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authorMartin Schwidefsky <schwidefsky@de.ibm.com>2011-08-17 20:42:24 +0200
committerRafael J. Wysocki <rjw@sisk.pl>2011-10-16 23:27:46 +0200
commit85055dd805f0822f13f736bee2a521e222c38293 (patch)
treeedbad90395fc7471732edfb5372adcd7e55e791b /arch/s390
parentca123102f69fb260221502ade9bbc069290fae84 (diff)
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>
Diffstat (limited to 'arch/s390')
-rw-r--r--arch/s390/Kconfig1
-rw-r--r--arch/s390/kernel/suspend.c118
-rw-r--r--arch/s390/kernel/swsusp_asm64.S3
3 files changed, 122 insertions, 0 deletions
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index ed5cb5af528..6b99fc3f9b6 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 cf9e5c6d552..b6f9afed74e 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 51bcdb50a23..acb78cdee89 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