1 /*
2 * Copyright (c) 2018, 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 "gc/shared/barrierSetNMethod.hpp"
27 #include "utilities/debug.hpp"
28
29 void BarrierSetNMethod::deoptimize(nmethod* nm, address* return_address_ptr) {
30 ShouldNotReachHere();
31 }
32
33 void BarrierSetNMethod::disarm(nmethod* nm) {
34 ShouldNotReachHere();
35 }
36
37 bool BarrierSetNMethod::is_armed(nmethod* nm) {
38 ShouldNotReachHere();
39 return false;
40 }
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1 /*
2 * Copyright (c) 2018, 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 #include "precompiled.hpp"
26 #include "code/codeCache.hpp"
27 #include "code/nativeInst.hpp"
28 #include "gc/shared/barrierSetNMethod.hpp"
29 #include "logging/log.hpp"
30 #include "memory/resourceArea.hpp"
31 #include "runtime/sharedRuntime.hpp"
32 #include "runtime/thread.hpp"
33 #include "utilities/align.hpp"
34 #include "utilities/debug.hpp"
35 #include "icache_aarch64.hpp"
36
37 class NativeNMethodBarrier: public NativeInstruction {
38 address instruction_address() const { return addr_at(0); }
39
40 int *guard_addr() {
41 return reinterpret_cast<int*>(instruction_address() + 10 * 4);
42 }
43
44 public:
45 int get_value() {
46 return Atomic::load_acquire(guard_addr());
47 }
48
49 void set_value(int value) {
50 Atomic::release_store(guard_addr(), value);
51 }
52
53 void verify() const;
54 };
55
56 // Store the instruction bitmask, bits and name for checking the barrier.
57 struct CheckInsn {
58 uint32_t mask;
59 uint32_t bits;
60 const char *name;
61 };
62
63 static const struct CheckInsn barrierInsn[] = {
64 { 0xff000000, 0x18000000, "ldr (literal)" },
65 { 0xfffff0ff, 0xd50330bf, "dmb" },
66 { 0xffc00000, 0xb9400000, "ldr"},
67 { 0x7f20001f, 0x6b00001f, "cmp"},
68 { 0xff00001f, 0x54000000, "b.eq"},
69 { 0xff800000, 0xd2800000, "mov"},
70 { 0xff800000, 0xf2800000, "movk"},
71 { 0xff800000, 0xf2800000, "movk"},
72 { 0xfffffc1f, 0xd63f0000, "blr"},
73 { 0xfc000000, 0x14000000, "b"}
74 };
75
76 // The encodings must match the instructions emitted by
77 // BarrierSetAssembler::nmethod_entry_barrier. The matching ignores the specific
78 // register numbers and immediate values in the encoding.
79 void NativeNMethodBarrier::verify() const {
80 intptr_t addr = (intptr_t) instruction_address();
81 for(unsigned int i = 0; i < sizeof(barrierInsn)/sizeof(struct CheckInsn); i++ ) {
82 uint32_t inst = *((uint32_t*) addr);
83 if ((inst & barrierInsn[i].mask) != barrierInsn[i].bits) {
84 tty->print_cr("Addr: " INTPTR_FORMAT " Code: 0x%x", addr, inst);
85 fatal("not an %s instruction.", barrierInsn[i].name);
86 }
87 addr +=4;
88 }
89 }
90
91
92 /* We're called from an nmethod when we need to deoptimize it. We do
93 this by throwing away the nmethod's frame and jumping to the
94 ic_miss stub. This looks like there has been an IC miss at the
95 entry of the nmethod, so we resolve the call, which will fall back
96 to the interpreter if the nmethod has been unloaded. */
97 void BarrierSetNMethod::deoptimize(nmethod* nm, address* return_address_ptr) {
98
99 typedef struct {
100 intptr_t *sp; intptr_t *fp; address lr; address pc;
101 } frame_pointers_t;
102
103 frame_pointers_t *new_frame = (frame_pointers_t *)(return_address_ptr - 5);
104
105 JavaThread *thread = (JavaThread*)Thread::current();
106 RegisterMap reg_map(thread, false);
107 frame frame = thread->last_frame();
108
109 assert(frame.is_compiled_frame() || frame.is_native_frame(), "must be");
110 assert(frame.cb() == nm, "must be");
111 frame = frame.sender(®_map);
112
113 LogTarget(Trace, nmethod, barrier) out;
114 if (out.is_enabled()) {
115 Thread* thread = Thread::current();
116 assert(thread->is_Java_thread(), "must be JavaThread");
117 JavaThread* jth = (JavaThread*) thread;
118 ResourceMark mark;
119 log_trace(nmethod, barrier)("deoptimize(nmethod: %s(%p), return_addr: %p, osr: %d, thread: %p(%s), making rsp: %p) -> %p",
120 nm->method()->name_and_sig_as_C_string(),
121 nm, *(address *) return_address_ptr, nm->is_osr_method(), jth,
122 jth->get_thread_name(), frame.sp(), nm->verified_entry_point());
123 }
124
125 new_frame->sp = frame.sp();
126 new_frame->fp = frame.fp();
127 new_frame->lr = frame.pc();
128 new_frame->pc = SharedRuntime::get_handle_wrong_method_stub();
129 }
130
131 // This is the offset of the entry barrier from where the frame is completed.
132 // If any code changes between the end of the verified entry where the entry
133 // barrier resides, and the completion of the frame, then
134 // NativeNMethodCmpBarrier::verify() will immediately complain when it does
135 // not find the expected native instruction at this offset, which needs updating.
136 // Note that this offset is invariant of PreserveFramePointer.
137
138 static const int entry_barrier_offset = -4 * 11;
139
140 static NativeNMethodBarrier* native_nmethod_barrier(nmethod* nm) {
141 address barrier_address = nm->code_begin() + nm->frame_complete_offset() + entry_barrier_offset;
142 NativeNMethodBarrier* barrier = reinterpret_cast<NativeNMethodBarrier*>(barrier_address);
143 debug_only(barrier->verify());
144 return barrier;
145 }
146
147 void BarrierSetNMethod::disarm(nmethod* nm) {
148 if (!supports_entry_barrier(nm)) {
149 return;
150 }
151
152 // Disarms the nmethod guard emitted by BarrierSetAssembler::nmethod_entry_barrier.
153 // Symmetric "LDR; DMB ISHLD" is in the nmethod barrier.
154 NativeNMethodBarrier* barrier = native_nmethod_barrier(nm);
155
156 barrier->set_value(disarmed_value());
157 }
158
159 bool BarrierSetNMethod::is_armed(nmethod* nm) {
160 if (!supports_entry_barrier(nm)) {
161 return false;
162 }
163
164 NativeNMethodBarrier* barrier = native_nmethod_barrier(nm);
165 return barrier->get_value() != disarmed_value();
166 }
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