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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)
43static bool hibernate_restore_protection;
44static bool hibernate_restore_protection_active;
45
46void enable_restore_image_protection(void)
47{
48 hibernate_restore_protection = true;
49}
50
51static inline void hibernate_restore_protection_begin(void)
52{
53 hibernate_restore_protection_active = hibernate_restore_protection;
54}
55
56static inline void hibernate_restore_protection_end(void)
57{
58 hibernate_restore_protection_active = false;
59}
60
61static 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
67static 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
73static inline void hibernate_restore_protection_begin(void) {}
74static inline void hibernate_restore_protection_end(void) {}
75static inline void hibernate_restore_protect_page(void *page_address) {}
76static inline void hibernate_restore_unprotect_page(void *page_address) {}
77#endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */
78
79static int swsusp_page_is_free(struct page *);
80static void swsusp_set_page_forbidden(struct page *);
81static void swsusp_unset_page_forbidden(struct page *);
82
83/*
84 * Number of bytes to reserve for memory allocations made by device drivers
85 * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
86 * cause image creation to fail (tunable via /sys/power/reserved_size).
87 */
88unsigned long reserved_size;
89
90void __init hibernate_reserved_size_init(void)
91{
92 reserved_size = SPARE_PAGES * PAGE_SIZE;
93}
94
95/*
96 * Preferred image size in bytes (tunable via /sys/power/image_size).
97 * When it is set to N, swsusp will do its best to ensure the image
98 * size will not exceed N bytes, but if that is impossible, it will
99 * try to create the smallest image possible.
100 */
101unsigned long image_size;
102
103void __init hibernate_image_size_init(void)
104{
105 image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
106}
107
108/*
109 * List of PBEs needed for restoring the pages that were allocated before
110 * the suspend and included in the suspend image, but have also been
111 * allocated by the "resume" kernel, so their contents cannot be written
112 * directly to their "original" page frames.
113 */
114struct pbe *restore_pblist;
115
116/* struct linked_page is used to build chains of pages */
117
118#define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *))
119
120struct linked_page {
121 struct linked_page *next;
122 char data[LINKED_PAGE_DATA_SIZE];
123} __packed;
124
125/*
126 * List of "safe" pages (ie. pages that were not used by the image kernel
127 * before hibernation) that may be used as temporary storage for image kernel
128 * memory contents.
129 */
130static struct linked_page *safe_pages_list;
131
132/* Pointer to an auxiliary buffer (1 page) */
133static void *buffer;
134
135#define PG_ANY 0
136#define PG_SAFE 1
137#define PG_UNSAFE_CLEAR 1
138#define PG_UNSAFE_KEEP 0
139
140static unsigned int allocated_unsafe_pages;
141
142/**
143 * get_image_page - Allocate a page for a hibernation image.
144 * @gfp_mask: GFP mask for the allocation.
145 * @safe_needed: Get pages that were not used before hibernation (restore only)
146 *
147 * During image restoration, for storing the PBE list and the image data, we can
148 * only use memory pages that do not conflict with the pages used before
149 * hibernation. The "unsafe" pages have PageNosaveFree set and we count them
150 * using allocated_unsafe_pages.
151 *
152 * Each allocated image page is marked as PageNosave and PageNosaveFree so that
153 * swsusp_free() can release it.
154 */
155static void *get_image_page(gfp_t gfp_mask, int safe_needed)
156{
157 void *res;
158
159 res = (void *)get_zeroed_page(gfp_mask);
160 if (safe_needed)
161 while (res && swsusp_page_is_free(virt_to_page(res))) {
162 /* The page is unsafe, mark it for swsusp_free() */
163 swsusp_set_page_forbidden(virt_to_page(res));
164 allocated_unsafe_pages++;
165 res = (void *)get_zeroed_page(gfp_mask);
166 }
167 if (res) {
168 swsusp_set_page_forbidden(virt_to_page(res));
169 swsusp_set_page_free(virt_to_page(res));
170 }
171 return res;
172}
173
174static void *__get_safe_page(gfp_t gfp_mask)
175{
176 if (safe_pages_list) {
177 void *ret = safe_pages_list;
178
179 safe_pages_list = safe_pages_list->next;
180 memset(ret, 0, PAGE_SIZE);
181 return ret;
182 }
183 return get_image_page(gfp_mask, PG_SAFE);
184}
185
186unsigned long get_safe_page(gfp_t gfp_mask)
187{
188 return (unsigned long)__get_safe_page(gfp_mask);
189}
190
191static struct page *alloc_image_page(gfp_t gfp_mask)
192{
193 struct page *page;
194
195 page = alloc_page(gfp_mask);
196 if (page) {
197 swsusp_set_page_forbidden(page);
198 swsusp_set_page_free(page);
199 }
200 return page;
201}
202
203static void recycle_safe_page(void *page_address)
204{
205 struct linked_page *lp = page_address;
206
207 lp->next = safe_pages_list;
208 safe_pages_list = lp;
209}
210
211/**
212 * free_image_page - Free a page allocated for hibernation image.
213 * @addr: Address of the page to free.
214 * @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
215 *
216 * The page to free should have been allocated by get_image_page() (page flags
217 * set by it are affected).
218 */
219static inline void free_image_page(void *addr, int clear_nosave_free)
220{
221 struct page *page;
222
223 BUG_ON(!virt_addr_valid(addr));
224
225 page = virt_to_page(addr);
226
227 swsusp_unset_page_forbidden(page);
228 if (clear_nosave_free)
229 swsusp_unset_page_free(page);
230
231 __free_page(page);
232}
233
234static inline void free_list_of_pages(struct linked_page *list,
235 int clear_page_nosave)
236{
237 while (list) {
238 struct linked_page *lp = list->next;
239
240 free_image_page(list, clear_page_nosave);
241 list = lp;
242 }
243}
244
245/*
246 * struct chain_allocator is used for allocating small objects out of
247 * a linked list of pages called 'the chain'.
248 *
249 * The chain grows each time when there is no room for a new object in
250 * the current page. The allocated objects cannot be freed individually.
251 * It is only possible to free them all at once, by freeing the entire
252 * chain.
253 *
254 * NOTE: The chain allocator may be inefficient if the allocated objects
255 * are not much smaller than PAGE_SIZE.
256 */
257struct chain_allocator {
258 struct linked_page *chain; /* the chain */
259 unsigned int used_space; /* total size of objects allocated out
260 of the current page */
261 gfp_t gfp_mask; /* mask for allocating pages */
262 int safe_needed; /* if set, only "safe" pages are allocated */
263};
264
265static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask,
266 int safe_needed)
267{
268 ca->chain = NULL;
269 ca->used_space = LINKED_PAGE_DATA_SIZE;
270 ca->gfp_mask = gfp_mask;
271 ca->safe_needed = safe_needed;
272}
273
274static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
275{
276 void *ret;
277
278 if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
279 struct linked_page *lp;
280
281 lp = ca->safe_needed ? __get_safe_page(ca->gfp_mask) :
282 get_image_page(ca->gfp_mask, PG_ANY);
283 if (!lp)
284 return NULL;
285
286 lp->next = ca->chain;
287 ca->chain = lp;
288 ca->used_space = 0;
289 }
290 ret = ca->chain->data + ca->used_space;
291 ca->used_space += size;
292 return ret;
293}
294
295/**
296 * Data types related to memory bitmaps.
297 *
298 * Memory bitmap is a structure consiting of many linked lists of
299 * objects. The main list's elements are of type struct zone_bitmap
300 * and each of them corresonds to one zone. For each zone bitmap
301 * object there is a list of objects of type struct bm_block that
302 * represent each blocks of bitmap in which information is stored.
303 *
304 * struct memory_bitmap contains a pointer to the main list of zone
305 * bitmap objects, a struct bm_position used for browsing the bitmap,
306 * and a pointer to the list of pages used for allocating all of the
307 * zone bitmap objects and bitmap block objects.
308 *
309 * NOTE: It has to be possible to lay out the bitmap in memory
310 * using only allocations of order 0. Additionally, the bitmap is
311 * designed to work with arbitrary number of zones (this is over the
312 * top for now, but let's avoid making unnecessary assumptions ;-).
313 *
314 * struct zone_bitmap contains a pointer to a list of bitmap block
315 * objects and a pointer to the bitmap block object that has been
316 * most recently used for setting bits. Additionally, it contains the
317 * PFNs that correspond to the start and end of the represented zone.
318 *
319 * struct bm_block contains a pointer to the memory page in which
320 * information is stored (in the form of a block of bitmap)
321 * It also contains the pfns that correspond to the start and end of
322 * the represented memory area.
323 *
324 * The memory bitmap is organized as a radix tree to guarantee fast random
325 * access to the bits. There is one radix tree for each zone (as returned
326 * from create_mem_extents).
327 *
328 * One radix tree is represented by one struct mem_zone_bm_rtree. There are
329 * two linked lists for the nodes of the tree, one for the inner nodes and
330 * one for the leave nodes. The linked leave nodes are used for fast linear
331 * access of the memory bitmap.
332 *
333 * The struct rtree_node represents one node of the radix tree.
334 */
335
336#define BM_END_OF_MAP (~0UL)
337
338#define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE)
339#define BM_BLOCK_SHIFT (PAGE_SHIFT + 3)
340#define BM_BLOCK_MASK ((1UL << BM_BLOCK_SHIFT) - 1)
341
342/*
343 * struct rtree_node is a wrapper struct to link the nodes
344 * of the rtree together for easy linear iteration over
345 * bits and easy freeing
346 */
347struct rtree_node {
348 struct list_head list;
349 unsigned long *data;
350};
351
352/*
353 * struct mem_zone_bm_rtree represents a bitmap used for one
354 * populated memory zone.
355 */
356struct mem_zone_bm_rtree {
357 struct list_head list; /* Link Zones together */
358 struct list_head nodes; /* Radix Tree inner nodes */
359 struct list_head leaves; /* Radix Tree leaves */
360 unsigned long start_pfn; /* Zone start page frame */
361 unsigned long end_pfn; /* Zone end page frame + 1 */
362 struct rtree_node *rtree; /* Radix Tree Root */
363 int levels; /* Number of Radix Tree Levels */
364 unsigned int blocks; /* Number of Bitmap Blocks */
365};
366
367/* strcut bm_position is used for browsing memory bitmaps */
368
369struct bm_position {
370 struct mem_zone_bm_rtree *zone;
371 struct rtree_node *node;
372 unsigned long node_pfn;
373 int node_bit;
374};
375
376struct memory_bitmap {
377 struct list_head zones;
378 struct linked_page *p_list; /* list of pages used to store zone
379 bitmap objects and bitmap block
380 objects */
381 struct bm_position cur; /* most recently used bit position */
382};
383
384/* Functions that operate on memory bitmaps */
385
386#define BM_ENTRIES_PER_LEVEL (PAGE_SIZE / sizeof(unsigned long))
387#if BITS_PER_LONG == 32
388#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 2)
389#else
390#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 3)
391#endif
392#define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
393
394/**
395 * alloc_rtree_node - Allocate a new node and add it to the radix tree.
396 *
397 * This function is used to allocate inner nodes as well as the
398 * leave nodes of the radix tree. It also adds the node to the
399 * corresponding linked list passed in by the *list parameter.
400 */
401static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
402 struct chain_allocator *ca,
403 struct list_head *list)
404{
405 struct rtree_node *node;
406
407 node = chain_alloc(ca, sizeof(struct rtree_node));
408 if (!node)
409 return NULL;
410
411 node->data = get_image_page(gfp_mask, safe_needed);
412 if (!node->data)
413 return NULL;
414
415 list_add_tail(&node->list, list);
416
417 return node;
418}
419
420/**
421 * add_rtree_block - Add a new leave node to the radix tree.
422 *
423 * The leave nodes need to be allocated in order to keep the leaves
424 * linked list in order. This is guaranteed by the zone->blocks
425 * counter.
426 */
427static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
428 int safe_needed, struct chain_allocator *ca)
429{
430 struct rtree_node *node, *block, **dst;
431 unsigned int levels_needed, block_nr;
432 int i;
433
434 block_nr = zone->blocks;
435 levels_needed = 0;
436
437 /* How many levels do we need for this block nr? */
438 while (block_nr) {
439 levels_needed += 1;
440 block_nr >>= BM_RTREE_LEVEL_SHIFT;
441 }
442
443 /* Make sure the rtree has enough levels */
444 for (i = zone->levels; i < levels_needed; i++) {
445 node = alloc_rtree_node(gfp_mask, safe_needed, ca,
446 &zone->nodes);
447 if (!node)
448 return -ENOMEM;
449
450 node->data[0] = (unsigned long)zone->rtree;
451 zone->rtree = node;
452 zone->levels += 1;
453 }
454
455 /* Allocate new block */
456 block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
457 if (!block)
458 return -ENOMEM;
459
460 /* Now walk the rtree to insert the block */
461 node = zone->rtree;
462 dst = &zone->rtree;
463 block_nr = zone->blocks;
464 for (i = zone->levels; i > 0; i--) {
465 int index;
466
467 if (!node) {
468 node = alloc_rtree_node(gfp_mask, safe_needed, ca,
469 &zone->nodes);
470 if (!node)
471 return -ENOMEM;
472 *dst = node;
473 }
474
475 index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
476 index &= BM_RTREE_LEVEL_MASK;
477 dst = (struct rtree_node **)&((*dst)->data[index]);
478 node = *dst;
479 }
480
481 zone->blocks += 1;
482 *dst = block;
483
484 return 0;
485}
486
487static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
488 int clear_nosave_free);
489
490/**
491 * create_zone_bm_rtree - Create a radix tree for one zone.
492 *
493 * Allocated the mem_zone_bm_rtree structure and initializes it.
494 * This function also allocated and builds the radix tree for the
495 * zone.
496 */
497static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
498 int safe_needed,
499 struct chain_allocator *ca,
500 unsigned long start,
501 unsigned long end)
502{
503 struct mem_zone_bm_rtree *zone;
504 unsigned int i, nr_blocks;
505 unsigned long pages;
506
507 pages = end - start;
508 zone = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
509 if (!zone)
510 return NULL;
511
512 INIT_LIST_HEAD(&zone->nodes);
513 INIT_LIST_HEAD(&zone->leaves);
514 zone->start_pfn = start;
515 zone->end_pfn = end;
516 nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
517
518 for (i = 0; i < nr_blocks; i++) {
519 if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
520 free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
521 return NULL;
522 }
523 }
524
525 return zone;
526}
527
528/**
529 * free_zone_bm_rtree - Free the memory of the radix tree.
530 *
531 * Free all node pages of the radix tree. The mem_zone_bm_rtree
532 * structure itself is not freed here nor are the rtree_node
533 * structs.
534 */
535static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
536 int clear_nosave_free)
537{
538 struct rtree_node *node;
539
540 list_for_each_entry(node, &zone->nodes, list)
541 free_image_page(node->data, clear_nosave_free);
542
543 list_for_each_entry(node, &zone->leaves, list)
544 free_image_page(node->data, clear_nosave_free);
545}
546
547static void memory_bm_position_reset(struct memory_bitmap *bm)
548{
549 bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
550 list);
551 bm->cur.node = list_entry(bm->cur.zone->leaves.next,
552 struct rtree_node, list);
553 bm->cur.node_pfn = 0;
554 bm->cur.node_bit = 0;
555}
556
557static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
558
559struct mem_extent {
560 struct list_head hook;
561 unsigned long start;
562 unsigned long end;
563};
564
565/**
566 * free_mem_extents - Free a list of memory extents.
567 * @list: List of extents to free.
568 */
569static void free_mem_extents(struct list_head *list)
570{
571 struct mem_extent *ext, *aux;
572
573 list_for_each_entry_safe(ext, aux, list, hook) {
574 list_del(&ext->hook);
575 kfree(ext);
576 }
577}
578
579/**
580 * create_mem_extents - Create a list of memory extents.
581 * @list: List to put the extents into.
582 * @gfp_mask: Mask to use for memory allocations.
583 *
584 * The extents represent contiguous ranges of PFNs.
585 */
586static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
587{
588 struct zone *zone;
589
590 INIT_LIST_HEAD(list);
591
592 for_each_populated_zone(zone) {
593 unsigned long zone_start, zone_end;
594 struct mem_extent *ext, *cur, *aux;
595
596 zone_start = zone->zone_start_pfn;
597 zone_end = zone_end_pfn(zone);
598
599 list_for_each_entry(ext, list, hook)
600 if (zone_start <= ext->end)
601 break;
602
603 if (&ext->hook == list || zone_end < ext->start) {
604 /* New extent is necessary */
605 struct mem_extent *new_ext;
606
607 new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
608 if (!new_ext) {
609 free_mem_extents(list);
610 return -ENOMEM;
611 }
612 new_ext->start = zone_start;
613 new_ext->end = zone_end;
614 list_add_tail(&new_ext->hook, &ext->hook);
615 continue;
616 }
617
618 /* Merge this zone's range of PFNs with the existing one */
619 if (zone_start < ext->start)
620 ext->start = zone_start;
621 if (zone_end > ext->end)
622 ext->end = zone_end;
623
624 /* More merging may be possible */
625 cur = ext;
626 list_for_each_entry_safe_continue(cur, aux, list, hook) {
627 if (zone_end < cur->start)
628 break;
629 if (zone_end < cur->end)
630 ext->end = cur->end;
631 list_del(&cur->hook);
632 kfree(cur);
633 }
634 }
635
636 return 0;
637}
638
639/**
640 * memory_bm_create - Allocate memory for a memory bitmap.
641 */
642static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
643 int safe_needed)
644{
645 struct chain_allocator ca;
646 struct list_head mem_extents;
647 struct mem_extent *ext;
648 int error;
649
650 chain_init(&ca, gfp_mask, safe_needed);
651 INIT_LIST_HEAD(&bm->zones);
652
653 error = create_mem_extents(&mem_extents, gfp_mask);
654 if (error)
655 return error;
656
657 list_for_each_entry(ext, &mem_extents, hook) {
658 struct mem_zone_bm_rtree *zone;
659
660 zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
661 ext->start, ext->end);
662 if (!zone) {
663 error = -ENOMEM;
664 goto Error;
665 }
666 list_add_tail(&zone->list, &bm->zones);
667 }
668
669 bm->p_list = ca.chain;
670 memory_bm_position_reset(bm);
671 Exit:
672 free_mem_extents(&mem_extents);
673 return error;
674
675 Error:
676 bm->p_list = ca.chain;
677 memory_bm_free(bm, PG_UNSAFE_CLEAR);
678 goto Exit;
679}
680
681/**
682 * memory_bm_free - Free memory occupied by the memory bitmap.
683 * @bm: Memory bitmap.
684 */
685static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
686{
687 struct mem_zone_bm_rtree *zone;
688
689 list_for_each_entry(zone, &bm->zones, list)
690 free_zone_bm_rtree(zone, clear_nosave_free);
691
692 free_list_of_pages(bm->p_list, clear_nosave_free);
693
694 INIT_LIST_HEAD(&bm->zones);
695}
696
697/**
698 * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
699 *
700 * Find the bit in memory bitmap @bm that corresponds to the given PFN.
701 * The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
702 *
703 * Walk the radix tree to find the page containing the bit that represents @pfn
704 * and return the position of the bit in @addr and @bit_nr.
705 */
706static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
707 void **addr, unsigned int *bit_nr)
708{
709 struct mem_zone_bm_rtree *curr, *zone;
710 struct rtree_node *node;
711 int i, block_nr;
712
713 zone = bm->cur.zone;
714
715 if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
716 goto zone_found;
717
718 zone = NULL;
719
720 /* Find the right zone */
721 list_for_each_entry(curr, &bm->zones, list) {
722 if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
723 zone = curr;
724 break;
725 }
726 }
727
728 if (!zone)
729 return -EFAULT;
730
731zone_found:
732 /*
733 * We have found the zone. Now walk the radix tree to find the leaf node
734 * for our PFN.
735 */
736
737 /*
738 * If the zone we wish to scan is the the current zone and the
739 * pfn falls into the current node then we do not need to walk
740 * the tree.
741 */
742 node = bm->cur.node;
743 if (zone == bm->cur.zone &&
744 ((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
745 goto node_found;
746
747 node = zone->rtree;
748 block_nr = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
749
750 for (i = zone->levels; i > 0; i--) {
751 int index;
752
753 index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
754 index &= BM_RTREE_LEVEL_MASK;
755 BUG_ON(node->data[index] == 0);
756 node = (struct rtree_node *)node->data[index];
757 }
758
759node_found:
760 /* Update last position */
761 bm->cur.zone = zone;
762 bm->cur.node = node;
763 bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
764
765 /* Set return values */
766 *addr = node->data;
767 *bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
768
769 return 0;
770}
771
772static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
773{
774 void *addr;
775 unsigned int bit;
776 int error;
777
778 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
779 BUG_ON(error);
780 set_bit(bit, addr);
781}
782
783static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
784{
785 void *addr;
786 unsigned int bit;
787 int error;
788
789 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
790 if (!error)
791 set_bit(bit, addr);
792
793 return error;
794}
795
796static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
797{
798 void *addr;
799 unsigned int bit;
800 int error;
801
802 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
803 BUG_ON(error);
804 clear_bit(bit, addr);
805}
806
807static void memory_bm_clear_current(struct memory_bitmap *bm)
808{
809 int bit;
810
811 bit = max(bm->cur.node_bit - 1, 0);
812 clear_bit(bit, bm->cur.node->data);
813}
814
815static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
816{
817 void *addr;
818 unsigned int bit;
819 int error;
820
821 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
822 BUG_ON(error);
823 return test_bit(bit, addr);
824}
825
826static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
827{
828 void *addr;
829 unsigned int bit;
830
831 return !memory_bm_find_bit(bm, pfn, &addr, &bit);
832}
833
834/*
835 * rtree_next_node - Jump to the next leaf node.
836 *
837 * Set the position to the beginning of the next node in the
838 * memory bitmap. This is either the next node in the current
839 * zone's radix tree or the first node in the radix tree of the
840 * next zone.
841 *
842 * Return true if there is a next node, false otherwise.
843 */
844static bool rtree_next_node(struct memory_bitmap *bm)
845{
846 if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) {
847 bm->cur.node = list_entry(bm->cur.node->list.next,
848 struct rtree_node, list);
849 bm->cur.node_pfn += BM_BITS_PER_BLOCK;
850 bm->cur.node_bit = 0;
851 touch_softlockup_watchdog();
852 return true;
853 }
854
855 /* No more nodes, goto next zone */
856 if (!list_is_last(&bm->cur.zone->list, &bm->zones)) {
857 bm->cur.zone = list_entry(bm->cur.zone->list.next,
858 struct mem_zone_bm_rtree, list);
859 bm->cur.node = list_entry(bm->cur.zone->leaves.next,
860 struct rtree_node, list);
861 bm->cur.node_pfn = 0;
862 bm->cur.node_bit = 0;
863 return true;
864 }
865
866 /* No more zones */
867 return false;
868}
869
870/**
871 * memory_bm_rtree_next_pfn - Find the next set bit in a memory bitmap.
872 * @bm: Memory bitmap.
873 *
874 * Starting from the last returned position this function searches for the next
875 * set bit in @bm and returns the PFN represented by it. If no more bits are
876 * set, BM_END_OF_MAP is returned.
877 *
878 * It is required to run memory_bm_position_reset() before the first call to
879 * this function for the given memory bitmap.
880 */
881static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
882{
883 unsigned long bits, pfn, pages;
884 int bit;
885
886 do {
887 pages = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
888 bits = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
889 bit = find_next_bit(bm->cur.node->data, bits,
890 bm->cur.node_bit);
891 if (bit < bits) {
892 pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
893 bm->cur.node_bit = bit + 1;
894 return pfn;
895 }
896 } while (rtree_next_node(bm));
897
898 return BM_END_OF_MAP;
899}
900
901/*
902 * This structure represents a range of page frames the contents of which
903 * should not be saved during hibernation.
904 */
905struct nosave_region {
906 struct list_head list;
907 unsigned long start_pfn;
908 unsigned long end_pfn;
909};
910
911static LIST_HEAD(nosave_regions);
912
913static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone)
914{
915 struct rtree_node *node;
916
917 list_for_each_entry(node, &zone->nodes, list)
918 recycle_safe_page(node->data);
919
920 list_for_each_entry(node, &zone->leaves, list)
921 recycle_safe_page(node->data);
922}
923
924static void memory_bm_recycle(struct memory_bitmap *bm)
925{
926 struct mem_zone_bm_rtree *zone;
927 struct linked_page *p_list;
928
929 list_for_each_entry(zone, &bm->zones, list)
930 recycle_zone_bm_rtree(zone);
931
932 p_list = bm->p_list;
933 while (p_list) {
934 struct linked_page *lp = p_list;
935
936 p_list = lp->next;
937 recycle_safe_page(lp);
938 }
939}
940
941/**
942 * register_nosave_region - Register a region of unsaveable memory.
943 *
944 * Register a range of page frames the contents of which should not be saved
945 * during hibernation (to be used in the early initialization code).
946 */
947void __init __register_nosave_region(unsigned long start_pfn,
948 unsigned long end_pfn, int use_kmalloc)
949{
950 struct nosave_region *region;
951
952 if (start_pfn >= end_pfn)
953 return;
954
955 if (!list_empty(&nosave_regions)) {
956 /* Try to extend the previous region (they should be sorted) */
957 region = list_entry(nosave_regions.prev,
958 struct nosave_region, list);
959 if (region->end_pfn == start_pfn) {
960 region->end_pfn = end_pfn;
961 goto Report;
962 }
963 }
964 if (use_kmalloc) {
965 /* During init, this shouldn't fail */
966 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
967 BUG_ON(!region);
968 } else {
969 /* This allocation cannot fail */
970 region = memblock_alloc(sizeof(struct nosave_region),
971 SMP_CACHE_BYTES);
972 if (!region)
973 panic("%s: Failed to allocate %zu bytes\n", __func__,
974 sizeof(struct nosave_region));
975 }
976 region->start_pfn = start_pfn;
977 region->end_pfn = end_pfn;
978 list_add_tail(®ion->list, &nosave_regions);
979 Report:
980 pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n",
981 (unsigned long long) start_pfn << PAGE_SHIFT,
982 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
983}
984
985/*
986 * Set bits in this map correspond to the page frames the contents of which
987 * should not be saved during the suspend.
988 */
989static struct memory_bitmap *forbidden_pages_map;
990
991/* Set bits in this map correspond to free page frames. */
992static struct memory_bitmap *free_pages_map;
993
994/*
995 * Each page frame allocated for creating the image is marked by setting the
996 * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
997 */
998
999void swsusp_set_page_free(struct page *page)
1000{
1001 if (free_pages_map)
1002 memory_bm_set_bit(free_pages_map, page_to_pfn(page));
1003}
1004
1005static int swsusp_page_is_free(struct page *page)
1006{
1007 return free_pages_map ?
1008 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
1009}
1010
1011void swsusp_unset_page_free(struct page *page)
1012{
1013 if (free_pages_map)
1014 memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
1015}
1016
1017static void swsusp_set_page_forbidden(struct page *page)
1018{
1019 if (forbidden_pages_map)
1020 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
1021}
1022
1023int swsusp_page_is_forbidden(struct page *page)
1024{
1025 return forbidden_pages_map ?
1026 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
1027}
1028
1029static void swsusp_unset_page_forbidden(struct page *page)
1030{
1031 if (forbidden_pages_map)
1032 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
1033}
1034
1035/**
1036 * mark_nosave_pages - Mark pages that should not be saved.
1037 * @bm: Memory bitmap.
1038 *
1039 * Set the bits in @bm that correspond to the page frames the contents of which
1040 * should not be saved.
1041 */
1042static void mark_nosave_pages(struct memory_bitmap *bm)
1043{
1044 struct nosave_region *region;
1045
1046 if (list_empty(&nosave_regions))
1047 return;
1048
1049 list_for_each_entry(region, &nosave_regions, list) {
1050 unsigned long pfn;
1051
1052 pr_debug("Marking nosave pages: [mem %#010llx-%#010llx]\n",
1053 (unsigned long long) region->start_pfn << PAGE_SHIFT,
1054 ((unsigned long long) region->end_pfn << PAGE_SHIFT)
1055 - 1);
1056
1057 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
1058 if (pfn_valid(pfn)) {
1059 /*
1060 * It is safe to ignore the result of
1061 * mem_bm_set_bit_check() here, since we won't
1062 * touch the PFNs for which the error is
1063 * returned anyway.
1064 */
1065 mem_bm_set_bit_check(bm, pfn);
1066 }
1067 }
1068}
1069
1070/**
1071 * create_basic_memory_bitmaps - Create bitmaps to hold basic page information.
1072 *
1073 * Create bitmaps needed for marking page frames that should not be saved and
1074 * free page frames. The forbidden_pages_map and free_pages_map pointers are
1075 * only modified if everything goes well, because we don't want the bits to be
1076 * touched before both bitmaps are set up.
1077 */
1078int create_basic_memory_bitmaps(void)
1079{
1080 struct memory_bitmap *bm1, *bm2;
1081 int error = 0;
1082
1083 if (forbidden_pages_map && free_pages_map)
1084 return 0;
1085 else
1086 BUG_ON(forbidden_pages_map || free_pages_map);
1087
1088 bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
1089 if (!bm1)
1090 return -ENOMEM;
1091
1092 error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
1093 if (error)
1094 goto Free_first_object;
1095
1096 bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
1097 if (!bm2)
1098 goto Free_first_bitmap;
1099
1100 error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
1101 if (error)
1102 goto Free_second_object;
1103
1104 forbidden_pages_map = bm1;
1105 free_pages_map = bm2;
1106 mark_nosave_pages(forbidden_pages_map);
1107
1108 pr_debug("Basic memory bitmaps created\n");
1109
1110 return 0;
1111
1112 Free_second_object:
1113 kfree(bm2);
1114 Free_first_bitmap:
1115 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
1116 Free_first_object:
1117 kfree(bm1);
1118 return -ENOMEM;
1119}
1120
1121/**
1122 * free_basic_memory_bitmaps - Free memory bitmaps holding basic information.
1123 *
1124 * Free memory bitmaps allocated by create_basic_memory_bitmaps(). The
1125 * auxiliary pointers are necessary so that the bitmaps themselves are not
1126 * referred to while they are being freed.
1127 */
1128void free_basic_memory_bitmaps(void)
1129{
1130 struct memory_bitmap *bm1, *bm2;
1131
1132 if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
1133 return;
1134
1135 bm1 = forbidden_pages_map;
1136 bm2 = free_pages_map;
1137 forbidden_pages_map = NULL;
1138 free_pages_map = NULL;
1139 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
1140 kfree(bm1);
1141 memory_bm_free(bm2, PG_UNSAFE_CLEAR);
1142 kfree(bm2);
1143
1144 pr_debug("Basic memory bitmaps freed\n");
1145}
1146
1147void clear_free_pages(void)
1148{
1149 struct memory_bitmap *bm = free_pages_map;
1150 unsigned long pfn;
1151
1152 if (WARN_ON(!(free_pages_map)))
1153 return;
1154
1155 if (IS_ENABLED(CONFIG_PAGE_POISONING_ZERO) || want_init_on_free()) {
1156 memory_bm_position_reset(bm);
1157 pfn = memory_bm_next_pfn(bm);
1158 while (pfn != BM_END_OF_MAP) {
1159 if (pfn_valid(pfn))
1160 clear_highpage(pfn_to_page(pfn));
1161
1162 pfn = memory_bm_next_pfn(bm);
1163 }
1164 memory_bm_position_reset(bm);
1165 pr_info("free pages cleared after restore\n");
1166 }
1167}
1168
1169/**
1170 * snapshot_additional_pages - Estimate the number of extra pages needed.
1171 * @zone: Memory zone to carry out the computation for.
1172 *
1173 * Estimate the number of additional pages needed for setting up a hibernation
1174 * image data structures for @zone (usually, the returned value is greater than
1175 * the exact number).
1176 */
1177unsigned int snapshot_additional_pages(struct zone *zone)
1178{
1179 unsigned int rtree, nodes;
1180
1181 rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
1182 rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
1183 LINKED_PAGE_DATA_SIZE);
1184 while (nodes > 1) {
1185 nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
1186 rtree += nodes;
1187 }
1188
1189 return 2 * rtree;
1190}
1191
1192#ifdef CONFIG_HIGHMEM
1193/**
1194 * count_free_highmem_pages - Compute the total number of free highmem pages.
1195 *
1196 * The returned number is system-wide.
1197 */
1198static unsigned int count_free_highmem_pages(void)
1199{
1200 struct zone *zone;
1201 unsigned int cnt = 0;
1202
1203 for_each_populated_zone(zone)
1204 if (is_highmem(zone))
1205 cnt += zone_page_state(zone, NR_FREE_PAGES);
1206
1207 return cnt;
1208}
1209
1210/**
1211 * saveable_highmem_page - Check if a highmem page is saveable.
1212 *
1213 * Determine whether a highmem page should be included in a hibernation image.
1214 *
1215 * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
1216 * and it isn't part of a free chunk of pages.
1217 */
1218static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
1219{
1220 struct page *page;
1221
1222 if (!pfn_valid(pfn))
1223 return NULL;
1224
1225 page = pfn_to_online_page(pfn);
1226 if (!page || page_zone(page) != zone)
1227 return NULL;
1228
1229 BUG_ON(!PageHighMem(page));
1230
1231 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
1232 return NULL;
1233
1234 if (PageReserved(page) || PageOffline(page))
1235 return NULL;
1236
1237 if (page_is_guard(page))
1238 return NULL;
1239
1240 return page;
1241}
1242
1243/**
1244 * count_highmem_pages - Compute the total number of saveable highmem pages.
1245 */
1246static unsigned int count_highmem_pages(void)
1247{
1248 struct zone *zone;
1249 unsigned int n = 0;
1250
1251 for_each_populated_zone(zone) {
1252 unsigned long pfn, max_zone_pfn;
1253
1254 if (!is_highmem(zone))
1255 continue;
1256
1257 mark_free_pages(zone);
1258 max_zone_pfn = zone_end_pfn(zone);
1259 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1260 if (saveable_highmem_page(zone, pfn))
1261 n++;
1262 }
1263 return n;
1264}
1265#else
1266static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
1267{
1268 return NULL;
1269}
1270#endif /* CONFIG_HIGHMEM */
1271
1272/**
1273 * saveable_page - Check if the given page is saveable.
1274 *
1275 * Determine whether a non-highmem page should be included in a hibernation
1276 * image.
1277 *
1278 * We should save the page if it isn't Nosave, and is not in the range
1279 * of pages statically defined as 'unsaveable', and it isn't part of
1280 * a free chunk of pages.
1281 */
1282static struct page *saveable_page(struct zone *zone, unsigned long pfn)
1283{
1284 struct page *page;
1285
1286 if (!pfn_valid(pfn))
1287 return NULL;
1288
1289 page = pfn_to_online_page(pfn);
1290 if (!page || page_zone(page) != zone)
1291 return NULL;
1292
1293 BUG_ON(PageHighMem(page));
1294
1295 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
1296 return NULL;
1297
1298 if (PageOffline(page))
1299 return NULL;
1300
1301 if (PageReserved(page)
1302 && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
1303 return NULL;
1304
1305 if (page_is_guard(page))
1306 return NULL;
1307
1308 return page;
1309}
1310
1311/**
1312 * count_data_pages - Compute the total number of saveable non-highmem pages.
1313 */
1314static unsigned int count_data_pages(void)
1315{
1316 struct zone *zone;
1317 unsigned long pfn, max_zone_pfn;
1318 unsigned int n = 0;
1319
1320 for_each_populated_zone(zone) {
1321 if (is_highmem(zone))
1322 continue;
1323
1324 mark_free_pages(zone);
1325 max_zone_pfn = zone_end_pfn(zone);
1326 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1327 if (saveable_page(zone, pfn))
1328 n++;
1329 }
1330 return n;
1331}
1332
1333/*
1334 * This is needed, because copy_page and memcpy are not usable for copying
1335 * task structs.
1336 */
1337static inline void do_copy_page(long *dst, long *src)
1338{
1339 int n;
1340
1341 for (n = PAGE_SIZE / sizeof(long); n; n--)
1342 *dst++ = *src++;
1343}
1344
1345/**
1346 * safe_copy_page - Copy a page in a safe way.
1347 *
1348 * Check if the page we are going to copy is marked as present in the kernel
1349 * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
1350 * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
1351 * always returns 'true'.
1352 */
1353static void safe_copy_page(void *dst, struct page *s_page)
1354{
1355 if (kernel_page_present(s_page)) {
1356 do_copy_page(dst, page_address(s_page));
1357 } else {
1358 kernel_map_pages(s_page, 1, 1);
1359 do_copy_page(dst, page_address(s_page));
1360 kernel_map_pages(s_page, 1, 0);
1361 }
1362}
1363
1364#ifdef CONFIG_HIGHMEM
1365static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
1366{
1367 return is_highmem(zone) ?
1368 saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
1369}
1370
1371static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1372{
1373 struct page *s_page, *d_page;
1374 void *src, *dst;
1375
1376 s_page = pfn_to_page(src_pfn);
1377 d_page = pfn_to_page(dst_pfn);
1378 if (PageHighMem(s_page)) {
1379 src = kmap_atomic(s_page);
1380 dst = kmap_atomic(d_page);
1381 do_copy_page(dst, src);
1382 kunmap_atomic(dst);
1383 kunmap_atomic(src);
1384 } else {
1385 if (PageHighMem(d_page)) {
1386 /*
1387 * The page pointed to by src may contain some kernel
1388 * data modified by kmap_atomic()
1389 */
1390 safe_copy_page(buffer, s_page);
1391 dst = kmap_atomic(d_page);
1392 copy_page(dst, buffer);
1393 kunmap_atomic(dst);
1394 } else {
1395 safe_copy_page(page_address(d_page), s_page);
1396 }
1397 }
1398}
1399#else
1400#define page_is_saveable(zone, pfn) saveable_page(zone, pfn)
1401
1402static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1403{
1404 safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1405 pfn_to_page(src_pfn));
1406}
1407#endif /* CONFIG_HIGHMEM */
1408
1409static void copy_data_pages(struct memory_bitmap *copy_bm,
1410 struct memory_bitmap *orig_bm)
1411{
1412 struct zone *zone;
1413 unsigned long pfn;
1414
1415 for_each_populated_zone(zone) {
1416 unsigned long max_zone_pfn;
1417
1418 mark_free_pages(zone);
1419 max_zone_pfn = zone_end_pfn(zone);
1420 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1421 if (page_is_saveable(zone, pfn))
1422 memory_bm_set_bit(orig_bm, pfn);
1423 }
1424 memory_bm_position_reset(orig_bm);
1425 memory_bm_position_reset(copy_bm);
1426 for(;;) {
1427 pfn = memory_bm_next_pfn(orig_bm);
1428 if (unlikely(pfn == BM_END_OF_MAP))
1429 break;
1430 copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
1431 }
1432}
1433
1434/* Total number of image pages */
1435static unsigned int nr_copy_pages;
1436/* Number of pages needed for saving the original pfns of the image pages */
1437static unsigned int nr_meta_pages;
1438/*
1439 * Numbers of normal and highmem page frames allocated for hibernation image
1440 * before suspending devices.
1441 */
1442static unsigned int alloc_normal, alloc_highmem;
1443/*
1444 * Memory bitmap used for marking saveable pages (during hibernation) or
1445 * hibernation image pages (during restore)
1446 */
1447static struct memory_bitmap orig_bm;
1448/*
1449 * Memory bitmap used during hibernation for marking allocated page frames that
1450 * will contain copies of saveable pages. During restore it is initially used
1451 * for marking hibernation image pages, but then the set bits from it are
1452 * duplicated in @orig_bm and it is released. On highmem systems it is next
1453 * used for marking "safe" highmem pages, but it has to be reinitialized for
1454 * this purpose.
1455 */
1456static struct memory_bitmap copy_bm;
1457
1458/**
1459 * swsusp_free - Free pages allocated for hibernation image.
1460 *
1461 * Image pages are alocated before snapshot creation, so they need to be
1462 * released after resume.
1463 */
1464void swsusp_free(void)
1465{
1466 unsigned long fb_pfn, fr_pfn;
1467
1468 if (!forbidden_pages_map || !free_pages_map)
1469 goto out;
1470
1471 memory_bm_position_reset(forbidden_pages_map);
1472 memory_bm_position_reset(free_pages_map);
1473
1474loop:
1475 fr_pfn = memory_bm_next_pfn(free_pages_map);
1476 fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
1477
1478 /*
1479 * Find the next bit set in both bitmaps. This is guaranteed to
1480 * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
1481 */
1482 do {
1483 if (fb_pfn < fr_pfn)
1484 fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
1485 if (fr_pfn < fb_pfn)
1486 fr_pfn = memory_bm_next_pfn(free_pages_map);
1487 } while (fb_pfn != fr_pfn);
1488
1489 if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
1490 struct page *page = pfn_to_page(fr_pfn);
1491
1492 memory_bm_clear_current(forbidden_pages_map);
1493 memory_bm_clear_current(free_pages_map);
1494 hibernate_restore_unprotect_page(page_address(page));
1495 __free_page(page);
1496 goto loop;
1497 }
1498
1499out:
1500 nr_copy_pages = 0;
1501 nr_meta_pages = 0;
1502 restore_pblist = NULL;
1503 buffer = NULL;
1504 alloc_normal = 0;
1505 alloc_highmem = 0;
1506 hibernate_restore_protection_end();
1507}
1508
1509/* Helper functions used for the shrinking of memory. */
1510
1511#define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN)
1512
1513/**
1514 * preallocate_image_pages - Allocate a number of pages for hibernation image.
1515 * @nr_pages: Number of page frames to allocate.
1516 * @mask: GFP flags to use for the allocation.
1517 *
1518 * Return value: Number of page frames actually allocated
1519 */
1520static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1521{
1522 unsigned long nr_alloc = 0;
1523
1524 while (nr_pages > 0) {
1525 struct page *page;
1526
1527 page = alloc_image_page(mask);
1528 if (!page)
1529 break;
1530 memory_bm_set_bit(©_bm, page_to_pfn(page));
1531 if (PageHighMem(page))
1532 alloc_highmem++;
1533 else
1534 alloc_normal++;
1535 nr_pages--;
1536 nr_alloc++;
1537 }
1538
1539 return nr_alloc;
1540}
1541
1542static unsigned long preallocate_image_memory(unsigned long nr_pages,
1543 unsigned long avail_normal)
1544{
1545 unsigned long alloc;
1546
1547 if (avail_normal <= alloc_normal)
1548 return 0;
1549
1550 alloc = avail_normal - alloc_normal;
1551 if (nr_pages < alloc)
1552 alloc = nr_pages;
1553
1554 return preallocate_image_pages(alloc, GFP_IMAGE);
1555}
1556
1557#ifdef CONFIG_HIGHMEM
1558static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1559{
1560 return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1561}
1562
1563/**
1564 * __fraction - Compute (an approximation of) x * (multiplier / base).
1565 */
1566static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1567{
1568 return div64_u64(x * multiplier, base);
1569}
1570
1571static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1572 unsigned long highmem,
1573 unsigned long total)
1574{
1575 unsigned long alloc = __fraction(nr_pages, highmem, total);
1576
1577 return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1578}
1579#else /* CONFIG_HIGHMEM */
1580static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1581{
1582 return 0;
1583}
1584
1585static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1586 unsigned long highmem,
1587 unsigned long total)
1588{
1589 return 0;
1590}
1591#endif /* CONFIG_HIGHMEM */
1592
1593/**
1594 * free_unnecessary_pages - Release preallocated pages not needed for the image.
1595 */
1596static unsigned long free_unnecessary_pages(void)
1597{
1598 unsigned long save, to_free_normal, to_free_highmem, free;
1599
1600 save = count_data_pages();
1601 if (alloc_normal >= save) {
1602 to_free_normal = alloc_normal - save;
1603 save = 0;
1604 } else {
1605 to_free_normal = 0;
1606 save -= alloc_normal;
1607 }
1608 save += count_highmem_pages();
1609 if (alloc_highmem >= save) {
1610 to_free_highmem = alloc_highmem - save;
1611 } else {
1612 to_free_highmem = 0;
1613 save -= alloc_highmem;
1614 if (to_free_normal > save)
1615 to_free_normal -= save;
1616 else
1617 to_free_normal = 0;
1618 }
1619 free = to_free_normal + to_free_highmem;
1620
1621 memory_bm_position_reset(©_bm);
1622
1623 while (to_free_normal > 0 || to_free_highmem > 0) {
1624 unsigned long pfn = memory_bm_next_pfn(©_bm);
1625 struct page *page = pfn_to_page(pfn);
1626
1627 if (PageHighMem(page)) {
1628 if (!to_free_highmem)
1629 continue;
1630 to_free_highmem--;
1631 alloc_highmem--;
1632 } else {
1633 if (!to_free_normal)
1634 continue;
1635 to_free_normal--;
1636 alloc_normal--;
1637 }
1638 memory_bm_clear_bit(©_bm, pfn);
1639 swsusp_unset_page_forbidden(page);
1640 swsusp_unset_page_free(page);
1641 __free_page(page);
1642 }
1643
1644 return free;
1645}
1646
1647/**
1648 * minimum_image_size - Estimate the minimum acceptable size of an image.
1649 * @saveable: Number of saveable pages in the system.
1650 *
1651 * We want to avoid attempting to free too much memory too hard, so estimate the
1652 * minimum acceptable size of a hibernation image to use as the lower limit for
1653 * preallocating memory.
1654 *
1655 * We assume that the minimum image size should be proportional to
1656 *
1657 * [number of saveable pages] - [number of pages that can be freed in theory]
1658 *
1659 * where the second term is the sum of (1) reclaimable slab pages, (2) active
1660 * and (3) inactive anonymous pages, (4) active and (5) inactive file pages.
1661 */
1662static unsigned long minimum_image_size(unsigned long saveable)
1663{
1664 unsigned long size;
1665
1666 size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B)
1667 + global_node_page_state(NR_ACTIVE_ANON)
1668 + global_node_page_state(NR_INACTIVE_ANON)
1669 + global_node_page_state(NR_ACTIVE_FILE)
1670 + global_node_page_state(NR_INACTIVE_FILE);
1671
1672 return saveable <= size ? 0 : saveable - size;
1673}
1674
1675/**
1676 * hibernate_preallocate_memory - Preallocate memory for hibernation image.
1677 *
1678 * To create a hibernation image it is necessary to make a copy of every page
1679 * frame in use. We also need a number of page frames to be free during
1680 * hibernation for allocations made while saving the image and for device
1681 * drivers, in case they need to allocate memory from their hibernation
1682 * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
1683 * estimate) and reserved_size divided by PAGE_SIZE (which is tunable through
1684 * /sys/power/reserved_size, respectively). To make this happen, we compute the
1685 * total number of available page frames and allocate at least
1686 *
1687 * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2
1688 * + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
1689 *
1690 * of them, which corresponds to the maximum size of a hibernation image.
1691 *
1692 * If image_size is set below the number following from the above formula,
1693 * the preallocation of memory is continued until the total number of saveable
1694 * pages in the system is below the requested image size or the minimum
1695 * acceptable image size returned by minimum_image_size(), whichever is greater.
1696 */
1697int hibernate_preallocate_memory(void)
1698{
1699 struct zone *zone;
1700 unsigned long saveable, size, max_size, count, highmem, pages = 0;
1701 unsigned long alloc, save_highmem, pages_highmem, avail_normal;
1702 ktime_t start, stop;
1703 int error;
1704
1705 pr_info("Preallocating image memory\n");
1706 start = ktime_get();
1707
1708 error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
1709 if (error) {
1710 pr_err("Cannot allocate original bitmap\n");
1711 goto err_out;
1712 }
1713
1714 error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY);
1715 if (error) {
1716 pr_err("Cannot allocate copy bitmap\n");
1717 goto err_out;
1718 }
1719
1720 alloc_normal = 0;
1721 alloc_highmem = 0;
1722
1723 /* Count the number of saveable data pages. */
1724 save_highmem = count_highmem_pages();
1725 saveable = count_data_pages();
1726
1727 /*
1728 * Compute the total number of page frames we can use (count) and the
1729 * number of pages needed for image metadata (size).
1730 */
1731 count = saveable;
1732 saveable += save_highmem;
1733 highmem = save_highmem;
1734 size = 0;
1735 for_each_populated_zone(zone) {
1736 size += snapshot_additional_pages(zone);
1737 if (is_highmem(zone))
1738 highmem += zone_page_state(zone, NR_FREE_PAGES);
1739 else
1740 count += zone_page_state(zone, NR_FREE_PAGES);
1741 }
1742 avail_normal = count;
1743 count += highmem;
1744 count -= totalreserve_pages;
1745
1746 /* Compute the maximum number of saveable pages to leave in memory. */
1747 max_size = (count - (size + PAGES_FOR_IO)) / 2
1748 - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
1749 /* Compute the desired number of image pages specified by image_size. */
1750 size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1751 if (size > max_size)
1752 size = max_size;
1753 /*
1754 * If the desired number of image pages is at least as large as the
1755 * current number of saveable pages in memory, allocate page frames for
1756 * the image and we're done.
1757 */
1758 if (size >= saveable) {
1759 pages = preallocate_image_highmem(save_highmem);
1760 pages += preallocate_image_memory(saveable - pages, avail_normal);
1761 goto out;
1762 }
1763
1764 /* Estimate the minimum size of the image. */
1765 pages = minimum_image_size(saveable);
1766 /*
1767 * To avoid excessive pressure on the normal zone, leave room in it to
1768 * accommodate an image of the minimum size (unless it's already too
1769 * small, in which case don't preallocate pages from it at all).
1770 */
1771 if (avail_normal > pages)
1772 avail_normal -= pages;
1773 else
1774 avail_normal = 0;
1775 if (size < pages)
1776 size = min_t(unsigned long, pages, max_size);
1777
1778 /*
1779 * Let the memory management subsystem know that we're going to need a
1780 * large number of page frames to allocate and make it free some memory.
1781 * NOTE: If this is not done, performance will be hurt badly in some
1782 * test cases.
1783 */
1784 shrink_all_memory(saveable - size);
1785
1786 /*
1787 * The number of saveable pages in memory was too high, so apply some
1788 * pressure to decrease it. First, make room for the largest possible
1789 * image and fail if that doesn't work. Next, try to decrease the size
1790 * of the image as much as indicated by 'size' using allocations from
1791 * highmem and non-highmem zones separately.
1792 */
1793 pages_highmem = preallocate_image_highmem(highmem / 2);
1794 alloc = count - max_size;
1795 if (alloc > pages_highmem)
1796 alloc -= pages_highmem;
1797 else
1798 alloc = 0;
1799 pages = preallocate_image_memory(alloc, avail_normal);
1800 if (pages < alloc) {
1801 /* We have exhausted non-highmem pages, try highmem. */
1802 alloc -= pages;
1803 pages += pages_highmem;
1804 pages_highmem = preallocate_image_highmem(alloc);
1805 if (pages_highmem < alloc) {
1806 pr_err("Image allocation is %lu pages short\n",
1807 alloc - pages_highmem);
1808 goto err_out;
1809 }
1810 pages += pages_highmem;
1811 /*
1812 * size is the desired number of saveable pages to leave in
1813 * memory, so try to preallocate (all memory - size) pages.
1814 */
1815 alloc = (count - pages) - size;
1816 pages += preallocate_image_highmem(alloc);
1817 } else {
1818 /*
1819 * There are approximately max_size saveable pages at this point
1820 * and we want to reduce this number down to size.
1821 */
1822 alloc = max_size - size;
1823 size = preallocate_highmem_fraction(alloc, highmem, count);
1824 pages_highmem += size;
1825 alloc -= size;
1826 size = preallocate_image_memory(alloc, avail_normal);
1827 pages_highmem += preallocate_image_highmem(alloc - size);
1828 pages += pages_highmem + size;
1829 }
1830
1831 /*
1832 * We only need as many page frames for the image as there are saveable
1833 * pages in memory, but we have allocated more. Release the excessive
1834 * ones now.
1835 */
1836 pages -= free_unnecessary_pages();
1837
1838 out:
1839 stop = ktime_get();
1840 pr_info("Allocated %lu pages for snapshot\n", pages);
1841 swsusp_show_speed(start, stop, pages, "Allocated");
1842
1843 return 0;
1844
1845 err_out:
1846 swsusp_free();
1847 return -ENOMEM;
1848}
1849
1850#ifdef CONFIG_HIGHMEM
1851/**
1852 * count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
1853 *
1854 * Compute the number of non-highmem pages that will be necessary for creating
1855 * copies of highmem pages.
1856 */
1857static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
1858{
1859 unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
1860
1861 if (free_highmem >= nr_highmem)
1862 nr_highmem = 0;
1863 else
1864 nr_highmem -= free_highmem;
1865
1866 return nr_highmem;
1867}
1868#else
1869static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
1870#endif /* CONFIG_HIGHMEM */
1871
1872/**
1873 * enough_free_mem - Check if there is enough free memory for the image.
1874 */
1875static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
1876{
1877 struct zone *zone;
1878 unsigned int free = alloc_normal;
1879
1880 for_each_populated_zone(zone)
1881 if (!is_highmem(zone))
1882 free += zone_page_state(zone, NR_FREE_PAGES);
1883
1884 nr_pages += count_pages_for_highmem(nr_highmem);
1885 pr_debug("Normal pages needed: %u + %u, available pages: %u\n",
1886 nr_pages, PAGES_FOR_IO, free);
1887
1888 return free > nr_pages + PAGES_FOR_IO;
1889}
1890
1891#ifdef CONFIG_HIGHMEM
1892/**
1893 * get_highmem_buffer - Allocate a buffer for highmem pages.
1894 *
1895 * If there are some highmem pages in the hibernation image, we may need a
1896 * buffer to copy them and/or load their data.
1897 */
1898static inline int get_highmem_buffer(int safe_needed)
1899{
1900 buffer = get_image_page(GFP_ATOMIC, safe_needed);
1901 return buffer ? 0 : -ENOMEM;
1902}
1903
1904/**
1905 * alloc_highmem_image_pages - Allocate some highmem pages for the image.
1906 *
1907 * Try to allocate as many pages as needed, but if the number of free highmem
1908 * pages is less than that, allocate them all.
1909 */
1910static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
1911 unsigned int nr_highmem)
1912{
1913 unsigned int to_alloc = count_free_highmem_pages();
1914
1915 if (to_alloc > nr_highmem)
1916 to_alloc = nr_highmem;
1917
1918 nr_highmem -= to_alloc;
1919 while (to_alloc-- > 0) {
1920 struct page *page;
1921
1922 page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM);
1923 memory_bm_set_bit(bm, page_to_pfn(page));
1924 }
1925 return nr_highmem;
1926}
1927#else
1928static inline int get_highmem_buffer(int safe_needed) { return 0; }
1929
1930static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
1931 unsigned int n) { return 0; }
1932#endif /* CONFIG_HIGHMEM */
1933
1934/**
1935 * swsusp_alloc - Allocate memory for hibernation image.
1936 *
1937 * We first try to allocate as many highmem pages as there are
1938 * saveable highmem pages in the system. If that fails, we allocate
1939 * non-highmem pages for the copies of the remaining highmem ones.
1940 *
1941 * In this approach it is likely that the copies of highmem pages will
1942 * also be located in the high memory, because of the way in which
1943 * copy_data_pages() works.
1944 */
1945static int swsusp_alloc(struct memory_bitmap *copy_bm,
1946 unsigned int nr_pages, unsigned int nr_highmem)
1947{
1948 if (nr_highmem > 0) {
1949 if (get_highmem_buffer(PG_ANY))
1950 goto err_out;
1951 if (nr_highmem > alloc_highmem) {
1952 nr_highmem -= alloc_highmem;
1953 nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
1954 }
1955 }
1956 if (nr_pages > alloc_normal) {
1957 nr_pages -= alloc_normal;
1958 while (nr_pages-- > 0) {
1959 struct page *page;
1960
1961 page = alloc_image_page(GFP_ATOMIC);
1962 if (!page)
1963 goto err_out;
1964 memory_bm_set_bit(copy_bm, page_to_pfn(page));
1965 }
1966 }
1967
1968 return 0;
1969
1970 err_out:
1971 swsusp_free();
1972 return -ENOMEM;
1973}
1974
1975asmlinkage __visible int swsusp_save(void)
1976{
1977 unsigned int nr_pages, nr_highmem;
1978
1979 pr_info("Creating image:\n");
1980
1981 drain_local_pages(NULL);
1982 nr_pages = count_data_pages();
1983 nr_highmem = count_highmem_pages();
1984 pr_info("Need to copy %u pages\n", nr_pages + nr_highmem);
1985
1986 if (!enough_free_mem(nr_pages, nr_highmem)) {
1987 pr_err("Not enough free memory\n");
1988 return -ENOMEM;
1989 }
1990
1991 if (swsusp_alloc(©_bm, nr_pages, nr_highmem)) {
1992 pr_err("Memory allocation failed\n");
1993 return -ENOMEM;
1994 }
1995
1996 /*
1997 * During allocating of suspend pagedir, new cold pages may appear.
1998 * Kill them.
1999 */
2000 drain_local_pages(NULL);
2001 copy_data_pages(©_bm, &orig_bm);
2002
2003 /*
2004 * End of critical section. From now on, we can write to memory,
2005 * but we should not touch disk. This specially means we must _not_
2006 * touch swap space! Except we must write out our image of course.
2007 */
2008
2009 nr_pages += nr_highmem;
2010 nr_copy_pages = nr_pages;
2011 nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
2012
2013 pr_info("Image created (%d pages copied)\n", nr_pages);
2014
2015 return 0;
2016}
2017
2018#ifndef CONFIG_ARCH_HIBERNATION_HEADER
2019static int init_header_complete(struct swsusp_info *info)
2020{
2021 memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
2022 info->version_code = LINUX_VERSION_CODE;
2023 return 0;
2024}
2025
2026static const char *check_image_kernel(struct swsusp_info *info)
2027{
2028 if (info->version_code != LINUX_VERSION_CODE)
2029 return "kernel version";
2030 if (strcmp(info->uts.sysname,init_utsname()->sysname))
2031 return "system type";
2032 if (strcmp(info->uts.release,init_utsname()->release))
2033 return "kernel release";
2034 if (strcmp(info->uts.version,init_utsname()->version))
2035 return "version";
2036 if (strcmp(info->uts.machine,init_utsname()->machine))
2037 return "machine";
2038 return NULL;
2039}
2040#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
2041
2042unsigned long snapshot_get_image_size(void)
2043{
2044 return nr_copy_pages + nr_meta_pages + 1;
2045}
2046
2047static int init_header(struct swsusp_info *info)
2048{
2049 memset(info, 0, sizeof(struct swsusp_info));
2050 info->num_physpages = get_num_physpages();
2051 info->image_pages = nr_copy_pages;
2052 info->pages = snapshot_get_image_size();
2053 info->size = info->pages;
2054 info->size <<= PAGE_SHIFT;
2055 return init_header_complete(info);
2056}
2057
2058/**
2059 * pack_pfns - Prepare PFNs for saving.
2060 * @bm: Memory bitmap.
2061 * @buf: Memory buffer to store the PFNs in.
2062 *
2063 * PFNs corresponding to set bits in @bm are stored in the area of memory
2064 * pointed to by @buf (1 page at a time).
2065 */
2066static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
2067{
2068 int j;
2069
2070 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2071 buf[j] = memory_bm_next_pfn(bm);
2072 if (unlikely(buf[j] == BM_END_OF_MAP))
2073 break;
2074 }
2075}
2076
2077/**
2078 * snapshot_read_next - Get the address to read the next image page from.
2079 * @handle: Snapshot handle to be used for the reading.
2080 *
2081 * On the first call, @handle should point to a zeroed snapshot_handle
2082 * structure. The structure gets populated then and a pointer to it should be
2083 * passed to this function every next time.
2084 *
2085 * On success, the function returns a positive number. Then, the caller
2086 * is allowed to read up to the returned number of bytes from the memory
2087 * location computed by the data_of() macro.
2088 *
2089 * The function returns 0 to indicate the end of the data stream condition,
2090 * and negative numbers are returned on errors. If that happens, the structure
2091 * pointed to by @handle is not updated and should not be used any more.
2092 */
2093int snapshot_read_next(struct snapshot_handle *handle)
2094{
2095 if (handle->cur > nr_meta_pages + nr_copy_pages)
2096 return 0;
2097
2098 if (!buffer) {
2099 /* This makes the buffer be freed by swsusp_free() */
2100 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2101 if (!buffer)
2102 return -ENOMEM;
2103 }
2104 if (!handle->cur) {
2105 int error;
2106
2107 error = init_header((struct swsusp_info *)buffer);
2108 if (error)
2109 return error;
2110 handle->buffer = buffer;
2111 memory_bm_position_reset(&orig_bm);
2112 memory_bm_position_reset(©_bm);
2113 } else if (handle->cur <= nr_meta_pages) {
2114 clear_page(buffer);
2115 pack_pfns(buffer, &orig_bm);
2116 } else {
2117 struct page *page;
2118
2119 page = pfn_to_page(memory_bm_next_pfn(©_bm));
2120 if (PageHighMem(page)) {
2121 /*
2122 * Highmem pages are copied to the buffer,
2123 * because we can't return with a kmapped
2124 * highmem page (we may not be called again).
2125 */
2126 void *kaddr;
2127
2128 kaddr = kmap_atomic(page);
2129 copy_page(buffer, kaddr);
2130 kunmap_atomic(kaddr);
2131 handle->buffer = buffer;
2132 } else {
2133 handle->buffer = page_address(page);
2134 }
2135 }
2136 handle->cur++;
2137 return PAGE_SIZE;
2138}
2139
2140static void duplicate_memory_bitmap(struct memory_bitmap *dst,
2141 struct memory_bitmap *src)
2142{
2143 unsigned long pfn;
2144
2145 memory_bm_position_reset(src);
2146 pfn = memory_bm_next_pfn(src);
2147 while (pfn != BM_END_OF_MAP) {
2148 memory_bm_set_bit(dst, pfn);
2149 pfn = memory_bm_next_pfn(src);
2150 }
2151}
2152
2153/**
2154 * mark_unsafe_pages - Mark pages that were used before hibernation.
2155 *
2156 * Mark the pages that cannot be used for storing the image during restoration,
2157 * because they conflict with the pages that had been used before hibernation.
2158 */
2159static void mark_unsafe_pages(struct memory_bitmap *bm)
2160{
2161 unsigned long pfn;
2162
2163 /* Clear the "free"/"unsafe" bit for all PFNs */
2164 memory_bm_position_reset(free_pages_map);
2165 pfn = memory_bm_next_pfn(free_pages_map);
2166 while (pfn != BM_END_OF_MAP) {
2167 memory_bm_clear_current(free_pages_map);
2168 pfn = memory_bm_next_pfn(free_pages_map);
2169 }
2170
2171 /* Mark pages that correspond to the "original" PFNs as "unsafe" */
2172 duplicate_memory_bitmap(free_pages_map, bm);
2173
2174 allocated_unsafe_pages = 0;
2175}
2176
2177static int check_header(struct swsusp_info *info)
2178{
2179 const char *reason;
2180
2181 reason = check_image_kernel(info);
2182 if (!reason && info->num_physpages != get_num_physpages())
2183 reason = "memory size";
2184 if (reason) {
2185 pr_err("Image mismatch: %s\n", reason);
2186 return -EPERM;
2187 }
2188 return 0;
2189}
2190
2191/**
2192 * load header - Check the image header and copy the data from it.
2193 */
2194static int load_header(struct swsusp_info *info)
2195{
2196 int error;
2197
2198 restore_pblist = NULL;
2199 error = check_header(info);
2200 if (!error) {
2201 nr_copy_pages = info->image_pages;
2202 nr_meta_pages = info->pages - info->image_pages - 1;
2203 }
2204 return error;
2205}
2206
2207/**
2208 * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
2209 * @bm: Memory bitmap.
2210 * @buf: Area of memory containing the PFNs.
2211 *
2212 * For each element of the array pointed to by @buf (1 page at a time), set the
2213 * corresponding bit in @bm.
2214 */
2215static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
2216{
2217 int j;
2218
2219 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2220 if (unlikely(buf[j] == BM_END_OF_MAP))
2221 break;
2222
2223 if (pfn_valid(buf[j]) && memory_bm_pfn_present(bm, buf[j]))
2224 memory_bm_set_bit(bm, buf[j]);
2225 else
2226 return -EFAULT;
2227 }
2228
2229 return 0;
2230}
2231
2232#ifdef CONFIG_HIGHMEM
2233/*
2234 * struct highmem_pbe is used for creating the list of highmem pages that
2235 * should be restored atomically during the resume from disk, because the page
2236 * frames they have occupied before the suspend are in use.
2237 */
2238struct highmem_pbe {
2239 struct page *copy_page; /* data is here now */
2240 struct page *orig_page; /* data was here before the suspend */
2241 struct highmem_pbe *next;
2242};
2243
2244/*
2245 * List of highmem PBEs needed for restoring the highmem pages that were
2246 * allocated before the suspend and included in the suspend image, but have
2247 * also been allocated by the "resume" kernel, so their contents cannot be
2248 * written directly to their "original" page frames.
2249 */
2250static struct highmem_pbe *highmem_pblist;
2251
2252/**
2253 * count_highmem_image_pages - Compute the number of highmem pages in the image.
2254 * @bm: Memory bitmap.
2255 *
2256 * The bits in @bm that correspond to image pages are assumed to be set.
2257 */
2258static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
2259{
2260 unsigned long pfn;
2261 unsigned int cnt = 0;
2262
2263 memory_bm_position_reset(bm);
2264 pfn = memory_bm_next_pfn(bm);
2265 while (pfn != BM_END_OF_MAP) {
2266 if (PageHighMem(pfn_to_page(pfn)))
2267 cnt++;
2268
2269 pfn = memory_bm_next_pfn(bm);
2270 }
2271 return cnt;
2272}
2273
2274static unsigned int safe_highmem_pages;
2275
2276static struct memory_bitmap *safe_highmem_bm;
2277
2278/**
2279 * prepare_highmem_image - Allocate memory for loading highmem data from image.
2280 * @bm: Pointer to an uninitialized memory bitmap structure.
2281 * @nr_highmem_p: Pointer to the number of highmem image pages.
2282 *
2283 * Try to allocate as many highmem pages as there are highmem image pages
2284 * (@nr_highmem_p points to the variable containing the number of highmem image
2285 * pages). The pages that are "safe" (ie. will not be overwritten when the
2286 * hibernation image is restored entirely) have the corresponding bits set in
2287 * @bm (it must be unitialized).
2288 *
2289 * NOTE: This function should not be called if there are no highmem image pages.
2290 */
2291static int prepare_highmem_image(struct memory_bitmap *bm,
2292 unsigned int *nr_highmem_p)
2293{
2294 unsigned int to_alloc;
2295
2296 if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
2297 return -ENOMEM;
2298
2299 if (get_highmem_buffer(PG_SAFE))
2300 return -ENOMEM;
2301
2302 to_alloc = count_free_highmem_pages();
2303 if (to_alloc > *nr_highmem_p)
2304 to_alloc = *nr_highmem_p;
2305 else
2306 *nr_highmem_p = to_alloc;
2307
2308 safe_highmem_pages = 0;
2309 while (to_alloc-- > 0) {
2310 struct page *page;
2311
2312 page = alloc_page(__GFP_HIGHMEM);
2313 if (!swsusp_page_is_free(page)) {
2314 /* The page is "safe", set its bit the bitmap */
2315 memory_bm_set_bit(bm, page_to_pfn(page));
2316 safe_highmem_pages++;
2317 }
2318 /* Mark the page as allocated */
2319 swsusp_set_page_forbidden(page);
2320 swsusp_set_page_free(page);
2321 }
2322 memory_bm_position_reset(bm);
2323 safe_highmem_bm = bm;
2324 return 0;
2325}
2326
2327static struct page *last_highmem_page;
2328
2329/**
2330 * get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
2331 *
2332 * For a given highmem image page get a buffer that suspend_write_next() should
2333 * return to its caller to write to.
2334 *
2335 * If the page is to be saved to its "original" page frame or a copy of
2336 * the page is to be made in the highmem, @buffer is returned. Otherwise,
2337 * the copy of the page is to be made in normal memory, so the address of
2338 * the copy is returned.
2339 *
2340 * If @buffer is returned, the caller of suspend_write_next() will write
2341 * the page's contents to @buffer, so they will have to be copied to the
2342 * right location on the next call to suspend_write_next() and it is done
2343 * with the help of copy_last_highmem_page(). For this purpose, if
2344 * @buffer is returned, @last_highmem_page is set to the page to which
2345 * the data will have to be copied from @buffer.
2346 */
2347static void *get_highmem_page_buffer(struct page *page,
2348 struct chain_allocator *ca)
2349{
2350 struct highmem_pbe *pbe;
2351 void *kaddr;
2352
2353 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
2354 /*
2355 * We have allocated the "original" page frame and we can
2356 * use it directly to store the loaded page.
2357 */
2358 last_highmem_page = page;
2359 return buffer;
2360 }
2361 /*
2362 * The "original" page frame has not been allocated and we have to
2363 * use a "safe" page frame to store the loaded page.
2364 */
2365 pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
2366 if (!pbe) {
2367 swsusp_free();
2368 return ERR_PTR(-ENOMEM);
2369 }
2370 pbe->orig_page = page;
2371 if (safe_highmem_pages > 0) {
2372 struct page *tmp;
2373
2374 /* Copy of the page will be stored in high memory */
2375 kaddr = buffer;
2376 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
2377 safe_highmem_pages--;
2378 last_highmem_page = tmp;
2379 pbe->copy_page = tmp;
2380 } else {
2381 /* Copy of the page will be stored in normal memory */
2382 kaddr = safe_pages_list;
2383 safe_pages_list = safe_pages_list->next;
2384 pbe->copy_page = virt_to_page(kaddr);
2385 }
2386 pbe->next = highmem_pblist;
2387 highmem_pblist = pbe;
2388 return kaddr;
2389}
2390
2391/**
2392 * copy_last_highmem_page - Copy most the most recent highmem image page.
2393 *
2394 * Copy the contents of a highmem image from @buffer, where the caller of
2395 * snapshot_write_next() has stored them, to the right location represented by
2396 * @last_highmem_page .
2397 */
2398static void copy_last_highmem_page(void)
2399{
2400 if (last_highmem_page) {
2401 void *dst;
2402
2403 dst = kmap_atomic(last_highmem_page);
2404 copy_page(dst, buffer);
2405 kunmap_atomic(dst);
2406 last_highmem_page = NULL;
2407 }
2408}
2409
2410static inline int last_highmem_page_copied(void)
2411{
2412 return !last_highmem_page;
2413}
2414
2415static inline void free_highmem_data(void)
2416{
2417 if (safe_highmem_bm)
2418 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
2419
2420 if (buffer)
2421 free_image_page(buffer, PG_UNSAFE_CLEAR);
2422}
2423#else
2424static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
2425
2426static inline int prepare_highmem_image(struct memory_bitmap *bm,
2427 unsigned int *nr_highmem_p) { return 0; }
2428
2429static inline void *get_highmem_page_buffer(struct page *page,
2430 struct chain_allocator *ca)
2431{
2432 return ERR_PTR(-EINVAL);
2433}
2434
2435static inline void copy_last_highmem_page(void) {}
2436static inline int last_highmem_page_copied(void) { return 1; }
2437static inline void free_highmem_data(void) {}
2438#endif /* CONFIG_HIGHMEM */
2439
2440#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
2441
2442/**
2443 * prepare_image - Make room for loading hibernation image.
2444 * @new_bm: Unitialized memory bitmap structure.
2445 * @bm: Memory bitmap with unsafe pages marked.
2446 *
2447 * Use @bm to mark the pages that will be overwritten in the process of
2448 * restoring the system memory state from the suspend image ("unsafe" pages)
2449 * and allocate memory for the image.
2450 *
2451 * The idea is to allocate a new memory bitmap first and then allocate
2452 * as many pages as needed for image data, but without specifying what those
2453 * pages will be used for just yet. Instead, we mark them all as allocated and
2454 * create a lists of "safe" pages to be used later. On systems with high
2455 * memory a list of "safe" highmem pages is created too.
2456 */
2457static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
2458{
2459 unsigned int nr_pages, nr_highmem;
2460 struct linked_page *lp;
2461 int error;
2462
2463 /* If there is no highmem, the buffer will not be necessary */
2464 free_image_page(buffer, PG_UNSAFE_CLEAR);
2465 buffer = NULL;
2466
2467 nr_highmem = count_highmem_image_pages(bm);
2468 mark_unsafe_pages(bm);
2469
2470 error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
2471 if (error)
2472 goto Free;
2473
2474 duplicate_memory_bitmap(new_bm, bm);
2475 memory_bm_free(bm, PG_UNSAFE_KEEP);
2476 if (nr_highmem > 0) {
2477 error = prepare_highmem_image(bm, &nr_highmem);
2478 if (error)
2479 goto Free;
2480 }
2481 /*
2482 * Reserve some safe pages for potential later use.
2483 *
2484 * NOTE: This way we make sure there will be enough safe pages for the
2485 * chain_alloc() in get_buffer(). It is a bit wasteful, but
2486 * nr_copy_pages cannot be greater than 50% of the memory anyway.
2487 *
2488 * nr_copy_pages cannot be less than allocated_unsafe_pages too.
2489 */
2490 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2491 nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
2492 while (nr_pages > 0) {
2493 lp = get_image_page(GFP_ATOMIC, PG_SAFE);
2494 if (!lp) {
2495 error = -ENOMEM;
2496 goto Free;
2497 }
2498 lp->next = safe_pages_list;
2499 safe_pages_list = lp;
2500 nr_pages--;
2501 }
2502 /* Preallocate memory for the image */
2503 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2504 while (nr_pages > 0) {
2505 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
2506 if (!lp) {
2507 error = -ENOMEM;
2508 goto Free;
2509 }
2510 if (!swsusp_page_is_free(virt_to_page(lp))) {
2511 /* The page is "safe", add it to the list */
2512 lp->next = safe_pages_list;
2513 safe_pages_list = lp;
2514 }
2515 /* Mark the page as allocated */
2516 swsusp_set_page_forbidden(virt_to_page(lp));
2517 swsusp_set_page_free(virt_to_page(lp));
2518 nr_pages--;
2519 }
2520 return 0;
2521
2522 Free:
2523 swsusp_free();
2524 return error;
2525}
2526
2527/**
2528 * get_buffer - Get the address to store the next image data page.
2529 *
2530 * Get the address that snapshot_write_next() should return to its caller to
2531 * write to.
2532 */
2533static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
2534{
2535 struct pbe *pbe;
2536 struct page *page;
2537 unsigned long pfn = memory_bm_next_pfn(bm);
2538
2539 if (pfn == BM_END_OF_MAP)
2540 return ERR_PTR(-EFAULT);
2541
2542 page = pfn_to_page(pfn);
2543 if (PageHighMem(page))
2544 return get_highmem_page_buffer(page, ca);
2545
2546 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2547 /*
2548 * We have allocated the "original" page frame and we can
2549 * use it directly to store the loaded page.
2550 */
2551 return page_address(page);
2552
2553 /*
2554 * The "original" page frame has not been allocated and we have to
2555 * use a "safe" page frame to store the loaded page.
2556 */
2557 pbe = chain_alloc(ca, sizeof(struct pbe));
2558 if (!pbe) {
2559 swsusp_free();
2560 return ERR_PTR(-ENOMEM);
2561 }
2562 pbe->orig_address = page_address(page);
2563 pbe->address = safe_pages_list;
2564 safe_pages_list = safe_pages_list->next;
2565 pbe->next = restore_pblist;
2566 restore_pblist = pbe;
2567 return pbe->address;
2568}
2569
2570/**
2571 * snapshot_write_next - Get the address to store the next image page.
2572 * @handle: Snapshot handle structure to guide the writing.
2573 *
2574 * On the first call, @handle should point to a zeroed snapshot_handle
2575 * structure. The structure gets populated then and a pointer to it should be
2576 * passed to this function every next time.
2577 *
2578 * On success, the function returns a positive number. Then, the caller
2579 * is allowed to write up to the returned number of bytes to the memory
2580 * location computed by the data_of() macro.
2581 *
2582 * The function returns 0 to indicate the "end of file" condition. Negative
2583 * numbers are returned on errors, in which cases the structure pointed to by
2584 * @handle is not updated and should not be used any more.
2585 */
2586int snapshot_write_next(struct snapshot_handle *handle)
2587{
2588 static struct chain_allocator ca;
2589 int error = 0;
2590
2591 /* Check if we have already loaded the entire image */
2592 if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
2593 return 0;
2594
2595 handle->sync_read = 1;
2596
2597 if (!handle->cur) {
2598 if (!buffer)
2599 /* This makes the buffer be freed by swsusp_free() */
2600 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2601
2602 if (!buffer)
2603 return -ENOMEM;
2604
2605 handle->buffer = buffer;
2606 } else if (handle->cur == 1) {
2607 error = load_header(buffer);
2608 if (error)
2609 return error;
2610
2611 safe_pages_list = NULL;
2612
2613 error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
2614 if (error)
2615 return error;
2616
2617 hibernate_restore_protection_begin();
2618 } else if (handle->cur <= nr_meta_pages + 1) {
2619 error = unpack_orig_pfns(buffer, ©_bm);
2620 if (error)
2621 return error;
2622
2623 if (handle->cur == nr_meta_pages + 1) {
2624 error = prepare_image(&orig_bm, ©_bm);
2625 if (error)
2626 return error;
2627
2628 chain_init(&ca, GFP_ATOMIC, PG_SAFE);
2629 memory_bm_position_reset(&orig_bm);
2630 restore_pblist = NULL;
2631 handle->buffer = get_buffer(&orig_bm, &ca);
2632 handle->sync_read = 0;
2633 if (IS_ERR(handle->buffer))
2634 return PTR_ERR(handle->buffer);
2635 }
2636 } else {
2637 copy_last_highmem_page();
2638 hibernate_restore_protect_page(handle->buffer);
2639 handle->buffer = get_buffer(&orig_bm, &ca);
2640 if (IS_ERR(handle->buffer))
2641 return PTR_ERR(handle->buffer);
2642 if (handle->buffer != buffer)
2643 handle->sync_read = 0;
2644 }
2645 handle->cur++;
2646 return PAGE_SIZE;
2647}
2648
2649/**
2650 * snapshot_write_finalize - Complete the loading of a hibernation image.
2651 *
2652 * Must be called after the last call to snapshot_write_next() in case the last
2653 * page in the image happens to be a highmem page and its contents should be
2654 * stored in highmem. Additionally, it recycles bitmap memory that's not
2655 * necessary any more.
2656 */
2657void snapshot_write_finalize(struct snapshot_handle *handle)
2658{
2659 copy_last_highmem_page();
2660 hibernate_restore_protect_page(handle->buffer);
2661 /* Do that only if we have loaded the image entirely */
2662 if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
2663 memory_bm_recycle(&orig_bm);
2664 free_highmem_data();
2665 }
2666}
2667
2668int snapshot_image_loaded(struct snapshot_handle *handle)
2669{
2670 return !(!nr_copy_pages || !last_highmem_page_copied() ||
2671 handle->cur <= nr_meta_pages + nr_copy_pages);
2672}
2673
2674#ifdef CONFIG_HIGHMEM
2675/* Assumes that @buf is ready and points to a "safe" page */
2676static inline void swap_two_pages_data(struct page *p1, struct page *p2,
2677 void *buf)
2678{
2679 void *kaddr1, *kaddr2;
2680
2681 kaddr1 = kmap_atomic(p1);
2682 kaddr2 = kmap_atomic(p2);
2683 copy_page(buf, kaddr1);
2684 copy_page(kaddr1, kaddr2);
2685 copy_page(kaddr2, buf);
2686 kunmap_atomic(kaddr2);
2687 kunmap_atomic(kaddr1);
2688}
2689
2690/**
2691 * restore_highmem - Put highmem image pages into their original locations.
2692 *
2693 * For each highmem page that was in use before hibernation and is included in
2694 * the image, and also has been allocated by the "restore" kernel, swap its
2695 * current contents with the previous (ie. "before hibernation") ones.
2696 *
2697 * If the restore eventually fails, we can call this function once again and
2698 * restore the highmem state as seen by the restore kernel.
2699 */
2700int restore_highmem(void)
2701{
2702 struct highmem_pbe *pbe = highmem_pblist;
2703 void *buf;
2704
2705 if (!pbe)
2706 return 0;
2707
2708 buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2709 if (!buf)
2710 return -ENOMEM;
2711
2712 while (pbe) {
2713 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2714 pbe = pbe->next;
2715 }
2716 free_image_page(buf, PG_UNSAFE_CLEAR);
2717 return 0;
2718}
2719#endif /* CONFIG_HIGHMEM */
1/*
2 * linux/kernel/power/snapshot.c
3 *
4 * This file provides system snapshot/restore functionality for swsusp.
5 *
6 * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
7 * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
8 *
9 * This file is released under the GPLv2.
10 *
11 */
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/bootmem.h>
25#include <linux/syscalls.h>
26#include <linux/console.h>
27#include <linux/highmem.h>
28#include <linux/list.h>
29#include <linux/slab.h>
30
31#include <asm/uaccess.h>
32#include <asm/mmu_context.h>
33#include <asm/pgtable.h>
34#include <asm/tlbflush.h>
35#include <asm/io.h>
36
37#include "power.h"
38
39static int swsusp_page_is_free(struct page *);
40static void swsusp_set_page_forbidden(struct page *);
41static void swsusp_unset_page_forbidden(struct page *);
42
43/*
44 * Number of bytes to reserve for memory allocations made by device drivers
45 * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
46 * cause image creation to fail (tunable via /sys/power/reserved_size).
47 */
48unsigned long reserved_size;
49
50void __init hibernate_reserved_size_init(void)
51{
52 reserved_size = SPARE_PAGES * PAGE_SIZE;
53}
54
55/*
56 * Preferred image size in bytes (tunable via /sys/power/image_size).
57 * When it is set to N, swsusp will do its best to ensure the image
58 * size will not exceed N bytes, but if that is impossible, it will
59 * try to create the smallest image possible.
60 */
61unsigned long image_size;
62
63void __init hibernate_image_size_init(void)
64{
65 image_size = ((totalram_pages * 2) / 5) * PAGE_SIZE;
66}
67
68/* List of PBEs needed for restoring the pages that were allocated before
69 * the suspend and included in the suspend image, but have also been
70 * allocated by the "resume" kernel, so their contents cannot be written
71 * directly to their "original" page frames.
72 */
73struct pbe *restore_pblist;
74
75/* Pointer to an auxiliary buffer (1 page) */
76static void *buffer;
77
78/**
79 * @safe_needed - on resume, for storing the PBE list and the image,
80 * we can only use memory pages that do not conflict with the pages
81 * used before suspend. The unsafe pages have PageNosaveFree set
82 * and we count them using unsafe_pages.
83 *
84 * Each allocated image page is marked as PageNosave and PageNosaveFree
85 * so that swsusp_free() can release it.
86 */
87
88#define PG_ANY 0
89#define PG_SAFE 1
90#define PG_UNSAFE_CLEAR 1
91#define PG_UNSAFE_KEEP 0
92
93static unsigned int allocated_unsafe_pages;
94
95static void *get_image_page(gfp_t gfp_mask, int safe_needed)
96{
97 void *res;
98
99 res = (void *)get_zeroed_page(gfp_mask);
100 if (safe_needed)
101 while (res && swsusp_page_is_free(virt_to_page(res))) {
102 /* The page is unsafe, mark it for swsusp_free() */
103 swsusp_set_page_forbidden(virt_to_page(res));
104 allocated_unsafe_pages++;
105 res = (void *)get_zeroed_page(gfp_mask);
106 }
107 if (res) {
108 swsusp_set_page_forbidden(virt_to_page(res));
109 swsusp_set_page_free(virt_to_page(res));
110 }
111 return res;
112}
113
114unsigned long get_safe_page(gfp_t gfp_mask)
115{
116 return (unsigned long)get_image_page(gfp_mask, PG_SAFE);
117}
118
119static struct page *alloc_image_page(gfp_t gfp_mask)
120{
121 struct page *page;
122
123 page = alloc_page(gfp_mask);
124 if (page) {
125 swsusp_set_page_forbidden(page);
126 swsusp_set_page_free(page);
127 }
128 return page;
129}
130
131/**
132 * free_image_page - free page represented by @addr, allocated with
133 * get_image_page (page flags set by it must be cleared)
134 */
135
136static inline void free_image_page(void *addr, int clear_nosave_free)
137{
138 struct page *page;
139
140 BUG_ON(!virt_addr_valid(addr));
141
142 page = virt_to_page(addr);
143
144 swsusp_unset_page_forbidden(page);
145 if (clear_nosave_free)
146 swsusp_unset_page_free(page);
147
148 __free_page(page);
149}
150
151/* struct linked_page is used to build chains of pages */
152
153#define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *))
154
155struct linked_page {
156 struct linked_page *next;
157 char data[LINKED_PAGE_DATA_SIZE];
158} __attribute__((packed));
159
160static inline void
161free_list_of_pages(struct linked_page *list, int clear_page_nosave)
162{
163 while (list) {
164 struct linked_page *lp = list->next;
165
166 free_image_page(list, clear_page_nosave);
167 list = lp;
168 }
169}
170
171/**
172 * struct chain_allocator is used for allocating small objects out of
173 * a linked list of pages called 'the chain'.
174 *
175 * The chain grows each time when there is no room for a new object in
176 * the current page. The allocated objects cannot be freed individually.
177 * It is only possible to free them all at once, by freeing the entire
178 * chain.
179 *
180 * NOTE: The chain allocator may be inefficient if the allocated objects
181 * are not much smaller than PAGE_SIZE.
182 */
183
184struct chain_allocator {
185 struct linked_page *chain; /* the chain */
186 unsigned int used_space; /* total size of objects allocated out
187 * of the current page
188 */
189 gfp_t gfp_mask; /* mask for allocating pages */
190 int safe_needed; /* if set, only "safe" pages are allocated */
191};
192
193static void
194chain_init(struct chain_allocator *ca, gfp_t gfp_mask, int safe_needed)
195{
196 ca->chain = NULL;
197 ca->used_space = LINKED_PAGE_DATA_SIZE;
198 ca->gfp_mask = gfp_mask;
199 ca->safe_needed = safe_needed;
200}
201
202static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
203{
204 void *ret;
205
206 if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
207 struct linked_page *lp;
208
209 lp = get_image_page(ca->gfp_mask, ca->safe_needed);
210 if (!lp)
211 return NULL;
212
213 lp->next = ca->chain;
214 ca->chain = lp;
215 ca->used_space = 0;
216 }
217 ret = ca->chain->data + ca->used_space;
218 ca->used_space += size;
219 return ret;
220}
221
222/**
223 * Data types related to memory bitmaps.
224 *
225 * Memory bitmap is a structure consiting of many linked lists of
226 * objects. The main list's elements are of type struct zone_bitmap
227 * and each of them corresonds to one zone. For each zone bitmap
228 * object there is a list of objects of type struct bm_block that
229 * represent each blocks of bitmap in which information is stored.
230 *
231 * struct memory_bitmap contains a pointer to the main list of zone
232 * bitmap objects, a struct bm_position used for browsing the bitmap,
233 * and a pointer to the list of pages used for allocating all of the
234 * zone bitmap objects and bitmap block objects.
235 *
236 * NOTE: It has to be possible to lay out the bitmap in memory
237 * using only allocations of order 0. Additionally, the bitmap is
238 * designed to work with arbitrary number of zones (this is over the
239 * top for now, but let's avoid making unnecessary assumptions ;-).
240 *
241 * struct zone_bitmap contains a pointer to a list of bitmap block
242 * objects and a pointer to the bitmap block object that has been
243 * most recently used for setting bits. Additionally, it contains the
244 * pfns that correspond to the start and end of the represented zone.
245 *
246 * struct bm_block contains a pointer to the memory page in which
247 * information is stored (in the form of a block of bitmap)
248 * It also contains the pfns that correspond to the start and end of
249 * the represented memory area.
250 */
251
252#define BM_END_OF_MAP (~0UL)
253
254#define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE)
255
256struct bm_block {
257 struct list_head hook; /* hook into a list of bitmap blocks */
258 unsigned long start_pfn; /* pfn represented by the first bit */
259 unsigned long end_pfn; /* pfn represented by the last bit plus 1 */
260 unsigned long *data; /* bitmap representing pages */
261};
262
263static inline unsigned long bm_block_bits(struct bm_block *bb)
264{
265 return bb->end_pfn - bb->start_pfn;
266}
267
268/* strcut bm_position is used for browsing memory bitmaps */
269
270struct bm_position {
271 struct bm_block *block;
272 int bit;
273};
274
275struct memory_bitmap {
276 struct list_head blocks; /* list of bitmap blocks */
277 struct linked_page *p_list; /* list of pages used to store zone
278 * bitmap objects and bitmap block
279 * objects
280 */
281 struct bm_position cur; /* most recently used bit position */
282};
283
284/* Functions that operate on memory bitmaps */
285
286static void memory_bm_position_reset(struct memory_bitmap *bm)
287{
288 bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
289 bm->cur.bit = 0;
290}
291
292static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
293
294/**
295 * create_bm_block_list - create a list of block bitmap objects
296 * @pages - number of pages to track
297 * @list - list to put the allocated blocks into
298 * @ca - chain allocator to be used for allocating memory
299 */
300static int create_bm_block_list(unsigned long pages,
301 struct list_head *list,
302 struct chain_allocator *ca)
303{
304 unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
305
306 while (nr_blocks-- > 0) {
307 struct bm_block *bb;
308
309 bb = chain_alloc(ca, sizeof(struct bm_block));
310 if (!bb)
311 return -ENOMEM;
312 list_add(&bb->hook, list);
313 }
314
315 return 0;
316}
317
318struct mem_extent {
319 struct list_head hook;
320 unsigned long start;
321 unsigned long end;
322};
323
324/**
325 * free_mem_extents - free a list of memory extents
326 * @list - list of extents to empty
327 */
328static void free_mem_extents(struct list_head *list)
329{
330 struct mem_extent *ext, *aux;
331
332 list_for_each_entry_safe(ext, aux, list, hook) {
333 list_del(&ext->hook);
334 kfree(ext);
335 }
336}
337
338/**
339 * create_mem_extents - create a list of memory extents representing
340 * contiguous ranges of PFNs
341 * @list - list to put the extents into
342 * @gfp_mask - mask to use for memory allocations
343 */
344static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
345{
346 struct zone *zone;
347
348 INIT_LIST_HEAD(list);
349
350 for_each_populated_zone(zone) {
351 unsigned long zone_start, zone_end;
352 struct mem_extent *ext, *cur, *aux;
353
354 zone_start = zone->zone_start_pfn;
355 zone_end = zone->zone_start_pfn + zone->spanned_pages;
356
357 list_for_each_entry(ext, list, hook)
358 if (zone_start <= ext->end)
359 break;
360
361 if (&ext->hook == list || zone_end < ext->start) {
362 /* New extent is necessary */
363 struct mem_extent *new_ext;
364
365 new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
366 if (!new_ext) {
367 free_mem_extents(list);
368 return -ENOMEM;
369 }
370 new_ext->start = zone_start;
371 new_ext->end = zone_end;
372 list_add_tail(&new_ext->hook, &ext->hook);
373 continue;
374 }
375
376 /* Merge this zone's range of PFNs with the existing one */
377 if (zone_start < ext->start)
378 ext->start = zone_start;
379 if (zone_end > ext->end)
380 ext->end = zone_end;
381
382 /* More merging may be possible */
383 cur = ext;
384 list_for_each_entry_safe_continue(cur, aux, list, hook) {
385 if (zone_end < cur->start)
386 break;
387 if (zone_end < cur->end)
388 ext->end = cur->end;
389 list_del(&cur->hook);
390 kfree(cur);
391 }
392 }
393
394 return 0;
395}
396
397/**
398 * memory_bm_create - allocate memory for a memory bitmap
399 */
400static int
401memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
402{
403 struct chain_allocator ca;
404 struct list_head mem_extents;
405 struct mem_extent *ext;
406 int error;
407
408 chain_init(&ca, gfp_mask, safe_needed);
409 INIT_LIST_HEAD(&bm->blocks);
410
411 error = create_mem_extents(&mem_extents, gfp_mask);
412 if (error)
413 return error;
414
415 list_for_each_entry(ext, &mem_extents, hook) {
416 struct bm_block *bb;
417 unsigned long pfn = ext->start;
418 unsigned long pages = ext->end - ext->start;
419
420 bb = list_entry(bm->blocks.prev, struct bm_block, hook);
421
422 error = create_bm_block_list(pages, bm->blocks.prev, &ca);
423 if (error)
424 goto Error;
425
426 list_for_each_entry_continue(bb, &bm->blocks, hook) {
427 bb->data = get_image_page(gfp_mask, safe_needed);
428 if (!bb->data) {
429 error = -ENOMEM;
430 goto Error;
431 }
432
433 bb->start_pfn = pfn;
434 if (pages >= BM_BITS_PER_BLOCK) {
435 pfn += BM_BITS_PER_BLOCK;
436 pages -= BM_BITS_PER_BLOCK;
437 } else {
438 /* This is executed only once in the loop */
439 pfn += pages;
440 }
441 bb->end_pfn = pfn;
442 }
443 }
444
445 bm->p_list = ca.chain;
446 memory_bm_position_reset(bm);
447 Exit:
448 free_mem_extents(&mem_extents);
449 return error;
450
451 Error:
452 bm->p_list = ca.chain;
453 memory_bm_free(bm, PG_UNSAFE_CLEAR);
454 goto Exit;
455}
456
457/**
458 * memory_bm_free - free memory occupied by the memory bitmap @bm
459 */
460static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
461{
462 struct bm_block *bb;
463
464 list_for_each_entry(bb, &bm->blocks, hook)
465 if (bb->data)
466 free_image_page(bb->data, clear_nosave_free);
467
468 free_list_of_pages(bm->p_list, clear_nosave_free);
469
470 INIT_LIST_HEAD(&bm->blocks);
471}
472
473/**
474 * memory_bm_find_bit - find the bit in the bitmap @bm that corresponds
475 * to given pfn. The cur_zone_bm member of @bm and the cur_block member
476 * of @bm->cur_zone_bm are updated.
477 */
478static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
479 void **addr, unsigned int *bit_nr)
480{
481 struct bm_block *bb;
482
483 /*
484 * Check if the pfn corresponds to the current bitmap block and find
485 * the block where it fits if this is not the case.
486 */
487 bb = bm->cur.block;
488 if (pfn < bb->start_pfn)
489 list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
490 if (pfn >= bb->start_pfn)
491 break;
492
493 if (pfn >= bb->end_pfn)
494 list_for_each_entry_continue(bb, &bm->blocks, hook)
495 if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
496 break;
497
498 if (&bb->hook == &bm->blocks)
499 return -EFAULT;
500
501 /* The block has been found */
502 bm->cur.block = bb;
503 pfn -= bb->start_pfn;
504 bm->cur.bit = pfn + 1;
505 *bit_nr = pfn;
506 *addr = bb->data;
507 return 0;
508}
509
510static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
511{
512 void *addr;
513 unsigned int bit;
514 int error;
515
516 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
517 BUG_ON(error);
518 set_bit(bit, addr);
519}
520
521static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
522{
523 void *addr;
524 unsigned int bit;
525 int error;
526
527 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
528 if (!error)
529 set_bit(bit, addr);
530 return error;
531}
532
533static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
534{
535 void *addr;
536 unsigned int bit;
537 int error;
538
539 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
540 BUG_ON(error);
541 clear_bit(bit, addr);
542}
543
544static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
545{
546 void *addr;
547 unsigned int bit;
548 int error;
549
550 error = memory_bm_find_bit(bm, pfn, &addr, &bit);
551 BUG_ON(error);
552 return test_bit(bit, addr);
553}
554
555static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
556{
557 void *addr;
558 unsigned int bit;
559
560 return !memory_bm_find_bit(bm, pfn, &addr, &bit);
561}
562
563/**
564 * memory_bm_next_pfn - find the pfn that corresponds to the next set bit
565 * in the bitmap @bm. If the pfn cannot be found, BM_END_OF_MAP is
566 * returned.
567 *
568 * It is required to run memory_bm_position_reset() before the first call to
569 * this function.
570 */
571
572static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
573{
574 struct bm_block *bb;
575 int bit;
576
577 bb = bm->cur.block;
578 do {
579 bit = bm->cur.bit;
580 bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
581 if (bit < bm_block_bits(bb))
582 goto Return_pfn;
583
584 bb = list_entry(bb->hook.next, struct bm_block, hook);
585 bm->cur.block = bb;
586 bm->cur.bit = 0;
587 } while (&bb->hook != &bm->blocks);
588
589 memory_bm_position_reset(bm);
590 return BM_END_OF_MAP;
591
592 Return_pfn:
593 bm->cur.bit = bit + 1;
594 return bb->start_pfn + bit;
595}
596
597/**
598 * This structure represents a range of page frames the contents of which
599 * should not be saved during the suspend.
600 */
601
602struct nosave_region {
603 struct list_head list;
604 unsigned long start_pfn;
605 unsigned long end_pfn;
606};
607
608static LIST_HEAD(nosave_regions);
609
610/**
611 * register_nosave_region - register a range of page frames the contents
612 * of which should not be saved during the suspend (to be used in the early
613 * initialization code)
614 */
615
616void __init
617__register_nosave_region(unsigned long start_pfn, unsigned long end_pfn,
618 int use_kmalloc)
619{
620 struct nosave_region *region;
621
622 if (start_pfn >= end_pfn)
623 return;
624
625 if (!list_empty(&nosave_regions)) {
626 /* Try to extend the previous region (they should be sorted) */
627 region = list_entry(nosave_regions.prev,
628 struct nosave_region, list);
629 if (region->end_pfn == start_pfn) {
630 region->end_pfn = end_pfn;
631 goto Report;
632 }
633 }
634 if (use_kmalloc) {
635 /* during init, this shouldn't fail */
636 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
637 BUG_ON(!region);
638 } else
639 /* This allocation cannot fail */
640 region = alloc_bootmem(sizeof(struct nosave_region));
641 region->start_pfn = start_pfn;
642 region->end_pfn = end_pfn;
643 list_add_tail(®ion->list, &nosave_regions);
644 Report:
645 printk(KERN_INFO "PM: Registered nosave memory: %016lx - %016lx\n",
646 start_pfn << PAGE_SHIFT, end_pfn << PAGE_SHIFT);
647}
648
649/*
650 * Set bits in this map correspond to the page frames the contents of which
651 * should not be saved during the suspend.
652 */
653static struct memory_bitmap *forbidden_pages_map;
654
655/* Set bits in this map correspond to free page frames. */
656static struct memory_bitmap *free_pages_map;
657
658/*
659 * Each page frame allocated for creating the image is marked by setting the
660 * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
661 */
662
663void swsusp_set_page_free(struct page *page)
664{
665 if (free_pages_map)
666 memory_bm_set_bit(free_pages_map, page_to_pfn(page));
667}
668
669static int swsusp_page_is_free(struct page *page)
670{
671 return free_pages_map ?
672 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
673}
674
675void swsusp_unset_page_free(struct page *page)
676{
677 if (free_pages_map)
678 memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
679}
680
681static void swsusp_set_page_forbidden(struct page *page)
682{
683 if (forbidden_pages_map)
684 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
685}
686
687int swsusp_page_is_forbidden(struct page *page)
688{
689 return forbidden_pages_map ?
690 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
691}
692
693static void swsusp_unset_page_forbidden(struct page *page)
694{
695 if (forbidden_pages_map)
696 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
697}
698
699/**
700 * mark_nosave_pages - set bits corresponding to the page frames the
701 * contents of which should not be saved in a given bitmap.
702 */
703
704static void mark_nosave_pages(struct memory_bitmap *bm)
705{
706 struct nosave_region *region;
707
708 if (list_empty(&nosave_regions))
709 return;
710
711 list_for_each_entry(region, &nosave_regions, list) {
712 unsigned long pfn;
713
714 pr_debug("PM: Marking nosave pages: [mem %#010llx-%#010llx]\n",
715 (unsigned long long) region->start_pfn << PAGE_SHIFT,
716 ((unsigned long long) region->end_pfn << PAGE_SHIFT)
717 - 1);
718
719 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
720 if (pfn_valid(pfn)) {
721 /*
722 * It is safe to ignore the result of
723 * mem_bm_set_bit_check() here, since we won't
724 * touch the PFNs for which the error is
725 * returned anyway.
726 */
727 mem_bm_set_bit_check(bm, pfn);
728 }
729 }
730}
731
732/**
733 * create_basic_memory_bitmaps - create bitmaps needed for marking page
734 * frames that should not be saved and free page frames. The pointers
735 * forbidden_pages_map and free_pages_map are only modified if everything
736 * goes well, because we don't want the bits to be used before both bitmaps
737 * are set up.
738 */
739
740int create_basic_memory_bitmaps(void)
741{
742 struct memory_bitmap *bm1, *bm2;
743 int error = 0;
744
745 BUG_ON(forbidden_pages_map || free_pages_map);
746
747 bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
748 if (!bm1)
749 return -ENOMEM;
750
751 error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
752 if (error)
753 goto Free_first_object;
754
755 bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
756 if (!bm2)
757 goto Free_first_bitmap;
758
759 error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
760 if (error)
761 goto Free_second_object;
762
763 forbidden_pages_map = bm1;
764 free_pages_map = bm2;
765 mark_nosave_pages(forbidden_pages_map);
766
767 pr_debug("PM: Basic memory bitmaps created\n");
768
769 return 0;
770
771 Free_second_object:
772 kfree(bm2);
773 Free_first_bitmap:
774 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
775 Free_first_object:
776 kfree(bm1);
777 return -ENOMEM;
778}
779
780/**
781 * free_basic_memory_bitmaps - free memory bitmaps allocated by
782 * create_basic_memory_bitmaps(). The auxiliary pointers are necessary
783 * so that the bitmaps themselves are not referred to while they are being
784 * freed.
785 */
786
787void free_basic_memory_bitmaps(void)
788{
789 struct memory_bitmap *bm1, *bm2;
790
791 BUG_ON(!(forbidden_pages_map && free_pages_map));
792
793 bm1 = forbidden_pages_map;
794 bm2 = free_pages_map;
795 forbidden_pages_map = NULL;
796 free_pages_map = NULL;
797 memory_bm_free(bm1, PG_UNSAFE_CLEAR);
798 kfree(bm1);
799 memory_bm_free(bm2, PG_UNSAFE_CLEAR);
800 kfree(bm2);
801
802 pr_debug("PM: Basic memory bitmaps freed\n");
803}
804
805/**
806 * snapshot_additional_pages - estimate the number of additional pages
807 * be needed for setting up the suspend image data structures for given
808 * zone (usually the returned value is greater than the exact number)
809 */
810
811unsigned int snapshot_additional_pages(struct zone *zone)
812{
813 unsigned int res;
814
815 res = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
816 res += DIV_ROUND_UP(res * sizeof(struct bm_block),
817 LINKED_PAGE_DATA_SIZE);
818 return 2 * res;
819}
820
821#ifdef CONFIG_HIGHMEM
822/**
823 * count_free_highmem_pages - compute the total number of free highmem
824 * pages, system-wide.
825 */
826
827static unsigned int count_free_highmem_pages(void)
828{
829 struct zone *zone;
830 unsigned int cnt = 0;
831
832 for_each_populated_zone(zone)
833 if (is_highmem(zone))
834 cnt += zone_page_state(zone, NR_FREE_PAGES);
835
836 return cnt;
837}
838
839/**
840 * saveable_highmem_page - Determine whether a highmem page should be
841 * included in the suspend image.
842 *
843 * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
844 * and it isn't a part of a free chunk of pages.
845 */
846static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
847{
848 struct page *page;
849
850 if (!pfn_valid(pfn))
851 return NULL;
852
853 page = pfn_to_page(pfn);
854 if (page_zone(page) != zone)
855 return NULL;
856
857 BUG_ON(!PageHighMem(page));
858
859 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page) ||
860 PageReserved(page))
861 return NULL;
862
863 if (page_is_guard(page))
864 return NULL;
865
866 return page;
867}
868
869/**
870 * count_highmem_pages - compute the total number of saveable highmem
871 * pages.
872 */
873
874static unsigned int count_highmem_pages(void)
875{
876 struct zone *zone;
877 unsigned int n = 0;
878
879 for_each_populated_zone(zone) {
880 unsigned long pfn, max_zone_pfn;
881
882 if (!is_highmem(zone))
883 continue;
884
885 mark_free_pages(zone);
886 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
887 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
888 if (saveable_highmem_page(zone, pfn))
889 n++;
890 }
891 return n;
892}
893#else
894static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
895{
896 return NULL;
897}
898#endif /* CONFIG_HIGHMEM */
899
900/**
901 * saveable_page - Determine whether a non-highmem page should be included
902 * in the suspend image.
903 *
904 * We should save the page if it isn't Nosave, and is not in the range
905 * of pages statically defined as 'unsaveable', and it isn't a part of
906 * a free chunk of pages.
907 */
908static struct page *saveable_page(struct zone *zone, unsigned long pfn)
909{
910 struct page *page;
911
912 if (!pfn_valid(pfn))
913 return NULL;
914
915 page = pfn_to_page(pfn);
916 if (page_zone(page) != zone)
917 return NULL;
918
919 BUG_ON(PageHighMem(page));
920
921 if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
922 return NULL;
923
924 if (PageReserved(page)
925 && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
926 return NULL;
927
928 if (page_is_guard(page))
929 return NULL;
930
931 return page;
932}
933
934/**
935 * count_data_pages - compute the total number of saveable non-highmem
936 * pages.
937 */
938
939static unsigned int count_data_pages(void)
940{
941 struct zone *zone;
942 unsigned long pfn, max_zone_pfn;
943 unsigned int n = 0;
944
945 for_each_populated_zone(zone) {
946 if (is_highmem(zone))
947 continue;
948
949 mark_free_pages(zone);
950 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
951 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
952 if (saveable_page(zone, pfn))
953 n++;
954 }
955 return n;
956}
957
958/* This is needed, because copy_page and memcpy are not usable for copying
959 * task structs.
960 */
961static inline void do_copy_page(long *dst, long *src)
962{
963 int n;
964
965 for (n = PAGE_SIZE / sizeof(long); n; n--)
966 *dst++ = *src++;
967}
968
969
970/**
971 * safe_copy_page - check if the page we are going to copy is marked as
972 * present in the kernel page tables (this always is the case if
973 * CONFIG_DEBUG_PAGEALLOC is not set and in that case
974 * kernel_page_present() always returns 'true').
975 */
976static void safe_copy_page(void *dst, struct page *s_page)
977{
978 if (kernel_page_present(s_page)) {
979 do_copy_page(dst, page_address(s_page));
980 } else {
981 kernel_map_pages(s_page, 1, 1);
982 do_copy_page(dst, page_address(s_page));
983 kernel_map_pages(s_page, 1, 0);
984 }
985}
986
987
988#ifdef CONFIG_HIGHMEM
989static inline struct page *
990page_is_saveable(struct zone *zone, unsigned long pfn)
991{
992 return is_highmem(zone) ?
993 saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
994}
995
996static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
997{
998 struct page *s_page, *d_page;
999 void *src, *dst;
1000
1001 s_page = pfn_to_page(src_pfn);
1002 d_page = pfn_to_page(dst_pfn);
1003 if (PageHighMem(s_page)) {
1004 src = kmap_atomic(s_page);
1005 dst = kmap_atomic(d_page);
1006 do_copy_page(dst, src);
1007 kunmap_atomic(dst);
1008 kunmap_atomic(src);
1009 } else {
1010 if (PageHighMem(d_page)) {
1011 /* Page pointed to by src may contain some kernel
1012 * data modified by kmap_atomic()
1013 */
1014 safe_copy_page(buffer, s_page);
1015 dst = kmap_atomic(d_page);
1016 copy_page(dst, buffer);
1017 kunmap_atomic(dst);
1018 } else {
1019 safe_copy_page(page_address(d_page), s_page);
1020 }
1021 }
1022}
1023#else
1024#define page_is_saveable(zone, pfn) saveable_page(zone, pfn)
1025
1026static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1027{
1028 safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1029 pfn_to_page(src_pfn));
1030}
1031#endif /* CONFIG_HIGHMEM */
1032
1033static void
1034copy_data_pages(struct memory_bitmap *copy_bm, struct memory_bitmap *orig_bm)
1035{
1036 struct zone *zone;
1037 unsigned long pfn;
1038
1039 for_each_populated_zone(zone) {
1040 unsigned long max_zone_pfn;
1041
1042 mark_free_pages(zone);
1043 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1044 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1045 if (page_is_saveable(zone, pfn))
1046 memory_bm_set_bit(orig_bm, pfn);
1047 }
1048 memory_bm_position_reset(orig_bm);
1049 memory_bm_position_reset(copy_bm);
1050 for(;;) {
1051 pfn = memory_bm_next_pfn(orig_bm);
1052 if (unlikely(pfn == BM_END_OF_MAP))
1053 break;
1054 copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
1055 }
1056}
1057
1058/* Total number of image pages */
1059static unsigned int nr_copy_pages;
1060/* Number of pages needed for saving the original pfns of the image pages */
1061static unsigned int nr_meta_pages;
1062/*
1063 * Numbers of normal and highmem page frames allocated for hibernation image
1064 * before suspending devices.
1065 */
1066unsigned int alloc_normal, alloc_highmem;
1067/*
1068 * Memory bitmap used for marking saveable pages (during hibernation) or
1069 * hibernation image pages (during restore)
1070 */
1071static struct memory_bitmap orig_bm;
1072/*
1073 * Memory bitmap used during hibernation for marking allocated page frames that
1074 * will contain copies of saveable pages. During restore it is initially used
1075 * for marking hibernation image pages, but then the set bits from it are
1076 * duplicated in @orig_bm and it is released. On highmem systems it is next
1077 * used for marking "safe" highmem pages, but it has to be reinitialized for
1078 * this purpose.
1079 */
1080static struct memory_bitmap copy_bm;
1081
1082/**
1083 * swsusp_free - free pages allocated for the suspend.
1084 *
1085 * Suspend pages are alocated before the atomic copy is made, so we
1086 * need to release them after the resume.
1087 */
1088
1089void swsusp_free(void)
1090{
1091 struct zone *zone;
1092 unsigned long pfn, max_zone_pfn;
1093
1094 for_each_populated_zone(zone) {
1095 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1096 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1097 if (pfn_valid(pfn)) {
1098 struct page *page = pfn_to_page(pfn);
1099
1100 if (swsusp_page_is_forbidden(page) &&
1101 swsusp_page_is_free(page)) {
1102 swsusp_unset_page_forbidden(page);
1103 swsusp_unset_page_free(page);
1104 __free_page(page);
1105 }
1106 }
1107 }
1108 nr_copy_pages = 0;
1109 nr_meta_pages = 0;
1110 restore_pblist = NULL;
1111 buffer = NULL;
1112 alloc_normal = 0;
1113 alloc_highmem = 0;
1114}
1115
1116/* Helper functions used for the shrinking of memory. */
1117
1118#define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN)
1119
1120/**
1121 * preallocate_image_pages - Allocate a number of pages for hibernation image
1122 * @nr_pages: Number of page frames to allocate.
1123 * @mask: GFP flags to use for the allocation.
1124 *
1125 * Return value: Number of page frames actually allocated
1126 */
1127static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1128{
1129 unsigned long nr_alloc = 0;
1130
1131 while (nr_pages > 0) {
1132 struct page *page;
1133
1134 page = alloc_image_page(mask);
1135 if (!page)
1136 break;
1137 memory_bm_set_bit(©_bm, page_to_pfn(page));
1138 if (PageHighMem(page))
1139 alloc_highmem++;
1140 else
1141 alloc_normal++;
1142 nr_pages--;
1143 nr_alloc++;
1144 }
1145
1146 return nr_alloc;
1147}
1148
1149static unsigned long preallocate_image_memory(unsigned long nr_pages,
1150 unsigned long avail_normal)
1151{
1152 unsigned long alloc;
1153
1154 if (avail_normal <= alloc_normal)
1155 return 0;
1156
1157 alloc = avail_normal - alloc_normal;
1158 if (nr_pages < alloc)
1159 alloc = nr_pages;
1160
1161 return preallocate_image_pages(alloc, GFP_IMAGE);
1162}
1163
1164#ifdef CONFIG_HIGHMEM
1165static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1166{
1167 return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1168}
1169
1170/**
1171 * __fraction - Compute (an approximation of) x * (multiplier / base)
1172 */
1173static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1174{
1175 x *= multiplier;
1176 do_div(x, base);
1177 return (unsigned long)x;
1178}
1179
1180static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1181 unsigned long highmem,
1182 unsigned long total)
1183{
1184 unsigned long alloc = __fraction(nr_pages, highmem, total);
1185
1186 return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1187}
1188#else /* CONFIG_HIGHMEM */
1189static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1190{
1191 return 0;
1192}
1193
1194static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1195 unsigned long highmem,
1196 unsigned long total)
1197{
1198 return 0;
1199}
1200#endif /* CONFIG_HIGHMEM */
1201
1202/**
1203 * free_unnecessary_pages - Release preallocated pages not needed for the image
1204 */
1205static void free_unnecessary_pages(void)
1206{
1207 unsigned long save, to_free_normal, to_free_highmem;
1208
1209 save = count_data_pages();
1210 if (alloc_normal >= save) {
1211 to_free_normal = alloc_normal - save;
1212 save = 0;
1213 } else {
1214 to_free_normal = 0;
1215 save -= alloc_normal;
1216 }
1217 save += count_highmem_pages();
1218 if (alloc_highmem >= save) {
1219 to_free_highmem = alloc_highmem - save;
1220 } else {
1221 to_free_highmem = 0;
1222 save -= alloc_highmem;
1223 if (to_free_normal > save)
1224 to_free_normal -= save;
1225 else
1226 to_free_normal = 0;
1227 }
1228
1229 memory_bm_position_reset(©_bm);
1230
1231 while (to_free_normal > 0 || to_free_highmem > 0) {
1232 unsigned long pfn = memory_bm_next_pfn(©_bm);
1233 struct page *page = pfn_to_page(pfn);
1234
1235 if (PageHighMem(page)) {
1236 if (!to_free_highmem)
1237 continue;
1238 to_free_highmem--;
1239 alloc_highmem--;
1240 } else {
1241 if (!to_free_normal)
1242 continue;
1243 to_free_normal--;
1244 alloc_normal--;
1245 }
1246 memory_bm_clear_bit(©_bm, pfn);
1247 swsusp_unset_page_forbidden(page);
1248 swsusp_unset_page_free(page);
1249 __free_page(page);
1250 }
1251}
1252
1253/**
1254 * minimum_image_size - Estimate the minimum acceptable size of an image
1255 * @saveable: Number of saveable pages in the system.
1256 *
1257 * We want to avoid attempting to free too much memory too hard, so estimate the
1258 * minimum acceptable size of a hibernation image to use as the lower limit for
1259 * preallocating memory.
1260 *
1261 * We assume that the minimum image size should be proportional to
1262 *
1263 * [number of saveable pages] - [number of pages that can be freed in theory]
1264 *
1265 * where the second term is the sum of (1) reclaimable slab pages, (2) active
1266 * and (3) inactive anonymouns pages, (4) active and (5) inactive file pages,
1267 * minus mapped file pages.
1268 */
1269static unsigned long minimum_image_size(unsigned long saveable)
1270{
1271 unsigned long size;
1272
1273 size = global_page_state(NR_SLAB_RECLAIMABLE)
1274 + global_page_state(NR_ACTIVE_ANON)
1275 + global_page_state(NR_INACTIVE_ANON)
1276 + global_page_state(NR_ACTIVE_FILE)
1277 + global_page_state(NR_INACTIVE_FILE)
1278 - global_page_state(NR_FILE_MAPPED);
1279
1280 return saveable <= size ? 0 : saveable - size;
1281}
1282
1283/**
1284 * hibernate_preallocate_memory - Preallocate memory for hibernation image
1285 *
1286 * To create a hibernation image it is necessary to make a copy of every page
1287 * frame in use. We also need a number of page frames to be free during
1288 * hibernation for allocations made while saving the image and for device
1289 * drivers, in case they need to allocate memory from their hibernation
1290 * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
1291 * estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through
1292 * /sys/power/reserved_size, respectively). To make this happen, we compute the
1293 * total number of available page frames and allocate at least
1294 *
1295 * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2
1296 * + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
1297 *
1298 * of them, which corresponds to the maximum size of a hibernation image.
1299 *
1300 * If image_size is set below the number following from the above formula,
1301 * the preallocation of memory is continued until the total number of saveable
1302 * pages in the system is below the requested image size or the minimum
1303 * acceptable image size returned by minimum_image_size(), whichever is greater.
1304 */
1305int hibernate_preallocate_memory(void)
1306{
1307 struct zone *zone;
1308 unsigned long saveable, size, max_size, count, highmem, pages = 0;
1309 unsigned long alloc, save_highmem, pages_highmem, avail_normal;
1310 struct timeval start, stop;
1311 int error;
1312
1313 printk(KERN_INFO "PM: Preallocating image memory... ");
1314 do_gettimeofday(&start);
1315
1316 error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
1317 if (error)
1318 goto err_out;
1319
1320 error = memory_bm_create(©_bm, GFP_IMAGE, PG_ANY);
1321 if (error)
1322 goto err_out;
1323
1324 alloc_normal = 0;
1325 alloc_highmem = 0;
1326
1327 /* Count the number of saveable data pages. */
1328 save_highmem = count_highmem_pages();
1329 saveable = count_data_pages();
1330
1331 /*
1332 * Compute the total number of page frames we can use (count) and the
1333 * number of pages needed for image metadata (size).
1334 */
1335 count = saveable;
1336 saveable += save_highmem;
1337 highmem = save_highmem;
1338 size = 0;
1339 for_each_populated_zone(zone) {
1340 size += snapshot_additional_pages(zone);
1341 if (is_highmem(zone))
1342 highmem += zone_page_state(zone, NR_FREE_PAGES);
1343 else
1344 count += zone_page_state(zone, NR_FREE_PAGES);
1345 }
1346 avail_normal = count;
1347 count += highmem;
1348 count -= totalreserve_pages;
1349
1350 /* Add number of pages required for page keys (s390 only). */
1351 size += page_key_additional_pages(saveable);
1352
1353 /* Compute the maximum number of saveable pages to leave in memory. */
1354 max_size = (count - (size + PAGES_FOR_IO)) / 2
1355 - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
1356 /* Compute the desired number of image pages specified by image_size. */
1357 size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1358 if (size > max_size)
1359 size = max_size;
1360 /*
1361 * If the desired number of image pages is at least as large as the
1362 * current number of saveable pages in memory, allocate page frames for
1363 * the image and we're done.
1364 */
1365 if (size >= saveable) {
1366 pages = preallocate_image_highmem(save_highmem);
1367 pages += preallocate_image_memory(saveable - pages, avail_normal);
1368 goto out;
1369 }
1370
1371 /* Estimate the minimum size of the image. */
1372 pages = minimum_image_size(saveable);
1373 /*
1374 * To avoid excessive pressure on the normal zone, leave room in it to
1375 * accommodate an image of the minimum size (unless it's already too
1376 * small, in which case don't preallocate pages from it at all).
1377 */
1378 if (avail_normal > pages)
1379 avail_normal -= pages;
1380 else
1381 avail_normal = 0;
1382 if (size < pages)
1383 size = min_t(unsigned long, pages, max_size);
1384
1385 /*
1386 * Let the memory management subsystem know that we're going to need a
1387 * large number of page frames to allocate and make it free some memory.
1388 * NOTE: If this is not done, performance will be hurt badly in some
1389 * test cases.
1390 */
1391 shrink_all_memory(saveable - size);
1392
1393 /*
1394 * The number of saveable pages in memory was too high, so apply some
1395 * pressure to decrease it. First, make room for the largest possible
1396 * image and fail if that doesn't work. Next, try to decrease the size
1397 * of the image as much as indicated by 'size' using allocations from
1398 * highmem and non-highmem zones separately.
1399 */
1400 pages_highmem = preallocate_image_highmem(highmem / 2);
1401 alloc = (count - max_size) - pages_highmem;
1402 pages = preallocate_image_memory(alloc, avail_normal);
1403 if (pages < alloc) {
1404 /* We have exhausted non-highmem pages, try highmem. */
1405 alloc -= pages;
1406 pages += pages_highmem;
1407 pages_highmem = preallocate_image_highmem(alloc);
1408 if (pages_highmem < alloc)
1409 goto err_out;
1410 pages += pages_highmem;
1411 /*
1412 * size is the desired number of saveable pages to leave in
1413 * memory, so try to preallocate (all memory - size) pages.
1414 */
1415 alloc = (count - pages) - size;
1416 pages += preallocate_image_highmem(alloc);
1417 } else {
1418 /*
1419 * There are approximately max_size saveable pages at this point
1420 * and we want to reduce this number down to size.
1421 */
1422 alloc = max_size - size;
1423 size = preallocate_highmem_fraction(alloc, highmem, count);
1424 pages_highmem += size;
1425 alloc -= size;
1426 size = preallocate_image_memory(alloc, avail_normal);
1427 pages_highmem += preallocate_image_highmem(alloc - size);
1428 pages += pages_highmem + size;
1429 }
1430
1431 /*
1432 * We only need as many page frames for the image as there are saveable
1433 * pages in memory, but we have allocated more. Release the excessive
1434 * ones now.
1435 */
1436 free_unnecessary_pages();
1437
1438 out:
1439 do_gettimeofday(&stop);
1440 printk(KERN_CONT "done (allocated %lu pages)\n", pages);
1441 swsusp_show_speed(&start, &stop, pages, "Allocated");
1442
1443 return 0;
1444
1445 err_out:
1446 printk(KERN_CONT "\n");
1447 swsusp_free();
1448 return -ENOMEM;
1449}
1450
1451#ifdef CONFIG_HIGHMEM
1452/**
1453 * count_pages_for_highmem - compute the number of non-highmem pages
1454 * that will be necessary for creating copies of highmem pages.
1455 */
1456
1457static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
1458{
1459 unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
1460
1461 if (free_highmem >= nr_highmem)
1462 nr_highmem = 0;
1463 else
1464 nr_highmem -= free_highmem;
1465
1466 return nr_highmem;
1467}
1468#else
1469static unsigned int
1470count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
1471#endif /* CONFIG_HIGHMEM */
1472
1473/**
1474 * enough_free_mem - Make sure we have enough free memory for the
1475 * snapshot image.
1476 */
1477
1478static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
1479{
1480 struct zone *zone;
1481 unsigned int free = alloc_normal;
1482
1483 for_each_populated_zone(zone)
1484 if (!is_highmem(zone))
1485 free += zone_page_state(zone, NR_FREE_PAGES);
1486
1487 nr_pages += count_pages_for_highmem(nr_highmem);
1488 pr_debug("PM: Normal pages needed: %u + %u, available pages: %u\n",
1489 nr_pages, PAGES_FOR_IO, free);
1490
1491 return free > nr_pages + PAGES_FOR_IO;
1492}
1493
1494#ifdef CONFIG_HIGHMEM
1495/**
1496 * get_highmem_buffer - if there are some highmem pages in the suspend
1497 * image, we may need the buffer to copy them and/or load their data.
1498 */
1499
1500static inline int get_highmem_buffer(int safe_needed)
1501{
1502 buffer = get_image_page(GFP_ATOMIC | __GFP_COLD, safe_needed);
1503 return buffer ? 0 : -ENOMEM;
1504}
1505
1506/**
1507 * alloc_highmem_image_pages - allocate some highmem pages for the image.
1508 * Try to allocate as many pages as needed, but if the number of free
1509 * highmem pages is lesser than that, allocate them all.
1510 */
1511
1512static inline unsigned int
1513alloc_highmem_pages(struct memory_bitmap *bm, unsigned int nr_highmem)
1514{
1515 unsigned int to_alloc = count_free_highmem_pages();
1516
1517 if (to_alloc > nr_highmem)
1518 to_alloc = nr_highmem;
1519
1520 nr_highmem -= to_alloc;
1521 while (to_alloc-- > 0) {
1522 struct page *page;
1523
1524 page = alloc_image_page(__GFP_HIGHMEM);
1525 memory_bm_set_bit(bm, page_to_pfn(page));
1526 }
1527 return nr_highmem;
1528}
1529#else
1530static inline int get_highmem_buffer(int safe_needed) { return 0; }
1531
1532static inline unsigned int
1533alloc_highmem_pages(struct memory_bitmap *bm, unsigned int n) { return 0; }
1534#endif /* CONFIG_HIGHMEM */
1535
1536/**
1537 * swsusp_alloc - allocate memory for the suspend image
1538 *
1539 * We first try to allocate as many highmem pages as there are
1540 * saveable highmem pages in the system. If that fails, we allocate
1541 * non-highmem pages for the copies of the remaining highmem ones.
1542 *
1543 * In this approach it is likely that the copies of highmem pages will
1544 * also be located in the high memory, because of the way in which
1545 * copy_data_pages() works.
1546 */
1547
1548static int
1549swsusp_alloc(struct memory_bitmap *orig_bm, struct memory_bitmap *copy_bm,
1550 unsigned int nr_pages, unsigned int nr_highmem)
1551{
1552 if (nr_highmem > 0) {
1553 if (get_highmem_buffer(PG_ANY))
1554 goto err_out;
1555 if (nr_highmem > alloc_highmem) {
1556 nr_highmem -= alloc_highmem;
1557 nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
1558 }
1559 }
1560 if (nr_pages > alloc_normal) {
1561 nr_pages -= alloc_normal;
1562 while (nr_pages-- > 0) {
1563 struct page *page;
1564
1565 page = alloc_image_page(GFP_ATOMIC | __GFP_COLD);
1566 if (!page)
1567 goto err_out;
1568 memory_bm_set_bit(copy_bm, page_to_pfn(page));
1569 }
1570 }
1571
1572 return 0;
1573
1574 err_out:
1575 swsusp_free();
1576 return -ENOMEM;
1577}
1578
1579asmlinkage int swsusp_save(void)
1580{
1581 unsigned int nr_pages, nr_highmem;
1582
1583 printk(KERN_INFO "PM: Creating hibernation image:\n");
1584
1585 drain_local_pages(NULL);
1586 nr_pages = count_data_pages();
1587 nr_highmem = count_highmem_pages();
1588 printk(KERN_INFO "PM: Need to copy %u pages\n", nr_pages + nr_highmem);
1589
1590 if (!enough_free_mem(nr_pages, nr_highmem)) {
1591 printk(KERN_ERR "PM: Not enough free memory\n");
1592 return -ENOMEM;
1593 }
1594
1595 if (swsusp_alloc(&orig_bm, ©_bm, nr_pages, nr_highmem)) {
1596 printk(KERN_ERR "PM: Memory allocation failed\n");
1597 return -ENOMEM;
1598 }
1599
1600 /* During allocating of suspend pagedir, new cold pages may appear.
1601 * Kill them.
1602 */
1603 drain_local_pages(NULL);
1604 copy_data_pages(©_bm, &orig_bm);
1605
1606 /*
1607 * End of critical section. From now on, we can write to memory,
1608 * but we should not touch disk. This specially means we must _not_
1609 * touch swap space! Except we must write out our image of course.
1610 */
1611
1612 nr_pages += nr_highmem;
1613 nr_copy_pages = nr_pages;
1614 nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
1615
1616 printk(KERN_INFO "PM: Hibernation image created (%d pages copied)\n",
1617 nr_pages);
1618
1619 return 0;
1620}
1621
1622#ifndef CONFIG_ARCH_HIBERNATION_HEADER
1623static int init_header_complete(struct swsusp_info *info)
1624{
1625 memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
1626 info->version_code = LINUX_VERSION_CODE;
1627 return 0;
1628}
1629
1630static char *check_image_kernel(struct swsusp_info *info)
1631{
1632 if (info->version_code != LINUX_VERSION_CODE)
1633 return "kernel version";
1634 if (strcmp(info->uts.sysname,init_utsname()->sysname))
1635 return "system type";
1636 if (strcmp(info->uts.release,init_utsname()->release))
1637 return "kernel release";
1638 if (strcmp(info->uts.version,init_utsname()->version))
1639 return "version";
1640 if (strcmp(info->uts.machine,init_utsname()->machine))
1641 return "machine";
1642 return NULL;
1643}
1644#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
1645
1646unsigned long snapshot_get_image_size(void)
1647{
1648 return nr_copy_pages + nr_meta_pages + 1;
1649}
1650
1651static int init_header(struct swsusp_info *info)
1652{
1653 memset(info, 0, sizeof(struct swsusp_info));
1654 info->num_physpages = num_physpages;
1655 info->image_pages = nr_copy_pages;
1656 info->pages = snapshot_get_image_size();
1657 info->size = info->pages;
1658 info->size <<= PAGE_SHIFT;
1659 return init_header_complete(info);
1660}
1661
1662/**
1663 * pack_pfns - pfns corresponding to the set bits found in the bitmap @bm
1664 * are stored in the array @buf[] (1 page at a time)
1665 */
1666
1667static inline void
1668pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
1669{
1670 int j;
1671
1672 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1673 buf[j] = memory_bm_next_pfn(bm);
1674 if (unlikely(buf[j] == BM_END_OF_MAP))
1675 break;
1676 /* Save page key for data page (s390 only). */
1677 page_key_read(buf + j);
1678 }
1679}
1680
1681/**
1682 * snapshot_read_next - used for reading the system memory snapshot.
1683 *
1684 * On the first call to it @handle should point to a zeroed
1685 * snapshot_handle structure. The structure gets updated and a pointer
1686 * to it should be passed to this function every next time.
1687 *
1688 * On success the function returns a positive number. Then, the caller
1689 * is allowed to read up to the returned number of bytes from the memory
1690 * location computed by the data_of() macro.
1691 *
1692 * The function returns 0 to indicate the end of data stream condition,
1693 * and a negative number is returned on error. In such cases the
1694 * structure pointed to by @handle is not updated and should not be used
1695 * any more.
1696 */
1697
1698int snapshot_read_next(struct snapshot_handle *handle)
1699{
1700 if (handle->cur > nr_meta_pages + nr_copy_pages)
1701 return 0;
1702
1703 if (!buffer) {
1704 /* This makes the buffer be freed by swsusp_free() */
1705 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
1706 if (!buffer)
1707 return -ENOMEM;
1708 }
1709 if (!handle->cur) {
1710 int error;
1711
1712 error = init_header((struct swsusp_info *)buffer);
1713 if (error)
1714 return error;
1715 handle->buffer = buffer;
1716 memory_bm_position_reset(&orig_bm);
1717 memory_bm_position_reset(©_bm);
1718 } else if (handle->cur <= nr_meta_pages) {
1719 clear_page(buffer);
1720 pack_pfns(buffer, &orig_bm);
1721 } else {
1722 struct page *page;
1723
1724 page = pfn_to_page(memory_bm_next_pfn(©_bm));
1725 if (PageHighMem(page)) {
1726 /* Highmem pages are copied to the buffer,
1727 * because we can't return with a kmapped
1728 * highmem page (we may not be called again).
1729 */
1730 void *kaddr;
1731
1732 kaddr = kmap_atomic(page);
1733 copy_page(buffer, kaddr);
1734 kunmap_atomic(kaddr);
1735 handle->buffer = buffer;
1736 } else {
1737 handle->buffer = page_address(page);
1738 }
1739 }
1740 handle->cur++;
1741 return PAGE_SIZE;
1742}
1743
1744/**
1745 * mark_unsafe_pages - mark the pages that cannot be used for storing
1746 * the image during resume, because they conflict with the pages that
1747 * had been used before suspend
1748 */
1749
1750static int mark_unsafe_pages(struct memory_bitmap *bm)
1751{
1752 struct zone *zone;
1753 unsigned long pfn, max_zone_pfn;
1754
1755 /* Clear page flags */
1756 for_each_populated_zone(zone) {
1757 max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
1758 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1759 if (pfn_valid(pfn))
1760 swsusp_unset_page_free(pfn_to_page(pfn));
1761 }
1762
1763 /* Mark pages that correspond to the "original" pfns as "unsafe" */
1764 memory_bm_position_reset(bm);
1765 do {
1766 pfn = memory_bm_next_pfn(bm);
1767 if (likely(pfn != BM_END_OF_MAP)) {
1768 if (likely(pfn_valid(pfn)))
1769 swsusp_set_page_free(pfn_to_page(pfn));
1770 else
1771 return -EFAULT;
1772 }
1773 } while (pfn != BM_END_OF_MAP);
1774
1775 allocated_unsafe_pages = 0;
1776
1777 return 0;
1778}
1779
1780static void
1781duplicate_memory_bitmap(struct memory_bitmap *dst, struct memory_bitmap *src)
1782{
1783 unsigned long pfn;
1784
1785 memory_bm_position_reset(src);
1786 pfn = memory_bm_next_pfn(src);
1787 while (pfn != BM_END_OF_MAP) {
1788 memory_bm_set_bit(dst, pfn);
1789 pfn = memory_bm_next_pfn(src);
1790 }
1791}
1792
1793static int check_header(struct swsusp_info *info)
1794{
1795 char *reason;
1796
1797 reason = check_image_kernel(info);
1798 if (!reason && info->num_physpages != num_physpages)
1799 reason = "memory size";
1800 if (reason) {
1801 printk(KERN_ERR "PM: Image mismatch: %s\n", reason);
1802 return -EPERM;
1803 }
1804 return 0;
1805}
1806
1807/**
1808 * load header - check the image header and copy data from it
1809 */
1810
1811static int
1812load_header(struct swsusp_info *info)
1813{
1814 int error;
1815
1816 restore_pblist = NULL;
1817 error = check_header(info);
1818 if (!error) {
1819 nr_copy_pages = info->image_pages;
1820 nr_meta_pages = info->pages - info->image_pages - 1;
1821 }
1822 return error;
1823}
1824
1825/**
1826 * unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
1827 * the corresponding bit in the memory bitmap @bm
1828 */
1829static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
1830{
1831 int j;
1832
1833 for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
1834 if (unlikely(buf[j] == BM_END_OF_MAP))
1835 break;
1836
1837 /* Extract and buffer page key for data page (s390 only). */
1838 page_key_memorize(buf + j);
1839
1840 if (memory_bm_pfn_present(bm, buf[j]))
1841 memory_bm_set_bit(bm, buf[j]);
1842 else
1843 return -EFAULT;
1844 }
1845
1846 return 0;
1847}
1848
1849/* List of "safe" pages that may be used to store data loaded from the suspend
1850 * image
1851 */
1852static struct linked_page *safe_pages_list;
1853
1854#ifdef CONFIG_HIGHMEM
1855/* struct highmem_pbe is used for creating the list of highmem pages that
1856 * should be restored atomically during the resume from disk, because the page
1857 * frames they have occupied before the suspend are in use.
1858 */
1859struct highmem_pbe {
1860 struct page *copy_page; /* data is here now */
1861 struct page *orig_page; /* data was here before the suspend */
1862 struct highmem_pbe *next;
1863};
1864
1865/* List of highmem PBEs needed for restoring the highmem pages that were
1866 * allocated before the suspend and included in the suspend image, but have
1867 * also been allocated by the "resume" kernel, so their contents cannot be
1868 * written directly to their "original" page frames.
1869 */
1870static struct highmem_pbe *highmem_pblist;
1871
1872/**
1873 * count_highmem_image_pages - compute the number of highmem pages in the
1874 * suspend image. The bits in the memory bitmap @bm that correspond to the
1875 * image pages are assumed to be set.
1876 */
1877
1878static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
1879{
1880 unsigned long pfn;
1881 unsigned int cnt = 0;
1882
1883 memory_bm_position_reset(bm);
1884 pfn = memory_bm_next_pfn(bm);
1885 while (pfn != BM_END_OF_MAP) {
1886 if (PageHighMem(pfn_to_page(pfn)))
1887 cnt++;
1888
1889 pfn = memory_bm_next_pfn(bm);
1890 }
1891 return cnt;
1892}
1893
1894/**
1895 * prepare_highmem_image - try to allocate as many highmem pages as
1896 * there are highmem image pages (@nr_highmem_p points to the variable
1897 * containing the number of highmem image pages). The pages that are
1898 * "safe" (ie. will not be overwritten when the suspend image is
1899 * restored) have the corresponding bits set in @bm (it must be
1900 * unitialized).
1901 *
1902 * NOTE: This function should not be called if there are no highmem
1903 * image pages.
1904 */
1905
1906static unsigned int safe_highmem_pages;
1907
1908static struct memory_bitmap *safe_highmem_bm;
1909
1910static int
1911prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
1912{
1913 unsigned int to_alloc;
1914
1915 if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
1916 return -ENOMEM;
1917
1918 if (get_highmem_buffer(PG_SAFE))
1919 return -ENOMEM;
1920
1921 to_alloc = count_free_highmem_pages();
1922 if (to_alloc > *nr_highmem_p)
1923 to_alloc = *nr_highmem_p;
1924 else
1925 *nr_highmem_p = to_alloc;
1926
1927 safe_highmem_pages = 0;
1928 while (to_alloc-- > 0) {
1929 struct page *page;
1930
1931 page = alloc_page(__GFP_HIGHMEM);
1932 if (!swsusp_page_is_free(page)) {
1933 /* The page is "safe", set its bit the bitmap */
1934 memory_bm_set_bit(bm, page_to_pfn(page));
1935 safe_highmem_pages++;
1936 }
1937 /* Mark the page as allocated */
1938 swsusp_set_page_forbidden(page);
1939 swsusp_set_page_free(page);
1940 }
1941 memory_bm_position_reset(bm);
1942 safe_highmem_bm = bm;
1943 return 0;
1944}
1945
1946/**
1947 * get_highmem_page_buffer - for given highmem image page find the buffer
1948 * that suspend_write_next() should set for its caller to write to.
1949 *
1950 * If the page is to be saved to its "original" page frame or a copy of
1951 * the page is to be made in the highmem, @buffer is returned. Otherwise,
1952 * the copy of the page is to be made in normal memory, so the address of
1953 * the copy is returned.
1954 *
1955 * If @buffer is returned, the caller of suspend_write_next() will write
1956 * the page's contents to @buffer, so they will have to be copied to the
1957 * right location on the next call to suspend_write_next() and it is done
1958 * with the help of copy_last_highmem_page(). For this purpose, if
1959 * @buffer is returned, @last_highmem page is set to the page to which
1960 * the data will have to be copied from @buffer.
1961 */
1962
1963static struct page *last_highmem_page;
1964
1965static void *
1966get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
1967{
1968 struct highmem_pbe *pbe;
1969 void *kaddr;
1970
1971 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
1972 /* We have allocated the "original" page frame and we can
1973 * use it directly to store the loaded page.
1974 */
1975 last_highmem_page = page;
1976 return buffer;
1977 }
1978 /* The "original" page frame has not been allocated and we have to
1979 * use a "safe" page frame to store the loaded page.
1980 */
1981 pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
1982 if (!pbe) {
1983 swsusp_free();
1984 return ERR_PTR(-ENOMEM);
1985 }
1986 pbe->orig_page = page;
1987 if (safe_highmem_pages > 0) {
1988 struct page *tmp;
1989
1990 /* Copy of the page will be stored in high memory */
1991 kaddr = buffer;
1992 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
1993 safe_highmem_pages--;
1994 last_highmem_page = tmp;
1995 pbe->copy_page = tmp;
1996 } else {
1997 /* Copy of the page will be stored in normal memory */
1998 kaddr = safe_pages_list;
1999 safe_pages_list = safe_pages_list->next;
2000 pbe->copy_page = virt_to_page(kaddr);
2001 }
2002 pbe->next = highmem_pblist;
2003 highmem_pblist = pbe;
2004 return kaddr;
2005}
2006
2007/**
2008 * copy_last_highmem_page - copy the contents of a highmem image from
2009 * @buffer, where the caller of snapshot_write_next() has place them,
2010 * to the right location represented by @last_highmem_page .
2011 */
2012
2013static void copy_last_highmem_page(void)
2014{
2015 if (last_highmem_page) {
2016 void *dst;
2017
2018 dst = kmap_atomic(last_highmem_page);
2019 copy_page(dst, buffer);
2020 kunmap_atomic(dst);
2021 last_highmem_page = NULL;
2022 }
2023}
2024
2025static inline int last_highmem_page_copied(void)
2026{
2027 return !last_highmem_page;
2028}
2029
2030static inline void free_highmem_data(void)
2031{
2032 if (safe_highmem_bm)
2033 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
2034
2035 if (buffer)
2036 free_image_page(buffer, PG_UNSAFE_CLEAR);
2037}
2038#else
2039static inline int get_safe_write_buffer(void) { return 0; }
2040
2041static unsigned int
2042count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
2043
2044static inline int
2045prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
2046{
2047 return 0;
2048}
2049
2050static inline void *
2051get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
2052{
2053 return ERR_PTR(-EINVAL);
2054}
2055
2056static inline void copy_last_highmem_page(void) {}
2057static inline int last_highmem_page_copied(void) { return 1; }
2058static inline void free_highmem_data(void) {}
2059#endif /* CONFIG_HIGHMEM */
2060
2061/**
2062 * prepare_image - use the memory bitmap @bm to mark the pages that will
2063 * be overwritten in the process of restoring the system memory state
2064 * from the suspend image ("unsafe" pages) and allocate memory for the
2065 * image.
2066 *
2067 * The idea is to allocate a new memory bitmap first and then allocate
2068 * as many pages as needed for the image data, but not to assign these
2069 * pages to specific tasks initially. Instead, we just mark them as
2070 * allocated and create a lists of "safe" pages that will be used
2071 * later. On systems with high memory a list of "safe" highmem pages is
2072 * also created.
2073 */
2074
2075#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
2076
2077static int
2078prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
2079{
2080 unsigned int nr_pages, nr_highmem;
2081 struct linked_page *sp_list, *lp;
2082 int error;
2083
2084 /* If there is no highmem, the buffer will not be necessary */
2085 free_image_page(buffer, PG_UNSAFE_CLEAR);
2086 buffer = NULL;
2087
2088 nr_highmem = count_highmem_image_pages(bm);
2089 error = mark_unsafe_pages(bm);
2090 if (error)
2091 goto Free;
2092
2093 error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
2094 if (error)
2095 goto Free;
2096
2097 duplicate_memory_bitmap(new_bm, bm);
2098 memory_bm_free(bm, PG_UNSAFE_KEEP);
2099 if (nr_highmem > 0) {
2100 error = prepare_highmem_image(bm, &nr_highmem);
2101 if (error)
2102 goto Free;
2103 }
2104 /* Reserve some safe pages for potential later use.
2105 *
2106 * NOTE: This way we make sure there will be enough safe pages for the
2107 * chain_alloc() in get_buffer(). It is a bit wasteful, but
2108 * nr_copy_pages cannot be greater than 50% of the memory anyway.
2109 */
2110 sp_list = NULL;
2111 /* nr_copy_pages cannot be lesser than allocated_unsafe_pages */
2112 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2113 nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
2114 while (nr_pages > 0) {
2115 lp = get_image_page(GFP_ATOMIC, PG_SAFE);
2116 if (!lp) {
2117 error = -ENOMEM;
2118 goto Free;
2119 }
2120 lp->next = sp_list;
2121 sp_list = lp;
2122 nr_pages--;
2123 }
2124 /* Preallocate memory for the image */
2125 safe_pages_list = NULL;
2126 nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2127 while (nr_pages > 0) {
2128 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
2129 if (!lp) {
2130 error = -ENOMEM;
2131 goto Free;
2132 }
2133 if (!swsusp_page_is_free(virt_to_page(lp))) {
2134 /* The page is "safe", add it to the list */
2135 lp->next = safe_pages_list;
2136 safe_pages_list = lp;
2137 }
2138 /* Mark the page as allocated */
2139 swsusp_set_page_forbidden(virt_to_page(lp));
2140 swsusp_set_page_free(virt_to_page(lp));
2141 nr_pages--;
2142 }
2143 /* Free the reserved safe pages so that chain_alloc() can use them */
2144 while (sp_list) {
2145 lp = sp_list->next;
2146 free_image_page(sp_list, PG_UNSAFE_CLEAR);
2147 sp_list = lp;
2148 }
2149 return 0;
2150
2151 Free:
2152 swsusp_free();
2153 return error;
2154}
2155
2156/**
2157 * get_buffer - compute the address that snapshot_write_next() should
2158 * set for its caller to write to.
2159 */
2160
2161static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
2162{
2163 struct pbe *pbe;
2164 struct page *page;
2165 unsigned long pfn = memory_bm_next_pfn(bm);
2166
2167 if (pfn == BM_END_OF_MAP)
2168 return ERR_PTR(-EFAULT);
2169
2170 page = pfn_to_page(pfn);
2171 if (PageHighMem(page))
2172 return get_highmem_page_buffer(page, ca);
2173
2174 if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2175 /* We have allocated the "original" page frame and we can
2176 * use it directly to store the loaded page.
2177 */
2178 return page_address(page);
2179
2180 /* The "original" page frame has not been allocated and we have to
2181 * use a "safe" page frame to store the loaded page.
2182 */
2183 pbe = chain_alloc(ca, sizeof(struct pbe));
2184 if (!pbe) {
2185 swsusp_free();
2186 return ERR_PTR(-ENOMEM);
2187 }
2188 pbe->orig_address = page_address(page);
2189 pbe->address = safe_pages_list;
2190 safe_pages_list = safe_pages_list->next;
2191 pbe->next = restore_pblist;
2192 restore_pblist = pbe;
2193 return pbe->address;
2194}
2195
2196/**
2197 * snapshot_write_next - used for writing the system memory snapshot.
2198 *
2199 * On the first call to it @handle should point to a zeroed
2200 * snapshot_handle structure. The structure gets updated and a pointer
2201 * to it should be passed to this function every next time.
2202 *
2203 * On success the function returns a positive number. Then, the caller
2204 * is allowed to write up to the returned number of bytes to the memory
2205 * location computed by the data_of() macro.
2206 *
2207 * The function returns 0 to indicate the "end of file" condition,
2208 * and a negative number is returned on error. In such cases the
2209 * structure pointed to by @handle is not updated and should not be used
2210 * any more.
2211 */
2212
2213int snapshot_write_next(struct snapshot_handle *handle)
2214{
2215 static struct chain_allocator ca;
2216 int error = 0;
2217
2218 /* Check if we have already loaded the entire image */
2219 if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
2220 return 0;
2221
2222 handle->sync_read = 1;
2223
2224 if (!handle->cur) {
2225 if (!buffer)
2226 /* This makes the buffer be freed by swsusp_free() */
2227 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2228
2229 if (!buffer)
2230 return -ENOMEM;
2231
2232 handle->buffer = buffer;
2233 } else if (handle->cur == 1) {
2234 error = load_header(buffer);
2235 if (error)
2236 return error;
2237
2238 error = memory_bm_create(©_bm, GFP_ATOMIC, PG_ANY);
2239 if (error)
2240 return error;
2241
2242 /* Allocate buffer for page keys. */
2243 error = page_key_alloc(nr_copy_pages);
2244 if (error)
2245 return error;
2246
2247 } else if (handle->cur <= nr_meta_pages + 1) {
2248 error = unpack_orig_pfns(buffer, ©_bm);
2249 if (error)
2250 return error;
2251
2252 if (handle->cur == nr_meta_pages + 1) {
2253 error = prepare_image(&orig_bm, ©_bm);
2254 if (error)
2255 return error;
2256
2257 chain_init(&ca, GFP_ATOMIC, PG_SAFE);
2258 memory_bm_position_reset(&orig_bm);
2259 restore_pblist = NULL;
2260 handle->buffer = get_buffer(&orig_bm, &ca);
2261 handle->sync_read = 0;
2262 if (IS_ERR(handle->buffer))
2263 return PTR_ERR(handle->buffer);
2264 }
2265 } else {
2266 copy_last_highmem_page();
2267 /* Restore page key for data page (s390 only). */
2268 page_key_write(handle->buffer);
2269 handle->buffer = get_buffer(&orig_bm, &ca);
2270 if (IS_ERR(handle->buffer))
2271 return PTR_ERR(handle->buffer);
2272 if (handle->buffer != buffer)
2273 handle->sync_read = 0;
2274 }
2275 handle->cur++;
2276 return PAGE_SIZE;
2277}
2278
2279/**
2280 * snapshot_write_finalize - must be called after the last call to
2281 * snapshot_write_next() in case the last page in the image happens
2282 * to be a highmem page and its contents should be stored in the
2283 * highmem. Additionally, it releases the memory that will not be
2284 * used any more.
2285 */
2286
2287void snapshot_write_finalize(struct snapshot_handle *handle)
2288{
2289 copy_last_highmem_page();
2290 /* Restore page key for data page (s390 only). */
2291 page_key_write(handle->buffer);
2292 page_key_free();
2293 /* Free only if we have loaded the image entirely */
2294 if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
2295 memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);
2296 free_highmem_data();
2297 }
2298}
2299
2300int snapshot_image_loaded(struct snapshot_handle *handle)
2301{
2302 return !(!nr_copy_pages || !last_highmem_page_copied() ||
2303 handle->cur <= nr_meta_pages + nr_copy_pages);
2304}
2305
2306#ifdef CONFIG_HIGHMEM
2307/* Assumes that @buf is ready and points to a "safe" page */
2308static inline void
2309swap_two_pages_data(struct page *p1, struct page *p2, void *buf)
2310{
2311 void *kaddr1, *kaddr2;
2312
2313 kaddr1 = kmap_atomic(p1);
2314 kaddr2 = kmap_atomic(p2);
2315 copy_page(buf, kaddr1);
2316 copy_page(kaddr1, kaddr2);
2317 copy_page(kaddr2, buf);
2318 kunmap_atomic(kaddr2);
2319 kunmap_atomic(kaddr1);
2320}
2321
2322/**
2323 * restore_highmem - for each highmem page that was allocated before
2324 * the suspend and included in the suspend image, and also has been
2325 * allocated by the "resume" kernel swap its current (ie. "before
2326 * resume") contents with the previous (ie. "before suspend") one.
2327 *
2328 * If the resume eventually fails, we can call this function once
2329 * again and restore the "before resume" highmem state.
2330 */
2331
2332int restore_highmem(void)
2333{
2334 struct highmem_pbe *pbe = highmem_pblist;
2335 void *buf;
2336
2337 if (!pbe)
2338 return 0;
2339
2340 buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2341 if (!buf)
2342 return -ENOMEM;
2343
2344 while (pbe) {
2345 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2346 pbe = pbe->next;
2347 }
2348 free_image_page(buf, PG_UNSAFE_CLEAR);
2349 return 0;
2350}
2351#endif /* CONFIG_HIGHMEM */