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1da177e4 LT |
1 | /* 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 | ||
15 | #include <linux/config.h> | |
16 | ||
17 | #ifndef __ASSEMBLY__ | |
18 | ||
19 | typedef struct { | |
20 | unsigned long seg; | |
21 | } mm_segment_t; | |
22 | ||
23 | #define MAKE_MM_SEG(s) ((mm_segment_t) { (s) }) | |
24 | ||
25 | #define KERNEL_DS MAKE_MM_SEG(0xdfffffffUL) | |
26 | ||
27 | #ifdef CONFIG_MMU | |
28 | #define USER_DS MAKE_MM_SEG(TASK_SIZE - 1) | |
29 | #else | |
30 | #define USER_DS KERNEL_DS | |
31 | #endif | |
32 | ||
33 | #define get_ds() (KERNEL_DS) | |
34 | #define get_fs() (__current_thread_info->addr_limit) | |
35 | #define segment_eq(a,b) ((a).seg == (b).seg) | |
36 | #define __kernel_ds_p() segment_eq(get_fs(), KERNEL_DS) | |
37 | #define get_addr_limit() (get_fs().seg) | |
38 | ||
39 | #define set_fs(_x) \ | |
40 | do { \ | |
41 | __current_thread_info->addr_limit = (_x); \ | |
42 | } while(0) | |
43 | ||
44 | ||
45 | #endif /* __ASSEMBLY__ */ | |
46 | #endif /* _ASM_SEGMENT_H */ |