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