1 /*
2 * Copyright (c) 2000, 2015, 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 "classfile/vmSymbols.hpp"
27 #include "memory/allocation.inline.hpp"
28 #include "oops/objArrayOop.inline.hpp"
29 #include "oops/oop.inline.hpp"
30 #include "prims/jni.h"
31 #include "prims/jvm.h"
32 #include "runtime/atomic.inline.hpp"
33 #include "runtime/globals.hpp"
34 #include "runtime/interfaceSupport.hpp"
35 #include "runtime/orderAccess.inline.hpp"
36 #include "runtime/reflection.hpp"
37 #include "runtime/vm_version.hpp"
38 #include "services/threadService.hpp"
39 #include "trace/tracing.hpp"
40 #include "utilities/copy.hpp"
41 #include "utilities/dtrace.hpp"
42 #include "utilities/macros.hpp"
43 #if INCLUDE_ALL_GCS
44 #include "gc_implementation/g1/g1SATBCardTableModRefBS.hpp"
45 #endif // INCLUDE_ALL_GCS
46
47 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
48
49 /*
50 * Implementation of class sun.misc.Unsafe
51 */
52
53
54 #define MAX_OBJECT_SIZE \
55 ( arrayOopDesc::header_size(T_DOUBLE) * HeapWordSize \
56 + ((julong)max_jint * sizeof(double)) )
57
58
59 #define UNSAFE_ENTRY(result_type, header) \
60 JVM_ENTRY(result_type, header)
61
62 // Can't use UNSAFE_LEAF because it has the signature of a straight
63 // call into the runtime (just like JVM_LEAF, funny that) but it's
64 // called like a Java Native and thus the wrapper built for it passes
65 // arguments like a JNI call. It expects those arguments to be popped
66 // from the stack on Intel like all good JNI args are, and adjusts the
67 // stack according. Since the JVM_LEAF call expects no extra
68 // arguments the stack isn't popped in the C code, is pushed by the
69 // wrapper and we get sick.
70 //#define UNSAFE_LEAF(result_type, header) \
71 // JVM_LEAF(result_type, header)
72
73 #define UNSAFE_END JVM_END
74
75 #define UnsafeWrapper(arg) /*nothing, for the present*/
76
77
78 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 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 inline jlong field_offset_to_byte_offset(jlong field_offset) {
103 return field_offset;
104 }
105
106 inline jlong field_offset_from_byte_offset(jlong byte_offset) {
107 return byte_offset;
108 }
109
110 inline jint invocation_key_from_method_slot(jint slot) {
111 return slot;
112 }
113
114 inline jint invocation_key_to_method_slot(jint key) {
115 return key;
116 }
117
118 inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) {
119 jlong byte_offset = field_offset_to_byte_offset(field_offset);
120 #ifdef ASSERT
121 if (p != NULL) {
122 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset");
123 if (byte_offset == (jint)byte_offset) {
124 void* ptr_plus_disp = (address)p + byte_offset;
125 assert((void*)p->obj_field_addr<oop>((jint)byte_offset) == ptr_plus_disp,
126 "raw [ptr+disp] must be consistent with oop::field_base");
127 }
128 jlong p_size = HeapWordSize * (jlong)(p->size());
129 assert(byte_offset < p_size, err_msg("Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, byte_offset, p_size));
130 }
131 #endif
132 if (sizeof(char*) == sizeof(jint)) // (this constant folds!)
133 return (address)p + (jint) byte_offset;
134 else
135 return (address)p + byte_offset;
136 }
137
138 // Externally callable versions:
139 // (Use these in compiler intrinsics which emulate unsafe primitives.)
140 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) {
141 return field_offset;
142 }
143 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) {
144 return byte_offset;
145 }
146 jint Unsafe_invocation_key_from_method_slot(jint slot) {
147 return invocation_key_from_method_slot(slot);
148 }
149 jint Unsafe_invocation_key_to_method_slot(jint key) {
150 return invocation_key_to_method_slot(key);
151 }
152
153
154 ///// Data in the Java heap.
155
156 #define GET_FIELD(obj, offset, type_name, v) \
157 oop p = JNIHandles::resolve(obj); \
158 type_name v = *(type_name*)index_oop_from_field_offset_long(p, offset)
159
160 #define SET_FIELD(obj, offset, type_name, x) \
161 oop p = JNIHandles::resolve(obj); \
162 *(type_name*)index_oop_from_field_offset_long(p, offset) = x
163
164 #define GET_FIELD_VOLATILE(obj, offset, type_name, v) \
165 oop p = JNIHandles::resolve(obj); \
166 if (support_IRIW_for_not_multiple_copy_atomic_cpu) { \
167 OrderAccess::fence(); \
168 } \
169 volatile type_name v = OrderAccess::load_acquire((volatile type_name*)index_oop_from_field_offset_long(p, offset));
170
171 #define SET_FIELD_VOLATILE(obj, offset, type_name, x) \
172 oop p = JNIHandles::resolve(obj); \
173 OrderAccess::release_store_fence((volatile type_name*)index_oop_from_field_offset_long(p, offset), x);
174
175 // Macros for oops that check UseCompressedOops
176
177 #define GET_OOP_FIELD(obj, offset, v) \
178 oop p = JNIHandles::resolve(obj); \
179 oop v; \
180 if (UseCompressedOops) { \
181 narrowOop n = *(narrowOop*)index_oop_from_field_offset_long(p, offset); \
182 v = oopDesc::decode_heap_oop(n); \
183 } else { \
184 v = *(oop*)index_oop_from_field_offset_long(p, offset); \
185 }
186
187
188 // Get/SetObject must be special-cased, since it works with handles.
189
190 // These functions allow a null base pointer with an arbitrary address.
191 // But if the base pointer is non-null, the offset should make some sense.
192 // That is, it should be in the range [0, MAX_OBJECT_SIZE].
193 UNSAFE_ENTRY(jobject, Unsafe_GetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
194 UnsafeWrapper("Unsafe_GetObject");
195 GET_OOP_FIELD(obj, offset, v)
196 jobject ret = JNIHandles::make_local(env, v);
197 #if INCLUDE_ALL_GCS
198 // We could be accessing the referent field in a reference
199 // object. If G1 is enabled then we need to register non-null
200 // referent with the SATB barrier.
201 if (UseG1GC) {
202 bool needs_barrier = false;
203
204 if (ret != NULL) {
205 if (offset == java_lang_ref_Reference::referent_offset && obj != NULL) {
206 oop o = JNIHandles::resolve(obj);
207 Klass* k = o->klass();
208 if (InstanceKlass::cast(k)->reference_type() != REF_NONE) {
209 assert(InstanceKlass::cast(k)->is_subclass_of(SystemDictionary::Reference_klass()), "sanity");
210 needs_barrier = true;
211 }
212 }
213 }
214
215 if (needs_barrier) {
216 oop referent = JNIHandles::resolve(ret);
217 G1SATBCardTableModRefBS::enqueue(referent);
218 }
219 }
220 #endif // INCLUDE_ALL_GCS
221 return ret;
222 UNSAFE_END
223
224 UNSAFE_ENTRY(void, Unsafe_SetObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
225 UnsafeWrapper("Unsafe_SetObject");
226 oop x = JNIHandles::resolve(x_h);
227 oop p = JNIHandles::resolve(obj);
228 if (UseCompressedOops) {
229 oop_store((narrowOop*)index_oop_from_field_offset_long(p, offset), x);
230 } else {
231 oop_store((oop*)index_oop_from_field_offset_long(p, offset), x);
232 }
233 UNSAFE_END
234
235 UNSAFE_ENTRY(jobject, Unsafe_GetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
236 UnsafeWrapper("Unsafe_GetObjectVolatile");
237 oop p = JNIHandles::resolve(obj);
238 void* addr = index_oop_from_field_offset_long(p, offset);
239 volatile oop v;
240 if (UseCompressedOops) {
241 volatile narrowOop n = *(volatile narrowOop*) addr;
242 (void)const_cast<oop&>(v = oopDesc::decode_heap_oop(n));
243 } else {
244 (void)const_cast<oop&>(v = *(volatile oop*) addr);
245 }
246 OrderAccess::acquire();
247 return JNIHandles::make_local(env, v);
248 UNSAFE_END
249
250 UNSAFE_ENTRY(void, Unsafe_SetObjectVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
251 UnsafeWrapper("Unsafe_SetObjectVolatile");
252 oop x = JNIHandles::resolve(x_h);
253 oop p = JNIHandles::resolve(obj);
254 void* addr = index_oop_from_field_offset_long(p, offset);
255 OrderAccess::release();
256 if (UseCompressedOops) {
257 oop_store((narrowOop*)addr, x);
258 } else {
259 oop_store((oop*)addr, x);
260 }
261 OrderAccess::fence();
262 UNSAFE_END
263
264 #ifndef SUPPORTS_NATIVE_CX8
265
266 // VM_Version::supports_cx8() is a surrogate for 'supports atomic long memory ops'.
267 //
268 // On platforms which do not support atomic compare-and-swap of jlong (8 byte)
269 // values we have to use a lock-based scheme to enforce atomicity. This has to be
270 // applied to all Unsafe operations that set the value of a jlong field. Even so
271 // the compareAndSwapLong operation will not be atomic with respect to direct stores
272 // to the field from Java code. It is important therefore that any Java code that
273 // utilizes these Unsafe jlong operations does not perform direct stores. To permit
274 // direct loads of the field from Java code we must also use Atomic::store within the
275 // locked regions. And for good measure, in case there are direct stores, we also
276 // employ Atomic::load within those regions. Note that the field in question must be
277 // volatile and so must have atomic load/store accesses applied at the Java level.
278 //
279 // The locking scheme could utilize a range of strategies for controlling the locking
280 // granularity: from a lock per-field through to a single global lock. The latter is
281 // the simplest and is used for the current implementation. Note that the Java object
282 // that contains the field, can not, in general, be used for locking. To do so can lead
283 // to deadlocks as we may introduce locking into what appears to the Java code to be a
284 // lock-free path.
285 //
286 // As all the locked-regions are very short and themselves non-blocking we can treat
287 // them as leaf routines and elide safepoint checks (ie we don't perform any thread
288 // state transitions even when blocking for the lock). Note that if we do choose to
289 // add safepoint checks and thread state transitions, we must ensure that we calculate
290 // the address of the field _after_ we have acquired the lock, else the object may have
291 // been moved by the GC
292
293 UNSAFE_ENTRY(jlong, Unsafe_GetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset))
294 UnsafeWrapper("Unsafe_GetLongVolatile");
295 {
296 if (VM_Version::supports_cx8()) {
297 GET_FIELD_VOLATILE(obj, offset, jlong, v);
298 return v;
299 }
300 else {
301 Handle p (THREAD, JNIHandles::resolve(obj));
302 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
303 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
304 jlong value = Atomic::load(addr);
305 return value;
306 }
307 }
308 UNSAFE_END
309
310 UNSAFE_ENTRY(void, Unsafe_SetLongVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
311 UnsafeWrapper("Unsafe_SetLongVolatile");
312 {
313 if (VM_Version::supports_cx8()) {
314 SET_FIELD_VOLATILE(obj, offset, jlong, x);
315 }
316 else {
317 Handle p (THREAD, JNIHandles::resolve(obj));
318 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
319 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
320 Atomic::store(x, addr);
321 }
322 }
323 UNSAFE_END
324
325 #endif // not SUPPORTS_NATIVE_CX8
326
327 #define DEFINE_GETSETOOP(jboolean, Boolean) \
328 \
329 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset)) \
330 UnsafeWrapper("Unsafe_Get"#Boolean); \
331 if (obj == NULL) THROW_0(vmSymbols::java_lang_NullPointerException()); \
332 GET_FIELD(obj, offset, jboolean, v); \
333 return v; \
334 UNSAFE_END \
335 \
336 UNSAFE_ENTRY(void, Unsafe_Set##Boolean##140(JNIEnv *env, jobject unsafe, jobject obj, jint offset, jboolean x)) \
337 UnsafeWrapper("Unsafe_Set"#Boolean); \
338 if (obj == NULL) THROW(vmSymbols::java_lang_NullPointerException()); \
339 SET_FIELD(obj, offset, jboolean, x); \
340 UNSAFE_END \
341 \
342 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \
343 UnsafeWrapper("Unsafe_Get"#Boolean); \
344 GET_FIELD(obj, offset, jboolean, v); \
345 return v; \
346 UNSAFE_END \
347 \
348 UNSAFE_ENTRY(void, Unsafe_Set##Boolean(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \
349 UnsafeWrapper("Unsafe_Set"#Boolean); \
350 SET_FIELD(obj, offset, jboolean, x); \
351 UNSAFE_END \
352 \
353 // END DEFINE_GETSETOOP.
354
355 DEFINE_GETSETOOP(jboolean, Boolean)
356 DEFINE_GETSETOOP(jbyte, Byte)
357 DEFINE_GETSETOOP(jshort, Short);
358 DEFINE_GETSETOOP(jchar, Char);
359 DEFINE_GETSETOOP(jint, Int);
360 DEFINE_GETSETOOP(jlong, Long);
361 DEFINE_GETSETOOP(jfloat, Float);
362 DEFINE_GETSETOOP(jdouble, Double);
363
364 #undef DEFINE_GETSETOOP
365
366 #define DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) \
367 \
368 UNSAFE_ENTRY(jboolean, Unsafe_Get##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) \
369 UnsafeWrapper("Unsafe_Get"#Boolean); \
370 GET_FIELD_VOLATILE(obj, offset, jboolean, v); \
371 return v; \
372 UNSAFE_END \
373 \
374 UNSAFE_ENTRY(void, Unsafe_Set##Boolean##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jboolean x)) \
375 UnsafeWrapper("Unsafe_Set"#Boolean); \
376 SET_FIELD_VOLATILE(obj, offset, jboolean, x); \
377 UNSAFE_END \
378 \
379 // END DEFINE_GETSETOOP_VOLATILE.
380
381 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean)
382 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte)
383 DEFINE_GETSETOOP_VOLATILE(jshort, Short);
384 DEFINE_GETSETOOP_VOLATILE(jchar, Char);
385 DEFINE_GETSETOOP_VOLATILE(jint, Int);
386 DEFINE_GETSETOOP_VOLATILE(jfloat, Float);
387 DEFINE_GETSETOOP_VOLATILE(jdouble, Double);
388
389 #ifdef SUPPORTS_NATIVE_CX8
390 DEFINE_GETSETOOP_VOLATILE(jlong, Long);
391 #endif
392
393 #undef DEFINE_GETSETOOP_VOLATILE
394
395 // The non-intrinsified versions of setOrdered just use setVolatile
396
397 UNSAFE_ENTRY(void, Unsafe_SetOrderedInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint x))
398 UnsafeWrapper("Unsafe_SetOrderedInt");
399 SET_FIELD_VOLATILE(obj, offset, jint, x);
400 UNSAFE_END
401
402 UNSAFE_ENTRY(void, Unsafe_SetOrderedObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h))
403 UnsafeWrapper("Unsafe_SetOrderedObject");
404 oop x = JNIHandles::resolve(x_h);
405 oop p = JNIHandles::resolve(obj);
406 void* addr = index_oop_from_field_offset_long(p, offset);
407 OrderAccess::release();
408 if (UseCompressedOops) {
409 oop_store((narrowOop*)addr, x);
410 } else {
411 oop_store((oop*)addr, x);
412 }
413 OrderAccess::fence();
414 UNSAFE_END
415
416 UNSAFE_ENTRY(void, Unsafe_SetOrderedLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong x))
417 UnsafeWrapper("Unsafe_SetOrderedLong");
418 #ifdef SUPPORTS_NATIVE_CX8
419 SET_FIELD_VOLATILE(obj, offset, jlong, x);
420 #else
421 // Keep old code for platforms which may not have atomic long (8 bytes) instructions
422 {
423 if (VM_Version::supports_cx8()) {
424 SET_FIELD_VOLATILE(obj, offset, jlong, x);
425 }
426 else {
427 Handle p (THREAD, JNIHandles::resolve(obj));
428 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
429 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
430 Atomic::store(x, addr);
431 }
432 }
433 #endif
434 UNSAFE_END
435
436 UNSAFE_ENTRY(void, Unsafe_LoadFence(JNIEnv *env, jobject unsafe))
437 UnsafeWrapper("Unsafe_LoadFence");
438 OrderAccess::acquire();
439 UNSAFE_END
440
441 UNSAFE_ENTRY(void, Unsafe_StoreFence(JNIEnv *env, jobject unsafe))
442 UnsafeWrapper("Unsafe_StoreFence");
443 OrderAccess::release();
444 UNSAFE_END
445
446 UNSAFE_ENTRY(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe))
447 UnsafeWrapper("Unsafe_FullFence");
448 OrderAccess::fence();
449 UNSAFE_END
450
451 ////// Data in the C heap.
452
453 // Note: These do not throw NullPointerException for bad pointers.
454 // They just crash. Only a oop base pointer can generate a NullPointerException.
455 //
456 #define DEFINE_GETSETNATIVE(java_type, Type, native_type) \
457 \
458 UNSAFE_ENTRY(java_type, Unsafe_GetNative##Type(JNIEnv *env, jobject unsafe, jlong addr)) \
459 UnsafeWrapper("Unsafe_GetNative"#Type); \
460 void* p = addr_from_java(addr); \
461 JavaThread* t = JavaThread::current(); \
462 t->set_doing_unsafe_access(true); \
463 java_type x = *(volatile native_type*)p; \
464 t->set_doing_unsafe_access(false); \
465 return x; \
466 UNSAFE_END \
467 \
468 UNSAFE_ENTRY(void, Unsafe_SetNative##Type(JNIEnv *env, jobject unsafe, jlong addr, java_type x)) \
469 UnsafeWrapper("Unsafe_SetNative"#Type); \
470 JavaThread* t = JavaThread::current(); \
471 t->set_doing_unsafe_access(true); \
472 void* p = addr_from_java(addr); \
473 *(volatile native_type*)p = x; \
474 t->set_doing_unsafe_access(false); \
475 UNSAFE_END \
476 \
477 // END DEFINE_GETSETNATIVE.
478
479 DEFINE_GETSETNATIVE(jbyte, Byte, signed char)
480 DEFINE_GETSETNATIVE(jshort, Short, signed short);
481 DEFINE_GETSETNATIVE(jchar, Char, unsigned short);
482 DEFINE_GETSETNATIVE(jint, Int, jint);
483 // no long -- handled specially
484 DEFINE_GETSETNATIVE(jfloat, Float, float);
485 DEFINE_GETSETNATIVE(jdouble, Double, double);
486
487 #undef DEFINE_GETSETNATIVE
488
489 UNSAFE_ENTRY(jlong, Unsafe_GetNativeLong(JNIEnv *env, jobject unsafe, jlong addr))
490 UnsafeWrapper("Unsafe_GetNativeLong");
491 JavaThread* t = JavaThread::current();
492 // We do it this way to avoid problems with access to heap using 64
493 // bit loads, as jlong in heap could be not 64-bit aligned, and on
494 // some CPUs (SPARC) it leads to SIGBUS.
495 t->set_doing_unsafe_access(true);
496 void* p = addr_from_java(addr);
497 jlong x;
498 if (((intptr_t)p & 7) == 0) {
499 // jlong is aligned, do a volatile access
500 x = *(volatile jlong*)p;
501 } else {
502 jlong_accessor acc;
503 acc.words[0] = ((volatile jint*)p)[0];
504 acc.words[1] = ((volatile jint*)p)[1];
505 x = acc.long_value;
506 }
507 t->set_doing_unsafe_access(false);
508 return x;
509 UNSAFE_END
510
511 UNSAFE_ENTRY(void, Unsafe_SetNativeLong(JNIEnv *env, jobject unsafe, jlong addr, jlong x))
512 UnsafeWrapper("Unsafe_SetNativeLong");
513 JavaThread* t = JavaThread::current();
514 // see comment for Unsafe_GetNativeLong
515 t->set_doing_unsafe_access(true);
516 void* p = addr_from_java(addr);
517 if (((intptr_t)p & 7) == 0) {
518 // jlong is aligned, do a volatile access
519 *(volatile jlong*)p = x;
520 } else {
521 jlong_accessor acc;
522 acc.long_value = x;
523 ((volatile jint*)p)[0] = acc.words[0];
524 ((volatile jint*)p)[1] = acc.words[1];
525 }
526 t->set_doing_unsafe_access(false);
527 UNSAFE_END
528
529
530 UNSAFE_ENTRY(jlong, Unsafe_GetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr))
531 UnsafeWrapper("Unsafe_GetNativeAddress");
532 void* p = addr_from_java(addr);
533 return addr_to_java(*(void**)p);
534 UNSAFE_END
535
536 UNSAFE_ENTRY(void, Unsafe_SetNativeAddress(JNIEnv *env, jobject unsafe, jlong addr, jlong x))
537 UnsafeWrapper("Unsafe_SetNativeAddress");
538 void* p = addr_from_java(addr);
539 *(void**)p = addr_from_java(x);
540 UNSAFE_END
541
542
543 ////// Allocation requests
544
545 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls))
546 UnsafeWrapper("Unsafe_AllocateInstance");
547 {
548 ThreadToNativeFromVM ttnfv(thread);
549 return env->AllocObject(cls);
550 }
551 UNSAFE_END
552
553 UNSAFE_ENTRY(jlong, Unsafe_AllocateMemory(JNIEnv *env, jobject unsafe, jlong size))
554 UnsafeWrapper("Unsafe_AllocateMemory");
555 size_t sz = (size_t)size;
556 if (sz != (julong)size || size < 0) {
557 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
558 }
559 if (sz == 0) {
560 return 0;
561 }
562 sz = round_to(sz, HeapWordSize);
563 void* x = os::malloc(sz, mtInternal);
564 if (x == NULL) {
565 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
566 }
567 //Copy::fill_to_words((HeapWord*)x, sz / HeapWordSize);
568 return addr_to_java(x);
569 UNSAFE_END
570
571 UNSAFE_ENTRY(jlong, Unsafe_ReallocateMemory(JNIEnv *env, jobject unsafe, jlong addr, jlong size))
572 UnsafeWrapper("Unsafe_ReallocateMemory");
573 void* p = addr_from_java(addr);
574 size_t sz = (size_t)size;
575 if (sz != (julong)size || size < 0) {
576 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
577 }
578 if (sz == 0) {
579 os::free(p);
580 return 0;
581 }
582 sz = round_to(sz, HeapWordSize);
583 void* x = (p == NULL) ? os::malloc(sz, mtInternal) : os::realloc(p, sz, mtInternal);
584 if (x == NULL) {
585 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
586 }
587 return addr_to_java(x);
588 UNSAFE_END
589
590 UNSAFE_ENTRY(void, Unsafe_FreeMemory(JNIEnv *env, jobject unsafe, jlong addr))
591 UnsafeWrapper("Unsafe_FreeMemory");
592 void* p = addr_from_java(addr);
593 if (p == NULL) {
594 return;
595 }
596 os::free(p);
597 UNSAFE_END
598
599 UNSAFE_ENTRY(void, Unsafe_SetMemory(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value))
600 UnsafeWrapper("Unsafe_SetMemory");
601 size_t sz = (size_t)size;
602 if (sz != (julong)size || size < 0) {
603 THROW(vmSymbols::java_lang_IllegalArgumentException());
604 }
605 oop base = JNIHandles::resolve(obj);
606 void* p = index_oop_from_field_offset_long(base, offset);
607 Copy::fill_to_memory_atomic(p, sz, value);
608 UNSAFE_END
609
610 UNSAFE_ENTRY(void, Unsafe_CopyMemory(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size))
611 UnsafeWrapper("Unsafe_CopyMemory");
612 if (size == 0) {
613 return;
614 }
615 size_t sz = (size_t)size;
616 if (sz != (julong)size || size < 0) {
617 THROW(vmSymbols::java_lang_IllegalArgumentException());
618 }
619 oop srcp = JNIHandles::resolve(srcObj);
620 oop dstp = JNIHandles::resolve(dstObj);
621 if (dstp != NULL && !dstp->is_typeArray()) {
622 // NYI: This works only for non-oop arrays at present.
623 // Generalizing it would be reasonable, but requires card marking.
624 // Also, autoboxing a Long from 0L in copyMemory(x,y, 0L,z, n) would be bad.
625 THROW(vmSymbols::java_lang_IllegalArgumentException());
626 }
627 void* src = index_oop_from_field_offset_long(srcp, srcOffset);
628 void* dst = index_oop_from_field_offset_long(dstp, dstOffset);
629 Copy::conjoint_memory_atomic(src, dst, sz);
630 UNSAFE_END
631
632
633 ////// Random queries
634
635 // See comment at file start about UNSAFE_LEAF
636 //UNSAFE_LEAF(jint, Unsafe_AddressSize())
637 UNSAFE_ENTRY(jint, Unsafe_AddressSize(JNIEnv *env, jobject unsafe))
638 UnsafeWrapper("Unsafe_AddressSize");
639 return sizeof(void*);
640 UNSAFE_END
641
642 // See comment at file start about UNSAFE_LEAF
643 //UNSAFE_LEAF(jint, Unsafe_PageSize())
644 UNSAFE_ENTRY(jint, Unsafe_PageSize(JNIEnv *env, jobject unsafe))
645 UnsafeWrapper("Unsafe_PageSize");
646 return os::vm_page_size();
647 UNSAFE_END
648
649 jint find_field_offset(jobject field, int must_be_static, TRAPS) {
650 if (field == NULL) {
651 THROW_0(vmSymbols::java_lang_NullPointerException());
652 }
653
654 oop reflected = JNIHandles::resolve_non_null(field);
655 oop mirror = java_lang_reflect_Field::clazz(reflected);
656 Klass* k = java_lang_Class::as_Klass(mirror);
657 int slot = java_lang_reflect_Field::slot(reflected);
658 int modifiers = java_lang_reflect_Field::modifiers(reflected);
659
660 if (must_be_static >= 0) {
661 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0);
662 if (must_be_static != really_is_static) {
663 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
664 }
665 }
666
667 int offset = InstanceKlass::cast(k)->field_offset(slot);
668 return field_offset_from_byte_offset(offset);
669 }
670
671 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset(JNIEnv *env, jobject unsafe, jobject field))
672 UnsafeWrapper("Unsafe_ObjectFieldOffset");
673 return find_field_offset(field, 0, THREAD);
674 UNSAFE_END
675
676 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset(JNIEnv *env, jobject unsafe, jobject field))
677 UnsafeWrapper("Unsafe_StaticFieldOffset");
678 return find_field_offset(field, 1, THREAD);
679 UNSAFE_END
680
681 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBaseFromField(JNIEnv *env, jobject unsafe, jobject field))
682 UnsafeWrapper("Unsafe_StaticFieldBase");
683 // Note: In this VM implementation, a field address is always a short
684 // offset from the base of a a klass metaobject. Thus, the full dynamic
685 // range of the return type is never used. However, some implementations
686 // might put the static field inside an array shared by many classes,
687 // or even at a fixed address, in which case the address could be quite
688 // large. In that last case, this function would return NULL, since
689 // the address would operate alone, without any base pointer.
690
691 if (field == NULL) THROW_0(vmSymbols::java_lang_NullPointerException());
692
693 oop reflected = JNIHandles::resolve_non_null(field);
694 oop mirror = java_lang_reflect_Field::clazz(reflected);
695 int modifiers = java_lang_reflect_Field::modifiers(reflected);
696
697 if ((modifiers & JVM_ACC_STATIC) == 0) {
698 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
699 }
700
701 return JNIHandles::make_local(env, mirror);
702 UNSAFE_END
703
704 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) {
705 UnsafeWrapper("Unsafe_EnsureClassInitialized");
706 if (clazz == NULL) {
707 THROW(vmSymbols::java_lang_NullPointerException());
708 }
709 oop mirror = JNIHandles::resolve_non_null(clazz);
710
711 Klass* klass = java_lang_Class::as_Klass(mirror);
712 if (klass != NULL && klass->should_be_initialized()) {
713 InstanceKlass* k = InstanceKlass::cast(klass);
714 k->initialize(CHECK);
715 }
716 }
717 UNSAFE_END
718
719 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized(JNIEnv *env, jobject unsafe, jobject clazz)) {
720 UnsafeWrapper("Unsafe_ShouldBeInitialized");
721 if (clazz == NULL) {
722 THROW_(vmSymbols::java_lang_NullPointerException(), false);
723 }
724 oop mirror = JNIHandles::resolve_non_null(clazz);
725 Klass* klass = java_lang_Class::as_Klass(mirror);
726 if (klass != NULL && klass->should_be_initialized()) {
727 return true;
728 }
729 return false;
730 }
731 UNSAFE_END
732
733 static void getBaseAndScale(int& base, int& scale, jclass acls, TRAPS) {
734 if (acls == NULL) {
735 THROW(vmSymbols::java_lang_NullPointerException());
736 }
737 oop mirror = JNIHandles::resolve_non_null(acls);
738 Klass* k = java_lang_Class::as_Klass(mirror);
739 if (k == NULL || !k->oop_is_array()) {
740 THROW(vmSymbols::java_lang_InvalidClassException());
741 } else if (k->oop_is_objArray()) {
742 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT);
743 scale = heapOopSize;
744 } else if (k->oop_is_typeArray()) {
745 TypeArrayKlass* tak = TypeArrayKlass::cast(k);
746 base = tak->array_header_in_bytes();
747 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok");
748 scale = (1 << tak->log2_element_size());
749 } else {
750 ShouldNotReachHere();
751 }
752 }
753
754 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset(JNIEnv *env, jobject unsafe, jclass acls))
755 UnsafeWrapper("Unsafe_ArrayBaseOffset");
756 int base, scale;
757 getBaseAndScale(base, scale, acls, CHECK_0);
758 return field_offset_from_byte_offset(base);
759 UNSAFE_END
760
761
762 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale(JNIEnv *env, jobject unsafe, jclass acls))
763 UnsafeWrapper("Unsafe_ArrayIndexScale");
764 int base, scale;
765 getBaseAndScale(base, scale, acls, CHECK_0);
766 // This VM packs both fields and array elements down to the byte.
767 // But watch out: If this changes, so that array references for
768 // a given primitive type (say, T_BOOLEAN) use different memory units
769 // than fields, this method MUST return zero for such arrays.
770 // For example, the VM used to store sub-word sized fields in full
771 // words in the object layout, so that accessors like getByte(Object,int)
772 // did not really do what one might expect for arrays. Therefore,
773 // this function used to report a zero scale factor, so that the user
774 // would know not to attempt to access sub-word array elements.
775 // // Code for unpacked fields:
776 // if (scale < wordSize) return 0;
777
778 // The following allows for a pretty general fieldOffset cookie scheme,
779 // but requires it to be linear in byte offset.
780 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0);
781 UNSAFE_END
782
783
784 static inline void throw_new(JNIEnv *env, const char *ename) {
785 char buf[100];
786 jio_snprintf(buf, 100, "%s%s", "java/lang/", ename);
787 jclass cls = env->FindClass(buf);
788 if (env->ExceptionCheck()) {
789 env->ExceptionClear();
790 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", buf);
791 return;
792 }
793 char* msg = NULL;
794 env->ThrowNew(cls, msg);
795 }
796
797 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) {
798 {
799 // Code lifted from JDK 1.3 ClassLoader.c
800
801 jbyte *body;
802 char *utfName;
803 jclass result = 0;
804 char buf[128];
805
806 if (UsePerfData) {
807 ClassLoader::unsafe_defineClassCallCounter()->inc();
808 }
809
810 if (data == NULL) {
811 throw_new(env, "NullPointerException");
812 return 0;
813 }
814
815 /* Work around 4153825. malloc crashes on Solaris when passed a
816 * negative size.
817 */
818 if (length < 0) {
819 throw_new(env, "ArrayIndexOutOfBoundsException");
820 return 0;
821 }
822
823 body = NEW_C_HEAP_ARRAY(jbyte, length, mtInternal);
824
825 if (body == 0) {
826 throw_new(env, "OutOfMemoryError");
827 return 0;
828 }
829
830 env->GetByteArrayRegion(data, offset, length, body);
831
832 if (env->ExceptionOccurred())
833 goto free_body;
834
835 if (name != NULL) {
836 uint len = env->GetStringUTFLength(name);
837 int unicode_len = env->GetStringLength(name);
838 if (len >= sizeof(buf)) {
839 utfName = NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
840 if (utfName == NULL) {
841 throw_new(env, "OutOfMemoryError");
842 goto free_body;
843 }
844 } else {
845 utfName = buf;
846 }
847 env->GetStringUTFRegion(name, 0, unicode_len, utfName);
848 //VerifyFixClassname(utfName);
849 for (uint i = 0; i < len; i++) {
850 if (utfName[i] == '.') utfName[i] = '/';
851 }
852 } else {
853 utfName = NULL;
854 }
855
856 result = JVM_DefineClass(env, utfName, loader, body, length, pd);
857
858 if (utfName && utfName != buf)
859 FREE_C_HEAP_ARRAY(char, utfName);
860
861 free_body:
862 FREE_C_HEAP_ARRAY(jbyte, body);
863 return result;
864 }
865 }
866
867
868 UNSAFE_ENTRY(jclass, Unsafe_DefineClass(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd))
869 UnsafeWrapper("Unsafe_DefineClass");
870 {
871 ThreadToNativeFromVM ttnfv(thread);
872 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd);
873 }
874 UNSAFE_END
875
876
877 // define a class but do not make it known to the class loader or system dictionary
878 // - host_class: supplies context for linkage, access control, protection domain, and class loader
879 // - data: bytes of a class file, a raw memory address (length gives the number of bytes)
880 // - cp_patches: where non-null entries exist, they replace corresponding CP entries in data
881
882 // When you load an anonymous class U, it works as if you changed its name just before loading,
883 // to a name that you will never use again. Since the name is lost, no other class can directly
884 // link to any member of U. Just after U is loaded, the only way to use it is reflectively,
885 // through java.lang.Class methods like Class.newInstance.
886
887 // Access checks for linkage sites within U continue to follow the same rules as for named classes.
888 // The package of an anonymous class is given by the package qualifier on the name under which it was loaded.
889 // An anonymous class also has special privileges to access any member of its host class.
890 // This is the main reason why this loading operation is unsafe. The purpose of this is to
891 // allow language implementations to simulate "open classes"; a host class in effect gets
892 // new code when an anonymous class is loaded alongside it. A less convenient but more
893 // standard way to do this is with reflection, which can also be set to ignore access
894 // restrictions.
895
896 // Access into an anonymous class is possible only through reflection. Therefore, there
897 // are no special access rules for calling into an anonymous class. The relaxed access
898 // rule for the host class is applied in the opposite direction: A host class reflectively
899 // access one of its anonymous classes.
900
901 // If you load the same bytecodes twice, you get two different classes. You can reload
902 // the same bytecodes with or without varying CP patches.
903
904 // By using the CP patching array, you can have a new anonymous class U2 refer to an older one U1.
905 // The bytecodes for U2 should refer to U1 by a symbolic name (doesn't matter what the name is).
906 // The CONSTANT_Class entry for that name can be patched to refer directly to U1.
907
908 // This allows, for example, U2 to use U1 as a superclass or super-interface, or as
909 // an outer class (so that U2 is an anonymous inner class of anonymous U1).
910 // It is not possible for a named class, or an older anonymous class, to refer by
911 // name (via its CP) to a newer anonymous class.
912
913 // CP patching may also be used to modify (i.e., hack) the names of methods, classes,
914 // or type descriptors used in the loaded anonymous class.
915
916 // Finally, CP patching may be used to introduce "live" objects into the constant pool,
917 // instead of "dead" strings. A compiled statement like println((Object)"hello") can
918 // be changed to println(greeting), where greeting is an arbitrary object created before
919 // the anonymous class is loaded. This is useful in dynamic languages, in which
920 // various kinds of metaobjects must be introduced as constants into bytecode.
921 // Note the cast (Object), which tells the verifier to expect an arbitrary object,
922 // not just a literal string. For such ldc instructions, the verifier uses the
923 // type Object instead of String, if the loaded constant is not in fact a String.
924
925 static instanceKlassHandle
926 Unsafe_DefineAnonymousClass_impl(JNIEnv *env,
927 jclass host_class, jbyteArray data, jobjectArray cp_patches_jh,
928 HeapWord* *temp_alloc,
929 TRAPS) {
930
931 if (UsePerfData) {
932 ClassLoader::unsafe_defineClassCallCounter()->inc();
933 }
934
935 if (data == NULL) {
936 THROW_0(vmSymbols::java_lang_NullPointerException());
937 }
938
939 jint length = typeArrayOop(JNIHandles::resolve_non_null(data))->length();
940 jint word_length = (length + sizeof(HeapWord)-1) / sizeof(HeapWord);
941 HeapWord* body = NEW_C_HEAP_ARRAY(HeapWord, word_length, mtInternal);
942 if (body == NULL) {
943 THROW_0(vmSymbols::java_lang_OutOfMemoryError());
944 }
945
946 // caller responsible to free it:
947 (*temp_alloc) = body;
948
949 {
950 jbyte* array_base = typeArrayOop(JNIHandles::resolve_non_null(data))->byte_at_addr(0);
951 Copy::conjoint_words((HeapWord*) array_base, body, word_length);
952 }
953
954 u1* class_bytes = (u1*) body;
955 int class_bytes_length = (int) length;
956 if (class_bytes_length < 0) class_bytes_length = 0;
957 if (class_bytes == NULL
958 || host_class == NULL
959 || length != class_bytes_length)
960 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
961
962 objArrayHandle cp_patches_h;
963 if (cp_patches_jh != NULL) {
964 oop p = JNIHandles::resolve_non_null(cp_patches_jh);
965 if (!p->is_objArray())
966 THROW_0(vmSymbols::java_lang_IllegalArgumentException());
967 cp_patches_h = objArrayHandle(THREAD, (objArrayOop)p);
968 }
969
970 KlassHandle host_klass(THREAD, java_lang_Class::as_Klass(JNIHandles::resolve_non_null(host_class)));
971 const char* host_source = host_klass->external_name();
972 Handle host_loader(THREAD, host_klass->class_loader());
973 Handle host_domain(THREAD, host_klass->protection_domain());
974
975 GrowableArray<Handle>* cp_patches = NULL;
976 if (cp_patches_h.not_null()) {
977 int alen = cp_patches_h->length();
978 for (int i = alen-1; i >= 0; i--) {
979 oop p = cp_patches_h->obj_at(i);
980 if (p != NULL) {
981 Handle patch(THREAD, p);
982 if (cp_patches == NULL)
983 cp_patches = new GrowableArray<Handle>(i+1, i+1, Handle());
984 cp_patches->at_put(i, patch);
985 }
986 }
987 }
988
989 ClassFileStream st(class_bytes, class_bytes_length, (char*) host_source);
990
991 instanceKlassHandle anon_klass;
992 {
993 Symbol* no_class_name = NULL;
994 Klass* anonk = SystemDictionary::parse_stream(no_class_name,
995 host_loader, host_domain,
996 &st, host_klass, cp_patches,
997 CHECK_NULL);
998 if (anonk == NULL) return NULL;
999 anon_klass = instanceKlassHandle(THREAD, anonk);
1000 }
1001
1002 return anon_klass;
1003 }
1004
1005 UNSAFE_ENTRY(jclass, Unsafe_DefineAnonymousClass(JNIEnv *env, jobject unsafe, jclass host_class, jbyteArray data, jobjectArray cp_patches_jh))
1006 {
1007 instanceKlassHandle anon_klass;
1008 jobject res_jh = NULL;
1009
1010 UnsafeWrapper("Unsafe_DefineAnonymousClass");
1011 ResourceMark rm(THREAD);
1012
1013 HeapWord* temp_alloc = NULL;
1014
1015 anon_klass = Unsafe_DefineAnonymousClass_impl(env, host_class, data,
1016 cp_patches_jh,
1017 &temp_alloc, THREAD);
1018 if (anon_klass() != NULL)
1019 res_jh = JNIHandles::make_local(env, anon_klass->java_mirror());
1020
1021 // try/finally clause:
1022 if (temp_alloc != NULL) {
1023 FREE_C_HEAP_ARRAY(HeapWord, temp_alloc);
1024 }
1025
1026 // The anonymous class loader data has been artificially been kept alive to
1027 // this point. The mirror and any instances of this class have to keep
1028 // it alive afterwards.
1029 if (anon_klass() != NULL) {
1030 anon_klass->class_loader_data()->set_keep_alive(false);
1031 }
1032
1033 // let caller initialize it as needed...
1034
1035 return (jclass) res_jh;
1036 }
1037 UNSAFE_END
1038
1039
1040
1041 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr))
1042 UnsafeWrapper("Unsafe_ThrowException");
1043 {
1044 ThreadToNativeFromVM ttnfv(thread);
1045 env->Throw(thr);
1046 }
1047 UNSAFE_END
1048
1049 // JSR166 ------------------------------------------------------------------
1050
1051 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapObject(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h))
1052 UnsafeWrapper("Unsafe_CompareAndSwapObject");
1053 oop x = JNIHandles::resolve(x_h);
1054 oop e = JNIHandles::resolve(e_h);
1055 oop p = JNIHandles::resolve(obj);
1056 HeapWord* addr = (HeapWord *)index_oop_from_field_offset_long(p, offset);
1057 oop res = oopDesc::atomic_compare_exchange_oop(x, addr, e, true);
1058 jboolean success = (res == e);
1059 if (success)
1060 update_barrier_set((void*)addr, x);
1061 return success;
1062 UNSAFE_END
1063
1064 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x))
1065 UnsafeWrapper("Unsafe_CompareAndSwapInt");
1066 oop p = JNIHandles::resolve(obj);
1067 jint* addr = (jint *) index_oop_from_field_offset_long(p, offset);
1068 return (jint)(Atomic::cmpxchg(x, addr, e)) == e;
1069 UNSAFE_END
1070
1071 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSwapLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x))
1072 UnsafeWrapper("Unsafe_CompareAndSwapLong");
1073 Handle p (THREAD, JNIHandles::resolve(obj));
1074 jlong* addr = (jlong*)(index_oop_from_field_offset_long(p(), offset));
1075 #ifdef SUPPORTS_NATIVE_CX8
1076 return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1077 #else
1078 if (VM_Version::supports_cx8())
1079 return (jlong)(Atomic::cmpxchg(x, addr, e)) == e;
1080 else {
1081 jboolean success = false;
1082 MutexLockerEx mu(UnsafeJlong_lock, Mutex::_no_safepoint_check_flag);
1083 jlong val = Atomic::load(addr);
1084 if (val == e) { Atomic::store(x, addr); success = true; }
1085 return success;
1086 }
1087 #endif
1088 UNSAFE_END
1089
1090 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time))
1091 UnsafeWrapper("Unsafe_Park");
1092 EventThreadPark event;
1093 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time);
1094
1095 JavaThreadParkedState jtps(thread, time != 0);
1096 thread->parker()->park(isAbsolute != 0, time);
1097
1098 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker());
1099 if (event.should_commit()) {
1100 oop obj = thread->current_park_blocker();
1101 event.set_klass((obj != NULL) ? obj->klass() : NULL);
1102 event.set_timeout(time);
1103 event.set_address((obj != NULL) ? (TYPE_ADDRESS) cast_from_oop<uintptr_t>(obj) : 0);
1104 event.commit();
1105 }
1106 UNSAFE_END
1107
1108 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread))
1109 UnsafeWrapper("Unsafe_Unpark");
1110 Parker* p = NULL;
1111 if (jthread != NULL) {
1112 oop java_thread = JNIHandles::resolve_non_null(jthread);
1113 if (java_thread != NULL) {
1114 jlong lp = java_lang_Thread::park_event(java_thread);
1115 if (lp != 0) {
1116 // This cast is OK even though the jlong might have been read
1117 // non-atomically on 32bit systems, since there, one word will
1118 // always be zero anyway and the value set is always the same
1119 p = (Parker*)addr_from_java(lp);
1120 } else {
1121 // Grab lock if apparently null or using older version of library
1122 MutexLocker mu(Threads_lock);
1123 java_thread = JNIHandles::resolve_non_null(jthread);
1124 if (java_thread != NULL) {
1125 JavaThread* thr = java_lang_Thread::thread(java_thread);
1126 if (thr != NULL) {
1127 p = thr->parker();
1128 if (p != NULL) { // Bind to Java thread for next time.
1129 java_lang_Thread::set_park_event(java_thread, addr_to_java(p));
1130 }
1131 }
1132 }
1133 }
1134 }
1135 }
1136 if (p != NULL) {
1137 HOTSPOT_THREAD_UNPARK((uintptr_t) p);
1138 p->unpark();
1139 }
1140 UNSAFE_END
1141
1142 UNSAFE_ENTRY(jint, Unsafe_Loadavg(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem))
1143 UnsafeWrapper("Unsafe_Loadavg");
1144 const int max_nelem = 3;
1145 double la[max_nelem];
1146 jint ret;
1147
1148 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg));
1149 assert(a->is_typeArray(), "must be type array");
1150
1151 if (nelem < 0 || nelem > max_nelem || a->length() < nelem) {
1152 ThreadToNativeFromVM ttnfv(thread);
1153 throw_new(env, "ArrayIndexOutOfBoundsException");
1154 return -1;
1155 }
1156
1157 ret = os::loadavg(la, nelem);
1158 if (ret == -1) return -1;
1159
1160 // if successful, ret is the number of samples actually retrieved.
1161 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value");
1162 switch(ret) {
1163 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through
1164 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through
1165 case 1: a->double_at_put(0, (jdouble)la[0]); break;
1166 }
1167 return ret;
1168 UNSAFE_END
1169
1170
1171 /// JVM_RegisterUnsafeMethods
1172
1173 #define ADR "J"
1174
1175 #define LANG "Ljava/lang/"
1176
1177 #define OBJ LANG"Object;"
1178 #define CLS LANG"Class;"
1179 #define FLD LANG"reflect/Field;"
1180 #define THR LANG"Throwable;"
1181
1182 #define DC_Args LANG"String;[BII" LANG"ClassLoader;" "Ljava/security/ProtectionDomain;"
1183 #define DAC_Args CLS"[B["OBJ
1184
1185 #define CC (char*) /*cast a literal from (const char*)*/
1186 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f)
1187
1188 #define DECLARE_GETPUTOOP(Boolean, Z) \
1189 {CC"get"#Boolean, CC"("OBJ"J)"#Z, FN_PTR(Unsafe_Get##Boolean)}, \
1190 {CC"put"#Boolean, CC"("OBJ"J"#Z")V", FN_PTR(Unsafe_Set##Boolean)}, \
1191 {CC"get"#Boolean"Volatile", CC"("OBJ"J)"#Z, FN_PTR(Unsafe_Get##Boolean##Volatile)}, \
1192 {CC"put"#Boolean"Volatile", CC"("OBJ"J"#Z")V", FN_PTR(Unsafe_Set##Boolean##Volatile)}
1193
1194
1195 #define DECLARE_GETPUTNATIVE(Byte, B) \
1196 {CC"get"#Byte, CC"("ADR")"#B, FN_PTR(Unsafe_GetNative##Byte)}, \
1197 {CC"put"#Byte, CC"("ADR#B")V", FN_PTR(Unsafe_SetNative##Byte)}
1198
1199
1200
1201 static JNINativeMethod methods[] = {
1202 {CC"getObject", CC"("OBJ"J)"OBJ"", FN_PTR(Unsafe_GetObject)},
1203 {CC"putObject", CC"("OBJ"J"OBJ")V", FN_PTR(Unsafe_SetObject)},
1204 {CC"getObjectVolatile",CC"("OBJ"J)"OBJ"", FN_PTR(Unsafe_GetObjectVolatile)},
1205 {CC"putObjectVolatile",CC"("OBJ"J"OBJ")V", FN_PTR(Unsafe_SetObjectVolatile)},
1206
1207 DECLARE_GETPUTOOP(Boolean, Z),
1208 DECLARE_GETPUTOOP(Byte, B),
1209 DECLARE_GETPUTOOP(Short, S),
1210 DECLARE_GETPUTOOP(Char, C),
1211 DECLARE_GETPUTOOP(Int, I),
1212 DECLARE_GETPUTOOP(Long, J),
1213 DECLARE_GETPUTOOP(Float, F),
1214 DECLARE_GETPUTOOP(Double, D),
1215
1216 DECLARE_GETPUTNATIVE(Byte, B),
1217 DECLARE_GETPUTNATIVE(Short, S),
1218 DECLARE_GETPUTNATIVE(Char, C),
1219 DECLARE_GETPUTNATIVE(Int, I),
1220 DECLARE_GETPUTNATIVE(Long, J),
1221 DECLARE_GETPUTNATIVE(Float, F),
1222 DECLARE_GETPUTNATIVE(Double, D),
1223
1224 {CC"getAddress", CC"("ADR")"ADR, FN_PTR(Unsafe_GetNativeAddress)},
1225 {CC"putAddress", CC"("ADR""ADR")V", FN_PTR(Unsafe_SetNativeAddress)},
1226
1227 {CC"allocateMemory", CC"(J)"ADR, FN_PTR(Unsafe_AllocateMemory)},
1228 {CC"reallocateMemory", CC"("ADR"J)"ADR, FN_PTR(Unsafe_ReallocateMemory)},
1229 {CC"freeMemory", CC"("ADR")V", FN_PTR(Unsafe_FreeMemory)},
1230
1231 {CC"objectFieldOffset", CC"("FLD")J", FN_PTR(Unsafe_ObjectFieldOffset)},
1232 {CC"staticFieldOffset", CC"("FLD")J", FN_PTR(Unsafe_StaticFieldOffset)},
1233 {CC"staticFieldBase", CC"("FLD")"OBJ, FN_PTR(Unsafe_StaticFieldBaseFromField)},
1234 {CC"ensureClassInitialized",CC"("CLS")V", FN_PTR(Unsafe_EnsureClassInitialized)},
1235 {CC"arrayBaseOffset", CC"("CLS")I", FN_PTR(Unsafe_ArrayBaseOffset)},
1236 {CC"arrayIndexScale", CC"("CLS")I", FN_PTR(Unsafe_ArrayIndexScale)},
1237 {CC"addressSize", CC"()I", FN_PTR(Unsafe_AddressSize)},
1238 {CC"pageSize", CC"()I", FN_PTR(Unsafe_PageSize)},
1239
1240 {CC"defineClass", CC"("DC_Args")"CLS, FN_PTR(Unsafe_DefineClass)},
1241 {CC"allocateInstance", CC"("CLS")"OBJ, FN_PTR(Unsafe_AllocateInstance)},
1242 {CC"throwException", CC"("THR")V", FN_PTR(Unsafe_ThrowException)},
1243 {CC"compareAndSwapObject", CC"("OBJ"J"OBJ""OBJ")Z", FN_PTR(Unsafe_CompareAndSwapObject)},
1244 {CC"compareAndSwapInt", CC"("OBJ"J""I""I"")Z", FN_PTR(Unsafe_CompareAndSwapInt)},
1245 {CC"compareAndSwapLong", CC"("OBJ"J""J""J"")Z", FN_PTR(Unsafe_CompareAndSwapLong)},
1246 {CC"putOrderedObject", CC"("OBJ"J"OBJ")V", FN_PTR(Unsafe_SetOrderedObject)},
1247 {CC"putOrderedInt", CC"("OBJ"JI)V", FN_PTR(Unsafe_SetOrderedInt)},
1248 {CC"putOrderedLong", CC"("OBJ"JJ)V", FN_PTR(Unsafe_SetOrderedLong)},
1249 {CC"park", CC"(ZJ)V", FN_PTR(Unsafe_Park)},
1250 {CC"unpark", CC"("OBJ")V", FN_PTR(Unsafe_Unpark)},
1251
1252 {CC"getLoadAverage", CC"([DI)I", FN_PTR(Unsafe_Loadavg)},
1253
1254 {CC"copyMemory", CC"("OBJ"J"OBJ"JJ)V", FN_PTR(Unsafe_CopyMemory)},
1255 {CC"setMemory", CC"("OBJ"JJB)V", FN_PTR(Unsafe_SetMemory)},
1256
1257 {CC"defineAnonymousClass", CC"("DAC_Args")"CLS, FN_PTR(Unsafe_DefineAnonymousClass)},
1258
1259 {CC"shouldBeInitialized",CC"("CLS")Z", FN_PTR(Unsafe_ShouldBeInitialized)},
1260
1261 {CC"loadFence", CC"()V", FN_PTR(Unsafe_LoadFence)},
1262 {CC"storeFence", CC"()V", FN_PTR(Unsafe_StoreFence)},
1263 {CC"fullFence", CC"()V", FN_PTR(Unsafe_FullFence)},
1264 };
1265
1266 #undef CC
1267 #undef FN_PTR
1268
1269 #undef ADR
1270 #undef LANG
1271 #undef OBJ
1272 #undef CLS
1273 #undef FLD
1274 #undef THR
1275 #undef DC_Args
1276 #undef DAC_Args
1277
1278 #undef DECLARE_GETPUTOOP
1279 #undef DECLARE_GETPUTNATIVE
1280
1281
1282 // This one function is exported, used by NativeLookup.
1283 // The Unsafe_xxx functions above are called only from the interpreter.
1284 // The optimizer looks at names and signatures to recognize
1285 // individual functions.
1286
1287 JVM_ENTRY(void, JVM_RegisterUnsafeMethods(JNIEnv *env, jclass unsafeclass))
1288 UnsafeWrapper("JVM_RegisterUnsafeMethods");
1289 {
1290 ThreadToNativeFromVM ttnfv(thread);
1291
1292 int ok = env->RegisterNatives(unsafeclass, methods, sizeof(methods)/sizeof(JNINativeMethod));
1293 guarantee(ok == 0, "register unsafe natives");
1294 }
1295 JVM_END