191 строка
4.4 KiB
C
191 строка
4.4 KiB
C
/* 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
|
|
|
|
#ifndef __ASSEMBLY__
|
|
|
|
#include <asm/psr.h>
|
|
|
|
#define __raw_spin_is_locked(lock) (*((volatile unsigned char *)(lock)) != 0)
|
|
|
|
#define __raw_spin_unlock_wait(lock) \
|
|
do { while (__raw_spin_is_locked(lock)) cpu_relax(); } while (0)
|
|
|
|
static inline void __raw_spin_lock(raw_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");
|
|
}
|
|
|
|
static inline int __raw_spin_trylock(raw_spinlock_t *lock)
|
|
{
|
|
unsigned int result;
|
|
__asm__ __volatile__("ldstub [%1], %0"
|
|
: "=r" (result)
|
|
: "r" (lock)
|
|
: "memory");
|
|
return (result == 0);
|
|
}
|
|
|
|
static inline void __raw_spin_unlock(raw_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
|
|
*
|
|
* Sort of like atomic_t's on Sparc, but even more clever.
|
|
*
|
|
* ------------------------------------
|
|
* | 24-bit counter | wlock | raw_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.
|
|
*/
|
|
static inline void __read_lock(raw_rwlock_t *rw)
|
|
{
|
|
register raw_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 __raw_read_lock(lock) \
|
|
do { unsigned long flags; \
|
|
local_irq_save(flags); \
|
|
__read_lock(lock); \
|
|
local_irq_restore(flags); \
|
|
} while(0)
|
|
|
|
static inline void __read_unlock(raw_rwlock_t *rw)
|
|
{
|
|
register raw_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 __raw_read_unlock(lock) \
|
|
do { unsigned long flags; \
|
|
local_irq_save(flags); \
|
|
__read_unlock(lock); \
|
|
local_irq_restore(flags); \
|
|
} while(0)
|
|
|
|
static inline void __raw_write_lock(raw_rwlock_t *rw)
|
|
{
|
|
register raw_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");
|
|
*(volatile __u32 *)&lp->lock = ~0U;
|
|
}
|
|
|
|
static inline int __raw_write_trylock(raw_rwlock_t *rw)
|
|
{
|
|
unsigned int val;
|
|
|
|
__asm__ __volatile__("ldstub [%1 + 3], %0"
|
|
: "=r" (val)
|
|
: "r" (&rw->lock)
|
|
: "memory");
|
|
|
|
if (val == 0) {
|
|
val = rw->lock & ~0xff;
|
|
if (val)
|
|
((volatile u8*)&rw->lock)[3] = 0;
|
|
else
|
|
*(volatile u32*)&rw->lock = ~0U;
|
|
}
|
|
|
|
return (val == 0);
|
|
}
|
|
|
|
static inline int __read_trylock(raw_rwlock_t *rw)
|
|
{
|
|
register raw_rwlock_t *lp asm("g1");
|
|
register int res asm("o0");
|
|
lp = rw;
|
|
__asm__ __volatile__(
|
|
"mov %%o7, %%g4\n\t"
|
|
"call ___rw_read_try\n\t"
|
|
" ldstub [%%g1 + 3], %%g2\n"
|
|
: "=r" (res)
|
|
: "r" (lp)
|
|
: "g2", "g4", "memory", "cc");
|
|
return res;
|
|
}
|
|
|
|
#define __raw_read_trylock(lock) \
|
|
({ unsigned long flags; \
|
|
int res; \
|
|
local_irq_save(flags); \
|
|
res = __read_trylock(lock); \
|
|
local_irq_restore(flags); \
|
|
res; \
|
|
})
|
|
|
|
#define __raw_write_unlock(rw) do { (rw)->lock = 0; } while(0)
|
|
|
|
#define __raw_spin_lock_flags(lock, flags) __raw_spin_lock(lock)
|
|
|
|
#define _raw_spin_relax(lock) cpu_relax()
|
|
#define _raw_read_relax(lock) cpu_relax()
|
|
#define _raw_write_relax(lock) cpu_relax()
|
|
|
|
#define __raw_read_can_lock(rw) (!((rw)->lock & 0xff))
|
|
#define __raw_write_can_lock(rw) (!(rw)->lock)
|
|
|
|
#endif /* !(__ASSEMBLY__) */
|
|
|
|
#endif /* __SPARC_SPINLOCK_H */
|