1 #ifndef __LINUX_SPINLOCK_UP_H
2 #define __LINUX_SPINLOCK_UP_H
4 #ifndef __LINUX_SPINLOCK_H
5 # error "please don't include this file directly"
8 #include <asm/processor.h> /* for cpu_relax() */
11 * include/linux/spinlock_up.h - UP-debug version of spinlocks.
13 * portions Copyright 2005, Red Hat, Inc., Ingo Molnar
14 * Released under the General Public License (GPL).
16 * In the debug case, 1 means unlocked, 0 means locked. (the values
17 * are inverted, to catch initialization bugs)
19 * No atomicity anywhere, we are on UP. However, we still need
20 * the compiler barriers, because we do not want the compiler to
21 * move potentially faulting instructions (notably user accesses)
22 * into the locked sequence, resulting in non-atomic execution.
25 #ifdef CONFIG_DEBUG_SPINLOCK
26 #define arch_spin_is_locked(x) ((x)->slock == 0)
28 static inline void arch_spin_lock(arch_spinlock_t *lock)
35 arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags)
37 local_irq_save(flags);
42 static inline int arch_spin_trylock(arch_spinlock_t *lock)
44 char oldval = lock->slock;
52 static inline void arch_spin_unlock(arch_spinlock_t *lock)
59 * Read-write spinlocks. No debug version.
61 #define arch_read_lock(lock) do { barrier(); (void)(lock); } while (0)
62 #define arch_write_lock(lock) do { barrier(); (void)(lock); } while (0)
63 #define arch_read_trylock(lock) ({ barrier(); (void)(lock); 1; })
64 #define arch_write_trylock(lock) ({ barrier(); (void)(lock); 1; })
65 #define arch_read_unlock(lock) do { barrier(); (void)(lock); } while (0)
66 #define arch_write_unlock(lock) do { barrier(); (void)(lock); } while (0)
68 #else /* DEBUG_SPINLOCK */
69 #define arch_spin_is_locked(lock) ((void)(lock), 0)
70 /* for sched.c and kernel_lock.c: */
71 # define arch_spin_lock(lock) do { barrier(); (void)(lock); } while (0)
72 # define arch_spin_lock_flags(lock, flags) do { barrier(); (void)(lock); } while (0)
73 # define arch_spin_unlock(lock) do { barrier(); (void)(lock); } while (0)
74 # define arch_spin_trylock(lock) ({ barrier(); (void)(lock); 1; })
75 #endif /* DEBUG_SPINLOCK */
77 #define arch_spin_is_contended(lock) (((void)(lock), 0))
79 #define arch_read_can_lock(lock) (((void)(lock), 1))
80 #define arch_write_can_lock(lock) (((void)(lock), 1))
82 #define arch_spin_unlock_wait(lock) \
83 do { cpu_relax(); } while (arch_spin_is_locked(lock))
85 #endif /* __LINUX_SPINLOCK_UP_H */