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/typeArrayOop.inline.hpp"
49 #include "oops/valuePayload.hpp"
50 #include "prims/jvmtiExport.hpp"
51 #include "prims/unsafe.hpp"
52 #include "runtime/fieldDescriptor.inline.hpp"
53 #include "runtime/globals.hpp"
54 #include "runtime/handles.inline.hpp"
55 #include "runtime/interfaceSupport.inline.hpp"
56 #include "runtime/javaThread.inline.hpp"
57 #include "runtime/jniHandles.inline.hpp"
58 #include "runtime/orderAccess.hpp"
59 #include "runtime/reflection.hpp"
60 #include "runtime/sharedRuntime.hpp"
61 #include "runtime/stubRoutines.hpp"
62 #include "runtime/threadSMR.hpp"
63 #include "runtime/vm_version.hpp"
64 #include "runtime/vmOperations.hpp"
65 #include "sanitizers/ub.hpp"
66 #include "services/threadService.hpp"
67 #include "utilities/align.hpp"
68 #include "utilities/copy.hpp"
69 #include "utilities/dtrace.hpp"
70 #include "utilities/macros.hpp"
71
72 /**
73 * Implementation of the jdk.internal.misc.Unsafe class
74 */
75
76
77 #define MAX_OBJECT_SIZE \
78 ( arrayOopDesc::base_offset_in_bytes(T_DOUBLE) \
79 + ((julong)max_jint * sizeof(double)) )
80
81 #define UNSAFE_ENTRY(result_type, header) \
82 JVM_ENTRY(static result_type, header)
83
84 #define UNSAFE_LEAF(result_type, header) \
85 JVM_LEAF(static result_type, header)
86
87 // All memory access methods (e.g. getInt, copyMemory) must use this macro.
88 // We call these methods "scoped" methods, as access to these methods is
89 // typically governed by a "scope" (a MemorySessionImpl object), and no
90 // access is allowed when the scope is no longer alive.
91 //
92 // Closing a scope object (cf. scopedMemoryAccess.cpp) can install
93 // an async exception during a safepoint. When that happens,
94 // scoped methods are not allowed to touch the underlying memory (as that
95 // memory might have been released). Therefore, when entering a scoped method
96 // we check if an async exception has been installed, and return immediately
97 // if that is the case.
98 //
99 // As a rule, we disallow safepoints in the middle of a scoped method.
100 // If an async exception handshake were installed in such a safepoint,
101 // memory access might still occur before the handshake is honored by
102 // the accessing thread.
103 //
104 // Corollary: as threads in native state are considered to be at a safepoint,
105 // scoped methods must NOT be executed while in the native thread state.
106 // Because of this, there can be no UNSAFE_LEAF_SCOPED.
107 #define UNSAFE_ENTRY_SCOPED(result_type, header) \
108 JVM_ENTRY(static result_type, header) \
109 if (thread->has_async_exception_condition()) {return (result_type)0;}
110
111 #define UNSAFE_END JVM_END
112
113
114 static inline void* addr_from_java(jlong addr) {
115 // This assert fails in a variety of ways on 32-bit systems.
116 // It is impossible to predict whether native code that converts
117 // pointers to longs will sign-extend or zero-extend the addresses.
118 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
119 return (void*)(uintptr_t)addr;
120 }
121
122 static inline jlong addr_to_java(void* p) {
123 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
124 return (uintptr_t)p;
125 }
126
127
128 // Note: The VM's obj_field and related accessors use byte-scaled
129 // ("unscaled") offsets, just as the unsafe methods do.
130
131 // However, the method Unsafe.fieldOffset explicitly declines to
132 // guarantee this. The field offset values manipulated by the Java user
133 // through the Unsafe API are opaque cookies that just happen to be byte
134 // offsets. We represent this state of affairs by passing the cookies
135 // through conversion functions when going between the VM and the Unsafe API.
136 // The conversion functions just happen to be no-ops at present.
137
138 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
139 return field_offset;
140 }
141
142 static inline int field_offset_from_byte_offset(int byte_offset) {
143 return byte_offset;
144 }
145
146 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
147 #ifdef ASSERT
148 jlong byte_offset = field_offset_to_byte_offset(field_offset);
149
150 if (p != nullptr) {
151 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
152 if (byte_offset == (jint)byte_offset) {
153 void* ptr_plus_disp = cast_from_oop<address>(p) + byte_offset;
154 assert(p->field_addr<void>((jint)byte_offset) == ptr_plus_disp,
155 "raw [ptr+disp] must be consistent with oop::field_addr");
156 }
157 jlong p_size = HeapWordSize * (jlong)(p->size());
158 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
159 }
160 #endif
161 }
162
163 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
164 assert_field_offset_sane(p, field_offset);
165 uintptr_t base_address = cast_from_oop<uintptr_t>(p);
166 uintptr_t byte_offset = (uintptr_t)field_offset_to_byte_offset(field_offset);
167 return (void*)(base_address + byte_offset);
168 }
169
170 // Externally callable versions:
171 // (Use these in compiler intrinsics which emulate unsafe primitives.)
172 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
173 return field_offset;
174 }
175 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
176 return byte_offset;
177 }
178
179 ///// Data read/writes on the Java heap and in native (off-heap) memory
180
181 /**
182 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
183 */
184 class GuardUnsafeAccess {
185 JavaThread* _thread;
186
187 public:
188 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
189 // native/off-heap access which may raise SIGBUS if accessing
190 // memory mapped file data in a region of the file which has
191 // been truncated and is now invalid.
192 _thread->set_doing_unsafe_access(true);
193 }
194
195 ~GuardUnsafeAccess() {
196 _thread->set_doing_unsafe_access(false);
197 }
198 };
199
200 /**
201 * Helper class for accessing memory.
202 *
203 * Normalizes values and wraps accesses in
204 * JavaThread::doing_unsafe_access() if needed.
205 */
206 template <typename T>
207 class MemoryAccess : StackObj {
208 JavaThread* _thread;
209 oop _obj;
210 ptrdiff_t _offset;
211
212 // Resolves and returns the address of the memory access.
213 // This raw memory access may fault, so we make sure it happens within the
214 // guarded scope by making the access volatile at least. Since the store
215 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
216 // can not be reordered by the compiler. Therefore, if the access triggers
217 // a fault, we will know that Thread::doing_unsafe_access() returns true.
218 volatile T* addr() {
219 void* addr = index_oop_from_field_offset_long(_obj, _offset);
220 return static_cast<volatile T*>(addr);
221 }
222
223 template <typename U>
224 U normalize_for_write(U x) {
225 return x;
226 }
227
228 jboolean normalize_for_write(jboolean x) {
229 return x & 1;
230 }
231
232 template <typename U>
233 U normalize_for_read(U x) {
234 return x;
235 }
236
237 jboolean normalize_for_read(jboolean x) {
238 return x != 0;
239 }
240
241 public:
242 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
243 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
244 assert_field_offset_sane(_obj, offset);
245 }
246
247 T get() {
248 GuardUnsafeAccess guard(_thread);
249 return normalize_for_read(*addr());
250 }
251
252 // we use this method at some places for writing to 0 e.g. to cause a crash;
253 // ubsan does not know that this is the desired behavior
254 ATTRIBUTE_NO_UBSAN
255 void put(T x) {
256 GuardUnsafeAccess guard(_thread);
257 assert(_obj == nullptr || !_obj->is_inline_type() || _obj->mark().is_larval_state(), "must be an object instance or a larval inline type");
258 *addr() = normalize_for_write(x);
259 }
260
261 T get_volatile() {
262 GuardUnsafeAccess guard(_thread);
263 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
264 return normalize_for_read(ret);
265 }
266
267 void put_volatile(T x) {
268 GuardUnsafeAccess guard(_thread);
269 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
270 }
271 };
272
273 #ifdef ASSERT
274 /*
275 * Get the field descriptor of the field of the given object at the given offset.
276 */
277 static bool get_field_descriptor(oop p, jlong offset, fieldDescriptor* fd) {
278 bool found = false;
279 Klass* k = p->klass();
280 if (k->is_instance_klass()) {
281 InstanceKlass* ik = InstanceKlass::cast(k);
282 found = ik->find_field_from_offset((int)offset, false, fd);
283 if (!found && ik->is_mirror_instance_klass()) {
284 Klass* k2 = java_lang_Class::as_Klass(p);
285 if (k2->is_instance_klass()) {
286 ik = InstanceKlass::cast(k2);
287 found = ik->find_field_from_offset((int)offset, true, fd);
288 }
289 }
290 }
291 return found;
292 }
293 #endif // ASSERT
294
295 static void assert_and_log_unsafe_value_access(oop p, jlong offset, InlineKlass* vk) {
296 Klass* k = p->klass();
297 #ifdef ASSERT
298 if (k->is_instance_klass()) {
299 assert_field_offset_sane(p, offset);
300 fieldDescriptor fd;
301 bool found = get_field_descriptor(p, offset, &fd);
302 if (found) {
303 assert(found, "value field not found");
304 assert(fd.is_flat(), "field not flat");
305 } else {
306 if (log_is_enabled(Trace, valuetypes)) {
307 log_trace(valuetypes)("not a field in %s at offset " UINT64_FORMAT_X,
308 p->klass()->external_name(), (uint64_t)offset);
309 }
310 }
311 } else if (k->is_flatArray_klass()) {
312 FlatArrayKlass* vak = FlatArrayKlass::cast(k);
313 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
314 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper());
315 assert(dest == (cast_from_oop<address>(p) + offset), "invalid offset");
316 } else {
317 ShouldNotReachHere();
318 }
319 #endif // ASSERT
320 if (log_is_enabled(Trace, valuetypes)) {
321 if (k->is_flatArray_klass()) {
322 FlatArrayKlass* vak = FlatArrayKlass::cast(k);
323 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
324 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper());
325 log_trace(valuetypes)("%s array type %s index %d element size %d offset " UINT64_FORMAT_X " at " INTPTR_FORMAT,
326 p->klass()->external_name(), vak->external_name(),
327 index, vak->element_byte_size(), (uint64_t)offset, p2i(dest));
328 } else {
329 log_trace(valuetypes)("%s field type %s at offset " UINT64_FORMAT_X,
330 p->klass()->external_name(), vk->external_name(), (uint64_t)offset);
331 }
332 }
333 }
334
335 // These functions allow a null base pointer with an arbitrary address.
336 // But if the base pointer is non-null, the offset should make some sense.
337 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
338 UNSAFE_ENTRY(jobject, Unsafe_GetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
339 oop p = JNIHandles::resolve(obj);
340 assert_field_offset_sane(p, offset);
341 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
342 return JNIHandles::make_local(THREAD, v);
343 } UNSAFE_END
344
345 UNSAFE_ENTRY(void, Unsafe_PutReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
346 oop x = JNIHandles::resolve(x_h);
347 oop p = JNIHandles::resolve(obj);
348 assert_field_offset_sane(p, offset);
349 assert(!p->is_inline_type() || p->mark().is_larval_state(), "must be an object instance or a larval inline type");
350 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
351 } UNSAFE_END
352
353 UNSAFE_ENTRY(jlong, Unsafe_ValueHeaderSize(JNIEnv *env, jobject unsafe, jclass c)) {
354 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
355 InlineKlass* vk = InlineKlass::cast(k);
356 return vk->payload_offset();
357 } UNSAFE_END
358
359 UNSAFE_ENTRY(jboolean, Unsafe_IsFlatField(JNIEnv *env, jobject unsafe, jobject o)) {
360 oop f = JNIHandles::resolve_non_null(o);
361 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
362 int slot = java_lang_reflect_Field::slot(f);
363 return InstanceKlass::cast(k)->field_is_flat(slot);
364 } UNSAFE_END
365
366 UNSAFE_ENTRY(jboolean, Unsafe_HasNullMarker(JNIEnv *env, jobject unsafe, jobject o)) {
367 oop f = JNIHandles::resolve_non_null(o);
368 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
369 int slot = java_lang_reflect_Field::slot(f);
370 return InstanceKlass::cast(k)->field_has_null_marker(slot);
371 } UNSAFE_END
372
373 UNSAFE_ENTRY(jint, Unsafe_NullMarkerOffset(JNIEnv *env, jobject unsafe, jobject o)) {
374 oop f = JNIHandles::resolve_non_null(o);
375 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f));
376 int slot = java_lang_reflect_Field::slot(f);
377 return InstanceKlass::cast(k)->field_null_marker_offset(slot);
378 } UNSAFE_END
379
380 UNSAFE_ENTRY(jint, Unsafe_ArrayLayout(JNIEnv *env, jobject unsafe, jarray array)) {
381 oop ar = JNIHandles::resolve_non_null(array);
382 ArrayKlass* ak = ArrayKlass::cast(ar->klass());
383 if (ak->is_refArray_klass()) {
384 return (jint)LayoutKind::REFERENCE;
385 } else if (ak->is_flatArray_klass()) {
386 return (jint)FlatArrayKlass::cast(ak)->layout_kind();
387 } else {
388 ShouldNotReachHere();
389 return -1;
390 }
391 } UNSAFE_END
392
393 UNSAFE_ENTRY(jint, Unsafe_FieldLayout(JNIEnv *env, jobject unsafe, jobject field)) {
394 assert(field != nullptr, "field must not be null");
395
396 oop reflected = JNIHandles::resolve_non_null(field);
397 oop mirror = java_lang_reflect_Field::clazz(reflected);
398 Klass* k = java_lang_Class::as_Klass(mirror);
399 int slot = java_lang_reflect_Field::slot(reflected);
400 int modifiers = java_lang_reflect_Field::modifiers(reflected);
401
402 if ((modifiers & JVM_ACC_STATIC) != 0) {
403 return (jint)LayoutKind::REFERENCE; // static fields are never flat
404 } else {
405 InstanceKlass* ik = InstanceKlass::cast(k);
406 if (ik->field_is_flat(slot)) {
407 return (jint)ik->inline_layout_info(slot).kind();
408 } else {
409 return (jint)LayoutKind::REFERENCE;
410 }
411 }
412 } UNSAFE_END
413
414 UNSAFE_ENTRY(jarray, Unsafe_NewSpecialArray(JNIEnv *env, jobject unsafe, jclass elmClass, jint len, jint layoutKind)) {
415 oop mirror = JNIHandles::resolve_non_null(elmClass);
416 Klass* klass = java_lang_Class::as_Klass(mirror);
417 klass->initialize(CHECK_NULL);
418 if (len < 0) {
419 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Array length is negative");
420 }
421 if (klass->is_array_klass() || klass->is_identity_class()) {
422 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Element class is not a value class");
423 }
424 if (klass->is_abstract()) {
425 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Element class is abstract");
426 }
427 LayoutKind lk = static_cast<LayoutKind>(layoutKind);
428 if (lk <= LayoutKind::REFERENCE || lk == LayoutKind::NULLABLE_NON_ATOMIC_FLAT || lk >= LayoutKind::UNKNOWN) {
429 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Invalid layout kind");
430 }
431 InlineKlass* vk = InlineKlass::cast(klass);
432 // WARNING: test below will need modifications when flat layouts supported for fields
433 // but not for arrays are introduce (NULLABLE_NON_ATOMIC_FLAT for instance)
434 if (!UseArrayFlattening || !vk->is_layout_supported(lk)) {
435 THROW_MSG_NULL(vmSymbols::java_lang_UnsupportedOperationException(), "Layout not supported");
436 }
437 ArrayProperties props = ArrayKlass::array_properties_from_layout(lk);
438 oop array = oopFactory::new_flatArray(vk, len, props, lk, CHECK_NULL);
439 return (jarray) JNIHandles::make_local(THREAD, array);
440 } UNSAFE_END
441
442 UNSAFE_ENTRY(jobject, Unsafe_GetFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc)) {
443 assert(layoutKind != (int)LayoutKind::UNKNOWN, "Sanity");
444 assert(layoutKind != (int)LayoutKind::REFERENCE, "This method handles only flat layouts");
445 oop base = JNIHandles::resolve(obj);
446 if (base == nullptr) {
447 THROW_NULL(vmSymbols::java_lang_NullPointerException());
448 }
449 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
450 InlineKlass* vk = InlineKlass::cast(k);
451 assert_and_log_unsafe_value_access(base, offset, vk);
452 LayoutKind lk = (LayoutKind)layoutKind;
453 FlatValuePayload payload = FlatValuePayload::construct_from_parts(base, offset, vk, lk);
454 oop v = payload.read(CHECK_NULL);
455 return JNIHandles::make_local(THREAD, v);
456 } UNSAFE_END
457
458 UNSAFE_ENTRY(void, Unsafe_PutFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc, jobject value)) {
459 assert(layoutKind != (int)LayoutKind::UNKNOWN, "Sanity");
460 assert(layoutKind != (int)LayoutKind::REFERENCE, "This method handles only flat layouts");
461 oop base = JNIHandles::resolve(obj);
462 if (base == nullptr) {
463 THROW(vmSymbols::java_lang_NullPointerException());
464 }
465
466 InlineKlass* vk = InlineKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)));
467 assert_and_log_unsafe_value_access(base, offset, vk);
468 LayoutKind lk = (LayoutKind)layoutKind;
469 FlatValuePayload payload = FlatValuePayload::construct_from_parts(base, offset, vk, lk);
470 payload.write(inlineOop(JNIHandles::resolve(value)), CHECK);
471 } UNSAFE_END
472
473 UNSAFE_ENTRY(jobject, Unsafe_GetReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
474 oop p = JNIHandles::resolve(obj);
475 assert_field_offset_sane(p, offset);
476 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
477 return JNIHandles::make_local(THREAD, v);
478 } UNSAFE_END
479
480 UNSAFE_ENTRY(void, Unsafe_PutReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
481 oop x = JNIHandles::resolve(x_h);
482 oop p = JNIHandles::resolve(obj);
483 assert_field_offset_sane(p, offset);
484 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
485 } UNSAFE_END
486
487 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
488 oop v = *(oop*) (address) addr;
489 return JNIHandles::make_local(THREAD, v);
490 } UNSAFE_END
491
492 #define DEFINE_GETSETOOP(java_type, Type) \
493 \
494 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
495 return MemoryAccess<java_type>(thread, obj, offset).get(); \
496 } UNSAFE_END \
497 \
498 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
499 MemoryAccess<java_type>(thread, obj, offset).put(x); \
500 } UNSAFE_END \
501 \
502 // END DEFINE_GETSETOOP.
503
504 DEFINE_GETSETOOP(jboolean, Boolean)
505 DEFINE_GETSETOOP(jbyte, Byte)
506 DEFINE_GETSETOOP(jshort, Short);
507 DEFINE_GETSETOOP(jchar, Char);
508 DEFINE_GETSETOOP(jint, Int);
509 DEFINE_GETSETOOP(jlong, Long);
510 DEFINE_GETSETOOP(jfloat, Float);
511 DEFINE_GETSETOOP(jdouble, Double);
512
513 #undef DEFINE_GETSETOOP
514
515 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
516 \
517 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
518 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
519 } UNSAFE_END \
520 \
521 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
522 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
523 } UNSAFE_END \
524 \
525 // END DEFINE_GETSETOOP_VOLATILE.
526
527 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
528 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
529 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
530 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
531 DEFINE_GETSETOOP_VOLATILE(jint, Int);
532 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
533 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
534 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
535
536 #undef DEFINE_GETSETOOP_VOLATILE
537
538 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
539 OrderAccess::fence();
540 } UNSAFE_END
541
542 ////// Allocation requests
543
544 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
545 JvmtiVMObjectAllocEventCollector oam;
546 instanceOop i = InstanceKlass::allocate_instance(JNIHandles::resolve_non_null(cls), CHECK_NULL);
547 return JNIHandles::make_local(THREAD, i);
548 } UNSAFE_END
549
550 UNSAFE_LEAF(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
551 size_t sz = (size_t)size;
552
553 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
554
555 void* x = os::malloc(sz, mtOther);
556
557 return addr_to_java(x);
558 } UNSAFE_END
559
560 UNSAFE_LEAF(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
561 void* p = addr_from_java(addr);
562 size_t sz = (size_t)size;
563
564 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
565
566 void* x = os::realloc(p, sz, mtOther);
567
568 return addr_to_java(x);
569 } UNSAFE_END
570
571 UNSAFE_LEAF(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
572 void* p = addr_from_java(addr);
573
574 os::free(p);
575 } UNSAFE_END
576
577 UNSAFE_ENTRY_SCOPED(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
578 size_t sz = (size_t)size;
579
580 oop base = JNIHandles::resolve(obj);
581 void* p = index_oop_from_field_offset_long(base, offset);
582
583 {
584 GuardUnsafeAccess guard(thread);
585 if (StubRoutines::unsafe_setmemory() != nullptr) {
586 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread));
587 StubRoutines::UnsafeSetMemory_stub()(p, sz, value);
588 } else {
589 Copy::fill_to_memory_atomic(p, sz, value);
590 }
591 }
592 } UNSAFE_END
593
594 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
595 size_t sz = (size_t)size;
596
597 oop srcp = JNIHandles::resolve(srcObj);
598 oop dstp = JNIHandles::resolve(dstObj);
599
600 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
601 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
602 {
603 GuardUnsafeAccess guard(thread);
604 if (StubRoutines::unsafe_arraycopy() != nullptr) {
605 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread));
606 StubRoutines::UnsafeArrayCopy_stub()(src, dst, sz);
607 } else {
608 Copy::conjoint_memory_atomic(src, dst, sz);
609 }
610 }
611 } UNSAFE_END
612
613 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
614 size_t sz = (size_t)size;
615 size_t esz = (size_t)elemSize;
616
617 oop srcp = JNIHandles::resolve(srcObj);
618 oop dstp = JNIHandles::resolve(dstObj);
619
620 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
621 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
622
623 {
624 GuardUnsafeAccess guard(thread);
625 Copy::conjoint_swap(src, dst, sz, esz);
626 }
627 } UNSAFE_END
628
629 UNSAFE_LEAF (void, Unsafe_WriteBack0(JNIEnv *env, jobject unsafe, jlong line)) {
630 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
631 #ifdef ASSERT
632 if (TraceMemoryWriteback) {
633 tty->print_cr("Unsafe: writeback 0x%p", addr_from_java(line));
634 }
635 #endif
636
637 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current()));
638 assert(StubRoutines::data_cache_writeback() != nullptr, "sanity");
639 (StubRoutines::DataCacheWriteback_stub())(addr_from_java(line));
640 } UNSAFE_END
641
642 static void doWriteBackSync0(bool is_pre)
643 {
644 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current()));
645 assert(StubRoutines::data_cache_writeback_sync() != nullptr, "sanity");
646 (StubRoutines::DataCacheWritebackSync_stub())(is_pre);
647 }
648
649 UNSAFE_LEAF (void, Unsafe_WriteBackPreSync0(JNIEnv *env, jobject unsafe)) {
650 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
651 #ifdef ASSERT
652 if (TraceMemoryWriteback) {
653 tty->print_cr("Unsafe: writeback pre-sync");
654 }
655 #endif
656
657 doWriteBackSync0(true);
658 } UNSAFE_END
659
660 UNSAFE_LEAF (void, Unsafe_WriteBackPostSync0(JNIEnv *env, jobject unsafe)) {
661 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
662 #ifdef ASSERT
663 if (TraceMemoryWriteback) {
664 tty->print_cr("Unsafe: writeback pre-sync");
665 }
666 #endif
667
668 doWriteBackSync0(false);
669 } UNSAFE_END
670
671 ////// Random queries
672
673 // Finds the object field offset of a field with the matching name, or an error code
674 // Error code -1 is not found, -2 is static field
675 static jlong find_known_instance_field_offset(jclass clazz, jstring name, TRAPS) {
676 assert(clazz != nullptr, "clazz must not be null");
677 assert(name != nullptr, "name must not be null");
678
679 ResourceMark rm(THREAD);
680 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
681
682 InstanceKlass* k = java_lang_Class::as_InstanceKlass(JNIHandles::resolve_non_null(clazz));
683
684 jint offset = -1; // Not found
685 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
686 Symbol *name = fs.name();
687 if (name->equals(utf_name)) {
688 if (!fs.access_flags().is_static()) {
689 offset = fs.offset();
690 } else {
691 offset = -2; // A static field
692 }
693 break;
694 }
695 }
696 if (offset < 0) {
697 return offset; // Error code
698 }
699 return field_offset_from_byte_offset(offset);
700 }
701
702 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
703 assert(field != nullptr, "field must not be null");
704
705 oop reflected = JNIHandles::resolve_non_null(field);
706 oop mirror = java_lang_reflect_Field::clazz(reflected);
707 Klass* k = java_lang_Class::as_Klass(mirror);
708 int slot = java_lang_reflect_Field::slot(reflected);
709 int modifiers = java_lang_reflect_Field::modifiers(reflected);
710
711 if (must_be_static >= 0) {
712 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
713 if (must_be_static != really_is_static) {
714 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
715 }
716 }
717
718 int offset = InstanceKlass::cast(k)->field_offset(slot);
719 return field_offset_from_byte_offset(offset);
720 }
721
722 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
723 return find_field_offset(field, 0, THREAD);
724 } UNSAFE_END
725
726 UNSAFE_ENTRY(jlong, Unsafe_KnownObjectFieldOffset0(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
727 return find_known_instance_field_offset(c, name, THREAD);
728 } UNSAFE_END
729
730 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
731 return find_field_offset(field, 1, THREAD);
732 } UNSAFE_END
733
734 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
735 assert(field != nullptr, "field must not be null");
736
737 // Note: In this VM implementation, a field address is always a short
738 // offset from the base of a klass metaobject. Thus, the full dynamic
739 // range of the return type is never used. However, some implementations
740 // might put the static field inside an array shared by many classes,
741 // or even at a fixed address, in which case the address could be quite
742 // large. In that last case, this function would return null, since
743 // the address would operate alone, without any base pointer.
744
745 oop reflected = JNIHandles::resolve_non_null(field);
746 oop mirror = java_lang_reflect_Field::clazz(reflected);
747 int modifiers = java_lang_reflect_Field::modifiers(reflected);
748
749 if ((modifiers & JVM_ACC_STATIC) == 0) {
750 THROW_NULL(vmSymbols::java_lang_IllegalArgumentException());
751 }
752
753 return JNIHandles::make_local(THREAD, mirror);
754 } UNSAFE_END
755
756 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
757 assert(clazz != nullptr, "clazz must not be null");
758
759 oop mirror = JNIHandles::resolve_non_null(clazz);
760
761 Klass* klass = java_lang_Class::as_Klass(mirror);
762 if (klass != nullptr && klass->should_be_initialized()) {
763 InstanceKlass* k = InstanceKlass::cast(klass);
764 k->initialize(CHECK);
765 }
766 }
767 UNSAFE_END
768
769 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
770 assert(clazz != nullptr, "clazz must not be null");
771
772 oop mirror = JNIHandles::resolve_non_null(clazz);
773 Klass* klass = java_lang_Class::as_Klass(mirror);
774
775 if (klass != nullptr && klass->should_be_initialized()) {
776 return true;
777 }
778
779 return false;
780 }
781 UNSAFE_END
782
783 UNSAFE_ENTRY(void, Unsafe_NotifyStrictStaticAccess0(JNIEnv *env, jobject unsafe, jobject clazz,
784 jlong sfoffset, jboolean writing)) {
785 assert(clazz != nullptr, "clazz must not be null");
786
787 oop mirror = JNIHandles::resolve_non_null(clazz);
788 Klass* klass = java_lang_Class::as_Klass(mirror);
789
790 if (klass != nullptr && klass->is_instance_klass()) {
791 InstanceKlass* ik = InstanceKlass::cast(klass);
792 fieldDescriptor fd;
793 if (ik->find_local_field_from_offset((int)sfoffset, true, &fd)) {
794 // Note: The Unsafe API takes an OFFSET, but the InstanceKlass wants the INDEX.
795 // We could surface field indexes into Unsafe, but that's too much churn.
796 ik->notify_strict_static_access(fd.index(), writing, CHECK);
797 return;
798 }
799 }
800 THROW(vmSymbols::java_lang_InternalError());
801 }
802 UNSAFE_END
803
804 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
805 assert(clazz != nullptr, "clazz must not be null");
806
807 oop mirror = JNIHandles::resolve_non_null(clazz);
808 Klass* k = java_lang_Class::as_Klass(mirror);
809
810 if (k == nullptr || !k->is_array_klass()) {
811 THROW(vmSymbols::java_lang_InvalidClassException());
812 } else if (k->is_typeArray_klass()) {
813 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
814 base = tak->array_header_in_bytes();
815 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
816 scale = (1 << tak->log2_element_size());
817 } else if (k->is_objArray_klass()) {
818 Klass* ek = ObjArrayKlass::cast(k)->element_klass();
819 if (!ek->is_identity_class() && !ek->is_abstract()) {
820 // Arrays of a concrete value class type can have multiple layouts
821 // There's no good value to return, so throwing an exception is the way out
822 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), "Arrays of a concrete value class don't have a single base and offset");
823 }
824 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
825 scale = heapOopSize;
826 } else {
827 ShouldNotReachHere();
828 }
829 }
830
831 UNSAFE_ENTRY(jint, Unsafe_ArrayInstanceBaseOffset0(JNIEnv *env, jobject unsafe, jarray array)) {
832 assert(array != nullptr, "array must not be null");
833 oop ar = JNIHandles::resolve_non_null(array);
834 assert(ar->is_array(), "Must be an array");
835 ArrayKlass* ak = ArrayKlass::cast(ar->klass());
836 if (ak->is_refArray_klass()) {
837 return arrayOopDesc::base_offset_in_bytes(T_OBJECT);
838 } else if (ak->is_flatArray_klass()) {
839 FlatArrayKlass* fak = FlatArrayKlass::cast(ak);
840 return fak->array_header_in_bytes();
841 } else {
842 ShouldNotReachHere();
843 }
844 } UNSAFE_END
845
846 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
847 int base = 0, scale = 0;
848 getBaseAndScale(base, scale, clazz, CHECK_0);
849
850 return field_offset_from_byte_offset(base);
851 } UNSAFE_END
852
853
854 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
855 int base = 0, scale = 0;
856 getBaseAndScale(base, scale, clazz, CHECK_0);
857
858 // This VM packs both fields and array elements down to the byte.
859 // But watch out: If this changes, so that array references for
860 // a given primitive type (say, T_BOOLEAN) use different memory units
861 // than fields, this method MUST return zero for such arrays.
862 // For example, the VM used to store sub-word sized fields in full
863 // words in the object layout, so that accessors like getByte(Object,int)
864 // did not really do what one might expect for arrays. Therefore,
865 // this function used to report a zero scale factor, so that the user
866 // would know not to attempt to access sub-word array elements.
867 // // Code for unpacked fields:
868 // if (scale < wordSize) return 0;
869
870 // The following allows for a pretty general fieldOffset cookie scheme,
871 // but requires it to be linear in byte offset.
872 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
873 } UNSAFE_END
874
875 UNSAFE_ENTRY(jint, Unsafe_ArrayInstanceIndexScale0(JNIEnv *env, jobject unsafe, jarray array)) {
876 assert(array != nullptr, "array must not be null");
877 oop ar = JNIHandles::resolve_non_null(array);
878 assert(ar->is_array(), "Must be an array");
879 ArrayKlass* ak = ArrayKlass::cast(ar->klass());
880 if (ak->is_refArray_klass()) {
881 return heapOopSize;
882 } else if (ak->is_flatArray_klass()) {
883 FlatArrayKlass* fak = FlatArrayKlass::cast(ak);
884 return fak->element_byte_size();
885 } else {
886 ShouldNotReachHere();
887 }
888 } UNSAFE_END
889
890 UNSAFE_ENTRY(jarray, Unsafe_GetFieldMap0(JNIEnv* env, jobject unsafe, jclass clazz)) {
891 oop mirror = JNIHandles::resolve_non_null(clazz);
892 Klass* k = java_lang_Class::as_Klass(mirror);
893
894 if (!k->is_inline_klass()) {
895 THROW_MSG_NULL(vmSymbols::java_lang_IllegalArgumentException(), "Argument is not a concrete value class");
896 }
897 InlineKlass* vk = InlineKlass::cast(k);
898 oop map = mirror->obj_field(vk->acmp_maps_offset());
899 return (jarray) JNIHandles::make_local(THREAD, map);
900 } UNSAFE_END
901
902
903 UNSAFE_ENTRY(jlong, Unsafe_GetObjectSize0(JNIEnv* env, jobject o, jobject obj))
904 oop p = JNIHandles::resolve(obj);
905 return p->size() * HeapWordSize;
906 UNSAFE_END
907
908
909 static inline void throw_new(JNIEnv *env, const char *ename) {
910 jclass cls = env->FindClass(ename);
911 if (env->ExceptionCheck()) {
912 env->ExceptionClear();
913 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
914 return;
915 }
916
917 env->ThrowNew(cls, nullptr);
918 }
919
920 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
921 // Code lifted from JDK 1.3 ClassLoader.c
922
923 jbyte *body;
924 char *utfName = nullptr;
925 jclass result = nullptr;
926 char buf[128];
927
928 assert(data != nullptr, "Class bytes must not be null");
929 assert(length >= 0, "length must not be negative: %d", length);
930
931 if (UsePerfData) {
932 ClassLoader::unsafe_defineClassCallCounter()->inc();
933 }
934
935 body = NEW_C_HEAP_ARRAY_RETURN_NULL(jbyte, length, mtInternal);
936 if (body == nullptr) {
937 throw_new(env, "java/lang/OutOfMemoryError");
938 return nullptr;
939 }
940
941 env->GetByteArrayRegion(data, offset, length, body);
942 if (env->ExceptionCheck()) {
943 goto free_body;
944 }
945
946 if (name != nullptr) {
947 uint len = env->GetStringUTFLength(name);
948 int unicode_len = env->GetStringLength(name);
949
950 if (len >= sizeof(buf)) {
951 utfName = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len + 1, mtInternal);
952 if (utfName == nullptr) {
953 throw_new(env, "java/lang/OutOfMemoryError");
954 goto free_body;
955 }
956 } else {
957 utfName = buf;
958 }
959
960 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
961
962 for (uint i = 0; i < len; i++) {
963 if (utfName[i] == '.') utfName[i] = '/';
964 }
965 }
966
967 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
968
969 if (utfName && utfName != buf) {
970 FREE_C_HEAP_ARRAY(char, utfName);
971 }
972
973 free_body:
974 FREE_C_HEAP_ARRAY(jbyte, body);
975 return result;
976 }
977
978
979 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
980 ThreadToNativeFromVM ttnfv(thread);
981
982 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
983 } UNSAFE_END
984
985
986 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
987 ThreadToNativeFromVM ttnfv(thread);
988 env->Throw(thr);
989 } UNSAFE_END
990
991 // JSR166 ------------------------------------------------------------------
992
993 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
994 oop x = JNIHandles::resolve(x_h);
995 oop e = JNIHandles::resolve(e_h);
996 oop p = JNIHandles::resolve(obj);
997 assert_field_offset_sane(p, offset);
998 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
999 return JNIHandles::make_local(THREAD, res);
1000 } UNSAFE_END
1001
1002 UNSAFE_ENTRY_SCOPED(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1003 oop p = JNIHandles::resolve(obj);
1004 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1005 return AtomicAccess::cmpxchg(addr, e, x);
1006 } UNSAFE_END
1007
1008 UNSAFE_ENTRY_SCOPED(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1009 oop p = JNIHandles::resolve(obj);
1010 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1011 return AtomicAccess::cmpxchg(addr, e, x);
1012 } UNSAFE_END
1013
1014 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1015 oop x = JNIHandles::resolve(x_h);
1016 oop e = JNIHandles::resolve(e_h);
1017 oop p = JNIHandles::resolve(obj);
1018 assert_field_offset_sane(p, offset);
1019 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
1020 return ret == e;
1021 } UNSAFE_END
1022
1023 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1024 oop p = JNIHandles::resolve(obj);
1025 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1026 return AtomicAccess::cmpxchg(addr, e, x) == e;
1027 } UNSAFE_END
1028
1029 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1030 oop p = JNIHandles::resolve(obj);
1031 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1032 return AtomicAccess::cmpxchg(addr, e, x) == e;
1033 } UNSAFE_END
1034
1035 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) {
1036 assert(event != nullptr, "invariant");
1037 event->set_parkedClass((obj != nullptr) ? obj->klass() : nullptr);
1038 event->set_timeout(timeout_nanos);
1039 event->set_until(until_epoch_millis);
1040 event->set_address((obj != nullptr) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1041 event->commit();
1042 }
1043
1044 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1045 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1046 EventThreadPark event;
1047
1048 JavaThreadParkedState jtps(thread, time != 0);
1049 thread->parker()->park(isAbsolute != 0, time);
1050 if (event.should_commit()) {
1051 const oop obj = thread->current_park_blocker();
1052 if (time == 0) {
1053 post_thread_park_event(&event, obj, min_jlong, min_jlong);
1054 } else {
1055 if (isAbsolute != 0) {
1056 post_thread_park_event(&event, obj, min_jlong, time);
1057 } else {
1058 post_thread_park_event(&event, obj, time, min_jlong);
1059 }
1060 }
1061 }
1062 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1063 } UNSAFE_END
1064
1065 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1066 if (jthread != nullptr) {
1067 oop thread_oop = JNIHandles::resolve_non_null(jthread);
1068 // Get the JavaThread* stored in the java.lang.Thread object _before_
1069 // the embedded ThreadsListHandle is constructed so we know if the
1070 // early life stage of the JavaThread* is protected. We use acquire
1071 // here to ensure that if we see a non-nullptr value, then we also
1072 // see the main ThreadsList updates from the JavaThread* being added.
1073 FastThreadsListHandle ftlh(thread_oop, java_lang_Thread::thread_acquire(thread_oop));
1074 JavaThread* thr = ftlh.protected_java_thread();
1075 if (thr != nullptr) {
1076 // The still live JavaThread* is protected by the FastThreadsListHandle
1077 // so it is safe to access.
1078 Parker* p = thr->parker();
1079 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1080 p->unpark();
1081 }
1082 } // FastThreadsListHandle is destroyed here.
1083 } UNSAFE_END
1084
1085 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1086 const int max_nelem = 3;
1087 double la[max_nelem];
1088 jint ret;
1089
1090 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1091 assert(a->is_typeArray(), "must be type array");
1092
1093 ret = os::loadavg(la, nelem);
1094 if (ret == -1) {
1095 return -1;
1096 }
1097
1098 // if successful, ret is the number of samples actually retrieved.
1099 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1100 switch(ret) {
1101 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1102 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1103 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1104 }
1105
1106 return ret;
1107 } UNSAFE_END
1108
1109
1110 /// JVM_RegisterUnsafeMethods
1111
1112 #define ADR "J"
1113
1114 #define LANG "Ljava/lang/"
1115
1116 #define OBJ LANG "Object;"
1117 #define CLS LANG "Class;"
1118 #define FLD LANG "reflect/Field;"
1119 #define THR LANG "Throwable;"
1120
1121 #define OBJ_ARR "[" OBJ
1122
1123 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1124 #define DAC_Args CLS "[B[" OBJ
1125
1126 #define CC (char*) /*cast a literal from (const char*)*/
1127 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1128
1129 #define DECLARE_GETPUTOOP(Type, Desc) \
1130 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1131 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1132 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1133 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1134
1135
1136 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1137 {CC "getReference", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetReference)},
1138 {CC "putReference", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReference)},
1139 {CC "getReferenceVolatile", CC "(" OBJ "J)" OBJ, FN_PTR(Unsafe_GetReferenceVolatile)},
1140 {CC "putReferenceVolatile", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReferenceVolatile)},
1141
1142 {CC "isFlatField0", CC "(" OBJ ")Z", FN_PTR(Unsafe_IsFlatField)},
1143 {CC "hasNullMarker0", CC "(" OBJ ")Z", FN_PTR(Unsafe_HasNullMarker)},
1144 {CC "nullMarkerOffset0", CC "(" OBJ ")I", FN_PTR(Unsafe_NullMarkerOffset)},
1145 {CC "arrayLayout0", CC "(" OBJ_ARR ")I", FN_PTR(Unsafe_ArrayLayout)},
1146 {CC "fieldLayout0", CC "(" OBJ ")I", FN_PTR(Unsafe_FieldLayout)},
1147 {CC "newSpecialArray", CC "(" CLS "II)[" OBJ, FN_PTR(Unsafe_NewSpecialArray)},
1148 {CC "getFlatValue", CC "(" OBJ "JI" CLS ")" OBJ, FN_PTR(Unsafe_GetFlatValue)},
1149 {CC "putFlatValue", CC "(" OBJ "JI" CLS OBJ ")V", FN_PTR(Unsafe_PutFlatValue)},
1150 {CC "valueHeaderSize", CC "(" CLS ")J", FN_PTR(Unsafe_ValueHeaderSize)},
1151
1152 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1153
1154 DECLARE_GETPUTOOP(Boolean, Z),
1155 DECLARE_GETPUTOOP(Byte, B),
1156 DECLARE_GETPUTOOP(Short, S),
1157 DECLARE_GETPUTOOP(Char, C),
1158 DECLARE_GETPUTOOP(Int, I),
1159 DECLARE_GETPUTOOP(Long, J),
1160 DECLARE_GETPUTOOP(Float, F),
1161 DECLARE_GETPUTOOP(Double, D),
1162
1163 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1164 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1165 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1166
1167 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1168 {CC "knownObjectFieldOffset0", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_KnownObjectFieldOffset0)},
1169 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1170 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1171 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1172 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1173 {CC "arrayInstanceBaseOffset0", CC "(" OBJ_ARR ")I", FN_PTR(Unsafe_ArrayInstanceBaseOffset0)},
1174 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1175 {CC "arrayInstanceIndexScale0", CC "(" OBJ_ARR ")I", FN_PTR(Unsafe_ArrayInstanceIndexScale0)},
1176 {CC "getFieldMap0", CC "(Ljava/lang/Class;)[I", FN_PTR(Unsafe_GetFieldMap0)},
1177 {CC "getObjectSize0", CC "(Ljava/lang/Object;)J", FN_PTR(Unsafe_GetObjectSize0)},
1178
1179 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1180 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1181 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1182 {CC "compareAndSetReference",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetReference)},
1183 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1184 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1185 {CC "compareAndExchangeReference", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeReference)},
1186 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1187 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1188
1189 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1190 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1191
1192 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1193
1194 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1195 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1196 {CC "writeback0", CC "(" "J" ")V", FN_PTR(Unsafe_WriteBack0)},
1197 {CC "writebackPreSync0", CC "()V", FN_PTR(Unsafe_WriteBackPreSync0)},
1198 {CC "writebackPostSync0", CC "()V", FN_PTR(Unsafe_WriteBackPostSync0)},
1199 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1200
1201 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1202 {CC "notifyStrictStaticAccess0", CC "(" CLS "JZ)V", FN_PTR(Unsafe_NotifyStrictStaticAccess0)},
1203
1204 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1205 };
1206
1207 #undef CC
1208 #undef FN_PTR
1209
1210 #undef ADR
1211 #undef LANG
1212 #undef OBJ
1213 #undef CLS
1214 #undef FLD
1215 #undef THR
1216 #undef DC_Args
1217 #undef DAC_Args
1218
1219 #undef DECLARE_GETPUTOOP
1220
1221
1222 // This function is exported, used by NativeLookup.
1223 // The Unsafe_xxx functions above are called only from the interpreter.
1224 // The optimizer looks at names and signatures to recognize
1225 // individual functions.
1226
1227 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1228 ThreadToNativeFromVM ttnfv(thread);
1229
1230 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1231 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1232 } JVM_END