diff options
Diffstat (limited to 'include/asm-parisc/spinlock.h')
| -rw-r--r-- | include/asm-parisc/spinlock.h | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/include/asm-parisc/spinlock.h b/include/asm-parisc/spinlock.h new file mode 100644 index 0000000..679ea1c --- /dev/null +++ b/include/asm-parisc/spinlock.h @@ -0,0 +1,258 @@ +#ifndef __ASM_SPINLOCK_H +#define __ASM_SPINLOCK_H + +#include <asm/system.h> + +/* Note that PA-RISC has to use `1' to mean unlocked and `0' to mean locked + * since it only has load-and-zero. Moreover, at least on some PA processors, + * the semaphore address has to be 16-byte aligned. + */ + +#ifndef CONFIG_DEBUG_SPINLOCK + +#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 } } +#undef SPIN_LOCK_UNLOCKED +#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED + +#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0) + +static inline int spin_is_locked(spinlock_t *x) +{ + volatile unsigned int *a = __ldcw_align(x); + return *a == 0; +} + +#define spin_unlock_wait(x) do { barrier(); } while(spin_is_locked(x)) +#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) + +static inline void _raw_spin_lock(spinlock_t *x) +{ + volatile unsigned int *a; + + mb(); + a = __ldcw_align(x); + while (__ldcw(a) == 0) + while (*a == 0); + mb(); +} + +static inline void _raw_spin_unlock(spinlock_t *x) +{ + volatile unsigned int *a; + mb(); + a = __ldcw_align(x); + *a = 1; + mb(); +} + +static inline int _raw_spin_trylock(spinlock_t *x) +{ + volatile unsigned int *a; + int ret; + + mb(); + a = __ldcw_align(x); + ret = __ldcw(a) != 0; + mb(); + + return ret; +} + +#define spin_lock_own(LOCK, LOCATION) ((void)0) + +#else /* !(CONFIG_DEBUG_SPINLOCK) */ + +#define SPINLOCK_MAGIC 0x1D244B3C + +#define __SPIN_LOCK_UNLOCKED { { 1, 1, 1, 1 }, SPINLOCK_MAGIC, 10, __FILE__ , NULL, 0, -1, NULL, NULL } +#undef SPIN_LOCK_UNLOCKED +#define SPIN_LOCK_UNLOCKED (spinlock_t) __SPIN_LOCK_UNLOCKED + +#define spin_lock_init(x) do { *(x) = SPIN_LOCK_UNLOCKED; } while(0) + +#define CHECK_LOCK(x) \ + do { \ + if (unlikely((x)->magic != SPINLOCK_MAGIC)) { \ + printk(KERN_ERR "%s:%d: spin_is_locked" \ + " on uninitialized spinlock %p.\n", \ + __FILE__, __LINE__, (x)); \ + } \ + } while(0) + +#define spin_is_locked(x) \ + ({ \ + CHECK_LOCK(x); \ + volatile unsigned int *a = __ldcw_align(x); \ + if (unlikely((*a == 0) && (x)->babble)) { \ + (x)->babble--; \ + printk("KERN_WARNING \ + %s:%d: spin_is_locked(%s/%p) already" \ + " locked by %s:%d in %s at %p(%d)\n", \ + __FILE__,__LINE__, (x)->module, (x), \ + (x)->bfile, (x)->bline, (x)->task->comm,\ + (x)->previous, (x)->oncpu); \ + } \ + *a == 0; \ + }) + +#define spin_unlock_wait(x) \ + do { \ + CHECK_LOCK(x); \ + volatile unsigned int *a = __ldcw_align(x); \ + if (unlikely((*a == 0) && (x)->babble)) { \ + (x)->babble--; \ + printk("KERN_WARNING \ + %s:%d: spin_unlock_wait(%s/%p)" \ + " owned by %s:%d in %s at %p(%d)\n", \ + __FILE__,__LINE__, (x)->module, (x), \ + (x)->bfile, (x)->bline, (x)->task->comm,\ + (x)->previous, (x)->oncpu); \ + } \ + barrier(); \ + } while (*((volatile unsigned char *)(__ldcw_align(x))) == 0) + +extern void _dbg_spin_lock(spinlock_t *lock, const char *base_file, int line_no); +extern void _dbg_spin_unlock(spinlock_t *lock, const char *, int); +extern int _dbg_spin_trylock(spinlock_t * lock, const char *, int); + +#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock) + +#define _raw_spin_unlock(lock) _dbg_spin_unlock(lock, __FILE__, __LINE__) +#define _raw_spin_lock(lock) _dbg_spin_lock(lock, __FILE__, __LINE__) +#define _raw_spin_trylock(lock) _dbg_spin_trylock(lock, __FILE__, __LINE__) + +/* just in case we need it */ +#define spin_lock_own(LOCK, LOCATION) \ +do { \ + volatile unsigned int *a = __ldcw_align(LOCK); \ + if (!((*a == 0) && ((LOCK)->oncpu == smp_processor_id()))) \ + printk("KERN_WARNING \ + %s: called on %d from %p but lock %s on %d\n", \ + LOCATION, smp_processor_id(), \ + __builtin_return_address(0), \ + (*a == 0) ? "taken" : "freed", (LOCK)->on_cpu); \ +} while (0) + +#endif /* !(CONFIG_DEBUG_SPINLOCK) */ + +/* + * Read-write spinlocks, allowing multiple readers + * but only one writer. + */ +typedef struct { + spinlock_t lock; + volatile int counter; +#ifdef CONFIG_PREEMPT + unsigned int break_lock; +#endif +} rwlock_t; + +#define RW_LOCK_UNLOCKED (rwlock_t) { __SPIN_LOCK_UNLOCKED, 0 } + +#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while (0) + +#define _raw_read_trylock(lock) generic_raw_read_trylock(lock) + +/* read_lock, read_unlock are pretty straightforward. Of course it somehow + * sucks we end up saving/restoring flags twice for read_lock_irqsave aso. */ + +#ifdef CONFIG_DEBUG_RWLOCK +extern void _dbg_read_lock(rwlock_t * rw, const char *bfile, int bline); +#define _raw_read_lock(rw) _dbg_read_lock(rw, __FILE__, __LINE__) +#else +static __inline__ void _raw_read_lock(rwlock_t *rw) +{ + unsigned long flags; + local_irq_save(flags); + _raw_spin_lock(&rw->lock); + + rw->counter++; + + _raw_spin_unlock(&rw->lock); + local_irq_restore(flags); +} +#endif /* CONFIG_DEBUG_RWLOCK */ + +static __inline__ void _raw_read_unlock(rwlock_t *rw) +{ + unsigned long flags; + local_irq_save(flags); + _raw_spin_lock(&rw->lock); + + rw->counter--; + + _raw_spin_unlock(&rw->lock); + local_irq_restore(flags); +} + +/* write_lock is less trivial. We optimistically grab the lock and check + * if we surprised any readers. If so we release the lock and wait till + * they're all gone before trying again + * + * Also note that we don't use the _irqsave / _irqrestore suffixes here. + * If we're called with interrupts enabled and we've got readers (or other + * writers) in interrupt handlers someone fucked up and we'd dead-lock + * sooner or later anyway. prumpf */ + +#ifdef CONFIG_DEBUG_RWLOCK +extern void _dbg_write_lock(rwlock_t * rw, const char *bfile, int bline); +#define _raw_write_lock(rw) _dbg_write_lock(rw, __FILE__, __LINE__) +#else +static __inline__ void _raw_write_lock(rwlock_t *rw) +{ +retry: + _raw_spin_lock(&rw->lock); + + if(rw->counter != 0) { + /* this basically never happens */ + _raw_spin_unlock(&rw->lock); + + while(rw->counter != 0); + + goto retry; + } + + /* got it. now leave without unlocking */ + rw->counter = -1; /* remember we are locked */ +} +#endif /* CONFIG_DEBUG_RWLOCK */ + +/* write_unlock is absolutely trivial - we don't have to wait for anything */ + +static __inline__ void _raw_write_unlock(rwlock_t *rw) +{ + rw->counter = 0; + _raw_spin_unlock(&rw->lock); +} + +#ifdef CONFIG_DEBUG_RWLOCK +extern int _dbg_write_trylock(rwlock_t * rw, const char *bfile, int bline); +#define _raw_write_trylock(rw) _dbg_write_trylock(rw, __FILE__, __LINE__) +#else +static __inline__ int _raw_write_trylock(rwlock_t *rw) +{ + _raw_spin_lock(&rw->lock); + if (rw->counter != 0) { + /* this basically never happens */ + _raw_spin_unlock(&rw->lock); + + return 0; + } + + /* got it. now leave without unlocking */ + rw->counter = -1; /* remember we are locked */ + return 1; +} +#endif /* CONFIG_DEBUG_RWLOCK */ + +static __inline__ int is_read_locked(rwlock_t *rw) +{ + return rw->counter > 0; +} + +static __inline__ int is_write_locked(rwlock_t *rw) +{ + return rw->counter < 0; +} + +#endif /* __ASM_SPINLOCK_H */ |
