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