diff options
Diffstat (limited to 'arch/x86/boot/edd.c')
| -rw-r--r-- | arch/x86/boot/edd.c | 12 |
1 files changed, 8 insertions, 4 deletions
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++; |