arch/microblaze/include/asm/segment.h

   1 /*
   2  * Copyright (C) 2008-2009 Michal Simek <monstr@monstr.eu>
   3  * Copyright (C) 2008-2009 PetaLogix
   4  * Copyright (C) 2006 Atmark Techno, Inc.
   5  *
   6  * This file is subject to the terms and conditions of the GNU General Public
   7  * License. See the file "COPYING" in the main directory of this archive
   8  * for more details.
   9  */
  10
  11 #ifndef _ASM_MICROBLAZE_SEGMENT_H
  12 #define _ASM_MICROBLAZE_SEGMENT_H
  13
  14 # ifndef __ASSEMBLY__
  15
  16 typedef struct {
  17         unsigned long seg;
  18 } mm_segment_t;
  19
  20 /*
  21  * On Microblaze the fs value is actually the top of the corresponding
  22  * address space.
  23  *
  24  * The fs value determines whether argument validity checking should be
  25  * performed or not. If get_fs() == USER_DS, checking is performed, with
  26  * get_fs() == KERNEL_DS, checking is bypassed.
  27  *
  28  * For historical reasons, these macros are grossly misnamed.
  29  *
  30  * For non-MMU arch like Microblaze, KERNEL_DS and USER_DS is equal.
  31  */
  32 # define MAKE_MM_SEG(s)       ((mm_segment_t) { (s) })
  33
  34 #  ifndef CONFIG_MMU
  35 #  define KERNEL_DS     MAKE_MM_SEG(0)
  36 #  define USER_DS       KERNEL_DS
  37 #  else
  38 #  define KERNEL_DS     MAKE_MM_SEG(0xFFFFFFFF)
  39 #  define USER_DS       MAKE_MM_SEG(TASK_SIZE - 1)
  40 #  endif
  41
  42 # define get_ds()       (KERNEL_DS)
  43 # define get_fs()       (current_thread_info()->addr_limit)
  44 # define set_fs(val)    (current_thread_info()->addr_limit = (val))
  45
  46 # define segment_eq(a, b)       ((a).seg == (b).seg)
  47
  48 # endif /* __ASSEMBLY__ */
  49 #endif /* _ASM_MICROBLAZE_SEGMENT_H */