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 opal_query_takeover opal_do_takeover opal_enter_rtas opal_secondary_entry
  25 boot_command_line"
  26
  27 NM="$1"
  28 OBJ="$2"
  29
  30 ERROR=0
  31
  32 for UNDEF in $($NM -u $OBJ | awk '{print $2}')
  33 do
  34         # On 64-bit nm gives us the function descriptors, which have
  35         # a leading . on the name, so strip it off here.
  36         UNDEF="${UNDEF#.}"
  37
  38         if [ $KBUILD_VERBOSE ]; then
  39                 if [ $KBUILD_VERBOSE -ne 0 ]; then
  40                         echo "Checking prom_init.o symbol '$UNDEF'"
  41                 fi
  42         fi
  43
  44         OK=0
  45         for WHITE in $WHITELIST
  46         do
  47                 if [ "$UNDEF" = "$WHITE" ]; then
  48                         OK=1
  49                         break
  50                 fi
  51         done
  52
  53         # ignore register save/restore funcitons
  54         if [ "${UNDEF:0:9}" = "_restgpr_" ]; then
  55                 OK=1
  56         fi
  57         if [ "${UNDEF:0:10}" = "_restgpr0_" ]; then
  58                 OK=1
  59         fi
  60         if [ "${UNDEF:0:11}" = "_rest32gpr_" ]; then
  61                 OK=1
  62         fi
  63         if [ "${UNDEF:0:9}" = "_savegpr_" ]; then
  64                 OK=1
  65         fi
  66         if [ "${UNDEF:0:10}" = "_savegpr0_" ]; then
  67                 OK=1
  68         fi
  69         if [ "${UNDEF:0:11}" = "_save32gpr_" ]; then
  70                 OK=1
  71         fi
  72
  73         if [ $OK -eq 0 ]; then
  74                 ERROR=1
  75                 echo "Error: External symbol '$UNDEF' referenced" \
  76                      "from prom_init.c" >&2
  77         fi
  78 done
  79
  80 exit $ERROR