barrier.h 1.4 KB

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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 (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. #ifndef __ASSEMBLY__
  17. #define nop() asm volatile ("nop")
  18. /*
  19. * Force strict CPU ordering.
  20. * And yes, this is required on UP too when we're talking
  21. * to devices.
  22. *
  23. * This implementation only contains a compiler barrier.
  24. */
  25. #define mb() asm volatile ("": : :"memory")
  26. #define rmb() mb()
  27. #define wmb() asm volatile ("": : :"memory")
  28. #ifdef CONFIG_SMP
  29. #define smp_mb() mb()
  30. #define smp_rmb() rmb()
  31. #define smp_wmb() wmb()
  32. #else
  33. #define smp_mb() barrier()
  34. #define smp_rmb() barrier()
  35. #define smp_wmb() barrier()
  36. #endif
  37. #define set_mb(var, value) do { var = value; mb(); } while (0)
  38. #define set_wmb(var, value) do { var = value; wmb(); } while (0)
  39. #define read_barrier_depends() do {} while (0)
  40. #define smp_read_barrier_depends() do {} while (0)
  41. #endif /* !__ASSEMBLY__ */
  42. #endif /* __ASM_GENERIC_BARRIER_H */