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author | fishsoupisgood <github@madingley.org> | 2019-04-29 01:17:54 +0100 |
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committer | fishsoupisgood <github@madingley.org> | 2019-05-27 03:43:43 +0100 |
commit | 3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch) | |
tree | 65ca85f13617aee1dce474596800950f266a456c /roms/ipxe/src/util/swapdevids.pl | |
download | qemu-3f2546b2ef55b661fd8dd69682b38992225e86f6.tar.gz qemu-3f2546b2ef55b661fd8dd69682b38992225e86f6.tar.bz2 qemu-3f2546b2ef55b661fd8dd69682b38992225e86f6.zip |
Diffstat (limited to 'roms/ipxe/src/util/swapdevids.pl')
-rwxr-xr-x | roms/ipxe/src/util/swapdevids.pl | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/roms/ipxe/src/util/swapdevids.pl b/roms/ipxe/src/util/swapdevids.pl new file mode 100755 index 00000000..c6255ae7 --- /dev/null +++ b/roms/ipxe/src/util/swapdevids.pl @@ -0,0 +1,49 @@ +#!/usr/bin/perl -w +# +# Program to reverse the device identifier IDs in the PCIR and PnP +# structures in a ROM for old non-compliant BIOSes +# +# GPL, Ken Yap 2001 +# + +use bytes; + +use IO::Seekable; + +sub swaplocs ($$$) +{ + my ($dataref, $loc1, $loc2) = @_; + my ($t); + + $t = substr($$dataref, $loc1, 1); + substr($$dataref, $loc1, 1) = substr($$dataref, $loc2, 1); + substr($$dataref, $loc2, 1) = $t; +} + +sub printdevids ($$) +{ + my ($dataref, $loc) = @_; + + return (sprintf "%02x %02x %02x", unpack('C3', substr($$dataref, $loc, 3))); +} + +$#ARGV >= 0 or die "Usage: $0 romimage\n"; +$file = $ARGV[0]; +open(F, "+<$file") or die "$file: $!\n"; +binmode(F); +# Handle up to 64kB ROM images +$len = read(F, $data, 64*1024); +defined($len) or die "$file: $!\n"; +substr($data, 0, 2) eq "\x55\xAA" or die "$file: Not a boot ROM image\n"; +($pci, $pnp) = unpack('v2', substr($data, 0x18, 4)); +($pci < $len and $pnp < $len) or die "$file: Not a PCI PnP ROM image\n"; +(substr($data, $pci, 4) eq 'PCIR' and substr($data, $pnp, 4) eq '$PnP') + or die "$file: No PCI and PNP structures, not a PCI PNP ROM image\n"; +&swaplocs(\$data, $pci+13, $pci+15); +&swaplocs(\$data, $pnp+18, $pnp+20); +seek(F, 0, SEEK_SET) or die "$file: Cannot seek to beginning\n"; +print F $data; +close(F); +print "PCI devids now: ", &printdevids(\$data, $pci+13), "\n"; +print "PnP devids now: ", &printdevids(\$data, $pnp+18), "\n"; +exit(0); |