1 /* 2 * Copyright (c) 2003, 2019, Oracle and/or its affiliates. All rights reserved. 3 * Copyright 2007, 2008, 2011, 2015, Red Hat, Inc. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 * 24 */ 25 26 #ifndef OS_CPU_LINUX_ZERO_ATOMIC_LINUX_ZERO_HPP 27 #define OS_CPU_LINUX_ZERO_ATOMIC_LINUX_ZERO_HPP 28 29 #include "runtime/os.hpp" 30 31 // Implementation of class atomic 32 33 template<size_t byte_size> 34 struct Atomic::PlatformAdd 35 : Atomic::AddAndFetch<Atomic::PlatformAdd<byte_size> > 36 { 37 template<typename I, typename D> 38 D add_and_fetch(I add_value, D volatile* dest, atomic_memory_order order) const; 39 }; 40 41 template<> 42 template<typename I, typename D> 43 inline D Atomic::PlatformAdd<4>::add_and_fetch(I add_value, D volatile* dest, 44 atomic_memory_order order) const { 45 STATIC_ASSERT(4 == sizeof(I)); 46 STATIC_ASSERT(4 == sizeof(D)); 47 48 return __sync_add_and_fetch(dest, add_value); 49 } 50 51 template<> 52 template<typename I, typename D> 53 inline D Atomic::PlatformAdd<8>::add_and_fetch(I add_value, D volatile* dest, 54 atomic_memory_order order) const { 55 STATIC_ASSERT(8 == sizeof(I)); 56 STATIC_ASSERT(8 == sizeof(D)); 57 return __sync_add_and_fetch(dest, add_value); 58 } 59 60 template<> 61 template<typename T> 62 inline T Atomic::PlatformXchg<4>::operator()(T exchange_value, 63 T volatile* dest, 64 atomic_memory_order order) const { 65 STATIC_ASSERT(4 == sizeof(T)); 66 // __sync_lock_test_and_set is a bizarrely named atomic exchange 67 // operation. Note that some platforms only support this with the 68 // limitation that the only valid value to store is the immediate 69 // constant 1. There is a test for this in JNI_CreateJavaVM(). 70 T result = __sync_lock_test_and_set (dest, exchange_value); 71 // All atomic operations are expected to be full memory barriers 72 // (see atomic.hpp). However, __sync_lock_test_and_set is not 73 // a full memory barrier, but an acquire barrier. Hence, this added 74 // barrier. 75 __sync_synchronize(); 76 return result; 77 } 78 79 template<> 80 template<typename T> 81 inline T Atomic::PlatformXchg<8>::operator()(T exchange_value, 82 T volatile* dest, 83 atomic_memory_order order) const { 84 STATIC_ASSERT(8 == sizeof(T)); 85 T result = __sync_lock_test_and_set (dest, exchange_value); 86 __sync_synchronize(); 87 return result; 88 } 89 90 // No direct support for cmpxchg of bytes; emulate using int. 91 template<> 92 struct Atomic::PlatformCmpxchg<1> : Atomic::CmpxchgByteUsingInt {}; 93 94 template<> 95 template<typename T> 96 inline T Atomic::PlatformCmpxchg<4>::operator()(T exchange_value, 97 T volatile* dest, 98 T compare_value, 99 atomic_memory_order order) const { 100 STATIC_ASSERT(4 == sizeof(T)); 101 return __sync_val_compare_and_swap(dest, compare_value, exchange_value); 102 } 103 104 template<> 105 template<typename T> 106 inline T Atomic::PlatformCmpxchg<8>::operator()(T exchange_value, 107 T volatile* dest, 108 T compare_value, 109 atomic_memory_order order) const { 110 STATIC_ASSERT(8 == sizeof(T)); 111 return __sync_val_compare_and_swap(dest, compare_value, exchange_value); 112 } 113 114 template<> 115 template<typename T> 116 inline T Atomic::PlatformLoad<8>::operator()(T const volatile* src) const { 117 STATIC_ASSERT(8 == sizeof(T)); 118 volatile int64_t dest; 119 os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(src), reinterpret_cast<volatile int64_t*>(&dest)); 120 return PrimitiveConversions::cast<T>(dest); 121 } 122 123 template<> 124 template<typename T> 125 inline void Atomic::PlatformStore<8>::operator()(T store_value, 126 T volatile* dest) const { 127 STATIC_ASSERT(8 == sizeof(T)); 128 os::atomic_copy64(reinterpret_cast<const volatile int64_t*>(&store_value), reinterpret_cast<volatile int64_t*>(dest)); 129 } 130 131 #endif // OS_CPU_LINUX_ZERO_ATOMIC_LINUX_ZERO_HPP