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Date: Thu, 9 Apr 2009 23:13:24 GMT
From: "H. Peter Anvin" <hpa@...ux.intel.com>
To: linux-tip-commits@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, hpa@...or.com, mingo@...hat.com,
tglx@...utronix.de, hpa@...ux.intel.com
Subject: [tip:x86/setup] x86, setup: "glove box" BIOS interrupts in the EDD code
Commit-ID: 3435d3476c5ed955d56a6216ed2d156847b3a575
Gitweb: http://git.kernel.org/tip/3435d3476c5ed955d56a6216ed2d156847b3a575
Author: H. Peter Anvin <hpa@...ux.intel.com>
AuthorDate: Wed, 1 Apr 2009 18:17:17 -0700
Committer: H. Peter Anvin <hpa@...or.com>
CommitDate: Thu, 9 Apr 2009 16:08:11 -0700
x86, setup: "glove box" BIOS interrupts in the EDD code
Impact: BIOS proofing
"Glove box" off BIOS interrupts in the EDD code.
LKML-Reference: <49DE7F79.4030106@...or.com>
Signed-off-by: H. Peter Anvin <hpa@...ux.intel.com>
---
arch/x86/boot/edd.c | 71 ++++++++++++++++++++++----------------------------
1 files changed, 31 insertions(+), 40 deletions(-)
diff --git a/arch/x86/boot/edd.c b/arch/x86/boot/edd.c
index 1aae8f3..c501a5b 100644
--- a/arch/x86/boot/edd.c
+++ b/arch/x86/boot/edd.c
@@ -2,6 +2,7 @@
*
* Copyright (C) 1991, 1992 Linus Torvalds
* Copyright 2007 rPath, Inc. - All Rights Reserved
+ * Copyright 2009 Intel Corporation; author H. Peter Anvin
*
* This file is part of the Linux kernel, and is made available under
* the terms of the GNU General Public License version 2.
@@ -22,17 +23,17 @@
*/
static int read_mbr(u8 devno, void *buf)
{
- u16 ax, bx, cx, dx;
+ struct biosregs ireg, oreg;
- ax = 0x0201; /* Legacy Read, one sector */
- cx = 0x0001; /* Sector 0-0-1 */
- dx = devno;
- bx = (size_t)buf;
- asm volatile("pushfl; stc; int $0x13; setc %%al; popfl"
- : "+a" (ax), "+c" (cx), "+d" (dx), "+b" (bx)
- : : "esi", "edi", "memory");
+ initregs(&ireg);
+ ireg.ax = 0x0201; /* Legacy Read, one sector */
+ ireg.cx = 0x0001; /* Sector 0-0-1 */
+ ireg.dl = devno;
+ ireg.bx = (size_t)buf;
- return -(u8)ax; /* 0 or -1 */
+ intcall(0x13, &ireg, &oreg);
+
+ return -(oreg.eflags & X86_EFLAGS_CF); /* 0 or -1 */
}
static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
@@ -72,56 +73,46 @@ static u32 read_mbr_sig(u8 devno, struct edd_info *ei, u32 *mbrsig)
static int get_edd_info(u8 devno, struct edd_info *ei)
{
- u16 ax, bx, cx, dx, di;
+ struct biosregs ireg, oreg;
memset(ei, 0, sizeof *ei);
/* Check Extensions Present */
- ax = 0x4100;
- bx = EDDMAGIC1;
- dx = devno;
- asm("pushfl; stc; int $0x13; setc %%al; popfl"
- : "+a" (ax), "+b" (bx), "=c" (cx), "+d" (dx)
- : : "esi", "edi");
+ initregs(&ireg);
+ ireg.ah = 0x41;
+ ireg.bx = EDDMAGIC1;
+ ireg.dl = devno;
+ intcall(0x13, &ireg, &oreg);
- if ((u8)ax)
+ if (oreg.eflags & X86_EFLAGS_CF)
return -1; /* No extended information */
- if (bx != EDDMAGIC2)
+ if (oreg.bx != EDDMAGIC2)
return -1;
ei->device = devno;
- ei->version = ax >> 8; /* EDD version number */
- ei->interface_support = cx; /* EDD functionality subsets */
+ ei->version = oreg.ah; /* EDD version number */
+ ei->interface_support = oreg.cx; /* EDD functionality subsets */
/* Extended Get Device Parameters */
ei->params.length = sizeof(ei->params);
- ax = 0x4800;
- dx = devno;
- asm("pushfl; int $0x13; popfl"
- : "+a" (ax), "+d" (dx), "=m" (ei->params)
- : "S" (&ei->params)
- : "ebx", "ecx", "edi");
+ ireg.ah = 0x48;
+ ireg.si = (size_t)&ei->params;
+ intcall(0x13, &ireg, &oreg);
/* Get legacy CHS parameters */
/* Ralf Brown recommends setting ES:DI to 0:0 */
- ax = 0x0800;
- dx = devno;
- di = 0;
- asm("pushw %%es; "
- "movw %%di,%%es; "
- "pushfl; stc; int $0x13; setc %%al; popfl; "
- "popw %%es"
- : "+a" (ax), "=b" (bx), "=c" (cx), "+d" (dx), "+D" (di)
- : : "esi");
-
- if ((u8)ax == 0) {
- ei->legacy_max_cylinder = (cx >> 8) + ((cx & 0xc0) << 2);
- ei->legacy_max_head = dx >> 8;
- ei->legacy_sectors_per_track = cx & 0x3f;
+ ireg.ah = 0x08;
+ ireg.es = 0;
+ intcall(0x13, &ireg, &oreg);
+
+ if (!(oreg.eflags & X86_EFLAGS_CF)) {
+ ei->legacy_max_cylinder = oreg.ch + ((oreg.cl & 0xc0) << 2);
+ ei->legacy_max_head = oreg.dh;
+ ei->legacy_sectors_per_track = oreg.cl & 0x3f;
}
return 0;
--
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