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git.proxmox.com Git - mirror_ubuntu-bionic-kernel.git/blob - arch/s390/include/asm/spinlock.h
3 * Copyright IBM Corp. 1999
4 * Author(s): Martin Schwidefsky (schwidefsky@de.ibm.com)
6 * Derived from "include/asm-i386/spinlock.h"
9 #ifndef __ASM_SPINLOCK_H
10 #define __ASM_SPINLOCK_H
12 #include <linux/smp.h>
13 #include <asm/atomic_ops.h>
14 #include <asm/barrier.h>
15 #include <asm/processor.h>
17 #define SPINLOCK_LOCKVAL (S390_lowcore.spinlock_lockval)
19 extern int spin_retry
;
22 static inline bool arch_vcpu_is_preempted(int cpu
) { return false; }
24 bool arch_vcpu_is_preempted(int cpu
);
27 #define vcpu_is_preempted arch_vcpu_is_preempted
30 * Simple spin lock operations. There are two variants, one clears IRQ's
31 * on the local processor, one does not.
33 * We make no fairness assumptions. They have a cost.
35 * (the type definitions are in asm/spinlock_types.h)
38 void arch_lock_relax(int cpu
);
40 void arch_spin_lock_wait(arch_spinlock_t
*);
41 int arch_spin_trylock_retry(arch_spinlock_t
*);
42 void arch_spin_lock_wait_flags(arch_spinlock_t
*, unsigned long flags
);
44 static inline void arch_spin_relax(arch_spinlock_t
*lock
)
46 arch_lock_relax(lock
->lock
);
49 static inline u32
arch_spin_lockval(int cpu
)
54 static inline int arch_spin_value_unlocked(arch_spinlock_t lock
)
56 return lock
.lock
== 0;
59 static inline int arch_spin_is_locked(arch_spinlock_t
*lp
)
61 return READ_ONCE(lp
->lock
) != 0;
64 static inline int arch_spin_trylock_once(arch_spinlock_t
*lp
)
67 return likely(arch_spin_value_unlocked(*lp
) &&
68 __atomic_cmpxchg_bool(&lp
->lock
, 0, SPINLOCK_LOCKVAL
));
71 static inline void arch_spin_lock(arch_spinlock_t
*lp
)
73 if (!arch_spin_trylock_once(lp
))
74 arch_spin_lock_wait(lp
);
77 static inline void arch_spin_lock_flags(arch_spinlock_t
*lp
,
80 if (!arch_spin_trylock_once(lp
))
81 arch_spin_lock_wait_flags(lp
, flags
);
84 static inline int arch_spin_trylock(arch_spinlock_t
*lp
)
86 if (!arch_spin_trylock_once(lp
))
87 return arch_spin_trylock_retry(lp
);
91 static inline void arch_spin_unlock(arch_spinlock_t
*lp
)
93 typecheck(int, lp
->lock
);
102 * Read-write spinlocks, allowing multiple readers
103 * but only one writer.
105 * NOTE! it is quite common to have readers in interrupts
106 * but no interrupt writers. For those circumstances we
107 * can "mix" irq-safe locks - any writer needs to get a
108 * irq-safe write-lock, but readers can get non-irqsafe
113 * read_can_lock - would read_trylock() succeed?
114 * @lock: the rwlock in question.
116 #define arch_read_can_lock(x) ((int)(x)->lock >= 0)
119 * write_can_lock - would write_trylock() succeed?
120 * @lock: the rwlock in question.
122 #define arch_write_can_lock(x) ((x)->lock == 0)
124 extern int _raw_read_trylock_retry(arch_rwlock_t
*lp
);
125 extern int _raw_write_trylock_retry(arch_rwlock_t
*lp
);
127 #define arch_read_lock_flags(lock, flags) arch_read_lock(lock)
128 #define arch_write_lock_flags(lock, flags) arch_write_lock(lock)
130 static inline int arch_read_trylock_once(arch_rwlock_t
*rw
)
132 int old
= ACCESS_ONCE(rw
->lock
);
133 return likely(old
>= 0 &&
134 __atomic_cmpxchg_bool(&rw
->lock
, old
, old
+ 1));
137 static inline int arch_write_trylock_once(arch_rwlock_t
*rw
)
139 int old
= ACCESS_ONCE(rw
->lock
);
140 return likely(old
== 0 &&
141 __atomic_cmpxchg_bool(&rw
->lock
, 0, 0x80000000));
144 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
146 #define __RAW_OP_OR "lao"
147 #define __RAW_OP_AND "lan"
148 #define __RAW_OP_ADD "laa"
150 #define __RAW_LOCK(ptr, op_val, op_string) \
154 typecheck(int *, ptr); \
156 op_string " %0,%2,%1\n" \
158 : "=d" (old_val), "+Q" (*ptr) \
164 #define __RAW_UNLOCK(ptr, op_val, op_string) \
168 typecheck(int *, ptr); \
170 op_string " %0,%2,%1\n" \
171 : "=d" (old_val), "+Q" (*ptr) \
177 extern void _raw_read_lock_wait(arch_rwlock_t
*lp
);
178 extern void _raw_write_lock_wait(arch_rwlock_t
*lp
, int prev
);
180 static inline void arch_read_lock(arch_rwlock_t
*rw
)
184 old
= __RAW_LOCK(&rw
->lock
, 1, __RAW_OP_ADD
);
186 _raw_read_lock_wait(rw
);
189 static inline void arch_read_unlock(arch_rwlock_t
*rw
)
191 __RAW_UNLOCK(&rw
->lock
, -1, __RAW_OP_ADD
);
194 static inline void arch_write_lock(arch_rwlock_t
*rw
)
198 old
= __RAW_LOCK(&rw
->lock
, 0x80000000, __RAW_OP_OR
);
200 _raw_write_lock_wait(rw
, old
);
201 rw
->owner
= SPINLOCK_LOCKVAL
;
204 static inline void arch_write_unlock(arch_rwlock_t
*rw
)
207 __RAW_UNLOCK(&rw
->lock
, 0x7fffffff, __RAW_OP_AND
);
210 #else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
212 extern void _raw_read_lock_wait(arch_rwlock_t
*lp
);
213 extern void _raw_write_lock_wait(arch_rwlock_t
*lp
);
215 static inline void arch_read_lock(arch_rwlock_t
*rw
)
217 if (!arch_read_trylock_once(rw
))
218 _raw_read_lock_wait(rw
);
221 static inline void arch_read_unlock(arch_rwlock_t
*rw
)
226 old
= ACCESS_ONCE(rw
->lock
);
227 } while (!__atomic_cmpxchg_bool(&rw
->lock
, old
, old
- 1));
230 static inline void arch_write_lock(arch_rwlock_t
*rw
)
232 if (!arch_write_trylock_once(rw
))
233 _raw_write_lock_wait(rw
);
234 rw
->owner
= SPINLOCK_LOCKVAL
;
237 static inline void arch_write_unlock(arch_rwlock_t
*rw
)
239 typecheck(int, rw
->lock
);
249 #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
251 static inline int arch_read_trylock(arch_rwlock_t
*rw
)
253 if (!arch_read_trylock_once(rw
))
254 return _raw_read_trylock_retry(rw
);
258 static inline int arch_write_trylock(arch_rwlock_t
*rw
)
260 if (!arch_write_trylock_once(rw
) && !_raw_write_trylock_retry(rw
))
262 rw
->owner
= SPINLOCK_LOCKVAL
;
266 static inline void arch_read_relax(arch_rwlock_t
*rw
)
268 arch_lock_relax(rw
->owner
);
271 static inline void arch_write_relax(arch_rwlock_t
*rw
)
273 arch_lock_relax(rw
->owner
);
276 #endif /* __ASM_SPINLOCK_H */