projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| 93ea02bb PZ |
1 | /* |
| 2 | * Generic barrier definitions, originally based on MN10300 definitions. | |
| 885df91c DH |
3 | * |
| 4 | * It should be possible to use these on really simple architectures, | |
| 5 | * but it serves more as a starting point for new ports. | |
| 6 | * | |
| 7 | * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. | |
| 8 | * Written by David Howells (dhowells@redhat.com) | |
| 9 | * | |
| 10 | * This program is free software; you can redistribute it and/or | |
| 11 | * modify it under the terms of the GNU General Public Licence | |
| 12 | * as published by the Free Software Foundation; either version | |
| 13 | * 2 of the Licence, or (at your option) any later version. | |
| 14 | */ | |
| 15 | #ifndef __ASM_GENERIC_BARRIER_H | |
| 16 | #define __ASM_GENERIC_BARRIER_H | |
| 17 | ||
| 18 | #ifndef __ASSEMBLY__ | |
| 19 | ||
| 93ea02bb PZ |
20 | #include <linux/compiler.h> |
| 21 | ||
| 22 | #ifndef nop | |
| 23 | #define nop() asm volatile ("nop") | |
| 24 | #endif | |
| 885df91c DH |
25 | |
| 26 | /* | |
| 93ea02bb PZ |
27 | * Force strict CPU ordering. And yes, this is required on UP too when we're |
| 28 | * talking to devices. | |
| 885df91c | 29 | * |
| 93ea02bb | 30 | * Fall back to compiler barriers if nothing better is provided. |
| 885df91c DH |
31 | */ |
| 32 | ||
| 93ea02bb PZ |
33 | #ifndef mb |
| 34 | #define mb() barrier() | |
| 35 | #endif | |
| 36 | ||
| 37 | #ifndef rmb | |
| 885df91c | 38 | #define rmb() mb() |
| 93ea02bb PZ |
39 | #endif |
| 40 | ||
| 41 | #ifndef wmb | |
| 42 | #define wmb() mb() | |
| 43 | #endif | |
| 44 | ||
| 1077fa36 AD |
45 | #ifndef dma_rmb |
| 46 | #define dma_rmb() rmb() | |
| 47 | #endif | |
| 48 | ||
| 49 | #ifndef dma_wmb | |
| 50 | #define dma_wmb() wmb() | |
| 51 | #endif | |
| 52 | ||
| 93ea02bb PZ |
53 | #ifndef read_barrier_depends |
| 54 | #define read_barrier_depends() do { } while (0) | |
| 55 | #endif | |
| 885df91c DH |
56 | |
| 57 | #ifdef CONFIG_SMP | |
| 58 | #define smp_mb() mb() | |
| 59 | #define smp_rmb() rmb() | |
| 60 | #define smp_wmb() wmb() | |
| 93ea02bb | 61 | #define smp_read_barrier_depends() read_barrier_depends() |
| 885df91c DH |
62 | #else |
| 63 | #define smp_mb() barrier() | |
| 64 | #define smp_rmb() barrier() | |
| 65 | #define smp_wmb() barrier() | |
| 93ea02bb | 66 | #define smp_read_barrier_depends() do { } while (0) |
| 885df91c DH |
67 | #endif |
| 68 | ||
| 93ea02bb PZ |
69 | #ifndef set_mb |
| 70 | #define set_mb(var, value) do { (var) = (value); mb(); } while (0) | |
| 71 | #endif | |
| 885df91c | 72 | |
| febdbfe8 PZ |
73 | #ifndef smp_mb__before_atomic |
| 74 | #define smp_mb__before_atomic() smp_mb() | |
| 75 | #endif | |
| 76 | ||
| 77 | #ifndef smp_mb__after_atomic | |
| 78 | #define smp_mb__after_atomic() smp_mb() | |
| 79 | #endif | |
| 80 | ||
| 47933ad4 PZ |
81 | #define smp_store_release(p, v) \ |
| 82 | do { \ | |
| 83 | compiletime_assert_atomic_type(*p); \ | |
| 84 | smp_mb(); \ | |
| 85 | ACCESS_ONCE(*p) = (v); \ | |
| 86 | } while (0) | |
| 87 | ||
| 88 | #define smp_load_acquire(p) \ | |
| 89 | ({ \ | |
| 90 | typeof(*p) ___p1 = ACCESS_ONCE(*p); \ | |
| 91 | compiletime_assert_atomic_type(*p); \ | |
| 92 | smp_mb(); \ | |
| 93 | ___p1; \ | |
| 94 | }) | |
| 95 | ||
| 885df91c DH |
96 | #endif /* !__ASSEMBLY__ */ |
| 97 | #endif /* __ASM_GENERIC_BARRIER_H */ |