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Commit 0a706db3 authored by H. Peter Anvin's avatar H. Peter Anvin Committed by H. Peter Anvin
Browse files

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



Impact: BIOS proofing

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

LKML-Reference: <49DE7F79.4030106@zytor.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@linux.intel.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
parent 3435d347

arch/x86/boot/mca.c

+12 −15
Original line number Original line Diff line number Diff line
@@ -2,6 +2,7 @@ 
 *

 *

 *   Copyright (C) 1991, 1992 Linus Torvalds

 *   Copyright (C) 1991, 1992 Linus Torvalds

 *   Copyright 2007 rPath, Inc. - All Rights Reserved

 *   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

 *   This file is part of the Linux kernel, and is made available under

 *   the terms of the GNU General Public License version 2.

 *   the terms of the GNU General Public License version 2.
@@ -16,26 +17,22 @@ 




int query_mca(void)

int query_mca(void)

{

{

	u8 err;

	struct biosregs ireg, oreg;

	u16 es, bx, len;

	u16 len;





	asm("pushw %%es ; "

	initregs(&ireg);

	    "int $0x15 ; "

	ireg.ah = 0xc0;

	    "setc %0 ; "

	intcall(0x15, &ireg, &oreg);

	    "movw %%es, %1 ; "



	    "popw %%es"

	if (oreg.eflags & X86_EFLAGS_CF)

	    : "=acd" (err), "=acdSD" (es), "=b" (bx)

	    : "a" (0xc000));



	if (err)

		return -1;	/* No MCA present */

		return -1;	/* No MCA present */





	set_fs(es);

	set_fs(oreg.es);

	len = rdfs16(bx);

	len = rdfs16(oreg.bx);





	if (len > sizeof(boot_params.sys_desc_table))

	if (len > sizeof(boot_params.sys_desc_table))

		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;

	return 0;

}
 
}