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72 lines
2.2 KiB
72 lines
2.2 KiB
#ifndef __LINUX_SPINLOCK_UP_H |
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#define __LINUX_SPINLOCK_UP_H |
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#ifndef __LINUX_SPINLOCK_H |
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# error "please don't include this file directly" |
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#endif |
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#include <asm/processor.h> /* for cpu_relax() */ |
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#include <asm/barrier.h> |
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/* |
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* include/linux/spinlock_up.h - UP-debug version of spinlocks. |
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* |
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* portions Copyright 2005, Red Hat, Inc., Ingo Molnar |
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* Released under the General Public License (GPL). |
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* |
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* In the debug case, 1 means unlocked, 0 means locked. (the values |
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* are inverted, to catch initialization bugs) |
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* |
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* No atomicity anywhere, we are on UP. However, we still need |
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* the compiler barriers, because we do not want the compiler to |
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* move potentially faulting instructions (notably user accesses) |
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* into the locked sequence, resulting in non-atomic execution. |
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*/ |
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#ifdef CONFIG_DEBUG_SPINLOCK |
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#define arch_spin_is_locked(x) ((x)->slock == 0) |
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static inline void arch_spin_lock(arch_spinlock_t *lock) |
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{ |
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lock->slock = 0; |
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barrier(); |
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} |
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static inline int arch_spin_trylock(arch_spinlock_t *lock) |
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{ |
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char oldval = lock->slock; |
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lock->slock = 0; |
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barrier(); |
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return oldval > 0; |
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} |
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static inline void arch_spin_unlock(arch_spinlock_t *lock) |
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{ |
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barrier(); |
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lock->slock = 1; |
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} |
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/* |
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* Read-write spinlocks. No debug version. |
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*/ |
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#define arch_read_lock(lock) do { barrier(); (void)(lock); } while (0) |
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#define arch_write_lock(lock) do { barrier(); (void)(lock); } while (0) |
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#define arch_read_trylock(lock) ({ barrier(); (void)(lock); 1; }) |
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#define arch_write_trylock(lock) ({ barrier(); (void)(lock); 1; }) |
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#define arch_read_unlock(lock) do { barrier(); (void)(lock); } while (0) |
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#define arch_write_unlock(lock) do { barrier(); (void)(lock); } while (0) |
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#else /* DEBUG_SPINLOCK */ |
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#define arch_spin_is_locked(lock) ((void)(lock), 0) |
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/* for sched/core.c and kernel_lock.c: */ |
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# define arch_spin_lock(lock) do { barrier(); (void)(lock); } while (0) |
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# define arch_spin_lock_flags(lock, flags) do { barrier(); (void)(lock); } while (0) |
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# define arch_spin_unlock(lock) do { barrier(); (void)(lock); } while (0) |
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# define arch_spin_trylock(lock) ({ barrier(); (void)(lock); 1; }) |
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#endif /* DEBUG_SPINLOCK */ |
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#define arch_spin_is_contended(lock) (((void)(lock), 0)) |
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#endif /* __LINUX_SPINLOCK_UP_H */
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