f1a6fd5d07
heap when using a range above 1MB. Previously the loader would always use the last 3MB in the first memory range above 1MB for the heap. However, this memory range is also where the kernel and any modules are loaded. If this memory range is "small", then using the high 3MB for the heap may not leave enough room for the kernel and modules. Now the loader will use any range below 4GB for the heap, and the logic to choose the "high" heap region has moved into biosmem.c. It sets two variables that the loader can use for a high heap if it desires. When a high heap is enabled (BZIP2, FireWire, GPT, or ZFS), then the following memory ranges are preferred for the heap in order from best to worst: - The largest memory region in the SMAP with a start address greater than 1MB. The memory region must be at least 3MB in length. This leaves the region starting at 1MB purely for use by the kernel and modules. - The last 3MB of the memory region starting at 1MB if it is at least 3MB in size. This matches the current behavior except that the current loader would break horribly if the first region was not at least 3MB in size. - The memory range from the end of the loader up to the 640k window. This is the range the loader uses when none of the high-heap-requesting options are enabled. Tested by: hrs MFC after: 1 week
136 lines
4.1 KiB
C
136 lines
4.1 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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#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 <machine/pc/bios.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, high_heap_base;
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uint32_t bios_basemem, bios_extmem, high_heap_size;
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static struct bios_smap smap;
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/*
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* The minimum amount of memory to reserve in bios_extmem for the heap.
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*/
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#define HEAP_MIN (3 * 1024 * 1024)
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void
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bios_getmem(void)
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{
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uint64_t size;
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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 bios_smap);
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v86.edx = SMAP_SIG;
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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 != SMAP_SIG))
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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 == SMAP_TYPE_MEMORY) && (smap.base == 0) &&
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(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 == SMAP_TYPE_MEMORY) && (smap.base == 0x100000)) {
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bios_extmem = smap.length;
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}
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/*
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* Look for the largest segment in 'extended' memory beyond
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* 1MB but below 4GB.
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*/
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if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base > 0x100000) &&
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(smap.base < 0x100000000ull)) {
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size = smap.length;
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/*
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* If this segment crosses the 4GB boundary, truncate it.
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*/
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if (smap.base + size > 0x100000000ull)
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size = 0x100000000ull - smap.base;
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if (size > high_heap_size) {
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high_heap_size = size;
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high_heap_base = smap.base;
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}
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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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* If we have extended memory and did not find a suitable heap
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* region in the SMAP, use the last 3MB of 'extended' memory as a
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* high heap candidate.
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*/
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if (bios_extmem >= HEAP_MIN && high_heap_size < HEAP_MIN) {
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high_heap_size = HEAP_MIN;
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high_heap_base = memtop - HEAP_MIN;
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}
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}
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