projects / linux-2.6-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b2441318 | 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| b4816afa DH |
2 | /* |
| 3 | * Generic UP xchg and cmpxchg using interrupt disablement. Does not | |
| 4 | * support SMP. | |
| 5 | */ | |
| 6 | ||
| 068fbad2 MD |
7 | #ifndef __ASM_GENERIC_CMPXCHG_H |
| 8 | #define __ASM_GENERIC_CMPXCHG_H | |
| 9 | ||
| 068fbad2 MD |
10 | #ifdef CONFIG_SMP |
| 11 | #error "Cannot use generic cmpxchg on SMP" | |
| 12 | #endif | |
| 13 | ||
| 80da6a4f | 14 | #include <linux/types.h> |
| b4816afa DH |
15 | #include <linux/irqflags.h> |
| 16 | ||
| b4816afa DH |
17 | /* |
| 18 | * This function doesn't exist, so you'll get a linker error if | |
| 19 | * something tries to do an invalidly-sized xchg(). | |
| 20 | */ | |
| 82b993e8 | 21 | extern void __generic_xchg_called_with_bad_pointer(void); |
| b4816afa DH |
22 | |
| 23 | static inline | |
| 82b993e8 | 24 | unsigned long __generic_xchg(unsigned long x, volatile void *ptr, int size) |
| b4816afa DH |
25 | { |
| 26 | unsigned long ret, flags; | |
| 27 | ||
| 28 | switch (size) { | |
| 29 | case 1: | |
| 30 | #ifdef __xchg_u8 | |
| 31 | return __xchg_u8(x, ptr); | |
| 32 | #else | |
| 33 | local_irq_save(flags); | |
| 34 | ret = *(volatile u8 *)ptr; | |
| 656e9007 | 35 | *(volatile u8 *)ptr = (x & 0xffu); |
| b4816afa DH |
36 | local_irq_restore(flags); |
| 37 | return ret; | |
| 38 | #endif /* __xchg_u8 */ | |
| 39 | ||
| 40 | case 2: | |
| 41 | #ifdef __xchg_u16 | |
| 42 | return __xchg_u16(x, ptr); | |
| 43 | #else | |
| 44 | local_irq_save(flags); | |
| 45 | ret = *(volatile u16 *)ptr; | |
| 656e9007 | 46 | *(volatile u16 *)ptr = (x & 0xffffu); |
| b4816afa DH |
47 | local_irq_restore(flags); |
| 48 | return ret; | |
| 49 | #endif /* __xchg_u16 */ | |
| 50 | ||
| 51 | case 4: | |
| 52 | #ifdef __xchg_u32 | |
| 53 | return __xchg_u32(x, ptr); | |
| 54 | #else | |
| 55 | local_irq_save(flags); | |
| 56 | ret = *(volatile u32 *)ptr; | |
| 656e9007 | 57 | *(volatile u32 *)ptr = (x & 0xffffffffu); |
| b4816afa DH |
58 | local_irq_restore(flags); |
| 59 | return ret; | |
| 60 | #endif /* __xchg_u32 */ | |
| 61 | ||
| 62 | #ifdef CONFIG_64BIT | |
| 63 | case 8: | |
| 64 | #ifdef __xchg_u64 | |
| 65 | return __xchg_u64(x, ptr); | |
| 66 | #else | |
| 67 | local_irq_save(flags); | |
| 68 | ret = *(volatile u64 *)ptr; | |
| 69 | *(volatile u64 *)ptr = x; | |
| 70 | local_irq_restore(flags); | |
| 71 | return ret; | |
| 72 | #endif /* __xchg_u64 */ | |
| 73 | #endif /* CONFIG_64BIT */ | |
| 74 | ||
| 75 | default: | |
| 82b993e8 | 76 | __generic_xchg_called_with_bad_pointer(); |
| b4816afa DH |
77 | return x; |
| 78 | } | |
| 79 | } | |
| 80 | ||
| 82b993e8 MR |
81 | #define generic_xchg(ptr, x) ({ \ |
| 82 | ((__typeof__(*(ptr))) \ | |
| 83 | __generic_xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ | |
| d975440b | 84 | }) |
| b4816afa | 85 | |
| 068fbad2 MD |
86 | /* |
| 87 | * Atomic compare and exchange. | |
| 068fbad2 | 88 | */ |
| b4816afa DH |
89 | #include <asm-generic/cmpxchg-local.h> |
| 90 | ||
| 82b993e8 MR |
91 | #define generic_cmpxchg_local(ptr, o, n) ({ \ |
| 92 | ((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o), \ | |
| 93 | (unsigned long)(n), sizeof(*(ptr)))); \ | |
| d975440b | 94 | }) |
| 82b993e8 MR |
95 | |
| 96 | #define generic_cmpxchg64_local(ptr, o, n) \ | |
| 97 | __generic_cmpxchg64_local((ptr), (o), (n)) | |
| 98 | ||
| 99 | ||
| 82b993e8 MR |
100 | #ifndef arch_xchg |
| 101 | #define arch_xchg generic_xchg | |
| 102 | #endif | |
| 103 | ||
| 104 | #ifndef arch_cmpxchg_local | |
| 105 | #define arch_cmpxchg_local generic_cmpxchg_local | |
| 106 | #endif | |
| 107 | ||
| 108 | #ifndef arch_cmpxchg64_local | |
| 109 | #define arch_cmpxchg64_local generic_cmpxchg64_local | |
| 110 | #endif | |
| 111 | ||
| 112 | #define arch_cmpxchg arch_cmpxchg_local | |
| 113 | #define arch_cmpxchg64 arch_cmpxchg64_local | |
| 114 | ||
| b4816afa | 115 | #endif /* __ASM_GENERIC_CMPXCHG_H */ |