1 /*
2 * Copyright (c) 1997, 2025, Oracle and/or its affiliates. All rights reserved.
3 * Copyright (c) 2021, Azul Systems, Inc. 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 #ifndef SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
27 #define SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP
28
29 // No interfaceSupport.hpp
30
31 #include "gc/shared/gc_globals.hpp"
32 #include "runtime/globals.hpp"
33 #include "runtime/handles.inline.hpp"
34 #include "runtime/javaThread.inline.hpp"
35 #include "runtime/mutexLocker.hpp"
36 #include "runtime/orderAccess.hpp"
37 #include "runtime/os.hpp"
38 #include "runtime/safepointMechanism.inline.hpp"
39 #include "runtime/safepointVerifiers.hpp"
40 #include "runtime/threadWXSetters.inline.hpp"
41 #include "runtime/vmOperations.hpp"
42 #include "utilities/globalDefinitions.hpp"
43 #include "utilities/macros.hpp"
44 #include "utilities/preserveException.hpp"
45
46 // Wrapper for all entry points to the virtual machine.
47
48 // InterfaceSupport provides functionality used by the VM_LEAF_BASE and
49 // VM_ENTRY_BASE macros. These macros are used to guard entry points into
50 // the VM and perform checks upon leave of the VM.
51
52
53 class InterfaceSupport: AllStatic {
54 # ifdef ASSERT
55 public:
56 static unsigned int _scavenge_alot_counter;
57 static unsigned int _fullgc_alot_counter;
58 static intx _fullgc_alot_invocation;
59
60 // Helper methods used to implement +ScavengeALot and +FullGCALot
61 static void check_gc_alot() { if (ScavengeALot || FullGCALot) gc_alot(); }
62 static void gc_alot();
63
64 static void walk_stack_from(vframe* start_vf);
65 static void walk_stack();
66
67 static void zombieAll();
68 static void deoptimizeAll();
69 static void verify_stack();
70 static void verify_last_frame();
71 # endif
72 };
73
74
75 // Basic class for all thread transition classes.
76
77 class ThreadStateTransition : public StackObj {
78 protected:
79 JavaThread* _thread;
80
81 public:
82 ThreadStateTransition(JavaThread *thread) : _thread(thread) {
83 assert(thread != nullptr, "must be active Java thread");
84 assert(thread == Thread::current(), "must be current thread");
85 }
86
87 static inline void transition_from_java(JavaThread *thread, JavaThreadState to) {
88 assert(thread->thread_state() == _thread_in_Java, "coming from wrong thread state");
89 assert(to == _thread_in_vm || to == _thread_in_native, "invalid transition");
90 thread->set_thread_state(to);
91 }
92
93 // We never install asynchronous exceptions when coming (back) in to the runtime
94 // from native code because the runtime is not set up to handle exceptions floating
95 // around at arbitrary points.
96 static inline void transition_from_native(JavaThread *thread, JavaThreadState to, bool check_asyncs = true) {
97 assert(thread->thread_state() == _thread_in_native, "coming from wrong thread state");
98 assert(to == _thread_in_vm || to == _thread_in_Java, "invalid transition");
99 assert(!thread->has_last_Java_frame() || thread->frame_anchor()->walkable(), "Unwalkable stack in native transition");
100
101 if (!UseSystemMemoryBarrier) {
102 thread->set_thread_state_fence(_thread_in_vm);
103 } else {
104 thread->set_thread_state(_thread_in_vm);
105 }
106 SafepointMechanism::process_if_requested_with_exit_check(thread, to != _thread_in_Java ? false : check_asyncs);
107 thread->set_thread_state(to);
108 }
109
110 static inline void transition_from_vm(JavaThread *thread, JavaThreadState to, bool check_asyncs = true) {
111 assert(thread->thread_state() == _thread_in_vm, "coming from wrong thread state");
112 if (to == _thread_in_Java) {
113 SafepointMechanism::process_if_requested_with_exit_check(thread, check_asyncs);
114 thread->set_thread_state(to);
115 } else {
116 assert(to == _thread_in_native || to == _thread_blocked, "invalid transition");
117 // Check NoSafepointVerifier. This also clears unhandled oops if CheckUnhandledOops is used.
118 thread->check_possible_safepoint();
119
120 // Once we are in native/blocked vm expects stack to be walkable
121 thread->frame_anchor()->make_walkable();
122 OrderAccess::storestore(); // Keep thread_state change and make_walkable() separate.
123 thread->set_thread_state(to);
124 }
125 }
126 };
127
128 class ThreadInVMfromJava : public ThreadStateTransition {
129 bool _check_asyncs;
130 public:
131 ThreadInVMfromJava(JavaThread* thread, bool check_asyncs = true) : ThreadStateTransition(thread), _check_asyncs(check_asyncs) {
132 transition_from_java(thread, _thread_in_vm);
133 }
134 ~ThreadInVMfromJava() {
135 if (_thread->stack_overflow_state()->stack_yellow_reserved_zone_disabled()) {
136 _thread->stack_overflow_state()->enable_stack_yellow_reserved_zone();
137 }
138 // We prevent asynchronous exceptions from being installed on return to Java in situations
139 // where we can't tolerate them. See bugs: 4324348, 4854693, 4998314, 5040492, 5050705.
140 transition_from_vm(_thread, _thread_in_Java, _check_asyncs);
141 }
142 };
143
144
145 class ThreadInVMfromUnknown {
146 JavaThread* _thread;
147 public:
148 ThreadInVMfromUnknown() : _thread(nullptr) {
149 Thread* t = Thread::current();
150 if (t->is_Java_thread()) {
151 JavaThread* t2 = JavaThread::cast(t);
152 if (t2->thread_state() == _thread_in_native) {
153 _thread = t2;
154 ThreadStateTransition::transition_from_native(t2, _thread_in_vm);
155 // Used to have a HandleMarkCleaner but that is dangerous as
156 // it could free a handle in our (indirect, nested) caller.
157 // We expect any handles will be short lived and figure we
158 // don't need an actual HandleMark.
159 }
160 }
161 }
162 ~ThreadInVMfromUnknown() {
163 if (_thread) {
164 ThreadStateTransition::transition_from_vm(_thread, _thread_in_native);
165 }
166 }
167 };
168
169
170 class ThreadInVMfromNative : public ThreadStateTransition {
171 ResetNoHandleMark __rnhm;
172 public:
173 ThreadInVMfromNative(JavaThread* thread) : ThreadStateTransition(thread) {
174 transition_from_native(thread, _thread_in_vm);
175 }
176 ~ThreadInVMfromNative() {
177 // We cannot assert !_thread->owns_locks() since we have valid cases where
178 // we call known native code using this wrapper holding locks.
179 transition_from_vm(_thread, _thread_in_native);
180 }
181 };
182
183
184 class ThreadToNativeFromVM : public ThreadStateTransition {
185 public:
186 ThreadToNativeFromVM(JavaThread *thread) : ThreadStateTransition(thread) {
187 assert(!thread->owns_locks(), "must release all locks when leaving VM");
188 transition_from_vm(thread, _thread_in_native);
189 }
190 ~ThreadToNativeFromVM() {
191 transition_from_native(_thread, _thread_in_vm);
192 assert(!_thread->is_pending_jni_exception_check(), "Pending JNI Exception Check");
193 // We don't need to clear_walkable because it will happen automagically when we return to java
194 }
195 };
196
197 // Perform a transition to _thread_blocked and take a call-back to be executed before
198 // SafepointMechanism::process_if_requested when returning to the VM. This allows us
199 // to perform an "undo" action if we might block processing a safepoint/handshake operation
200 // (such as thread suspension).
201 template <typename PRE_PROC = void(JavaThread*)>
202 class ThreadBlockInVMPreprocess : public ThreadStateTransition {
203 private:
204 PRE_PROC& _pr;
205 bool _allow_suspend;
206 public:
207 ThreadBlockInVMPreprocess(JavaThread* thread, PRE_PROC& pr, bool allow_suspend = false)
208 : ThreadStateTransition(thread), _pr(pr), _allow_suspend(allow_suspend) {
209 transition_from_vm(thread, _thread_blocked);
210 }
211 ~ThreadBlockInVMPreprocess() {
212 assert(_thread->thread_state() == _thread_blocked, "coming from wrong thread state");
213 // Change back to _thread_in_vm and ensure it is seen by the VM thread.
214 _thread->set_thread_state_fence(_thread_in_vm);
215
216 if (SafepointMechanism::should_process(_thread, _allow_suspend)) {
217 _pr(_thread);
218 SafepointMechanism::process_if_requested(_thread, _allow_suspend, false /* check_async_exception */);
219 }
220 }
221 };
222
223 class ThreadBlockInVM : public ThreadBlockInVMPreprocess<> {
224 public:
225 ThreadBlockInVM(JavaThread* thread, bool allow_suspend = false)
226 : ThreadBlockInVMPreprocess(thread, emptyOp, allow_suspend) {}
227 private:
228 static void emptyOp(JavaThread* current) {}
229 };
230
231
232 // Debug class instantiated in JRT_ENTRY macro.
233 // Can be used to verify properties on enter/exit of the VM.
234
235 #ifdef ASSERT
236 class VMEntryWrapper {
237 public:
238 VMEntryWrapper();
239 ~VMEntryWrapper();
240 };
241
242
243 class VMNativeEntryWrapper {
244 public:
245 VMNativeEntryWrapper();
246 ~VMNativeEntryWrapper();
247 };
248
249 #endif // ASSERT
250
251 // LEAF routines do not lock, GC or throw exceptions
252
253 // On macos/aarch64 we need to maintain the W^X state of the thread. So we
254 // take WXWrite on the enter to VM from the "outside" world, so the rest of JVM
255 // code can assume writing (but not executing) codecache is always possible
256 // without preliminary actions.
257 // JavaThread state should be changed only after taking WXWrite. The state
258 // change may trigger a safepoint, that would need WXWrite to do bookkeeping
259 // in the codecache.
260
261 #define VM_LEAF_BASE(result_type, header) \
262 DEBUG_ONLY(NoHandleMark __hm;) \
263 os::verify_stack_alignment(); \
264 /* begin of body */
265
266 #define VM_ENTRY_BASE_FROM_LEAF(result_type, header, thread) \
267 DEBUG_ONLY(ResetNoHandleMark __rnhm;) \
268 HandleMarkCleaner __hm(thread); \
269 JavaThread* THREAD = thread; /* For exception macros. */ \
270 os::verify_stack_alignment(); \
271 /* begin of body */
272
273
274 // ENTRY routines may lock, GC and throw exceptions
275
276 #define VM_ENTRY_BASE(result_type, header, thread) \
277 HandleMarkCleaner __hm(thread); \
278 JavaThread* THREAD = thread; /* For exception macros. */ \
279 os::verify_stack_alignment(); \
280 /* begin of body */
281
282 #define JRT_ENTRY(result_type, header) \
283 result_type header { \
284 assert(current == JavaThread::current(), "Must be"); \
285 ThreadInVMfromJava __tiv(current); \
286 MACOS_AARCH64_ONLY( \
287 static WXMode wx_mode = DefaultWXWriteMode; \
288 ThreadWXEnable __wx(&wx_mode, current); \
289 ) \
290 VM_ENTRY_BASE(result_type, header, current) \
291 DEBUG_ONLY(VMEntryWrapper __vew;)
292
293 // JRT_LEAF currently can be called from either _thread_in_Java or
294 // _thread_in_native mode.
295 //
296 // JRT_LEAF rules:
297 // A JRT_LEAF method may not interfere with safepointing by
298 // 1) acquiring or blocking on a Mutex or JavaLock - checked
299 // 2) allocating heap memory - checked
300 // 3) executing a VM operation - checked
301 // 4) executing a system call (including malloc) that could block or grab a lock
302 // 5) invoking GC
303 // 6) reaching a safepoint
304 // 7) running too long
305 // Nor may any method it calls.
306
307 #define JRT_LEAF(result_type, header) \
308 result_type header { \
309 VM_LEAF_BASE(result_type, header) \
310 DEBUG_ONLY(NoSafepointVerifier __nsv;)
311
312
313 #define JRT_ENTRY_NO_ASYNC(result_type, header) \
314 result_type header { \
315 assert(current == JavaThread::current(), "Must be"); \
316 ThreadInVMfromJava __tiv(current, false /* check asyncs */); \
317 MACOS_AARCH64_ONLY( \
318 static WXMode wx_mode = DefaultWXWriteMode; \
319 ThreadWXEnable __wx(&wx_mode, current); \
320 ) \
321 VM_ENTRY_BASE(result_type, header, current) \
322 DEBUG_ONLY(VMEntryWrapper __vew;)
323
324 // Same as JRT Entry but allows for return value after the safepoint
325 // to get back into Java from the VM
326 #define JRT_BLOCK_ENTRY(result_type, header) \
327 result_type header { \
328 assert(current == JavaThread::current(), "Must be"); \
329 MACOS_AARCH64_ONLY( \
330 static WXMode wx_mode = DefaultWXWriteMode; \
331 ThreadWXEnable __wx(&wx_mode, current); \
332 ) \
333 HandleMarkCleaner __hm(current);
334
335 #define JRT_BLOCK \
336 { \
337 assert(current == JavaThread::current(), "Must be"); \
338 ThreadInVMfromJava __tiv(current); \
339 JavaThread* THREAD = current; /* For exception macros. */ \
340 DEBUG_ONLY(VMEntryWrapper __vew;)
341
342 #define JRT_BLOCK_NO_ASYNC \
343 { \
344 assert(current == JavaThread::current(), "Must be"); \
345 ThreadInVMfromJava __tiv(current, false /* check asyncs */); \
346 JavaThread* THREAD = current; /* For exception macros. */ \
347 DEBUG_ONLY(VMEntryWrapper __vew;)
348
349 #define JRT_BLOCK_END }
350
351 #define JRT_END }
352
353 // Definitions for JNI
354 //
355 // As the JNIEnv can be passed from external native code we validate
356 // it in debug builds, primarily for our own testing. In general JNI
357 // does not attempt to detect programming errors and a bad JNIEnv may
358 // not even be readable.
359
360 #define JNI_ENTRY(result_type, header) \
361 JNI_ENTRY_NO_PRESERVE(result_type, header) \
362 WeakPreserveExceptionMark __wem(thread);
363
364 #define JNI_ENTRY_NO_PRESERVE(result_type, header) \
365 extern "C" { \
366 result_type JNICALL header { \
367 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
368 assert(thread == Thread::current(), "JNIEnv is only valid in same thread"); \
369 ThreadInVMfromNative __tiv(thread); \
370 MACOS_AARCH64_ONLY( \
371 static WXMode wx_mode = DefaultWXWriteMode; \
372 ThreadWXEnable __wx(&wx_mode, thread); \
373 ) \
374 DEBUG_ONLY(VMNativeEntryWrapper __vew;) \
375 VM_ENTRY_BASE(result_type, header, thread)
376
377
378 #define JNI_LEAF(result_type, header) \
379 extern "C" { \
380 result_type JNICALL header { \
381 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
382 assert(thread == Thread::current(), "JNIEnv is only valid in same thread"); \
383 VM_LEAF_BASE(result_type, header)
384
385
386 // Close the routine and the extern "C"
387 #define JNI_END } }
388
389
390
391 // Definitions for JVM
392
393 #define JVM_ENTRY(result_type, header) \
394 extern "C" { \
395 result_type JNICALL header { \
396 JavaThread* thread=JavaThread::thread_from_jni_environment(env); \
397 ThreadInVMfromNative __tiv(thread); \
398 MACOS_AARCH64_ONLY( \
399 static WXMode wx_mode = DefaultWXWriteMode; \
400 ThreadWXEnable __wx(&wx_mode, thread); \
401 ) \
402 DEBUG_ONLY(VMNativeEntryWrapper __vew;) \
403 VM_ENTRY_BASE(result_type, header, thread)
404
405
406 #define JVM_ENTRY_NO_ENV(result_type, header) \
407 extern "C" { \
408 result_type JNICALL header { \
409 JavaThread* thread = JavaThread::current(); \
410 ThreadInVMfromNative __tiv(thread); \
411 MACOS_AARCH64_ONLY( \
412 static WXMode wx_mode = DefaultWXWriteMode; \
413 ThreadWXEnable __wx(&wx_mode, thread); \
414 ) \
415 DEBUG_ONLY(VMNativeEntryWrapper __vew;) \
416 VM_ENTRY_BASE(result_type, header, thread)
417
418
419 #define JVM_LEAF(result_type, header) \
420 extern "C" { \
421 result_type JNICALL header { \
422 VM_Exit::block_if_vm_exited(); \
423 VM_LEAF_BASE(result_type, header)
424
425
426 #define JVM_END } }
427
428 #endif // SHARE_RUNTIME_INTERFACESUPPORT_INLINE_HPP