mirror of https://gitee.com/openkylin/linux.git
86 lines
2.5 KiB
C
86 lines
2.5 KiB
C
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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 (davem@davemloft.net)
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* Copyright (C) 2000 Anton Blanchard (anton@linuxcare.com.au)
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* Copyright (C) 2007 Kyle McMartin (kyle@parisc-linux.org)
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*
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* Additions by Keith M Wesolowski (wesolows@foobazco.org) based
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* on asm-parisc/atomic.h Copyright (C) 2000 Philipp Rumpf <prumpf@tux.org>.
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*/
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#ifndef __ARCH_SPARC_CMPXCHG__
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#define __ARCH_SPARC_CMPXCHG__
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static inline unsigned long xchg_u32(__volatile__ unsigned long *m, unsigned long val)
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{
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__asm__ __volatile__("swap [%2], %0"
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: "=&r" (val)
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: "0" (val), "r" (m)
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: "memory");
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return val;
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}
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extern void __xchg_called_with_bad_pointer(void);
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static inline unsigned long __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 xchg(ptr,x) ((__typeof__(*(ptr)))__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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#define __HAVE_ARCH_CMPXCHG 1
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/* bug catcher for when unsupported size is used - won't link */
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extern void __cmpxchg_called_with_bad_pointer(void);
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/* we only need to support cmpxchg of a u32 on sparc */
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extern unsigned long __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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switch (size) {
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case 4:
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return __cmpxchg_u32((u32 *)ptr, (u32)old, (u32)new_);
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default:
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__cmpxchg_called_with_bad_pointer();
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break;
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}
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return old;
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}
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#define 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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#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 cmpxchg_local(ptr, o, n) \
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((__typeof__(*(ptr)))__cmpxchg_local_generic((ptr), (unsigned long)(o),\
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(unsigned long)(n), sizeof(*(ptr))))
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#define cmpxchg64_local(ptr, o, n) __cmpxchg64_local_generic((ptr), (o), (n))
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#endif /* __ARCH_SPARC_CMPXCHG__ */
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