1 /*
2 * Copyright (c) 2000, 2020, 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 "oops/access.inline.hpp"
35 #include "oops/fieldStreams.inline.hpp"
36 #include "oops/objArrayOop.inline.hpp"
37 #include "oops/oop.inline.hpp"
38 #include "oops/typeArrayOop.inline.hpp"
39 #include "prims/unsafe.hpp"
40 #include "runtime/globals.hpp"
41 #include "runtime/handles.inline.hpp"
42 #include "runtime/interfaceSupport.inline.hpp"
43 #include "runtime/jniHandles.inline.hpp"
44 #include "runtime/orderAccess.hpp"
45 #include "runtime/reflection.hpp"
46 #include "runtime/sharedRuntime.hpp"
47 #include "runtime/thread.hpp"
48 #include "runtime/threadSMR.hpp"
49 #include "runtime/vm_version.hpp"
50 #include "services/threadService.hpp"
51 #include "utilities/align.hpp"
52 #include "utilities/copy.hpp"
53 #include "utilities/dtrace.hpp"
54 #include "utilities/macros.hpp"
55 #if INCLUDE_TSAN
56 #include "tsan/tsanExternalDecls.hpp"
57 #endif
58
59 /**
60 * Implementation of the jdk.internal.misc.Unsafe class
61 */
62
63
64 #define MAX_OBJECT_SIZE \
65 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
66 + ((julong)max_jint * sizeof(double)) )
67
68
69 #define UNSAFE_ENTRY(result_type, header) \
70 JVM_ENTRY(static result_type, header)
71
72 #define UNSAFE_LEAF(result_type, header) \
73 JVM_LEAF(static result_type, header)
74
75 #define UNSAFE_END JVM_END
76
77
78 static inline void* addr_from_java(jlong addr) {
79 // This assert fails in a variety of ways on 32-bit systems.
80 // It is impossible to predict whether native code that converts
81 // pointers to longs will sign-extend or zero-extend the addresses.
82 //assert(addr == (uintptr_t)addr, "must not be odd high bits");
83 return (void*)(uintptr_t)addr;
84 }
85
86 static inline jlong addr_to_java(void* p) {
87 assert(p == (void*)(uintptr_t)p, "must not be odd high bits");
88 return (uintptr_t)p;
89 }
90
91
92 // Note: The VM's obj_field and related accessors use byte-scaled
93 // ("unscaled") offsets, just as the unsafe methods do.
94
95 // However, the method Unsafe.fieldOffset explicitly declines to
96 // guarantee this. The field offset values manipulated by the Java user
97 // through the Unsafe API are opaque cookies that just happen to be byte
98 // offsets. We represent this state of affairs by passing the cookies
99 // through conversion functions when going between the VM and the Unsafe API.
100 // The conversion functions just happen to be no-ops at present.
101
102 static inline jlong field_offset_to_byte_offset(jlong field_offset) {
103 return field_offset;
104 }
105
106 static inline jlong field_offset_from_byte_offset(jlong byte_offset) {
107 return byte_offset;
108 }
109
110 static inline void assert_field_offset_sane(oop p, jlong field_offset) {
111 #ifdef ASSERT
112 jlong byte_offset = field_offset_to_byte_offset(field_offset);
113
114 if (p != NULL) {
115 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
116 if (byte_offset == (jint)byte_offset) {
117 void* ptr_plus_disp = cast_from_oop<address>(p) + byte_offset;
118 assert(p->field_addr_raw((jint)byte_offset) == ptr_plus_disp,
119 "raw [ptr+disp] must be consistent with oop::field_addr_raw");
120 }
121 jlong p_size = HeapWordSize * (jlong)(p->size());
122 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size);
123 }
124 #endif
125 }
126
127 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
128 assert_field_offset_sane(p, field_offset);
129 jlong byte_offset = field_offset_to_byte_offset(field_offset);
130
131 if (p != NULL) {
132 p = Access<>::resolve(p);
133 }
134
135 if (sizeof(char*) == sizeof(jint)) { // (this constant folds!)
136 return cast_from_oop<address>(p) + (jint) byte_offset;
137 } else {
138 return cast_from_oop<address>(p) + byte_offset;
139 }
140 }
141
142 // Externally callable versions:
143 // (Use these in compiler intrinsics which emulate unsafe primitives.)
144 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
145 return field_offset;
146 }
147 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
148 return byte_offset;
149 }
150
151
152 ///// Data read/writes on the Java heap and in native (off-heap) memory
153
154 /**
155 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access()
156 */
157 class GuardUnsafeAccess {
158 JavaThread* _thread;
159
160 public:
161 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) {
162 // native/off-heap access which may raise SIGBUS if accessing
163 // memory mapped file data in a region of the file which has
164 // been truncated and is now invalid.
165 _thread->set_doing_unsafe_access(true);
166 }
167
168 ~GuardUnsafeAccess() {
169 _thread->set_doing_unsafe_access(false);
170 }
171 };
172
173 /**
174 * Helper class for accessing memory.
175 *
176 * Normalizes values and wraps accesses in
177 * JavaThread::doing_unsafe_access() if needed.
178 */
179 template <typename T>
180 class MemoryAccess : StackObj {
181 JavaThread* _thread;
182 oop _obj;
183 ptrdiff_t _offset;
184
185 // Resolves and returns the address of the memory access.
186 // This raw memory access may fault, so we make sure it happens within the
187 // guarded scope by making the access volatile at least. Since the store
188 // of Thread::set_doing_unsafe_access() is also volatile, these accesses
189 // can not be reordered by the compiler. Therefore, if the access triggers
190 // a fault, we will know that Thread::doing_unsafe_access() returns true.
191 volatile T* addr() {
192 void* addr = index_oop_from_field_offset_long(_obj, _offset);
193 return static_cast<volatile T*>(addr);
194 }
195
196 template <typename U>
197 U normalize_for_write(U x) {
198 return x;
199 }
200
201 jboolean normalize_for_write(jboolean x) {
202 return x & 1;
203 }
204
205 template <typename U>
206 U normalize_for_read(U x) {
207 return x;
208 }
209
210 jboolean normalize_for_read(jboolean x) {
211 return x != 0;
212 }
213
214 public:
215 MemoryAccess(JavaThread* thread, jobject obj, jlong offset)
216 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) {
217 assert_field_offset_sane(_obj, offset);
218 }
219
220 T get() {
221 if (_obj == NULL) {
222 GuardUnsafeAccess guard(_thread);
223 T ret = RawAccess<>::load(addr());
224 return normalize_for_read(ret);
225 } else {
226 T ret = HeapAccess<>::load_at(_obj, _offset);
227 return normalize_for_read(ret);
228 }
229 }
230
231 void put(T x) {
232 if (_obj == NULL) {
233 GuardUnsafeAccess guard(_thread);
234 RawAccess<>::store(addr(), normalize_for_write(x));
235 } else {
236 HeapAccess<>::store_at(_obj, _offset, normalize_for_write(x));
237 }
238 }
239
240
241 T get_volatile() {
242 if (_obj == NULL) {
243 GuardUnsafeAccess guard(_thread);
244 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr());
245 return normalize_for_read(ret);
246 } else {
247 T ret = HeapAccess<MO_SEQ_CST>::load_at(_obj, _offset);
248 return normalize_for_read(ret);
249 }
250 }
251
252 void put_volatile(T x) {
253 if (_obj == NULL) {
254 GuardUnsafeAccess guard(_thread);
255 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x));
256 } else {
257 HeapAccess<MO_SEQ_CST>::store_at(_obj, _offset, normalize_for_write(x));
258 }
259 }
260 };
261
262 // These functions allow a null base pointer with an arbitrary address.
263 // But if the base pointer is non-null, the offset should make some sense.
264 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
265 UNSAFE_ENTRY(jobject, Unsafe_GetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
266 oop p = JNIHandles::resolve(obj);
267 assert_field_offset_sane(p, offset);
268 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
269 TSAN_RUNTIME_ONLY(
270 void* addr = index_oop_from_field_offset_long(p, offset);
271 if (UseCompressedOops) {
272 __tsan_read4_pc(addr, SharedRuntime::tsan_code_location(0, 0));
273 } else {
274 __tsan_read8_pc(addr, SharedRuntime::tsan_code_location(0, 0));
275 }
276 );
277 return JNIHandles::make_local(env, v);
278 } UNSAFE_END
279
280 UNSAFE_ENTRY(void, Unsafe_PutReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
281 oop x = JNIHandles::resolve(x_h);
282 oop p = JNIHandles::resolve(obj);
283 assert_field_offset_sane(p, offset);
284 TSAN_RUNTIME_ONLY(
285 void* addr = index_oop_from_field_offset_long(p, offset);
286 if (UseCompressedOops) {
287 __tsan_write4_pc(addr, SharedRuntime::tsan_code_location(0, 0));
288 } else {
289 __tsan_write8_pc(addr, SharedRuntime::tsan_code_location(0, 0));
290 }
291 );
292 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
293 } UNSAFE_END
294
295 UNSAFE_ENTRY(jobject, Unsafe_GetReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) {
296 oop p = JNIHandles::resolve(obj);
297 assert_field_offset_sane(p, offset);
298 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset);
299 TSAN_RUNTIME_ONLY(
300 void* addr = index_oop_from_field_offset_long(p, offset);
301 __tsan_java_acquire(addr);
302 );
303 return JNIHandles::make_local(env, v);
304 } UNSAFE_END
305
306 UNSAFE_ENTRY(void, Unsafe_PutReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) {
307 oop x = JNIHandles::resolve(x_h);
308 oop p = JNIHandles::resolve(obj);
309 assert_field_offset_sane(p, offset);
310 TSAN_RUNTIME_ONLY(
311 void* addr = index_oop_from_field_offset_long(p, offset);
312 __tsan_java_release(addr);
313 );
314 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x);
315 } UNSAFE_END
316
317 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) {
318 oop v = *(oop*) (address) addr;
319 return JNIHandles::make_local(env, v);
320 } UNSAFE_END
321
322 #define DEFINE_GETSETOOP(java_type, Type, size) \
323 \
324 UNSAFE_ENTRY(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
325 java_type ret = MemoryAccess<java_type>(thread, obj, offset).get(); \
326 TSAN_RUNTIME_ONLY( \
327 void* addr = index_oop_from_field_offset_long(JNIHandles::resolve(obj), offset); \
328 __tsan_read##size##_pc(addr, SharedRuntime::tsan_code_location(0, 0)); \
329 ); \
330 return ret; \
331 } UNSAFE_END \
332 \
333 UNSAFE_ENTRY(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
334 TSAN_RUNTIME_ONLY( \
335 void* addr = index_oop_from_field_offset_long(JNIHandles::resolve(obj), offset); \
336 __tsan_write##size##_pc(addr, SharedRuntime::tsan_code_location(0, 0)); \
337 ); \
338 MemoryAccess<java_type>(thread, obj, offset).put(x); \
339 } UNSAFE_END \
340 \
341 // END DEFINE_GETSETOOP.
342
343 DEFINE_GETSETOOP(jboolean, Boolean, 1)
344 DEFINE_GETSETOOP(jbyte, Byte, 1)
345 DEFINE_GETSETOOP(jshort, Short, 2);
346 DEFINE_GETSETOOP(jchar, Char, 2);
347 DEFINE_GETSETOOP(jint, Int, 4);
348 DEFINE_GETSETOOP(jlong, Long, 8);
349 DEFINE_GETSETOOP(jfloat, Float, 4);
350 DEFINE_GETSETOOP(jdouble, Double, 8);
351
352 #undef DEFINE_GETSETOOP
353
354 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \
355 \
356 UNSAFE_ENTRY(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \
357 java_type ret = MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \
358 TSAN_RUNTIME_ONLY( \
359 void* addr = index_oop_from_field_offset_long(JNIHandles::resolve(obj), offset); \
360 __tsan_java_acquire(addr); \
361 ); \
362 return ret; \
363 } UNSAFE_END \
364 \
365 UNSAFE_ENTRY(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \
366 TSAN_RUNTIME_ONLY( \
367 void* addr = index_oop_from_field_offset_long(JNIHandles::resolve(obj), offset); \
368 __tsan_java_release(addr); \
369 ); \
370 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \
371 } UNSAFE_END \
372 \
373 // END DEFINE_GETSETOOP_VOLATILE.
374
375 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
376 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
377 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
378 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
379 DEFINE_GETSETOOP_VOLATILE(jint, Int);
380 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
381 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
382 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
383
384 #undef DEFINE_GETSETOOP_VOLATILE
385
386 UNSAFE_LEAF(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe)) {
387 OrderAccess::acquire();
388 } UNSAFE_END
389
390 UNSAFE_LEAF(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe)) {
391 OrderAccess::release();
392 } UNSAFE_END
393
394 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) {
395 OrderAccess::fence();
396 } UNSAFE_END
397
398 ////// Allocation requests
399
400 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) {
401 ThreadToNativeFromVM ttnfv(thread);
402 return env->AllocObject(cls);
403 } UNSAFE_END
404
405 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) {
406 size_t sz = (size_t)size;
407
408 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
409
410 void* x = os::malloc(sz, mtOther);
411
412 return addr_to_java(x);
413 } UNSAFE_END
414
415 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) {
416 void* p = addr_from_java(addr);
417 size_t sz = (size_t)size;
418
419 assert(is_aligned(sz, HeapWordSize), "sz not aligned");
420
421 void* x = os::realloc(p, sz, mtOther);
422
423 return addr_to_java(x);
424 } UNSAFE_END
425
426 UNSAFE_ENTRY(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) {
427 void* p = addr_from_java(addr);
428
429 os::free(p);
430 } UNSAFE_END
431
432 UNSAFE_ENTRY(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) {
433 size_t sz = (size_t)size;
434
435 oop base = JNIHandles::resolve(obj);
436 void* p = index_oop_from_field_offset_long(base, offset);
437
438 Copy::fill_to_memory_atomic(p, sz, value);
439 } UNSAFE_END
440
441 UNSAFE_ENTRY(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) {
442 size_t sz = (size_t)size;
443
444 oop srcp = JNIHandles::resolve(srcObj);
445 oop dstp = JNIHandles::resolve(dstObj);
446
447 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
448 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
449 {
450 GuardUnsafeAccess guard(thread);
451 if (StubRoutines::unsafe_arraycopy() != NULL) {
452 StubRoutines::UnsafeArrayCopy_stub()(src, dst, sz);
453 } else {
454 Copy::conjoint_memory_atomic(src, dst, sz);
455 }
456 }
457 } UNSAFE_END
458
459 // This function is a leaf since if the source and destination are both in native memory
460 // the copy may potentially be very large, and we don't want to disable GC if we can avoid it.
461 // If either source or destination (or both) are on the heap, the function will enter VM using
462 // JVM_ENTRY_FROM_LEAF
463 UNSAFE_LEAF(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) {
464 size_t sz = (size_t)size;
465 size_t esz = (size_t)elemSize;
466
467 if (srcObj == NULL && dstObj == NULL) {
468 // Both src & dst are in native memory
469 address src = (address)srcOffset;
470 address dst = (address)dstOffset;
471
472 {
473 JavaThread* thread = JavaThread::thread_from_jni_environment(env);
474 GuardUnsafeAccess guard(thread);
475 Copy::conjoint_swap(src, dst, sz, esz);
476 }
477 } else {
478 // At least one of src/dst are on heap, transition to VM to access raw pointers
479
480 JVM_ENTRY_FROM_LEAF(env, void, Unsafe_CopySwapMemory0) {
481 oop srcp = JNIHandles::resolve(srcObj);
482 oop dstp = JNIHandles::resolve(dstObj);
483
484 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset);
485 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset);
486
487 {
488 GuardUnsafeAccess guard(thread);
489 Copy::conjoint_swap(src, dst, sz, esz);
490 }
491 } JVM_END
492 }
493 } UNSAFE_END
494
495 UNSAFE_LEAF (void, Unsafe_WriteBack0(JNIEnv *env, jobject unsafe, jlong line)) {
496 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
497 #ifdef ASSERT
498 if (TraceMemoryWriteback) {
499 tty->print_cr("Unsafe: writeback 0x%p", addr_from_java(line));
500 }
501 #endif
502
503 assert(StubRoutines::data_cache_writeback() != NULL, "sanity");
504 (StubRoutines::DataCacheWriteback_stub())(addr_from_java(line));
505 } UNSAFE_END
506
507 static void doWriteBackSync0(bool is_pre)
508 {
509 assert(StubRoutines::data_cache_writeback_sync() != NULL, "sanity");
510 (StubRoutines::DataCacheWritebackSync_stub())(is_pre);
511 }
512
513 UNSAFE_LEAF (void, Unsafe_WriteBackPreSync0(JNIEnv *env, jobject unsafe)) {
514 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
515 #ifdef ASSERT
516 if (TraceMemoryWriteback) {
517 tty->print_cr("Unsafe: writeback pre-sync");
518 }
519 #endif
520
521 doWriteBackSync0(true);
522 } UNSAFE_END
523
524 UNSAFE_LEAF (void, Unsafe_WriteBackPostSync0(JNIEnv *env, jobject unsafe)) {
525 assert(VM_Version::supports_data_cache_line_flush(), "should not get here");
526 #ifdef ASSERT
527 if (TraceMemoryWriteback) {
528 tty->print_cr("Unsafe: writeback pre-sync");
529 }
530 #endif
531
532 doWriteBackSync0(false);
533 } UNSAFE_END
534
535 ////// Random queries
536
537 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) {
538 assert(clazz != NULL, "clazz must not be NULL");
539 assert(name != NULL, "name must not be NULL");
540
541 ResourceMark rm(THREAD);
542 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name));
543
544 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz)));
545
546 jint offset = -1;
547 for (JavaFieldStream fs(k); !fs.done(); fs.next()) {
548 Symbol *name = fs.name();
549 if (name->equals(utf_name)) {
550 offset = fs.offset();
551 break;
552 }
553 }
554 if (offset < 0) {
555 THROW_0(vmSymbols::java_lang_InternalError());
556 }
557 return field_offset_from_byte_offset(offset);
558 }
559
560 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) {
561 assert(field != NULL, "field must not be NULL");
562
563 oop reflected = JNIHandles::resolve_non_null(field);
564 oop mirror = java_lang_reflect_Field::clazz(reflected);
565 Klass* k = java_lang_Class::as_Klass(mirror);
566 int slot = java_lang_reflect_Field::slot(reflected);
567 int modifiers = java_lang_reflect_Field::modifiers(reflected);
568
569 if (must_be_static >= 0) {
570 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
571 if (must_be_static != really_is_static) {
572 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
573 }
574 }
575
576 int offset = InstanceKlass::cast(k)->field_offset(slot);
577 return field_offset_from_byte_offset(offset);
578 }
579
580 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
581 return find_field_offset(field, 0, THREAD);
582 } UNSAFE_END
583
584 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) {
585 return find_field_offset(c, name, THREAD);
586 } UNSAFE_END
587
588 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) {
589 return find_field_offset(field, 1, THREAD);
590 } UNSAFE_END
591
592 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) {
593 assert(field != NULL, "field must not be NULL");
594
595 // Note: In this VM implementation, a field address is always a short
596 // offset from the base of a a klass metaobject. Thus, the full dynamic
597 // range of the return type is never used. However, some implementations
598 // might put the static field inside an array shared by many classes,
599 // or even at a fixed address, in which case the address could be quite
600 // large. In that last case, this function would return NULL, since
601 // the address would operate alone, without any base pointer.
602
603 oop reflected = JNIHandles::resolve_non_null(field);
604 oop mirror = java_lang_reflect_Field::clazz(reflected);
605 int modifiers = java_lang_reflect_Field::modifiers(reflected);
606
607 if ((modifiers & JVM_ACC_STATIC) == 0) {
608 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
609 }
610
611 return JNIHandles::make_local(env, mirror);
612 } UNSAFE_END
613
614 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
615 assert(clazz != NULL, "clazz must not be NULL");
616
617 oop mirror = JNIHandles::resolve_non_null(clazz);
618
619 Klass* klass = java_lang_Class::as_Klass(mirror);
620 if (klass != NULL && klass->should_be_initialized()) {
621 InstanceKlass* k = InstanceKlass::cast(klass);
622 k->initialize(CHECK);
623 }
624 }
625 UNSAFE_END
626
627 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) {
628 assert(clazz != NULL, "clazz must not be NULL");
629
630 oop mirror = JNIHandles::resolve_non_null(clazz);
631 Klass* klass = java_lang_Class::as_Klass(mirror);
632
633 if (klass != NULL && klass->should_be_initialized()) {
634 return true;
635 }
636
637 return false;
638 }
639 UNSAFE_END
640
641 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) {
642 assert(clazz != NULL, "clazz must not be NULL");
643
644 oop mirror = JNIHandles::resolve_non_null(clazz);
645 Klass* k = java_lang_Class::as_Klass(mirror);
646
647 if (k == NULL || !k->is_array_klass()) {
648 THROW(vmSymbols::java_lang_InvalidClassException());
649 } else if (k->is_objArray_klass()) {
650 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
651 scale = heapOopSize;
652 } else if (k->is_typeArray_klass()) {
653 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
654 base = tak->array_header_in_bytes();
655 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
656 scale = (1 << tak->log2_element_size());
657 } else {
658 ShouldNotReachHere();
659 }
660 }
661
662 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) {
663 int base = 0, scale = 0;
664 getBaseAndScale(base, scale, clazz, CHECK_0);
665
666 return field_offset_from_byte_offset(base);
667 } UNSAFE_END
668
669
670 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) {
671 int base = 0, scale = 0;
672 getBaseAndScale(base, scale, clazz, CHECK_0);
673
674 // This VM packs both fields and array elements down to the byte.
675 // But watch out: If this changes, so that array references for
676 // a given primitive type (say, T_BOOLEAN) use different memory units
677 // than fields, this method MUST return zero for such arrays.
678 // For example, the VM used to store sub-word sized fields in full
679 // words in the object layout, so that accessors like getByte(Object,int)
680 // did not really do what one might expect for arrays. Therefore,
681 // this function used to report a zero scale factor, so that the user
682 // would know not to attempt to access sub-word array elements.
683 // // Code for unpacked fields:
684 // if (scale < wordSize) return 0;
685
686 // The following allows for a pretty general fieldOffset cookie scheme,
687 // but requires it to be linear in byte offset.
688 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
689 } UNSAFE_END
690
691
692 static inline void throw_new(JNIEnv *env, const char *ename) {
693 jclass cls = env->FindClass(ename);
694 if (env->ExceptionCheck()) {
695 env->ExceptionClear();
696 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename);
697 return;
698 }
699
700 env->ThrowNew(cls, NULL);
701 }
702
703 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
704 // Code lifted from JDK 1.3 ClassLoader.c
705
706 jbyte *body;
707 char *utfName = NULL;
708 jclass result = 0;
709 char buf[128];
710
711 assert(data != NULL, "Class bytes must not be NULL");
712 assert(length >= 0, "length must not be negative: %d", length);
713
714 if (UsePerfData) {
715 ClassLoader::unsafe_defineClassCallCounter()->inc();
716 }
717
718 body = NEW_C_HEAP_ARRAY_RETURN_NULL(jbyte, length, mtInternal);
719 if (body == NULL) {
720 throw_new(env, "java/lang/OutOfMemoryError");
721 return 0;
722 }
723
724 env->GetByteArrayRegion(data, offset, length, body);
725 if (env->ExceptionOccurred()) {
726 goto free_body;
727 }
728
729 if (name != NULL) {
730 uint len = env->GetStringUTFLength(name);
731 int unicode_len = env->GetStringLength(name);
732
733 if (len >= sizeof(buf)) {
734 utfName = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len + 1, mtInternal);
735 if (utfName == NULL) {
736 throw_new(env, "java/lang/OutOfMemoryError");
737 goto free_body;
738 }
739 } else {
740 utfName = buf;
741 }
742
743 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
744
745 for (uint i = 0; i < len; i++) {
746 if (utfName[i] == '.') utfName[i] = '/';
747 }
748 }
749
750 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
751
752 if (utfName && utfName != buf) {
753 FREE_C_HEAP_ARRAY(char, utfName);
754 }
755
756 free_body:
757 FREE_C_HEAP_ARRAY(jbyte, body);
758 return result;
759 }
760
761
762 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) {
763 ThreadToNativeFromVM ttnfv(thread);
764
765 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
766 } UNSAFE_END
767
768
769 // define a class but do not make it known to the class loader or system dictionary
770 // - host_class: supplies context for linkage, access control, protection domain, and class loader
771 // if host_class is itself anonymous then it is replaced with its host class.
772 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
773 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
774
775 // When you load an anonymous class U, it works as if you changed its name just before loading,
776 // to a name that you will never use again. Since the name is lost, no other class can directly
777 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
778 // through java.lang.Class methods like Class.newInstance.
779
780 // The package of an anonymous class must either match its host's class's package or be in the
781 // unnamed package. If it is in the unnamed package then it will be put in its host class's
782 // package.
783 //
784
785 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
786 // An anonymous class also has special privileges to access any member of its host class.
787 // This is the main reason why this loading operation is unsafe. The purpose of this is to
788 // allow language implementations to simulate "open classes"; a host class in effect gets
789 // new code when an anonymous class is loaded alongside it. A less convenient but more
790 // standard way to do this is with reflection, which can also be set to ignore access
791 // restrictions.
792
793 // Access into an anonymous class is possible only through reflection. Therefore, there
794 // are no special access rules for calling into an anonymous class. The relaxed access
795 // rule for the host class is applied in the opposite direction: A host class reflectively
796 // access one of its anonymous classes.
797
798 // If you load the same bytecodes twice, you get two different classes. You can reload
799 // the same bytecodes with or without varying CP patches.
800
801 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
802 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
803 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
804
805 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
806 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
807 // It is not possible for a named class, or an older anonymous class, to refer by
808 // name (via its CP) to a newer anonymous class.
809
810 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
811 // or type descriptors used in the loaded anonymous class.
812
813 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
814 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
815 // be changed to println(greeting), where greeting is an arbitrary object created before
816 // the anonymous class is loaded. This is useful in dynamic languages, in which
817 // various kinds of metaobjects must be introduced as constants into bytecode.
818 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
819 // not just a literal string. For such ldc instructions, the verifier uses the
820 // type Object instead of String, if the loaded constant is not in fact a String.
821
822 static InstanceKlass*
823 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
824 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
825 u1** temp_alloc,
826 TRAPS) {
827 assert(host_class != NULL, "host_class must not be NULL");
828 assert(data != NULL, "data must not be NULL");
829
830 if (UsePerfData) {
831 ClassLoader::unsafe_defineClassCallCounter()->inc();
832 }
833
834 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
835 assert(length >= 0, "class_bytes_length must not be negative: %d", length);
836
837 int class_bytes_length = (int) length;
838
839 u1* class_bytes = NEW_C_HEAP_ARRAY_RETURN_NULL(u1, length, mtInternal);
840 if (class_bytes == NULL) {
841 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
842 }
843
844 // caller responsible to free it:
845 *temp_alloc = class_bytes;
846
847 ArrayAccess<>::arraycopy_to_native(arrayOop(JNIHandles::resolve_non_null(data)), typeArrayOopDesc::element_offset<jbyte>(0),
848 reinterpret_cast<jbyte*>(class_bytes), length);
849
850 objArrayHandle cp_patches_h;
851 if (cp_patches_jh != NULL) {
852 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
853 assert(p->is_objArray(), "cp_patches must be an object[]");
854 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
855 }
856
857 const Klass* host_klass = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class));
858
859 // Make sure it's the real host class, not another anonymous class.
860 while (host_klass != NULL && host_klass->is_instance_klass() &&
861 InstanceKlass::cast(host_klass)->is_unsafe_anonymous()) {
862 host_klass = InstanceKlass::cast(host_klass)->unsafe_anonymous_host();
863 }
864
865 // Primitive types have NULL Klass* fields in their java.lang.Class instances.
866 if (host_klass == NULL) {
867 THROW_MSG_0(vmSymbols::java_lang_IllegalArgumentException(), "Host class is null");
868 }
869
870 assert(host_klass->is_instance_klass(), "Host class must be an instance class");
871
872 const char* host_source = host_klass->external_name();
873 Handle host_loader(THREAD, host_klass->class_loader());
874 Handle host_domain(THREAD, host_klass->protection_domain());
875
876 GrowableArray<Handle>* cp_patches = NULL;
877
878 if (cp_patches_h.not_null()) {
879 int alen = cp_patches_h->length();
880
881 for (int i = alen-1; i >= 0; i--) {
882 oop p = cp_patches_h->obj_at(i);
883 if (p != NULL) {
884 Handle patch(THREAD, p);
885
886 if (cp_patches == NULL) {
887 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
888 }
889
890 cp_patches->at_put(i, patch);
891 }
892 }
893 }
894
895 ClassFileStream st(class_bytes, class_bytes_length, host_source, ClassFileStream::verify);
896
897 Symbol* no_class_name = NULL;
898 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
899 host_loader,
900 host_domain,
901 &st,
902 InstanceKlass::cast(host_klass),
903 cp_patches,
904 CHECK_NULL);
905 if (anonk == NULL) {
906 return NULL;
907 }
908
909 return InstanceKlass::cast(anonk);
910 }
911
912 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass0(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh)) {
913 ResourceMark rm(THREAD);
914
915 jobject res_jh = NULL;
916 u1* temp_alloc = NULL;
917
918 InstanceKlass* anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data, cp_patches_jh, &temp_alloc, THREAD);
919 if (anon_klass != NULL) {
920 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
921 }
922
923 // try/finally clause:
924 FREE_C_HEAP_ARRAY(u1, temp_alloc);
925
926 // The anonymous class loader data has been artificially been kept alive to
927 // this point. The mirror and any instances of this class have to keep
928 // it alive afterwards.
929 if (anon_klass != NULL) {
930 anon_klass->class_loader_data()->dec_keep_alive();
931 }
932
933 // let caller initialize it as needed...
934
935 return (jclass) res_jh;
936 } UNSAFE_END
937
938
939
940 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) {
941 ThreadToNativeFromVM ttnfv(thread);
942 env->Throw(thr);
943 } UNSAFE_END
944
945 // JSR166 ------------------------------------------------------------------
946
947 // Calls __tsan_java_release() on construct and __tsan_java_acquire() on destruct.
948 class ScopedReleaseAcquire: public StackObj {
949 private:
950 void* _addr;
951 public:
952 ScopedReleaseAcquire(volatile void* addr) {
953 TSAN_RUNTIME_ONLY(
954 _addr = const_cast<void*>(addr);
955 __tsan_java_release(_addr);
956 );
957 }
958
959 ScopedReleaseAcquire(oop obj, jlong offset) {
960 TSAN_RUNTIME_ONLY(
961 _addr = index_oop_from_field_offset_long(obj, offset);
962 __tsan_java_release(_addr);
963 );
964 }
965
966 ~ScopedReleaseAcquire() {
967 TSAN_RUNTIME_ONLY(__tsan_java_acquire(_addr));
968 }
969 };
970
971 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
972 oop x = JNIHandles::resolve(x_h);
973 oop e = JNIHandles::resolve(e_h);
974 oop p = JNIHandles::resolve(obj);
975 assert_field_offset_sane(p, offset);
976 ScopedReleaseAcquire releaseAcquire(p, offset);
977 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
978 return JNIHandles::make_local(env, res);
979 } UNSAFE_END
980
981 UNSAFE_ENTRY(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
982 oop p = JNIHandles::resolve(obj);
983 if (p == NULL) {
984 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
985 ScopedReleaseAcquire releaseAcquire(addr);
986 return RawAccess<>::atomic_cmpxchg(addr, e, x);
987 } else {
988 assert_field_offset_sane(p, offset);
989 ScopedReleaseAcquire releaseAcquire(p, offset);
990 return HeapAccess<>::atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
991 }
992 } UNSAFE_END
993
994 UNSAFE_ENTRY(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
995 oop p = JNIHandles::resolve(obj);
996 if (p == NULL) {
997 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
998 ScopedReleaseAcquire releaseAcquire(addr);
999 return RawAccess<>::atomic_cmpxchg(addr, e, x);
1000 } else {
1001 assert_field_offset_sane(p, offset);
1002 ScopedReleaseAcquire releaseAcquire(p, offset);
1003 return HeapAccess<>::atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
1004 }
1005 } UNSAFE_END
1006
1007 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) {
1008 oop x = JNIHandles::resolve(x_h);
1009 oop e = JNIHandles::resolve(e_h);
1010 oop p = JNIHandles::resolve(obj);
1011 assert_field_offset_sane(p, offset);
1012 ScopedReleaseAcquire releaseAcquire(p, offset);
1013 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x);
1014 return ret == e;
1015 } UNSAFE_END
1016
1017 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) {
1018 oop p = JNIHandles::resolve(obj);
1019 if (p == NULL) {
1020 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset);
1021 ScopedReleaseAcquire releaseAcquire(addr);
1022 return RawAccess<>::atomic_cmpxchg(addr, e, x) == e;
1023 } else {
1024 assert_field_offset_sane(p, offset);
1025 ScopedReleaseAcquire releaseAcquire(p, offset);
1026 return HeapAccess<>::atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x) == e;
1027 }
1028 } UNSAFE_END
1029
1030 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) {
1031 oop p = JNIHandles::resolve(obj);
1032 if (p == NULL) {
1033 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset);
1034 ScopedReleaseAcquire releaseAcquire(addr);
1035 return RawAccess<>::atomic_cmpxchg(addr, e, x) == e;
1036 } else {
1037 assert_field_offset_sane(p, offset);
1038 ScopedReleaseAcquire releaseAcquire(p, offset);
1039 return HeapAccess<>::atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x) == e;
1040 }
1041 } UNSAFE_END
1042
1043 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) {
1044 assert(event != NULL, "invariant");
1045 assert(event->should_commit(), "invariant");
1046 event->set_parkedClass((obj != NULL) ? obj->klass() : NULL);
1047 event->set_timeout(timeout_nanos);
1048 event->set_until(until_epoch_millis);
1049 event->set_address((obj != NULL) ? (u8)cast_from_oop<uintptr_t>(obj) : 0);
1050 event->commit();
1051 }
1052
1053 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) {
1054 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1055 EventThreadPark event;
1056
1057 JavaThreadParkedState jtps(thread, time != 0);
1058 thread->parker()->park(isAbsolute != 0, time);
1059 if (event.should_commit()) {
1060 const oop obj = thread->current_park_blocker();
1061 if (time == 0) {
1062 post_thread_park_event(&event, obj, min_jlong, min_jlong);
1063 } else {
1064 if (isAbsolute != 0) {
1065 post_thread_park_event(&event, obj, min_jlong, time);
1066 } else {
1067 post_thread_park_event(&event, obj, time, min_jlong);
1068 }
1069 }
1070 }
1071 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1072 } UNSAFE_END
1073
1074 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) {
1075 Parker* p = NULL;
1076
1077 if (jthread != NULL) {
1078 ThreadsListHandle tlh;
1079 JavaThread* thr = NULL;
1080 oop java_thread = NULL;
1081 (void) tlh.cv_internal_thread_to_JavaThread(jthread, &thr, &java_thread);
1082 if (java_thread != NULL) {
1083 // This is a valid oop.
1084 if (thr != NULL) {
1085 // The JavaThread is alive.
1086 p = thr->parker();
1087 }
1088 }
1089 } // ThreadsListHandle is destroyed here.
1090
1091 // 'p' points to type-stable-memory if non-NULL. If the target
1092 // thread terminates before we get here the new user of this
1093 // Parker will get a 'spurious' unpark - which is perfectly valid.
1094 if (p != NULL) {
1095 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1096 p->unpark();
1097 }
1098 } UNSAFE_END
1099
1100 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) {
1101 const int max_nelem = 3;
1102 double la[max_nelem];
1103 jint ret;
1104
1105 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1106 assert(a->is_typeArray(), "must be type array");
1107
1108 ret = os::loadavg(la, nelem);
1109 if (ret == -1) {
1110 return -1;
1111 }
1112
1113 // if successful, ret is the number of samples actually retrieved.
1114 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1115 switch(ret) {
1116 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1117 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1118 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1119 }
1120
1121 return ret;
1122 } UNSAFE_END
1123
1124
1125 /// JVM_RegisterUnsafeMethods
1126
1127 #define ADR "J"
1128
1129 #define LANG "Ljava/lang/"
1130
1131 #define OBJ LANG "Object;"
1132 #define CLS LANG "Class;"
1133 #define FLD LANG "reflect/Field;"
1134 #define THR LANG "Throwable;"
1135
1136 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;"
1137 #define DAC_Args CLS "[B[" OBJ
1138
1139 #define CC (char*) /*cast a literal from (const char*)*/
1140 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1141
1142 #define DECLARE_GETPUTOOP(Type, Desc) \
1143 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \
1144 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \
1145 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \
1146 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)}
1147
1148
1149 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = {
1150 {CC "getReference", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetReference)},
1151 {CC "putReference", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReference)},
1152 {CC "getReferenceVolatile", CC "(" OBJ "J)" OBJ, FN_PTR(Unsafe_GetReferenceVolatile)},
1153 {CC "putReferenceVolatile", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReferenceVolatile)},
1154
1155 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)},
1156
1157 DECLARE_GETPUTOOP(Boolean, Z),
1158 DECLARE_GETPUTOOP(Byte, B),
1159 DECLARE_GETPUTOOP(Short, S),
1160 DECLARE_GETPUTOOP(Char, C),
1161 DECLARE_GETPUTOOP(Int, I),
1162 DECLARE_GETPUTOOP(Long, J),
1163 DECLARE_GETPUTOOP(Float, F),
1164 DECLARE_GETPUTOOP(Double, D),
1165
1166 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)},
1167 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)},
1168 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)},
1169
1170 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)},
1171 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)},
1172 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)},
1173 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)},
1174 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)},
1175 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)},
1176 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)},
1177
1178 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)},
1179 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)},
1180 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)},
1181 {CC "compareAndSetReference",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetReference)},
1182 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)},
1183 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)},
1184 {CC "compareAndExchangeReference", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeReference)},
1185 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)},
1186 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)},
1187
1188 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)},
1189 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)},
1190
1191 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)},
1192
1193 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)},
1194 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)},
1195 {CC "writeback0", CC "(" "J" ")V", FN_PTR(Unsafe_WriteBack0)},
1196 {CC "writebackPreSync0", CC "()V", FN_PTR(Unsafe_WriteBackPreSync0)},
1197 {CC "writebackPostSync0", CC "()V", FN_PTR(Unsafe_WriteBackPostSync0)},
1198 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)},
1199
1200 {CC "defineAnonymousClass0", CC "(" DAC_Args ")" CLS, FN_PTR(Unsafe_DefineAnonymousClass0)},
1201
1202 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)},
1203
1204 {CC "loadFence", CC "()V", FN_PTR(Unsafe_LoadFence)},
1205 {CC "storeFence", CC "()V", FN_PTR(Unsafe_StoreFence)},
1206 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)},
1207 };
1208
1209 #undef CC
1210 #undef FN_PTR
1211
1212 #undef ADR
1213 #undef LANG
1214 #undef OBJ
1215 #undef CLS
1216 #undef FLD
1217 #undef THR
1218 #undef DC_Args
1219 #undef DAC_Args
1220
1221 #undef DECLARE_GETPUTOOP
1222
1223
1224 // This function is exported, used by NativeLookup.
1225 // The Unsafe_xxx functions above are called only from the interpreter.
1226 // The optimizer looks at names and signatures to recognize
1227 // individual functions.
1228
1229 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) {
1230 ThreadToNativeFromVM ttnfv(thread);
1231
1232 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod));
1233 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives");
1234 } JVM_END