LXR linux/arch/powerpc/include/asm/membarrier.h

   1#ifndef _ASM_POWERPC_MEMBARRIER_H
   2#define _ASM_POWERPC_MEMBARRIER_H
   3
   4static 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