1/*
 2 * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
 3 * Copyright (C) 2009 Wind River Systems Inc
 4 *
 5 * This file is subject to the terms and conditions of the GNU General Public
 6 * License.  See the file "COPYING" in the main directory of this archive
 7 * for more details.
 8 */
 9
10#ifndef _ASM_NIOS2_PGTABLE_BITS_H
11#define _ASM_NIOS2_PGTABLE_BITS_H
12
13/*
14 * These are actual hardware defined protection bits in the tlbacc register
15 * which looks like this:
16 *
17 * 31 30 ... 26 25 24 23 22 21 20 19 18 ...  1  0
18 * ignored........  C  R  W  X  G PFN............
19 */
20#define _PAGE_GLOBAL	(1<<20)
21#define _PAGE_EXEC	(1<<21)
22#define _PAGE_WRITE	(1<<22)
23#define _PAGE_READ	(1<<23)
24#define _PAGE_CACHED	(1<<24)	/* C: data access cacheable */
25
26/*
27 * Software defined bits. They are ignored by the hardware and always read back
28 * as zero, but can be written as non-zero.
29 */
30#define _PAGE_PRESENT	(1<<25)	/* PTE contains a translation */
31#define _PAGE_ACCESSED	(1<<26)	/* page referenced */
32#define _PAGE_DIRTY	(1<<27)	/* dirty page */
33
34/* We borrow bit 31 to store the exclusive marker in swap PTEs. */
35#define _PAGE_SWP_EXCLUSIVE	(1<<31)
36
37#endif /* _ASM_NIOS2_PGTABLE_BITS_H */