Viewing file:  spinlock.h (3.83 KB) -rw-r--r--
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#ifndef _ALPHA_SPINLOCK_H
#define _ALPHA_SPINLOCK_H
#include <linux/config.h>
#include <asm/system.h>
#include <linux/kernel.h>
#include <asm/current.h>
/*
* 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.
*/
typedef struct {
volatile unsigned int lock /*__attribute__((aligned(32))) */;
#if CONFIG_DEBUG_SPINLOCK
int on_cpu;
int line_no;
void *previous;
struct task_struct * task;
const char *base_file;
#endif
} spinlock_t;
#if CONFIG_DEBUG_SPINLOCK
#define SPIN_LOCK_UNLOCKED (spinlock_t) {0, -1, 0, 0, 0, 0}
#define spin_lock_init(x) \
((x)->lock = 0, (x)->on_cpu = -1, (x)->previous = 0, (x)->task = 0)
#else
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0 }
#define spin_lock_init(x) ((x)->lock = 0)
#endif
#define spin_is_locked(x) ((x)->lock != 0)
#define spin_unlock_wait(x) ({ do { barrier(); } while ((x)->lock); })
#if CONFIG_DEBUG_SPINLOCK
extern void spin_unlock(spinlock_t * lock);
extern void debug_spin_lock(spinlock_t * lock, const char *, int);
extern int debug_spin_trylock(spinlock_t * lock, const char *, int);
#define spin_lock(LOCK) debug_spin_lock(LOCK, __BASE_FILE__, __LINE__)
#define spin_trylock(LOCK) debug_spin_trylock(LOCK, __BASE_FILE__, __LINE__)
#define spin_lock_own(LOCK, LOCATION) \
do { \
if (!((LOCK)->lock && (LOCK)->on_cpu == smp_processor_id())) \
printk("%s: called on %d from %p but lock %s on %d\n", \
LOCATION, smp_processor_id(), \
__builtin_return_address(0), \
(LOCK)->lock ? "taken" : "freed", (LOCK)->on_cpu); \
} while (0)
#else
static inline void spin_unlock(spinlock_t * lock)
{
mb();
lock->lock = 0;
}
static inline void spin_lock(spinlock_t * lock)
{
long tmp;
/* Use sub-sections to put the actual loop at the end
of this object file's text section so as to perfect
branch prediction. */
__asm__ __volatile__(
"1: ldl_l %0,%1\n"
" blbs %0,2f\n"
" or %0,1,%0\n"
" stl_c %0,%1\n"
" beq %0,2f\n"
" mb\n"
".subsection 2\n"
"2: ldl %0,%1\n"
" blbs %0,2b\n"
" br 1b\n"
".previous"
: "=&r" (tmp), "=m" (lock->lock)
: "m"(lock->lock) : "memory");
}
#define spin_trylock(lock) (!test_and_set_bit(0,(lock)))
#define spin_lock_own(LOCK, LOCATION) ((void)0)
#endif /* CONFIG_DEBUG_SPINLOCK */
/***********************************************************/
typedef struct {
volatile int write_lock:1, read_counter:31;
} /*__attribute__((aligned(32)))*/ rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0 }
#define rwlock_init(x) do { *(x) = RW_LOCK_UNLOCKED; } while(0)
#if CONFIG_DEBUG_RWLOCK
extern void write_lock(rwlock_t * lock);
extern void read_lock(rwlock_t * lock);
#else
static inline void write_lock(rwlock_t * lock)
{
long regx;
__asm__ __volatile__(
"1: ldl_l %1,%0\n"
" bne %1,6f\n"
" or $31,1,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
" mb\n"
".subsection 2\n"
"6: ldl %1,%0\n"
" bne %1,6b\n"
" br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx)
: "0" (*(volatile int *)lock) : "memory");
}
static inline void read_lock(rwlock_t * lock)
{
long regx;
__asm__ __volatile__(
"1: ldl_l %1,%0\n"
" blbs %1,6f\n"
" subl %1,2,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
"4: mb\n"
".subsection 2\n"
"6: ldl %1,%0\n"
" blbs %1,6b\n"
" br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx)
: "m" (*(volatile int *)lock) : "memory");
}
#endif /* CONFIG_DEBUG_RWLOCK */
static inline void write_unlock(rwlock_t * lock)
{
mb();
*(volatile int *)lock = 0;
}
static inline void read_unlock(rwlock_t * lock)
{
long regx;
__asm__ __volatile__(
" mb\n"
"1: ldl_l %1,%0\n"
" addl %1,2,%1\n"
" stl_c %1,%0\n"
" beq %1,6f\n"
".subsection 2\n"
"6: br 1b\n"
".previous"
: "=m" (*(volatile int *)lock), "=&r" (regx)
: "m" (*(volatile int *)lock) : "memory");
}
#endif /* _ALPHA_SPINLOCK_H */
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