blob: 9b68bd1aef19d35c2ae5c75a790a2fd7dc93ba33 [file] [log] [blame]
H. Peter Anvin3b53d30452007-07-11 12:18:49 -07001/* -*- linux-c -*- ------------------------------------------------------- *
2 *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright 2007 rPath, Inc. - All Rights Reserved
5 *
6 * This file is part of the Linux kernel, and is made available under
7 * the terms of the GNU General Public License version 2.
8 *
9 * ----------------------------------------------------------------------- */
10
11/*
12 * arch/i386/boot/mca.c
13 *
14 * Get the MCA system description table
15 */
16
17#include "boot.h"
18
19int query_mca(void)
20{
21 u8 err;
22 u16 es, bx, len;
23
24 asm("pushw %%es ; "
25 "int $0x15 ; "
26 "setc %0 ; "
27 "movw %%es, %1 ; "
28 "popw %%es"
29 : "=acdSDm" (err), "=acdSDm" (es), "=b" (bx)
30 : "a" (0xc000));
31
32 if (err)
33 return -1; /* No MCA present */
34
35 set_fs(es);
36 len = rdfs16(bx);
37
38 if (len > sizeof(boot_params.sys_desc_table))
39 len = sizeof(boot_params.sys_desc_table);
40
41 copy_from_fs(&boot_params.sys_desc_table, bx, len);
42 return 0;
43}