barrier.h 1.3 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 */
  2. #ifndef _TOOLS_LINUX_ASM_X86_BARRIER_H
  3. #define _TOOLS_LINUX_ASM_X86_BARRIER_H
  4. /*
  5. * Copied from the Linux kernel sources, and also moving code
  6. * out from tools/perf/perf-sys.h so as to make it be located
  7. * in a place similar as in the kernel sources.
  8. *
  9. * Force strict CPU ordering.
  10. * And yes, this is required on UP too when we're talking
  11. * to devices.
  12. */
  13. #if defined(__i386__)
  14. /*
  15. * Some non-Intel clones support out of order store. wmb() ceases to be a
  16. * nop for these.
  17. */
  18. #define mb() asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
  19. #define rmb() asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
  20. #define wmb() asm volatile("lock; addl $0,0(%%esp)" ::: "memory")
  21. #elif defined(__x86_64__)
  22. #define mb() asm volatile("mfence" ::: "memory")
  23. #define rmb() asm volatile("lfence" ::: "memory")
  24. #define wmb() asm volatile("sfence" ::: "memory")
  25. #define smp_rmb() barrier()
  26. #define smp_wmb() barrier()
  27. #define smp_mb() asm volatile("lock; addl $0,-132(%%rsp)" ::: "memory", "cc")
  28. #endif
  29. #if defined(__x86_64__)
  30. #define smp_store_release(p, v) \
  31. do { \
  32. barrier(); \
  33. WRITE_ONCE(*p, v); \
  34. } while (0)
  35. #define smp_load_acquire(p) \
  36. ({ \
  37. typeof(*p) ___p1 = READ_ONCE(*p); \
  38. barrier(); \
  39. ___p1; \
  40. })
  41. #endif /* defined(__x86_64__) */
  42. #endif /* _TOOLS_LINUX_ASM_X86_BARRIER_H */