sys/boot/pc32/libi386/biossmap.c

   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  * $FreeBSD: src/sys/boot/i386/libi386/biossmap.c,v 1.2 2003/08/25 23:28:31 obrien Exp $
  27  */
  28
  29 /*
  30  * Obtain memory configuration information from the BIOS
  31  */
  32 #include <stand.h>
  33 #include <sys/param.h>
  34 #include <sys/linker.h>
  35 #include <machine/metadata.h>
  36 #include <machine/pc/bios.h>
  37 #include <machine/psl.h>
  38 #include "bootstrap.h"
  39 #include "libi386.h"
  40 #include "btxv86.h"
  41
  42 #define SMAPSIG 0x534D4150
  43
  44 struct smap {
  45         u_int64_t       base;
  46         u_int64_t       length;
  47         u_int32_t       type;
  48 } __packed;
  49
  50 static struct smap smap;
  51
  52 static struct smap *smapbase;
  53 static int smaplen;
  54
  55 void
  56 bios_getsmap(void)
  57 {
  58         int n;
  59
  60         n = 0;
  61         smaplen = 0;
  62         /* Count up segments in system memory map */
  63         v86.ebx = 0;
  64         do {
  65                 v86.ctl = V86_FLAGS;
  66                 v86.addr = 0x15;                /* int 0x15 function 0xe820*/
  67                 v86.eax = 0xe820;
  68                 v86.ecx = sizeof(struct smap);
  69                 v86.edx = SMAPSIG;
  70                 v86.es = VTOPSEG(&smap);
  71                 v86.edi = VTOPOFF(&smap);
  72                 v86int();
  73                 if ((v86.efl & PSL_C) || (v86.eax != SMAPSIG))
  74                         break;
  75                 n++;
  76         } while (v86.ebx != 0);
  77         if (n == 0)
  78                 return;
  79         n += 10;        /* spare room */
  80         smapbase = malloc(n * sizeof(*smapbase));
  81
  82         /* Save system memory map */
  83         v86.ebx = 0;
  84         do {
  85                 v86.ctl = V86_FLAGS;
  86                 v86.addr = 0x15;                /* int 0x15 function 0xe820*/
  87                 v86.eax = 0xe820;
  88                 v86.ecx = sizeof(struct smap);
  89                 v86.edx = SMAPSIG;
  90                 v86.es = VTOPSEG(&smap);
  91                 v86.edi = VTOPOFF(&smap);
  92                 v86int();
  93
  94                 /*
  95                  * Our heap is now in high memory and must be removed from
  96                  * the smap so the kernel does not blow away passed-in
  97                  * arguments, smap, kenv, etc.
  98                  *
  99                  * This wastes a little memory.
 100                  */
 101                 if (smap.type == SMAP_TYPE_MEMORY &&
 102                     smap.base + smap.length > heapbase &&
 103                     smap.base < memtop) {
 104                         if (smap.base <= heapbase) {
 105                                 if (heapbase - smap.base) {
 106                                         smapbase[smaplen] = smap;
 107                                         smapbase[smaplen].length =
 108                                                 heapbase - smap.base;
 109                                         ++smaplen;
 110                                 }
 111                         }
 112                         if (smap.base + smap.length >= memtop) {
 113                                 if (smap.base + smap.length - memtop) {
 114                                         smapbase[smaplen] = smap;
 115                                         smapbase[smaplen].base = memtop;
 116                                         smapbase[smaplen].length =
 117                                                 smap.base + smap.length -
 118                                                 memtop;
 119                                         ++smaplen;
 120                                 }
 121                         }
 122                 } else {
 123                         smapbase[smaplen] = smap;
 124                         ++smaplen;
 125                 }
 126                 if ((v86.efl & PSL_C) || (v86.eax != SMAPSIG))
 127                         break;
 128         } while (v86.ebx != 0 && smaplen < n);
 129 }
 130 void
 131 bios_addsmapdata(struct preloaded_file *kfp)
 132 {
 133         int len;
 134
 135         if (smapbase == NULL || smaplen == 0)
 136                 return;
 137         len = smaplen * sizeof(*smapbase);
 138         file_addmetadata(kfp, MODINFOMD_SMAP, len, smapbase);
 139         /* Temporary compatibility with older development kernels */
 140         file_addmetadata(kfp, 0x0009, len, smapbase);
 141 }