kernel/arch/arm/include/asm/mcs_spinlock.h

   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)                              \
   9 do {                                                                    \
  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)                            \
  17 do {                                                                    \
  18         smp_store_release(lock, 1);                                     \
  19         dsb_sev();                                                      \
  20 } while (0)
  21
  22 #endif  /* CONFIG_SMP */
  23 #endif  /* __ASM_MCS_LOCK_H */