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70b61e3621
When building with the Gold linker, the .bss and .brk areas of vmlinux
are shown as consecutive instead of having the same file offset. Allow
for either state, as long as things add up correctly.
Fixes: e6023367d7 ("x86, kaslr: Prevent .bss from overlaping initrd")
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Junjie Mao <eternal.n08@gmail.com>
Link: http://lkml.kernel.org/r/20141118001604.GA25045@www.outflux.net
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
39 lines
1 KiB
Perl
39 lines
1 KiB
Perl
#!/usr/bin/perl
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#
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# Calculate the amount of space needed to run the kernel, including room for
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# the .bss and .brk sections.
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#
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# Usage:
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# objdump -h a.out | perl calc_run_size.pl
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use strict;
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my $mem_size = 0;
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my $file_offset = 0;
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my $sections=" *[0-9]+ \.(?:bss|brk) +";
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while (<>) {
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if (/^$sections([0-9a-f]+) +(?:[0-9a-f]+ +){2}([0-9a-f]+)/) {
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my $size = hex($1);
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my $offset = hex($2);
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$mem_size += $size;
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if ($file_offset == 0) {
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$file_offset = $offset;
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} elsif ($file_offset != $offset) {
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# BFD linker shows the same file offset in ELF.
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# Gold linker shows them as consecutive.
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next if ($file_offset + $mem_size == $offset + $size);
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printf STDERR "file_offset: 0x%lx\n", $file_offset;
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printf STDERR "mem_size: 0x%lx\n", $mem_size;
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printf STDERR "offset: 0x%lx\n", $offset;
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printf STDERR "size: 0x%lx\n", $size;
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die ".bss and .brk are non-contiguous\n";
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}
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}
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}
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if ($file_offset == 0) {
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die "Never found .bss or .brk file offset\n";
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}
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printf("%d\n", $mem_size + $file_offset);
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