| 1 |
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| 2 | #ifndef __ASM_GENERIC_CMPXCHG_LOCAL_H
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| 3 | #define __ASM_GENERIC_CMPXCHG_LOCAL_H
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| 4 |
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| 5 | #include <linux/types.h>
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| 6 | #include <linux/irqflags.h>
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| 7 |
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| 8 | extern unsigned long wrong_size_cmpxchg(volatile void *ptr)
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| 9 | __noreturn;
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| 10 |
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| 11 | |
| 12 | * Generic version of __cmpxchg_local (disables interrupts). Takes an unsigned
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| 13 | * long parameter, supporting various types of architectures.
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| 14 |
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| 15 | static inline unsigned long __generic_cmpxchg_local(volatile void *ptr,
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| 16 | unsigned long old, unsigned long new, int size)
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| 17 | {
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| 18 | unsigned long flags, prev;
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| 19 |
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| 20 | |
| 21 | * Sanity checking, compile-time.
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| 22 |
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| 23 | if (size == 8 && sizeof(unsigned long) != 8)
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| 24 | wrong_size_cmpxchg(ptr);
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| 25 |
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| 26 | raw_local_irq_save(flags);
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| 27 | switch (size) {
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| 28 | case 1: prev = *(u8 *)ptr;
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| 29 | if (prev == (old & 0xffu))
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| 30 | *(u8 *)ptr = (new & 0xffu);
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| 31 | break;
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| 32 | case 2: prev = *(u16 *)ptr;
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| 33 | if (prev == (old & 0xffffu))
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| 34 | *(u16 *)ptr = (new & 0xffffu);
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| 35 | break;
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| 36 | case 4: prev = *(u32 *)ptr;
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| 37 | if (prev == (old & 0xffffffffu))
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| 38 | *(u32 *)ptr = (new & 0xffffffffu);
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| 39 | break;
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| 40 | case 8: prev = *(u64 *)ptr;
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| 41 | if (prev == old)
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| 42 | *(u64 *)ptr = (u64)new;
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| 43 | break;
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| 44 | default:
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| 45 | wrong_size_cmpxchg(ptr);
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| 46 | }
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| 47 | raw_local_irq_restore(flags);
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| 48 | return prev;
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| 49 | }
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| 50 |
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| 51 | |
| 52 | * Generic version of __cmpxchg64_local. Takes an u64 parameter.
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| 53 |
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| 54 | static inline u64 __generic_cmpxchg64_local(volatile void *ptr,
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| 55 | u64 old, u64 new)
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| 56 | {
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| 57 | u64 prev;
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| 58 | unsigned long flags;
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| 59 |
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| 60 | raw_local_irq_save(flags);
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| 61 | prev = *(u64 *)ptr;
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| 62 | if (prev == old)
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| 63 | *(u64 *)ptr = new;
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| 64 | raw_local_irq_restore(flags);
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| 65 | return prev;
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| 66 | }
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| 67 |
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| 68 | #endif
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