/*

 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved.

 * Copyright 2007, 2008, 2009 Red Hat, Inc.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#ifndef OS_CPU_LINUX_ZERO_ORDERACCESS_LINUX_ZERO_HPP

#define OS_CPU_LINUX_ZERO_ORDERACCESS_LINUX_ZERO_HPP

// Included in orderAccess.hpp header file.

#ifdef ARM

/*

 * ARM Kernel helper for memory barrier.

 * Using __asm __volatile ("":::"memory") does not work reliable on ARM

 * and gcc __sync_synchronize(); implementation does not use the kernel

 * helper for all gcc versions so it is unreliable to use as well.

 */

typedef void (__kernel_dmb_t) (void);

#define __kernel_dmb (*(__kernel_dmb_t *) 0xffff0fa0)

#define FULL_MEM_BARRIER __kernel_dmb()

#define LIGHT_MEM_BARRIER __kernel_dmb()

#else // ARM

#define FULL_MEM_BARRIER __sync_synchronize()

#ifdef PPC

#ifdef __NO_LWSYNC__

#define LIGHT_MEM_BARRIER __asm __volatile ("sync":::"memory")

#else

#define LIGHT_MEM_BARRIER __asm __volatile ("lwsync":::"memory")

#endif

#else // PPC

#ifdef ALPHA

#define LIGHT_MEM_BARRIER __sync_synchronize()

#else // ALPHA

#define LIGHT_MEM_BARRIER __asm __volatile ("":::"memory")

#endif // ALPHA

#endif // PPC

#endif // ARM

// Note: What is meant by LIGHT_MEM_BARRIER is a barrier which is sufficient

// to provide TSO semantics, i.e. StoreStore | LoadLoad | LoadStore.

inline void OrderAccess::loadload()   { LIGHT_MEM_BARRIER; }

inline void OrderAccess::storestore() { LIGHT_MEM_BARRIER; }

inline void OrderAccess::loadstore()  { LIGHT_MEM_BARRIER; }

inline void OrderAccess::storeload()  { FULL_MEM_BARRIER;  }

inline void OrderAccess::acquire()    { LIGHT_MEM_BARRIER; }

inline void OrderAccess::release()    { LIGHT_MEM_BARRIER; }

inline void OrderAccess::fence()      { FULL_MEM_BARRIER;  }

inline void OrderAccess::cross_modify_fence()            { }

#endif // OS_CPU_LINUX_ZERO_ORDERACCESS_LINUX_ZERO_HPP