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| 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 ([email protected]) |
| 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 | + |
| 49 | +#endif /* !__ASSEMBLY__ */ |
| 50 | +#endif /* __ASM_GENERIC_BARRIER_H */ |
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