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/vmSymbols.hpp"
30 #include "jfr/jfrEvents.hpp"
31 #include "memory/allocation.inline.hpp"
32 #include "memory/resourceArea.hpp"
33 #include "oops/access.inline.hpp"
34 #include "oops/fieldStreams.hpp"
35 #include "oops/objArrayOop.inline.hpp"
36 #include "oops/oop.inline.hpp"
37 #include "oops/typeArrayOop.inline.hpp"
38 #include "prims/unsafe.hpp"
39 #include "runtime/atomic.hpp"
40 #include "runtime/globals.hpp"
41 #include "runtime/interfaceSupport.inline.hpp"
42 #include "runtime/jniHandles.inline.hpp"
43 #include "runtime/orderAccess.hpp"
44 #include "runtime/reflection.hpp"
45 #include "runtime/thread.hpp"
46 #include "runtime/threadSMR.hpp"
47 #include "runtime/vm_version.hpp"
48 #include "services/threadService.hpp"
49 #include "utilities/align.hpp"
50 #include "utilities/copy.hpp"
51 #include "utilities/dtrace.hpp"
52 #include "utilities/macros.hpp"
53
54 /**
55 * Implementation of the jdk.internal.misc.Unsafe class
56 */
57
58
59 #define MAX_OBJECT_SIZE \
60 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
61 + ((julong)max_jint * sizeof(double)) )
62
63
64 #define UNSAFE_ENTRY(result_type, header) \
65 JVM_ENTRY(static result_type, header)
66
67 #define UNSAFE_LEAF(result_type, header) \
68 JVM_LEAF(static result_type, header)
69
70 #define UNSAFE_END JVM_END
71
72
addr_from_java(jlong addr)73 static inline void* addr_from_java(jlong addr) {
74 // This assert fails in a variety of ways on 32-bit systems.
75 // It is impossible to predict whether native code that converts
76 // pointers to longs will sign-extend or zero-extend the addresses.
77 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
78 return (void*)(uintptr_t)addr;
79 }
80
addr_to_java(void * p)81 static inline jlong addr_to_java(void* p) {
82 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
83 return (uintptr_t)p;
84 }
85
86
87 // Note: The VM's obj_field and related accessors use byte-scaled
88 // ("unscaled") offsets, just as the unsafe methods do.
89
90 // However, the method Unsafe.fieldOffset explicitly declines to
91 // guarantee this. The field offset values manipulated by the Java user
92 // through the Unsafe API are opaque cookies that just happen to be byte
93 // offsets. We represent this state of affairs by passing the cookies
94 // through conversion functions when going between the VM and the Unsafe API.
95 // The conversion functions just happen to be no-ops at present.
96
field_offset_to_byte_offset(jlong field_offset)97 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
98 return field_offset;
99 }
100
field_offset_from_byte_offset(jlong byte_offset)101 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
102 return byte_offset;
103 }
104
assert_field_offset_sane(oop p,jlong field_offset)105 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
106 #ifdef ASSERT
107 jlong byte_offset = field_offset_to_byte_offset(field_offset);
108
109 if (p != NULL) {
110 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
111 if (byte_offset == (jint)byte_offset) {
112 void* ptr_plus_disp = (address)p + byte_offset;
113 assert(p->field_addr_raw((jint)byte_offset) == ptr_plus_disp,
114 "raw [ptr+disp] must be consistent with oop::field_addr_raw");
115 }
116 jlong p_size = HeapWordSize * (jlong)(p->size());
117 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
118 }
119 #endif
120 }
121
index_oop_from_field_offset_long(oop p,jlong field_offset)122 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
123 assert_field_offset_sane(p, field_offset);
124 jlong byte_offset = field_offset_to_byte_offset(field_offset);
125
126 if (p != NULL) {
127 p = Access<>::resolve(p);
128 }
129
130 if (sizeof(char*) == sizeof(jint)) { // (this constant folds!)
131 return (address)p + (jint) byte_offset;
132 } else {
133 return (address)p + byte_offset;
134 }
135 }
136
137 // Externally callable versions:
138 // (Use these in compiler intrinsics which emulate unsafe primitives.)
Unsafe_field_offset_to_byte_offset(jlong field_offset)139 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
140 return field_offset;
141 }
Unsafe_field_offset_from_byte_offset(jlong byte_offset)142 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
143 return byte_offset;
144 }
145
146
147 ///// Data read/writes on the Java heap and in native (off-heap) memory
148
149 /**
150 * Helper class for accessing memory.
151 *
152 * Normalizes values and wraps accesses in
153 * JavaThread::doing_unsafe_access() if needed.
154 */
155 template <typename T>
156 class MemoryAccess : StackObj {
157 JavaThread* _thread;
158 oop _obj;
159 ptrdiff_t _offset;
160
161 // Resolves and returns the address of the memory access.
162 // This raw memory access may fault, so we make sure it happens within the
163 // guarded scope by making the access volatile at least. Since the store
164 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
165 // can not be reordered by the compiler. Therefore, if the access triggers
166 // a fault, we will know that Thread::doing_unsafe_access() returns true.
addr()167 volatile T* addr() {
168 void* addr = index_oop_from_field_offset_long(_obj, _offset);
169 return static_cast<volatile T*>(addr);
170 }
171
172 template <typename U>
normalize_for_write(U x)173 U normalize_for_write(U x) {
174 return x;
175 }
176
normalize_for_write(jboolean x)177 jboolean normalize_for_write(jboolean x) {
178 return x & 1;
179 }
180
181 template <typename U>
normalize_for_read(U x)182 U normalize_for_read(U x) {
183 return x;
184 }
185
normalize_for_read(jboolean x)186 jboolean normalize_for_read(jboolean x) {
187 return x != 0;
188 }
189
190 /**
191 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
192 */
193 class GuardUnsafeAccess {
194 JavaThread* _thread;
195
196 public:
GuardUnsafeAccess(JavaThread * thread)197 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
198 // native/off-heap access which may raise SIGBUS if accessing
199 // memory mapped file data in a region of the file which has
200 // been truncated and is now invalid
201 _thread->set_doing_unsafe_access(true);
202 }
203
~GuardUnsafeAccess()204 ~GuardUnsafeAccess() {
205 _thread->set_doing_unsafe_access(false);
206 }
207 };
208
209 public:
MemoryAccess(JavaThread * thread,jobject obj,jlong offset)210 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
211 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
212 assert_field_offset_sane(_obj, offset);
213 }
214
get()215 T get() {
216 if (_obj == NULL) {
217 GuardUnsafeAccess guard(_thread);
218 T ret = RawAccess<>::load(addr());
219 return normalize_for_read(ret);
220 } else {
221 T ret = HeapAccess<>::load_at(_obj, _offset);
222 return normalize_for_read(ret);
223 }
224 }
225
put(T x)226 void put(T x) {
227 if (_obj == NULL) {
228 GuardUnsafeAccess guard(_thread);
229 RawAccess<>::store(addr(), normalize_for_write(x));
230 } else {
231 HeapAccess<>::store_at(_obj, _offset, normalize_for_write(x));
232 }
233 }
234
235
get_volatile()236 T get_volatile() {
237 if (_obj == NULL) {
238 GuardUnsafeAccess guard(_thread);
239 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
240 return normalize_for_read(ret);
241 } else {
242 T ret = HeapAccess<MO_SEQ_CST>::load_at(_obj, _offset);
243 return normalize_for_read(ret);
244 }
245 }
246
put_volatile(T x)247 void put_volatile(T x) {
248 if (_obj == NULL) {
249 GuardUnsafeAccess guard(_thread);
250 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
251 } else {
252 HeapAccess<MO_SEQ_CST>::store_at(_obj, _offset, normalize_for_write(x));
253 }
254 }
255 };
256
257 // These functions allow a null base pointer with an arbitrary address.
258 // But if the base pointer is non-null, the offset should make some sense.
259 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
UNSAFE_ENTRY(jobject,Unsafe_GetObject (JNIEnv * env,jobject unsafe,jobject obj,jlong offset))260 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
261 oop p = JNIHandles::resolve(obj);
262 assert_field_offset_sane(p, offset);
263 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
264 return JNIHandles::make_local(env, v);
265 } UNSAFE_END
266
UNSAFE_ENTRY(void,Unsafe_PutObject (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jobject x_h))267 UNSAFE_ENTRY(void, Unsafe_PutObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
268 oop x = JNIHandles::resolve(x_h);
269 oop p = JNIHandles::resolve(obj);
270 assert_field_offset_sane(p, offset);
271 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
272 } UNSAFE_END
273
UNSAFE_ENTRY(jobject,Unsafe_GetObjectVolatile (JNIEnv * env,jobject unsafe,jobject obj,jlong offset))274 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
275 oop p = JNIHandles::resolve(obj);
276 assert_field_offset_sane(p, offset);
277 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
278 return JNIHandles::make_local(env, v);
279 } UNSAFE_END
280
UNSAFE_ENTRY(void,Unsafe_PutObjectVolatile (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jobject x_h))281 UNSAFE_ENTRY(void, Unsafe_PutObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
282 oop x = JNIHandles::resolve(x_h);
283 oop p = JNIHandles::resolve(obj);
284 assert_field_offset_sane(p, offset);
285 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
286 } UNSAFE_END
287
UNSAFE_ENTRY(jobject,Unsafe_GetUncompressedObject (JNIEnv * env,jobject unsafe,jlong addr))288 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
289 oop v = *(oop*) (address) addr;
290 return JNIHandles::make_local(env, v);
291 } UNSAFE_END
292
UNSAFE_LEAF(jboolean,Unsafe_isBigEndian0 (JNIEnv * env,jobject unsafe))293 UNSAFE_LEAF(jboolean, Unsafe_isBigEndian0(JNIEnv *env, jobject unsafe)) {
294 #ifdef VM_LITTLE_ENDIAN
295 return false;
296 #else
297 return true;
298 #endif
299 } UNSAFE_END
300
UNSAFE_LEAF(jint,Unsafe_unalignedAccess0 (JNIEnv * env,jobject unsafe))301 UNSAFE_LEAF(jint, Unsafe_unalignedAccess0(JNIEnv *env, jobject unsafe)) {
302 return UseUnalignedAccesses;
303 } UNSAFE_END
304
305 #define DEFINE_GETSETOOP(java_type, Type) \
306 \
307 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
308 return MemoryAccess<java_type>(thread, obj, offset).get(); \
309 } UNSAFE_END \
310 \
311 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
312 MemoryAccess<java_type>(thread, obj, offset).put(x); \
313 } UNSAFE_END \
314 \
315 // END DEFINE_GETSETOOP.
316
317 DEFINE_GETSETOOP(jboolean, Boolean)
318 DEFINE_GETSETOOP(jbyte, Byte)
319 DEFINE_GETSETOOP(jshort, Short);
320 DEFINE_GETSETOOP(jchar, Char);
321 DEFINE_GETSETOOP(jint, Int);
322 DEFINE_GETSETOOP(jlong, Long);
323 DEFINE_GETSETOOP(jfloat, Float);
324 DEFINE_GETSETOOP(jdouble, Double);
325
326 #undef DEFINE_GETSETOOP
327
328 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
329 \
330 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
331 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
332 } UNSAFE_END \
333 \
334 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
335 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
336 } UNSAFE_END \
337 \
338 // END DEFINE_GETSETOOP_VOLATILE.
339
340 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
341 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
342 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
343 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
344 DEFINE_GETSETOOP_VOLATILE(jint, Int);
345 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
346 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
347 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
348
349 #undef DEFINE_GETSETOOP_VOLATILE
350
UNSAFE_LEAF(void,Unsafe_LoadFence (JNIEnv * env,jobject unsafe))351 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
352 OrderAccess::acquire();
353 } UNSAFE_END
354
UNSAFE_LEAF(void,Unsafe_StoreFence (JNIEnv * env,jobject unsafe))355 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
356 OrderAccess::release();
357 } UNSAFE_END
358
UNSAFE_LEAF(void,Unsafe_FullFence (JNIEnv * env,jobject unsafe))359 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
360 OrderAccess::fence();
361 } UNSAFE_END
362
363 ////// Allocation requests
364
UNSAFE_ENTRY(jobject,Unsafe_AllocateInstance (JNIEnv * env,jobject unsafe,jclass cls))365 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
366 ThreadToNativeFromVM ttnfv(thread);
367 return env->AllocObject(cls);
368 } UNSAFE_END
369
UNSAFE_ENTRY(jlong,Unsafe_AllocateMemory0 (JNIEnv * env,jobject unsafe,jlong size))370 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
371 size_t sz = (size_t)size;
372
373 sz = align_up(sz, HeapWordSize);
374 void* x = os::malloc(sz, mtOther);
375
376 return addr_to_java(x);
377 } UNSAFE_END
378
UNSAFE_ENTRY(jlong,Unsafe_ReallocateMemory0 (JNIEnv * env,jobject unsafe,jlong addr,jlong size))379 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
380 void* p = addr_from_java(addr);
381 size_t sz = (size_t)size;
382 sz = align_up(sz, HeapWordSize);
383
384 void* x = os::realloc(p, sz, mtOther);
385
386 return addr_to_java(x);
387 } UNSAFE_END
388
UNSAFE_ENTRY(void,Unsafe_FreeMemory0 (JNIEnv * env,jobject unsafe,jlong addr))389 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
390 void* p = addr_from_java(addr);
391
392 os::free(p);
393 } UNSAFE_END
394
UNSAFE_ENTRY(void,Unsafe_SetMemory0 (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jlong size,jbyte value))395 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
396 size_t sz = (size_t)size;
397
398 oop base = JNIHandles::resolve(obj);
399 void* p = index_oop_from_field_offset_long(base, offset);
400
401 Copy::fill_to_memory_atomic(p, sz, value);
402 } UNSAFE_END
403
UNSAFE_ENTRY(void,Unsafe_CopyMemory0 (JNIEnv * env,jobject unsafe,jobject srcObj,jlong srcOffset,jobject dstObj,jlong dstOffset,jlong size))404 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
405 size_t sz = (size_t)size;
406
407 oop srcp = JNIHandles::resolve(srcObj);
408 oop dstp = JNIHandles::resolve(dstObj);
409
410 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
411 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
412
413 Copy::conjoint_memory_atomic(src, dst, sz);
414 } UNSAFE_END
415
416 // This function is a leaf since if the source and destination are both in native memory
417 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
418 // If either source or destination (or both) are on the heap, the function will enter VM using
419 // JVM_ENTRY_FROM_LEAF
UNSAFE_LEAF(void,Unsafe_CopySwapMemory0 (JNIEnv * env,jobject unsafe,jobject srcObj,jlong srcOffset,jobject dstObj,jlong dstOffset,jlong size,jlong elemSize))420 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
421 size_t sz = (size_t)size;
422 size_t esz = (size_t)elemSize;
423
424 if (srcObj == NULL && dstObj == NULL) {
425 // Both src & dst are in native memory
426 address src = (address)srcOffset;
427 address dst = (address)dstOffset;
428
429 Copy::conjoint_swap(src, dst, sz, esz);
430 } else {
431 // At least one of src/dst are on heap, transition to VM to access raw pointers
432
433 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
434 oop srcp = JNIHandles::resolve(srcObj);
435 oop dstp = JNIHandles::resolve(dstObj);
436
437 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
438 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
439
440 Copy::conjoint_swap(src, dst, sz, esz);
441 } JVM_END
442 }
443 } UNSAFE_END
444
445 ////// Random queries
446
UNSAFE_LEAF(jint,Unsafe_AddressSize0 (JNIEnv * env,jobject unsafe))447 UNSAFE_LEAF(jint, Unsafe_AddressSize0(JNIEnv *env, jobject unsafe)) {
448 return sizeof(void*);
449 } UNSAFE_END
450
UNSAFE_LEAF(jint,Unsafe_PageSize ())451 UNSAFE_LEAF(jint, Unsafe_PageSize()) {
452 return os::vm_page_size();
453 } UNSAFE_END
454
find_field_offset(jclass clazz,jstring name,TRAPS)455 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
456 assert(clazz != NULL, "clazz must not be NULL");
457 assert(name != NULL, "name must not be NULL");
458
459 ResourceMark rm(THREAD);
460 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
461
462 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
463
464 jint offset = -1;
465 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
466 Symbol *name = fs.name();
467 if (name->equals(utf_name)) {
468 offset = fs.offset();
469 break;
470 }
471 }
472 if (offset < 0) {
473 THROW_0(vmSymbols::java_lang_InternalError());
474 }
475 return field_offset_from_byte_offset(offset);
476 }
477
find_field_offset(jobject field,int must_be_static,TRAPS)478 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
479 assert(field != NULL, "field must not be NULL");
480
481 oop reflected = JNIHandles::resolve_non_null(field);
482 oop mirror = java_lang_reflect_Field::clazz(reflected);
483 Klass* k = java_lang_Class::as_Klass(mirror);
484 int slot = java_lang_reflect_Field::slot(reflected);
485 int modifiers = java_lang_reflect_Field::modifiers(reflected);
486
487 if (must_be_static >= 0) {
488 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
489 if (must_be_static != really_is_static) {
490 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
491 }
492 }
493
494 int offset = InstanceKlass::cast(k)->field_offset(slot);
495 return field_offset_from_byte_offset(offset);
496 }
497
UNSAFE_ENTRY(jlong,Unsafe_ObjectFieldOffset0 (JNIEnv * env,jobject unsafe,jobject field))498 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
499 return find_field_offset(field, 0, THREAD);
500 } UNSAFE_END
501
UNSAFE_ENTRY(jlong,Unsafe_ObjectFieldOffset1 (JNIEnv * env,jobject unsafe,jclass c,jstring name))502 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
503 return find_field_offset(c, name, THREAD);
504 } UNSAFE_END
505
UNSAFE_ENTRY(jlong,Unsafe_StaticFieldOffset0 (JNIEnv * env,jobject unsafe,jobject field))506 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
507 return find_field_offset(field, 1, THREAD);
508 } UNSAFE_END
509
UNSAFE_ENTRY(jobject,Unsafe_StaticFieldBase0 (JNIEnv * env,jobject unsafe,jobject field))510 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
511 assert(field != NULL, "field must not be NULL");
512
513 // Note: In this VM implementation, a field address is always a short
514 // offset from the base of a a klass metaobject. Thus, the full dynamic
515 // range of the return type is never used. However, some implementations
516 // might put the static field inside an array shared by many classes,
517 // or even at a fixed address, in which case the address could be quite
518 // large. In that last case, this function would return NULL, since
519 // the address would operate alone, without any base pointer.
520
521 oop reflected = JNIHandles::resolve_non_null(field);
522 oop mirror = java_lang_reflect_Field::clazz(reflected);
523 int modifiers = java_lang_reflect_Field::modifiers(reflected);
524
525 if ((modifiers & JVM_ACC_STATIC) == 0) {
526 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
527 }
528
529 return JNIHandles::make_local(env, mirror);
530 } UNSAFE_END
531
UNSAFE_ENTRY(void,Unsafe_EnsureClassInitialized0 (JNIEnv * env,jobject unsafe,jobject clazz))532 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
533 assert(clazz != NULL, "clazz must not be NULL");
534
535 oop mirror = JNIHandles::resolve_non_null(clazz);
536
537 Klass* klass = java_lang_Class::as_Klass(mirror);
538 if (klass != NULL && klass->should_be_initialized()) {
539 InstanceKlass* k = InstanceKlass::cast(klass);
540 k->initialize(CHECK);
541 }
542 }
543 UNSAFE_END
544
UNSAFE_ENTRY(jboolean,Unsafe_ShouldBeInitialized0 (JNIEnv * env,jobject unsafe,jobject clazz))545 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
546 assert(clazz != NULL, "clazz must not be NULL");
547
548 oop mirror = JNIHandles::resolve_non_null(clazz);
549 Klass* klass = java_lang_Class::as_Klass(mirror);
550
551 if (klass != NULL && klass->should_be_initialized()) {
552 return true;
553 }
554
555 return false;
556 }
557 UNSAFE_END
558
getBaseAndScale(int & base,int & scale,jclass clazz,TRAPS)559 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
560 assert(clazz != NULL, "clazz must not be NULL");
561
562 oop mirror = JNIHandles::resolve_non_null(clazz);
563 Klass* k = java_lang_Class::as_Klass(mirror);
564
565 if (k == NULL || !k->is_array_klass()) {
566 THROW(vmSymbols::java_lang_InvalidClassException());
567 } else if (k->is_objArray_klass()) {
568 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
569 scale = heapOopSize;
570 } else if (k->is_typeArray_klass()) {
571 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
572 base = tak->array_header_in_bytes();
573 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
574 scale = (1 << tak->log2_element_size());
575 } else {
576 ShouldNotReachHere();
577 }
578 }
579
UNSAFE_ENTRY(jint,Unsafe_ArrayBaseOffset0 (JNIEnv * env,jobject unsafe,jclass clazz))580 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
581 int base = 0, scale = 0;
582 getBaseAndScale(base, scale, clazz, CHECK_0);
583
584 return field_offset_from_byte_offset(base);
585 } UNSAFE_END
586
587
UNSAFE_ENTRY(jint,Unsafe_ArrayIndexScale0 (JNIEnv * env,jobject unsafe,jclass clazz))588 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
589 int base = 0, scale = 0;
590 getBaseAndScale(base, scale, clazz, CHECK_0);
591
592 // This VM packs both fields and array elements down to the byte.
593 // But watch out: If this changes, so that array references for
594 // a given primitive type (say, T_BOOLEAN) use different memory units
595 // than fields, this method MUST return zero for such arrays.
596 // For example, the VM used to store sub-word sized fields in full
597 // words in the object layout, so that accessors like getByte(Object,int)
598 // did not really do what one might expect for arrays. Therefore,
599 // this function used to report a zero scale factor, so that the user
600 // would know not to attempt to access sub-word array elements.
601 // // Code for unpacked fields:
602 // if (scale < wordSize) return 0;
603
604 // The following allows for a pretty general fieldOffset cookie scheme,
605 // but requires it to be linear in byte offset.
606 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
607 } UNSAFE_END
608
609
throw_new(JNIEnv * env,const char * ename)610 static inline void throw_new(JNIEnv *env, const char *ename) {
611 jclass cls = env->FindClass(ename);
612 if (env->ExceptionCheck()) {
613 env->ExceptionClear();
614 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
615 return;
616 }
617
618 env->ThrowNew(cls, NULL);
619 }
620
Unsafe_DefineClass_impl(JNIEnv * env,jstring name,jbyteArray data,int offset,int length,jobject loader,jobject pd)621 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
622 // Code lifted from JDK 1.3 ClassLoader.c
623
624 jbyte *body;
625 char *utfName = NULL;
626 jclass result = 0;
627 char buf[128];
628
629 assert(data != NULL, "Class bytes must not be NULL");
630 assert(length >= 0, "length must not be negative: %d", length);
631
632 if (UsePerfData) {
633 ClassLoader::unsafe_defineClassCallCounter()->inc();
634 }
635
636 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
637 if (body == NULL) {
638 throw_new(env, "java/lang/OutOfMemoryError");
639 return 0;
640 }
641
642 env->GetByteArrayRegion(data, offset, length, body);
643 if (env->ExceptionOccurred()) {
644 goto free_body;
645 }
646
647 if (name != NULL) {
648 uint len = env->GetStringUTFLength(name);
649 int unicode_len = env->GetStringLength(name);
650
651 if (len >= sizeof(buf)) {
652 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
653 if (utfName == NULL) {
654 throw_new(env, "java/lang/OutOfMemoryError");
655 goto free_body;
656 }
657 } else {
658 utfName = buf;
659 }
660
661 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
662
663 for (uint i = 0; i < len; i++) {
664 if (utfName[i] == '.') utfName[i] = '/';
665 }
666 }
667
668 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
669
670 if (utfName && utfName != buf) {
671 FREE_C_HEAP_ARRAY(char, utfName);
672 }
673
674 free_body:
675 FREE_C_HEAP_ARRAY(jbyte, body);
676 return result;
677 }
678
679
UNSAFE_ENTRY(jclass,Unsafe_DefineClass0 (JNIEnv * env,jobject unsafe,jstring name,jbyteArray data,int offset,int length,jobject loader,jobject pd))680 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
681 ThreadToNativeFromVM ttnfv(thread);
682
683 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
684 } UNSAFE_END
685
686
687 // define a class but do not make it known to the class loader or system dictionary
688 // - host_class: supplies context for linkage, access control, protection domain, and class loader
689 // if host_class is itself anonymous then it is replaced with its host class.
690 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
691 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
692
693 // When you load an anonymous class U, it works as if you changed its name just before loading,
694 // to a name that you will never use again. Since the name is lost, no other class can directly
695 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
696 // through java.lang.Class methods like Class.newInstance.
697
698 // The package of an anonymous class must either match its host's class's package or be in the
699 // unnamed package. If it is in the unnamed package then it will be put in its host class's
700 // package.
701 //
702
703 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
704 // An anonymous class also has special privileges to access any member of its host class.
705 // This is the main reason why this loading operation is unsafe. The purpose of this is to
706 // allow language implementations to simulate "open classes"; a host class in effect gets
707 // new code when an anonymous class is loaded alongside it. A less convenient but more
708 // standard way to do this is with reflection, which can also be set to ignore access
709 // restrictions.
710
711 // Access into an anonymous class is possible only through reflection. Therefore, there
712 // are no special access rules for calling into an anonymous class. The relaxed access
713 // rule for the host class is applied in the opposite direction: A host class reflectively
714 // access one of its anonymous classes.
715
716 // If you load the same bytecodes twice, you get two different classes. You can reload
717 // the same bytecodes with or without varying CP patches.
718
719 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
720 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
721 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
722
723 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
724 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
725 // It is not possible for a named class, or an older anonymous class, to refer by
726 // name (via its CP) to a newer anonymous class.
727
728 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
729 // or type descriptors used in the loaded anonymous class.
730
731 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
732 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
733 // be changed to println(greeting), where greeting is an arbitrary object created before
734 // the anonymous class is loaded. This is useful in dynamic languages, in which
735 // various kinds of metaobjects must be introduced as constants into bytecode.
736 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
737 // not just a literal string. For such ldc instructions, the verifier uses the
738 // type Object instead of String, if the loaded constant is not in fact a String.
739
740 static InstanceKlass*
Unsafe_DefineAnonymousClass_impl(JNIEnv * env,jclass host_class,jbyteArray data,jobjectArray cp_patches_jh,u1 ** temp_alloc,TRAPS)741 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
742 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
743 u1** temp_alloc,
744 TRAPS) {
745 assert(host_class != NULL, "host_class must not be NULL");
746 assert(data != NULL, "data must not be NULL");
747
748 if (UsePerfData) {
749 ClassLoader::unsafe_defineClassCallCounter()->inc();
750 }
751
752 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
753 assert(length >= 0, "class_bytes_length must not be negative: %d", length);
754
755 int class_bytes_length = (int) length;
756
757 u1* class_bytes = NEW_C_HEAP_ARRAY(u1, length, mtInternal);
758 if (class_bytes == NULL) {
759 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
760 }
761
762 // caller responsible to free it:
763 *temp_alloc = class_bytes;
764
765 ArrayAccess<>::arraycopy_to_native(arrayOop(JNIHandles::resolve_non_null(data)), typeArrayOopDesc::element_offset<jbyte>(0),
766 reinterpret_cast<jbyte*>(class_bytes), length);
767
768 objArrayHandle cp_patches_h;
769 if (cp_patches_jh != NULL) {
770 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
771 assert(p->is_objArray(), "cp_patches must be an object[]");
772 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
773 }
774
775 const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
776
777 // Make sure it's the real host class, not another anonymous class.
778 while (host_klass != NULL && host_klass->is_instance_klass() &&
779 InstanceKlass::cast(host_klass)->is_anonymous()) {
780 host_klass = InstanceKlass::cast(host_klass)->host_klass();
781 }
782
783 // Primitive types have NULL Klass* fields in their java.lang.Class instances.
784 if (host_klass == NULL) {
785 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
786 }
787
788 assert(host_klass->is_instance_klass(), "Host class must be an instance class");
789
790 const char* host_source = host_klass->external_name();
791 Handle host_loader(THREAD, host_klass->class_loader());
792 Handle host_domain(THREAD, host_klass->protection_domain());
793
794 GrowableArray<Handle>* cp_patches = NULL;
795
796 if (cp_patches_h.not_null()) {
797 int alen = cp_patches_h->length();
798
799 for (int i = alen-1; i >= 0; i--) {
800 oop p = cp_patches_h->obj_at(i);
801 if (p != NULL) {
802 Handle patch(THREAD, p);
803
804 if (cp_patches == NULL) {
805 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
806 }
807
808 cp_patches->at_put(i, patch);
809 }
810 }
811 }
812
813 ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
814
815 Symbol* no_class_name = NULL;
816 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
817 host_loader,
818 host_domain,
819 &st,
820 InstanceKlass::cast(host_klass),
821 cp_patches,
822 CHECK_NULL);
823 if (anonk == NULL) {
824 return NULL;
825 }
826
827 return InstanceKlass::cast(anonk);
828 }
829
UNSAFE_ENTRY(jclass,Unsafe_DefineAnonymousClass0 (JNIEnv * env,jobject unsafe,jclass host_class,jbyteArray data,jobjectArray cp_patches_jh))830 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
831 ResourceMark rm(THREAD);
832
833 jobject res_jh = NULL;
834 u1* temp_alloc = NULL;
835
836 InstanceKlass* anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
837 if (anon_klass != NULL) {
838 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
839 }
840
841 // try/finally clause:
842 if (temp_alloc != NULL) {
843 FREE_C_HEAP_ARRAY(u1, temp_alloc);
844 }
845
846 // The anonymous class loader data has been artificially been kept alive to
847 // this point. The mirror and any instances of this class have to keep
848 // it alive afterwards.
849 if (anon_klass != NULL) {
850 anon_klass->class_loader_data()->dec_keep_alive();
851 }
852
853 // let caller initialize it as needed...
854
855 return (jclass) res_jh;
856 } UNSAFE_END
857
858
859
UNSAFE_ENTRY(void,Unsafe_ThrowException (JNIEnv * env,jobject unsafe,jthrowable thr))860 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
861 ThreadToNativeFromVM ttnfv(thread);
862 env->Throw(thr);
863 } UNSAFE_END
864
865 // JSR166 ------------------------------------------------------------------
866
UNSAFE_ENTRY(jobject,Unsafe_CompareAndExchangeObject (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jobject e_h,jobject x_h))867 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
868 oop x = JNIHandles::resolve(x_h);
869 oop e = JNIHandles::resolve(e_h);
870 oop p = JNIHandles::resolve(obj);
871 assert_field_offset_sane(p, offset);
872 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
873 return JNIHandles::make_local(env, res);
874 } UNSAFE_END
875
UNSAFE_ENTRY(jint,Unsafe_CompareAndExchangeInt (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jint e,jint x))876 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
877 oop p = JNIHandles::resolve(obj);
878 if (p == NULL) {
879 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
880 return RawAccess<>::atomic_cmpxchg(x, addr, e);
881 } else {
882 assert_field_offset_sane(p, offset);
883 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
884 }
885 } UNSAFE_END
886
UNSAFE_ENTRY(jlong,Unsafe_CompareAndExchangeLong (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jlong e,jlong x))887 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
888 oop p = JNIHandles::resolve(obj);
889 if (p == NULL) {
890 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
891 return RawAccess<>::atomic_cmpxchg(x, addr, e);
892 } else {
893 assert_field_offset_sane(p, offset);
894 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
895 }
896 } UNSAFE_END
897
UNSAFE_ENTRY(jboolean,Unsafe_CompareAndSetObject (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jobject e_h,jobject x_h))898 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
899 oop x = JNIHandles::resolve(x_h);
900 oop e = JNIHandles::resolve(e_h);
901 oop p = JNIHandles::resolve(obj);
902 assert_field_offset_sane(p, offset);
903 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e);
904 return ret == e;
905 } UNSAFE_END
906
UNSAFE_ENTRY(jboolean,Unsafe_CompareAndSetInt (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jint e,jint x))907 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
908 oop p = JNIHandles::resolve(obj);
909 if (p == NULL) {
910 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
911 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
912 } else {
913 assert_field_offset_sane(p, offset);
914 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
915 }
916 } UNSAFE_END
917
UNSAFE_ENTRY(jboolean,Unsafe_CompareAndSetLong (JNIEnv * env,jobject unsafe,jobject obj,jlong offset,jlong e,jlong x))918 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
919 oop p = JNIHandles::resolve(obj);
920 if (p == NULL) {
921 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
922 return RawAccess<>::atomic_cmpxchg(x, addr, e) == e;
923 } else {
924 assert_field_offset_sane(p, offset);
925 return HeapAccess<>::atomic_cmpxchg_at(x, p, (ptrdiff_t)offset, e) == e;
926 }
927 } UNSAFE_END
928
post_thread_park_event(EventThreadPark * event,const oop obj,jlong timeout_nanos,jlong until_epoch_millis)929 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) {
930 assert(event != NULL, "invariant");
931 assert(event->should_commit(), "invariant");
932 event->set_parkedClass((obj != NULL) ? obj->klass() : NULL);
933 event->set_timeout(timeout_nanos);
934 event->set_until(until_epoch_millis);
935 event->set_address((obj != NULL) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
936 event->commit();
937 }
938
UNSAFE_ENTRY(void,Unsafe_Park (JNIEnv * env,jobject unsafe,jboolean isAbsolute,jlong time))939 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
940 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
941 EventThreadPark event;
942
943 JavaThreadParkedState jtps(thread, time != 0);
944 thread->parker()->park(isAbsolute != 0, time);
945 if (event.should_commit()) {
946 const oop obj = thread->current_park_blocker();
947 if (time == 0) {
948 post_thread_park_event(&event, obj, min_jlong, min_jlong);
949 } else {
950 if (isAbsolute != 0) {
951 post_thread_park_event(&event, obj, min_jlong, time);
952 } else {
953 post_thread_park_event(&event, obj, time, min_jlong);
954 }
955 }
956 }
957 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
958 } UNSAFE_END
959
UNSAFE_ENTRY(void,Unsafe_Unpark (JNIEnv * env,jobject unsafe,jobject jthread))960 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
961 Parker* p = NULL;
962
963 if (jthread != NULL) {
964 ThreadsListHandle tlh;
965 JavaThread* thr = NULL;
966 oop java_thread = NULL;
967 (void) tlh.cv_internal_thread_to_JavaThread(jthread, &thr, &java_thread);
968 if (java_thread != NULL) {
969 // This is a valid oop.
970 if (thr != NULL) {
971 // The JavaThread is alive.
972 p = thr->parker();
973 }
974 }
975 } // ThreadsListHandle is destroyed here.
976
977 // 'p' points to type-stable-memory if non-NULL. If the target
978 // thread terminates before we get here the new user of this
979 // Parker will get a 'spurious' unpark - which is perfectly valid.
980 if (p != NULL) {
981 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
982 p->unpark();
983 }
984 } UNSAFE_END
985
UNSAFE_ENTRY(jint,Unsafe_GetLoadAverage0 (JNIEnv * env,jobject unsafe,jdoubleArray loadavg,jint nelem))986 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
987 const int max_nelem = 3;
988 double la[max_nelem];
989 jint ret;
990
991 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
992 assert(a->is_typeArray(), "must be type array");
993
994 ret = os::loadavg(la, nelem);
995 if (ret == -1) {
996 return -1;
997 }
998
999 // if successful, ret is the number of samples actually retrieved.
1000 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1001 switch(ret) {
1002 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1003 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1004 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1005 }
1006
1007 return ret;
1008 } UNSAFE_END
1009
1010
1011 /// JVM_RegisterUnsafeMethods
1012
1013 #define ADR "J"
1014
1015 #define LANG "Ljava/lang/"
1016
1017 #define OBJ LANG "Object;"
1018 #define CLS LANG "Class;"
1019 #define FLD LANG "reflect/Field;"
1020 #define THR LANG "Throwable;"
1021
1022 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1023 #define DAC_Args CLS "[B[" OBJ
1024
1025 #define CC (char*) /*cast a literal from (const char*)*/
1026 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1027
1028 #define DECLARE_GETPUTOOP(Type, Desc) \
1029 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1030 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1031 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1032 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1033
1034
1035 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1036 {CC "getObject", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObject)},
1037 {CC "putObject", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObject)},
1038 {CC "getObjectVolatile",CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetObjectVolatile)},
1039 {CC "putObjectVolatile",CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutObjectVolatile)},
1040
1041 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1042
1043 DECLARE_GETPUTOOP(Boolean, Z),
1044 DECLARE_GETPUTOOP(Byte, B),
1045 DECLARE_GETPUTOOP(Short, S),
1046 DECLARE_GETPUTOOP(Char, C),
1047 DECLARE_GETPUTOOP(Int, I),
1048 DECLARE_GETPUTOOP(Long, J),
1049 DECLARE_GETPUTOOP(Float, F),
1050 DECLARE_GETPUTOOP(Double, D),
1051
1052 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1053 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1054 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1055
1056 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1057 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1058 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1059 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1060 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1061 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1062 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1063 {CC "addressSize0", CC "()I", FN_PTR(Unsafe_AddressSize0)},
1064 {CC "pageSize", CC "()I", FN_PTR(Unsafe_PageSize)},
1065
1066 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1067 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1068 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1069 {CC "compareAndSetObject",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetObject)},
1070 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1071 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1072 {CC "compareAndExchangeObject", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeObject)},
1073 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1074 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1075
1076 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1077 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1078
1079 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1080
1081 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1082 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1083 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1084
1085 {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1086
1087 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1088
1089 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1090 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1091 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1092
1093 {CC "isBigEndian0", CC "()Z", FN_PTR(Unsafe_isBigEndian0)},
1094 {CC "unalignedAccess0", CC "()Z", FN_PTR(Unsafe_unalignedAccess0)}
1095 };
1096
1097 #undef CC
1098 #undef FN_PTR
1099
1100 #undef ADR
1101 #undef LANG
1102 #undef OBJ
1103 #undef CLS
1104 #undef FLD
1105 #undef THR
1106 #undef DC_Args
1107 #undef DAC_Args
1108
1109 #undef DECLARE_GETPUTOOP
1110
1111
1112 // This function is exported, used by NativeLookup.
1113 // The Unsafe_xxx functions above are called only from the interpreter.
1114 // The optimizer looks at names and signatures to recognize
1115 // individual functions.
1116
JVM_ENTRY(void,JVM_RegisterJDKInternalMiscUnsafeMethods (JNIEnv * env,jclass unsafeclass))1117 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1118 ThreadToNativeFromVM ttnfv(thread);
1119
1120 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1121 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1122 } JVM_END
1123