arch/powerpc/include/asm/qspinlock.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _ASM_POWERPC_QSPINLOCK_H
   3 #define _ASM_POWERPC_QSPINLOCK_H
   4
   5 #include <asm-generic/qspinlock_types.h>
   6 #include <asm/paravirt.h>
   7
   8 #define _Q_PENDING_LOOPS        (1 << 9) /* not tuned */
   9
  10 #ifdef CONFIG_PARAVIRT_SPINLOCKS
  11 extern void native_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
  12 extern void __pv_queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
  13 extern void __pv_queued_spin_unlock(struct qspinlock *lock);
  14
  15 static __always_inline void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val)
  16 {
  17         if (!is_shared_processor())
  18                 native_queued_spin_lock_slowpath(lock, val);
  19         else
  20                 __pv_queued_spin_lock_slowpath(lock, val);
  21 }
  22
  23 #define queued_spin_unlock queued_spin_unlock
  24 static inline void queued_spin_unlock(struct qspinlock *lock)
  25 {
  26         if (!is_shared_processor())
  27                 smp_store_release(&lock->locked, 0);
  28         else
  29                 __pv_queued_spin_unlock(lock);
  30 }
  31
  32 #else
  33 extern void queued_spin_lock_slowpath(struct qspinlock *lock, u32 val);
  34 #endif
  35
  36 static __always_inline void queued_spin_lock(struct qspinlock *lock)
  37 {
  38         u32 val = 0;
  39
  40         if (likely(atomic_try_cmpxchg_lock(&lock->val, &val, _Q_LOCKED_VAL)))
  41                 return;
  42
  43         queued_spin_lock_slowpath(lock, val);
  44 }
  45 #define queued_spin_lock queued_spin_lock
  46
  47 #ifdef CONFIG_PARAVIRT_SPINLOCKS
  48 #define SPIN_THRESHOLD (1<<15) /* not tuned */
  49
  50 static __always_inline void pv_wait(u8 *ptr, u8 val)
  51 {
  52         if (*ptr != val)
  53                 return;
  54         yield_to_any();
  55         /*
  56          * We could pass in a CPU here if waiting in the queue and yield to
  57          * the previous CPU in the queue.
  58          */
  59 }
  60
  61 static __always_inline void pv_kick(int cpu)
  62 {
  63         prod_cpu(cpu);
  64 }
  65
  66 extern void __pv_init_lock_hash(void);
  67
  68 static inline void pv_spinlocks_init(void)
  69 {
  70         __pv_init_lock_hash();
  71 }
  72
  73 #endif
  74
  75 #include <asm-generic/qspinlock.h>
  76
  77 #endif /* _ASM_POWERPC_QSPINLOCK_H */