arch/nios2/include/asm/pgtable-bits.h

   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 #endif /* _ASM_NIOS2_PGTABLE_BITS_H */