From: Marty Connor <mdc@etherboot.org>
Date: Thu, 18 Dec 2008 04:28:27 +0000 (-0500)
Subject: [pcbios] Add additional sanity check for bogus e820 map
X-Git-Tag: v0.9.7~92
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8674bc05a054fe8c0ef5ed4e6696d0f1168af74c;p=thirdparty%2Fipxe.git

[pcbios] Add additional sanity check for bogus e820 map

At POST time some BIOSes return invalid e820 maps even though
they indicate that the data is valid.  We add a check that the first
region returned by e820 is RAM type and declare the map to be invalid
if it is not.

This extends the sanity checks from 8b20e5d ("[pcbios] Sanity-check
the INT15,e820 and INT15,e801 memory maps").
---

diff --git a/src/arch/i386/firmware/pcbios/memmap.c b/src/arch/i386/firmware/pcbios/memmap.c
index 3546dc6fe..ff387d93f 100644
--- a/src/arch/i386/firmware/pcbios/memmap.c
+++ b/src/arch/i386/firmware/pcbios/memmap.c
@@ -201,6 +201,13 @@ static int meme820 ( struct memory_map *memmap ) {
 			break;
 		}
 
+		/* If first region is not RAM, assume map is invalid */
+		if ( ( memmap->count == 0 ) &&
+		     ( e820buf.type != E820_TYPE_RAM ) ) {
+		       DBG ( "INT 15,e820 failed, first entry not RAM\n" );
+		       return -EINVAL;
+		}
+
 		DBG ( "INT 15,e820 region [%llx,%llx) type %d",
 		      e820buf.start, ( e820buf.start + e820buf.len ),
 		      ( int ) e820buf.type );