LXR linux/arch/arm/include/asm/mcs

   1#ifndef __ASM_MCS_LOCK_H
   2#define __ASM_MCS_LOCK_H
   3
   4#ifdef CONFIG_SMP
   5#include <asm/spinlock.h>
   6
   7/* MCS spin-locking. */
   8#define arch_mcs_spin_lock_contended(lock)                              \
   9do {                                                                    \
  10        /* Ensure prior stores are observed before we enter wfe. */     \
  11        smp_mb();                                                       \
  12        while (!(smp_load_acquire(lock)))                               \
  13                wfe();                                                  \
  14} while (0)                                                             \
  15
  16#define arch_mcs_spin_unlock_contended(lock)                            \
  17do {                                                                    \
  18        smp_store_release(lock, 1);                                     \
  19        dsb_sev();                                                      \
  20} while (0)
  21
  22#endif  /* CONFIG_SMP */
  23#endif  /* __ASM_MCS_LOCK_H */
  24