[romprefix] Report a pessimistic runtime size estimate

PCI3.0 allows us to report a "runtime size" which can be smaller than
the actual ROM size.  On systems that support PMM our runtime size
will be small (~2.5kB), which helps to conserve the limited option ROM
space.  However, there is no guarantee that the PMM allocation will
succeed, and so we need to report the worst-case runtime size in the
PCI header.

Move the "shrunk ROM size" field from the PCI header to a new "iPXE
ROM header", allowing it to be accessed by ROM-manipulation utilities
such as disrom.pl.

Reported-by: Anton D. Kachalov <mouse@yandex-team.ru>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/src/util/disrom.pl b/src/util/disrom.pl
index c133c26a..87138686 100755
--- a/src/util/disrom.pl
+++ b/src/util/disrom.pl
@@ -85,4 +85,15 @@ do {
     printf "\n";
   }
 
+  my $ipxe = $rom->ipxe_header();
+  if ( $ipxe ) {
+    printf "iPXE header:\n\n";
+    printf "  %-16s 0x%02x (%s0x%02x)\n", "Checksum:", $ipxe->{checksum},
+	   ( ( $ipxe->checksum == 0 ) ? "" : "INCORRECT: " ), $ipxe->checksum;
+    printf "  %-16s 0x%02x (%d)\n", "Shrunk length:",
+	   $ipxe->{shrunk_length}, ( $ipxe->{shrunk_length} * 512 );
+    printf "  %-16s 0x%08x\n", "Build ID:", $ipxe->{build_id};
+    printf "\n";
+  }
+
 } while ( $rom = $rom->next_image );