biossmap.c revision 137419 
1/*-
2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
17 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
24 * SUCH DAMAGE.
25 */
26
27#include <sys/cdefs.h>
28__FBSDID("$FreeBSD: head/sys/boot/i386/libi386/biossmap.c 137419 2004-11-08 23:59:44Z peter $");
29
30/*
31 * Obtain memory configuration information from the BIOS
32 */
33#include <stand.h>
34#include <sys/param.h>
35#include <sys/linker.h>
36#include <machine/metadata.h>
37#include "bootstrap.h"
38#include "libi386.h"
39#include "btxv86.h"
40
41#define SMAPSIG	0x534D4150
42
43struct smap {
44	u_int64_t	base;
45	u_int64_t	length;
46	u_int32_t	type;
47} __packed;
48
49static struct smap smap;
50
51static struct smap *smapbase;
52static int smaplen;
53
54void
55bios_getsmap(void)
56{
57	int n;
58
59	n = 0;
60	smaplen = 0;
61	/* Count up segments in system memory map */
62	v86.ebx = 0;
63	do {
64		v86.ctl = V86_FLAGS;
65		v86.addr = 0x15;		/* int 0x15 function 0xe820*/
66		v86.eax = 0xe820;
67		v86.ecx = sizeof(struct smap);
68		v86.edx = SMAPSIG;
69		v86.es = VTOPSEG(&smap);
70		v86.edi = VTOPOFF(&smap);
71		v86int();
72		if ((v86.efl & 1) || (v86.eax != SMAPSIG))
73			break;
74		n++;
75	} while (v86.ebx != 0);
76	if (n == 0)
77		return;
78	n += 10;	/* spare room */
79	smapbase = malloc(n * sizeof(*smapbase));
80
81	/* Save system memory map */
82	v86.ebx = 0;
83	do {
84		v86.ctl = V86_FLAGS;
85		v86.addr = 0x15;		/* int 0x15 function 0xe820*/
86		v86.eax = 0xe820;
87		v86.ecx = sizeof(struct smap);
88		v86.edx = SMAPSIG;
89		v86.es = VTOPSEG(&smapbase[smaplen]);
90		v86.edi = VTOPOFF(&smapbase[smaplen]);
91		v86int();
92		smaplen++;
93		if ((v86.efl & 1) || (v86.eax != SMAPSIG))
94			break;
95	} while (v86.ebx != 0 && smaplen < n);
96}
97void
98bios_addsmapdata(struct preloaded_file *kfp)
99{
100	int len;
101
102	if (smapbase == 0 || smaplen == 0)
103		return;
104	len = smaplen * sizeof(*smapbase);
105	file_addmetadata(kfp, MODINFOMD_SMAP, len, smapbase);
106}
107