1 #ifndef __LINUX_SPINLOCK_UP_H 2 #define __LINUX_SPINLOCK_UP_H 3 4 #ifndef __LINUX_SPINLOCK_H 5 # error "please don't include this file directly" 6 #endif 7 8 #include <asm/processor.h> /* for cpu_relax() */ 9 10 /* 11 * include/linux/spinlock_up.h - UP-debug version of spinlocks. 12 * 13 * portions Copyright 2005, Red Hat, Inc., Ingo Molnar 14 * Released under the General Public License (GPL). 15 * 16 * In the debug case, 1 means unlocked, 0 means locked. (the values 17 * are inverted, to catch initialization bugs) 18 * 19 * No atomicity anywhere, we are on UP. 20 */ 21 22 #ifdef CONFIG_DEBUG_SPINLOCK 23 #define arch_spin_is_locked(x) ((x)->slock == 0) 24 25 static inline void arch_spin_lock(arch_spinlock_t *lock) 26 { 27 lock->slock = 0; 28 } 29 30 static inline void 31 arch_spin_lock_flags(arch_spinlock_t *lock, unsigned long flags) 32 { 33 local_irq_save(flags); 34 lock->slock = 0; 35 } 36 37 static inline int arch_spin_trylock(arch_spinlock_t *lock) 38 { 39 char oldval = lock->slock; 40 41 lock->slock = 0; 42 43 return oldval > 0; 44 } 45 46 static inline void arch_spin_unlock(arch_spinlock_t *lock) 47 { 48 lock->slock = 1; 49 } 50 51 /* 52 * Read-write spinlocks. No debug version. 53 */ 54 #define arch_read_lock(lock) do { (void)(lock); } while (0) 55 #define arch_write_lock(lock) do { (void)(lock); } while (0) 56 #define arch_read_trylock(lock) ({ (void)(lock); 1; }) 57 #define arch_write_trylock(lock) ({ (void)(lock); 1; }) 58 #define arch_read_unlock(lock) do { (void)(lock); } while (0) 59 #define arch_write_unlock(lock) do { (void)(lock); } while (0) 60 61 #else /* DEBUG_SPINLOCK */ 62 #define arch_spin_is_locked(lock) ((void)(lock), 0) 63 /* for sched.c and kernel_lock.c: */ 64 # define arch_spin_lock(lock) do { (void)(lock); } while (0) 65 # define arch_spin_lock_flags(lock, flags) do { (void)(lock); } while (0) 66 # define arch_spin_unlock(lock) do { (void)(lock); } while (0) 67 # define arch_spin_trylock(lock) ({ (void)(lock); 1; }) 68 #endif /* DEBUG_SPINLOCK */ 69 70 #define arch_spin_is_contended(lock) (((void)(lock), 0)) 71 72 #define arch_read_can_lock(lock) (((void)(lock), 1)) 73 #define arch_write_can_lock(lock) (((void)(lock), 1)) 74 75 #define arch_spin_unlock_wait(lock) \ 76 do { cpu_relax(); } while (arch_spin_is_locked(lock)) 77 78 #endif /* __LINUX_SPINLOCK_UP_H */ 79