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;
40 static unsigned long *buffer;
43 unsigned int count_highmem_pages(void)
46 unsigned long zone_pfn;
50 if (is_highmem(zone)) {
51 mark_free_pages(zone);
52 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; zone_pfn++) {
54 unsigned long pfn = zone_pfn + zone->zone_start_pfn;
57 page = pfn_to_page(pfn);
58 if (PageReserved(page))
60 if (PageNosaveFree(page))
71 struct highmem_page *next;
74 static struct highmem_page *highmem_copy;
76 static int save_highmem_zone(struct zone *zone)
78 unsigned long zone_pfn;
79 mark_free_pages(zone);
80 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
82 struct highmem_page *save;
84 unsigned long pfn = zone_pfn + zone->zone_start_pfn;
90 page = pfn_to_page(pfn);
92 * This condition results from rvmalloc() sans vmalloc_32()
93 * and architectural memory reservations. This should be
94 * corrected eventually when the cases giving rise to this
95 * are better understood.
97 if (PageReserved(page))
99 BUG_ON(PageNosave(page));
100 if (PageNosaveFree(page))
102 save = kmalloc(sizeof(struct highmem_page), GFP_ATOMIC);
105 save->next = highmem_copy;
107 save->data = (void *) get_zeroed_page(GFP_ATOMIC);
112 kaddr = kmap_atomic(page, KM_USER0);
113 memcpy(save->data, kaddr, PAGE_SIZE);
114 kunmap_atomic(kaddr, KM_USER0);
120 int save_highmem(void)
125 pr_debug("swsusp: Saving Highmem");
126 for_each_zone (zone) {
127 if (is_highmem(zone))
128 res = save_highmem_zone(zone);
136 int restore_highmem(void)
138 printk("swsusp: Restoring Highmem\n");
139 while (highmem_copy) {
140 struct highmem_page *save = highmem_copy;
142 highmem_copy = save->next;
144 kaddr = kmap_atomic(save->page, KM_USER0);
145 memcpy(kaddr, save->data, PAGE_SIZE);
146 kunmap_atomic(kaddr, KM_USER0);
147 free_page((long) save->data);
154 static int pfn_is_nosave(unsigned long pfn)
156 unsigned long nosave_begin_pfn = __pa(&__nosave_begin) >> PAGE_SHIFT;
157 unsigned long nosave_end_pfn = PAGE_ALIGN(__pa(&__nosave_end)) >> PAGE_SHIFT;
158 return (pfn >= nosave_begin_pfn) && (pfn < nosave_end_pfn);
162 * saveable - Determine whether a page should be cloned or not.
165 * We save a page if it's Reserved, and not in the range of pages
166 * statically defined as 'unsaveable', or if it isn't reserved, and
167 * isn't part of a free chunk of pages.
170 static int saveable(struct zone *zone, unsigned long *zone_pfn)
172 unsigned long pfn = *zone_pfn + zone->zone_start_pfn;
178 page = pfn_to_page(pfn);
179 BUG_ON(PageReserved(page) && PageNosave(page));
180 if (PageNosave(page))
182 if (PageReserved(page) && pfn_is_nosave(pfn))
184 if (PageNosaveFree(page))
190 unsigned int count_data_pages(void)
193 unsigned long zone_pfn;
196 for_each_zone (zone) {
197 if (is_highmem(zone))
199 mark_free_pages(zone);
200 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
201 n += saveable(zone, &zone_pfn);
206 static void copy_data_pages(struct pbe *pblist)
209 unsigned long zone_pfn;
213 for_each_zone (zone) {
214 if (is_highmem(zone))
216 mark_free_pages(zone);
217 /* This is necessary for swsusp_free() */
218 for_each_pb_page (p, pblist)
219 SetPageNosaveFree(virt_to_page(p));
220 for_each_pbe (p, pblist)
221 SetPageNosaveFree(virt_to_page(p->address));
222 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn) {
223 if (saveable(zone, &zone_pfn)) {
225 page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
227 pbe->orig_address = (unsigned long)page_address(page);
228 /* copy_page is not usable for copying task structs. */
229 memcpy((void *)pbe->address, (void *)pbe->orig_address, PAGE_SIZE);
239 * free_pagedir - free pages allocated with alloc_pagedir()
242 static void free_pagedir(struct pbe *pblist)
247 pbe = (pblist + PB_PAGE_SKIP)->next;
248 ClearPageNosave(virt_to_page(pblist));
249 ClearPageNosaveFree(virt_to_page(pblist));
250 free_page((unsigned long)pblist);
256 * fill_pb_page - Create a list of PBEs on a given memory page
259 static inline void fill_pb_page(struct pbe *pbpage)
264 pbpage += PB_PAGE_SKIP;
267 while (++p < pbpage);
271 * create_pbe_list - Create a list of PBEs on top of a given chain
272 * of memory pages allocated with alloc_pagedir()
275 static inline void create_pbe_list(struct pbe *pblist, unsigned int nr_pages)
277 struct pbe *pbpage, *p;
278 unsigned int num = PBES_PER_PAGE;
280 for_each_pb_page (pbpage, pblist) {
284 fill_pb_page(pbpage);
285 num += PBES_PER_PAGE;
288 for (num -= PBES_PER_PAGE - 1, p = pbpage; num < nr_pages; p++, num++)
295 * On resume it is necessary to trace and eventually free the unsafe
296 * pages that have been allocated, because they are needed for I/O
297 * (on x86-64 we likely will "eat" these pages once again while
298 * creating the temporary page translation tables)
302 struct eaten_page *next;
303 char padding[PAGE_SIZE - sizeof(void *)];
306 static struct eaten_page *eaten_pages = NULL;
308 static void release_eaten_pages(void)
310 struct eaten_page *p, *q;
315 /* We don't want swsusp_free() to free this page again */
316 ClearPageNosave(virt_to_page(p));
317 free_page((unsigned long)p);
324 * @safe_needed - on resume, for storing the PBE list and the image,
325 * we can only use memory pages that do not conflict with the pages
326 * which had been used before suspend.
328 * The unsafe pages are marked with the PG_nosave_free flag
330 * Allocated but unusable (ie eaten) memory pages should be marked
331 * so that swsusp_free() can release them
334 static inline void *alloc_image_page(gfp_t gfp_mask, int safe_needed)
340 res = (void *)get_zeroed_page(gfp_mask);
341 if (res && PageNosaveFree(virt_to_page(res))) {
342 /* This is for swsusp_free() */
343 SetPageNosave(virt_to_page(res));
344 ((struct eaten_page *)res)->next = eaten_pages;
347 } while (res && PageNosaveFree(virt_to_page(res)));
349 res = (void *)get_zeroed_page(gfp_mask);
351 SetPageNosave(virt_to_page(res));
352 SetPageNosaveFree(virt_to_page(res));
357 unsigned long get_safe_page(gfp_t gfp_mask)
359 return (unsigned long)alloc_image_page(gfp_mask, 1);
363 * alloc_pagedir - Allocate the page directory.
365 * First, determine exactly how many pages we need and
368 * We arrange the pages in a chain: each page is an array of PBES_PER_PAGE
369 * struct pbe elements (pbes) and the last element in the page points
372 * On each page we set up a list of struct_pbe elements.
375 struct pbe *alloc_pagedir(unsigned int nr_pages, gfp_t gfp_mask, int safe_needed)
378 struct pbe *pblist, *pbe;
383 pblist = alloc_image_page(gfp_mask, safe_needed);
384 /* FIXME: rewrite this ugly loop */
385 for (pbe = pblist, num = PBES_PER_PAGE; pbe && num < nr_pages;
386 pbe = pbe->next, num += PBES_PER_PAGE) {
388 pbe->next = alloc_image_page(gfp_mask, safe_needed);
390 if (!pbe) { /* get_zeroed_page() failed */
391 free_pagedir(pblist);
394 create_pbe_list(pblist, nr_pages);
399 * Free pages we allocated for suspend. Suspend pages are alocated
400 * before atomic copy, so we need to free them after resume.
403 void swsusp_free(void)
406 unsigned long zone_pfn;
408 for_each_zone(zone) {
409 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
410 if (pfn_valid(zone_pfn + zone->zone_start_pfn)) {
412 page = pfn_to_page(zone_pfn + zone->zone_start_pfn);
413 if (PageNosave(page) && PageNosaveFree(page)) {
414 ClearPageNosave(page);
415 ClearPageNosaveFree(page);
416 free_page((long) page_address(page));
422 pagedir_nosave = NULL;
428 * enough_free_mem - Make sure we enough free memory to snapshot.
430 * Returns TRUE or FALSE after checking the number of available
434 static int enough_free_mem(unsigned int nr_pages)
440 if (!is_highmem(zone))
441 n += zone->free_pages;
442 pr_debug("swsusp: available memory: %u pages\n", n);
443 return n > (nr_pages + PAGES_FOR_IO +
444 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE);
447 static int alloc_data_pages(struct pbe *pblist, gfp_t gfp_mask, int safe_needed)
451 for_each_pbe (p, pblist) {
452 p->address = (unsigned long)alloc_image_page(gfp_mask, safe_needed);
459 static struct pbe *swsusp_alloc(unsigned int nr_pages)
463 if (!(pblist = alloc_pagedir(nr_pages, GFP_ATOMIC | __GFP_COLD, 0))) {
464 printk(KERN_ERR "suspend: Allocating pagedir failed.\n");
468 if (alloc_data_pages(pblist, GFP_ATOMIC | __GFP_COLD, 0)) {
469 printk(KERN_ERR "suspend: Allocating image pages failed.\n");
477 asmlinkage int swsusp_save(void)
479 unsigned int nr_pages;
481 pr_debug("swsusp: critical section: \n");
484 nr_pages = count_data_pages();
485 printk("swsusp: Need to copy %u pages\n", nr_pages);
487 pr_debug("swsusp: pages needed: %u + %lu + %u, free: %u\n",
489 (nr_pages + PBES_PER_PAGE - 1) / PBES_PER_PAGE,
490 PAGES_FOR_IO, nr_free_pages());
492 if (!enough_free_mem(nr_pages)) {
493 printk(KERN_ERR "swsusp: Not enough free memory\n");
497 pagedir_nosave = swsusp_alloc(nr_pages);
501 /* During allocating of suspend pagedir, new cold pages may appear.
505 copy_data_pages(pagedir_nosave);
508 * End of critical section. From now on, we can write to memory,
509 * but we should not touch disk. This specially means we must _not_
510 * touch swap space! Except we must write out our image of course.
513 nr_copy_pages = nr_pages;
514 nr_meta_pages = (nr_pages * sizeof(long) + PAGE_SIZE - 1) >> PAGE_SHIFT;
516 printk("swsusp: critical section/: done (%d pages copied)\n", nr_pages);
520 static void init_header(struct swsusp_info *info)
522 memset(info, 0, sizeof(struct swsusp_info));
523 info->version_code = LINUX_VERSION_CODE;
524 info->num_physpages = num_physpages;
525 memcpy(&info->uts, &system_utsname, sizeof(system_utsname));
526 info->cpus = num_online_cpus();
527 info->image_pages = nr_copy_pages;
528 info->pages = nr_copy_pages + nr_meta_pages + 1;
529 info->size = info->pages;
530 info->size <<= PAGE_SHIFT;
534 * pack_orig_addresses - the .orig_address fields of the PBEs from the
535 * list starting at @pbe are stored in the array @buf[] (1 page)
538 static inline struct pbe *pack_orig_addresses(unsigned long *buf, struct pbe *pbe)
542 for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
543 buf[j] = pbe->orig_address;
547 for (; j < PAGE_SIZE / sizeof(long); j++)
553 * snapshot_read_next - used for reading the system memory snapshot.
555 * On the first call to it @handle should point to a zeroed
556 * snapshot_handle structure. The structure gets updated and a pointer
557 * to it should be passed to this function every next time.
559 * The @count parameter should contain the number of bytes the caller
560 * wants to read from the snapshot. It must not be zero.
562 * On success the function returns a positive number. Then, the caller
563 * is allowed to read up to the returned number of bytes from the memory
564 * location computed by the data_of() macro. The number returned
565 * may be smaller than @count, but this only happens if the read would
566 * cross a page boundary otherwise.
568 * The function returns 0 to indicate the end of data stream condition,
569 * and a negative number is returned on error. In such cases the
570 * structure pointed to by @handle is not updated and should not be used
574 int snapshot_read_next(struct snapshot_handle *handle, size_t count)
576 if (handle->page > nr_meta_pages + nr_copy_pages)
579 /* This makes the buffer be freed by swsusp_free() */
580 buffer = alloc_image_page(GFP_ATOMIC, 0);
584 if (!handle->offset) {
585 init_header((struct swsusp_info *)buffer);
586 handle->buffer = buffer;
587 handle->pbe = pagedir_nosave;
589 if (handle->prev < handle->page) {
590 if (handle->page <= nr_meta_pages) {
591 handle->pbe = pack_orig_addresses(buffer, handle->pbe);
593 handle->pbe = pagedir_nosave;
595 handle->buffer = (void *)handle->pbe->address;
596 handle->pbe = handle->pbe->next;
598 handle->prev = handle->page;
600 handle->buf_offset = handle->page_offset;
601 if (handle->page_offset + count >= PAGE_SIZE) {
602 count = PAGE_SIZE - handle->page_offset;
603 handle->page_offset = 0;
606 handle->page_offset += count;
608 handle->offset += count;
613 * mark_unsafe_pages - mark the pages that cannot be used for storing
614 * the image during resume, because they conflict with the pages that
615 * had been used before suspend
618 static int mark_unsafe_pages(struct pbe *pblist)
621 unsigned long zone_pfn;
624 if (!pblist) /* a sanity check */
627 /* Clear page flags */
628 for_each_zone (zone) {
629 for (zone_pfn = 0; zone_pfn < zone->spanned_pages; ++zone_pfn)
630 if (pfn_valid(zone_pfn + zone->zone_start_pfn))
631 ClearPageNosaveFree(pfn_to_page(zone_pfn +
632 zone->zone_start_pfn));
635 /* Mark orig addresses */
636 for_each_pbe (p, pblist) {
637 if (virt_addr_valid(p->orig_address))
638 SetPageNosaveFree(virt_to_page(p->orig_address));
646 static void copy_page_backup_list(struct pbe *dst, struct pbe *src)
648 /* We assume both lists contain the same number of elements */
650 dst->orig_address = src->orig_address;
656 static int check_header(struct swsusp_info *info)
660 if (info->version_code != LINUX_VERSION_CODE)
661 reason = "kernel version";
662 if (info->num_physpages != num_physpages)
663 reason = "memory size";
664 if (strcmp(info->uts.sysname,system_utsname.sysname))
665 reason = "system type";
666 if (strcmp(info->uts.release,system_utsname.release))
667 reason = "kernel release";
668 if (strcmp(info->uts.version,system_utsname.version))
670 if (strcmp(info->uts.machine,system_utsname.machine))
673 printk(KERN_ERR "swsusp: Resume mismatch: %s\n", reason);
680 * load header - check the image header and copy data from it
683 static int load_header(struct snapshot_handle *handle,
684 struct swsusp_info *info)
689 error = check_header(info);
691 pblist = alloc_pagedir(info->image_pages, GFP_ATOMIC, 0);
694 pagedir_nosave = pblist;
695 handle->pbe = pblist;
696 nr_copy_pages = info->image_pages;
697 nr_meta_pages = info->pages - info->image_pages - 1;
703 * unpack_orig_addresses - copy the elements of @buf[] (1 page) to
704 * the PBEs in the list starting at @pbe
707 static inline struct pbe *unpack_orig_addresses(unsigned long *buf,
712 for (j = 0; j < PAGE_SIZE / sizeof(long) && pbe; j++) {
713 pbe->orig_address = buf[j];
720 * create_image - use metadata contained in the PBE list
721 * pointed to by pagedir_nosave to mark the pages that will
722 * be overwritten in the process of restoring the system
723 * memory state from the image and allocate memory for
724 * the image avoiding these pages
727 static int create_image(struct snapshot_handle *handle)
730 struct pbe *p, *pblist;
733 error = mark_unsafe_pages(p);
735 pblist = alloc_pagedir(nr_copy_pages, GFP_ATOMIC, 1);
737 copy_page_backup_list(pblist, p);
743 error = alloc_data_pages(pblist, GFP_ATOMIC, 1);
745 release_eaten_pages();
746 pagedir_nosave = pblist;
748 pagedir_nosave = NULL;
757 * snapshot_write_next - used for writing the system memory snapshot.
759 * On the first call to it @handle should point to a zeroed
760 * snapshot_handle structure. The structure gets updated and a pointer
761 * to it should be passed to this function every next time.
763 * The @count parameter should contain the number of bytes the caller
764 * wants to write to the image. It must not be zero.
766 * On success the function returns a positive number. Then, the caller
767 * is allowed to write up to the returned number of bytes to the memory
768 * location computed by the data_of() macro. The number returned
769 * may be smaller than @count, but this only happens if the write would
770 * cross a page boundary otherwise.
772 * The function returns 0 to indicate the "end of file" condition,
773 * and a negative number is returned on error. In such cases the
774 * structure pointed to by @handle is not updated and should not be used
778 int snapshot_write_next(struct snapshot_handle *handle, size_t count)
782 if (handle->prev && handle->page > nr_meta_pages + nr_copy_pages)
785 /* This makes the buffer be freed by swsusp_free() */
786 buffer = alloc_image_page(GFP_ATOMIC, 0);
791 handle->buffer = buffer;
792 if (handle->prev < handle->page) {
794 error = load_header(handle, (struct swsusp_info *)buffer);
797 } else if (handle->prev <= nr_meta_pages) {
798 handle->pbe = unpack_orig_addresses(buffer, handle->pbe);
800 error = create_image(handle);
803 handle->pbe = pagedir_nosave;
804 handle->buffer = (void *)handle->pbe->address;
807 handle->pbe = handle->pbe->next;
808 handle->buffer = (void *)handle->pbe->address;
810 handle->prev = handle->page;
812 handle->buf_offset = handle->page_offset;
813 if (handle->page_offset + count >= PAGE_SIZE) {
814 count = PAGE_SIZE - handle->page_offset;
815 handle->page_offset = 0;
818 handle->page_offset += count;
820 handle->offset += count;
824 int snapshot_image_loaded(struct snapshot_handle *handle)
826 return !(!handle->pbe || handle->pbe->next || !nr_copy_pages ||
827 handle->page <= nr_meta_pages + nr_copy_pages);