1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * linux/kernel/power/snapshot.c 4 * 5 * This file provides system snapshot/restore functionality for swsusp. 6 * 7 * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz> 8 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl> 9 */ 10 11 #define pr_fmt(fmt) "PM: hibernation: " fmt 12 13 #include <linux/version.h> 14 #include <linux/module.h> 15 #include <linux/mm.h> 16 #include <linux/suspend.h> 17 #include <linux/delay.h> 18 #include <linux/bitops.h> 19 #include <linux/spinlock.h> 20 #include <linux/kernel.h> 21 #include <linux/pm.h> 22 #include <linux/device.h> 23 #include <linux/init.h> 24 #include <linux/memblock.h> 25 #include <linux/nmi.h> 26 #include <linux/syscalls.h> 27 #include <linux/console.h> 28 #include <linux/highmem.h> 29 #include <linux/list.h> 30 #include <linux/slab.h> 31 #include <linux/compiler.h> 32 #include <linux/ktime.h> 33 #include <linux/set_memory.h> 34 35 #include <linux/uaccess.h> 36 #include <asm/mmu_context.h> 37 #include <asm/tlbflush.h> 38 #include <asm/io.h> 39 40 #include "power.h" 41 42 #if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_ARCH_HAS_SET_MEMORY) 43 static bool hibernate_restore_protection; 44 static bool hibernate_restore_protection_active; 45 46 void enable_restore_image_protection(void) 47 { 48 hibernate_restore_protection = true; 49 } 50 51 static inline void hibernate_restore_protection_begin(void) 52 { 53 hibernate_restore_protection_active = hibernate_restore_protection; 54 } 55 56 static inline void hibernate_restore_protection_end(void) 57 { 58 hibernate_restore_protection_active = false; 59 } 60 61 static inline void hibernate_restore_protect_page(void *page_address) 62 { 63 if (hibernate_restore_protection_active) 64 set_memory_ro((unsigned long)page_address, 1); 65 } 66 67 static inline void hibernate_restore_unprotect_page(void *page_address) 68 { 69 if (hibernate_restore_protection_active) 70 set_memory_rw((unsigned long)page_address, 1); 71 } 72 #else 73 static inline void hibernate_restore_protection_begin(void) {} 74 static inline void hibernate_restore_protection_end(void) {} 75 static inline void hibernate_restore_protect_page(void *page_address) {} 76 static inline void hibernate_restore_unprotect_page(void *page_address) {} 77 #endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */ 78 79 80 /* 81 * The calls to set_direct_map_*() should not fail because remapping a page 82 * here means that we only update protection bits in an existing PTE. 83 * It is still worth to have a warning here if something changes and this 84 * will no longer be the case. 85 */ 86 static inline void hibernate_map_page(struct page *page) 87 { 88 if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { 89 int ret = set_direct_map_default_noflush(page); 90 91 if (ret) 92 pr_warn_once("Failed to remap page\n"); 93 } else { 94 debug_pagealloc_map_pages(page, 1); 95 } 96 } 97 98 static inline void hibernate_unmap_page(struct page *page) 99 { 100 if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) { 101 unsigned long addr = (unsigned long)page_address(page); 102 int ret = set_direct_map_invalid_noflush(page); 103 104 if (ret) 105 pr_warn_once("Failed to remap page\n"); 106 107 flush_tlb_kernel_range(addr, addr + PAGE_SIZE); 108 } else { 109 debug_pagealloc_unmap_pages(page, 1); 110 } 111 } 112 113 static int swsusp_page_is_free(struct page *); 114 static void swsusp_set_page_forbidden(struct page *); 115 static void swsusp_unset_page_forbidden(struct page *); 116 117 /* 118 * Number of bytes to reserve for memory allocations made by device drivers 119 * from their ->freeze() and ->freeze_noirq() callbacks so that they don't 120 * cause image creation to fail (tunable via /sys/power/reserved_size). 121 */ 122 unsigned long reserved_size; 123 124 void __init hibernate_reserved_size_init(void) 125 { 126 reserved_size = SPARE_PAGES * PAGE_SIZE; 127 } 128 129 /* 130 * Preferred image size in bytes (tunable via /sys/power/image_size). 131 * When it is set to N, swsusp will do its best to ensure the image 132 * size will not exceed N bytes, but if that is impossible, it will 133 * try to create the smallest image possible. 134 */ 135 unsigned long image_size; 136 137 void __init hibernate_image_size_init(void) 138 { 139 image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE; 140 } 141 142 /* 143 * List of PBEs needed for restoring the pages that were allocated before 144 * the suspend and included in the suspend image, but have also been 145 * allocated by the "resume" kernel, so their contents cannot be written 146 * directly to their "original" page frames. 147 */ 148 struct pbe *restore_pblist; 149 150 /* struct linked_page is used to build chains of pages */ 151 152 #define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *)) 153 154 struct linked_page { 155 struct linked_page *next; 156 char data[LINKED_PAGE_DATA_SIZE]; 157 } __packed; 158 159 /* 160 * List of "safe" pages (ie. pages that were not used by the image kernel 161 * before hibernation) that may be used as temporary storage for image kernel 162 * memory contents. 163 */ 164 static struct linked_page *safe_pages_list; 165 166 /* Pointer to an auxiliary buffer (1 page) */ 167 static void *buffer; 168 169 #define PG_ANY 0 170 #define PG_SAFE 1 171 #define PG_UNSAFE_CLEAR 1 172 #define PG_UNSAFE_KEEP 0 173 174 static unsigned int allocated_unsafe_pages; 175 176 /** 177 * get_image_page - Allocate a page for a hibernation image. 178 * @gfp_mask: GFP mask for the allocation. 179 * @safe_needed: Get pages that were not used before hibernation (restore only) 180 * 181 * During image restoration, for storing the PBE list and the image data, we can 182 * only use memory pages that do not conflict with the pages used before 183 * hibernation. The "unsafe" pages have PageNosaveFree set and we count them 184 * using allocated_unsafe_pages. 185 * 186 * Each allocated image page is marked as PageNosave and PageNosaveFree so that 187 * swsusp_free() can release it. 188 */ 189 static void *get_image_page(gfp_t gfp_mask, int safe_needed) 190 { 191 void *res; 192 193 res = (void *)get_zeroed_page(gfp_mask); 194 if (safe_needed) 195 while (res && swsusp_page_is_free(virt_to_page(res))) { 196 /* The page is unsafe, mark it for swsusp_free() */ 197 swsusp_set_page_forbidden(virt_to_page(res)); 198 allocated_unsafe_pages++; 199 res = (void *)get_zeroed_page(gfp_mask); 200 } 201 if (res) { 202 swsusp_set_page_forbidden(virt_to_page(res)); 203 swsusp_set_page_free(virt_to_page(res)); 204 } 205 return res; 206 } 207 208 static void *__get_safe_page(gfp_t gfp_mask) 209 { 210 if (safe_pages_list) { 211 void *ret = safe_pages_list; 212 213 safe_pages_list = safe_pages_list->next; 214 memset(ret, 0, PAGE_SIZE); 215 return ret; 216 } 217 return get_image_page(gfp_mask, PG_SAFE); 218 } 219 220 unsigned long get_safe_page(gfp_t gfp_mask) 221 { 222 return (unsigned long)__get_safe_page(gfp_mask); 223 } 224 225 static struct page *alloc_image_page(gfp_t gfp_mask) 226 { 227 struct page *page; 228 229 page = alloc_page(gfp_mask); 230 if (page) { 231 swsusp_set_page_forbidden(page); 232 swsusp_set_page_free(page); 233 } 234 return page; 235 } 236 237 static void recycle_safe_page(void *page_address) 238 { 239 struct linked_page *lp = page_address; 240 241 lp->next = safe_pages_list; 242 safe_pages_list = lp; 243 } 244 245 /** 246 * free_image_page - Free a page allocated for hibernation image. 247 * @addr: Address of the page to free. 248 * @clear_nosave_free: If set, clear the PageNosaveFree bit for the page. 249 * 250 * The page to free should have been allocated by get_image_page() (page flags 251 * set by it are affected). 252 */ 253 static inline void free_image_page(void *addr, int clear_nosave_free) 254 { 255 struct page *page; 256 257 BUG_ON(!virt_addr_valid(addr)); 258 259 page = virt_to_page(addr); 260 261 swsusp_unset_page_forbidden(page); 262 if (clear_nosave_free) 263 swsusp_unset_page_free(page); 264 265 __free_page(page); 266 } 267 268 static inline void free_list_of_pages(struct linked_page *list, 269 int clear_page_nosave) 270 { 271 while (list) { 272 struct linked_page *lp = list->next; 273 274 free_image_page(list, clear_page_nosave); 275 list = lp; 276 } 277 } 278 279 /* 280 * struct chain_allocator is used for allocating small objects out of 281 * a linked list of pages called 'the chain'. 282 * 283 * The chain grows each time when there is no room for a new object in 284 * the current page. The allocated objects cannot be freed individually. 285 * It is only possible to free them all at once, by freeing the entire 286 * chain. 287 * 288 * NOTE: The chain allocator may be inefficient if the allocated objects 289 * are not much smaller than PAGE_SIZE. 290 */ 291 struct chain_allocator { 292 struct linked_page *chain; /* the chain */ 293 unsigned int used_space; /* total size of objects allocated out 294 of the current page */ 295 gfp_t gfp_mask; /* mask for allocating pages */ 296 int safe_needed; /* if set, only "safe" pages are allocated */ 297 }; 298 299 static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask, 300 int safe_needed) 301 { 302 ca->chain = NULL; 303 ca->used_space = LINKED_PAGE_DATA_SIZE; 304 ca->gfp_mask = gfp_mask; 305 ca->safe_needed = safe_needed; 306 } 307 308 static void *chain_alloc(struct chain_allocator *ca, unsigned int size) 309 { 310 void *ret; 311 312 if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) { 313 struct linked_page *lp; 314 315 lp = ca->safe_needed ? __get_safe_page(ca->gfp_mask) : 316 get_image_page(ca->gfp_mask, PG_ANY); 317 if (!lp) 318 return NULL; 319 320 lp->next = ca->chain; 321 ca->chain = lp; 322 ca->used_space = 0; 323 } 324 ret = ca->chain->data + ca->used_space; 325 ca->used_space += size; 326 return ret; 327 } 328 329 /** 330 * Data types related to memory bitmaps. 331 * 332 * Memory bitmap is a structure consisting of many linked lists of 333 * objects. The main list's elements are of type struct zone_bitmap 334 * and each of them corresonds to one zone. For each zone bitmap 335 * object there is a list of objects of type struct bm_block that 336 * represent each blocks of bitmap in which information is stored. 337 * 338 * struct memory_bitmap contains a pointer to the main list of zone 339 * bitmap objects, a struct bm_position used for browsing the bitmap, 340 * and a pointer to the list of pages used for allocating all of the 341 * zone bitmap objects and bitmap block objects. 342 * 343 * NOTE: It has to be possible to lay out the bitmap in memory 344 * using only allocations of order 0. Additionally, the bitmap is 345 * designed to work with arbitrary number of zones (this is over the 346 * top for now, but let's avoid making unnecessary assumptions ;-). 347 * 348 * struct zone_bitmap contains a pointer to a list of bitmap block 349 * objects and a pointer to the bitmap block object that has been 350 * most recently used for setting bits. Additionally, it contains the 351 * PFNs that correspond to the start and end of the represented zone. 352 * 353 * struct bm_block contains a pointer to the memory page in which 354 * information is stored (in the form of a block of bitmap) 355 * It also contains the pfns that correspond to the start and end of 356 * the represented memory area. 357 * 358 * The memory bitmap is organized as a radix tree to guarantee fast random 359 * access to the bits. There is one radix tree for each zone (as returned 360 * from create_mem_extents). 361 * 362 * One radix tree is represented by one struct mem_zone_bm_rtree. There are 363 * two linked lists for the nodes of the tree, one for the inner nodes and 364 * one for the leave nodes. The linked leave nodes are used for fast linear 365 * access of the memory bitmap. 366 * 367 * The struct rtree_node represents one node of the radix tree. 368 */ 369 370 #define BM_END_OF_MAP (~0UL) 371 372 #define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE) 373 #define BM_BLOCK_SHIFT (PAGE_SHIFT + 3) 374 #define BM_BLOCK_MASK ((1UL << BM_BLOCK_SHIFT) - 1) 375 376 /* 377 * struct rtree_node is a wrapper struct to link the nodes 378 * of the rtree together for easy linear iteration over 379 * bits and easy freeing 380 */ 381 struct rtree_node { 382 struct list_head list; 383 unsigned long *data; 384 }; 385 386 /* 387 * struct mem_zone_bm_rtree represents a bitmap used for one 388 * populated memory zone. 389 */ 390 struct mem_zone_bm_rtree { 391 struct list_head list; /* Link Zones together */ 392 struct list_head nodes; /* Radix Tree inner nodes */ 393 struct list_head leaves; /* Radix Tree leaves */ 394 unsigned long start_pfn; /* Zone start page frame */ 395 unsigned long end_pfn; /* Zone end page frame + 1 */ 396 struct rtree_node *rtree; /* Radix Tree Root */ 397 int levels; /* Number of Radix Tree Levels */ 398 unsigned int blocks; /* Number of Bitmap Blocks */ 399 }; 400 401 /* strcut bm_position is used for browsing memory bitmaps */ 402 403 struct bm_position { 404 struct mem_zone_bm_rtree *zone; 405 struct rtree_node *node; 406 unsigned long node_pfn; 407 int node_bit; 408 }; 409 410 struct memory_bitmap { 411 struct list_head zones; 412 struct linked_page *p_list; /* list of pages used to store zone 413 bitmap objects and bitmap block 414 objects */ 415 struct bm_position cur; /* most recently used bit position */ 416 }; 417 418 /* Functions that operate on memory bitmaps */ 419 420 #define BM_ENTRIES_PER_LEVEL (PAGE_SIZE / sizeof(unsigned long)) 421 #if BITS_PER_LONG == 32 422 #define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 2) 423 #else 424 #define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 3) 425 #endif 426 #define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1) 427 428 /** 429 * alloc_rtree_node - Allocate a new node and add it to the radix tree. 430 * 431 * This function is used to allocate inner nodes as well as the 432 * leave nodes of the radix tree. It also adds the node to the 433 * corresponding linked list passed in by the *list parameter. 434 */ 435 static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed, 436 struct chain_allocator *ca, 437 struct list_head *list) 438 { 439 struct rtree_node *node; 440 441 node = chain_alloc(ca, sizeof(struct rtree_node)); 442 if (!node) 443 return NULL; 444 445 node->data = get_image_page(gfp_mask, safe_needed); 446 if (!node->data) 447 return NULL; 448 449 list_add_tail(&node->list, list); 450 451 return node; 452 } 453 454 /** 455 * add_rtree_block - Add a new leave node to the radix tree. 456 * 457 * The leave nodes need to be allocated in order to keep the leaves 458 * linked list in order. This is guaranteed by the zone->blocks 459 * counter. 460 */ 461 static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask, 462 int safe_needed, struct chain_allocator *ca) 463 { 464 struct rtree_node *node, *block, **dst; 465 unsigned int levels_needed, block_nr; 466 int i; 467 468 block_nr = zone->blocks; 469 levels_needed = 0; 470 471 /* How many levels do we need for this block nr? */ 472 while (block_nr) { 473 levels_needed += 1; 474 block_nr >>= BM_RTREE_LEVEL_SHIFT; 475 } 476 477 /* Make sure the rtree has enough levels */ 478 for (i = zone->levels; i < levels_needed; i++) { 479 node = alloc_rtree_node(gfp_mask, safe_needed, ca, 480 &zone->nodes); 481 if (!node) 482 return -ENOMEM; 483 484 node->data[0] = (unsigned long)zone->rtree; 485 zone->rtree = node; 486 zone->levels += 1; 487 } 488 489 /* Allocate new block */ 490 block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves); 491 if (!block) 492 return -ENOMEM; 493 494 /* Now walk the rtree to insert the block */ 495 node = zone->rtree; 496 dst = &zone->rtree; 497 block_nr = zone->blocks; 498 for (i = zone->levels; i > 0; i--) { 499 int index; 500 501 if (!node) { 502 node = alloc_rtree_node(gfp_mask, safe_needed, ca, 503 &zone->nodes); 504 if (!node) 505 return -ENOMEM; 506 *dst = node; 507 } 508 509 index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT); 510 index &= BM_RTREE_LEVEL_MASK; 511 dst = (struct rtree_node **)&((*dst)->data[index]); 512 node = *dst; 513 } 514 515 zone->blocks += 1; 516 *dst = block; 517 518 return 0; 519 } 520 521 static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone, 522 int clear_nosave_free); 523 524 /** 525 * create_zone_bm_rtree - Create a radix tree for one zone. 526 * 527 * Allocated the mem_zone_bm_rtree structure and initializes it. 528 * This function also allocated and builds the radix tree for the 529 * zone. 530 */ 531 static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask, 532 int safe_needed, 533 struct chain_allocator *ca, 534 unsigned long start, 535 unsigned long end) 536 { 537 struct mem_zone_bm_rtree *zone; 538 unsigned int i, nr_blocks; 539 unsigned long pages; 540 541 pages = end - start; 542 zone = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree)); 543 if (!zone) 544 return NULL; 545 546 INIT_LIST_HEAD(&zone->nodes); 547 INIT_LIST_HEAD(&zone->leaves); 548 zone->start_pfn = start; 549 zone->end_pfn = end; 550 nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK); 551 552 for (i = 0; i < nr_blocks; i++) { 553 if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) { 554 free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR); 555 return NULL; 556 } 557 } 558 559 return zone; 560 } 561 562 /** 563 * free_zone_bm_rtree - Free the memory of the radix tree. 564 * 565 * Free all node pages of the radix tree. The mem_zone_bm_rtree 566 * structure itself is not freed here nor are the rtree_node 567 * structs. 568 */ 569 static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone, 570 int clear_nosave_free) 571 { 572 struct rtree_node *node; 573 574 list_for_each_entry(node, &zone->nodes, list) 575 free_image_page(node->data, clear_nosave_free); 576 577 list_for_each_entry(node, &zone->leaves, list) 578 free_image_page(node->data, clear_nosave_free); 579 } 580 581 static void memory_bm_position_reset(struct memory_bitmap *bm) 582 { 583 bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree, 584 list); 585 bm->cur.node = list_entry(bm->cur.zone->leaves.next, 586 struct rtree_node, list); 587 bm->cur.node_pfn = 0; 588 bm->cur.node_bit = 0; 589 } 590 591 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free); 592 593 struct mem_extent { 594 struct list_head hook; 595 unsigned long start; 596 unsigned long end; 597 }; 598 599 /** 600 * free_mem_extents - Free a list of memory extents. 601 * @list: List of extents to free. 602 */ 603 static void free_mem_extents(struct list_head *list) 604 { 605 struct mem_extent *ext, *aux; 606 607 list_for_each_entry_safe(ext, aux, list, hook) { 608 list_del(&ext->hook); 609 kfree(ext); 610 } 611 } 612 613 /** 614 * create_mem_extents - Create a list of memory extents. 615 * @list: List to put the extents into. 616 * @gfp_mask: Mask to use for memory allocations. 617 * 618 * The extents represent contiguous ranges of PFNs. 619 */ 620 static int create_mem_extents(struct list_head *list, gfp_t gfp_mask) 621 { 622 struct zone *zone; 623 624 INIT_LIST_HEAD(list); 625 626 for_each_populated_zone(zone) { 627 unsigned long zone_start, zone_end; 628 struct mem_extent *ext, *cur, *aux; 629 630 zone_start = zone->zone_start_pfn; 631 zone_end = zone_end_pfn(zone); 632 633 list_for_each_entry(ext, list, hook) 634 if (zone_start <= ext->end) 635 break; 636 637 if (&ext->hook == list || zone_end < ext->start) { 638 /* New extent is necessary */ 639 struct mem_extent *new_ext; 640 641 new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask); 642 if (!new_ext) { 643 free_mem_extents(list); 644 return -ENOMEM; 645 } 646 new_ext->start = zone_start; 647 new_ext->end = zone_end; 648 list_add_tail(&new_ext->hook, &ext->hook); 649 continue; 650 } 651 652 /* Merge this zone's range of PFNs with the existing one */ 653 if (zone_start < ext->start) 654 ext->start = zone_start; 655 if (zone_end > ext->end) 656 ext->end = zone_end; 657 658 /* More merging may be possible */ 659 cur = ext; 660 list_for_each_entry_safe_continue(cur, aux, list, hook) { 661 if (zone_end < cur->start) 662 break; 663 if (zone_end < cur->end) 664 ext->end = cur->end; 665 list_del(&cur->hook); 666 kfree(cur); 667 } 668 } 669 670 return 0; 671 } 672 673 /** 674 * memory_bm_create - Allocate memory for a memory bitmap. 675 */ 676 static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, 677 int safe_needed) 678 { 679 struct chain_allocator ca; 680 struct list_head mem_extents; 681 struct mem_extent *ext; 682 int error; 683 684 chain_init(&ca, gfp_mask, safe_needed); 685 INIT_LIST_HEAD(&bm->zones); 686 687 error = create_mem_extents(&mem_extents, gfp_mask); 688 if (error) 689 return error; 690 691 list_for_each_entry(ext, &mem_extents, hook) { 692 struct mem_zone_bm_rtree *zone; 693 694 zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca, 695 ext->start, ext->end); 696 if (!zone) { 697 error = -ENOMEM; 698 goto Error; 699 } 700 list_add_tail(&zone->list, &bm->zones); 701 } 702 703 bm->p_list = ca.chain; 704 memory_bm_position_reset(bm); 705 Exit: 706 free_mem_extents(&mem_extents); 707 return error; 708 709 Error: 710 bm->p_list = ca.chain; 711 memory_bm_free(bm, PG_UNSAFE_CLEAR); 712 goto Exit; 713 } 714 715 /** 716 * memory_bm_free - Free memory occupied by the memory bitmap. 717 * @bm: Memory bitmap. 718 */ 719 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free) 720 { 721 struct mem_zone_bm_rtree *zone; 722 723 list_for_each_entry(zone, &bm->zones, list) 724 free_zone_bm_rtree(zone, clear_nosave_free); 725 726 free_list_of_pages(bm->p_list, clear_nosave_free); 727 728 INIT_LIST_HEAD(&bm->zones); 729 } 730 731 /** 732 * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap. 733 * 734 * Find the bit in memory bitmap @bm that corresponds to the given PFN. 735 * The cur.zone, cur.block and cur.node_pfn members of @bm are updated. 736 * 737 * Walk the radix tree to find the page containing the bit that represents @pfn 738 * and return the position of the bit in @addr and @bit_nr. 739 */ 740 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn, 741 void **addr, unsigned int *bit_nr) 742 { 743 struct mem_zone_bm_rtree *curr, *zone; 744 struct rtree_node *node; 745 int i, block_nr; 746 747 zone = bm->cur.zone; 748 749 if (pfn >= zone->start_pfn && pfn < zone->end_pfn) 750 goto zone_found; 751 752 zone = NULL; 753 754 /* Find the right zone */ 755 list_for_each_entry(curr, &bm->zones, list) { 756 if (pfn >= curr->start_pfn && pfn < curr->end_pfn) { 757 zone = curr; 758 break; 759 } 760 } 761 762 if (!zone) 763 return -EFAULT; 764 765 zone_found: 766 /* 767 * We have found the zone. Now walk the radix tree to find the leaf node 768 * for our PFN. 769 */ 770 771 /* 772 * If the zone we wish to scan is the current zone and the 773 * pfn falls into the current node then we do not need to walk 774 * the tree. 775 */ 776 node = bm->cur.node; 777 if (zone == bm->cur.zone && 778 ((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn) 779 goto node_found; 780 781 node = zone->rtree; 782 block_nr = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT; 783 784 for (i = zone->levels; i > 0; i--) { 785 int index; 786 787 index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT); 788 index &= BM_RTREE_LEVEL_MASK; 789 BUG_ON(node->data[index] == 0); 790 node = (struct rtree_node *)node->data[index]; 791 } 792 793 node_found: 794 /* Update last position */ 795 bm->cur.zone = zone; 796 bm->cur.node = node; 797 bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK; 798 799 /* Set return values */ 800 *addr = node->data; 801 *bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK; 802 803 return 0; 804 } 805 806 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn) 807 { 808 void *addr; 809 unsigned int bit; 810 int error; 811 812 error = memory_bm_find_bit(bm, pfn, &addr, &bit); 813 BUG_ON(error); 814 set_bit(bit, addr); 815 } 816 817 static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn) 818 { 819 void *addr; 820 unsigned int bit; 821 int error; 822 823 error = memory_bm_find_bit(bm, pfn, &addr, &bit); 824 if (!error) 825 set_bit(bit, addr); 826 827 return error; 828 } 829 830 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn) 831 { 832 void *addr; 833 unsigned int bit; 834 int error; 835 836 error = memory_bm_find_bit(bm, pfn, &addr, &bit); 837 BUG_ON(error); 838 clear_bit(bit, addr); 839 } 840 841 static void memory_bm_clear_current(struct memory_bitmap *bm) 842 { 843 int bit; 844 845 bit = max(bm->cur.node_bit - 1, 0); 846 clear_bit(bit, bm->cur.node->data); 847 } 848 849 static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn) 850 { 851 void *addr; 852 unsigned int bit; 853 int error; 854 855 error = memory_bm_find_bit(bm, pfn, &addr, &bit); 856 BUG_ON(error); 857 return test_bit(bit, addr); 858 } 859 860 static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn) 861 { 862 void *addr; 863 unsigned int bit; 864 865 return !memory_bm_find_bit(bm, pfn, &addr, &bit); 866 } 867 868 /* 869 * rtree_next_node - Jump to the next leaf node. 870 * 871 * Set the position to the beginning of the next node in the 872 * memory bitmap. This is either the next node in the current 873 * zone's radix tree or the first node in the radix tree of the 874 * next zone. 875 * 876 * Return true if there is a next node, false otherwise. 877 */ 878 static bool rtree_next_node(struct memory_bitmap *bm) 879 { 880 if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) { 881 bm->cur.node = list_entry(bm->cur.node->list.next, 882 struct rtree_node, list); 883 bm->cur.node_pfn += BM_BITS_PER_BLOCK; 884 bm->cur.node_bit = 0; 885 touch_softlockup_watchdog(); 886 return true; 887 } 888 889 /* No more nodes, goto next zone */ 890 if (!list_is_last(&bm->cur.zone->list, &bm->zones)) { 891 bm->cur.zone = list_entry(bm->cur.zone->list.next, 892 struct mem_zone_bm_rtree, list); 893 bm->cur.node = list_entry(bm->cur.zone->leaves.next, 894 struct rtree_node, list); 895 bm->cur.node_pfn = 0; 896 bm->cur.node_bit = 0; 897 return true; 898 } 899 900 /* No more zones */ 901 return false; 902 } 903 904 /** 905 * memory_bm_rtree_next_pfn - Find the next set bit in a memory bitmap. 906 * @bm: Memory bitmap. 907 * 908 * Starting from the last returned position this function searches for the next 909 * set bit in @bm and returns the PFN represented by it. If no more bits are 910 * set, BM_END_OF_MAP is returned. 911 * 912 * It is required to run memory_bm_position_reset() before the first call to 913 * this function for the given memory bitmap. 914 */ 915 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm) 916 { 917 unsigned long bits, pfn, pages; 918 int bit; 919 920 do { 921 pages = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn; 922 bits = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK); 923 bit = find_next_bit(bm->cur.node->data, bits, 924 bm->cur.node_bit); 925 if (bit < bits) { 926 pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit; 927 bm->cur.node_bit = bit + 1; 928 return pfn; 929 } 930 } while (rtree_next_node(bm)); 931 932 return BM_END_OF_MAP; 933 } 934 935 /* 936 * This structure represents a range of page frames the contents of which 937 * should not be saved during hibernation. 938 */ 939 struct nosave_region { 940 struct list_head list; 941 unsigned long start_pfn; 942 unsigned long end_pfn; 943 }; 944 945 static LIST_HEAD(nosave_regions); 946 947 static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone) 948 { 949 struct rtree_node *node; 950 951 list_for_each_entry(node, &zone->nodes, list) 952 recycle_safe_page(node->data); 953 954 list_for_each_entry(node, &zone->leaves, list) 955 recycle_safe_page(node->data); 956 } 957 958 static void memory_bm_recycle(struct memory_bitmap *bm) 959 { 960 struct mem_zone_bm_rtree *zone; 961 struct linked_page *p_list; 962 963 list_for_each_entry(zone, &bm->zones, list) 964 recycle_zone_bm_rtree(zone); 965 966 p_list = bm->p_list; 967 while (p_list) { 968 struct linked_page *lp = p_list; 969 970 p_list = lp->next; 971 recycle_safe_page(lp); 972 } 973 } 974 975 /** 976 * register_nosave_region - Register a region of unsaveable memory. 977 * 978 * Register a range of page frames the contents of which should not be saved 979 * during hibernation (to be used in the early initialization code). 980 */ 981 void __init __register_nosave_region(unsigned long start_pfn, 982 unsigned long end_pfn, int use_kmalloc) 983 { 984 struct nosave_region *region; 985 986 if (start_pfn >= end_pfn) 987 return; 988 989 if (!list_empty(&nosave_regions)) { 990 /* Try to extend the previous region (they should be sorted) */ 991 region = list_entry(nosave_regions.prev, 992 struct nosave_region, list); 993 if (region->end_pfn == start_pfn) { 994 region->end_pfn = end_pfn; 995 goto Report; 996 } 997 } 998 if (use_kmalloc) { 999 /* During init, this shouldn't fail */ 1000 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL); 1001 BUG_ON(!region); 1002 } else { 1003 /* This allocation cannot fail */ 1004 region = memblock_alloc(sizeof(struct nosave_region), 1005 SMP_CACHE_BYTES); 1006 if (!region) 1007 panic("%s: Failed to allocate %zu bytes\n", __func__, 1008 sizeof(struct nosave_region)); 1009 } 1010 region->start_pfn = start_pfn; 1011 region->end_pfn = end_pfn; 1012 list_add_tail(®ion->list, &nosave_regions); 1013 Report: 1014 pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n", 1015 (unsigned long long) start_pfn << PAGE_SHIFT, 1016 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1); 1017 } 1018 1019 /* 1020 * Set bits in this map correspond to the page frames the contents of which 1021 * should not be saved during the suspend. 1022 */ 1023 static struct memory_bitmap *forbidden_pages_map; 1024 1025 /* Set bits in this map correspond to free page frames. */ 1026 static struct memory_bitmap *free_pages_map; 1027 1028 /* 1029 * Each page frame allocated for creating the image is marked by setting the 1030 * corresponding bits in forbidden_pages_map and free_pages_map simultaneously 1031 */ 1032 1033 void swsusp_set_page_free(struct page *page) 1034 { 1035 if (free_pages_map) 1036 memory_bm_set_bit(free_pages_map, page_to_pfn(page)); 1037 } 1038 1039 static int swsusp_page_is_free(struct page *page) 1040 { 1041 return free_pages_map ? 1042 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0; 1043 } 1044 1045 void swsusp_unset_page_free(struct page *page) 1046 { 1047 if (free_pages_map) 1048 memory_bm_clear_bit(free_pages_map, page_to_pfn(page)); 1049 } 1050 1051 static void swsusp_set_page_forbidden(struct page *page) 1052 { 1053 if (forbidden_pages_map) 1054 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page)); 1055 } 1056 1057 int swsusp_page_is_forbidden(struct page *page) 1058 { 1059 return forbidden_pages_map ? 1060 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0; 1061 } 1062 1063 static void swsusp_unset_page_forbidden(struct page *page) 1064 { 1065 if (forbidden_pages_map) 1066 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page)); 1067 } 1068 1069 /** 1070 * mark_nosave_pages - Mark pages that should not be saved. 1071 * @bm: Memory bitmap. 1072 * 1073 * Set the bits in @bm that correspond to the page frames the contents of which 1074 * should not be saved. 1075 */ 1076 static void mark_nosave_pages(struct memory_bitmap *bm) 1077 { 1078 struct nosave_region *region; 1079 1080 if (list_empty(&nosave_regions)) 1081 return; 1082 1083 list_for_each_entry(region, &nosave_regions, list) { 1084 unsigned long pfn; 1085 1086 pr_debug("Marking nosave pages: [mem %#010llx-%#010llx]\n", 1087 (unsigned long long) region->start_pfn << PAGE_SHIFT, 1088 ((unsigned long long) region->end_pfn << PAGE_SHIFT) 1089 - 1); 1090 1091 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++) 1092 if (pfn_valid(pfn)) { 1093 /* 1094 * It is safe to ignore the result of 1095 * mem_bm_set_bit_check() here, since we won't 1096 * touch the PFNs for which the error is 1097 * returned anyway. 1098 */ 1099 mem_bm_set_bit_check(bm, pfn); 1100 } 1101 } 1102 } 1103 1104 /** 1105 * create_basic_memory_bitmaps - Create bitmaps to hold basic page information. 1106 * 1107 * Create bitmaps needed for marking page frames that should not be saved and 1108 * free page frames. The forbidden_pages_map and free_pages_map pointers are 1109 * only modified if everything goes well, because we don't want the bits to be 1110 * touched before both bitmaps are set up. 1111 */ 1112 int create_basic_memory_bitmaps(void) 1113 { 1114 struct memory_bitmap *bm1, *bm2; 1115 int error = 0; 1116 1117 if (forbidden_pages_map && free_pages_map) 1118 return 0; 1119 else 1120 BUG_ON(forbidden_pages_map || free_pages_map); 1121 1122 bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL); 1123 if (!bm1) 1124 return -ENOMEM; 1125 1126 error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY); 1127 if (error) 1128 goto Free_first_object; 1129 1130 bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL); 1131 if (!bm2) 1132 goto Free_first_bitmap; 1133 1134 error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY); 1135 if (error) 1136 goto Free_second_object; 1137 1138 forbidden_pages_map = bm1; 1139 free_pages_map = bm2; 1140 mark_nosave_pages(forbidden_pages_map); 1141 1142 pr_debug("Basic memory bitmaps created\n"); 1143 1144 return 0; 1145 1146 Free_second_object: 1147 kfree(bm2); 1148 Free_first_bitmap: 1149 memory_bm_free(bm1, PG_UNSAFE_CLEAR); 1150 Free_first_object: 1151 kfree(bm1); 1152 return -ENOMEM; 1153 } 1154 1155 /** 1156 * free_basic_memory_bitmaps - Free memory bitmaps holding basic information. 1157 * 1158 * Free memory bitmaps allocated by create_basic_memory_bitmaps(). The 1159 * auxiliary pointers are necessary so that the bitmaps themselves are not 1160 * referred to while they are being freed. 1161 */ 1162 void free_basic_memory_bitmaps(void) 1163 { 1164 struct memory_bitmap *bm1, *bm2; 1165 1166 if (WARN_ON(!(forbidden_pages_map && free_pages_map))) 1167 return; 1168 1169 bm1 = forbidden_pages_map; 1170 bm2 = free_pages_map; 1171 forbidden_pages_map = NULL; 1172 free_pages_map = NULL; 1173 memory_bm_free(bm1, PG_UNSAFE_CLEAR); 1174 kfree(bm1); 1175 memory_bm_free(bm2, PG_UNSAFE_CLEAR); 1176 kfree(bm2); 1177 1178 pr_debug("Basic memory bitmaps freed\n"); 1179 } 1180 1181 static void clear_or_poison_free_page(struct page *page) 1182 { 1183 if (page_poisoning_enabled_static()) 1184 __kernel_poison_pages(page, 1); 1185 else if (want_init_on_free()) 1186 clear_highpage(page); 1187 } 1188 1189 void clear_or_poison_free_pages(void) 1190 { 1191 struct memory_bitmap *bm = free_pages_map; 1192 unsigned long pfn; 1193 1194 if (WARN_ON(!(free_pages_map))) 1195 return; 1196 1197 if (page_poisoning_enabled() || want_init_on_free()) { 1198 memory_bm_position_reset(bm); 1199 pfn = memory_bm_next_pfn(bm); 1200 while (pfn != BM_END_OF_MAP) { 1201 if (pfn_valid(pfn)) 1202 clear_or_poison_free_page(pfn_to_page(pfn)); 1203 1204 pfn = memory_bm_next_pfn(bm); 1205 } 1206 memory_bm_position_reset(bm); 1207 pr_info("free pages cleared after restore\n"); 1208 } 1209 } 1210 1211 /** 1212 * snapshot_additional_pages - Estimate the number of extra pages needed. 1213 * @zone: Memory zone to carry out the computation for. 1214 * 1215 * Estimate the number of additional pages needed for setting up a hibernation 1216 * image data structures for @zone (usually, the returned value is greater than 1217 * the exact number). 1218 */ 1219 unsigned int snapshot_additional_pages(struct zone *zone) 1220 { 1221 unsigned int rtree, nodes; 1222 1223 rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK); 1224 rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node), 1225 LINKED_PAGE_DATA_SIZE); 1226 while (nodes > 1) { 1227 nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL); 1228 rtree += nodes; 1229 } 1230 1231 return 2 * rtree; 1232 } 1233 1234 #ifdef CONFIG_HIGHMEM 1235 /** 1236 * count_free_highmem_pages - Compute the total number of free highmem pages. 1237 * 1238 * The returned number is system-wide. 1239 */ 1240 static unsigned int count_free_highmem_pages(void) 1241 { 1242 struct zone *zone; 1243 unsigned int cnt = 0; 1244 1245 for_each_populated_zone(zone) 1246 if (is_highmem(zone)) 1247 cnt += zone_page_state(zone, NR_FREE_PAGES); 1248 1249 return cnt; 1250 } 1251 1252 /** 1253 * saveable_highmem_page - Check if a highmem page is saveable. 1254 * 1255 * Determine whether a highmem page should be included in a hibernation image. 1256 * 1257 * We should save the page if it isn't Nosave or NosaveFree, or Reserved, 1258 * and it isn't part of a free chunk of pages. 1259 */ 1260 static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn) 1261 { 1262 struct page *page; 1263 1264 if (!pfn_valid(pfn)) 1265 return NULL; 1266 1267 page = pfn_to_online_page(pfn); 1268 if (!page || page_zone(page) != zone) 1269 return NULL; 1270 1271 BUG_ON(!PageHighMem(page)); 1272 1273 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page)) 1274 return NULL; 1275 1276 if (PageReserved(page) || PageOffline(page)) 1277 return NULL; 1278 1279 if (page_is_guard(page)) 1280 return NULL; 1281 1282 return page; 1283 } 1284 1285 /** 1286 * count_highmem_pages - Compute the total number of saveable highmem pages. 1287 */ 1288 static unsigned int count_highmem_pages(void) 1289 { 1290 struct zone *zone; 1291 unsigned int n = 0; 1292 1293 for_each_populated_zone(zone) { 1294 unsigned long pfn, max_zone_pfn; 1295 1296 if (!is_highmem(zone)) 1297 continue; 1298 1299 mark_free_pages(zone); 1300 max_zone_pfn = zone_end_pfn(zone); 1301 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) 1302 if (saveable_highmem_page(zone, pfn)) 1303 n++; 1304 } 1305 return n; 1306 } 1307 #else 1308 static inline void *saveable_highmem_page(struct zone *z, unsigned long p) 1309 { 1310 return NULL; 1311 } 1312 #endif /* CONFIG_HIGHMEM */ 1313 1314 /** 1315 * saveable_page - Check if the given page is saveable. 1316 * 1317 * Determine whether a non-highmem page should be included in a hibernation 1318 * image. 1319 * 1320 * We should save the page if it isn't Nosave, and is not in the range 1321 * of pages statically defined as 'unsaveable', and it isn't part of 1322 * a free chunk of pages. 1323 */ 1324 static struct page *saveable_page(struct zone *zone, unsigned long pfn) 1325 { 1326 struct page *page; 1327 1328 if (!pfn_valid(pfn)) 1329 return NULL; 1330 1331 page = pfn_to_online_page(pfn); 1332 if (!page || page_zone(page) != zone) 1333 return NULL; 1334 1335 BUG_ON(PageHighMem(page)); 1336 1337 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page)) 1338 return NULL; 1339 1340 if (PageOffline(page)) 1341 return NULL; 1342 1343 if (PageReserved(page) 1344 && (!kernel_page_present(page) || pfn_is_nosave(pfn))) 1345 return NULL; 1346 1347 if (page_is_guard(page)) 1348 return NULL; 1349 1350 return page; 1351 } 1352 1353 /** 1354 * count_data_pages - Compute the total number of saveable non-highmem pages. 1355 */ 1356 static unsigned int count_data_pages(void) 1357 { 1358 struct zone *zone; 1359 unsigned long pfn, max_zone_pfn; 1360 unsigned int n = 0; 1361 1362 for_each_populated_zone(zone) { 1363 if (is_highmem(zone)) 1364 continue; 1365 1366 mark_free_pages(zone); 1367 max_zone_pfn = zone_end_pfn(zone); 1368 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) 1369 if (saveable_page(zone, pfn)) 1370 n++; 1371 } 1372 return n; 1373 } 1374 1375 /* 1376 * This is needed, because copy_page and memcpy are not usable for copying 1377 * task structs. 1378 */ 1379 static inline void do_copy_page(long *dst, long *src) 1380 { 1381 int n; 1382 1383 for (n = PAGE_SIZE / sizeof(long); n; n--) 1384 *dst++ = *src++; 1385 } 1386 1387 /** 1388 * safe_copy_page - Copy a page in a safe way. 1389 * 1390 * Check if the page we are going to copy is marked as present in the kernel 1391 * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or 1392 * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present() 1393 * always returns 'true'. 1394 */ 1395 static void safe_copy_page(void *dst, struct page *s_page) 1396 { 1397 if (kernel_page_present(s_page)) { 1398 do_copy_page(dst, page_address(s_page)); 1399 } else { 1400 hibernate_map_page(s_page); 1401 do_copy_page(dst, page_address(s_page)); 1402 hibernate_unmap_page(s_page); 1403 } 1404 } 1405 1406 #ifdef CONFIG_HIGHMEM 1407 static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn) 1408 { 1409 return is_highmem(zone) ? 1410 saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn); 1411 } 1412 1413 static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) 1414 { 1415 struct page *s_page, *d_page; 1416 void *src, *dst; 1417 1418 s_page = pfn_to_page(src_pfn); 1419 d_page = pfn_to_page(dst_pfn); 1420 if (PageHighMem(s_page)) { 1421 src = kmap_atomic(s_page); 1422 dst = kmap_atomic(d_page); 1423 do_copy_page(dst, src); 1424 kunmap_atomic(dst); 1425 kunmap_atomic(src); 1426 } else { 1427 if (PageHighMem(d_page)) { 1428 /* 1429 * The page pointed to by src may contain some kernel 1430 * data modified by kmap_atomic() 1431 */ 1432 safe_copy_page(buffer, s_page); 1433 dst = kmap_atomic(d_page); 1434 copy_page(dst, buffer); 1435 kunmap_atomic(dst); 1436 } else { 1437 safe_copy_page(page_address(d_page), s_page); 1438 } 1439 } 1440 } 1441 #else 1442 #define page_is_saveable(zone, pfn) saveable_page(zone, pfn) 1443 1444 static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn) 1445 { 1446 safe_copy_page(page_address(pfn_to_page(dst_pfn)), 1447 pfn_to_page(src_pfn)); 1448 } 1449 #endif /* CONFIG_HIGHMEM */ 1450 1451 static void copy_data_pages(struct memory_bitmap *copy_bm, 1452 struct memory_bitmap *orig_bm) 1453 { 1454 struct zone *zone; 1455 unsigned long pfn; 1456 1457 for_each_populated_zone(zone) { 1458 unsigned long max_zone_pfn; 1459 1460 mark_free_pages(zone); 1461 max_zone_pfn = zone_end_pfn(zone); 1462 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++) 1463 if (page_is_saveable(zone, pfn)) 1464 memory_bm_set_bit(orig_bm, pfn); 1465 } 1466 memory_bm_position_reset(orig_bm); 1467 memory_bm_position_reset(copy_bm); 1468 for(;;) { 1469 pfn = memory_bm_next_pfn(orig_bm); 1470 if (unlikely(pfn == BM_END_OF_MAP)) 1471 break; 1472 copy_data_page(memory_bm_next_pfn(copy_bm), pfn); 1473 } 1474 } 1475 1476 /* Total number of image pages */ 1477 static unsigned int nr_copy_pages; 1478 /* Number of pages needed for saving the original pfns of the image pages */ 1479 static unsigned int nr_meta_pages; 1480 /* 1481 * Numbers of normal and highmem page frames allocated for hibernation image 1482 * before suspending devices. 1483 */ 1484 static unsigned int alloc_normal, alloc_highmem; 1485 /* 1486 * Memory bitmap used for marking saveable pages (during hibernation) or 1487 * hibernation image pages (during restore) 1488 */ 1489 static struct memory_bitmap orig_bm; 1490 /* 1491 * Memory bitmap used during hibernation for marking allocated page frames that 1492 * will contain copies of saveable pages. During restore it is initially used 1493 * for marking hibernation image pages, but then the set bits from it are 1494 * duplicated in @orig_bm and it is released. On highmem systems it is next 1495 * used for marking "safe" highmem pages, but it has to be reinitialized for 1496 * this purpose. 1497 */ 1498 static struct memory_bitmap copy_bm; 1499 1500 /** 1501 * swsusp_free - Free pages allocated for hibernation image. 1502 * 1503 * Image pages are alocated before snapshot creation, so they need to be 1504 * released after resume. 1505 */ 1506 void swsusp_free(void) 1507 { 1508 unsigned long fb_pfn, fr_pfn; 1509 1510 if (!forbidden_pages_map || !free_pages_map) 1511 goto out; 1512 1513 memory_bm_position_reset(forbidden_pages_map); 1514 memory_bm_position_reset(free_pages_map); 1515 1516 loop: 1517 fr_pfn = memory_bm_next_pfn(free_pages_map); 1518 fb_pfn = memory_bm_next_pfn(forbidden_pages_map); 1519 1520 /* 1521 * Find the next bit set in both bitmaps. This is guaranteed to 1522 * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP. 1523 */ 1524 do { 1525 if (fb_pfn < fr_pfn) 1526 fb_pfn = memory_bm_next_pfn(forbidden_pages_map); 1527 if (fr_pfn < fb_pfn) 1528 fr_pfn = memory_bm_next_pfn(free_pages_map); 1529 } while (fb_pfn != fr_pfn); 1530 1531 if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) { 1532 struct page *page = pfn_to_page(fr_pfn); 1533 1534 memory_bm_clear_current(forbidden_pages_map); 1535 memory_bm_clear_current(free_pages_map); 1536 hibernate_restore_unprotect_page(page_address(page)); 1537 __free_page(page); 1538 goto loop; 1539 } 1540 1541 out: 1542 nr_copy_pages = 0; 1543 nr_meta_pages = 0; 1544 restore_pblist = NULL; 1545 buffer = NULL; 1546 alloc_normal = 0; 1547 alloc_highmem = 0; 1548 hibernate_restore_protection_end(); 1549 } 1550 1551 /* Helper functions used for the shrinking of memory. */ 1552 1553 #define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN) 1554 1555 /** 1556 * preallocate_image_pages - Allocate a number of pages for hibernation image. 1557 * @nr_pages: Number of page frames to allocate. 1558 * @mask: GFP flags to use for the allocation. 1559 * 1560 * Return value: Number of page frames actually allocated 1561 */ 1562 static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask) 1563 { 1564 unsigned long nr_alloc = 0; 1565 1566 while (nr_pages > 0) { 1567 struct page *page; 1568 1569 page = alloc_image_page(mask); 1570 if (!page) 1571 break; 1572 memory_bm_set_bit(©_bm, page_to_pfn(page)); 1573 if (PageHighMem(page)) 1574 alloc_highmem++; 1575 else 1576 alloc_normal++; 1577 nr_pages--; 1578 nr_alloc++; 1579 } 1580 1581 return nr_alloc; 1582 } 1583 1584 static unsigned long preallocate_image_memory(unsigned long nr_pages, 1585 unsigned long avail_normal) 1586 { 1587 unsigned long alloc; 1588 1589 if (avail_normal <= alloc_normal) 1590 return 0; 1591 1592 alloc = avail_normal - alloc_normal; 1593 if (nr_pages < alloc) 1594 alloc = nr_pages; 1595 1596 return preallocate_image_pages(alloc, GFP_IMAGE); 1597 } 1598 1599 #ifdef CONFIG_HIGHMEM 1600 static unsigned long preallocate_image_highmem(unsigned long nr_pages) 1601 { 1602 return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM); 1603 } 1604 1605 /** 1606 * __fraction - Compute (an approximation of) x * (multiplier / base). 1607 */ 1608 static unsigned long __fraction(u64 x, u64 multiplier, u64 base) 1609 { 1610 return div64_u64(x * multiplier, base); 1611 } 1612 1613 static unsigned long preallocate_highmem_fraction(unsigned long nr_pages, 1614 unsigned long highmem, 1615 unsigned long total) 1616 { 1617 unsigned long alloc = __fraction(nr_pages, highmem, total); 1618 1619 return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM); 1620 } 1621 #else /* CONFIG_HIGHMEM */ 1622 static inline unsigned long preallocate_image_highmem(unsigned long nr_pages) 1623 { 1624 return 0; 1625 } 1626 1627 static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages, 1628 unsigned long highmem, 1629 unsigned long total) 1630 { 1631 return 0; 1632 } 1633 #endif /* CONFIG_HIGHMEM */ 1634 1635 /** 1636 * free_unnecessary_pages - Release preallocated pages not needed for the image. 1637 */ 1638 static unsigned long free_unnecessary_pages(void) 1639 { 1640 unsigned long save, to_free_normal, to_free_highmem, free; 1641 1642 save = count_data_pages(); 1643 if (alloc_normal >= save) { 1644 to_free_normal = alloc_normal - save; 1645 save = 0; 1646 } else { 1647 to_free_normal = 0; 1648 save -= alloc_normal; 1649 } 1650 save += count_highmem_pages(); 1651 if (alloc_highmem >= save) { 1652 to_free_highmem = alloc_highmem - save; 1653 } else { 1654 to_free_highmem = 0; 1655 save -= alloc_highmem; 1656 if (to_free_normal > save) 1657 to_free_normal -= save; 1658 else 1659 to_free_normal = 0; 1660 } 1661 free = to_free_normal + to_free_highmem; 1662 1663 memory_bm_position_reset(©_bm); 1664 1665 while (to_free_normal > 0 || to_free_highmem > 0) { 1666 unsigned long pfn = memory_bm_next_pfn(©_bm); 1667 struct page *page = pfn_to_page(pfn); 1668 1669 if (PageHighMem(page)) { 1670 if (!to_free_highmem) 1671 continue; 1672 to_free_highmem--; 1673 alloc_highmem--; 1674 } else { 1675 if (!to_free_normal) 1676 continue; 1677 to_free_normal--; 1678 alloc_normal--; 1679 } 1680 memory_bm_clear_bit(©_bm, pfn); 1681 swsusp_unset_page_forbidden(page); 1682 swsusp_unset_page_free(page); 1683 __free_page(page); 1684 } 1685 1686 return free; 1687 } 1688 1689 /** 1690 * minimum_image_size - Estimate the minimum acceptable size of an image. 1691 * @saveable: Number of saveable pages in the system. 1692 * 1693 * We want to avoid attempting to free too much memory too hard, so estimate the 1694 * minimum acceptable size of a hibernation image to use as the lower limit for 1695 * preallocating memory. 1696 * 1697 * We assume that the minimum image size should be proportional to 1698 * 1699 * [number of saveable pages] - [number of pages that can be freed in theory] 1700 * 1701 * where the second term is the sum of (1) reclaimable slab pages, (2) active 1702 * and (3) inactive anonymous pages, (4) active and (5) inactive file pages. 1703 */ 1704 static unsigned long minimum_image_size(unsigned long saveable) 1705 { 1706 unsigned long size; 1707 1708 size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B) 1709 + global_node_page_state(NR_ACTIVE_ANON) 1710 + global_node_page_state(NR_INACTIVE_ANON) 1711 + global_node_page_state(NR_ACTIVE_FILE) 1712 + global_node_page_state(NR_INACTIVE_FILE); 1713 1714 return saveable <= size ? 0 : saveable - size; 1715 } 1716 1717 /** 1718 * hibernate_preallocate_memory - Preallocate memory for hibernation image. 1719 * 1720 * To create a hibernation image it is necessary to make a copy of every page 1721 * frame in use. We also need a number of page frames to be free during 1722 * hibernation for allocations made while saving the image and for device 1723 * drivers, in case they need to allocate memory from their hibernation 1724 * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough 1725 * estimate) and reserved_size divided by PAGE_SIZE (which is tunable through 1726 * /sys/power/reserved_size, respectively). To make this happen, we compute the 1727 * total number of available page frames and allocate at least 1728 * 1729 * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2 1730 * + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE) 1731 * 1732 * of them, which corresponds to the maximum size of a hibernation image. 1733 * 1734 * If image_size is set below the number following from the above formula, 1735 * the preallocation of memory is continued until the total number of saveable 1736 * pages in the system is below the requested image size or the minimum 1737 * acceptable image size returned by minimum_image_size(), whichever is greater. 1738 */ 1739 int hibernate_preallocate_memory(void) 1740 { 1741 struct zone *zone; 1742 unsigned long saveable, size, max_size, count, highmem, pages = 0; 1743 unsigned long alloc, save_highmem, pages_highmem, avail_normal; 1744 ktime_t start, stop; 1745 int error; 1746 1747 pr_info("Preallocating image memory\n"); 1748 start = ktime_get(); 1749 1750 error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY); 1751 if (error) { 1752 pr_err("Cannot allocate original bitmap\n"); 1753 goto err_out; 1754 } 1755 1756 error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY); 1757 if (error) { 1758 pr_err("Cannot allocate copy bitmap\n"); 1759 goto err_out; 1760 } 1761 1762 alloc_normal = 0; 1763 alloc_highmem = 0; 1764 1765 /* Count the number of saveable data pages. */ 1766 save_highmem = count_highmem_pages(); 1767 saveable = count_data_pages(); 1768 1769 /* 1770 * Compute the total number of page frames we can use (count) and the 1771 * number of pages needed for image metadata (size). 1772 */ 1773 count = saveable; 1774 saveable += save_highmem; 1775 highmem = save_highmem; 1776 size = 0; 1777 for_each_populated_zone(zone) { 1778 size += snapshot_additional_pages(zone); 1779 if (is_highmem(zone)) 1780 highmem += zone_page_state(zone, NR_FREE_PAGES); 1781 else 1782 count += zone_page_state(zone, NR_FREE_PAGES); 1783 } 1784 avail_normal = count; 1785 count += highmem; 1786 count -= totalreserve_pages; 1787 1788 /* Compute the maximum number of saveable pages to leave in memory. */ 1789 max_size = (count - (size + PAGES_FOR_IO)) / 2 1790 - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE); 1791 /* Compute the desired number of image pages specified by image_size. */ 1792 size = DIV_ROUND_UP(image_size, PAGE_SIZE); 1793 if (size > max_size) 1794 size = max_size; 1795 /* 1796 * If the desired number of image pages is at least as large as the 1797 * current number of saveable pages in memory, allocate page frames for 1798 * the image and we're done. 1799 */ 1800 if (size >= saveable) { 1801 pages = preallocate_image_highmem(save_highmem); 1802 pages += preallocate_image_memory(saveable - pages, avail_normal); 1803 goto out; 1804 } 1805 1806 /* Estimate the minimum size of the image. */ 1807 pages = minimum_image_size(saveable); 1808 /* 1809 * To avoid excessive pressure on the normal zone, leave room in it to 1810 * accommodate an image of the minimum size (unless it's already too 1811 * small, in which case don't preallocate pages from it at all). 1812 */ 1813 if (avail_normal > pages) 1814 avail_normal -= pages; 1815 else 1816 avail_normal = 0; 1817 if (size < pages) 1818 size = min_t(unsigned long, pages, max_size); 1819 1820 /* 1821 * Let the memory management subsystem know that we're going to need a 1822 * large number of page frames to allocate and make it free some memory. 1823 * NOTE: If this is not done, performance will be hurt badly in some 1824 * test cases. 1825 */ 1826 shrink_all_memory(saveable - size); 1827 1828 /* 1829 * The number of saveable pages in memory was too high, so apply some 1830 * pressure to decrease it. First, make room for the largest possible 1831 * image and fail if that doesn't work. Next, try to decrease the size 1832 * of the image as much as indicated by 'size' using allocations from 1833 * highmem and non-highmem zones separately. 1834 */ 1835 pages_highmem = preallocate_image_highmem(highmem / 2); 1836 alloc = count - max_size; 1837 if (alloc > pages_highmem) 1838 alloc -= pages_highmem; 1839 else 1840 alloc = 0; 1841 pages = preallocate_image_memory(alloc, avail_normal); 1842 if (pages < alloc) { 1843 /* We have exhausted non-highmem pages, try highmem. */ 1844 alloc -= pages; 1845 pages += pages_highmem; 1846 pages_highmem = preallocate_image_highmem(alloc); 1847 if (pages_highmem < alloc) { 1848 pr_err("Image allocation is %lu pages short\n", 1849 alloc - pages_highmem); 1850 goto err_out; 1851 } 1852 pages += pages_highmem; 1853 /* 1854 * size is the desired number of saveable pages to leave in 1855 * memory, so try to preallocate (all memory - size) pages. 1856 */ 1857 alloc = (count - pages) - size; 1858 pages += preallocate_image_highmem(alloc); 1859 } else { 1860 /* 1861 * There are approximately max_size saveable pages at this point 1862 * and we want to reduce this number down to size. 1863 */ 1864 alloc = max_size - size; 1865 size = preallocate_highmem_fraction(alloc, highmem, count); 1866 pages_highmem += size; 1867 alloc -= size; 1868 size = preallocate_image_memory(alloc, avail_normal); 1869 pages_highmem += preallocate_image_highmem(alloc - size); 1870 pages += pages_highmem + size; 1871 } 1872 1873 /* 1874 * We only need as many page frames for the image as there are saveable 1875 * pages in memory, but we have allocated more. Release the excessive 1876 * ones now. 1877 */ 1878 pages -= free_unnecessary_pages(); 1879 1880 out: 1881 stop = ktime_get(); 1882 pr_info("Allocated %lu pages for snapshot\n", pages); 1883 swsusp_show_speed(start, stop, pages, "Allocated"); 1884 1885 return 0; 1886 1887 err_out: 1888 swsusp_free(); 1889 return -ENOMEM; 1890 } 1891 1892 #ifdef CONFIG_HIGHMEM 1893 /** 1894 * count_pages_for_highmem - Count non-highmem pages needed for copying highmem. 1895 * 1896 * Compute the number of non-highmem pages that will be necessary for creating 1897 * copies of highmem pages. 1898 */ 1899 static unsigned int count_pages_for_highmem(unsigned int nr_highmem) 1900 { 1901 unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem; 1902 1903 if (free_highmem >= nr_highmem) 1904 nr_highmem = 0; 1905 else 1906 nr_highmem -= free_highmem; 1907 1908 return nr_highmem; 1909 } 1910 #else 1911 static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; } 1912 #endif /* CONFIG_HIGHMEM */ 1913 1914 /** 1915 * enough_free_mem - Check if there is enough free memory for the image. 1916 */ 1917 static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem) 1918 { 1919 struct zone *zone; 1920 unsigned int free = alloc_normal; 1921 1922 for_each_populated_zone(zone) 1923 if (!is_highmem(zone)) 1924 free += zone_page_state(zone, NR_FREE_PAGES); 1925 1926 nr_pages += count_pages_for_highmem(nr_highmem); 1927 pr_debug("Normal pages needed: %u + %u, available pages: %u\n", 1928 nr_pages, PAGES_FOR_IO, free); 1929 1930 return free > nr_pages + PAGES_FOR_IO; 1931 } 1932 1933 #ifdef CONFIG_HIGHMEM 1934 /** 1935 * get_highmem_buffer - Allocate a buffer for highmem pages. 1936 * 1937 * If there are some highmem pages in the hibernation image, we may need a 1938 * buffer to copy them and/or load their data. 1939 */ 1940 static inline int get_highmem_buffer(int safe_needed) 1941 { 1942 buffer = get_image_page(GFP_ATOMIC, safe_needed); 1943 return buffer ? 0 : -ENOMEM; 1944 } 1945 1946 /** 1947 * alloc_highmem_image_pages - Allocate some highmem pages for the image. 1948 * 1949 * Try to allocate as many pages as needed, but if the number of free highmem 1950 * pages is less than that, allocate them all. 1951 */ 1952 static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, 1953 unsigned int nr_highmem) 1954 { 1955 unsigned int to_alloc = count_free_highmem_pages(); 1956 1957 if (to_alloc > nr_highmem) 1958 to_alloc = nr_highmem; 1959 1960 nr_highmem -= to_alloc; 1961 while (to_alloc-- > 0) { 1962 struct page *page; 1963 1964 page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM); 1965 memory_bm_set_bit(bm, page_to_pfn(page)); 1966 } 1967 return nr_highmem; 1968 } 1969 #else 1970 static inline int get_highmem_buffer(int safe_needed) { return 0; } 1971 1972 static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm, 1973 unsigned int n) { return 0; } 1974 #endif /* CONFIG_HIGHMEM */ 1975 1976 /** 1977 * swsusp_alloc - Allocate memory for hibernation image. 1978 * 1979 * We first try to allocate as many highmem pages as there are 1980 * saveable highmem pages in the system. If that fails, we allocate 1981 * non-highmem pages for the copies of the remaining highmem ones. 1982 * 1983 * In this approach it is likely that the copies of highmem pages will 1984 * also be located in the high memory, because of the way in which 1985 * copy_data_pages() works. 1986 */ 1987 static int swsusp_alloc(struct memory_bitmap *copy_bm, 1988 unsigned int nr_pages, unsigned int nr_highmem) 1989 { 1990 if (nr_highmem > 0) { 1991 if (get_highmem_buffer(PG_ANY)) 1992 goto err_out; 1993 if (nr_highmem > alloc_highmem) { 1994 nr_highmem -= alloc_highmem; 1995 nr_pages += alloc_highmem_pages(copy_bm, nr_highmem); 1996 } 1997 } 1998 if (nr_pages > alloc_normal) { 1999 nr_pages -= alloc_normal; 2000 while (nr_pages-- > 0) { 2001 struct page *page; 2002 2003 page = alloc_image_page(GFP_ATOMIC); 2004 if (!page) 2005 goto err_out; 2006 memory_bm_set_bit(copy_bm, page_to_pfn(page)); 2007 } 2008 } 2009 2010 return 0; 2011 2012 err_out: 2013 swsusp_free(); 2014 return -ENOMEM; 2015 } 2016 2017 asmlinkage __visible int swsusp_save(void) 2018 { 2019 unsigned int nr_pages, nr_highmem; 2020 2021 pr_info("Creating image:\n"); 2022 2023 drain_local_pages(NULL); 2024 nr_pages = count_data_pages(); 2025 nr_highmem = count_highmem_pages(); 2026 pr_info("Need to copy %u pages\n", nr_pages + nr_highmem); 2027 2028 if (!enough_free_mem(nr_pages, nr_highmem)) { 2029 pr_err("Not enough free memory\n"); 2030 return -ENOMEM; 2031 } 2032 2033 if (swsusp_alloc(©_bm, nr_pages, nr_highmem)) { 2034 pr_err("Memory allocation failed\n"); 2035 return -ENOMEM; 2036 } 2037 2038 /* 2039 * During allocating of suspend pagedir, new cold pages may appear. 2040 * Kill them. 2041 */ 2042 drain_local_pages(NULL); 2043 copy_data_pages(©_bm, &orig_bm); 2044 2045 /* 2046 * End of critical section. From now on, we can write to memory, 2047 * but we should not touch disk. This specially means we must _not_ 2048 * touch swap space! Except we must write out our image of course. 2049 */ 2050 2051 nr_pages += nr_highmem; 2052 nr_copy_pages = nr_pages; 2053 nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE); 2054 2055 pr_info("Image created (%d pages copied)\n", nr_pages); 2056 2057 return 0; 2058 } 2059 2060 #ifndef CONFIG_ARCH_HIBERNATION_HEADER 2061 static int init_header_complete(struct swsusp_info *info) 2062 { 2063 memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname)); 2064 info->version_code = LINUX_VERSION_CODE; 2065 return 0; 2066 } 2067 2068 static const char *check_image_kernel(struct swsusp_info *info) 2069 { 2070 if (info->version_code != LINUX_VERSION_CODE) 2071 return "kernel version"; 2072 if (strcmp(info->uts.sysname,init_utsname()->sysname)) 2073 return "system type"; 2074 if (strcmp(info->uts.release,init_utsname()->release)) 2075 return "kernel release"; 2076 if (strcmp(info->uts.version,init_utsname()->version)) 2077 return "version"; 2078 if (strcmp(info->uts.machine,init_utsname()->machine)) 2079 return "machine"; 2080 return NULL; 2081 } 2082 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */ 2083 2084 unsigned long snapshot_get_image_size(void) 2085 { 2086 return nr_copy_pages + nr_meta_pages + 1; 2087 } 2088 2089 static int init_header(struct swsusp_info *info) 2090 { 2091 memset(info, 0, sizeof(struct swsusp_info)); 2092 info->num_physpages = get_num_physpages(); 2093 info->image_pages = nr_copy_pages; 2094 info->pages = snapshot_get_image_size(); 2095 info->size = info->pages; 2096 info->size <<= PAGE_SHIFT; 2097 return init_header_complete(info); 2098 } 2099 2100 /** 2101 * pack_pfns - Prepare PFNs for saving. 2102 * @bm: Memory bitmap. 2103 * @buf: Memory buffer to store the PFNs in. 2104 * 2105 * PFNs corresponding to set bits in @bm are stored in the area of memory 2106 * pointed to by @buf (1 page at a time). 2107 */ 2108 static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm) 2109 { 2110 int j; 2111 2112 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) { 2113 buf[j] = memory_bm_next_pfn(bm); 2114 if (unlikely(buf[j] == BM_END_OF_MAP)) 2115 break; 2116 } 2117 } 2118 2119 /** 2120 * snapshot_read_next - Get the address to read the next image page from. 2121 * @handle: Snapshot handle to be used for the reading. 2122 * 2123 * On the first call, @handle should point to a zeroed snapshot_handle 2124 * structure. The structure gets populated then and a pointer to it should be 2125 * passed to this function every next time. 2126 * 2127 * On success, the function returns a positive number. Then, the caller 2128 * is allowed to read up to the returned number of bytes from the memory 2129 * location computed by the data_of() macro. 2130 * 2131 * The function returns 0 to indicate the end of the data stream condition, 2132 * and negative numbers are returned on errors. If that happens, the structure 2133 * pointed to by @handle is not updated and should not be used any more. 2134 */ 2135 int snapshot_read_next(struct snapshot_handle *handle) 2136 { 2137 if (handle->cur > nr_meta_pages + nr_copy_pages) 2138 return 0; 2139 2140 if (!buffer) { 2141 /* This makes the buffer be freed by swsusp_free() */ 2142 buffer = get_image_page(GFP_ATOMIC, PG_ANY); 2143 if (!buffer) 2144 return -ENOMEM; 2145 } 2146 if (!handle->cur) { 2147 int error; 2148 2149 error = init_header((struct swsusp_info *)buffer); 2150 if (error) 2151 return error; 2152 handle->buffer = buffer; 2153 memory_bm_position_reset(&orig_bm); 2154 memory_bm_position_reset(©_bm); 2155 } else if (handle->cur <= nr_meta_pages) { 2156 clear_page(buffer); 2157 pack_pfns(buffer, &orig_bm); 2158 } else { 2159 struct page *page; 2160 2161 page = pfn_to_page(memory_bm_next_pfn(©_bm)); 2162 if (PageHighMem(page)) { 2163 /* 2164 * Highmem pages are copied to the buffer, 2165 * because we can't return with a kmapped 2166 * highmem page (we may not be called again). 2167 */ 2168 void *kaddr; 2169 2170 kaddr = kmap_atomic(page); 2171 copy_page(buffer, kaddr); 2172 kunmap_atomic(kaddr); 2173 handle->buffer = buffer; 2174 } else { 2175 handle->buffer = page_address(page); 2176 } 2177 } 2178 handle->cur++; 2179 return PAGE_SIZE; 2180 } 2181 2182 static void duplicate_memory_bitmap(struct memory_bitmap *dst, 2183 struct memory_bitmap *src) 2184 { 2185 unsigned long pfn; 2186 2187 memory_bm_position_reset(src); 2188 pfn = memory_bm_next_pfn(src); 2189 while (pfn != BM_END_OF_MAP) { 2190 memory_bm_set_bit(dst, pfn); 2191 pfn = memory_bm_next_pfn(src); 2192 } 2193 } 2194 2195 /** 2196 * mark_unsafe_pages - Mark pages that were used before hibernation. 2197 * 2198 * Mark the pages that cannot be used for storing the image during restoration, 2199 * because they conflict with the pages that had been used before hibernation. 2200 */ 2201 static void mark_unsafe_pages(struct memory_bitmap *bm) 2202 { 2203 unsigned long pfn; 2204 2205 /* Clear the "free"/"unsafe" bit for all PFNs */ 2206 memory_bm_position_reset(free_pages_map); 2207 pfn = memory_bm_next_pfn(free_pages_map); 2208 while (pfn != BM_END_OF_MAP) { 2209 memory_bm_clear_current(free_pages_map); 2210 pfn = memory_bm_next_pfn(free_pages_map); 2211 } 2212 2213 /* Mark pages that correspond to the "original" PFNs as "unsafe" */ 2214 duplicate_memory_bitmap(free_pages_map, bm); 2215 2216 allocated_unsafe_pages = 0; 2217 } 2218 2219 static int check_header(struct swsusp_info *info) 2220 { 2221 const char *reason; 2222 2223 reason = check_image_kernel(info); 2224 if (!reason && info->num_physpages != get_num_physpages()) 2225 reason = "memory size"; 2226 if (reason) { 2227 pr_err("Image mismatch: %s\n", reason); 2228 return -EPERM; 2229 } 2230 return 0; 2231 } 2232 2233 /** 2234 * load header - Check the image header and copy the data from it. 2235 */ 2236 static int load_header(struct swsusp_info *info) 2237 { 2238 int error; 2239 2240 restore_pblist = NULL; 2241 error = check_header(info); 2242 if (!error) { 2243 nr_copy_pages = info->image_pages; 2244 nr_meta_pages = info->pages - info->image_pages - 1; 2245 } 2246 return error; 2247 } 2248 2249 /** 2250 * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap. 2251 * @bm: Memory bitmap. 2252 * @buf: Area of memory containing the PFNs. 2253 * 2254 * For each element of the array pointed to by @buf (1 page at a time), set the 2255 * corresponding bit in @bm. 2256 */ 2257 static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm) 2258 { 2259 int j; 2260 2261 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) { 2262 if (unlikely(buf[j] == BM_END_OF_MAP)) 2263 break; 2264 2265 if (pfn_valid(buf[j]) && memory_bm_pfn_present(bm, buf[j])) 2266 memory_bm_set_bit(bm, buf[j]); 2267 else 2268 return -EFAULT; 2269 } 2270 2271 return 0; 2272 } 2273 2274 #ifdef CONFIG_HIGHMEM 2275 /* 2276 * struct highmem_pbe is used for creating the list of highmem pages that 2277 * should be restored atomically during the resume from disk, because the page 2278 * frames they have occupied before the suspend are in use. 2279 */ 2280 struct highmem_pbe { 2281 struct page *copy_page; /* data is here now */ 2282 struct page *orig_page; /* data was here before the suspend */ 2283 struct highmem_pbe *next; 2284 }; 2285 2286 /* 2287 * List of highmem PBEs needed for restoring the highmem pages that were 2288 * allocated before the suspend and included in the suspend image, but have 2289 * also been allocated by the "resume" kernel, so their contents cannot be 2290 * written directly to their "original" page frames. 2291 */ 2292 static struct highmem_pbe *highmem_pblist; 2293 2294 /** 2295 * count_highmem_image_pages - Compute the number of highmem pages in the image. 2296 * @bm: Memory bitmap. 2297 * 2298 * The bits in @bm that correspond to image pages are assumed to be set. 2299 */ 2300 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) 2301 { 2302 unsigned long pfn; 2303 unsigned int cnt = 0; 2304 2305 memory_bm_position_reset(bm); 2306 pfn = memory_bm_next_pfn(bm); 2307 while (pfn != BM_END_OF_MAP) { 2308 if (PageHighMem(pfn_to_page(pfn))) 2309 cnt++; 2310 2311 pfn = memory_bm_next_pfn(bm); 2312 } 2313 return cnt; 2314 } 2315 2316 static unsigned int safe_highmem_pages; 2317 2318 static struct memory_bitmap *safe_highmem_bm; 2319 2320 /** 2321 * prepare_highmem_image - Allocate memory for loading highmem data from image. 2322 * @bm: Pointer to an uninitialized memory bitmap structure. 2323 * @nr_highmem_p: Pointer to the number of highmem image pages. 2324 * 2325 * Try to allocate as many highmem pages as there are highmem image pages 2326 * (@nr_highmem_p points to the variable containing the number of highmem image 2327 * pages). The pages that are "safe" (ie. will not be overwritten when the 2328 * hibernation image is restored entirely) have the corresponding bits set in 2329 * @bm (it must be unitialized). 2330 * 2331 * NOTE: This function should not be called if there are no highmem image pages. 2332 */ 2333 static int prepare_highmem_image(struct memory_bitmap *bm, 2334 unsigned int *nr_highmem_p) 2335 { 2336 unsigned int to_alloc; 2337 2338 if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE)) 2339 return -ENOMEM; 2340 2341 if (get_highmem_buffer(PG_SAFE)) 2342 return -ENOMEM; 2343 2344 to_alloc = count_free_highmem_pages(); 2345 if (to_alloc > *nr_highmem_p) 2346 to_alloc = *nr_highmem_p; 2347 else 2348 *nr_highmem_p = to_alloc; 2349 2350 safe_highmem_pages = 0; 2351 while (to_alloc-- > 0) { 2352 struct page *page; 2353 2354 page = alloc_page(__GFP_HIGHMEM); 2355 if (!swsusp_page_is_free(page)) { 2356 /* The page is "safe", set its bit the bitmap */ 2357 memory_bm_set_bit(bm, page_to_pfn(page)); 2358 safe_highmem_pages++; 2359 } 2360 /* Mark the page as allocated */ 2361 swsusp_set_page_forbidden(page); 2362 swsusp_set_page_free(page); 2363 } 2364 memory_bm_position_reset(bm); 2365 safe_highmem_bm = bm; 2366 return 0; 2367 } 2368 2369 static struct page *last_highmem_page; 2370 2371 /** 2372 * get_highmem_page_buffer - Prepare a buffer to store a highmem image page. 2373 * 2374 * For a given highmem image page get a buffer that suspend_write_next() should 2375 * return to its caller to write to. 2376 * 2377 * If the page is to be saved to its "original" page frame or a copy of 2378 * the page is to be made in the highmem, @buffer is returned. Otherwise, 2379 * the copy of the page is to be made in normal memory, so the address of 2380 * the copy is returned. 2381 * 2382 * If @buffer is returned, the caller of suspend_write_next() will write 2383 * the page's contents to @buffer, so they will have to be copied to the 2384 * right location on the next call to suspend_write_next() and it is done 2385 * with the help of copy_last_highmem_page(). For this purpose, if 2386 * @buffer is returned, @last_highmem_page is set to the page to which 2387 * the data will have to be copied from @buffer. 2388 */ 2389 static void *get_highmem_page_buffer(struct page *page, 2390 struct chain_allocator *ca) 2391 { 2392 struct highmem_pbe *pbe; 2393 void *kaddr; 2394 2395 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) { 2396 /* 2397 * We have allocated the "original" page frame and we can 2398 * use it directly to store the loaded page. 2399 */ 2400 last_highmem_page = page; 2401 return buffer; 2402 } 2403 /* 2404 * The "original" page frame has not been allocated and we have to 2405 * use a "safe" page frame to store the loaded page. 2406 */ 2407 pbe = chain_alloc(ca, sizeof(struct highmem_pbe)); 2408 if (!pbe) { 2409 swsusp_free(); 2410 return ERR_PTR(-ENOMEM); 2411 } 2412 pbe->orig_page = page; 2413 if (safe_highmem_pages > 0) { 2414 struct page *tmp; 2415 2416 /* Copy of the page will be stored in high memory */ 2417 kaddr = buffer; 2418 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm)); 2419 safe_highmem_pages--; 2420 last_highmem_page = tmp; 2421 pbe->copy_page = tmp; 2422 } else { 2423 /* Copy of the page will be stored in normal memory */ 2424 kaddr = safe_pages_list; 2425 safe_pages_list = safe_pages_list->next; 2426 pbe->copy_page = virt_to_page(kaddr); 2427 } 2428 pbe->next = highmem_pblist; 2429 highmem_pblist = pbe; 2430 return kaddr; 2431 } 2432 2433 /** 2434 * copy_last_highmem_page - Copy most the most recent highmem image page. 2435 * 2436 * Copy the contents of a highmem image from @buffer, where the caller of 2437 * snapshot_write_next() has stored them, to the right location represented by 2438 * @last_highmem_page . 2439 */ 2440 static void copy_last_highmem_page(void) 2441 { 2442 if (last_highmem_page) { 2443 void *dst; 2444 2445 dst = kmap_atomic(last_highmem_page); 2446 copy_page(dst, buffer); 2447 kunmap_atomic(dst); 2448 last_highmem_page = NULL; 2449 } 2450 } 2451 2452 static inline int last_highmem_page_copied(void) 2453 { 2454 return !last_highmem_page; 2455 } 2456 2457 static inline void free_highmem_data(void) 2458 { 2459 if (safe_highmem_bm) 2460 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR); 2461 2462 if (buffer) 2463 free_image_page(buffer, PG_UNSAFE_CLEAR); 2464 } 2465 #else 2466 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; } 2467 2468 static inline int prepare_highmem_image(struct memory_bitmap *bm, 2469 unsigned int *nr_highmem_p) { return 0; } 2470 2471 static inline void *get_highmem_page_buffer(struct page *page, 2472 struct chain_allocator *ca) 2473 { 2474 return ERR_PTR(-EINVAL); 2475 } 2476 2477 static inline void copy_last_highmem_page(void) {} 2478 static inline int last_highmem_page_copied(void) { return 1; } 2479 static inline void free_highmem_data(void) {} 2480 #endif /* CONFIG_HIGHMEM */ 2481 2482 #define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe)) 2483 2484 /** 2485 * prepare_image - Make room for loading hibernation image. 2486 * @new_bm: Unitialized memory bitmap structure. 2487 * @bm: Memory bitmap with unsafe pages marked. 2488 * 2489 * Use @bm to mark the pages that will be overwritten in the process of 2490 * restoring the system memory state from the suspend image ("unsafe" pages) 2491 * and allocate memory for the image. 2492 * 2493 * The idea is to allocate a new memory bitmap first and then allocate 2494 * as many pages as needed for image data, but without specifying what those 2495 * pages will be used for just yet. Instead, we mark them all as allocated and 2496 * create a lists of "safe" pages to be used later. On systems with high 2497 * memory a list of "safe" highmem pages is created too. 2498 */ 2499 static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm) 2500 { 2501 unsigned int nr_pages, nr_highmem; 2502 struct linked_page *lp; 2503 int error; 2504 2505 /* If there is no highmem, the buffer will not be necessary */ 2506 free_image_page(buffer, PG_UNSAFE_CLEAR); 2507 buffer = NULL; 2508 2509 nr_highmem = count_highmem_image_pages(bm); 2510 mark_unsafe_pages(bm); 2511 2512 error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE); 2513 if (error) 2514 goto Free; 2515 2516 duplicate_memory_bitmap(new_bm, bm); 2517 memory_bm_free(bm, PG_UNSAFE_KEEP); 2518 if (nr_highmem > 0) { 2519 error = prepare_highmem_image(bm, &nr_highmem); 2520 if (error) 2521 goto Free; 2522 } 2523 /* 2524 * Reserve some safe pages for potential later use. 2525 * 2526 * NOTE: This way we make sure there will be enough safe pages for the 2527 * chain_alloc() in get_buffer(). It is a bit wasteful, but 2528 * nr_copy_pages cannot be greater than 50% of the memory anyway. 2529 * 2530 * nr_copy_pages cannot be less than allocated_unsafe_pages too. 2531 */ 2532 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages; 2533 nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE); 2534 while (nr_pages > 0) { 2535 lp = get_image_page(GFP_ATOMIC, PG_SAFE); 2536 if (!lp) { 2537 error = -ENOMEM; 2538 goto Free; 2539 } 2540 lp->next = safe_pages_list; 2541 safe_pages_list = lp; 2542 nr_pages--; 2543 } 2544 /* Preallocate memory for the image */ 2545 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages; 2546 while (nr_pages > 0) { 2547 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC); 2548 if (!lp) { 2549 error = -ENOMEM; 2550 goto Free; 2551 } 2552 if (!swsusp_page_is_free(virt_to_page(lp))) { 2553 /* The page is "safe", add it to the list */ 2554 lp->next = safe_pages_list; 2555 safe_pages_list = lp; 2556 } 2557 /* Mark the page as allocated */ 2558 swsusp_set_page_forbidden(virt_to_page(lp)); 2559 swsusp_set_page_free(virt_to_page(lp)); 2560 nr_pages--; 2561 } 2562 return 0; 2563 2564 Free: 2565 swsusp_free(); 2566 return error; 2567 } 2568 2569 /** 2570 * get_buffer - Get the address to store the next image data page. 2571 * 2572 * Get the address that snapshot_write_next() should return to its caller to 2573 * write to. 2574 */ 2575 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca) 2576 { 2577 struct pbe *pbe; 2578 struct page *page; 2579 unsigned long pfn = memory_bm_next_pfn(bm); 2580 2581 if (pfn == BM_END_OF_MAP) 2582 return ERR_PTR(-EFAULT); 2583 2584 page = pfn_to_page(pfn); 2585 if (PageHighMem(page)) 2586 return get_highmem_page_buffer(page, ca); 2587 2588 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) 2589 /* 2590 * We have allocated the "original" page frame and we can 2591 * use it directly to store the loaded page. 2592 */ 2593 return page_address(page); 2594 2595 /* 2596 * The "original" page frame has not been allocated and we have to 2597 * use a "safe" page frame to store the loaded page. 2598 */ 2599 pbe = chain_alloc(ca, sizeof(struct pbe)); 2600 if (!pbe) { 2601 swsusp_free(); 2602 return ERR_PTR(-ENOMEM); 2603 } 2604 pbe->orig_address = page_address(page); 2605 pbe->address = safe_pages_list; 2606 safe_pages_list = safe_pages_list->next; 2607 pbe->next = restore_pblist; 2608 restore_pblist = pbe; 2609 return pbe->address; 2610 } 2611 2612 /** 2613 * snapshot_write_next - Get the address to store the next image page. 2614 * @handle: Snapshot handle structure to guide the writing. 2615 * 2616 * On the first call, @handle should point to a zeroed snapshot_handle 2617 * structure. The structure gets populated then and a pointer to it should be 2618 * passed to this function every next time. 2619 * 2620 * On success, the function returns a positive number. Then, the caller 2621 * is allowed to write up to the returned number of bytes to the memory 2622 * location computed by the data_of() macro. 2623 * 2624 * The function returns 0 to indicate the "end of file" condition. Negative 2625 * numbers are returned on errors, in which cases the structure pointed to by 2626 * @handle is not updated and should not be used any more. 2627 */ 2628 int snapshot_write_next(struct snapshot_handle *handle) 2629 { 2630 static struct chain_allocator ca; 2631 int error = 0; 2632 2633 /* Check if we have already loaded the entire image */ 2634 if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) 2635 return 0; 2636 2637 handle->sync_read = 1; 2638 2639 if (!handle->cur) { 2640 if (!buffer) 2641 /* This makes the buffer be freed by swsusp_free() */ 2642 buffer = get_image_page(GFP_ATOMIC, PG_ANY); 2643 2644 if (!buffer) 2645 return -ENOMEM; 2646 2647 handle->buffer = buffer; 2648 } else if (handle->cur == 1) { 2649 error = load_header(buffer); 2650 if (error) 2651 return error; 2652 2653 safe_pages_list = NULL; 2654 2655 error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY); 2656 if (error) 2657 return error; 2658 2659 hibernate_restore_protection_begin(); 2660 } else if (handle->cur <= nr_meta_pages + 1) { 2661 error = unpack_orig_pfns(buffer, ©_bm); 2662 if (error) 2663 return error; 2664 2665 if (handle->cur == nr_meta_pages + 1) { 2666 error = prepare_image(&orig_bm, ©_bm); 2667 if (error) 2668 return error; 2669 2670 chain_init(&ca, GFP_ATOMIC, PG_SAFE); 2671 memory_bm_position_reset(&orig_bm); 2672 restore_pblist = NULL; 2673 handle->buffer = get_buffer(&orig_bm, &ca); 2674 handle->sync_read = 0; 2675 if (IS_ERR(handle->buffer)) 2676 return PTR_ERR(handle->buffer); 2677 } 2678 } else { 2679 copy_last_highmem_page(); 2680 hibernate_restore_protect_page(handle->buffer); 2681 handle->buffer = get_buffer(&orig_bm, &ca); 2682 if (IS_ERR(handle->buffer)) 2683 return PTR_ERR(handle->buffer); 2684 if (handle->buffer != buffer) 2685 handle->sync_read = 0; 2686 } 2687 handle->cur++; 2688 return PAGE_SIZE; 2689 } 2690 2691 /** 2692 * snapshot_write_finalize - Complete the loading of a hibernation image. 2693 * 2694 * Must be called after the last call to snapshot_write_next() in case the last 2695 * page in the image happens to be a highmem page and its contents should be 2696 * stored in highmem. Additionally, it recycles bitmap memory that's not 2697 * necessary any more. 2698 */ 2699 void snapshot_write_finalize(struct snapshot_handle *handle) 2700 { 2701 copy_last_highmem_page(); 2702 hibernate_restore_protect_page(handle->buffer); 2703 /* Do that only if we have loaded the image entirely */ 2704 if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) { 2705 memory_bm_recycle(&orig_bm); 2706 free_highmem_data(); 2707 } 2708 } 2709 2710 int snapshot_image_loaded(struct snapshot_handle *handle) 2711 { 2712 return !(!nr_copy_pages || !last_highmem_page_copied() || 2713 handle->cur <= nr_meta_pages + nr_copy_pages); 2714 } 2715 2716 #ifdef CONFIG_HIGHMEM 2717 /* Assumes that @buf is ready and points to a "safe" page */ 2718 static inline void swap_two_pages_data(struct page *p1, struct page *p2, 2719 void *buf) 2720 { 2721 void *kaddr1, *kaddr2; 2722 2723 kaddr1 = kmap_atomic(p1); 2724 kaddr2 = kmap_atomic(p2); 2725 copy_page(buf, kaddr1); 2726 copy_page(kaddr1, kaddr2); 2727 copy_page(kaddr2, buf); 2728 kunmap_atomic(kaddr2); 2729 kunmap_atomic(kaddr1); 2730 } 2731 2732 /** 2733 * restore_highmem - Put highmem image pages into their original locations. 2734 * 2735 * For each highmem page that was in use before hibernation and is included in 2736 * the image, and also has been allocated by the "restore" kernel, swap its 2737 * current contents with the previous (ie. "before hibernation") ones. 2738 * 2739 * If the restore eventually fails, we can call this function once again and 2740 * restore the highmem state as seen by the restore kernel. 2741 */ 2742 int restore_highmem(void) 2743 { 2744 struct highmem_pbe *pbe = highmem_pblist; 2745 void *buf; 2746 2747 if (!pbe) 2748 return 0; 2749 2750 buf = get_image_page(GFP_ATOMIC, PG_SAFE); 2751 if (!buf) 2752 return -ENOMEM; 2753 2754 while (pbe) { 2755 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf); 2756 pbe = pbe->next; 2757 } 2758 free_image_page(buf, PG_UNSAFE_CLEAR); 2759 return 0; 2760 } 2761 #endif /* CONFIG_HIGHMEM */ 2762