/* 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>
#include <linux/threads.h> /* For NR_CPUS */
#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 struct {
volatile unsigned char lock;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} spinlock_t;
#define SPIN_LOCK_UNLOCKED (spinlock_t) {0,}
#define spin_lock_init(lp) do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
#define spin_is_locked(lp) ((lp)->lock != 0)
#define spin_unlock_wait(lp) \
do { membar("#LoadLoad"); \
} while((lp)->lock)
static inline void _raw_spin_lock(spinlock_t *lock)
{
unsigned long tmp;
__asm__ __volatile__(
"1: ldstub [%1], %0\n"
" membar #StoreLoad | #StoreStore\n"
" brnz,pn %0, 2f\n"
" nop\n"
" .subsection 2\n"
"2: ldub [%1], %0\n"
" membar #LoadLoad\n"
" brnz,pt %0, 2b\n"
" nop\n"
" ba,a,pt %%xcc, 1b\n"
" .previous"
: "=&r" (tmp)
: "r" (lock)
: "memory");
}
static inline int _raw_spin_trylock(spinlock_t *lock)
{
unsigned long result;
__asm__ __volatile__(
" ldstub [%1], %0\n"
" membar #StoreLoad | #StoreStore"
: "=r" (result)
: "r" (lock)
: "memory");
return (result == 0UL);
}
static inline void _raw_spin_unlock(spinlock_t *lock)
{
__asm__ __volatile__(
" membar #StoreStore | #LoadStore\n"
" stb %%g0, [%0]"
: /* No outputs */
: "r" (lock)
: "memory");
}
static inline void _raw_spin_lock_flags(spinlock_t *lock, unsigned long flags)
{
unsigned long tmp1, tmp2;
__asm__ __volatile__(
"1: ldstub [%2], %0\n"
" membar #StoreLoad | #StoreStore\n"
" brnz,pn %0, 2f\n"
" nop\n"
" .subsection 2\n"
"2: rdpr %%pil, %1\n"
" wrpr %3, %%pil\n"
"3: ldub [%2], %0\n"
" membar #LoadLoad\n"
" brnz,pt %0, 3b\n"
" nop\n"
" ba,pt %%xcc, 1b\n"
" wrpr %1, %%pil\n"
" .previous"
: "=&r" (tmp1), "=&r" (tmp2)
: "r"(lock), "r"(flags)
: "memory");
}
#else /* !(CONFIG_DEBUG_SPINLOCK) */
typedef struct {
volatile unsigned char lock;
unsigned int owner_pc, owner_cpu;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} spinlock_t;
#define SPIN_LOCK_UNLOCKED (spinlock_t) { 0, 0, 0xff }
#define spin_lock_init(lp) do { *(lp)= SPIN_LOCK_UNLOCKED; } while(0)
#define spin_is_locked(__lock) ((__lock)->lock != 0)
#define spin_unlock_wait(__lock) \
do { \
membar("#LoadLoad"); \
} while((__lock)->lock)
extern void _do_spin_lock (spinlock_t *lock, char *str);
extern void _do_spin_unlock (spinlock_t *lock);
extern int _do_spin_trylock (spinlock_t *lock);
#define _raw_spin_trylock(lp) _do_spin_trylock(lp)
#define _raw_spin_lock(lock) _do_spin_lock(lock, "spin_lock")
#define _raw_spin_unlock(lock) _do_spin_unlock(lock)
#define _raw_spin_lock_flags(lock, flags) _raw_spin_lock(lock)
#endif /* CONFIG_DEBUG_SPINLOCK */
/* Multi-reader locks, these are much saner than the 32-bit Sparc ones... */
#ifndef CONFIG_DEBUG_SPINLOCK
typedef struct {
volatile unsigned int lock;
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) {0,}
#define rwlock_init(lp) do { *(lp) = RW_LOCK_UNLOCKED; } while(0)
static void inline __read_lock(rwlock_t *lock)
{
unsigned long tmp1, tmp2;
__asm__ __volatile__ (
"1: ldsw [%2], %0\n"
" brlz,pn %0, 2f\n"
"4: add %0, 1, %1\n"
" cas [%2], %0, %1\n"
" cmp %0, %1\n"
" membar #StoreLoad | #StoreStore\n"
" bne,pn %%icc, 1b\n"
" nop\n"
" .subsection 2\n"
"2: ldsw [%2], %0\n"
" membar #LoadLoad\n"
" brlz,pt %0, 2b\n"
" nop\n"
" ba,a,pt %%xcc, 4b\n"
" .previous"
: "=&r" (tmp1), "=&r" (tmp2)
: "r" (lock)
: "memory");
}
static void inline __read_unlock(rwlock_t *lock)
{
unsigned long tmp1, tmp2;
__asm__ __volatile__(
" membar #StoreLoad | #LoadLoad\n"
"1: lduw [%2], %0\n"
" sub %0, 1, %1\n"
" cas [%2], %0, %1\n"
" cmp %0, %1\n"
" bne,pn %%xcc, 1b\n"
" nop"
: "=&r" (tmp1), "=&r" (tmp2)
: "r" (lock)
: "memory");
}
static void inline __write_lock(rwlock_t *lock)
{
unsigned long mask, tmp1, tmp2;
mask = 0x80000000UL;
__asm__ __volatile__(
"1: lduw [%2], %0\n"
" brnz,pn %0, 2f\n"
"4: or %0, %3, %1\n"
" cas [%2], %0, %1\n"
" cmp %0, %1\n"
" membar #StoreLoad | #StoreStore\n"
" bne,pn %%icc, 1b\n"
" nop\n"
" .subsection 2\n"
"2: lduw [%2], %0\n"
" membar #LoadLoad\n"
" brnz,pt %0, 2b\n"
" nop\n"
" ba,a,pt %%xcc, 4b\n"
" .previous"
: "=&r" (tmp1), "=&r" (tmp2)
: "r" (lock), "r" (mask)
: "memory");
}
static void inline __write_unlock(rwlock_t *lock)
{
__asm__ __volatile__(
" membar #LoadStore | #StoreStore\n"
" stw %%g0, [%0]"
: /* no outputs */
: "r" (lock)
: "memory");
}
static int inline __write_trylock(rwlock_t *lock)
{
unsigned long mask, tmp1, tmp2, result;
mask = 0x80000000UL;
__asm__ __volatile__(
" mov 0, %2\n"
"1: lduw [%3], %0\n"
" brnz,pn %0, 2f\n"
" or %0, %4, %1\n"
" cas [%3], %0, %1\n"
" cmp %0, %1\n"
" membar #StoreLoad | #StoreStore\n"
" bne,pn %%icc, 1b\n"
" nop\n"
" mov 1, %2\n"
"2:"
: "=&r" (tmp1), "=&r" (tmp2), "=&r" (result)
: "r" (lock), "r" (mask)
: "memory");
return result;
}
#define _raw_read_lock(p) __read_lock(p)
#define _raw_read_unlock(p) __read_unlock(p)
#define _raw_write_lock(p) __write_lock(p)
#define _raw_write_unlock(p) __write_unlock(p)
#define _raw_write_trylock(p) __write_trylock(p)
#else /* !(CONFIG_DEBUG_SPINLOCK) */
typedef struct {
volatile unsigned long lock;
unsigned int writer_pc, writer_cpu;
unsigned int reader_pc[NR_CPUS];
#ifdef CONFIG_PREEMPT
unsigned int break_lock;
#endif
} rwlock_t;
#define RW_LOCK_UNLOCKED (rwlock_t) { 0, 0, 0xff, { } }
#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);
extern int _do_write_trylock(rwlock_t *rw, char *str);
#define _raw_read_lock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
_do_read_lock(lock, "read_lock"); \
local_irq_restore(flags); \
} while(0)
#define _raw_read_unlock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
_do_read_unlock(lock, "read_unlock"); \
local_irq_restore(flags); \
} while(0)
#define _raw_write_lock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
_do_write_lock(lock, "write_lock"); \
local_irq_restore(flags); \
} while(0)
#define _raw_write_unlock(lock) \
do { unsigned long flags; \
local_irq_save(flags); \
_do_write_unlock(lock); \
local_irq_restore(flags); \
} while(0)
#define _raw_write_trylock(lock) \
({ unsigned long flags; \
int val; \
local_irq_save(flags); \
val = _do_write_trylock(lock, "write_trylock"); \
local_irq_restore(flags); \
val; \
})
#endif /* CONFIG_DEBUG_SPINLOCK */
#define _raw_read_trylock(lock) generic_raw_read_trylock(lock)
#define read_can_lock(rw) (!((rw)->lock & 0x80000000UL))
#define write_can_lock(rw) (!(rw)->lock)
#endif /* !(__ASSEMBLY__) */
#endif /* !(__SPARC64_SPINLOCK_H) */
