1 /* SPDX-License-Identifier: GPL-2.0 */ 2 /* 3 * forked from parisc asm/atomic.h which was: 4 * Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org> 5 * Copyright (C) 2006 Kyle McMartin <kyle@parisc-linux.org> 6 */ 7 8 #ifndef _ASM_PARISC_CMPXCHG_H_ 9 #define _ASM_PARISC_CMPXCHG_H_ 10 11 /* This should get optimized out since it's never called. 12 ** Or get a link error if xchg is used "wrong". 13 */ 14 extern void __xchg_called_with_bad_pointer(void); 15 16 /* __xchg32/64 defined in arch/parisc/lib/bitops.c */ 17 extern unsigned long __xchg8(char, volatile char *); 18 extern unsigned long __xchg32(int, volatile int *); 19 #ifdef CONFIG_64BIT 20 extern unsigned long __xchg64(unsigned long, volatile unsigned long *); 21 #endif 22 23 /* optimizer better get rid of switch since size is a constant */ 24 static inline unsigned long 25 __arch_xchg(unsigned long x, volatile void *ptr, int size) 26 { 27 switch (size) { 28 #ifdef CONFIG_64BIT 29 case 8: return __xchg64(x, (volatile unsigned long *) ptr); 30 #endif 31 case 4: return __xchg32((int) x, (volatile int *) ptr); 32 case 1: return __xchg8((char) x, (volatile char *) ptr); 33 } 34 __xchg_called_with_bad_pointer(); 35 return x; 36 } 37 38 /* 39 ** REVISIT - Abandoned use of LDCW in xchg() for now: 40 ** o need to test sizeof(*ptr) to avoid clearing adjacent bytes 41 ** o and while we are at it, could CONFIG_64BIT code use LDCD too? 42 ** 43 ** if (__builtin_constant_p(x) && (x == NULL)) 44 ** if (((unsigned long)p & 0xf) == 0) 45 ** return __ldcw(p); 46 */ 47 #define arch_xchg(ptr, x) \ 48 ({ \ 49 __typeof__(*(ptr)) __ret; \ 50 __typeof__(*(ptr)) _x_ = (x); \ 51 __ret = (__typeof__(*(ptr))) \ 52 __arch_xchg((unsigned long)_x_, (ptr), sizeof(*(ptr))); \ 53 __ret; \ 54 }) 55 56 /* bug catcher for when unsupported size is used - won't link */ 57 extern void __cmpxchg_called_with_bad_pointer(void); 58 59 /* __cmpxchg_u32/u64 defined in arch/parisc/lib/bitops.c */ 60 extern unsigned long __cmpxchg_u32(volatile unsigned int *m, unsigned int old, 61 unsigned int new_); 62 extern u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new_); 63 extern u8 __cmpxchg_u8(volatile u8 *ptr, u8 old, u8 new_); 64 65 /* don't worry...optimizer will get rid of most of this */ 66 static inline unsigned long 67 __cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size) 68 { 69 switch (size) { 70 #ifdef CONFIG_64BIT 71 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_); 72 #endif 73 case 4: return __cmpxchg_u32((unsigned int *)ptr, 74 (unsigned int)old, (unsigned int)new_); 75 case 1: return __cmpxchg_u8((u8 *)ptr, old & 0xff, new_ & 0xff); 76 } 77 __cmpxchg_called_with_bad_pointer(); 78 return old; 79 } 80 81 #define arch_cmpxchg(ptr, o, n) \ 82 ({ \ 83 __typeof__(*(ptr)) _o_ = (o); \ 84 __typeof__(*(ptr)) _n_ = (n); \ 85 (__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_, \ 86 (unsigned long)_n_, sizeof(*(ptr))); \ 87 }) 88 89 #include <asm-generic/cmpxchg-local.h> 90 91 static inline unsigned long __cmpxchg_local(volatile void *ptr, 92 unsigned long old, 93 unsigned long new_, int size) 94 { 95 switch (size) { 96 #ifdef CONFIG_64BIT 97 case 8: return __cmpxchg_u64((u64 *)ptr, old, new_); 98 #endif 99 case 4: return __cmpxchg_u32(ptr, old, new_); 100 default: 101 return __generic_cmpxchg_local(ptr, old, new_, size); 102 } 103 } 104 105 /* 106 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make 107 * them available. 108 */ 109 #define arch_cmpxchg_local(ptr, o, n) \ 110 ((__typeof__(*(ptr)))__cmpxchg_local((ptr), (unsigned long)(o), \ 111 (unsigned long)(n), sizeof(*(ptr)))) 112 #ifdef CONFIG_64BIT 113 #define arch_cmpxchg64_local(ptr, o, n) \ 114 ({ \ 115 BUILD_BUG_ON(sizeof(*(ptr)) != 8); \ 116 cmpxchg_local((ptr), (o), (n)); \ 117 }) 118 #else 119 #define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n)) 120 #endif 121 122 #define arch_cmpxchg64(ptr, o, n) __cmpxchg_u64(ptr, o, n) 123 124 #endif /* _ASM_PARISC_CMPXCHG_H_ */ 125