65 lines
1 KiB
C
65 lines
1 KiB
C
// SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
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/* Copyright 2017 IBM Corp. */
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#ifndef __CMPXCHG_H
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#define __CMPXCHG_H
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#ifndef __TEST__
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/*
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* Bare cmpxchg, no barriers.
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*/
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static inline uint32_t __cmpxchg32(uint32_t *mem, uint32_t old, uint32_t new)
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{
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uint32_t prev;
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asm volatile(
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"# __cmpxchg32 \n"
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"1: lwarx %0,0,%2 \n"
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" cmpw %0,%3 \n"
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" bne- 2f \n"
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" stwcx. %4,0,%2 \n"
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" bne- 1b \n"
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"2: \n"
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: "=&r"(prev), "+m"(*mem)
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: "r"(mem), "r"(old), "r"(new)
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: "cr0");
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return prev;
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}
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static inline uint64_t __cmpxchg64(uint64_t *mem, uint64_t old, uint64_t new)
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{
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uint64_t prev;
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asm volatile(
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"# __cmpxchg64 \n"
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"1: ldarx %0,0,%2 \n"
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" cmpd %0,%3 \n"
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" bne- 2f \n"
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" stdcx. %4,0,%2 \n"
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" bne- 1b \n"
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"2: \n"
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: "=&r"(prev), "+m"(*mem)
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: "r"(mem), "r"(old), "r"(new)
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: "cr0");
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return prev;
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}
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static inline uint32_t cmpxchg32(uint32_t *mem, uint32_t old, uint32_t new)
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{
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uint32_t prev;
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sync();
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prev = __cmpxchg32(mem, old,new);
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sync();
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return prev;
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}
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#endif /* __TEST_ */
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#endif /* __CMPXCHG_H */
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