1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 1997 Michael Smith
5 * Copyright (c) 1998 Jonathan Lemon
6 * All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 #include <sys/cdefs.h>
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 <vm/vm.h>
41 #include <vm/pmap.h>
42 #include <machine/vmparam.h>
43 #include <machine/pc/bios.h>
44
45 #define BIOS_START 0xe0000
46 #define BIOS_SIZE 0x20000
47
48 /*
49 * bios_sigsearch
50 *
51 * Search some or all of the BIOS region for a signature string.
52 *
53 * (start) Optional offset returned from this function
54 * (for searching for multiple matches), or NULL
55 * to start the search from the base of the BIOS.
56 * Note that this will be a _physical_ address in
57 * the range 0xe0000 - 0xfffff.
58 * (sig) is a pointer to the byte(s) of the signature.
59 * (siglen) number of bytes in the signature.
60 * (paralen) signature paragraph (alignment) size.
61 * (sigofs) offset of the signature within the paragraph.
62 *
63 * Returns the _physical_ address of the found signature, 0 if the
64 * signature was not found.
65 */
66
67 u_int32_t
bios_sigsearch(u_int32_t start,u_char * sig,int siglen,int paralen,int sigofs)68 bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen, int sigofs)
69 {
70 u_char *sp, *end;
71
72 /* compute the starting address */
73 if ((start >= BIOS_START) && (start <= (BIOS_START + BIOS_SIZE))) {
74 sp = (char *)BIOS_PADDRTOVADDR(start);
75 } else if (start == 0) {
76 sp = (char *)BIOS_PADDRTOVADDR(BIOS_START);
77 } else {
78 return 0; /* bogus start address */
79 }
80
81 /* compute the end address */
82 end = (u_char *)BIOS_PADDRTOVADDR(BIOS_START + BIOS_SIZE);
83
84 /* loop searching */
85 while ((sp + sigofs + siglen) < end) {
86 /* compare here */
87 if (!bcmp(sp + sigofs, sig, siglen)) {
88 /* convert back to physical address */
89 return((u_int32_t)(uintptr_t)BIOS_VADDRTOPADDR(sp));
90 }
91 sp += paralen;
92 }
93 return(0);
94 }
95