1 /* 2 * Copyright (c) 2017, 2020, 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 SHARE_RUNTIME_SAFEPOINTMECHANISM_HPP 26 #define SHARE_RUNTIME_SAFEPOINTMECHANISM_HPP 27 28 #include "runtime/globals.hpp" 29 #include "utilities/globalDefinitions.hpp" 30 #include "utilities/macros.hpp" 31 #include "utilities/sizes.hpp" 32 33 class JavaThread; 34 class Thread; 35 36 // This is the abstracted interface for the safepoint implementation 37 class SafepointMechanism : public AllStatic { 38 friend class StackWatermark; 39 static uintptr_t _poll_page_armed_value; 40 static uintptr_t _poll_page_disarmed_value; 41 42 static uintptr_t _poll_word_armed_value; 43 static uintptr_t _poll_word_disarmed_value; 44 45 static address _polling_page; 46 47 48 static inline void disarm_local_poll(JavaThread* thread); 49 50 static inline bool local_poll(Thread* thread); 51 static inline bool global_poll(); 52 53 static void process(JavaThread *thread); 54 static void process_if_requested_slow(JavaThread *thread); 55 56 static void default_initialize(); 57 58 static void pd_initialize() NOT_AIX({ default_initialize(); }); 59 60 static uintptr_t compute_poll_word(bool armed, uintptr_t stack_watermark); 61 62 const static intptr_t _poll_bit = 1; 63 public: 64 static inline bool local_poll_armed(JavaThread* thread); poll_bit()65 static intptr_t poll_bit() { return _poll_bit; } 66 get_polling_page()67 static address get_polling_page() { return _polling_page; } is_poll_address(address addr)68 static bool is_poll_address(address addr) { return addr >= _polling_page && addr < (_polling_page + os::vm_page_size()); } 69 70 struct ThreadData { 71 volatile uintptr_t _polling_word; 72 volatile uintptr_t _polling_page; 73 74 inline void set_polling_word(uintptr_t poll_value); 75 inline uintptr_t get_polling_word(); 76 77 inline void set_polling_page(uintptr_t poll_value); 78 inline uintptr_t get_polling_page(); 79 }; 80 81 // Call this method to see if this thread should block for a safepoint or process handshake. 82 static inline bool should_process(Thread* thread); 83 84 // Processes a pending requested operation. 85 static inline void process_if_requested(JavaThread* thread); 86 static inline void process_if_requested_with_exit_check(JavaThread* thread, bool check_asyncs); 87 // Compute what the poll values should be and install them. 88 static void update_poll_values(JavaThread* thread); 89 90 // Caller is responsible for using a memory barrier if needed. 91 static inline void arm_local_poll(JavaThread* thread); 92 // Release semantics 93 static inline void arm_local_poll_release(JavaThread* thread); 94 95 // Setup the selected safepoint mechanism 96 static void initialize(); 97 static void initialize_header(JavaThread* thread); 98 }; 99 100 #endif // SHARE_RUNTIME_SAFEPOINTMECHANISM_HPP 101