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/* atomic.h: These still suck, but the I-cache hit rate is higher.
*
* Copyright (C) 1996 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
* Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
*
* Additions by Keith M Wesolowski (wesolows@foobazco.org) based
* on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
*/
#ifndef __ARCH_SPARC_ATOMIC__
#define __ARCH_SPARC_ATOMIC__
#include <linux/types.h>
typedef struct { volatile int counter; } atomic_t;
#ifdef __KERNEL__
/* Emulate cmpxchg() the same way we emulate atomics,
* by hashing the object address and indexing into an array
* of spinlocks to get a bit of performance...
*
* See arch/sparc/lib/atomic32.c for implementation.
*
* Cribbed from <asm-parisc/atomic.h>
*/
#define __HAVE_ARCH_CMPXCHG 1
/* bug catcher for when unsupported size is used - won't link */
extern void __cmpxchg_called_with_bad_pointer(void);
/* we only need to support cmpxchg of a u32 on sparc */
extern unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);
/* don't worry...optimizer will get rid of most of this */
static __inline__ unsigned long
__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)
{
switch(size) {
case 4:
return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
default:
__cmpxchg_called_with_bad_pointer();
break;
}
return old;
}
#define cmpxchg(ptr,o,n) ({ \
__typeof__(*(ptr)) _o_ = (o); \
__typeof__(*(ptr)) _n_ = (n); \
(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \
(unsigned long)_n_, sizeof(*(ptr))); \
})
#define ATOMIC_INIT(i) { (i) }
extern int __atomic_add_return(int, atomic_t *);
extern int atomic_cmpxchg(atomic_t *, int, int);
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
extern int atomic_add_unless(atomic_t *, int, int);
extern void atomic_set(atomic_t *, int);
#define atomic_read(v) ((v)->counter)
#define atomic_add(i, v) ((void)__atomic_add_return( (int)(i), (v)))
#define atomic_sub(i, v) ((void)__atomic_add_return(-(int)(i), (v)))
#define atomic_inc(v) ((void)__atomic_add_return( 1, (v)))
#define atomic_dec(v) ((void)__atomic_add_return( -1, (v)))
#define atomic_add_return(i, v) (__atomic_add_return( (int)(i), (v)))
#define atomic_sub_return(i, v) (__atomic_add_return(-(int)(i), (v)))
#define atomic_inc_return(v) (__atomic_add_return( 1, (v)))
#define atomic_dec_return(v) (__atomic_add_return( -1, (v)))
#define atomic_add_negative(a, v) (atomic_add_return((a), (v)) < 0)
/*
* atomic_inc_and_test - increment and test
* @v: pointer of type atomic_t
*
* Atomically increments @v by 1
* and returns true if the result is zero, or false for all
* other cases.
*/
#define atomic_inc_and_test(v) (atomic_inc_return(v) == 0)
#define atomic_dec_and_test(v) (atomic_dec_return(v) == 0)
#define atomic_sub_and_test(i, v) (atomic_sub_return(i, v) == 0)
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
/* This is the old 24-bit implementation. It's still used internally
* by some sparc-specific code, notably the semaphore implementation.
*/
typedef struct { volatile int counter; } atomic24_t;
#ifndef CONFIG_SMP
#define ATOMIC24_INIT(i) { (i) }
#define atomic24_read(v) ((v)->counter)
#define atomic24_set(v, i) (((v)->counter) = i)
#else
/* We do the bulk of the actual work out of line in two common
* routines in assembler, see arch/sparc/lib/atomic.S for the
* "fun" details.
*
* For SMP the trick is you embed the spin lock byte within
* the word, use the low byte so signedness is easily retained
* via a quick arithmetic shift. It looks like this:
*
* ----------------------------------------
* | signed 24-bit counter value | lock | atomic_t
* ----------------------------------------
* 31 8 7 0
*/
#define ATOMIC24_INIT(i) { ((i) << 8) }
static inline int atomic24_read(const atomic24_t *v)
{
int ret = v->counter;
while(ret & 0xff)
ret = v->counter;
return ret >> 8;
}
#define atomic24_set(v, i) (((v)->counter) = ((i) << 8))
#endif
static inline int __atomic24_add(int i, atomic24_t *v)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
register int tmp1 asm("g3");
register int tmp2 asm("g4");
register int tmp3 asm("g7");
ptr = &v->counter;
increment = i;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_add\n\t"
" add %%o7, 8, %%o7\n"
: "=&r" (increment), "=r" (tmp1), "=r" (tmp2), "=r" (tmp3)
: "0" (increment), "r" (ptr)
: "memory", "cc");
return increment;
}
static inline int __atomic24_sub(int i, atomic24_t *v)
{
register volatile int *ptr asm("g1");
register int increment asm("g2");
register int tmp1 asm("g3");
register int tmp2 asm("g4");
register int tmp3 asm("g7");
ptr = &v->counter;
increment = i;
__asm__ __volatile__(
"mov %%o7, %%g4\n\t"
"call ___atomic24_sub\n\t"
" add %%o7, 8, %%o7\n"
: "=&r" (increment), "=r" (tmp1), "=r" (tmp2), "=r" (tmp3)
: "0" (increment), "r" (ptr)
: "memory", "cc");
return increment;
}
#define atomic24_add(i, v) ((void)__atomic24_add((i), (v)))
#define atomic24_sub(i, v) ((void)__atomic24_sub((i), (v)))
#define atomic24_dec_return(v) __atomic24_sub(1, (v))
#define atomic24_inc_return(v) __atomic24_add(1, (v))
#define atomic24_sub_and_test(i, v) (__atomic24_sub((i), (v)) == 0)
#define atomic24_dec_and_test(v) (__atomic24_sub(1, (v)) == 0)
#define atomic24_inc(v) ((void)__atomic24_add(1, (v)))
#define atomic24_dec(v) ((void)__atomic24_sub(1, (v)))
#define atomic24_add_negative(i, v) (__atomic24_add((i), (v)) < 0)
/* Atomic operations are already serializing */
#define smp_mb__before_atomic_dec() barrier()
#define smp_mb__after_atomic_dec() barrier()
#define smp_mb__before_atomic_inc() barrier()
#define smp_mb__after_atomic_inc() barrier()
#endif /* !(__KERNEL__) */
#include <asm-generic/atomic.h>
#endif /* !(__ARCH_SPARC_ATOMIC__) */
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