1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 32-bit atomic xchg() and cmpxchg() definitions. 3 * 4 * Copyright (C) 1996 David S. Miller (davem@davemloft.net) 5 * Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au) 6 * Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org) 7 * 8 * Additions by Keith M Wesolowski (wesolows@foobazco.org) based 9 * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>. 10 */ 11 12 #ifndef __ARCH_SPARC_CMPXCHG__ 13 #define __ARCH_SPARC_CMPXCHG__ 14 15 unsigned long __xchg_u32(volatile u32 *m, u32 new); 16 void __xchg_called_with_bad_pointer(void); 17 18 static inline unsigned long __xchg(unsigned long x, __volatile__ void * ptr, int size) 19 { 20 switch (size) { 21 case 4: 22 return __xchg_u32(ptr, x); 23 } 24 __xchg_called_with_bad_pointer(); 25 return x; 26 } 27 28 #define xchg(ptr,x) ((__typeof__(*(ptr)))__xchg((unsigned long)(x),(ptr),sizeof(*(ptr)))) 29 30 /* Emulate cmpxchg() the same way we emulate atomics, 31 * by hashing the object address and indexing into an array 32 * of spinlocks to get a bit of performance... 33 * 34 * See arch/sparc/lib/atomic32.c for implementation. 35 * 36 * Cribbed from <asm-parisc/atomic.h> 37 */ 38 39 /* bug catcher for when unsupported size is used - won't link */ 40 void __cmpxchg_called_with_bad_pointer(void); 41 /* we only need to support cmpxchg of a u32 on sparc */ 42 unsigned long __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_); 43 44 /* don't worry...optimizer will get rid of most of this */ 45 static inline unsigned long 46 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) 47 { 48 switch (size) { 49 case 4: 50 return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_); 51 default: 52 __cmpxchg_called_with_bad_pointer(); 53 break; 54 } 55 return old; 56 } 57 58 #define cmpxchg(ptr, o, n) \ 59 ({ \ 60 __typeof__(*(ptr)) _o_ = (o); \ 61 __typeof__(*(ptr)) _n_ = (n); \ 62 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ 63 (unsigned long)_n_, sizeof(*(ptr))); \ 64 }) 65 66 u64 __cmpxchg_u64(u64 *ptr, u64 old, u64 new); 67 #define cmpxchg64(ptr, old, new) __cmpxchg_u64(ptr, old, new) 68 69 #include <asm-generic/cmpxchg-local.h> 70 71 /* 72 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make 73 * them available. 74 */ 75 #define cmpxchg_local(ptr, o, n) \ 76 ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ 77 (unsigned long)(n), sizeof(*(ptr)))) 78 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 79 80 #endif /* __ARCH_SPARC_CMPXCHG__ */ 81