2 * linux/kernel/power/snapshot.c
4 * This file provide system snapshot/restore functionality.
6 * Copyright (C) 1998-2005 Pavel Machek <pavel@suse.cz>
8 * This file is released under the GPLv2, and is based on swsusp.c.
13 #include <linux/version.h>
14 #include <linux/module.h>
16 #include <linux/suspend.h>
17 #include <linux/smp_lock.h>
18 #include <linux/delay.h>
19 #include <linux/bitops.h>
20 #include <linux/spinlock.h>
21 #include <linux/kernel.h>
23 #include <linux/device.h>
24 #include <linux/bootmem.h>
25 #include <linux/syscalls.h>
26 #include <linux/console.h>
27 #include <linux/highmem.h>
29 #include <asm/uaccess.h>
30 #include <asm/mmu_context.h>
31 #include <asm/pgtable.h>
32 #include <asm/tlbflush.h>
37 struct pbe
*pagedir_nosave
;
38 static unsigned int nr_copy_pages
;
39 static unsigned int nr_meta_pages
;
42 unsigned int count_highmem_pages(void)
45 unsigned long zone_pfn
;
49 if (is_highmem(zone
)) {
50 mark_free_pages(zone
);
51 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; zone_pfn
++) {
53 unsigned long pfn
= zone_pfn
+ zone
->zone_start_pfn
;
56 page
= pfn_to_page(pfn
);
57 if (PageReserved(page
))
59 if (PageNosaveFree(page
))
70 struct highmem_page
*next
;
73 static struct highmem_page
*highmem_copy
;
75 static int save_highmem_zone(struct zone
*zone
)
77 unsigned long zone_pfn
;
78 mark_free_pages(zone
);
79 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
) {
81 struct highmem_page
*save
;
83 unsigned long pfn
= zone_pfn
+ zone
->zone_start_pfn
;
89 page
= pfn_to_page(pfn
);
91 * This condition results from rvmalloc() sans vmalloc_32()
92 * and architectural memory reservations. This should be
93 * corrected eventually when the cases giving rise to this
94 * are better understood.
96 if (PageReserved(page
))
98 BUG_ON(PageNosave(page
));
99 if (PageNosaveFree(page
))
101 save
= kmalloc(sizeof(struct highmem_page
), GFP_ATOMIC
);
104 save
->next
= highmem_copy
;
106 save
->data
= (void *) get_zeroed_page(GFP_ATOMIC
);
111 kaddr
= kmap_atomic(page
, KM_USER0
);
112 memcpy(save
->data
, kaddr
, PAGE_SIZE
);
113 kunmap_atomic(kaddr
, KM_USER0
);
119 int save_highmem(void)
124 pr_debug("swsusp: Saving Highmem\n");
125 for_each_zone (zone
) {
126 if (is_highmem(zone
))
127 res
= save_highmem_zone(zone
);
134 int restore_highmem(void)
136 printk("swsusp: Restoring Highmem\n");
137 while (highmem_copy
) {
138 struct highmem_page
*save
= highmem_copy
;
140 highmem_copy
= save
->next
;
142 kaddr
= kmap_atomic(save
->page
, KM_USER0
);
143 memcpy(kaddr
, save
->data
, PAGE_SIZE
);
144 kunmap_atomic(kaddr
, KM_USER0
);
145 free_page((long) save
->data
);
152 static int pfn_is_nosave(unsigned long pfn
)
154 unsigned long nosave_begin_pfn
= __pa(&__nosave_begin
) >> PAGE_SHIFT
;
155 unsigned long nosave_end_pfn
= PAGE_ALIGN(__pa(&__nosave_end
)) >> PAGE_SHIFT
;
156 return (pfn
>= nosave_begin_pfn
) && (pfn
< nosave_end_pfn
);
160 * saveable - Determine whether a page should be cloned or not.
163 * We save a page if it's Reserved, and not in the range of pages
164 * statically defined as 'unsaveable', or if it isn't reserved, and
165 * isn't part of a free chunk of pages.
168 static int saveable(struct zone
*zone
, unsigned long *zone_pfn
)
170 unsigned long pfn
= *zone_pfn
+ zone
->zone_start_pfn
;
176 page
= pfn_to_page(pfn
);
177 BUG_ON(PageReserved(page
) && PageNosave(page
));
178 if (PageNosave(page
))
180 if (PageReserved(page
) && pfn_is_nosave(pfn
))
182 if (PageNosaveFree(page
))
188 unsigned int count_data_pages(void)
191 unsigned long zone_pfn
;
194 for_each_zone (zone
) {
195 if (is_highmem(zone
))
197 mark_free_pages(zone
);
198 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
)
199 n
+= saveable(zone
, &zone_pfn
);
204 static void copy_data_pages(struct pbe
*pblist
)
207 unsigned long zone_pfn
;
211 for_each_zone (zone
) {
212 if (is_highmem(zone
))
214 mark_free_pages(zone
);
215 /* This is necessary for swsusp_free() */
216 for_each_pb_page (p
, pblist
)
217 SetPageNosaveFree(virt_to_page(p
));
218 for_each_pbe (p
, pblist
)
219 SetPageNosaveFree(virt_to_page(p
->address
));
220 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
) {
221 if (saveable(zone
, &zone_pfn
)) {
223 page
= pfn_to_page(zone_pfn
+ zone
->zone_start_pfn
);
225 pbe
->orig_address
= (unsigned long)page_address(page
);
226 /* copy_page is not usable for copying task structs. */
227 memcpy((void *)pbe
->address
, (void *)pbe
->orig_address
, PAGE_SIZE
);
237 * free_pagedir - free pages allocated with alloc_pagedir()
240 static void free_pagedir(struct pbe
*pblist
)
245 pbe
= (pblist
+ PB_PAGE_SKIP
)->next
;
246 ClearPageNosave(virt_to_page(pblist
));
247 ClearPageNosaveFree(virt_to_page(pblist
));
248 free_page((unsigned long)pblist
);
254 * fill_pb_page - Create a list of PBEs on a given memory page
257 static inline void fill_pb_page(struct pbe
*pbpage
)
262 pbpage
+= PB_PAGE_SKIP
;
265 while (++p
< pbpage
);
269 * create_pbe_list - Create a list of PBEs on top of a given chain
270 * of memory pages allocated with alloc_pagedir()
273 static inline void create_pbe_list(struct pbe
*pblist
, unsigned int nr_pages
)
275 struct pbe
*pbpage
, *p
;
276 unsigned int num
= PBES_PER_PAGE
;
278 for_each_pb_page (pbpage
, pblist
) {
282 fill_pb_page(pbpage
);
283 num
+= PBES_PER_PAGE
;
286 for (num
-= PBES_PER_PAGE
- 1, p
= pbpage
; num
< nr_pages
; p
++, num
++)
293 * On resume it is necessary to trace and eventually free the unsafe
294 * pages that have been allocated, because they are needed for I/O
295 * (on x86-64 we likely will "eat" these pages once again while
296 * creating the temporary page translation tables)
300 struct eaten_page
*next
;
301 char padding
[PAGE_SIZE
- sizeof(void *)];
304 static struct eaten_page
*eaten_pages
= NULL
;
306 static void release_eaten_pages(void)
308 struct eaten_page
*p
, *q
;
313 /* We don't want swsusp_free() to free this page again */
314 ClearPageNosave(virt_to_page(p
));
315 free_page((unsigned long)p
);
322 * @safe_needed - on resume, for storing the PBE list and the image,
323 * we can only use memory pages that do not conflict with the pages
324 * which had been used before suspend.
326 * The unsafe pages are marked with the PG_nosave_free flag
328 * Allocated but unusable (ie eaten) memory pages should be marked
329 * so that swsusp_free() can release them
332 static inline void *alloc_image_page(gfp_t gfp_mask
, int safe_needed
)
338 res
= (void *)get_zeroed_page(gfp_mask
);
339 if (res
&& PageNosaveFree(virt_to_page(res
))) {
340 /* This is for swsusp_free() */
341 SetPageNosave(virt_to_page(res
));
342 ((struct eaten_page
*)res
)->next
= eaten_pages
;
345 } while (res
&& PageNosaveFree(virt_to_page(res
)));
347 res
= (void *)get_zeroed_page(gfp_mask
);
349 SetPageNosave(virt_to_page(res
));
350 SetPageNosaveFree(virt_to_page(res
));
355 unsigned long get_safe_page(gfp_t gfp_mask
)
357 return (unsigned long)alloc_image_page(gfp_mask
, 1);
361 * alloc_pagedir - Allocate the page directory.
363 * First, determine exactly how many pages we need and
366 * We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
367 * struct pbe elements (pbes) and the last element in the page points
370 * On each page we set up a list of struct_pbe elements.
373 struct pbe
*alloc_pagedir(unsigned int nr_pages
, gfp_t gfp_mask
, int safe_needed
)
376 struct pbe
*pblist
, *pbe
;
381 pblist
= alloc_image_page(gfp_mask
, safe_needed
);
382 /* FIXME: rewrite this ugly loop */
383 for (pbe
= pblist
, num
= PBES_PER_PAGE
; pbe
&& num
< nr_pages
;
384 pbe
= pbe
->next
, num
+= PBES_PER_PAGE
) {
386 pbe
->next
= alloc_image_page(gfp_mask
, safe_needed
);
388 if (!pbe
) { /* get_zeroed_page() failed */
389 free_pagedir(pblist
);
392 create_pbe_list(pblist
, nr_pages
);
397 * Free pages we allocated for suspend. Suspend pages are alocated
398 * before atomic copy, so we need to free them after resume.
401 void swsusp_free(void)
404 unsigned long zone_pfn
;
406 for_each_zone(zone
) {
407 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
)
408 if (pfn_valid(zone_pfn
+ zone
->zone_start_pfn
)) {
410 page
= pfn_to_page(zone_pfn
+ zone
->zone_start_pfn
);
411 if (PageNosave(page
) && PageNosaveFree(page
)) {
412 ClearPageNosave(page
);
413 ClearPageNosaveFree(page
);
414 free_page((long) page_address(page
));
420 pagedir_nosave
= NULL
;
425 * enough_free_mem - Make sure we enough free memory to snapshot.
427 * Returns TRUE or FALSE after checking the number of available
431 static int enough_free_mem(unsigned int nr_pages
)
437 if (!is_highmem(zone
))
438 n
+= zone
->free_pages
;
439 pr_debug("swsusp: available memory: %u pages\n", n
);
440 return n
> (nr_pages
+ PAGES_FOR_IO
+
441 (nr_pages
+ PBES_PER_PAGE
- 1) / PBES_PER_PAGE
);
444 static int alloc_data_pages(struct pbe
*pblist
, gfp_t gfp_mask
, int safe_needed
)
448 for_each_pbe (p
, pblist
) {
449 p
->address
= (unsigned long)alloc_image_page(gfp_mask
, safe_needed
);
456 static struct pbe
*swsusp_alloc(unsigned int nr_pages
)
460 if (!(pblist
= alloc_pagedir(nr_pages
, GFP_ATOMIC
| __GFP_COLD
, 0))) {
461 printk(KERN_ERR
"suspend: Allocating pagedir failed.\n");
465 if (alloc_data_pages(pblist
, GFP_ATOMIC
| __GFP_COLD
, 0)) {
466 printk(KERN_ERR
"suspend: Allocating image pages failed.\n");
474 asmlinkage
int swsusp_save(void)
476 unsigned int nr_pages
;
478 pr_debug("swsusp: critical section: \n");
481 nr_pages
= count_data_pages();
482 printk("swsusp: Need to copy %u pages\n", nr_pages
);
484 pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
486 (nr_pages
+ PBES_PER_PAGE
- 1) / PBES_PER_PAGE
,
487 PAGES_FOR_IO
, nr_free_pages());
489 if (!enough_free_mem(nr_pages
)) {
490 printk(KERN_ERR
"swsusp: Not enough free memory\n");
494 pagedir_nosave
= swsusp_alloc(nr_pages
);
498 /* During allocating of suspend pagedir, new cold pages may appear.
502 copy_data_pages(pagedir_nosave
);
505 * End of critical section. From now on, we can write to memory,
506 * but we should not touch disk. This specially means we must _not_
507 * touch swap space! Except we must write out our image of course.
510 nr_copy_pages
= nr_pages
;
511 nr_meta_pages
= (nr_pages
* sizeof(long) + PAGE_SIZE
- 1) >> PAGE_SHIFT
;
513 printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages
);
517 static void init_header(struct swsusp_info
*info
)
519 memset(info
, 0, sizeof(struct swsusp_info
));
520 info
->version_code
= LINUX_VERSION_CODE
;
521 info
->num_physpages
= num_physpages
;
522 memcpy(&info
->uts
, &system_utsname
, sizeof(system_utsname
));
523 info
->cpus
= num_online_cpus();
524 info
->image_pages
= nr_copy_pages
;
525 info
->pages
= nr_copy_pages
+ nr_meta_pages
+ 1;
529 * pack_orig_addresses - the .orig_address fields of the PBEs from the
530 * list starting at @pbe are stored in the array @buf[] (1 page)
533 static inline struct pbe
*pack_orig_addresses(unsigned long *buf
, struct pbe
*pbe
)
537 for (j
= 0; j
< PAGE_SIZE
/ sizeof(long) && pbe
; j
++) {
538 buf
[j
] = pbe
->orig_address
;
542 for (; j
< PAGE_SIZE
/ sizeof(long); j
++)
548 * snapshot_read_next - used for reading the system memory snapshot.
550 * On the first call to it @handle should point to a zeroed
551 * snapshot_handle structure. The structure gets updated and a pointer
552 * to it should be passed to this function every next time.
554 * The @count parameter should contain the number of bytes the caller
555 * wants to read from the snapshot. It must not be zero.
557 * On success the function returns a positive number. Then, the caller
558 * is allowed to read up to the returned number of bytes from the memory
559 * location computed by the data_of() macro. The number returned
560 * may be smaller than @count, but this only happens if the read would
561 * cross a page boundary otherwise.
563 * The function returns 0 to indicate the end of data stream condition,
564 * and a negative number is returned on error. In such cases the
565 * structure pointed to by @handle is not updated and should not be used
569 int snapshot_read_next(struct snapshot_handle
*handle
, size_t count
)
571 static unsigned long *buffer
;
573 if (handle
->page
> nr_meta_pages
+ nr_copy_pages
)
576 /* This makes the buffer be freed by swsusp_free() */
577 buffer
= alloc_image_page(GFP_ATOMIC
, 0);
581 if (!handle
->offset
) {
582 init_header((struct swsusp_info
*)buffer
);
583 handle
->buffer
= buffer
;
584 handle
->pbe
= pagedir_nosave
;
586 if (handle
->prev
< handle
->page
) {
587 if (handle
->page
<= nr_meta_pages
) {
588 handle
->pbe
= pack_orig_addresses(buffer
, handle
->pbe
);
590 handle
->pbe
= pagedir_nosave
;
592 handle
->buffer
= (void *)handle
->pbe
->address
;
593 handle
->pbe
= handle
->pbe
->next
;
595 handle
->prev
= handle
->page
;
597 handle
->buf_offset
= handle
->page_offset
;
598 if (handle
->page_offset
+ count
>= PAGE_SIZE
) {
599 count
= PAGE_SIZE
- handle
->page_offset
;
600 handle
->page_offset
= 0;
603 handle
->page_offset
+= count
;
605 handle
->offset
+= count
;
610 * mark_unsafe_pages - mark the pages that cannot be used for storing
611 * the image during resume, because they conflict with the pages that
612 * had been used before suspend
615 static int mark_unsafe_pages(struct pbe
*pblist
)
618 unsigned long zone_pfn
;
621 if (!pblist
) /* a sanity check */
624 /* Clear page flags */
625 for_each_zone (zone
) {
626 for (zone_pfn
= 0; zone_pfn
< zone
->spanned_pages
; ++zone_pfn
)
627 if (pfn_valid(zone_pfn
+ zone
->zone_start_pfn
))
628 ClearPageNosaveFree(pfn_to_page(zone_pfn
+
629 zone
->zone_start_pfn
));
632 /* Mark orig addresses */
633 for_each_pbe (p
, pblist
) {
634 if (virt_addr_valid(p
->orig_address
))
635 SetPageNosaveFree(virt_to_page(p
->orig_address
));
643 static void copy_page_backup_list(struct pbe
*dst
, struct pbe
*src
)
645 /* We assume both lists contain the same number of elements */
647 dst
->orig_address
= src
->orig_address
;
653 static int check_header(struct swsusp_info
*info
)
657 if (info
->version_code
!= LINUX_VERSION_CODE
)
658 reason
= "kernel version";
659 if (info
->num_physpages
!= num_physpages
)
660 reason
= "memory size";
661 if (strcmp(info
->uts
.sysname
,system_utsname
.sysname
))
662 reason
= "system type";
663 if (strcmp(info
->uts
.release
,system_utsname
.release
))
664 reason
= "kernel release";
665 if (strcmp(info
->uts
.version
,system_utsname
.version
))
667 if (strcmp(info
->uts
.machine
,system_utsname
.machine
))
670 printk(KERN_ERR
"swsusp: Resume mismatch: %s\n", reason
);
677 * load header - check the image header and copy data from it
680 static int load_header(struct snapshot_handle
*handle
,
681 struct swsusp_info
*info
)
686 error
= check_header(info
);
688 pblist
= alloc_pagedir(info
->image_pages
, GFP_ATOMIC
, 0);
691 pagedir_nosave
= pblist
;
692 handle
->pbe
= pblist
;
693 nr_copy_pages
= info
->image_pages
;
694 nr_meta_pages
= info
->pages
- info
->image_pages
- 1;
700 * unpack_orig_addresses - copy the elements of @buf[] (1 page) to
701 * the PBEs in the list starting at @pbe
704 static inline struct pbe
*unpack_orig_addresses(unsigned long *buf
,
709 for (j
= 0; j
< PAGE_SIZE
/ sizeof(long) && pbe
; j
++) {
710 pbe
->orig_address
= buf
[j
];
717 * create_image - use metadata contained in the PBE list
718 * pointed to by pagedir_nosave to mark the pages that will
719 * be overwritten in the process of restoring the system
720 * memory state from the image and allocate memory for
721 * the image avoiding these pages
724 static int create_image(struct snapshot_handle
*handle
)
727 struct pbe
*p
, *pblist
;
730 error
= mark_unsafe_pages(p
);
732 pblist
= alloc_pagedir(nr_copy_pages
, GFP_ATOMIC
, 1);
734 copy_page_backup_list(pblist
, p
);
740 error
= alloc_data_pages(pblist
, GFP_ATOMIC
, 1);
742 release_eaten_pages();
743 pagedir_nosave
= pblist
;
745 pagedir_nosave
= NULL
;
754 * snapshot_write_next - used for writing the system memory snapshot.
756 * On the first call to it @handle should point to a zeroed
757 * snapshot_handle structure. The structure gets updated and a pointer
758 * to it should be passed to this function every next time.
760 * The @count parameter should contain the number of bytes the caller
761 * wants to write to the image. It must not be zero.
763 * On success the function returns a positive number. Then, the caller
764 * is allowed to write up to the returned number of bytes to the memory
765 * location computed by the data_of() macro. The number returned
766 * may be smaller than @count, but this only happens if the write would
767 * cross a page boundary otherwise.
769 * The function returns 0 to indicate the "end of file" condition,
770 * and a negative number is returned on error. In such cases the
771 * structure pointed to by @handle is not updated and should not be used
775 int snapshot_write_next(struct snapshot_handle
*handle
, size_t count
)
777 static unsigned long *buffer
;
780 if (handle
->prev
&& handle
->page
> nr_meta_pages
+ nr_copy_pages
)
783 /* This makes the buffer be freed by swsusp_free() */
784 buffer
= alloc_image_page(GFP_ATOMIC
, 0);
789 handle
->buffer
= buffer
;
790 if (handle
->prev
< handle
->page
) {
792 error
= load_header(handle
, (struct swsusp_info
*)buffer
);
795 } else if (handle
->prev
<= nr_meta_pages
) {
796 handle
->pbe
= unpack_orig_addresses(buffer
, handle
->pbe
);
798 error
= create_image(handle
);
801 handle
->pbe
= pagedir_nosave
;
802 handle
->buffer
= (void *)handle
->pbe
->address
;
805 handle
->pbe
= handle
->pbe
->next
;
806 handle
->buffer
= (void *)handle
->pbe
->address
;
808 handle
->prev
= handle
->page
;
810 handle
->buf_offset
= handle
->page_offset
;
811 if (handle
->page_offset
+ count
>= PAGE_SIZE
) {
812 count
= PAGE_SIZE
- handle
->page_offset
;
813 handle
->page_offset
= 0;
816 handle
->page_offset
+= count
;
818 handle
->offset
+= count
;
822 int snapshot_image_loaded(struct snapshot_handle
*handle
)
824 return !(!handle
->pbe
|| handle
->pbe
->next
|| !nr_copy_pages
||
825 handle
->page
<= nr_meta_pages
+ nr_copy_pages
);
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