  18
  19 WHITELIST="add_reloc_offset __bss_start __bss_stop copy_and_flush
  20 _end enter_prom memcpy memset reloc_offset __secondary_hold
  21 __secondary_hold_acknowledge __secondary_hold_spinloop __start
  22 strcmp strcpy strlcpy strlen strncmp strstr logo_linux_clut224
  23 reloc_got2 kernstart_addr memstart_addr linux_banner"
  24
  25 NM="$1"
  26 OBJ="$2"
  27
  28 ERROR=0
  29
  30 for UNDEF in $($NM -u $OBJ | awk '{print $2}')
  31 do
  32         # On 64-bit nm gives us the function descriptors, which have
  33         # a leading . on the name, so strip it off here.
  34         UNDEF="${UNDEF#.}"
  35
  36         if [ $KBUILD_VERBOSE ]; then
  37                 if [ $KBUILD_VERBOSE -ne 0 ]; then
  38                         echo "Checking prom_init.o symbol '$UNDEF'"
  39                 fi
  40         fi
  41
  42         OK=0
  43         for WHITE in $WHITELIST
  44         do
  45                 if [ "$UNDEF" = "$WHITE" ]; then
  46                         OK=1
  47                         break
  48                 fi
  49         done
  50
  51         # ignore register save/restore funcitons
  52         if [ "${UNDEF:0:9}" = "_restgpr_" ]; then
  53                 OK=1
  54         fi
  55         if [ "${UNDEF:0:11}" = "_rest32gpr_" ]; then
  56                 OK=1
  57         fi
  58         if [ "${UNDEF:0:9}" = "_savegpr_" ]; then
  59                 OK=1
  60         fi
  61         if [ "${UNDEF:0:11}" = "_save32gpr_" ]; then
  62                 OK=1
  63         fi
  64
  65         if [ $OK -eq 0 ]; then
  66                 ERROR=1
  67                 echo "Error: External symbol '$UNDEF' referenced" \
  68                      "from prom_init.c" >&2
  69         fi
  70 done
  71
  72 exit $ERROR