1 /* 2 * Copyright (c) 2020, 2024, 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 #include "precompiled.hpp" 26 #include "opto/c2_MacroAssembler.hpp" 27 #include "opto/c2_CodeStubs.hpp" 28 #include "runtime/objectMonitor.hpp" 29 #include "runtime/sharedRuntime.hpp" 30 #include "runtime/stubRoutines.hpp" 31 32 #define __ masm. 33 34 int C2SafepointPollStub::max_size() const { 35 return 33; 36 } 37 38 void C2SafepointPollStub::emit(C2_MacroAssembler& masm) { 39 assert(SharedRuntime::polling_page_return_handler_blob() != nullptr, 40 "polling page return stub not created yet"); 41 address stub = SharedRuntime::polling_page_return_handler_blob()->entry_point(); 42 43 RuntimeAddress callback_addr(stub); 44 45 __ bind(entry()); 46 InternalAddress safepoint_pc(masm.pc() - masm.offset() + _safepoint_offset); 47 #ifdef _LP64 48 __ lea(rscratch1, safepoint_pc); 49 __ movptr(Address(r15_thread, JavaThread::saved_exception_pc_offset()), rscratch1); 50 #else 51 const Register tmp1 = rcx; 52 const Register tmp2 = rdx; 53 __ push(tmp1); 54 __ push(tmp2); 55 56 __ lea(tmp1, safepoint_pc); 57 __ get_thread(tmp2); 58 __ movptr(Address(tmp2, JavaThread::saved_exception_pc_offset()), tmp1); 59 60 __ pop(tmp2); 61 __ pop(tmp1); 62 #endif 63 __ jump(callback_addr); 64 } 65 66 int C2EntryBarrierStub::max_size() const { 67 return 10; 68 } 69 70 void C2EntryBarrierStub::emit(C2_MacroAssembler& masm) { 71 __ bind(entry()); 72 __ call(RuntimeAddress(StubRoutines::method_entry_barrier())); 73 __ jmp(continuation(), false /* maybe_short */); 74 } 75 76 int C2FastUnlockLightweightStub::max_size() const { 77 return 128; 78 } 79 80 void C2FastUnlockLightweightStub::emit(C2_MacroAssembler& masm) { 81 assert(_t == rax, "must be"); 82 83 Label restore_held_monitor_count_and_slow_path; 84 85 { // Restore lock-stack and handle the unlock in runtime. 86 87 __ bind(_push_and_slow_path); 88 #ifdef ASSERT 89 // The obj was only cleared in debug. 90 __ movl(_t, Address(_thread, JavaThread::lock_stack_top_offset())); 91 __ movptr(Address(_thread, _t), _obj); 92 #endif 93 __ addl(Address(_thread, JavaThread::lock_stack_top_offset()), oopSize); 94 } 95 96 { // Restore held monitor count and slow path. 97 98 __ bind(restore_held_monitor_count_and_slow_path); 99 __ bind(_slow_path); 100 // Restore held monitor count. 101 __ increment(Address(_thread, JavaThread::held_monitor_count_offset())); 102 // increment will always result in ZF = 0 (no overflows). 103 __ jmp(slow_path_continuation()); 104 } 105 106 { // Handle monitor medium path. 107 108 __ bind(_check_successor); 109 110 Label fix_zf_and_unlocked; 111 const Register monitor = _mark; 112 113 #ifndef _LP64 114 __ jmpb(restore_held_monitor_count_and_slow_path); 115 #else // _LP64 116 const ByteSize monitor_tag = in_ByteSize(UseObjectMonitorTable ? 0 : checked_cast<int>(markWord::monitor_value)); 117 const Address succ_address{monitor, ObjectMonitor::succ_offset() - monitor_tag}; 118 const Address owner_address{monitor, ObjectMonitor::owner_offset() - monitor_tag}; 119 120 // successor null check. 121 __ cmpptr(succ_address, NULL_WORD); 122 __ jccb(Assembler::equal, restore_held_monitor_count_and_slow_path); 123 124 // Release lock. 125 __ movptr(owner_address, NULL_WORD); 126 127 // Fence. 128 // Instead of MFENCE we use a dummy locked add of 0 to the top-of-stack. 129 __ lock(); __ addl(Address(rsp, 0), 0); 130 131 // Recheck successor. 132 __ cmpptr(succ_address, NULL_WORD); 133 // Observed a successor after the release -> fence we have handed off the monitor 134 __ jccb(Assembler::notEqual, fix_zf_and_unlocked); 135 136 // Try to relock, if it fails the monitor has been handed over 137 // TODO: Caveat, this may fail due to deflation, which does 138 // not handle the monitor handoff. Currently only works 139 // due to the responsible thread. 140 __ xorptr(rax, rax); 141 __ lock(); __ cmpxchgptr(_thread, owner_address); 142 __ jccb (Assembler::equal, restore_held_monitor_count_and_slow_path); 143 #endif 144 145 __ bind(fix_zf_and_unlocked); 146 __ xorl(rax, rax); 147 __ jmp(unlocked_continuation()); 148 } 149 } 150 151 #undef __ --- EOF ---