144 lines
3.1 KiB
C
144 lines
3.1 KiB
C
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/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
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*/
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#ifndef __ASM_ARC_CMPXCHG_H
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#define __ASM_ARC_CMPXCHG_H
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#include <linux/build_bug.h>
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#include <linux/types.h>
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#include <asm/barrier.h>
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#include <asm/smp.h>
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#ifdef CONFIG_ARC_HAS_LLSC
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/*
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* if (*ptr == @old)
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* *ptr = @new
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*/
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#define __cmpxchg(ptr, old, new) \
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({ \
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__typeof__(*(ptr)) _prev; \
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\
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__asm__ __volatile__( \
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"1: llock %0, [%1] \n" \
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" brne %0, %2, 2f \n" \
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" scond %3, [%1] \n" \
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" bnz 1b \n" \
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"2: \n" \
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: "=&r"(_prev) /* Early clobber prevent reg reuse */ \
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: "r"(ptr), /* Not "m": llock only supports reg */ \
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"ir"(old), \
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"r"(new) /* Not "ir": scond can't take LIMM */ \
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: "cc", \
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"memory"); /* gcc knows memory is clobbered */ \
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\
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_prev; \
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})
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#define arch_cmpxchg_relaxed(ptr, old, new) \
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({ \
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__typeof__(ptr) _p_ = (ptr); \
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__typeof__(*(ptr)) _o_ = (old); \
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__typeof__(*(ptr)) _n_ = (new); \
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__typeof__(*(ptr)) _prev_; \
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\
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switch(sizeof((_p_))) { \
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case 4: \
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_prev_ = __cmpxchg(_p_, _o_, _n_); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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_prev_; \
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})
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#else
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#define arch_cmpxchg(ptr, old, new) \
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({ \
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volatile __typeof__(ptr) _p_ = (ptr); \
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__typeof__(*(ptr)) _o_ = (old); \
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__typeof__(*(ptr)) _n_ = (new); \
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__typeof__(*(ptr)) _prev_; \
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unsigned long __flags; \
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\
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BUILD_BUG_ON(sizeof(_p_) != 4); \
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\
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/* \
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* spin lock/unlock provide the needed smp_mb() before/after \
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*/ \
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atomic_ops_lock(__flags); \
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_prev_ = *_p_; \
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if (_prev_ == _o_) \
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*_p_ = _n_; \
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atomic_ops_unlock(__flags); \
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_prev_; \
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})
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#endif
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/*
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* xchg
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*/
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#ifdef CONFIG_ARC_HAS_LLSC
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#define __xchg(ptr, val) \
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({ \
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__asm__ __volatile__( \
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" ex %0, [%1] \n" /* set new value */ \
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: "+r"(val) \
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: "r"(ptr) \
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: "memory"); \
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_val_; /* get old value */ \
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})
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#define arch_xchg_relaxed(ptr, val) \
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({ \
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__typeof__(ptr) _p_ = (ptr); \
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__typeof__(*(ptr)) _val_ = (val); \
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\
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switch(sizeof(*(_p_))) { \
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case 4: \
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_val_ = __xchg(_p_, _val_); \
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break; \
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default: \
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BUILD_BUG(); \
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} \
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_val_; \
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})
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#else /* !CONFIG_ARC_HAS_LLSC */
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/*
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* EX instructions is baseline and present in !LLSC too. But in this
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* regime it still needs use @atomic_ops_lock spinlock to allow interop
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* with cmpxchg() which uses spinlock in !LLSC
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* (llist.h use xchg and cmpxchg on sama data)
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*/
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#define arch_xchg(ptr, val) \
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({ \
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__typeof__(ptr) _p_ = (ptr); \
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__typeof__(*(ptr)) _val_ = (val); \
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\
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unsigned long __flags; \
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\
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atomic_ops_lock(__flags); \
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\
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__asm__ __volatile__( \
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" ex %0, [%1] \n" \
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: "+r"(_val_) \
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: "r"(_p_) \
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: "memory"); \
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\
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atomic_ops_unlock(__flags); \
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_val_; \
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})
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#endif
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#endif
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