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 (file)
--- 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;
-
-       asm("pushw %%es ; "
-           "int $0x15 ; "
-           "setc %0 ; "
-           "movw %%es, %1 ; "
-           "popw %%es"
-           : "=acd" (err), "=acdSD" (es), "=b" (bx)
-           : "a" (0xc000));
-
-       if (err)
+       struct biosregs ireg, oreg;
+       u16 len;
+
+       initregs(&ireg);
+       ireg.ah = 0xc0;
+       intcall(0x15, &ireg, &oreg);
+
+       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;
 }