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 _stext
  24 __prom_init_toc_start __prom_init_toc_end btext_setup_display TOC."
  25
  26 NM="$1"
  27 OBJ="$2"
  28
  29 ERROR=0
  30
  31 for UNDEF in $($NM -u $OBJ | awk '{print $2}')
  32 do
  33         # On 64-bit nm gives us the function descriptors, which have
  34         # a leading . on the name, so strip it off here.
  35         UNDEF="${UNDEF#.}"
  36
  37         if [ $KBUILD_VERBOSE ]; then
  38                 if [ $KBUILD_VERBOSE -ne 0 ]; then
  39                         echo "Checking prom_init.o symbol '$UNDEF'"
  40                 fi
  41         fi
  42
  43         OK=0
  44         for WHITE in $WHITELIST
  45         do
  46                 if [ "$UNDEF" = "$WHITE" ]; then
  47                         OK=1
  48                         break
  49                 fi
  50         done
  51
  52         # ignore register save/restore funcitons
  53         case $UNDEF in
  54         _restgpr_*|_restgpr0_*|_rest32gpr_*)
  55                 OK=1
  56                 ;;
  57         _savegpr_*|_savegpr0_*|_save32gpr_*)
  58                 OK=1
  59                 ;;
  60         esac
  61
  62         if [ $OK -eq 0 ]; then
  63                 ERROR=1
  64                 echo "Error: External symbol '$UNDEF' referenced" \
  65                      "from prom_init.c" >&2
  66         fi
  67 done
  68
  69 exit $ERROR