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885df91c DH |
1 | /* Generic barrier definitions, based on MN10300 definitions. |
2 | * | |
3 | * It should be possible to use these on really simple architectures, | |
4 | * but it serves more as a starting point for new ports. | |
5 | * | |
6 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
7 | * Written by David Howells (dhowells@redhat.com) | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or | |
10 | * modify it under the terms of the GNU General Public Licence | |
11 | * as published by the Free Software Foundation; either version | |
12 | * 2 of the Licence, or (at your option) any later version. | |
13 | */ | |
14 | #ifndef __ASM_GENERIC_BARRIER_H | |
15 | #define __ASM_GENERIC_BARRIER_H | |
16 | ||
17 | #ifndef __ASSEMBLY__ | |
18 | ||
19 | #define nop() asm volatile ("nop") | |
20 | ||
21 | /* | |
22 | * Force strict CPU ordering. | |
23 | * And yes, this is required on UP too when we're talking | |
24 | * to devices. | |
25 | * | |
26 | * This implementation only contains a compiler barrier. | |
27 | */ | |
28 | ||
29 | #define mb() asm volatile ("": : :"memory") | |
30 | #define rmb() mb() | |
31 | #define wmb() asm volatile ("": : :"memory") | |
32 | ||
33 | #ifdef CONFIG_SMP | |
34 | #define smp_mb() mb() | |
35 | #define smp_rmb() rmb() | |
36 | #define smp_wmb() wmb() | |
37 | #else | |
38 | #define smp_mb() barrier() | |
39 | #define smp_rmb() barrier() | |
40 | #define smp_wmb() barrier() | |
41 | #endif | |
42 | ||
43 | #define set_mb(var, value) do { var = value; mb(); } while (0) | |
44 | #define set_wmb(var, value) do { var = value; wmb(); } while (0) | |
45 | ||
46 | #define read_barrier_depends() do {} while (0) | |
47 | #define smp_read_barrier_depends() do {} while (0) | |
48 | ||
6fa3eb70 S |
49 | #define smp_store_release(p, v) \ |
50 | do { \ | |
51 | compiletime_assert_atomic_type(*p); \ | |
52 | smp_mb(); \ | |
53 | ACCESS_ONCE(*p) = (v); \ | |
54 | } while (0) | |
55 | ||
56 | #define smp_load_acquire(p) \ | |
57 | ({ \ | |
58 | typeof(*p) ___p1 = ACCESS_ONCE(*p); \ | |
59 | compiletime_assert_atomic_type(*p); \ | |
60 | smp_mb(); \ | |
61 | ___p1; \ | |
62 | }) | |
63 | ||
885df91c DH |
64 | #endif /* !__ASSEMBLY__ */ |
65 | #endif /* __ASM_GENERIC_BARRIER_H */ |