159 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			159 lines
		
	
	
		
			4.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*	$NetBSD: atomic_init_testset.c,v 1.7 2009/12/14 00:39:00 matt Exp $	*/
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/*-
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 * Copyright (c) 2008 The NetBSD Foundation, Inc.
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 * All rights reserved.
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 *
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 * Redistribution and use in source and binary forms, with or without
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 * modification, are permitted provided that the following conditions
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 * are met:
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 * 1. Redistributions of source code must retain the above copyright
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 *    notice, this list of conditions and the following disclaimer.
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 * 2. Redistributions in binary form must reproduce the above copyright
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 *    notice, this list of conditions and the following disclaimer in the
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 *    documentation and/or other materials provided with the distribution.
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 *
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 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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 * POSSIBILITY OF SUCH DAMAGE.
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 */
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/*
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 * libc glue for atomic operations where the hardware does not provide
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 * compare-and-swap.  It's assumed that this will only be used on 32-bit
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 * platforms.
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 *
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 * This should be compiled with '-fno-reorder-blocks -fomit-frame-pointer'
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 * if using gcc.
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 */
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#include <sys/cdefs.h>
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__RCSID("$NetBSD: atomic_init_testset.c,v 1.7 2009/12/14 00:39:00 matt Exp $");
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#include "atomic_op_namespace.h"
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#include <sys/types.h>
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#include <sys/atomic.h>
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#include <sys/lock.h>
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#include <sys/ras.h>
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#include <sys/sysctl.h>
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#include <string.h>
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#define	I2	__SIMPLELOCK_UNLOCKED, __SIMPLELOCK_UNLOCKED,
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#define	I16	I2 I2 I2 I2 I2 I2 I2 I2
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#define	I128	I16 I16 I16 I16 I16 I16 I16 I16
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static __cpu_simple_lock_t atomic_locks[128] = { I128 };
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#ifdef	__HAVE_ASM_ATOMIC_CAS_UP
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extern uint32_t _atomic_cas_up(volatile uint32_t *, uint32_t, uint32_t);
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#else
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static uint32_t _atomic_cas_up(volatile uint32_t *, uint32_t, uint32_t);
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#endif
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static uint32_t (*_atomic_cas_fn)(volatile uint32_t *, uint32_t, uint32_t) =
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    _atomic_cas_up;
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void	__libc_atomic_init(void) __attribute__ ((visibility("hidden")));
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RAS_DECL(_atomic_cas);
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#ifndef	__HAVE_ASM_ATOMIC_CAS_UP
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static uint32_t
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_atomic_cas_up(volatile uint32_t *ptr, uint32_t old, uint32_t new)
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{
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	uint32_t ret;
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	RAS_START(_atomic_cas);
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	ret = *ptr;
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	if (__predict_false(ret != old)) {
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		return ret;
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	}
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	*ptr = new;
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	RAS_END(_atomic_cas);
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	return ret;
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}
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#endif
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static uint32_t
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_atomic_cas_mp(volatile uint32_t *ptr, uint32_t old, uint32_t new)
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{
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	__cpu_simple_lock_t *lock;
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	uint32_t ret;
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	lock = &atomic_locks[((uintptr_t)ptr >> 3) & 127];
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	__cpu_simple_lock(lock);
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	ret = *ptr;
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	if (__predict_true(ret == old)) {
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		*ptr = new;
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	}
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	__cpu_simple_unlock(lock);
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	return ret;
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}
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uint32_t
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_atomic_cas_32(volatile uint32_t *ptr, uint32_t old, uint32_t new)
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{
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	return (*_atomic_cas_fn)(ptr, old, new);
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}
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void
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__libc_atomic_init(void)
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{
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#if !defined(__minix)
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	int ncpu, mib[2];
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	size_t len;
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#endif
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	_atomic_cas_fn = _atomic_cas_mp;
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#if !defined(__minix)
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	mib[0] = CTL_HW;
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	mib[1] = HW_NCPU; 
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	len = sizeof(ncpu);
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	if (sysctl(mib, 2, &ncpu, &len, NULL, 0) == -1)
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		return;
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	if (ncpu > 1)
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		return;
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	if (rasctl(RAS_ADDR(_atomic_cas), RAS_SIZE(_atomic_cas),
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	    RAS_INSTALL) == 0) {
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		_atomic_cas_fn = _atomic_cas_up;
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		return;
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	}
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#endif
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}
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#undef atomic_cas_32
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#undef atomic_cas_uint
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#undef atomic_cas_ulong
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#undef atomic_cas_ptr
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atomic_op_alias(atomic_cas_32,_atomic_cas_32)
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atomic_op_alias(atomic_cas_uint,_atomic_cas_32)
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__strong_alias(_atomic_cas_uint,_atomic_cas_32)
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atomic_op_alias(atomic_cas_ulong,_atomic_cas_32)
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__strong_alias(_atomic_cas_ulong,_atomic_cas_32)
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atomic_op_alias(atomic_cas_ptr,_atomic_cas_32)
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__strong_alias(_atomic_cas_ptr,_atomic_cas_32)
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atomic_op_alias(atomic_cas_32_ni,_atomic_cas_32)
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__strong_alias(_atomic_cas_32_ni,_atomic_cas_32)
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atomic_op_alias(atomic_cas_uint_ni,_atomic_cas_32)
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__strong_alias(_atomic_cas_uint_ni,_atomic_cas_32)
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atomic_op_alias(atomic_cas_ulong_ni,_atomic_cas_32)
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__strong_alias(_atomic_cas_ulong_ni,_atomic_cas_32)
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atomic_op_alias(atomic_cas_ptr_ni,_atomic_cas_32)
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__strong_alias(_atomic_cas_ptr_ni,_atomic_cas_32)
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