1 #include <linux/gfp.h> 2 #include <linux/initrd.h> 3 #include <linux/ioport.h> 4 #include <linux/swap.h> 5 #include <linux/memblock.h> 6 #include <linux/bootmem.h> /* for max_low_pfn */ 7 8 #include <asm/set_memory.h> 9 #include <asm/e820/api.h> 10 #include <asm/init.h> 11 #include <asm/page.h> 12 #include <asm/page_types.h> 13 #include <asm/sections.h> 14 #include <asm/setup.h> 15 #include <asm/tlbflush.h> 16 #include <asm/tlb.h> 17 #include <asm/proto.h> 18 #include <asm/dma.h> /* for MAX_DMA_PFN */ 19 #include <asm/microcode.h> 20 #include <asm/kaslr.h> 21 22 /* 23 * We need to define the tracepoints somewhere, and tlb.c 24 * is only compied when SMP=y. 25 */ 26 #define CREATE_TRACE_POINTS 27 #include <trace/events/tlb.h> 28 29 #include "mm_internal.h" 30 31 /* 32 * Tables translating between page_cache_type_t and pte encoding. 33 * 34 * The default values are defined statically as minimal supported mode; 35 * WC and WT fall back to UC-. pat_init() updates these values to support 36 * more cache modes, WC and WT, when it is safe to do so. See pat_init() 37 * for the details. Note, __early_ioremap() used during early boot-time 38 * takes pgprot_t (pte encoding) and does not use these tables. 39 * 40 * Index into __cachemode2pte_tbl[] is the cachemode. 41 * 42 * Index into __pte2cachemode_tbl[] are the caching attribute bits of the pte 43 * (_PAGE_PWT, _PAGE_PCD, _PAGE_PAT) at index bit positions 0, 1, 2. 44 */ 45 uint16_t __cachemode2pte_tbl[_PAGE_CACHE_MODE_NUM] = { 46 [_PAGE_CACHE_MODE_WB ] = 0 | 0 , 47 [_PAGE_CACHE_MODE_WC ] = 0 | _PAGE_PCD, 48 [_PAGE_CACHE_MODE_UC_MINUS] = 0 | _PAGE_PCD, 49 [_PAGE_CACHE_MODE_UC ] = _PAGE_PWT | _PAGE_PCD, 50 [_PAGE_CACHE_MODE_WT ] = 0 | _PAGE_PCD, 51 [_PAGE_CACHE_MODE_WP ] = 0 | _PAGE_PCD, 52 }; 53 EXPORT_SYMBOL(__cachemode2pte_tbl); 54 55 uint8_t __pte2cachemode_tbl[8] = { 56 [__pte2cm_idx( 0 | 0 | 0 )] = _PAGE_CACHE_MODE_WB, 57 [__pte2cm_idx(_PAGE_PWT | 0 | 0 )] = _PAGE_CACHE_MODE_UC_MINUS, 58 [__pte2cm_idx( 0 | _PAGE_PCD | 0 )] = _PAGE_CACHE_MODE_UC_MINUS, 59 [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | 0 )] = _PAGE_CACHE_MODE_UC, 60 [__pte2cm_idx( 0 | 0 | _PAGE_PAT)] = _PAGE_CACHE_MODE_WB, 61 [__pte2cm_idx(_PAGE_PWT | 0 | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS, 62 [__pte2cm_idx(0 | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC_MINUS, 63 [__pte2cm_idx(_PAGE_PWT | _PAGE_PCD | _PAGE_PAT)] = _PAGE_CACHE_MODE_UC, 64 }; 65 EXPORT_SYMBOL(__pte2cachemode_tbl); 66 67 static unsigned long __initdata pgt_buf_start; 68 static unsigned long __initdata pgt_buf_end; 69 static unsigned long __initdata pgt_buf_top; 70 71 static unsigned long min_pfn_mapped; 72 73 static bool __initdata can_use_brk_pgt = true; 74 75 /* 76 * Pages returned are already directly mapped. 77 * 78 * Changing that is likely to break Xen, see commit: 79 * 80 * 279b706 x86,xen: introduce x86_init.mapping.pagetable_reserve 81 * 82 * for detailed information. 83 */ 84 __ref void *alloc_low_pages(unsigned int num) 85 { 86 unsigned long pfn; 87 int i; 88 89 if (after_bootmem) { 90 unsigned int order; 91 92 order = get_order((unsigned long)num << PAGE_SHIFT); 93 return (void *)__get_free_pages(GFP_ATOMIC | __GFP_NOTRACK | 94 __GFP_ZERO, order); 95 } 96 97 if ((pgt_buf_end + num) > pgt_buf_top || !can_use_brk_pgt) { 98 unsigned long ret; 99 if (min_pfn_mapped >= max_pfn_mapped) 100 panic("alloc_low_pages: ran out of memory"); 101 ret = memblock_find_in_range(min_pfn_mapped << PAGE_SHIFT, 102 max_pfn_mapped << PAGE_SHIFT, 103 PAGE_SIZE * num , PAGE_SIZE); 104 if (!ret) 105 panic("alloc_low_pages: can not alloc memory"); 106 memblock_reserve(ret, PAGE_SIZE * num); 107 pfn = ret >> PAGE_SHIFT; 108 } else { 109 pfn = pgt_buf_end; 110 pgt_buf_end += num; 111 printk(KERN_DEBUG "BRK [%#010lx, %#010lx] PGTABLE\n", 112 pfn << PAGE_SHIFT, (pgt_buf_end << PAGE_SHIFT) - 1); 113 } 114 115 for (i = 0; i < num; i++) { 116 void *adr; 117 118 adr = __va((pfn + i) << PAGE_SHIFT); 119 clear_page(adr); 120 } 121 122 return __va(pfn << PAGE_SHIFT); 123 } 124 125 /* 126 * By default need 3 4k for initial PMD_SIZE, 3 4k for 0-ISA_END_ADDRESS. 127 * With KASLR memory randomization, depending on the machine e820 memory 128 * and the PUD alignment. We may need twice more pages when KASLR memory 129 * randomization is enabled. 130 */ 131 #ifndef CONFIG_RANDOMIZE_MEMORY 132 #define INIT_PGD_PAGE_COUNT 6 133 #else 134 #define INIT_PGD_PAGE_COUNT 12 135 #endif 136 #define INIT_PGT_BUF_SIZE (INIT_PGD_PAGE_COUNT * PAGE_SIZE) 137 RESERVE_BRK(early_pgt_alloc, INIT_PGT_BUF_SIZE); 138 void __init early_alloc_pgt_buf(void) 139 { 140 unsigned long tables = INIT_PGT_BUF_SIZE; 141 phys_addr_t base; 142 143 base = __pa(extend_brk(tables, PAGE_SIZE)); 144 145 pgt_buf_start = base >> PAGE_SHIFT; 146 pgt_buf_end = pgt_buf_start; 147 pgt_buf_top = pgt_buf_start + (tables >> PAGE_SHIFT); 148 } 149 150 int after_bootmem; 151 152 early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES); 153 154 struct map_range { 155 unsigned long start; 156 unsigned long end; 157 unsigned page_size_mask; 158 }; 159 160 static int page_size_mask; 161 162 static void __init probe_page_size_mask(void) 163 { 164 /* 165 * For CONFIG_KMEMCHECK or pagealloc debugging, identity mapping will 166 * use small pages. 167 * This will simplify cpa(), which otherwise needs to support splitting 168 * large pages into small in interrupt context, etc. 169 */ 170 if (boot_cpu_has(X86_FEATURE_PSE) && !debug_pagealloc_enabled() && !IS_ENABLED(CONFIG_KMEMCHECK)) 171 page_size_mask |= 1 << PG_LEVEL_2M; 172 else 173 direct_gbpages = 0; 174 175 /* Enable PSE if available */ 176 if (boot_cpu_has(X86_FEATURE_PSE)) 177 cr4_set_bits_and_update_boot(X86_CR4_PSE); 178 179 /* Enable PGE if available */ 180 if (boot_cpu_has(X86_FEATURE_PGE)) { 181 cr4_set_bits_and_update_boot(X86_CR4_PGE); 182 __supported_pte_mask |= _PAGE_GLOBAL; 183 } else 184 __supported_pte_mask &= ~_PAGE_GLOBAL; 185 186 /* Enable 1 GB linear kernel mappings if available: */ 187 if (direct_gbpages && boot_cpu_has(X86_FEATURE_GBPAGES)) { 188 printk(KERN_INFO "Using GB pages for direct mapping\n"); 189 page_size_mask |= 1 << PG_LEVEL_1G; 190 } else { 191 direct_gbpages = 0; 192 } 193 } 194 195 #ifdef CONFIG_X86_32 196 #define NR_RANGE_MR 3 197 #else /* CONFIG_X86_64 */ 198 #define NR_RANGE_MR 5 199 #endif 200 201 static int __meminit save_mr(struct map_range *mr, int nr_range, 202 unsigned long start_pfn, unsigned long end_pfn, 203 unsigned long page_size_mask) 204 { 205 if (start_pfn < end_pfn) { 206 if (nr_range >= NR_RANGE_MR) 207 panic("run out of range for init_memory_mapping\n"); 208 mr[nr_range].start = start_pfn<<PAGE_SHIFT; 209 mr[nr_range].end = end_pfn<<PAGE_SHIFT; 210 mr[nr_range].page_size_mask = page_size_mask; 211 nr_range++; 212 } 213 214 return nr_range; 215 } 216 217 /* 218 * adjust the page_size_mask for small range to go with 219 * big page size instead small one if nearby are ram too. 220 */ 221 static void __ref adjust_range_page_size_mask(struct map_range *mr, 222 int nr_range) 223 { 224 int i; 225 226 for (i = 0; i < nr_range; i++) { 227 if ((page_size_mask & (1<<PG_LEVEL_2M)) && 228 !(mr[i].page_size_mask & (1<<PG_LEVEL_2M))) { 229 unsigned long start = round_down(mr[i].start, PMD_SIZE); 230 unsigned long end = round_up(mr[i].end, PMD_SIZE); 231 232 #ifdef CONFIG_X86_32 233 if ((end >> PAGE_SHIFT) > max_low_pfn) 234 continue; 235 #endif 236 237 if (memblock_is_region_memory(start, end - start)) 238 mr[i].page_size_mask |= 1<<PG_LEVEL_2M; 239 } 240 if ((page_size_mask & (1<<PG_LEVEL_1G)) && 241 !(mr[i].page_size_mask & (1<<PG_LEVEL_1G))) { 242 unsigned long start = round_down(mr[i].start, PUD_SIZE); 243 unsigned long end = round_up(mr[i].end, PUD_SIZE); 244 245 if (memblock_is_region_memory(start, end - start)) 246 mr[i].page_size_mask |= 1<<PG_LEVEL_1G; 247 } 248 } 249 } 250 251 static const char *page_size_string(struct map_range *mr) 252 { 253 static const char str_1g[] = "1G"; 254 static const char str_2m[] = "2M"; 255 static const char str_4m[] = "4M"; 256 static const char str_4k[] = "4k"; 257 258 if (mr->page_size_mask & (1<<PG_LEVEL_1G)) 259 return str_1g; 260 /* 261 * 32-bit without PAE has a 4M large page size. 262 * PG_LEVEL_2M is misnamed, but we can at least 263 * print out the right size in the string. 264 */ 265 if (IS_ENABLED(CONFIG_X86_32) && 266 !IS_ENABLED(CONFIG_X86_PAE) && 267 mr->page_size_mask & (1<<PG_LEVEL_2M)) 268 return str_4m; 269 270 if (mr->page_size_mask & (1<<PG_LEVEL_2M)) 271 return str_2m; 272 273 return str_4k; 274 } 275 276 static int __meminit split_mem_range(struct map_range *mr, int nr_range, 277 unsigned long start, 278 unsigned long end) 279 { 280 unsigned long start_pfn, end_pfn, limit_pfn; 281 unsigned long pfn; 282 int i; 283 284 limit_pfn = PFN_DOWN(end); 285 286 /* head if not big page alignment ? */ 287 pfn = start_pfn = PFN_DOWN(start); 288 #ifdef CONFIG_X86_32 289 /* 290 * Don't use a large page for the first 2/4MB of memory 291 * because there are often fixed size MTRRs in there 292 * and overlapping MTRRs into large pages can cause 293 * slowdowns. 294 */ 295 if (pfn == 0) 296 end_pfn = PFN_DOWN(PMD_SIZE); 297 else 298 end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE)); 299 #else /* CONFIG_X86_64 */ 300 end_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE)); 301 #endif 302 if (end_pfn > limit_pfn) 303 end_pfn = limit_pfn; 304 if (start_pfn < end_pfn) { 305 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0); 306 pfn = end_pfn; 307 } 308 309 /* big page (2M) range */ 310 start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE)); 311 #ifdef CONFIG_X86_32 312 end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE)); 313 #else /* CONFIG_X86_64 */ 314 end_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE)); 315 if (end_pfn > round_down(limit_pfn, PFN_DOWN(PMD_SIZE))) 316 end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE)); 317 #endif 318 319 if (start_pfn < end_pfn) { 320 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 321 page_size_mask & (1<<PG_LEVEL_2M)); 322 pfn = end_pfn; 323 } 324 325 #ifdef CONFIG_X86_64 326 /* big page (1G) range */ 327 start_pfn = round_up(pfn, PFN_DOWN(PUD_SIZE)); 328 end_pfn = round_down(limit_pfn, PFN_DOWN(PUD_SIZE)); 329 if (start_pfn < end_pfn) { 330 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 331 page_size_mask & 332 ((1<<PG_LEVEL_2M)|(1<<PG_LEVEL_1G))); 333 pfn = end_pfn; 334 } 335 336 /* tail is not big page (1G) alignment */ 337 start_pfn = round_up(pfn, PFN_DOWN(PMD_SIZE)); 338 end_pfn = round_down(limit_pfn, PFN_DOWN(PMD_SIZE)); 339 if (start_pfn < end_pfn) { 340 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 341 page_size_mask & (1<<PG_LEVEL_2M)); 342 pfn = end_pfn; 343 } 344 #endif 345 346 /* tail is not big page (2M) alignment */ 347 start_pfn = pfn; 348 end_pfn = limit_pfn; 349 nr_range = save_mr(mr, nr_range, start_pfn, end_pfn, 0); 350 351 if (!after_bootmem) 352 adjust_range_page_size_mask(mr, nr_range); 353 354 /* try to merge same page size and continuous */ 355 for (i = 0; nr_range > 1 && i < nr_range - 1; i++) { 356 unsigned long old_start; 357 if (mr[i].end != mr[i+1].start || 358 mr[i].page_size_mask != mr[i+1].page_size_mask) 359 continue; 360 /* move it */ 361 old_start = mr[i].start; 362 memmove(&mr[i], &mr[i+1], 363 (nr_range - 1 - i) * sizeof(struct map_range)); 364 mr[i--].start = old_start; 365 nr_range--; 366 } 367 368 for (i = 0; i < nr_range; i++) 369 pr_debug(" [mem %#010lx-%#010lx] page %s\n", 370 mr[i].start, mr[i].end - 1, 371 page_size_string(&mr[i])); 372 373 return nr_range; 374 } 375 376 struct range pfn_mapped[E820_MAX_ENTRIES]; 377 int nr_pfn_mapped; 378 379 static void add_pfn_range_mapped(unsigned long start_pfn, unsigned long end_pfn) 380 { 381 nr_pfn_mapped = add_range_with_merge(pfn_mapped, E820_MAX_ENTRIES, 382 nr_pfn_mapped, start_pfn, end_pfn); 383 nr_pfn_mapped = clean_sort_range(pfn_mapped, E820_MAX_ENTRIES); 384 385 max_pfn_mapped = max(max_pfn_mapped, end_pfn); 386 387 if (start_pfn < (1UL<<(32-PAGE_SHIFT))) 388 max_low_pfn_mapped = max(max_low_pfn_mapped, 389 min(end_pfn, 1UL<<(32-PAGE_SHIFT))); 390 } 391 392 bool pfn_range_is_mapped(unsigned long start_pfn, unsigned long end_pfn) 393 { 394 int i; 395 396 for (i = 0; i < nr_pfn_mapped; i++) 397 if ((start_pfn >= pfn_mapped[i].start) && 398 (end_pfn <= pfn_mapped[i].end)) 399 return true; 400 401 return false; 402 } 403 404 /* 405 * Setup the direct mapping of the physical memory at PAGE_OFFSET. 406 * This runs before bootmem is initialized and gets pages directly from 407 * the physical memory. To access them they are temporarily mapped. 408 */ 409 unsigned long __ref init_memory_mapping(unsigned long start, 410 unsigned long end) 411 { 412 struct map_range mr[NR_RANGE_MR]; 413 unsigned long ret = 0; 414 int nr_range, i; 415 416 pr_debug("init_memory_mapping: [mem %#010lx-%#010lx]\n", 417 start, end - 1); 418 419 memset(mr, 0, sizeof(mr)); 420 nr_range = split_mem_range(mr, 0, start, end); 421 422 for (i = 0; i < nr_range; i++) 423 ret = kernel_physical_mapping_init(mr[i].start, mr[i].end, 424 mr[i].page_size_mask); 425 426 add_pfn_range_mapped(start >> PAGE_SHIFT, ret >> PAGE_SHIFT); 427 428 return ret >> PAGE_SHIFT; 429 } 430 431 /* 432 * We need to iterate through the E820 memory map and create direct mappings 433 * for only E820_TYPE_RAM and E820_KERN_RESERVED regions. We cannot simply 434 * create direct mappings for all pfns from [0 to max_low_pfn) and 435 * [4GB to max_pfn) because of possible memory holes in high addresses 436 * that cannot be marked as UC by fixed/variable range MTRRs. 437 * Depending on the alignment of E820 ranges, this may possibly result 438 * in using smaller size (i.e. 4K instead of 2M or 1G) page tables. 439 * 440 * init_mem_mapping() calls init_range_memory_mapping() with big range. 441 * That range would have hole in the middle or ends, and only ram parts 442 * will be mapped in init_range_memory_mapping(). 443 */ 444 static unsigned long __init init_range_memory_mapping( 445 unsigned long r_start, 446 unsigned long r_end) 447 { 448 unsigned long start_pfn, end_pfn; 449 unsigned long mapped_ram_size = 0; 450 int i; 451 452 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) { 453 u64 start = clamp_val(PFN_PHYS(start_pfn), r_start, r_end); 454 u64 end = clamp_val(PFN_PHYS(end_pfn), r_start, r_end); 455 if (start >= end) 456 continue; 457 458 /* 459 * if it is overlapping with brk pgt, we need to 460 * alloc pgt buf from memblock instead. 461 */ 462 can_use_brk_pgt = max(start, (u64)pgt_buf_end<<PAGE_SHIFT) >= 463 min(end, (u64)pgt_buf_top<<PAGE_SHIFT); 464 init_memory_mapping(start, end); 465 mapped_ram_size += end - start; 466 can_use_brk_pgt = true; 467 } 468 469 return mapped_ram_size; 470 } 471 472 static unsigned long __init get_new_step_size(unsigned long step_size) 473 { 474 /* 475 * Initial mapped size is PMD_SIZE (2M). 476 * We can not set step_size to be PUD_SIZE (1G) yet. 477 * In worse case, when we cross the 1G boundary, and 478 * PG_LEVEL_2M is not set, we will need 1+1+512 pages (2M + 8k) 479 * to map 1G range with PTE. Hence we use one less than the 480 * difference of page table level shifts. 481 * 482 * Don't need to worry about overflow in the top-down case, on 32bit, 483 * when step_size is 0, round_down() returns 0 for start, and that 484 * turns it into 0x100000000ULL. 485 * In the bottom-up case, round_up(x, 0) returns 0 though too, which 486 * needs to be taken into consideration by the code below. 487 */ 488 return step_size << (PMD_SHIFT - PAGE_SHIFT - 1); 489 } 490 491 /** 492 * memory_map_top_down - Map [map_start, map_end) top down 493 * @map_start: start address of the target memory range 494 * @map_end: end address of the target memory range 495 * 496 * This function will setup direct mapping for memory range 497 * [map_start, map_end) in top-down. That said, the page tables 498 * will be allocated at the end of the memory, and we map the 499 * memory in top-down. 500 */ 501 static void __init memory_map_top_down(unsigned long map_start, 502 unsigned long map_end) 503 { 504 unsigned long real_end, start, last_start; 505 unsigned long step_size; 506 unsigned long addr; 507 unsigned long mapped_ram_size = 0; 508 509 /* xen has big range in reserved near end of ram, skip it at first.*/ 510 addr = memblock_find_in_range(map_start, map_end, PMD_SIZE, PMD_SIZE); 511 real_end = addr + PMD_SIZE; 512 513 /* step_size need to be small so pgt_buf from BRK could cover it */ 514 step_size = PMD_SIZE; 515 max_pfn_mapped = 0; /* will get exact value next */ 516 min_pfn_mapped = real_end >> PAGE_SHIFT; 517 last_start = start = real_end; 518 519 /* 520 * We start from the top (end of memory) and go to the bottom. 521 * The memblock_find_in_range() gets us a block of RAM from the 522 * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages 523 * for page table. 524 */ 525 while (last_start > map_start) { 526 if (last_start > step_size) { 527 start = round_down(last_start - 1, step_size); 528 if (start < map_start) 529 start = map_start; 530 } else 531 start = map_start; 532 mapped_ram_size += init_range_memory_mapping(start, 533 last_start); 534 last_start = start; 535 min_pfn_mapped = last_start >> PAGE_SHIFT; 536 if (mapped_ram_size >= step_size) 537 step_size = get_new_step_size(step_size); 538 } 539 540 if (real_end < map_end) 541 init_range_memory_mapping(real_end, map_end); 542 } 543 544 /** 545 * memory_map_bottom_up - Map [map_start, map_end) bottom up 546 * @map_start: start address of the target memory range 547 * @map_end: end address of the target memory range 548 * 549 * This function will setup direct mapping for memory range 550 * [map_start, map_end) in bottom-up. Since we have limited the 551 * bottom-up allocation above the kernel, the page tables will 552 * be allocated just above the kernel and we map the memory 553 * in [map_start, map_end) in bottom-up. 554 */ 555 static void __init memory_map_bottom_up(unsigned long map_start, 556 unsigned long map_end) 557 { 558 unsigned long next, start; 559 unsigned long mapped_ram_size = 0; 560 /* step_size need to be small so pgt_buf from BRK could cover it */ 561 unsigned long step_size = PMD_SIZE; 562 563 start = map_start; 564 min_pfn_mapped = start >> PAGE_SHIFT; 565 566 /* 567 * We start from the bottom (@map_start) and go to the top (@map_end). 568 * The memblock_find_in_range() gets us a block of RAM from the 569 * end of RAM in [min_pfn_mapped, max_pfn_mapped) used as new pages 570 * for page table. 571 */ 572 while (start < map_end) { 573 if (step_size && map_end - start > step_size) { 574 next = round_up(start + 1, step_size); 575 if (next > map_end) 576 next = map_end; 577 } else { 578 next = map_end; 579 } 580 581 mapped_ram_size += init_range_memory_mapping(start, next); 582 start = next; 583 584 if (mapped_ram_size >= step_size) 585 step_size = get_new_step_size(step_size); 586 } 587 } 588 589 void __init init_mem_mapping(void) 590 { 591 unsigned long end; 592 593 probe_page_size_mask(); 594 595 #ifdef CONFIG_X86_64 596 end = max_pfn << PAGE_SHIFT; 597 #else 598 end = max_low_pfn << PAGE_SHIFT; 599 #endif 600 601 /* the ISA range is always mapped regardless of memory holes */ 602 init_memory_mapping(0, ISA_END_ADDRESS); 603 604 /* Init the trampoline, possibly with KASLR memory offset */ 605 init_trampoline(); 606 607 /* 608 * If the allocation is in bottom-up direction, we setup direct mapping 609 * in bottom-up, otherwise we setup direct mapping in top-down. 610 */ 611 if (memblock_bottom_up()) { 612 unsigned long kernel_end = __pa_symbol(_end); 613 614 /* 615 * we need two separate calls here. This is because we want to 616 * allocate page tables above the kernel. So we first map 617 * [kernel_end, end) to make memory above the kernel be mapped 618 * as soon as possible. And then use page tables allocated above 619 * the kernel to map [ISA_END_ADDRESS, kernel_end). 620 */ 621 memory_map_bottom_up(kernel_end, end); 622 memory_map_bottom_up(ISA_END_ADDRESS, kernel_end); 623 } else { 624 memory_map_top_down(ISA_END_ADDRESS, end); 625 } 626 627 #ifdef CONFIG_X86_64 628 if (max_pfn > max_low_pfn) { 629 /* can we preseve max_low_pfn ?*/ 630 max_low_pfn = max_pfn; 631 } 632 #else 633 early_ioremap_page_table_range_init(); 634 #endif 635 636 load_cr3(swapper_pg_dir); 637 __flush_tlb_all(); 638 639 early_memtest(0, max_pfn_mapped << PAGE_SHIFT); 640 } 641 642 /* 643 * devmem_is_allowed() checks to see if /dev/mem access to a certain address 644 * is valid. The argument is a physical page number. 645 * 646 * On x86, access has to be given to the first megabyte of RAM because that 647 * area traditionally contains BIOS code and data regions used by X, dosemu, 648 * and similar apps. Since they map the entire memory range, the whole range 649 * must be allowed (for mapping), but any areas that would otherwise be 650 * disallowed are flagged as being "zero filled" instead of rejected. 651 * Access has to be given to non-kernel-ram areas as well, these contain the 652 * PCI mmio resources as well as potential bios/acpi data regions. 653 */ 654 int devmem_is_allowed(unsigned long pagenr) 655 { 656 if (page_is_ram(pagenr)) { 657 /* 658 * For disallowed memory regions in the low 1MB range, 659 * request that the page be shown as all zeros. 660 */ 661 if (pagenr < 256) 662 return 2; 663 664 return 0; 665 } 666 667 /* 668 * This must follow RAM test, since System RAM is considered a 669 * restricted resource under CONFIG_STRICT_IOMEM. 670 */ 671 if (iomem_is_exclusive(pagenr << PAGE_SHIFT)) { 672 /* Low 1MB bypasses iomem restrictions. */ 673 if (pagenr < 256) 674 return 1; 675 676 return 0; 677 } 678 679 return 1; 680 } 681 682 void free_init_pages(char *what, unsigned long begin, unsigned long end) 683 { 684 unsigned long begin_aligned, end_aligned; 685 686 /* Make sure boundaries are page aligned */ 687 begin_aligned = PAGE_ALIGN(begin); 688 end_aligned = end & PAGE_MASK; 689 690 if (WARN_ON(begin_aligned != begin || end_aligned != end)) { 691 begin = begin_aligned; 692 end = end_aligned; 693 } 694 695 if (begin >= end) 696 return; 697 698 /* 699 * If debugging page accesses then do not free this memory but 700 * mark them not present - any buggy init-section access will 701 * create a kernel page fault: 702 */ 703 if (debug_pagealloc_enabled()) { 704 pr_info("debug: unmapping init [mem %#010lx-%#010lx]\n", 705 begin, end - 1); 706 set_memory_np(begin, (end - begin) >> PAGE_SHIFT); 707 } else { 708 /* 709 * We just marked the kernel text read only above, now that 710 * we are going to free part of that, we need to make that 711 * writeable and non-executable first. 712 */ 713 set_memory_nx(begin, (end - begin) >> PAGE_SHIFT); 714 set_memory_rw(begin, (end - begin) >> PAGE_SHIFT); 715 716 free_reserved_area((void *)begin, (void *)end, 717 POISON_FREE_INITMEM, what); 718 } 719 } 720 721 void __ref free_initmem(void) 722 { 723 e820__reallocate_tables(); 724 725 free_init_pages("unused kernel", 726 (unsigned long)(&__init_begin), 727 (unsigned long)(&__init_end)); 728 } 729 730 #ifdef CONFIG_BLK_DEV_INITRD 731 void __init free_initrd_mem(unsigned long start, unsigned long end) 732 { 733 /* 734 * end could be not aligned, and We can not align that, 735 * decompresser could be confused by aligned initrd_end 736 * We already reserve the end partial page before in 737 * - i386_start_kernel() 738 * - x86_64_start_kernel() 739 * - relocate_initrd() 740 * So here We can do PAGE_ALIGN() safely to get partial page to be freed 741 */ 742 free_init_pages("initrd", start, PAGE_ALIGN(end)); 743 } 744 #endif 745 746 /* 747 * Calculate the precise size of the DMA zone (first 16 MB of RAM), 748 * and pass it to the MM layer - to help it set zone watermarks more 749 * accurately. 750 * 751 * Done on 64-bit systems only for the time being, although 32-bit systems 752 * might benefit from this as well. 753 */ 754 void __init memblock_find_dma_reserve(void) 755 { 756 #ifdef CONFIG_X86_64 757 u64 nr_pages = 0, nr_free_pages = 0; 758 unsigned long start_pfn, end_pfn; 759 phys_addr_t start_addr, end_addr; 760 int i; 761 u64 u; 762 763 /* 764 * Iterate over all memory ranges (free and reserved ones alike), 765 * to calculate the total number of pages in the first 16 MB of RAM: 766 */ 767 nr_pages = 0; 768 for_each_mem_pfn_range(i, MAX_NUMNODES, &start_pfn, &end_pfn, NULL) { 769 start_pfn = min(start_pfn, MAX_DMA_PFN); 770 end_pfn = min(end_pfn, MAX_DMA_PFN); 771 772 nr_pages += end_pfn - start_pfn; 773 } 774 775 /* 776 * Iterate over free memory ranges to calculate the number of free 777 * pages in the DMA zone, while not counting potential partial 778 * pages at the beginning or the end of the range: 779 */ 780 nr_free_pages = 0; 781 for_each_free_mem_range(u, NUMA_NO_NODE, MEMBLOCK_NONE, &start_addr, &end_addr, NULL) { 782 start_pfn = min_t(unsigned long, PFN_UP(start_addr), MAX_DMA_PFN); 783 end_pfn = min_t(unsigned long, PFN_DOWN(end_addr), MAX_DMA_PFN); 784 785 if (start_pfn < end_pfn) 786 nr_free_pages += end_pfn - start_pfn; 787 } 788 789 set_dma_reserve(nr_pages - nr_free_pages); 790 #endif 791 } 792 793 void __init zone_sizes_init(void) 794 { 795 unsigned long max_zone_pfns[MAX_NR_ZONES]; 796 797 memset(max_zone_pfns, 0, sizeof(max_zone_pfns)); 798 799 #ifdef CONFIG_ZONE_DMA 800 max_zone_pfns[ZONE_DMA] = min(MAX_DMA_PFN, max_low_pfn); 801 #endif 802 #ifdef CONFIG_ZONE_DMA32 803 max_zone_pfns[ZONE_DMA32] = min(MAX_DMA32_PFN, max_low_pfn); 804 #endif 805 max_zone_pfns[ZONE_NORMAL] = max_low_pfn; 806 #ifdef CONFIG_HIGHMEM 807 max_zone_pfns[ZONE_HIGHMEM] = max_pfn; 808 #endif 809 810 free_area_init_nodes(max_zone_pfns); 811 } 812 813 DEFINE_PER_CPU_SHARED_ALIGNED(struct tlb_state, cpu_tlbstate) = { 814 .loaded_mm = &init_mm, 815 .state = 0, 816 .cr4 = ~0UL, /* fail hard if we screw up cr4 shadow initialization */ 817 }; 818 EXPORT_SYMBOL_GPL(cpu_tlbstate); 819 820 void update_cache_mode_entry(unsigned entry, enum page_cache_mode cache) 821 { 822 /* entry 0 MUST be WB (hardwired to speed up translations) */ 823 BUG_ON(!entry && cache != _PAGE_CACHE_MODE_WB); 824 825 __cachemode2pte_tbl[cache] = __cm_idx2pte(entry); 826 __pte2cachemode_tbl[entry] = cache; 827 } 828