74 lines
1.5 KiB
C
74 lines
1.5 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _TOOLS_LINUX_ASM_X86_ATOMIC_H
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#define _TOOLS_LINUX_ASM_X86_ATOMIC_H
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#include <linux/compiler.h>
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#include <linux/types.h>
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#include "rmwcc.h"
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#define LOCK_PREFIX "\n\tlock; "
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#include <asm/cmpxchg.h>
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/*
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* Atomic operations that C can't guarantee us. Useful for
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* resource counting etc..
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*/
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#define ATOMIC_INIT(i) { (i) }
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/**
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* atomic_read - read atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically reads the value of @v.
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*/
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static inline int atomic_read(const atomic_t *v)
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{
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return READ_ONCE((v)->counter);
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}
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/**
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* atomic_set - set atomic variable
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* @v: pointer of type atomic_t
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* @i: required value
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*
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* Atomically sets the value of @v to @i.
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*/
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static inline void atomic_set(atomic_t *v, int i)
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{
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v->counter = i;
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}
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/**
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* atomic_inc - increment atomic variable
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* @v: pointer of type atomic_t
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*
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* Atomically increments @v by 1.
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*/
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static inline void atomic_inc(atomic_t *v)
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{
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asm volatile(LOCK_PREFIX "incl %0"
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: "+m" (v->counter));
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}
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/**
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* atomic_dec_and_test - decrement and test
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* @v: pointer of type atomic_t
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*
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* Atomically decrements @v by 1 and
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* returns true if the result is 0, or false for all other
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* cases.
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*/
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static inline int atomic_dec_and_test(atomic_t *v)
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{
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GEN_UNARY_RMWcc(LOCK_PREFIX "decl", v->counter, "%0", "e");
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}
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static __always_inline int atomic_cmpxchg(atomic_t *v, int old, int new)
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{
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return cmpxchg(&v->counter, old, new);
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}
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#endif /* _TOOLS_LINUX_ASM_X86_ATOMIC_H */
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