Linux Kernel  3.7.1
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mca.c
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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 
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 
37  return 0;
38 }