#!/usr/bin/perl
  
  # Copyright © 2009 IBM Corporation
  
  # This program is free software; you can redistribute it and/or
  # modify it under the terms of the GNU General Public License
  # as published by the Free Software Foundation; either version
  # 2 of the License, or (at your option) any later version.
  
  # This script checks the relocations of a vmlinux for "suspicious"
  # relocations.
  
  use strict;
  use warnings;
  
  if ($#ARGV != 1) {
  	die "$0 [path to objdump] [path to vmlinux]
  ";
  }
  
  # Have Kbuild supply the path to objdump so we handle cross compilation.
  my $objdump = shift;
  my $vmlinux = shift;
  my $bad_relocs_count = 0;
  my $bad_relocs = "";
  my $old_binutils = 0;
  
  open(FD, "$objdump -R $vmlinux|") or die;
  while (<FD>) {
  	study $_;
  
  	# Only look at relocation lines.
  	next if (!/\s+R_/);
  
  	# These relocations are okay
  	# On PPC64:
  	# 	R_PPC64_RELATIVE, R_PPC64_NONE, R_PPC64_ADDR64
  	# On PPC:
  	# 	R_PPC_RELATIVE, R_PPC_ADDR16_HI, 
  	# 	R_PPC_ADDR16_HA,R_PPC_ADDR16_LO,
  	# 	R_PPC_NONE
  
  	next if (/\bR_PPC64_RELATIVE\b/ or /\bR_PPC64_NONE\b/ or
  	         /\bR_PPC64_ADDR64\s+mach_/);
  	next if (/\bR_PPC_ADDR16_LO\b/ or /\bR_PPC_ADDR16_HI\b/ or
  		 /\bR_PPC_ADDR16_HA\b/ or /\bR_PPC_RELATIVE\b/ or
  		 /\bR_PPC_NONE\b/);
  
  	# If we see this type of relocation it's an idication that
  	# we /may/ be using an old version of binutils.
  	if (/R_PPC64_UADDR64/) {
  		$old_binutils++;
  	}
  
  	$bad_relocs_count++;
  	$bad_relocs .= $_;
  }
  
  if ($bad_relocs_count) {
  	print "WARNING: $bad_relocs_count bad relocations
  ";
  	print $bad_relocs;
  }
  
  if ($old_binutils) {
  	print "WARNING: You need at least binutils >= 2.19 to build a ".
  	      "CONFIG_RELOCATABLE kernel
  ";
  }