mirror of
https://github.com/torvalds/linux.git
synced 2024-10-31 09:11:49 +00:00
1da177e4c3
Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
259 lines
6.7 KiB
C
259 lines
6.7 KiB
C
#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 */
|