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x86, setup: "glove box" BIOS interrupts in the MCA code

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Impact: BIOS proofing

"Glove box" off BIOS interrupts in the MCA code.

LKML-Reference: <49DE7F79.4030106@zytor.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
This commit is contained in:
H. Peter Anvin 2009-04-01 18:19:00 -07:00 committed by H. Peter Anvin
parent 3435d3476c
commit 0a706db320
1 changed files with 10 additions and 13 deletions
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23
arch/x86/boot/mca.c
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@ -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.
@ -16,26 +17,22 @@
int query_mca(void)
{
u8 err;
u16 es, bx, len;
struct biosregs ireg, oreg;
u16 len;
asm("pushw %%es ; "
"int $0x15 ; "
"setc %0 ; "
"movw %%es, %1 ; "
"popw %%es"
: "=acd" (err), "=acdSD" (es), "=b" (bx)
: "a" (0xc000));
initregs(&ireg);
ireg.ah = 0xc0;
intcall(0x15, &ireg, &oreg);
if (err)
if (oreg.eflags & X86_EFLAGS_CF)
return -1; /* No MCA present */
set_fs(es);
len = rdfs16(bx);
set_fs(oreg.es);
len = rdfs16(oreg.bx);
if (len > sizeof(boot_params.sys_desc_table))
len = sizeof(boot_params.sys_desc_table);
copy_from_fs(&boot_params.sys_desc_table, bx, len);
copy_from_fs(&boot_params.sys_desc_table, oreg.bx, len);
return 0;
}