1 /*
2 * Copyright (c) 2000, 2025, 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 "classfile/classFileStream.hpp"
26 #include "classfile/classLoader.hpp"
27 #include "classfile/classLoadInfo.hpp"
28 #include "classfile/javaClasses.inline.hpp"
29 #include "classfile/systemDictionary.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "jfr/jfrEvents.hpp"
32 #include "jni.h"
33 #include "jvm.h"
34 #include "memory/allocation.inline.hpp"
35 #include "memory/oopFactory.hpp"
36 #include "memory/resourceArea.hpp"
37 #include "logging/log.hpp"
38 #include "logging/logStream.hpp"
39 #include "oops/access.inline.hpp"
40 #include "oops/fieldStreams.inline.hpp"
41 #include "oops/flatArrayKlass.hpp"
42 #include "oops/flatArrayOop.inline.hpp"
43 #include "oops/inlineKlass.inline.hpp"
44 #include "oops/instanceKlass.inline.hpp"
45 #include "oops/klass.inline.hpp"
46 #include "oops/objArrayOop.inline.hpp"
47 #include "oops/oop.inline.hpp"
48 #include "oops/typeArrayOop.inline.hpp"
49 #include "prims/jvmtiExport.hpp"
50 #include "prims/unsafe.hpp"
51 #include "runtime/fieldDescriptor.inline.hpp"
52 #include "runtime/globals.hpp"
53 #include "runtime/handles.inline.hpp"
54 #include "runtime/interfaceSupport.inline.hpp"
55 #include "runtime/javaThread.inline.hpp"
56 #include "runtime/jniHandles.inline.hpp"
57 #include "runtime/orderAccess.hpp"
58 #include "runtime/reflection.hpp"
59 #include "runtime/sharedRuntime.hpp"
60 #include "runtime/stubRoutines.hpp"
61 #include "runtime/threadSMR.hpp"
62 #include "runtime/vmOperations.hpp"
63 #include "runtime/vm_version.hpp"
64 #include "sanitizers/ub.hpp"
65 #include "services/threadService.hpp"
66 #include "utilities/align.hpp"
67 #include "utilities/copy.hpp"
68 #include "utilities/dtrace.hpp"
69 #include "utilities/macros.hpp"
70
71 /**
72 * Implementation of the jdk.internal.misc.Unsafe class
73 */
74
75
76 #define MAX_OBJECT_SIZE \
77 ( arrayOopDesc::base_offset_in_bytes(T_DOUBLE) \
78 + ((julong)max_jint * sizeof(double)) )
79
80 #define UNSAFE_ENTRY(result_type, header) \
81 JVM_ENTRY(static result_type, header)
82
83 #define UNSAFE_LEAF(result_type, header) \
84 JVM_LEAF(static result_type, header)
85
86 // All memory access methods (e.g. getInt, copyMemory) must use this macro.
87 // We call these methods "scoped" methods, as access to these methods is
88 // typically governed by a "scope" (a MemorySessionImpl object), and no
89 // access is allowed when the scope is no longer alive.
90 //
91 // Closing a scope object (cf. scopedMemoryAccess.cpp) can install
92 // an async exception during a safepoint. When that happens,
93 // scoped methods are not allowed to touch the underlying memory (as that
94 // memory might have been released). Therefore, when entering a scoped method
95 // we check if an async exception has been installed, and return immediately
96 // if that is the case.
97 //
98 // As a rule, we disallow safepoints in the middle of a scoped method.
99 // If an async exception handshake were installed in such a safepoint,
100 // memory access might still occur before the handshake is honored by
101 // the accessing thread.
102 //
103 // Corollary: as threads in native state are considered to be at a safepoint,
104 // scoped methods must NOT be executed while in the native thread state.
105 // Because of this, there can be no UNSAFE_LEAF_SCOPED.
106 #define UNSAFE_ENTRY_SCOPED(result_type, header) \
107 JVM_ENTRY(static result_type, header) \
108 if (thread->has_async_exception_condition()) {return (result_type)0;}
109
110 #define UNSAFE_END JVM_END
111
112
113 static inline void* addr_from_java(jlong addr) {
114 // This assert fails in a variety of ways on 32-bit systems.
115 // It is impossible to predict whether native code that converts
116 // pointers to longs will sign-extend or zero-extend the addresses.
117 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
118 return (void*)(uintptr_t)addr;
119 }
120
121 static inline jlong addr_to_java(void* p) {
122 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
123 return (uintptr_t)p;
124 }
125
126
127 // Note: The VM's obj_field and related accessors use byte-scaled
128 // ("unscaled") offsets, just as the unsafe methods do.
129
130 // However, the method Unsafe.fieldOffset explicitly declines to
131 // guarantee this. The field offset values manipulated by the Java user
132 // through the Unsafe API are opaque cookies that just happen to be byte
133 // offsets. We represent this state of affairs by passing the cookies
134 // through conversion functions when going between the VM and the Unsafe API.
135 // The conversion functions just happen to be no-ops at present.
136
137 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
138 return field_offset;
139 }
140
141 static inline int field_offset_from_byte_offset(int byte_offset) {
142 return byte_offset;
143 }
144
145 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
146 #ifdef ASSERT
147 jlong byte_offset = field_offset_to_byte_offset(field_offset);
148
149 if (p != nullptr) {
150 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
151 if (byte_offset == (jint)byte_offset) {
152 void* ptr_plus_disp = cast_from_oop<address>(p) + byte_offset;
153 assert(p->field_addr<void>((jint)byte_offset) == ptr_plus_disp,
154 "raw [ptr+disp] must be consistent with oop::field_addr");
155 }
156 jlong p_size = HeapWordSize * (jlong)(p->size());
157 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
158 }
159 #endif
160 }
161
162 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
163 assert_field_offset_sane(p, field_offset);
164 uintptr_t base_address = cast_from_oop<uintptr_t>(p);
165 uintptr_t byte_offset = (uintptr_t)field_offset_to_byte_offset(field_offset);
166 return (void*)(base_address + byte_offset);
167 }
168
169 // Externally callable versions:
170 // (Use these in compiler intrinsics which emulate unsafe primitives.)
171 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
172 return field_offset;
173 }
174 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
175 return byte_offset;
176 }
177
178 ///// Data read/writes on the Java heap and in native (off-heap) memory
179
180 /**
181 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
182 */
183 class GuardUnsafeAccess {
184 JavaThread* _thread;
185
186 public:
187 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
188 // native/off-heap access which may raise SIGBUS if accessing
189 // memory mapped file data in a region of the file which has
190 // been truncated and is now invalid.
191 _thread->set_doing_unsafe_access(true);
192 }
193
194 ~GuardUnsafeAccess() {
195 _thread->set_doing_unsafe_access(false);
196 }
197 };
198
199 /**
200 * Helper class for accessing memory.
201 *
202 * Normalizes values and wraps accesses in
203 * JavaThread::doing_unsafe_access() if needed.
204 */
205 template <typename T>
206 class MemoryAccess : StackObj {
207 JavaThread* _thread;
208 oop _obj;
209 ptrdiff_t _offset;
210
211 // Resolves and returns the address of the memory access.
212 // This raw memory access may fault, so we make sure it happens within the
213 // guarded scope by making the access volatile at least. Since the store
214 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
215 // can not be reordered by the compiler. Therefore, if the access triggers
216 // a fault, we will know that Thread::doing_unsafe_access() returns true.
217 volatile T* addr() {
218 void* addr = index_oop_from_field_offset_long(_obj, _offset);
219 return static_cast<volatile T*>(addr);
220 }
221
222 template <typename U>
223 U normalize_for_write(U x) {
224 return x;
225 }
226
227 jboolean normalize_for_write(jboolean x) {
228 return x & 1;
229 }
230
231 template <typename U>
232 U normalize_for_read(U x) {
233 return x;
234 }
235
236 jboolean normalize_for_read(jboolean x) {
237 return x != 0;
238 }
239
240 public:
241 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
242 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
243 assert_field_offset_sane(_obj, offset);
244 }
245
246 T get() {
247 GuardUnsafeAccess guard(_thread);
248 return normalize_for_read(*addr());
249 }
250
251 // we use this method at some places for writing to 0 e.g. to cause a crash;
252 // ubsan does not know that this is the desired behavior
253 ATTRIBUTE_NO_UBSAN
254 void put(T x) {
255 GuardUnsafeAccess guard(_thread);
256 assert(_obj == nullptr || !_obj->is_inline_type() || _obj->mark().is_larval_state(), "must be an object instance or a larval inline type");
257 *addr() = normalize_for_write(x);
258 }
259
260 T get_volatile() {
261 GuardUnsafeAccess guard(_thread);
262 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
263 return normalize_for_read(ret);
264 }
265
266 void put_volatile(T x) {
267 GuardUnsafeAccess guard(_thread);
268 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
269 }
270 };
271
272 #ifdef ASSERT
273 /*
274 * Get the field descriptor of the field of the given object at the given offset.
275 */
276 static bool get_field_descriptor(oop p, jlong offset, fieldDescriptor* fd) {
277 bool found = false;
278 Klass* k = p->klass();
279 if (k->is_instance_klass()) {
280 InstanceKlass* ik = InstanceKlass::cast(k);
281 found = ik->find_field_from_offset((int)offset, false, fd);
282 if (!found && ik->is_mirror_instance_klass()) {
283 Klass* k2 = java_lang_Class::as_Klass(p);
284 if (k2->is_instance_klass()) {
285 ik = InstanceKlass::cast(k2);
286 found = ik->find_field_from_offset((int)offset, true, fd);
287 }
288 }
289 }
290 return found;
291 }
292 #endif // ASSERT
293
294 static void assert_and_log_unsafe_value_access(oop p, jlong offset, InlineKlass* vk) {
295 Klass* k = p->klass();
296 #ifdef ASSERT
297 if (k->is_instance_klass()) {
298 assert_field_offset_sane(p, offset);
299 fieldDescriptor fd;
300 bool found = get_field_descriptor(p, offset, &fd);
301 if (found) {
302 assert(found, "value field not found");
303 assert(fd.is_flat(), "field not flat");
304 } else {
305 if (log_is_enabled(Trace, valuetypes)) {
306 log_trace(valuetypes)("not a field in %s at offset " UINT64_FORMAT_X,
307 p->klass()->external_name(), (uint64_t)offset);
308 }
309 }
310 } else if (k->is_flatArray_klass()) {
311 FlatArrayKlass* vak = FlatArrayKlass::cast(k);
312 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
313 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper());
314 assert(dest == (cast_from_oop<address>(p) + offset), "invalid offset");
315 } else {
316 ShouldNotReachHere();
317 }
318 #endif // ASSERT
319 if (log_is_enabled(Trace, valuetypes)) {
320 if (k->is_flatArray_klass()) {
321 FlatArrayKlass* vak = FlatArrayKlass::cast(k);
322 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
323 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper());
324 log_trace(valuetypes)("%s array type %s index %d element size %d offset " UINT64_FORMAT_X " at " INTPTR_FORMAT,
325 p->klass()->external_name(), vak->external_name(),
326 index, vak->element_byte_size(), (uint64_t)offset, p2i(dest));
327 } else {
328 log_trace(valuetypes)("%s field type %s at offset " UINT64_FORMAT_X,
329 p->klass()->external_name(), vk->external_name(), (uint64_t)offset);
330 }
331 }
332 }
333
334 // These functions allow a null base pointer with an arbitrary address.
335 // But if the base pointer is non-null, the offset should make some sense.
336 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
337 UNSAFE_ENTRY(jobject, Unsafe_GetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
338 oop p = JNIHandles::resolve(obj);
339 assert_field_offset_sane(p, offset);
340 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
341 return JNIHandles::make_local(THREAD, v);
342 } UNSAFE_END
343
344 UNSAFE_ENTRY(void, Unsafe_PutReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
345 oop x = JNIHandles::resolve(x_h);
346 oop p = JNIHandles::resolve(obj);
347 assert_field_offset_sane(p, offset);
348 assert(!p->is_inline_type() || p->mark().is_larval_state(), "must be an object instance or a larval inline type");
349 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
350 } UNSAFE_END
351
352 UNSAFE_ENTRY(jlong, Unsafe_ValueHeaderSize(JNIEnv *env, jobject unsafe, jclass c)) {
353 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
354 InlineKlass* vk = InlineKlass::cast(k);
355 return vk->payload_offset();
356 } UNSAFE_END
357
358 UNSAFE_ENTRY(jboolean, Unsafe_IsFlatField(JNIEnv *env, jobject unsafe, jobject o)) {
359 oop f = JNIHandles::resolve_non_null(o);
360 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
361 int slot = java_lang_reflect_Field::slot(f);
362 return InstanceKlass::cast(k)->field_is_flat(slot);
363 } UNSAFE_END
364
365 UNSAFE_ENTRY(jboolean, Unsafe_HasNullMarker(JNIEnv *env, jobject unsafe, jobject o)) {
366 oop f = JNIHandles::resolve_non_null(o);
367 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
368 int slot = java_lang_reflect_Field::slot(f);
369 return InstanceKlass::cast(k)->field_has_null_marker(slot);
370 } UNSAFE_END
371
372 UNSAFE_ENTRY(jint, Unsafe_NullMarkerOffset(JNIEnv *env, jobject unsafe, jobject o)) {
373 oop f = JNIHandles::resolve_non_null(o);
374 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
375 int slot = java_lang_reflect_Field::slot(f);
376 return InstanceKlass::cast(k)->null_marker_offset(slot);
377 } UNSAFE_END
378
379 UNSAFE_ENTRY(jint, Unsafe_ArrayLayout(JNIEnv *env, jobject unsafe, jclass c)) {
380 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
381 if (!k->is_flatArray_klass()) {
382 return (jint)LayoutKind::REFERENCE;
383 } else {
384 return (jint)FlatArrayKlass::cast(k)->layout_kind();
385 }
386 } UNSAFE_END
387
388 UNSAFE_ENTRY(jint, Unsafe_FieldLayout(JNIEnv *env, jobject unsafe, jobject field)) {
389 assert(field != nullptr, "field must not be null");
390
391 oop reflected = JNIHandles::resolve_non_null(field);
392 oop mirror = java_lang_reflect_Field::clazz(reflected);
393 Klass* k = java_lang_Class::as_Klass(mirror);
394 int slot = java_lang_reflect_Field::slot(reflected);
395 int modifiers = java_lang_reflect_Field::modifiers(reflected);
396
397 if ((modifiers & JVM_ACC_STATIC) != 0) {
398 return (jint)LayoutKind::REFERENCE; // static fields are never flat
399 } else {
400 InstanceKlass* ik = InstanceKlass::cast(k);
401 if (ik->field_is_flat(slot)) {
402 return (jint)ik->inline_layout_info(slot).kind();
403 } else {
404 return (jint)LayoutKind::REFERENCE;
405 }
406 }
407 } UNSAFE_END
408
409 UNSAFE_ENTRY(jarray, Unsafe_NewSpecialArray(JNIEnv *env, jobject unsafe, jclass elmClass, jint len, jint layoutKind)) {
410 oop mirror = JNIHandles::resolve_non_null(elmClass);
411 Klass* klass = java_lang_Class::as_Klass(mirror);
412 klass->initialize(CHECK_NULL);
413 if (len < 0) {
414 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Array length is negative");
415 }
416 if (klass->is_identity_class()) {
417 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Element class is not a value class");
418 }
419 if (klass->is_abstract()) {
420 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Element class is abstract");
421 }
422 LayoutKind lk = static_cast<LayoutKind>(layoutKind);
423 if (lk <= LayoutKind::REFERENCE || lk >= LayoutKind::UNKNOWN) {
424 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Invalid layout kind");
425 }
426 InlineKlass* vk = InlineKlass::cast(klass);
427 // WARNING: test below will need modifications when flat layouts supported for fields
428 // but not for arrays are introduce (NULLABLE_NON_ATOMIC_FLAT for instance)
429 if (!UseArrayFlattening || !vk->is_layout_supported(lk)) {
430 THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "Layout not supported");
431 }
432 oop array = oopFactory::new_flatArray(vk, len, lk, CHECK_NULL);
433 return (jarray) JNIHandles::make_local(THREAD, array);
434 } UNSAFE_END
435
436 UNSAFE_ENTRY(jboolean, Unsafe_IsFlatArray(JNIEnv *env, jobject unsafe, jclass c)) {
437 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
438 return k->is_flatArray_klass();
439 } UNSAFE_END
440
441 UNSAFE_ENTRY(jobject, Unsafe_GetValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc)) {
442 oop base = JNIHandles::resolve(obj);
443 if (base == nullptr) {
444 THROW_NULL(vmSymbols::java_lang_NullPointerException());
445 }
446 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
447 InlineKlass* vk = InlineKlass::cast(k);
448 assert_and_log_unsafe_value_access(base, offset, vk);
449 LayoutKind lk = LayoutKind::UNKNOWN;
450 if (base->is_array()) {
451 FlatArrayKlass* fak = FlatArrayKlass::cast(base->klass());
452 lk = fak->layout_kind();
453 } else {
454 fieldDescriptor fd;
455 InstanceKlass::cast(base->klass())->find_field_from_offset(offset, false, &fd);
456 lk = fd.field_holder()->inline_layout_info(fd.index()).kind();
457 }
458 Handle base_h(THREAD, base);
459 oop v = vk->read_payload_from_addr(base_h(), offset, lk, CHECK_NULL);
460 return JNIHandles::make_local(THREAD, v);
461 } UNSAFE_END
462
463 UNSAFE_ENTRY(jobject, Unsafe_GetFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc)) {
464 assert(layoutKind != (int)LayoutKind::REFERENCE, "This method handles only flat layouts");
465 oop base = JNIHandles::resolve(obj);
466 if (base == nullptr) {
467 THROW_NULL(vmSymbols::java_lang_NullPointerException());
468 }
469 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
470 InlineKlass* vk = InlineKlass::cast(k);
471 assert_and_log_unsafe_value_access(base, offset, vk);
472 LayoutKind lk = (LayoutKind)layoutKind;
473 Handle base_h(THREAD, base);
474 oop v = vk->read_payload_from_addr(base_h(), offset, lk, CHECK_NULL);
475 return JNIHandles::make_local(THREAD, v);
476 } UNSAFE_END
477
478 UNSAFE_ENTRY(void, Unsafe_PutValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc, jobject value)) {
479 oop base = JNIHandles::resolve(obj);
480 if (base == nullptr) {
481 THROW(vmSymbols::java_lang_NullPointerException());
482 }
483 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
484 InlineKlass* vk = InlineKlass::cast(k);
485 assert(!base->is_inline_type() || base->mark().is_larval_state(), "must be an object instance or a larval inline type");
486 assert_and_log_unsafe_value_access(base, offset, vk);
487 LayoutKind lk = LayoutKind::UNKNOWN;
488 if (base->is_array()) {
489 FlatArrayKlass* fak = FlatArrayKlass::cast(base->klass());
490 lk = fak->layout_kind();
491 } else {
492 fieldDescriptor fd;
493 InstanceKlass::cast(base->klass())->find_field_from_offset(offset, false, &fd);
494 lk = fd.field_holder()->inline_layout_info(fd.index()).kind();
495 }
496 oop v = JNIHandles::resolve(value);
497 vk->write_value_to_addr(v, ((char*)(oopDesc*)base) + offset, lk, true, CHECK);
498 } UNSAFE_END
499
500 UNSAFE_ENTRY(void, Unsafe_PutFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc, jobject value)) {
501 assert(layoutKind != (int)LayoutKind::REFERENCE, "This method handles only flat layouts");
502 oop base = JNIHandles::resolve(obj);
503 if (base == nullptr) {
504 THROW(vmSymbols::java_lang_NullPointerException());
505 }
506 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
507 InlineKlass* vk = InlineKlass::cast(k);
508 assert(!base->is_inline_type() || base->mark().is_larval_state(), "must be an object instance or a larval inline type");
509 assert_and_log_unsafe_value_access(base, offset, vk);
510 LayoutKind lk = (LayoutKind)layoutKind;
511 oop v = JNIHandles::resolve(value);
512 vk->write_value_to_addr(v, ((char*)(oopDesc*)base) + offset, lk, true, CHECK);
513 } UNSAFE_END
514
515 UNSAFE_ENTRY(jobject, Unsafe_MakePrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) {
516 oop v = JNIHandles::resolve_non_null(value);
517 assert(v->is_inline_type(), "must be an inline type instance");
518 Handle vh(THREAD, v);
519 InlineKlass* vk = InlineKlass::cast(v->klass());
520 instanceOop new_value = vk->allocate_instance_buffer(CHECK_NULL);
521 vk->copy_payload_to_addr(vk->payload_addr(vh()), vk->payload_addr(new_value), LayoutKind::BUFFERED, false);
522 markWord mark = new_value->mark();
523 new_value->set_mark(mark.enter_larval_state());
524 return JNIHandles::make_local(THREAD, new_value);
525 } UNSAFE_END
526
527 UNSAFE_ENTRY(jobject, Unsafe_FinishPrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) {
528 oop v = JNIHandles::resolve(value);
529 assert(v->mark().is_larval_state(), "must be a larval value");
530 markWord mark = v->mark();
531 v->set_mark(mark.exit_larval_state());
532 return JNIHandles::make_local(THREAD, v);
533 } UNSAFE_END
534
535 UNSAFE_ENTRY(jobject, Unsafe_GetReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
536 oop p = JNIHandles::resolve(obj);
537 assert_field_offset_sane(p, offset);
538 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
539 return JNIHandles::make_local(THREAD, v);
540 } UNSAFE_END
541
542 UNSAFE_ENTRY(void, Unsafe_PutReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
543 oop x = JNIHandles::resolve(x_h);
544 oop p = JNIHandles::resolve(obj);
545 assert_field_offset_sane(p, offset);
546 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
547 } UNSAFE_END
548
549 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
550 oop v = *(oop*) (address) addr;
551 return JNIHandles::make_local(THREAD, v);
552 } UNSAFE_END
553
554 #define DEFINE_GETSETOOP(java_type, Type) \
555 \
556 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
557 return MemoryAccess<java_type>(thread, obj, offset).get(); \
558 } UNSAFE_END \
559 \
560 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
561 MemoryAccess<java_type>(thread, obj, offset).put(x); \
562 } UNSAFE_END \
563 \
564 // END DEFINE_GETSETOOP.
565
566 DEFINE_GETSETOOP(jboolean, Boolean)
567 DEFINE_GETSETOOP(jbyte, Byte)
568 DEFINE_GETSETOOP(jshort, Short);
569 DEFINE_GETSETOOP(jchar, Char);
570 DEFINE_GETSETOOP(jint, Int);
571 DEFINE_GETSETOOP(jlong, Long);
572 DEFINE_GETSETOOP(jfloat, Float);
573 DEFINE_GETSETOOP(jdouble, Double);
574
575 #undef DEFINE_GETSETOOP
576
577 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
578 \
579 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
580 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
581 } UNSAFE_END \
582 \
583 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
584 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
585 } UNSAFE_END \
586 \
587 // END DEFINE_GETSETOOP_VOLATILE.
588
589 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
590 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
591 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
592 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
593 DEFINE_GETSETOOP_VOLATILE(jint, Int);
594 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
595 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
596 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
597
598 #undef DEFINE_GETSETOOP_VOLATILE
599
600 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
601 OrderAccess::fence();
602 } UNSAFE_END
603
604 ////// Allocation requests
605
606 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
607 JvmtiVMObjectAllocEventCollector oam;
608 instanceOop i = InstanceKlass::allocate_instance(JNIHandles::resolve_non_null(cls), CHECK_NULL);
609 return JNIHandles::make_local(THREAD, i);
610 } UNSAFE_END
611
612 UNSAFE_LEAF(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
613 size_t sz = (size_t)size;
614
615 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
616
617 void* x = os::malloc(sz, mtOther);
618
619 return addr_to_java(x);
620 } UNSAFE_END
621
622 UNSAFE_LEAF(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
623 void* p = addr_from_java(addr);
624 size_t sz = (size_t)size;
625
626 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
627
628 void* x = os::realloc(p, sz, mtOther);
629
630 return addr_to_java(x);
631 } UNSAFE_END
632
633 UNSAFE_LEAF(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
634 void* p = addr_from_java(addr);
635
636 os::free(p);
637 } UNSAFE_END
638
639 UNSAFE_ENTRY_SCOPED(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
640 size_t sz = (size_t)size;
641
642 oop base = JNIHandles::resolve(obj);
643 void* p = index_oop_from_field_offset_long(base, offset);
644
645 {
646 GuardUnsafeAccess guard(thread);
647 if (StubRoutines::unsafe_setmemory() != nullptr) {
648 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread));
649 StubRoutines::UnsafeSetMemory_stub()(p, sz, value);
650 } else {
651 Copy::fill_to_memory_atomic(p, sz, value);
652 }
653 }
654 } UNSAFE_END
655
656 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
657 size_t sz = (size_t)size;
658
659 oop srcp = JNIHandles::resolve(srcObj);
660 oop dstp = JNIHandles::resolve(dstObj);
661
662 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
663 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
664 {
665 GuardUnsafeAccess guard(thread);
666 if (StubRoutines::unsafe_arraycopy() != nullptr) {
667 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread));
668 StubRoutines::UnsafeArrayCopy_stub()(src, dst, sz);
669 } else {
670 Copy::conjoint_memory_atomic(src, dst, sz);
671 }
672 }
673 } UNSAFE_END
674
675 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
676 size_t sz = (size_t)size;
677 size_t esz = (size_t)elemSize;
678
679 oop srcp = JNIHandles::resolve(srcObj);
680 oop dstp = JNIHandles::resolve(dstObj);
681
682 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
683 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
684
685 {
686 GuardUnsafeAccess guard(thread);
687 Copy::conjoint_swap(src, dst, sz, esz);
688 }
689 } UNSAFE_END
690
691 UNSAFE_LEAF (void, Unsafe_WriteBack0(JNIEnv *env, jobject unsafe, jlong line)) {
692 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
693 #ifdef ASSERT
694 if (TraceMemoryWriteback) {
695 tty->print_cr("Unsafe: writeback 0x%p", addr_from_java(line));
696 }
697 #endif
698
699 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current()));
700 assert(StubRoutines::data_cache_writeback() != nullptr, "sanity");
701 (StubRoutines::DataCacheWriteback_stub())(addr_from_java(line));
702 } UNSAFE_END
703
704 static void doWriteBackSync0(bool is_pre)
705 {
706 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current()));
707 assert(StubRoutines::data_cache_writeback_sync() != nullptr, "sanity");
708 (StubRoutines::DataCacheWritebackSync_stub())(is_pre);
709 }
710
711 UNSAFE_LEAF (void, Unsafe_WriteBackPreSync0(JNIEnv *env, jobject unsafe)) {
712 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
713 #ifdef ASSERT
714 if (TraceMemoryWriteback) {
715 tty->print_cr("Unsafe: writeback pre-sync");
716 }
717 #endif
718
719 doWriteBackSync0(true);
720 } UNSAFE_END
721
722 UNSAFE_LEAF (void, Unsafe_WriteBackPostSync0(JNIEnv *env, jobject unsafe)) {
723 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
724 #ifdef ASSERT
725 if (TraceMemoryWriteback) {
726 tty->print_cr("Unsafe: writeback pre-sync");
727 }
728 #endif
729
730 doWriteBackSync0(false);
731 } UNSAFE_END
732
733 ////// Random queries
734
735 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
736 assert(clazz != nullptr, "clazz must not be null");
737 assert(name != nullptr, "name must not be null");
738
739 ResourceMark rm(THREAD);
740 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
741
742 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
743
744 jint offset = -1;
745 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
746 Symbol *name = fs.name();
747 if (name->equals(utf_name)) {
748 offset = fs.offset();
749 break;
750 }
751 }
752 if (offset < 0) {
753 THROW_0(vmSymbols::java_lang_InternalError());
754 }
755 return field_offset_from_byte_offset(offset);
756 }
757
758 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
759 assert(field != nullptr, "field must not be null");
760
761 oop reflected = JNIHandles::resolve_non_null(field);
762 oop mirror = java_lang_reflect_Field::clazz(reflected);
763 Klass* k = java_lang_Class::as_Klass(mirror);
764 int slot = java_lang_reflect_Field::slot(reflected);
765 int modifiers = java_lang_reflect_Field::modifiers(reflected);
766
767 if (must_be_static >= 0) {
768 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
769 if (must_be_static != really_is_static) {
770 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
771 }
772 }
773
774 int offset = InstanceKlass::cast(k)->field_offset(slot);
775 return field_offset_from_byte_offset(offset);
776 }
777
778 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
779 return find_field_offset(field, 0, THREAD);
780 } UNSAFE_END
781
782 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
783 return find_field_offset(c, name, THREAD);
784 } UNSAFE_END
785
786 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
787 return find_field_offset(field, 1, THREAD);
788 } UNSAFE_END
789
790 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
791 assert(field != nullptr, "field must not be null");
792
793 // Note: In this VM implementation, a field address is always a short
794 // offset from the base of a klass metaobject. Thus, the full dynamic
795 // range of the return type is never used. However, some implementations
796 // might put the static field inside an array shared by many classes,
797 // or even at a fixed address, in which case the address could be quite
798 // large. In that last case, this function would return null, since
799 // the address would operate alone, without any base pointer.
800
801 oop reflected = JNIHandles::resolve_non_null(field);
802 oop mirror = java_lang_reflect_Field::clazz(reflected);
803 int modifiers = java_lang_reflect_Field::modifiers(reflected);
804
805 if ((modifiers & JVM_ACC_STATIC) == 0) {
806 THROW_NULL(vmSymbols::java_lang_IllegalArgumentException());
807 }
808
809 return JNIHandles::make_local(THREAD, mirror);
810 } UNSAFE_END
811
812 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
813 assert(clazz != nullptr, "clazz must not be null");
814
815 oop mirror = JNIHandles::resolve_non_null(clazz);
816
817 Klass* klass = java_lang_Class::as_Klass(mirror);
818 if (klass != nullptr && klass->should_be_initialized()) {
819 InstanceKlass* k = InstanceKlass::cast(klass);
820 k->initialize(CHECK);
821 }
822 }
823 UNSAFE_END
824
825 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
826 assert(clazz != nullptr, "clazz must not be null");
827
828 oop mirror = JNIHandles::resolve_non_null(clazz);
829 Klass* klass = java_lang_Class::as_Klass(mirror);
830
831 if (klass != nullptr && klass->should_be_initialized()) {
832 return true;
833 }
834
835 return false;
836 }
837 UNSAFE_END
838
839 UNSAFE_ENTRY(void, Unsafe_NotifyStrictStaticAccess0(JNIEnv *env, jobject unsafe, jobject clazz,
840 jlong sfoffset, jboolean writing)) {
841 assert(clazz != nullptr, "clazz must not be null");
842
843 oop mirror = JNIHandles::resolve_non_null(clazz);
844 Klass* klass = java_lang_Class::as_Klass(mirror);
845
846 if (klass != nullptr && klass->is_instance_klass()) {
847 InstanceKlass* ik = InstanceKlass::cast(klass);
848 fieldDescriptor fd;
849 if (ik->find_local_field_from_offset((int)sfoffset, true, &fd)) {
850 // Note: The Unsafe API takes an OFFSET, but the InstanceKlass wants the INDEX.
851 // We could surface field indexes into Unsafe, but that's too much churn.
852 ik->notify_strict_static_access(fd.index(), writing, CHECK);
853 return;
854 }
855 }
856 THROW(vmSymbols::java_lang_InternalError());
857 }
858 UNSAFE_END
859
860 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
861 assert(clazz != nullptr, "clazz must not be null");
862
863 oop mirror = JNIHandles::resolve_non_null(clazz);
864 Klass* k = java_lang_Class::as_Klass(mirror);
865
866 if (k == nullptr || !k->is_array_klass()) {
867 THROW(vmSymbols::java_lang_InvalidClassException());
868 } else if (k->is_objArray_klass()) {
869 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
870 scale = heapOopSize;
871 } else if (k->is_typeArray_klass()) {
872 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
873 base = tak->array_header_in_bytes();
874 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
875 scale = (1 << tak->log2_element_size());
876 } else if (k->is_flatArray_klass()) {
877 FlatArrayKlass* vak = FlatArrayKlass::cast(k);
878 InlineKlass* vklass = vak->element_klass();
879 base = vak->array_header_in_bytes();
880 scale = vak->element_byte_size();
881 } else {
882 ShouldNotReachHere();
883 }
884 }
885
886 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
887 int base = 0, scale = 0;
888 getBaseAndScale(base, scale, clazz, CHECK_0);
889
890 return field_offset_from_byte_offset(base);
891 } UNSAFE_END
892
893
894 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
895 int base = 0, scale = 0;
896 getBaseAndScale(base, scale, clazz, CHECK_0);
897
898 // This VM packs both fields and array elements down to the byte.
899 // But watch out: If this changes, so that array references for
900 // a given primitive type (say, T_BOOLEAN) use different memory units
901 // than fields, this method MUST return zero for such arrays.
902 // For example, the VM used to store sub-word sized fields in full
903 // words in the object layout, so that accessors like getByte(Object,int)
904 // did not really do what one might expect for arrays. Therefore,
905 // this function used to report a zero scale factor, so that the user
906 // would know not to attempt to access sub-word array elements.
907 // // Code for unpacked fields:
908 // if (scale < wordSize) return 0;
909
910 // The following allows for a pretty general fieldOffset cookie scheme,
911 // but requires it to be linear in byte offset.
912 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
913 } UNSAFE_END
914
915
916 UNSAFE_ENTRY(jlong, Unsafe_GetObjectSize0(JNIEnv* env, jobject o, jobject obj))
917 oop p = JNIHandles::resolve(obj);
918 return p->size() * HeapWordSize;
919 UNSAFE_END
920
921
922 static inline void throw_new(JNIEnv *env, const char *ename) {
923 jclass cls = env->FindClass(ename);
924 if (env->ExceptionCheck()) {
925 env->ExceptionClear();
926 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
927 return;
928 }
929
930 env->ThrowNew(cls, nullptr);
931 }
932
933 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
934 // Code lifted from JDK 1.3 ClassLoader.c
935
936 jbyte *body;
937 char *utfName = nullptr;
938 jclass result = nullptr;
939 char buf[128];
940
941 assert(data != nullptr, "Class bytes must not be null");
942 assert(length >= 0, "length must not be negative: %d", length);
943
944 if (UsePerfData) {
945 ClassLoader::unsafe_defineClassCallCounter()->inc();
946 }
947
948 body = NEW_C_HEAP_ARRAY_RETURN_NULL(jbyte, length, mtInternal);
949 if (body == nullptr) {
950 throw_new(env, "java/lang/OutOfMemoryError");
951 return nullptr;
952 }
953
954 env->GetByteArrayRegion(data, offset, length, body);
955 if (env->ExceptionCheck()) {
956 goto free_body;
957 }
958
959 if (name != nullptr) {
960 uint len = env->GetStringUTFLength(name);
961 int unicode_len = env->GetStringLength(name);
962
963 if (len >= sizeof(buf)) {
964 utfName = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len + 1, mtInternal);
965 if (utfName == nullptr) {
966 throw_new(env, "java/lang/OutOfMemoryError");
967 goto free_body;
968 }
969 } else {
970 utfName = buf;
971 }
972
973 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
974
975 for (uint i = 0; i < len; i++) {
976 if (utfName[i] == '.') utfName[i] = '/';
977 }
978 }
979
980 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
981
982 if (utfName && utfName != buf) {
983 FREE_C_HEAP_ARRAY(char, utfName);
984 }
985
986 free_body:
987 FREE_C_HEAP_ARRAY(jbyte, body);
988 return result;
989 }
990
991
992 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
993 ThreadToNativeFromVM ttnfv(thread);
994
995 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
996 } UNSAFE_END
997
998
999 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
1000 ThreadToNativeFromVM ttnfv(thread);
1001 env->Throw(thr);
1002 } UNSAFE_END
1003
1004 // JSR166 ------------------------------------------------------------------
1005
1006 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1007 oop x = JNIHandles::resolve(x_h);
1008 oop e = JNIHandles::resolve(e_h);
1009 oop p = JNIHandles::resolve(obj);
1010 assert_field_offset_sane(p, offset);
1011 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
1012 return JNIHandles::make_local(THREAD, res);
1013 } UNSAFE_END
1014
1015 UNSAFE_ENTRY_SCOPED(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1016 oop p = JNIHandles::resolve(obj);
1017 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1018 return Atomic::cmpxchg(addr, e, x);
1019 } UNSAFE_END
1020
1021 UNSAFE_ENTRY_SCOPED(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1022 oop p = JNIHandles::resolve(obj);
1023 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1024 return Atomic::cmpxchg(addr, e, x);
1025 } UNSAFE_END
1026
1027 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1028 oop x = JNIHandles::resolve(x_h);
1029 oop e = JNIHandles::resolve(e_h);
1030 oop p = JNIHandles::resolve(obj);
1031 assert_field_offset_sane(p, offset);
1032 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
1033 return ret == e;
1034 } UNSAFE_END
1035
1036 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1037 oop p = JNIHandles::resolve(obj);
1038 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1039 return Atomic::cmpxchg(addr, e, x) == e;
1040 } UNSAFE_END
1041
1042 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1043 oop p = JNIHandles::resolve(obj);
1044 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1045 return Atomic::cmpxchg(addr, e, x) == e;
1046 } UNSAFE_END
1047
1048 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) {
1049 assert(event != nullptr, "invariant");
1050 event->set_parkedClass((obj != nullptr) ? obj->klass() : nullptr);
1051 event->set_timeout(timeout_nanos);
1052 event->set_until(until_epoch_millis);
1053 event->set_address((obj != nullptr) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1054 event->commit();
1055 }
1056
1057 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1058 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1059 EventThreadPark event;
1060
1061 JavaThreadParkedState jtps(thread, time != 0);
1062 thread->parker()->park(isAbsolute != 0, time);
1063 if (event.should_commit()) {
1064 const oop obj = thread->current_park_blocker();
1065 if (time == 0) {
1066 post_thread_park_event(&event, obj, min_jlong, min_jlong);
1067 } else {
1068 if (isAbsolute != 0) {
1069 post_thread_park_event(&event, obj, min_jlong, time);
1070 } else {
1071 post_thread_park_event(&event, obj, time, min_jlong);
1072 }
1073 }
1074 }
1075 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1076 } UNSAFE_END
1077
1078 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1079 if (jthread != nullptr) {
1080 oop thread_oop = JNIHandles::resolve_non_null(jthread);
1081 // Get the JavaThread* stored in the java.lang.Thread object _before_
1082 // the embedded ThreadsListHandle is constructed so we know if the
1083 // early life stage of the JavaThread* is protected. We use acquire
1084 // here to ensure that if we see a non-nullptr value, then we also
1085 // see the main ThreadsList updates from the JavaThread* being added.
1086 FastThreadsListHandle ftlh(thread_oop, java_lang_Thread::thread_acquire(thread_oop));
1087 JavaThread* thr = ftlh.protected_java_thread();
1088 if (thr != nullptr) {
1089 // The still live JavaThread* is protected by the FastThreadsListHandle
1090 // so it is safe to access.
1091 Parker* p = thr->parker();
1092 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1093 p->unpark();
1094 }
1095 } // FastThreadsListHandle is destroyed here.
1096 } UNSAFE_END
1097
1098 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1099 const int max_nelem = 3;
1100 double la[max_nelem];
1101 jint ret;
1102
1103 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1104 assert(a->is_typeArray(), "must be type array");
1105
1106 ret = os::loadavg(la, nelem);
1107 if (ret == -1) {
1108 return -1;
1109 }
1110
1111 // if successful, ret is the number of samples actually retrieved.
1112 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1113 switch(ret) {
1114 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1115 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1116 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1117 }
1118
1119 return ret;
1120 } UNSAFE_END
1121
1122
1123 /// JVM_RegisterUnsafeMethods
1124
1125 #define ADR "J"
1126
1127 #define LANG "Ljava/lang/"
1128
1129 #define OBJ LANG "Object;"
1130 #define CLS LANG "Class;"
1131 #define FLD LANG "reflect/Field;"
1132 #define THR LANG "Throwable;"
1133
1134 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1135 #define DAC_Args CLS "[B[" OBJ
1136
1137 #define CC (char*) /*cast a literal from (const char*)*/
1138 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1139
1140 #define DECLARE_GETPUTOOP(Type, Desc) \
1141 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1142 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1143 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1144 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1145
1146
1147 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1148 {CC "getReference", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetReference)},
1149 {CC "putReference", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReference)},
1150 {CC "getReferenceVolatile", CC "(" OBJ "J)" OBJ, FN_PTR(Unsafe_GetReferenceVolatile)},
1151 {CC "putReferenceVolatile", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReferenceVolatile)},
1152
1153 {CC "isFlatArray", CC "(" CLS ")Z", FN_PTR(Unsafe_IsFlatArray)},
1154 {CC "isFlatField0", CC "(" OBJ ")Z", FN_PTR(Unsafe_IsFlatField)},
1155 {CC "hasNullMarker0", CC "(" OBJ ")Z", FN_PTR(Unsafe_HasNullMarker)},
1156 {CC "nullMarkerOffset0", CC "(" OBJ ")I", FN_PTR(Unsafe_NullMarkerOffset)},
1157 {CC "arrayLayout0", CC "(" OBJ ")I", FN_PTR(Unsafe_ArrayLayout)},
1158 {CC "fieldLayout0", CC "(" OBJ ")I", FN_PTR(Unsafe_FieldLayout)},
1159 {CC "newSpecialArray", CC "(" CLS "II)[" OBJ, FN_PTR(Unsafe_NewSpecialArray)},
1160 {CC "getValue", CC "(" OBJ "J" CLS ")" OBJ, FN_PTR(Unsafe_GetValue)},
1161 {CC "getFlatValue", CC "(" OBJ "JI" CLS ")" OBJ, FN_PTR(Unsafe_GetFlatValue)},
1162 {CC "putValue", CC "(" OBJ "J" CLS OBJ ")V", FN_PTR(Unsafe_PutValue)},
1163 {CC "putFlatValue", CC "(" OBJ "JI" CLS OBJ ")V", FN_PTR(Unsafe_PutFlatValue)},
1164 {CC "makePrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_MakePrivateBuffer)},
1165 {CC "finishPrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_FinishPrivateBuffer)},
1166 {CC "valueHeaderSize", CC "(" CLS ")J", FN_PTR(Unsafe_ValueHeaderSize)},
1167
1168 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1169
1170 DECLARE_GETPUTOOP(Boolean, Z),
1171 DECLARE_GETPUTOOP(Byte, B),
1172 DECLARE_GETPUTOOP(Short, S),
1173 DECLARE_GETPUTOOP(Char, C),
1174 DECLARE_GETPUTOOP(Int, I),
1175 DECLARE_GETPUTOOP(Long, J),
1176 DECLARE_GETPUTOOP(Float, F),
1177 DECLARE_GETPUTOOP(Double, D),
1178
1179 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1180 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1181 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1182
1183 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1184 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1185 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1186 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1187 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1188 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1189 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1190 {CC "getObjectSize0", CC "(Ljava/lang/Object;)J", FN_PTR(Unsafe_GetObjectSize0)},
1191
1192 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1193 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1194 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1195 {CC "compareAndSetReference",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetReference)},
1196 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1197 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1198 {CC "compareAndExchangeReference", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeReference)},
1199 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1200 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1201
1202 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1203 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1204
1205 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1206
1207 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1208 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1209 {CC "writeback0", CC "(" "J" ")V", FN_PTR(Unsafe_WriteBack0)},
1210 {CC "writebackPreSync0", CC "()V", FN_PTR(Unsafe_WriteBackPreSync0)},
1211 {CC "writebackPostSync0", CC "()V", FN_PTR(Unsafe_WriteBackPostSync0)},
1212 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1213
1214 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1215 {CC "notifyStrictStaticAccess0", CC "(" CLS "JZ)V", FN_PTR(Unsafe_NotifyStrictStaticAccess0)},
1216
1217 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1218 };
1219
1220 #undef CC
1221 #undef FN_PTR
1222
1223 #undef ADR
1224 #undef LANG
1225 #undef OBJ
1226 #undef CLS
1227 #undef FLD
1228 #undef THR
1229 #undef DC_Args
1230 #undef DAC_Args
1231
1232 #undef DECLARE_GETPUTOOP
1233
1234
1235 // This function is exported, used by NativeLookup.
1236 // The Unsafe_xxx functions above are called only from the interpreter.
1237 // The optimizer looks at names and signatures to recognize
1238 // individual functions.
1239
1240 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1241 ThreadToNativeFromVM ttnfv(thread);
1242
1243 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1244 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1245 } JVM_END