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