1 /* -*- linux-c -*- ------------------------------------------------------- *
2  *
3  *   Copyright (C) 1991, 1992 Linus Torvalds
4  *   Copyright 2007 rPath, Inc. - All Rights Reserved
5  *   Copyright 2009 Intel Corporation; author H. Peter Anvin
6  *
7  *   This file is part of the Linux kernel, and is made available under
8  *   the terms of the GNU General Public License version 2.
9  *
10  * ----------------------------------------------------------------------- */
11 
12 /*
13  * Get the MCA system description table
14  */
15 
16 #include "boot.h"
17 
query_mca(void)18 int query_mca(void)
19 {
20 	struct biosregs ireg, oreg;
21 	u16 len;
22 
23 	initregs(&ireg);
24 	ireg.ah = 0xc0;
25 	intcall(0x15, &ireg, &oreg);
26 
27 	if (oreg.eflags & X86_EFLAGS_CF)
28 		return -1;	/* No MCA present */
29 
30 	set_fs(oreg.es);
31 	len = rdfs16(oreg.bx);
32 
33 	if (len > sizeof(boot_params.sys_desc_table))
34 		len = sizeof(boot_params.sys_desc_table);
35 
36 	copy_from_fs(&boot_params.sys_desc_table, oreg.bx, len);
37 	return 0;
38 }
39