diff options
Diffstat (limited to 'arch/alpha/include/asm/atomic.h')
| -rw-r--r-- | arch/alpha/include/asm/atomic.h | 165 |
1 files changed, 68 insertions, 97 deletions
diff --git a/arch/alpha/include/asm/atomic.h b/arch/alpha/include/asm/atomic.h index f62251e82ff..ed60a1ee1ed 100644 --- a/arch/alpha/include/asm/atomic.h +++ b/arch/alpha/include/asm/atomic.h @@ -3,6 +3,7 @@ #include <linux/types.h> #include <asm/barrier.h> +#include <asm/cmpxchg.h> /* * Atomic operations that C can't guarantee us. Useful for @@ -13,8 +14,8 @@ */ -#define ATOMIC_INIT(i) ( (atomic_t) { (i) } ) -#define ATOMIC64_INIT(i) ( (atomic64_t) { (i) } ) +#define ATOMIC_INIT(i) { (i) } +#define ATOMIC64_INIT(i) { (i) } #define atomic_read(v) (*(volatile int *)&(v)->counter) #define atomic64_read(v) (*(volatile long *)&(v)->counter) @@ -168,73 +169,6 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t * v) return result; } -/* - * Atomic exchange routines. - */ - -#define __ASM__MB -#define ____xchg(type, args...) __xchg ## type ## _local(args) -#define ____cmpxchg(type, args...) __cmpxchg ## type ## _local(args) -#include <asm/xchg.h> - -#define xchg_local(ptr,x) \ - ({ \ - __typeof__(*(ptr)) _x_ = (x); \ - (__typeof__(*(ptr))) __xchg_local((ptr), (unsigned long)_x_, \ - sizeof(*(ptr))); \ - }) - -#define cmpxchg_local(ptr, o, n) \ - ({ \ - __typeof__(*(ptr)) _o_ = (o); \ - __typeof__(*(ptr)) _n_ = (n); \ - (__typeof__(*(ptr))) __cmpxchg_local((ptr), (unsigned long)_o_, \ - (unsigned long)_n_, \ - sizeof(*(ptr))); \ - }) - -#define cmpxchg64_local(ptr, o, n) \ - ({ \ - BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ - cmpxchg_local((ptr), (o), (n)); \ - }) - -#ifdef CONFIG_SMP -#undef __ASM__MB -#define __ASM__MB "\tmb\n" -#endif -#undef ____xchg -#undef ____cmpxchg -#define ____xchg(type, args...) __xchg ##type(args) -#define ____cmpxchg(type, args...) __cmpxchg ##type(args) -#include <asm/xchg.h> - -#define xchg(ptr,x) \ - ({ \ - __typeof__(*(ptr)) _x_ = (x); \ - (__typeof__(*(ptr))) __xchg((ptr), (unsigned long)_x_, \ - sizeof(*(ptr))); \ - }) - -#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 cmpxchg64(ptr, o, n) \ - ({ \ - BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ - cmpxchg((ptr), (o), (n)); \ - }) - -#undef __ASM__MB -#undef ____cmpxchg - -#define __HAVE_ARCH_CMPXCHG 1 - #define atomic64_cmpxchg(v, old, new) (cmpxchg(&((v)->counter), old, new)) #define atomic64_xchg(v, new) (xchg(&((v)->counter), new)) @@ -252,17 +186,24 @@ static __inline__ long atomic64_sub_return(long i, atomic64_t * v) */ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int 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; - } - return c; + int c, new, old; + smp_mb(); + __asm__ __volatile__( + "1: ldl_l %[old],%[mem]\n" + " cmpeq %[old],%[u],%[c]\n" + " addl %[old],%[a],%[new]\n" + " bne %[c],2f\n" + " stl_c %[new],%[mem]\n" + " beq %[new],3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : [old] "=&r"(old), [new] "=&r"(new), [c] "=&r"(c) + : [mem] "m"(*v), [a] "rI"(a), [u] "rI"((long)u) + : "memory"); + smp_mb(); + return old; } @@ -273,21 +214,56 @@ static __inline__ int __atomic_add_unless(atomic_t *v, int a, int u) * @u: ...unless v is equal to u. * * Atomically adds @a to @v, so long as it was not @u. - * Returns the old value of @v. + * Returns true iff @v was not @u. */ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) { - long c, old; - c = atomic64_read(v); - for (;;) { - if (unlikely(c == (u))) - break; - old = atomic64_cmpxchg((v), c, c + (a)); - if (likely(old == c)) - break; - c = old; - } - return c != (u); + long c, tmp; + smp_mb(); + __asm__ __volatile__( + "1: ldq_l %[tmp],%[mem]\n" + " cmpeq %[tmp],%[u],%[c]\n" + " addq %[tmp],%[a],%[tmp]\n" + " bne %[c],2f\n" + " stq_c %[tmp],%[mem]\n" + " beq %[tmp],3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : [tmp] "=&r"(tmp), [c] "=&r"(c) + : [mem] "m"(*v), [a] "rI"(a), [u] "rI"(u) + : "memory"); + smp_mb(); + return !c; +} + +/* + * atomic64_dec_if_positive - decrement by 1 if old value positive + * @v: pointer of type atomic_t + * + * The function returns the old value of *v minus 1, even if + * the atomic variable, v, was not decremented. + */ +static inline long atomic64_dec_if_positive(atomic64_t *v) +{ + long old, tmp; + smp_mb(); + __asm__ __volatile__( + "1: ldq_l %[old],%[mem]\n" + " subq %[old],1,%[tmp]\n" + " ble %[old],2f\n" + " stq_c %[tmp],%[mem]\n" + " beq %[tmp],3f\n" + "2:\n" + ".subsection 2\n" + "3: br 1b\n" + ".previous" + : [old] "=&r"(old), [tmp] "=&r"(tmp) + : [mem] "m"(*v) + : "memory"); + smp_mb(); + return old - 1; } #define atomic64_inc_not_zero(v) atomic64_add_unless((v), 1, 0) @@ -316,9 +292,4 @@ static __inline__ int atomic64_add_unless(atomic64_t *v, long a, long u) #define atomic_dec(v) atomic_sub(1,(v)) #define atomic64_dec(v) atomic64_sub(1,(v)) -#define smp_mb__before_atomic_dec() smp_mb() -#define smp_mb__after_atomic_dec() smp_mb() -#define smp_mb__before_atomic_inc() smp_mb() -#define smp_mb__after_atomic_inc() smp_mb() - #endif /* _ALPHA_ATOMIC_H */ |