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/* spinlock.h: 64-bit Sparc spinlock support.
*
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
*/
#ifndef __SPARC64_SPINLOCK_H
#define __SPARC64_SPINLOCK_H
#include <linux/config.h>
#ifndef __ASSEMBLY__
/* To get debugging spinlocks which detect and catch
* deadlock situations, set CONFIG_DEBUG_SPINLOCK
* and rebuild your kernel.
*/
/* All of these locking primitives are expected to work properly
* even in an RMO memory model, which currently is what the kernel
* runs in.
*
* There is another issue. Because we play games to save cycles
* in the non-contention case, we need to be extra careful about
* branch targets into the "spinning" code. They live in their
* own section, but the newer V9 branches have a shorter range
* than the traditional 32-bit sparc branch variants. The rule
* is that the branches that go into and out of the spinner sections
* must be pre-V9 branches.
*/
#ifndef CONFIG_DEBUG_SPINLOCK
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 { membar("#LoadLoad"); \
} while(*((volatile unsigned char *)lock))
extern __inline__ void spin_lock(spinlock_t *lock)
{
__asm__ __volatile__(
"1: ldstub [%0], %%g7\n"
" brnz,pn %%g7, 2f\n"
" membar #StoreLoad | #StoreStore\n"
" .subsection 2\n"
"2: ldub [%0], %%g7\n"
" brnz,pt %%g7, 2b\n"
" membar #LoadLoad\n"
" b,a,pt %%xcc, 1b\n"
" .previous\n"
: /* no outputs */
: "r" (lock)
: "g7", "memory");
}
extern __inline__ int spin_trylock(spinlock_t *lock)
{
unsigned int result;
__asm__ __volatile__("ldstub [%1], %0\n\t"
"membar #StoreLoad | #StoreStore"
: "=r" (result)
: "r" (lock)
: "memory");
return (result == 0);
}
extern __inline__ void spin_unlock(spinlock_t *lock)
{
__asm__ __volatile__("membar #StoreStore | #LoadStore\n\t"
"stb %%g0, [%0]"
: /* No outputs */
: "r" (lock)
: "memory");
}
#else /* !(CONFIG_DEBUG_SPINLOCK) */
typedef struct {
unsigned char lock;
unsigned int owner_pc, owner_cpu;
} spinlock_t;
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
#define spin_lock_init(__lock) \
do { (__lock)->lock = 0; \
(__lock)->owner_pc = 0; \
(__lock)->owner_cpu = 0xff; \
} while(0)
#define spin_is_locked(__lock) (*((volatile unsigned char *)(&((__lock)->lock))) != 0)
#define spin_unlock_wait(__lock) \
do { \
membar("#LoadLoad"); \
} while(*((volatile unsigned char *)(&((__lock)->lock))))
extern void _do_spin_lock (spinlock_t *lock, char *str);
extern void _do_spin_unlock (spinlock_t *lock);
extern int _spin_trylock (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)
#endif /* CONFIG_DEBUG_SPINLOCK */
/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
#ifndef CONFIG_DEBUG_SPINLOCK
typedef unsigned int rwlock_t;
#define RW_LOCK_UNLOCKED 0
#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
extern void __read_lock(rwlock_t *);
extern void __read_unlock(rwlock_t *);
extern void __write_lock(rwlock_t *);
extern void __write_unlock(rwlock_t *);
#define read_lock(p) __read_lock(p)
#define read_unlock(p) __read_unlock(p)
#define write_lock(p) __write_lock(p)
#define write_unlock(p) __write_unlock(p)
#else /* !(CONFIG_DEBUG_SPINLOCK) */
typedef struct {
unsigned long lock;
unsigned int writer_pc, writer_cpu;
unsigned int reader_pc[4];
} rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, 0xff, { 0, 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)
#endif /* CONFIG_DEBUG_SPINLOCK */
#endif /* !(__ASSEMBLY__) */
#endif /* !(__SPARC64_SPINLOCK_H) */
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