627249c7b1
for our use. Use the same search order for BIOS memory size functions as the kernel will later use. Allow the loader to use all of the detected physical memory (this will greatly help people trying to load enormous memory disk images). More correctly handle running out of memory when loading an object. Use the end of base memory for the top of the heap, rather than blindly hoping that there is 384k left. Add copyrights to a couple of files I forgot.
106 lines
3.1 KiB
C
106 lines
3.1 KiB
C
/*-
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* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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/*
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* Obtain memory configuration information from the BIOS
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*/
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#include <stand.h>
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#include "btxv86.h"
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vm_offset_t memtop;
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u_int32_t bios_basemem, bios_extmem;
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#define SMAPSIG 0x534D4150
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struct smap {
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u_int64_t base;
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u_int64_t length;
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u_int32_t type;
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} __attribute__ ((packed));
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static struct smap smap;
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void
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bios_getmem(void)
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{
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/* Parse system memory map */
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v86.ebx = 0;
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do {
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v86.ctl = V86_FLAGS;
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v86.addr = 0x15; /* int 0x15 function 0xe820*/
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v86.eax = 0xe820;
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v86.ecx = sizeof(struct smap);
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v86.edx = SMAPSIG;
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v86.es = VTOPSEG(&smap);
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v86.edi = VTOPOFF(&smap);
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v86int();
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if ((v86.efl & 1) || (v86.eax != SMAPSIG))
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break;
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/* look for a low-memory segment that's large enough */
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if ((smap.type == 1) && (smap.base == 0) && (smap.length >= (512 * 1024)))
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bios_basemem = smap.length;
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/* look for the first segment in 'extended' memory */
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if ((smap.type == 1) && (smap.base == 0x100000)) {
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bios_extmem = smap.length;
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}
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} while (v86.ebx != 0);
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/* Fall back to the old compatibility function for base memory */
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if (bios_basemem == 0) {
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v86.ctl = 0;
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v86.addr = 0x12; /* int 0x12 */
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v86int();
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bios_basemem = (v86.eax & 0xffff) * 1024;
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}
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/* Fall back through several compatibility functions for extended memory */
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if (bios_extmem == 0) {
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v86.ctl = V86_FLAGS;
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v86.addr = 0x15; /* int 0x15 function 0xe801*/
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v86.eax = 0xe801;
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v86int();
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if (!(v86.efl & 1)) {
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bios_extmem = ((v86.ecx & 0xffff) + ((v86.edx & 0xffff) * 64)) * 1024;
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}
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}
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if (bios_extmem == 0) {
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v86.ctl = 0;
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v86.addr = 0x15; /* int 0x15 function 0x88*/
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v86.eax = 0x8800;
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v86int();
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bios_extmem = (v86.eax & 0xffff) * 1024;
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}
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/* Set memtop to actual top of memory */
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memtop = 0x100000 + bios_extmem;
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}
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