1/* 2 * Copyright (c) 2003, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#ifndef OS_CPU_BSD_X86_VM_ORDERACCESS_BSD_X86_INLINE_HPP 26#define OS_CPU_BSD_X86_VM_ORDERACCESS_BSD_X86_INLINE_HPP 27 28#include "runtime/atomic.hpp" 29#include "runtime/orderAccess.hpp" 30#include "runtime/os.hpp" 31 32// Compiler version last used for testing: clang 5.1 33// Please update this information when this file changes 34 35// A compiler barrier, forcing the C++ compiler to invalidate all memory assumptions 36static inline void compiler_barrier() { 37 __asm__ volatile ("" : : : "memory"); 38} 39 40// x86 is TSO and hence only needs a fence for storeload 41// However, a compiler barrier is still needed to prevent reordering 42// between volatile and non-volatile memory accesses. 43 44// Implementation of class OrderAccess. 45 46inline void OrderAccess::loadload() { compiler_barrier(); } 47inline void OrderAccess::storestore() { compiler_barrier(); } 48inline void OrderAccess::loadstore() { compiler_barrier(); } 49inline void OrderAccess::storeload() { fence(); } 50 51inline void OrderAccess::acquire() { compiler_barrier(); } 52inline void OrderAccess::release() { compiler_barrier(); } 53 54inline void OrderAccess::fence() { 55 if (os::is_MP()) { 56 // always use locked addl since mfence is sometimes expensive 57#ifdef AMD64 58 __asm__ volatile ("lock; addl $0,0(%%rsp)" : : : "cc", "memory"); 59#else 60 __asm__ volatile ("lock; addl $0,0(%%esp)" : : : "cc", "memory"); 61#endif 62 } 63 compiler_barrier(); 64} 65 66template<> 67inline void OrderAccess::specialized_release_store_fence<jbyte> (volatile jbyte* p, jbyte v) { 68 __asm__ volatile ( "xchgb (%2),%0" 69 : "=q" (v) 70 : "0" (v), "r" (p) 71 : "memory"); 72} 73template<> 74inline void OrderAccess::specialized_release_store_fence<jshort>(volatile jshort* p, jshort v) { 75 __asm__ volatile ( "xchgw (%2),%0" 76 : "=r" (v) 77 : "0" (v), "r" (p) 78 : "memory"); 79} 80template<> 81inline void OrderAccess::specialized_release_store_fence<jint> (volatile jint* p, jint v) { 82 __asm__ volatile ( "xchgl (%2),%0" 83 : "=r" (v) 84 : "0" (v), "r" (p) 85 : "memory"); 86} 87 88#ifdef AMD64 89template<> 90inline void OrderAccess::specialized_release_store_fence<jlong> (volatile jlong* p, jlong v) { 91 __asm__ volatile ( "xchgq (%2), %0" 92 : "=r" (v) 93 : "0" (v), "r" (p) 94 : "memory"); 95} 96#endif // AMD64 97 98template<> 99inline void OrderAccess::specialized_release_store_fence<jfloat> (volatile jfloat* p, jfloat v) { 100 release_store_fence((volatile jint*)p, jint_cast(v)); 101} 102template<> 103inline void OrderAccess::specialized_release_store_fence<jdouble>(volatile jdouble* p, jdouble v) { 104 release_store_fence((volatile jlong*)p, jlong_cast(v)); 105} 106 107#define VM_HAS_GENERALIZED_ORDER_ACCESS 1 108 109#endif // OS_CPU_BSD_X86_VM_ORDERACCESS_BSD_X86_INLINE_HPP 110