xref: /OK3568_Linux_fs/kernel/arch/nios2/include/asm/pgtable-bits.h (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593Smuzhiyun /*
2*4882a593Smuzhiyun  * Copyright (C) 2011 Tobias Klauser <tklauser@distanz.ch>
3*4882a593Smuzhiyun  * Copyright (C) 2009 Wind River Systems Inc
4*4882a593Smuzhiyun  *
5*4882a593Smuzhiyun  * This file is subject to the terms and conditions of the GNU General Public
6*4882a593Smuzhiyun  * License.  See the file "COPYING" in the main directory of this archive
7*4882a593Smuzhiyun  * for more details.
8*4882a593Smuzhiyun  */
9*4882a593Smuzhiyun 
10*4882a593Smuzhiyun #ifndef _ASM_NIOS2_PGTABLE_BITS_H
11*4882a593Smuzhiyun #define _ASM_NIOS2_PGTABLE_BITS_H
12*4882a593Smuzhiyun 
13*4882a593Smuzhiyun /*
14*4882a593Smuzhiyun  * These are actual hardware defined protection bits in the tlbacc register
15*4882a593Smuzhiyun  * which looks like this:
16*4882a593Smuzhiyun  *
17*4882a593Smuzhiyun  * 31 30 ... 26 25 24 23 22 21 20 19 18 ...  1  0
18*4882a593Smuzhiyun  * ignored........  C  R  W  X  G PFN............
19*4882a593Smuzhiyun  */
20*4882a593Smuzhiyun #define _PAGE_GLOBAL	(1<<20)
21*4882a593Smuzhiyun #define _PAGE_EXEC	(1<<21)
22*4882a593Smuzhiyun #define _PAGE_WRITE	(1<<22)
23*4882a593Smuzhiyun #define _PAGE_READ	(1<<23)
24*4882a593Smuzhiyun #define _PAGE_CACHED	(1<<24)	/* C: data access cacheable */
25*4882a593Smuzhiyun 
26*4882a593Smuzhiyun /*
27*4882a593Smuzhiyun  * Software defined bits. They are ignored by the hardware and always read back
28*4882a593Smuzhiyun  * as zero, but can be written as non-zero.
29*4882a593Smuzhiyun  */
30*4882a593Smuzhiyun #define _PAGE_PRESENT	(1<<25)	/* PTE contains a translation */
31*4882a593Smuzhiyun #define _PAGE_ACCESSED	(1<<26)	/* page referenced */
32*4882a593Smuzhiyun #define _PAGE_DIRTY	(1<<27)	/* dirty page */
33*4882a593Smuzhiyun 
34*4882a593Smuzhiyun #endif /* _ASM_NIOS2_PGTABLE_BITS_H */
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