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