From: Michael Brown Date: Fri, 15 Aug 2008 03:10:35 +0000 (+0100) Subject: [util] Allow Option::ROM to understand and modify initialisation entry point X-Git-Tag: v0.9.4~53 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=23bca8f9d86da54859996acb07a0bc07daee4955;p=thirdparty%2Fipxe.git [util] Allow Option::ROM to understand and modify initialisation entry point Add support for manipulating the jump instruction that forms the option ROM initialisation entry point, so that mergerom.pl can treat it just like other entry points. Add support for merging the initialisation entry point (and IBM BOFM table) to mergerom.pl; this is another slightly icky but unfortunately necessary GPL vs. NDA workaround. When mergerom.pl replaces an entry point in the original ROM, it now fills in the corresponding entry point in the merged ROM with the original value; this allows (for example) a merged initialisation entry point to do some processing and then jump back to the original entry point. --- diff --git a/src/util/Option/ROM.pm b/src/util/Option/ROM.pm index f5c33f8a2..7a1bb8838 100644 --- a/src/util/Option/ROM.pm +++ b/src/util/Option/ROM.pm @@ -73,7 +73,10 @@ sub FETCH { my $raw = substr ( ${$self->{data}}, ( $self->{offset} + $self->{fields}->{$key}->{offset} ), $self->{fields}->{$key}->{length} ); - return unpack ( $self->{fields}->{$key}->{pack}, $raw ); + my $unpack = ( ref $self->{fields}->{$key}->{unpack} ? + $self->{fields}->{$key}->{unpack} : + sub { unpack ( $self->{fields}->{$key}->{pack}, shift ); } ); + return &$unpack ( $raw ); } sub STORE { @@ -82,7 +85,10 @@ sub STORE { my $value = shift; croak "Nonexistent field \"$key\"" unless $self->EXISTS ( $key ); - my $raw = pack ( $self->{fields}->{$key}->{pack}, $value ); + my $pack = ( ref $self->{fields}->{$key}->{pack} ? + $self->{fields}->{$key}->{pack} : + sub { pack ( $self->{fields}->{$key}->{pack}, shift ); } ); + my $raw = &$pack ( $value ); substr ( ${$self->{data}}, ( $self->{offset} + $self->{fields}->{$key}->{offset} ), $self->{fields}->{$key}->{length} ) = $raw; @@ -168,6 +174,36 @@ use constant PNP_SIGNATURE => '$PnP'; our @EXPORT_OK = qw ( ROM_SIGNATURE PCI_SIGNATURE PNP_SIGNATURE ); our %EXPORT_TAGS = ( all => [ @EXPORT_OK ] ); +use constant JMP_SHORT => 0xeb; +use constant JMP_NEAR => 0xe9; + +sub pack_init { + my $dest = shift; + + # Always create a near jump; it's simpler + if ( $dest ) { + return pack ( "CS", JMP_NEAR, ( $dest - 6 ) ); + } else { + return pack ( "CS", 0, 0 ); + } +} + +sub unpack_init { + my $instr = shift; + + # Accept both short and near jumps + ( my $jump, my $offset ) = unpack ( "CS", $instr ); + if ( $jump == JMP_SHORT ) { + return ( $offset + 5 ); + } elsif ( $jump == JMP_NEAR ) { + return ( $offset + 6 ); + } elsif ( $jump == 0 ) { + return 0; + } else { + croak "Unrecognised jump instruction in init vector\n"; + } +} + =pod =item C<< new () >> @@ -187,7 +223,11 @@ sub new { fields => { signature => { offset => 0x00, length => 0x02, pack => "S" }, length => { offset => 0x02, length => 0x01, pack => "C" }, + # "init" is part of a jump instruction + init => { offset => 0x03, length => 0x03, + pack => \&pack_init, unpack => \&unpack_init }, checksum => { offset => 0x06, length => 0x01, pack => "C" }, + bofm_header => { offset => 0x14, length => 0x02, pack => "S" }, undi_header => { offset => 0x16, length => 0x02, pack => "S" }, pci_header => { offset => 0x18, length => 0x02, pack => "S" }, pnp_header => { offset => 0x1a, length => 0x02, pack => "S" }, diff --git a/src/util/disrom.pl b/src/util/disrom.pl index c472037af..80ac4af8f 100755 --- a/src/util/disrom.pl +++ b/src/util/disrom.pl @@ -38,6 +38,7 @@ die "ROM image truncated (is $filelength, should be $romlength)\n" printf "ROM header:\n\n"; printf " Length:\t0x%02x (%d)\n", $rom->{length}, ( $rom->{length} * 512 ); printf " Checksum:\t0x%02x (0x%02x)\n", $rom->{checksum}, $rom->checksum; +printf " Init:\t\t0x%04x\n", $rom->{init}; printf " UNDI header:\t0x%04x\n", $rom->{undi_header}; printf " PCI header:\t0x%04x\n", $rom->{pci_header}; printf " PnP header:\t0x%04x\n", $rom->{pnp_header}; diff --git a/src/util/mergerom.pl b/src/util/mergerom.pl index ce1befb7f..f9c52502d 100755 --- a/src/util/mergerom.pl +++ b/src/util/mergerom.pl @@ -23,6 +23,18 @@ use FindBin; use lib "$FindBin::Bin"; use Option::ROM qw ( :all ); +sub merge_entry_points { + my $baserom_entry = \shift; + my $rom_entry = \shift; + my $offset = shift; + + if ( $$rom_entry ) { + my $old_entry = $$baserom_entry; + $$baserom_entry = ( $offset + $$rom_entry ); + $$rom_entry = $old_entry; + } +} + my @romfiles = @ARGV; my @roms = map { my $rom = new Option::ROM; $rom->load($_); $rom } @romfiles; @@ -34,6 +46,12 @@ foreach my $rom ( @roms ) { # Update base length $baserom->{length} += $rom->{length}; + # Merge initialisation entry point + merge_entry_points ( $baserom->{init}, $rom->{init}, $offset ); + + # Merge BOFM header + merge_entry_points ( $baserom->{bofm_header}, $rom->{bofm_header}, $offset ); + # Update PCI header, if present in both my $baserom_pci = $baserom->pci_header; my $rom_pci = $rom->pci_header; @@ -52,8 +70,8 @@ foreach my $rom ( @roms ) { # Merge CLP entry point if ( exists ( $baserom_pci->{clp_entry} ) && exists ( $rom_pci->{clp_entry} ) ) { - $baserom_pci->{clp_entry} = ( $offset + $rom_pci->{clp_entry} ) - if $rom_pci->{clp_entry}; + merge_entry_points ( $baserom_pci->{clp_entry}, $rom_pci->{clp_entry}, + $offset ); } } @@ -61,9 +79,9 @@ foreach my $rom ( @roms ) { my $baserom_pnp = $baserom->pnp_header; my $rom_pnp = $rom->pnp_header; if ( $baserom_pnp && $rom_pnp ) { - $baserom_pnp->{bcv} = ( $offset + $rom_pnp->{bcv} ) if $rom_pnp->{bcv}; - $baserom_pnp->{bdv} = ( $offset + $rom_pnp->{bdv} ) if $rom_pnp->{bdv}; - $baserom_pnp->{bev} = ( $offset + $rom_pnp->{bev} ) if $rom_pnp->{bev}; + merge_entry_points ( $baserom_pnp->{bcv}, $rom_pnp->{bcv}, $offset ); + merge_entry_points ( $baserom_pnp->{bdv}, $rom_pnp->{bdv}, $offset ); + merge_entry_points ( $baserom_pnp->{bev}, $rom_pnp->{bev}, $offset ); } # Fix checksum for this ROM segment