/*

 * Copyright (c) 2016, 2019, Oracle and/or its affiliates. All rights reserved.

 * Copyright (c) 2016 SAP SE. All rights reserved.

 * 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

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 */

#ifndef OS_CPU_LINUX_S390_ORDERACCESS_LINUX_S390_HPP

#define OS_CPU_LINUX_S390_ORDERACCESS_LINUX_S390_HPP

// Included in orderAccess.hpp header file.

#include "vm_version_s390.hpp"

// Implementation of class OrderAccess.

//

// machine barrier instructions:

//

//   - z_sync            two-way memory barrier, aka fence

//

// semantic barrier instructions:

// (as defined in orderAccess.hpp)

//

//   - z_release         orders Store|Store,    (maps to compiler barrier)

//                               Load|Store

//   - z_acquire         orders  Load|Store,    (maps to compiler barrier)

//                               Load|Load

//   - z_fence           orders Store|Store,    (maps to z_sync)

//                               Load|Store,

//                               Load|Load,

//                              Store|Load

//

// Only load-after-store-order is not guaranteed on z/Architecture, i.e. only 'fence'

// is needed.

// A compiler barrier, forcing the C++ compiler to invalidate all memory assumptions.

#define inlasm_compiler_barrier() __asm__ volatile ("" : : : "memory");

// "bcr 15, 0" is used as two way memory barrier.

#define inlasm_zarch_sync() __asm__ __volatile__ ("bcr 15, 0" : : : "memory");

// Release and acquire are empty on z/Architecture, but potential

// optimizations of gcc must be forbidden by OrderAccess::release and

// OrderAccess::acquire.

#define inlasm_zarch_release() inlasm_compiler_barrier()

#define inlasm_zarch_acquire() inlasm_compiler_barrier()

#define inlasm_zarch_fence()   inlasm_zarch_sync()

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

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

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

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

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

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

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

inline void OrderAccess::cross_modify_fence() { inlasm_zarch_sync(); }

template<size_t byte_size>

struct OrderAccess::PlatformOrderedLoad<byte_size, X_ACQUIRE>

{

  template <typename T>

  T operator()(const volatile T* p) const { T t = *p; inlasm_zarch_acquire(); return t; }

};

#undef inlasm_compiler_barrier

#undef inlasm_zarch_sync

#undef inlasm_zarch_release

#undef inlasm_zarch_acquire

#undef inlasm_zarch_fence

#endif // OS_CPU_LINUX_S390_ORDERACCESS_LINUX_S390_HPP