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(arch_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 /* 76 * Queued spinlocks rely heavily on smp_cond_load_relaxed() to busy-wait, 77 * which was found to have performance problems if implemented with 78 * the preferred spin_begin()/spin_end() SMT priority pattern. Use the 79 * generic version instead. 80 */ 81 82 #include <asm-generic/qspinlock.h> 83 84 #endif /* _ASM_POWERPC_QSPINLOCK_H */ 85