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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* segment.h: MMU segment settings
2 *
3 * Copyright (C) 2003 Red Hat, Inc. All Rights Reserved.
4 * Written by David Howells (dhowells@redhat.com)
5 *
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
10 */
11
12#ifndef _ASM_SEGMENT_H
13#define _ASM_SEGMENT_H
14
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16#ifndef __ASSEMBLY__
17
18typedef struct {
19 unsigned long seg;
20} mm_segment_t;
21
22#define MAKE_MM_SEG(s) ((mm_segment_t) { (s) })
23
24#define KERNEL_DS MAKE_MM_SEG(0xdfffffffUL)
25
26#ifdef CONFIG_MMU
27#define USER_DS MAKE_MM_SEG(TASK_SIZE - 1)
28#else
29#define USER_DS KERNEL_DS
30#endif
31
32#define get_ds() (KERNEL_DS)
33#define get_fs() (__current_thread_info->addr_limit)
34#define segment_eq(a,b) ((a).seg == (b).seg)
35#define __kernel_ds_p() segment_eq(get_fs(), KERNEL_DS)
36#define get_addr_limit() (get_fs().seg)
37
38#define set_fs(_x) \
39do { \
40 __current_thread_info->addr_limit = (_x); \
41} while(0)
42
43
44#endif /* __ASSEMBLY__ */
45#endif /* _ASM_SEGMENT_H */