3 files changed, 324 insertions, 174 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index c9d7408..096fe48 100644
--- a/kernel/power/disk.c
+++ b/kernel/power/disk.c
@@ -259,12 +259,12 @@ int hibernation_snapshot(int platform_mode)
 {
 	int error, ftrace_save;
 
-	/* Free memory before shutting down devices. */
-	error = swsusp_shrink_memory();
+	error = platform_begin(platform_mode);
 	if (error)
 		return error;
 
-	error = platform_begin(platform_mode);
+	/* Free memory before shutting down devices. */
+	error = swsusp_shrink_memory();
 	if (error)
 		goto Close;
 
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 5d2ab83..f5fc2d7 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -25,6 +25,7 @@
 #include <linux/syscalls.h>
 #include <linux/console.h>
 #include <linux/highmem.h>
+#include <linux/list.h>
 
 #include <asm/uaccess.h>
 #include <asm/mmu_context.h>
@@ -192,12 +193,6 @@ static void *chain_alloc(struct chain_allocator *ca, unsigned int size)
 	return ret;
 }
 
-static void chain_free(struct chain_allocator *ca, int clear_page_nosave)
-{
-	free_list_of_pages(ca->chain, clear_page_nosave);
-	memset(ca, 0, sizeof(struct chain_allocator));
-}
-
 /**
  *	Data types related to memory bitmaps.
  *
@@ -233,7 +228,7 @@ static void chain_free(struct chain_allocator *ca, int clear_page_nosave)
 #define BM_BITS_PER_BLOCK	(PAGE_SIZE << 3)
 
 struct bm_block {
-	struct bm_block *next;		/* next element of the list */
+	struct list_head hook;	/* hook into a list of bitmap blocks */
 	unsigned long start_pfn;	/* pfn represented by the first bit */
 	unsigned long end_pfn;	/* pfn represented by the last bit plus 1 */
 	unsigned long *data;	/* bitmap representing pages */
@@ -244,24 +239,15 @@ static inline unsigned long bm_block_bits(struct bm_block *bb)
 	return bb->end_pfn - bb->start_pfn;
 }
 
-struct zone_bitmap {
-	struct zone_bitmap *next;	/* next element of the list */
-	unsigned long start_pfn;	/* minimal pfn in this zone */
-	unsigned long end_pfn;		/* maximal pfn in this zone plus 1 */
-	struct bm_block *bm_blocks;	/* list of bitmap blocks */
-	struct bm_block *cur_block;	/* recently used bitmap block */
-};
-
 /* strcut bm_position is used for browsing memory bitmaps */
 
 struct bm_position {
-	struct zone_bitmap *zone_bm;
 	struct bm_block *block;
 	int bit;
 };
 
 struct memory_bitmap {
-	struct zone_bitmap *zone_bm_list;	/* list of zone bitmaps */
+	struct list_head blocks;	/* list of bitmap blocks */
 	struct linked_page *p_list;	/* list of pages used to store zone
 					 * bitmap objects and bitmap block
 					 * objects
@@ -273,11 +259,7 @@ struct memory_bitmap {
 
 static void memory_bm_position_reset(struct memory_bitmap *bm)
 {
-	struct zone_bitmap *zone_bm;
-
-	zone_bm = bm->zone_bm_list;
-	bm->cur.zone_bm = zone_bm;
-	bm->cur.block = zone_bm->bm_blocks;
+	bm->cur.block = list_entry(bm->blocks.next, struct bm_block, hook);
 	bm->cur.bit = 0;
 }
 
@@ -285,151 +267,184 @@ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free);
 
 /**
  *	create_bm_block_list - create a list of block bitmap objects
+ *	@nr_blocks - number of blocks to allocate
+ *	@list - list to put the allocated blocks into
+ *	@ca - chain allocator to be used for allocating memory
  */
-
-static inline struct bm_block *
-create_bm_block_list(unsigned int nr_blocks, struct chain_allocator *ca)
+static int create_bm_block_list(unsigned long pages,
+				struct list_head *list,
+				struct chain_allocator *ca)
 {
-	struct bm_block *bblist = NULL;
+	unsigned int nr_blocks = DIV_ROUND_UP(pages, BM_BITS_PER_BLOCK);
 
 	while (nr_blocks-- > 0) {
 		struct bm_block *bb;
 
 		bb = chain_alloc(ca, sizeof(struct bm_block));
 		if (!bb)
-			return NULL;
-
-		bb->next = bblist;
-		bblist = bb;
+			return -ENOMEM;
+		list_add(&bb->hook, list);
 	}
-	return bblist;
+
+	return 0;
 }
 
+struct mem_extent {
+	struct list_head hook;
+	unsigned long start;
+	unsigned long end;
+};
+
 /**
- *	create_zone_bm_list - create a list of zone bitmap objects
+ *	free_mem_extents - free a list of memory extents
+ *	@list - list of extents to empty
  */
+static void free_mem_extents(struct list_head *list)
+{
+	struct mem_extent *ext, *aux;
 
-static inline struct zone_bitmap *
-create_zone_bm_list(unsigned int nr_zones, struct chain_allocator *ca)
+	list_for_each_entry_safe(ext, aux, list, hook) {
+		list_del(&ext->hook);
+		kfree(ext);
+	}
+}
+
+/**
+ *	create_mem_extents - create a list of memory extents representing
+ *	                     contiguous ranges of PFNs
+ *	@list - list to put the extents into
+ *	@gfp_mask - mask to use for memory allocations
+ */
+static int create_mem_extents(struct list_head *list, gfp_t gfp_mask)
 {
-	struct zone_bitmap *zbmlist = NULL;
+	struct zone *zone;
 
-	while (nr_zones-- > 0) {
-		struct zone_bitmap *zbm;
+	INIT_LIST_HEAD(list);
 
-		zbm = chain_alloc(ca, sizeof(struct zone_bitmap));
-		if (!zbm)
-			return NULL;
+	for_each_zone(zone) {
+		unsigned long zone_start, zone_end;
+		struct mem_extent *ext, *cur, *aux;
+
+		if (!populated_zone(zone))
+			continue;
 
-		zbm->next = zbmlist;
-		zbmlist = zbm;
+		zone_start = zone->zone_start_pfn;
+		zone_end = zone->zone_start_pfn + zone->spanned_pages;
+
+		list_for_each_entry(ext, list, hook)
+			if (zone_start <= ext->end)
+				break;
+
+		if (&ext->hook == list || zone_end < ext->start) {
+			/* New extent is necessary */
+			struct mem_extent *new_ext;
+
+			new_ext = kzalloc(sizeof(struct mem_extent), gfp_mask);
+			if (!new_ext) {
+				free_mem_extents(list);
+				return -ENOMEM;
+			}
+			new_ext->start = zone_start;
+			new_ext->end = zone_end;
+			list_add_tail(&new_ext->hook, &ext->hook);
+			continue;
+		}
+
+		/* Merge this zone's range of PFNs with the existing one */
+		if (zone_start < ext->start)
+			ext->start = zone_start;
+		if (zone_end > ext->end)
+			ext->end = zone_end;
+
+		/* More merging may be possible */
+		cur = ext;
+		list_for_each_entry_safe_continue(cur, aux, list, hook) {
+			if (zone_end < cur->start)
+				break;
+			if (zone_end < cur->end)
+				ext->end = cur->end;
+			list_del(&cur->hook);
+			kfree(cur);
+		}
 	}
-	return zbmlist;
+
+	return 0;
 }
 
 /**
   *	memory_bm_create - allocate memory for a memory bitmap
   */
-
 static int
 memory_bm_create(struct memory_bitmap *bm, gfp_t gfp_mask, int safe_needed)
 {
 	struct chain_allocator ca;
-	struct zone *zone;
-	struct zone_bitmap *zone_bm;
-	struct bm_block *bb;
-	unsigned int nr;
+	struct list_head mem_extents;
+	struct mem_extent *ext;
+	int error;
 
 	chain_init(&ca, gfp_mask, safe_needed);
+	INIT_LIST_HEAD(&bm->blocks);
 
-	/* Compute the number of zones */
-	nr = 0;
-	for_each_zone(zone)
-		if (populated_zone(zone))
-			nr++;
-
-	/* Allocate the list of zones bitmap objects */
-	zone_bm = create_zone_bm_list(nr, &ca);
-	bm->zone_bm_list = zone_bm;
-	if (!zone_bm) {
-		chain_free(&ca, PG_UNSAFE_CLEAR);
-		return -ENOMEM;
-	}
-
-	/* Initialize the zone bitmap objects */
-	for_each_zone(zone) {
-		unsigned long pfn;
+	error = create_mem_extents(&mem_extents, gfp_mask);
+	if (error)
+		return error;
 
-		if (!populated_zone(zone))
-			continue;
+	list_for_each_entry(ext, &mem_extents, hook) {
+		struct bm_block *bb;
+		unsigned long pfn = ext->start;
+		unsigned long pages = ext->end - ext->start;
 
-		zone_bm->start_pfn = zone->zone_start_pfn;
-		zone_bm->end_pfn = zone->zone_start_pfn + zone->spanned_pages;
-		/* Allocate the list of bitmap block objects */
-		nr = DIV_ROUND_UP(zone->spanned_pages, BM_BITS_PER_BLOCK);
-		bb = create_bm_block_list(nr, &ca);
-		zone_bm->bm_blocks = bb;
-		zone_bm->cur_block = bb;
-		if (!bb)
-			goto Free;
+		bb = list_entry(bm->blocks.prev, struct bm_block, hook);
 
-		nr = zone->spanned_pages;
-		pfn = zone->zone_start_pfn;
-		/* Initialize the bitmap block objects */
-		while (bb) {
-			unsigned long *ptr;
+		error = create_bm_block_list(pages, bm->blocks.prev, &ca);
+		if (error)
+			goto Error;
 
-			ptr = get_image_page(gfp_mask, safe_needed);
-			bb->data = ptr;
-			if (!ptr)
-				goto Free;
+		list_for_each_entry_continue(bb, &bm->blocks, hook) {
+			bb->data = get_image_page(gfp_mask, safe_needed);
+			if (!bb->data) {
+				error = -ENOMEM;
+				goto Error;
+			}
 
 			bb->start_pfn = pfn;
-			if (nr >= BM_BITS_PER_BLOCK) {
+			if (pages >= BM_BITS_PER_BLOCK) {
 				pfn += BM_BITS_PER_BLOCK;
-				nr -= BM_BITS_PER_BLOCK;
+				pages -= BM_BITS_PER_BLOCK;
 			} else {
 				/* This is executed only once in the loop */
-				pfn += nr;
+				pfn += pages;
 			}
 			bb->end_pfn = pfn;
-			bb = bb->next;
 		}
-		zone_bm = zone_bm->next;
 	}
+
 	bm->p_list = ca.chain;
 	memory_bm_position_reset(bm);
-	return 0;
+ Exit:
+	free_mem_extents(&mem_extents);
+	return error;
 
- Free:
+ Error:
 	bm->p_list = ca.chain;
 	memory_bm_free(bm, PG_UNSAFE_CLEAR);
-	return -ENOMEM;
+	goto Exit;
 }
 
 /**
   *	memory_bm_free - free memory occupied by the memory bitmap @bm
   */
-
 static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
 {
-	struct zone_bitmap *zone_bm;
+	struct bm_block *bb;
 
-	/* Free the list of bit blocks for each zone_bitmap object */
-	zone_bm = bm->zone_bm_list;
-	while (zone_bm) {
-		struct bm_block *bb;
+	list_for_each_entry(bb, &bm->blocks, hook)
+		if (bb->data)
+			free_image_page(bb->data, clear_nosave_free);
 
-		bb = zone_bm->bm_blocks;
-		while (bb) {
-			if (bb->data)
-				free_image_page(bb->data, clear_nosave_free);
-			bb = bb->next;
-		}
-		zone_bm = zone_bm->next;
-	}
 	free_list_of_pages(bm->p_list, clear_nosave_free);
-	bm->zone_bm_list = NULL;
+
+	INIT_LIST_HEAD(&bm->blocks);
 }
 
 /**
@@ -437,38 +452,33 @@ static void memory_bm_free(struct memory_bitmap *bm, int clear_nosave_free)
  *	to given pfn.  The cur_zone_bm member of @bm and the cur_block member
  *	of @bm->cur_zone_bm are updated.
  */
-
 static int memory_bm_find_bit(struct memory_bitmap *bm, unsigned long pfn,
 				void **addr, unsigned int *bit_nr)
 {
-	struct zone_bitmap *zone_bm;
 	struct bm_block *bb;
 
-	/* Check if the pfn is from the current zone */
-	zone_bm = bm->cur.zone_bm;
-	if (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
-		zone_bm = bm->zone_bm_list;
-		/* We don't assume that the zones are sorted by pfns */
-		while (pfn < zone_bm->start_pfn || pfn >= zone_bm->end_pfn) {
-			zone_bm = zone_bm->next;
-
-			if (!zone_bm)
-				return -EFAULT;
-		}
-		bm->cur.zone_bm = zone_bm;
-	}
-	/* Check if the pfn corresponds to the current bitmap block */
-	bb = zone_bm->cur_block;
+	/*
+	 * Check if the pfn corresponds to the current bitmap block and find
+	 * the block where it fits if this is not the case.
+	 */
+	bb = bm->cur.block;
 	if (pfn < bb->start_pfn)
-		bb = zone_bm->bm_blocks;
+		list_for_each_entry_continue_reverse(bb, &bm->blocks, hook)
+			if (pfn >= bb->start_pfn)
+				break;
 
-	while (pfn >= bb->end_pfn) {
-		bb = bb->next;
+	if (pfn >= bb->end_pfn)
+		list_for_each_entry_continue(bb, &bm->blocks, hook)
+			if (pfn >= bb->start_pfn && pfn < bb->end_pfn)
+				break;
 
-		BUG_ON(!bb);
-	}
-	zone_bm->cur_block = bb;
+	if (&bb->hook == &bm->blocks)
+		return -EFAULT;
+
+	/* The block has been found */
+	bm->cur.block = bb;
 	pfn -= bb->start_pfn;
+	bm->cur.bit = pfn + 1;
 	*bit_nr = pfn;
 	*addr = bb->data;
 	return 0;
@@ -519,6 +529,14 @@ static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
 	return test_bit(bit, addr);
 }
 
+static bool memory_bm_pfn_present(struct memory_bitmap *bm, unsigned long pfn)
+{
+	void *addr;
+	unsigned int bit;
+
+	return !memory_bm_find_bit(bm, pfn, &addr, &bit);
+}
+
 /**
  *	memory_bm_next_pfn - find the pfn that corresponds to the next set bit
  *	in the bitmap @bm.  If the pfn cannot be found, BM_END_OF_MAP is
@@ -530,29 +548,21 @@ static int memory_bm_test_bit(struct memory_bitmap *bm, unsigned long pfn)
 
 static unsigned long memory_bm_next_pfn(struct memory_bitmap *bm)
 {
-	struct zone_bitmap *zone_bm;
 	struct bm_block *bb;
 	int bit;
 
+	bb = bm->cur.block;
 	do {
-		bb = bm->cur.block;
-		do {
-			bit = bm->cur.bit;
-			bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
-			if (bit < bm_block_bits(bb))
-				goto Return_pfn;
-
-			bb = bb->next;
-			bm->cur.block = bb;
-			bm->cur.bit = 0;
-		} while (bb);
-		zone_bm = bm->cur.zone_bm->next;
-		if (zone_bm) {
-			bm->cur.zone_bm = zone_bm;
-			bm->cur.block = zone_bm->bm_blocks;
-			bm->cur.bit = 0;
-		}
-	} while (zone_bm);
+		bit = bm->cur.bit;
+		bit = find_next_bit(bb->data, bm_block_bits(bb), bit);
+		if (bit < bm_block_bits(bb))
+			goto Return_pfn;
+
+		bb = list_entry(bb->hook.next, struct bm_block, hook);
+		bm->cur.block = bb;
+		bm->cur.bit = 0;
+	} while (&bb->hook != &bm->blocks);
+
 	memory_bm_position_reset(bm);
 	return BM_END_OF_MAP;
 
@@ -808,8 +818,7 @@ static unsigned int count_free_highmem_pages(void)
  *	We should save the page if it isn't Nosave or NosaveFree, or Reserved,
  *	and it isn't a part of a free chunk of pages.
  */
-
-static struct page *saveable_highmem_page(unsigned long pfn)
+static struct page *saveable_highmem_page(struct zone *zone, unsigned long pfn)
 {
 	struct page *page;
 
@@ -817,6 +826,8 @@ static struct page *saveable_highmem_page(unsigned long pfn)
 		return NULL;
 
 	page = pfn_to_page(pfn);
+	if (page_zone(page) != zone)
+		return NULL;
 
 	BUG_ON(!PageHighMem(page));
 
@@ -846,13 +857,16 @@ unsigned int count_highmem_pages(void)
 		mark_free_pages(zone);
 		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
-			if (saveable_highmem_page(pfn))
+			if (saveable_highmem_page(zone, pfn))
 				n++;
 	}
 	return n;
 }
 #else
-static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
+static inline void *saveable_highmem_page(struct zone *z, unsigned long p)
+{
+	return NULL;
+}
 #endif /* CONFIG_HIGHMEM */
 
 /**
@@ -863,8 +877,7 @@ static inline void *saveable_highmem_page(unsigned long pfn) { return NULL; }
  *	of pages statically defined as 'unsaveable', and it isn't a part of
  *	a free chunk of pages.
  */
-
-static struct page *saveable_page(unsigned long pfn)
+static struct page *saveable_page(struct zone *zone, unsigned long pfn)
 {
 	struct page *page;
 
@@ -872,6 +885,8 @@ static struct page *saveable_page(unsigned long pfn)
 		return NULL;
 
 	page = pfn_to_page(pfn);
+	if (page_zone(page) != zone)
+		return NULL;
 
 	BUG_ON(PageHighMem(page));
 
@@ -903,7 +918,7 @@ unsigned int count_data_pages(void)
 		mark_free_pages(zone);
 		max_zone_pfn = zone->zone_start_pfn + zone->spanned_pages;
 		for (pfn = zone->zone_start_pfn; pfn < max_zone_pfn; pfn++)
-			if(saveable_page(pfn))
+			if (saveable_page(zone, pfn))
 				n++;
 	}
 	return n;
@@ -944,7 +959,7 @@ static inline struct page *
 page_is_saveable(struct zone *zone, unsigned long pfn)
 {
 	return is_highmem(zone) ?
-			saveable_highmem_page(pfn) : saveable_page(pfn);
+		saveable_highmem_page(zone, pfn) : saveable_page(zone, pfn);
 }
 
 static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
@@ -966,7 +981,7 @@ static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 			 * data modified by kmap_atomic()
 			 */
 			safe_copy_page(buffer, s_page);
-			dst = kmap_atomic(pfn_to_page(dst_pfn), KM_USER0);
+			dst = kmap_atomic(d_page, KM_USER0);
 			memcpy(dst, buffer, PAGE_SIZE);
 			kunmap_atomic(dst, KM_USER0);
 		} else {
@@ -975,7 +990,7 @@ static void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 	}
 }
 #else
-#define page_is_saveable(zone, pfn)	saveable_page(pfn)
+#define page_is_saveable(zone, pfn)	saveable_page(zone, pfn)
 
 static inline void copy_data_page(unsigned long dst_pfn, unsigned long src_pfn)
 {
@@ -1459,9 +1474,7 @@ load_header(struct swsusp_info *info)
  *	unpack_orig_pfns - for each element of @buf[] (1 page at a time) set
  *	the corresponding bit in the memory bitmap @bm
  */
-
-static inline void
-unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
+static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
 {
 	int j;
 
@@ -1469,8 +1482,13 @@ unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
 		if (unlikely(buf[j] == BM_END_OF_MAP))
 			break;
 
-		memory_bm_set_bit(bm, buf[j]);
+		if (memory_bm_pfn_present(bm, buf[j]))
+			memory_bm_set_bit(bm, buf[j]);
+		else
+			return -EFAULT;
 	}
+
+	return 0;
 }
 
 /* List of "safe" pages that may be used to store data loaded from the suspend
@@ -1608,7 +1626,7 @@ get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
 	pbe = chain_alloc(ca, sizeof(struct highmem_pbe));
 	if (!pbe) {
 		swsusp_free();
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 	pbe->orig_page = page;
 	if (safe_highmem_pages > 0) {
@@ -1677,7 +1695,7 @@ prepare_highmem_image(struct memory_bitmap *bm, unsigned int *nr_highmem_p)
 static inline void *
 get_highmem_page_buffer(struct page *page, struct chain_allocator *ca)
 {
-	return NULL;
+	return ERR_PTR(-EINVAL);
 }
 
 static inline void copy_last_highmem_page(void) {}
@@ -1788,8 +1806,13 @@ prepare_image(struct memory_bitmap *new_bm, struct memory_bitmap *bm)
 static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
 {
 	struct pbe *pbe;
-	struct page *page = pfn_to_page(memory_bm_next_pfn(bm));
+	struct page *page;
+	unsigned long pfn = memory_bm_next_pfn(bm);
 
+	if (pfn == BM_END_OF_MAP)
+		return ERR_PTR(-EFAULT);
+
+	page = pfn_to_page(pfn);
 	if (PageHighMem(page))
 		return get_highmem_page_buffer(page, ca);
 
@@ -1805,7 +1828,7 @@ static void *get_buffer(struct memory_bitmap *bm, struct chain_allocator *ca)
 	pbe = chain_alloc(ca, sizeof(struct pbe));
 	if (!pbe) {
 		swsusp_free();
-		return NULL;
+		return ERR_PTR(-ENOMEM);
 	}
 	pbe->orig_address = page_address(page);
 	pbe->address = safe_pages_list;
@@ -1868,7 +1891,10 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 				return error;
 
 		} else if (handle->prev <= nr_meta_pages) {
-			unpack_orig_pfns(buffer, &copy_bm);
+			error = unpack_orig_pfns(buffer, &copy_bm);
+			if (error)
+				return error;
+
 			if (handle->prev == nr_meta_pages) {
 				error = prepare_image(&orig_bm, &copy_bm);
 				if (error)
@@ -1879,12 +1905,14 @@ int snapshot_write_next(struct snapshot_handle *handle, size_t count)
 				restore_pblist = NULL;
 				handle->buffer = get_buffer(&orig_bm, &ca);
 				handle->sync_read = 0;
-				if (!handle->buffer)
-					return -ENOMEM;
+				if (IS_ERR(handle->buffer))
+					return PTR_ERR(handle->buffer);
 			}
 		} else {
 			copy_last_highmem_page();
 			handle->buffer = get_buffer(&orig_bm, &ca);
+			if (IS_ERR(handle->buffer))
+				return PTR_ERR(handle->buffer);
 			if (handle->buffer != buffer)
 				handle->sync_read = 0;
 		}
diff --git a/kernel/power/swsusp.c b/kernel/power/swsusp.c
index 023ff2a..a92c914 100644
--- a/kernel/power/swsusp.c
+++ b/kernel/power/swsusp.c
@@ -262,3 +262,125 @@ int swsusp_shrink_memory(void)
 
 	return 0;
 }
+
+/*
+ * Platforms, like ACPI, may want us to save some memory used by them during
+ * hibernation and to restore the contents of this memory during the subsequent
+ * resume.  The code below implements a mechanism allowing us to do that.
+ */
+
+struct nvs_page {
+	unsigned long phys_start;
+	unsigned int size;
+	void *kaddr;
+	void *data;
+	struct list_head node;
+};
+
+static LIST_HEAD(nvs_list);
+
+/**
+ *	hibernate_nvs_register - register platform NVS memory region to save
+ *	@start - physical address of the region
+ *	@size - size of the region
+ *
+ *	The NVS region need not be page-aligned (both ends) and we arrange
+ *	things so that the data from page-aligned addresses in this region will
+ *	be copied into separate RAM pages.
+ */
+int hibernate_nvs_register(unsigned long start, unsigned long size)
+{
+	struct nvs_page *entry, *next;
+
+	while (size > 0) {
+		unsigned int nr_bytes;
+
+		entry = kzalloc(sizeof(struct nvs_page), GFP_KERNEL);
+		if (!entry)
+			goto Error;
+
+		list_add_tail(&entry->node, &nvs_list);
+		entry->phys_start = start;
+		nr_bytes = PAGE_SIZE - (start & ~PAGE_MASK);
+		entry->size = (size < nr_bytes) ? size : nr_bytes;
+
+		start += entry->size;
+		size -= entry->size;
+	}
+	return 0;
+
+ Error:
+	list_for_each_entry_safe(entry, next, &nvs_list, node) {
+		list_del(&entry->node);
+		kfree(entry);
+	}
+	return -ENOMEM;
+}
+
+/**
+ *	hibernate_nvs_free - free data pages allocated for saving NVS regions
+ */
+void hibernate_nvs_free(void)
+{
+	struct nvs_page *entry;
+
+	list_for_each_entry(entry, &nvs_list, node)
+		if (entry->data) {
+			free_page((unsigned long)entry->data);
+			entry->data = NULL;
+			if (entry->kaddr) {
+				iounmap(entry->kaddr);
+				entry->kaddr = NULL;
+			}
+		}
+}
+
+/**
+ *	hibernate_nvs_alloc - allocate memory necessary for saving NVS regions
+ */
+int hibernate_nvs_alloc(void)
+{
+	struct nvs_page *entry;
+
+	list_for_each_entry(entry, &nvs_list, node) {
+		entry->data = (void *)__get_free_page(GFP_KERNEL);
+		if (!entry->data) {
+			hibernate_nvs_free();
+			return -ENOMEM;
+		}
+	}
+	return 0;
+}
+
+/**
+ *	hibernate_nvs_save - save NVS memory regions
+ */
+void hibernate_nvs_save(void)
+{
+	struct nvs_page *entry;
+
+	printk(KERN_INFO "PM: Saving platform NVS memory\n");
+
+	list_for_each_entry(entry, &nvs_list, node)
+		if (entry->data) {
+			entry->kaddr = ioremap(entry->phys_start, entry->size);
+			memcpy(entry->data, entry->kaddr, entry->size);
+		}
+}
+
+/**
+ *	hibernate_nvs_restore - restore NVS memory regions
+ *
+ *	This function is going to be called with interrupts disabled, so it
+ *	cannot iounmap the virtual addresses used to access the NVS region.
+ */
+void hibernate_nvs_restore(void)
+{
+	struct nvs_page *entry;
+
+	printk(KERN_INFO "PM: Restoring platform NVS memory\n");
+
+	list_for_each_entry(entry, &nvs_list, node)
+		if (entry->data)
+			memcpy(entry->kaddr, entry->data, entry->size);
+}