powerpc/mm: Fix _PAGE_CHG_MASK to protect _PAGE_SPECIAL
Fix _PAGE_CHG_MASK so that pte_modify() does not affect the _PAGE_SPECIAL bit.
Signed-off-by: Philippe Gerum <rpm@xenomai.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/arch/powerpc/include/asm/pgtable-4k.h b/arch/powerpc/include/asm/pgtable-4k.h
index 6b18ba9..1dbca4e7 100644
--- a/arch/powerpc/include/asm/pgtable-4k.h
+++ b/arch/powerpc/include/asm/pgtable-4k.h
@@ -60,7 +60,7 @@
/* It should be preserving the high 48 bits and then specifically */
/* preserving _PAGE_SECONDARY | _PAGE_GROUP_IX */
#define _PAGE_CHG_MASK (PAGE_MASK | _PAGE_ACCESSED | _PAGE_DIRTY | \
- _PAGE_HPTEFLAGS)
+ _PAGE_HPTEFLAGS | _PAGE_SPECIAL)
/* Bits to mask out from a PMD to get to the PTE page */
#define PMD_MASKED_BITS 0