/*
* Copyright (C) 2005 Jakub Jermar
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* - Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* - 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.
* - The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/
#ifndef __ia32_BARRIER_H__
#define __ia32_BARRIER_H__
/*
* NOTE:
* No barriers for critical section (i.e. spinlock) on IA-32 are needed:
* - spinlock_lock() and spinlock_trylock() use serializing XCHG instruction
* - writes cannot pass reads on IA-32 => spinlock_unlock() needs no barriers
*/
/*
* Provisions are made to prevent compiler from reordering instructions itself.
*/
#define CS_ENTER_BARRIER() __asm__ volatile ("" ::: "memory")
#define CS_LEAVE_BARRIER() __asm__ volatile ("" ::: "memory")
#ifdef CONFIG_FENCES_P4
# define memory_barrier() __asm__ volatile ("mfence\n" ::: "memory")
# define read_barrier() __asm__ volatile ("lfence\n" ::: "memory")
# define write_barrier() __asm__ volatile ("sfence\n" ::: "memory")
#elif CONFIG_FENCES_P3
# define memory_barrier() __asm__ volatile ("\n" ::: "memory")
# define read_barrier() __asm__ volatile ("\n" ::: "memory")
# define write_barrier() __asm__ volatile ("sfence\n" ::: "memory")
#endif
#endif