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 */