1 /* 2 * Copyright (c) 2000, 2025, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "classfile/classFileStream.hpp" 26 #include "classfile/classLoader.hpp" 27 #include "classfile/classLoadInfo.hpp" 28 #include "classfile/javaClasses.inline.hpp" 29 #include "classfile/systemDictionary.hpp" 30 #include "classfile/vmSymbols.hpp" 31 #include "jfr/jfrEvents.hpp" 32 #include "jni.h" 33 #include "jvm.h" 34 #include "memory/allocation.inline.hpp" 35 #include "memory/resourceArea.hpp" 36 #include "logging/log.hpp" 37 #include "logging/logStream.hpp" 38 #include "oops/access.inline.hpp" 39 #include "oops/fieldStreams.inline.hpp" 40 #include "oops/flatArrayKlass.hpp" 41 #include "oops/flatArrayOop.inline.hpp" 42 #include "oops/inlineKlass.inline.hpp" 43 #include "oops/instanceKlass.inline.hpp" 44 #include "oops/klass.inline.hpp" 45 #include "oops/objArrayOop.inline.hpp" 46 #include "oops/oop.inline.hpp" 47 #include "oops/typeArrayOop.inline.hpp" 48 #include "prims/jvmtiExport.hpp" 49 #include "prims/unsafe.hpp" 50 #include "runtime/fieldDescriptor.inline.hpp" 51 #include "runtime/globals.hpp" 52 #include "runtime/handles.inline.hpp" 53 #include "runtime/interfaceSupport.inline.hpp" 54 #include "runtime/javaThread.inline.hpp" 55 #include "runtime/jniHandles.inline.hpp" 56 #include "runtime/orderAccess.hpp" 57 #include "runtime/reflection.hpp" 58 #include "runtime/sharedRuntime.hpp" 59 #include "runtime/stubRoutines.hpp" 60 #include "runtime/threadSMR.hpp" 61 #include "runtime/vmOperations.hpp" 62 #include "runtime/vm_version.hpp" 63 #include "sanitizers/ub.hpp" 64 #include "services/threadService.hpp" 65 #include "utilities/align.hpp" 66 #include "utilities/copy.hpp" 67 #include "utilities/dtrace.hpp" 68 #include "utilities/macros.hpp" 69 70 /** 71 * Implementation of the jdk.internal.misc.Unsafe class 72 */ 73 74 75 #define MAX_OBJECT_SIZE \ 76 ( arrayOopDesc::base_offset_in_bytes(T_DOUBLE) \ 77 + ((julong)max_jint * sizeof(double)) ) 78 79 #define UNSAFE_ENTRY(result_type, header) \ 80 JVM_ENTRY(static result_type, header) 81 82 #define UNSAFE_LEAF(result_type, header) \ 83 JVM_LEAF(static result_type, header) 84 85 // All memory access methods (e.g. getInt, copyMemory) must use this macro. 86 // We call these methods "scoped" methods, as access to these methods is 87 // typically governed by a "scope" (a MemorySessionImpl object), and no 88 // access is allowed when the scope is no longer alive. 89 // 90 // Closing a scope object (cf. scopedMemoryAccess.cpp) can install 91 // an async exception during a safepoint. When that happens, 92 // scoped methods are not allowed to touch the underlying memory (as that 93 // memory might have been released). Therefore, when entering a scoped method 94 // we check if an async exception has been installed, and return immediately 95 // if that is the case. 96 // 97 // As a rule, we disallow safepoints in the middle of a scoped method. 98 // If an async exception handshake were installed in such a safepoint, 99 // memory access might still occur before the handshake is honored by 100 // the accessing thread. 101 // 102 // Corollary: as threads in native state are considered to be at a safepoint, 103 // scoped methods must NOT be executed while in the native thread state. 104 // Because of this, there can be no UNSAFE_LEAF_SCOPED. 105 #define UNSAFE_ENTRY_SCOPED(result_type, header) \ 106 JVM_ENTRY(static result_type, header) \ 107 if (thread->has_async_exception_condition()) {return (result_type)0;} 108 109 #define UNSAFE_END JVM_END 110 111 112 static inline void* addr_from_java(jlong addr) { 113 // This assert fails in a variety of ways on 32-bit systems. 114 // It is impossible to predict whether native code that converts 115 // pointers to longs will sign-extend or zero-extend the addresses. 116 //assert(addr == (uintptr_t)addr, "must not be odd high bits"); 117 return (void*)(uintptr_t)addr; 118 } 119 120 static inline jlong addr_to_java(void* p) { 121 assert(p == (void*)(uintptr_t)p, "must not be odd high bits"); 122 return (uintptr_t)p; 123 } 124 125 126 // Note: The VM's obj_field and related accessors use byte-scaled 127 // ("unscaled") offsets, just as the unsafe methods do. 128 129 // However, the method Unsafe.fieldOffset explicitly declines to 130 // guarantee this. The field offset values manipulated by the Java user 131 // through the Unsafe API are opaque cookies that just happen to be byte 132 // offsets. We represent this state of affairs by passing the cookies 133 // through conversion functions when going between the VM and the Unsafe API. 134 // The conversion functions just happen to be no-ops at present. 135 136 static inline jlong field_offset_to_byte_offset(jlong field_offset) { 137 return field_offset; 138 } 139 140 static inline int field_offset_from_byte_offset(int byte_offset) { 141 return byte_offset; 142 } 143 144 static inline void assert_field_offset_sane(oop p, jlong field_offset) { 145 #ifdef ASSERT 146 jlong byte_offset = field_offset_to_byte_offset(field_offset); 147 148 if (p != nullptr) { 149 assert(byte_offset >= 0 && byte_offset <= (jlong)MAX_OBJECT_SIZE, "sane offset"); 150 if (byte_offset == (jint)byte_offset) { 151 void* ptr_plus_disp = cast_from_oop<address>(p) + byte_offset; 152 assert(p->field_addr<void>((jint)byte_offset) == ptr_plus_disp, 153 "raw [ptr+disp] must be consistent with oop::field_addr"); 154 } 155 jlong p_size = HeapWordSize * (jlong)(p->size()); 156 assert(byte_offset < p_size, "Unsafe access: offset " INT64_FORMAT " > object's size " INT64_FORMAT, (int64_t)byte_offset, (int64_t)p_size); 157 } 158 #endif 159 } 160 161 static inline void* index_oop_from_field_offset_long(oop p, jlong field_offset) { 162 assert_field_offset_sane(p, field_offset); 163 uintptr_t base_address = cast_from_oop<uintptr_t>(p); 164 uintptr_t byte_offset = (uintptr_t)field_offset_to_byte_offset(field_offset); 165 return (void*)(base_address + byte_offset); 166 } 167 168 // Externally callable versions: 169 // (Use these in compiler intrinsics which emulate unsafe primitives.) 170 jlong Unsafe_field_offset_to_byte_offset(jlong field_offset) { 171 return field_offset; 172 } 173 jlong Unsafe_field_offset_from_byte_offset(jlong byte_offset) { 174 return byte_offset; 175 } 176 177 ///// Data read/writes on the Java heap and in native (off-heap) memory 178 179 /** 180 * Helper class to wrap memory accesses in JavaThread::doing_unsafe_access() 181 */ 182 class GuardUnsafeAccess { 183 JavaThread* _thread; 184 185 public: 186 GuardUnsafeAccess(JavaThread* thread) : _thread(thread) { 187 // native/off-heap access which may raise SIGBUS if accessing 188 // memory mapped file data in a region of the file which has 189 // been truncated and is now invalid. 190 _thread->set_doing_unsafe_access(true); 191 } 192 193 ~GuardUnsafeAccess() { 194 _thread->set_doing_unsafe_access(false); 195 } 196 }; 197 198 /** 199 * Helper class for accessing memory. 200 * 201 * Normalizes values and wraps accesses in 202 * JavaThread::doing_unsafe_access() if needed. 203 */ 204 template <typename T> 205 class MemoryAccess : StackObj { 206 JavaThread* _thread; 207 oop _obj; 208 ptrdiff_t _offset; 209 210 // Resolves and returns the address of the memory access. 211 // This raw memory access may fault, so we make sure it happens within the 212 // guarded scope by making the access volatile at least. Since the store 213 // of Thread::set_doing_unsafe_access() is also volatile, these accesses 214 // can not be reordered by the compiler. Therefore, if the access triggers 215 // a fault, we will know that Thread::doing_unsafe_access() returns true. 216 volatile T* addr() { 217 void* addr = index_oop_from_field_offset_long(_obj, _offset); 218 return static_cast<volatile T*>(addr); 219 } 220 221 template <typename U> 222 U normalize_for_write(U x) { 223 return x; 224 } 225 226 jboolean normalize_for_write(jboolean x) { 227 return x & 1; 228 } 229 230 template <typename U> 231 U normalize_for_read(U x) { 232 return x; 233 } 234 235 jboolean normalize_for_read(jboolean x) { 236 return x != 0; 237 } 238 239 public: 240 MemoryAccess(JavaThread* thread, jobject obj, jlong offset) 241 : _thread(thread), _obj(JNIHandles::resolve(obj)), _offset((ptrdiff_t)offset) { 242 assert_field_offset_sane(_obj, offset); 243 } 244 245 T get() { 246 GuardUnsafeAccess guard(_thread); 247 return normalize_for_read(*addr()); 248 } 249 250 // we use this method at some places for writing to 0 e.g. to cause a crash; 251 // ubsan does not know that this is the desired behavior 252 ATTRIBUTE_NO_UBSAN 253 void put(T x) { 254 GuardUnsafeAccess guard(_thread); 255 assert(_obj == nullptr || !_obj->is_inline_type() || _obj->mark().is_larval_state(), "must be an object instance or a larval inline type"); 256 *addr() = normalize_for_write(x); 257 } 258 259 T get_volatile() { 260 GuardUnsafeAccess guard(_thread); 261 volatile T ret = RawAccess<MO_SEQ_CST>::load(addr()); 262 return normalize_for_read(ret); 263 } 264 265 void put_volatile(T x) { 266 GuardUnsafeAccess guard(_thread); 267 RawAccess<MO_SEQ_CST>::store(addr(), normalize_for_write(x)); 268 } 269 }; 270 271 #ifdef ASSERT 272 /* 273 * Get the field descriptor of the field of the given object at the given offset. 274 */ 275 static bool get_field_descriptor(oop p, jlong offset, fieldDescriptor* fd) { 276 bool found = false; 277 Klass* k = p->klass(); 278 if (k->is_instance_klass()) { 279 InstanceKlass* ik = InstanceKlass::cast(k); 280 found = ik->find_field_from_offset((int)offset, false, fd); 281 if (!found && ik->is_mirror_instance_klass()) { 282 Klass* k2 = java_lang_Class::as_Klass(p); 283 if (k2->is_instance_klass()) { 284 ik = InstanceKlass::cast(k2); 285 found = ik->find_field_from_offset((int)offset, true, fd); 286 } 287 } 288 } 289 return found; 290 } 291 #endif // ASSERT 292 293 static void assert_and_log_unsafe_value_access(oop p, jlong offset, InlineKlass* vk) { 294 Klass* k = p->klass(); 295 #ifdef ASSERT 296 if (k->is_instance_klass()) { 297 assert_field_offset_sane(p, offset); 298 fieldDescriptor fd; 299 bool found = get_field_descriptor(p, offset, &fd); 300 if (found) { 301 assert(found, "value field not found"); 302 assert(fd.is_flat(), "field not flat"); 303 } else { 304 if (log_is_enabled(Trace, valuetypes)) { 305 log_trace(valuetypes)("not a field in %s at offset " UINT64_FORMAT_X, 306 p->klass()->external_name(), (uint64_t)offset); 307 } 308 } 309 } else if (k->is_flatArray_klass()) { 310 FlatArrayKlass* vak = FlatArrayKlass::cast(k); 311 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size(); 312 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper()); 313 assert(dest == (cast_from_oop<address>(p) + offset), "invalid offset"); 314 } else { 315 ShouldNotReachHere(); 316 } 317 #endif // ASSERT 318 if (log_is_enabled(Trace, valuetypes)) { 319 if (k->is_flatArray_klass()) { 320 FlatArrayKlass* vak = FlatArrayKlass::cast(k); 321 int index = (offset - vak->array_header_in_bytes()) / vak->element_byte_size(); 322 address dest = (address)((flatArrayOop)p)->value_at_addr(index, vak->layout_helper()); 323 log_trace(valuetypes)("%s array type %s index %d element size %d offset " UINT64_FORMAT_X " at " INTPTR_FORMAT, 324 p->klass()->external_name(), vak->external_name(), 325 index, vak->element_byte_size(), (uint64_t)offset, p2i(dest)); 326 } else { 327 log_trace(valuetypes)("%s field type %s at offset " UINT64_FORMAT_X, 328 p->klass()->external_name(), vk->external_name(), (uint64_t)offset); 329 } 330 } 331 } 332 333 // These functions allow a null base pointer with an arbitrary address. 334 // But if the base pointer is non-null, the offset should make some sense. 335 // That is, it should be in the range [0, MAX_OBJECT_SIZE]. 336 UNSAFE_ENTRY(jobject, Unsafe_GetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { 337 oop p = JNIHandles::resolve(obj); 338 assert_field_offset_sane(p, offset); 339 oop v = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset); 340 return JNIHandles::make_local(THREAD, v); 341 } UNSAFE_END 342 343 UNSAFE_ENTRY(void, Unsafe_PutReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) { 344 oop x = JNIHandles::resolve(x_h); 345 oop p = JNIHandles::resolve(obj); 346 assert_field_offset_sane(p, offset); 347 assert(!p->is_inline_type() || p->mark().is_larval_state(), "must be an object instance or a larval inline type"); 348 HeapAccess<ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x); 349 } UNSAFE_END 350 351 UNSAFE_ENTRY(jlong, Unsafe_ValueHeaderSize(JNIEnv *env, jobject unsafe, jclass c)) { 352 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c)); 353 InlineKlass* vk = InlineKlass::cast(k); 354 return vk->payload_offset(); 355 } UNSAFE_END 356 357 UNSAFE_ENTRY(jboolean, Unsafe_IsFlatField(JNIEnv *env, jobject unsafe, jobject o)) { 358 oop f = JNIHandles::resolve_non_null(o); 359 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f)); 360 int slot = java_lang_reflect_Field::slot(f); 361 return InstanceKlass::cast(k)->field_is_flat(slot); 362 } UNSAFE_END 363 364 UNSAFE_ENTRY(jboolean, Unsafe_HasNullMarker(JNIEnv *env, jobject unsafe, jobject o)) { 365 oop f = JNIHandles::resolve_non_null(o); 366 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f)); 367 int slot = java_lang_reflect_Field::slot(f); 368 return InstanceKlass::cast(k)->field_has_null_marker(slot); 369 } UNSAFE_END 370 371 UNSAFE_ENTRY(jint, Unsafe_NullMarkerOffset(JNIEnv *env, jobject unsafe, jobject o)) { 372 oop f = JNIHandles::resolve_non_null(o); 373 Klass* k = java_lang_Class::as_Klass(java_lang_reflect_Field::clazz(f)); 374 int slot = java_lang_reflect_Field::slot(f); 375 return InstanceKlass::cast(k)->null_marker_offset(slot); 376 } UNSAFE_END 377 378 UNSAFE_ENTRY(jint, Unsafe_ArrayLayout(JNIEnv *env, jobject unsafe, jclass c)) { 379 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c)); 380 if (!k->is_flatArray_klass()) { 381 return LayoutKind::REFERENCE; 382 } else { 383 return (jint)FlatArrayKlass::cast(k)->layout_kind(); 384 } 385 } UNSAFE_END 386 387 UNSAFE_ENTRY(jint, Unsafe_FieldLayout(JNIEnv *env, jobject unsafe, jobject field)) { 388 assert(field != nullptr, "field must not be null"); 389 390 oop reflected = JNIHandles::resolve_non_null(field); 391 oop mirror = java_lang_reflect_Field::clazz(reflected); 392 Klass* k = java_lang_Class::as_Klass(mirror); 393 int slot = java_lang_reflect_Field::slot(reflected); 394 int modifiers = java_lang_reflect_Field::modifiers(reflected); 395 396 if ((modifiers & JVM_ACC_STATIC) != 0) { 397 return (jint)LayoutKind::REFERENCE; // static fields are never flat 398 } else { 399 InstanceKlass* ik = InstanceKlass::cast(k); 400 if (ik->field_is_flat(slot)) { 401 return (jint)ik->inline_layout_info(slot).kind(); 402 } else { 403 return (jint)LayoutKind::REFERENCE; 404 } 405 } 406 } UNSAFE_END 407 408 UNSAFE_ENTRY(jboolean, Unsafe_IsFlatArray(JNIEnv *env, jobject unsafe, jclass c)) { 409 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(c)); 410 return k->is_flatArray_klass(); 411 } UNSAFE_END 412 413 UNSAFE_ENTRY(jobject, Unsafe_GetValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc)) { 414 oop base = JNIHandles::resolve(obj); 415 if (base == nullptr) { 416 THROW_NULL(vmSymbols::java_lang_NullPointerException()); 417 } 418 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)); 419 InlineKlass* vk = InlineKlass::cast(k); 420 assert_and_log_unsafe_value_access(base, offset, vk); 421 LayoutKind lk = LayoutKind::UNKNOWN; 422 if (base->is_array()) { 423 FlatArrayKlass* fak = FlatArrayKlass::cast(base->klass()); 424 lk = fak->layout_kind(); 425 } else { 426 fieldDescriptor fd; 427 InstanceKlass::cast(base->klass())->find_field_from_offset(offset, false, &fd); 428 lk = fd.field_holder()->inline_layout_info(fd.index()).kind(); 429 } 430 Handle base_h(THREAD, base); 431 oop v = vk->read_payload_from_addr(base_h(), offset, lk, CHECK_NULL); 432 return JNIHandles::make_local(THREAD, v); 433 } UNSAFE_END 434 435 UNSAFE_ENTRY(jobject, Unsafe_GetFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc)) { 436 assert(layoutKind != LayoutKind::REFERENCE, "This method handles only flat layouts"); 437 oop base = JNIHandles::resolve(obj); 438 if (base == nullptr) { 439 THROW_NULL(vmSymbols::java_lang_NullPointerException()); 440 } 441 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)); 442 InlineKlass* vk = InlineKlass::cast(k); 443 assert_and_log_unsafe_value_access(base, offset, vk); 444 LayoutKind lk = (LayoutKind)layoutKind; 445 Handle base_h(THREAD, base); 446 oop v = vk->read_payload_from_addr(base_h(), offset, lk, CHECK_NULL); 447 return JNIHandles::make_local(THREAD, v); 448 } UNSAFE_END 449 450 UNSAFE_ENTRY(void, Unsafe_PutValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jclass vc, jobject value)) { 451 oop base = JNIHandles::resolve(obj); 452 if (base == nullptr) { 453 THROW(vmSymbols::java_lang_NullPointerException()); 454 } 455 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)); 456 InlineKlass* vk = InlineKlass::cast(k); 457 assert(!base->is_inline_type() || base->mark().is_larval_state(), "must be an object instance or a larval inline type"); 458 assert_and_log_unsafe_value_access(base, offset, vk); 459 LayoutKind lk = LayoutKind::UNKNOWN; 460 if (base->is_array()) { 461 FlatArrayKlass* fak = FlatArrayKlass::cast(base->klass()); 462 lk = fak->layout_kind(); 463 } else { 464 fieldDescriptor fd; 465 InstanceKlass::cast(base->klass())->find_field_from_offset(offset, false, &fd); 466 lk = fd.field_holder()->inline_layout_info(fd.index()).kind(); 467 } 468 oop v = JNIHandles::resolve(value); 469 vk->write_value_to_addr(v, ((char*)(oopDesc*)base) + offset, lk, true, CHECK); 470 } UNSAFE_END 471 472 UNSAFE_ENTRY(void, Unsafe_PutFlatValue(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint layoutKind, jclass vc, jobject value)) { 473 assert(layoutKind != LayoutKind::REFERENCE, "This method handles only flat layouts"); 474 oop base = JNIHandles::resolve(obj); 475 if (base == nullptr) { 476 THROW(vmSymbols::java_lang_NullPointerException()); 477 } 478 Klass* k = java_lang_Class::as_Klass(JNIHandles::resolve_non_null(vc)); 479 InlineKlass* vk = InlineKlass::cast(k); 480 assert(!base->is_inline_type() || base->mark().is_larval_state(), "must be an object instance or a larval inline type"); 481 assert_and_log_unsafe_value_access(base, offset, vk); 482 LayoutKind lk = (LayoutKind)layoutKind; 483 oop v = JNIHandles::resolve(value); 484 vk->write_value_to_addr(v, ((char*)(oopDesc*)base) + offset, lk, true, CHECK); 485 } UNSAFE_END 486 487 UNSAFE_ENTRY(jobject, Unsafe_MakePrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) { 488 oop v = JNIHandles::resolve_non_null(value); 489 assert(v->is_inline_type(), "must be an inline type instance"); 490 Handle vh(THREAD, v); 491 InlineKlass* vk = InlineKlass::cast(v->klass()); 492 instanceOop new_value = vk->allocate_instance_buffer(CHECK_NULL); 493 vk->copy_payload_to_addr(vk->payload_addr(vh()), vk->payload_addr(new_value), LayoutKind::BUFFERED, false); 494 markWord mark = new_value->mark(); 495 new_value->set_mark(mark.enter_larval_state()); 496 return JNIHandles::make_local(THREAD, new_value); 497 } UNSAFE_END 498 499 UNSAFE_ENTRY(jobject, Unsafe_FinishPrivateBuffer(JNIEnv *env, jobject unsafe, jobject value)) { 500 oop v = JNIHandles::resolve(value); 501 assert(v->mark().is_larval_state(), "must be a larval value"); 502 markWord mark = v->mark(); 503 v->set_mark(mark.exit_larval_state()); 504 return JNIHandles::make_local(THREAD, v); 505 } UNSAFE_END 506 507 UNSAFE_ENTRY(jobject, Unsafe_GetReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { 508 oop p = JNIHandles::resolve(obj); 509 assert_field_offset_sane(p, offset); 510 oop v = HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_load_at(p, offset); 511 return JNIHandles::make_local(THREAD, v); 512 } UNSAFE_END 513 514 UNSAFE_ENTRY(void, Unsafe_PutReferenceVolatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject x_h)) { 515 oop x = JNIHandles::resolve(x_h); 516 oop p = JNIHandles::resolve(obj); 517 assert_field_offset_sane(p, offset); 518 HeapAccess<MO_SEQ_CST | ON_UNKNOWN_OOP_REF>::oop_store_at(p, offset, x); 519 } UNSAFE_END 520 521 UNSAFE_ENTRY(jobject, Unsafe_GetUncompressedObject(JNIEnv *env, jobject unsafe, jlong addr)) { 522 oop v = *(oop*) (address) addr; 523 return JNIHandles::make_local(THREAD, v); 524 } UNSAFE_END 525 526 #define DEFINE_GETSETOOP(java_type, Type) \ 527 \ 528 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \ 529 return MemoryAccess<java_type>(thread, obj, offset).get(); \ 530 } UNSAFE_END \ 531 \ 532 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \ 533 MemoryAccess<java_type>(thread, obj, offset).put(x); \ 534 } UNSAFE_END \ 535 \ 536 // END DEFINE_GETSETOOP. 537 538 DEFINE_GETSETOOP(jboolean, Boolean) 539 DEFINE_GETSETOOP(jbyte, Byte) 540 DEFINE_GETSETOOP(jshort, Short); 541 DEFINE_GETSETOOP(jchar, Char); 542 DEFINE_GETSETOOP(jint, Int); 543 DEFINE_GETSETOOP(jlong, Long); 544 DEFINE_GETSETOOP(jfloat, Float); 545 DEFINE_GETSETOOP(jdouble, Double); 546 547 #undef DEFINE_GETSETOOP 548 549 #define DEFINE_GETSETOOP_VOLATILE(java_type, Type) \ 550 \ 551 UNSAFE_ENTRY_SCOPED(java_type, Unsafe_Get##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset)) { \ 552 return MemoryAccess<java_type>(thread, obj, offset).get_volatile(); \ 553 } UNSAFE_END \ 554 \ 555 UNSAFE_ENTRY_SCOPED(void, Unsafe_Put##Type##Volatile(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, java_type x)) { \ 556 MemoryAccess<java_type>(thread, obj, offset).put_volatile(x); \ 557 } UNSAFE_END \ 558 \ 559 // END DEFINE_GETSETOOP_VOLATILE. 560 561 DEFINE_GETSETOOP_VOLATILE(jboolean, Boolean) 562 DEFINE_GETSETOOP_VOLATILE(jbyte, Byte) 563 DEFINE_GETSETOOP_VOLATILE(jshort, Short); 564 DEFINE_GETSETOOP_VOLATILE(jchar, Char); 565 DEFINE_GETSETOOP_VOLATILE(jint, Int); 566 DEFINE_GETSETOOP_VOLATILE(jlong, Long); 567 DEFINE_GETSETOOP_VOLATILE(jfloat, Float); 568 DEFINE_GETSETOOP_VOLATILE(jdouble, Double); 569 570 #undef DEFINE_GETSETOOP_VOLATILE 571 572 UNSAFE_LEAF(void, Unsafe_FullFence(JNIEnv *env, jobject unsafe)) { 573 OrderAccess::fence(); 574 } UNSAFE_END 575 576 ////// Allocation requests 577 578 UNSAFE_ENTRY(jobject, Unsafe_AllocateInstance(JNIEnv *env, jobject unsafe, jclass cls)) { 579 JvmtiVMObjectAllocEventCollector oam; 580 instanceOop i = InstanceKlass::allocate_instance(JNIHandles::resolve_non_null(cls), CHECK_NULL); 581 return JNIHandles::make_local(THREAD, i); 582 } UNSAFE_END 583 584 UNSAFE_LEAF(jlong, Unsafe_AllocateMemory0(JNIEnv *env, jobject unsafe, jlong size)) { 585 size_t sz = (size_t)size; 586 587 assert(is_aligned(sz, HeapWordSize), "sz not aligned"); 588 589 void* x = os::malloc(sz, mtOther); 590 591 return addr_to_java(x); 592 } UNSAFE_END 593 594 UNSAFE_LEAF(jlong, Unsafe_ReallocateMemory0(JNIEnv *env, jobject unsafe, jlong addr, jlong size)) { 595 void* p = addr_from_java(addr); 596 size_t sz = (size_t)size; 597 598 assert(is_aligned(sz, HeapWordSize), "sz not aligned"); 599 600 void* x = os::realloc(p, sz, mtOther); 601 602 return addr_to_java(x); 603 } UNSAFE_END 604 605 UNSAFE_LEAF(void, Unsafe_FreeMemory0(JNIEnv *env, jobject unsafe, jlong addr)) { 606 void* p = addr_from_java(addr); 607 608 os::free(p); 609 } UNSAFE_END 610 611 UNSAFE_ENTRY_SCOPED(void, Unsafe_SetMemory0(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong size, jbyte value)) { 612 size_t sz = (size_t)size; 613 614 oop base = JNIHandles::resolve(obj); 615 void* p = index_oop_from_field_offset_long(base, offset); 616 617 { 618 GuardUnsafeAccess guard(thread); 619 if (StubRoutines::unsafe_setmemory() != nullptr) { 620 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread)); 621 StubRoutines::UnsafeSetMemory_stub()(p, sz, value); 622 } else { 623 Copy::fill_to_memory_atomic(p, sz, value); 624 } 625 } 626 } UNSAFE_END 627 628 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopyMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size)) { 629 size_t sz = (size_t)size; 630 631 oop srcp = JNIHandles::resolve(srcObj); 632 oop dstp = JNIHandles::resolve(dstObj); 633 634 void* src = index_oop_from_field_offset_long(srcp, srcOffset); 635 void* dst = index_oop_from_field_offset_long(dstp, dstOffset); 636 { 637 GuardUnsafeAccess guard(thread); 638 if (StubRoutines::unsafe_arraycopy() != nullptr) { 639 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, thread)); 640 StubRoutines::UnsafeArrayCopy_stub()(src, dst, sz); 641 } else { 642 Copy::conjoint_memory_atomic(src, dst, sz); 643 } 644 } 645 } UNSAFE_END 646 647 UNSAFE_ENTRY_SCOPED(void, Unsafe_CopySwapMemory0(JNIEnv *env, jobject unsafe, jobject srcObj, jlong srcOffset, jobject dstObj, jlong dstOffset, jlong size, jlong elemSize)) { 648 size_t sz = (size_t)size; 649 size_t esz = (size_t)elemSize; 650 651 oop srcp = JNIHandles::resolve(srcObj); 652 oop dstp = JNIHandles::resolve(dstObj); 653 654 address src = (address)index_oop_from_field_offset_long(srcp, srcOffset); 655 address dst = (address)index_oop_from_field_offset_long(dstp, dstOffset); 656 657 { 658 GuardUnsafeAccess guard(thread); 659 Copy::conjoint_swap(src, dst, sz, esz); 660 } 661 } UNSAFE_END 662 663 UNSAFE_LEAF (void, Unsafe_WriteBack0(JNIEnv *env, jobject unsafe, jlong line)) { 664 assert(VM_Version::supports_data_cache_line_flush(), "should not get here"); 665 #ifdef ASSERT 666 if (TraceMemoryWriteback) { 667 tty->print_cr("Unsafe: writeback 0x%p", addr_from_java(line)); 668 } 669 #endif 670 671 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current())); 672 assert(StubRoutines::data_cache_writeback() != nullptr, "sanity"); 673 (StubRoutines::DataCacheWriteback_stub())(addr_from_java(line)); 674 } UNSAFE_END 675 676 static void doWriteBackSync0(bool is_pre) 677 { 678 MACOS_AARCH64_ONLY(ThreadWXEnable wx(WXExec, Thread::current())); 679 assert(StubRoutines::data_cache_writeback_sync() != nullptr, "sanity"); 680 (StubRoutines::DataCacheWritebackSync_stub())(is_pre); 681 } 682 683 UNSAFE_LEAF (void, Unsafe_WriteBackPreSync0(JNIEnv *env, jobject unsafe)) { 684 assert(VM_Version::supports_data_cache_line_flush(), "should not get here"); 685 #ifdef ASSERT 686 if (TraceMemoryWriteback) { 687 tty->print_cr("Unsafe: writeback pre-sync"); 688 } 689 #endif 690 691 doWriteBackSync0(true); 692 } UNSAFE_END 693 694 UNSAFE_LEAF (void, Unsafe_WriteBackPostSync0(JNIEnv *env, jobject unsafe)) { 695 assert(VM_Version::supports_data_cache_line_flush(), "should not get here"); 696 #ifdef ASSERT 697 if (TraceMemoryWriteback) { 698 tty->print_cr("Unsafe: writeback pre-sync"); 699 } 700 #endif 701 702 doWriteBackSync0(false); 703 } UNSAFE_END 704 705 ////// Random queries 706 707 static jlong find_field_offset(jclass clazz, jstring name, TRAPS) { 708 assert(clazz != nullptr, "clazz must not be null"); 709 assert(name != nullptr, "name must not be null"); 710 711 ResourceMark rm(THREAD); 712 char *utf_name = java_lang_String::as_utf8_string(JNIHandles::resolve_non_null(name)); 713 714 InstanceKlass* k = InstanceKlass::cast(java_lang_Class::as_Klass(JNIHandles::resolve_non_null(clazz))); 715 716 jint offset = -1; 717 for (JavaFieldStream fs(k); !fs.done(); fs.next()) { 718 Symbol *name = fs.name(); 719 if (name->equals(utf_name)) { 720 offset = fs.offset(); 721 break; 722 } 723 } 724 if (offset < 0) { 725 THROW_0(vmSymbols::java_lang_InternalError()); 726 } 727 return field_offset_from_byte_offset(offset); 728 } 729 730 static jlong find_field_offset(jobject field, int must_be_static, TRAPS) { 731 assert(field != nullptr, "field must not be null"); 732 733 oop reflected = JNIHandles::resolve_non_null(field); 734 oop mirror = java_lang_reflect_Field::clazz(reflected); 735 Klass* k = java_lang_Class::as_Klass(mirror); 736 int slot = java_lang_reflect_Field::slot(reflected); 737 int modifiers = java_lang_reflect_Field::modifiers(reflected); 738 739 if (must_be_static >= 0) { 740 int really_is_static = ((modifiers & JVM_ACC_STATIC) != 0); 741 if (must_be_static != really_is_static) { 742 THROW_0(vmSymbols::java_lang_IllegalArgumentException()); 743 } 744 } 745 746 int offset = InstanceKlass::cast(k)->field_offset(slot); 747 return field_offset_from_byte_offset(offset); 748 } 749 750 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) { 751 return find_field_offset(field, 0, THREAD); 752 } UNSAFE_END 753 754 UNSAFE_ENTRY(jlong, Unsafe_ObjectFieldOffset1(JNIEnv *env, jobject unsafe, jclass c, jstring name)) { 755 return find_field_offset(c, name, THREAD); 756 } UNSAFE_END 757 758 UNSAFE_ENTRY(jlong, Unsafe_StaticFieldOffset0(JNIEnv *env, jobject unsafe, jobject field)) { 759 return find_field_offset(field, 1, THREAD); 760 } UNSAFE_END 761 762 UNSAFE_ENTRY(jobject, Unsafe_StaticFieldBase0(JNIEnv *env, jobject unsafe, jobject field)) { 763 assert(field != nullptr, "field must not be null"); 764 765 // Note: In this VM implementation, a field address is always a short 766 // offset from the base of a klass metaobject. Thus, the full dynamic 767 // range of the return type is never used. However, some implementations 768 // might put the static field inside an array shared by many classes, 769 // or even at a fixed address, in which case the address could be quite 770 // large. In that last case, this function would return null, since 771 // the address would operate alone, without any base pointer. 772 773 oop reflected = JNIHandles::resolve_non_null(field); 774 oop mirror = java_lang_reflect_Field::clazz(reflected); 775 int modifiers = java_lang_reflect_Field::modifiers(reflected); 776 777 if ((modifiers & JVM_ACC_STATIC) == 0) { 778 THROW_NULL(vmSymbols::java_lang_IllegalArgumentException()); 779 } 780 781 return JNIHandles::make_local(THREAD, mirror); 782 } UNSAFE_END 783 784 UNSAFE_ENTRY(void, Unsafe_EnsureClassInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) { 785 assert(clazz != nullptr, "clazz must not be null"); 786 787 oop mirror = JNIHandles::resolve_non_null(clazz); 788 789 Klass* klass = java_lang_Class::as_Klass(mirror); 790 if (klass != nullptr && klass->should_be_initialized()) { 791 InstanceKlass* k = InstanceKlass::cast(klass); 792 k->initialize(CHECK); 793 } 794 } 795 UNSAFE_END 796 797 UNSAFE_ENTRY(jboolean, Unsafe_ShouldBeInitialized0(JNIEnv *env, jobject unsafe, jobject clazz)) { 798 assert(clazz != nullptr, "clazz must not be null"); 799 800 oop mirror = JNIHandles::resolve_non_null(clazz); 801 Klass* klass = java_lang_Class::as_Klass(mirror); 802 803 if (klass != nullptr && klass->should_be_initialized()) { 804 return true; 805 } 806 807 return false; 808 } 809 UNSAFE_END 810 811 static void getBaseAndScale(int& base, int& scale, jclass clazz, TRAPS) { 812 assert(clazz != nullptr, "clazz must not be null"); 813 814 oop mirror = JNIHandles::resolve_non_null(clazz); 815 Klass* k = java_lang_Class::as_Klass(mirror); 816 817 if (k == nullptr || !k->is_array_klass()) { 818 THROW(vmSymbols::java_lang_InvalidClassException()); 819 } else if (k->is_objArray_klass()) { 820 base = arrayOopDesc::base_offset_in_bytes(T_OBJECT); 821 scale = heapOopSize; 822 } else if (k->is_typeArray_klass()) { 823 TypeArrayKlass* tak = TypeArrayKlass::cast(k); 824 base = tak->array_header_in_bytes(); 825 assert(base == arrayOopDesc::base_offset_in_bytes(tak->element_type()), "array_header_size semantics ok"); 826 scale = (1 << tak->log2_element_size()); 827 } else if (k->is_flatArray_klass()) { 828 FlatArrayKlass* vak = FlatArrayKlass::cast(k); 829 InlineKlass* vklass = vak->element_klass(); 830 base = vak->array_header_in_bytes(); 831 scale = vak->element_byte_size(); 832 } else { 833 ShouldNotReachHere(); 834 } 835 } 836 837 UNSAFE_ENTRY(jint, Unsafe_ArrayBaseOffset0(JNIEnv *env, jobject unsafe, jclass clazz)) { 838 int base = 0, scale = 0; 839 getBaseAndScale(base, scale, clazz, CHECK_0); 840 841 return field_offset_from_byte_offset(base); 842 } UNSAFE_END 843 844 845 UNSAFE_ENTRY(jint, Unsafe_ArrayIndexScale0(JNIEnv *env, jobject unsafe, jclass clazz)) { 846 int base = 0, scale = 0; 847 getBaseAndScale(base, scale, clazz, CHECK_0); 848 849 // This VM packs both fields and array elements down to the byte. 850 // But watch out: If this changes, so that array references for 851 // a given primitive type (say, T_BOOLEAN) use different memory units 852 // than fields, this method MUST return zero for such arrays. 853 // For example, the VM used to store sub-word sized fields in full 854 // words in the object layout, so that accessors like getByte(Object,int) 855 // did not really do what one might expect for arrays. Therefore, 856 // this function used to report a zero scale factor, so that the user 857 // would know not to attempt to access sub-word array elements. 858 // // Code for unpacked fields: 859 // if (scale < wordSize) return 0; 860 861 // The following allows for a pretty general fieldOffset cookie scheme, 862 // but requires it to be linear in byte offset. 863 return field_offset_from_byte_offset(scale) - field_offset_from_byte_offset(0); 864 } UNSAFE_END 865 866 867 UNSAFE_ENTRY(jlong, Unsafe_GetObjectSize0(JNIEnv* env, jobject o, jobject obj)) 868 oop p = JNIHandles::resolve(obj); 869 return p->size() * HeapWordSize; 870 UNSAFE_END 871 872 873 static inline void throw_new(JNIEnv *env, const char *ename) { 874 jclass cls = env->FindClass(ename); 875 if (env->ExceptionCheck()) { 876 env->ExceptionClear(); 877 tty->print_cr("Unsafe: cannot throw %s because FindClass has failed", ename); 878 return; 879 } 880 881 env->ThrowNew(cls, nullptr); 882 } 883 884 static jclass Unsafe_DefineClass_impl(JNIEnv *env, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd) { 885 // Code lifted from JDK 1.3 ClassLoader.c 886 887 jbyte *body; 888 char *utfName = nullptr; 889 jclass result = nullptr; 890 char buf[128]; 891 892 assert(data != nullptr, "Class bytes must not be null"); 893 assert(length >= 0, "length must not be negative: %d", length); 894 895 if (UsePerfData) { 896 ClassLoader::unsafe_defineClassCallCounter()->inc(); 897 } 898 899 body = NEW_C_HEAP_ARRAY_RETURN_NULL(jbyte, length, mtInternal); 900 if (body == nullptr) { 901 throw_new(env, "java/lang/OutOfMemoryError"); 902 return nullptr; 903 } 904 905 env->GetByteArrayRegion(data, offset, length, body); 906 if (env->ExceptionCheck()) { 907 goto free_body; 908 } 909 910 if (name != nullptr) { 911 uint len = env->GetStringUTFLength(name); 912 int unicode_len = env->GetStringLength(name); 913 914 if (len >= sizeof(buf)) { 915 utfName = NEW_C_HEAP_ARRAY_RETURN_NULL(char, len + 1, mtInternal); 916 if (utfName == nullptr) { 917 throw_new(env, "java/lang/OutOfMemoryError"); 918 goto free_body; 919 } 920 } else { 921 utfName = buf; 922 } 923 924 env->GetStringUTFRegion(name, 0, unicode_len, utfName); 925 926 for (uint i = 0; i < len; i++) { 927 if (utfName[i] == '.') utfName[i] = '/'; 928 } 929 } 930 931 result = JVM_DefineClass(env, utfName, loader, body, length, pd); 932 933 if (utfName && utfName != buf) { 934 FREE_C_HEAP_ARRAY(char, utfName); 935 } 936 937 free_body: 938 FREE_C_HEAP_ARRAY(jbyte, body); 939 return result; 940 } 941 942 943 UNSAFE_ENTRY(jclass, Unsafe_DefineClass0(JNIEnv *env, jobject unsafe, jstring name, jbyteArray data, int offset, int length, jobject loader, jobject pd)) { 944 ThreadToNativeFromVM ttnfv(thread); 945 946 return Unsafe_DefineClass_impl(env, name, data, offset, length, loader, pd); 947 } UNSAFE_END 948 949 950 UNSAFE_ENTRY(void, Unsafe_ThrowException(JNIEnv *env, jobject unsafe, jthrowable thr)) { 951 ThreadToNativeFromVM ttnfv(thread); 952 env->Throw(thr); 953 } UNSAFE_END 954 955 // JSR166 ------------------------------------------------------------------ 956 957 UNSAFE_ENTRY(jobject, Unsafe_CompareAndExchangeReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) { 958 oop x = JNIHandles::resolve(x_h); 959 oop e = JNIHandles::resolve(e_h); 960 oop p = JNIHandles::resolve(obj); 961 assert_field_offset_sane(p, offset); 962 oop res = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x); 963 return JNIHandles::make_local(THREAD, res); 964 } UNSAFE_END 965 966 UNSAFE_ENTRY_SCOPED(jint, Unsafe_CompareAndExchangeInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) { 967 oop p = JNIHandles::resolve(obj); 968 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset); 969 return Atomic::cmpxchg(addr, e, x); 970 } UNSAFE_END 971 972 UNSAFE_ENTRY_SCOPED(jlong, Unsafe_CompareAndExchangeLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) { 973 oop p = JNIHandles::resolve(obj); 974 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset); 975 return Atomic::cmpxchg(addr, e, x); 976 } UNSAFE_END 977 978 UNSAFE_ENTRY(jboolean, Unsafe_CompareAndSetReference(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jobject e_h, jobject x_h)) { 979 oop x = JNIHandles::resolve(x_h); 980 oop e = JNIHandles::resolve(e_h); 981 oop p = JNIHandles::resolve(obj); 982 assert_field_offset_sane(p, offset); 983 oop ret = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_atomic_cmpxchg_at(p, (ptrdiff_t)offset, e, x); 984 return ret == e; 985 } UNSAFE_END 986 987 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetInt(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jint e, jint x)) { 988 oop p = JNIHandles::resolve(obj); 989 volatile jint* addr = (volatile jint*)index_oop_from_field_offset_long(p, offset); 990 return Atomic::cmpxchg(addr, e, x) == e; 991 } UNSAFE_END 992 993 UNSAFE_ENTRY_SCOPED(jboolean, Unsafe_CompareAndSetLong(JNIEnv *env, jobject unsafe, jobject obj, jlong offset, jlong e, jlong x)) { 994 oop p = JNIHandles::resolve(obj); 995 volatile jlong* addr = (volatile jlong*)index_oop_from_field_offset_long(p, offset); 996 return Atomic::cmpxchg(addr, e, x) == e; 997 } UNSAFE_END 998 999 static void post_thread_park_event(EventThreadPark* event, const oop obj, jlong timeout_nanos, jlong until_epoch_millis) { 1000 assert(event != nullptr, "invariant"); 1001 event->set_parkedClass((obj != nullptr) ? obj->klass() : nullptr); 1002 event->set_timeout(timeout_nanos); 1003 event->set_until(until_epoch_millis); 1004 event->set_address((obj != nullptr) ? (u8)cast_from_oop<uintptr_t>(obj) : 0); 1005 event->commit(); 1006 } 1007 1008 UNSAFE_ENTRY(void, Unsafe_Park(JNIEnv *env, jobject unsafe, jboolean isAbsolute, jlong time)) { 1009 HOTSPOT_THREAD_PARK_BEGIN((uintptr_t) thread->parker(), (int) isAbsolute, time); 1010 EventThreadPark event; 1011 1012 JavaThreadParkedState jtps(thread, time != 0); 1013 thread->parker()->park(isAbsolute != 0, time); 1014 if (event.should_commit()) { 1015 const oop obj = thread->current_park_blocker(); 1016 if (time == 0) { 1017 post_thread_park_event(&event, obj, min_jlong, min_jlong); 1018 } else { 1019 if (isAbsolute != 0) { 1020 post_thread_park_event(&event, obj, min_jlong, time); 1021 } else { 1022 post_thread_park_event(&event, obj, time, min_jlong); 1023 } 1024 } 1025 } 1026 HOTSPOT_THREAD_PARK_END((uintptr_t) thread->parker()); 1027 } UNSAFE_END 1028 1029 UNSAFE_ENTRY(void, Unsafe_Unpark(JNIEnv *env, jobject unsafe, jobject jthread)) { 1030 if (jthread != nullptr) { 1031 oop thread_oop = JNIHandles::resolve_non_null(jthread); 1032 // Get the JavaThread* stored in the java.lang.Thread object _before_ 1033 // the embedded ThreadsListHandle is constructed so we know if the 1034 // early life stage of the JavaThread* is protected. We use acquire 1035 // here to ensure that if we see a non-nullptr value, then we also 1036 // see the main ThreadsList updates from the JavaThread* being added. 1037 FastThreadsListHandle ftlh(thread_oop, java_lang_Thread::thread_acquire(thread_oop)); 1038 JavaThread* thr = ftlh.protected_java_thread(); 1039 if (thr != nullptr) { 1040 // The still live JavaThread* is protected by the FastThreadsListHandle 1041 // so it is safe to access. 1042 Parker* p = thr->parker(); 1043 HOTSPOT_THREAD_UNPARK((uintptr_t) p); 1044 p->unpark(); 1045 } 1046 } // FastThreadsListHandle is destroyed here. 1047 } UNSAFE_END 1048 1049 UNSAFE_ENTRY(jint, Unsafe_GetLoadAverage0(JNIEnv *env, jobject unsafe, jdoubleArray loadavg, jint nelem)) { 1050 const int max_nelem = 3; 1051 double la[max_nelem]; 1052 jint ret; 1053 1054 typeArrayOop a = typeArrayOop(JNIHandles::resolve_non_null(loadavg)); 1055 assert(a->is_typeArray(), "must be type array"); 1056 1057 ret = os::loadavg(la, nelem); 1058 if (ret == -1) { 1059 return -1; 1060 } 1061 1062 // if successful, ret is the number of samples actually retrieved. 1063 assert(ret >= 0 && ret <= max_nelem, "Unexpected loadavg return value"); 1064 switch(ret) { 1065 case 3: a->double_at_put(2, (jdouble)la[2]); // fall through 1066 case 2: a->double_at_put(1, (jdouble)la[1]); // fall through 1067 case 1: a->double_at_put(0, (jdouble)la[0]); break; 1068 } 1069 1070 return ret; 1071 } UNSAFE_END 1072 1073 1074 /// JVM_RegisterUnsafeMethods 1075 1076 #define ADR "J" 1077 1078 #define LANG "Ljava/lang/" 1079 1080 #define OBJ LANG "Object;" 1081 #define CLS LANG "Class;" 1082 #define FLD LANG "reflect/Field;" 1083 #define THR LANG "Throwable;" 1084 1085 #define DC_Args LANG "String;[BII" LANG "ClassLoader;" "Ljava/security/ProtectionDomain;" 1086 #define DAC_Args CLS "[B[" OBJ 1087 1088 #define CC (char*) /*cast a literal from (const char*)*/ 1089 #define FN_PTR(f) CAST_FROM_FN_PTR(void*, &f) 1090 1091 #define DECLARE_GETPUTOOP(Type, Desc) \ 1092 {CC "get" #Type, CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type)}, \ 1093 {CC "put" #Type, CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type)}, \ 1094 {CC "get" #Type "Volatile", CC "(" OBJ "J)" #Desc, FN_PTR(Unsafe_Get##Type##Volatile)}, \ 1095 {CC "put" #Type "Volatile", CC "(" OBJ "J" #Desc ")V", FN_PTR(Unsafe_Put##Type##Volatile)} 1096 1097 1098 static JNINativeMethod jdk_internal_misc_Unsafe_methods[] = { 1099 {CC "getReference", CC "(" OBJ "J)" OBJ "", FN_PTR(Unsafe_GetReference)}, 1100 {CC "putReference", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReference)}, 1101 {CC "getReferenceVolatile", CC "(" OBJ "J)" OBJ, FN_PTR(Unsafe_GetReferenceVolatile)}, 1102 {CC "putReferenceVolatile", CC "(" OBJ "J" OBJ ")V", FN_PTR(Unsafe_PutReferenceVolatile)}, 1103 1104 {CC "isFlatArray", CC "(" CLS ")Z", FN_PTR(Unsafe_IsFlatArray)}, 1105 {CC "isFlatField0", CC "(" OBJ ")Z", FN_PTR(Unsafe_IsFlatField)}, 1106 {CC "hasNullMarker0", CC "(" OBJ ")Z", FN_PTR(Unsafe_HasNullMarker)}, 1107 {CC "nullMarkerOffset0", CC "(" OBJ ")I", FN_PTR(Unsafe_NullMarkerOffset)}, 1108 {CC "arrayLayout0", CC "(" OBJ ")I", FN_PTR(Unsafe_ArrayLayout)}, 1109 {CC "fieldLayout0", CC "(" OBJ ")I", FN_PTR(Unsafe_FieldLayout)}, 1110 {CC "getValue", CC "(" OBJ "J" CLS ")" OBJ, FN_PTR(Unsafe_GetValue)}, 1111 {CC "getFlatValue", CC "(" OBJ "JI" CLS ")" OBJ, FN_PTR(Unsafe_GetFlatValue)}, 1112 {CC "putValue", CC "(" OBJ "J" CLS OBJ ")V", FN_PTR(Unsafe_PutValue)}, 1113 {CC "putFlatValue", CC "(" OBJ "JI" CLS OBJ ")V", FN_PTR(Unsafe_PutFlatValue)}, 1114 {CC "makePrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_MakePrivateBuffer)}, 1115 {CC "finishPrivateBuffer", CC "(" OBJ ")" OBJ, FN_PTR(Unsafe_FinishPrivateBuffer)}, 1116 {CC "valueHeaderSize", CC "(" CLS ")J", FN_PTR(Unsafe_ValueHeaderSize)}, 1117 1118 {CC "getUncompressedObject", CC "(" ADR ")" OBJ, FN_PTR(Unsafe_GetUncompressedObject)}, 1119 1120 DECLARE_GETPUTOOP(Boolean, Z), 1121 DECLARE_GETPUTOOP(Byte, B), 1122 DECLARE_GETPUTOOP(Short, S), 1123 DECLARE_GETPUTOOP(Char, C), 1124 DECLARE_GETPUTOOP(Int, I), 1125 DECLARE_GETPUTOOP(Long, J), 1126 DECLARE_GETPUTOOP(Float, F), 1127 DECLARE_GETPUTOOP(Double, D), 1128 1129 {CC "allocateMemory0", CC "(J)" ADR, FN_PTR(Unsafe_AllocateMemory0)}, 1130 {CC "reallocateMemory0", CC "(" ADR "J)" ADR, FN_PTR(Unsafe_ReallocateMemory0)}, 1131 {CC "freeMemory0", CC "(" ADR ")V", FN_PTR(Unsafe_FreeMemory0)}, 1132 1133 {CC "objectFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_ObjectFieldOffset0)}, 1134 {CC "objectFieldOffset1", CC "(" CLS LANG "String;)J", FN_PTR(Unsafe_ObjectFieldOffset1)}, 1135 {CC "staticFieldOffset0", CC "(" FLD ")J", FN_PTR(Unsafe_StaticFieldOffset0)}, 1136 {CC "staticFieldBase0", CC "(" FLD ")" OBJ, FN_PTR(Unsafe_StaticFieldBase0)}, 1137 {CC "ensureClassInitialized0", CC "(" CLS ")V", FN_PTR(Unsafe_EnsureClassInitialized0)}, 1138 {CC "arrayBaseOffset0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayBaseOffset0)}, 1139 {CC "arrayIndexScale0", CC "(" CLS ")I", FN_PTR(Unsafe_ArrayIndexScale0)}, 1140 {CC "getObjectSize0", CC "(Ljava/lang/Object;)J", FN_PTR(Unsafe_GetObjectSize0)}, 1141 1142 {CC "defineClass0", CC "(" DC_Args ")" CLS, FN_PTR(Unsafe_DefineClass0)}, 1143 {CC "allocateInstance", CC "(" CLS ")" OBJ, FN_PTR(Unsafe_AllocateInstance)}, 1144 {CC "throwException", CC "(" THR ")V", FN_PTR(Unsafe_ThrowException)}, 1145 {CC "compareAndSetReference",CC "(" OBJ "J" OBJ "" OBJ ")Z", FN_PTR(Unsafe_CompareAndSetReference)}, 1146 {CC "compareAndSetInt", CC "(" OBJ "J""I""I"")Z", FN_PTR(Unsafe_CompareAndSetInt)}, 1147 {CC "compareAndSetLong", CC "(" OBJ "J""J""J"")Z", FN_PTR(Unsafe_CompareAndSetLong)}, 1148 {CC "compareAndExchangeReference", CC "(" OBJ "J" OBJ "" OBJ ")" OBJ, FN_PTR(Unsafe_CompareAndExchangeReference)}, 1149 {CC "compareAndExchangeInt", CC "(" OBJ "J""I""I"")I", FN_PTR(Unsafe_CompareAndExchangeInt)}, 1150 {CC "compareAndExchangeLong", CC "(" OBJ "J""J""J"")J", FN_PTR(Unsafe_CompareAndExchangeLong)}, 1151 1152 {CC "park", CC "(ZJ)V", FN_PTR(Unsafe_Park)}, 1153 {CC "unpark", CC "(" OBJ ")V", FN_PTR(Unsafe_Unpark)}, 1154 1155 {CC "getLoadAverage0", CC "([DI)I", FN_PTR(Unsafe_GetLoadAverage0)}, 1156 1157 {CC "copyMemory0", CC "(" OBJ "J" OBJ "JJ)V", FN_PTR(Unsafe_CopyMemory0)}, 1158 {CC "copySwapMemory0", CC "(" OBJ "J" OBJ "JJJ)V", FN_PTR(Unsafe_CopySwapMemory0)}, 1159 {CC "writeback0", CC "(" "J" ")V", FN_PTR(Unsafe_WriteBack0)}, 1160 {CC "writebackPreSync0", CC "()V", FN_PTR(Unsafe_WriteBackPreSync0)}, 1161 {CC "writebackPostSync0", CC "()V", FN_PTR(Unsafe_WriteBackPostSync0)}, 1162 {CC "setMemory0", CC "(" OBJ "JJB)V", FN_PTR(Unsafe_SetMemory0)}, 1163 1164 {CC "shouldBeInitialized0", CC "(" CLS ")Z", FN_PTR(Unsafe_ShouldBeInitialized0)}, 1165 1166 {CC "fullFence", CC "()V", FN_PTR(Unsafe_FullFence)}, 1167 }; 1168 1169 #undef CC 1170 #undef FN_PTR 1171 1172 #undef ADR 1173 #undef LANG 1174 #undef OBJ 1175 #undef CLS 1176 #undef FLD 1177 #undef THR 1178 #undef DC_Args 1179 #undef DAC_Args 1180 1181 #undef DECLARE_GETPUTOOP 1182 1183 1184 // This function is exported, used by NativeLookup. 1185 // The Unsafe_xxx functions above are called only from the interpreter. 1186 // The optimizer looks at names and signatures to recognize 1187 // individual functions. 1188 1189 JVM_ENTRY(void, JVM_RegisterJDKInternalMiscUnsafeMethods(JNIEnv *env, jclass unsafeclass)) { 1190 ThreadToNativeFromVM ttnfv(thread); 1191 1192 int ok = env->RegisterNatives(unsafeclass, jdk_internal_misc_Unsafe_methods, sizeof(jdk_internal_misc_Unsafe_methods)/sizeof(JNINativeMethod)); 1193 guarantee(ok == 0, "register jdk.internal.misc.Unsafe natives"); 1194 } JVM_END