PM / Hibernate: Include storage keys in hibernation image on s390

For s390 there is one additional byte associated with each page,
the storage key. This byte contains the referenced and changed
bits and needs to be included into the hibernation image.
If the storage keys are not restored to their previous state all
original pages would appear to be dirty. This can cause
inconsistencies e.g. with read-only filesystems.

Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>

1 files changed, 34 insertions, 0 deletions

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 */