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 */
38