| Kyle Swenson | 8d8f654 | 2021-03-15 11:02:55 -0600 | [diff] [blame^] | 1 | /* |
| 2 | * Generic UP xchg and cmpxchg using interrupt disablement. Does not |
| 3 | * support SMP. |
| 4 | */ |
| 5 | |
| 6 | #ifndef __ASM_GENERIC_CMPXCHG_H |
| 7 | #define __ASM_GENERIC_CMPXCHG_H |
| 8 | |
| 9 | #ifdef CONFIG_SMP |
| 10 | #error "Cannot use generic cmpxchg on SMP" |
| 11 | #endif |
| 12 | |
| 13 | #include <linux/types.h> |
| 14 | #include <linux/irqflags.h> |
| 15 | |
| 16 | #ifndef xchg |
| 17 | |
| 18 | /* |
| 19 | * This function doesn't exist, so you'll get a linker error if |
| 20 | * something tries to do an invalidly-sized xchg(). |
| 21 | */ |
| 22 | extern void __xchg_called_with_bad_pointer(void); |
| 23 | |
| 24 | static inline |
| 25 | unsigned long __xchg(unsigned long x, volatile void *ptr, int size) |
| 26 | { |
| 27 | unsigned long ret, flags; |
| 28 | |
| 29 | switch (size) { |
| 30 | case 1: |
| 31 | #ifdef __xchg_u8 |
| 32 | return __xchg_u8(x, ptr); |
| 33 | #else |
| 34 | local_irq_save(flags); |
| 35 | ret = *(volatile u8 *)ptr; |
| 36 | *(volatile u8 *)ptr = x; |
| 37 | local_irq_restore(flags); |
| 38 | return ret; |
| 39 | #endif /* __xchg_u8 */ |
| 40 | |
| 41 | case 2: |
| 42 | #ifdef __xchg_u16 |
| 43 | return __xchg_u16(x, ptr); |
| 44 | #else |
| 45 | local_irq_save(flags); |
| 46 | ret = *(volatile u16 *)ptr; |
| 47 | *(volatile u16 *)ptr = x; |
| 48 | local_irq_restore(flags); |
| 49 | return ret; |
| 50 | #endif /* __xchg_u16 */ |
| 51 | |
| 52 | case 4: |
| 53 | #ifdef __xchg_u32 |
| 54 | return __xchg_u32(x, ptr); |
| 55 | #else |
| 56 | local_irq_save(flags); |
| 57 | ret = *(volatile u32 *)ptr; |
| 58 | *(volatile u32 *)ptr = x; |
| 59 | local_irq_restore(flags); |
| 60 | return ret; |
| 61 | #endif /* __xchg_u32 */ |
| 62 | |
| 63 | #ifdef CONFIG_64BIT |
| 64 | case 8: |
| 65 | #ifdef __xchg_u64 |
| 66 | return __xchg_u64(x, ptr); |
| 67 | #else |
| 68 | local_irq_save(flags); |
| 69 | ret = *(volatile u64 *)ptr; |
| 70 | *(volatile u64 *)ptr = x; |
| 71 | local_irq_restore(flags); |
| 72 | return ret; |
| 73 | #endif /* __xchg_u64 */ |
| 74 | #endif /* CONFIG_64BIT */ |
| 75 | |
| 76 | default: |
| 77 | __xchg_called_with_bad_pointer(); |
| 78 | return x; |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | #define xchg(ptr, x) ({ \ |
| 83 | ((__typeof__(*(ptr))) \ |
| 84 | __xchg((unsigned long)(x), (ptr), sizeof(*(ptr)))); \ |
| 85 | }) |
| 86 | |
| 87 | #endif /* xchg */ |
| 88 | |
| 89 | /* |
| 90 | * Atomic compare and exchange. |
| 91 | */ |
| 92 | #include <asm-generic/cmpxchg-local.h> |
| 93 | |
| 94 | #ifndef cmpxchg_local |
| 95 | #define cmpxchg_local(ptr, o, n) ({ \ |
| 96 | ((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\ |
| 97 | (unsigned long)(n), sizeof(*(ptr)))); \ |
| 98 | }) |
| 99 | #endif |
| 100 | |
| 101 | #ifndef cmpxchg64_local |
| 102 | #define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n)) |
| 103 | #endif |
| 104 | |
| 105 | #define cmpxchg(ptr, o, n) cmpxchg_local((ptr), (o), (n)) |
| 106 | #define cmpxchg64(ptr, o, n) cmpxchg64_local((ptr), (o), (n)) |
| 107 | |
| 108 | #endif /* __ASM_GENERIC_CMPXCHG_H */ |