6 files changed, 177 insertions, 0 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index ed5cb5af5281..6b99fc3f9b63 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -91,6 +91,7 @@ config S390
         select HAVE_ARCH_MUTEX_CPU_RELAX
         select HAVE_ARCH_JUMP_LABEL if !MARCH_G5
         select HAVE_RCU_TABLE_FREE if SMP
+        select ARCH_SAVE_PAGE_KEYS if HIBERNATION
         select ARCH_INLINE_SPIN_TRYLOCK
         select ARCH_INLINE_SPIN_TRYLOCK_BH
         select ARCH_INLINE_SPIN_LOCK
diff --git a/arch/s390/kernel/suspend.c b/arch/s390/kernel/suspend.c
index cf9e5c6d5527..b6f9afed74ec 100644
--- a/arch/s390/kernel/suspend.c
+++ b/arch/s390/kernel/suspend.c
@@ -7,6 +7,7 @@
  */
 
 #include <linux/pfn.h>
+#include <linux/mm.h>
 #include <asm/system.h>
 
 /*
@@ -14,6 +15,123 @@
  */
 extern const void __nosave_begin, __nosave_end;
 
+/*
+ * The restore of the saved pages in an hibernation image will set
+ * the change and referenced bits in the storage key for each page.
+ * Overindication of the referenced bits after an hibernation cycle
+ * does not cause any harm but the overindication of the change bits
+ * would cause trouble.
+ * Use the ARCH_SAVE_PAGE_KEYS hooks to save the storage key of each
+ * page to the most significant byte of the associated page frame
+ * number in the hibernation image.
+ */
+
+/*
+ * Key storage is allocated as a linked list of pages.
+ * The size of the keys array is (PAGE_SIZE - sizeof(long))
+ */
+struct page_key_data {
+        struct page_key_data *next;
+        unsigned char data[];
+};
+
+#define PAGE_KEY_DATA_SIZE      (PAGE_SIZE - sizeof(struct page_key_data *))
+
+static struct page_key_data *page_key_data;
+static struct page_key_data *page_key_rp, *page_key_wp;
+static unsigned long page_key_rx, page_key_wx;
+
+/*
+ * For each page in the hibernation image one additional byte is
+ * stored in the most significant byte of the page frame number.
+ * On suspend no additional memory is required but on resume the
+ * keys need to be memorized until the page data has been restored.
+ * Only then can the storage keys be set to their old state.
+ */
+unsigned long page_key_additional_pages(unsigned long pages)
+{
+        return DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
+}
+
+/*
+ * Free page_key_data list of arrays.
+ */
+void page_key_free(void)
+{
+        struct page_key_data *pkd;
+
+        while (page_key_data) {
+                pkd = page_key_data;
+                page_key_data = pkd->next;
+                free_page((unsigned long) pkd);
+        }
+}
+
+/*
+ * Allocate page_key_data list of arrays with enough room to store
+ * one byte for each page in the hibernation image.
+ */
+int page_key_alloc(unsigned long pages)
+{
+        struct page_key_data *pk;
+        unsigned long size;
+
+        size = DIV_ROUND_UP(pages, PAGE_KEY_DATA_SIZE);
+        while (size--) {
+                pk = (struct page_key_data *) get_zeroed_page(GFP_KERNEL);
+                if (!pk) {
+                        page_key_free();
+                        return -ENOMEM;
+                }
+                pk->next = page_key_data;
+                page_key_data = pk;
+        }
+        page_key_rp = page_key_wp = page_key_data;
+        page_key_rx = page_key_wx = 0;
+        return 0;
+}
+
+/*
+ * Save the storage key into the upper 8 bits of the page frame number.
+ */
+void page_key_read(unsigned long *pfn)
+{
+        unsigned long addr;
+
+        addr = (unsigned long) page_address(pfn_to_page(*pfn));
+        *(unsigned char *) pfn = (unsigned char) page_get_storage_key(addr);
+}
+
+/*
+ * Extract the storage key from the upper 8 bits of the page frame number
+ * and store it in the page_key_data list of arrays.
+ */
+void page_key_memorize(unsigned long *pfn)
+{
+        page_key_wp->data[page_key_wx] = *(unsigned char *) pfn;
+        *(unsigned char *) pfn = 0;
+        if (++page_key_wx < PAGE_KEY_DATA_SIZE)
+                return;
+        page_key_wp = page_key_wp->next;
+        page_key_wx = 0;
+}
+
+/*
+ * Get the next key from the page_key_data list of arrays and set the
+ * storage key of the page referred by @address. If @address refers to
+ * a "safe" page the swsusp_arch_resume code will transfer the storage
+ * key from the buffer page to the original page.
+ */
+void page_key_write(void *address)
+{
+        page_set_storage_key((unsigned long) address,
+                             page_key_rp->data[page_key_rx], 0);
+        if (++page_key_rx >= PAGE_KEY_DATA_SIZE)
+                return;
+        page_key_rp = page_key_rp->next;
+        page_key_rx = 0;
+}
+
 int pfn_is_nosave(unsigned long pfn)
 {
         unsigned long nosave_begin_pfn = PFN_DOWN(__pa(&__nosave_begin));
diff --git a/arch/s390/kernel/swsusp_asm64.S b/arch/s390/kernel/swsusp_asm64.S
index 51bcdb50a230..acb78cdee896 100644
--- a/arch/s390/kernel/swsusp_asm64.S
+++ b/arch/s390/kernel/swsusp_asm64.S
@@ -136,11 +136,14 @@ ENTRY(swsusp_arch_resume)
 0:
         lg      %r2,8(%r1)
         lg      %r4,0(%r1)
+        iske    %r0,%r4
         lghi    %r3,PAGE_SIZE
         lghi    %r5,PAGE_SIZE
 1:
         mvcle   %r2,%r4,0
         jo      1b
+        lg      %r2,8(%r1)
+        sske    %r0,%r2
         lg      %r1,16(%r1)
         ltgr    %r1,%r1
         jnz     0b
diff --git a/include/linux/suspend.h b/include/linux/suspend.h
index 76f42e49b72d..46f3548aef2d 100644
--- a/include/linux/suspend.h
+++ b/include/linux/suspend.h
@@ -386,4 +386,38 @@ static inline void unlock_system_sleep(void)
 }
 #endif
 
+#ifdef CONFIG_ARCH_SAVE_PAGE_KEYS
+/*
+ * The ARCH_SAVE_PAGE_KEYS functions can be used by an architecture
+ * to save/restore additional information to/from the array of page
+ * frame numbers in the hibernation image. For s390 this is used to
+ * save and restore the storage key for each page that is included
+ * in the hibernation image.
+ */
+unsigned long page_key_additional_pages(unsigned long pages);
+int page_key_alloc(unsigned long pages);
+void page_key_free(void);
+void page_key_read(unsigned long *pfn);
+void page_key_memorize(unsigned long *pfn);
+void page_key_write(void *address);
+
+#else /* !CONFIG_ARCH_SAVE_PAGE_KEYS */
+
+static inline unsigned long page_key_additional_pages(unsigned long pages)
+{
+        return 0;
+}
+
+static inline int  page_key_alloc(unsigned long pages)
+{
+        return 0;
+}
+
+static inline void page_key_free(void) {}
+static inline void page_key_read(unsigned long *pfn) {}
+static inline void page_key_memorize(unsigned long *pfn) {}
+static inline void page_key_write(void *address) {}
+
+#endif /* !CONFIG_ARCH_SAVE_PAGE_KEYS */
+
 #endif /* _LINUX_SUSPEND_H */
diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 3744c594b19b..e01e6899592c 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -65,6 +65,9 @@ config HIBERNATION
 
           For more information take a look at <file:Documentation/power/swsusp.txt>.
 
+config ARCH_SAVE_PAGE_KEYS
+        bool
+
 config PM_STD_PARTITION
         string "Default resume partition"
         depends on HIBERNATION
diff --git a/kernel/power/snapshot.c b/kernel/power/snapshot.c
index 06efa54f93d6..cbe2c1441392 100644
--- a/kernel/power/snapshot.c
+++ b/kernel/power/snapshot.c
@@ -1339,6 +1339,9 @@ int hibernate_preallocate_memory(void)
         count += highmem;
         count -= totalreserve_pages;
 
+        /* Add number of pages required for page keys (s390 only). */
+        size += page_key_additional_pages(saveable);
+
         /* Compute the maximum number of saveable pages to leave in memory. */
         max_size = (count - (size + PAGES_FOR_IO)) / 2
                         - 2 * DIV_ROUND_UP(reserved_size, PAGE_SIZE);
@@ -1662,6 +1665,8 @@ pack_pfns(unsigned long *buf, struct memory_bitmap *bm)
                 buf[j] = memory_bm_next_pfn(bm);
                 if (unlikely(buf[j] == BM_END_OF_MAP))
                         break;
+                /* Save page key for data page (s390 only). */
+                page_key_read(buf + j);
         }
 }
 
@@ -1821,6 +1826,9 @@ static int unpack_orig_pfns(unsigned long *buf, struct memory_bitmap *bm)
                 if (unlikely(buf[j] == BM_END_OF_MAP))
                         break;
 
+                /* Extract and buffer page key for data page (s390 only). */
+                page_key_memorize(buf + j);
+
                 if (memory_bm_pfn_present(bm, buf[j]))
                         memory_bm_set_bit(bm, buf[j]);
                 else
@@ -2223,6 +2231,11 @@ int snapshot_write_next(struct snapshot_handle *handle)
                 if (error)
                         return error;
 
+                /* Allocate buffer for page keys. */
+                error = page_key_alloc(nr_copy_pages);
+                if (error)
+                        return error;
+
         } else if (handle->cur <= nr_meta_pages + 1) {
                 error = unpack_orig_pfns(buffer, &copy_bm);
                 if (error)
@@ -2243,6 +2256,8 @@ int snapshot_write_next(struct snapshot_handle *handle)
                 }
         } else {
                 copy_last_highmem_page();
+                /* Restore page key for data page (s390 only). */
+                page_key_write(handle->buffer);
                 handle->buffer = get_buffer(&orig_bm, &ca);
                 if (IS_ERR(handle->buffer))
                         return PTR_ERR(handle->buffer);
@@ -2264,6 +2279,9 @@ int snapshot_write_next(struct snapshot_handle *handle)
 void snapshot_write_finalize(struct snapshot_handle *handle)
 {
         copy_last_highmem_page();
+        /* Restore page key for data page (s390 only). */
+        page_key_write(handle->buffer);
+        page_key_free();
         /* Free only if we have loaded the image entirely */
         if (handle->cur > 1 && handle->cur > nr_meta_pages + nr_copy_pages) {
                 memory_bm_free(&orig_bm, PG_UNSAFE_CLEAR);