Merge branch 'suspend' into release

3 files changed, 324 insertions, 174 deletions

diff --git a/kernel/power/disk.c b/kernel/power/disk.c
index c9d74083746f..096fe4899ea4 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 5d2ab836e998..f5fc2d7680f2 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 023ff2a31d89..a92c91451559 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);
+}