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 #include "memdisk.h"
  21 #include "conio.h"
  22 #include "e820.h"
  23
  24 static inline int get_e820(void)
  25 {
  26   struct e820_info {
  27     uint64_t base;
  28     uint64_t len;
  29     uint32_t type;
  30   } *buf = sys_bounce;
  31   uint32_t copied;
  32   int range_count = 0;
  33   com32sys_t regs;
  34
  35   memset(&regs, 0, sizeof regs);
  36
  37   do {
  38     regs.eax.l = 0x0000e820;
  39     regs.ecx.l = sizeof(*buf);
  40     regs.edx.l = 0x534d4150;
  41     regs.edi.w[0] = OFFS(buf);
  42     regs.es = SEG(buf);
  43
  44     syscall(0x15, &regs, &regs);
  45     copied = (regs.eflags.l & 1) ? 0 : regs.ecx.l;
  46
  47     if ( regs.eax.l != 0x534d4150 || copied < 20 )
  48       break;
  49
  50     printf("e820: %08x%08x %08x%08x %d\n",
  51            (uint32_t)(buf->base >> 32), (uint32_t)buf->base,
  52            (uint32_t)(buf->len >> 32), (uint32_t)buf->len,
  53            buf->type);
  54
  55     insertrange(buf->base, buf->len, buf->type);
  56     range_count++;
  57
  58   } while ( regs.ebx.l );
  59
  60   return !range_count;
  61 }
  62
  63 static inline void get_dos_mem(void)
  64 {
  65   com32sys_t regs;
  66
  67   memset(&regs, 0, sizeof regs);
  68   syscall(0x12, &regs, &regs);
  69   insertrange(0, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1);
  70   printf(" DOS: %d K\n", regs.eax.w[0]);
  71 }
  72
  73 static inline int get_e801(void)
  74 {
  75   int err;
  76   com32sys_t regs;
  77
  78   memset(&regs, 0, sizeof regs);
  79
  80   regs.eax.w[0] = 0xe801;
  81   syscall(0x15, &regs, &regs);
  82
  83   if ( !(err = regs.eflags.l & 1) ) {
  84     if ( regs.eax.w[0] ) {
  85       insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1);
  86     }
  87     if ( regs.ebx.w[0] ) {
  88       insertrange(0x1000000, (uint64_t)((uint32_t)regs.ebx.w[0] << 16), 1);
  89     }
  90
  91     printf("e801: %04x %04x\n", regs.eax.w[0], regs.ebx.w[0]);
  92   }
  93
  94   return err;
  95 }
  96
  97 static inline int get_88(void)
  98 {
  99   com32sys_t regs;
 100   int err;
 101
 102   memset(&regs, 0, sizeof regs);
 103
 104   regs.eax.b[1] = 0x88;
 105   syscall(0x15, &regs, &regs);
 106
 107
 108   if ( !(err = regs.eflags.l & 1) ) {
 109     if ( regs.eax.w[0] ) {
 110       insertrange(0x100000, (uint64_t)((uint32_t)regs.eax.w[0] << 10), 1);
 111     }
 112
 113     printf("  88: %04x\n", regs.eax.w[0]);
 114   }
 115
 116   return err;
 117 }
 118
 119 uint32_t dos_mem  = 0;          /* 0-1MB */
 120 uint32_t low_mem  = 0;          /* 1-16MB */
 121 uint32_t high_mem = 0;          /* 16+ MB */
 122
 123 void get_mem(void)
 124 {
 125   if ( get_e820() ) {
 126     get_dos_mem();
 127     if ( get_e801() ) {
 128       if ( get_88() ) {
 129         puts("MEMDISK: Unable to obtain memory map\n");
 130         die();
 131       }
 132     }
 133   }
 134 }
 135
 136 #define PW(x) (1ULL << (x))
 137
 138 void parse_mem(void)
 139 {
 140   struct e820range *ep;
 141
 142   dos_mem = low_mem = high_mem = 0;
 143
 144   /* Derive "dos mem", "high mem", and "low mem" from the range array */
 145   for ( ep = ranges ; ep->type != -1 ; ep++ ) {
 146     if ( ep->type == 1 ) {
 147       /* Only look at memory ranges */
 148       if ( ep->start == 0 ) {
 149         if ( ep[1].start > PW(20) )
 150           dos_mem = PW(20);
 151         else
 152           dos_mem = ep[1].start;
 153       }
 154       if ( ep->start <= PW(20) && ep[1].start > PW(20) ) {
 155         if ( ep[1].start > PW(24) )
 156           low_mem = PW(24) - PW(20);
 157         else
 158           low_mem = ep[1].start - PW(20);
 159       }
 160       if ( ep->start <= PW(24) && ep[1].start > PW(24) ) {
 161         if ( ep[1].start > PW(32) )
 162           high_mem = PW(32) - PW(24);
 163         else
 164           high_mem = ep[1].start - PW(24);
 165       }
 166     }
 167   }
 168 }