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torvalds
GitHub Repository: torvalds/linux
 Path: blob/master/arch/sparc/include/asm/cmpxchg_32.h
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/* SPDX-License-Identifier: GPL-2.0 */

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/* 32-bit atomic xchg() and cmpxchg() definitions.

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 *

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 * Copyright (C) 1996 David S. Miller ([email protected])

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 * Copyright (C) 2000 Anton Blanchard ([email protected])

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 * Copyright (C) 2007 Kyle McMartin ([email protected])

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 *

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 * Additions by Keith M Wesolowski ([email protected]) based

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 * on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <[email protected]>.

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 */

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#ifndef __ARCH_SPARC_CMPXCHG__

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#define __ARCH_SPARC_CMPXCHG__

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unsigned long __xchg_u32(volatile u32 *m, u32 new);

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void __xchg_called_with_bad_pointer(void);

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static __always_inline unsigned long __arch_xchg(unsigned long x, __volatile__ void * ptr, int size)

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{

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	switch (size) {

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	case 4:

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		return __xchg_u32(ptr, x);

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	}

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	__xchg_called_with_bad_pointer();

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	return x;

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}

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#define arch_xchg(ptr,x) ({(__typeof__(*(ptr)))__arch_xchg((unsigned long)(x),(ptr),sizeof(*(ptr)));})

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/* Emulate cmpxchg() the same way we emulate atomics,

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 * by hashing the object address and indexing into an array

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 * of spinlocks to get a bit of performance...

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 *

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 * See arch/sparc/lib/atomic32.c for implementation.

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 *

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 * Cribbed from <asm-parisc/atomic.h>

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 */

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/* bug catcher for when unsupported size is used - won't link */

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void __cmpxchg_called_with_bad_pointer(void);

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u8 __cmpxchg_u8(volatile u8 *m, u8 old, u8 new_);

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u16 __cmpxchg_u16(volatile u16 *m, u16 old, u16 new_);

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u32 __cmpxchg_u32(volatile u32 *m, u32 old, u32 new_);

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/* don't worry...optimizer will get rid of most of this */

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static inline unsigned long

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__cmpxchg(volatile void *ptr, unsigned long old, unsigned long new_, int size)

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{

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	return

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		size == 1 ? __cmpxchg_u8(ptr, old, new_) :

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		size == 2 ? __cmpxchg_u16(ptr, old, new_) :

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		size == 4 ? __cmpxchg_u32(ptr, old, new_) :

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			(__cmpxchg_called_with_bad_pointer(), old);

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}

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#define arch_cmpxchg(ptr, o, n)						\

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({									\

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	__typeof__(*(ptr)) _o_ = (o);					\

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	__typeof__(*(ptr)) _n_ = (n);					\

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	(__typeof__(*(ptr))) __cmpxchg((ptr), (unsigned long)_o_,	\

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			(unsigned long)_n_, sizeof(*(ptr)));		\

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})

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u64 __cmpxchg_u64(volatile u64 *ptr, u64 old, u64 new);

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#define arch_cmpxchg64(ptr, old, new)	__cmpxchg_u64(ptr, old, new)

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#include <asm-generic/cmpxchg-local.h>

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/*

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 * cmpxchg_local and cmpxchg64_local are atomic wrt current CPU. Always make

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 * them available.

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 */

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#define arch_cmpxchg_local(ptr, o, n)				  	       \

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	((__typeof__(*(ptr)))__generic_cmpxchg_local((ptr), (unsigned long)(o),\

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			(unsigned long)(n), sizeof(*(ptr))))

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#define arch_cmpxchg64_local(ptr, o, n) __generic_cmpxchg64_local((ptr), (o), (n))

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#endif /* __ARCH_SPARC_CMPXCHG__ */

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