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comparison src/os_cpu/linux_zero/vm/atomic_linux_zero.inline.hpp @ 22854:4ebc1b290dbd

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8067331: Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier Reviewed-by: dholmes, coleenp
author sgehwolf
date Tue, 24 Feb 2015 21:17:59 -0500
parents 63e54c37ac64
children
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22853:cae03a88934b 22854:4ebc1b290dbd
1 /* 1 /*
2 * Copyright (c) 2003, 2013, Oracle and/or its affiliates. All rights reserved. 2 * Copyright (c) 2003, 2014, Oracle and/or its affiliates. All rights reserved.
3 * Copyright 2007, 2008, 2011 Red Hat, Inc. 3 * Copyright 2007, 2008, 2011, 2015, Red Hat, Inc.
4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
5 * 5 *
6 * This code is free software; you can redistribute it and/or modify it 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 7 * under the terms of the GNU General Public License version 2 only, as
8 * published by the Free Software Foundation. 8 * published by the Free Software Foundation.
230 #else 230 #else
231 // __sync_lock_test_and_set is a bizarrely named atomic exchange 231 // __sync_lock_test_and_set is a bizarrely named atomic exchange
232 // operation. Note that some platforms only support this with the 232 // operation. Note that some platforms only support this with the
233 // limitation that the only valid value to store is the immediate 233 // limitation that the only valid value to store is the immediate
234 // constant 1. There is a test for this in JNI_CreateJavaVM(). 234 // constant 1. There is a test for this in JNI_CreateJavaVM().
235 return __sync_lock_test_and_set (dest, exchange_value); 235 jint result = __sync_lock_test_and_set (dest, exchange_value);
236 // All atomic operations are expected to be full memory barriers
237 // (see atomic.hpp). However, __sync_lock_test_and_set is not
238 // a full memory barrier, but an acquire barrier. Hence, this added
239 // barrier.
240 __sync_synchronize();
241 return result;
236 #endif // M68K 242 #endif // M68K
237 #endif // ARM 243 #endif // ARM
238 } 244 }
239 245
240 inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value, 246 inline intptr_t Atomic::xchg_ptr(intptr_t exchange_value,
243 return arm_lock_test_and_set(dest, exchange_value); 249 return arm_lock_test_and_set(dest, exchange_value);
244 #else 250 #else
245 #ifdef M68K 251 #ifdef M68K
246 return m68k_lock_test_and_set(dest, exchange_value); 252 return m68k_lock_test_and_set(dest, exchange_value);
247 #else 253 #else
248 return __sync_lock_test_and_set (dest, exchange_value); 254 intptr_t result = __sync_lock_test_and_set (dest, exchange_value);
255 __sync_synchronize();
256 return result;
249 #endif // M68K 257 #endif // M68K
250 #endif // ARM 258 #endif // ARM
251 } 259 }
252 260
253 inline void* Atomic::xchg_ptr(void* exchange_value, volatile void* dest) { 261 inline void* Atomic::xchg_ptr(void* exchange_value, volatile void* dest) {