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