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 (likely(!(atomic_read(&next->membarrier_state) & 16 (MEMBARRIER_STATE_PRIVATE_EXPEDITED | 17 MEMBARRIER_STATE_GLOBAL_EXPEDITED)) || !prev)) 18 return; 19 20 /* 21 * The membarrier system call requires a full memory barrier 22 * after storing to rq->curr, before going back to user-space. 23 */ 24 smp_mb(); 25 } 26 27 #endif /* _ASM_POWERPC_MEMBARRIER_H */ 28