1 /*
 2  * Copyright (c) 2020, 2025, Oracle and/or its affiliates. All rights reserved.
 3  * Copyright (c) 2020, 2023, Huawei Technologies Co., Ltd. All rights reserved.
 4  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 5  *
 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
 8  * published by the Free Software Foundation.
 9  *
10  * This code is distributed in the hope that it will be useful, but WITHOUT
11  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13  * version 2 for more details (a copy is included in the LICENSE file that
14  * accompanied this code).
15  *
16  * You should have received a copy of the GNU General Public License version
17  * 2 along with this work; if not, write to the Free Software Foundation,
18  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
19  *
20  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
21  * or visit www.oracle.com if you need additional information or have any
22  * questions.
23  *
24  */
25 
26 #include "opto/c2_CodeStubs.hpp"
27 #include "opto/c2_MacroAssembler.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 5 * NativeInstruction::instruction_size;
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   RuntimeAddress callback_addr(stub);
43 
44   __ bind(entry());
45   InternalAddress safepoint_pc(__ pc() - __ offset() + _safepoint_offset);
46   __ relocate(safepoint_pc.rspec(), [&] {
47     // emits auipc + addi for address inside code cache
48     __ la(t0, safepoint_pc.target());
49   });
50   __ sd(t0, Address(xthread, JavaThread::saved_exception_pc_offset()));
51   // emits auipc + jr for address inside code cache
52   __ far_jump(callback_addr);
53 }
54 
55 int C2EntryBarrierStub::max_size() const {
56   // 4 bytes for alignment
57   return 4 * NativeInstruction::instruction_size + 4 + 4;
58 }
59 
60 void C2EntryBarrierStub::emit(C2_MacroAssembler& masm) {
61   __ bind(entry());
62   // emits auipc + jalr for address inside code cache
63   __ far_call(StubRoutines::method_entry_barrier());
64 
65   // emits auipc + jr assuming continuation is not near
66   __ j(continuation());
67 
68   // make guard value 4-byte aligned so that it can be accessed atomically
69   __ align(4);
70   __ bind(guard());
71   __ relocate(entry_guard_Relocation::spec());
72   __ emit_int32(0);  // nmethod guard value
73 }
74 
75 #undef __