mirror of
https://github.com/torvalds/linux.git
synced 2024-11-05 11:32:04 +00:00
144ef909c0
When using CONFIG_RELOCATABLE, we build the kernel as a position independent executable. The kernel then uses a little bit of relocation code to relocate itself. That code only deals with R_PPC64_RELATIVE relocations though. If for some reason you use assembly constructs such as LOAD_REG_IMMEDIATE() to load the address of a symbol, you'll generate different kinds of relocations that won't be processed properly and bad things will happen. (We have 2 such bugs today). The perl script tries to filter out "known" bad ones. It's possible that we are missing some in the case of a weak function that nobody implements, we'll see if we get false positive and fix it. Signed-off-by: Tony Breeds <tony@bakeyournoodle.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
57 lines
1.3 KiB
Perl
Executable File
57 lines
1.3 KiB
Perl
Executable File
#!/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 relcoations of a vmlinux for "suspicious"
|
|
# relocations.
|
|
|
|
use strict;
|
|
use warnings;
|
|
|
|
if ($#ARGV != 1) {
|
|
die "$0 [path to objdump] [path to vmlinux]\n";
|
|
}
|
|
|
|
# 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 relcoation lines.
|
|
next if (!/\s+R_/);
|
|
|
|
# These relocations are okay
|
|
next if (/R_PPC64_RELATIVE/ or /R_PPC64_NONE/ or
|
|
/R_PPC64_ADDR64\s+mach_/);
|
|
|
|
# If we see this type of relcoation 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\n";
|
|
print $bad_relocs;
|
|
}
|
|
|
|
if ($old_binutils) {
|
|
print "WARNING: You need at binutils >= 2.19 to build a ".
|
|
"CONFIG_RELCOATABLE kernel\n";
|
|
}
|