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Linux/kernel/power/snapshot.c

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  1 // SPDX-License-Identifier: GPL-2.0-only
  2 /*
  3  * linux/kernel/power/snapshot.c
  4  *
  5  * This file provides system snapshot/restore functionality for swsusp.
  6  *
  7  * Copyright (C) 1998-2005 Pavel Machek <pavel@ucw.cz>
  8  * Copyright (C) 2006 Rafael J. Wysocki <rjw@sisk.pl>
  9  */
 10 
 11 #define pr_fmt(fmt) "PM: " 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/pgtable.h>
 38 #include <asm/tlbflush.h>
 39 #include <asm/io.h>
 40 
 41 #include "power.h"
 42 
 43 #if defined(CONFIG_STRICT_KERNEL_RWX) && defined(CONFIG_ARCH_HAS_SET_MEMORY)
 44 static bool hibernate_restore_protection;
 45 static bool hibernate_restore_protection_active;
 46 
 47 void enable_restore_image_protection(void)
 48 {
 49         hibernate_restore_protection = true;
 50 }
 51 
 52 static inline void hibernate_restore_protection_begin(void)
 53 {
 54         hibernate_restore_protection_active = hibernate_restore_protection;
 55 }
 56 
 57 static inline void hibernate_restore_protection_end(void)
 58 {
 59         hibernate_restore_protection_active = false;
 60 }
 61 
 62 static inline void hibernate_restore_protect_page(void *page_address)
 63 {
 64         if (hibernate_restore_protection_active)
 65                 set_memory_ro((unsigned long)page_address, 1);
 66 }
 67 
 68 static inline void hibernate_restore_unprotect_page(void *page_address)
 69 {
 70         if (hibernate_restore_protection_active)
 71                 set_memory_rw((unsigned long)page_address, 1);
 72 }
 73 #else
 74 static inline void hibernate_restore_protection_begin(void) {}
 75 static inline void hibernate_restore_protection_end(void) {}
 76 static inline void hibernate_restore_protect_page(void *page_address) {}
 77 static inline void hibernate_restore_unprotect_page(void *page_address) {}
 78 #endif /* CONFIG_STRICT_KERNEL_RWX  && CONFIG_ARCH_HAS_SET_MEMORY */
 79 
 80 static int swsusp_page_is_free(struct page *);
 81 static void swsusp_set_page_forbidden(struct page *);
 82 static void swsusp_unset_page_forbidden(struct page *);
 83 
 84 /*
 85  * Number of bytes to reserve for memory allocations made by device drivers
 86  * from their ->freeze() and ->freeze_noirq() callbacks so that they don't
 87  * cause image creation to fail (tunable via /sys/power/reserved_size).
 88  */
 89 unsigned long reserved_size;
 90 
 91 void __init hibernate_reserved_size_init(void)
 92 {
 93         reserved_size = SPARE_PAGES * PAGE_SIZE;
 94 }
 95 
 96 /*
 97  * Preferred image size in bytes (tunable via /sys/power/image_size).
 98  * When it is set to N, swsusp will do its best to ensure the image
 99  * size will not exceed N bytes, but if that is impossible, it will
100  * try to create the smallest image possible.
101  */
102 unsigned long image_size;
103 
104 void __init hibernate_image_size_init(void)
105 {
106         image_size = ((totalram_pages() * 2) / 5) * PAGE_SIZE;
107 }
108 
109 /*
110  * List of PBEs needed for restoring the pages that were allocated before
111  * the suspend and included in the suspend image, but have also been
112  * allocated by the "resume" kernel, so their contents cannot be written
113  * directly to their "original" page frames.
114  */
115 struct pbe *restore_pblist;
116 
117 /* struct linked_page is used to build chains of pages */
118 
119 #define LINKED_PAGE_DATA_SIZE   (PAGE_SIZE - sizeof(void *))
120 
121 struct linked_page {
122         struct linked_page *next;
123         char data[LINKED_PAGE_DATA_SIZE];
124 } __packed;
125 
126 /*
127  * List of "safe" pages (ie. pages that were not used by the image kernel
128  * before hibernation) that may be used as temporary storage for image kernel
129  * memory contents.
130  */
131 static struct linked_page *safe_pages_list;
132 
133 /* Pointer to an auxiliary buffer (1 page) */
134 static void *buffer;
135 
136 #define PG_ANY          0
137 #define PG_SAFE         1
138 #define PG_UNSAFE_CLEAR 1
139 #define PG_UNSAFE_KEEP  0
140 
141 static unsigned int allocated_unsafe_pages;
142 
143 /**
144  * get_image_page - Allocate a page for a hibernation image.
145  * @gfp_mask: GFP mask for the allocation.
146  * @safe_needed: Get pages that were not used before hibernation (restore only)
147  *
148  * During image restoration, for storing the PBE list and the image data, we can
149  * only use memory pages that do not conflict with the pages used before
150  * hibernation.  The "unsafe" pages have PageNosaveFree set and we count them
151  * using allocated_unsafe_pages.
152  *
153  * Each allocated image page is marked as PageNosave and PageNosaveFree so that
154  * swsusp_free() can release it.
155  */
156 static void *get_image_page(gfp_t gfp_mask, int safe_needed)
157 {
158         void *res;
159 
160         res = (void *)get_zeroed_page(gfp_mask);
161         if (safe_needed)
162                 while (res && swsusp_page_is_free(virt_to_page(res))) {
163                         /* The page is unsafe, mark it for swsusp_free() */
164                         swsusp_set_page_forbidden(virt_to_page(res));
165                         allocated_unsafe_pages++;
166                         res = (void *)get_zeroed_page(gfp_mask);
167                 }
168         if (res) {
169                 swsusp_set_page_forbidden(virt_to_page(res));
170                 swsusp_set_page_free(virt_to_page(res));
171         }
172         return res;
173 }
174 
175 static void *__get_safe_page(gfp_t gfp_mask)
176 {
177         if (safe_pages_list) {
178                 void *ret = safe_pages_list;
179 
180                 safe_pages_list = safe_pages_list->next;
181                 memset(ret, 0, PAGE_SIZE);
182                 return ret;
183         }
184         return get_image_page(gfp_mask, PG_SAFE);
185 }
186 
187 unsigned long get_safe_page(gfp_t gfp_mask)
188 {
189         return (unsigned long)__get_safe_page(gfp_mask);
190 }
191 
192 static struct page *alloc_image_page(gfp_t gfp_mask)
193 {
194         struct page *page;
195 
196         page = alloc_page(gfp_mask);
197         if (page) {
198                 swsusp_set_page_forbidden(page);
199                 swsusp_set_page_free(page);
200         }
201         return page;
202 }
203 
204 static void recycle_safe_page(void *page_address)
205 {
206         struct linked_page *lp = page_address;
207 
208         lp->next = safe_pages_list;
209         safe_pages_list = lp;
210 }
211 
212 /**
213  * free_image_page - Free a page allocated for hibernation image.
214  * @addr: Address of the page to free.
215  * @clear_nosave_free: If set, clear the PageNosaveFree bit for the page.
216  *
217  * The page to free should have been allocated by get_image_page() (page flags
218  * set by it are affected).
219  */
220 static inline void free_image_page(void *addr, int clear_nosave_free)
221 {
222         struct page *page;
223 
224         BUG_ON(!virt_addr_valid(addr));
225 
226         page = virt_to_page(addr);
227 
228         swsusp_unset_page_forbidden(page);
229         if (clear_nosave_free)
230                 swsusp_unset_page_free(page);
231 
232         __free_page(page);
233 }
234 
235 static inline void free_list_of_pages(struct linked_page *list,
236                                       int clear_page_nosave)
237 {
238         while (list) {
239                 struct linked_page *lp = list->next;
240 
241                 free_image_page(list, clear_page_nosave);
242                 list = lp;
243         }
244 }
245 
246 /*
247  * struct chain_allocator is used for allocating small objects out of
248  * a linked list of pages called 'the chain'.
249  *
250  * The chain grows each time when there is no room for a new object in
251  * the current page.  The allocated objects cannot be freed individually.
252  * It is only possible to free them all at once, by freeing the entire
253  * chain.
254  *
255  * NOTE: The chain allocator may be inefficient if the allocated objects
256  * are not much smaller than PAGE_SIZE.
257  */
258 struct chain_allocator {
259         struct linked_page *chain;      /* the chain */
260         unsigned int used_space;        /* total size of objects allocated out
261                                            of the current page */
262         gfp_t gfp_mask;         /* mask for allocating pages */
263         int safe_needed;        /* if set, only "safe" pages are allocated */
264 };
265 
266 static void chain_init(struct chain_allocator *ca, gfp_t gfp_mask,
267                        int safe_needed)
268 {
269         ca->chain = NULL;
270         ca->used_space = LINKED_PAGE_DATA_SIZE;
271         ca->gfp_mask = gfp_mask;
272         ca->safe_needed = safe_needed;
273 }
274 
275 static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
276 {
277         void *ret;
278 
279         if (LINKED_PAGE_DATA_SIZE - ca->used_space < size) {
280                 struct linked_page *lp;
281 
282                 lp = ca->safe_needed ? __get_safe_page(ca->gfp_mask) :
283                                         get_image_page(ca->gfp_mask, PG_ANY);
284                 if (!lp)
285                         return NULL;
286 
287                 lp->next = ca->chain;
288                 ca->chain = lp;
289                 ca->used_space = 0;
290         }
291         ret = ca->chain->data + ca->used_space;
292         ca->used_space += size;
293         return ret;
294 }
295 
296 /**
297  * Data types related to memory bitmaps.
298  *
299  * Memory bitmap is a structure consiting of many linked lists of
300  * objects.  The main list's elements are of type struct zone_bitmap
301  * and each of them corresonds to one zone.  For each zone bitmap
302  * object there is a list of objects of type struct bm_block that
303  * represent each blocks of bitmap in which information is stored.
304  *
305  * struct memory_bitmap contains a pointer to the main list of zone
306  * bitmap objects, a struct bm_position used for browsing the bitmap,
307  * and a pointer to the list of pages used for allocating all of the
308  * zone bitmap objects and bitmap block objects.
309  *
310  * NOTE: It has to be possible to lay out the bitmap in memory
311  * using only allocations of order 0.  Additionally, the bitmap is
312  * designed to work with arbitrary number of zones (this is over the
313  * top for now, but let's avoid making unnecessary assumptions ;-).
314  *
315  * struct zone_bitmap contains a pointer to a list of bitmap block
316  * objects and a pointer to the bitmap block object that has been
317  * most recently used for setting bits.  Additionally, it contains the
318  * PFNs that correspond to the start and end of the represented zone.
319  *
320  * struct bm_block contains a pointer to the memory page in which
321  * information is stored (in the form of a block of bitmap)
322  * It also contains the pfns that correspond to the start and end of
323  * the represented memory area.
324  *
325  * The memory bitmap is organized as a radix tree to guarantee fast random
326  * access to the bits. There is one radix tree for each zone (as returned
327  * from create_mem_extents).
328  *
329  * One radix tree is represented by one struct mem_zone_bm_rtree. There are
330  * two linked lists for the nodes of the tree, one for the inner nodes and
331  * one for the leave nodes. The linked leave nodes are used for fast linear
332  * access of the memory bitmap.
333  *
334  * The struct rtree_node represents one node of the radix tree.
335  */
336 
337 #define BM_END_OF_MAP   (~0UL)
338 
339 #define BM_BITS_PER_BLOCK       (PAGE_SIZE * BITS_PER_BYTE)
340 #define BM_BLOCK_SHIFT          (PAGE_SHIFT + 3)
341 #define BM_BLOCK_MASK           ((1UL << BM_BLOCK_SHIFT) - 1)
342 
343 /*
344  * struct rtree_node is a wrapper struct to link the nodes
345  * of the rtree together for easy linear iteration over
346  * bits and easy freeing
347  */
348 struct rtree_node {
349         struct list_head list;
350         unsigned long *data;
351 };
352 
353 /*
354  * struct mem_zone_bm_rtree represents a bitmap used for one
355  * populated memory zone.
356  */
357 struct mem_zone_bm_rtree {
358         struct list_head list;          /* Link Zones together         */
359         struct list_head nodes;         /* Radix Tree inner nodes      */
360         struct list_head leaves;        /* Radix Tree leaves           */
361         unsigned long start_pfn;        /* Zone start page frame       */
362         unsigned long end_pfn;          /* Zone end page frame + 1     */
363         struct rtree_node *rtree;       /* Radix Tree Root             */
364         int levels;                     /* Number of Radix Tree Levels */
365         unsigned int blocks;            /* Number of Bitmap Blocks     */
366 };
367 
368 /* strcut bm_position is used for browsing memory bitmaps */
369 
370 struct bm_position {
371         struct mem_zone_bm_rtree *zone;
372         struct rtree_node *node;
373         unsigned long node_pfn;
374         int node_bit;
375 };
376 
377 struct memory_bitmap {
378         struct list_head zones;
379         struct linked_page *p_list;     /* list of pages used to store zone
380                                            bitmap objects and bitmap block
381                                            objects */
382         struct bm_position cur; /* most recently used bit position */
383 };
384 
385 /* Functions that operate on memory bitmaps */
386 
387 #define BM_ENTRIES_PER_LEVEL    (PAGE_SIZE / sizeof(unsigned long))
388 #if BITS_PER_LONG == 32
389 #define BM_RTREE_LEVEL_SHIFT    (PAGE_SHIFT - 2)
390 #else
391 #define BM_RTREE_LEVEL_SHIFT    (PAGE_SHIFT - 3)
392 #endif
393 #define BM_RTREE_LEVEL_MASK     ((1UL << BM_RTREE_LEVEL_SHIFT) - 1)
394 
395 /**
396  * alloc_rtree_node - Allocate a new node and add it to the radix tree.
397  *
398  * This function is used to allocate inner nodes as well as the
399  * leave nodes of the radix tree. It also adds the node to the
400  * corresponding linked list passed in by the *list parameter.
401  */
402 static struct rtree_node *alloc_rtree_node(gfp_t gfp_mask, int safe_needed,
403                                            struct chain_allocator *ca,
404                                            struct list_head *list)
405 {
406         struct rtree_node *node;
407 
408         node = chain_alloc(ca, sizeof(struct rtree_node));
409         if (!node)
410                 return NULL;
411 
412         node->data = get_image_page(gfp_mask, safe_needed);
413         if (!node->data)
414                 return NULL;
415 
416         list_add_tail(&node->list, list);
417 
418         return node;
419 }
420 
421 /**
422  * add_rtree_block - Add a new leave node to the radix tree.
423  *
424  * The leave nodes need to be allocated in order to keep the leaves
425  * linked list in order. This is guaranteed by the zone->blocks
426  * counter.
427  */
428 static int add_rtree_block(struct mem_zone_bm_rtree *zone, gfp_t gfp_mask,
429                            int safe_needed, struct chain_allocator *ca)
430 {
431         struct rtree_node *node, *block, **dst;
432         unsigned int levels_needed, block_nr;
433         int i;
434 
435         block_nr = zone->blocks;
436         levels_needed = 0;
437 
438         /* How many levels do we need for this block nr? */
439         while (block_nr) {
440                 levels_needed += 1;
441                 block_nr >>= BM_RTREE_LEVEL_SHIFT;
442         }
443 
444         /* Make sure the rtree has enough levels */
445         for (i = zone->levels; i < levels_needed; i++) {
446                 node = alloc_rtree_node(gfp_mask, safe_needed, ca,
447                                         &zone->nodes);
448                 if (!node)
449                         return -ENOMEM;
450 
451                 node->data[0] = (unsigned long)zone->rtree;
452                 zone->rtree = node;
453                 zone->levels += 1;
454         }
455 
456         /* Allocate new block */
457         block = alloc_rtree_node(gfp_mask, safe_needed, ca, &zone->leaves);
458         if (!block)
459                 return -ENOMEM;
460 
461         /* Now walk the rtree to insert the block */
462         node = zone->rtree;
463         dst = &zone->rtree;
464         block_nr = zone->blocks;
465         for (i = zone->levels; i > 0; i--) {
466                 int index;
467 
468                 if (!node) {
469                         node = alloc_rtree_node(gfp_mask, safe_needed, ca,
470                                                 &zone->nodes);
471                         if (!node)
472                                 return -ENOMEM;
473                         *dst = node;
474                 }
475 
476                 index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
477                 index &= BM_RTREE_LEVEL_MASK;
478                 dst = (struct rtree_node **)&((*dst)->data[index]);
479                 node = *dst;
480         }
481 
482         zone->blocks += 1;
483         *dst = block;
484 
485         return 0;
486 }
487 
488 static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
489                                int clear_nosave_free);
490 
491 /**
492  * create_zone_bm_rtree - Create a radix tree for one zone.
493  *
494  * Allocated the mem_zone_bm_rtree structure and initializes it.
495  * This function also allocated and builds the radix tree for the
496  * zone.
497  */
498 static struct mem_zone_bm_rtree *create_zone_bm_rtree(gfp_t gfp_mask,
499                                                       int safe_needed,
500                                                       struct chain_allocator *ca,
501                                                       unsigned long start,
502                                                       unsigned long end)
503 {
504         struct mem_zone_bm_rtree *zone;
505         unsigned int i, nr_blocks;
506         unsigned long pages;
507 
508         pages = end - start;
509         zone  = chain_alloc(ca, sizeof(struct mem_zone_bm_rtree));
510         if (!zone)
511                 return NULL;
512 
513         INIT_LIST_HEAD(&zone->nodes);
514         INIT_LIST_HEAD(&zone->leaves);
515         zone->start_pfn = start;
516         zone->end_pfn = end;
517         nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
518 
519         for (i = 0; i < nr_blocks; i++) {
520                 if (add_rtree_block(zone, gfp_mask, safe_needed, ca)) {
521                         free_zone_bm_rtree(zone, PG_UNSAFE_CLEAR);
522                         return NULL;
523                 }
524         }
525 
526         return zone;
527 }
528 
529 /**
530  * free_zone_bm_rtree - Free the memory of the radix tree.
531  *
532  * Free all node pages of the radix tree. The mem_zone_bm_rtree
533  * structure itself is not freed here nor are the rtree_node
534  * structs.
535  */
536 static void free_zone_bm_rtree(struct mem_zone_bm_rtree *zone,
537                                int clear_nosave_free)
538 {
539         struct rtree_node *node;
540 
541         list_for_each_entry(node, &zone->nodes, list)
542                 free_image_page(node->data, clear_nosave_free);
543 
544         list_for_each_entry(node, &zone->leaves, list)
545                 free_image_page(node->data, clear_nosave_free);
546 }
547 
548 static void memory_bm_position_reset(struct memory_bitmap *bm)
549 {
550         bm->cur.zone = list_entry(bm->zones.next, struct mem_zone_bm_rtree,
551                                   list);
552         bm->cur.node = list_entry(bm->cur.zone->leaves.next,
553                                   struct rtree_node, list);
554         bm->cur.node_pfn = 0;
555         bm->cur.node_bit = 0;
556 }
557 
558 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
559 
560 struct mem_extent {
561         struct list_head hook;
562         unsigned long start;
563         unsigned long end;
564 };
565 
566 /**
567  * free_mem_extents - Free a list of memory extents.
568  * @list: List of extents to free.
569  */
570 static void free_mem_extents(struct list_head *list)
571 {
572         struct mem_extent *ext, *aux;
573 
574         list_for_each_entry_safe(ext, aux, list, hook) {
575                 list_del(&ext->hook);
576                 kfree(ext);
577         }
578 }
579 
580 /**
581  * create_mem_extents - Create a list of memory extents.
582  * @list: List to put the extents into.
583  * @gfp_mask: Mask to use for memory allocations.
584  *
585  * The extents represent contiguous ranges of PFNs.
586  */
587 static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
588 {
589         struct zone *zone;
590 
591         INIT_LIST_HEAD(list);
592 
593         for_each_populated_zone(zone) {
594                 unsigned long zone_start, zone_end;
595                 struct mem_extent *ext, *cur, *aux;
596 
597                 zone_start = zone->zone_start_pfn;
598                 zone_end = zone_end_pfn(zone);
599 
600                 list_for_each_entry(ext, list, hook)
601                         if (zone_start <= ext->end)
602                                 break;
603 
604                 if (&ext->hook == list || zone_end < ext->start) {
605                         /* New extent is necessary */
606                         struct mem_extent *new_ext;
607 
608                         new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
609                         if (!new_ext) {
610                                 free_mem_extents(list);
611                                 return -ENOMEM;
612                         }
613                         new_ext->start = zone_start;
614                         new_ext->end = zone_end;
615                         list_add_tail(&new_ext->hook, &ext->hook);
616                         continue;
617                 }
618 
619                 /* Merge this zone's range of PFNs with the existing one */
620                 if (zone_start < ext->start)
621                         ext->start = zone_start;
622                 if (zone_end > ext->end)
623                         ext->end = zone_end;
624 
625                 /* More merging may be possible */
626                 cur = ext;
627                 list_for_each_entry_safe_continue(cur, aux, list, hook) {
628                         if (zone_end < cur->start)
629                                 break;
630                         if (zone_end < cur->end)
631                                 ext->end = cur->end;
632                         list_del(&cur->hook);
633                         kfree(cur);
634                 }
635         }
636 
637         return 0;
638 }
639 
640 /**
641  * memory_bm_create - Allocate memory for a memory bitmap.
642  */
643 static int memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask,
644                             int safe_needed)
645 {
646         struct chain_allocator ca;
647         struct list_head mem_extents;
648         struct mem_extent *ext;
649         int error;
650 
651         chain_init(&ca, gfp_mask, safe_needed);
652         INIT_LIST_HEAD(&bm->zones);
653 
654         error = create_mem_extents(&mem_extents, gfp_mask);
655         if (error)
656                 return error;
657 
658         list_for_each_entry(ext, &mem_extents, hook) {
659                 struct mem_zone_bm_rtree *zone;
660 
661                 zone = create_zone_bm_rtree(gfp_mask, safe_needed, &ca,
662                                             ext->start, ext->end);
663                 if (!zone) {
664                         error = -ENOMEM;
665                         goto Error;
666                 }
667                 list_add_tail(&zone->list, &bm->zones);
668         }
669 
670         bm->p_list = ca.chain;
671         memory_bm_position_reset(bm);
672  Exit:
673         free_mem_extents(&mem_extents);
674         return error;
675 
676  Error:
677         bm->p_list = ca.chain;
678         memory_bm_free(bm, PG_UNSAFE_CLEAR);
679         goto Exit;
680 }
681 
682 /**
683  * memory_bm_free - Free memory occupied by the memory bitmap.
684  * @bm: Memory bitmap.
685  */
686 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
687 {
688         struct mem_zone_bm_rtree *zone;
689 
690         list_for_each_entry(zone, &bm->zones, list)
691                 free_zone_bm_rtree(zone, clear_nosave_free);
692 
693         free_list_of_pages(bm->p_list, clear_nosave_free);
694 
695         INIT_LIST_HEAD(&bm->zones);
696 }
697 
698 /**
699  * memory_bm_find_bit - Find the bit for a given PFN in a memory bitmap.
700  *
701  * Find the bit in memory bitmap @bm that corresponds to the given PFN.
702  * The cur.zone, cur.block and cur.node_pfn members of @bm are updated.
703  *
704  * Walk the radix tree to find the page containing the bit that represents @pfn
705  * and return the position of the bit in @addr and @bit_nr.
706  */
707 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
708                               void **addr, unsigned int *bit_nr)
709 {
710         struct mem_zone_bm_rtree *curr, *zone;
711         struct rtree_node *node;
712         int i, block_nr;
713 
714         zone = bm->cur.zone;
715 
716         if (pfn >= zone->start_pfn && pfn < zone->end_pfn)
717                 goto zone_found;
718 
719         zone = NULL;
720 
721         /* Find the right zone */
722         list_for_each_entry(curr, &bm->zones, list) {
723                 if (pfn >= curr->start_pfn && pfn < curr->end_pfn) {
724                         zone = curr;
725                         break;
726                 }
727         }
728 
729         if (!zone)
730                 return -EFAULT;
731 
732 zone_found:
733         /*
734          * We have found the zone. Now walk the radix tree to find the leaf node
735          * for our PFN.
736          */
737         node = bm->cur.node;
738         if (((pfn - zone->start_pfn) & ~BM_BLOCK_MASK) == bm->cur.node_pfn)
739                 goto node_found;
740 
741         node      = zone->rtree;
742         block_nr  = (pfn - zone->start_pfn) >> BM_BLOCK_SHIFT;
743 
744         for (i = zone->levels; i > 0; i--) {
745                 int index;
746 
747                 index = block_nr >> ((i - 1) * BM_RTREE_LEVEL_SHIFT);
748                 index &= BM_RTREE_LEVEL_MASK;
749                 BUG_ON(node->data[index] == 0);
750                 node = (struct rtree_node *)node->data[index];
751         }
752 
753 node_found:
754         /* Update last position */
755         bm->cur.zone = zone;
756         bm->cur.node = node;
757         bm->cur.node_pfn = (pfn - zone->start_pfn) & ~BM_BLOCK_MASK;
758 
759         /* Set return values */
760         *addr = node->data;
761         *bit_nr = (pfn - zone->start_pfn) & BM_BLOCK_MASK;
762 
763         return 0;
764 }
765 
766 static void memory_bm_set_bit(struct memory_bitmap *bm, unsigned long pfn)
767 {
768         void *addr;
769         unsigned int bit;
770         int error;
771 
772         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
773         BUG_ON(error);
774         set_bit(bit, addr);
775 }
776 
777 static int mem_bm_set_bit_check(struct memory_bitmap *bm, unsigned long pfn)
778 {
779         void *addr;
780         unsigned int bit;
781         int error;
782 
783         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
784         if (!error)
785                 set_bit(bit, addr);
786 
787         return error;
788 }
789 
790 static void memory_bm_clear_bit(struct memory_bitmap *bm, unsigned long pfn)
791 {
792         void *addr;
793         unsigned int bit;
794         int error;
795 
796         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
797         BUG_ON(error);
798         clear_bit(bit, addr);
799 }
800 
801 static void memory_bm_clear_current(struct memory_bitmap *bm)
802 {
803         int bit;
804 
805         bit = max(bm->cur.node_bit - 1, 0);
806         clear_bit(bit, bm->cur.node->data);
807 }
808 
809 static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
810 {
811         void *addr;
812         unsigned int bit;
813         int error;
814 
815         error = memory_bm_find_bit(bm, pfn, &addr, &bit);
816         BUG_ON(error);
817         return test_bit(bit, addr);
818 }
819 
820 static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
821 {
822         void *addr;
823         unsigned int bit;
824 
825         return !memory_bm_find_bit(bm, pfn, &addr, &bit);
826 }
827 
828 /*
829  * rtree_next_node - Jump to the next leaf node.
830  *
831  * Set the position to the beginning of the next node in the
832  * memory bitmap. This is either the next node in the current
833  * zone's radix tree or the first node in the radix tree of the
834  * next zone.
835  *
836  * Return true if there is a next node, false otherwise.
837  */
838 static bool rtree_next_node(struct memory_bitmap *bm)
839 {
840         if (!list_is_last(&bm->cur.node->list, &bm->cur.zone->leaves)) {
841                 bm->cur.node = list_entry(bm->cur.node->list.next,
842                                           struct rtree_node, list);
843                 bm->cur.node_pfn += BM_BITS_PER_BLOCK;
844                 bm->cur.node_bit  = 0;
845                 touch_softlockup_watchdog();
846                 return true;
847         }
848 
849         /* No more nodes, goto next zone */
850         if (!list_is_last(&bm->cur.zone->list, &bm->zones)) {
851                 bm->cur.zone = list_entry(bm->cur.zone->list.next,
852                                   struct mem_zone_bm_rtree, list);
853                 bm->cur.node = list_entry(bm->cur.zone->leaves.next,
854                                           struct rtree_node, list);
855                 bm->cur.node_pfn = 0;
856                 bm->cur.node_bit = 0;
857                 return true;
858         }
859 
860         /* No more zones */
861         return false;
862 }
863 
864 /**
865  * memory_bm_rtree_next_pfn - Find the next set bit in a memory bitmap.
866  * @bm: Memory bitmap.
867  *
868  * Starting from the last returned position this function searches for the next
869  * set bit in @bm and returns the PFN represented by it.  If no more bits are
870  * set, BM_END_OF_MAP is returned.
871  *
872  * It is required to run memory_bm_position_reset() before the first call to
873  * this function for the given memory bitmap.
874  */
875 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
876 {
877         unsigned long bits, pfn, pages;
878         int bit;
879 
880         do {
881                 pages     = bm->cur.zone->end_pfn - bm->cur.zone->start_pfn;
882                 bits      = min(pages - bm->cur.node_pfn, BM_BITS_PER_BLOCK);
883                 bit       = find_next_bit(bm->cur.node->data, bits,
884                                           bm->cur.node_bit);
885                 if (bit < bits) {
886                         pfn = bm->cur.zone->start_pfn + bm->cur.node_pfn + bit;
887                         bm->cur.node_bit = bit + 1;
888                         return pfn;
889                 }
890         } while (rtree_next_node(bm));
891 
892         return BM_END_OF_MAP;
893 }
894 
895 /*
896  * This structure represents a range of page frames the contents of which
897  * should not be saved during hibernation.
898  */
899 struct nosave_region {
900         struct list_head list;
901         unsigned long start_pfn;
902         unsigned long end_pfn;
903 };
904 
905 static LIST_HEAD(nosave_regions);
906 
907 static void recycle_zone_bm_rtree(struct mem_zone_bm_rtree *zone)
908 {
909         struct rtree_node *node;
910 
911         list_for_each_entry(node, &zone->nodes, list)
912                 recycle_safe_page(node->data);
913 
914         list_for_each_entry(node, &zone->leaves, list)
915                 recycle_safe_page(node->data);
916 }
917 
918 static void memory_bm_recycle(struct memory_bitmap *bm)
919 {
920         struct mem_zone_bm_rtree *zone;
921         struct linked_page *p_list;
922 
923         list_for_each_entry(zone, &bm->zones, list)
924                 recycle_zone_bm_rtree(zone);
925 
926         p_list = bm->p_list;
927         while (p_list) {
928                 struct linked_page *lp = p_list;
929 
930                 p_list = lp->next;
931                 recycle_safe_page(lp);
932         }
933 }
934 
935 /**
936  * register_nosave_region - Register a region of unsaveable memory.
937  *
938  * Register a range of page frames the contents of which should not be saved
939  * during hibernation (to be used in the early initialization code).
940  */
941 void __init __register_nosave_region(unsigned long start_pfn,
942                                      unsigned long end_pfn, int use_kmalloc)
943 {
944         struct nosave_region *region;
945 
946         if (start_pfn >= end_pfn)
947                 return;
948 
949         if (!list_empty(&nosave_regions)) {
950                 /* Try to extend the previous region (they should be sorted) */
951                 region = list_entry(nosave_regions.prev,
952                                         struct nosave_region, list);
953                 if (region->end_pfn == start_pfn) {
954                         region->end_pfn = end_pfn;
955                         goto Report;
956                 }
957         }
958         if (use_kmalloc) {
959                 /* During init, this shouldn't fail */
960                 region = kmalloc(sizeof(struct nosave_region), GFP_KERNEL);
961                 BUG_ON(!region);
962         } else {
963                 /* This allocation cannot fail */
964                 region = memblock_alloc(sizeof(struct nosave_region),
965                                         SMP_CACHE_BYTES);
966                 if (!region)
967                         panic("%s: Failed to allocate %zu bytes\n", __func__,
968                               sizeof(struct nosave_region));
969         }
970         region->start_pfn = start_pfn;
971         region->end_pfn = end_pfn;
972         list_add_tail(&region->list, &nosave_regions);
973  Report:
974         pr_info("Registered nosave memory: [mem %#010llx-%#010llx]\n",
975                 (unsigned long long) start_pfn << PAGE_SHIFT,
976                 ((unsigned long long) end_pfn << PAGE_SHIFT) - 1);
977 }
978 
979 /*
980  * Set bits in this map correspond to the page frames the contents of which
981  * should not be saved during the suspend.
982  */
983 static struct memory_bitmap *forbidden_pages_map;
984 
985 /* Set bits in this map correspond to free page frames. */
986 static struct memory_bitmap *free_pages_map;
987 
988 /*
989  * Each page frame allocated for creating the image is marked by setting the
990  * corresponding bits in forbidden_pages_map and free_pages_map simultaneously
991  */
992 
993 void swsusp_set_page_free(struct page *page)
994 {
995         if (free_pages_map)
996                 memory_bm_set_bit(free_pages_map, page_to_pfn(page));
997 }
998 
999 static int swsusp_page_is_free(struct page *page)
1000 {
1001         return free_pages_map ?
1002                 memory_bm_test_bit(free_pages_map, page_to_pfn(page)) : 0;
1003 }
1004 
1005 void swsusp_unset_page_free(struct page *page)
1006 {
1007         if (free_pages_map)
1008                 memory_bm_clear_bit(free_pages_map, page_to_pfn(page));
1009 }
1010 
1011 static void swsusp_set_page_forbidden(struct page *page)
1012 {
1013         if (forbidden_pages_map)
1014                 memory_bm_set_bit(forbidden_pages_map, page_to_pfn(page));
1015 }
1016 
1017 int swsusp_page_is_forbidden(struct page *page)
1018 {
1019         return forbidden_pages_map ?
1020                 memory_bm_test_bit(forbidden_pages_map, page_to_pfn(page)) : 0;
1021 }
1022 
1023 static void swsusp_unset_page_forbidden(struct page *page)
1024 {
1025         if (forbidden_pages_map)
1026                 memory_bm_clear_bit(forbidden_pages_map, page_to_pfn(page));
1027 }
1028 
1029 /**
1030  * mark_nosave_pages - Mark pages that should not be saved.
1031  * @bm: Memory bitmap.
1032  *
1033  * Set the bits in @bm that correspond to the page frames the contents of which
1034  * should not be saved.
1035  */
1036 static void mark_nosave_pages(struct memory_bitmap *bm)
1037 {
1038         struct nosave_region *region;
1039 
1040         if (list_empty(&nosave_regions))
1041                 return;
1042 
1043         list_for_each_entry(region, &nosave_regions, list) {
1044                 unsigned long pfn;
1045 
1046                 pr_debug("Marking nosave pages: [mem %#010llx-%#010llx]\n",
1047                          (unsigned long long) region->start_pfn << PAGE_SHIFT,
1048                          ((unsigned long long) region->end_pfn << PAGE_SHIFT)
1049                                 - 1);
1050 
1051                 for (pfn = region->start_pfn; pfn < region->end_pfn; pfn++)
1052                         if (pfn_valid(pfn)) {
1053                                 /*
1054                                  * It is safe to ignore the result of
1055                                  * mem_bm_set_bit_check() here, since we won't
1056                                  * touch the PFNs for which the error is
1057                                  * returned anyway.
1058                                  */
1059                                 mem_bm_set_bit_check(bm, pfn);
1060                         }
1061         }
1062 }
1063 
1064 /**
1065  * create_basic_memory_bitmaps - Create bitmaps to hold basic page information.
1066  *
1067  * Create bitmaps needed for marking page frames that should not be saved and
1068  * free page frames.  The forbidden_pages_map and free_pages_map pointers are
1069  * only modified if everything goes well, because we don't want the bits to be
1070  * touched before both bitmaps are set up.
1071  */
1072 int create_basic_memory_bitmaps(void)
1073 {
1074         struct memory_bitmap *bm1, *bm2;
1075         int error = 0;
1076 
1077         if (forbidden_pages_map && free_pages_map)
1078                 return 0;
1079         else
1080                 BUG_ON(forbidden_pages_map || free_pages_map);
1081 
1082         bm1 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
1083         if (!bm1)
1084                 return -ENOMEM;
1085 
1086         error = memory_bm_create(bm1, GFP_KERNEL, PG_ANY);
1087         if (error)
1088                 goto Free_first_object;
1089 
1090         bm2 = kzalloc(sizeof(struct memory_bitmap), GFP_KERNEL);
1091         if (!bm2)
1092                 goto Free_first_bitmap;
1093 
1094         error = memory_bm_create(bm2, GFP_KERNEL, PG_ANY);
1095         if (error)
1096                 goto Free_second_object;
1097 
1098         forbidden_pages_map = bm1;
1099         free_pages_map = bm2;
1100         mark_nosave_pages(forbidden_pages_map);
1101 
1102         pr_debug("Basic memory bitmaps created\n");
1103 
1104         return 0;
1105 
1106  Free_second_object:
1107         kfree(bm2);
1108  Free_first_bitmap:
1109         memory_bm_free(bm1, PG_UNSAFE_CLEAR);
1110  Free_first_object:
1111         kfree(bm1);
1112         return -ENOMEM;
1113 }
1114 
1115 /**
1116  * free_basic_memory_bitmaps - Free memory bitmaps holding basic information.
1117  *
1118  * Free memory bitmaps allocated by create_basic_memory_bitmaps().  The
1119  * auxiliary pointers are necessary so that the bitmaps themselves are not
1120  * referred to while they are being freed.
1121  */
1122 void free_basic_memory_bitmaps(void)
1123 {
1124         struct memory_bitmap *bm1, *bm2;
1125 
1126         if (WARN_ON(!(forbidden_pages_map && free_pages_map)))
1127                 return;
1128 
1129         bm1 = forbidden_pages_map;
1130         bm2 = free_pages_map;
1131         forbidden_pages_map = NULL;
1132         free_pages_map = NULL;
1133         memory_bm_free(bm1, PG_UNSAFE_CLEAR);
1134         kfree(bm1);
1135         memory_bm_free(bm2, PG_UNSAFE_CLEAR);
1136         kfree(bm2);
1137 
1138         pr_debug("Basic memory bitmaps freed\n");
1139 }
1140 
1141 void clear_free_pages(void)
1142 {
1143 #ifdef CONFIG_PAGE_POISONING_ZERO
1144         struct memory_bitmap *bm = free_pages_map;
1145         unsigned long pfn;
1146 
1147         if (WARN_ON(!(free_pages_map)))
1148                 return;
1149 
1150         memory_bm_position_reset(bm);
1151         pfn = memory_bm_next_pfn(bm);
1152         while (pfn != BM_END_OF_MAP) {
1153                 if (pfn_valid(pfn))
1154                         clear_highpage(pfn_to_page(pfn));
1155 
1156                 pfn = memory_bm_next_pfn(bm);
1157         }
1158         memory_bm_position_reset(bm);
1159         pr_info("free pages cleared after restore\n");
1160 #endif /* PAGE_POISONING_ZERO */
1161 }
1162 
1163 /**
1164  * snapshot_additional_pages - Estimate the number of extra pages needed.
1165  * @zone: Memory zone to carry out the computation for.
1166  *
1167  * Estimate the number of additional pages needed for setting up a hibernation
1168  * image data structures for @zone (usually, the returned value is greater than
1169  * the exact number).
1170  */
1171 unsigned int snapshot_additional_pages(struct zone *zone)
1172 {
1173         unsigned int rtree, nodes;
1174 
1175         rtree = nodes = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
1176         rtree += DIV_ROUND_UP(rtree * sizeof(struct rtree_node),
1177                               LINKED_PAGE_DATA_SIZE);
1178         while (nodes > 1) {
1179                 nodes = DIV_ROUND_UP(nodes, BM_ENTRIES_PER_LEVEL);
1180                 rtree += nodes;
1181         }
1182 
1183         return 2 * rtree;
1184 }
1185 
1186 #ifdef CONFIG_HIGHMEM
1187 /**
1188  * count_free_highmem_pages - Compute the total number of free highmem pages.
1189  *
1190  * The returned number is system-wide.
1191  */
1192 static unsigned int count_free_highmem_pages(void)
1193 {
1194         struct zone *zone;
1195         unsigned int cnt = 0;
1196 
1197         for_each_populated_zone(zone)
1198                 if (is_highmem(zone))
1199                         cnt += zone_page_state(zone, NR_FREE_PAGES);
1200 
1201         return cnt;
1202 }
1203 
1204 /**
1205  * saveable_highmem_page - Check if a highmem page is saveable.
1206  *
1207  * Determine whether a highmem page should be included in a hibernation image.
1208  *
1209  * We should save the page if it isn't Nosave or NosaveFree, or Reserved,
1210  * and it isn't part of a free chunk of pages.
1211  */
1212 static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
1213 {
1214         struct page *page;
1215 
1216         if (!pfn_valid(pfn))
1217                 return NULL;
1218 
1219         page = pfn_to_online_page(pfn);
1220         if (!page || page_zone(page) != zone)
1221                 return NULL;
1222 
1223         BUG_ON(!PageHighMem(page));
1224 
1225         if (swsusp_page_is_forbidden(page) ||  swsusp_page_is_free(page))
1226                 return NULL;
1227 
1228         if (PageReserved(page) || PageOffline(page))
1229                 return NULL;
1230 
1231         if (page_is_guard(page))
1232                 return NULL;
1233 
1234         return page;
1235 }
1236 
1237 /**
1238  * count_highmem_pages - Compute the total number of saveable highmem pages.
1239  */
1240 static unsigned int count_highmem_pages(void)
1241 {
1242         struct zone *zone;
1243         unsigned int n = 0;
1244 
1245         for_each_populated_zone(zone) {
1246                 unsigned long pfn, max_zone_pfn;
1247 
1248                 if (!is_highmem(zone))
1249                         continue;
1250 
1251                 mark_free_pages(zone);
1252                 max_zone_pfn = zone_end_pfn(zone);
1253                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1254                         if (saveable_highmem_page(zone, pfn))
1255                                 n++;
1256         }
1257         return n;
1258 }
1259 #else
1260 static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
1261 {
1262         return NULL;
1263 }
1264 #endif /* CONFIG_HIGHMEM */
1265 
1266 /**
1267  * saveable_page - Check if the given page is saveable.
1268  *
1269  * Determine whether a non-highmem page should be included in a hibernation
1270  * image.
1271  *
1272  * We should save the page if it isn't Nosave, and is not in the range
1273  * of pages statically defined as 'unsaveable', and it isn't part of
1274  * a free chunk of pages.
1275  */
1276 static struct page *saveable_page(struct zone *zone, unsigned long pfn)
1277 {
1278         struct page *page;
1279 
1280         if (!pfn_valid(pfn))
1281                 return NULL;
1282 
1283         page = pfn_to_online_page(pfn);
1284         if (!page || page_zone(page) != zone)
1285                 return NULL;
1286 
1287         BUG_ON(PageHighMem(page));
1288 
1289         if (swsusp_page_is_forbidden(page) || swsusp_page_is_free(page))
1290                 return NULL;
1291 
1292         if (PageOffline(page))
1293                 return NULL;
1294 
1295         if (PageReserved(page)
1296             && (!kernel_page_present(page) || pfn_is_nosave(pfn)))
1297                 return NULL;
1298 
1299         if (page_is_guard(page))
1300                 return NULL;
1301 
1302         return page;
1303 }
1304 
1305 /**
1306  * count_data_pages - Compute the total number of saveable non-highmem pages.
1307  */
1308 static unsigned int count_data_pages(void)
1309 {
1310         struct zone *zone;
1311         unsigned long pfn, max_zone_pfn;
1312         unsigned int n = 0;
1313 
1314         for_each_populated_zone(zone) {
1315                 if (is_highmem(zone))
1316                         continue;
1317 
1318                 mark_free_pages(zone);
1319                 max_zone_pfn = zone_end_pfn(zone);
1320                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1321                         if (saveable_page(zone, pfn))
1322                                 n++;
1323         }
1324         return n;
1325 }
1326 
1327 /*
1328  * This is needed, because copy_page and memcpy are not usable for copying
1329  * task structs.
1330  */
1331 static inline void do_copy_page(long *dst, long *src)
1332 {
1333         int n;
1334 
1335         for (n = PAGE_SIZE / sizeof(long); n; n--)
1336                 *dst++ = *src++;
1337 }
1338 
1339 /**
1340  * safe_copy_page - Copy a page in a safe way.
1341  *
1342  * Check if the page we are going to copy is marked as present in the kernel
1343  * page tables. This always is the case if CONFIG_DEBUG_PAGEALLOC or
1344  * CONFIG_ARCH_HAS_SET_DIRECT_MAP is not set. In that case kernel_page_present()
1345  * always returns 'true'.
1346  */
1347 static void safe_copy_page(void *dst, struct page *s_page)
1348 {
1349         if (kernel_page_present(s_page)) {
1350                 do_copy_page(dst, page_address(s_page));
1351         } else {
1352                 kernel_map_pages(s_page, 1, 1);
1353                 do_copy_page(dst, page_address(s_page));
1354                 kernel_map_pages(s_page, 1, 0);
1355         }
1356 }
1357 
1358 #ifdef CONFIG_HIGHMEM
1359 static inline struct page *page_is_saveable(struct zone *zone, unsigned long pfn)
1360 {
1361         return is_highmem(zone) ?
1362                 saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
1363 }
1364 
1365 static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1366 {
1367         struct page *s_page, *d_page;
1368         void *src, *dst;
1369 
1370         s_page = pfn_to_page(src_pfn);
1371         d_page = pfn_to_page(dst_pfn);
1372         if (PageHighMem(s_page)) {
1373                 src = kmap_atomic(s_page);
1374                 dst = kmap_atomic(d_page);
1375                 do_copy_page(dst, src);
1376                 kunmap_atomic(dst);
1377                 kunmap_atomic(src);
1378         } else {
1379                 if (PageHighMem(d_page)) {
1380                         /*
1381                          * The page pointed to by src may contain some kernel
1382                          * data modified by kmap_atomic()
1383                          */
1384                         safe_copy_page(buffer, s_page);
1385                         dst = kmap_atomic(d_page);
1386                         copy_page(dst, buffer);
1387                         kunmap_atomic(dst);
1388                 } else {
1389                         safe_copy_page(page_address(d_page), s_page);
1390                 }
1391         }
1392 }
1393 #else
1394 #define page_is_saveable(zone, pfn)     saveable_page(zone, pfn)
1395 
1396 static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
1397 {
1398         safe_copy_page(page_address(pfn_to_page(dst_pfn)),
1399                                 pfn_to_page(src_pfn));
1400 }
1401 #endif /* CONFIG_HIGHMEM */
1402 
1403 static void copy_data_pages(struct memory_bitmap *copy_bm,
1404                             struct memory_bitmap *orig_bm)
1405 {
1406         struct zone *zone;
1407         unsigned long pfn;
1408 
1409         for_each_populated_zone(zone) {
1410                 unsigned long max_zone_pfn;
1411 
1412                 mark_free_pages(zone);
1413                 max_zone_pfn = zone_end_pfn(zone);
1414                 for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
1415                         if (page_is_saveable(zone, pfn))
1416                                 memory_bm_set_bit(orig_bm, pfn);
1417         }
1418         memory_bm_position_reset(orig_bm);
1419         memory_bm_position_reset(copy_bm);
1420         for(;;) {
1421                 pfn = memory_bm_next_pfn(orig_bm);
1422                 if (unlikely(pfn == BM_END_OF_MAP))
1423                         break;
1424                 copy_data_page(memory_bm_next_pfn(copy_bm), pfn);
1425         }
1426 }
1427 
1428 /* Total number of image pages */
1429 static unsigned int nr_copy_pages;
1430 /* Number of pages needed for saving the original pfns of the image pages */
1431 static unsigned int nr_meta_pages;
1432 /*
1433  * Numbers of normal and highmem page frames allocated for hibernation image
1434  * before suspending devices.
1435  */
1436 static unsigned int alloc_normal, alloc_highmem;
1437 /*
1438  * Memory bitmap used for marking saveable pages (during hibernation) or
1439  * hibernation image pages (during restore)
1440  */
1441 static struct memory_bitmap orig_bm;
1442 /*
1443  * Memory bitmap used during hibernation for marking allocated page frames that
1444  * will contain copies of saveable pages.  During restore it is initially used
1445  * for marking hibernation image pages, but then the set bits from it are
1446  * duplicated in @orig_bm and it is released.  On highmem systems it is next
1447  * used for marking "safe" highmem pages, but it has to be reinitialized for
1448  * this purpose.
1449  */
1450 static struct memory_bitmap copy_bm;
1451 
1452 /**
1453  * swsusp_free - Free pages allocated for hibernation image.
1454  *
1455  * Image pages are alocated before snapshot creation, so they need to be
1456  * released after resume.
1457  */
1458 void swsusp_free(void)
1459 {
1460         unsigned long fb_pfn, fr_pfn;
1461 
1462         if (!forbidden_pages_map || !free_pages_map)
1463                 goto out;
1464 
1465         memory_bm_position_reset(forbidden_pages_map);
1466         memory_bm_position_reset(free_pages_map);
1467 
1468 loop:
1469         fr_pfn = memory_bm_next_pfn(free_pages_map);
1470         fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
1471 
1472         /*
1473          * Find the next bit set in both bitmaps. This is guaranteed to
1474          * terminate when fb_pfn == fr_pfn == BM_END_OF_MAP.
1475          */
1476         do {
1477                 if (fb_pfn < fr_pfn)
1478                         fb_pfn = memory_bm_next_pfn(forbidden_pages_map);
1479                 if (fr_pfn < fb_pfn)
1480                         fr_pfn = memory_bm_next_pfn(free_pages_map);
1481         } while (fb_pfn != fr_pfn);
1482 
1483         if (fr_pfn != BM_END_OF_MAP && pfn_valid(fr_pfn)) {
1484                 struct page *page = pfn_to_page(fr_pfn);
1485 
1486                 memory_bm_clear_current(forbidden_pages_map);
1487                 memory_bm_clear_current(free_pages_map);
1488                 hibernate_restore_unprotect_page(page_address(page));
1489                 __free_page(page);
1490                 goto loop;
1491         }
1492 
1493 out:
1494         nr_copy_pages = 0;
1495         nr_meta_pages = 0;
1496         restore_pblist = NULL;
1497         buffer = NULL;
1498         alloc_normal = 0;
1499         alloc_highmem = 0;
1500         hibernate_restore_protection_end();
1501 }
1502 
1503 /* Helper functions used for the shrinking of memory. */
1504 
1505 #define GFP_IMAGE       (GFP_KERNEL | __GFP_NOWARN)
1506 
1507 /**
1508  * preallocate_image_pages - Allocate a number of pages for hibernation image.
1509  * @nr_pages: Number of page frames to allocate.
1510  * @mask: GFP flags to use for the allocation.
1511  *
1512  * Return value: Number of page frames actually allocated
1513  */
1514 static unsigned long preallocate_image_pages(unsigned long nr_pages, gfp_t mask)
1515 {
1516         unsigned long nr_alloc = 0;
1517 
1518         while (nr_pages > 0) {
1519                 struct page *page;
1520 
1521                 page = alloc_image_page(mask);
1522                 if (!page)
1523                         break;
1524                 memory_bm_set_bit(&copy_bm, page_to_pfn(page));
1525                 if (PageHighMem(page))
1526                         alloc_highmem++;
1527                 else
1528                         alloc_normal++;
1529                 nr_pages--;
1530                 nr_alloc++;
1531         }
1532 
1533         return nr_alloc;
1534 }
1535 
1536 static unsigned long preallocate_image_memory(unsigned long nr_pages,
1537                                               unsigned long avail_normal)
1538 {
1539         unsigned long alloc;
1540 
1541         if (avail_normal <= alloc_normal)
1542                 return 0;
1543 
1544         alloc = avail_normal - alloc_normal;
1545         if (nr_pages < alloc)
1546                 alloc = nr_pages;
1547 
1548         return preallocate_image_pages(alloc, GFP_IMAGE);
1549 }
1550 
1551 #ifdef CONFIG_HIGHMEM
1552 static unsigned long preallocate_image_highmem(unsigned long nr_pages)
1553 {
1554         return preallocate_image_pages(nr_pages, GFP_IMAGE | __GFP_HIGHMEM);
1555 }
1556 
1557 /**
1558  *  __fraction - Compute (an approximation of) x * (multiplier / base).
1559  */
1560 static unsigned long __fraction(u64 x, u64 multiplier, u64 base)
1561 {
1562         x *= multiplier;
1563         do_div(x, base);
1564         return (unsigned long)x;
1565 }
1566 
1567 static unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1568                                                   unsigned long highmem,
1569                                                   unsigned long total)
1570 {
1571         unsigned long alloc = __fraction(nr_pages, highmem, total);
1572 
1573         return preallocate_image_pages(alloc, GFP_IMAGE | __GFP_HIGHMEM);
1574 }
1575 #else /* CONFIG_HIGHMEM */
1576 static inline unsigned long preallocate_image_highmem(unsigned long nr_pages)
1577 {
1578         return 0;
1579 }
1580 
1581 static inline unsigned long preallocate_highmem_fraction(unsigned long nr_pages,
1582                                                          unsigned long highmem,
1583                                                          unsigned long total)
1584 {
1585         return 0;
1586 }
1587 #endif /* CONFIG_HIGHMEM */
1588 
1589 /**
1590  * free_unnecessary_pages - Release preallocated pages not needed for the image.
1591  */
1592 static unsigned long free_unnecessary_pages(void)
1593 {
1594         unsigned long save, to_free_normal, to_free_highmem, free;
1595 
1596         save = count_data_pages();
1597         if (alloc_normal >= save) {
1598                 to_free_normal = alloc_normal - save;
1599                 save = 0;
1600         } else {
1601                 to_free_normal = 0;
1602                 save -= alloc_normal;
1603         }
1604         save += count_highmem_pages();
1605         if (alloc_highmem >= save) {
1606                 to_free_highmem = alloc_highmem - save;
1607         } else {
1608                 to_free_highmem = 0;
1609                 save -= alloc_highmem;
1610                 if (to_free_normal > save)
1611                         to_free_normal -= save;
1612                 else
1613                         to_free_normal = 0;
1614         }
1615         free = to_free_normal + to_free_highmem;
1616 
1617         memory_bm_position_reset(&copy_bm);
1618 
1619         while (to_free_normal > 0 || to_free_highmem > 0) {
1620                 unsigned long pfn = memory_bm_next_pfn(&copy_bm);
1621                 struct page *page = pfn_to_page(pfn);
1622 
1623                 if (PageHighMem(page)) {
1624                         if (!to_free_highmem)
1625                                 continue;
1626                         to_free_highmem--;
1627                         alloc_highmem--;
1628                 } else {
1629                         if (!to_free_normal)
1630                                 continue;
1631                         to_free_normal--;
1632                         alloc_normal--;
1633                 }
1634                 memory_bm_clear_bit(&copy_bm, pfn);
1635                 swsusp_unset_page_forbidden(page);
1636                 swsusp_unset_page_free(page);
1637                 __free_page(page);
1638         }
1639 
1640         return free;
1641 }
1642 
1643 /**
1644  * minimum_image_size - Estimate the minimum acceptable size of an image.
1645  * @saveable: Number of saveable pages in the system.
1646  *
1647  * We want to avoid attempting to free too much memory too hard, so estimate the
1648  * minimum acceptable size of a hibernation image to use as the lower limit for
1649  * preallocating memory.
1650  *
1651  * We assume that the minimum image size should be proportional to
1652  *
1653  * [number of saveable pages] - [number of pages that can be freed in theory]
1654  *
1655  * where the second term is the sum of (1) reclaimable slab pages, (2) active
1656  * and (3) inactive anonymous pages, (4) active and (5) inactive file pages.
1657  */
1658 static unsigned long minimum_image_size(unsigned long saveable)
1659 {
1660         unsigned long size;
1661 
1662         size = global_node_page_state(NR_SLAB_RECLAIMABLE)
1663                 + global_node_page_state(NR_ACTIVE_ANON)
1664                 + global_node_page_state(NR_INACTIVE_ANON)
1665                 + global_node_page_state(NR_ACTIVE_FILE)
1666                 + global_node_page_state(NR_INACTIVE_FILE);
1667 
1668         return saveable <= size ? 0 : saveable - size;
1669 }
1670 
1671 /**
1672  * hibernate_preallocate_memory - Preallocate memory for hibernation image.
1673  *
1674  * To create a hibernation image it is necessary to make a copy of every page
1675  * frame in use.  We also need a number of page frames to be free during
1676  * hibernation for allocations made while saving the image and for device
1677  * drivers, in case they need to allocate memory from their hibernation
1678  * callbacks (these two numbers are given by PAGES_FOR_IO (which is a rough
1679  * estimate) and reserverd_size divided by PAGE_SIZE (which is tunable through
1680  * /sys/power/reserved_size, respectively).  To make this happen, we compute the
1681  * total number of available page frames and allocate at least
1682  *
1683  * ([page frames total] + PAGES_FOR_IO + [metadata pages]) / 2
1684  *  + 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE)
1685  *
1686  * of them, which corresponds to the maximum size of a hibernation image.
1687  *
1688  * If image_size is set below the number following from the above formula,
1689  * the preallocation of memory is continued until the total number of saveable
1690  * pages in the system is below the requested image size or the minimum
1691  * acceptable image size returned by minimum_image_size(), whichever is greater.
1692  */
1693 int hibernate_preallocate_memory(void)
1694 {
1695         struct zone *zone;
1696         unsigned long saveable, size, max_size, count, highmem, pages = 0;
1697         unsigned long alloc, save_highmem, pages_highmem, avail_normal;
1698         ktime_t start, stop;
1699         int error;
1700 
1701         pr_info("Preallocating image memory... ");
1702         start = ktime_get();
1703 
1704         error = memory_bm_create(&orig_bm, GFP_IMAGE, PG_ANY);
1705         if (error)
1706                 goto err_out;
1707 
1708         error = memory_bm_create(&copy_bm, GFP_IMAGE, PG_ANY);
1709         if (error)
1710                 goto err_out;
1711 
1712         alloc_normal = 0;
1713         alloc_highmem = 0;
1714 
1715         /* Count the number of saveable data pages. */
1716         save_highmem = count_highmem_pages();
1717         saveable = count_data_pages();
1718 
1719         /*
1720          * Compute the total number of page frames we can use (count) and the
1721          * number of pages needed for image metadata (size).
1722          */
1723         count = saveable;
1724         saveable += save_highmem;
1725         highmem = save_highmem;
1726         size = 0;
1727         for_each_populated_zone(zone) {
1728                 size += snapshot_additional_pages(zone);
1729                 if (is_highmem(zone))
1730                         highmem += zone_page_state(zone, NR_FREE_PAGES);
1731                 else
1732                         count += zone_page_state(zone, NR_FREE_PAGES);
1733         }
1734         avail_normal = count;
1735         count += highmem;
1736         count -= totalreserve_pages;
1737 
1738         /* Add number of pages required for page keys (s390 only). */
1739         size += page_key_additional_pages(saveable);
1740 
1741         /* Compute the maximum number of saveable pages to leave in memory. */
1742         max_size = (count - (size + PAGES_FOR_IO)) / 2
1743                         - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
1744         /* Compute the desired number of image pages specified by image_size. */
1745         size = DIV_ROUND_UP(image_size, PAGE_SIZE);
1746         if (size > max_size)
1747                 size = max_size;
1748         /*
1749          * If the desired number of image pages is at least as large as the
1750          * current number of saveable pages in memory, allocate page frames for
1751          * the image and we're done.
1752          */
1753         if (size >= saveable) {
1754                 pages = preallocate_image_highmem(save_highmem);
1755                 pages += preallocate_image_memory(saveable - pages, avail_normal);
1756                 goto out;
1757         }
1758 
1759         /* Estimate the minimum size of the image. */
1760         pages = minimum_image_size(saveable);
1761         /*
1762          * To avoid excessive pressure on the normal zone, leave room in it to
1763          * accommodate an image of the minimum size (unless it's already too
1764          * small, in which case don't preallocate pages from it at all).
1765          */
1766         if (avail_normal > pages)
1767                 avail_normal -= pages;
1768         else
1769                 avail_normal = 0;
1770         if (size < pages)
1771                 size = min_t(unsigned long, pages, max_size);
1772 
1773         /*
1774          * Let the memory management subsystem know that we're going to need a
1775          * large number of page frames to allocate and make it free some memory.
1776          * NOTE: If this is not done, performance will be hurt badly in some
1777          * test cases.
1778          */
1779         shrink_all_memory(saveable - size);
1780 
1781         /*
1782          * The number of saveable pages in memory was too high, so apply some
1783          * pressure to decrease it.  First, make room for the largest possible
1784          * image and fail if that doesn't work.  Next, try to decrease the size
1785          * of the image as much as indicated by 'size' using allocations from
1786          * highmem and non-highmem zones separately.
1787          */
1788         pages_highmem = preallocate_image_highmem(highmem / 2);
1789         alloc = count - max_size;
1790         if (alloc > pages_highmem)
1791                 alloc -= pages_highmem;
1792         else
1793                 alloc = 0;
1794         pages = preallocate_image_memory(alloc, avail_normal);
1795         if (pages < alloc) {
1796                 /* We have exhausted non-highmem pages, try highmem. */
1797                 alloc -= pages;
1798                 pages += pages_highmem;
1799                 pages_highmem = preallocate_image_highmem(alloc);
1800                 if (pages_highmem < alloc)
1801                         goto err_out;
1802                 pages += pages_highmem;
1803                 /*
1804                  * size is the desired number of saveable pages to leave in
1805                  * memory, so try to preallocate (all memory - size) pages.
1806                  */
1807                 alloc = (count - pages) - size;
1808                 pages += preallocate_image_highmem(alloc);
1809         } else {
1810                 /*
1811                  * There are approximately max_size saveable pages at this point
1812                  * and we want to reduce this number down to size.
1813                  */
1814                 alloc = max_size - size;
1815                 size = preallocate_highmem_fraction(alloc, highmem, count);
1816                 pages_highmem += size;
1817                 alloc -= size;
1818                 size = preallocate_image_memory(alloc, avail_normal);
1819                 pages_highmem += preallocate_image_highmem(alloc - size);
1820                 pages += pages_highmem + size;
1821         }
1822 
1823         /*
1824          * We only need as many page frames for the image as there are saveable
1825          * pages in memory, but we have allocated more.  Release the excessive
1826          * ones now.
1827          */
1828         pages -= free_unnecessary_pages();
1829 
1830  out:
1831         stop = ktime_get();
1832         pr_cont("done (allocated %lu pages)\n", pages);
1833         swsusp_show_speed(start, stop, pages, "Allocated");
1834 
1835         return 0;
1836 
1837  err_out:
1838         pr_cont("\n");
1839         swsusp_free();
1840         return -ENOMEM;
1841 }
1842 
1843 #ifdef CONFIG_HIGHMEM
1844 /**
1845  * count_pages_for_highmem - Count non-highmem pages needed for copying highmem.
1846  *
1847  * Compute the number of non-highmem pages that will be necessary for creating
1848  * copies of highmem pages.
1849  */
1850 static unsigned int count_pages_for_highmem(unsigned int nr_highmem)
1851 {
1852         unsigned int free_highmem = count_free_highmem_pages() + alloc_highmem;
1853 
1854         if (free_highmem >= nr_highmem)
1855                 nr_highmem = 0;
1856         else
1857                 nr_highmem -= free_highmem;
1858 
1859         return nr_highmem;
1860 }
1861 #else
1862 static unsigned int count_pages_for_highmem(unsigned int nr_highmem) { return 0; }
1863 #endif /* CONFIG_HIGHMEM */
1864 
1865 /**
1866  * enough_free_mem - Check if there is enough free memory for the image.
1867  */
1868 static int enough_free_mem(unsigned int nr_pages, unsigned int nr_highmem)
1869 {
1870         struct zone *zone;
1871         unsigned int free = alloc_normal;
1872 
1873         for_each_populated_zone(zone)
1874                 if (!is_highmem(zone))
1875                         free += zone_page_state(zone, NR_FREE_PAGES);
1876 
1877         nr_pages += count_pages_for_highmem(nr_highmem);
1878         pr_debug("Normal pages needed: %u + %u, available pages: %u\n",
1879                  nr_pages, PAGES_FOR_IO, free);
1880 
1881         return free > nr_pages + PAGES_FOR_IO;
1882 }
1883 
1884 #ifdef CONFIG_HIGHMEM
1885 /**
1886  * get_highmem_buffer - Allocate a buffer for highmem pages.
1887  *
1888  * If there are some highmem pages in the hibernation image, we may need a
1889  * buffer to copy them and/or load their data.
1890  */
1891 static inline int get_highmem_buffer(int safe_needed)
1892 {
1893         buffer = get_image_page(GFP_ATOMIC, safe_needed);
1894         return buffer ? 0 : -ENOMEM;
1895 }
1896 
1897 /**
1898  * alloc_highmem_image_pages - Allocate some highmem pages for the image.
1899  *
1900  * Try to allocate as many pages as needed, but if the number of free highmem
1901  * pages is less than that, allocate them all.
1902  */
1903 static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
1904                                                unsigned int nr_highmem)
1905 {
1906         unsigned int to_alloc = count_free_highmem_pages();
1907 
1908         if (to_alloc > nr_highmem)
1909                 to_alloc = nr_highmem;
1910 
1911         nr_highmem -= to_alloc;
1912         while (to_alloc-- > 0) {
1913                 struct page *page;
1914 
1915                 page = alloc_image_page(__GFP_HIGHMEM|__GFP_KSWAPD_RECLAIM);
1916                 memory_bm_set_bit(bm, page_to_pfn(page));
1917         }
1918         return nr_highmem;
1919 }
1920 #else
1921 static inline int get_highmem_buffer(int safe_needed) { return 0; }
1922 
1923 static inline unsigned int alloc_highmem_pages(struct memory_bitmap *bm,
1924                                                unsigned int n) { return 0; }
1925 #endif /* CONFIG_HIGHMEM */
1926 
1927 /**
1928  * swsusp_alloc - Allocate memory for hibernation image.
1929  *
1930  * We first try to allocate as many highmem pages as there are
1931  * saveable highmem pages in the system.  If that fails, we allocate
1932  * non-highmem pages for the copies of the remaining highmem ones.
1933  *
1934  * In this approach it is likely that the copies of highmem pages will
1935  * also be located in the high memory, because of the way in which
1936  * copy_data_pages() works.
1937  */
1938 static int swsusp_alloc(struct memory_bitmap *copy_bm,
1939                         unsigned int nr_pages, unsigned int nr_highmem)
1940 {
1941         if (nr_highmem > 0) {
1942                 if (get_highmem_buffer(PG_ANY))
1943                         goto err_out;
1944                 if (nr_highmem > alloc_highmem) {
1945                         nr_highmem -= alloc_highmem;
1946                         nr_pages += alloc_highmem_pages(copy_bm, nr_highmem);
1947                 }
1948         }
1949         if (nr_pages > alloc_normal) {
1950                 nr_pages -= alloc_normal;
1951                 while (nr_pages-- > 0) {
1952                         struct page *page;
1953 
1954                         page = alloc_image_page(GFP_ATOMIC);
1955                         if (!page)
1956                                 goto err_out;
1957                         memory_bm_set_bit(copy_bm, page_to_pfn(page));
1958                 }
1959         }
1960 
1961         return 0;
1962 
1963  err_out:
1964         swsusp_free();
1965         return -ENOMEM;
1966 }
1967 
1968 asmlinkage __visible int swsusp_save(void)
1969 {
1970         unsigned int nr_pages, nr_highmem;
1971 
1972         pr_info("Creating hibernation image:\n");
1973 
1974         drain_local_pages(NULL);
1975         nr_pages = count_data_pages();
1976         nr_highmem = count_highmem_pages();
1977         pr_info("Need to copy %u pages\n", nr_pages + nr_highmem);
1978 
1979         if (!enough_free_mem(nr_pages, nr_highmem)) {
1980                 pr_err("Not enough free memory\n");
1981                 return -ENOMEM;
1982         }
1983 
1984         if (swsusp_alloc(&copy_bm, nr_pages, nr_highmem)) {
1985                 pr_err("Memory allocation failed\n");
1986                 return -ENOMEM;
1987         }
1988 
1989         /*
1990          * During allocating of suspend pagedir, new cold pages may appear.
1991          * Kill them.
1992          */
1993         drain_local_pages(NULL);
1994         copy_data_pages(&copy_bm, &orig_bm);
1995 
1996         /*
1997          * End of critical section. From now on, we can write to memory,
1998          * but we should not touch disk. This specially means we must _not_
1999          * touch swap space! Except we must write out our image of course.
2000          */
2001 
2002         nr_pages += nr_highmem;
2003         nr_copy_pages = nr_pages;
2004         nr_meta_pages = DIV_ROUND_UP(nr_pages * sizeof(long), PAGE_SIZE);
2005 
2006         pr_info("Hibernation image created (%d pages copied)\n", nr_pages);
2007 
2008         return 0;
2009 }
2010 
2011 #ifndef CONFIG_ARCH_HIBERNATION_HEADER
2012 static int init_header_complete(struct swsusp_info *info)
2013 {
2014         memcpy(&info->uts, init_utsname(), sizeof(struct new_utsname));
2015         info->version_code = LINUX_VERSION_CODE;
2016         return 0;
2017 }
2018 
2019 static char *check_image_kernel(struct swsusp_info *info)
2020 {
2021         if (info->version_code != LINUX_VERSION_CODE)
2022                 return "kernel version";
2023         if (strcmp(info->uts.sysname,init_utsname()->sysname))
2024                 return "system type";
2025         if (strcmp(info->uts.release,init_utsname()->release))
2026                 return "kernel release";
2027         if (strcmp(info->uts.version,init_utsname()->version))
2028                 return "version";
2029         if (strcmp(info->uts.machine,init_utsname()->machine))
2030                 return "machine";
2031         return NULL;
2032 }
2033 #endif /* CONFIG_ARCH_HIBERNATION_HEADER */
2034 
2035 unsigned long snapshot_get_image_size(void)
2036 {
2037         return nr_copy_pages + nr_meta_pages + 1;
2038 }
2039 
2040 static int init_header(struct swsusp_info *info)
2041 {
2042         memset(info, 0, sizeof(struct swsusp_info));
2043         info->num_physpages = get_num_physpages();
2044         info->image_pages = nr_copy_pages;
2045         info->pages = snapshot_get_image_size();
2046         info->size = info->pages;
2047         info->size <<= PAGE_SHIFT;
2048         return init_header_complete(info);
2049 }
2050 
2051 /**
2052  * pack_pfns - Prepare PFNs for saving.
2053  * @bm: Memory bitmap.
2054  * @buf: Memory buffer to store the PFNs in.
2055  *
2056  * PFNs corresponding to set bits in @bm are stored in the area of memory
2057  * pointed to by @buf (1 page at a time).
2058  */
2059 static inline void pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
2060 {
2061         int j;
2062 
2063         for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2064                 buf[j] = memory_bm_next_pfn(bm);
2065                 if (unlikely(buf[j] == BM_END_OF_MAP))
2066                         break;
2067                 /* Save page key for data page (s390 only). */
2068                 page_key_read(buf + j);
2069         }
2070 }
2071 
2072 /**
2073  * snapshot_read_next - Get the address to read the next image page from.
2074  * @handle: Snapshot handle to be used for the reading.
2075  *
2076  * On the first call, @handle should point to a zeroed snapshot_handle
2077  * structure.  The structure gets populated then and a pointer to it should be
2078  * passed to this function every next time.
2079  *
2080  * On success, the function returns a positive number.  Then, the caller
2081  * is allowed to read up to the returned number of bytes from the memory
2082  * location computed by the data_of() macro.
2083  *
2084  * The function returns 0 to indicate the end of the data stream condition,
2085  * and negative numbers are returned on errors.  If that happens, the structure
2086  * pointed to by @handle is not updated and should not be used any more.
2087  */
2088 int snapshot_read_next(struct snapshot_handle *handle)
2089 {
2090         if (handle->cur > nr_meta_pages + nr_copy_pages)
2091                 return 0;
2092 
2093         if (!buffer) {
2094                 /* This makes the buffer be freed by swsusp_free() */
2095                 buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2096                 if (!buffer)
2097                         return -ENOMEM;
2098         }
2099         if (!handle->cur) {
2100                 int error;
2101 
2102                 error = init_header((struct swsusp_info *)buffer);
2103                 if (error)
2104                         return error;
2105                 handle->buffer = buffer;
2106                 memory_bm_position_reset(&orig_bm);
2107                 memory_bm_position_reset(&copy_bm);
2108         } else if (handle->cur <= nr_meta_pages) {
2109                 clear_page(buffer);
2110                 pack_pfns(buffer, &orig_bm);
2111         } else {
2112                 struct page *page;
2113 
2114                 page = pfn_to_page(memory_bm_next_pfn(&copy_bm));
2115                 if (PageHighMem(page)) {
2116                         /*
2117                          * Highmem pages are copied to the buffer,
2118                          * because we can't return with a kmapped
2119                          * highmem page (we may not be called again).
2120                          */
2121                         void *kaddr;
2122 
2123                         kaddr = kmap_atomic(page);
2124                         copy_page(buffer, kaddr);
2125                         kunmap_atomic(kaddr);
2126                         handle->buffer = buffer;
2127                 } else {
2128                         handle->buffer = page_address(page);
2129                 }
2130         }
2131         handle->cur++;
2132         return PAGE_SIZE;
2133 }
2134 
2135 static void duplicate_memory_bitmap(struct memory_bitmap *dst,
2136                                     struct memory_bitmap *src)
2137 {
2138         unsigned long pfn;
2139 
2140         memory_bm_position_reset(src);
2141         pfn = memory_bm_next_pfn(src);
2142         while (pfn != BM_END_OF_MAP) {
2143                 memory_bm_set_bit(dst, pfn);
2144                 pfn = memory_bm_next_pfn(src);
2145         }
2146 }
2147 
2148 /**
2149  * mark_unsafe_pages - Mark pages that were used before hibernation.
2150  *
2151  * Mark the pages that cannot be used for storing the image during restoration,
2152  * because they conflict with the pages that had been used before hibernation.
2153  */
2154 static void mark_unsafe_pages(struct memory_bitmap *bm)
2155 {
2156         unsigned long pfn;
2157 
2158         /* Clear the "free"/"unsafe" bit for all PFNs */
2159         memory_bm_position_reset(free_pages_map);
2160         pfn = memory_bm_next_pfn(free_pages_map);
2161         while (pfn != BM_END_OF_MAP) {
2162                 memory_bm_clear_current(free_pages_map);
2163                 pfn = memory_bm_next_pfn(free_pages_map);
2164         }
2165 
2166         /* Mark pages that correspond to the "original" PFNs as "unsafe" */
2167         duplicate_memory_bitmap(free_pages_map, bm);
2168 
2169         allocated_unsafe_pages = 0;
2170 }
2171 
2172 static int check_header(struct swsusp_info *info)
2173 {
2174         char *reason;
2175 
2176         reason = check_image_kernel(info);
2177         if (!reason && info->num_physpages != get_num_physpages())
2178                 reason = "memory size";
2179         if (reason) {
2180                 pr_err("Image mismatch: %s\n", reason);
2181                 return -EPERM;
2182         }
2183         return 0;
2184 }
2185 
2186 /**
2187  * load header - Check the image header and copy the data from it.
2188  */
2189 static int load_header(struct swsusp_info *info)
2190 {
2191         int error;
2192 
2193         restore_pblist = NULL;
2194         error = check_header(info);
2195         if (!error) {
2196                 nr_copy_pages = info->image_pages;
2197                 nr_meta_pages = info->pages - info->image_pages - 1;
2198         }
2199         return error;
2200 }
2201 
2202 /**
2203  * unpack_orig_pfns - Set bits corresponding to given PFNs in a memory bitmap.
2204  * @bm: Memory bitmap.
2205  * @buf: Area of memory containing the PFNs.
2206  *
2207  * For each element of the array pointed to by @buf (1 page at a time), set the
2208  * corresponding bit in @bm.
2209  */
2210 static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
2211 {
2212         int j;
2213 
2214         for (j = 0; j < PAGE_SIZE / sizeof(long); j++) {
2215                 if (unlikely(buf[j] == BM_END_OF_MAP))
2216                         break;
2217 
2218                 /* Extract and buffer page key for data page (s390 only). */
2219                 page_key_memorize(buf + j);
2220 
2221                 if (pfn_valid(buf[j]) && memory_bm_pfn_present(bm, buf[j]))
2222                         memory_bm_set_bit(bm, buf[j]);
2223                 else
2224                         return -EFAULT;
2225         }
2226 
2227         return 0;
2228 }
2229 
2230 #ifdef CONFIG_HIGHMEM
2231 /*
2232  * struct highmem_pbe is used for creating the list of highmem pages that
2233  * should be restored atomically during the resume from disk, because the page
2234  * frames they have occupied before the suspend are in use.
2235  */
2236 struct highmem_pbe {
2237         struct page *copy_page; /* data is here now */
2238         struct page *orig_page; /* data was here before the suspend */
2239         struct highmem_pbe *next;
2240 };
2241 
2242 /*
2243  * List of highmem PBEs needed for restoring the highmem pages that were
2244  * allocated before the suspend and included in the suspend image, but have
2245  * also been allocated by the "resume" kernel, so their contents cannot be
2246  * written directly to their "original" page frames.
2247  */
2248 static struct highmem_pbe *highmem_pblist;
2249 
2250 /**
2251  * count_highmem_image_pages - Compute the number of highmem pages in the image.
2252  * @bm: Memory bitmap.
2253  *
2254  * The bits in @bm that correspond to image pages are assumed to be set.
2255  */
2256 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm)
2257 {
2258         unsigned long pfn;
2259         unsigned int cnt = 0;
2260 
2261         memory_bm_position_reset(bm);
2262         pfn = memory_bm_next_pfn(bm);
2263         while (pfn != BM_END_OF_MAP) {
2264                 if (PageHighMem(pfn_to_page(pfn)))
2265                         cnt++;
2266 
2267                 pfn = memory_bm_next_pfn(bm);
2268         }
2269         return cnt;
2270 }
2271 
2272 static unsigned int safe_highmem_pages;
2273 
2274 static struct memory_bitmap *safe_highmem_bm;
2275 
2276 /**
2277  * prepare_highmem_image - Allocate memory for loading highmem data from image.
2278  * @bm: Pointer to an uninitialized memory bitmap structure.
2279  * @nr_highmem_p: Pointer to the number of highmem image pages.
2280  *
2281  * Try to allocate as many highmem pages as there are highmem image pages
2282  * (@nr_highmem_p points to the variable containing the number of highmem image
2283  * pages).  The pages that are "safe" (ie. will not be overwritten when the
2284  * hibernation image is restored entirely) have the corresponding bits set in
2285  * @bm (it must be unitialized).
2286  *
2287  * NOTE: This function should not be called if there are no highmem image pages.
2288  */
2289 static int prepare_highmem_image(struct memory_bitmap *bm,
2290                                  unsigned int *nr_highmem_p)
2291 {
2292         unsigned int to_alloc;
2293 
2294         if (memory_bm_create(bm, GFP_ATOMIC, PG_SAFE))
2295                 return -ENOMEM;
2296 
2297         if (get_highmem_buffer(PG_SAFE))
2298                 return -ENOMEM;
2299 
2300         to_alloc = count_free_highmem_pages();
2301         if (to_alloc > *nr_highmem_p)
2302                 to_alloc = *nr_highmem_p;
2303         else
2304                 *nr_highmem_p = to_alloc;
2305 
2306         safe_highmem_pages = 0;
2307         while (to_alloc-- > 0) {
2308                 struct page *page;
2309 
2310                 page = alloc_page(__GFP_HIGHMEM);
2311                 if (!swsusp_page_is_free(page)) {
2312                         /* The page is "safe", set its bit the bitmap */
2313                         memory_bm_set_bit(bm, page_to_pfn(page));
2314                         safe_highmem_pages++;
2315                 }
2316                 /* Mark the page as allocated */
2317                 swsusp_set_page_forbidden(page);
2318                 swsusp_set_page_free(page);
2319         }
2320         memory_bm_position_reset(bm);
2321         safe_highmem_bm = bm;
2322         return 0;
2323 }
2324 
2325 static struct page *last_highmem_page;
2326 
2327 /**
2328  * get_highmem_page_buffer - Prepare a buffer to store a highmem image page.
2329  *
2330  * For a given highmem image page get a buffer that suspend_write_next() should
2331  * return to its caller to write to.
2332  *
2333  * If the page is to be saved to its "original" page frame or a copy of
2334  * the page is to be made in the highmem, @buffer is returned.  Otherwise,
2335  * the copy of the page is to be made in normal memory, so the address of
2336  * the copy is returned.
2337  *
2338  * If @buffer is returned, the caller of suspend_write_next() will write
2339  * the page's contents to @buffer, so they will have to be copied to the
2340  * right location on the next call to suspend_write_next() and it is done
2341  * with the help of copy_last_highmem_page().  For this purpose, if
2342  * @buffer is returned, @last_highmem_page is set to the page to which
2343  * the data will have to be copied from @buffer.
2344  */
2345 static void *get_highmem_page_buffer(struct page *page,
2346                                      struct chain_allocator *ca)
2347 {
2348         struct highmem_pbe *pbe;
2349         void *kaddr;
2350 
2351         if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page)) {
2352                 /*
2353                  * We have allocated the "original" page frame and we can
2354                  * use it directly to store the loaded page.
2355                  */
2356                 last_highmem_page = page;
2357                 return buffer;
2358         }
2359         /*
2360          * The "original" page frame has not been allocated and we have to
2361          * use a "safe" page frame to store the loaded page.
2362          */
2363         pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
2364         if (!pbe) {
2365                 swsusp_free();
2366                 return ERR_PTR(-ENOMEM);
2367         }
2368         pbe->orig_page = page;
2369         if (safe_highmem_pages > 0) {
2370                 struct page *tmp;
2371 
2372                 /* Copy of the page will be stored in high memory */
2373                 kaddr = buffer;
2374                 tmp = pfn_to_page(memory_bm_next_pfn(safe_highmem_bm));
2375                 safe_highmem_pages--;
2376                 last_highmem_page = tmp;
2377                 pbe->copy_page = tmp;
2378         } else {
2379                 /* Copy of the page will be stored in normal memory */
2380                 kaddr = safe_pages_list;
2381                 safe_pages_list = safe_pages_list->next;
2382                 pbe->copy_page = virt_to_page(kaddr);
2383         }
2384         pbe->next = highmem_pblist;
2385         highmem_pblist = pbe;
2386         return kaddr;
2387 }
2388 
2389 /**
2390  * copy_last_highmem_page - Copy most the most recent highmem image page.
2391  *
2392  * Copy the contents of a highmem image from @buffer, where the caller of
2393  * snapshot_write_next() has stored them, to the right location represented by
2394  * @last_highmem_page .
2395  */
2396 static void copy_last_highmem_page(void)
2397 {
2398         if (last_highmem_page) {
2399                 void *dst;
2400 
2401                 dst = kmap_atomic(last_highmem_page);
2402                 copy_page(dst, buffer);
2403                 kunmap_atomic(dst);
2404                 last_highmem_page = NULL;
2405         }
2406 }
2407 
2408 static inline int last_highmem_page_copied(void)
2409 {
2410         return !last_highmem_page;
2411 }
2412 
2413 static inline void free_highmem_data(void)
2414 {
2415         if (safe_highmem_bm)
2416                 memory_bm_free(safe_highmem_bm, PG_UNSAFE_CLEAR);
2417 
2418         if (buffer)
2419                 free_image_page(buffer, PG_UNSAFE_CLEAR);
2420 }
2421 #else
2422 static unsigned int count_highmem_image_pages(struct memory_bitmap *bm) { return 0; }
2423 
2424 static inline int prepare_highmem_image(struct memory_bitmap *bm,
2425                                         unsigned int *nr_highmem_p) { return 0; }
2426 
2427 static inline void *get_highmem_page_buffer(struct page *page,
2428                                             struct chain_allocator *ca)
2429 {
2430         return ERR_PTR(-EINVAL);
2431 }
2432 
2433 static inline void copy_last_highmem_page(void) {}
2434 static inline int last_highmem_page_copied(void) { return 1; }
2435 static inline void free_highmem_data(void) {}
2436 #endif /* CONFIG_HIGHMEM */
2437 
2438 #define PBES_PER_LINKED_PAGE    (LINKED_PAGE_DATA_SIZE / sizeof(struct pbe))
2439 
2440 /**
2441  * prepare_image - Make room for loading hibernation image.
2442  * @new_bm: Unitialized memory bitmap structure.
2443  * @bm: Memory bitmap with unsafe pages marked.
2444  *
2445  * Use @bm to mark the pages that will be overwritten in the process of
2446  * restoring the system memory state from the suspend image ("unsafe" pages)
2447  * and allocate memory for the image.
2448  *
2449  * The idea is to allocate a new memory bitmap first and then allocate
2450  * as many pages as needed for image data, but without specifying what those
2451  * pages will be used for just yet.  Instead, we mark them all as allocated and
2452  * create a lists of "safe" pages to be used later.  On systems with high
2453  * memory a list of "safe" highmem pages is created too.
2454  */
2455 static int prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
2456 {
2457         unsigned int nr_pages, nr_highmem;
2458         struct linked_page *lp;
2459         int error;
2460 
2461         /* If there is no highmem, the buffer will not be necessary */
2462         free_image_page(buffer, PG_UNSAFE_CLEAR);
2463         buffer = NULL;
2464 
2465         nr_highmem = count_highmem_image_pages(bm);
2466         mark_unsafe_pages(bm);
2467 
2468         error = memory_bm_create(new_bm, GFP_ATOMIC, PG_SAFE);
2469         if (error)
2470                 goto Free;
2471 
2472         duplicate_memory_bitmap(new_bm, bm);
2473         memory_bm_free(bm, PG_UNSAFE_KEEP);
2474         if (nr_highmem > 0) {
2475                 error = prepare_highmem_image(bm, &nr_highmem);
2476                 if (error)
2477                         goto Free;
2478         }
2479         /*
2480          * Reserve some safe pages for potential later use.
2481          *
2482          * NOTE: This way we make sure there will be enough safe pages for the
2483          * chain_alloc() in get_buffer().  It is a bit wasteful, but
2484          * nr_copy_pages cannot be greater than 50% of the memory anyway.
2485          *
2486          * nr_copy_pages cannot be less than allocated_unsafe_pages too.
2487          */
2488         nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2489         nr_pages = DIV_ROUND_UP(nr_pages, PBES_PER_LINKED_PAGE);
2490         while (nr_pages > 0) {
2491                 lp = get_image_page(GFP_ATOMIC, PG_SAFE);
2492                 if (!lp) {
2493                         error = -ENOMEM;
2494                         goto Free;
2495                 }
2496                 lp->next = safe_pages_list;
2497                 safe_pages_list = lp;
2498                 nr_pages--;
2499         }
2500         /* Preallocate memory for the image */
2501         nr_pages = nr_copy_pages - nr_highmem - allocated_unsafe_pages;
2502         while (nr_pages > 0) {
2503                 lp = (struct linked_page *)get_zeroed_page(GFP_ATOMIC);
2504                 if (!lp) {
2505                         error = -ENOMEM;
2506                         goto Free;
2507                 }
2508                 if (!swsusp_page_is_free(virt_to_page(lp))) {
2509                         /* The page is "safe", add it to the list */
2510                         lp->next = safe_pages_list;
2511                         safe_pages_list = lp;
2512                 }
2513                 /* Mark the page as allocated */
2514                 swsusp_set_page_forbidden(virt_to_page(lp));
2515                 swsusp_set_page_free(virt_to_page(lp));
2516                 nr_pages--;
2517         }
2518         return 0;
2519 
2520  Free:
2521         swsusp_free();
2522         return error;
2523 }
2524 
2525 /**
2526  * get_buffer - Get the address to store the next image data page.
2527  *
2528  * Get the address that snapshot_write_next() should return to its caller to
2529  * write to.
2530  */
2531 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
2532 {
2533         struct pbe *pbe;
2534         struct page *page;
2535         unsigned long pfn = memory_bm_next_pfn(bm);
2536 
2537         if (pfn == BM_END_OF_MAP)
2538                 return ERR_PTR(-EFAULT);
2539 
2540         page = pfn_to_page(pfn);
2541         if (PageHighMem(page))
2542                 return get_highmem_page_buffer(page, ca);
2543 
2544         if (swsusp_page_is_forbidden(page) && swsusp_page_is_free(page))
2545                 /*
2546                  * We have allocated the "original" page frame and we can
2547                  * use it directly to store the loaded page.
2548                  */
2549                 return page_address(page);
2550 
2551         /*
2552          * The "original" page frame has not been allocated and we have to
2553          * use a "safe" page frame to store the loaded page.
2554          */
2555         pbe = chain_alloc(ca, sizeof(struct pbe));
2556         if (!pbe) {
2557                 swsusp_free();
2558                 return ERR_PTR(-ENOMEM);
2559         }
2560         pbe->orig_address = page_address(page);
2561         pbe->address = safe_pages_list;
2562         safe_pages_list = safe_pages_list->next;
2563         pbe->next = restore_pblist;
2564         restore_pblist = pbe;
2565         return pbe->address;
2566 }
2567 
2568 /**
2569  * snapshot_write_next - Get the address to store the next image page.
2570  * @handle: Snapshot handle structure to guide the writing.
2571  *
2572  * On the first call, @handle should point to a zeroed snapshot_handle
2573  * structure.  The structure gets populated then and a pointer to it should be
2574  * passed to this function every next time.
2575  *
2576  * On success, the function returns a positive number.  Then, the caller
2577  * is allowed to write up to the returned number of bytes to the memory
2578  * location computed by the data_of() macro.
2579  *
2580  * The function returns 0 to indicate the "end of file" condition.  Negative
2581  * numbers are returned on errors, in which cases the structure pointed to by
2582  * @handle is not updated and should not be used any more.
2583  */
2584 int snapshot_write_next(struct snapshot_handle *handle)
2585 {
2586         static struct chain_allocator ca;
2587         int error = 0;
2588 
2589         /* Check if we have already loaded the entire image */
2590         if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages)
2591                 return 0;
2592 
2593         handle->sync_read = 1;
2594 
2595         if (!handle->cur) {
2596                 if (!buffer)
2597                         /* This makes the buffer be freed by swsusp_free() */
2598                         buffer = get_image_page(GFP_ATOMIC, PG_ANY);
2599 
2600                 if (!buffer)
2601                         return -ENOMEM;
2602 
2603                 handle->buffer = buffer;
2604         } else if (handle->cur == 1) {
2605                 error = load_header(buffer);
2606                 if (error)
2607                         return error;
2608 
2609                 safe_pages_list = NULL;
2610 
2611                 error = memory_bm_create(&copy_bm, GFP_ATOMIC, PG_ANY);
2612                 if (error)
2613                         return error;
2614 
2615                 /* Allocate buffer for page keys. */
2616                 error = page_key_alloc(nr_copy_pages);
2617                 if (error)
2618                         return error;
2619 
2620                 hibernate_restore_protection_begin();
2621         } else if (handle->cur <= nr_meta_pages + 1) {
2622                 error = unpack_orig_pfns(buffer, &copy_bm);
2623                 if (error)
2624                         return error;
2625 
2626                 if (handle->cur == nr_meta_pages + 1) {
2627                         error = prepare_image(&orig_bm, &copy_bm);
2628                         if (error)
2629                                 return error;
2630 
2631                         chain_init(&ca, GFP_ATOMIC, PG_SAFE);
2632                         memory_bm_position_reset(&orig_bm);
2633                         restore_pblist = NULL;
2634                         handle->buffer = get_buffer(&orig_bm, &ca);
2635                         handle->sync_read = 0;
2636                         if (IS_ERR(handle->buffer))
2637                                 return PTR_ERR(handle->buffer);
2638                 }
2639         } else {
2640                 copy_last_highmem_page();
2641                 /* Restore page key for data page (s390 only). */
2642                 page_key_write(handle->buffer);
2643                 hibernate_restore_protect_page(handle->buffer);
2644                 handle->buffer = get_buffer(&orig_bm, &ca);
2645                 if (IS_ERR(handle->buffer))
2646                         return PTR_ERR(handle->buffer);
2647                 if (handle->buffer != buffer)
2648                         handle->sync_read = 0;
2649         }
2650         handle->cur++;
2651         return PAGE_SIZE;
2652 }
2653 
2654 /**
2655  * snapshot_write_finalize - Complete the loading of a hibernation image.
2656  *
2657  * Must be called after the last call to snapshot_write_next() in case the last
2658  * page in the image happens to be a highmem page and its contents should be
2659  * stored in highmem.  Additionally, it recycles bitmap memory that's not
2660  * necessary any more.
2661  */
2662 void snapshot_write_finalize(struct snapshot_handle *handle)
2663 {
2664         copy_last_highmem_page();
2665         /* Restore page key for data page (s390 only). */
2666         page_key_write(handle->buffer);
2667         page_key_free();
2668         hibernate_restore_protect_page(handle->buffer);
2669         /* Do that only if we have loaded the image entirely */
2670         if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
2671                 memory_bm_recycle(&orig_bm);
2672                 free_highmem_data();
2673         }
2674 }
2675 
2676 int snapshot_image_loaded(struct snapshot_handle *handle)
2677 {
2678         return !(!nr_copy_pages || !last_highmem_page_copied() ||
2679                         handle->cur <= nr_meta_pages + nr_copy_pages);
2680 }
2681 
2682 #ifdef CONFIG_HIGHMEM
2683 /* Assumes that @buf is ready and points to a "safe" page */
2684 static inline void swap_two_pages_data(struct page *p1, struct page *p2,
2685                                        void *buf)
2686 {
2687         void *kaddr1, *kaddr2;
2688 
2689         kaddr1 = kmap_atomic(p1);
2690         kaddr2 = kmap_atomic(p2);
2691         copy_page(buf, kaddr1);
2692         copy_page(kaddr1, kaddr2);
2693         copy_page(kaddr2, buf);
2694         kunmap_atomic(kaddr2);
2695         kunmap_atomic(kaddr1);
2696 }
2697 
2698 /**
2699  * restore_highmem - Put highmem image pages into their original locations.
2700  *
2701  * For each highmem page that was in use before hibernation and is included in
2702  * the image, and also has been allocated by the "restore" kernel, swap its
2703  * current contents with the previous (ie. "before hibernation") ones.
2704  *
2705  * If the restore eventually fails, we can call this function once again and
2706  * restore the highmem state as seen by the restore kernel.
2707  */
2708 int restore_highmem(void)
2709 {
2710         struct highmem_pbe *pbe = highmem_pblist;
2711         void *buf;
2712 
2713         if (!pbe)
2714                 return 0;
2715 
2716         buf = get_image_page(GFP_ATOMIC, PG_SAFE);
2717         if (!buf)
2718                 return -ENOMEM;
2719 
2720         while (pbe) {
2721                 swap_two_pages_data(pbe->copy_page, pbe->orig_page, buf);
2722                 pbe = pbe->next;
2723         }
2724         free_image_page(buf, PG_UNSAFE_CLEAR);
2725         return 0;
2726 }
2727 #endif /* CONFIG_HIGHMEM */
2728 

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