memdisk/msetup.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2001-2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
   8  *   Boston MA 02111-1307, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 /*
  14  * msetup.c
  15  *
  16  * Initialization code for memory-based disk
  17  */
  18
  19 #include <stdint.h>
  20 #ifdef TEST
  21 # include <string.h>
  22 # include <stdio.h>
  23 #else
  24 # include "memdisk.h"
  25 # include "conio.h"
  26 #endif
  27 #include "e820.h"
  28
  29 uint32_t dos_mem  = 0;          /* 0-1MB */
  30 uint32_t low_mem  = 0;          /* 1-16MB */
  31 uint32_t high_mem = 0;          /* 16+ MB */
  32
  33 #ifndef TEST
  34
  35 static inline int get_e820(void)
  36 {
  37   struct e820_info {
  38     uint64_t base;
  39     uint64_t len;
  40     uint32_t type;
  41     uint32_t extattr;
  42   } *buf = sys_bounce;
  43   uint32_t copied;
  44   int range_count = 0;
  45   com32sys_t regs;
  46
  47   memset(&regs, 0, sizeof regs);
  48   memset(buf, 0, sizeof *buf);
  49   buf->extattr = 1;
  50
  51   do {
  52     regs.eax.l = 0x0000e820;
  53     regs.ecx.l = sizeof(*buf);
  54     regs.edx.l = 0x534d4150;
  55     regs.edi.w[0] = OFFS(buf);
  56     regs.es = SEG(buf);
  57
  58     syscall(0x15, &regs, &regs);
  59     copied = (regs.eflags.l & 1) ? 0 : regs.ecx.l;
  60
  61     if ( regs.eax.l != 0x534d4150 || copied < 20 )
  62       break;
  63
  64     if ( copied < 24 )
  65       buf->extattr = 1;
  66
  67     printf("e820: %08x%08x %08x%08x %d [%x]\n",
  68            (uint32_t)(buf->base >> 32), (uint32_t)buf->base,
  69            (uint32_t)(buf->len >> 32), (uint32_t)buf->len,
  70            buf->type, buf->extattr);
  71
  72     if ( !(buf->extattr & 1) )
  73       continue;                 /* Disabled range, just ignore */
  74
  75     insertrange(buf->base, buf->len, buf->type, buf->extattr);
  76     range_count++;
  77
  78   } while ( regs.ebx.l );
  79
  80   return !range_count;
  81 }
  82
  83 static inline void get_dos_mem(void)
  84 {
  85   com32sys_t regs;
  86
  87   memset(&regs, 0, sizeof regs);
  88   syscall(0x12, &regs, &regs);
  89   insertrange(0, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1, 1);
  90   printf(" DOS: %d K\n", regs.eax.w[0]);
  91 }
  92
  93 static inline int get_e801(void)
  94 {
  95   int err;
  96   com32sys_t regs;
  97
  98   memset(&regs, 0, sizeof regs);
  99
 100   regs.eax.w[0] = 0xe801;
 101   syscall(0x15, &regs, &regs);
 102
 103   if ( !(err = regs.eflags.l & 1) ) {
 104     if ( regs.eax.w[0] ) {
 105       insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1, 1);
 106     }
 107     if ( regs.ebx.w[0] ) {
 108       insertrange(0x1000000, (uint64_t)((uint32_t)regs.ebx.w[0] << 16), 1, 1);
 109     }
 110
 111     printf("e801: %04x %04x\n", regs.eax.w[0], regs.ebx.w[0]);
 112   }
 113
 114   return err;
 115 }
 116
 117 static inline int get_88(void)
 118 {
 119   com32sys_t regs;
 120   int err;
 121
 122   memset(&regs, 0, sizeof regs);
 123
 124   regs.eax.b[1] = 0x88;
 125   syscall(0x15, &regs, &regs);
 126
 127
 128   if ( !(err = regs.eflags.l & 1) ) {
 129     if ( regs.eax.w[0] ) {
 130       insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1, 1);
 131     }
 132
 133     printf("  88: %04x\n", regs.eax.w[0]);
 134   }
 135
 136   return err;
 137 }
 138
 139 void get_mem(void)
 140 {
 141   if ( get_e820() ) {
 142     get_dos_mem();
 143     if ( get_e801() ) {
 144       if ( get_88() ) {
 145         puts("MEMDISK: Unable to obtain memory map\n");
 146         die();
 147       }
 148     }
 149   }
 150 }
 151
 152 #endif  /* TEST */
 153
 154 #define PW(x) (1ULL << (x))
 155
 156 void parse_mem(void)
 157 {
 158   struct e820range *ep;
 159
 160   dos_mem = low_mem = high_mem = 0;
 161
 162   /* Derive "dos mem", "high mem", and "low mem" from the range array */
 163   for ( ep = ranges ; ep->type != -1U ; ep++ ) {
 164     if ( ep->type == 1 ) {
 165       /* Only look at memory ranges */
 166       if ( ep->start == 0 ) {
 167         if ( ep[1].start > PW(20) )
 168           dos_mem = PW(20);
 169         else
 170           dos_mem = ep[1].start;
 171       }
 172       if ( ep->start <= PW(20) && ep[1].start > PW(20) ) {
 173         if ( ep[1].start > PW(24) )
 174           low_mem = PW(24) - PW(20);
 175         else
 176           low_mem = ep[1].start - PW(20);
 177       }
 178       if ( ep->start <= PW(24) && ep[1].start > PW(24) ) {
 179         if ( ep[1].start > PW(32) )
 180           high_mem = PW(32) - PW(24);
 181         else
 182           high_mem = ep[1].start - PW(24);
 183       }
 184     }
 185   }
 186 }