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 #ifdef _LP64 77 int C2HandleAnonOMOwnerStub::max_size() const { 78 // Max size of stub has been determined by testing with 0, in which case 79 // C2CodeStubList::emit() will throw an assertion and report the actual size that 80 // is needed. 81 return DEBUG_ONLY(40) NOT_DEBUG(25); 82 } 83 84 void C2HandleAnonOMOwnerStub::emit(C2_MacroAssembler& masm) { 85 __ bind(entry()); 86 Register mon = monitor(); 87 Register t = tmp(); 88 __ movptr(t, Address(r15_thread, JavaThread::lock_id_offset())); 89 __ movptr(Address(mon, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)), t); 90 if (LockingMode == LM_LIGHTWEIGHT) { 91 __ subl(Address(r15_thread, JavaThread::lock_stack_top_offset()), oopSize); 92 #ifdef ASSERT 93 __ movl(t, Address(r15_thread, JavaThread::lock_stack_top_offset())); 94 __ movptr(Address(r15_thread, t), 0); 95 #endif 96 } else { 97 __ movptr(Address(mon, OM_OFFSET_NO_MONITOR_VALUE_TAG(stack_locker)), NULL_WORD); 98 __ decrementq(Address(r15_thread, JavaThread::held_monitor_count_offset())); 99 } 100 __ jmp(continuation()); 101 } 102 #endif 103 104 int C2FastUnlockLightweightStub::max_size() const { 105 return 128; 106 } 107 108 void C2FastUnlockLightweightStub::emit(C2_MacroAssembler& masm) { 109 assert(_t1 == rax, "must be"); 110 111 Label slow_path; 112 113 { // Restore lock-stack and handle the unlock in runtime. 114 115 __ bind(_push_and_slow_path); 116 #ifdef ASSERT 117 // The obj was only cleared in debug. 118 __ movl(_t1, Address(_thread, JavaThread::lock_stack_top_offset())); 119 __ movptr(Address(_thread, _t1), _obj); 120 #endif 121 __ addl(Address(_thread, JavaThread::lock_stack_top_offset()), oopSize); 122 } 123 124 { // Handle the unlock in runtime 125 126 __ bind(slow_path); 127 // set ZF=0 to indicate failure 128 __ orl(_t1, 1); 129 __ jmp(slow_path_continuation()); 130 } 131 132 { // Handle monitor medium path. 133 134 __ bind(_check_successor); 135 136 Label fix_zf_and_unlocked; 137 const Register monitor = _mark; 138 139 #ifndef _LP64 140 __ jmpb(slow_path); 141 #else // _LP64 142 // successor null check. 143 __ cmpptr(Address(monitor, OM_OFFSET_NO_MONITOR_VALUE_TAG(succ)), NULL_WORD); 144 __ jccb(Assembler::equal, slow_path); 145 146 // Release lock. 147 __ movptr(Address(monitor, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner)), NULL_WORD); 148 149 // Fence. 150 // Instead of MFENCE we use a dummy locked add of 0 to the top-of-stack. 151 __ lock(); __ addl(Address(rsp, 0), 0); 152 153 // Recheck successor. 154 __ cmpptr(Address(monitor, OM_OFFSET_NO_MONITOR_VALUE_TAG(succ)), NULL_WORD); 155 // Observed a successor after the release -> fence we have handed off the monitor 156 __ jccb(Assembler::notEqual, fix_zf_and_unlocked); 157 158 // Try to relock, if it fails the monitor has been handed over 159 // TODO: Caveat, this may fail due to deflation, which does 160 // not handle the monitor handoff. Currently only works 161 // due to the responsible thread. 162 __ xorptr(rax, rax); 163 __ movptr(_t2, Address(_thread, JavaThread::lock_id_offset())); 164 __ lock(); __ cmpxchgptr(_t2, Address(monitor, OM_OFFSET_NO_MONITOR_VALUE_TAG(owner))); 165 __ jccb (Assembler::equal, slow_path); 166 #endif 167 168 __ bind(fix_zf_and_unlocked); 169 __ xorl(rax, rax); 170 __ jmp(unlocked_continuation()); 171 } 172 } 173 174 #undef __