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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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 | /* SPDX-License-Identifier: GPL-2.0 */ /* * 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> /* * This function doesn't exist, so you'll get a linker error if * something tries to do an invalidly-sized xchg(). */ extern void __generic_xchg_called_with_bad_pointer(void); static inline unsigned long __generic_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: __generic_xchg_called_with_bad_pointer(); return x; } } #define generic_xchg(ptr, x) ({ \ ((__typeof__(*(ptr))) \ __generic_xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ }) /* * Atomic compare and exchange. */ #include <asm-generic/cmpxchg-local.h> #define generic_cmpxchg_local(ptr, o, n) ({ \ ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o), \ (unsigned long)(n), sizeof(*(ptr)))); \ }) #define generic_cmpxchg64_local(ptr, o, n) \ __generic_cmpxchg64_local((ptr), (o), (n)) #ifndef arch_xchg #define arch_xchg generic_xchg #endif #ifndef arch_cmpxchg_local #define arch_cmpxchg_local generic_cmpxchg_local #endif #ifndef arch_cmpxchg64_local #define arch_cmpxchg64_local generic_cmpxchg64_local #endif #define arch_cmpxchg arch_cmpxchg_local #define arch_cmpxchg64 arch_cmpxchg64_local #endif /* __ASM_GENERIC_CMPXCHG_H */ |