LXR linux/arch/x86/boot/mca.c

   1/* -*- 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 * Get the MCA system description table
  13 */
  14
  15#include "boot.h"
  16
  17int query_mca(void)
  18{
  19        u8 err;
  20        u16 es, bx, len;
  21
  22        asm("pushw %%es ; "
  23            "int $0x15 ; "
  24            "setc %0 ; "
  25            "movw %%es, %1 ; "
  26            "popw %%es"
  27            : "=acd" (err), "=acdSD" (es), "=b" (bx)
  28            : "a" (0xc000));
  29
  30        if (err)
  31                return -1;      /* No MCA present */
  32
  33        set_fs(es);
  34        len = rdfs16(bx);
  35
  36        if (len > sizeof(boot_params.sys_desc_table))
  37                len = sizeof(boot_params.sys_desc_table);
  38
  39        copy_from_fs(&boot_params.sys_desc_table, bx, len);
  40        return 0;
  41}
  42