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#ifndef _SPARC64_SEMAPHORE_H
#define _SPARC64_SEMAPHORE_H
/* These are actually reasonable on the V9.
*
* See asm-ppc/semaphore.h for implementation commentary,
* only sparc64 specific issues are commented here.
*/
#ifdef __KERNEL__
#include <asm/atomic.h>
#include <asm/system.h>
#include <linux/wait.h>
#include <linux/rwsem.h>
struct semaphore {
atomic_t count;
wait_queue_head_t wait;
};
#define __SEMAPHORE_INITIALIZER(name, count) \
{ ATOMIC_INIT(count), \
__WAIT_QUEUE_HEAD_INITIALIZER((name).wait) }
#define __MUTEX_INITIALIZER(name) \
__SEMAPHORE_INITIALIZER(name, 1)
#define __DECLARE_SEMAPHORE_GENERIC(name, count) \
struct semaphore name = __SEMAPHORE_INITIALIZER(name,count)
#define DECLARE_MUTEX(name) __DECLARE_SEMAPHORE_GENERIC(name, 1)
#define DECLARE_MUTEX_LOCKED(name) __DECLARE_SEMAPHORE_GENERIC(name, 0)
static inline void sema_init (struct semaphore *sem, int val)
{
atomic_set(&sem->count, val);
init_waitqueue_head(&sem->wait);
}
static inline void init_MUTEX (struct semaphore *sem)
{
sema_init(sem, 1);
}
static inline void init_MUTEX_LOCKED (struct semaphore *sem)
{
sema_init(sem, 0);
}
extern void __down(struct semaphore * sem);
extern int __down_interruptible(struct semaphore * sem);
extern void __up(struct semaphore * sem);
static __inline__ void down(struct semaphore * sem)
{
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count - 1;
* sem->count = new_val;
* if (old_val < 1)
* __down(sem);
*
* The (old_val < 1) test is equivalent to
* the more straightforward (new_val < 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! down sem(%0)\n"
"1: lduw [%0], %%g5\n"
" sub %%g5, 1, %%g7\n"
" cas [%0], %%g5, %%g7\n"
" cmp %%g5, %%g7\n"
" bne,pn %%icc, 1b\n"
" cmp %%g7, 1\n"
" bl,pn %%icc, 3f\n"
" membar #StoreStore\n"
"2:\n"
" .subsection 2\n"
"3: mov %0, %%g5\n"
" save %%sp, -160, %%sp\n"
" mov %%g1, %%l1\n"
" mov %%g2, %%l2\n"
" mov %%g3, %%l3\n"
" call %1\n"
" mov %%g5, %%o0\n"
" mov %%l1, %%g1\n"
" mov %%l2, %%g2\n"
" ba,pt %%xcc, 2b\n"
" restore %%l3, %%g0, %%g3\n"
" .previous\n"
: : "r" (sem), "i" (__down)
: "g5", "g7", "memory", "cc");
}
static __inline__ int down_interruptible(struct semaphore *sem)
{
int ret = 0;
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count - 1;
* sem->count = new_val;
* if (old_val < 1)
* ret = __down_interruptible(sem);
*
* The (old_val < 1) test is equivalent to
* the more straightforward (new_val < 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! down_interruptible sem(%2) ret(%0)\n"
"1: lduw [%2], %%g5\n"
" sub %%g5, 1, %%g7\n"
" cas [%2], %%g5, %%g7\n"
" cmp %%g5, %%g7\n"
" bne,pn %%icc, 1b\n"
" cmp %%g7, 1\n"
" bl,pn %%icc, 3f\n"
" membar #StoreStore\n"
"2:\n"
" .subsection 2\n"
"3: mov %2, %%g5\n"
" save %%sp, -160, %%sp\n"
" mov %%g1, %%l1\n"
" mov %%g2, %%l2\n"
" mov %%g3, %%l3\n"
" call %3\n"
" mov %%g5, %%o0\n"
" mov %%l1, %%g1\n"
" mov %%l2, %%g2\n"
" mov %%l3, %%g3\n"
" ba,pt %%xcc, 2b\n"
" restore %%o0, %%g0, %0\n"
" .previous\n"
: "=r" (ret)
: "0" (ret), "r" (sem), "i" (__down_interruptible)
: "g5", "g7", "memory", "cc");
return ret;
}
static __inline__ int down_trylock(struct semaphore *sem)
{
int ret;
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count - 1;
* if (old_val < 1) {
* ret = 1;
* } else {
* sem->count = new_val;
* ret = 0;
* }
*
* The (old_val < 1) test is equivalent to
* the more straightforward (new_val < 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! down_trylock sem(%1) ret(%0)\n"
"1: lduw [%1], %%g5\n"
" sub %%g5, 1, %%g7\n"
" cmp %%g5, 1\n"
" bl,pn %%icc, 2f\n"
" mov 1, %0\n"
" cas [%1], %%g5, %%g7\n"
" cmp %%g5, %%g7\n"
" bne,pn %%icc, 1b\n"
" mov 0, %0\n"
" membar #StoreStore\n"
"2:\n"
: "=&r" (ret)
: "r" (sem)
: "g5", "g7", "memory", "cc");
return ret;
}
static __inline__ void up(struct semaphore * sem)
{
/* This atomically does:
* old_val = sem->count;
* new_val = sem->count + 1;
* sem->count = new_val;
* if (old_val < 0)
* __up(sem);
*
* The (old_val < 0) test is equivalent to
* the more straightforward (new_val <= 0),
* but it is easier to test the former because
* of how the CAS instruction works.
*/
__asm__ __volatile__("\n"
" ! up sem(%0)\n"
" membar #StoreLoad | #LoadLoad\n"
"1: lduw [%0], %%g5\n"
" add %%g5, 1, %%g7\n"
" cas [%0], %%g5, %%g7\n"
" cmp %%g5, %%g7\n"
" bne,pn %%icc, 1b\n"
" addcc %%g7, 1, %%g0\n"
" ble,pn %%icc, 3f\n"
" nop\n"
"2:\n"
" .subsection 2\n"
"3: mov %0, %%g5\n"
" save %%sp, -160, %%sp\n"
" mov %%g1, %%l1\n"
" mov %%g2, %%l2\n"
" mov %%g3, %%l3\n"
" call %1\n"
" mov %%g5, %%o0\n"
" mov %%l1, %%g1\n"
" mov %%l2, %%g2\n"
" ba,pt %%xcc, 2b\n"
" restore %%l3, %%g0, %%g3\n"
" .previous\n"
: : "r" (sem), "i" (__up)
: "g5", "g7", "memory", "cc");
}
#endif /* __KERNEL__ */
#endif /* !(_SPARC64_SEMAPHORE_H) */
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