diff options
author | Andrey Borzenkov <arvidjaar@newmail.ru> | 2008-10-03 13:08:49 -0400 |
---|---|---|
committer | H. Peter Anvin <hpa@zytor.com> | 2008-10-03 13:15:29 -0400 |
commit | 6cdcdb99cf7c2e1835fc5b471864d21161c3e679 (patch) | |
tree | e3dab8fad3748c93fc0870964cbfa8ec8f2e84b6 /arch/x86 | |
parent | 464f04c9e9b3b1c4f5ffb89c51d8ba2a2034c846 (diff) |
x86 setup: fix ghost entries under /sys/firmware/edd take 3
Some BIOSes do not indicate error when trying to read from non-
existing device. Zero buffer before reading and check that we
possibly have valid MBR by looking for MBR magic.
This was fixed in different way for edd.S in
http://marc.info/?l=linux-kernel&m=114087765422490&w=2, but lost
again when edd.S was rewritten in C.
Signed-off-by: Andrey Borzenkov < arvidjaar@mail.ru>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86')
-rw-r--r-- | arch/x86/boot/edd.c | 7 |
1 files changed, 6 insertions, 1 deletions
diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c index bf4ae6ff518e..067e28cd3c5f 100644 --- a/arch/x86/boot/edd.c +++ b/arch/x86/boot/edd.c | |||
@@ -43,6 +43,7 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig) | |||
43 | char *mbrbuf_ptr, *mbrbuf_end; | 43 | char *mbrbuf_ptr, *mbrbuf_end; |
44 | u32 buf_base, mbr_base; | 44 | u32 buf_base, mbr_base; |
45 | extern char _end[]; | 45 | extern char _end[]; |
46 | u16 mbr_magic; | ||
46 | 47 | ||
47 | sector_size = ei->params.bytes_per_sector; | 48 | sector_size = ei->params.bytes_per_sector; |
48 | if (!sector_size) | 49 | if (!sector_size) |
@@ -60,11 +61,15 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig) | |||
60 | if (mbrbuf_end > (char *)(size_t)boot_params.hdr.heap_end_ptr) | 61 | if (mbrbuf_end > (char *)(size_t)boot_params.hdr.heap_end_ptr) |
61 | return -1; | 62 | return -1; |
62 | 63 | ||
64 | memset(mbrbuf_ptr, 0, sector_size); | ||
63 | if (read_mbr(devno, mbrbuf_ptr)) | 65 | if (read_mbr(devno, mbrbuf_ptr)) |
64 | return -1; | 66 | return -1; |
65 | 67 | ||
66 | *mbrsig = *(u32 *)&mbrbuf_ptr[EDD_MBR_SIG_OFFSET]; | 68 | *mbrsig = *(u32 *)&mbrbuf_ptr[EDD_MBR_SIG_OFFSET]; |
67 | return 0; | 69 | mbr_magic = *(u16 *)&mbrbuf_ptr[510]; |
70 | |||
71 | /* check for valid MBR magic */ | ||
72 | return mbr_magic == 0xAA55 ? 0 : -1; | ||
68 | } | 73 | } |
69 | 74 | ||
70 | static int get_edd_info(u8 devno, struct edd_info *ei) | 75 | static int get_edd_info(u8 devno, struct edd_info *ei) |