arch/arm/include/asm/mcs_spinlock.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_MCS_LOCK_H
   3 #define __ASM_MCS_LOCK_H
   4
   5 #ifdef CONFIG_SMP
   6 #include <asm/spinlock.h>
   7
   8 /* MCS spin-locking. */
   9 #define arch_mcs_spin_lock_contended(lock)                              \
  10 do {                                                                    \
  11         /* Ensure prior stores are observed before we enter wfe. */     \
  12         smp_mb();                                                       \
  13         while (!(smp_load_acquire(lock)))                               \
  14                 wfe();                                                  \
  15 } while (0)                                                             \
  16
  17 #define arch_mcs_spin_unlock_contended(lock)                            \
  18 do {                                                                    \
  19         smp_store_release(lock, 1);                                     \
  20         dsb_sev();                                                      \
  21 } while (0)
  22
  23 #endif  /* CONFIG_SMP */
  24 #endif  /* __ASM_MCS_LOCK_H */