diff options
| -rw-r--r-- | arch/sparc/lib/atomic32.c | 15 | ||||
| -rw-r--r-- | include/asm-sparc/atomic.h | 38 |
2 files changed, 53 insertions, 0 deletions
diff --git a/arch/sparc/lib/atomic32.c b/arch/sparc/lib/atomic32.c index 559335f4917..617d29832e1 100644 --- a/arch/sparc/lib/atomic32.c +++ b/arch/sparc/lib/atomic32.c @@ -2,6 +2,7 @@ * atomic32.c: 32-bit atomic_t implementation * * Copyright (C) 2004 Keith M Wesolowski + * Copyright (C) 2007 Kyle McMartin * * Based on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf */ @@ -117,3 +118,17 @@ unsigned long ___change_bit(unsigned long *addr, unsigned long mask) return old & mask; } EXPORT_SYMBOL(___change_bit); + +unsigned long __cmpxchg_u32(volatile u32 *ptr, u32 old, u32 new) +{ + unsigned long flags; + u32 prev; + + spin_lock_irqsave(ATOMIC_HASH(addr), flags); + if ((prev = *ptr) == old) + *ptr = new; + spin_unlock_irqrestore(ATOMIC_HASH(addr), flags); + + return (unsigned long)prev; +} +EXPORT_SYMBOL(__cmpxchg_u32); diff --git a/include/asm-sparc/atomic.h b/include/asm-sparc/atomic.h index 731fa56e0c3..bdca5416d8b 100644 --- a/include/asm-sparc/atomic.h +++ b/include/asm-sparc/atomic.h @@ -2,6 +2,7 @@ * * 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>. @@ -10,11 +11,48 @@ #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 *); |