1 /* 2 * forked from parisc asm/atomic.h which was: 3 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> 4 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org> 5 */ 6 7 #ifndef _ASM_PARISC_CMPXCHG_H_ 8 #define _ASM_PARISC_CMPXCHG_H_ 9 10 /* This should get optimized out since it's never called. 11 ** Or get a link error if xchg is used "wrong". 12 */ 13 extern void __xchg_called_with_bad_pointer(void); 14 15 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */ 16 extern unsigned long __xchg8(char, char *); 17 extern unsigned long __xchg32(int, int *); 18 #ifdef CONFIG_64BIT 19 extern unsigned long __xchg64(unsigned long, unsigned long *); 20 #endif 21 22 /* optimizer better get rid of switch since size is a constant */ 23 static inline unsigned long 24 __xchg(unsigned long x, __volatile__ void *ptr, int size) 25 { 26 switch (size) { 27 #ifdef CONFIG_64BIT 28 case 8: return __xchg64(x, (unsigned long *) ptr); 29 #endif 30 case 4: return __xchg32((int) x, (int *) ptr); 31 case 1: return __xchg8((char) x, (char *) ptr); 32 } 33 __xchg_called_with_bad_pointer(); 34 return x; 35 } 36 37 /* 38 ** REVISIT - Abandoned use of LDCW in xchg() for now: 39 ** o need to test sizeof(*ptr) to avoid clearing adjacent bytes 40 ** o and while we are at it, could CONFIG_64BIT code use LDCD too? 41 ** 42 ** if (__builtin_constant_p(x) && (x == NULL)) 43 ** if (((unsigned long)p & 0xf) == 0) 44 ** return __ldcw(p); 45 */ 46 #define xchg(ptr, x) \ 47 ((__typeof__(*(ptr)))__xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))) 48 49 /* bug catcher for when unsupported size is used - won't link */ 50 extern void __cmpxchg_called_with_bad_pointer(void); 51 52 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */ 53 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, 54 unsigned int new_); 55 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_); 56 57 /* don't worry...optimizer will get rid of most of this */ 58 static inline unsigned long 59 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) 60 { 61 switch (size) { 62 #ifdef CONFIG_64BIT 63 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_); 64 #endif 65 case 4: return __cmpxchg_u32((unsigned int *)ptr, 66 (unsigned int)old, (unsigned int)new_); 67 } 68 __cmpxchg_called_with_bad_pointer(); 69 return old; 70 } 71 72 #define cmpxchg(ptr, o, n) \ 73 ({ \ 74 __typeof__(*(ptr)) _o_ = (o); \ 75 __typeof__(*(ptr)) _n_ = (n); \ 76 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ 77 (unsigned long)_n_, sizeof(*(ptr))); \ 78 }) 79 80 #include <asm-generic/cmpxchg-local.h> 81 82 static inline unsigned long __cmpxchg_local(volatile void *ptr, 83 unsigned long old, 84 unsigned long new_, int size) 85 { 86 switch (size) { 87 #ifdef CONFIG_64BIT 88 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_); 89 #endif 90 case 4: return __cmpxchg_u32(ptr, old, new_); 91 default: 92 return __cmpxchg_local_generic(ptr, old, new_, size); 93 } 94 } 95 96 /* 97 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make 98 * them available. 99 */ 100 #define cmpxchg_local(ptr, o, n) \ 101 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \ 102 (unsigned long)(n), sizeof(*(ptr)))) 103 #ifdef CONFIG_64BIT 104 #define cmpxchg64_local(ptr, o, n) \ 105 ({ \ 106 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 107 cmpxchg_local((ptr), (o), (n)); \ 108 }) 109 #else 110 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 111 #endif 112 113 #define cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n) 114 115 #endif /* _ASM_PARISC_CMPXCHG_H_ */ 116