freebsd-skq/sys/boot/i386/libi386/biosmem.c
Michael Gmelin 29f2e5b5bc Improve memory detection in biosmem.c
- Add a quirk to allow ignoring e820 extended memory detection.
- Improve memory detection through e801.
- Add bootloader command "biosmem".

See differential revision for more details.

Reviewed by:	jhb, adrian
Approved by:	adrian
Differential Revision:  https://reviews.freebsd.org/D1741
2015-02-23 22:58:51 +00:00

242 lines
6.9 KiB
C

/*-
* Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
/*
* Obtain memory configuration information from the BIOS
*/
#include <stand.h>
#include <machine/pc/bios.h>
#include "bootstrap.h"
#include "libi386.h"
#include "btxv86.h"
vm_offset_t memtop, memtop_copyin, high_heap_base;
uint32_t bios_basemem, bios_extmem, high_heap_size;
static struct bios_smap_xattr smap;
/*
* Used to track which method was used to set BIOS memory
* regions.
*/
static uint8_t b_bios_probed;
#define B_BASEMEM_E820 0x1
#define B_BASEMEM_12 0x2
#define B_EXTMEM_E820 0x4
#define B_EXTMEM_E801 0x8
#define B_EXTMEM_8800 0x10
/*
* The minimum amount of memory to reserve in bios_extmem for the heap.
*/
#define HEAP_MIN (3 * 1024 * 1024)
/*
* Products in this list need quirks to detect
* memory correctly. You need both maker and product as
* reported by smbios.
*/
#define BQ_DISTRUST_E820_EXTMEM 0x1 /* e820 might not return useful
extended memory */
struct bios_getmem_quirks {
const char* bios_vendor;
const char* maker;
const char* product;
int quirk;
};
static struct bios_getmem_quirks quirks[] = {
{"coreboot", "Acer", "Peppy", BQ_DISTRUST_E820_EXTMEM},
{NULL, NULL, NULL, 0}
};
static int
bios_getquirks(void)
{
int i;
for (i=0; quirks[i].quirk != 0; ++i)
if (smbios_match(quirks[i].bios_vendor, quirks[i].maker,
quirks[i].product))
return (quirks[i].quirk);
return (0);
}
void
bios_getmem(void)
{
uint64_t size;
/* Parse system memory map */
v86.ebx = 0;
do {
v86.ctl = V86_FLAGS;
v86.addr = 0x15; /* int 0x15 function 0xe820*/
v86.eax = 0xe820;
v86.ecx = sizeof(struct bios_smap_xattr);
v86.edx = SMAP_SIG;
v86.es = VTOPSEG(&smap);
v86.edi = VTOPOFF(&smap);
v86int();
if ((V86_CY(v86.efl)) || (v86.eax != SMAP_SIG))
break;
/* look for a low-memory segment that's large enough */
if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0) &&
(smap.length >= (512 * 1024))) {
bios_basemem = smap.length;
b_bios_probed |= B_BASEMEM_E820;
}
/* look for the first segment in 'extended' memory */
if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0x100000) &&
!(bios_getquirks() & BQ_DISTRUST_E820_EXTMEM)) {
bios_extmem = smap.length;
b_bios_probed |= B_EXTMEM_E820;
}
/*
* Look for the largest segment in 'extended' memory beyond
* 1MB but below 4GB.
*/
if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base > 0x100000) &&
(smap.base < 0x100000000ull)) {
size = smap.length;
/*
* If this segment crosses the 4GB boundary, truncate it.
*/
if (smap.base + size > 0x100000000ull)
size = 0x100000000ull - smap.base;
if (size > high_heap_size) {
high_heap_size = size;
high_heap_base = smap.base;
}
}
} while (v86.ebx != 0);
/* Fall back to the old compatibility function for base memory */
if (bios_basemem == 0) {
v86.ctl = 0;
v86.addr = 0x12; /* int 0x12 */
v86int();
bios_basemem = (v86.eax & 0xffff) * 1024;
b_bios_probed |= B_BASEMEM_12;
}
/* Fall back through several compatibility functions for extended memory */
if (bios_extmem == 0) {
v86.ctl = V86_FLAGS;
v86.addr = 0x15; /* int 0x15 function 0xe801*/
v86.eax = 0xe801;
v86int();
if (!(V86_CY(v86.efl))) {
/*
* Clear high_heap; it may end up overlapping
* with the segment we're determining here.
* Let the default "steal stuff from top of
* bios_extmem" code below pick up on it.
*/
high_heap_size = 0;
high_heap_base = 0;
/*
* %cx is the number of 1KiB blocks between 1..16MiB.
* It can only be up to 0x3c00; if it's smaller then
* there's a PC AT memory hole so we can't treat
* it as contiguous.
*/
bios_extmem = (v86.ecx & 0xffff) * 1024;
if (bios_extmem == (1024 * 0x3c00))
bios_extmem += (v86.edx & 0xffff) * 64 * 1024;
/* truncate bios_extmem */
if (bios_extmem > 0x3ff00000)
bios_extmem = 0x3ff00000;
b_bios_probed |= B_EXTMEM_E801;
}
}
if (bios_extmem == 0) {
v86.ctl = 0;
v86.addr = 0x15; /* int 0x15 function 0x88*/
v86.eax = 0x8800;
v86int();
bios_extmem = (v86.eax & 0xffff) * 1024;
b_bios_probed |= B_EXTMEM_8800;
}
/* Set memtop to actual top of memory */
memtop = memtop_copyin = 0x100000 + bios_extmem;
/*
* If we have extended memory and did not find a suitable heap
* region in the SMAP, use the last 3MB of 'extended' memory as a
* high heap candidate.
*/
if (bios_extmem >= HEAP_MIN && high_heap_size < HEAP_MIN) {
high_heap_size = HEAP_MIN;
high_heap_base = memtop - HEAP_MIN;
}
}
static int
command_biosmem(int argc, char *argv[])
{
int bq = bios_getquirks();
printf("bios_basemem: 0x%llx\n", (unsigned long long) bios_basemem);
printf("bios_extmem: 0x%llx\n", (unsigned long long) bios_extmem);
printf("memtop: 0x%llx\n", (unsigned long long) memtop);
printf("high_heap_base: 0x%llx\n", (unsigned long long) high_heap_base);
printf("high_heap_size: 0x%llx\n", (unsigned long long) high_heap_size);
printf("bios_quirks: 0x%02x", bq);
if (bq & BQ_DISTRUST_E820_EXTMEM)
printf(" BQ_DISTRUST_E820_EXTMEM");
printf("\n");
printf("b_bios_probed: 0x%02x", (int) b_bios_probed);
if (b_bios_probed & B_BASEMEM_E820)
printf(" B_BASEMEM_E820");
if (b_bios_probed & B_BASEMEM_12)
printf(" B_BASEMEM_12");
if (b_bios_probed & B_EXTMEM_E820)
printf(" B_EXTMEM_E820");
if (b_bios_probed & B_EXTMEM_E801)
printf(" B_EXTMEM_E801");
if (b_bios_probed & B_EXTMEM_8800)
printf(" B_EXTMEM_8800");
printf("\n");
return (CMD_OK);
}
COMMAND_SET(biosmem, "biosmem", "show BIOS memory setup", command_biosmem);