revert "Hibernation: Use temporary page tables for kernel text mapping on x86_64"

Revert commit efa4d2fb047b25a6be67fe92178a2a78da6b3f6a ("Hibernation:
Use temporary page tables for kernel text mapping on x86_64") because it
causes my t61p to reboot right at the end of resume-from-disk.  For
reasons unknown at this time.

Cc: Pavel Machek <pavel@ucw.cz>
Cc: Andi Kleen <ak@suse.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 6 insertions, 33 deletions

diff --git a/arch/x86/kernel/suspend_64.c b/arch/x86/kernel/suspend_64.c
index db284ef44d53..2e5efaaf8800 100644
--- a/arch/x86/kernel/suspend_64.c
+++ b/arch/x86/kernel/suspend_64.c
@@ -192,42 +192,25 @@ static int res_phys_pud_init(pud_t *pud, unsigned long address, unsigned long en
         return 0;
 }
 
-static int res_kernel_text_pud_init(pud_t *pud, unsigned long start)
-{
-        pmd_t *pmd;
-        unsigned long paddr;
-
-        pmd = (pmd_t *)get_safe_page(GFP_ATOMIC);
-        if (!pmd)
-                return -ENOMEM;
-        set_pud(pud + pud_index(start), __pud(__pa(pmd) | _KERNPG_TABLE));
-        for (paddr = 0; paddr < KERNEL_TEXT_SIZE; pmd++, paddr += PMD_SIZE) {
-                unsigned long pe;
-
-                pe = __PAGE_KERNEL_LARGE_EXEC | _PAGE_GLOBAL | paddr;
-                pe &= __supported_pte_mask;
-                set_pmd(pmd, __pmd(pe));
-        }
-
-        return 0;
-}
-
 static int set_up_temporary_mappings(void)
 {
         unsigned long start, end, next;
-        pud_t *pud;
         int error;
 
         temp_level4_pgt = (pgd_t *)get_safe_page(GFP_ATOMIC);
         if (!temp_level4_pgt)
                 return -ENOMEM;
 
+        /* It is safe to reuse the original kernel mapping */
+        set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
+                init_level4_pgt[pgd_index(__START_KERNEL_map)]);
+
         /* Set up the direct mapping from scratch */
         start = (unsigned long)pfn_to_kaddr(0);
         end = (unsigned long)pfn_to_kaddr(end_pfn);
 
         for (; start < end; start = next) {
-                pud = (pud_t *)get_safe_page(GFP_ATOMIC);
+                pud_t *pud = (pud_t *)get_safe_page(GFP_ATOMIC);
                 if (!pud)
                         return -ENOMEM;
                 next = start + PGDIR_SIZE;
@@ -238,17 +221,7 @@ static int set_up_temporary_mappings(void)
                 set_pgd(temp_level4_pgt + pgd_index(start),
                         mk_kernel_pgd(__pa(pud)));
         }
-
-        /* Set up the kernel text mapping from scratch */
-        pud = (pud_t *)get_safe_page(GFP_ATOMIC);
-        if (!pud)
-                return -ENOMEM;
-        error = res_kernel_text_pud_init(pud, __START_KERNEL_map);
-        if (!error)
-                set_pgd(temp_level4_pgt + pgd_index(__START_KERNEL_map),
-                        __pgd(__pa(pud) | _PAGE_TABLE));
-
-        return error;
+        return 0;
 }
 
 int swsusp_arch_resume(void)