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 #define smp_mb__after_spinlock()   smp_mb()
48 
49 static __always_inline int queued_spin_is_locked(struct qspinlock *lock)
50 {
51 	/*
52 	 * This barrier was added to simple spinlocks by commit 51d7d5205d338,
53 	 * but it should now be possible to remove it, asm arm64 has done with
54 	 * commit c6f5d02b6a0f.
55 	 */
56 	smp_mb();
57 	return atomic_read(&lock->val);
58 }
59 #define queued_spin_is_locked queued_spin_is_locked
60 
61 #ifdef CONFIG_PARAVIRT_SPINLOCKS
62 #define SPIN_THRESHOLD (1<<15) /* not tuned */
63 
64 static __always_inline void pv_wait(u8 *ptr, u8 val)
65 {
66 	if (*ptr != val)
67 		return;
68 	yield_to_any();
69 	/*
70 	 * We could pass in a CPU here if waiting in the queue and yield to
71 	 * the previous CPU in the queue.
72 	 */
73 }
74 
75 static __always_inline void pv_kick(int cpu)
76 {
77 	prod_cpu(cpu);
78 }
79 
80 extern void __pv_init_lock_hash(void);
81 
82 static inline void pv_spinlocks_init(void)
83 {
84 	__pv_init_lock_hash();
85 }
86 
87 #endif
88 
89 #include <asm-generic/qspinlock.h>
90 
91 #endif /* _ASM_POWERPC_QSPINLOCK_H */
92