e4f5866fd5
3MB of physical memory for heap instead of range between 1MB and 4MB. This makes this feature working with PAE and amd64 kernels, which are loaded at 2MB. Teach i386_copyin() to avoid using range allocated by heap in such case, so that it won't trash heap in the low memory conditions. This should make loading bzip2-compressed kernels/modules/mfs images generally useable, so that re@ team is welcome to evaluate merits of using this feature in the installation CDs. Valuable suggestions by: jhb
108 lines
3.2 KiB
C
108 lines
3.2 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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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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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 "libi386.h"
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#include "btxv86.h"
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vm_offset_t memtop, memtop_copyin;
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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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} __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 = memtop_copyin = 0x100000 + bios_extmem;
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}
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