1	// SPDX-License-Identifier: GPL-2.0-only
2	/*
3	* linux/kernel/power/snapshot.c
4	*
5	* This file provides system snapshot/restore functionality for swsusp.
6	*
7	* Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
8	* Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
9	*/
10
11	#define pr_fmt(fmt) "PM: hibernation: " fmt
12
13	#include <linux/version.h>
14	#include <linux/module.h>
15	#include <linux/mm.h>
16	#include <linux/suspend.h>
17	#include <linux/delay.h>
18	#include <linux/bitops.h>
19	#include <linux/spinlock.h>
20	#include <linux/kernel.h>
21	#include <linux/pm.h>
22	#include <linux/device.h>
23	#include <linux/init.h>
24	#include <linux/memblock.h>
25	#include <linux/nmi.h>
26	#include <linux/syscalls.h>
27	#include <linux/console.h>
28	#include <linux/highmem.h>
29	#include <linux/list.h>
30	#include <linux/slab.h>
31	#include <linux/compiler.h>
32	#include <linux/ktime.h>
33	#include <linux/set_memory.h>
34
35	#include <linux/uaccess.h>
36	#include <asm/mmu_context.h>
37	#include <asm/tlbflush.h>
38	#include <asm/io.h>
39
40	#include "power.h"
41
42	#if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_ARCH_HAS_SET_MEMORY)
43	static bool hibernate_restore_protection;
44	static bool hibernate_restore_protection_active;
45
46	void enable_restore_image_protection(void)
47	{
48	hibernate_restore_protection = true;
49	}
50
51	static inline void hibernate_restore_protection_begin(void)
52	{
53	hibernate_restore_protection_active = hibernate_restore_protection;
54	}
55
56	static inline void hibernate_restore_protection_end(void)
57	{
58	hibernate_restore_protection_active = false;
59	}
60
61	static inline int __must_check hibernate_restore_protect_page(void *page_address)
62	{
63	if (hibernate_restore_protection_active)
64	return set_memory_ro(addr: (unsigned long)page_address, numpages: 1);
65	return 0;
66	}
67
68	static inline int hibernate_restore_unprotect_page(void *page_address)
69	{
70	if (hibernate_restore_protection_active)
71	return set_memory_rw(addr: (unsigned long)page_address, numpages: 1);
72	return 0;
73	}
74	#else
75	static inline void hibernate_restore_protection_begin(void) {}
76	static inline void hibernate_restore_protection_end(void) {}
77	static inline int __must_check hibernate_restore_protect_page(void *page_address) {return 0; }
78	static inline int hibernate_restore_unprotect_page(void *page_address) {return 0; }
79	#endif /* CONFIG_STRICT_KERNEL_RWX && CONFIG_ARCH_HAS_SET_MEMORY */
80
81
82	/*
83	* The calls to set_direct_map_*() should not fail because remapping a page
84	* here means that we only update protection bits in an existing PTE.
85	* It is still worth to have a warning here if something changes and this
86	* will no longer be the case.
87	*/
88	static inline void hibernate_map_page(struct page *page)
89	{
90	if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
91	int ret = set_direct_map_default_noflush(page);
92
93	if (ret)
94	pr_warn_once("Failed to remap page\n");
95	} else {
96	debug_pagealloc_map_pages(page, numpages: 1);
97	}
98	}
99
100	static inline void hibernate_unmap_page(struct page *page)
101	{
102	if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
103	unsigned long addr = (unsigned long)page_address(page);
104	int ret = set_direct_map_invalid_noflush(page);
105
106	if (ret)
107	pr_warn_once("Failed to remap page\n");
108
109	flush_tlb_kernel_range(start: addr, end: addr + PAGE_SIZE);
110	} else {
111	debug_pagealloc_unmap_pages(page, numpages: 1);
112	}
113	}
114
115	static int swsusp_page_is_free(struct page *);
116	static void swsusp_set_page_forbidden(struct page *);
117	static void swsusp_unset_page_forbidden(struct page *);
118
119	/*
120	* Number of bytes to reserve for memory allocations made by device drivers
121	* from their ->freeze() and ->freeze_noirq() callbacks so that they don't
122	* cause image creation to fail (tunable via /sys/power/reserved_size).
123	*/
124	unsigned long reserved_size;
125
126	void __init hibernate_reserved_size_init(void)
127	{
128	reserved_size = SPARE_PAGES * PAGE_SIZE;
129	}
130
131	/*
132	* Preferred image size in bytes (tunable via /sys/power/image_size).
133	* When it is set to N, swsusp will do its best to ensure the image
134	* size will not exceed N bytes, but if that is impossible, it will
135	* try to create the smallest image possible.
136	*/
137	unsigned long image_size;
138
139	void __init hibernate_image_size_init(void)
140	{
141	image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
142	}
143
144	/*
145	* List of PBEs needed for restoring the pages that were allocated before
146	* the suspend and included in the suspend image, but have also been
147	* allocated by the "resume" kernel, so their contents cannot be written
148	* directly to their "original" page frames.
149	*/
150	struct pbe *restore_pblist;
151
152	/* struct linked_page is used to build chains of pages */
153
154	#define LINKED_PAGE_DATA_SIZE (PAGE_SIZE - sizeof(void *))
155
156	struct linked_page {
157	struct linked_page *next;
158	char data[LINKED_PAGE_DATA_SIZE];
159	} __packed;
160
161	/*
162	* List of "safe" pages (ie. pages that were not used by the image kernel
163	* before hibernation) that may be used as temporary storage for image kernel
164	* memory contents.
165	*/
166	static struct linked_page *safe_pages_list;
167
168	/* Pointer to an auxiliary buffer (1 page) */
169	static void *buffer;
170
171	#define PG_ANY 0
172	#define PG_SAFE 1
173	#define PG_UNSAFE_CLEAR 1
174	#define PG_UNSAFE_KEEP 0
175
176	static unsigned int allocated_unsafe_pages;
177
178	/**
179	* get_image_page - Allocate a page for a hibernation image.
180	* @gfp_mask: GFP mask for the allocation.
181	* @safe_needed: Get pages that were not used before hibernation (restore only)
182	*
183	* During image restoration, for storing the PBE list and the image data, we can
184	* only use memory pages that do not conflict with the pages used before
185	* hibernation. The "unsafe" pages have PageNosaveFree set and we count them
186	* using allocated_unsafe_pages.
187	*
188	* Each allocated image page is marked as PageNosave and PageNosaveFree so that
189	* swsusp_free() can release it.
190	*/
191	static void *get_image_page(gfp_t gfp_mask, int safe_needed)
192	{
193	void *res;
194
195	res = (void *)get_zeroed_page(gfp_mask);
196	if (safe_needed)
197	while (res && swsusp_page_is_free(virt_to_page(res))) {
198	/* The page is unsafe, mark it for swsusp_free() */
199	swsusp_set_page_forbidden(virt_to_page(res));
200	allocated_unsafe_pages++;
201	res = (void *)get_zeroed_page(gfp_mask);
202	}
203	if (res) {
204	swsusp_set_page_forbidden(virt_to_page(res));
205	swsusp_set_page_free(virt_to_page(res));
206	}
207	return res;
208	}
209
210	static void *__get_safe_page(gfp_t gfp_mask)
211	{
212	if (safe_pages_list) {
213	void *ret = safe_pages_list;
214
215	safe_pages_list = safe_pages_list->next;
216	memset(ret, 0, PAGE_SIZE);
217	return ret;
218	}
219	return get_image_page(gfp_mask, PG_SAFE);
220	}
221
222	unsigned long get_safe_page(gfp_t gfp_mask)
223	{
224	return (unsigned long)__get_safe_page(gfp_mask);
225	}
226
227	static struct page *alloc_image_page(gfp_t gfp_mask)
228	{
229	struct page *page;
230
231	page = alloc_page(gfp_mask);
232	if (page) {
233	swsusp_set_page_forbidden(page);
234	swsusp_set_page_free(page);
235	}
236	return page;
237	}
238
239	static void recycle_safe_page(void *page_address)
240	{
241	struct linked_page *lp = page_address;
242
243	lp->next = safe_pages_list;
244	safe_pages_list = lp;
245	}
246
247	/**
248	* free_image_page - Free a page allocated for hibernation image.
249	* @addr: Address of the page to free.
250	* @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
251	*
252	* The page to free should have been allocated by get_image_page() (page flags
253	* set by it are affected).
254	*/
255	static inline void free_image_page(void *addr, int clear_nosave_free)
256	{
257	struct page *page;
258
259	BUG_ON(!virt_addr_valid(addr));
260
261	page = virt_to_page(addr);
262
263	swsusp_unset_page_forbidden(page);
264	if (clear_nosave_free)
265	swsusp_unset_page_free(page);
266
267	__free_page(page);
268	}
269
270	static inline void free_list_of_pages(struct linked_page *list,
271	int clear_page_nosave)
272	{
273	while (list) {
274	struct linked_page *lp = list->next;
275
276	free_image_page(addr: list, clear_nosave_free: clear_page_nosave);
277	list = lp;
278	}
279	}
280
281	/*
282	* struct chain_allocator is used for allocating small objects out of
283	* a linked list of pages called 'the chain'.
284	*
285	* The chain grows each time when there is no room for a new object in
286	* the current page. The allocated objects cannot be freed individually.
287	* It is only possible to free them all at once, by freeing the entire
288	* chain.
289	*
290	* NOTE: The chain allocator may be inefficient if the allocated objects
291	* are not much smaller than PAGE_SIZE.
292	*/
293	struct chain_allocator {
294	struct linked_page *chain; /* the chain */
295	unsigned int used_space; /* total size of objects allocated out
296	of the current page */
297	gfp_t gfp_mask; /* mask for allocating pages */
298	int safe_needed; /* if set, only "safe" pages are allocated */
299	};
300
301	static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask,
302	int safe_needed)
303	{
304	ca->chain = NULL;
305	ca->used_space = LINKED_PAGE_DATA_SIZE;
306	ca->gfp_mask = gfp_mask;
307	ca->safe_needed = safe_needed;
308	}
309
310	static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
311	{
312	void *ret;
313
314	if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
315	struct linked_page *lp;
316
317	lp = ca->safe_needed ? __get_safe_page(gfp_mask: ca->gfp_mask) :
318	get_image_page(gfp_mask: ca->gfp_mask, PG_ANY);
319	if (!lp)
320	return NULL;
321
322	lp->next = ca->chain;
323	ca->chain = lp;
324	ca->used_space = 0;
325	}
326	ret = ca->chain->data + ca->used_space;
327	ca->used_space += size;
328	return ret;
329	}
330
331	/*
332	* Data types related to memory bitmaps.
333	*
334	* Memory bitmap is a structure consisting of many linked lists of
335	* objects. The main list's elements are of type struct zone_bitmap
336	* and each of them corresponds to one zone. For each zone bitmap
337	* object there is a list of objects of type struct bm_block that
338	* represent each blocks of bitmap in which information is stored.
339	*
340	* struct memory_bitmap contains a pointer to the main list of zone
341	* bitmap objects, a struct bm_position used for browsing the bitmap,
342	* and a pointer to the list of pages used for allocating all of the
343	* zone bitmap objects and bitmap block objects.
344	*
345	* NOTE: It has to be possible to lay out the bitmap in memory
346	* using only allocations of order 0. Additionally, the bitmap is
347	* designed to work with arbitrary number of zones (this is over the
348	* top for now, but let's avoid making unnecessary assumptions ;-).
349	*
350	* struct zone_bitmap contains a pointer to a list of bitmap block
351	* objects and a pointer to the bitmap block object that has been
352	* most recently used for setting bits. Additionally, it contains the
353	* PFNs that correspond to the start and end of the represented zone.
354	*
355	* struct bm_block contains a pointer to the memory page in which
356	* information is stored (in the form of a block of bitmap)
357	* It also contains the pfns that correspond to the start and end of
358	* the represented memory area.
359	*
360	* The memory bitmap is organized as a radix tree to guarantee fast random
361	* access to the bits. There is one radix tree for each zone (as returned
362	* from create_mem_extents).
363	*
364	* One radix tree is represented by one struct mem_zone_bm_rtree. There are
365	* two linked lists for the nodes of the tree, one for the inner nodes and
366	* one for the leave nodes. The linked leave nodes are used for fast linear
367	* access of the memory bitmap.
368	*
369	* The struct rtree_node represents one node of the radix tree.
370	*/
371
372	#define BM_END_OF_MAP (~0UL)
373
374	#define BM_BITS_PER_BLOCK (PAGE_SIZE * BITS_PER_BYTE)
375	#define BM_BLOCK_SHIFT (PAGE_SHIFT + 3)
376	#define BM_BLOCK_MASK ((1UL << BM_BLOCK_SHIFT) - 1)
377
378	/*
379	* struct rtree_node is a wrapper struct to link the nodes
380	* of the rtree together for easy linear iteration over
381	* bits and easy freeing
382	*/
383	struct rtree_node {
384	struct list_head list;
385	unsigned long *data;
386	};
387
388	/*
389	* struct mem_zone_bm_rtree represents a bitmap used for one
390	* populated memory zone.
391	*/
392	struct mem_zone_bm_rtree {
393	struct list_head list; /* Link Zones together */
394	struct list_head nodes; /* Radix Tree inner nodes */
395	struct list_head leaves; /* Radix Tree leaves */
396	unsigned long start_pfn; /* Zone start page frame */
397	unsigned long end_pfn; /* Zone end page frame + 1 */
398	struct rtree_node *rtree; /* Radix Tree Root */
399	int levels; /* Number of Radix Tree Levels */
400	unsigned int blocks; /* Number of Bitmap Blocks */
401	};
402
403	/* struct bm_position is used for browsing memory bitmaps */
404
405	struct bm_position {
406	struct mem_zone_bm_rtree *zone;
407	struct rtree_node *node;
408	unsigned long node_pfn;
409	unsigned long cur_pfn;
410	int node_bit;
411	};
412
413	struct memory_bitmap {
414	struct list_head zones;
415	struct linked_page *p_list; /* list of pages used to store zone
416	bitmap objects and bitmap block
417	objects */
418	struct bm_position cur; /* most recently used bit position */
419	};
420
421	/* Functions that operate on memory bitmaps */
422
423	#define BM_ENTRIES_PER_LEVEL (PAGE_SIZE / sizeof(unsigned long))
424	#if BITS_PER_LONG == 32
425	#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 2)
426	#else
427	#define BM_RTREE_LEVEL_SHIFT (PAGE_SHIFT - 3)
428	#endif
429	#define BM_RTREE_LEVEL_MASK ((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
430
431	/**
432	* alloc_rtree_node - Allocate a new node and add it to the radix tree.
433	* @gfp_mask: GFP mask for the allocation.
434	* @safe_needed: Get pages not used before hibernation (restore only)
435	* @ca: Pointer to a linked list of pages ("a chain") to allocate from
436	* @list: Radix Tree node to add.
437	*
438	* This function is used to allocate inner nodes as well as the
439	* leave nodes of the radix tree. It also adds the node to the
440	* corresponding linked list passed in by the *list parameter.
441	*/
442	static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
443	struct chain_allocator *ca,
444	struct list_head *list)
445	{
446	struct rtree_node *node;
447
448	node = chain_alloc(ca, size: sizeof(struct rtree_node));
449	if (!node)
450	return NULL;
451
452	node->data = get_image_page(gfp_mask, safe_needed);
453	if (!node->data)
454	return NULL;
455
456	list_add_tail(new: &node->list, head: list);
457
458	return node;
459	}
460
461	/**
462	* add_rtree_block - Add a new leave node to the radix tree.
463	*
464	* The leave nodes need to be allocated in order to keep the leaves
465	* linked list in order. This is guaranteed by the zone->blocks
466	* counter.
467	*/
468	static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
469	int safe_needed, struct chain_allocator *ca)
470	{
471	struct rtree_node *node, *block, **dst;
472	unsigned int levels_needed, block_nr;
473	int i;
474
475	block_nr = zone->blocks;
476	levels_needed = 0;
477
478	/* How many levels do we need for this block nr? */
479	while (block_nr) {
480	levels_needed += 1;
481	block_nr >>= BM_RTREE_LEVEL_SHIFT;
482	}
483
484	/* Make sure the rtree has enough levels */
485	for (i = zone->levels; i < levels_needed; i++) {
486	node = alloc_rtree_node(gfp_mask, safe_needed, ca,
487	list: &zone->nodes);
488	if (!node)
489	return -ENOMEM;
490
491	node->data[0] = (unsigned long)zone->rtree;
492	zone->rtree = node;
493	zone->levels += 1;
494	}
495
496	/* Allocate new block */
497	block = alloc_rtree_node(gfp_mask, safe_needed, ca, list: &zone->leaves);
498	if (!block)
499	return -ENOMEM;
500
501	/* Now walk the rtree to insert the block */
502	node = zone->rtree;
503	dst = &zone->rtree;
504	block_nr = zone->blocks;
505	for (i = zone->levels; i > 0; i--) {
506	int index;
507
508	if (!node) {
509	node = alloc_rtree_node(gfp_mask, safe_needed, ca,
510	list: &zone->nodes);
511	if (!node)
512	return -ENOMEM;
513	*dst = node;
514	}
515
516	index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
517	index &= BM_RTREE_LEVEL_MASK;
518	dst = (struct rtree_node **)&((*dst)->data[index]);
519	node = *dst;
520	}
521
522	zone->blocks += 1;
523	*dst = block;
524
525	return 0;
526	}
527
528	static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
529	int clear_nosave_free);
530
531	/**
532	* create_zone_bm_rtree - Create a radix tree for one zone.
533	*
534	* Allocated the mem_zone_bm_rtree structure and initializes it.
535	* This function also allocated and builds the radix tree for the
536	* zone.
537	*/
538	static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
539	int safe_needed,
540	struct chain_allocator *ca,
541	unsigned long start,
542	unsigned long end)
543	{
544	struct mem_zone_bm_rtree *zone;
545	unsigned int i, nr_blocks;
546	unsigned long pages;
547
548	pages = end - start;
549	zone = chain_alloc(ca, size: sizeof(struct mem_zone_bm_rtree));
550	if (!zone)
551	return NULL;
552
553	INIT_LIST_HEAD(list: &zone->nodes);
554	INIT_LIST_HEAD(list: &zone->leaves);
555	zone->start_pfn = start;
556	zone->end_pfn = end;
557	nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
558
559	for (i = 0; i < nr_blocks; i++) {
560	if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
561	free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
562	return NULL;
563	}
564	}
565
566	return zone;
567	}
568
569	/**
570	* free_zone_bm_rtree - Free the memory of the radix tree.
571	*
572	* Free all node pages of the radix tree. The mem_zone_bm_rtree
573	* structure itself is not freed here nor are the rtree_node
574	* structs.
575	*/
576	static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
577	int clear_nosave_free)
578	{
579	struct rtree_node *node;
580
581	list_for_each_entry(node, &zone->nodes, list)
582	free_image_page(addr: node->data, clear_nosave_free);
583
584	list_for_each_entry(node, &zone->leaves, list)
585	free_image_page(addr: node->data, clear_nosave_free);
586	}
587
588	static void memory_bm_position_reset(struct memory_bitmap *bm)
589	{
590	bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
591	list);
592	bm->cur.node = list_entry(bm->cur.zone->leaves.next,
593	struct rtree_node, list);
594	bm->cur.node_pfn = 0;
595	bm->cur.cur_pfn = BM_END_OF_MAP;
596	bm->cur.node_bit = 0;
597	}
598
599	static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
600
601	struct mem_extent {
602	struct list_head hook;
603	unsigned long start;
604	unsigned long end;
605	};
606
607	/**
608	* free_mem_extents - Free a list of memory extents.
609	* @list: List of extents to free.
610	*/
611	static void free_mem_extents(struct list_head *list)
612	{
613	struct mem_extent *ext, *aux;
614
615	list_for_each_entry_safe(ext, aux, list, hook) {
616	list_del(entry: &ext->hook);
617	kfree(objp: ext);
618	}
619	}
620
621	/**
622	* create_mem_extents - Create a list of memory extents.
623	* @list: List to put the extents into.
624	* @gfp_mask: Mask to use for memory allocations.
625	*
626	* The extents represent contiguous ranges of PFNs.
627	*/
628	static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
629	{
630	struct zone *zone;
631
632	INIT_LIST_HEAD(list);
633
634	for_each_populated_zone(zone) {
635	unsigned long zone_start, zone_end;
636	struct mem_extent *ext, *cur, *aux;
637
638	zone_start = zone->zone_start_pfn;
639	zone_end = zone_end_pfn(zone);
640
641	list_for_each_entry(ext, list, hook)
642	if (zone_start <= ext->end)
643	break;
644
645	if (&ext->hook == list || zone_end < ext->start) {
646	/* New extent is necessary */
647	struct mem_extent *new_ext;
648
649	new_ext = kzalloc(size: sizeof(struct mem_extent), flags: gfp_mask);
650	if (!new_ext) {
651	free_mem_extents(list);
652	return -ENOMEM;
653	}
654	new_ext->start = zone_start;
655	new_ext->end = zone_end;
656	list_add_tail(new: &new_ext->hook, head: &ext->hook);
657	continue;
658	}
659
660	/* Merge this zone's range of PFNs with the existing one */
661	if (zone_start < ext->start)
662	ext->start = zone_start;
663	if (zone_end > ext->end)
664	ext->end = zone_end;
665
666	/* More merging may be possible */
667	cur = ext;
668	list_for_each_entry_safe_continue(cur, aux, list, hook) {
669	if (zone_end < cur->start)
670	break;
671	if (zone_end < cur->end)
672	ext->end = cur->end;
673	list_del(entry: &cur->hook);
674	kfree(objp: cur);
675	}
676	}
677
678	return 0;
679	}
680
681	/**
682	* memory_bm_create - Allocate memory for a memory bitmap.
683	*/
684	static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
685	int safe_needed)
686	{
687	struct chain_allocator ca;
688	struct list_head mem_extents;
689	struct mem_extent *ext;
690	int error;
691
692	chain_init(ca: &ca, gfp_mask, safe_needed);
693	INIT_LIST_HEAD(list: &bm->zones);
694
695	error = create_mem_extents(list: &mem_extents, gfp_mask);
696	if (error)
697	return error;
698
699	list_for_each_entry(ext, &mem_extents, hook) {
700	struct mem_zone_bm_rtree *zone;
701
702	zone = create_zone_bm_rtree(gfp_mask, safe_needed, ca: &ca,
703	start: ext->start, end: ext->end);
704	if (!zone) {
705	error = -ENOMEM;
706	goto Error;
707	}
708	list_add_tail(new: &zone->list, head: &bm->zones);
709	}
710
711	bm->p_list = ca.chain;
712	memory_bm_position_reset(bm);
713	Exit:
714	free_mem_extents(list: &mem_extents);
715	return error;
716
717	Error:
718	bm->p_list = ca.chain;
719	memory_bm_free(bm, PG_UNSAFE_CLEAR);
720	goto Exit;
721	}
722
723	/**
724	* memory_bm_free - Free memory occupied by the memory bitmap.
725	* @bm: Memory bitmap.
726	*/
727	static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
728	{
729	struct mem_zone_bm_rtree *zone;
730
731	list_for_each_entry(zone, &bm->zones, list)
732	free_zone_bm_rtree(zone, clear_nosave_free);
733
734	free_list_of_pages(list: bm->p_list, clear_page_nosave: clear_nosave_free);
735
736	INIT_LIST_HEAD(list: &bm->zones);
737	}
738
739	/**
740	* memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
741	*
742	* Find the bit in memory bitmap @bm that corresponds to the given PFN.
743	* The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
744	*
745	* Walk the radix tree to find the page containing the bit that represents @pfn
746	* and return the position of the bit in @addr and @bit_nr.
747	*/
748	static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
749	void **addr, unsigned int *bit_nr)
750	{
751	struct mem_zone_bm_rtree *curr, *zone;
752	struct rtree_node *node;
753	int i, block_nr;
754
755	zone = bm->cur.zone;
756
757	if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
758	goto zone_found;
759
760	zone = NULL;
761
762	/* Find the right zone */
763	list_for_each_entry(curr, &bm->zones, list) {
764	if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
765	zone = curr;
766	break;
767	}
768	}
769
770	if (!zone)
771	return -EFAULT;
772
773	zone_found:
774	/*
775	* We have found the zone. Now walk the radix tree to find the leaf node
776	* for our PFN.
777	*/
778
779	/*
780	* If the zone we wish to scan is the current zone and the
781	* pfn falls into the current node then we do not need to walk
782	* the tree.
783	*/
784	node = bm->cur.node;
785	if (zone == bm->cur.zone &&
786	((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
787	goto node_found;
788
789	node = zone->rtree;
790	block_nr = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
791
792	for (i = zone->levels; i > 0; i--) {
793	int index;
794
795	index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
796	index &= BM_RTREE_LEVEL_MASK;
797	BUG_ON(node->data[index] == 0);
798	node = (struct rtree_node *)node->data[index];
799	}
800
801	node_found:
802	/* Update last position */
803	bm->cur.zone = zone;
804	bm->cur.node = node;
805	bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
806	bm->cur.cur_pfn = pfn;
807
808	/* Set return values */
809	*addr = node->data;
810	*bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
811
812	return 0;
813	}
814
815	static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
816	{
817	void *addr;
818	unsigned int bit;
819	int error;
820
821	error = memory_bm_find_bit(bm, pfn, addr: &addr, bit_nr: &bit);
822	BUG_ON(error);
823	set_bit(nr: bit, addr);
824	}
825
826	static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
827	{
828	void *addr;
829	unsigned int bit;
830	int error;
831
832	error = memory_bm_find_bit(bm, pfn, addr: &addr, bit_nr: &bit);
833	if (!error)
834	set_bit(nr: bit, addr);
835
836	return error;
837	}
838
839	static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
840	{
841	void *addr;
842	unsigned int bit;
843	int error;
844
845	error = memory_bm_find_bit(bm, pfn, addr: &addr, bit_nr: &bit);
846	BUG_ON(error);
847	clear_bit(nr: bit, addr);
848	}
849
850	static void memory_bm_clear_current(struct memory_bitmap *bm)
851	{
852	int bit;
853
854	bit = max(bm->cur.node_bit - 1, 0);
855	clear_bit(nr: bit, addr: bm->cur.node->data);
856	}
857
858	static unsigned long memory_bm_get_current(struct memory_bitmap *bm)
859	{
860	return bm->cur.cur_pfn;
861	}
862
863	static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
864	{
865	void *addr;
866	unsigned int bit;
867	int error;
868
869	error = memory_bm_find_bit(bm, pfn, addr: &addr, bit_nr: &bit);
870	BUG_ON(error);
871	return test_bit(bit, addr);
872	}
873
874	static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
875	{
876	void *addr;
877	unsigned int bit;
878
879	return !memory_bm_find_bit(bm, pfn, addr: &addr, bit_nr: &bit);
880	}
881
882	/*
883	* rtree_next_node - Jump to the next leaf node.
884	*
885	* Set the position to the beginning of the next node in the
886	* memory bitmap. This is either the next node in the current
887	* zone's radix tree or the first node in the radix tree of the
888	* next zone.
889	*
890	* Return true if there is a next node, false otherwise.
891	*/
892	static bool rtree_next_node(struct memory_bitmap *bm)
893	{
894	if (!list_is_last(list: &bm->cur.node->list, head: &bm->cur.zone->leaves)) {
895	bm->cur.node = list_entry(bm->cur.node->list.next,
896	struct rtree_node, list);
897	bm->cur.node_pfn += BM_BITS_PER_BLOCK;
898	bm->cur.node_bit = 0;
899	touch_softlockup_watchdog();
900	return true;
901	}
902
903	/* No more nodes, goto next zone */
904	if (!list_is_last(list: &bm->cur.zone->list, head: &bm->zones)) {
905	bm->cur.zone = list_entry(bm->cur.zone->list.next,
906	struct mem_zone_bm_rtree, list);
907	bm->cur.node = list_entry(bm->cur.zone->leaves.next,
908	struct rtree_node, list);
909	bm->cur.node_pfn = 0;
910	bm->cur.node_bit = 0;
911	return true;
912	}
913
914	/* No more zones */
915	return false;
916	}
917
918	/**
919	* memory_bm_next_pfn - Find the next set bit in a memory bitmap.
920	* @bm: Memory bitmap.
921	*
922	* Starting from the last returned position this function searches for the next
923	* set bit in @bm and returns the PFN represented by it. If no more bits are
924	* set, BM_END_OF_MAP is returned.
925	*
926	* It is required to run memory_bm_position_reset() before the first call to
927	* this function for the given memory bitmap.
928	*/
929	static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
930	{
931	unsigned long bits, pfn, pages;
932	int bit;
933
934	do {
935	pages = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
936	bits = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
937	bit = find_next_bit(addr: bm->cur.node->data, size: bits,
938	offset: bm->cur.node_bit);
939	if (bit < bits) {
940	pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
941	bm->cur.node_bit = bit + 1;
942	bm->cur.cur_pfn = pfn;
943	return pfn;
944	}
945	} while (rtree_next_node(bm));
946
947	bm->cur.cur_pfn = BM_END_OF_MAP;
948	return BM_END_OF_MAP;
949	}
950
951	/*
952	* This structure represents a range of page frames the contents of which
953	* should not be saved during hibernation.
954	*/
955	struct nosave_region {
956	struct list_head list;
957	unsigned long start_pfn;
958	unsigned long end_pfn;
959	};
960
961	static LIST_HEAD(nosave_regions);
962
963	static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone)
964	{
965	struct rtree_node *node;
966
967	list_for_each_entry(node, &zone->nodes, list)
968	recycle_safe_page(page_address: node->data);
969
970	list_for_each_entry(node, &zone->leaves, list)
971	recycle_safe_page(page_address: node->data);
972	}
973
974	static void memory_bm_recycle(struct memory_bitmap *bm)
975	{
976	struct mem_zone_bm_rtree *zone;
977	struct linked_page *p_list;
978
979	list_for_each_entry(zone, &bm->zones, list)
980	recycle_zone_bm_rtree(zone);
981
982	p_list = bm->p_list;
983	while (p_list) {
984	struct linked_page *lp = p_list;
985
986	p_list = lp->next;
987	recycle_safe_page(page_address: lp);
988	}
989	}
990
991	/**
992	* register_nosave_region - Register a region of unsaveable memory.
993	*
994	* Register a range of page frames the contents of which should not be saved
995	* during hibernation (to be used in the early initialization code).
996	*/
997	void __init register_nosave_region(unsigned long start_pfn, unsigned long end_pfn)
998	{
999	struct nosave_region *region;
1000
1001	if (start_pfn >= end_pfn)
1002	return;
1003
1004	if (!list_empty(head: &nosave_regions)) {
1005	/* Try to extend the previous region (they should be sorted) */
1006	region = list_entry(nosave_regions.prev,
1007	struct nosave_region, list);
1008	if (region->end_pfn == start_pfn) {
1009	region->end_pfn = end_pfn;
1010	goto Report;
1011	}
1012	}
1013	/* This allocation cannot fail */
1014	region = memblock_alloc(size: sizeof(struct nosave_region),
1015	SMP_CACHE_BYTES);
1016	if (!region)
1017	panic(fmt: "%s: Failed to allocate %zu bytes\n", __func__,
1018	sizeof(struct nosave_region));
1019	region->start_pfn = start_pfn;
1020	region->end_pfn = end_pfn;
1021	list_add_tail(new: &region->list, head: &nosave_regions);
1022	Report:
1023	pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n",
1024	(unsigned long long) start_pfn << PAGE_SHIFT,
1025	((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1026	}
1027
1028	/*
1029	* Set bits in this map correspond to the page frames the contents of which
1030	* should not be saved during the suspend.
1031	*/
1032	static struct memory_bitmap *forbidden_pages_map;
1033
1034	/* Set bits in this map correspond to free page frames. */
1035	static struct memory_bitmap *free_pages_map;
1036
1037	/*
1038	* Each page frame allocated for creating the image is marked by setting the
1039	* corresponding bits in forbidden_pages_map and free_pages_map simultaneously
1040	*/
1041
1042	void swsusp_set_page_free(struct page *page)
1043	{
1044	if (free_pages_map)
1045	memory_bm_set_bit(bm: free_pages_map, page_to_pfn(page));
1046	}
1047
1048	static int swsusp_page_is_free(struct page *page)
1049	{
1050	return free_pages_map ?
1051	memory_bm_test_bit(bm: free_pages_map, page_to_pfn(page)) : 0;
1052	}
1053
1054	void swsusp_unset_page_free(struct page *page)
1055	{
1056	if (free_pages_map)
1057	memory_bm_clear_bit(bm: free_pages_map, page_to_pfn(page));
1058	}
1059
1060	static void swsusp_set_page_forbidden(struct page *page)
1061	{
1062	if (forbidden_pages_map)
1063	memory_bm_set_bit(bm: forbidden_pages_map, page_to_pfn(page));
1064	}
1065
1066	int swsusp_page_is_forbidden(struct page *page)
1067	{
1068	return forbidden_pages_map ?
1069	memory_bm_test_bit(bm: forbidden_pages_map, page_to_pfn(page)) : 0;
1070	}
1071
1072	static void swsusp_unset_page_forbidden(struct page *page)
1073	{
1074	if (forbidden_pages_map)
1075	memory_bm_clear_bit(bm: forbidden_pages_map, page_to_pfn(page));
1076	}
1077
1078	/**
1079	* mark_nosave_pages - Mark pages that should not be saved.
1080	* @bm: Memory bitmap.
1081	*
1082	* Set the bits in @bm that correspond to the page frames the contents of which
1083	* should not be saved.
1084	*/
1085	static void mark_nosave_pages(struct memory_bitmap *bm)
1086	{
1087	struct nosave_region *region;
1088
1089	if (list_empty(head: &nosave_regions))
1090	return;
1091
1092	list_for_each_entry(region, &nosave_regions, list) {
1093	unsigned long pfn;
1094
1095	pr_debug("Marking nosave pages: [mem %#010llx-%#010llx]\n",
1096	(unsigned long long) region->start_pfn << PAGE_SHIFT,
1097	((unsigned long long) region->end_pfn << PAGE_SHIFT)
1098	- 1);
1099
1100	for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
1101	if (pfn_valid(pfn)) {
1102	/*
1103	* It is safe to ignore the result of
1104	* mem_bm_set_bit_check() here, since we won't
1105	* touch the PFNs for which the error is
1106	* returned anyway.
1107	*/
1108	mem_bm_set_bit_check(bm, pfn);
1109	}
1110	}
1111	}
1112
1113	/**
1114	* create_basic_memory_bitmaps - Create bitmaps to hold basic page information.
1115	*
1116	* Create bitmaps needed for marking page frames that should not be saved and
1117	* free page frames. The forbidden_pages_map and free_pages_map pointers are
1118	* only modified if everything goes well, because we don't want the bits to be
1119	* touched before both bitmaps are set up.
1120	*/
1121	int create_basic_memory_bitmaps(void)
1122	{
1123	struct memory_bitmap *bm1, *bm2;
1124	int error;
1125
1126	if (forbidden_pages_map && free_pages_map)
1127	return 0;
1128	else
1129	BUG_ON(forbidden_pages_map || free_pages_map);
1130
1131	bm1 = kzalloc(size: sizeof(struct memory_bitmap), GFP_KERNEL);
1132	if (!bm1)
1133	return -ENOMEM;
1134
1135	error = memory_bm_create(bm: bm1, GFP_KERNEL, PG_ANY);
1136	if (error)
1137	goto Free_first_object;
1138
1139	bm2 = kzalloc(size: sizeof(struct memory_bitmap), GFP_KERNEL);
1140	if (!bm2)
1141	goto Free_first_bitmap;
1142
1143	error = memory_bm_create(bm: bm2, GFP_KERNEL, PG_ANY);
1144	if (error)
1145	goto Free_second_object;
1146
1147	forbidden_pages_map = bm1;
1148	free_pages_map = bm2;
1149	mark_nosave_pages(bm: forbidden_pages_map);
1150
1151	pr_debug("Basic memory bitmaps created\n");
1152
1153	return 0;
1154
1155	Free_second_object:
1156	kfree(objp: bm2);
1157	Free_first_bitmap:
1158	memory_bm_free(bm: bm1, PG_UNSAFE_CLEAR);
1159	Free_first_object:
1160	kfree(objp: bm1);
1161	return -ENOMEM;
1162	}
1163
1164	/**
1165	* free_basic_memory_bitmaps - Free memory bitmaps holding basic information.
1166	*
1167	* Free memory bitmaps allocated by create_basic_memory_bitmaps(). The
1168	* auxiliary pointers are necessary so that the bitmaps themselves are not
1169	* referred to while they are being freed.
1170	*/
1171	void free_basic_memory_bitmaps(void)
1172	{
1173	struct memory_bitmap *bm1, *bm2;
1174
1175	if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
1176	return;
1177
1178	bm1 = forbidden_pages_map;
1179	bm2 = free_pages_map;
1180	forbidden_pages_map = NULL;
1181	free_pages_map = NULL;
1182	memory_bm_free(bm: bm1, PG_UNSAFE_CLEAR);
1183	kfree(objp: bm1);
1184	memory_bm_free(bm: bm2, PG_UNSAFE_CLEAR);
1185	kfree(objp: bm2);
1186
1187	pr_debug("Basic memory bitmaps freed\n");
1188	}
1189
1190	static void clear_or_poison_free_page(struct page *page)
1191	{
1192	if (page_poisoning_enabled_static())
1193	__kernel_poison_pages(page, numpages: 1);
1194	else if (want_init_on_free())
1195	clear_highpage(page);
1196	}
1197
1198	void clear_or_poison_free_pages(void)
1199	{
1200	struct memory_bitmap *bm = free_pages_map;
1201	unsigned long pfn;
1202
1203	if (WARN_ON(!(free_pages_map)))
1204	return;
1205
1206	if (page_poisoning_enabled() || want_init_on_free()) {
1207	memory_bm_position_reset(bm);
1208	pfn = memory_bm_next_pfn(bm);
1209	while (pfn != BM_END_OF_MAP) {
1210	if (pfn_valid(pfn))
1211	clear_or_poison_free_page(pfn_to_page(pfn));
1212
1213	pfn = memory_bm_next_pfn(bm);
1214	}
1215	memory_bm_position_reset(bm);
1216	pr_info("free pages cleared after restore\n");
1217	}
1218	}
1219
1220	/**
1221	* snapshot_additional_pages - Estimate the number of extra pages needed.
1222	* @zone: Memory zone to carry out the computation for.
1223	*
1224	* Estimate the number of additional pages needed for setting up a hibernation
1225	* image data structures for @zone (usually, the returned value is greater than
1226	* the exact number).
1227	*/
1228	unsigned int snapshot_additional_pages(struct zone *zone)
1229	{
1230	unsigned int rtree, nodes;
1231
1232	rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
1233	rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
1234	LINKED_PAGE_DATA_SIZE);
1235	while (nodes > 1) {
1236	nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
1237	rtree += nodes;
1238	}
1239
1240	return 2 * rtree;
1241	}
1242
1243	/*
1244	* Touch the watchdog for every WD_PAGE_COUNT pages.
1245	*/
1246	#define WD_PAGE_COUNT (128*1024)
1247
1248	static void mark_free_pages(struct zone *zone)
1249	{
1250	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
1251	unsigned long flags;
1252	unsigned int order, t;
1253	struct page *page;
1254
1255	if (zone_is_empty(zone))
1256	return;
1257
1258	spin_lock_irqsave(&zone->lock, flags);
1259
1260	max_zone_pfn = zone_end_pfn(zone);
1261	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1262	if (pfn_valid(pfn)) {
1263	page = pfn_to_page(pfn);
1264
1265	if (!--page_count) {
1266	touch_nmi_watchdog();
1267	page_count = WD_PAGE_COUNT;
1268	}
1269
1270	if (page_zone(page) != zone)
1271	continue;
1272
1273	if (!swsusp_page_is_forbidden(page))
1274	swsusp_unset_page_free(page);
1275	}
1276
1277	for_each_migratetype_order(order, t) {
1278	list_for_each_entry(page,
1279	&zone->free_area[order].free_list[t], buddy_list) {
1280	unsigned long i;
1281
1282	pfn = page_to_pfn(page);
1283	for (i = 0; i < (1UL << order); i++) {
1284	if (!--page_count) {
1285	touch_nmi_watchdog();
1286	page_count = WD_PAGE_COUNT;
1287	}
1288	swsusp_set_page_free(pfn_to_page(pfn + i));
1289	}
1290	}
1291	}
1292	spin_unlock_irqrestore(lock: &zone->lock, flags);
1293	}
1294
1295	#ifdef CONFIG_HIGHMEM
1296	/**
1297	* count_free_highmem_pages - Compute the total number of free highmem pages.
1298	*
1299	* The returned number is system-wide.
1300	*/
1301	static unsigned int count_free_highmem_pages(void)
1302	{
1303	struct zone *zone;
1304	unsigned int cnt = 0;
1305
1306	for_each_populated_zone(zone)
1307	if (is_highmem(zone))
1308	cnt += zone_page_state(zone, NR_FREE_PAGES);
1309
1310	return cnt;
1311	}
1312
1313	/**
1314	* saveable_highmem_page - Check if a highmem page is saveable.
1315	*
1316	* Determine whether a highmem page should be included in a hibernation image.
1317	*
1318	* We should save the page if it isn't Nosave or NosaveFree, or Reserved,
1319	* and it isn't part of a free chunk of pages.
1320	*/
1321	static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
1322	{
1323	struct page *page;
1324
1325	if (!pfn_valid(pfn))
1326	return NULL;
1327
1328	page = pfn_to_online_page(pfn);
1329	if (!page || page_zone(page) != zone)
1330	return NULL;
1331
1332	BUG_ON(!PageHighMem(page));
1333
1334	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
1335	return NULL;
1336
1337	if (PageReserved(page) || PageOffline(page))
1338	return NULL;
1339
1340	if (page_is_guard(page))
1341	return NULL;
1342
1343	return page;
1344	}
1345
1346	/**
1347	* count_highmem_pages - Compute the total number of saveable highmem pages.
1348	*/
1349	static unsigned int count_highmem_pages(void)
1350	{
1351	struct zone *zone;
1352	unsigned int n = 0;
1353
1354	for_each_populated_zone(zone) {
1355	unsigned long pfn, max_zone_pfn;
1356
1357	if (!is_highmem(zone))
1358	continue;
1359
1360	mark_free_pages(zone);
1361	max_zone_pfn = zone_end_pfn(zone);
1362	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1363	if (saveable_highmem_page(zone, pfn))
1364	n++;
1365	}
1366	return n;
1367	}
1368	#else
1369	static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
1370	{
1371	return NULL;
1372	}
1373	#endif /* CONFIG_HIGHMEM */
1374
1375	/**
1376	* saveable_page - Check if the given page is saveable.
1377	*
1378	* Determine whether a non-highmem page should be included in a hibernation
1379	* image.
1380	*
1381	* We should save the page if it isn't Nosave, and is not in the range
1382	* of pages statically defined as 'unsaveable', and it isn't part of
1383	* a free chunk of pages.
1384	*/
1385	static struct page *saveable_page(struct zone *zone, unsigned long pfn)
1386	{
1387	struct page *page;
1388
1389	if (!pfn_valid(pfn))
1390	return NULL;
1391
1392	page = pfn_to_online_page(pfn);
1393	if (!page || page_zone(page) != zone)
1394	return NULL;
1395
1396	BUG_ON(PageHighMem(page));
1397
1398	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
1399	return NULL;
1400
1401	if (PageOffline(page))
1402	return NULL;
1403
1404	if (PageReserved(page)
1405	&& (!kernel_page_present(page) || pfn_is_nosave(pfn)))
1406	return NULL;
1407
1408	if (page_is_guard(page))
1409	return NULL;
1410
1411	return page;
1412	}
1413
1414	/**
1415	* count_data_pages - Compute the total number of saveable non-highmem pages.
1416	*/
1417	static unsigned int count_data_pages(void)
1418	{
1419	struct zone *zone;
1420	unsigned long pfn, max_zone_pfn;
1421	unsigned int n = 0;
1422
1423	for_each_populated_zone(zone) {
1424	if (is_highmem(zone))
1425	continue;
1426
1427	mark_free_pages(zone);
1428	max_zone_pfn = zone_end_pfn(zone);
1429	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1430	if (saveable_page(zone, pfn))
1431	n++;
1432	}
1433	return n;
1434	}
1435
1436	/*
1437	* This is needed, because copy_page and memcpy are not usable for copying
1438	* task structs. Returns true if the page was filled with only zeros,
1439	* otherwise false.
1440	*/
1441	static inline bool do_copy_page(long *dst, long *src)
1442	{
1443	long z = 0;
1444	int n;
1445
1446	for (n = PAGE_SIZE / sizeof(long); n; n--) {
1447	z |= *src;
1448	*dst++ = *src++;
1449	}
1450	return !z;
1451	}
1452
1453	/**
1454	* safe_copy_page - Copy a page in a safe way.
1455	*
1456	* Check if the page we are going to copy is marked as present in the kernel
1457	* page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
1458	* CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
1459	* always returns 'true'. Returns true if the page was entirely composed of
1460	* zeros, otherwise it will return false.
1461	*/
1462	static bool safe_copy_page(void *dst, struct page *s_page)
1463	{
1464	bool zeros_only;
1465
1466	if (kernel_page_present(page: s_page)) {
1467	zeros_only = do_copy_page(dst, page_address(s_page));
1468	} else {
1469	hibernate_map_page(page: s_page);
1470	zeros_only = do_copy_page(dst, page_address(s_page));
1471	hibernate_unmap_page(page: s_page);
1472	}
1473	return zeros_only;
1474	}
1475
1476	#ifdef CONFIG_HIGHMEM
1477	static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
1478	{
1479	return is_highmem(zone) ?
1480	saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
1481	}
1482
1483	static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1484	{
1485	struct page *s_page, *d_page;
1486	void *src, *dst;
1487	bool zeros_only;
1488
1489	s_page = pfn_to_page(src_pfn);
1490	d_page = pfn_to_page(dst_pfn);
1491	if (PageHighMem(s_page)) {
1492	src = kmap_local_page(s_page);
1493	dst = kmap_local_page(d_page);
1494	zeros_only = do_copy_page(dst, src);
1495	kunmap_local(dst);
1496	kunmap_local(src);
1497	} else {
1498	if (PageHighMem(d_page)) {
1499	/*
1500	* The page pointed to by src may contain some kernel
1501	* data modified by kmap_atomic()
1502	*/
1503	zeros_only = safe_copy_page(buffer, s_page);
1504	dst = kmap_local_page(d_page);
1505	copy_page(dst, buffer);
1506	kunmap_local(dst);
1507	} else {
1508	zeros_only = safe_copy_page(page_address(d_page), s_page);
1509	}
1510	}
1511	return zeros_only;
1512	}
1513	#else
1514	#define page_is_saveable(zone, pfn) saveable_page(zone, pfn)
1515
1516	static inline int copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1517	{
1518	return safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1519	pfn_to_page(src_pfn));
1520	}
1521	#endif /* CONFIG_HIGHMEM */
1522
1523	/*
1524	* Copy data pages will copy all pages into pages pulled from the copy_bm.
1525	* If a page was entirely filled with zeros it will be marked in the zero_bm.
1526	*
1527	* Returns the number of pages copied.
1528	*/
1529	static unsigned long copy_data_pages(struct memory_bitmap *copy_bm,
1530	struct memory_bitmap *orig_bm,
1531	struct memory_bitmap *zero_bm)
1532	{
1533	unsigned long copied_pages = 0;
1534	struct zone *zone;
1535	unsigned long pfn, copy_pfn;
1536
1537	for_each_populated_zone(zone) {
1538	unsigned long max_zone_pfn;
1539
1540	mark_free_pages(zone);
1541	max_zone_pfn = zone_end_pfn(zone);
1542	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1543	if (page_is_saveable(zone, pfn))
1544	memory_bm_set_bit(bm: orig_bm, pfn);
1545	}
1546	memory_bm_position_reset(bm: orig_bm);
1547	memory_bm_position_reset(bm: copy_bm);
1548	copy_pfn = memory_bm_next_pfn(bm: copy_bm);
1549	for(;;) {
1550	pfn = memory_bm_next_pfn(bm: orig_bm);
1551	if (unlikely(pfn == BM_END_OF_MAP))
1552	break;
1553	if (copy_data_page(dst_pfn: copy_pfn, src_pfn: pfn)) {
1554	memory_bm_set_bit(bm: zero_bm, pfn);
1555	/* Use this copy_pfn for a page that is not full of zeros */
1556	continue;
1557	}
1558	copied_pages++;
1559	copy_pfn = memory_bm_next_pfn(bm: copy_bm);
1560	}
1561	return copied_pages;
1562	}
1563
1564	/* Total number of image pages */
1565	static unsigned int nr_copy_pages;
1566	/* Number of pages needed for saving the original pfns of the image pages */
1567	static unsigned int nr_meta_pages;
1568	/* Number of zero pages */
1569	static unsigned int nr_zero_pages;
1570
1571	/*
1572	* Numbers of normal and highmem page frames allocated for hibernation image
1573	* before suspending devices.
1574	*/
1575	static unsigned int alloc_normal, alloc_highmem;
1576	/*
1577	* Memory bitmap used for marking saveable pages (during hibernation) or
1578	* hibernation image pages (during restore)
1579	*/
1580	static struct memory_bitmap orig_bm;
1581	/*
1582	* Memory bitmap used during hibernation for marking allocated page frames that
1583	* will contain copies of saveable pages. During restore it is initially used
1584	* for marking hibernation image pages, but then the set bits from it are
1585	* duplicated in @orig_bm and it is released. On highmem systems it is next
1586	* used for marking "safe" highmem pages, but it has to be reinitialized for
1587	* this purpose.
1588	*/
1589	static struct memory_bitmap copy_bm;
1590
1591	/* Memory bitmap which tracks which saveable pages were zero filled. */
1592	static struct memory_bitmap zero_bm;
1593
1594	/**
1595	* swsusp_free - Free pages allocated for hibernation image.
1596	*
1597	* Image pages are allocated before snapshot creation, so they need to be
1598	* released after resume.
1599	*/
1600	void swsusp_free(void)
1601	{
1602	unsigned long fb_pfn, fr_pfn;
1603
1604	if (!forbidden_pages_map || !free_pages_map)
1605	goto out;
1606
1607	memory_bm_position_reset(bm: forbidden_pages_map);
1608	memory_bm_position_reset(bm: free_pages_map);
1609
1610	loop:
1611	fr_pfn = memory_bm_next_pfn(bm: free_pages_map);
1612	fb_pfn = memory_bm_next_pfn(bm: forbidden_pages_map);
1613
1614	/*
1615	* Find the next bit set in both bitmaps. This is guaranteed to
1616	* terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
1617	*/
1618	do {
1619	if (fb_pfn < fr_pfn)
1620	fb_pfn = memory_bm_next_pfn(bm: forbidden_pages_map);
1621	if (fr_pfn < fb_pfn)
1622	fr_pfn = memory_bm_next_pfn(bm: free_pages_map);
1623	} while (fb_pfn != fr_pfn);
1624
1625	if (fr_pfn != BM_END_OF_MAP && pfn_valid(pfn: fr_pfn)) {
1626	struct page *page = pfn_to_page(fr_pfn);
1627
1628	memory_bm_clear_current(bm: forbidden_pages_map);
1629	memory_bm_clear_current(bm: free_pages_map);
1630	hibernate_restore_unprotect_page(page_address(page));
1631	__free_page(page);
1632	goto loop;
1633	}
1634
1635	out:
1636	nr_copy_pages = 0;
1637	nr_meta_pages = 0;
1638	nr_zero_pages = 0;
1639	restore_pblist = NULL;
1640	buffer = NULL;
1641	alloc_normal = 0;
1642	alloc_highmem = 0;
1643	hibernate_restore_protection_end();
1644	}
1645
1646	/* Helper functions used for the shrinking of memory. */
1647
1648	#define GFP_IMAGE (GFP_KERNEL | __GFP_NOWARN)
1649
1650	/**
1651	* preallocate_image_pages - Allocate a number of pages for hibernation image.
1652	* @nr_pages: Number of page frames to allocate.
1653	* @mask: GFP flags to use for the allocation.
1654	*
1655	* Return value: Number of page frames actually allocated
1656	*/
1657	static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1658	{
1659	unsigned long nr_alloc = 0;
1660
1661	while (nr_pages > 0) {
1662	struct page *page;
1663
1664	page = alloc_image_page(gfp_mask: mask);
1665	if (!page)
1666	break;
1667	memory_bm_set_bit(bm: &copy_bm, page_to_pfn(page));
1668	if (PageHighMem(page))
1669	alloc_highmem++;
1670	else
1671	alloc_normal++;
1672	nr_pages--;
1673	nr_alloc++;
1674	}
1675
1676	return nr_alloc;
1677	}
1678
1679	static unsigned long preallocate_image_memory(unsigned long nr_pages,
1680	unsigned long avail_normal)
1681	{
1682	unsigned long alloc;
1683
1684	if (avail_normal <= alloc_normal)
1685	return 0;
1686
1687	alloc = avail_normal - alloc_normal;
1688	if (nr_pages < alloc)
1689	alloc = nr_pages;
1690
1691	return preallocate_image_pages(nr_pages: alloc, GFP_IMAGE);
1692	}
1693
1694	#ifdef CONFIG_HIGHMEM
1695	static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1696	{
1697	return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1698	}
1699
1700	/**
1701	* __fraction - Compute (an approximation of) x * (multiplier / base).
1702	*/
1703	static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1704	{
1705	return div64_u64(x * multiplier, base);
1706	}
1707
1708	static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1709	unsigned long highmem,
1710	unsigned long total)
1711	{
1712	unsigned long alloc = __fraction(nr_pages, highmem, total);
1713
1714	return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1715	}
1716	#else /* CONFIG_HIGHMEM */
1717	static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1718	{
1719	return 0;
1720	}
1721
1722	static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1723	unsigned long highmem,
1724	unsigned long total)
1725	{
1726	return 0;
1727	}
1728	#endif /* CONFIG_HIGHMEM */
1729
1730	/**
1731	* free_unnecessary_pages - Release preallocated pages not needed for the image.
1732	*/
1733	static unsigned long free_unnecessary_pages(void)
1734	{
1735	unsigned long save, to_free_normal, to_free_highmem, free;
1736
1737	save = count_data_pages();
1738	if (alloc_normal >= save) {
1739	to_free_normal = alloc_normal - save;
1740	save = 0;
1741	} else {
1742	to_free_normal = 0;
1743	save -= alloc_normal;
1744	}
1745	save += count_highmem_pages();
1746	if (alloc_highmem >= save) {
1747	to_free_highmem = alloc_highmem - save;
1748	} else {
1749	to_free_highmem = 0;
1750	save -= alloc_highmem;
1751	if (to_free_normal > save)
1752	to_free_normal -= save;
1753	else
1754	to_free_normal = 0;
1755	}
1756	free = to_free_normal + to_free_highmem;
1757
1758	memory_bm_position_reset(bm: &copy_bm);
1759
1760	while (to_free_normal > 0 || to_free_highmem > 0) {
1761	unsigned long pfn = memory_bm_next_pfn(bm: &copy_bm);
1762	struct page *page = pfn_to_page(pfn);
1763
1764	if (PageHighMem(page)) {
1765	if (!to_free_highmem)
1766	continue;
1767	to_free_highmem--;
1768	alloc_highmem--;
1769	} else {
1770	if (!to_free_normal)
1771	continue;
1772	to_free_normal--;
1773	alloc_normal--;
1774	}
1775	memory_bm_clear_bit(bm: &copy_bm, pfn);
1776	swsusp_unset_page_forbidden(page);
1777	swsusp_unset_page_free(page);
1778	__free_page(page);
1779	}
1780
1781	return free;
1782	}
1783
1784	/**
1785	* minimum_image_size - Estimate the minimum acceptable size of an image.
1786	* @saveable: Number of saveable pages in the system.
1787	*
1788	* We want to avoid attempting to free too much memory too hard, so estimate the
1789	* minimum acceptable size of a hibernation image to use as the lower limit for
1790	* preallocating memory.
1791	*
1792	* We assume that the minimum image size should be proportional to
1793	*
1794	* [number of saveable pages] - [number of pages that can be freed in theory]
1795	*
1796	* where the second term is the sum of (1) reclaimable slab pages, (2) active
1797	* and (3) inactive anonymous pages, (4) active and (5) inactive file pages.
1798	*/
1799	static unsigned long minimum_image_size(unsigned long saveable)
1800	{
1801	unsigned long size;
1802
1803	size = global_node_page_state_pages(item: NR_SLAB_RECLAIMABLE_B)
1804	+ global_node_page_state(item: NR_ACTIVE_ANON)
1805	+ global_node_page_state(item: NR_INACTIVE_ANON)
1806	+ global_node_page_state(item: NR_ACTIVE_FILE)
1807	+ global_node_page_state(item: NR_INACTIVE_FILE);
1808
1809	return saveable <= size ? 0 : saveable - size;
1810	}
1811
1812	/**
1813	* hibernate_preallocate_memory - Preallocate memory for hibernation image.
1814	*
1815	* To create a hibernation image it is necessary to make a copy of every page
1816	* frame in use. We also need a number of page frames to be free during
1817	* hibernation for allocations made while saving the image and for device
1818	* drivers, in case they need to allocate memory from their hibernation
1819	* callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
1820	* estimate) and reserved_size divided by PAGE_SIZE (which is tunable through
1821	* /sys/power/reserved_size, respectively). To make this happen, we compute the
1822	* total number of available page frames and allocate at least
1823	*
1824	* ([page frames total] - PAGES_FOR_IO - [metadata pages]) / 2
1825	* - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
1826	*
1827	* of them, which corresponds to the maximum size of a hibernation image.
1828	*
1829	* If image_size is set below the number following from the above formula,
1830	* the preallocation of memory is continued until the total number of saveable
1831	* pages in the system is below the requested image size or the minimum
1832	* acceptable image size returned by minimum_image_size(), whichever is greater.
1833	*/
1834	int hibernate_preallocate_memory(void)
1835	{
1836	struct zone *zone;
1837	unsigned long saveable, size, max_size, count, highmem, pages = 0;
1838	unsigned long alloc, save_highmem, pages_highmem, avail_normal;
1839	ktime_t start, stop;
1840	int error;
1841
1842	pr_info("Preallocating image memory\n");
1843	start = ktime_get();
1844
1845	error = memory_bm_create(bm: &orig_bm, GFP_IMAGE, PG_ANY);
1846	if (error) {
1847	pr_err("Cannot allocate original bitmap\n");
1848	goto err_out;
1849	}
1850
1851	error = memory_bm_create(bm: &copy_bm, GFP_IMAGE, PG_ANY);
1852	if (error) {
1853	pr_err("Cannot allocate copy bitmap\n");
1854	goto err_out;
1855	}
1856
1857	error = memory_bm_create(bm: &zero_bm, GFP_IMAGE, PG_ANY);
1858	if (error) {
1859	pr_err("Cannot allocate zero bitmap\n");
1860	goto err_out;
1861	}
1862
1863	alloc_normal = 0;
1864	alloc_highmem = 0;
1865	nr_zero_pages = 0;
1866
1867	/* Count the number of saveable data pages. */
1868	save_highmem = count_highmem_pages();
1869	saveable = count_data_pages();
1870
1871	/*
1872	* Compute the total number of page frames we can use (count) and the
1873	* number of pages needed for image metadata (size).
1874	*/
1875	count = saveable;
1876	saveable += save_highmem;
1877	highmem = save_highmem;
1878	size = 0;
1879	for_each_populated_zone(zone) {
1880	size += snapshot_additional_pages(zone);
1881	if (is_highmem(zone))
1882	highmem += zone_page_state(zone, item: NR_FREE_PAGES);
1883	else
1884	count += zone_page_state(zone, item: NR_FREE_PAGES);
1885	}
1886	avail_normal = count;
1887	count += highmem;
1888	count -= totalreserve_pages;
1889
1890	/* Compute the maximum number of saveable pages to leave in memory. */
1891	max_size = (count - (size + PAGES_FOR_IO)) / 2
1892	- 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
1893	/* Compute the desired number of image pages specified by image_size. */
1894	size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1895	if (size > max_size)
1896	size = max_size;
1897	/*
1898	* If the desired number of image pages is at least as large as the
1899	* current number of saveable pages in memory, allocate page frames for
1900	* the image and we're done.
1901	*/
1902	if (size >= saveable) {
1903	pages = preallocate_image_highmem(nr_pages: save_highmem);
1904	pages += preallocate_image_memory(nr_pages: saveable - pages, avail_normal);
1905	goto out;
1906	}
1907
1908	/* Estimate the minimum size of the image. */
1909	pages = minimum_image_size(saveable);
1910	/*
1911	* To avoid excessive pressure on the normal zone, leave room in it to
1912	* accommodate an image of the minimum size (unless it's already too
1913	* small, in which case don't preallocate pages from it at all).
1914	*/
1915	if (avail_normal > pages)
1916	avail_normal -= pages;
1917	else
1918	avail_normal = 0;
1919	if (size < pages)
1920	size = min_t(unsigned long, pages, max_size);
1921
1922	/*
1923	* Let the memory management subsystem know that we're going to need a
1924	* large number of page frames to allocate and make it free some memory.
1925	* NOTE: If this is not done, performance will be hurt badly in some
1926	* test cases.
1927	*/
1928	shrink_all_memory(nr_pages: saveable - size);
1929
1930	/*
1931	* The number of saveable pages in memory was too high, so apply some
1932	* pressure to decrease it. First, make room for the largest possible
1933	* image and fail if that doesn't work. Next, try to decrease the size
1934	* of the image as much as indicated by 'size' using allocations from
1935	* highmem and non-highmem zones separately.
1936	*/
1937	pages_highmem = preallocate_image_highmem(nr_pages: highmem / 2);
1938	alloc = count - max_size;
1939	if (alloc > pages_highmem)
1940	alloc -= pages_highmem;
1941	else
1942	alloc = 0;
1943	pages = preallocate_image_memory(nr_pages: alloc, avail_normal);
1944	if (pages < alloc) {
1945	/* We have exhausted non-highmem pages, try highmem. */
1946	alloc -= pages;
1947	pages += pages_highmem;
1948	pages_highmem = preallocate_image_highmem(nr_pages: alloc);
1949	if (pages_highmem < alloc) {
1950	pr_err("Image allocation is %lu pages short\n",
1951	alloc - pages_highmem);
1952	goto err_out;
1953	}
1954	pages += pages_highmem;
1955	/*
1956	* size is the desired number of saveable pages to leave in
1957	* memory, so try to preallocate (all memory - size) pages.
1958	*/
1959	alloc = (count - pages) - size;
1960	pages += preallocate_image_highmem(nr_pages: alloc);
1961	} else {
1962	/*
1963	* There are approximately max_size saveable pages at this point
1964	* and we want to reduce this number down to size.
1965	*/
1966	alloc = max_size - size;
1967	size = preallocate_highmem_fraction(nr_pages: alloc, highmem, total: count);
1968	pages_highmem += size;
1969	alloc -= size;
1970	size = preallocate_image_memory(nr_pages: alloc, avail_normal);
1971	pages_highmem += preallocate_image_highmem(nr_pages: alloc - size);
1972	pages += pages_highmem + size;
1973	}
1974
1975	/*
1976	* We only need as many page frames for the image as there are saveable
1977	* pages in memory, but we have allocated more. Release the excessive
1978	* ones now.
1979	*/
1980	pages -= free_unnecessary_pages();
1981
1982	out:
1983	stop = ktime_get();
1984	pr_info("Allocated %lu pages for snapshot\n", pages);
1985	swsusp_show_speed(start, stop, pages, "Allocated");
1986
1987	return 0;
1988
1989	err_out:
1990	swsusp_free();
1991	return -ENOMEM;
1992	}
1993
1994	#ifdef CONFIG_HIGHMEM
1995	/**
1996	* count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
1997	*
1998	* Compute the number of non-highmem pages that will be necessary for creating
1999	* copies of highmem pages.
2000	*/
2001	static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
2002	{
2003	unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
2004
2005	if (free_highmem >= nr_highmem)
2006	nr_highmem = 0;
2007	else
2008	nr_highmem -= free_highmem;
2009
2010	return nr_highmem;
2011	}
2012	#else
2013	static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
2014	#endif /* CONFIG_HIGHMEM */
2015
2016	/**
2017	* enough_free_mem - Check if there is enough free memory for the image.
2018	*/
2019	static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
2020	{
2021	struct zone *zone;
2022	unsigned int free = alloc_normal;
2023
2024	for_each_populated_zone(zone)
2025	if (!is_highmem(zone))
2026	free += zone_page_state(zone, item: NR_FREE_PAGES);
2027
2028	nr_pages += count_pages_for_highmem(nr_highmem);
2029	pr_debug("Normal pages needed: %u + %u, available pages: %u\n",
2030	nr_pages, PAGES_FOR_IO, free);
2031
2032	return free > nr_pages + PAGES_FOR_IO;
2033	}
2034
2035	#ifdef CONFIG_HIGHMEM
2036	/**
2037	* get_highmem_buffer - Allocate a buffer for highmem pages.
2038	*
2039	* If there are some highmem pages in the hibernation image, we may need a
2040	* buffer to copy them and/or load their data.
2041	*/
2042	static inline int get_highmem_buffer(int safe_needed)
2043	{
2044	buffer = get_image_page(GFP_ATOMIC, safe_needed);
2045	return buffer ? 0 : -ENOMEM;
2046	}
2047
2048	/**
2049	* alloc_highmem_pages - Allocate some highmem pages for the image.
2050	*
2051	* Try to allocate as many pages as needed, but if the number of free highmem
2052	* pages is less than that, allocate them all.
2053	*/
2054	static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
2055	unsigned int nr_highmem)
2056	{
2057	unsigned int to_alloc = count_free_highmem_pages();
2058
2059	if (to_alloc > nr_highmem)
2060	to_alloc = nr_highmem;
2061
2062	nr_highmem -= to_alloc;
2063	while (to_alloc-- > 0) {
2064	struct page *page;
2065
2066	page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM);
2067	memory_bm_set_bit(bm, page_to_pfn(page));
2068	}
2069	return nr_highmem;
2070	}
2071	#else
2072	static inline int get_highmem_buffer(int safe_needed) { return 0; }
2073
2074	static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
2075	unsigned int n) { return 0; }
2076	#endif /* CONFIG_HIGHMEM */
2077
2078	/**
2079	* swsusp_alloc - Allocate memory for hibernation image.
2080	*
2081	* We first try to allocate as many highmem pages as there are
2082	* saveable highmem pages in the system. If that fails, we allocate
2083	* non-highmem pages for the copies of the remaining highmem ones.
2084	*
2085	* In this approach it is likely that the copies of highmem pages will
2086	* also be located in the high memory, because of the way in which
2087	* copy_data_pages() works.
2088	*/
2089	static int swsusp_alloc(struct memory_bitmap *copy_bm,
2090	unsigned int nr_pages, unsigned int nr_highmem)
2091	{
2092	if (nr_highmem > 0) {
2093	if (get_highmem_buffer(PG_ANY))
2094	goto err_out;
2095	if (nr_highmem > alloc_highmem) {
2096	nr_highmem -= alloc_highmem;
2097	nr_pages += alloc_highmem_pages(bm: copy_bm, n: nr_highmem);
2098	}
2099	}
2100	if (nr_pages > alloc_normal) {
2101	nr_pages -= alloc_normal;
2102	while (nr_pages-- > 0) {
2103	struct page *page;
2104
2105	page = alloc_image_page(GFP_ATOMIC);
2106	if (!page)
2107	goto err_out;
2108	memory_bm_set_bit(bm: copy_bm, page_to_pfn(page));
2109	}
2110	}
2111
2112	return 0;
2113
2114	err_out:
2115	swsusp_free();
2116	return -ENOMEM;
2117	}
2118
2119	asmlinkage __visible int swsusp_save(void)
2120	{
2121	unsigned int nr_pages, nr_highmem;
2122
2123	pr_info("Creating image:\n");
2124
2125	drain_local_pages(NULL);
2126	nr_pages = count_data_pages();
2127	nr_highmem = count_highmem_pages();
2128	pr_info("Need to copy %u pages\n", nr_pages + nr_highmem);
2129
2130	if (!enough_free_mem(nr_pages, nr_highmem)) {
2131	pr_err("Not enough free memory\n");
2132	return -ENOMEM;
2133	}
2134
2135	if (swsusp_alloc(copy_bm: &copy_bm, nr_pages, nr_highmem)) {
2136	pr_err("Memory allocation failed\n");
2137	return -ENOMEM;
2138	}
2139
2140	/*
2141	* During allocating of suspend pagedir, new cold pages may appear.
2142	* Kill them.
2143	*/
2144	drain_local_pages(NULL);
2145	nr_copy_pages = copy_data_pages(copy_bm: &copy_bm, orig_bm: &orig_bm, zero_bm: &zero_bm);
2146
2147	/*
2148	* End of critical section. From now on, we can write to memory,
2149	* but we should not touch disk. This specially means we must _not_
2150	* touch swap space! Except we must write out our image of course.
2151	*/
2152	nr_pages += nr_highmem;
2153	/* We don't actually copy the zero pages */
2154	nr_zero_pages = nr_pages - nr_copy_pages;
2155	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
2156
2157	pr_info("Image created (%d pages copied, %d zero pages)\n", nr_copy_pages, nr_zero_pages);
2158
2159	return 0;
2160	}
2161
2162	#ifndef CONFIG_ARCH_HIBERNATION_HEADER
2163	static int init_header_complete(struct swsusp_info *info)
2164	{
2165	memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
2166	info->version_code = LINUX_VERSION_CODE;
2167	return 0;
2168	}
2169
2170	static const char *check_image_kernel(struct swsusp_info *info)
2171	{
2172	if (info->version_code != LINUX_VERSION_CODE)
2173	return "kernel version";
2174	if (strcmp(info->uts.sysname,init_utsname()->sysname))
2175	return "system type";
2176	if (strcmp(info->uts.release,init_utsname()->release))
2177	return "kernel release";
2178	if (strcmp(info->uts.version,init_utsname()->version))
2179	return "version";
2180	if (strcmp(info->uts.machine,init_utsname()->machine))
2181	return "machine";
2182	return NULL;
2183	}
2184	#endif /* CONFIG_ARCH_HIBERNATION_HEADER */
2185
2186	unsigned long snapshot_get_image_size(void)
2187	{
2188	return nr_copy_pages + nr_meta_pages + 1;
2189	}
2190
2191	static int init_header(struct swsusp_info *info)
2192	{
2193	memset(info, 0, sizeof(struct swsusp_info));
2194	info->num_physpages = get_num_physpages();
2195	info->image_pages = nr_copy_pages;
2196	info->pages = snapshot_get_image_size();
2197	info->size = info->pages;
2198	info->size <<= PAGE_SHIFT;
2199	return init_header_complete(info);
2200	}
2201
2202	#define ENCODED_PFN_ZERO_FLAG ((unsigned long)1 << (BITS_PER_LONG - 1))
2203	#define ENCODED_PFN_MASK (~ENCODED_PFN_ZERO_FLAG)
2204
2205	/**
2206	* pack_pfns - Prepare PFNs for saving.
2207	* @bm: Memory bitmap.
2208	* @buf: Memory buffer to store the PFNs in.
2209	* @zero_bm: Memory bitmap containing PFNs of zero pages.
2210	*
2211	* PFNs corresponding to set bits in @bm are stored in the area of memory
2212	* pointed to by @buf (1 page at a time). Pages which were filled with only
2213	* zeros will have the highest bit set in the packed format to distinguish
2214	* them from PFNs which will be contained in the image file.
2215	*/
2216	static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm,
2217	struct memory_bitmap *zero_bm)
2218	{
2219	int j;
2220
2221	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2222	buf[j] = memory_bm_next_pfn(bm);
2223	if (unlikely(buf[j] == BM_END_OF_MAP))
2224	break;
2225	if (memory_bm_test_bit(bm: zero_bm, pfn: buf[j]))
2226	buf[j] |= ENCODED_PFN_ZERO_FLAG;
2227	}
2228	}
2229
2230	/**
2231	* snapshot_read_next - Get the address to read the next image page from.
2232	* @handle: Snapshot handle to be used for the reading.
2233	*
2234	* On the first call, @handle should point to a zeroed snapshot_handle
2235	* structure. The structure gets populated then and a pointer to it should be
2236	* passed to this function every next time.
2237	*
2238	* On success, the function returns a positive number. Then, the caller
2239	* is allowed to read up to the returned number of bytes from the memory
2240	* location computed by the data_of() macro.
2241	*
2242	* The function returns 0 to indicate the end of the data stream condition,
2243	* and negative numbers are returned on errors. If that happens, the structure
2244	* pointed to by @handle is not updated and should not be used any more.
2245	*/
2246	int snapshot_read_next(struct snapshot_handle *handle)
2247	{
2248	if (handle->cur > nr_meta_pages + nr_copy_pages)
2249	return 0;
2250
2251	if (!buffer) {
2252	/* This makes the buffer be freed by swsusp_free() */
2253	buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2254	if (!buffer)
2255	return -ENOMEM;
2256	}
2257	if (!handle->cur) {
2258	int error;
2259
2260	error = init_header(info: (struct swsusp_info *)buffer);
2261	if (error)
2262	return error;
2263	handle->buffer = buffer;
2264	memory_bm_position_reset(bm: &orig_bm);
2265	memory_bm_position_reset(bm: &copy_bm);
2266	} else if (handle->cur <= nr_meta_pages) {
2267	clear_page(page: buffer);
2268	pack_pfns(buf: buffer, bm: &orig_bm, zero_bm: &zero_bm);
2269	} else {
2270	struct page *page;
2271
2272	page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
2273	if (PageHighMem(page)) {
2274	/*
2275	* Highmem pages are copied to the buffer,
2276	* because we can't return with a kmapped
2277	* highmem page (we may not be called again).
2278	*/
2279	void *kaddr;
2280
2281	kaddr = kmap_atomic(page);
2282	copy_page(to: buffer, from: kaddr);
2283	kunmap_atomic(kaddr);
2284	handle->buffer = buffer;
2285	} else {
2286	handle->buffer = page_address(page);
2287	}
2288	}
2289	handle->cur++;
2290	return PAGE_SIZE;
2291	}
2292
2293	static void duplicate_memory_bitmap(struct memory_bitmap *dst,
2294	struct memory_bitmap *src)
2295	{
2296	unsigned long pfn;
2297
2298	memory_bm_position_reset(bm: src);
2299	pfn = memory_bm_next_pfn(bm: src);
2300	while (pfn != BM_END_OF_MAP) {
2301	memory_bm_set_bit(bm: dst, pfn);
2302	pfn = memory_bm_next_pfn(bm: src);
2303	}
2304	}
2305
2306	/**
2307	* mark_unsafe_pages - Mark pages that were used before hibernation.
2308	*
2309	* Mark the pages that cannot be used for storing the image during restoration,
2310	* because they conflict with the pages that had been used before hibernation.
2311	*/
2312	static void mark_unsafe_pages(struct memory_bitmap *bm)
2313	{
2314	unsigned long pfn;
2315
2316	/* Clear the "free"/"unsafe" bit for all PFNs */
2317	memory_bm_position_reset(bm: free_pages_map);
2318	pfn = memory_bm_next_pfn(bm: free_pages_map);
2319	while (pfn != BM_END_OF_MAP) {
2320	memory_bm_clear_current(bm: free_pages_map);
2321	pfn = memory_bm_next_pfn(bm: free_pages_map);
2322	}
2323
2324	/* Mark pages that correspond to the "original" PFNs as "unsafe" */
2325	duplicate_memory_bitmap(dst: free_pages_map, src: bm);
2326
2327	allocated_unsafe_pages = 0;
2328	}
2329
2330	static int check_header(struct swsusp_info *info)
2331	{
2332	const char *reason;
2333
2334	reason = check_image_kernel(info);
2335	if (!reason && info->num_physpages != get_num_physpages())
2336	reason = "memory size";
2337	if (reason) {
2338	pr_err("Image mismatch: %s\n", reason);
2339	return -EPERM;
2340	}
2341	return 0;
2342	}
2343
2344	/**
2345	* load_header - Check the image header and copy the data from it.
2346	*/
2347	static int load_header(struct swsusp_info *info)
2348	{
2349	int error;
2350
2351	restore_pblist = NULL;
2352	error = check_header(info);
2353	if (!error) {
2354	nr_copy_pages = info->image_pages;
2355	nr_meta_pages = info->pages - info->image_pages - 1;
2356	}
2357	return error;
2358	}
2359
2360	/**
2361	* unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
2362	* @bm: Memory bitmap.
2363	* @buf: Area of memory containing the PFNs.
2364	* @zero_bm: Memory bitmap with the zero PFNs marked.
2365	*
2366	* For each element of the array pointed to by @buf (1 page at a time), set the
2367	* corresponding bit in @bm. If the page was originally populated with only
2368	* zeros then a corresponding bit will also be set in @zero_bm.
2369	*/
2370	static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm,
2371	struct memory_bitmap *zero_bm)
2372	{
2373	unsigned long decoded_pfn;
2374	bool zero;
2375	int j;
2376
2377	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2378	if (unlikely(buf[j] == BM_END_OF_MAP))
2379	break;
2380
2381	zero = !!(buf[j] & ENCODED_PFN_ZERO_FLAG);
2382	decoded_pfn = buf[j] & ENCODED_PFN_MASK;
2383	if (pfn_valid(pfn: decoded_pfn) && memory_bm_pfn_present(bm, pfn: decoded_pfn)) {
2384	memory_bm_set_bit(bm, pfn: decoded_pfn);
2385	if (zero) {
2386	memory_bm_set_bit(bm: zero_bm, pfn: decoded_pfn);
2387	nr_zero_pages++;
2388	}
2389	} else {
2390	if (!pfn_valid(pfn: decoded_pfn))
2391	pr_err(FW_BUG "Memory map mismatch at 0x%llx after hibernation\n",
2392	(unsigned long long)PFN_PHYS(decoded_pfn));
2393	return -EFAULT;
2394	}
2395	}
2396
2397	return 0;
2398	}
2399
2400	#ifdef CONFIG_HIGHMEM
2401	/*
2402	* struct highmem_pbe is used for creating the list of highmem pages that
2403	* should be restored atomically during the resume from disk, because the page
2404	* frames they have occupied before the suspend are in use.
2405	*/
2406	struct highmem_pbe {
2407	struct page *copy_page; /* data is here now */
2408	struct page *orig_page; /* data was here before the suspend */
2409	struct highmem_pbe *next;
2410	};
2411
2412	/*
2413	* List of highmem PBEs needed for restoring the highmem pages that were
2414	* allocated before the suspend and included in the suspend image, but have
2415	* also been allocated by the "resume" kernel, so their contents cannot be
2416	* written directly to their "original" page frames.
2417	*/
2418	static struct highmem_pbe *highmem_pblist;
2419
2420	/**
2421	* count_highmem_image_pages - Compute the number of highmem pages in the image.
2422	* @bm: Memory bitmap.
2423	*
2424	* The bits in @bm that correspond to image pages are assumed to be set.
2425	*/
2426	static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
2427	{
2428	unsigned long pfn;
2429	unsigned int cnt = 0;
2430
2431	memory_bm_position_reset(bm);
2432	pfn = memory_bm_next_pfn(bm);
2433	while (pfn != BM_END_OF_MAP) {
2434	if (PageHighMem(pfn_to_page(pfn)))
2435	cnt++;
2436
2437	pfn = memory_bm_next_pfn(bm);
2438	}
2439	return cnt;
2440	}
2441
2442	static unsigned int safe_highmem_pages;
2443
2444	static struct memory_bitmap *safe_highmem_bm;
2445
2446	/**
2447	* prepare_highmem_image - Allocate memory for loading highmem data from image.
2448	* @bm: Pointer to an uninitialized memory bitmap structure.
2449	* @nr_highmem_p: Pointer to the number of highmem image pages.
2450	*
2451	* Try to allocate as many highmem pages as there are highmem image pages
2452	* (@nr_highmem_p points to the variable containing the number of highmem image
2453	* pages). The pages that are "safe" (ie. will not be overwritten when the
2454	* hibernation image is restored entirely) have the corresponding bits set in
2455	* @bm (it must be uninitialized).
2456	*
2457	* NOTE: This function should not be called if there are no highmem image pages.
2458	*/
2459	static int prepare_highmem_image(struct memory_bitmap *bm,
2460	unsigned int *nr_highmem_p)
2461	{
2462	unsigned int to_alloc;
2463
2464	if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
2465	return -ENOMEM;
2466
2467	if (get_highmem_buffer(PG_SAFE))
2468	return -ENOMEM;
2469
2470	to_alloc = count_free_highmem_pages();
2471	if (to_alloc > *nr_highmem_p)
2472	to_alloc = *nr_highmem_p;
2473	else
2474	*nr_highmem_p = to_alloc;
2475
2476	safe_highmem_pages = 0;
2477	while (to_alloc-- > 0) {
2478	struct page *page;
2479
2480	page = alloc_page(__GFP_HIGHMEM);
2481	if (!swsusp_page_is_free(page)) {
2482	/* The page is "safe", set its bit the bitmap */
2483	memory_bm_set_bit(bm, page_to_pfn(page));
2484	safe_highmem_pages++;
2485	}
2486	/* Mark the page as allocated */
2487	swsusp_set_page_forbidden(page);
2488	swsusp_set_page_free(page);
2489	}
2490	memory_bm_position_reset(bm);
2491	safe_highmem_bm = bm;
2492	return 0;
2493	}
2494
2495	static struct page *last_highmem_page;
2496
2497	/**
2498	* get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
2499	*
2500	* For a given highmem image page get a buffer that suspend_write_next() should
2501	* return to its caller to write to.
2502	*
2503	* If the page is to be saved to its "original" page frame or a copy of
2504	* the page is to be made in the highmem, @buffer is returned. Otherwise,
2505	* the copy of the page is to be made in normal memory, so the address of
2506	* the copy is returned.
2507	*
2508	* If @buffer is returned, the caller of suspend_write_next() will write
2509	* the page's contents to @buffer, so they will have to be copied to the
2510	* right location on the next call to suspend_write_next() and it is done
2511	* with the help of copy_last_highmem_page(). For this purpose, if
2512	* @buffer is returned, @last_highmem_page is set to the page to which
2513	* the data will have to be copied from @buffer.
2514	*/
2515	static void *get_highmem_page_buffer(struct page *page,
2516	struct chain_allocator *ca)
2517	{
2518	struct highmem_pbe *pbe;
2519	void *kaddr;
2520
2521	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
2522	/*
2523	* We have allocated the "original" page frame and we can
2524	* use it directly to store the loaded page.
2525	*/
2526	last_highmem_page = page;
2527	return buffer;
2528	}
2529	/*
2530	* The "original" page frame has not been allocated and we have to
2531	* use a "safe" page frame to store the loaded page.
2532	*/
2533	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
2534	if (!pbe) {
2535	swsusp_free();
2536	return ERR_PTR(-ENOMEM);
2537	}
2538	pbe->orig_page = page;
2539	if (safe_highmem_pages > 0) {
2540	struct page *tmp;
2541
2542	/* Copy of the page will be stored in high memory */
2543	kaddr = buffer;
2544	tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
2545	safe_highmem_pages--;
2546	last_highmem_page = tmp;
2547	pbe->copy_page = tmp;
2548	} else {
2549	/* Copy of the page will be stored in normal memory */
2550	kaddr = __get_safe_page(ca->gfp_mask);
2551	if (!kaddr)
2552	return ERR_PTR(-ENOMEM);
2553	pbe->copy_page = virt_to_page(kaddr);
2554	}
2555	pbe->next = highmem_pblist;
2556	highmem_pblist = pbe;
2557	return kaddr;
2558	}
2559
2560	/**
2561	* copy_last_highmem_page - Copy most the most recent highmem image page.
2562	*
2563	* Copy the contents of a highmem image from @buffer, where the caller of
2564	* snapshot_write_next() has stored them, to the right location represented by
2565	* @last_highmem_page .
2566	*/
2567	static void copy_last_highmem_page(void)
2568	{
2569	if (last_highmem_page) {
2570	void *dst;
2571
2572	dst = kmap_atomic(last_highmem_page);
2573	copy_page(dst, buffer);
2574	kunmap_atomic(dst);
2575	last_highmem_page = NULL;
2576	}
2577	}
2578
2579	static inline int last_highmem_page_copied(void)
2580	{
2581	return !last_highmem_page;
2582	}
2583
2584	static inline void free_highmem_data(void)
2585	{
2586	if (safe_highmem_bm)
2587	memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
2588
2589	if (buffer)
2590	free_image_page(buffer, PG_UNSAFE_CLEAR);
2591	}
2592	#else
2593	static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
2594
2595	static inline int prepare_highmem_image(struct memory_bitmap *bm,
2596	unsigned int *nr_highmem_p) { return 0; }
2597
2598	static inline void *get_highmem_page_buffer(struct page *page,
2599	struct chain_allocator *ca)
2600	{
2601	return ERR_PTR(error: -EINVAL);
2602	}
2603
2604	static inline void copy_last_highmem_page(void) {}
2605	static inline int last_highmem_page_copied(void) { return 1; }
2606	static inline void free_highmem_data(void) {}
2607	#endif /* CONFIG_HIGHMEM */
2608
2609	#define PBES_PER_LINKED_PAGE (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
2610
2611	/**
2612	* prepare_image - Make room for loading hibernation image.
2613	* @new_bm: Uninitialized memory bitmap structure.
2614	* @bm: Memory bitmap with unsafe pages marked.
2615	* @zero_bm: Memory bitmap containing the zero pages.
2616	*
2617	* Use @bm to mark the pages that will be overwritten in the process of
2618	* restoring the system memory state from the suspend image ("unsafe" pages)
2619	* and allocate memory for the image.
2620	*
2621	* The idea is to allocate a new memory bitmap first and then allocate
2622	* as many pages as needed for image data, but without specifying what those
2623	* pages will be used for just yet. Instead, we mark them all as allocated and
2624	* create a lists of "safe" pages to be used later. On systems with high
2625	* memory a list of "safe" highmem pages is created too.
2626	*
2627	* Because it was not known which pages were unsafe when @zero_bm was created,
2628	* make a copy of it and recreate it within safe pages.
2629	*/
2630	static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm,
2631	struct memory_bitmap *zero_bm)
2632	{
2633	unsigned int nr_pages, nr_highmem;
2634	struct memory_bitmap tmp;
2635	struct linked_page *lp;
2636	int error;
2637
2638	/* If there is no highmem, the buffer will not be necessary */
2639	free_image_page(addr: buffer, PG_UNSAFE_CLEAR);
2640	buffer = NULL;
2641
2642	nr_highmem = count_highmem_image_pages(bm);
2643	mark_unsafe_pages(bm);
2644
2645	error = memory_bm_create(bm: new_bm, GFP_ATOMIC, PG_SAFE);
2646	if (error)
2647	goto Free;
2648
2649	duplicate_memory_bitmap(dst: new_bm, src: bm);
2650	memory_bm_free(bm, PG_UNSAFE_KEEP);
2651
2652	/* Make a copy of zero_bm so it can be created in safe pages */
2653	error = memory_bm_create(bm: &tmp, GFP_ATOMIC, PG_SAFE);
2654	if (error)
2655	goto Free;
2656
2657	duplicate_memory_bitmap(dst: &tmp, src: zero_bm);
2658	memory_bm_free(bm: zero_bm, PG_UNSAFE_KEEP);
2659
2660	/* Recreate zero_bm in safe pages */
2661	error = memory_bm_create(bm: zero_bm, GFP_ATOMIC, PG_SAFE);
2662	if (error)
2663	goto Free;
2664
2665	duplicate_memory_bitmap(dst: zero_bm, src: &tmp);
2666	memory_bm_free(bm: &tmp, PG_UNSAFE_CLEAR);
2667	/* At this point zero_bm is in safe pages and it can be used for restoring. */
2668
2669	if (nr_highmem > 0) {
2670	error = prepare_highmem_image(bm, nr_highmem_p: &nr_highmem);
2671	if (error)
2672	goto Free;
2673	}
2674	/*
2675	* Reserve some safe pages for potential later use.
2676	*
2677	* NOTE: This way we make sure there will be enough safe pages for the
2678	* chain_alloc() in get_buffer(). It is a bit wasteful, but
2679	* nr_copy_pages cannot be greater than 50% of the memory anyway.
2680	*
2681	* nr_copy_pages cannot be less than allocated_unsafe_pages too.
2682	*/
2683	nr_pages = (nr_zero_pages + nr_copy_pages) - nr_highmem - allocated_unsafe_pages;
2684	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
2685	while (nr_pages > 0) {
2686	lp = get_image_page(GFP_ATOMIC, PG_SAFE);
2687	if (!lp) {
2688	error = -ENOMEM;
2689	goto Free;
2690	}
2691	lp->next = safe_pages_list;
2692	safe_pages_list = lp;
2693	nr_pages--;
2694	}
2695	/* Preallocate memory for the image */
2696	nr_pages = (nr_zero_pages + nr_copy_pages) - nr_highmem - allocated_unsafe_pages;
2697	while (nr_pages > 0) {
2698	lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
2699	if (!lp) {
2700	error = -ENOMEM;
2701	goto Free;
2702	}
2703	if (!swsusp_page_is_free(virt_to_page(lp))) {
2704	/* The page is "safe", add it to the list */
2705	lp->next = safe_pages_list;
2706	safe_pages_list = lp;
2707	}
2708	/* Mark the page as allocated */
2709	swsusp_set_page_forbidden(virt_to_page(lp));
2710	swsusp_set_page_free(virt_to_page(lp));
2711	nr_pages--;
2712	}
2713	return 0;
2714
2715	Free:
2716	swsusp_free();
2717	return error;
2718	}
2719
2720	/**
2721	* get_buffer - Get the address to store the next image data page.
2722	*
2723	* Get the address that snapshot_write_next() should return to its caller to
2724	* write to.
2725	*/
2726	static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
2727	{
2728	struct pbe *pbe;
2729	struct page *page;
2730	unsigned long pfn = memory_bm_next_pfn(bm);
2731
2732	if (pfn == BM_END_OF_MAP)
2733	return ERR_PTR(error: -EFAULT);
2734
2735	page = pfn_to_page(pfn);
2736	if (PageHighMem(page))
2737	return get_highmem_page_buffer(page, ca);
2738
2739	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2740	/*
2741	* We have allocated the "original" page frame and we can
2742	* use it directly to store the loaded page.
2743	*/
2744	return page_address(page);
2745
2746	/*
2747	* The "original" page frame has not been allocated and we have to
2748	* use a "safe" page frame to store the loaded page.
2749	*/
2750	pbe = chain_alloc(ca, size: sizeof(struct pbe));
2751	if (!pbe) {
2752	swsusp_free();
2753	return ERR_PTR(error: -ENOMEM);
2754	}
2755	pbe->orig_address = page_address(page);
2756	pbe->address = __get_safe_page(gfp_mask: ca->gfp_mask);
2757	if (!pbe->address)
2758	return ERR_PTR(error: -ENOMEM);
2759	pbe->next = restore_pblist;
2760	restore_pblist = pbe;
2761	return pbe->address;
2762	}
2763
2764	/**
2765	* snapshot_write_next - Get the address to store the next image page.
2766	* @handle: Snapshot handle structure to guide the writing.
2767	*
2768	* On the first call, @handle should point to a zeroed snapshot_handle
2769	* structure. The structure gets populated then and a pointer to it should be
2770	* passed to this function every next time.
2771	*
2772	* On success, the function returns a positive number. Then, the caller
2773	* is allowed to write up to the returned number of bytes to the memory
2774	* location computed by the data_of() macro.
2775	*
2776	* The function returns 0 to indicate the "end of file" condition. Negative
2777	* numbers are returned on errors, in which cases the structure pointed to by
2778	* @handle is not updated and should not be used any more.
2779	*/
2780	int snapshot_write_next(struct snapshot_handle *handle)
2781	{
2782	static struct chain_allocator ca;
2783	int error;
2784
2785	next:
2786	/* Check if we have already loaded the entire image */
2787	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages)
2788	return 0;
2789
2790	if (!handle->cur) {
2791	if (!buffer)
2792	/* This makes the buffer be freed by swsusp_free() */
2793	buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2794
2795	if (!buffer)
2796	return -ENOMEM;
2797
2798	handle->buffer = buffer;
2799	} else if (handle->cur == 1) {
2800	error = load_header(info: buffer);
2801	if (error)
2802	return error;
2803
2804	safe_pages_list = NULL;
2805
2806	error = memory_bm_create(bm: &copy_bm, GFP_ATOMIC, PG_ANY);
2807	if (error)
2808	return error;
2809
2810	error = memory_bm_create(bm: &zero_bm, GFP_ATOMIC, PG_ANY);
2811	if (error)
2812	return error;
2813
2814	nr_zero_pages = 0;
2815
2816	hibernate_restore_protection_begin();
2817	} else if (handle->cur <= nr_meta_pages + 1) {
2818	error = unpack_orig_pfns(buf: buffer, bm: &copy_bm, zero_bm: &zero_bm);
2819	if (error)
2820	return error;
2821
2822	if (handle->cur == nr_meta_pages + 1) {
2823	error = prepare_image(new_bm: &orig_bm, bm: &copy_bm, zero_bm: &zero_bm);
2824	if (error)
2825	return error;
2826
2827	chain_init(ca: &ca, GFP_ATOMIC, PG_SAFE);
2828	memory_bm_position_reset(bm: &orig_bm);
2829	memory_bm_position_reset(bm: &zero_bm);
2830	restore_pblist = NULL;
2831	handle->buffer = get_buffer(bm: &orig_bm, ca: &ca);
2832	if (IS_ERR(ptr: handle->buffer))
2833	return PTR_ERR(ptr: handle->buffer);
2834	}
2835	} else {
2836	copy_last_highmem_page();
2837	error = hibernate_restore_protect_page(page_address: handle->buffer);
2838	if (error)
2839	return error;
2840	handle->buffer = get_buffer(bm: &orig_bm, ca: &ca);
2841	if (IS_ERR(ptr: handle->buffer))
2842	return PTR_ERR(ptr: handle->buffer);
2843	}
2844	handle->sync_read = (handle->buffer == buffer);
2845	handle->cur++;
2846
2847	/* Zero pages were not included in the image, memset it and move on. */
2848	if (handle->cur > nr_meta_pages + 1 &&
2849	memory_bm_test_bit(bm: &zero_bm, pfn: memory_bm_get_current(bm: &orig_bm))) {
2850	memset(handle->buffer, 0, PAGE_SIZE);
2851	goto next;
2852	}
2853
2854	return PAGE_SIZE;
2855	}
2856
2857	/**
2858	* snapshot_write_finalize - Complete the loading of a hibernation image.
2859	*
2860	* Must be called after the last call to snapshot_write_next() in case the last
2861	* page in the image happens to be a highmem page and its contents should be
2862	* stored in highmem. Additionally, it recycles bitmap memory that's not
2863	* necessary any more.
2864	*/
2865	int snapshot_write_finalize(struct snapshot_handle *handle)
2866	{
2867	int error;
2868
2869	copy_last_highmem_page();
2870	error = hibernate_restore_protect_page(page_address: handle->buffer);
2871	/* Do that only if we have loaded the image entirely */
2872	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages) {
2873	memory_bm_recycle(bm: &orig_bm);
2874	free_highmem_data();
2875	}
2876	return error;
2877	}
2878
2879	int snapshot_image_loaded(struct snapshot_handle *handle)
2880	{
2881	return !(!nr_copy_pages || !last_highmem_page_copied() ||
2882	handle->cur <= nr_meta_pages + nr_copy_pages + nr_zero_pages);
2883	}
2884
2885	#ifdef CONFIG_HIGHMEM
2886	/* Assumes that @buf is ready and points to a "safe" page */
2887	static inline void swap_two_pages_data(struct page *p1, struct page *p2,
2888	void *buf)
2889	{
2890	void *kaddr1, *kaddr2;
2891
2892	kaddr1 = kmap_atomic(p1);
2893	kaddr2 = kmap_atomic(p2);
2894	copy_page(buf, kaddr1);
2895	copy_page(kaddr1, kaddr2);
2896	copy_page(kaddr2, buf);
2897	kunmap_atomic(kaddr2);
2898	kunmap_atomic(kaddr1);
2899	}
2900
2901	/**
2902	* restore_highmem - Put highmem image pages into their original locations.
2903	*
2904	* For each highmem page that was in use before hibernation and is included in
2905	* the image, and also has been allocated by the "restore" kernel, swap its
2906	* current contents with the previous (ie. "before hibernation") ones.
2907	*
2908	* If the restore eventually fails, we can call this function once again and
2909	* restore the highmem state as seen by the restore kernel.
2910	*/
2911	int restore_highmem(void)
2912	{
2913	struct highmem_pbe *pbe = highmem_pblist;
2914	void *buf;
2915
2916	if (!pbe)
2917	return 0;
2918
2919	buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2920	if (!buf)
2921	return -ENOMEM;
2922
2923	while (pbe) {
2924	swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2925	pbe = pbe->next;
2926	}
2927	free_image_page(buf, PG_UNSAFE_CLEAR);
2928	return 0;
2929	}
2930	#endif /* CONFIG_HIGHMEM */
2931