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: H. Peter Anvin <hpa@linux.intel.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
diff --git a/arch/x86/boot/mca.c b/arch/x86/boot/mca.c
index 911eaae..a95a531 100644
--- a/arch/x86/boot/mca.c
+++ b/arch/x86/boot/mca.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.
@@ -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;
}