[PATCH] lock PTE before updating it in 440/BookE page fault handler

Fix 44x and BookE page fault handler to correctly lock PTE before
trying to pte_update() it, otherwise this PTE might be swapped out
after pte_present() check but before pte_uptdate() call, resulting in
corrupted PTE. This can happen with enabled preemption and low memory
condition.

Signed-off-by: Eugene Surovegin <ebs@ebshome.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 2 insertions, 1 deletions

diff --git a/include/asm-ppc/pgtable.h b/include/asm-ppc/pgtable.h
index e1c62da12e74..570b355162fa 100644
--- a/include/asm-ppc/pgtable.h
+++ b/include/asm-ppc/pgtable.h
@@ -837,7 +837,8 @@ static inline int io_remap_pfn_range(struct vm_area_struct *vma,
  */
 #define pgtable_cache_init()    do { } while (0)
 
-extern int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep);
+extern int get_pteptr(struct mm_struct *mm, unsigned long addr, pte_t **ptep,
+                      pmd_t **pmdp);
 
 #include <asm-generic/pgtable.h>