1 /* ----------------------------------------------------------------------- * 2 * 3 * Copyright 2007-2009 H. Peter Anvin - All Rights Reserved 4 * Copyright 2009 H. Peter Anvin - All Rights Reserved 5 * 6 * Permission is hereby granted, free of charge, to any person 7 * obtaining a copy of this software and associated documentation 8 * files (the "Software"), to deal in the Software without 9 * restriction, including without limitation the rights to use, 10 * copy, modify, merge, publish, distribute, sublicense, and/or 11 * sell copies of the Software, and to permit persons to whom 12 * the Software is furnished to do so, subject to the following 13 * conditions: 14 * 15 * The above copyright notice and this permission notice shall 16 * be included in all copies or substantial portions of the Software. 17 * 18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 19 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES 20 * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 21 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT 22 * HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, 23 * WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING 24 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR 25 * OTHER DEALINGS IN THE SOFTWARE. 26 * 27 * ----------------------------------------------------------------------- */ 28 29 /* 30 * mem.c 31 * 32 * Obtain a memory map for a Multiboot OS 33 * 34 * This differs from the libcom32 memory map functions in that it doesn't 35 * attempt to filter out memory regions... 36 */ 37 38 #include "mboot.h" 39 #include <com32.h> 40 41 struct e820_entry { 42 uint64_t start; 43 uint64_t len; 44 uint32_t type; 45 }; 46 47 #define RANGE_ALLOC_BLOCK 128 48 49 static int mboot_scan_memory(struct AddrRangeDesc **ardp, uint32_t * dosmem) 50 { 51 com32sys_t ireg, oreg; 52 struct e820_entry *e820buf; 53 struct AddrRangeDesc *ard; 54 size_t ard_count, ard_space; 55 int rv = 0; 56 57 /* Use INT 12h to get DOS memory */ 58 __intcall(0x12, &__com32_zero_regs, &oreg); 59 *dosmem = oreg.eax.w[0] << 10; 60 if (*dosmem < 32 * 1024 || *dosmem > 640 * 1024) { 61 /* INT 12h reports nonsense... now what? */ 62 uint16_t ebda_seg = *(uint16_t *) 0x40e; 63 if (ebda_seg >= 0x8000 && ebda_seg < 0xa000) 64 *dosmem = ebda_seg << 4; 65 else 66 *dosmem = 640 * 1024; /* Hope for the best... */ 67 } 68 69 e820buf = lmalloc(sizeof(*e820buf)); 70 if (!e820buf) 71 return 0; 72 73 /* Allocate initial space */ 74 *ardp = ard = malloc(RANGE_ALLOC_BLOCK * sizeof *ard); 75 if (!ard) 76 goto out; 77 78 ard_count = 0; 79 ard_space = RANGE_ALLOC_BLOCK; 80 81 /* First try INT 15h AX=E820h */ 82 memset(&ireg, 0, sizeof ireg); 83 ireg.eax.l = 0xe820; 84 ireg.edx.l = 0x534d4150; 85 /* ireg.ebx.l = 0; */ 86 ireg.ecx.l = sizeof(*e820buf); 87 ireg.es = SEG(e820buf); 88 ireg.edi.w[0] = OFFS(e820buf); 89 memset(e820buf, 0, sizeof *e820buf); 90 91 do { 92 __intcall(0x15, &ireg, &oreg); 93 94 if ((oreg.eflags.l & EFLAGS_CF) || 95 (oreg.eax.l != 0x534d4150) || (oreg.ecx.l < 20)) 96 break; 97 98 if (ard_count >= ard_space) { 99 ard_space += RANGE_ALLOC_BLOCK; 100 *ardp = ard = realloc(ard, ard_space * sizeof *ard); 101 if (!ard) { 102 rv = ard_count; 103 goto out; 104 } 105 } 106 107 ard[ard_count].size = 20; 108 ard[ard_count].BaseAddr = e820buf->start; 109 ard[ard_count].Length = e820buf->len; 110 ard[ard_count].Type = e820buf->type; 111 ard_count++; 112 113 ireg.ebx.l = oreg.ebx.l; 114 } while (oreg.ebx.l); 115 116 if (ard_count) { 117 rv = ard_count; 118 goto out; 119 }; 120 121 ard[0].size = 20; 122 ard[0].BaseAddr = 0; 123 ard[0].Length = *dosmem << 10; 124 ard[0].Type = 1; 125 126 /* Next try INT 15h AX=E801h */ 127 memset(&ireg, 0, sizeof ireg); 128 ireg.eax.w[0] = 0xe801; 129 __intcall(0x15, &ireg, &oreg); 130 131 if (!(oreg.eflags.l & EFLAGS_CF) && oreg.ecx.w[0]) { 132 ard[1].size = 20; 133 ard[1].BaseAddr = 1 << 20; 134 ard[1].Length = oreg.ecx.w[0] << 10; 135 ard[1].Type = 1; 136 137 if (oreg.edx.w[0]) { 138 ard[2].size = 20; 139 ard[2].BaseAddr = 16 << 20; 140 ard[2].Length = oreg.edx.w[0] << 16; 141 ard[2].Type = 1; 142 rv = 3; 143 } else { 144 rv = 2; 145 } 146 147 goto out; 148 } 149 150 /* Finally try INT 15h AH=88h */ 151 memset(&ireg, 0, sizeof ireg); 152 ireg.eax.w[0] = 0x8800; 153 __intcall(0x15, &ireg, &oreg); 154 if (!(oreg.eflags.l & EFLAGS_CF) && oreg.eax.w[0]) { 155 ard[1].size = 20; 156 ard[1].BaseAddr = 1 << 20; 157 ard[1].Length = oreg.ecx.w[0] << 10; 158 ard[1].Type = 1; 159 rv = 2; 160 goto out; 161 } 162 163 rv = 1; /* ... problematic ... */ 164 out: 165 lfree(e820buf); 166 return rv; 167 } 168 169 void mboot_make_memmap(void) 170 { 171 int i, nmap; 172 struct AddrRangeDesc *ard; 173 uint32_t lowmem, highmem; 174 uint32_t highrsvd; 175 176 /* Always report DOS memory as "lowmem", this may be overly conservative 177 (e.g. if we're dropping PXE), but it should be *safe*... */ 178 179 nmap = mboot_scan_memory(&ard, &lowmem); 180 181 highmem = 0x100000; 182 highrsvd = 0xfff00000; 183 184 again: 185 for (i = 0; i < nmap; i++) { 186 uint64_t start, end; 187 188 start = ard[i].BaseAddr; 189 end = start + ard[i].Length; 190 191 if (end < start) 192 end = ~0ULL; 193 194 if (start & 0xffffffff00000000ULL) 195 continue; /* Not interested in 64-bit memory */ 196 197 if (start < highmem) 198 start = highmem; 199 200 if (end <= start) 201 continue; 202 203 if (ard[i].Type == 1 && start == highmem) { 204 highmem = end; 205 goto again; 206 } else if (ard[i].Type != 1 && start < highrsvd) 207 highrsvd = start; 208 } 209 210 if (highmem > highrsvd) 211 highmem = highrsvd; 212 213 mbinfo.mem_lower = lowmem >> 10; 214 mbinfo.mem_upper = (highmem - 0x100000) >> 10; 215 mbinfo.flags |= MB_INFO_MEMORY; 216 217 /* The spec says this address should be +4, but Grub disagrees */ 218 mbinfo.mmap_addr = map_data(ard, nmap * sizeof *ard, 4, false); 219 if (mbinfo.mmap_addr) { 220 mbinfo.mmap_length = nmap * sizeof *ard; 221 mbinfo.flags |= MB_INFO_MEM_MAP; 222 } 223 } 224
