bios.c revision 135689 
1/*-
2 * Copyright (c) 1997 Michael Smith
3 * Copyright (c) 1998 Jonathan Lemon
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__FBSDID("$FreeBSD: head/sys/amd64/amd64/bios.c 135689 2004-09-24 00:42:36Z peter $");
30
31/*
32 * Subset of the i386 bios support code.  We cannot make bios16 nor bios32
33 * calls, so we can leave that out.  However, searching for bios rom
34 * signatures can be useful for locating tables, eg: powernow settings.
35 */
36
37#include <sys/param.h>
38#include <sys/systm.h>
39#include <sys/kernel.h>
40#include <machine/pc/bios.h>
41
42#define BIOS_START	0xe0000
43#define BIOS_SIZE	0x20000
44
45/*
46 * bios_sigsearch
47 *
48 * Search some or all of the BIOS region for a signature string.
49 *
50 * (start)	Optional offset returned from this function
51 *		(for searching for multiple matches), or NULL
52 *		to start the search from the base of the BIOS.
53 *		Note that this will be a _physical_ address in
54 *		the range 0xe0000 - 0xfffff.
55 * (sig)	is a pointer to the byte(s) of the signature.
56 * (siglen)	number of bytes in the signature.
57 * (paralen)	signature paragraph (alignment) size.
58 * (sigofs)	offset of the signature within the paragraph.
59 *
60 * Returns the _physical_ address of the found signature, 0 if the
61 * signature was not found.
62 */
63
64u_int32_t
65bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen, int sigofs)
66{
67    u_char	*sp, *end;
68
69    /* compute the starting address */
70    if ((start >= BIOS_START) && (start <= (BIOS_START + BIOS_SIZE))) {
71	sp = (char *)BIOS_PADDRTOVADDR(start);
72    } else if (start == 0) {
73	sp = (char *)BIOS_PADDRTOVADDR(BIOS_START);
74    } else {
75	return 0;				/* bogus start address */
76    }
77
78    /* compute the end address */
79    end = (u_char *)BIOS_PADDRTOVADDR(BIOS_START + BIOS_SIZE);
80
81    /* loop searching */
82    while ((sp + sigofs + siglen) < end) {
83
84	/* compare here */
85	if (!bcmp(sp + sigofs, sig, siglen)) {
86	    /* convert back to physical address */
87	    return((u_int32_t)BIOS_VADDRTOPADDR(sp));
88	}
89	sp += paralen;
90    }
91    return(0);
92}
93
94const u_char *
95bios_string(u_int from, u_int to, const u_char *string, int len)
96{
97	const char *t, *te;
98
99	if (len == 0)
100		len = strlen(string);
101	t = (const char *)(KERNBASE + from);
102	te = (const char *)(KERNBASE + to);
103	for (; t <= te; t++)
104		if (!memcmp(string, t, len))
105			return (t);
106	return (NULL);
107}
108