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 
16 #ifndef __ASSEMBLY__
17 
18 typedef struct {
19 	unsigned long seg;
20 } mm_segment_t;
21 
22 #define MAKE_MM_SEG(s)	((mm_segment_t) { (s) })
23 
24 #ifdef CONFIG_MMU
25 #define USER_DS			MAKE_MM_SEG(TASK_SIZE - 1)
26 #define KERNEL_DS		MAKE_MM_SEG(0xdfffffffUL)
27 #else
28 #define USER_DS			MAKE_MM_SEG(memory_end)
29 #define KERNEL_DS		MAKE_MM_SEG(0xe0000000UL)
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)					\
39 do {							\
40 	__current_thread_info->addr_limit = (_x);	\
41 } while(0)
42 
43 
44 #endif /* __ASSEMBLY__ */
45 #endif /* _ASM_SEGMENT_H */
46