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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 | /* * Generic UP xchg and cmpxchg using interrupt disablement. Does not * support SMP. */ #ifndef __ASM_GENERIC_CMPXCHG_H #define __ASM_GENERIC_CMPXCHG_H #ifdef CONFIG_SMP #error "Cannot use generic cmpxchg on SMP" #endif #include <linux/types.h> #include <linux/irqflags.h> #ifndef xchg /* * This function doesn't exist, so you'll get a linker error if * something tries to do an invalidly-sized xchg(). */ extern void __xchg_called_with_bad_pointer(void); static inline unsigned long __xchg(unsigned long x, volatile void *ptr, int size) { unsigned long ret, flags; switch (size) { case 1: #ifdef __xchg_u8 return __xchg_u8(x, ptr); #else local_irq_save(flags); ret = *(volatile u8 *)ptr; *(volatile u8 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u8 */ case 2: #ifdef __xchg_u16 return __xchg_u16(x, ptr); #else local_irq_save(flags); ret = *(volatile u16 *)ptr; *(volatile u16 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u16 */ case 4: #ifdef __xchg_u32 return __xchg_u32(x, ptr); #else local_irq_save(flags); ret = *(volatile u32 *)ptr; *(volatile u32 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u32 */ #ifdef CONFIG_64BIT case 8: #ifdef __xchg_u64 return __xchg_u64(x, ptr); #else local_irq_save(flags); ret = *(volatile u64 *)ptr; *(volatile u64 *)ptr = x; local_irq_restore(flags); return ret; #endif /* __xchg_u64 */ #endif /* CONFIG_64BIT */ default: __xchg_called_with_bad_pointer(); return x; } } #define xchg(ptr, x) \ ((__typeof__(*(ptr))) __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))) #endif /* xchg */ /* * Atomic compare and exchange. * * Do not define __HAVE_ARCH_CMPXCHG because we want to use it to check whether * a cmpxchg primitive faster than repeated local irq save/restore exists. */ #include <asm-generic/cmpxchg-local.h> #ifndef cmpxchg_local #define cmpxchg_local(ptr, o, n) \ ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ (unsigned long)(n), sizeof(*(ptr)))) #endif #ifndef cmpxchg64_local #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) #endif #define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) #define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) #endif /* __ASM_GENERIC_CMPXCHG_H */ |