x86: clarify use of _PAGE_CHG_MASK
authorJeremy Fitzhardinge <jeremy@goop.org>
Tue, 20 May 2008 07:26:22 +0000 (08:26 +0100)
committerLinus Torvalds <torvalds@linux-foundation.org>
Tue, 20 May 2008 14:51:21 +0000 (07:51 -0700)
_PAGE_CHG_MASK is defined as the set of bits not updated by
pte_modify(); specifically, the pfn itself, and the Accessed and Dirty
bits (which are updated by hardware).

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Tested-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
include/asm-x86/pgtable.h

index 55c3a0e..b816134 100644 (file)
@@ -57,6 +57,7 @@
 #define _KERNPG_TABLE  (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED |    \
                         _PAGE_DIRTY)
 
+/* Set of bits not changed in pte_modify */
 #define _PAGE_CHG_MASK (PTE_MASK | _PAGE_PCD | _PAGE_PWT |             \
                         _PAGE_ACCESSED | _PAGE_DIRTY)