xref: /openbmc/linux/kernel/power/snapshot.c (revision 07565045)
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 
enable_restore_image_protection(void)46 void enable_restore_image_protection(void)
47 {
48 	hibernate_restore_protection = true;
49 }
50 
hibernate_restore_protection_begin(void)51 static inline void hibernate_restore_protection_begin(void)
52 {
53 	hibernate_restore_protection_active = hibernate_restore_protection;
54 }
55 
hibernate_restore_protection_end(void)56 static inline void hibernate_restore_protection_end(void)
57 {
58 	hibernate_restore_protection_active = false;
59 }
60 
hibernate_restore_protect_page(void * page_address)61 static inline void hibernate_restore_protect_page(void *page_address)
62 {
63 	if (hibernate_restore_protection_active)
64 		set_memory_ro((unsigned long)page_address, 1);
65 }
66 
hibernate_restore_unprotect_page(void * page_address)67 static inline void hibernate_restore_unprotect_page(void *page_address)
68 {
69 	if (hibernate_restore_protection_active)
70 		set_memory_rw((unsigned long)page_address, 1);
71 }
72 #else
hibernate_restore_protection_begin(void)73 static inline void hibernate_restore_protection_begin(void) {}
hibernate_restore_protection_end(void)74 static inline void hibernate_restore_protection_end(void) {}
hibernate_restore_protect_page(void * page_address)75 static inline void hibernate_restore_protect_page(void *page_address) {}
hibernate_restore_unprotect_page(void * page_address)76 static inline void hibernate_restore_unprotect_page(void *page_address) {}
77 #endif /* CONFIG_STRICT_KERNEL_RWX  && CONFIG_ARCH_HAS_SET_MEMORY */
78 
79 
80 /*
81  * The calls to set_direct_map_*() should not fail because remapping a page
82  * here means that we only update protection bits in an existing PTE.
83  * It is still worth to have a warning here if something changes and this
84  * will no longer be the case.
85  */
hibernate_map_page(struct page * page)86 static inline void hibernate_map_page(struct page *page)
87 {
88 	if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
89 		int ret = set_direct_map_default_noflush(page);
90 
91 		if (ret)
92 			pr_warn_once("Failed to remap page\n");
93 	} else {
94 		debug_pagealloc_map_pages(page, 1);
95 	}
96 }
97 
hibernate_unmap_page(struct page * page)98 static inline void hibernate_unmap_page(struct page *page)
99 {
100 	if (IS_ENABLED(CONFIG_ARCH_HAS_SET_DIRECT_MAP)) {
101 		unsigned long addr = (unsigned long)page_address(page);
102 		int ret  = set_direct_map_invalid_noflush(page);
103 
104 		if (ret)
105 			pr_warn_once("Failed to remap page\n");
106 
107 		flush_tlb_kernel_range(addr, addr + PAGE_SIZE);
108 	} else {
109 		debug_pagealloc_unmap_pages(page, 1);
110 	}
111 }
112 
113 static int swsusp_page_is_free(struct page *);
114 static void swsusp_set_page_forbidden(struct page *);
115 static void swsusp_unset_page_forbidden(struct page *);
116 
117 /*
118  * Number of bytes to reserve for memory allocations made by device drivers
119  * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
120  * cause image creation to fail (tunable via /sys/power/reserved_size).
121  */
122 unsigned long reserved_size;
123 
hibernate_reserved_size_init(void)124 void __init hibernate_reserved_size_init(void)
125 {
126 	reserved_size = SPARE_PAGES * PAGE_SIZE;
127 }
128 
129 /*
130  * Preferred image size in bytes (tunable via /sys/power/image_size).
131  * When it is set to N, swsusp will do its best to ensure the image
132  * size will not exceed N bytes, but if that is impossible, it will
133  * try to create the smallest image possible.
134  */
135 unsigned long image_size;
136 
hibernate_image_size_init(void)137 void __init hibernate_image_size_init(void)
138 {
139 	image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
140 }
141 
142 /*
143  * List of PBEs needed for restoring the pages that were allocated before
144  * the suspend and included in the suspend image, but have also been
145  * allocated by the "resume" kernel, so their contents cannot be written
146  * directly to their "original" page frames.
147  */
148 struct pbe *restore_pblist;
149 
150 /* struct linked_page is used to build chains of pages */
151 
152 #define LINKED_PAGE_DATA_SIZE	(PAGE_SIZE - sizeof(void *))
153 
154 struct linked_page {
155 	struct linked_page *next;
156 	char data[LINKED_PAGE_DATA_SIZE];
157 } __packed;
158 
159 /*
160  * List of "safe" pages (ie. pages that were not used by the image kernel
161  * before hibernation) that may be used as temporary storage for image kernel
162  * memory contents.
163  */
164 static struct linked_page *safe_pages_list;
165 
166 /* Pointer to an auxiliary buffer (1 page) */
167 static void *buffer;
168 
169 #define PG_ANY		0
170 #define PG_SAFE		1
171 #define PG_UNSAFE_CLEAR	1
172 #define PG_UNSAFE_KEEP	0
173 
174 static unsigned int allocated_unsafe_pages;
175 
176 /**
177  * get_image_page - Allocate a page for a hibernation image.
178  * @gfp_mask: GFP mask for the allocation.
179  * @safe_needed: Get pages that were not used before hibernation (restore only)
180  *
181  * During image restoration, for storing the PBE list and the image data, we can
182  * only use memory pages that do not conflict with the pages used before
183  * hibernation.  The "unsafe" pages have PageNosaveFree set and we count them
184  * using allocated_unsafe_pages.
185  *
186  * Each allocated image page is marked as PageNosave and PageNosaveFree so that
187  * swsusp_free() can release it.
188  */
get_image_page(gfp_t gfp_mask,int safe_needed)189 static void *get_image_page(gfp_t gfp_mask, int safe_needed)
190 {
191 	void *res;
192 
193 	res = (void *)get_zeroed_page(gfp_mask);
194 	if (safe_needed)
195 		while (res && swsusp_page_is_free(virt_to_page(res))) {
196 			/* The page is unsafe, mark it for swsusp_free() */
197 			swsusp_set_page_forbidden(virt_to_page(res));
198 			allocated_unsafe_pages++;
199 			res = (void *)get_zeroed_page(gfp_mask);
200 		}
201 	if (res) {
202 		swsusp_set_page_forbidden(virt_to_page(res));
203 		swsusp_set_page_free(virt_to_page(res));
204 	}
205 	return res;
206 }
207 
__get_safe_page(gfp_t gfp_mask)208 static void *__get_safe_page(gfp_t gfp_mask)
209 {
210 	if (safe_pages_list) {
211 		void *ret = safe_pages_list;
212 
213 		safe_pages_list = safe_pages_list->next;
214 		memset(ret, 0, PAGE_SIZE);
215 		return ret;
216 	}
217 	return get_image_page(gfp_mask, PG_SAFE);
218 }
219 
get_safe_page(gfp_t gfp_mask)220 unsigned long get_safe_page(gfp_t gfp_mask)
221 {
222 	return (unsigned long)__get_safe_page(gfp_mask);
223 }
224 
alloc_image_page(gfp_t gfp_mask)225 static struct page *alloc_image_page(gfp_t gfp_mask)
226 {
227 	struct page *page;
228 
229 	page = alloc_page(gfp_mask);
230 	if (page) {
231 		swsusp_set_page_forbidden(page);
232 		swsusp_set_page_free(page);
233 	}
234 	return page;
235 }
236 
recycle_safe_page(void * page_address)237 static void recycle_safe_page(void *page_address)
238 {
239 	struct linked_page *lp = page_address;
240 
241 	lp->next = safe_pages_list;
242 	safe_pages_list = lp;
243 }
244 
245 /**
246  * free_image_page - Free a page allocated for hibernation image.
247  * @addr: Address of the page to free.
248  * @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
249  *
250  * The page to free should have been allocated by get_image_page() (page flags
251  * set by it are affected).
252  */
free_image_page(void * addr,int clear_nosave_free)253 static inline void free_image_page(void *addr, int clear_nosave_free)
254 {
255 	struct page *page;
256 
257 	BUG_ON(!virt_addr_valid(addr));
258 
259 	page = virt_to_page(addr);
260 
261 	swsusp_unset_page_forbidden(page);
262 	if (clear_nosave_free)
263 		swsusp_unset_page_free(page);
264 
265 	__free_page(page);
266 }
267 
free_list_of_pages(struct linked_page * list,int clear_page_nosave)268 static inline void free_list_of_pages(struct linked_page *list,
269 				      int clear_page_nosave)
270 {
271 	while (list) {
272 		struct linked_page *lp = list->next;
273 
274 		free_image_page(list, clear_page_nosave);
275 		list = lp;
276 	}
277 }
278 
279 /*
280  * struct chain_allocator is used for allocating small objects out of
281  * a linked list of pages called 'the chain'.
282  *
283  * The chain grows each time when there is no room for a new object in
284  * the current page.  The allocated objects cannot be freed individually.
285  * It is only possible to free them all at once, by freeing the entire
286  * chain.
287  *
288  * NOTE: The chain allocator may be inefficient if the allocated objects
289  * are not much smaller than PAGE_SIZE.
290  */
291 struct chain_allocator {
292 	struct linked_page *chain;	/* the chain */
293 	unsigned int used_space;	/* total size of objects allocated out
294 					   of the current page */
295 	gfp_t gfp_mask;		/* mask for allocating pages */
296 	int safe_needed;	/* if set, only "safe" pages are allocated */
297 };
298 
chain_init(struct chain_allocator * ca,gfp_t gfp_mask,int safe_needed)299 static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask,
300 		       int safe_needed)
301 {
302 	ca->chain = NULL;
303 	ca->used_space = LINKED_PAGE_DATA_SIZE;
304 	ca->gfp_mask = gfp_mask;
305 	ca->safe_needed = safe_needed;
306 }
307 
chain_alloc(struct chain_allocator * ca,unsigned int size)308 static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
309 {
310 	void *ret;
311 
312 	if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
313 		struct linked_page *lp;
314 
315 		lp = ca->safe_needed ? __get_safe_page(ca->gfp_mask) :
316 					get_image_page(ca->gfp_mask, PG_ANY);
317 		if (!lp)
318 			return NULL;
319 
320 		lp->next = ca->chain;
321 		ca->chain = lp;
322 		ca->used_space = 0;
323 	}
324 	ret = ca->chain->data + ca->used_space;
325 	ca->used_space += size;
326 	return ret;
327 }
328 
329 /*
330  * Data types related to memory bitmaps.
331  *
332  * Memory bitmap is a structure consisting of many linked lists of
333  * objects.  The main list's elements are of type struct zone_bitmap
334  * and each of them corresponds to one zone.  For each zone bitmap
335  * object there is a list of objects of type struct bm_block that
336  * represent each blocks of bitmap in which information is stored.
337  *
338  * struct memory_bitmap contains a pointer to the main list of zone
339  * bitmap objects, a struct bm_position used for browsing the bitmap,
340  * and a pointer to the list of pages used for allocating all of the
341  * zone bitmap objects and bitmap block objects.
342  *
343  * NOTE: It has to be possible to lay out the bitmap in memory
344  * using only allocations of order 0.  Additionally, the bitmap is
345  * designed to work with arbitrary number of zones (this is over the
346  * top for now, but let's avoid making unnecessary assumptions ;-).
347  *
348  * struct zone_bitmap contains a pointer to a list of bitmap block
349  * objects and a pointer to the bitmap block object that has been
350  * most recently used for setting bits.  Additionally, it contains the
351  * PFNs that correspond to the start and end of the represented zone.
352  *
353  * struct bm_block contains a pointer to the memory page in which
354  * information is stored (in the form of a block of bitmap)
355  * It also contains the pfns that correspond to the start and end of
356  * the represented memory area.
357  *
358  * The memory bitmap is organized as a radix tree to guarantee fast random
359  * access to the bits. There is one radix tree for each zone (as returned
360  * from create_mem_extents).
361  *
362  * One radix tree is represented by one struct mem_zone_bm_rtree. There are
363  * two linked lists for the nodes of the tree, one for the inner nodes and
364  * one for the leave nodes. The linked leave nodes are used for fast linear
365  * access of the memory bitmap.
366  *
367  * The struct rtree_node represents one node of the radix tree.
368  */
369 
370 #define BM_END_OF_MAP	(~0UL)
371 
372 #define BM_BITS_PER_BLOCK	(PAGE_SIZE * BITS_PER_BYTE)
373 #define BM_BLOCK_SHIFT		(PAGE_SHIFT + 3)
374 #define BM_BLOCK_MASK		((1UL << BM_BLOCK_SHIFT) - 1)
375 
376 /*
377  * struct rtree_node is a wrapper struct to link the nodes
378  * of the rtree together for easy linear iteration over
379  * bits and easy freeing
380  */
381 struct rtree_node {
382 	struct list_head list;
383 	unsigned long *data;
384 };
385 
386 /*
387  * struct mem_zone_bm_rtree represents a bitmap used for one
388  * populated memory zone.
389  */
390 struct mem_zone_bm_rtree {
391 	struct list_head list;		/* Link Zones together         */
392 	struct list_head nodes;		/* Radix Tree inner nodes      */
393 	struct list_head leaves;	/* Radix Tree leaves           */
394 	unsigned long start_pfn;	/* Zone start page frame       */
395 	unsigned long end_pfn;		/* Zone end page frame + 1     */
396 	struct rtree_node *rtree;	/* Radix Tree Root             */
397 	int levels;			/* Number of Radix Tree Levels */
398 	unsigned int blocks;		/* Number of Bitmap Blocks     */
399 };
400 
401 /* struct bm_position is used for browsing memory bitmaps */
402 
403 struct bm_position {
404 	struct mem_zone_bm_rtree *zone;
405 	struct rtree_node *node;
406 	unsigned long node_pfn;
407 	unsigned long cur_pfn;
408 	int node_bit;
409 };
410 
411 struct memory_bitmap {
412 	struct list_head zones;
413 	struct linked_page *p_list;	/* list of pages used to store zone
414 					   bitmap objects and bitmap block
415 					   objects */
416 	struct bm_position cur;	/* most recently used bit position */
417 };
418 
419 /* Functions that operate on memory bitmaps */
420 
421 #define BM_ENTRIES_PER_LEVEL	(PAGE_SIZE / sizeof(unsigned long))
422 #if BITS_PER_LONG == 32
423 #define BM_RTREE_LEVEL_SHIFT	(PAGE_SHIFT - 2)
424 #else
425 #define BM_RTREE_LEVEL_SHIFT	(PAGE_SHIFT - 3)
426 #endif
427 #define BM_RTREE_LEVEL_MASK	((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
428 
429 /**
430  * alloc_rtree_node - Allocate a new node and add it to the radix tree.
431  * @gfp_mask: GFP mask for the allocation.
432  * @safe_needed: Get pages not used before hibernation (restore only)
433  * @ca: Pointer to a linked list of pages ("a chain") to allocate from
434  * @list: Radix Tree node to add.
435  *
436  * This function is used to allocate inner nodes as well as the
437  * leave nodes of the radix tree. It also adds the node to the
438  * corresponding linked list passed in by the *list parameter.
439  */
alloc_rtree_node(gfp_t gfp_mask,int safe_needed,struct chain_allocator * ca,struct list_head * list)440 static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
441 					   struct chain_allocator *ca,
442 					   struct list_head *list)
443 {
444 	struct rtree_node *node;
445 
446 	node = chain_alloc(ca, sizeof(struct rtree_node));
447 	if (!node)
448 		return NULL;
449 
450 	node->data = get_image_page(gfp_mask, safe_needed);
451 	if (!node->data)
452 		return NULL;
453 
454 	list_add_tail(&node->list, list);
455 
456 	return node;
457 }
458 
459 /**
460  * add_rtree_block - Add a new leave node to the radix tree.
461  *
462  * The leave nodes need to be allocated in order to keep the leaves
463  * linked list in order. This is guaranteed by the zone->blocks
464  * counter.
465  */
add_rtree_block(struct mem_zone_bm_rtree * zone,gfp_t gfp_mask,int safe_needed,struct chain_allocator * ca)466 static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
467 			   int safe_needed, struct chain_allocator *ca)
468 {
469 	struct rtree_node *node, *block, **dst;
470 	unsigned int levels_needed, block_nr;
471 	int i;
472 
473 	block_nr = zone->blocks;
474 	levels_needed = 0;
475 
476 	/* How many levels do we need for this block nr? */
477 	while (block_nr) {
478 		levels_needed += 1;
479 		block_nr >>= BM_RTREE_LEVEL_SHIFT;
480 	}
481 
482 	/* Make sure the rtree has enough levels */
483 	for (i = zone->levels; i < levels_needed; i++) {
484 		node = alloc_rtree_node(gfp_mask, safe_needed, ca,
485 					&zone->nodes);
486 		if (!node)
487 			return -ENOMEM;
488 
489 		node->data[0] = (unsigned long)zone->rtree;
490 		zone->rtree = node;
491 		zone->levels += 1;
492 	}
493 
494 	/* Allocate new block */
495 	block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
496 	if (!block)
497 		return -ENOMEM;
498 
499 	/* Now walk the rtree to insert the block */
500 	node = zone->rtree;
501 	dst = &zone->rtree;
502 	block_nr = zone->blocks;
503 	for (i = zone->levels; i > 0; i--) {
504 		int index;
505 
506 		if (!node) {
507 			node = alloc_rtree_node(gfp_mask, safe_needed, ca,
508 						&zone->nodes);
509 			if (!node)
510 				return -ENOMEM;
511 			*dst = node;
512 		}
513 
514 		index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
515 		index &= BM_RTREE_LEVEL_MASK;
516 		dst = (struct rtree_node **)&((*dst)->data[index]);
517 		node = *dst;
518 	}
519 
520 	zone->blocks += 1;
521 	*dst = block;
522 
523 	return 0;
524 }
525 
526 static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
527 			       int clear_nosave_free);
528 
529 /**
530  * create_zone_bm_rtree - Create a radix tree for one zone.
531  *
532  * Allocated the mem_zone_bm_rtree structure and initializes it.
533  * This function also allocated and builds the radix tree for the
534  * zone.
535  */
create_zone_bm_rtree(gfp_t gfp_mask,int safe_needed,struct chain_allocator * ca,unsigned long start,unsigned long end)536 static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
537 						      int safe_needed,
538 						      struct chain_allocator *ca,
539 						      unsigned long start,
540 						      unsigned long end)
541 {
542 	struct mem_zone_bm_rtree *zone;
543 	unsigned int i, nr_blocks;
544 	unsigned long pages;
545 
546 	pages = end - start;
547 	zone  = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
548 	if (!zone)
549 		return NULL;
550 
551 	INIT_LIST_HEAD(&zone->nodes);
552 	INIT_LIST_HEAD(&zone->leaves);
553 	zone->start_pfn = start;
554 	zone->end_pfn = end;
555 	nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
556 
557 	for (i = 0; i < nr_blocks; i++) {
558 		if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
559 			free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
560 			return NULL;
561 		}
562 	}
563 
564 	return zone;
565 }
566 
567 /**
568  * free_zone_bm_rtree - Free the memory of the radix tree.
569  *
570  * Free all node pages of the radix tree. The mem_zone_bm_rtree
571  * structure itself is not freed here nor are the rtree_node
572  * structs.
573  */
free_zone_bm_rtree(struct mem_zone_bm_rtree * zone,int clear_nosave_free)574 static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
575 			       int clear_nosave_free)
576 {
577 	struct rtree_node *node;
578 
579 	list_for_each_entry(node, &zone->nodes, list)
580 		free_image_page(node->data, clear_nosave_free);
581 
582 	list_for_each_entry(node, &zone->leaves, list)
583 		free_image_page(node->data, clear_nosave_free);
584 }
585 
memory_bm_position_reset(struct memory_bitmap * bm)586 static void memory_bm_position_reset(struct memory_bitmap *bm)
587 {
588 	bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
589 				  list);
590 	bm->cur.node = list_entry(bm->cur.zone->leaves.next,
591 				  struct rtree_node, list);
592 	bm->cur.node_pfn = 0;
593 	bm->cur.cur_pfn = BM_END_OF_MAP;
594 	bm->cur.node_bit = 0;
595 }
596 
597 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
598 
599 struct mem_extent {
600 	struct list_head hook;
601 	unsigned long start;
602 	unsigned long end;
603 };
604 
605 /**
606  * free_mem_extents - Free a list of memory extents.
607  * @list: List of extents to free.
608  */
free_mem_extents(struct list_head * list)609 static void free_mem_extents(struct list_head *list)
610 {
611 	struct mem_extent *ext, *aux;
612 
613 	list_for_each_entry_safe(ext, aux, list, hook) {
614 		list_del(&ext->hook);
615 		kfree(ext);
616 	}
617 }
618 
619 /**
620  * create_mem_extents - Create a list of memory extents.
621  * @list: List to put the extents into.
622  * @gfp_mask: Mask to use for memory allocations.
623  *
624  * The extents represent contiguous ranges of PFNs.
625  */
create_mem_extents(struct list_head * list,gfp_t gfp_mask)626 static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
627 {
628 	struct zone *zone;
629 
630 	INIT_LIST_HEAD(list);
631 
632 	for_each_populated_zone(zone) {
633 		unsigned long zone_start, zone_end;
634 		struct mem_extent *ext, *cur, *aux;
635 
636 		zone_start = zone->zone_start_pfn;
637 		zone_end = zone_end_pfn(zone);
638 
639 		list_for_each_entry(ext, list, hook)
640 			if (zone_start <= ext->end)
641 				break;
642 
643 		if (&ext->hook == list || zone_end < ext->start) {
644 			/* New extent is necessary */
645 			struct mem_extent *new_ext;
646 
647 			new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
648 			if (!new_ext) {
649 				free_mem_extents(list);
650 				return -ENOMEM;
651 			}
652 			new_ext->start = zone_start;
653 			new_ext->end = zone_end;
654 			list_add_tail(&new_ext->hook, &ext->hook);
655 			continue;
656 		}
657 
658 		/* Merge this zone's range of PFNs with the existing one */
659 		if (zone_start < ext->start)
660 			ext->start = zone_start;
661 		if (zone_end > ext->end)
662 			ext->end = zone_end;
663 
664 		/* More merging may be possible */
665 		cur = ext;
666 		list_for_each_entry_safe_continue(cur, aux, list, hook) {
667 			if (zone_end < cur->start)
668 				break;
669 			if (zone_end < cur->end)
670 				ext->end = cur->end;
671 			list_del(&cur->hook);
672 			kfree(cur);
673 		}
674 	}
675 
676 	return 0;
677 }
678 
679 /**
680  * memory_bm_create - Allocate memory for a memory bitmap.
681  */
memory_bm_create(struct memory_bitmap * bm,gfp_t gfp_mask,int safe_needed)682 static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
683 			    int safe_needed)
684 {
685 	struct chain_allocator ca;
686 	struct list_head mem_extents;
687 	struct mem_extent *ext;
688 	int error;
689 
690 	chain_init(&ca, gfp_mask, safe_needed);
691 	INIT_LIST_HEAD(&bm->zones);
692 
693 	error = create_mem_extents(&mem_extents, gfp_mask);
694 	if (error)
695 		return error;
696 
697 	list_for_each_entry(ext, &mem_extents, hook) {
698 		struct mem_zone_bm_rtree *zone;
699 
700 		zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
701 					    ext->start, ext->end);
702 		if (!zone) {
703 			error = -ENOMEM;
704 			goto Error;
705 		}
706 		list_add_tail(&zone->list, &bm->zones);
707 	}
708 
709 	bm->p_list = ca.chain;
710 	memory_bm_position_reset(bm);
711  Exit:
712 	free_mem_extents(&mem_extents);
713 	return error;
714 
715  Error:
716 	bm->p_list = ca.chain;
717 	memory_bm_free(bm, PG_UNSAFE_CLEAR);
718 	goto Exit;
719 }
720 
721 /**
722  * memory_bm_free - Free memory occupied by the memory bitmap.
723  * @bm: Memory bitmap.
724  */
memory_bm_free(struct memory_bitmap * bm,int clear_nosave_free)725 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
726 {
727 	struct mem_zone_bm_rtree *zone;
728 
729 	list_for_each_entry(zone, &bm->zones, list)
730 		free_zone_bm_rtree(zone, clear_nosave_free);
731 
732 	free_list_of_pages(bm->p_list, clear_nosave_free);
733 
734 	INIT_LIST_HEAD(&bm->zones);
735 }
736 
737 /**
738  * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
739  *
740  * Find the bit in memory bitmap @bm that corresponds to the given PFN.
741  * The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
742  *
743  * Walk the radix tree to find the page containing the bit that represents @pfn
744  * and return the position of the bit in @addr and @bit_nr.
745  */
memory_bm_find_bit(struct memory_bitmap * bm,unsigned long pfn,void ** addr,unsigned int * bit_nr)746 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
747 			      void **addr, unsigned int *bit_nr)
748 {
749 	struct mem_zone_bm_rtree *curr, *zone;
750 	struct rtree_node *node;
751 	int i, block_nr;
752 
753 	zone = bm->cur.zone;
754 
755 	if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
756 		goto zone_found;
757 
758 	zone = NULL;
759 
760 	/* Find the right zone */
761 	list_for_each_entry(curr, &bm->zones, list) {
762 		if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
763 			zone = curr;
764 			break;
765 		}
766 	}
767 
768 	if (!zone)
769 		return -EFAULT;
770 
771 zone_found:
772 	/*
773 	 * We have found the zone. Now walk the radix tree to find the leaf node
774 	 * for our PFN.
775 	 */
776 
777 	/*
778 	 * If the zone we wish to scan is the current zone and the
779 	 * pfn falls into the current node then we do not need to walk
780 	 * the tree.
781 	 */
782 	node = bm->cur.node;
783 	if (zone == bm->cur.zone &&
784 	    ((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
785 		goto node_found;
786 
787 	node      = zone->rtree;
788 	block_nr  = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
789 
790 	for (i = zone->levels; i > 0; i--) {
791 		int index;
792 
793 		index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
794 		index &= BM_RTREE_LEVEL_MASK;
795 		BUG_ON(node->data[index] == 0);
796 		node = (struct rtree_node *)node->data[index];
797 	}
798 
799 node_found:
800 	/* Update last position */
801 	bm->cur.zone = zone;
802 	bm->cur.node = node;
803 	bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
804 	bm->cur.cur_pfn = pfn;
805 
806 	/* Set return values */
807 	*addr = node->data;
808 	*bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
809 
810 	return 0;
811 }
812 
memory_bm_set_bit(struct memory_bitmap * bm,unsigned long pfn)813 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
814 {
815 	void *addr;
816 	unsigned int bit;
817 	int error;
818 
819 	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
820 	BUG_ON(error);
821 	set_bit(bit, addr);
822 }
823 
mem_bm_set_bit_check(struct memory_bitmap * bm,unsigned long pfn)824 static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
825 {
826 	void *addr;
827 	unsigned int bit;
828 	int error;
829 
830 	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
831 	if (!error)
832 		set_bit(bit, addr);
833 
834 	return error;
835 }
836 
memory_bm_clear_bit(struct memory_bitmap * bm,unsigned long pfn)837 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
838 {
839 	void *addr;
840 	unsigned int bit;
841 	int error;
842 
843 	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
844 	BUG_ON(error);
845 	clear_bit(bit, addr);
846 }
847 
memory_bm_clear_current(struct memory_bitmap * bm)848 static void memory_bm_clear_current(struct memory_bitmap *bm)
849 {
850 	int bit;
851 
852 	bit = max(bm->cur.node_bit - 1, 0);
853 	clear_bit(bit, bm->cur.node->data);
854 }
855 
memory_bm_get_current(struct memory_bitmap * bm)856 static unsigned long memory_bm_get_current(struct memory_bitmap *bm)
857 {
858 	return bm->cur.cur_pfn;
859 }
860 
memory_bm_test_bit(struct memory_bitmap * bm,unsigned long pfn)861 static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
862 {
863 	void *addr;
864 	unsigned int bit;
865 	int error;
866 
867 	error = memory_bm_find_bit(bm, pfn, &addr, &bit);
868 	BUG_ON(error);
869 	return test_bit(bit, addr);
870 }
871 
memory_bm_pfn_present(struct memory_bitmap * bm,unsigned long pfn)872 static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
873 {
874 	void *addr;
875 	unsigned int bit;
876 
877 	return !memory_bm_find_bit(bm, pfn, &addr, &bit);
878 }
879 
880 /*
881  * rtree_next_node - Jump to the next leaf node.
882  *
883  * Set the position to the beginning of the next node in the
884  * memory bitmap. This is either the next node in the current
885  * zone's radix tree or the first node in the radix tree of the
886  * next zone.
887  *
888  * Return true if there is a next node, false otherwise.
889  */
rtree_next_node(struct memory_bitmap * bm)890 static bool rtree_next_node(struct memory_bitmap *bm)
891 {
892 	if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) {
893 		bm->cur.node = list_entry(bm->cur.node->list.next,
894 					  struct rtree_node, list);
895 		bm->cur.node_pfn += BM_BITS_PER_BLOCK;
896 		bm->cur.node_bit  = 0;
897 		touch_softlockup_watchdog();
898 		return true;
899 	}
900 
901 	/* No more nodes, goto next zone */
902 	if (!list_is_last(&bm->cur.zone->list, &bm->zones)) {
903 		bm->cur.zone = list_entry(bm->cur.zone->list.next,
904 				  struct mem_zone_bm_rtree, list);
905 		bm->cur.node = list_entry(bm->cur.zone->leaves.next,
906 					  struct rtree_node, list);
907 		bm->cur.node_pfn = 0;
908 		bm->cur.node_bit = 0;
909 		return true;
910 	}
911 
912 	/* No more zones */
913 	return false;
914 }
915 
916 /**
917  * memory_bm_next_pfn - Find the next set bit in a memory bitmap.
918  * @bm: Memory bitmap.
919  *
920  * Starting from the last returned position this function searches for the next
921  * set bit in @bm and returns the PFN represented by it.  If no more bits are
922  * set, BM_END_OF_MAP is returned.
923  *
924  * It is required to run memory_bm_position_reset() before the first call to
925  * this function for the given memory bitmap.
926  */
memory_bm_next_pfn(struct memory_bitmap * bm)927 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
928 {
929 	unsigned long bits, pfn, pages;
930 	int bit;
931 
932 	do {
933 		pages	  = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
934 		bits      = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
935 		bit	  = find_next_bit(bm->cur.node->data, bits,
936 					  bm->cur.node_bit);
937 		if (bit < bits) {
938 			pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
939 			bm->cur.node_bit = bit + 1;
940 			bm->cur.cur_pfn = pfn;
941 			return pfn;
942 		}
943 	} while (rtree_next_node(bm));
944 
945 	bm->cur.cur_pfn = BM_END_OF_MAP;
946 	return BM_END_OF_MAP;
947 }
948 
949 /*
950  * This structure represents a range of page frames the contents of which
951  * should not be saved during hibernation.
952  */
953 struct nosave_region {
954 	struct list_head list;
955 	unsigned long start_pfn;
956 	unsigned long end_pfn;
957 };
958 
959 static LIST_HEAD(nosave_regions);
960 
recycle_zone_bm_rtree(struct mem_zone_bm_rtree * zone)961 static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone)
962 {
963 	struct rtree_node *node;
964 
965 	list_for_each_entry(node, &zone->nodes, list)
966 		recycle_safe_page(node->data);
967 
968 	list_for_each_entry(node, &zone->leaves, list)
969 		recycle_safe_page(node->data);
970 }
971 
memory_bm_recycle(struct memory_bitmap * bm)972 static void memory_bm_recycle(struct memory_bitmap *bm)
973 {
974 	struct mem_zone_bm_rtree *zone;
975 	struct linked_page *p_list;
976 
977 	list_for_each_entry(zone, &bm->zones, list)
978 		recycle_zone_bm_rtree(zone);
979 
980 	p_list = bm->p_list;
981 	while (p_list) {
982 		struct linked_page *lp = p_list;
983 
984 		p_list = lp->next;
985 		recycle_safe_page(lp);
986 	}
987 }
988 
989 /**
990  * register_nosave_region - Register a region of unsaveable memory.
991  *
992  * Register a range of page frames the contents of which should not be saved
993  * during hibernation (to be used in the early initialization code).
994  */
register_nosave_region(unsigned long start_pfn,unsigned long end_pfn)995 void __init register_nosave_region(unsigned long start_pfn, unsigned long end_pfn)
996 {
997 	struct nosave_region *region;
998 
999 	if (start_pfn >= end_pfn)
1000 		return;
1001 
1002 	if (!list_empty(&nosave_regions)) {
1003 		/* Try to extend the previous region (they should be sorted) */
1004 		region = list_entry(nosave_regions.prev,
1005 					struct nosave_region, list);
1006 		if (region->end_pfn == start_pfn) {
1007 			region->end_pfn = end_pfn;
1008 			goto Report;
1009 		}
1010 	}
1011 	/* This allocation cannot fail */
1012 	region = memblock_alloc(sizeof(struct nosave_region),
1013 				SMP_CACHE_BYTES);
1014 	if (!region)
1015 		panic("%s: Failed to allocate %zu bytes\n", __func__,
1016 		      sizeof(struct nosave_region));
1017 	region->start_pfn = start_pfn;
1018 	region->end_pfn = end_pfn;
1019 	list_add_tail(&region->list, &nosave_regions);
1020  Report:
1021 	pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n",
1022 		(unsigned long long) start_pfn << PAGE_SHIFT,
1023 		((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
1024 }
1025 
1026 /*
1027  * Set bits in this map correspond to the page frames the contents of which
1028  * should not be saved during the suspend.
1029  */
1030 static struct memory_bitmap *forbidden_pages_map;
1031 
1032 /* Set bits in this map correspond to free page frames. */
1033 static struct memory_bitmap *free_pages_map;
1034 
1035 /*
1036  * Each page frame allocated for creating the image is marked by setting the
1037  * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
1038  */
1039 
swsusp_set_page_free(struct page * page)1040 void swsusp_set_page_free(struct page *page)
1041 {
1042 	if (free_pages_map)
1043 		memory_bm_set_bit(free_pages_map, page_to_pfn(page));
1044 }
1045 
swsusp_page_is_free(struct page * page)1046 static int swsusp_page_is_free(struct page *page)
1047 {
1048 	return free_pages_map ?
1049 		memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
1050 }
1051 
swsusp_unset_page_free(struct page * page)1052 void swsusp_unset_page_free(struct page *page)
1053 {
1054 	if (free_pages_map)
1055 		memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
1056 }
1057 
swsusp_set_page_forbidden(struct page * page)1058 static void swsusp_set_page_forbidden(struct page *page)
1059 {
1060 	if (forbidden_pages_map)
1061 		memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
1062 }
1063 
swsusp_page_is_forbidden(struct page * page)1064 int swsusp_page_is_forbidden(struct page *page)
1065 {
1066 	return forbidden_pages_map ?
1067 		memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
1068 }
1069 
swsusp_unset_page_forbidden(struct page * page)1070 static void swsusp_unset_page_forbidden(struct page *page)
1071 {
1072 	if (forbidden_pages_map)
1073 		memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
1074 }
1075 
1076 /**
1077  * mark_nosave_pages - Mark pages that should not be saved.
1078  * @bm: Memory bitmap.
1079  *
1080  * Set the bits in @bm that correspond to the page frames the contents of which
1081  * should not be saved.
1082  */
mark_nosave_pages(struct memory_bitmap * bm)1083 static void mark_nosave_pages(struct memory_bitmap *bm)
1084 {
1085 	struct nosave_region *region;
1086 
1087 	if (list_empty(&nosave_regions))
1088 		return;
1089 
1090 	list_for_each_entry(region, &nosave_regions, list) {
1091 		unsigned long pfn;
1092 
1093 		pr_debug("Marking nosave pages: [mem %#010llx-%#010llx]\n",
1094 			 (unsigned long long) region->start_pfn << PAGE_SHIFT,
1095 			 ((unsigned long long) region->end_pfn << PAGE_SHIFT)
1096 				- 1);
1097 
1098 		for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
1099 			if (pfn_valid(pfn)) {
1100 				/*
1101 				 * It is safe to ignore the result of
1102 				 * mem_bm_set_bit_check() here, since we won't
1103 				 * touch the PFNs for which the error is
1104 				 * returned anyway.
1105 				 */
1106 				mem_bm_set_bit_check(bm, pfn);
1107 			}
1108 	}
1109 }
1110 
1111 /**
1112  * create_basic_memory_bitmaps - Create bitmaps to hold basic page information.
1113  *
1114  * Create bitmaps needed for marking page frames that should not be saved and
1115  * free page frames.  The forbidden_pages_map and free_pages_map pointers are
1116  * only modified if everything goes well, because we don't want the bits to be
1117  * touched before both bitmaps are set up.
1118  */
create_basic_memory_bitmaps(void)1119 int create_basic_memory_bitmaps(void)
1120 {
1121 	struct memory_bitmap *bm1, *bm2;
1122 	int error = 0;
1123 
1124 	if (forbidden_pages_map && free_pages_map)
1125 		return 0;
1126 	else
1127 		BUG_ON(forbidden_pages_map || free_pages_map);
1128 
1129 	bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
1130 	if (!bm1)
1131 		return -ENOMEM;
1132 
1133 	error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
1134 	if (error)
1135 		goto Free_first_object;
1136 
1137 	bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
1138 	if (!bm2)
1139 		goto Free_first_bitmap;
1140 
1141 	error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
1142 	if (error)
1143 		goto Free_second_object;
1144 
1145 	forbidden_pages_map = bm1;
1146 	free_pages_map = bm2;
1147 	mark_nosave_pages(forbidden_pages_map);
1148 
1149 	pr_debug("Basic memory bitmaps created\n");
1150 
1151 	return 0;
1152 
1153  Free_second_object:
1154 	kfree(bm2);
1155  Free_first_bitmap:
1156 	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
1157  Free_first_object:
1158 	kfree(bm1);
1159 	return -ENOMEM;
1160 }
1161 
1162 /**
1163  * free_basic_memory_bitmaps - Free memory bitmaps holding basic information.
1164  *
1165  * Free memory bitmaps allocated by create_basic_memory_bitmaps().  The
1166  * auxiliary pointers are necessary so that the bitmaps themselves are not
1167  * referred to while they are being freed.
1168  */
free_basic_memory_bitmaps(void)1169 void free_basic_memory_bitmaps(void)
1170 {
1171 	struct memory_bitmap *bm1, *bm2;
1172 
1173 	if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
1174 		return;
1175 
1176 	bm1 = forbidden_pages_map;
1177 	bm2 = free_pages_map;
1178 	forbidden_pages_map = NULL;
1179 	free_pages_map = NULL;
1180 	memory_bm_free(bm1, PG_UNSAFE_CLEAR);
1181 	kfree(bm1);
1182 	memory_bm_free(bm2, PG_UNSAFE_CLEAR);
1183 	kfree(bm2);
1184 
1185 	pr_debug("Basic memory bitmaps freed\n");
1186 }
1187 
clear_or_poison_free_page(struct page * page)1188 static void clear_or_poison_free_page(struct page *page)
1189 {
1190 	if (page_poisoning_enabled_static())
1191 		__kernel_poison_pages(page, 1);
1192 	else if (want_init_on_free())
1193 		clear_highpage(page);
1194 }
1195 
clear_or_poison_free_pages(void)1196 void clear_or_poison_free_pages(void)
1197 {
1198 	struct memory_bitmap *bm = free_pages_map;
1199 	unsigned long pfn;
1200 
1201 	if (WARN_ON(!(free_pages_map)))
1202 		return;
1203 
1204 	if (page_poisoning_enabled() || want_init_on_free()) {
1205 		memory_bm_position_reset(bm);
1206 		pfn = memory_bm_next_pfn(bm);
1207 		while (pfn != BM_END_OF_MAP) {
1208 			if (pfn_valid(pfn))
1209 				clear_or_poison_free_page(pfn_to_page(pfn));
1210 
1211 			pfn = memory_bm_next_pfn(bm);
1212 		}
1213 		memory_bm_position_reset(bm);
1214 		pr_info("free pages cleared after restore\n");
1215 	}
1216 }
1217 
1218 /**
1219  * snapshot_additional_pages - Estimate the number of extra pages needed.
1220  * @zone: Memory zone to carry out the computation for.
1221  *
1222  * Estimate the number of additional pages needed for setting up a hibernation
1223  * image data structures for @zone (usually, the returned value is greater than
1224  * the exact number).
1225  */
snapshot_additional_pages(struct zone * zone)1226 unsigned int snapshot_additional_pages(struct zone *zone)
1227 {
1228 	unsigned int rtree, nodes;
1229 
1230 	rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
1231 	rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
1232 			      LINKED_PAGE_DATA_SIZE);
1233 	while (nodes > 1) {
1234 		nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
1235 		rtree += nodes;
1236 	}
1237 
1238 	return 2 * rtree;
1239 }
1240 
1241 /*
1242  * Touch the watchdog for every WD_PAGE_COUNT pages.
1243  */
1244 #define WD_PAGE_COUNT	(128*1024)
1245 
mark_free_pages(struct zone * zone)1246 static void mark_free_pages(struct zone *zone)
1247 {
1248 	unsigned long pfn, max_zone_pfn, page_count = WD_PAGE_COUNT;
1249 	unsigned long flags;
1250 	unsigned int order, t;
1251 	struct page *page;
1252 
1253 	if (zone_is_empty(zone))
1254 		return;
1255 
1256 	spin_lock_irqsave(&zone->lock, flags);
1257 
1258 	max_zone_pfn = zone_end_pfn(zone);
1259 	for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1260 		if (pfn_valid(pfn)) {
1261 			page = pfn_to_page(pfn);
1262 
1263 			if (!--page_count) {
1264 				touch_nmi_watchdog();
1265 				page_count = WD_PAGE_COUNT;
1266 			}
1267 
1268 			if (page_zone(page) != zone)
1269 				continue;
1270 
1271 			if (!swsusp_page_is_forbidden(page))
1272 				swsusp_unset_page_free(page);
1273 		}
1274 
1275 	for_each_migratetype_order(order, t) {
1276 		list_for_each_entry(page,
1277 				&zone->free_area[order].free_list[t], buddy_list) {
1278 			unsigned long i;
1279 
1280 			pfn = page_to_pfn(page);
1281 			for (i = 0; i < (1UL << order); i++) {
1282 				if (!--page_count) {
1283 					touch_nmi_watchdog();
1284 					page_count = WD_PAGE_COUNT;
1285 				}
1286 				swsusp_set_page_free(pfn_to_page(pfn + i));
1287 			}
1288 		}
1289 	}
1290 	spin_unlock_irqrestore(&zone->lock, flags);
1291 }
1292 
1293 #ifdef CONFIG_HIGHMEM
1294 /**
1295  * count_free_highmem_pages - Compute the total number of free highmem pages.
1296  *
1297  * The returned number is system-wide.
1298  */
count_free_highmem_pages(void)1299 static unsigned int count_free_highmem_pages(void)
1300 {
1301 	struct zone *zone;
1302 	unsigned int cnt = 0;
1303 
1304 	for_each_populated_zone(zone)
1305 		if (is_highmem(zone))
1306 			cnt += zone_page_state(zone, NR_FREE_PAGES);
1307 
1308 	return cnt;
1309 }
1310 
1311 /**
1312  * saveable_highmem_page - Check if a highmem page is saveable.
1313  *
1314  * Determine whether a highmem page should be included in a hibernation image.
1315  *
1316  * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
1317  * and it isn't part of a free chunk of pages.
1318  */
saveable_highmem_page(struct zone * zone,unsigned long pfn)1319 static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
1320 {
1321 	struct page *page;
1322 
1323 	if (!pfn_valid(pfn))
1324 		return NULL;
1325 
1326 	page = pfn_to_online_page(pfn);
1327 	if (!page || page_zone(page) != zone)
1328 		return NULL;
1329 
1330 	BUG_ON(!PageHighMem(page));
1331 
1332 	if (swsusp_page_is_forbidden(page) ||  swsusp_page_is_free(page))
1333 		return NULL;
1334 
1335 	if (PageReserved(page) || PageOffline(page))
1336 		return NULL;
1337 
1338 	if (page_is_guard(page))
1339 		return NULL;
1340 
1341 	return page;
1342 }
1343 
1344 /**
1345  * count_highmem_pages - Compute the total number of saveable highmem pages.
1346  */
count_highmem_pages(void)1347 static unsigned int count_highmem_pages(void)
1348 {
1349 	struct zone *zone;
1350 	unsigned int n = 0;
1351 
1352 	for_each_populated_zone(zone) {
1353 		unsigned long pfn, max_zone_pfn;
1354 
1355 		if (!is_highmem(zone))
1356 			continue;
1357 
1358 		mark_free_pages(zone);
1359 		max_zone_pfn = zone_end_pfn(zone);
1360 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1361 			if (saveable_highmem_page(zone, pfn))
1362 				n++;
1363 	}
1364 	return n;
1365 }
1366 #else
saveable_highmem_page(struct zone * z,unsigned long p)1367 static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
1368 {
1369 	return NULL;
1370 }
1371 #endif /* CONFIG_HIGHMEM */
1372 
1373 /**
1374  * saveable_page - Check if the given page is saveable.
1375  *
1376  * Determine whether a non-highmem page should be included in a hibernation
1377  * image.
1378  *
1379  * We should save the page if it isn't Nosave, and is not in the range
1380  * of pages statically defined as 'unsaveable', and it isn't part of
1381  * a free chunk of pages.
1382  */
saveable_page(struct zone * zone,unsigned long pfn)1383 static struct page *saveable_page(struct zone *zone, unsigned long pfn)
1384 {
1385 	struct page *page;
1386 
1387 	if (!pfn_valid(pfn))
1388 		return NULL;
1389 
1390 	page = pfn_to_online_page(pfn);
1391 	if (!page || page_zone(page) != zone)
1392 		return NULL;
1393 
1394 	BUG_ON(PageHighMem(page));
1395 
1396 	if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
1397 		return NULL;
1398 
1399 	if (PageOffline(page))
1400 		return NULL;
1401 
1402 	if (PageReserved(page)
1403 	    && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
1404 		return NULL;
1405 
1406 	if (page_is_guard(page))
1407 		return NULL;
1408 
1409 	return page;
1410 }
1411 
1412 /**
1413  * count_data_pages - Compute the total number of saveable non-highmem pages.
1414  */
count_data_pages(void)1415 static unsigned int count_data_pages(void)
1416 {
1417 	struct zone *zone;
1418 	unsigned long pfn, max_zone_pfn;
1419 	unsigned int n = 0;
1420 
1421 	for_each_populated_zone(zone) {
1422 		if (is_highmem(zone))
1423 			continue;
1424 
1425 		mark_free_pages(zone);
1426 		max_zone_pfn = zone_end_pfn(zone);
1427 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1428 			if (saveable_page(zone, pfn))
1429 				n++;
1430 	}
1431 	return n;
1432 }
1433 
1434 /*
1435  * This is needed, because copy_page and memcpy are not usable for copying
1436  * task structs. Returns true if the page was filled with only zeros,
1437  * otherwise false.
1438  */
do_copy_page(long * dst,long * src)1439 static inline bool do_copy_page(long *dst, long *src)
1440 {
1441 	long z = 0;
1442 	int n;
1443 
1444 	for (n = PAGE_SIZE / sizeof(long); n; n--) {
1445 		z |= *src;
1446 		*dst++ = *src++;
1447 	}
1448 	return !z;
1449 }
1450 
1451 /**
1452  * safe_copy_page - Copy a page in a safe way.
1453  *
1454  * Check if the page we are going to copy is marked as present in the kernel
1455  * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
1456  * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
1457  * always returns 'true'. Returns true if the page was entirely composed of
1458  * zeros, otherwise it will return false.
1459  */
safe_copy_page(void * dst,struct page * s_page)1460 static bool safe_copy_page(void *dst, struct page *s_page)
1461 {
1462 	bool zeros_only;
1463 
1464 	if (kernel_page_present(s_page)) {
1465 		zeros_only = do_copy_page(dst, page_address(s_page));
1466 	} else {
1467 		hibernate_map_page(s_page);
1468 		zeros_only = do_copy_page(dst, page_address(s_page));
1469 		hibernate_unmap_page(s_page);
1470 	}
1471 	return zeros_only;
1472 }
1473 
1474 #ifdef CONFIG_HIGHMEM
page_is_saveable(struct zone * zone,unsigned long pfn)1475 static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
1476 {
1477 	return is_highmem(zone) ?
1478 		saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
1479 }
1480 
copy_data_page(unsigned long dst_pfn,unsigned long src_pfn)1481 static bool copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1482 {
1483 	struct page *s_page, *d_page;
1484 	void *src, *dst;
1485 	bool zeros_only;
1486 
1487 	s_page = pfn_to_page(src_pfn);
1488 	d_page = pfn_to_page(dst_pfn);
1489 	if (PageHighMem(s_page)) {
1490 		src = kmap_atomic(s_page);
1491 		dst = kmap_atomic(d_page);
1492 		zeros_only = do_copy_page(dst, src);
1493 		kunmap_atomic(dst);
1494 		kunmap_atomic(src);
1495 	} else {
1496 		if (PageHighMem(d_page)) {
1497 			/*
1498 			 * The page pointed to by src may contain some kernel
1499 			 * data modified by kmap_atomic()
1500 			 */
1501 			zeros_only = safe_copy_page(buffer, s_page);
1502 			dst = kmap_atomic(d_page);
1503 			copy_page(dst, buffer);
1504 			kunmap_atomic(dst);
1505 		} else {
1506 			zeros_only = safe_copy_page(page_address(d_page), s_page);
1507 		}
1508 	}
1509 	return zeros_only;
1510 }
1511 #else
1512 #define page_is_saveable(zone, pfn)	saveable_page(zone, pfn)
1513 
copy_data_page(unsigned long dst_pfn,unsigned long src_pfn)1514 static inline int copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1515 {
1516 	return safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1517 				pfn_to_page(src_pfn));
1518 }
1519 #endif /* CONFIG_HIGHMEM */
1520 
1521 /*
1522  * Copy data pages will copy all pages into pages pulled from the copy_bm.
1523  * If a page was entirely filled with zeros it will be marked in the zero_bm.
1524  *
1525  * Returns the number of pages copied.
1526  */
copy_data_pages(struct memory_bitmap * copy_bm,struct memory_bitmap * orig_bm,struct memory_bitmap * zero_bm)1527 static unsigned long copy_data_pages(struct memory_bitmap *copy_bm,
1528 			    struct memory_bitmap *orig_bm,
1529 			    struct memory_bitmap *zero_bm)
1530 {
1531 	unsigned long copied_pages = 0;
1532 	struct zone *zone;
1533 	unsigned long pfn, copy_pfn;
1534 
1535 	for_each_populated_zone(zone) {
1536 		unsigned long max_zone_pfn;
1537 
1538 		mark_free_pages(zone);
1539 		max_zone_pfn = zone_end_pfn(zone);
1540 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1541 			if (page_is_saveable(zone, pfn))
1542 				memory_bm_set_bit(orig_bm, pfn);
1543 	}
1544 	memory_bm_position_reset(orig_bm);
1545 	memory_bm_position_reset(copy_bm);
1546 	copy_pfn = memory_bm_next_pfn(copy_bm);
1547 	for(;;) {
1548 		pfn = memory_bm_next_pfn(orig_bm);
1549 		if (unlikely(pfn == BM_END_OF_MAP))
1550 			break;
1551 		if (copy_data_page(copy_pfn, pfn)) {
1552 			memory_bm_set_bit(zero_bm, pfn);
1553 			/* Use this copy_pfn for a page that is not full of zeros */
1554 			continue;
1555 		}
1556 		copied_pages++;
1557 		copy_pfn = memory_bm_next_pfn(copy_bm);
1558 	}
1559 	return copied_pages;
1560 }
1561 
1562 /* Total number of image pages */
1563 static unsigned int nr_copy_pages;
1564 /* Number of pages needed for saving the original pfns of the image pages */
1565 static unsigned int nr_meta_pages;
1566 /* Number of zero pages */
1567 static unsigned int nr_zero_pages;
1568 
1569 /*
1570  * Numbers of normal and highmem page frames allocated for hibernation image
1571  * before suspending devices.
1572  */
1573 static unsigned int alloc_normal, alloc_highmem;
1574 /*
1575  * Memory bitmap used for marking saveable pages (during hibernation) or
1576  * hibernation image pages (during restore)
1577  */
1578 static struct memory_bitmap orig_bm;
1579 /*
1580  * Memory bitmap used during hibernation for marking allocated page frames that
1581  * will contain copies of saveable pages.  During restore it is initially used
1582  * for marking hibernation image pages, but then the set bits from it are
1583  * duplicated in @orig_bm and it is released.  On highmem systems it is next
1584  * used for marking "safe" highmem pages, but it has to be reinitialized for
1585  * this purpose.
1586  */
1587 static struct memory_bitmap copy_bm;
1588 
1589 /* Memory bitmap which tracks which saveable pages were zero filled. */
1590 static struct memory_bitmap zero_bm;
1591 
1592 /**
1593  * swsusp_free - Free pages allocated for hibernation image.
1594  *
1595  * Image pages are allocated before snapshot creation, so they need to be
1596  * released after resume.
1597  */
swsusp_free(void)1598 void swsusp_free(void)
1599 {
1600 	unsigned long fb_pfn, fr_pfn;
1601 
1602 	if (!forbidden_pages_map || !free_pages_map)
1603 		goto out;
1604 
1605 	memory_bm_position_reset(forbidden_pages_map);
1606 	memory_bm_position_reset(free_pages_map);
1607 
1608 loop:
1609 	fr_pfn = memory_bm_next_pfn(free_pages_map);
1610 	fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
1611 
1612 	/*
1613 	 * Find the next bit set in both bitmaps. This is guaranteed to
1614 	 * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
1615 	 */
1616 	do {
1617 		if (fb_pfn < fr_pfn)
1618 			fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
1619 		if (fr_pfn < fb_pfn)
1620 			fr_pfn = memory_bm_next_pfn(free_pages_map);
1621 	} while (fb_pfn != fr_pfn);
1622 
1623 	if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
1624 		struct page *page = pfn_to_page(fr_pfn);
1625 
1626 		memory_bm_clear_current(forbidden_pages_map);
1627 		memory_bm_clear_current(free_pages_map);
1628 		hibernate_restore_unprotect_page(page_address(page));
1629 		__free_page(page);
1630 		goto loop;
1631 	}
1632 
1633 out:
1634 	nr_copy_pages = 0;
1635 	nr_meta_pages = 0;
1636 	nr_zero_pages = 0;
1637 	restore_pblist = NULL;
1638 	buffer = NULL;
1639 	alloc_normal = 0;
1640 	alloc_highmem = 0;
1641 	hibernate_restore_protection_end();
1642 }
1643 
1644 /* Helper functions used for the shrinking of memory. */
1645 
1646 #define GFP_IMAGE	(GFP_KERNEL | __GFP_NOWARN)
1647 
1648 /**
1649  * preallocate_image_pages - Allocate a number of pages for hibernation image.
1650  * @nr_pages: Number of page frames to allocate.
1651  * @mask: GFP flags to use for the allocation.
1652  *
1653  * Return value: Number of page frames actually allocated
1654  */
preallocate_image_pages(unsigned long nr_pages,gfp_t mask)1655 static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1656 {
1657 	unsigned long nr_alloc = 0;
1658 
1659 	while (nr_pages > 0) {
1660 		struct page *page;
1661 
1662 		page = alloc_image_page(mask);
1663 		if (!page)
1664 			break;
1665 		memory_bm_set_bit(&copy_bm, page_to_pfn(page));
1666 		if (PageHighMem(page))
1667 			alloc_highmem++;
1668 		else
1669 			alloc_normal++;
1670 		nr_pages--;
1671 		nr_alloc++;
1672 	}
1673 
1674 	return nr_alloc;
1675 }
1676 
preallocate_image_memory(unsigned long nr_pages,unsigned long avail_normal)1677 static unsigned long preallocate_image_memory(unsigned long nr_pages,
1678 					      unsigned long avail_normal)
1679 {
1680 	unsigned long alloc;
1681 
1682 	if (avail_normal <= alloc_normal)
1683 		return 0;
1684 
1685 	alloc = avail_normal - alloc_normal;
1686 	if (nr_pages < alloc)
1687 		alloc = nr_pages;
1688 
1689 	return preallocate_image_pages(alloc, GFP_IMAGE);
1690 }
1691 
1692 #ifdef CONFIG_HIGHMEM
preallocate_image_highmem(unsigned long nr_pages)1693 static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1694 {
1695 	return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1696 }
1697 
1698 /**
1699  *  __fraction - Compute (an approximation of) x * (multiplier / base).
1700  */
__fraction(u64 x,u64 multiplier,u64 base)1701 static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1702 {
1703 	return div64_u64(x * multiplier, base);
1704 }
1705 
preallocate_highmem_fraction(unsigned long nr_pages,unsigned long highmem,unsigned long total)1706 static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1707 						  unsigned long highmem,
1708 						  unsigned long total)
1709 {
1710 	unsigned long alloc = __fraction(nr_pages, highmem, total);
1711 
1712 	return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1713 }
1714 #else /* CONFIG_HIGHMEM */
preallocate_image_highmem(unsigned long nr_pages)1715 static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1716 {
1717 	return 0;
1718 }
1719 
preallocate_highmem_fraction(unsigned long nr_pages,unsigned long highmem,unsigned long total)1720 static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1721 							 unsigned long highmem,
1722 							 unsigned long total)
1723 {
1724 	return 0;
1725 }
1726 #endif /* CONFIG_HIGHMEM */
1727 
1728 /**
1729  * free_unnecessary_pages - Release preallocated pages not needed for the image.
1730  */
free_unnecessary_pages(void)1731 static unsigned long free_unnecessary_pages(void)
1732 {
1733 	unsigned long save, to_free_normal, to_free_highmem, free;
1734 
1735 	save = count_data_pages();
1736 	if (alloc_normal >= save) {
1737 		to_free_normal = alloc_normal - save;
1738 		save = 0;
1739 	} else {
1740 		to_free_normal = 0;
1741 		save -= alloc_normal;
1742 	}
1743 	save += count_highmem_pages();
1744 	if (alloc_highmem >= save) {
1745 		to_free_highmem = alloc_highmem - save;
1746 	} else {
1747 		to_free_highmem = 0;
1748 		save -= alloc_highmem;
1749 		if (to_free_normal > save)
1750 			to_free_normal -= save;
1751 		else
1752 			to_free_normal = 0;
1753 	}
1754 	free = to_free_normal + to_free_highmem;
1755 
1756 	memory_bm_position_reset(&copy_bm);
1757 
1758 	while (to_free_normal > 0 || to_free_highmem > 0) {
1759 		unsigned long pfn = memory_bm_next_pfn(&copy_bm);
1760 		struct page *page = pfn_to_page(pfn);
1761 
1762 		if (PageHighMem(page)) {
1763 			if (!to_free_highmem)
1764 				continue;
1765 			to_free_highmem--;
1766 			alloc_highmem--;
1767 		} else {
1768 			if (!to_free_normal)
1769 				continue;
1770 			to_free_normal--;
1771 			alloc_normal--;
1772 		}
1773 		memory_bm_clear_bit(&copy_bm, pfn);
1774 		swsusp_unset_page_forbidden(page);
1775 		swsusp_unset_page_free(page);
1776 		__free_page(page);
1777 	}
1778 
1779 	return free;
1780 }
1781 
1782 /**
1783  * minimum_image_size - Estimate the minimum acceptable size of an image.
1784  * @saveable: Number of saveable pages in the system.
1785  *
1786  * We want to avoid attempting to free too much memory too hard, so estimate the
1787  * minimum acceptable size of a hibernation image to use as the lower limit for
1788  * preallocating memory.
1789  *
1790  * We assume that the minimum image size should be proportional to
1791  *
1792  * [number of saveable pages] - [number of pages that can be freed in theory]
1793  *
1794  * where the second term is the sum of (1) reclaimable slab pages, (2) active
1795  * and (3) inactive anonymous pages, (4) active and (5) inactive file pages.
1796  */
minimum_image_size(unsigned long saveable)1797 static unsigned long minimum_image_size(unsigned long saveable)
1798 {
1799 	unsigned long size;
1800 
1801 	size = global_node_page_state_pages(NR_SLAB_RECLAIMABLE_B)
1802 		+ global_node_page_state(NR_ACTIVE_ANON)
1803 		+ global_node_page_state(NR_INACTIVE_ANON)
1804 		+ global_node_page_state(NR_ACTIVE_FILE)
1805 		+ global_node_page_state(NR_INACTIVE_FILE);
1806 
1807 	return saveable <= size ? 0 : saveable - size;
1808 }
1809 
1810 /**
1811  * hibernate_preallocate_memory - Preallocate memory for hibernation image.
1812  *
1813  * To create a hibernation image it is necessary to make a copy of every page
1814  * frame in use.  We also need a number of page frames to be free during
1815  * hibernation for allocations made while saving the image and for device
1816  * drivers, in case they need to allocate memory from their hibernation
1817  * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
1818  * estimate) and reserved_size divided by PAGE_SIZE (which is tunable through
1819  * /sys/power/reserved_size, respectively).  To make this happen, we compute the
1820  * total number of available page frames and allocate at least
1821  *
1822  * ([page frames total] - PAGES_FOR_IO - [metadata pages]) / 2
1823  *  - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
1824  *
1825  * of them, which corresponds to the maximum size of a hibernation image.
1826  *
1827  * If image_size is set below the number following from the above formula,
1828  * the preallocation of memory is continued until the total number of saveable
1829  * pages in the system is below the requested image size or the minimum
1830  * acceptable image size returned by minimum_image_size(), whichever is greater.
1831  */
hibernate_preallocate_memory(void)1832 int hibernate_preallocate_memory(void)
1833 {
1834 	struct zone *zone;
1835 	unsigned long saveable, size, max_size, count, highmem, pages = 0;
1836 	unsigned long alloc, save_highmem, pages_highmem, avail_normal;
1837 	ktime_t start, stop;
1838 	int error;
1839 
1840 	pr_info("Preallocating image memory\n");
1841 	start = ktime_get();
1842 
1843 	error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
1844 	if (error) {
1845 		pr_err("Cannot allocate original bitmap\n");
1846 		goto err_out;
1847 	}
1848 
1849 	error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
1850 	if (error) {
1851 		pr_err("Cannot allocate copy bitmap\n");
1852 		goto err_out;
1853 	}
1854 
1855 	error = memory_bm_create(&zero_bm, GFP_IMAGE, PG_ANY);
1856 	if (error) {
1857 		pr_err("Cannot allocate zero bitmap\n");
1858 		goto err_out;
1859 	}
1860 
1861 	alloc_normal = 0;
1862 	alloc_highmem = 0;
1863 	nr_zero_pages = 0;
1864 
1865 	/* Count the number of saveable data pages. */
1866 	save_highmem = count_highmem_pages();
1867 	saveable = count_data_pages();
1868 
1869 	/*
1870 	 * Compute the total number of page frames we can use (count) and the
1871 	 * number of pages needed for image metadata (size).
1872 	 */
1873 	count = saveable;
1874 	saveable += save_highmem;
1875 	highmem = save_highmem;
1876 	size = 0;
1877 	for_each_populated_zone(zone) {
1878 		size += snapshot_additional_pages(zone);
1879 		if (is_highmem(zone))
1880 			highmem += zone_page_state(zone, NR_FREE_PAGES);
1881 		else
1882 			count += zone_page_state(zone, NR_FREE_PAGES);
1883 	}
1884 	avail_normal = count;
1885 	count += highmem;
1886 	count -= totalreserve_pages;
1887 
1888 	/* Compute the maximum number of saveable pages to leave in memory. */
1889 	max_size = (count - (size + PAGES_FOR_IO)) / 2
1890 			- 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
1891 	/* Compute the desired number of image pages specified by image_size. */
1892 	size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1893 	if (size > max_size)
1894 		size = max_size;
1895 	/*
1896 	 * If the desired number of image pages is at least as large as the
1897 	 * current number of saveable pages in memory, allocate page frames for
1898 	 * the image and we're done.
1899 	 */
1900 	if (size >= saveable) {
1901 		pages = preallocate_image_highmem(save_highmem);
1902 		pages += preallocate_image_memory(saveable - pages, avail_normal);
1903 		goto out;
1904 	}
1905 
1906 	/* Estimate the minimum size of the image. */
1907 	pages = minimum_image_size(saveable);
1908 	/*
1909 	 * To avoid excessive pressure on the normal zone, leave room in it to
1910 	 * accommodate an image of the minimum size (unless it's already too
1911 	 * small, in which case don't preallocate pages from it at all).
1912 	 */
1913 	if (avail_normal > pages)
1914 		avail_normal -= pages;
1915 	else
1916 		avail_normal = 0;
1917 	if (size < pages)
1918 		size = min_t(unsigned long, pages, max_size);
1919 
1920 	/*
1921 	 * Let the memory management subsystem know that we're going to need a
1922 	 * large number of page frames to allocate and make it free some memory.
1923 	 * NOTE: If this is not done, performance will be hurt badly in some
1924 	 * test cases.
1925 	 */
1926 	shrink_all_memory(saveable - size);
1927 
1928 	/*
1929 	 * The number of saveable pages in memory was too high, so apply some
1930 	 * pressure to decrease it.  First, make room for the largest possible
1931 	 * image and fail if that doesn't work.  Next, try to decrease the size
1932 	 * of the image as much as indicated by 'size' using allocations from
1933 	 * highmem and non-highmem zones separately.
1934 	 */
1935 	pages_highmem = preallocate_image_highmem(highmem / 2);
1936 	alloc = count - max_size;
1937 	if (alloc > pages_highmem)
1938 		alloc -= pages_highmem;
1939 	else
1940 		alloc = 0;
1941 	pages = preallocate_image_memory(alloc, avail_normal);
1942 	if (pages < alloc) {
1943 		/* We have exhausted non-highmem pages, try highmem. */
1944 		alloc -= pages;
1945 		pages += pages_highmem;
1946 		pages_highmem = preallocate_image_highmem(alloc);
1947 		if (pages_highmem < alloc) {
1948 			pr_err("Image allocation is %lu pages short\n",
1949 				alloc - pages_highmem);
1950 			goto err_out;
1951 		}
1952 		pages += pages_highmem;
1953 		/*
1954 		 * size is the desired number of saveable pages to leave in
1955 		 * memory, so try to preallocate (all memory - size) pages.
1956 		 */
1957 		alloc = (count - pages) - size;
1958 		pages += preallocate_image_highmem(alloc);
1959 	} else {
1960 		/*
1961 		 * There are approximately max_size saveable pages at this point
1962 		 * and we want to reduce this number down to size.
1963 		 */
1964 		alloc = max_size - size;
1965 		size = preallocate_highmem_fraction(alloc, highmem, count);
1966 		pages_highmem += size;
1967 		alloc -= size;
1968 		size = preallocate_image_memory(alloc, avail_normal);
1969 		pages_highmem += preallocate_image_highmem(alloc - size);
1970 		pages += pages_highmem + size;
1971 	}
1972 
1973 	/*
1974 	 * We only need as many page frames for the image as there are saveable
1975 	 * pages in memory, but we have allocated more.  Release the excessive
1976 	 * ones now.
1977 	 */
1978 	pages -= free_unnecessary_pages();
1979 
1980  out:
1981 	stop = ktime_get();
1982 	pr_info("Allocated %lu pages for snapshot\n", pages);
1983 	swsusp_show_speed(start, stop, pages, "Allocated");
1984 
1985 	return 0;
1986 
1987  err_out:
1988 	swsusp_free();
1989 	return -ENOMEM;
1990 }
1991 
1992 #ifdef CONFIG_HIGHMEM
1993 /**
1994  * count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
1995  *
1996  * Compute the number of non-highmem pages that will be necessary for creating
1997  * copies of highmem pages.
1998  */
count_pages_for_highmem(unsigned int nr_highmem)1999 static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
2000 {
2001 	unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
2002 
2003 	if (free_highmem >= nr_highmem)
2004 		nr_highmem = 0;
2005 	else
2006 		nr_highmem -= free_highmem;
2007 
2008 	return nr_highmem;
2009 }
2010 #else
count_pages_for_highmem(unsigned int nr_highmem)2011 static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
2012 #endif /* CONFIG_HIGHMEM */
2013 
2014 /**
2015  * enough_free_mem - Check if there is enough free memory for the image.
2016  */
enough_free_mem(unsigned int nr_pages,unsigned int nr_highmem)2017 static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
2018 {
2019 	struct zone *zone;
2020 	unsigned int free = alloc_normal;
2021 
2022 	for_each_populated_zone(zone)
2023 		if (!is_highmem(zone))
2024 			free += zone_page_state(zone, NR_FREE_PAGES);
2025 
2026 	nr_pages += count_pages_for_highmem(nr_highmem);
2027 	pr_debug("Normal pages needed: %u + %u, available pages: %u\n",
2028 		 nr_pages, PAGES_FOR_IO, free);
2029 
2030 	return free > nr_pages + PAGES_FOR_IO;
2031 }
2032 
2033 #ifdef CONFIG_HIGHMEM
2034 /**
2035  * get_highmem_buffer - Allocate a buffer for highmem pages.
2036  *
2037  * If there are some highmem pages in the hibernation image, we may need a
2038  * buffer to copy them and/or load their data.
2039  */
get_highmem_buffer(int safe_needed)2040 static inline int get_highmem_buffer(int safe_needed)
2041 {
2042 	buffer = get_image_page(GFP_ATOMIC, safe_needed);
2043 	return buffer ? 0 : -ENOMEM;
2044 }
2045 
2046 /**
2047  * alloc_highmem_pages - Allocate some highmem pages for the image.
2048  *
2049  * Try to allocate as many pages as needed, but if the number of free highmem
2050  * pages is less than that, allocate them all.
2051  */
alloc_highmem_pages(struct memory_bitmap * bm,unsigned int nr_highmem)2052 static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
2053 					       unsigned int nr_highmem)
2054 {
2055 	unsigned int to_alloc = count_free_highmem_pages();
2056 
2057 	if (to_alloc > nr_highmem)
2058 		to_alloc = nr_highmem;
2059 
2060 	nr_highmem -= to_alloc;
2061 	while (to_alloc-- > 0) {
2062 		struct page *page;
2063 
2064 		page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM);
2065 		memory_bm_set_bit(bm, page_to_pfn(page));
2066 	}
2067 	return nr_highmem;
2068 }
2069 #else
get_highmem_buffer(int safe_needed)2070 static inline int get_highmem_buffer(int safe_needed) { return 0; }
2071 
alloc_highmem_pages(struct memory_bitmap * bm,unsigned int n)2072 static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
2073 					       unsigned int n) { return 0; }
2074 #endif /* CONFIG_HIGHMEM */
2075 
2076 /**
2077  * swsusp_alloc - Allocate memory for hibernation image.
2078  *
2079  * We first try to allocate as many highmem pages as there are
2080  * saveable highmem pages in the system.  If that fails, we allocate
2081  * non-highmem pages for the copies of the remaining highmem ones.
2082  *
2083  * In this approach it is likely that the copies of highmem pages will
2084  * also be located in the high memory, because of the way in which
2085  * copy_data_pages() works.
2086  */
swsusp_alloc(struct memory_bitmap * copy_bm,unsigned int nr_pages,unsigned int nr_highmem)2087 static int swsusp_alloc(struct memory_bitmap *copy_bm,
2088 			unsigned int nr_pages, unsigned int nr_highmem)
2089 {
2090 	if (nr_highmem > 0) {
2091 		if (get_highmem_buffer(PG_ANY))
2092 			goto err_out;
2093 		if (nr_highmem > alloc_highmem) {
2094 			nr_highmem -= alloc_highmem;
2095 			nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
2096 		}
2097 	}
2098 	if (nr_pages > alloc_normal) {
2099 		nr_pages -= alloc_normal;
2100 		while (nr_pages-- > 0) {
2101 			struct page *page;
2102 
2103 			page = alloc_image_page(GFP_ATOMIC);
2104 			if (!page)
2105 				goto err_out;
2106 			memory_bm_set_bit(copy_bm, page_to_pfn(page));
2107 		}
2108 	}
2109 
2110 	return 0;
2111 
2112  err_out:
2113 	swsusp_free();
2114 	return -ENOMEM;
2115 }
2116 
swsusp_save(void)2117 asmlinkage __visible int swsusp_save(void)
2118 {
2119 	unsigned int nr_pages, nr_highmem;
2120 
2121 	pr_info("Creating image:\n");
2122 
2123 	drain_local_pages(NULL);
2124 	nr_pages = count_data_pages();
2125 	nr_highmem = count_highmem_pages();
2126 	pr_info("Need to copy %u pages\n", nr_pages + nr_highmem);
2127 
2128 	if (!enough_free_mem(nr_pages, nr_highmem)) {
2129 		pr_err("Not enough free memory\n");
2130 		return -ENOMEM;
2131 	}
2132 
2133 	if (swsusp_alloc(&copy_bm, nr_pages, nr_highmem)) {
2134 		pr_err("Memory allocation failed\n");
2135 		return -ENOMEM;
2136 	}
2137 
2138 	/*
2139 	 * During allocating of suspend pagedir, new cold pages may appear.
2140 	 * Kill them.
2141 	 */
2142 	drain_local_pages(NULL);
2143 	nr_copy_pages = copy_data_pages(&copy_bm, &orig_bm, &zero_bm);
2144 
2145 	/*
2146 	 * End of critical section. From now on, we can write to memory,
2147 	 * but we should not touch disk. This specially means we must _not_
2148 	 * touch swap space! Except we must write out our image of course.
2149 	 */
2150 	nr_pages += nr_highmem;
2151 	/* We don't actually copy the zero pages */
2152 	nr_zero_pages = nr_pages - nr_copy_pages;
2153 	nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
2154 
2155 	pr_info("Image created (%d pages copied, %d zero pages)\n", nr_copy_pages, nr_zero_pages);
2156 
2157 	return 0;
2158 }
2159 
2160 #ifndef CONFIG_ARCH_HIBERNATION_HEADER
init_header_complete(struct swsusp_info * info)2161 static int init_header_complete(struct swsusp_info *info)
2162 {
2163 	memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
2164 	info->version_code = LINUX_VERSION_CODE;
2165 	return 0;
2166 }
2167 
check_image_kernel(struct swsusp_info * info)2168 static const char *check_image_kernel(struct swsusp_info *info)
2169 {
2170 	if (info->version_code != LINUX_VERSION_CODE)
2171 		return "kernel version";
2172 	if (strcmp(info->uts.sysname,init_utsname()->sysname))
2173 		return "system type";
2174 	if (strcmp(info->uts.release,init_utsname()->release))
2175 		return "kernel release";
2176 	if (strcmp(info->uts.version,init_utsname()->version))
2177 		return "version";
2178 	if (strcmp(info->uts.machine,init_utsname()->machine))
2179 		return "machine";
2180 	return NULL;
2181 }
2182 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
2183 
snapshot_get_image_size(void)2184 unsigned long snapshot_get_image_size(void)
2185 {
2186 	return nr_copy_pages + nr_meta_pages + 1;
2187 }
2188 
init_header(struct swsusp_info * info)2189 static int init_header(struct swsusp_info *info)
2190 {
2191 	memset(info, 0, sizeof(struct swsusp_info));
2192 	info->num_physpages = get_num_physpages();
2193 	info->image_pages = nr_copy_pages;
2194 	info->pages = snapshot_get_image_size();
2195 	info->size = info->pages;
2196 	info->size <<= PAGE_SHIFT;
2197 	return init_header_complete(info);
2198 }
2199 
2200 #define ENCODED_PFN_ZERO_FLAG ((unsigned long)1 << (BITS_PER_LONG - 1))
2201 #define ENCODED_PFN_MASK (~ENCODED_PFN_ZERO_FLAG)
2202 
2203 /**
2204  * pack_pfns - Prepare PFNs for saving.
2205  * @bm: Memory bitmap.
2206  * @buf: Memory buffer to store the PFNs in.
2207  * @zero_bm: Memory bitmap containing PFNs of zero pages.
2208  *
2209  * PFNs corresponding to set bits in @bm are stored in the area of memory
2210  * pointed to by @buf (1 page at a time). Pages which were filled with only
2211  * zeros will have the highest bit set in the packed format to distinguish
2212  * them from PFNs which will be contained in the image file.
2213  */
pack_pfns(unsigned long * buf,struct memory_bitmap * bm,struct memory_bitmap * zero_bm)2214 static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm,
2215 		struct memory_bitmap *zero_bm)
2216 {
2217 	int j;
2218 
2219 	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2220 		buf[j] = memory_bm_next_pfn(bm);
2221 		if (unlikely(buf[j] == BM_END_OF_MAP))
2222 			break;
2223 		if (memory_bm_test_bit(zero_bm, buf[j]))
2224 			buf[j] |= ENCODED_PFN_ZERO_FLAG;
2225 	}
2226 }
2227 
2228 /**
2229  * snapshot_read_next - Get the address to read the next image page from.
2230  * @handle: Snapshot handle to be used for the reading.
2231  *
2232  * On the first call, @handle should point to a zeroed snapshot_handle
2233  * structure.  The structure gets populated then and a pointer to it should be
2234  * passed to this function every next time.
2235  *
2236  * On success, the function returns a positive number.  Then, the caller
2237  * is allowed to read up to the returned number of bytes from the memory
2238  * location computed by the data_of() macro.
2239  *
2240  * The function returns 0 to indicate the end of the data stream condition,
2241  * and negative numbers are returned on errors.  If that happens, the structure
2242  * pointed to by @handle is not updated and should not be used any more.
2243  */
snapshot_read_next(struct snapshot_handle * handle)2244 int snapshot_read_next(struct snapshot_handle *handle)
2245 {
2246 	if (handle->cur > nr_meta_pages + nr_copy_pages)
2247 		return 0;
2248 
2249 	if (!buffer) {
2250 		/* This makes the buffer be freed by swsusp_free() */
2251 		buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2252 		if (!buffer)
2253 			return -ENOMEM;
2254 	}
2255 	if (!handle->cur) {
2256 		int error;
2257 
2258 		error = init_header((struct swsusp_info *)buffer);
2259 		if (error)
2260 			return error;
2261 		handle->buffer = buffer;
2262 		memory_bm_position_reset(&orig_bm);
2263 		memory_bm_position_reset(&copy_bm);
2264 	} else if (handle->cur <= nr_meta_pages) {
2265 		clear_page(buffer);
2266 		pack_pfns(buffer, &orig_bm, &zero_bm);
2267 	} else {
2268 		struct page *page;
2269 
2270 		page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
2271 		if (PageHighMem(page)) {
2272 			/*
2273 			 * Highmem pages are copied to the buffer,
2274 			 * because we can't return with a kmapped
2275 			 * highmem page (we may not be called again).
2276 			 */
2277 			void *kaddr;
2278 
2279 			kaddr = kmap_atomic(page);
2280 			copy_page(buffer, kaddr);
2281 			kunmap_atomic(kaddr);
2282 			handle->buffer = buffer;
2283 		} else {
2284 			handle->buffer = page_address(page);
2285 		}
2286 	}
2287 	handle->cur++;
2288 	return PAGE_SIZE;
2289 }
2290 
duplicate_memory_bitmap(struct memory_bitmap * dst,struct memory_bitmap * src)2291 static void duplicate_memory_bitmap(struct memory_bitmap *dst,
2292 				    struct memory_bitmap *src)
2293 {
2294 	unsigned long pfn;
2295 
2296 	memory_bm_position_reset(src);
2297 	pfn = memory_bm_next_pfn(src);
2298 	while (pfn != BM_END_OF_MAP) {
2299 		memory_bm_set_bit(dst, pfn);
2300 		pfn = memory_bm_next_pfn(src);
2301 	}
2302 }
2303 
2304 /**
2305  * mark_unsafe_pages - Mark pages that were used before hibernation.
2306  *
2307  * Mark the pages that cannot be used for storing the image during restoration,
2308  * because they conflict with the pages that had been used before hibernation.
2309  */
mark_unsafe_pages(struct memory_bitmap * bm)2310 static void mark_unsafe_pages(struct memory_bitmap *bm)
2311 {
2312 	unsigned long pfn;
2313 
2314 	/* Clear the "free"/"unsafe" bit for all PFNs */
2315 	memory_bm_position_reset(free_pages_map);
2316 	pfn = memory_bm_next_pfn(free_pages_map);
2317 	while (pfn != BM_END_OF_MAP) {
2318 		memory_bm_clear_current(free_pages_map);
2319 		pfn = memory_bm_next_pfn(free_pages_map);
2320 	}
2321 
2322 	/* Mark pages that correspond to the "original" PFNs as "unsafe" */
2323 	duplicate_memory_bitmap(free_pages_map, bm);
2324 
2325 	allocated_unsafe_pages = 0;
2326 }
2327 
check_header(struct swsusp_info * info)2328 static int check_header(struct swsusp_info *info)
2329 {
2330 	const char *reason;
2331 
2332 	reason = check_image_kernel(info);
2333 	if (!reason && info->num_physpages != get_num_physpages())
2334 		reason = "memory size";
2335 	if (reason) {
2336 		pr_err("Image mismatch: %s\n", reason);
2337 		return -EPERM;
2338 	}
2339 	return 0;
2340 }
2341 
2342 /**
2343  * load_header - Check the image header and copy the data from it.
2344  */
load_header(struct swsusp_info * info)2345 static int load_header(struct swsusp_info *info)
2346 {
2347 	int error;
2348 
2349 	restore_pblist = NULL;
2350 	error = check_header(info);
2351 	if (!error) {
2352 		nr_copy_pages = info->image_pages;
2353 		nr_meta_pages = info->pages - info->image_pages - 1;
2354 	}
2355 	return error;
2356 }
2357 
2358 /**
2359  * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
2360  * @bm: Memory bitmap.
2361  * @buf: Area of memory containing the PFNs.
2362  * @zero_bm: Memory bitmap with the zero PFNs marked.
2363  *
2364  * For each element of the array pointed to by @buf (1 page at a time), set the
2365  * corresponding bit in @bm. If the page was originally populated with only
2366  * zeros then a corresponding bit will also be set in @zero_bm.
2367  */
unpack_orig_pfns(unsigned long * buf,struct memory_bitmap * bm,struct memory_bitmap * zero_bm)2368 static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm,
2369 		struct memory_bitmap *zero_bm)
2370 {
2371 	unsigned long decoded_pfn;
2372         bool zero;
2373 	int j;
2374 
2375 	for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2376 		if (unlikely(buf[j] == BM_END_OF_MAP))
2377 			break;
2378 
2379 		zero = !!(buf[j] & ENCODED_PFN_ZERO_FLAG);
2380 		decoded_pfn = buf[j] & ENCODED_PFN_MASK;
2381 		if (pfn_valid(decoded_pfn) && memory_bm_pfn_present(bm, decoded_pfn)) {
2382 			memory_bm_set_bit(bm, decoded_pfn);
2383 			if (zero) {
2384 				memory_bm_set_bit(zero_bm, decoded_pfn);
2385 				nr_zero_pages++;
2386 			}
2387 		} else {
2388 			if (!pfn_valid(decoded_pfn))
2389 				pr_err(FW_BUG "Memory map mismatch at 0x%llx after hibernation\n",
2390 				       (unsigned long long)PFN_PHYS(decoded_pfn));
2391 			return -EFAULT;
2392 		}
2393 	}
2394 
2395 	return 0;
2396 }
2397 
2398 #ifdef CONFIG_HIGHMEM
2399 /*
2400  * struct highmem_pbe is used for creating the list of highmem pages that
2401  * should be restored atomically during the resume from disk, because the page
2402  * frames they have occupied before the suspend are in use.
2403  */
2404 struct highmem_pbe {
2405 	struct page *copy_page;	/* data is here now */
2406 	struct page *orig_page;	/* data was here before the suspend */
2407 	struct highmem_pbe *next;
2408 };
2409 
2410 /*
2411  * List of highmem PBEs needed for restoring the highmem pages that were
2412  * allocated before the suspend and included in the suspend image, but have
2413  * also been allocated by the "resume" kernel, so their contents cannot be
2414  * written directly to their "original" page frames.
2415  */
2416 static struct highmem_pbe *highmem_pblist;
2417 
2418 /**
2419  * count_highmem_image_pages - Compute the number of highmem pages in the image.
2420  * @bm: Memory bitmap.
2421  *
2422  * The bits in @bm that correspond to image pages are assumed to be set.
2423  */
count_highmem_image_pages(struct memory_bitmap * bm)2424 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
2425 {
2426 	unsigned long pfn;
2427 	unsigned int cnt = 0;
2428 
2429 	memory_bm_position_reset(bm);
2430 	pfn = memory_bm_next_pfn(bm);
2431 	while (pfn != BM_END_OF_MAP) {
2432 		if (PageHighMem(pfn_to_page(pfn)))
2433 			cnt++;
2434 
2435 		pfn = memory_bm_next_pfn(bm);
2436 	}
2437 	return cnt;
2438 }
2439 
2440 static unsigned int safe_highmem_pages;
2441 
2442 static struct memory_bitmap *safe_highmem_bm;
2443 
2444 /**
2445  * prepare_highmem_image - Allocate memory for loading highmem data from image.
2446  * @bm: Pointer to an uninitialized memory bitmap structure.
2447  * @nr_highmem_p: Pointer to the number of highmem image pages.
2448  *
2449  * Try to allocate as many highmem pages as there are highmem image pages
2450  * (@nr_highmem_p points to the variable containing the number of highmem image
2451  * pages).  The pages that are "safe" (ie. will not be overwritten when the
2452  * hibernation image is restored entirely) have the corresponding bits set in
2453  * @bm (it must be uninitialized).
2454  *
2455  * NOTE: This function should not be called if there are no highmem image pages.
2456  */
prepare_highmem_image(struct memory_bitmap * bm,unsigned int * nr_highmem_p)2457 static int prepare_highmem_image(struct memory_bitmap *bm,
2458 				 unsigned int *nr_highmem_p)
2459 {
2460 	unsigned int to_alloc;
2461 
2462 	if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
2463 		return -ENOMEM;
2464 
2465 	if (get_highmem_buffer(PG_SAFE))
2466 		return -ENOMEM;
2467 
2468 	to_alloc = count_free_highmem_pages();
2469 	if (to_alloc > *nr_highmem_p)
2470 		to_alloc = *nr_highmem_p;
2471 	else
2472 		*nr_highmem_p = to_alloc;
2473 
2474 	safe_highmem_pages = 0;
2475 	while (to_alloc-- > 0) {
2476 		struct page *page;
2477 
2478 		page = alloc_page(__GFP_HIGHMEM);
2479 		if (!swsusp_page_is_free(page)) {
2480 			/* The page is "safe", set its bit the bitmap */
2481 			memory_bm_set_bit(bm, page_to_pfn(page));
2482 			safe_highmem_pages++;
2483 		}
2484 		/* Mark the page as allocated */
2485 		swsusp_set_page_forbidden(page);
2486 		swsusp_set_page_free(page);
2487 	}
2488 	memory_bm_position_reset(bm);
2489 	safe_highmem_bm = bm;
2490 	return 0;
2491 }
2492 
2493 static struct page *last_highmem_page;
2494 
2495 /**
2496  * get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
2497  *
2498  * For a given highmem image page get a buffer that suspend_write_next() should
2499  * return to its caller to write to.
2500  *
2501  * If the page is to be saved to its "original" page frame or a copy of
2502  * the page is to be made in the highmem, @buffer is returned.  Otherwise,
2503  * the copy of the page is to be made in normal memory, so the address of
2504  * the copy is returned.
2505  *
2506  * If @buffer is returned, the caller of suspend_write_next() will write
2507  * the page's contents to @buffer, so they will have to be copied to the
2508  * right location on the next call to suspend_write_next() and it is done
2509  * with the help of copy_last_highmem_page().  For this purpose, if
2510  * @buffer is returned, @last_highmem_page is set to the page to which
2511  * the data will have to be copied from @buffer.
2512  */
get_highmem_page_buffer(struct page * page,struct chain_allocator * ca)2513 static void *get_highmem_page_buffer(struct page *page,
2514 				     struct chain_allocator *ca)
2515 {
2516 	struct highmem_pbe *pbe;
2517 	void *kaddr;
2518 
2519 	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
2520 		/*
2521 		 * We have allocated the "original" page frame and we can
2522 		 * use it directly to store the loaded page.
2523 		 */
2524 		last_highmem_page = page;
2525 		return buffer;
2526 	}
2527 	/*
2528 	 * The "original" page frame has not been allocated and we have to
2529 	 * use a "safe" page frame to store the loaded page.
2530 	 */
2531 	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
2532 	if (!pbe) {
2533 		swsusp_free();
2534 		return ERR_PTR(-ENOMEM);
2535 	}
2536 	pbe->orig_page = page;
2537 	if (safe_highmem_pages > 0) {
2538 		struct page *tmp;
2539 
2540 		/* Copy of the page will be stored in high memory */
2541 		kaddr = buffer;
2542 		tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
2543 		safe_highmem_pages--;
2544 		last_highmem_page = tmp;
2545 		pbe->copy_page = tmp;
2546 	} else {
2547 		/* Copy of the page will be stored in normal memory */
2548 		kaddr = __get_safe_page(ca->gfp_mask);
2549 		if (!kaddr)
2550 			return ERR_PTR(-ENOMEM);
2551 		pbe->copy_page = virt_to_page(kaddr);
2552 	}
2553 	pbe->next = highmem_pblist;
2554 	highmem_pblist = pbe;
2555 	return kaddr;
2556 }
2557 
2558 /**
2559  * copy_last_highmem_page - Copy most the most recent highmem image page.
2560  *
2561  * Copy the contents of a highmem image from @buffer, where the caller of
2562  * snapshot_write_next() has stored them, to the right location represented by
2563  * @last_highmem_page .
2564  */
copy_last_highmem_page(void)2565 static void copy_last_highmem_page(void)
2566 {
2567 	if (last_highmem_page) {
2568 		void *dst;
2569 
2570 		dst = kmap_atomic(last_highmem_page);
2571 		copy_page(dst, buffer);
2572 		kunmap_atomic(dst);
2573 		last_highmem_page = NULL;
2574 	}
2575 }
2576 
last_highmem_page_copied(void)2577 static inline int last_highmem_page_copied(void)
2578 {
2579 	return !last_highmem_page;
2580 }
2581 
free_highmem_data(void)2582 static inline void free_highmem_data(void)
2583 {
2584 	if (safe_highmem_bm)
2585 		memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
2586 
2587 	if (buffer)
2588 		free_image_page(buffer, PG_UNSAFE_CLEAR);
2589 }
2590 #else
count_highmem_image_pages(struct memory_bitmap * bm)2591 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
2592 
prepare_highmem_image(struct memory_bitmap * bm,unsigned int * nr_highmem_p)2593 static inline int prepare_highmem_image(struct memory_bitmap *bm,
2594 					unsigned int *nr_highmem_p) { return 0; }
2595 
get_highmem_page_buffer(struct page * page,struct chain_allocator * ca)2596 static inline void *get_highmem_page_buffer(struct page *page,
2597 					    struct chain_allocator *ca)
2598 {
2599 	return ERR_PTR(-EINVAL);
2600 }
2601 
copy_last_highmem_page(void)2602 static inline void copy_last_highmem_page(void) {}
last_highmem_page_copied(void)2603 static inline int last_highmem_page_copied(void) { return 1; }
free_highmem_data(void)2604 static inline void free_highmem_data(void) {}
2605 #endif /* CONFIG_HIGHMEM */
2606 
2607 #define PBES_PER_LINKED_PAGE	(LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
2608 
2609 /**
2610  * prepare_image - Make room for loading hibernation image.
2611  * @new_bm: Uninitialized memory bitmap structure.
2612  * @bm: Memory bitmap with unsafe pages marked.
2613  * @zero_bm: Memory bitmap containing the zero pages.
2614  *
2615  * Use @bm to mark the pages that will be overwritten in the process of
2616  * restoring the system memory state from the suspend image ("unsafe" pages)
2617  * and allocate memory for the image.
2618  *
2619  * The idea is to allocate a new memory bitmap first and then allocate
2620  * as many pages as needed for image data, but without specifying what those
2621  * pages will be used for just yet.  Instead, we mark them all as allocated and
2622  * create a lists of "safe" pages to be used later.  On systems with high
2623  * memory a list of "safe" highmem pages is created too.
2624  *
2625  * Because it was not known which pages were unsafe when @zero_bm was created,
2626  * make a copy of it and recreate it within safe pages.
2627  */
prepare_image(struct memory_bitmap * new_bm,struct memory_bitmap * bm,struct memory_bitmap * zero_bm)2628 static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm,
2629 		struct memory_bitmap *zero_bm)
2630 {
2631 	unsigned int nr_pages, nr_highmem;
2632 	struct memory_bitmap tmp;
2633 	struct linked_page *lp;
2634 	int error;
2635 
2636 	/* If there is no highmem, the buffer will not be necessary */
2637 	free_image_page(buffer, PG_UNSAFE_CLEAR);
2638 	buffer = NULL;
2639 
2640 	nr_highmem = count_highmem_image_pages(bm);
2641 	mark_unsafe_pages(bm);
2642 
2643 	error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
2644 	if (error)
2645 		goto Free;
2646 
2647 	duplicate_memory_bitmap(new_bm, bm);
2648 	memory_bm_free(bm, PG_UNSAFE_KEEP);
2649 
2650 	/* Make a copy of zero_bm so it can be created in safe pages */
2651 	error = memory_bm_create(&tmp, GFP_ATOMIC, PG_SAFE);
2652 	if (error)
2653 		goto Free;
2654 
2655 	duplicate_memory_bitmap(&tmp, zero_bm);
2656 	memory_bm_free(zero_bm, PG_UNSAFE_KEEP);
2657 
2658 	/* Recreate zero_bm in safe pages */
2659 	error = memory_bm_create(zero_bm, GFP_ATOMIC, PG_SAFE);
2660 	if (error)
2661 		goto Free;
2662 
2663 	duplicate_memory_bitmap(zero_bm, &tmp);
2664 	memory_bm_free(&tmp, PG_UNSAFE_CLEAR);
2665 	/* At this point zero_bm is in safe pages and it can be used for restoring. */
2666 
2667 	if (nr_highmem > 0) {
2668 		error = prepare_highmem_image(bm, &nr_highmem);
2669 		if (error)
2670 			goto Free;
2671 	}
2672 	/*
2673 	 * Reserve some safe pages for potential later use.
2674 	 *
2675 	 * NOTE: This way we make sure there will be enough safe pages for the
2676 	 * chain_alloc() in get_buffer().  It is a bit wasteful, but
2677 	 * nr_copy_pages cannot be greater than 50% of the memory anyway.
2678 	 *
2679 	 * nr_copy_pages cannot be less than allocated_unsafe_pages too.
2680 	 */
2681 	nr_pages = (nr_zero_pages + nr_copy_pages) - nr_highmem - allocated_unsafe_pages;
2682 	nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
2683 	while (nr_pages > 0) {
2684 		lp = get_image_page(GFP_ATOMIC, PG_SAFE);
2685 		if (!lp) {
2686 			error = -ENOMEM;
2687 			goto Free;
2688 		}
2689 		lp->next = safe_pages_list;
2690 		safe_pages_list = lp;
2691 		nr_pages--;
2692 	}
2693 	/* Preallocate memory for the image */
2694 	nr_pages = (nr_zero_pages + nr_copy_pages) - nr_highmem - allocated_unsafe_pages;
2695 	while (nr_pages > 0) {
2696 		lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
2697 		if (!lp) {
2698 			error = -ENOMEM;
2699 			goto Free;
2700 		}
2701 		if (!swsusp_page_is_free(virt_to_page(lp))) {
2702 			/* The page is "safe", add it to the list */
2703 			lp->next = safe_pages_list;
2704 			safe_pages_list = lp;
2705 		}
2706 		/* Mark the page as allocated */
2707 		swsusp_set_page_forbidden(virt_to_page(lp));
2708 		swsusp_set_page_free(virt_to_page(lp));
2709 		nr_pages--;
2710 	}
2711 	return 0;
2712 
2713  Free:
2714 	swsusp_free();
2715 	return error;
2716 }
2717 
2718 /**
2719  * get_buffer - Get the address to store the next image data page.
2720  *
2721  * Get the address that snapshot_write_next() should return to its caller to
2722  * write to.
2723  */
get_buffer(struct memory_bitmap * bm,struct chain_allocator * ca)2724 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
2725 {
2726 	struct pbe *pbe;
2727 	struct page *page;
2728 	unsigned long pfn = memory_bm_next_pfn(bm);
2729 
2730 	if (pfn == BM_END_OF_MAP)
2731 		return ERR_PTR(-EFAULT);
2732 
2733 	page = pfn_to_page(pfn);
2734 	if (PageHighMem(page))
2735 		return get_highmem_page_buffer(page, ca);
2736 
2737 	if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2738 		/*
2739 		 * We have allocated the "original" page frame and we can
2740 		 * use it directly to store the loaded page.
2741 		 */
2742 		return page_address(page);
2743 
2744 	/*
2745 	 * The "original" page frame has not been allocated and we have to
2746 	 * use a "safe" page frame to store the loaded page.
2747 	 */
2748 	pbe = chain_alloc(ca, sizeof(struct pbe));
2749 	if (!pbe) {
2750 		swsusp_free();
2751 		return ERR_PTR(-ENOMEM);
2752 	}
2753 	pbe->orig_address = page_address(page);
2754 	pbe->address = __get_safe_page(ca->gfp_mask);
2755 	if (!pbe->address)
2756 		return ERR_PTR(-ENOMEM);
2757 	pbe->next = restore_pblist;
2758 	restore_pblist = pbe;
2759 	return pbe->address;
2760 }
2761 
2762 /**
2763  * snapshot_write_next - Get the address to store the next image page.
2764  * @handle: Snapshot handle structure to guide the writing.
2765  *
2766  * On the first call, @handle should point to a zeroed snapshot_handle
2767  * structure.  The structure gets populated then and a pointer to it should be
2768  * passed to this function every next time.
2769  *
2770  * On success, the function returns a positive number.  Then, the caller
2771  * is allowed to write up to the returned number of bytes to the memory
2772  * location computed by the data_of() macro.
2773  *
2774  * The function returns 0 to indicate the "end of file" condition.  Negative
2775  * numbers are returned on errors, in which cases the structure pointed to by
2776  * @handle is not updated and should not be used any more.
2777  */
snapshot_write_next(struct snapshot_handle * handle)2778 int snapshot_write_next(struct snapshot_handle *handle)
2779 {
2780 	static struct chain_allocator ca;
2781 	int error = 0;
2782 
2783 next:
2784 	/* Check if we have already loaded the entire image */
2785 	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages)
2786 		return 0;
2787 
2788 	if (!handle->cur) {
2789 		if (!buffer)
2790 			/* This makes the buffer be freed by swsusp_free() */
2791 			buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2792 
2793 		if (!buffer)
2794 			return -ENOMEM;
2795 
2796 		handle->buffer = buffer;
2797 	} else if (handle->cur == 1) {
2798 		error = load_header(buffer);
2799 		if (error)
2800 			return error;
2801 
2802 		safe_pages_list = NULL;
2803 
2804 		error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
2805 		if (error)
2806 			return error;
2807 
2808 		error = memory_bm_create(&zero_bm, GFP_ATOMIC, PG_ANY);
2809 		if (error)
2810 			return error;
2811 
2812 		nr_zero_pages = 0;
2813 
2814 		hibernate_restore_protection_begin();
2815 	} else if (handle->cur <= nr_meta_pages + 1) {
2816 		error = unpack_orig_pfns(buffer, &copy_bm, &zero_bm);
2817 		if (error)
2818 			return error;
2819 
2820 		if (handle->cur == nr_meta_pages + 1) {
2821 			error = prepare_image(&orig_bm, &copy_bm, &zero_bm);
2822 			if (error)
2823 				return error;
2824 
2825 			chain_init(&ca, GFP_ATOMIC, PG_SAFE);
2826 			memory_bm_position_reset(&orig_bm);
2827 			memory_bm_position_reset(&zero_bm);
2828 			restore_pblist = NULL;
2829 			handle->buffer = get_buffer(&orig_bm, &ca);
2830 			if (IS_ERR(handle->buffer))
2831 				return PTR_ERR(handle->buffer);
2832 		}
2833 	} else {
2834 		copy_last_highmem_page();
2835 		hibernate_restore_protect_page(handle->buffer);
2836 		handle->buffer = get_buffer(&orig_bm, &ca);
2837 		if (IS_ERR(handle->buffer))
2838 			return PTR_ERR(handle->buffer);
2839 	}
2840 	handle->sync_read = (handle->buffer == buffer);
2841 	handle->cur++;
2842 
2843 	/* Zero pages were not included in the image, memset it and move on. */
2844 	if (handle->cur > nr_meta_pages + 1 &&
2845 	    memory_bm_test_bit(&zero_bm, memory_bm_get_current(&orig_bm))) {
2846 		memset(handle->buffer, 0, PAGE_SIZE);
2847 		goto next;
2848 	}
2849 
2850 	return PAGE_SIZE;
2851 }
2852 
2853 /**
2854  * snapshot_write_finalize - Complete the loading of a hibernation image.
2855  *
2856  * Must be called after the last call to snapshot_write_next() in case the last
2857  * page in the image happens to be a highmem page and its contents should be
2858  * stored in highmem.  Additionally, it recycles bitmap memory that's not
2859  * necessary any more.
2860  */
snapshot_write_finalize(struct snapshot_handle * handle)2861 void snapshot_write_finalize(struct snapshot_handle *handle)
2862 {
2863 	copy_last_highmem_page();
2864 	hibernate_restore_protect_page(handle->buffer);
2865 	/* Do that only if we have loaded the image entirely */
2866 	if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages + nr_zero_pages) {
2867 		memory_bm_recycle(&orig_bm);
2868 		free_highmem_data();
2869 	}
2870 }
2871 
snapshot_image_loaded(struct snapshot_handle * handle)2872 int snapshot_image_loaded(struct snapshot_handle *handle)
2873 {
2874 	return !(!nr_copy_pages || !last_highmem_page_copied() ||
2875 			handle->cur <= nr_meta_pages + nr_copy_pages + nr_zero_pages);
2876 }
2877 
2878 #ifdef CONFIG_HIGHMEM
2879 /* Assumes that @buf is ready and points to a "safe" page */
swap_two_pages_data(struct page * p1,struct page * p2,void * buf)2880 static inline void swap_two_pages_data(struct page *p1, struct page *p2,
2881 				       void *buf)
2882 {
2883 	void *kaddr1, *kaddr2;
2884 
2885 	kaddr1 = kmap_atomic(p1);
2886 	kaddr2 = kmap_atomic(p2);
2887 	copy_page(buf, kaddr1);
2888 	copy_page(kaddr1, kaddr2);
2889 	copy_page(kaddr2, buf);
2890 	kunmap_atomic(kaddr2);
2891 	kunmap_atomic(kaddr1);
2892 }
2893 
2894 /**
2895  * restore_highmem - Put highmem image pages into their original locations.
2896  *
2897  * For each highmem page that was in use before hibernation and is included in
2898  * the image, and also has been allocated by the "restore" kernel, swap its
2899  * current contents with the previous (ie. "before hibernation") ones.
2900  *
2901  * If the restore eventually fails, we can call this function once again and
2902  * restore the highmem state as seen by the restore kernel.
2903  */
restore_highmem(void)2904 int restore_highmem(void)
2905 {
2906 	struct highmem_pbe *pbe = highmem_pblist;
2907 	void *buf;
2908 
2909 	if (!pbe)
2910 		return 0;
2911 
2912 	buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2913 	if (!buf)
2914 		return -ENOMEM;
2915 
2916 	while (pbe) {
2917 		swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2918 		pbe = pbe->next;
2919 	}
2920 	free_image_page(buf, PG_UNSAFE_CLEAR);
2921 	return 0;
2922 }
2923 #endif /* CONFIG_HIGHMEM */
2924