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/biosmem.c,v 1.7 2003/08/25 23:28:31 obrien Exp $ 27 */ 28 /* 29 * Obtain memory configuration information from the BIOS 30 */ 31 #include <stand.h> 32 #include <machine/pc/bios.h> 33 #include <machine/psl.h> 34 #include "libi386.h" 35 #include "btxv86.h" 36 37 #define LOADER_HEAP_SIZE (1024 * 1024) 38 39 vm_offset_t memtop; 40 vm_offset_t heapbase; 41 u_int32_t bios_basemem, bios_extmem, bios_howmem; 42 43 static struct bios_smap smap; 44 45 void 46 bios_getmem(void) 47 { 48 int64_t v; 49 50 /* Parse system memory map */ 51 v86.ebx = 0; 52 do { 53 #ifdef COMCONSOLE_DEBUG 54 printf("GET SMAP %d: ", v86.ebx); 55 #endif 56 v86.ctl = V86_FLAGS; 57 v86.addr = 0x15; /* int 0x15 function 0xe820*/ 58 v86.eax = 0xe820; 59 v86.ecx = sizeof(struct bios_smap); 60 v86.edx = SMAP_SIG; 61 v86.es = VTOPSEG(&smap); 62 v86.edi = VTOPOFF(&smap); 63 v86int(); 64 #ifdef COMCONSOLE_DEBUG 65 printf("RESULT: EFL=%04x EAX=%08x SMAPTYPE %d BASE %08x%08x LEN %08x%08x\n", 66 v86.efl, v86.eax, smap.type, 67 (int)(smap.base >> 32), (int)smap.base, 68 (int)(smap.length >> 32), (int)smap.length); 69 #endif 70 if ((v86.efl & PSL_C) || (v86.eax != SMAP_SIG)) 71 break; 72 /* look for a low-memory segment that's large enough */ 73 if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0) && 74 (smap.length >= (512 * 1024))) { 75 bios_basemem = smap.length; 76 bios_howmem = 1; 77 } 78 /* look for the first segment in 'extended' memory */ 79 if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0x100000)) { 80 bios_extmem = smap.length; 81 } 82 } while (v86.ebx != 0); 83 84 /* Fall back to the old compatibility function for base memory */ 85 if (bios_basemem == 0) { 86 v86.ctl = 0; 87 v86.addr = 0x12; /* int 0x12 */ 88 v86int(); 89 90 bios_basemem = (v86.eax & 0xffff) * 1024; 91 bios_howmem = 2; 92 } 93 94 /* Fall back through several compatibility functions for extended memory */ 95 if (bios_extmem == 0) { 96 v86.ctl = V86_FLAGS; 97 v86.addr = 0x15; /* int 0x15 function 0xe801*/ 98 v86.eax = 0xe801; 99 v86int(); 100 if (!(v86.efl & PSL_C)) { 101 v = ((v86.ecx & 0xffff) + 102 ((int64_t)(v86.edx & 0xffff) * 64)) * 1024; 103 if (v > 0x40000000) 104 v = 0x40000000; 105 bios_extmem = v; 106 } 107 } 108 if (bios_extmem == 0) { 109 v86.ctl = 0; 110 v86.addr = 0x15; /* int 0x15 function 0x88*/ 111 v86.eax = 0x8800; 112 v86int(); 113 bios_extmem = (v86.eax & 0xffff) * 1024; 114 } 115 116 /* 117 * Set memtop to actual top of memory 118 * 119 * This is broken because the boot loader generally needs more than 16MB 120 * now but the extmem usually calculates to ~14-16MB (which is the fully 121 * segmented limit). Disk I/O will use bounce buffers. 122 * 123 * Hack it for now. 124 */ 125 #if 0 /* XXX ignored */ 126 memtop = 0x100000 + bios_extmem; 127 #endif 128 memtop = 64 * 1024 * 1024; 129 heapbase = memtop - LOADER_HEAP_SIZE; 130 } 131 132