X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=arch%2Fx86%2Fboot%2Fedd.c;h=1aae8f3e5ca1912b6eb60ad75e3c120af1110bed;hb=6925bac120097b823fc990c143b9789c21cc60b5;hp=03399d64013b21459f63942c06bc6c33b803f425;hpb=a815752ac0ffdb910e92958d41d28f4fb28e5296;p=linux-2.6-omap-h63xx.git

diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c
index 03399d64013..1aae8f3e5ca 100644
--- a/arch/x86/boot/edd.c
+++ b/arch/x86/boot/edd.c
@@ -41,6 +41,7 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
 	char *mbrbuf_ptr, *mbrbuf_end;
 	u32 buf_base, mbr_base;
 	extern char _end[];
+	u16 mbr_magic;
 
 	sector_size = ei->params.bytes_per_sector;
 	if (!sector_size)
@@ -58,11 +59,15 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
 	if (mbrbuf_end > (char *)(size_t)boot_params.hdr.heap_end_ptr)
 		return -1;
 
+	memset(mbrbuf_ptr, 0, sector_size);
 	if (read_mbr(devno, mbrbuf_ptr))
 		return -1;
 
 	*mbrsig = *(u32 *)&mbrbuf_ptr[EDD_MBR_SIG_OFFSET];
-	return 0;
+	mbr_magic = *(u16 *)&mbrbuf_ptr[510];
+
+	/* check for valid MBR magic */
+	return mbr_magic == 0xAA55 ? 0 : -1;
 }
 
 static int get_edd_info(u8 devno, struct edd_info *ei)
@@ -167,9 +172,8 @@ void query_edd(void)
 		 * Scan the BIOS-supported hard disks and query EDD
 		 * information...
 		 */
-		get_edd_info(devno, &ei);
-
-		if (boot_params.eddbuf_entries < EDDMAXNR) {
+		if (!get_edd_info(devno, &ei)
+		    && boot_params.eddbuf_entries < EDDMAXNR) {
 			memcpy(edp, &ei, sizeof ei);
 			edp++;
 			boot_params.eddbuf_entries++;