barrier.h 726 B

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #include <stdlib.h>
  3. #if defined(__i386__) || defined(__x86_64__)
  4. #define barrier() asm volatile("" ::: "memory")
  5. #define virt_mb() __sync_synchronize()
  6. #define virt_rmb() barrier()
  7. #define virt_wmb() barrier()
  8. /* Atomic store should be enough, but gcc generates worse code in that case. */
  9. #define virt_store_mb(var, value) do { \
  10. typeof(var) virt_store_mb_value = (value); \
  11. __atomic_exchange(&(var), &virt_store_mb_value, &virt_store_mb_value, \
  12. __ATOMIC_SEQ_CST); \
  13. barrier(); \
  14. } while (0);
  15. /* Weak barriers should be used. If not - it's a bug */
  16. # define mb() abort()
  17. # define dma_rmb() abort()
  18. # define dma_wmb() abort()
  19. #else
  20. #error Please fill in barrier macros
  21. #endif