Hibernation: Pass CR3 in the image header on x86_64

Since we already pass the address of restore_registers() in the image header,
we can also pass the value of the CR3 register from before the hibernation in
the same way.  This will allow us to avoid using init_level4_pgt page tables
during the restore.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 12 insertions, 4 deletions

diff --git a/arch/x86/kernel/suspend_64.c b/arch/x86/kernel/suspend_64.c
index 01fbfb018ca9..da10eef4c3ef 100644
--- a/arch/x86/kernel/suspend_64.c
+++ b/arch/x86/kernel/suspend_64.c
@@ -156,6 +156,12 @@ extern int restore_image(void);
  */
 unsigned long restore_jump_address;
 
+/*
+ * Value of the cr3 register from before the hibernation (this value is passed
+ * in the image header).
+ */
+unsigned long restore_cr3;
+
 pgd_t *temp_level4_pgt;
 
 void *relocated_restore_code;
@@ -254,7 +260,8 @@ int pfn_is_nosave(unsigned long pfn)
 
 struct restore_data_record {
         unsigned long jump_address;
-        unsigned long control;
+        unsigned long cr3;
+        unsigned long magic;
 };
 
 #define RESTORE_MAGIC   0x0123456789ABCDEFUL
@@ -271,7 +278,8 @@ int arch_hibernation_header_save(void *addr, unsigned int max_size)
         if (max_size < sizeof(struct restore_data_record))
                 return -EOVERFLOW;
         rdr->jump_address = restore_jump_address;
-        rdr->control = (restore_jump_address ^ RESTORE_MAGIC);
+        rdr->cr3 = restore_cr3;
+        rdr->magic = RESTORE_MAGIC;
         return 0;
 }
 
@@ -285,7 +293,7 @@ int arch_hibernation_header_restore(void *addr)
         struct restore_data_record *rdr = addr;
 
         restore_jump_address = rdr->jump_address;
-        return (rdr->control == (restore_jump_address ^ RESTORE_MAGIC)) ?
-                        0 : -EINVAL;
+        restore_cr3 = rdr->cr3;
+        return (rdr->magic == RESTORE_MAGIC) ? 0 : -EINVAL;
 }
 #endif /* CONFIG_HIBERNATION */