#ifndef __ASM_SPINLOCK_H
#define __ASM_SPINLOCK_H
+#include <linux/smp.h>
+
+#if __GNUC__ > 3 || (__GNUC__ == 3 && __GNUC_MINOR__ > 2)
+
static inline int
_raw_compare_and_swap(volatile unsigned int *lock,
unsigned int old, unsigned int new)
{
- asm volatile ("cs %0,%3,0(%4)"
- : "=d" (old), "=m" (*lock)
- : "0" (old), "d" (new), "a" (lock), "m" (*lock)
- : "cc", "memory" );
+ asm volatile(
+ " cs %0,%3,%1"
+ : "=d" (old), "=Q" (*lock)
+ : "0" (old), "d" (new), "Q" (*lock)
+ : "cc", "memory" );
return old;
}
+#else /* __GNUC__ */
+
+static inline int
+_raw_compare_and_swap(volatile unsigned int *lock,
+ unsigned int old, unsigned int new)
+{
+ asm volatile(
+ " cs %0,%3,0(%4)"
+ : "=d" (old), "=m" (*lock)
+ : "0" (old), "d" (new), "a" (lock), "m" (*lock)
+ : "cc", "memory" );
+ return old;
+}
+
+#endif /* __GNUC__ */
+
/*
* Simple spin lock operations. There are two variants, one clears IRQ's
* on the local processor, one does not.
*
* We make no fairness assumptions. They have a cost.
+ *
+ * (the type definitions are in asm/spinlock_types.h)
*/
-typedef struct {
- volatile unsigned int lock;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} __attribute__ ((aligned (4))) spinlock_t;
-
-#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
-#define spin_lock_init(lp) do { (lp)->lock = 0; } while(0)
-#define spin_unlock_wait(lp) do { barrier(); } while(((volatile spinlock_t *)(lp))->lock)
-#define spin_is_locked(x) ((x)->lock != 0)
-#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
+#define __raw_spin_is_locked(x) ((x)->owner_cpu != 0)
+#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
+#define __raw_spin_unlock_wait(lock) \
+ do { while (__raw_spin_is_locked(lock)) \
+ _raw_spin_relax(lock); } while (0)
-extern void _raw_spin_lock_wait(spinlock_t *lp, unsigned int pc);
-extern int _raw_spin_trylock_retry(spinlock_t *lp, unsigned int pc);
+extern void _raw_spin_lock_wait(raw_spinlock_t *, unsigned int pc);
+extern int _raw_spin_trylock_retry(raw_spinlock_t *, unsigned int pc);
+extern void _raw_spin_relax(raw_spinlock_t *lock);
-static inline void _raw_spin_lock(spinlock_t *lp)
+static inline void __raw_spin_lock(raw_spinlock_t *lp)
{
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
-
- if (unlikely(_raw_compare_and_swap(&lp->lock, 0, pc) != 0))
- _raw_spin_lock_wait(lp, pc);
+ int old;
+
+ old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+ if (likely(old == 0)) {
+ lp->owner_pc = pc;
+ return;
+ }
+ _raw_spin_lock_wait(lp, pc);
}
-static inline int _raw_spin_trylock(spinlock_t *lp)
+static inline int __raw_spin_trylock(raw_spinlock_t *lp)
{
unsigned long pc = 1 | (unsigned long) __builtin_return_address(0);
+ int old;
- if (likely(_raw_compare_and_swap(&lp->lock, 0, pc) == 0))
+ old = _raw_compare_and_swap(&lp->owner_cpu, 0, ~smp_processor_id());
+ if (likely(old == 0)) {
+ lp->owner_pc = pc;
return 1;
+ }
return _raw_spin_trylock_retry(lp, pc);
}
-static inline void _raw_spin_unlock(spinlock_t *lp)
+static inline void __raw_spin_unlock(raw_spinlock_t *lp)
{
- _raw_compare_and_swap(&lp->lock, lp->lock, 0);
+ lp->owner_pc = 0;
+ _raw_compare_and_swap(&lp->owner_cpu, lp->owner_cpu, 0);
}
/*
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*/
-typedef struct {
- volatile unsigned int lock;
- volatile unsigned long owner_pc;
-#ifdef CONFIG_PREEMPT
- unsigned int break_lock;
-#endif
-} rwlock_t;
-
-#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
-
-#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
/**
* read_can_lock - would read_trylock() succeed?
* @lock: the rwlock in question.
*/
-#define read_can_lock(x) ((int)(x)->lock >= 0)
+#define __raw_read_can_lock(x) ((int)(x)->lock >= 0)
/**
* write_can_lock - would write_trylock() succeed?
* @lock: the rwlock in question.
*/
-#define write_can_lock(x) ((x)->lock == 0)
+#define __raw_write_can_lock(x) ((x)->lock == 0)
-extern void _raw_read_lock_wait(rwlock_t *lp);
-extern int _raw_read_trylock_retry(rwlock_t *lp);
-extern void _raw_write_lock_wait(rwlock_t *lp);
-extern int _raw_write_trylock_retry(rwlock_t *lp);
+extern void _raw_read_lock_wait(raw_rwlock_t *lp);
+extern int _raw_read_trylock_retry(raw_rwlock_t *lp);
+extern void _raw_write_lock_wait(raw_rwlock_t *lp);
+extern int _raw_write_trylock_retry(raw_rwlock_t *lp);
-static inline void _raw_read_lock(rwlock_t *rw)
+static inline void __raw_read_lock(raw_rwlock_t *rw)
{
unsigned int old;
old = rw->lock & 0x7fffffffU;
_raw_read_lock_wait(rw);
}
-static inline void _raw_read_unlock(rwlock_t *rw)
+static inline void __raw_read_unlock(raw_rwlock_t *rw)
{
unsigned int old, cmp;
} while (cmp != old);
}
-static inline void _raw_write_lock(rwlock_t *rw)
+static inline void __raw_write_lock(raw_rwlock_t *rw)
{
if (unlikely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) != 0))
_raw_write_lock_wait(rw);
}
-static inline void _raw_write_unlock(rwlock_t *rw)
+static inline void __raw_write_unlock(raw_rwlock_t *rw)
{
_raw_compare_and_swap(&rw->lock, 0x80000000, 0);
}
-static inline int _raw_read_trylock(rwlock_t *rw)
+static inline int __raw_read_trylock(raw_rwlock_t *rw)
{
unsigned int old;
old = rw->lock & 0x7fffffffU;
return _raw_read_trylock_retry(rw);
}
-static inline int _raw_write_trylock(rwlock_t *rw)
+static inline int __raw_write_trylock(raw_rwlock_t *rw)
{
if (likely(_raw_compare_and_swap(&rw->lock, 0, 0x80000000) == 0))
return 1;
return _raw_write_trylock_retry(rw);
}
+#define _raw_read_relax(lock) cpu_relax()
+#define _raw_write_relax(lock) cpu_relax()
+
#endif /* __ASM_SPINLOCK_H */