2 * Copyright (c) 1998 Michael Smith <msmith@freebsd.org>
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
27 #include <sys/cdefs.h>
28 __FBSDID("$FreeBSD$");
31 * Obtain memory configuration information from the BIOS
34 #include <machine/pc/bios.h>
35 #include "bootstrap.h"
40 vm_offset_t memtop, memtop_copyin, high_heap_base;
41 uint32_t bios_basemem, bios_extmem, high_heap_size;
43 static struct bios_smap_xattr smap;
46 * Used to track which method was used to set BIOS memory
49 static uint8_t b_bios_probed;
50 #define B_BASEMEM_E820 0x1
51 #define B_BASEMEM_12 0x2
52 #define B_EXTMEM_E820 0x4
53 #define B_EXTMEM_E801 0x8
54 #define B_EXTMEM_8800 0x10
57 * The minimum amount of memory to reserve in bios_extmem for the heap.
59 #define HEAP_MIN (64 * 1024 * 1024)
62 * Products in this list need quirks to detect
63 * memory correctly. You need both maker and product as
66 /* e820 might not return useful extended memory */
67 #define BQ_DISTRUST_E820_EXTMEM 0x1
68 struct bios_getmem_quirks {
69 const char *bios_vendor;
75 static struct bios_getmem_quirks quirks[] = {
76 {"coreboot", "Acer", "Peppy", BQ_DISTRUST_E820_EXTMEM},
77 {"coreboot", "Dell", "Wolf", BQ_DISTRUST_E820_EXTMEM},
86 for (i = 0; quirks[i].quirk != 0; ++i) {
87 if (smbios_match(quirks[i].bios_vendor, quirks[i].maker,
89 return (quirks[i].quirk);
100 /* Parse system memory map */
104 v86.addr = 0x15; /* int 0x15 function 0xe820 */
106 v86.ecx = sizeof(struct bios_smap_xattr);
108 v86.es = VTOPSEG(&smap);
109 v86.edi = VTOPOFF(&smap);
111 if ((V86_CY(v86.efl)) || (v86.eax != SMAP_SIG))
113 /* look for a low-memory segment that's large enough */
114 if ((smap.type == SMAP_TYPE_MEMORY) && (smap.base == 0) &&
115 (smap.length >= (512 * 1024))) {
116 bios_basemem = smap.length;
117 b_bios_probed |= B_BASEMEM_E820;
120 /* look for the first segment in 'extended' memory */
121 if ((smap.type == SMAP_TYPE_MEMORY) &&
122 (smap.base == 0x100000) &&
123 !(bios_getquirks() & BQ_DISTRUST_E820_EXTMEM)) {
124 bios_extmem = smap.length;
125 b_bios_probed |= B_EXTMEM_E820;
129 * Look for the highest segment in 'extended' memory beyond
132 if ((smap.type == SMAP_TYPE_MEMORY) &&
133 (smap.base > 0x100000) &&
134 (smap.base < 0x100000000ull)) {
138 * If this segment crosses the 4GB boundary,
141 if (smap.base + size > 0x100000000ull)
142 size = 0x100000000ull - smap.base;
145 * To make maximum space for the kernel and the modules,
146 * set heap to use highest HEAP_MIN bytes below 4GB.
148 if (high_heap_base < smap.base && size >= HEAP_MIN) {
149 high_heap_base = smap.base + size - HEAP_MIN;
150 high_heap_size = HEAP_MIN;
153 } while (v86.ebx != 0);
155 /* Fall back to the old compatibility function for base memory */
156 if (bios_basemem == 0) {
158 v86.addr = 0x12; /* int 0x12 */
161 bios_basemem = (v86.eax & 0xffff) * 1024;
162 b_bios_probed |= B_BASEMEM_12;
166 * Fall back through several compatibility functions for extended
169 if (bios_extmem == 0) {
171 v86.addr = 0x15; /* int 0x15 function 0xe801 */
174 if (!(V86_CY(v86.efl))) {
176 * Clear high_heap; it may end up overlapping
177 * with the segment we're determining here.
178 * Let the default "steal stuff from top of
179 * bios_extmem" code below pick up on it.
185 * %cx is the number of 1KiB blocks between 1..16MiB.
186 * It can only be up to 0x3c00; if it's smaller then
187 * there's a PC AT memory hole so we can't treat
190 bios_extmem = (v86.ecx & 0xffff) * 1024;
191 if (bios_extmem == (1024 * 0x3c00))
192 bios_extmem += (v86.edx & 0xffff) * 64 * 1024;
194 /* truncate bios_extmem */
195 if (bios_extmem > 0x3ff00000)
196 bios_extmem = 0x3ff00000;
198 b_bios_probed |= B_EXTMEM_E801;
201 if (bios_extmem == 0) {
203 v86.addr = 0x15; /* int 0x15 function 0x88 */
206 bios_extmem = (v86.eax & 0xffff) * 1024;
207 b_bios_probed |= B_EXTMEM_8800;
210 /* Set memtop to actual top of memory */
211 if (high_heap_size != 0) {
212 memtop = memtop_copyin = high_heap_base;
214 memtop = memtop_copyin = 0x100000 + bios_extmem;
218 * If we have extended memory and did not find a suitable heap
219 * region in the SMAP, use the last HEAP_MIN of 'extended' memory as a
220 * high heap candidate.
222 if (bios_extmem >= HEAP_MIN && high_heap_size < HEAP_MIN) {
223 high_heap_size = HEAP_MIN;
224 high_heap_base = memtop - HEAP_MIN;
225 memtop = memtop_copyin = high_heap_base;
230 command_biosmem(int argc, char *argv[])
232 int bq = bios_getquirks();
234 printf("bios_basemem: 0x%llx\n", (unsigned long long)bios_basemem);
235 printf("bios_extmem: 0x%llx\n", (unsigned long long)bios_extmem);
236 printf("memtop: 0x%llx\n", (unsigned long long)memtop);
237 printf("high_heap_base: 0x%llx\n", (unsigned long long)high_heap_base);
238 printf("high_heap_size: 0x%llx\n", (unsigned long long)high_heap_size);
239 printf("bios_quirks: 0x%02x", bq);
240 if (bq & BQ_DISTRUST_E820_EXTMEM)
241 printf(" BQ_DISTRUST_E820_EXTMEM");
243 printf("b_bios_probed: 0x%02x", (int)b_bios_probed);
244 if (b_bios_probed & B_BASEMEM_E820)
245 printf(" B_BASEMEM_E820");
246 if (b_bios_probed & B_BASEMEM_12)
247 printf(" B_BASEMEM_12");
248 if (b_bios_probed & B_EXTMEM_E820)
249 printf(" B_EXTMEM_E820");
250 if (b_bios_probed & B_EXTMEM_E801)
251 printf(" B_EXTMEM_E801");
252 if (b_bios_probed & B_EXTMEM_8800)
253 printf(" B_EXTMEM_8800");
259 COMMAND_SET(biosmem, "biosmem", "show BIOS memory setup", command_biosmem);