arch/powerpc/tools/relocs_check.sh

   1 #!/bin/sh
   2 # SPDX-License-Identifier: GPL-2.0-or-later
   3
   4 # Copyright © 2015 IBM Corporation
   5
   6
   7 # This script checks the relocations of a vmlinux for "suspicious"
   8 # relocations.
   9
  10 # based on relocs_check.pl
  11 # Copyright © 2009 IBM Corporation
  12
  13 if [ $# -lt 3 ]; then
  14         echo "$0 [path to objdump] [path to nm] [path to vmlinux]" 1>&2
  15         exit 1
  16 fi
  17
  18 # Have Kbuild supply the path to objdump and nm so we handle cross compilation.
  19 objdump="$1"
  20 nm="$2"
  21 vmlinux="$3"
  22
  23 # Remove from the bad relocations those that match an undefined weak symbol
  24 # which will result in an absolute relocation to 0.
  25 # Weak unresolved symbols are of that form in nm output:
  26 # "                  w _binary__btf_vmlinux_bin_end"
  27 undef_weak_symbols=$($nm "$vmlinux" | awk '$1 ~ /w/ { print $2 }')
  28
  29 bad_relocs=$(
  30 $objdump -R "$vmlinux" |
  31         # Only look at relocation lines.
  32         grep -E '\<R_' |
  33         # These relocations are okay
  34         # On PPC64:
  35         #       R_PPC64_RELATIVE, R_PPC64_NONE
  36         # On PPC:
  37         #       R_PPC_RELATIVE, R_PPC_ADDR16_HI,
  38         #       R_PPC_ADDR16_HA,R_PPC_ADDR16_LO,
  39         #       R_PPC_NONE
  40         grep -F -w -v 'R_PPC64_RELATIVE
  41 R_PPC64_NONE
  42 R_PPC_ADDR16_LO
  43 R_PPC_ADDR16_HI
  44 R_PPC_ADDR16_HA
  45 R_PPC_RELATIVE
  46 R_PPC_NONE' |
  47         ([ "$undef_weak_symbols" ] && grep -F -w -v "$undef_weak_symbols" || cat)
  48 )
  49
  50 if [ -z "$bad_relocs" ]; then
  51         exit 0
  52 fi
  53
  54 num_bad=$(echo "$bad_relocs" | wc -l)
  55 echo "WARNING: $num_bad bad relocations"
  56 echo "$bad_relocs"
  57
  58 # If we see this type of relocation it's an idication that
  59 # we /may/ be using an old version of binutils.
  60 if echo "$bad_relocs" | grep -q -F -w R_PPC64_UADDR64; then
  61         echo "WARNING: You need at least binutils >= 2.19 to build a CONFIG_RELOCATABLE kernel"
  62 fi