sys/platform/pc64/x86_64/bios.c

   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  * $FreeBSD: head/sys/amd64/amd64/bios.c 148231 2005-07-21 09:48:37Z phk $
  28  */
  29
  30 /*
  31  * Subset of the i386 bios support code.  We cannot make bios16 nor bios32
  32  * calls, so we can leave that out.  However, searching for bios rom
  33  * signatures can be useful for locating tables, eg: powernow settings.
  34  */
  35
  36 #include <sys/param.h>
  37 #include <sys/systm.h>
  38 #include <sys/kernel.h>
  39 #include <vm/vm.h>
  40 #include <vm/pmap.h>
  41 #include <machine/vmparam.h>
  42 #include <machine/pc/bios.h>
  43
  44 #define BIOS_START      0xe0000
  45 #define BIOS_SIZE       0x20000
  46
  47 /*
  48  * bios_sigsearch
  49  *
  50  * Search some or all of the BIOS region for a signature string.
  51  *
  52  * (start)      Optional offset returned from this function
  53  *              (for searching for multiple matches), or NULL
  54  *              to start the search from the base of the BIOS.
  55  *              Note that this will be a _physical_ address in
  56  *              the range 0xe0000 - 0xfffff.
  57  * (sig)        is a pointer to the byte(s) of the signature.
  58  * (siglen)     number of bytes in the signature.
  59  * (paralen)    signature paragraph (alignment) size.
  60  * (sigofs)     offset of the signature within the paragraph.
  61  *
  62  * Returns the _physical_ address of the found signature, 0 if the
  63  * signature was not found.
  64  */
  65
  66 u_int32_t
  67 bios_sigsearch(u_int32_t start, u_char *sig, int siglen, int paralen, int sigofs)
  68 {
  69     u_char      *sp, *end;
  70
  71     /* compute the starting address */
  72     if ((start >= BIOS_START) && (start <= (BIOS_START + BIOS_SIZE))) {
  73         sp = (char *)BIOS_PADDRTOVADDR(start);
  74     } else if (start == 0) {
  75         sp = (char *)BIOS_PADDRTOVADDR(BIOS_START);
  76     } else {
  77         return 0;                               /* bogus start address */
  78     }
  79
  80     /* compute the end address */
  81     end = (u_char *)BIOS_PADDRTOVADDR(BIOS_START + BIOS_SIZE);
  82
  83     /* loop searching */
  84     while ((sp + sigofs + siglen) < end) {
  85
  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 }