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 #define __HAVE_ARCH_CMPXCHG 1 50 51 /* bug catcher for when unsupported size is used - won't link */ 52 extern void __cmpxchg_called_with_bad_pointer(void); 53 54 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */ 55 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, 56 unsigned int new_); 57 extern unsigned long __cmpxchg_u64(volatile unsigned long *ptr, 58 unsigned long old, unsigned long new_); 59 60 /* don't worry...optimizer will get rid of most of this */ 61 static inline unsigned long 62 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) 63 { 64 switch (size) { 65 #ifdef CONFIG_64BIT 66 case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_); 67 #endif 68 case 4: return __cmpxchg_u32((unsigned int *)ptr, 69 (unsigned int)old, (unsigned int)new_); 70 } 71 __cmpxchg_called_with_bad_pointer(); 72 return old; 73 } 74 75 #define cmpxchg(ptr, o, n) \ 76 ({ \ 77 __typeof__(*(ptr)) _o_ = (o); \ 78 __typeof__(*(ptr)) _n_ = (n); \ 79 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ 80 (unsigned long)_n_, sizeof(*(ptr))); \ 81 }) 82 83 #include <asm-generic/cmpxchg-local.h> 84 85 static inline unsigned long __cmpxchg_local(volatile void *ptr, 86 unsigned long old, 87 unsigned long new_, int size) 88 { 89 switch (size) { 90 #ifdef CONFIG_64BIT 91 case 8: return __cmpxchg_u64((unsigned long *)ptr, old, new_); 92 #endif 93 case 4: return __cmpxchg_u32(ptr, old, new_); 94 default: 95 return __cmpxchg_local_generic(ptr, old, new_, size); 96 } 97 } 98 99 /* 100 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make 101 * them available. 102 */ 103 #define cmpxchg_local(ptr, o, n) \ 104 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \ 105 (unsigned long)(n), sizeof(*(ptr)))) 106 #ifdef CONFIG_64BIT 107 #define cmpxchg64_local(ptr, o, n) \ 108 ({ \ 109 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 110 cmpxchg_local((ptr), (o), (n)); \ 111 }) 112 #else 113 #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) 114 #endif 115 116 #endif /* _ASM_PARISC_CMPXCHG_H_ */ 117