kernel-ark/include/asm-ia64/atomic.h
Nick Piggin 0b2fcfdb8b [PATCH] atomic: add_unless cmpxchg optimise
Without branch hints, the very unlikely chance of the loop repeating due to
cmpxchg failure is unrolled with gcc-4 that I have tested.

Improve this for architectures with a native cas/cmpxchg.  llsc archs
should try to implement this natively.

Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Andi Kleen <ak@muc.de>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-03-23 07:38:17 -08:00

204 lines
5.8 KiB
C

#ifndef _ASM_IA64_ATOMIC_H
#define _ASM_IA64_ATOMIC_H
/*
* Atomic operations that C can't guarantee us. Useful for
* resource counting etc..
*
* NOTE: don't mess with the types below! The "unsigned long" and
* "int" types were carefully placed so as to ensure proper operation
* of the macros.
*
* Copyright (C) 1998, 1999, 2002-2003 Hewlett-Packard Co
* David Mosberger-Tang <davidm@hpl.hp.com>
*/
#include <linux/types.h>
#include <asm/intrinsics.h>
/*
* On IA-64, counter must always be volatile to ensure that that the
* memory accesses are ordered.
*/
typedef struct { volatile __s32 counter; } atomic_t;
typedef struct { volatile __s64 counter; } atomic64_t;
#define ATOMIC_INIT(i) ((atomic_t) { (i) })
#define ATOMIC64_INIT(i) ((atomic64_t) { (i) })
#define atomic_read(v) ((v)->counter)
#define atomic64_read(v) ((v)->counter)
#define atomic_set(v,i) (((v)->counter) = (i))
#define atomic64_set(v,i) (((v)->counter) = (i))
static __inline__ int
ia64_atomic_add (int i, atomic_t *v)
{
__s32 old, new;
CMPXCHG_BUGCHECK_DECL
do {
CMPXCHG_BUGCHECK(v);
old = atomic_read(v);
new = old + i;
} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic_t)) != old);
return new;
}
static __inline__ int
ia64_atomic64_add (__s64 i, atomic64_t *v)
{
__s64 old, new;
CMPXCHG_BUGCHECK_DECL
do {
CMPXCHG_BUGCHECK(v);
old = atomic_read(v);
new = old + i;
} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic64_t)) != old);
return new;
}
static __inline__ int
ia64_atomic_sub (int i, atomic_t *v)
{
__s32 old, new;
CMPXCHG_BUGCHECK_DECL
do {
CMPXCHG_BUGCHECK(v);
old = atomic_read(v);
new = old - i;
} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic_t)) != old);
return new;
}
static __inline__ int
ia64_atomic64_sub (__s64 i, atomic64_t *v)
{
__s64 old, new;
CMPXCHG_BUGCHECK_DECL
do {
CMPXCHG_BUGCHECK(v);
old = atomic_read(v);
new = old - i;
} while (ia64_cmpxchg(acq, v, old, new, sizeof(atomic64_t)) != old);
return new;
}
#define atomic_cmpxchg(v, old, new) ((int)cmpxchg(&((v)->counter), old, new))
#define atomic_xchg(v, new) (xchg(&((v)->counter), new))
#define atomic_add_unless(v, a, u) \
({ \
int c, old; \
c = atomic_read(v); \
for (;;) { \
if (unlikely(c == (u))) \
break; \
old = atomic_cmpxchg((v), c, c + (a)); \
if (likely(old == c)) \
break; \
c = old; \
} \
c != (u); \
})
#define atomic_inc_not_zero(v) atomic_add_unless((v), 1, 0)
#define atomic_add_return(i,v) \
({ \
int __ia64_aar_i = (i); \
(__builtin_constant_p(i) \
&& ( (__ia64_aar_i == 1) || (__ia64_aar_i == 4) \
|| (__ia64_aar_i == 8) || (__ia64_aar_i == 16) \
|| (__ia64_aar_i == -1) || (__ia64_aar_i == -4) \
|| (__ia64_aar_i == -8) || (__ia64_aar_i == -16))) \
? ia64_fetch_and_add(__ia64_aar_i, &(v)->counter) \
: ia64_atomic_add(__ia64_aar_i, v); \
})
#define atomic64_add_return(i,v) \
({ \
long __ia64_aar_i = (i); \
(__builtin_constant_p(i) \
&& ( (__ia64_aar_i == 1) || (__ia64_aar_i == 4) \
|| (__ia64_aar_i == 8) || (__ia64_aar_i == 16) \
|| (__ia64_aar_i == -1) || (__ia64_aar_i == -4) \
|| (__ia64_aar_i == -8) || (__ia64_aar_i == -16))) \
? ia64_fetch_and_add(__ia64_aar_i, &(v)->counter) \
: ia64_atomic64_add(__ia64_aar_i, v); \
})
/*
* Atomically add I to V and return TRUE if the resulting value is
* negative.
*/
static __inline__ int
atomic_add_negative (int i, atomic_t *v)
{
return atomic_add_return(i, v) < 0;
}
static __inline__ int
atomic64_add_negative (__s64 i, atomic64_t *v)
{
return atomic64_add_return(i, v) < 0;
}
#define atomic_sub_return(i,v) \
({ \
int __ia64_asr_i = (i); \
(__builtin_constant_p(i) \
&& ( (__ia64_asr_i == 1) || (__ia64_asr_i == 4) \
|| (__ia64_asr_i == 8) || (__ia64_asr_i == 16) \
|| (__ia64_asr_i == -1) || (__ia64_asr_i == -4) \
|| (__ia64_asr_i == -8) || (__ia64_asr_i == -16))) \
? ia64_fetch_and_add(-__ia64_asr_i, &(v)->counter) \
: ia64_atomic_sub(__ia64_asr_i, v); \
})
#define atomic64_sub_return(i,v) \
({ \
long __ia64_asr_i = (i); \
(__builtin_constant_p(i) \
&& ( (__ia64_asr_i == 1) || (__ia64_asr_i == 4) \
|| (__ia64_asr_i == 8) || (__ia64_asr_i == 16) \
|| (__ia64_asr_i == -1) || (__ia64_asr_i == -4) \
|| (__ia64_asr_i == -8) || (__ia64_asr_i == -16))) \
? ia64_fetch_and_add(-__ia64_asr_i, &(v)->counter) \
: ia64_atomic64_sub(__ia64_asr_i, v); \
})
#define atomic_dec_return(v) atomic_sub_return(1, (v))
#define atomic_inc_return(v) atomic_add_return(1, (v))
#define atomic64_dec_return(v) atomic64_sub_return(1, (v))
#define atomic64_inc_return(v) atomic64_add_return(1, (v))
#define atomic_sub_and_test(i,v) (atomic_sub_return((i), (v)) == 0)
#define atomic_dec_and_test(v) (atomic_sub_return(1, (v)) == 0)
#define atomic_inc_and_test(v) (atomic_add_return(1, (v)) == 0)
#define atomic64_sub_and_test(i,v) (atomic64_sub_return((i), (v)) == 0)
#define atomic64_dec_and_test(v) (atomic64_sub_return(1, (v)) == 0)
#define atomic64_inc_and_test(v) (atomic64_add_return(1, (v)) == 0)
#define atomic_add(i,v) atomic_add_return((i), (v))
#define atomic_sub(i,v) atomic_sub_return((i), (v))
#define atomic_inc(v) atomic_add(1, (v))
#define atomic_dec(v) atomic_sub(1, (v))
#define atomic64_add(i,v) atomic64_add_return((i), (v))
#define atomic64_sub(i,v) atomic64_sub_return((i), (v))
#define atomic64_inc(v) atomic64_add(1, (v))
#define atomic64_dec(v) atomic64_sub(1, (v))
/* 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()
#include <asm-generic/atomic.h>
#endif /* _ASM_IA64_ATOMIC_H */