1 /*
2 * Copyright (c) 2000, 2026, 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 "logging/log.hpp"
35 #include "logging/logStream.hpp"
36 #include "memory/allocation.inline.hpp"
37 #include "memory/oopFactory.hpp"
38 #include "memory/resourceArea.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/oopCast.inline.hpp"
49 #include "oops/typeArrayOop.inline.hpp"
50 #include "oops/valuePayload.hpp"
51 #include "prims/jvmtiExport.hpp"
52 #include "prims/unsafe.hpp"
53 #include "runtime/fieldDescriptor.inline.hpp"
54 #include "runtime/globals.hpp"
55 #include "runtime/handles.inline.hpp"
56 #include "runtime/interfaceSupport.inline.hpp"
57 #include "runtime/javaThread.inline.hpp"
58 #include "runtime/jniHandles.inline.hpp"
59 #include "runtime/orderAccess.hpp"
60 #include "runtime/reflection.hpp"
61 #include "runtime/sharedRuntime.hpp"
62 #include "runtime/stubRoutines.hpp"
63 #include "runtime/threadSMR.hpp"
64 #include "runtime/vm_version.hpp"
65 #include "runtime/vmOperations.hpp"
66 #include "sanitizers/ub.hpp"
67 #include "services/threadService.hpp"
68 #include "utilities/align.hpp"
69 #include "utilities/copy.hpp"
70 #include "utilities/dtrace.hpp"
71 #include "utilities/macros.hpp"
72
73 /**
74 * Implementation of the jdk.internal.misc.Unsafe class
75 */
76
77
78 #define MAX_OBJECT_SIZE \
79 ( arrayOopDesc::base_offset_in_bytes(T_DOUBLE) \
80 + ((julong)max_jint * sizeof(double)) )
81
82 #define UNSAFE_ENTRY(result_type, header) \
83 JVM_ENTRY(static result_type, header)
84
85 #define UNSAFE_LEAF(result_type, header) \
86 JVM_LEAF(static result_type, header)
87
88 // All memory access methods (e.g. getInt, copyMemory) must use this macro.
89 // We call these methods "scoped" methods, as access to these methods is
90 // typically governed by a "scope" (a MemorySessionImpl object), and no
91 // access is allowed when the scope is no longer alive.
92 //
93 // Closing a scope object (cf. scopedMemoryAccess.cpp) can install
94 // an async exception during a safepoint. When that happens,
95 // scoped methods are not allowed to touch the underlying memory (as that
96 // memory might have been released). Therefore, when entering a scoped method
97 // we check if an async exception has been installed, and return immediately
98 // if that is the case.
99 //
100 // As a rule, we disallow safepoints in the middle of a scoped method.
101 // If an async exception handshake were installed in such a safepoint,
102 // memory access might still occur before the handshake is honored by
103 // the accessing thread.
104 //
105 // Corollary: as threads in native state are considered to be at a safepoint,
106 // scoped methods must NOT be executed while in the native thread state.
107 // Because of this, there can be no UNSAFE_LEAF_SCOPED.
108 #define UNSAFE_ENTRY_SCOPED(result_type, header) \
109 JVM_ENTRY(static result_type, header) \
110 if (thread->has_async_exception_condition()) {return (result_type)0;}
111
112 #define UNSAFE_END JVM_END
113
114
115 static inline void* addr_from_java(jlong addr) {
116 // This assert fails in a variety of ways on 32-bit systems.
117 // It is impossible to predict whether native code that converts
118 // pointers to longs will sign-extend or zero-extend the addresses.
119 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
120 return (void*)(uintptr_t)addr;
121 }
122
123 static inline jlong addr_to_java(void* p) {
124 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
125 return (uintptr_t)p;
126 }
127
128
129 // Note: The VM's obj_field and related accessors use byte-scaled
130 // ("unscaled") offsets, just as the unsafe methods do.
131
132 // However, the method Unsafe.fieldOffset explicitly declines to
133 // guarantee this. The field offset values manipulated by the Java user
134 // through the Unsafe API are opaque cookies that just happen to be byte
135 // offsets. We represent this state of affairs by passing the cookies
136 // through conversion functions when going between the VM and the Unsafe API.
137 // The conversion functions just happen to be no-ops at present.
138
139 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
140 return field_offset;
141 }
142
143 static inline int field_offset_from_byte_offset(int byte_offset) {
144 return byte_offset;
145 }
146
147 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
148 #ifdef ASSERT
149 jlong byte_offset = field_offset_to_byte_offset(field_offset);
150
151 if (p != nullptr) {
152 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
153 if (byte_offset == (jint)byte_offset) {
154 void* ptr_plus_disp = cast_from_oop<address>(p) + byte_offset;
155 assert(p->field_addr<void>((jint)byte_offset) == ptr_plus_disp,
156 "raw [ptr+disp] must be consistent with oop::field_addr");
157 }
158 jlong p_size = HeapWordSize * (jlong)(p->size());
159 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
160 }
161 #endif
162 }
163
164 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
165 assert_field_offset_sane(p, field_offset);
166 uintptr_t base_address = cast_from_oop<uintptr_t>(p);
167 uintptr_t byte_offset = (uintptr_t)field_offset_to_byte_offset(field_offset);
168 return (void*)(base_address + byte_offset);
169 }
170
171 // Externally callable versions:
172 // (Use these in compiler intrinsics which emulate unsafe primitives.)
173 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
174 return field_offset;
175 }
176 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
177 return byte_offset;
178 }
179
180
181 ///// Data read/writes on the Java heap and in native (off-heap) memory
182
183 /**
184 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
185 */
186 class GuardUnsafeAccess {
187 JavaThread* _thread;
188
189 public:
190 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
191 // native/off-heap access which may raise SIGBUS if accessing
192 // memory mapped file data in a region of the file which has
193 // been truncated and is now invalid.
194 _thread->set_doing_unsafe_access(true);
195 }
196
197 ~GuardUnsafeAccess() {
198 _thread->set_doing_unsafe_access(false);
199 }
200 };
201
202 /**
203 * Helper class for accessing memory.
204 *
205 * Normalizes values and wraps accesses in
206 * JavaThread::doing_unsafe_access() if needed.
207 */
208 template <typename T>
209 class MemoryAccess : StackObj {
210 JavaThread* _thread;
211 oop _obj;
212 ptrdiff_t _offset;
213
214 // Resolves and returns the address of the memory access.
215 // This raw memory access may fault, so we make sure it happens within the
216 // guarded scope by making the access volatile at least. Since the store
217 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
218 // can not be reordered by the compiler. Therefore, if the access triggers
219 // a fault, we will know that Thread::doing_unsafe_access() returns true.
220 volatile T* addr() {
221 void* addr = index_oop_from_field_offset_long(_obj, _offset);
222 return static_cast<volatile T*>(addr);
223 }
224
225 template <typename U>
226 U normalize_for_write(U x) {
227 return x;
228 }
229
230 jboolean normalize_for_write(jboolean x) {
231 return x & 1;
232 }
233
234 template <typename U>
235 U normalize_for_read(U x) {
236 return x;
237 }
238
239 jboolean normalize_for_read(jboolean x) {
240 return x != 0;
241 }
242
243 public:
244 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
245 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
246 assert_field_offset_sane(_obj, offset);
247 }
248
249 T get() {
250 GuardUnsafeAccess guard(_thread);
251 return normalize_for_read(*addr());
252 }
253
254 // we use this method at some places for writing to 0 e.g. to cause a crash;
255 // ubsan does not know that this is the desired behavior
256 ATTRIBUTE_NO_UBSAN
257 void put(T x) {
258 GuardUnsafeAccess guard(_thread);
259 assert(_obj == nullptr || !_obj->is_inline_type(), "receiver cannot be an instance of a value class because they are immutable");
260 *addr() = normalize_for_write(x);
261 }
262
263
264 T get_volatile() {
265 GuardUnsafeAccess guard(_thread);
266 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
267 return normalize_for_read(ret);
268 }
269
270 void put_volatile(T x) {
271 GuardUnsafeAccess guard(_thread);
272 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
273 }
274 };
275
276 static void log_unsafe_value_access(oop p, jlong offset, InlineKlass* vk) {
277 Klass* k = p->klass();
278 if (log_is_enabled(Trace, valuetypes)) {
279 ResourceMark rm;
280 if (k->is_flatArray_klass()) {
281 FlatArrayKlass* vak = FlatArrayKlass::cast(k);
282 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
283 flatArrayOop array = oop_cast<flatArrayOop>(p);
284 if (index >= 0 && index < array->length()) {
285 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper());
286 log_trace(valuetypes)("%s array type %s index %d element size %d offset " UINT64_FORMAT_X " at " INTPTR_FORMAT,
287 p->klass()->external_name(), vak->external_name(),
288 index, vak->element_byte_size(), (uint64_t)offset, p2i(dest));
289 } else {
290 log_trace(valuetypes)("%s array type %s out-of-bounds index %d element size %d offset " UINT64_FORMAT_X,
291 p->klass()->external_name(), vak->external_name(), index, vak->element_byte_size(), (uint64_t)offset);
292 }
293 } else {
294 log_trace(valuetypes)("%s field type %s at offset " UINT64_FORMAT_X,
295 p->klass()->external_name(), vk->external_name(), (uint64_t)offset);
296 }
297 }
298 }
299
300 // These functions allow a null base pointer with an arbitrary address.
301 // But if the base pointer is non-null, the offset should make some sense.
302 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
303 UNSAFE_ENTRY(jobject, Unsafe_GetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
304 oop p = JNIHandles::resolve(obj);
305 assert_field_offset_sane(p, offset);
306 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
307 return JNIHandles::make_local(THREAD, v);
308 } UNSAFE_END
309
310 UNSAFE_ENTRY(void, Unsafe_PutReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
311 oop x = JNIHandles::resolve(x_h);
312 oop p = JNIHandles::resolve(obj);
313 assert_field_offset_sane(p, offset);
314 assert(!p->is_inline_type(), "receiver cannot be an instance of a value class because they are immutable");
315 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
316 } UNSAFE_END
317
318 UNSAFE_ENTRY(jlong, Unsafe_ValueHeaderSize(JNIEnv *env, jobject unsafe, jclass c)) {
319 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
320 InlineKlass* vk = InlineKlass::cast(k);
321 return vk->payload_offset();
322 } UNSAFE_END
323
324 UNSAFE_ENTRY(jboolean, Unsafe_IsFlatField(JNIEnv *env, jobject unsafe, jobject o)) {
325 oop f = JNIHandles::resolve_non_null(o);
326 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
327 int slot = java_lang_reflect_Field::slot(f);
328 return InstanceKlass::cast(k)->field_is_flat(slot);
329 } UNSAFE_END
330
331 UNSAFE_ENTRY(jboolean, Unsafe_HasNullMarker(JNIEnv *env, jobject unsafe, jobject o)) {
332 oop f = JNIHandles::resolve_non_null(o);
333 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
334 int slot = java_lang_reflect_Field::slot(f);
335 return InstanceKlass::cast(k)->field_has_null_marker(slot);
336 } UNSAFE_END
337
338 UNSAFE_ENTRY(jint, Unsafe_NullMarkerOffset(JNIEnv *env, jobject unsafe, jobject o)) {
339 oop f = JNIHandles::resolve_non_null(o);
340 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
341 int slot = java_lang_reflect_Field::slot(f);
342 return InstanceKlass::cast(k)->field_null_marker_offset(slot);
343 } UNSAFE_END
344
345 UNSAFE_ENTRY(jint, Unsafe_ArrayLayout(JNIEnv *env, jobject unsafe, jarray array)) {
346 oop ar = JNIHandles::resolve_non_null(array);
347 ArrayKlass* ak = ArrayKlass::cast(ar->klass());
348 if (ak->is_refArray_klass()) {
349 return (jint)LayoutKind::REFERENCE;
350 } else if (ak->is_flatArray_klass()) {
351 return (jint)FlatArrayKlass::cast(ak)->layout_kind();
352 } else {
353 ShouldNotReachHere();
354 return -1;
355 }
356 } UNSAFE_END
357
358 UNSAFE_ENTRY(jint, Unsafe_FieldLayout(JNIEnv *env, jobject unsafe, jobject field)) {
359 assert(field != nullptr, "field must not be null");
360
361 oop reflected = JNIHandles::resolve_non_null(field);
362 oop mirror = java_lang_reflect_Field::clazz(reflected);
363 Klass* k = java_lang_Class::as_Klass(mirror);
364 int slot = java_lang_reflect_Field::slot(reflected);
365 int modifiers = java_lang_reflect_Field::modifiers(reflected);
366
367 if ((modifiers & JVM_ACC_STATIC) != 0) {
368 return (jint)LayoutKind::REFERENCE; // static fields are never flat
369 } else {
370 InstanceKlass* ik = InstanceKlass::cast(k);
371 if (ik->field_is_flat(slot)) {
372 return (jint)ik->inline_layout_info(slot).kind();
373 } else {
374 return (jint)LayoutKind::REFERENCE;
375 }
376 }
377 } UNSAFE_END
378
379 UNSAFE_ENTRY(jarray, Unsafe_NewSpecialArray(JNIEnv *env, jobject unsafe, jclass elmClass, jint len, jint layoutKind)) {
380 oop mirror = JNIHandles::resolve_non_null(elmClass);
381 Klass* klass = java_lang_Class::as_Klass(mirror);
382 klass->initialize(CHECK_NULL);
383 if (len < 0) {
384 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Array length is negative");
385 }
386 if (klass->is_array_klass() || klass->is_identity_class()) {
387 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Element class is not a value class");
388 }
389 if (klass->is_abstract()) {
390 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Element class is abstract");
391 }
392 LayoutKind lk = static_cast<LayoutKind>(layoutKind);
393 if (lk <= LayoutKind::REFERENCE || lk == LayoutKind::NULLABLE_NON_ATOMIC_FLAT || lk >= LayoutKind::UNKNOWN) {
394 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Invalid layout kind");
395 }
396 InlineKlass* vk = InlineKlass::cast(klass);
397 // WARNING: test below will need modifications when flat layouts supported for fields
398 // but not for arrays are introduce (NULLABLE_NON_ATOMIC_FLAT for instance)
399 if (!UseArrayFlattening || !vk->is_layout_supported(lk)) {
400 THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "Layout not supported");
401 }
402 ArrayProperties props = ArrayKlass::array_properties_from_layout(lk);
403 oop array = oopFactory::new_flatArray(vk, len, props, lk, CHECK_NULL);
404 return (jarray) JNIHandles::make_local(THREAD, array);
405 } UNSAFE_END
406
407 UNSAFE_ENTRY(jobject, Unsafe_GetFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc)) {
408 assert(layoutKind != (int)LayoutKind::UNKNOWN, "Sanity");
409 assert(layoutKind != (int)LayoutKind::REFERENCE, "This method handles only flat layouts");
410 oop base = JNIHandles::resolve(obj);
411 if (base == nullptr) {
412 THROW_NULL(vmSymbols::java_lang_NullPointerException());
413 }
414 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
415 InlineKlass* vk = InlineKlass::cast(k);
416 log_unsafe_value_access(base, offset, vk);
417 LayoutKind lk = (LayoutKind)layoutKind;
418 FlatValuePayload payload = FlatValuePayload::construct_from_parts(base, offset, vk, lk);
419 oop v = payload.read(CHECK_NULL);
420 return JNIHandles::make_local(THREAD, v);
421 } UNSAFE_END
422
423 UNSAFE_ENTRY(void, Unsafe_PutFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc, jobject value)) {
424 assert(layoutKind != (int)LayoutKind::UNKNOWN, "Sanity");
425 assert(layoutKind != (int)LayoutKind::REFERENCE, "This method handles only flat layouts");
426 oop base = JNIHandles::resolve(obj);
427 if (base == nullptr) {
428 THROW(vmSymbols::java_lang_NullPointerException());
429 }
430
431 InlineKlass* vk = InlineKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)));
432 log_unsafe_value_access(base, offset, vk);
433 LayoutKind lk = (LayoutKind)layoutKind;
434 FlatValuePayload payload = FlatValuePayload::construct_from_parts(base, offset, vk, lk);
435 payload.write(inlineOop(JNIHandles::resolve(value)), CHECK);
436 } UNSAFE_END
437
438 UNSAFE_ENTRY(jobject, Unsafe_GetReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
439 oop p = JNIHandles::resolve(obj);
440 assert_field_offset_sane(p, offset);
441 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
442 return JNIHandles::make_local(THREAD, v);
443 } UNSAFE_END
444
445 UNSAFE_ENTRY(void, Unsafe_PutReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
446 oop x = JNIHandles::resolve(x_h);
447 oop p = JNIHandles::resolve(obj);
448 assert_field_offset_sane(p, offset);
449 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
450 } UNSAFE_END
451
452 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
453 oop v = *(oop*) (address) addr;
454 return JNIHandles::make_local(THREAD, v);
455 } UNSAFE_END
456
457 #define DEFINE_GETSETOOP(java_type, Type) \
458 \
459 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
460 return MemoryAccess<java_type>(thread, obj, offset).get(); \
461 } UNSAFE_END \
462 \
463 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
464 MemoryAccess<java_type>(thread, obj, offset).put(x); \
465 } UNSAFE_END \
466 \
467 // END DEFINE_GETSETOOP.
468
469 DEFINE_GETSETOOP(jboolean, Boolean)
470 DEFINE_GETSETOOP(jbyte, Byte)
471 DEFINE_GETSETOOP(jshort, Short);
472 DEFINE_GETSETOOP(jchar, Char);
473 DEFINE_GETSETOOP(jint, Int);
474 DEFINE_GETSETOOP(jlong, Long);
475 DEFINE_GETSETOOP(jfloat, Float);
476 DEFINE_GETSETOOP(jdouble, Double);
477
478 #undef DEFINE_GETSETOOP
479
480 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
481 \
482 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
483 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
484 } UNSAFE_END \
485 \
486 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
487 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
488 } UNSAFE_END \
489 \
490 // END DEFINE_GETSETOOP_VOLATILE.
491
492 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
493 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
494 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
495 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
496 DEFINE_GETSETOOP_VOLATILE(jint, Int);
497 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
498 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
499 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
500
501 #undef DEFINE_GETSETOOP_VOLATILE
502
503 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
504 OrderAccess::fence();
505 } UNSAFE_END
506
507 ////// Allocation requests
508
509 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
510 JvmtiVMObjectAllocEventCollector oam;
511 instanceOop i = InstanceKlass::allocate_instance(JNIHandles::resolve_non_null(cls), CHECK_NULL);
512 return JNIHandles::make_local(THREAD, i);
513 } UNSAFE_END
514
515 UNSAFE_LEAF(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
516 size_t sz = (size_t)size;
517
518 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
519
520 void* x = os::malloc(sz, mtOther);
521
522 return addr_to_java(x);
523 } UNSAFE_END
524
525 UNSAFE_LEAF(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
526 void* p = addr_from_java(addr);
527 size_t sz = (size_t)size;
528
529 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
530
531 void* x = os::realloc(p, sz, mtOther);
532
533 return addr_to_java(x);
534 } UNSAFE_END
535
536 UNSAFE_LEAF(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
537 void* p = addr_from_java(addr);
538
539 os::free(p);
540 } UNSAFE_END
541
542 UNSAFE_ENTRY_SCOPED(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
543 size_t sz = (size_t)size;
544
545 oop base = JNIHandles::resolve(obj);
546 void* p = index_oop_from_field_offset_long(base, offset);
547
548 {
549 GuardUnsafeAccess guard(thread);
550 if (StubRoutines::unsafe_setmemory() != nullptr) {
551 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread));
552 StubRoutines::UnsafeSetMemory_stub()(p, sz, value);
553 } else {
554 Copy::fill_to_memory_atomic(p, sz, value);
555 }
556 }
557 } UNSAFE_END
558
559 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
560 size_t sz = (size_t)size;
561
562 oop srcp = JNIHandles::resolve(srcObj);
563 oop dstp = JNIHandles::resolve(dstObj);
564
565 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
566 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
567 {
568 GuardUnsafeAccess guard(thread);
569 if (StubRoutines::unsafe_arraycopy() != nullptr) {
570 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread));
571 StubRoutines::UnsafeArrayCopy_stub()(src, dst, sz);
572 } else {
573 Copy::conjoint_memory_atomic(src, dst, sz);
574 }
575 }
576 } UNSAFE_END
577
578 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
579 size_t sz = (size_t)size;
580 size_t esz = (size_t)elemSize;
581
582 oop srcp = JNIHandles::resolve(srcObj);
583 oop dstp = JNIHandles::resolve(dstObj);
584
585 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
586 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
587
588 {
589 GuardUnsafeAccess guard(thread);
590 Copy::conjoint_swap(src, dst, sz, esz);
591 }
592 } UNSAFE_END
593
594 UNSAFE_LEAF (void, Unsafe_WriteBack0(JNIEnv *env, jobject unsafe, jlong line)) {
595 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
596 #ifdef ASSERT
597 if (TraceMemoryWriteback) {
598 tty->print_cr("Unsafe: writeback 0x%p", addr_from_java(line));
599 }
600 #endif
601
602 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current()));
603 assert(StubRoutines::data_cache_writeback() != nullptr, "sanity");
604 (StubRoutines::DataCacheWriteback_stub())(addr_from_java(line));
605 } UNSAFE_END
606
607 static void doWriteBackSync0(bool is_pre)
608 {
609 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current()));
610 assert(StubRoutines::data_cache_writeback_sync() != nullptr, "sanity");
611 (StubRoutines::DataCacheWritebackSync_stub())(is_pre);
612 }
613
614 UNSAFE_LEAF (void, Unsafe_WriteBackPreSync0(JNIEnv *env, jobject unsafe)) {
615 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
616 #ifdef ASSERT
617 if (TraceMemoryWriteback) {
618 tty->print_cr("Unsafe: writeback pre-sync");
619 }
620 #endif
621
622 doWriteBackSync0(true);
623 } UNSAFE_END
624
625 UNSAFE_LEAF (void, Unsafe_WriteBackPostSync0(JNIEnv *env, jobject unsafe)) {
626 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
627 #ifdef ASSERT
628 if (TraceMemoryWriteback) {
629 tty->print_cr("Unsafe: writeback pre-sync");
630 }
631 #endif
632
633 doWriteBackSync0(false);
634 } UNSAFE_END
635
636 ////// Random queries
637
638 // Finds the object field offset of a field with the matching name, or an error code
639 // Error code -1 is not found, -2 is static field
640 static jlong find_known_instance_field_offset(jclass clazz, jstring name, TRAPS) {
641 assert(clazz != nullptr, "clazz must not be null");
642 assert(name != nullptr, "name must not be null");
643
644 ResourceMark rm(THREAD);
645 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
646
647 InstanceKlass* k = java_lang_Class::as_InstanceKlass(JNIHandles::resolve_non_null(clazz));
648
649 jint offset = -1; // Not found
650 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
651 Symbol *name = fs.name();
652 if (name->equals(utf_name)) {
653 if (!fs.access_flags().is_static()) {
654 offset = fs.offset();
655 } else {
656 offset = -2; // A static field
657 }
658 break;
659 }
660 }
661 if (offset < 0) {
662 return offset; // Error code
663 }
664 return field_offset_from_byte_offset(offset);
665 }
666
667 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
668 assert(field != nullptr, "field must not be null");
669
670 oop reflected = JNIHandles::resolve_non_null(field);
671 oop mirror = java_lang_reflect_Field::clazz(reflected);
672 Klass* k = java_lang_Class::as_Klass(mirror);
673 int slot = java_lang_reflect_Field::slot(reflected);
674 int modifiers = java_lang_reflect_Field::modifiers(reflected);
675
676 if (must_be_static >= 0) {
677 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
678 if (must_be_static != really_is_static) {
679 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
680 }
681 }
682
683 int offset = InstanceKlass::cast(k)->field_offset(slot);
684 return field_offset_from_byte_offset(offset);
685 }
686
687 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
688 return find_field_offset(field, 0, THREAD);
689 } UNSAFE_END
690
691 UNSAFE_ENTRY(jlong, Unsafe_KnownObjectFieldOffset0(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
692 return find_known_instance_field_offset(c, name, THREAD);
693 } UNSAFE_END
694
695 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
696 return find_field_offset(field, 1, THREAD);
697 } UNSAFE_END
698
699 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
700 assert(field != nullptr, "field must not be null");
701
702 // Note: In this VM implementation, a field address is always a short
703 // offset from the base of a klass metaobject. Thus, the full dynamic
704 // range of the return type is never used. However, some implementations
705 // might put the static field inside an array shared by many classes,
706 // or even at a fixed address, in which case the address could be quite
707 // large. In that last case, this function would return null, since
708 // the address would operate alone, without any base pointer.
709
710 oop reflected = JNIHandles::resolve_non_null(field);
711 oop mirror = java_lang_reflect_Field::clazz(reflected);
712 int modifiers = java_lang_reflect_Field::modifiers(reflected);
713
714 if ((modifiers & JVM_ACC_STATIC) == 0) {
715 THROW_NULL(vmSymbols::java_lang_IllegalArgumentException());
716 }
717
718 return JNIHandles::make_local(THREAD, mirror);
719 } UNSAFE_END
720
721 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
722 assert(clazz != nullptr, "clazz must not be null");
723
724 oop mirror = JNIHandles::resolve_non_null(clazz);
725
726 Klass* klass = java_lang_Class::as_Klass(mirror);
727 if (klass != nullptr && klass->should_be_initialized()) {
728 InstanceKlass* k = InstanceKlass::cast(klass);
729 k->initialize(CHECK);
730 }
731 }
732 UNSAFE_END
733
734 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
735 assert(clazz != nullptr, "clazz must not be null");
736
737 oop mirror = JNIHandles::resolve_non_null(clazz);
738 Klass* klass = java_lang_Class::as_Klass(mirror);
739
740 if (klass != nullptr && klass->should_be_initialized()) {
741 return true;
742 }
743
744 return false;
745 }
746 UNSAFE_END
747
748 UNSAFE_ENTRY(void, Unsafe_NotifyStrictStaticAccess0(JNIEnv *env, jobject unsafe, jobject clazz,
749 jlong sfoffset, jboolean writing)) {
750 assert(clazz != nullptr, "clazz must not be null");
751
752 oop mirror = JNIHandles::resolve_non_null(clazz);
753 Klass* klass = java_lang_Class::as_Klass(mirror);
754
755 if (klass != nullptr && klass->is_instance_klass()) {
756 InstanceKlass* ik = InstanceKlass::cast(klass);
757 fieldDescriptor fd;
758 if (ik->find_local_field_from_offset((int)sfoffset, true, &fd)) {
759 // Note: The Unsafe API takes an OFFSET, but the InstanceKlass wants the INDEX.
760 // We could surface field indexes into Unsafe, but that's too much churn.
761 ik->notify_strict_static_access(fd.index(), writing, CHECK);
762 return;
763 }
764 }
765 THROW(vmSymbols::java_lang_InternalError());
766 }
767 UNSAFE_END
768
769 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
770 assert(clazz != nullptr, "clazz must not be null");
771
772 oop mirror = JNIHandles::resolve_non_null(clazz);
773 Klass* k = java_lang_Class::as_Klass(mirror);
774
775 if (k == nullptr || !k->is_array_klass()) {
776 THROW(vmSymbols::java_lang_InvalidClassException());
777 } else if (k->is_typeArray_klass()) {
778 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
779 base = tak->array_header_in_bytes();
780 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
781 scale = (1 << tak->log2_element_size());
782 } else if (k->is_objArray_klass()) {
783 Klass* ek = ObjArrayKlass::cast(k)->element_klass();
784 if (!ek->is_identity_class() && !ek->is_abstract()) {
785 // Arrays of a concrete value class type can have multiple layouts
786 // There's no good value to return, so throwing an exception is the way out
787 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "Arrays of a concrete value class don't have a single base and offset");
788 }
789 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
790 scale = heapOopSize;
791 } else {
792 ShouldNotReachHere();
793 }
794 }
795
796 UNSAFE_ENTRY(jint, Unsafe_ArrayInstanceBaseOffset0(JNIEnv *env, jobject unsafe, jarray array)) {
797 assert(array != nullptr, "array must not be null");
798 oop ar = JNIHandles::resolve_non_null(array);
799 assert(ar->is_array(), "Must be an array");
800 ArrayKlass* ak = ArrayKlass::cast(ar->klass());
801 if (ak->is_refArray_klass()) {
802 return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
803 } else if (ak->is_flatArray_klass()) {
804 FlatArrayKlass* fak = FlatArrayKlass::cast(ak);
805 return fak->array_header_in_bytes();
806 } else {
807 ShouldNotReachHere();
808 }
809 } UNSAFE_END
810
811 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
812 int base = 0, scale = 0;
813 getBaseAndScale(base, scale, clazz, CHECK_0);
814
815 return field_offset_from_byte_offset(base);
816 } UNSAFE_END
817
818
819 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
820 int base = 0, scale = 0;
821 getBaseAndScale(base, scale, clazz, CHECK_0);
822
823 // This VM packs both fields and array elements down to the byte.
824 // But watch out: If this changes, so that array references for
825 // a given primitive type (say, T_BOOLEAN) use different memory units
826 // than fields, this method MUST return zero for such arrays.
827 // For example, the VM used to store sub-word sized fields in full
828 // words in the object layout, so that accessors like getByte(Object,int)
829 // did not really do what one might expect for arrays. Therefore,
830 // this function used to report a zero scale factor, so that the user
831 // would know not to attempt to access sub-word array elements.
832 // // Code for unpacked fields:
833 // if (scale < wordSize) return 0;
834
835 // The following allows for a pretty general fieldOffset cookie scheme,
836 // but requires it to be linear in byte offset.
837 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
838 } UNSAFE_END
839
840 UNSAFE_ENTRY(jint, Unsafe_ArrayInstanceIndexScale0(JNIEnv *env, jobject unsafe, jarray array)) {
841 assert(array != nullptr, "array must not be null");
842 oop ar = JNIHandles::resolve_non_null(array);
843 assert(ar->is_array(), "Must be an array");
844 ArrayKlass* ak = ArrayKlass::cast(ar->klass());
845 if (ak->is_refArray_klass()) {
846 return heapOopSize;
847 } else if (ak->is_flatArray_klass()) {
848 FlatArrayKlass* fak = FlatArrayKlass::cast(ak);
849 return fak->element_byte_size();
850 } else {
851 ShouldNotReachHere();
852 }
853 } UNSAFE_END
854
855 UNSAFE_ENTRY(jarray, Unsafe_GetFieldMap0(JNIEnv* env, jobject unsafe, jclass clazz)) {
856 oop mirror = JNIHandles::resolve_non_null(clazz);
857 Klass* k = java_lang_Class::as_Klass(mirror);
858
859 if (!k->is_inline_klass()) {
860 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Argument is not a concrete value class");
861 }
862 InlineKlass* vk = InlineKlass::cast(k);
863 oop map = mirror->obj_field(vk->acmp_maps_offset());
864 return (jarray) JNIHandles::make_local(THREAD, map);
865 } UNSAFE_END
866
867 UNSAFE_ENTRY(jlong, Unsafe_GetObjectSize0(JNIEnv* env, jobject o, jobject obj))
868 oop p = JNIHandles::resolve(obj);
869 return p->size() * HeapWordSize;
870 UNSAFE_END
871
872 static inline void throw_new(JNIEnv *env, const char *ename) {
873 jclass cls = env->FindClass(ename);
874 if (env->ExceptionCheck()) {
875 env->ExceptionClear();
876 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
877 return;
878 }
879
880 env->ThrowNew(cls, nullptr);
881 }
882
883 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
884 // Code lifted from JDK 1.3 ClassLoader.c
885
886 jbyte *body;
887 char *utfName = nullptr;
888 jclass result = nullptr;
889 char buf[128];
890
891 assert(data != nullptr, "Class bytes must not be null");
892 assert(length >= 0, "length must not be negative: %d", length);
893
894 if (UsePerfData) {
895 ClassLoader::unsafe_defineClassCallCounter()->inc();
896 }
897
898 body = NEW_C_HEAP_ARRAY_RETURN_NULL(jbyte, length, mtInternal);
899 if (body == nullptr) {
900 throw_new(env, "java/lang/OutOfMemoryError");
901 return nullptr;
902 }
903
904 env->GetByteArrayRegion(data, offset, length, body);
905 if (env->ExceptionCheck()) {
906 goto free_body;
907 }
908
909 if (name != nullptr) {
910 uint len = env->GetStringUTFLength(name);
911 int unicode_len = env->GetStringLength(name);
912
913 if (len >= sizeof(buf)) {
914 utfName = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len + 1, mtInternal);
915 if (utfName == nullptr) {
916 throw_new(env, "java/lang/OutOfMemoryError");
917 goto free_body;
918 }
919 } else {
920 utfName = buf;
921 }
922
923 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
924
925 for (uint i = 0; i < len; i++) {
926 if (utfName[i] == '.') utfName[i] = '/';
927 }
928 }
929
930 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
931
932 if (utfName && utfName != buf) {
933 FREE_C_HEAP_ARRAY(char, utfName);
934 }
935
936 free_body:
937 FREE_C_HEAP_ARRAY(jbyte, body);
938 return result;
939 }
940
941
942 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
943 ThreadToNativeFromVM ttnfv(thread);
944
945 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
946 } UNSAFE_END
947
948
949 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
950 ThreadToNativeFromVM ttnfv(thread);
951 env->Throw(thr);
952 } UNSAFE_END
953
954 // JSR166 ------------------------------------------------------------------
955
956 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
957 oop x = JNIHandles::resolve(x_h);
958 oop e = JNIHandles::resolve(e_h);
959 oop p = JNIHandles::resolve(obj);
960 assert_field_offset_sane(p, offset);
961 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
962 return JNIHandles::make_local(THREAD, res);
963 } UNSAFE_END
964
965 UNSAFE_ENTRY_SCOPED(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
966 oop p = JNIHandles::resolve(obj);
967 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
968 return AtomicAccess::cmpxchg(addr, e, x);
969 } UNSAFE_END
970
971 UNSAFE_ENTRY_SCOPED(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
972 oop p = JNIHandles::resolve(obj);
973 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
974 return AtomicAccess::cmpxchg(addr, e, x);
975 } UNSAFE_END
976
977 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
978 oop x = JNIHandles::resolve(x_h);
979 oop e = JNIHandles::resolve(e_h);
980 oop p = JNIHandles::resolve(obj);
981 assert_field_offset_sane(p, offset);
982 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
983 return ret == e;
984 } UNSAFE_END
985
986 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
987 oop p = JNIHandles::resolve(obj);
988 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
989 return AtomicAccess::cmpxchg(addr, e, x) == e;
990 } UNSAFE_END
991
992 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
993 oop p = JNIHandles::resolve(obj);
994 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
995 return AtomicAccess::cmpxchg(addr, e, x) == e;
996 } UNSAFE_END
997
998 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) {
999 assert(event != nullptr, "invariant");
1000 event->set_parkedClass((obj != nullptr) ? obj->klass() : nullptr);
1001 event->set_timeout(timeout_nanos);
1002 event->set_until(until_epoch_millis);
1003 event->set_address((obj != nullptr) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1004 event->commit();
1005 }
1006
1007 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1008 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1009 EventThreadPark event;
1010
1011 JavaThreadParkedState jtps(thread, time != 0);
1012 thread->parker()->park(isAbsolute != 0, time);
1013 if (event.should_commit()) {
1014 const oop obj = thread->current_park_blocker();
1015 if (time == 0) {
1016 post_thread_park_event(&event, obj, min_jlong, min_jlong);
1017 } else {
1018 if (isAbsolute != 0) {
1019 post_thread_park_event(&event, obj, min_jlong, time);
1020 } else {
1021 post_thread_park_event(&event, obj, time, min_jlong);
1022 }
1023 }
1024 }
1025 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1026 } UNSAFE_END
1027
1028 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1029 if (jthread != nullptr) {
1030 oop thread_oop = JNIHandles::resolve_non_null(jthread);
1031 // Get the JavaThread* stored in the java.lang.Thread object _before_
1032 // the embedded ThreadsListHandle is constructed so we know if the
1033 // early life stage of the JavaThread* is protected. We use acquire
1034 // here to ensure that if we see a non-nullptr value, then we also
1035 // see the main ThreadsList updates from the JavaThread* being added.
1036 FastThreadsListHandle ftlh(thread_oop, java_lang_Thread::thread_acquire(thread_oop));
1037 JavaThread* thr = ftlh.protected_java_thread();
1038 if (thr != nullptr) {
1039 // The still live JavaThread* is protected by the FastThreadsListHandle
1040 // so it is safe to access.
1041 Parker* p = thr->parker();
1042 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1043 p->unpark();
1044 }
1045 } // FastThreadsListHandle is destroyed here.
1046 } UNSAFE_END
1047
1048 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1049 const int max_nelem = 3;
1050 double la[max_nelem];
1051 jint ret;
1052
1053 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1054 assert(a->is_typeArray(), "must be type array");
1055
1056 ret = os::loadavg(la, nelem);
1057 if (ret == -1) {
1058 return -1;
1059 }
1060
1061 // if successful, ret is the number of samples actually retrieved.
1062 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1063 switch(ret) {
1064 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1065 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1066 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1067 }
1068
1069 return ret;
1070 } UNSAFE_END
1071
1072
1073 /// JVM_RegisterUnsafeMethods
1074
1075 #define ADR "J"
1076
1077 #define LANG "Ljava/lang/"
1078
1079 #define OBJ LANG "Object;"
1080 #define CLS LANG "Class;"
1081 #define FLD LANG "reflect/Field;"
1082 #define THR LANG "Throwable;"
1083
1084 #define OBJ_ARR "[" OBJ
1085
1086 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1087 #define DAC_Args CLS "[B[" OBJ
1088
1089 #define CC (char*) /*cast a literal from (const char*)*/
1090 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1091
1092 #define DECLARE_GETPUTOOP(Type, Desc) \
1093 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1094 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1095 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1096 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1097
1098
1099 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1100 {CC "getReference", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetReference)},
1101 {CC "putReference", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReference)},
1102 {CC "getReferenceVolatile", CC "(" OBJ "J)" OBJ, FN_PTR(Unsafe_GetReferenceVolatile)},
1103 {CC "putReferenceVolatile", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReferenceVolatile)},
1104
1105 {CC "isFlatField0", CC "(" OBJ ")Z", FN_PTR(Unsafe_IsFlatField)},
1106 {CC "hasNullMarker0", CC "(" OBJ ")Z", FN_PTR(Unsafe_HasNullMarker)},
1107 {CC "nullMarkerOffset0", CC "(" OBJ ")I", FN_PTR(Unsafe_NullMarkerOffset)},
1108 {CC "arrayLayout0", CC "(" OBJ_ARR ")I", FN_PTR(Unsafe_ArrayLayout)},
1109 {CC "fieldLayout0", CC "(" OBJ ")I", FN_PTR(Unsafe_FieldLayout)},
1110 {CC "newSpecialArray", CC "(" CLS "II)[" OBJ, FN_PTR(Unsafe_NewSpecialArray)},
1111 {CC "getFlatValue", CC "(" OBJ "JI" CLS ")" OBJ, FN_PTR(Unsafe_GetFlatValue)},
1112 {CC "putFlatValue", CC "(" OBJ "JI" CLS OBJ ")V", FN_PTR(Unsafe_PutFlatValue)},
1113 {CC "valueHeaderSize", CC "(" CLS ")J", FN_PTR(Unsafe_ValueHeaderSize)},
1114 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1115
1116 DECLARE_GETPUTOOP(Boolean, Z),
1117 DECLARE_GETPUTOOP(Byte, B),
1118 DECLARE_GETPUTOOP(Short, S),
1119 DECLARE_GETPUTOOP(Char, C),
1120 DECLARE_GETPUTOOP(Int, I),
1121 DECLARE_GETPUTOOP(Long, J),
1122 DECLARE_GETPUTOOP(Float, F),
1123 DECLARE_GETPUTOOP(Double, D),
1124
1125 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1126 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1127 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1128
1129 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1130 {CC "knownObjectFieldOffset0", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_KnownObjectFieldOffset0)},
1131 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1132 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1133 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1134 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1135 {CC "arrayInstanceBaseOffset0", CC "(" OBJ_ARR ")I", FN_PTR(Unsafe_ArrayInstanceBaseOffset0)},
1136 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1137 {CC "arrayInstanceIndexScale0", CC "(" OBJ_ARR ")I", FN_PTR(Unsafe_ArrayInstanceIndexScale0)},
1138 {CC "getFieldMap0", CC "(Ljava/lang/Class;)[I", FN_PTR(Unsafe_GetFieldMap0)},
1139 {CC "getObjectSize0", CC "(Ljava/lang/Object;)J", FN_PTR(Unsafe_GetObjectSize0)},
1140
1141 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1142 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1143 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1144 {CC "compareAndSetReference",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetReference)},
1145 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1146 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1147 {CC "compareAndExchangeReference", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeReference)},
1148 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1149 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1150
1151 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1152 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1153
1154 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1155
1156 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1157 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1158 {CC "writeback0", CC "(" "J" ")V", FN_PTR(Unsafe_WriteBack0)},
1159 {CC "writebackPreSync0", CC "()V", FN_PTR(Unsafe_WriteBackPreSync0)},
1160 {CC "writebackPostSync0", CC "()V", FN_PTR(Unsafe_WriteBackPostSync0)},
1161 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1162
1163 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1164 {CC "notifyStrictStaticAccess0", CC "(" CLS "JZ)V", FN_PTR(Unsafe_NotifyStrictStaticAccess0)},
1165
1166 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1167 };
1168
1169 #undef CC
1170 #undef FN_PTR
1171
1172 #undef ADR
1173 #undef LANG
1174 #undef OBJ
1175 #undef CLS
1176 #undef FLD
1177 #undef THR
1178 #undef DC_Args
1179 #undef DAC_Args
1180
1181 #undef DECLARE_GETPUTOOP
1182
1183
1184 // This function is exported, used by NativeLookup.
1185 // The Unsafe_xxx functions above are called only from the interpreter.
1186 // The optimizer looks at names and signatures to recognize
1187 // individual functions.
1188
1189 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1190 ThreadToNativeFromVM ttnfv(thread);
1191
1192 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1193 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1194 } JVM_END