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/* spinlock.h: 32-bit Sparc spinlock support.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
*/
#ifndef __SPARC_SPINLOCK_H
#define __SPARC_SPINLOCK_H
#include <linux/threads.h> /* For NR_CPUS */
#ifndef __ASSEMBLY__
#include <asm/psr.h>
/*
* Define this to use the verbose/debugging versions in
* arch/sparc/lib/debuglocks.c
*
* Be sure to make dep whenever changing this option.
*/
#define SPIN_LOCK_DEBUG
#ifdef SPIN_LOCK_DEBUG
struct _spinlock_debug {
unsigned char lock;
unsigned long owner_pc;
};
typedef struct _spinlock_debug spinlock_t;
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0 }
#define spin_lock_init(lp) do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
#define spin_is_locked(lp) (*((volatile unsigned char *)(&((lp)->lock))) != 0)
#define spin_unlock_wait(lp) do { barrier(); } while(*(volatile unsigned char *)(&(lp)->lock))
extern void _do_spin_lock(spinlock_t *lock, char *str);
extern int _spin_trylock(spinlock_t *lock);
extern void _do_spin_unlock(spinlock_t *lock);
#define spin_trylock(lp) _spin_trylock(lp)
#define spin_lock(lock) _do_spin_lock(lock, "spin_lock")
#define spin_unlock(lock) _do_spin_unlock(lock)
struct _rwlock_debug {
volatile unsigned int lock;
unsigned long owner_pc;
unsigned long reader_pc[NR_CPUS];
};
typedef struct _rwlock_debug rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, {0} }
#define rwlock_init(lp) do { *(lp)= RW_LOCK_UNLOCKED; } while(0)
extern void _do_read_lock(rwlock_t *rw, char *str);
extern void _do_read_unlock(rwlock_t *rw, char *str);
extern void _do_write_lock(rwlock_t *rw, char *str);
extern void _do_write_unlock(rwlock_t *rw);
#define read_lock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_read_lock(lock, "read_lock"); \
__restore_flags(flags); \
} while(0)
#define read_unlock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_read_unlock(lock, "read_unlock"); \
__restore_flags(flags); \
} while(0)
#define write_lock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_write_lock(lock, "write_lock"); \
__restore_flags(flags); \
} while(0)
#define write_unlock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_do_write_unlock(lock); \
__restore_flags(flags); \
} while(0)
#else /* !SPIN_LOCK_DEBUG */
typedef unsigned char spinlock_t;
#define SPIN_LOCK_UNLOCKED 0
#define spin_lock_init(lock) (*((unsigned char *)(lock)) = 0)
#define spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
#define spin_unlock_wait(lock) \
do { \
barrier(); \
} while(*((volatile unsigned char *)lock))
extern __inline__ void spin_lock(spinlock_t *lock)
{
__asm__ __volatile__(
"\n1:\n\t"
"ldstub [%0], %%g2\n\t"
"orcc %%g2, 0x0, %%g0\n\t"
"bne,a 2f\n\t"
" ldub [%0], %%g2\n\t"
".subsection 2\n"
"2:\n\t"
"orcc %%g2, 0x0, %%g0\n\t"
"bne,a 2b\n\t"
" ldub [%0], %%g2\n\t"
"b,a 1b\n\t"
".previous\n"
: /* no outputs */
: "r" (lock)
: "g2", "memory", "cc");
}
extern __inline__ int spin_trylock(spinlock_t *lock)
{
unsigned int result;
__asm__ __volatile__("ldstub [%1], %0"
: "=r" (result)
: "r" (lock)
: "memory");
return (result == 0);
}
extern __inline__ void spin_unlock(spinlock_t *lock)
{
__asm__ __volatile__("stb %%g0, [%0]" : : "r" (lock) : "memory");
}
/* Read-write spinlocks, allowing multiple readers
* but only one writer.
*
* NOTE! it is quite common to have readers in interrupts
* but no interrupt writers. For those circumstances we
* can "mix" irq-safe locks - any writer needs to get a
* irq-safe write-lock, but readers can get non-irqsafe
* read-locks.
*
* XXX This might create some problems with my dual spinlock
* XXX scheme, deadlocks etc. -DaveM
*/
typedef struct { volatile unsigned int lock; } rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0 }
#define rwlock_init(lp) do { *(lp)= RW_LOCK_UNLOCKED; } while(0)
/* Sort of like atomic_t's on Sparc, but even more clever.
*
* ------------------------------------
* | 24-bit counter | wlock | rwlock_t
* ------------------------------------
* 31 8 7 0
*
* wlock signifies the one writer is in or somebody is updating
* counter. For a writer, if he successfully acquires the wlock,
* but counter is non-zero, he has to release the lock and wait,
* till both counter and wlock are zero.
*
* Unfortunately this scheme limits us to ~16,000,000 cpus.
*/
extern __inline__ void _read_lock(rwlock_t *rw)
{
register rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___rw_read_enter\n\t"
" ldstub [%%g1 + 3], %%g2\n"
: /* no outputs */
: "r" (lp)
: "g2", "g4", "memory", "cc");
}
#define read_lock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_read_lock(lock); \
__restore_flags(flags); \
} while(0)
extern __inline__ void _read_unlock(rwlock_t *rw)
{
register rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___rw_read_exit\n\t"
" ldstub [%%g1 + 3], %%g2\n"
: /* no outputs */
: "r" (lp)
: "g2", "g4", "memory", "cc");
}
#define read_unlock(lock) \
do { unsigned long flags; \
__save_and_cli(flags); \
_read_unlock(lock); \
__restore_flags(flags); \
} while(0)
extern __inline__ void write_lock(rwlock_t *rw)
{
register rwlock_t *lp asm("g1");
lp = rw;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___rw_write_enter\n\t"
" ldstub [%%g1 + 3], %%g2\n"
: /* no outputs */
: "r" (lp)
: "g2", "g4", "memory", "cc");
}
#define write_unlock(rw) do { (rw)->lock = 0; } while(0)
#endif /* SPIN_LOCK_DEBUG */
#endif /* !(__ASSEMBLY__) */
#endif /* __SPARC_SPINLOCK_H */
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