1 /* 32-bit atomic xchg() and cmpxchg() definitions. 2 * 3 * Copyright (C) 1996 David S. Miller (davem@davemloft.net) 4 * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au) 5 * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org) 6 * 7 * Additions by Keith M Wesolowski (wesolows@foobazco.org) based 8 * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>. 9 */ 10 11 #ifndef __ARCH_SPARC_CMPXCHG__ 12 #define __ARCH_SPARC_CMPXCHG__ 13 14 unsigned long __xchg_u32(volatile u32 *m, u32 new); 15 void __xchg_called_with_bad_pointer(void); 16 17 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int size) 18 { 19 switch (size) { 20 case 4: 21 return __xchg_u32(ptr, x); 22 } 23 __xchg_called_with_bad_pointer(); 24 return x; 25 } 26 27 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) 28 29 /* Emulate cmpxchg() the same way we emulate atomics, 30 * by hashing the object address and indexing into an array 31 * of spinlocks to get a bit of performance... 32 * 33 * See arch/sparc/lib/atomic32.c for implementation. 34 * 35 * Cribbed from <asm-parisc/atomic.h> 36 */ 37 38 /* bug catcher for when unsupported size is used - won't link */ 39 void __cmpxchg_called_with_bad_pointer(void); 40 /* we only need to support cmpxchg of a u32 on sparc */ 41 unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_); 42 43 /* don't worry...optimizer will get rid of most of this */ 44 static inline unsigned long 45 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) 46 { 47 switch (size) { 48 case 4: 49 return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_); 50 default: 51 __cmpxchg_called_with_bad_pointer(); 52 break; 53 } 54 return old; 55 } 56 57 #define cmpxchg(ptr, o, n) \ 58 ({ \ 59 __typeof__(*(ptr)) _o_ = (o); \ 60 __typeof__(*(ptr)) _n_ = (n); \ 61 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ 62 (unsigned long)_n_, sizeof(*(ptr))); \ 63 }) 64 65 #include <asm-generic/cmpxchg-local.h> 66 67 /* 68 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make 69 * them available. 70 */ 71 #define cmpxchg_local(ptr, o, n) \ 72 ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ 73 (unsigned long)(n), sizeof(*(ptr)))) 74 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 75 76 #endif /* __ARCH_SPARC_CMPXCHG__ */ 77