1 /*
2 * Copyright (c) 2000, 2019, 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 "precompiled.hpp"
26 #include "jni.h"
27 #include "jvm.h"
28 #include "classfile/classFileStream.hpp"
29 #include "classfile/classLoader.hpp"
30 #include "classfile/vmSymbols.hpp"
31 #include "jfr/jfrEvents.hpp"
32 #include "memory/allocation.inline.hpp"
33 #include "memory/resourceArea.hpp"
34 #include "logging/log.hpp"
35 #include "logging/logStream.hpp"
36 #include "oops/access.inline.hpp"
37 #include "oops/fieldStreams.hpp"
38 #include "oops/objArrayOop.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "oops/typeArrayOop.inline.hpp"
41 #include "oops/valueArrayKlass.hpp"
42 #include "oops/valueArrayOop.hpp"
43 #include "oops/valueArrayOop.inline.hpp"
44 #include "prims/unsafe.hpp"
45 #include "runtime/atomic.hpp"
46 #include "runtime/fieldDescriptor.inline.hpp"
47 #include "runtime/globals.hpp"
48 #include "runtime/handles.inline.hpp"
49 #include "runtime/interfaceSupport.inline.hpp"
50 #include "runtime/jniHandles.inline.hpp"
51 #include "runtime/orderAccess.hpp"
52 #include "runtime/reflection.hpp"
53 #include "runtime/sharedRuntime.hpp"
54 #include "runtime/thread.hpp"
55 #include "runtime/threadSMR.hpp"
56 #include "runtime/vm_version.hpp"
57 #include "services/threadService.hpp"
58 #include "utilities/align.hpp"
59 #include "utilities/copy.hpp"
60 #include "utilities/dtrace.hpp"
61 #include "utilities/macros.hpp"
62
63 /**
64 * Implementation of the jdk.internal.misc.Unsafe class
65 */
66
67
68 #define MAX_OBJECT_SIZE \
69 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
70 + ((julong)max_jint * sizeof(double)) )
71
72
73 #define UNSAFE_ENTRY(result_type, header) \
74 JVM_ENTRY(static result_type, header)
75
76 #define UNSAFE_LEAF(result_type, header) \
77 JVM_LEAF(static result_type, header)
78
79 #define UNSAFE_END JVM_END
80
81
82 static inline void* addr_from_java(jlong addr) {
83 // This assert fails in a variety of ways on 32-bit systems.
84 // It is impossible to predict whether native code that converts
85 // pointers to longs will sign-extend or zero-extend the addresses.
86 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
87 return (void*)(uintptr_t)addr;
88 }
89
90 static inline jlong addr_to_java(void* p) {
91 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
92 return (uintptr_t)p;
93 }
94
95
96 // Note: The VM's obj_field and related accessors use byte-scaled
97 // ("unscaled") offsets, just as the unsafe methods do.
98
99 // However, the method Unsafe.fieldOffset explicitly declines to
100 // guarantee this. The field offset values manipulated by the Java user
101 // through the Unsafe API are opaque cookies that just happen to be byte
102 // offsets. We represent this state of affairs by passing the cookies
103 // through conversion functions when going between the VM and the Unsafe API.
104 // The conversion functions just happen to be no-ops at present.
105
106 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
107 return field_offset;
108 }
109
110 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
111 return byte_offset;
112 }
113
114 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
115 #ifdef ASSERT
116 jlong byte_offset = field_offset_to_byte_offset(field_offset);
117
118 if (p != NULL) {
119 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
120 if (byte_offset == (jint)byte_offset) {
121 void* ptr_plus_disp = (address)p + byte_offset;
122 assert(p->field_addr_raw((jint)byte_offset) == ptr_plus_disp,
123 "raw [ptr+disp] must be consistent with oop::field_addr_raw");
124 }
125 jlong p_size = HeapWordSize * (jlong)(p->size());
126 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
127 }
128 #endif
129 }
130
131 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
132 assert_field_offset_sane(p, field_offset);
133 jlong byte_offset = field_offset_to_byte_offset(field_offset);
134
135 if (p != NULL) {
136 p = Access<>::resolve(p);
137 }
138
139 if (sizeof(char*) == sizeof(jint)) { // (this constant folds!)
140 return (address)p + (jint) byte_offset;
141 } else {
142 return (address)p + byte_offset;
143 }
144 }
145
146 // Externally callable versions:
147 // (Use these in compiler intrinsics which emulate unsafe primitives.)
148 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
149 return field_offset;
150 }
151 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
152 return byte_offset;
153 }
154
155 ///// Data read/writes on the Java heap and in native (off-heap) memory
156
157 /**
158 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
159 */
160 class GuardUnsafeAccess {
161 JavaThread* _thread;
162
163 public:
164 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
165 // native/off-heap access which may raise SIGBUS if accessing
166 // memory mapped file data in a region of the file which has
167 // been truncated and is now invalid.
168 _thread->set_doing_unsafe_access(true);
169 }
170
171 ~GuardUnsafeAccess() {
172 _thread->set_doing_unsafe_access(false);
173 }
174 };
175
176 /**
177 * Helper class for accessing memory.
178 *
179 * Normalizes values and wraps accesses in
180 * JavaThread::doing_unsafe_access() if needed.
181 */
182 template <typename T>
183 class MemoryAccess : StackObj {
184 JavaThread* _thread;
185 oop _obj;
186 ptrdiff_t _offset;
187
188 // Resolves and returns the address of the memory access.
189 // This raw memory access may fault, so we make sure it happens within the
190 // guarded scope by making the access volatile at least. Since the store
191 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
192 // can not be reordered by the compiler. Therefore, if the access triggers
193 // a fault, we will know that Thread::doing_unsafe_access() returns true.
194 volatile T* addr() {
195 void* addr = index_oop_from_field_offset_long(_obj, _offset);
196 return static_cast<volatile T*>(addr);
197 }
198
199 template <typename U>
200 U normalize_for_write(U x) {
201 return x;
202 }
203
204 jboolean normalize_for_write(jboolean x) {
205 return x & 1;
206 }
207
208 template <typename U>
209 U normalize_for_read(U x) {
210 return x;
211 }
212
213 jboolean normalize_for_read(jboolean x) {
214 return x != 0;
215 }
216
217 public:
218 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
219 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
220 assert_field_offset_sane(_obj, offset);
221 }
222
223 T get() {
224 if (_obj == NULL) {
225 GuardUnsafeAccess guard(_thread);
226 T ret = RawAccess<>::load(addr());
227 return normalize_for_read(ret);
228 } else {
229 T ret = HeapAccess<>::load_at(_obj, _offset);
230 return normalize_for_read(ret);
231 }
232 }
233
234 void put(T x) {
235 if (_obj == NULL) {
236 GuardUnsafeAccess guard(_thread);
237 RawAccess<>::store(addr(), normalize_for_write(x));
238 } else {
239 assert(!_obj->is_value() || _obj->mark().is_larval_state(), "must be an object instance or a larval value");
240 HeapAccess<>::store_at(_obj, _offset, normalize_for_write(x));
241 }
242 }
243
244 T get_volatile() {
245 if (_obj == NULL) {
246 GuardUnsafeAccess guard(_thread);
247 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
248 return normalize_for_read(ret);
249 } else {
250 T ret = HeapAccess<MO_SEQ_CST>::load_at(_obj, _offset);
251 return normalize_for_read(ret);
252 }
253 }
254
255 void put_volatile(T x) {
256 if (_obj == NULL) {
257 GuardUnsafeAccess guard(_thread);
258 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
259 } else {
260 HeapAccess<MO_SEQ_CST>::store_at(_obj, _offset, normalize_for_write(x));
261 }
262 }
263 };
264
265 #ifdef ASSERT
266 /*
267 * Get the field descriptor of the field of the given object at the given offset.
268 */
269 static bool get_field_descriptor(oop p, jlong offset, fieldDescriptor* fd) {
270 bool found = false;
271 Klass* k = p->klass();
272 if (k->is_instance_klass()) {
273 InstanceKlass* ik = InstanceKlass::cast(k);
274 found = ik->find_field_from_offset((int)offset, false, fd);
275 if (!found && ik->is_mirror_instance_klass()) {
276 Klass* k2 = java_lang_Class::as_Klass(p);
277 if (k2->is_instance_klass()) {
278 ik = InstanceKlass::cast(k2);
279 found = ik->find_field_from_offset((int)offset, true, fd);
280 }
281 }
282 }
283 return found;
284 }
285 #endif // ASSERT
286
287 static void assert_and_log_unsafe_value_access(oop p, jlong offset, ValueKlass* vk) {
288 Klass* k = p->klass();
289 #ifdef ASSERT
290 if (k->is_instance_klass()) {
291 assert_field_offset_sane(p, offset);
292 fieldDescriptor fd;
293 bool found = get_field_descriptor(p, offset, &fd);
294 if (found) {
295 assert(found, "value field not found");
296 assert(fd.is_flattened(), "field not flat");
297 } else {
298 if (log_is_enabled(Trace, valuetypes)) {
299 log_trace(valuetypes)("not a field in %s at offset " SIZE_FORMAT_HEX,
300 p->klass()->external_name(), offset);
301 }
302 }
303 } else if (k->is_valueArray_klass()) {
304 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
305 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
306 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
307 assert(dest == ((address)p) + offset, "invalid offset");
308 } else {
309 ShouldNotReachHere();
310 }
311 #endif // ASSERT
312 if (log_is_enabled(Trace, valuetypes)) {
313 if (k->is_valueArray_klass()) {
314 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
315 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size();
316 address dest = (address)((valueArrayOop)p)->value_at_addr(index, vak->layout_helper());
317 log_trace(valuetypes)("%s array type %s index %d element size %d offset " SIZE_FORMAT_HEX " at " INTPTR_FORMAT,
318 p->klass()->external_name(), vak->external_name(),
319 index, vak->element_byte_size(), offset, p2i(dest));
320 } else {
321 log_trace(valuetypes)("%s field type %s at offset " SIZE_FORMAT_HEX,
322 p->klass()->external_name(), vk->external_name(), offset);
323 }
324 }
325 }
326
327 // These functions allow a null base pointer with an arbitrary address.
328 // But if the base pointer is non-null, the offset should make some sense.
329 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
330 UNSAFE_ENTRY(jobject, Unsafe_GetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
331 oop p = JNIHandles::resolve(obj);
332 assert_field_offset_sane(p, offset);
333 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
334 return JNIHandles::make_local(env, v);
335 } UNSAFE_END
336
337 UNSAFE_ENTRY(void, Unsafe_PutReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
338 oop x = JNIHandles::resolve(x_h);
339 oop p = JNIHandles::resolve(obj);
340 assert_field_offset_sane(p, offset);
341 assert(!p->is_value() || p->mark().is_larval_state(), "must be an object instance or a larval value");
342 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
343 } UNSAFE_END
344
345 UNSAFE_ENTRY(jlong, Unsafe_ValueHeaderSize(JNIEnv *env, jobject unsafe, jclass c)) {
346 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
347 ValueKlass* vk = ValueKlass::cast(k);
348 return vk->first_field_offset();
349 } UNSAFE_END
350
351 UNSAFE_ENTRY(jboolean, Unsafe_IsFlattenedArray(JNIEnv *env, jobject unsafe, jclass c)) {
352 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c));
353 return k->is_valueArray_klass();
354 } UNSAFE_END
355
356 UNSAFE_ENTRY(jobject, Unsafe_UninitializedDefaultValue(JNIEnv *env, jobject unsafe, jclass vc)) {
357 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
358 ValueKlass* vk = ValueKlass::cast(k);
359 oop v = vk->default_value();
360 return JNIHandles::make_local(env, v);
361 } UNSAFE_END
362
363 UNSAFE_ENTRY(jobject, Unsafe_GetValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc)) {
364 oop base = JNIHandles::resolve(obj);
365 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
366 ValueKlass* vk = ValueKlass::cast(k);
367 assert_and_log_unsafe_value_access(base, offset, vk);
368 Handle base_h(THREAD, base);
369 oop v = vk->allocate_instance(CHECK_NULL); // allocate instance
370 vk->initialize(CHECK_NULL); // If field is a default value, value class might not be initialized yet
371 vk->value_store(((address)(oopDesc*)base_h()) + offset,
372 vk->data_for_oop(v),
373 true, true);
374 return JNIHandles::make_local(env, v);
375 } UNSAFE_END
376
377 UNSAFE_ENTRY(void, Unsafe_PutValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc, jobject value)) {
378 oop base = JNIHandles::resolve(obj);
379 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc));
380 ValueKlass* vk = ValueKlass::cast(k);
381 assert(!base->is_value() || base->mark().is_larval_state(), "must be an object instance or a larval value");
382 assert_and_log_unsafe_value_access(base, offset, vk);
383 oop v = JNIHandles::resolve(value);
384 vk->value_store(vk->data_for_oop(v),
385 ((address)(oopDesc*)base) + offset, true, true);
386 } UNSAFE_END
387
388 UNSAFE_ENTRY(jobject, Unsafe_MakePrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) {
389 oop v = JNIHandles::resolve_non_null(value);
390 assert(v->is_value(), "must be a value instance");
391 Handle vh(THREAD, v);
392 ValueKlass* vk = ValueKlass::cast(v->klass());
393 instanceOop new_value = vk->allocate_instance(CHECK_NULL);
394 vk->value_store(vk->data_for_oop(vh()), vk->data_for_oop(new_value), true, false);
395 markWord mark = new_value->mark();
396 new_value->set_mark(mark.enter_larval_state());
397 return JNIHandles::make_local(env, new_value);
398 } UNSAFE_END
399
400 UNSAFE_ENTRY(jobject, Unsafe_FinishPrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) {
401 oop v = JNIHandles::resolve(value);
402 assert(v->mark().is_larval_state(), "must be a larval value");
403 markWord mark = v->mark();
404 v->set_mark(mark.exit_larval_state());
405 return JNIHandles::make_local(env, v);
406 } UNSAFE_END
407
408 UNSAFE_ENTRY(jobject, Unsafe_GetReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
409 oop p = JNIHandles::resolve(obj);
410 assert_field_offset_sane(p, offset);
411 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
412 return JNIHandles::make_local(env, v);
413 } UNSAFE_END
414
415 UNSAFE_ENTRY(void, Unsafe_PutReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
416 oop x = JNIHandles::resolve(x_h);
417 oop p = JNIHandles::resolve(obj);
418 assert_field_offset_sane(p, offset);
419 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
420 } UNSAFE_END
421
422 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
423 oop v = *(oop*) (address) addr;
424 return JNIHandles::make_local(env, v);
425 } UNSAFE_END
426
427 #define DEFINE_GETSETOOP(java_type, Type) \
428 \
429 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
430 return MemoryAccess<java_type>(thread, obj, offset).get(); \
431 } UNSAFE_END \
432 \
433 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
434 MemoryAccess<java_type>(thread, obj, offset).put(x); \
435 } UNSAFE_END \
436 \
437 // END DEFINE_GETSETOOP.
438
439 DEFINE_GETSETOOP(jboolean, Boolean)
440 DEFINE_GETSETOOP(jbyte, Byte)
441 DEFINE_GETSETOOP(jshort, Short);
442 DEFINE_GETSETOOP(jchar, Char);
443 DEFINE_GETSETOOP(jint, Int);
444 DEFINE_GETSETOOP(jlong, Long);
445 DEFINE_GETSETOOP(jfloat, Float);
446 DEFINE_GETSETOOP(jdouble, Double);
447
448 #undef DEFINE_GETSETOOP
449
450 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
451 \
452 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
453 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
454 } UNSAFE_END \
455 \
456 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
457 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
458 } UNSAFE_END \
459 \
460 // END DEFINE_GETSETOOP_VOLATILE.
461
462 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
463 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
464 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
465 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
466 DEFINE_GETSETOOP_VOLATILE(jint, Int);
467 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
468 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
469 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
470
471 #undef DEFINE_GETSETOOP_VOLATILE
472
473 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
474 OrderAccess::acquire();
475 } UNSAFE_END
476
477 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
478 OrderAccess::release();
479 } UNSAFE_END
480
481 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
482 OrderAccess::fence();
483 } UNSAFE_END
484
485 ////// Allocation requests
486
487 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
488 ThreadToNativeFromVM ttnfv(thread);
489 return env->AllocObject(cls);
490 } UNSAFE_END
491
492 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
493 size_t sz = (size_t)size;
494
495 sz = align_up(sz, HeapWordSize);
496 void* x = os::malloc(sz, mtOther);
497
498 return addr_to_java(x);
499 } UNSAFE_END
500
501 UNSAFE_ENTRY(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 sz = align_up(sz, HeapWordSize);
505
506 void* x = os::realloc(p, sz, mtOther);
507
508 return addr_to_java(x);
509 } UNSAFE_END
510
511 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
512 void* p = addr_from_java(addr);
513
514 os::free(p);
515 } UNSAFE_END
516
517 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
518 size_t sz = (size_t)size;
519
520 oop base = JNIHandles::resolve(obj);
521 void* p = index_oop_from_field_offset_long(base, offset);
522
523 Copy::fill_to_memory_atomic(p, sz, value);
524 } UNSAFE_END
525
526 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
527 size_t sz = (size_t)size;
528
529 oop srcp = JNIHandles::resolve(srcObj);
530 oop dstp = JNIHandles::resolve(dstObj);
531
532 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
533 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
534 {
535 GuardUnsafeAccess guard(thread);
536 if (StubRoutines::unsafe_arraycopy() != NULL) {
537 StubRoutines::UnsafeArrayCopy_stub()(src, dst, sz);
538 } else {
539 Copy::conjoint_memory_atomic(src, dst, sz);
540 }
541 }
542 } UNSAFE_END
543
544 // This function is a leaf since if the source and destination are both in native memory
545 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
546 // If either source or destination (or both) are on the heap, the function will enter VM using
547 // JVM_ENTRY_FROM_LEAF
548 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
549 size_t sz = (size_t)size;
550 size_t esz = (size_t)elemSize;
551
552 if (srcObj == NULL && dstObj == NULL) {
553 // Both src & dst are in native memory
554 address src = (address)srcOffset;
555 address dst = (address)dstOffset;
556
557 {
558 JavaThread* thread = JavaThread::thread_from_jni_environment(env);
559 GuardUnsafeAccess guard(thread);
560 Copy::conjoint_swap(src, dst, sz, esz);
561 }
562 } else {
563 // At least one of src/dst are on heap, transition to VM to access raw pointers
564
565 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
566 oop srcp = JNIHandles::resolve(srcObj);
567 oop dstp = JNIHandles::resolve(dstObj);
568
569 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
570 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
571
572 {
573 GuardUnsafeAccess guard(thread);
574 Copy::conjoint_swap(src, dst, sz, esz);
575 }
576 } JVM_END
577 }
578 } UNSAFE_END
579
580 UNSAFE_LEAF (void, Unsafe_WriteBack0(JNIEnv *env, jobject unsafe, jlong line)) {
581 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
582 #ifdef ASSERT
583 if (TraceMemoryWriteback) {
584 tty->print_cr("Unsafe: writeback 0x%p", addr_from_java(line));
585 }
586 #endif
587
588 assert(StubRoutines::data_cache_writeback() != NULL, "sanity");
589 (StubRoutines::DataCacheWriteback_stub())(addr_from_java(line));
590 } UNSAFE_END
591
592 static void doWriteBackSync0(bool is_pre)
593 {
594 assert(StubRoutines::data_cache_writeback_sync() != NULL, "sanity");
595 (StubRoutines::DataCacheWritebackSync_stub())(is_pre);
596 }
597
598 UNSAFE_LEAF (void, Unsafe_WriteBackPreSync0(JNIEnv *env, jobject unsafe)) {
599 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
600 #ifdef ASSERT
601 if (TraceMemoryWriteback) {
602 tty->print_cr("Unsafe: writeback pre-sync");
603 }
604 #endif
605
606 doWriteBackSync0(true);
607 } UNSAFE_END
608
609 UNSAFE_LEAF (void, Unsafe_WriteBackPostSync0(JNIEnv *env, jobject unsafe)) {
610 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
611 #ifdef ASSERT
612 if (TraceMemoryWriteback) {
613 tty->print_cr("Unsafe: writeback pre-sync");
614 }
615 #endif
616
617 doWriteBackSync0(false);
618 } UNSAFE_END
619
620 ////// Random queries
621
622 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
623 assert(clazz != NULL, "clazz must not be NULL");
624 assert(name != NULL, "name must not be NULL");
625
626 ResourceMark rm(THREAD);
627 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
628
629 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
630
631 jint offset = -1;
632 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
633 Symbol *name = fs.name();
634 if (name->equals(utf_name)) {
635 offset = fs.offset();
636 break;
637 }
638 }
639 if (offset < 0) {
640 THROW_0(vmSymbols::java_lang_InternalError());
641 }
642 return field_offset_from_byte_offset(offset);
643 }
644
645 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
646 assert(field != NULL, "field must not be NULL");
647
648 oop reflected = JNIHandles::resolve_non_null(field);
649 oop mirror = java_lang_reflect_Field::clazz(reflected);
650 Klass* k = java_lang_Class::as_Klass(mirror);
651 int slot = java_lang_reflect_Field::slot(reflected);
652 int modifiers = java_lang_reflect_Field::modifiers(reflected);
653
654 if (must_be_static >= 0) {
655 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
656 if (must_be_static != really_is_static) {
657 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
658 }
659 }
660
661 int offset = InstanceKlass::cast(k)->field_offset(slot);
662 return field_offset_from_byte_offset(offset);
663 }
664
665 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
666 return find_field_offset(field, 0, THREAD);
667 } UNSAFE_END
668
669 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
670 return find_field_offset(c, name, THREAD);
671 } UNSAFE_END
672
673 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
674 return find_field_offset(field, 1, THREAD);
675 } UNSAFE_END
676
677 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
678 assert(field != NULL, "field must not be NULL");
679
680 // Note: In this VM implementation, a field address is always a short
681 // offset from the base of a a klass metaobject. Thus, the full dynamic
682 // range of the return type is never used. However, some implementations
683 // might put the static field inside an array shared by many classes,
684 // or even at a fixed address, in which case the address could be quite
685 // large. In that last case, this function would return NULL, since
686 // the address would operate alone, without any base pointer.
687
688 oop reflected = JNIHandles::resolve_non_null(field);
689 oop mirror = java_lang_reflect_Field::clazz(reflected);
690 int modifiers = java_lang_reflect_Field::modifiers(reflected);
691
692 if ((modifiers & JVM_ACC_STATIC) == 0) {
693 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
694 }
695
696 return JNIHandles::make_local(env, mirror);
697 } UNSAFE_END
698
699 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
700 assert(clazz != NULL, "clazz must not be NULL");
701
702 oop mirror = JNIHandles::resolve_non_null(clazz);
703
704 Klass* klass = java_lang_Class::as_Klass(mirror);
705 if (klass != NULL && klass->should_be_initialized()) {
706 InstanceKlass* k = InstanceKlass::cast(klass);
707 k->initialize(CHECK);
708 }
709 }
710 UNSAFE_END
711
712 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
713 assert(clazz != NULL, "clazz must not be NULL");
714
715 oop mirror = JNIHandles::resolve_non_null(clazz);
716 Klass* klass = java_lang_Class::as_Klass(mirror);
717
718 if (klass != NULL && klass->should_be_initialized()) {
719 return true;
720 }
721
722 return false;
723 }
724 UNSAFE_END
725
726 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
727 assert(clazz != NULL, "clazz must not be NULL");
728
729 oop mirror = JNIHandles::resolve_non_null(clazz);
730 Klass* k = java_lang_Class::as_Klass(mirror);
731
732 if (k == NULL || !k->is_array_klass()) {
733 THROW(vmSymbols::java_lang_InvalidClassException());
734 } else if (k->is_objArray_klass()) {
735 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
736 scale = heapOopSize;
737 } else if (k->is_typeArray_klass()) {
738 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
739 base = tak->array_header_in_bytes();
740 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
741 scale = (1 << tak->log2_element_size());
742 } else if (k->is_valueArray_klass()) {
743 ValueArrayKlass* vak = ValueArrayKlass::cast(k);
744 ValueKlass* vklass = vak->element_klass();
745 base = vak->array_header_in_bytes();
746 scale = vak->element_byte_size();
747 } else {
748 ShouldNotReachHere();
749 }
750 }
751
752 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
753 int base = 0, scale = 0;
754 getBaseAndScale(base, scale, clazz, CHECK_0);
755
756 return field_offset_from_byte_offset(base);
757 } UNSAFE_END
758
759
760 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
761 int base = 0, scale = 0;
762 getBaseAndScale(base, scale, clazz, CHECK_0);
763
764 // This VM packs both fields and array elements down to the byte.
765 // But watch out: If this changes, so that array references for
766 // a given primitive type (say, T_BOOLEAN) use different memory units
767 // than fields, this method MUST return zero for such arrays.
768 // For example, the VM used to store sub-word sized fields in full
769 // words in the object layout, so that accessors like getByte(Object,int)
770 // did not really do what one might expect for arrays. Therefore,
771 // this function used to report a zero scale factor, so that the user
772 // would know not to attempt to access sub-word array elements.
773 // // Code for unpacked fields:
774 // if (scale < wordSize) return 0;
775
776 // The following allows for a pretty general fieldOffset cookie scheme,
777 // but requires it to be linear in byte offset.
778 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
779 } UNSAFE_END
780
781
782 UNSAFE_ENTRY(jlong, Unsafe_GetObjectSize0(JNIEnv* env, jobject o, jobject obj))
783 oop p = JNIHandles::resolve(obj);
784 return Universe::heap()->obj_size(p) * HeapWordSize;
785 UNSAFE_END
786
787
788 static inline void throw_new(JNIEnv *env, const char *ename) {
789 jclass cls = env->FindClass(ename);
790 if (env->ExceptionCheck()) {
791 env->ExceptionClear();
792 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
793 return;
794 }
795
796 env->ThrowNew(cls, NULL);
797 }
798
799 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
800 // Code lifted from JDK 1.3 ClassLoader.c
801
802 jbyte *body;
803 char *utfName = NULL;
804 jclass result = 0;
805 char buf[128];
806
807 assert(data != NULL, "Class bytes must not be NULL");
808 assert(length >= 0, "length must not be negative: %d", length);
809
810 if (UsePerfData) {
811 ClassLoader::unsafe_defineClassCallCounter()->inc();
812 }
813
814 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
815 if (body == NULL) {
816 throw_new(env, "java/lang/OutOfMemoryError");
817 return 0;
818 }
819
820 env->GetByteArrayRegion(data, offset, length, body);
821 if (env->ExceptionOccurred()) {
822 goto free_body;
823 }
824
825 if (name != NULL) {
826 uint len = env->GetStringUTFLength(name);
827 int unicode_len = env->GetStringLength(name);
828
829 if (len >= sizeof(buf)) {
830 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
831 if (utfName == NULL) {
832 throw_new(env, "java/lang/OutOfMemoryError");
833 goto free_body;
834 }
835 } else {
836 utfName = buf;
837 }
838
839 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
840
841 for (uint i = 0; i < len; i++) {
842 if (utfName[i] == '.') utfName[i] = '/';
843 }
844 }
845
846 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
847
848 if (utfName && utfName != buf) {
849 FREE_C_HEAP_ARRAY(char, utfName);
850 }
851
852 free_body:
853 FREE_C_HEAP_ARRAY(jbyte, body);
854 return result;
855 }
856
857
858 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
859 ThreadToNativeFromVM ttnfv(thread);
860
861 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
862 } UNSAFE_END
863
864
865 // define a class but do not make it known to the class loader or system dictionary
866 // - host_class: supplies context for linkage, access control, protection domain, and class loader
867 // if host_class is itself anonymous then it is replaced with its host class.
868 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
869 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
870
871 // When you load an anonymous class U, it works as if you changed its name just before loading,
872 // to a name that you will never use again. Since the name is lost, no other class can directly
873 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
874 // through java.lang.Class methods like Class.newInstance.
875
876 // The package of an anonymous class must either match its host's class's package or be in the
877 // unnamed package. If it is in the unnamed package then it will be put in its host class's
878 // package.
879 //
880
881 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
882 // An anonymous class also has special privileges to access any member of its host class.
883 // This is the main reason why this loading operation is unsafe. The purpose of this is to
884 // allow language implementations to simulate "open classes"; a host class in effect gets
885 // new code when an anonymous class is loaded alongside it. A less convenient but more
886 // standard way to do this is with reflection, which can also be set to ignore access
887 // restrictions.
888
889 // Access into an anonymous class is possible only through reflection. Therefore, there
890 // are no special access rules for calling into an anonymous class. The relaxed access
891 // rule for the host class is applied in the opposite direction: A host class reflectively
892 // access one of its anonymous classes.
893
894 // If you load the same bytecodes twice, you get two different classes. You can reload
895 // the same bytecodes with or without varying CP patches.
896
897 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
898 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
899 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
900
901 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
902 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
903 // It is not possible for a named class, or an older anonymous class, to refer by
904 // name (via its CP) to a newer anonymous class.
905
906 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
907 // or type descriptors used in the loaded anonymous class.
908
909 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
910 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
911 // be changed to println(greeting), where greeting is an arbitrary object created before
912 // the anonymous class is loaded. This is useful in dynamic languages, in which
913 // various kinds of metaobjects must be introduced as constants into bytecode.
914 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
915 // not just a literal string. For such ldc instructions, the verifier uses the
916 // type Object instead of String, if the loaded constant is not in fact a String.
917
918 static InstanceKlass*
919 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
920 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
921 u1** temp_alloc,
922 TRAPS) {
923 assert(host_class != NULL, "host_class must not be NULL");
924 assert(data != NULL, "data must not be NULL");
925
926 if (UsePerfData) {
927 ClassLoader::unsafe_defineClassCallCounter()->inc();
928 }
929
930 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
931 assert(length >= 0, "class_bytes_length must not be negative: %d", length);
932
933 int class_bytes_length = (int) length;
934
935 u1* class_bytes = NEW_C_HEAP_ARRAY(u1, length, mtInternal);
936 if (class_bytes == NULL) {
937 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
938 }
939
940 // caller responsible to free it:
941 *temp_alloc = class_bytes;
942
943 ArrayAccess<>::arraycopy_to_native(arrayOop(JNIHandles::resolve_non_null(data)), typeArrayOopDesc::element_offset<jbyte>(0),
944 reinterpret_cast<jbyte*>(class_bytes), length);
945
946 objArrayHandle cp_patches_h;
947 if (cp_patches_jh != NULL) {
948 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
949 assert(p->is_objArray(), "cp_patches must be an object[]");
950 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
951 }
952
953 const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
954
955 // Make sure it's the real host class, not another anonymous class.
956 while (host_klass != NULL && host_klass->is_instance_klass() &&
957 InstanceKlass::cast(host_klass)->is_unsafe_anonymous()) {
958 host_klass = InstanceKlass::cast(host_klass)->unsafe_anonymous_host();
959 }
960
961 // Primitive types have NULL Klass* fields in their java.lang.Class instances.
962 if (host_klass == NULL) {
963 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
964 }
965
966 assert(host_klass->is_instance_klass(), "Host class must be an instance class");
967
968 const char* host_source = host_klass->external_name();
969 Handle host_loader(THREAD, host_klass->class_loader());
970 Handle host_domain(THREAD, host_klass->protection_domain());
971
972 GrowableArray<Handle>* cp_patches = NULL;
973
974 if (cp_patches_h.not_null()) {
975 int alen = cp_patches_h->length();
976
977 for (int i = alen-1; i >= 0; i--) {
978 oop p = cp_patches_h->obj_at(i);
979 if (p != NULL) {
980 Handle patch(THREAD, p);
981
982 if (cp_patches == NULL) {
983 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
984 }
985
986 cp_patches->at_put(i, patch);
987 }
988 }
989 }
990
991 ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
992
993 Symbol* no_class_name = NULL;
994 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
995 host_loader,
996 host_domain,
997 &st,
998 InstanceKlass::cast(host_klass),
999 cp_patches,
1000 CHECK_NULL);
1001 if (anonk == NULL) {
1002 return NULL;
1003 }
1004
1005 return InstanceKlass::cast(anonk);
1006 }
1007
1008 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
1009 ResourceMark rm(THREAD);
1010
1011 jobject res_jh = NULL;
1012 u1* temp_alloc = NULL;
1013
1014 InstanceKlass* anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
1015 if (anon_klass != NULL) {
1016 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
1017 }
1018
1019 // try/finally clause:
1020 FREE_C_HEAP_ARRAY(u1, temp_alloc);
1021
1022 // The anonymous class loader data has been artificially been kept alive to
1023 // this point. The mirror and any instances of this class have to keep
1024 // it alive afterwards.
1025 if (anon_klass != NULL) {
1026 anon_klass->class_loader_data()->dec_keep_alive();
1027 }
1028
1029 // let caller initialize it as needed...
1030
1031 return (jclass) res_jh;
1032 } UNSAFE_END
1033
1034
1035
1036 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
1037 ThreadToNativeFromVM ttnfv(thread);
1038 env->Throw(thr);
1039 } UNSAFE_END
1040
1041 // JSR166 ------------------------------------------------------------------
1042
1043 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1044 oop x = JNIHandles::resolve(x_h);
1045 oop e = JNIHandles::resolve(e_h);
1046 oop p = JNIHandles::resolve(obj);
1047 assert_field_offset_sane(p, offset);
1048 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1049 return JNIHandles::make_local(env, res);
1050 } UNSAFE_END
1051
1052 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1053 oop p = JNIHandles::resolve(obj);
1054 if (p == NULL) {
1055 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1056 return RawAccess<>::atomic_cmpxchg(x, addr, e);
1057 } else {
1058 assert_field_offset_sane(p, offset);
1059 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1060 }
1061 } UNSAFE_END
1062
1063 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1064 oop p = JNIHandles::resolve(obj);
1065 if (p == NULL) {
1066 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1067 return RawAccess<>::atomic_cmpxchg(x, addr, e);
1068 } else {
1069 assert_field_offset_sane(p, offset);
1070 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1071 }
1072 } UNSAFE_END
1073
1074 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1075 oop x = JNIHandles::resolve(x_h);
1076 oop e = JNIHandles::resolve(e_h);
1077 oop p = JNIHandles::resolve(obj);
1078 assert_field_offset_sane(p, offset);
1079 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
1080 return ret == e;
1081 } UNSAFE_END
1082
1083 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1084 oop p = JNIHandles::resolve(obj);
1085 if (p == NULL) {
1086 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1087 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
1088 } else {
1089 assert_field_offset_sane(p, offset);
1090 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
1091 }
1092 } UNSAFE_END
1093
1094 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1095 oop p = JNIHandles::resolve(obj);
1096 if (p == NULL) {
1097 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1098 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
1099 } else {
1100 assert_field_offset_sane(p, offset);
1101 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
1102 }
1103 } UNSAFE_END
1104
1105 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) {
1106 assert(event != NULL, "invariant");
1107 assert(event->should_commit(), "invariant");
1108 event->set_parkedClass((obj != NULL) ? obj->klass() : NULL);
1109 event->set_timeout(timeout_nanos);
1110 event->set_until(until_epoch_millis);
1111 event->set_address((obj != NULL) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1112 event->commit();
1113 }
1114
1115 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1116 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1117 EventThreadPark event;
1118
1119 JavaThreadParkedState jtps(thread, time != 0);
1120 thread->parker()->park(isAbsolute != 0, time);
1121 if (event.should_commit()) {
1122 const oop obj = thread->current_park_blocker();
1123 if (time == 0) {
1124 post_thread_park_event(&event, obj, min_jlong, min_jlong);
1125 } else {
1126 if (isAbsolute != 0) {
1127 post_thread_park_event(&event, obj, min_jlong, time);
1128 } else {
1129 post_thread_park_event(&event, obj, time, min_jlong);
1130 }
1131 }
1132 }
1133 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1134 } UNSAFE_END
1135
1136 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1137 Parker* p = NULL;
1138
1139 if (jthread != NULL) {
1140 ThreadsListHandle tlh;
1141 JavaThread* thr = NULL;
1142 oop java_thread = NULL;
1143 (void) tlh.cv_internal_thread_to_JavaThread(jthread, &thr, &java_thread);
1144 if (java_thread != NULL) {
1145 // This is a valid oop.
1146 if (thr != NULL) {
1147 // The JavaThread is alive.
1148 p = thr->parker();
1149 }
1150 }
1151 } // ThreadsListHandle is destroyed here.
1152
1153 // 'p' points to type-stable-memory if non-NULL. If the target
1154 // thread terminates before we get here the new user of this
1155 // Parker will get a 'spurious' unpark - which is perfectly valid.
1156 if (p != NULL) {
1157 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1158 p->unpark();
1159 }
1160 } UNSAFE_END
1161
1162 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1163 const int max_nelem = 3;
1164 double la[max_nelem];
1165 jint ret;
1166
1167 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1168 assert(a->is_typeArray(), "must be type array");
1169
1170 ret = os::loadavg(la, nelem);
1171 if (ret == -1) {
1172 return -1;
1173 }
1174
1175 // if successful, ret is the number of samples actually retrieved.
1176 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1177 switch(ret) {
1178 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1179 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1180 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1181 }
1182
1183 return ret;
1184 } UNSAFE_END
1185
1186
1187 /// JVM_RegisterUnsafeMethods
1188
1189 #define ADR "J"
1190
1191 #define LANG "Ljava/lang/"
1192
1193 #define OBJ LANG "Object;"
1194 #define CLS LANG "Class;"
1195 #define FLD LANG "reflect/Field;"
1196 #define THR LANG "Throwable;"
1197
1198 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1199 #define DAC_Args CLS "[B[" OBJ
1200
1201 #define CC (char*) /*cast a literal from (const char*)*/
1202 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1203
1204 #define DECLARE_GETPUTOOP(Type, Desc) \
1205 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1206 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1207 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1208 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1209
1210
1211 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1212 {CC "getReference", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetReference)},
1213 {CC "putReference", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReference)},
1214 {CC "getReferenceVolatile", CC "(" OBJ "J)" OBJ, FN_PTR(Unsafe_GetReferenceVolatile)},
1215 {CC "putReferenceVolatile", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReferenceVolatile)},
1216
1217 {CC "isFlattenedArray", CC "(" CLS ")Z", FN_PTR(Unsafe_IsFlattenedArray)},
1218 {CC "getValue", CC "(" OBJ "J" CLS ")" OBJ, FN_PTR(Unsafe_GetValue)},
1219 {CC "putValue", CC "(" OBJ "J" CLS OBJ ")V", FN_PTR(Unsafe_PutValue)},
1220 {CC "uninitializedDefaultValue", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_UninitializedDefaultValue)},
1221 {CC "makePrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_MakePrivateBuffer)},
1222 {CC "finishPrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_FinishPrivateBuffer)},
1223 {CC "valueHeaderSize", CC "(" CLS ")J", FN_PTR(Unsafe_ValueHeaderSize)},
1224
1225 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1226
1227 DECLARE_GETPUTOOP(Boolean, Z),
1228 DECLARE_GETPUTOOP(Byte, B),
1229 DECLARE_GETPUTOOP(Short, S),
1230 DECLARE_GETPUTOOP(Char, C),
1231 DECLARE_GETPUTOOP(Int, I),
1232 DECLARE_GETPUTOOP(Long, J),
1233 DECLARE_GETPUTOOP(Float, F),
1234 DECLARE_GETPUTOOP(Double, D),
1235
1236 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1237 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1238 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1239
1240 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1241 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1242 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1243 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1244 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1245 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1246 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1247 {CC "getObjectSize0", CC "(Ljava/lang/Object;)J", FN_PTR(Unsafe_GetObjectSize0)},
1248
1249 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1250 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1251 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1252 {CC "compareAndSetReference",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetReference)},
1253 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1254 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1255 {CC "compareAndExchangeReference", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeReference)},
1256 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1257 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1258
1259 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1260 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1261
1262 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1263
1264 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1265 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1266 {CC "writeback0", CC "(" "J" ")V", FN_PTR(Unsafe_WriteBack0)},
1267 {CC "writebackPreSync0", CC "()V", FN_PTR(Unsafe_WriteBackPreSync0)},
1268 {CC "writebackPostSync0", CC "()V", FN_PTR(Unsafe_WriteBackPostSync0)},
1269 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1270
1271 {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1272
1273 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1274
1275 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1276 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1277 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1278 };
1279
1280 #undef CC
1281 #undef FN_PTR
1282
1283 #undef ADR
1284 #undef LANG
1285 #undef OBJ
1286 #undef CLS
1287 #undef FLD
1288 #undef THR
1289 #undef DC_Args
1290 #undef DAC_Args
1291
1292 #undef DECLARE_GETPUTOOP
1293
1294
1295 // This function is exported, used by NativeLookup.
1296 // The Unsafe_xxx functions above are called only from the interpreter.
1297 // The optimizer looks at names and signatures to recognize
1298 // individual functions.
1299
1300 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1301 ThreadToNativeFromVM ttnfv(thread);
1302
1303 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1304 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1305 } JVM_END