1 /*
   2  * Copyright (c) 1997, 2018, 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 "jvm.h"
  27 #include "classfile/classLoader.hpp"
  28 #include "classfile/javaClasses.hpp"
  29 #include "classfile/moduleEntry.hpp"
  30 #include "classfile/systemDictionary.hpp"
  31 #include "classfile/vmSymbols.hpp"
  32 #include "code/codeCache.hpp"
  33 #include "code/icBuffer.hpp"
  34 #include "code/vtableStubs.hpp"
  35 #include "gc/shared/vmGCOperations.hpp"
  36 #include "logging/log.hpp"
  37 #include "interpreter/interpreter.hpp"
  38 #include "logging/log.hpp"
  39 #include "logging/logStream.hpp"
  40 #include "memory/allocation.inline.hpp"
  41 #ifdef ASSERT
  42 #include "memory/guardedMemory.hpp"
  43 #endif
  44 #include "memory/resourceArea.hpp"
  45 #include "oops/oop.inline.hpp"
  46 #include "prims/jvm_misc.hpp"
  47 #include "prims/privilegedStack.hpp"
  48 #include "runtime/arguments.hpp"
  49 #include "runtime/atomic.hpp"
  50 #include "runtime/frame.inline.hpp"
  51 #include "runtime/interfaceSupport.hpp"
  52 #include "runtime/java.hpp"
  53 #include "runtime/javaCalls.hpp"
  54 #include "runtime/mutexLocker.hpp"
  55 #include "runtime/os.inline.hpp"
  56 #include "runtime/stubRoutines.hpp"
  57 #include "runtime/thread.inline.hpp"
  58 #include "runtime/threadSMR.hpp"
  59 #include "runtime/vm_version.hpp"
  60 #include "services/attachListener.hpp"
  61 #include "services/mallocTracker.hpp"
  62 #include "services/memTracker.hpp"
  63 #include "services/nmtCommon.hpp"
  64 #include "services/threadService.hpp"
  65 #include "utilities/align.hpp"
  66 #include "utilities/defaultStream.hpp"
  67 #include "utilities/events.hpp"
  68 
  69 # include <signal.h>
  70 # include <errno.h>
  71 
  72 OSThread*         os::_starting_thread    = NULL;
  73 address           os::_polling_page       = NULL;
  74 volatile int32_t* os::_mem_serialize_page = NULL;
  75 uintptr_t         os::_serialize_page_mask = 0;
  76 volatile unsigned int os::_rand_seed      = 1;
  77 int               os::_processor_count    = 0;
  78 int               os::_initial_active_processor_count = 0;
  79 size_t            os::_page_sizes[os::page_sizes_max];
  80 
  81 #ifndef PRODUCT
  82 julong os::num_mallocs = 0;         // # of calls to malloc/realloc
  83 julong os::alloc_bytes = 0;         // # of bytes allocated
  84 julong os::num_frees = 0;           // # of calls to free
  85 julong os::free_bytes = 0;          // # of bytes freed
  86 #endif
  87 
  88 static size_t cur_malloc_words = 0;  // current size for MallocMaxTestWords
  89 
  90 void os_init_globals() {
  91   // Called from init_globals().
  92   // See Threads::create_vm() in thread.cpp, and init.cpp.
  93   os::init_globals();
  94 }
  95 
  96 static time_t get_timezone(const struct tm* time_struct) {
  97 #if defined(_ALLBSD_SOURCE)
  98   return time_struct->tm_gmtoff;
  99 #elif defined(_WINDOWS)
 100   long zone;
 101   _get_timezone(&zone);
 102   return static_cast<time_t>(zone);
 103 #else
 104   return timezone;
 105 #endif
 106 }
 107 
 108 int os::snprintf(char* buf, size_t len, const char* fmt, ...) {
 109   va_list args;
 110   va_start(args, fmt);
 111   int result = os::vsnprintf(buf, len, fmt, args);
 112   va_end(args);
 113   return result;
 114 }
 115 
 116 // Fill in buffer with current local time as an ISO-8601 string.
 117 // E.g., yyyy-mm-ddThh:mm:ss-zzzz.
 118 // Returns buffer, or NULL if it failed.
 119 // This would mostly be a call to
 120 //     strftime(...., "%Y-%m-%d" "T" "%H:%M:%S" "%z", ....)
 121 // except that on Windows the %z behaves badly, so we do it ourselves.
 122 // Also, people wanted milliseconds on there,
 123 // and strftime doesn't do milliseconds.
 124 char* os::iso8601_time(char* buffer, size_t buffer_length, bool utc) {
 125   // Output will be of the form "YYYY-MM-DDThh:mm:ss.mmm+zzzz\0"
 126   //                                      1         2
 127   //                             12345678901234567890123456789
 128   // format string: "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d"
 129   static const size_t needed_buffer = 29;
 130 
 131   // Sanity check the arguments
 132   if (buffer == NULL) {
 133     assert(false, "NULL buffer");
 134     return NULL;
 135   }
 136   if (buffer_length < needed_buffer) {
 137     assert(false, "buffer_length too small");
 138     return NULL;
 139   }
 140   // Get the current time
 141   jlong milliseconds_since_19700101 = javaTimeMillis();
 142   const int milliseconds_per_microsecond = 1000;
 143   const time_t seconds_since_19700101 =
 144     milliseconds_since_19700101 / milliseconds_per_microsecond;
 145   const int milliseconds_after_second =
 146     milliseconds_since_19700101 % milliseconds_per_microsecond;
 147   // Convert the time value to a tm and timezone variable
 148   struct tm time_struct;
 149   if (utc) {
 150     if (gmtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 151       assert(false, "Failed gmtime_pd");
 152       return NULL;
 153     }
 154   } else {
 155     if (localtime_pd(&seconds_since_19700101, &time_struct) == NULL) {
 156       assert(false, "Failed localtime_pd");
 157       return NULL;
 158     }
 159   }
 160   const time_t zone = get_timezone(&time_struct);
 161 
 162   // If daylight savings time is in effect,
 163   // we are 1 hour East of our time zone
 164   const time_t seconds_per_minute = 60;
 165   const time_t minutes_per_hour = 60;
 166   const time_t seconds_per_hour = seconds_per_minute * minutes_per_hour;
 167   time_t UTC_to_local = zone;
 168   if (time_struct.tm_isdst > 0) {
 169     UTC_to_local = UTC_to_local - seconds_per_hour;
 170   }
 171 
 172   // No offset when dealing with UTC
 173   if (utc) {
 174     UTC_to_local = 0;
 175   }
 176 
 177   // Compute the time zone offset.
 178   //    localtime_pd() sets timezone to the difference (in seconds)
 179   //    between UTC and and local time.
 180   //    ISO 8601 says we need the difference between local time and UTC,
 181   //    we change the sign of the localtime_pd() result.
 182   const time_t local_to_UTC = -(UTC_to_local);
 183   // Then we have to figure out if if we are ahead (+) or behind (-) UTC.
 184   char sign_local_to_UTC = '+';
 185   time_t abs_local_to_UTC = local_to_UTC;
 186   if (local_to_UTC < 0) {
 187     sign_local_to_UTC = '-';
 188     abs_local_to_UTC = -(abs_local_to_UTC);
 189   }
 190   // Convert time zone offset seconds to hours and minutes.
 191   const time_t zone_hours = (abs_local_to_UTC / seconds_per_hour);
 192   const time_t zone_min =
 193     ((abs_local_to_UTC % seconds_per_hour) / seconds_per_minute);
 194 
 195   // Print an ISO 8601 date and time stamp into the buffer
 196   const int year = 1900 + time_struct.tm_year;
 197   const int month = 1 + time_struct.tm_mon;
 198   const int printed = jio_snprintf(buffer, buffer_length,
 199                                    "%04d-%02d-%02dT%02d:%02d:%02d.%03d%c%02d%02d",
 200                                    year,
 201                                    month,
 202                                    time_struct.tm_mday,
 203                                    time_struct.tm_hour,
 204                                    time_struct.tm_min,
 205                                    time_struct.tm_sec,
 206                                    milliseconds_after_second,
 207                                    sign_local_to_UTC,
 208                                    zone_hours,
 209                                    zone_min);
 210   if (printed == 0) {
 211     assert(false, "Failed jio_printf");
 212     return NULL;
 213   }
 214   return buffer;
 215 }
 216 
 217 OSReturn os::set_priority(Thread* thread, ThreadPriority p) {
 218   debug_only(Thread::check_for_dangling_thread_pointer(thread);)
 219 
 220   if (p >= MinPriority && p <= MaxPriority) {
 221     int priority = java_to_os_priority[p];
 222     return set_native_priority(thread, priority);
 223   } else {
 224     assert(false, "Should not happen");
 225     return OS_ERR;
 226   }
 227 }
 228 
 229 // The mapping from OS priority back to Java priority may be inexact because
 230 // Java priorities can map M:1 with native priorities. If you want the definite
 231 // Java priority then use JavaThread::java_priority()
 232 OSReturn os::get_priority(const Thread* const thread, ThreadPriority& priority) {
 233   int p;
 234   int os_prio;
 235   OSReturn ret = get_native_priority(thread, &os_prio);
 236   if (ret != OS_OK) return ret;
 237 
 238   if (java_to_os_priority[MaxPriority] > java_to_os_priority[MinPriority]) {
 239     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] > os_prio; p--) ;
 240   } else {
 241     // niceness values are in reverse order
 242     for (p = MaxPriority; p > MinPriority && java_to_os_priority[p] < os_prio; p--) ;
 243   }
 244   priority = (ThreadPriority)p;
 245   return OS_OK;
 246 }
 247 
 248 bool os::dll_build_name(char* buffer, size_t size, const char* fname) {
 249   int n = jio_snprintf(buffer, size, "%s%s%s", JNI_LIB_PREFIX, fname, JNI_LIB_SUFFIX);
 250   return (n != -1);
 251 }
 252 
 253 // Helper for dll_locate_lib.
 254 // Pass buffer and printbuffer as we already printed the path to buffer
 255 // when we called get_current_directory. This way we avoid another buffer
 256 // of size MAX_PATH.
 257 static bool conc_path_file_and_check(char *buffer, char *printbuffer, size_t printbuflen,
 258                                      const char* pname, char lastchar, const char* fname) {
 259 
 260   // Concatenate path and file name, but don't print double path separators.
 261   const char *filesep = (WINDOWS_ONLY(lastchar == ':' ||) lastchar == os::file_separator()[0]) ?
 262                         "" : os::file_separator();
 263   int ret = jio_snprintf(printbuffer, printbuflen, "%s%s%s", pname, filesep, fname);
 264   // Check whether file exists.
 265   if (ret != -1) {
 266     struct stat statbuf;
 267     return os::stat(buffer, &statbuf) == 0;
 268   }
 269   return false;
 270 }
 271 
 272 bool os::dll_locate_lib(char *buffer, size_t buflen,
 273                         const char* pname, const char* fname) {
 274   bool retval = false;
 275 
 276   size_t fullfnamelen = strlen(JNI_LIB_PREFIX) + strlen(fname) + strlen(JNI_LIB_SUFFIX);
 277   char* fullfname = (char*)NEW_C_HEAP_ARRAY(char, fullfnamelen + 1, mtInternal);
 278   if (dll_build_name(fullfname, fullfnamelen + 1, fname)) {
 279     const size_t pnamelen = pname ? strlen(pname) : 0;
 280 
 281     if (pnamelen == 0) {
 282       // If no path given, use current working directory.
 283       const char* p = get_current_directory(buffer, buflen);
 284       if (p != NULL) {
 285         const size_t plen = strlen(buffer);
 286         const char lastchar = buffer[plen - 1];
 287         retval = conc_path_file_and_check(buffer, &buffer[plen], buflen - plen,
 288                                           "", lastchar, fullfname);
 289       }
 290     } else if (strchr(pname, *os::path_separator()) != NULL) {
 291       // A list of paths. Search for the path that contains the library.
 292       int n;
 293       char** pelements = split_path(pname, &n);
 294       if (pelements != NULL) {
 295         for (int i = 0; i < n; i++) {
 296           char* path = pelements[i];
 297           // Really shouldn't be NULL, but check can't hurt.
 298           size_t plen = (path == NULL) ? 0 : strlen(path);
 299           if (plen == 0) {
 300             continue; // Skip the empty path values.
 301           }
 302           const char lastchar = path[plen - 1];
 303           retval = conc_path_file_and_check(buffer, buffer, buflen, path, lastchar, fullfname);
 304           if (retval) break;
 305         }
 306         // Release the storage allocated by split_path.
 307         for (int i = 0; i < n; i++) {
 308           if (pelements[i] != NULL) {
 309             FREE_C_HEAP_ARRAY(char, pelements[i]);
 310           }
 311         }
 312         FREE_C_HEAP_ARRAY(char*, pelements);
 313       }
 314     } else {
 315       // A definite path.
 316       const char lastchar = pname[pnamelen-1];
 317       retval = conc_path_file_and_check(buffer, buffer, buflen, pname, lastchar, fullfname);
 318     }
 319   }
 320 
 321   FREE_C_HEAP_ARRAY(char*, fullfname);
 322   return retval;
 323 }
 324 
 325 // --------------------- sun.misc.Signal (optional) ---------------------
 326 
 327 
 328 // SIGBREAK is sent by the keyboard to query the VM state
 329 #ifndef SIGBREAK
 330 #define SIGBREAK SIGQUIT
 331 #endif
 332 
 333 // sigexitnum_pd is a platform-specific special signal used for terminating the Signal thread.
 334 
 335 
 336 static void signal_thread_entry(JavaThread* thread, TRAPS) {
 337   os::set_priority(thread, NearMaxPriority);
 338   while (true) {
 339     int sig;
 340     {
 341       // FIXME : Currently we have not decided what should be the status
 342       //         for this java thread blocked here. Once we decide about
 343       //         that we should fix this.
 344       sig = os::signal_wait();
 345     }
 346     if (sig == os::sigexitnum_pd()) {
 347        // Terminate the signal thread
 348        return;
 349     }
 350 
 351     switch (sig) {
 352       case SIGBREAK: {
 353         // Check if the signal is a trigger to start the Attach Listener - in that
 354         // case don't print stack traces.
 355         if (!DisableAttachMechanism && AttachListener::is_init_trigger()) {
 356           continue;
 357         }
 358         // Print stack traces
 359         // Any SIGBREAK operations added here should make sure to flush
 360         // the output stream (e.g. tty->flush()) after output.  See 4803766.
 361         // Each module also prints an extra carriage return after its output.
 362         VM_PrintThreads op;
 363         VMThread::execute(&op);
 364         VM_PrintJNI jni_op;
 365         VMThread::execute(&jni_op);
 366         VM_FindDeadlocks op1(tty);
 367         VMThread::execute(&op1);
 368         Universe::print_heap_at_SIGBREAK();
 369         if (PrintClassHistogram) {
 370           VM_GC_HeapInspection op1(tty, true /* force full GC before heap inspection */);
 371           VMThread::execute(&op1);
 372         }
 373         if (JvmtiExport::should_post_data_dump()) {
 374           JvmtiExport::post_data_dump();
 375         }
 376         break;
 377       }
 378       default: {
 379         // Dispatch the signal to java
 380         HandleMark hm(THREAD);
 381         Klass* klass = SystemDictionary::resolve_or_null(vmSymbols::jdk_internal_misc_Signal(), THREAD);
 382         if (klass != NULL) {
 383           JavaValue result(T_VOID);
 384           JavaCallArguments args;
 385           args.push_int(sig);
 386           JavaCalls::call_static(
 387             &result,
 388             klass,
 389             vmSymbols::dispatch_name(),
 390             vmSymbols::int_void_signature(),
 391             &args,
 392             THREAD
 393           );
 394         }
 395         if (HAS_PENDING_EXCEPTION) {
 396           // tty is initialized early so we don't expect it to be null, but
 397           // if it is we can't risk doing an initialization that might
 398           // trigger additional out-of-memory conditions
 399           if (tty != NULL) {
 400             char klass_name[256];
 401             char tmp_sig_name[16];
 402             const char* sig_name = "UNKNOWN";
 403             InstanceKlass::cast(PENDING_EXCEPTION->klass())->
 404               name()->as_klass_external_name(klass_name, 256);
 405             if (os::exception_name(sig, tmp_sig_name, 16) != NULL)
 406               sig_name = tmp_sig_name;
 407             warning("Exception %s occurred dispatching signal %s to handler"
 408                     "- the VM may need to be forcibly terminated",
 409                     klass_name, sig_name );
 410           }
 411           CLEAR_PENDING_EXCEPTION;
 412         }
 413       }
 414     }
 415   }
 416 }
 417 
 418 void os::init_before_ergo() {
 419   initialize_initial_active_processor_count();
 420   // We need to initialize large page support here because ergonomics takes some
 421   // decisions depending on large page support and the calculated large page size.
 422   large_page_init();
 423 
 424   // We need to adapt the configured number of stack protection pages given
 425   // in 4K pages to the actual os page size. We must do this before setting
 426   // up minimal stack sizes etc. in os::init_2().
 427   JavaThread::set_stack_red_zone_size     (align_up(StackRedPages      * 4 * K, vm_page_size()));
 428   JavaThread::set_stack_yellow_zone_size  (align_up(StackYellowPages   * 4 * K, vm_page_size()));
 429   JavaThread::set_stack_reserved_zone_size(align_up(StackReservedPages * 4 * K, vm_page_size()));
 430   JavaThread::set_stack_shadow_zone_size  (align_up(StackShadowPages   * 4 * K, vm_page_size()));
 431 
 432   // VM version initialization identifies some characteristics of the
 433   // platform that are used during ergonomic decisions.
 434   VM_Version::init_before_ergo();
 435 }
 436 
 437 void os::signal_init(TRAPS) {
 438   if (!ReduceSignalUsage) {
 439     // Setup JavaThread for processing signals
 440     Klass* k = SystemDictionary::resolve_or_fail(vmSymbols::java_lang_Thread(), true, CHECK);
 441     InstanceKlass* ik = InstanceKlass::cast(k);
 442     instanceHandle thread_oop = ik->allocate_instance_handle(CHECK);
 443 
 444     const char thread_name[] = "Signal Dispatcher";
 445     Handle string = java_lang_String::create_from_str(thread_name, CHECK);
 446 
 447     // Initialize thread_oop to put it into the system threadGroup
 448     Handle thread_group (THREAD, Universe::system_thread_group());
 449     JavaValue result(T_VOID);
 450     JavaCalls::call_special(&result, thread_oop,
 451                            ik,
 452                            vmSymbols::object_initializer_name(),
 453                            vmSymbols::threadgroup_string_void_signature(),
 454                            thread_group,
 455                            string,
 456                            CHECK);
 457 
 458     Klass* group = SystemDictionary::ThreadGroup_klass();
 459     JavaCalls::call_special(&result,
 460                             thread_group,
 461                             group,
 462                             vmSymbols::add_method_name(),
 463                             vmSymbols::thread_void_signature(),
 464                             thread_oop,         // ARG 1
 465                             CHECK);
 466 
 467     os::signal_init_pd();
 468 
 469     { MutexLocker mu(Threads_lock);
 470       JavaThread* signal_thread = new JavaThread(&signal_thread_entry);
 471 
 472       // At this point it may be possible that no osthread was created for the
 473       // JavaThread due to lack of memory. We would have to throw an exception
 474       // in that case. However, since this must work and we do not allow
 475       // exceptions anyway, check and abort if this fails.
 476       if (signal_thread == NULL || signal_thread->osthread() == NULL) {
 477         vm_exit_during_initialization("java.lang.OutOfMemoryError",
 478                                       os::native_thread_creation_failed_msg());
 479       }
 480 
 481       java_lang_Thread::set_thread(thread_oop(), signal_thread);
 482       java_lang_Thread::set_priority(thread_oop(), NearMaxPriority);
 483       java_lang_Thread::set_daemon(thread_oop());
 484 
 485       signal_thread->set_threadObj(thread_oop());
 486       Threads::add(signal_thread);
 487       Thread::start(signal_thread);
 488     }
 489     // Handle ^BREAK
 490     os::signal(SIGBREAK, os::user_handler());
 491   }
 492 }
 493 
 494 
 495 void os::terminate_signal_thread() {
 496   if (!ReduceSignalUsage)
 497     signal_notify(sigexitnum_pd());
 498 }
 499 
 500 
 501 // --------------------- loading libraries ---------------------
 502 
 503 typedef jint (JNICALL *JNI_OnLoad_t)(JavaVM *, void *);
 504 extern struct JavaVM_ main_vm;
 505 
 506 static void* _native_java_library = NULL;
 507 
 508 void* os::native_java_library() {
 509   if (_native_java_library == NULL) {
 510     char buffer[JVM_MAXPATHLEN];
 511     char ebuf[1024];
 512 
 513     // Try to load verify dll first. In 1.3 java dll depends on it and is not
 514     // always able to find it when the loading executable is outside the JDK.
 515     // In order to keep working with 1.2 we ignore any loading errors.
 516     if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 517                        "verify")) {
 518       dll_load(buffer, ebuf, sizeof(ebuf));
 519     }
 520 
 521     // Load java dll
 522     if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 523                        "java")) {
 524       _native_java_library = dll_load(buffer, ebuf, sizeof(ebuf));
 525     }
 526     if (_native_java_library == NULL) {
 527       vm_exit_during_initialization("Unable to load native library", ebuf);
 528     }
 529 
 530 #if defined(__OpenBSD__)
 531     // Work-around OpenBSD's lack of $ORIGIN support by pre-loading libnet.so
 532     // ignore errors
 533     if (dll_locate_lib(buffer, sizeof(buffer), Arguments::get_dll_dir(),
 534                        "net")) {
 535       dll_load(buffer, ebuf, sizeof(ebuf));
 536     }
 537 #endif
 538   }
 539   return _native_java_library;
 540 }
 541 
 542 /*
 543  * Support for finding Agent_On(Un)Load/Attach<_lib_name> if it exists.
 544  * If check_lib == true then we are looking for an
 545  * Agent_OnLoad_lib_name or Agent_OnAttach_lib_name function to determine if
 546  * this library is statically linked into the image.
 547  * If check_lib == false then we will look for the appropriate symbol in the
 548  * executable if agent_lib->is_static_lib() == true or in the shared library
 549  * referenced by 'handle'.
 550  */
 551 void* os::find_agent_function(AgentLibrary *agent_lib, bool check_lib,
 552                               const char *syms[], size_t syms_len) {
 553   assert(agent_lib != NULL, "sanity check");
 554   const char *lib_name;
 555   void *handle = agent_lib->os_lib();
 556   void *entryName = NULL;
 557   char *agent_function_name;
 558   size_t i;
 559 
 560   // If checking then use the agent name otherwise test is_static_lib() to
 561   // see how to process this lookup
 562   lib_name = ((check_lib || agent_lib->is_static_lib()) ? agent_lib->name() : NULL);
 563   for (i = 0; i < syms_len; i++) {
 564     agent_function_name = build_agent_function_name(syms[i], lib_name, agent_lib->is_absolute_path());
 565     if (agent_function_name == NULL) {
 566       break;
 567     }
 568     entryName = dll_lookup(handle, agent_function_name);
 569     FREE_C_HEAP_ARRAY(char, agent_function_name);
 570     if (entryName != NULL) {
 571       break;
 572     }
 573   }
 574   return entryName;
 575 }
 576 
 577 // See if the passed in agent is statically linked into the VM image.
 578 bool os::find_builtin_agent(AgentLibrary *agent_lib, const char *syms[],
 579                             size_t syms_len) {
 580   void *ret;
 581   void *proc_handle;
 582   void *save_handle;
 583 
 584   assert(agent_lib != NULL, "sanity check");
 585   if (agent_lib->name() == NULL) {
 586     return false;
 587   }
 588   proc_handle = get_default_process_handle();
 589   // Check for Agent_OnLoad/Attach_lib_name function
 590   save_handle = agent_lib->os_lib();
 591   // We want to look in this process' symbol table.
 592   agent_lib->set_os_lib(proc_handle);
 593   ret = find_agent_function(agent_lib, true, syms, syms_len);
 594   if (ret != NULL) {
 595     // Found an entry point like Agent_OnLoad_lib_name so we have a static agent
 596     agent_lib->set_valid();
 597     agent_lib->set_static_lib(true);
 598     return true;
 599   }
 600   agent_lib->set_os_lib(save_handle);
 601   return false;
 602 }
 603 
 604 // --------------------- heap allocation utilities ---------------------
 605 
 606 char *os::strdup(const char *str, MEMFLAGS flags) {
 607   size_t size = strlen(str);
 608   char *dup_str = (char *)malloc(size + 1, flags);
 609   if (dup_str == NULL) return NULL;
 610   strcpy(dup_str, str);
 611   return dup_str;
 612 }
 613 
 614 char* os::strdup_check_oom(const char* str, MEMFLAGS flags) {
 615   char* p = os::strdup(str, flags);
 616   if (p == NULL) {
 617     vm_exit_out_of_memory(strlen(str) + 1, OOM_MALLOC_ERROR, "os::strdup_check_oom");
 618   }
 619   return p;
 620 }
 621 
 622 
 623 #define paranoid                 0  /* only set to 1 if you suspect checking code has bug */
 624 
 625 #ifdef ASSERT
 626 
 627 static void verify_memory(void* ptr) {
 628   GuardedMemory guarded(ptr);
 629   if (!guarded.verify_guards()) {
 630     LogTarget(Warning, malloc, free) lt;
 631     ResourceMark rm;
 632     LogStream ls(lt);
 633     ls.print_cr("## nof_mallocs = " UINT64_FORMAT ", nof_frees = " UINT64_FORMAT, os::num_mallocs, os::num_frees);
 634     ls.print_cr("## memory stomp:");
 635     guarded.print_on(&ls);
 636     fatal("memory stomping error");
 637   }
 638 }
 639 
 640 #endif
 641 
 642 //
 643 // This function supports testing of the malloc out of memory
 644 // condition without really running the system out of memory.
 645 //
 646 static bool has_reached_max_malloc_test_peak(size_t alloc_size) {
 647   if (MallocMaxTestWords > 0) {
 648     size_t words = (alloc_size / BytesPerWord);
 649 
 650     if ((cur_malloc_words + words) > MallocMaxTestWords) {
 651       return true;
 652     }
 653     Atomic::add(words, &cur_malloc_words);
 654   }
 655   return false;
 656 }
 657 
 658 void* os::malloc(size_t size, MEMFLAGS flags) {
 659   return os::malloc(size, flags, CALLER_PC);
 660 }
 661 
 662 void* os::malloc(size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 663   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 664   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 665 
 666   // Since os::malloc can be called when the libjvm.{dll,so} is
 667   // first loaded and we don't have a thread yet we must accept NULL also here.
 668   assert(!os::ThreadCrashProtection::is_crash_protected(Thread::current_or_null()),
 669          "malloc() not allowed when crash protection is set");
 670 
 671   if (size == 0) {
 672     // return a valid pointer if size is zero
 673     // if NULL is returned the calling functions assume out of memory.
 674     size = 1;
 675   }
 676 
 677   // NMT support
 678   NMT_TrackingLevel level = MemTracker::tracking_level();
 679   size_t            nmt_header_size = MemTracker::malloc_header_size(level);
 680 
 681 #ifndef ASSERT
 682   const size_t alloc_size = size + nmt_header_size;
 683 #else
 684   const size_t alloc_size = GuardedMemory::get_total_size(size + nmt_header_size);
 685   if (size + nmt_header_size > alloc_size) { // Check for rollover.
 686     return NULL;
 687   }
 688 #endif
 689 
 690   // For the test flag -XX:MallocMaxTestWords
 691   if (has_reached_max_malloc_test_peak(size)) {
 692     return NULL;
 693   }
 694 
 695   u_char* ptr;
 696   ptr = (u_char*)::malloc(alloc_size);
 697 
 698 #ifdef ASSERT
 699   if (ptr == NULL) {
 700     return NULL;
 701   }
 702   // Wrap memory with guard
 703   GuardedMemory guarded(ptr, size + nmt_header_size);
 704   ptr = guarded.get_user_ptr();
 705 #endif
 706   if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 707     log_warning(malloc, free)("os::malloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 708     breakpoint();
 709   }
 710   debug_only(if (paranoid) verify_memory(ptr));
 711 
 712   // we do not track guard memory
 713   return MemTracker::record_malloc((address)ptr, size, memflags, stack, level);
 714 }
 715 
 716 void* os::realloc(void *memblock, size_t size, MEMFLAGS flags) {
 717   return os::realloc(memblock, size, flags, CALLER_PC);
 718 }
 719 
 720 void* os::realloc(void *memblock, size_t size, MEMFLAGS memflags, const NativeCallStack& stack) {
 721 
 722   // For the test flag -XX:MallocMaxTestWords
 723   if (has_reached_max_malloc_test_peak(size)) {
 724     return NULL;
 725   }
 726 
 727   if (size == 0) {
 728     // return a valid pointer if size is zero
 729     // if NULL is returned the calling functions assume out of memory.
 730     size = 1;
 731   }
 732 
 733 #ifndef ASSERT
 734   NOT_PRODUCT(inc_stat_counter(&num_mallocs, 1));
 735   NOT_PRODUCT(inc_stat_counter(&alloc_bytes, size));
 736    // NMT support
 737   void* membase = MemTracker::record_free(memblock);
 738   NMT_TrackingLevel level = MemTracker::tracking_level();
 739   size_t  nmt_header_size = MemTracker::malloc_header_size(level);
 740   void* ptr = ::realloc(membase, size + nmt_header_size);
 741   return MemTracker::record_malloc(ptr, size, memflags, stack, level);
 742 #else
 743   if (memblock == NULL) {
 744     return os::malloc(size, memflags, stack);
 745   }
 746   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 747     log_warning(malloc, free)("os::realloc caught " PTR_FORMAT, p2i(memblock));
 748     breakpoint();
 749   }
 750   // NMT support
 751   void* membase = MemTracker::malloc_base(memblock);
 752   verify_memory(membase);
 753   // always move the block
 754   void* ptr = os::malloc(size, memflags, stack);
 755   // Copy to new memory if malloc didn't fail
 756   if (ptr != NULL ) {
 757     GuardedMemory guarded(MemTracker::malloc_base(memblock));
 758     // Guard's user data contains NMT header
 759     size_t memblock_size = guarded.get_user_size() - MemTracker::malloc_header_size(memblock);
 760     memcpy(ptr, memblock, MIN2(size, memblock_size));
 761     if (paranoid) verify_memory(MemTracker::malloc_base(ptr));
 762     if ((intptr_t)ptr == (intptr_t)MallocCatchPtr) {
 763       log_warning(malloc, free)("os::realloc caught, " SIZE_FORMAT " bytes --> " PTR_FORMAT, size, p2i(ptr));
 764       breakpoint();
 765     }
 766     os::free(memblock);
 767   }
 768   return ptr;
 769 #endif
 770 }
 771 
 772 
 773 void  os::free(void *memblock) {
 774   NOT_PRODUCT(inc_stat_counter(&num_frees, 1));
 775 #ifdef ASSERT
 776   if (memblock == NULL) return;
 777   if ((intptr_t)memblock == (intptr_t)MallocCatchPtr) {
 778     log_warning(malloc, free)("os::free caught " PTR_FORMAT, p2i(memblock));
 779     breakpoint();
 780   }
 781   void* membase = MemTracker::record_free(memblock);
 782   verify_memory(membase);
 783 
 784   GuardedMemory guarded(membase);
 785   size_t size = guarded.get_user_size();
 786   inc_stat_counter(&free_bytes, size);
 787   membase = guarded.release_for_freeing();
 788   ::free(membase);
 789 #else
 790   void* membase = MemTracker::record_free(memblock);
 791   ::free(membase);
 792 #endif
 793 }
 794 
 795 void os::init_random(unsigned int initval) {
 796   _rand_seed = initval;
 797 }
 798 
 799 
 800 static int random_helper(unsigned int rand_seed) {
 801   /* standard, well-known linear congruential random generator with
 802    * next_rand = (16807*seed) mod (2**31-1)
 803    * see
 804    * (1) "Random Number Generators: Good Ones Are Hard to Find",
 805    *      S.K. Park and K.W. Miller, Communications of the ACM 31:10 (Oct 1988),
 806    * (2) "Two Fast Implementations of the 'Minimal Standard' Random
 807    *     Number Generator", David G. Carta, Comm. ACM 33, 1 (Jan 1990), pp. 87-88.
 808   */
 809   const unsigned int a = 16807;
 810   const unsigned int m = 2147483647;
 811   const int q = m / a;        assert(q == 127773, "weird math");
 812   const int r = m % a;        assert(r == 2836, "weird math");
 813 
 814   // compute az=2^31p+q
 815   unsigned int lo = a * (rand_seed & 0xFFFF);
 816   unsigned int hi = a * (rand_seed >> 16);
 817   lo += (hi & 0x7FFF) << 16;
 818 
 819   // if q overflowed, ignore the overflow and increment q
 820   if (lo > m) {
 821     lo &= m;
 822     ++lo;
 823   }
 824   lo += hi >> 15;
 825 
 826   // if (p+q) overflowed, ignore the overflow and increment (p+q)
 827   if (lo > m) {
 828     lo &= m;
 829     ++lo;
 830   }
 831   return lo;
 832 }
 833 
 834 int os::random() {
 835   // Make updating the random seed thread safe.
 836   while (true) {
 837     unsigned int seed = _rand_seed;
 838     unsigned int rand = random_helper(seed);
 839     if (Atomic::cmpxchg(rand, &_rand_seed, seed) == seed) {
 840       return static_cast<int>(rand);
 841     }
 842   }
 843 }
 844 
 845 // The INITIALIZED state is distinguished from the SUSPENDED state because the
 846 // conditions in which a thread is first started are different from those in which
 847 // a suspension is resumed.  These differences make it hard for us to apply the
 848 // tougher checks when starting threads that we want to do when resuming them.
 849 // However, when start_thread is called as a result of Thread.start, on a Java
 850 // thread, the operation is synchronized on the Java Thread object.  So there
 851 // cannot be a race to start the thread and hence for the thread to exit while
 852 // we are working on it.  Non-Java threads that start Java threads either have
 853 // to do so in a context in which races are impossible, or should do appropriate
 854 // locking.
 855 
 856 void os::start_thread(Thread* thread) {
 857   // guard suspend/resume
 858   MutexLockerEx ml(thread->SR_lock(), Mutex::_no_safepoint_check_flag);
 859   OSThread* osthread = thread->osthread();
 860   osthread->set_state(RUNNABLE);
 861   pd_start_thread(thread);
 862 }
 863 
 864 void os::abort(bool dump_core) {
 865   abort(dump_core && CreateCoredumpOnCrash, NULL, NULL);
 866 }
 867 
 868 //---------------------------------------------------------------------------
 869 // Helper functions for fatal error handler
 870 
 871 void os::print_hex_dump(outputStream* st, address start, address end, int unitsize) {
 872   assert(unitsize == 1 || unitsize == 2 || unitsize == 4 || unitsize == 8, "just checking");
 873 
 874   int cols = 0;
 875   int cols_per_line = 0;
 876   switch (unitsize) {
 877     case 1: cols_per_line = 16; break;
 878     case 2: cols_per_line = 8;  break;
 879     case 4: cols_per_line = 4;  break;
 880     case 8: cols_per_line = 2;  break;
 881     default: return;
 882   }
 883 
 884   address p = start;
 885   st->print(PTR_FORMAT ":   ", p2i(start));
 886   while (p < end) {
 887     switch (unitsize) {
 888       case 1: st->print("%02x", *(u1*)p); break;
 889       case 2: st->print("%04x", *(u2*)p); break;
 890       case 4: st->print("%08x", *(u4*)p); break;
 891       case 8: st->print("%016" FORMAT64_MODIFIER "x", *(u8*)p); break;
 892     }
 893     p += unitsize;
 894     cols++;
 895     if (cols >= cols_per_line && p < end) {
 896        cols = 0;
 897        st->cr();
 898        st->print(PTR_FORMAT ":   ", p2i(p));
 899     } else {
 900        st->print(" ");
 901     }
 902   }
 903   st->cr();
 904 }
 905 
 906 void os::print_environment_variables(outputStream* st, const char** env_list) {
 907   if (env_list) {
 908     st->print_cr("Environment Variables:");
 909 
 910     for (int i = 0; env_list[i] != NULL; i++) {
 911       char *envvar = ::getenv(env_list[i]);
 912       if (envvar != NULL) {
 913         st->print("%s", env_list[i]);
 914         st->print("=");
 915         st->print_cr("%s", envvar);
 916       }
 917     }
 918   }
 919 }
 920 
 921 void os::print_cpu_info(outputStream* st, char* buf, size_t buflen) {
 922   // cpu
 923   st->print("CPU:");
 924   st->print("total %d", os::processor_count());
 925   // It's not safe to query number of active processors after crash
 926   // st->print("(active %d)", os::active_processor_count()); but we can
 927   // print the initial number of active processors.
 928   // We access the raw value here because the assert in the accessor will
 929   // fail if the crash occurs before initialization of this value.
 930   st->print(" (initial active %d)", _initial_active_processor_count);
 931   st->print(" %s", VM_Version::features_string());
 932   st->cr();
 933   pd_print_cpu_info(st, buf, buflen);
 934 }
 935 
 936 // Print a one line string summarizing the cpu, number of cores, memory, and operating system version
 937 void os::print_summary_info(outputStream* st, char* buf, size_t buflen) {
 938   st->print("Host: ");
 939 #ifndef PRODUCT
 940   if (get_host_name(buf, buflen)) {
 941     st->print("%s, ", buf);
 942   }
 943 #endif // PRODUCT
 944   get_summary_cpu_info(buf, buflen);
 945   st->print("%s, ", buf);
 946   size_t mem = physical_memory()/G;
 947   if (mem == 0) {  // for low memory systems
 948     mem = physical_memory()/M;
 949     st->print("%d cores, " SIZE_FORMAT "M, ", processor_count(), mem);
 950   } else {
 951     st->print("%d cores, " SIZE_FORMAT "G, ", processor_count(), mem);
 952   }
 953   get_summary_os_info(buf, buflen);
 954   st->print_raw(buf);
 955   st->cr();
 956 }
 957 
 958 void os::print_date_and_time(outputStream *st, char* buf, size_t buflen) {
 959   const int secs_per_day  = 86400;
 960   const int secs_per_hour = 3600;
 961   const int secs_per_min  = 60;
 962 
 963   time_t tloc;
 964   (void)time(&tloc);
 965   char* timestring = ctime(&tloc);  // ctime adds newline.
 966   // edit out the newline
 967   char* nl = strchr(timestring, '\n');
 968   if (nl != NULL) {
 969     *nl = '\0';
 970   }
 971 
 972   struct tm tz;
 973   if (localtime_pd(&tloc, &tz) != NULL) {
 974     ::strftime(buf, buflen, "%Z", &tz);
 975     st->print("Time: %s %s", timestring, buf);
 976   } else {
 977     st->print("Time: %s", timestring);
 978   }
 979 
 980   double t = os::elapsedTime();
 981   // NOTE: It tends to crash after a SEGV if we want to printf("%f",...) in
 982   //       Linux. Must be a bug in glibc ? Workaround is to round "t" to int
 983   //       before printf. We lost some precision, but who cares?
 984   int eltime = (int)t;  // elapsed time in seconds
 985 
 986   // print elapsed time in a human-readable format:
 987   int eldays = eltime / secs_per_day;
 988   int day_secs = eldays * secs_per_day;
 989   int elhours = (eltime - day_secs) / secs_per_hour;
 990   int hour_secs = elhours * secs_per_hour;
 991   int elmins = (eltime - day_secs - hour_secs) / secs_per_min;
 992   int minute_secs = elmins * secs_per_min;
 993   int elsecs = (eltime - day_secs - hour_secs - minute_secs);
 994   st->print_cr(" elapsed time: %d seconds (%dd %dh %dm %ds)", eltime, eldays, elhours, elmins, elsecs);
 995 }
 996 
 997 // moved from debug.cpp (used to be find()) but still called from there
 998 // The verbose parameter is only set by the debug code in one case
 999 void os::print_location(outputStream* st, intptr_t x, bool verbose) {
1000   address addr = (address)x;
1001   // Handle NULL first, so later checks don't need to protect against it.
1002   if (addr == NULL) {
1003     st->print_cr("0x0 is NULL");
1004     return;
1005   }
1006   CodeBlob* b = CodeCache::find_blob_unsafe(addr);
1007   if (b != NULL) {
1008     if (b->is_buffer_blob()) {
1009       // the interpreter is generated into a buffer blob
1010       InterpreterCodelet* i = Interpreter::codelet_containing(addr);
1011       if (i != NULL) {
1012         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an Interpreter codelet", p2i(addr), (int)(addr - i->code_begin()));
1013         i->print_on(st);
1014         return;
1015       }
1016       if (Interpreter::contains(addr)) {
1017         st->print_cr(INTPTR_FORMAT " is pointing into interpreter code"
1018                      " (not bytecode specific)", p2i(addr));
1019         return;
1020       }
1021       //
1022       if (AdapterHandlerLibrary::contains(b)) {
1023         st->print_cr(INTPTR_FORMAT " is at code_begin+%d in an AdapterHandler", p2i(addr), (int)(addr - b->code_begin()));
1024         AdapterHandlerLibrary::print_handler_on(st, b);
1025       }
1026       // the stubroutines are generated into a buffer blob
1027       StubCodeDesc* d = StubCodeDesc::desc_for(addr);
1028       if (d != NULL) {
1029         st->print_cr(INTPTR_FORMAT " is at begin+%d in a stub", p2i(addr), (int)(addr - d->begin()));
1030         d->print_on(st);
1031         st->cr();
1032         return;
1033       }
1034       if (StubRoutines::contains(addr)) {
1035         st->print_cr(INTPTR_FORMAT " is pointing to an (unnamed) stub routine", p2i(addr));
1036         return;
1037       }
1038       // the InlineCacheBuffer is using stubs generated into a buffer blob
1039       if (InlineCacheBuffer::contains(addr)) {
1040         st->print_cr(INTPTR_FORMAT " is pointing into InlineCacheBuffer", p2i(addr));
1041         return;
1042       }
1043       VtableStub* v = VtableStubs::stub_containing(addr);
1044       if (v != NULL) {
1045         st->print_cr(INTPTR_FORMAT " is at entry_point+%d in a vtable stub", p2i(addr), (int)(addr - v->entry_point()));
1046         v->print_on(st);
1047         st->cr();
1048         return;
1049       }
1050     }
1051     nmethod* nm = b->as_nmethod_or_null();
1052     if (nm != NULL) {
1053       ResourceMark rm;
1054       st->print(INTPTR_FORMAT " is at entry_point+%d in (nmethod*)" INTPTR_FORMAT,
1055                 p2i(addr), (int)(addr - nm->entry_point()), p2i(nm));
1056       if (verbose) {
1057         st->print(" for ");
1058         nm->method()->print_value_on(st);
1059       }
1060       st->cr();
1061       nm->print_nmethod(verbose);
1062       return;
1063     }
1064     st->print_cr(INTPTR_FORMAT " is at code_begin+%d in ", p2i(addr), (int)(addr - b->code_begin()));
1065     b->print_on(st);
1066     return;
1067   }
1068 
1069   if (Universe::heap()->is_in(addr)) {
1070     HeapWord* p = Universe::heap()->block_start(addr);
1071     bool print = false;
1072     // If we couldn't find it it just may mean that heap wasn't parsable
1073     // See if we were just given an oop directly
1074     if (p != NULL && Universe::heap()->block_is_obj(p)) {
1075       print = true;
1076     } else if (p == NULL && oopDesc::is_oop(oop(addr))) {
1077       p = (HeapWord*) addr;
1078       print = true;
1079     }
1080     if (print) {
1081       if (p == (HeapWord*) addr) {
1082         st->print_cr(INTPTR_FORMAT " is an oop", p2i(addr));
1083       } else {
1084         st->print_cr(INTPTR_FORMAT " is pointing into object: " INTPTR_FORMAT, p2i(addr), p2i(p));
1085       }
1086       oop(p)->print_on(st);
1087       return;
1088     }
1089   } else {
1090     if (Universe::heap()->is_in_reserved(addr)) {
1091       st->print_cr(INTPTR_FORMAT " is an unallocated location "
1092                    "in the heap", p2i(addr));
1093       return;
1094     }
1095   }
1096   if (JNIHandles::is_global_handle((jobject) addr)) {
1097     st->print_cr(INTPTR_FORMAT " is a global jni handle", p2i(addr));
1098     return;
1099   }
1100   if (JNIHandles::is_weak_global_handle((jobject) addr)) {
1101     st->print_cr(INTPTR_FORMAT " is a weak global jni handle", p2i(addr));
1102     return;
1103   }
1104 #ifndef PRODUCT
1105   // we don't keep the block list in product mode
1106   if (JNIHandles::is_local_handle((jobject) addr)) {
1107     st->print_cr(INTPTR_FORMAT " is a local jni handle", p2i(addr));
1108     return;
1109   }
1110 #endif
1111 
1112   for (JavaThreadIteratorWithHandle jtiwh; JavaThread *thread = jtiwh.next(); ) {
1113     // Check for privilege stack
1114     if (thread->privileged_stack_top() != NULL &&
1115         thread->privileged_stack_top()->contains(addr)) {
1116       st->print_cr(INTPTR_FORMAT " is pointing into the privilege stack "
1117                    "for thread: " INTPTR_FORMAT, p2i(addr), p2i(thread));
1118       if (verbose) thread->print_on(st);
1119       return;
1120     }
1121     // If the addr is a java thread print information about that.
1122     if (addr == (address)thread) {
1123       if (verbose) {
1124         thread->print_on(st);
1125       } else {
1126         st->print_cr(INTPTR_FORMAT " is a thread", p2i(addr));
1127       }
1128       return;
1129     }
1130     // If the addr is in the stack region for this thread then report that
1131     // and print thread info
1132     if (thread->on_local_stack(addr)) {
1133       st->print_cr(INTPTR_FORMAT " is pointing into the stack for thread: "
1134                    INTPTR_FORMAT, p2i(addr), p2i(thread));
1135       if (verbose) thread->print_on(st);
1136       return;
1137     }
1138   }
1139 
1140   // Check if in metaspace and print types that have vptrs (only method now)
1141   if (Metaspace::contains(addr)) {
1142     if (Method::has_method_vptr((const void*)addr)) {
1143       ((Method*)addr)->print_value_on(st);
1144       st->cr();
1145     } else {
1146       // Use addr->print() from the debugger instead (not here)
1147       st->print_cr(INTPTR_FORMAT " is pointing into metadata", p2i(addr));
1148     }
1149     return;
1150   }
1151 
1152   // Try an OS specific find
1153   if (os::find(addr, st)) {
1154     return;
1155   }
1156 
1157   st->print_cr(INTPTR_FORMAT " is an unknown value", p2i(addr));
1158 }
1159 
1160 // Looks like all platforms except IA64 can use the same function to check
1161 // if C stack is walkable beyond current frame. The check for fp() is not
1162 // necessary on Sparc, but it's harmless.
1163 bool os::is_first_C_frame(frame* fr) {
1164 #if (defined(IA64) && !defined(AIX)) && !defined(_WIN32)
1165   // On IA64 we have to check if the callers bsp is still valid
1166   // (i.e. within the register stack bounds).
1167   // Notice: this only works for threads created by the VM and only if
1168   // we walk the current stack!!! If we want to be able to walk
1169   // arbitrary other threads, we'll have to somehow store the thread
1170   // object in the frame.
1171   Thread *thread = Thread::current();
1172   if ((address)fr->fp() <=
1173       thread->register_stack_base() HPUX_ONLY(+ 0x0) LINUX_ONLY(+ 0x50)) {
1174     // This check is a little hacky, because on Linux the first C
1175     // frame's ('start_thread') register stack frame starts at
1176     // "register_stack_base + 0x48" while on HPUX, the first C frame's
1177     // ('__pthread_bound_body') register stack frame seems to really
1178     // start at "register_stack_base".
1179     return true;
1180   } else {
1181     return false;
1182   }
1183 #elif defined(IA64) && defined(_WIN32)
1184   return true;
1185 #else
1186   // Load up sp, fp, sender sp and sender fp, check for reasonable values.
1187   // Check usp first, because if that's bad the other accessors may fault
1188   // on some architectures.  Ditto ufp second, etc.
1189   uintptr_t fp_align_mask = (uintptr_t)(sizeof(address)-1);
1190   // sp on amd can be 32 bit aligned.
1191   uintptr_t sp_align_mask = (uintptr_t)(sizeof(int)-1);
1192 
1193   uintptr_t usp    = (uintptr_t)fr->sp();
1194   if ((usp & sp_align_mask) != 0) return true;
1195 
1196   uintptr_t ufp    = (uintptr_t)fr->fp();
1197   if ((ufp & fp_align_mask) != 0) return true;
1198 
1199   uintptr_t old_sp = (uintptr_t)fr->sender_sp();
1200   if ((old_sp & sp_align_mask) != 0) return true;
1201   if (old_sp == 0 || old_sp == (uintptr_t)-1) return true;
1202 
1203   uintptr_t old_fp = (uintptr_t)fr->link();
1204   if ((old_fp & fp_align_mask) != 0) return true;
1205   if (old_fp == 0 || old_fp == (uintptr_t)-1 || old_fp == ufp) return true;
1206 
1207   // stack grows downwards; if old_fp is below current fp or if the stack
1208   // frame is too large, either the stack is corrupted or fp is not saved
1209   // on stack (i.e. on x86, ebp may be used as general register). The stack
1210   // is not walkable beyond current frame.
1211   if (old_fp < ufp) return true;
1212   if (old_fp - ufp > 64 * K) return true;
1213 
1214   return false;
1215 #endif
1216 }
1217 
1218 
1219 // Set up the boot classpath.
1220 
1221 char* os::format_boot_path(const char* format_string,
1222                            const char* home,
1223                            int home_len,
1224                            char fileSep,
1225                            char pathSep) {
1226     assert((fileSep == '/' && pathSep == ':') ||
1227            (fileSep == '\\' && pathSep == ';'), "unexpected separator chars");
1228 
1229     // Scan the format string to determine the length of the actual
1230     // boot classpath, and handle platform dependencies as well.
1231     int formatted_path_len = 0;
1232     const char* p;
1233     for (p = format_string; *p != 0; ++p) {
1234         if (*p == '%') formatted_path_len += home_len - 1;
1235         ++formatted_path_len;
1236     }
1237 
1238     char* formatted_path = NEW_C_HEAP_ARRAY(char, formatted_path_len + 1, mtInternal);
1239     if (formatted_path == NULL) {
1240         return NULL;
1241     }
1242 
1243     // Create boot classpath from format, substituting separator chars and
1244     // java home directory.
1245     char* q = formatted_path;
1246     for (p = format_string; *p != 0; ++p) {
1247         switch (*p) {
1248         case '%':
1249             strcpy(q, home);
1250             q += home_len;
1251             break;
1252         case '/':
1253             *q++ = fileSep;
1254             break;
1255         case ':':
1256             *q++ = pathSep;
1257             break;
1258         default:
1259             *q++ = *p;
1260         }
1261     }
1262     *q = '\0';
1263 
1264     assert((q - formatted_path) == formatted_path_len, "formatted_path size botched");
1265     return formatted_path;
1266 }
1267 
1268 bool os::set_boot_path(char fileSep, char pathSep) {
1269   const char* home = Arguments::get_java_home();
1270   int home_len = (int)strlen(home);
1271 
1272   struct stat st;
1273 
1274   // modular image if "modules" jimage exists
1275   char* jimage = format_boot_path("%/lib/" MODULES_IMAGE_NAME, home, home_len, fileSep, pathSep);
1276   if (jimage == NULL) return false;
1277   bool has_jimage = (os::stat(jimage, &st) == 0);
1278   if (has_jimage) {
1279     Arguments::set_sysclasspath(jimage, true);
1280     FREE_C_HEAP_ARRAY(char, jimage);
1281     return true;
1282   }
1283   FREE_C_HEAP_ARRAY(char, jimage);
1284 
1285   // check if developer build with exploded modules
1286   char* base_classes = format_boot_path("%/modules/" JAVA_BASE_NAME, home, home_len, fileSep, pathSep);
1287   if (base_classes == NULL) return false;
1288   if (os::stat(base_classes, &st) == 0) {
1289     Arguments::set_sysclasspath(base_classes, false);
1290     FREE_C_HEAP_ARRAY(char, base_classes);
1291     return true;
1292   }
1293   FREE_C_HEAP_ARRAY(char, base_classes);
1294 
1295   return false;
1296 }
1297 
1298 /*
1299  * Splits a path, based on its separator, the number of
1300  * elements is returned back in n.
1301  * It is the callers responsibility to:
1302  *   a> check the value of n, and n may be 0.
1303  *   b> ignore any empty path elements
1304  *   c> free up the data.
1305  */
1306 char** os::split_path(const char* path, int* n) {
1307   *n = 0;
1308   if (path == NULL || strlen(path) == 0) {
1309     return NULL;
1310   }
1311   const char psepchar = *os::path_separator();
1312   char* inpath = (char*)NEW_C_HEAP_ARRAY(char, strlen(path) + 1, mtInternal);
1313   if (inpath == NULL) {
1314     return NULL;
1315   }
1316   strcpy(inpath, path);
1317   int count = 1;
1318   char* p = strchr(inpath, psepchar);
1319   // Get a count of elements to allocate memory
1320   while (p != NULL) {
1321     count++;
1322     p++;
1323     p = strchr(p, psepchar);
1324   }
1325   char** opath = (char**) NEW_C_HEAP_ARRAY(char*, count, mtInternal);
1326   if (opath == NULL) {
1327     return NULL;
1328   }
1329 
1330   // do the actual splitting
1331   p = inpath;
1332   for (int i = 0 ; i < count ; i++) {
1333     size_t len = strcspn(p, os::path_separator());
1334     if (len > JVM_MAXPATHLEN) {
1335       return NULL;
1336     }
1337     // allocate the string and add terminator storage
1338     char* s  = (char*)NEW_C_HEAP_ARRAY(char, len + 1, mtInternal);
1339     if (s == NULL) {
1340       return NULL;
1341     }
1342     strncpy(s, p, len);
1343     s[len] = '\0';
1344     opath[i] = s;
1345     p += len + 1;
1346   }
1347   FREE_C_HEAP_ARRAY(char, inpath);
1348   *n = count;
1349   return opath;
1350 }
1351 
1352 void os::set_memory_serialize_page(address page) {
1353   int count = log2_intptr(sizeof(class JavaThread)) - log2_intptr(64);
1354   _mem_serialize_page = (volatile int32_t *)page;
1355   // We initialize the serialization page shift count here
1356   // We assume a cache line size of 64 bytes
1357   assert(SerializePageShiftCount == count, "JavaThread size changed; "
1358          "SerializePageShiftCount constant should be %d", count);
1359   set_serialize_page_mask((uintptr_t)(vm_page_size() - sizeof(int32_t)));
1360 }
1361 
1362 static volatile intptr_t SerializePageLock = 0;
1363 
1364 // This method is called from signal handler when SIGSEGV occurs while the current
1365 // thread tries to store to the "read-only" memory serialize page during state
1366 // transition.
1367 void os::block_on_serialize_page_trap() {
1368   log_debug(safepoint)("Block until the serialize page permission restored");
1369 
1370   // When VMThread is holding the SerializePageLock during modifying the
1371   // access permission of the memory serialize page, the following call
1372   // will block until the permission of that page is restored to rw.
1373   // Generally, it is unsafe to manipulate locks in signal handlers, but in
1374   // this case, it's OK as the signal is synchronous and we know precisely when
1375   // it can occur.
1376   Thread::muxAcquire(&SerializePageLock, "set_memory_serialize_page");
1377   Thread::muxRelease(&SerializePageLock);
1378 }
1379 
1380 // Serialize all thread state variables
1381 void os::serialize_thread_states() {
1382   // On some platforms such as Solaris & Linux, the time duration of the page
1383   // permission restoration is observed to be much longer than expected  due to
1384   // scheduler starvation problem etc. To avoid the long synchronization
1385   // time and expensive page trap spinning, 'SerializePageLock' is used to block
1386   // the mutator thread if such case is encountered. See bug 6546278 for details.
1387   Thread::muxAcquire(&SerializePageLock, "serialize_thread_states");
1388   os::protect_memory((char *)os::get_memory_serialize_page(),
1389                      os::vm_page_size(), MEM_PROT_READ);
1390   os::protect_memory((char *)os::get_memory_serialize_page(),
1391                      os::vm_page_size(), MEM_PROT_RW);
1392   Thread::muxRelease(&SerializePageLock);
1393 }
1394 
1395 // Returns true if the current stack pointer is above the stack shadow
1396 // pages, false otherwise.
1397 bool os::stack_shadow_pages_available(Thread *thread, const methodHandle& method, address sp) {
1398   if (!thread->is_Java_thread()) return false;
1399   // Check if we have StackShadowPages above the yellow zone.  This parameter
1400   // is dependent on the depth of the maximum VM call stack possible from
1401   // the handler for stack overflow.  'instanceof' in the stack overflow
1402   // handler or a println uses at least 8k stack of VM and native code
1403   // respectively.
1404   const int framesize_in_bytes =
1405     Interpreter::size_top_interpreter_activation(method()) * wordSize;
1406 
1407   address limit = ((JavaThread*)thread)->stack_end() +
1408                   (JavaThread::stack_guard_zone_size() + JavaThread::stack_shadow_zone_size());
1409 
1410   return sp > (limit + framesize_in_bytes);
1411 }
1412 
1413 size_t os::page_size_for_region(size_t region_size, size_t min_pages, bool must_be_aligned) {
1414   assert(min_pages > 0, "sanity");
1415   if (UseLargePages) {
1416     const size_t max_page_size = region_size / min_pages;
1417 
1418     for (size_t i = 0; _page_sizes[i] != 0; ++i) {
1419       const size_t page_size = _page_sizes[i];
1420       if (page_size <= max_page_size) {
1421         if (!must_be_aligned || is_aligned(region_size, page_size)) {
1422           return page_size;
1423         }
1424       }
1425     }
1426   }
1427 
1428   return vm_page_size();
1429 }
1430 
1431 size_t os::page_size_for_region_aligned(size_t region_size, size_t min_pages) {
1432   return page_size_for_region(region_size, min_pages, true);
1433 }
1434 
1435 size_t os::page_size_for_region_unaligned(size_t region_size, size_t min_pages) {
1436   return page_size_for_region(region_size, min_pages, false);
1437 }
1438 
1439 static const char* errno_to_string (int e, bool short_text) {
1440   #define ALL_SHARED_ENUMS(X) \
1441     X(E2BIG, "Argument list too long") \
1442     X(EACCES, "Permission denied") \
1443     X(EADDRINUSE, "Address in use") \
1444     X(EADDRNOTAVAIL, "Address not available") \
1445     X(EAFNOSUPPORT, "Address family not supported") \
1446     X(EAGAIN, "Resource unavailable, try again") \
1447     X(EALREADY, "Connection already in progress") \
1448     X(EBADF, "Bad file descriptor") \
1449     X(EBADMSG, "Bad message") \
1450     X(EBUSY, "Device or resource busy") \
1451     X(ECANCELED, "Operation canceled") \
1452     X(ECHILD, "No child processes") \
1453     X(ECONNABORTED, "Connection aborted") \
1454     X(ECONNREFUSED, "Connection refused") \
1455     X(ECONNRESET, "Connection reset") \
1456     X(EDEADLK, "Resource deadlock would occur") \
1457     X(EDESTADDRREQ, "Destination address required") \
1458     X(EDOM, "Mathematics argument out of domain of function") \
1459     X(EEXIST, "File exists") \
1460     X(EFAULT, "Bad address") \
1461     X(EFBIG, "File too large") \
1462     X(EHOSTUNREACH, "Host is unreachable") \
1463     X(EIDRM, "Identifier removed") \
1464     X(EILSEQ, "Illegal byte sequence") \
1465     X(EINPROGRESS, "Operation in progress") \
1466     X(EINTR, "Interrupted function") \
1467     X(EINVAL, "Invalid argument") \
1468     X(EIO, "I/O error") \
1469     X(EISCONN, "Socket is connected") \
1470     X(EISDIR, "Is a directory") \
1471     X(ELOOP, "Too many levels of symbolic links") \
1472     X(EMFILE, "Too many open files") \
1473     X(EMLINK, "Too many links") \
1474     X(EMSGSIZE, "Message too large") \
1475     X(ENAMETOOLONG, "Filename too long") \
1476     X(ENETDOWN, "Network is down") \
1477     X(ENETRESET, "Connection aborted by network") \
1478     X(ENETUNREACH, "Network unreachable") \
1479     X(ENFILE, "Too many files open in system") \
1480     X(ENOBUFS, "No buffer space available") \
1481     X(ENODATA, "No message is available on the STREAM head read queue") \
1482     X(ENODEV, "No such device") \
1483     X(ENOENT, "No such file or directory") \
1484     X(ENOEXEC, "Executable file format error") \
1485     X(ENOLCK, "No locks available") \
1486     X(ENOLINK, "Reserved") \
1487     X(ENOMEM, "Not enough space") \
1488     X(ENOMSG, "No message of the desired type") \
1489     X(ENOPROTOOPT, "Protocol not available") \
1490     X(ENOSPC, "No space left on device") \
1491     X(ENOSR, "No STREAM resources") \
1492     X(ENOSTR, "Not a STREAM") \
1493     X(ENOSYS, "Function not supported") \
1494     X(ENOTCONN, "The socket is not connected") \
1495     X(ENOTDIR, "Not a directory") \
1496     X(ENOTEMPTY, "Directory not empty") \
1497     X(ENOTSOCK, "Not a socket") \
1498     X(ENOTSUP, "Not supported") \
1499     X(ENOTTY, "Inappropriate I/O control operation") \
1500     X(ENXIO, "No such device or address") \
1501     X(EOPNOTSUPP, "Operation not supported on socket") \
1502     X(EOVERFLOW, "Value too large to be stored in data type") \
1503     X(EPERM, "Operation not permitted") \
1504     X(EPIPE, "Broken pipe") \
1505     X(EPROTO, "Protocol error") \
1506     X(EPROTONOSUPPORT, "Protocol not supported") \
1507     X(EPROTOTYPE, "Protocol wrong type for socket") \
1508     X(ERANGE, "Result too large") \
1509     X(EROFS, "Read-only file system") \
1510     X(ESPIPE, "Invalid seek") \
1511     X(ESRCH, "No such process") \
1512     X(ETIME, "Stream ioctl() timeout") \
1513     X(ETIMEDOUT, "Connection timed out") \
1514     X(ETXTBSY, "Text file busy") \
1515     X(EWOULDBLOCK, "Operation would block") \
1516     X(EXDEV, "Cross-device link")
1517 
1518   #define DEFINE_ENTRY(e, text) { e, #e, text },
1519 
1520   static const struct {
1521     int v;
1522     const char* short_text;
1523     const char* long_text;
1524   } table [] = {
1525 
1526     ALL_SHARED_ENUMS(DEFINE_ENTRY)
1527 
1528     // The following enums are not defined on all platforms.
1529     #ifdef ESTALE
1530     DEFINE_ENTRY(ESTALE, "Reserved")
1531     #endif
1532     #ifdef EDQUOT
1533     DEFINE_ENTRY(EDQUOT, "Reserved")
1534     #endif
1535     #ifdef EMULTIHOP
1536     DEFINE_ENTRY(EMULTIHOP, "Reserved")
1537     #endif
1538 
1539     // End marker.
1540     { -1, "Unknown errno", "Unknown error" }
1541 
1542   };
1543 
1544   #undef DEFINE_ENTRY
1545   #undef ALL_FLAGS
1546 
1547   int i = 0;
1548   while (table[i].v != -1 && table[i].v != e) {
1549     i ++;
1550   }
1551 
1552   return short_text ? table[i].short_text : table[i].long_text;
1553 
1554 }
1555 
1556 const char* os::strerror(int e) {
1557   return errno_to_string(e, false);
1558 }
1559 
1560 const char* os::errno_name(int e) {
1561   return errno_to_string(e, true);
1562 }
1563 
1564 void os::trace_page_sizes(const char* str, const size_t* page_sizes, int count) {
1565   LogTarget(Info, pagesize) log;
1566   if (log.is_enabled()) {
1567     LogStream out(log);
1568 
1569     out.print("%s: ", str);
1570     for (int i = 0; i < count; ++i) {
1571       out.print(" " SIZE_FORMAT, page_sizes[i]);
1572     }
1573     out.cr();
1574   }
1575 }
1576 
1577 #define trace_page_size_params(size) byte_size_in_exact_unit(size), exact_unit_for_byte_size(size)
1578 
1579 void os::trace_page_sizes(const char* str,
1580                           const size_t region_min_size,
1581                           const size_t region_max_size,
1582                           const size_t page_size,
1583                           const char* base,
1584                           const size_t size) {
1585 
1586   log_info(pagesize)("%s: "
1587                      " min=" SIZE_FORMAT "%s"
1588                      " max=" SIZE_FORMAT "%s"
1589                      " base=" PTR_FORMAT
1590                      " page_size=" SIZE_FORMAT "%s"
1591                      " size=" SIZE_FORMAT "%s",
1592                      str,
1593                      trace_page_size_params(region_min_size),
1594                      trace_page_size_params(region_max_size),
1595                      p2i(base),
1596                      trace_page_size_params(page_size),
1597                      trace_page_size_params(size));
1598 }
1599 
1600 void os::trace_page_sizes_for_requested_size(const char* str,
1601                                              const size_t requested_size,
1602                                              const size_t page_size,
1603                                              const size_t alignment,
1604                                              const char* base,
1605                                              const size_t size) {
1606 
1607   log_info(pagesize)("%s:"
1608                      " req_size=" SIZE_FORMAT "%s"
1609                      " base=" PTR_FORMAT
1610                      " page_size=" SIZE_FORMAT "%s"
1611                      " alignment=" SIZE_FORMAT "%s"
1612                      " size=" SIZE_FORMAT "%s",
1613                      str,
1614                      trace_page_size_params(requested_size),
1615                      p2i(base),
1616                      trace_page_size_params(page_size),
1617                      trace_page_size_params(alignment),
1618                      trace_page_size_params(size));
1619 }
1620 
1621 
1622 // This is the working definition of a server class machine:
1623 // >= 2 physical CPU's and >=2GB of memory, with some fuzz
1624 // because the graphics memory (?) sometimes masks physical memory.
1625 // If you want to change the definition of a server class machine
1626 // on some OS or platform, e.g., >=4GB on Windows platforms,
1627 // then you'll have to parameterize this method based on that state,
1628 // as was done for logical processors here, or replicate and
1629 // specialize this method for each platform.  (Or fix os to have
1630 // some inheritance structure and use subclassing.  Sigh.)
1631 // If you want some platform to always or never behave as a server
1632 // class machine, change the setting of AlwaysActAsServerClassMachine
1633 // and NeverActAsServerClassMachine in globals*.hpp.
1634 bool os::is_server_class_machine() {
1635   // First check for the early returns
1636   if (NeverActAsServerClassMachine) {
1637     return false;
1638   }
1639   if (AlwaysActAsServerClassMachine) {
1640     return true;
1641   }
1642   // Then actually look at the machine
1643   bool         result            = false;
1644   const unsigned int    server_processors = 2;
1645   const julong server_memory     = 2UL * G;
1646   // We seem not to get our full complement of memory.
1647   //     We allow some part (1/8?) of the memory to be "missing",
1648   //     based on the sizes of DIMMs, and maybe graphics cards.
1649   const julong missing_memory   = 256UL * M;
1650 
1651   /* Is this a server class machine? */
1652   if ((os::active_processor_count() >= (int)server_processors) &&
1653       (os::physical_memory() >= (server_memory - missing_memory))) {
1654     const unsigned int logical_processors =
1655       VM_Version::logical_processors_per_package();
1656     if (logical_processors > 1) {
1657       const unsigned int physical_packages =
1658         os::active_processor_count() / logical_processors;
1659       if (physical_packages >= server_processors) {
1660         result = true;
1661       }
1662     } else {
1663       result = true;
1664     }
1665   }
1666   return result;
1667 }
1668 
1669 void os::initialize_initial_active_processor_count() {
1670   assert(_initial_active_processor_count == 0, "Initial active processor count already set.");
1671   _initial_active_processor_count = active_processor_count();
1672   log_debug(os)("Initial active processor count set to %d" , _initial_active_processor_count);
1673 }
1674 
1675 void os::SuspendedThreadTask::run() {
1676   internal_do_task();
1677   _done = true;
1678 }
1679 
1680 bool os::create_stack_guard_pages(char* addr, size_t bytes) {
1681   return os::pd_create_stack_guard_pages(addr, bytes);
1682 }
1683 
1684 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint, int file_desc) {
1685   char* result = NULL;
1686 
1687   if (file_desc != -1) {
1688     // Could have called pd_reserve_memory() followed by replace_existing_mapping_with_file_mapping(),
1689     // but AIX may use SHM in which case its more trouble to detach the segment and remap memory to the file.
1690     result = os::map_memory_to_file(addr, bytes, file_desc);
1691     if (result != NULL) {
1692       MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1693     }
1694   } else {
1695     result = pd_reserve_memory(bytes, addr, alignment_hint);
1696     if (result != NULL) {
1697       MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1698     }
1699   }
1700 
1701   return result;
1702 }
1703 
1704 char* os::reserve_memory(size_t bytes, char* addr, size_t alignment_hint,
1705    MEMFLAGS flags) {
1706   char* result = pd_reserve_memory(bytes, addr, alignment_hint);
1707   if (result != NULL) {
1708     MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1709     MemTracker::record_virtual_memory_type((address)result, flags);
1710   }
1711 
1712   return result;
1713 }
1714 
1715 char* os::attempt_reserve_memory_at(size_t bytes, char* addr, int file_desc) {
1716   char* result = NULL;
1717   if (file_desc != -1) {
1718     result = pd_attempt_reserve_memory_at(bytes, addr, file_desc);
1719     if (result != NULL) {
1720       MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1721     }
1722   } else {
1723     result = pd_attempt_reserve_memory_at(bytes, addr);
1724     if (result != NULL) {
1725       MemTracker::record_virtual_memory_reserve((address)result, bytes, CALLER_PC);
1726     }
1727   }
1728   return result;
1729 }
1730 
1731 void os::split_reserved_memory(char *base, size_t size,
1732                                  size_t split, bool realloc) {
1733   pd_split_reserved_memory(base, size, split, realloc);
1734 }
1735 
1736 bool os::commit_memory(char* addr, size_t bytes, bool executable) {
1737   bool res = pd_commit_memory(addr, bytes, executable);
1738   if (res) {
1739     MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1740   }
1741   return res;
1742 }
1743 
1744 bool os::commit_memory(char* addr, size_t size, size_t alignment_hint,
1745                               bool executable) {
1746   bool res = os::pd_commit_memory(addr, size, alignment_hint, executable);
1747   if (res) {
1748     MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1749   }
1750   return res;
1751 }
1752 
1753 void os::commit_memory_or_exit(char* addr, size_t bytes, bool executable,
1754                                const char* mesg) {
1755   pd_commit_memory_or_exit(addr, bytes, executable, mesg);
1756   MemTracker::record_virtual_memory_commit((address)addr, bytes, CALLER_PC);
1757 }
1758 
1759 void os::commit_memory_or_exit(char* addr, size_t size, size_t alignment_hint,
1760                                bool executable, const char* mesg) {
1761   os::pd_commit_memory_or_exit(addr, size, alignment_hint, executable, mesg);
1762   MemTracker::record_virtual_memory_commit((address)addr, size, CALLER_PC);
1763 }
1764 
1765 bool os::uncommit_memory(char* addr, size_t bytes) {
1766   bool res;
1767   if (MemTracker::tracking_level() > NMT_minimal) {
1768     Tracker tkr(Tracker::uncommit);
1769     res = pd_uncommit_memory(addr, bytes);
1770     if (res) {
1771       tkr.record((address)addr, bytes);
1772     }
1773   } else {
1774     res = pd_uncommit_memory(addr, bytes);
1775   }
1776   return res;
1777 }
1778 
1779 bool os::release_memory(char* addr, size_t bytes) {
1780   bool res;
1781   if (MemTracker::tracking_level() > NMT_minimal) {
1782     Tracker tkr(Tracker::release);
1783     res = pd_release_memory(addr, bytes);
1784     if (res) {
1785       tkr.record((address)addr, bytes);
1786     }
1787   } else {
1788     res = pd_release_memory(addr, bytes);
1789   }
1790   return res;
1791 }
1792 
1793 void os::pretouch_memory(void* start, void* end, size_t page_size) {
1794   for (volatile char *p = (char*)start; p < (char*)end; p += page_size) {
1795     *p = 0;
1796   }
1797 }
1798 
1799 char* os::map_memory(int fd, const char* file_name, size_t file_offset,
1800                            char *addr, size_t bytes, bool read_only,
1801                            bool allow_exec) {
1802   char* result = pd_map_memory(fd, file_name, file_offset, addr, bytes, read_only, allow_exec);
1803   if (result != NULL) {
1804     MemTracker::record_virtual_memory_reserve_and_commit((address)result, bytes, CALLER_PC);
1805   }
1806   return result;
1807 }
1808 
1809 char* os::remap_memory(int fd, const char* file_name, size_t file_offset,
1810                              char *addr, size_t bytes, bool read_only,
1811                              bool allow_exec) {
1812   return pd_remap_memory(fd, file_name, file_offset, addr, bytes,
1813                     read_only, allow_exec);
1814 }
1815 
1816 bool os::unmap_memory(char *addr, size_t bytes) {
1817   bool result;
1818   if (MemTracker::tracking_level() > NMT_minimal) {
1819     Tracker tkr(Tracker::release);
1820     result = pd_unmap_memory(addr, bytes);
1821     if (result) {
1822       tkr.record((address)addr, bytes);
1823     }
1824   } else {
1825     result = pd_unmap_memory(addr, bytes);
1826   }
1827   return result;
1828 }
1829 
1830 void os::free_memory(char *addr, size_t bytes, size_t alignment_hint) {
1831   pd_free_memory(addr, bytes, alignment_hint);
1832 }
1833 
1834 void os::realign_memory(char *addr, size_t bytes, size_t alignment_hint) {
1835   pd_realign_memory(addr, bytes, alignment_hint);
1836 }
1837 
1838 #ifndef _WINDOWS
1839 /* try to switch state from state "from" to state "to"
1840  * returns the state set after the method is complete
1841  */
1842 os::SuspendResume::State os::SuspendResume::switch_state(os::SuspendResume::State from,
1843                                                          os::SuspendResume::State to)
1844 {
1845   os::SuspendResume::State result = Atomic::cmpxchg(to, &_state, from);
1846   if (result == from) {
1847     // success
1848     return to;
1849   }
1850   return result;
1851 }
1852 #endif