| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame^] | 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 */ |