powerpc/mm: Implement _PAGE_SPECIAL & pte_special() for 64-bit
Implement _PAGE_SPECIAL and pte_special() for 64-bit powerpc. This bit will
be used by the fast get_user_pages() to differenciate PTEs that correspond
to a valid struct page from special mappings that don't such as IO mappings
obtained via io_remap_pfn_ranges().
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/include/asm-powerpc/pgtable-64k.h b/include/asm-powerpc/pgtable-64k.h
index 7e54adb..07b0d8f 100644
--- a/include/asm-powerpc/pgtable-64k.h
+++ b/include/asm-powerpc/pgtable-64k.h
@@ -70,6 +70,8 @@
#define PGDIR_MASK (~(PGDIR_SIZE-1))
/* Additional PTE bits (don't change without checking asm in hash_low.S) */
+#define __HAVE_ARCH_PTE_SPECIAL
+#define _PAGE_SPECIAL 0x00000400 /* software: special page */
#define _PAGE_HPTE_SUB 0x0ffff000 /* combo only: sub pages HPTE bits */
#define _PAGE_HPTE_SUB0 0x08000000 /* combo only: first sub page */
#define _PAGE_COMBO 0x10000000 /* this is a combo 4k page */