1 #ifndef _ASM_POWERPC_MEMBARRIER_H 2 #define _ASM_POWERPC_MEMBARRIER_H 3 4 static inline void membarrier_arch_switch_mm(struct mm_struct *prev, 5 struct mm_struct *next, 6 struct task_struct *tsk) 7 { 8 /* 9 * Only need the full barrier when switching between processes. 10 * Barrier when switching from kernel to userspace is not 11 * required here, given that it is implied by mmdrop(). Barrier 12 * when switching from userspace to kernel is not needed after 13 * store to rq->curr. 14 */ 15 if (IS_ENABLED(CONFIG_SMP) && 16 likely(!(atomic_read(&next->membarrier_state) & 17 (MEMBARRIER_STATE_PRIVATE_EXPEDITED | 18 MEMBARRIER_STATE_GLOBAL_EXPEDITED)) || !prev)) 19 return; 20 21 /* 22 * The membarrier system call requires a full memory barrier 23 * after storing to rq->curr, before going back to user-space. 24 */ 25 smp_mb(); 26 } 27 28 #endif /* _ASM_POWERPC_MEMBARRIER_H */ 29