/*

 * Copyright (c) 1997, 2019, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 *

 */

#include "precompiled.hpp"

#include "memory/universe.hpp"

#include "runtime/mutexLocker.hpp"

#include "runtime/os.inline.hpp"

#include "runtime/safepoint.hpp"

#include "runtime/thread.inline.hpp"

#include "runtime/vmThread.hpp"

// Mutexes used in the VM (see comment in mutexLocker.hpp):

//

// Note that the following pointers are effectively final -- after having been

// set at JVM startup-time, they should never be subsequently mutated.

// Instead of using pointers to malloc()ed monitors and mutexes we should consider

// eliminating the indirection and using instances instead.

// Consider using GCC's __read_mostly.

Mutex*   Patching_lock                = NULL;

Monitor* SystemDictionary_lock        = NULL;

Mutex*   ProtectionDomainSet_lock     = NULL;

Mutex*   SharedDictionary_lock        = NULL;

Mutex*   Module_lock                  = NULL;

Mutex*   CompiledIC_lock              = NULL;

Mutex*   InlineCacheBuffer_lock       = NULL;

Mutex*   VMStatistic_lock             = NULL;

Mutex*   JNIGlobalAlloc_lock          = NULL;

Mutex*   JNIGlobalActive_lock         = NULL;

Mutex*   JNIWeakAlloc_lock            = NULL;

Mutex*   JNIWeakActive_lock           = NULL;

Mutex*   StringTableWeakAlloc_lock    = NULL;

Mutex*   StringTableWeakActive_lock   = NULL;

Mutex*   JNIHandleBlockFreeList_lock  = NULL;

Mutex*   VMWeakAlloc_lock             = NULL;

Mutex*   VMWeakActive_lock            = NULL;

Mutex*   ResolvedMethodTableWeakAlloc_lock  = NULL;

Mutex*   ResolvedMethodTableWeakActive_lock = NULL;

Mutex*   JmethodIdCreation_lock       = NULL;

Mutex*   JfieldIdCreation_lock        = NULL;

Monitor* JNICritical_lock             = NULL;

Mutex*   JvmtiThreadState_lock        = NULL;

Monitor* Heap_lock                    = NULL;

Mutex*   ExpandHeap_lock              = NULL;

Mutex*   AdapterHandlerLibrary_lock   = NULL;

Mutex*   SignatureHandlerLibrary_lock = NULL;

Mutex*   VtableStubs_lock             = NULL;

Mutex*   SymbolArena_lock             = NULL;

Monitor* StringDedupQueue_lock        = NULL;

Mutex*   StringDedupTable_lock        = NULL;

Monitor* CodeCache_lock               = NULL;

Mutex*   MethodData_lock              = NULL;

Mutex*   TouchedMethodLog_lock        = NULL;

Mutex*   RetData_lock                 = NULL;

Monitor* VMOperationQueue_lock        = NULL;

Monitor* VMOperationRequest_lock      = NULL;

Monitor* SerializePage_lock           = NULL;

Monitor* Threads_lock                 = NULL;

Mutex*   NonJavaThreadsList_lock      = NULL;

Mutex*   NonJavaThreadsListSync_lock  = NULL;

Monitor* CGC_lock                     = NULL;

Monitor* STS_lock                     = NULL;

Monitor* FullGCCount_lock             = NULL;

Monitor* DirtyCardQ_CBL_mon           = NULL;

Mutex*   Shared_DirtyCardQ_lock       = NULL;

Mutex*   MarkStackFreeList_lock       = NULL;

Mutex*   MarkStackChunkList_lock      = NULL;

Mutex*   MonitoringSupport_lock       = NULL;

Mutex*   ParGCRareEvent_lock          = NULL;

Monitor* CGCPhaseManager_lock         = NULL;

Mutex*   Compile_lock                 = NULL;

Monitor* MethodCompileQueue_lock      = NULL;

Monitor* CompileThread_lock           = NULL;

Monitor* Compilation_lock             = NULL;

Mutex*   CompileTaskAlloc_lock        = NULL;

Mutex*   CompileStatistics_lock       = NULL;

Mutex*   DirectivesStack_lock         = NULL;

Mutex*   MultiArray_lock              = NULL;

Monitor* Terminator_lock              = NULL;

Monitor* InitCompleted_lock           = NULL;

Monitor* BeforeExit_lock              = NULL;

Monitor* Notify_lock                  = NULL;

Mutex*   ProfilePrint_lock            = NULL;

Mutex*   ExceptionCache_lock          = NULL;

Mutex*   OsrList_lock                 = NULL;

Mutex*   NMethodSweeperStats_lock     = NULL;

#ifndef PRODUCT

Mutex*   FullGCALot_lock              = NULL;

#endif

Mutex*   Debug1_lock                  = NULL;

Mutex*   Debug2_lock                  = NULL;

Mutex*   Debug3_lock                  = NULL;

Mutex*   tty_lock                     = NULL;

Mutex*   RawMonitor_lock              = NULL;

Mutex*   PerfDataMemAlloc_lock        = NULL;

Mutex*   PerfDataManager_lock         = NULL;

Mutex*   OopMapCacheAlloc_lock        = NULL;

Mutex*   FreeList_lock                = NULL;

Mutex*   OldSets_lock                 = NULL;

Monitor* RootRegionScan_lock          = NULL;

Monitor* GCTaskManager_lock           = NULL;

Mutex*   Management_lock              = NULL;

Monitor* Service_lock                 = NULL;

Monitor* PeriodicTask_lock            = NULL;

Monitor* RedefineClasses_lock         = NULL;

#if INCLUDE_JFR

Mutex*   JfrStacktrace_lock           = NULL;

Monitor* JfrMsg_lock                  = NULL;

Mutex*   JfrBuffer_lock               = NULL;

Mutex*   JfrStream_lock               = NULL;

Monitor* JfrThreadSampler_lock        = NULL;

#endif

#ifndef SUPPORTS_NATIVE_CX8

Mutex*   UnsafeJlong_lock             = NULL;

#endif

Monitor* CodeHeapStateAnalytics_lock  = NULL;

Mutex*   MetaspaceExpand_lock         = NULL;

Mutex*   ClassLoaderDataGraph_lock    = NULL;

Monitor* ThreadsSMRDelete_lock        = NULL;

Mutex*   SharedDecoder_lock           = NULL;

Mutex*   DCmdFactory_lock             = NULL;

#if INCLUDE_NMT

Mutex*   NMTQuery_lock                = NULL;

#endif

#if INCLUDE_CDS

#if INCLUDE_JVMTI

Mutex*   CDSClassFileStream_lock      = NULL;

#endif

Mutex*   DumpTimeTable_lock           = NULL;

#endif // INCLUDE_CDS

#if INCLUDE_JVMCI

Monitor* JVMCI_lock                   = NULL;

Mutex*   JVMCIGlobalAlloc_lock        = NULL;

Mutex*   JVMCIGlobalActive_lock       = NULL;

#endif

#define MAX_NUM_MUTEX 128

static Monitor * _mutex_array[MAX_NUM_MUTEX];

static int _num_mutex;

#ifdef ASSERT

void assert_locked_or_safepoint(const Monitor * lock) {

  // check if this thread owns the lock (common case)

  if (IgnoreLockingAssertions) return;

  assert(lock != NULL, "Need non-NULL lock");

  if (lock->owned_by_self()) return;

  if (SafepointSynchronize::is_at_safepoint()) return;

  if (!Universe::is_fully_initialized()) return;

  // see if invoker of VM operation owns it

  VM_Operation* op = VMThread::vm_operation();

  if (op != NULL && op->calling_thread() == lock->owner()) return;

  fatal("must own lock %s", lock->name());

}

// a weaker assertion than the above

void assert_locked_or_safepoint_weak(const Monitor * lock) {

  if (IgnoreLockingAssertions) return;

  assert(lock != NULL, "Need non-NULL lock");

  if (lock->is_locked()) return;

  if (SafepointSynchronize::is_at_safepoint()) return;

  if (!Universe::is_fully_initialized()) return;

  fatal("must own lock %s", lock->name());

}

// a stronger assertion than the above

void assert_lock_strong(const Monitor * lock) {

  if (IgnoreLockingAssertions) return;

  assert(lock != NULL, "Need non-NULL lock");

  if (lock->owned_by_self()) return;

  fatal("must own lock %s", lock->name());

}

#endif

#define def(var, type, pri, vm_block, safepoint_check_allowed ) {      \

  var = new type(Mutex::pri, #var, vm_block, safepoint_check_allowed); \

  assert(_num_mutex < MAX_NUM_MUTEX, "increase MAX_NUM_MUTEX");        \

  _mutex_array[_num_mutex++] = var;                                      \

}

// Using Padded subclasses to prevent false sharing of these global monitors and mutexes.

void mutex_init() {

  def(tty_lock                     , PaddedMutex  , tty,         true,  Monitor::_safepoint_check_never);      // allow to lock in VM

  def(CGC_lock                     , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // coordinate between fore- and background GC

  def(STS_lock                     , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);

  def(VMWeakAlloc_lock             , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);

  def(VMWeakActive_lock            , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);

  def(StringTableWeakAlloc_lock    , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);

  def(StringTableWeakActive_lock   , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);

  def(ResolvedMethodTableWeakAlloc_lock    , PaddedMutex  , vmweak,      true,  Monitor::_safepoint_check_never);

  def(ResolvedMethodTableWeakActive_lock   , PaddedMutex  , vmweak-1,    true,  Monitor::_safepoint_check_never);

  def(FullGCCount_lock             , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);      // in support of ExplicitGCInvokesConcurrent

  if (UseG1GC) {

    def(DirtyCardQ_CBL_mon         , PaddedMonitor, access,      true,  Monitor::_safepoint_check_never);

    def(Shared_DirtyCardQ_lock     , PaddedMutex  , access + 1,  true,  Monitor::_safepoint_check_never);

    def(FreeList_lock              , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);

    def(OldSets_lock               , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);

    def(RootRegionScan_lock        , PaddedMonitor, leaf     ,   true,  Monitor::_safepoint_check_never);

    def(StringDedupQueue_lock      , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);

    def(StringDedupTable_lock      , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

    def(MarkStackFreeList_lock     , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);

    def(MarkStackChunkList_lock    , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_never);

    def(MonitoringSupport_lock     , PaddedMutex  , native   ,   true,  Monitor::_safepoint_check_never);      // used for serviceability monitoring support

  }

  if (UseShenandoahGC) {

    def(StringDedupQueue_lock      , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);

    def(StringDedupTable_lock      , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

  }

  def(ParGCRareEvent_lock          , PaddedMutex  , leaf     ,   true,  Monitor::_safepoint_check_always);

  def(CGCPhaseManager_lock         , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_always);

  def(CodeCache_lock               , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);

  def(RawMonitor_lock              , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);

  def(OopMapCacheAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for oop_map_cache allocation.

  def(MetaspaceExpand_lock         , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);

  def(ClassLoaderDataGraph_lock    , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);

  def(Patching_lock                , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);      // used for safepointing and code patching.

  def(Service_lock                 , PaddedMonitor, special,     true,  Monitor::_safepoint_check_never);      // used for service thread operations

  def(JmethodIdCreation_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for creating jmethodIDs.

  def(SystemDictionary_lock        , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);

  def(ProtectionDomainSet_lock     , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);

  def(SharedDictionary_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always);

  def(Module_lock                  , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_always);

  def(InlineCacheBuffer_lock       , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

  def(VMStatistic_lock             , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);

  def(ExpandHeap_lock              , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // Used during compilation by VM thread

  def(JNIHandleBlockFreeList_lock  , PaddedMutex  , leaf-1,      true,  Monitor::_safepoint_check_never);      // handles are used by VM thread

  def(SignatureHandlerLibrary_lock , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always);

  def(SymbolArena_lock             , PaddedMutex  , leaf+2,      true,  Monitor::_safepoint_check_never);

  def(ProfilePrint_lock            , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always); // serial profile printing

  def(ExceptionCache_lock          , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always); // serial profile printing

  def(OsrList_lock                 , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

  def(Debug1_lock                  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

#ifndef PRODUCT

  def(FullGCALot_lock              , PaddedMutex  , leaf,        false, Monitor::_safepoint_check_always); // a lock to make FullGCALot MT safe

#endif

  def(BeforeExit_lock              , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);

  def(PerfDataMemAlloc_lock        , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for allocating PerfData memory for performance data

  def(PerfDataManager_lock         , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_always); // used for synchronized access to PerfDataManager resources

  // CMS_modUnionTable_lock                   leaf

  // CMS_bitMap_lock                          leaf 1

  // CMS_freeList_lock                        leaf 2

  def(Threads_lock                 , PaddedMonitor, barrier,     true,  Monitor::_safepoint_check_sometimes);  // Used for safepoint protocol.

  def(NonJavaThreadsList_lock      , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_never);

  def(NonJavaThreadsListSync_lock  , PaddedMutex,   leaf,        true,  Monitor::_safepoint_check_never);

  def(VMOperationQueue_lock        , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_never);  // VM_thread allowed to block on these

  def(VMOperationRequest_lock      , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);

  def(RetData_lock                 , PaddedMutex  , nonleaf,     false, Monitor::_safepoint_check_always);

  def(Terminator_lock              , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);

  def(InitCompleted_lock           , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);

  def(VtableStubs_lock             , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);

  def(Notify_lock                  , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always);

  def(JNIGlobalAlloc_lock          , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);

  def(JNIGlobalActive_lock         , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);

  def(JNIWeakAlloc_lock            , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);

  def(JNIWeakActive_lock           , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);

  def(JNICritical_lock             , PaddedMonitor, nonleaf,     true,  Monitor::_safepoint_check_always); // used for JNI critical regions

  def(AdapterHandlerLibrary_lock   , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_always);

  def(Heap_lock                    , PaddedMonitor, nonleaf+1,   false, Monitor::_safepoint_check_sometimes);  // Doesn't safepoint check during termination.

  def(JfieldIdCreation_lock        , PaddedMutex  , nonleaf+1,   true,  Monitor::_safepoint_check_always); // jfieldID, Used in VM_Operation

  def(CompiledIC_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_never);      // locks VtableStubs_lock, InlineCacheBuffer_lock

  def(CompileTaskAlloc_lock        , PaddedMutex  , nonleaf+2,   true,  Monitor::_safepoint_check_always);

  def(CompileStatistics_lock       , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);

  def(DirectivesStack_lock         , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);

  def(MultiArray_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always);

  def(JvmtiThreadState_lock        , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always); // Used by JvmtiThreadState/JvmtiEventController

  def(Management_lock              , PaddedMutex  , nonleaf+2,   false, Monitor::_safepoint_check_always); // used for JVM management

  def(Compile_lock                 , PaddedMutex  , nonleaf+3,   true,  Monitor::_safepoint_check_always);

  def(MethodData_lock              , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);

  def(TouchedMethodLog_lock        , PaddedMutex  , nonleaf+3,   false, Monitor::_safepoint_check_always);

  def(MethodCompileQueue_lock      , PaddedMonitor, nonleaf+4,   true,  Monitor::_safepoint_check_always);

  def(Debug2_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);

  def(Debug3_lock                  , PaddedMutex  , nonleaf+4,   true,  Monitor::_safepoint_check_never);

  def(CompileThread_lock           , PaddedMonitor, nonleaf+5,   false, Monitor::_safepoint_check_always);

  def(PeriodicTask_lock            , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);

  def(RedefineClasses_lock         , PaddedMonitor, nonleaf+5,   true,  Monitor::_safepoint_check_always);

  if (WhiteBoxAPI) {

    def(Compilation_lock           , PaddedMonitor, leaf,        false, Monitor::_safepoint_check_never);

  }

#if INCLUDE_JFR

  def(JfrMsg_lock                  , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_always);

  def(JfrBuffer_lock               , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

  def(JfrStream_lock               , PaddedMutex  , leaf+1,      true,  Monitor::_safepoint_check_never);      // ensure to rank lower than 'safepoint'

  def(JfrStacktrace_lock           , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);

  def(JfrThreadSampler_lock        , PaddedMonitor, leaf,        true,  Monitor::_safepoint_check_never);

#endif

#ifndef SUPPORTS_NATIVE_CX8

  def(UnsafeJlong_lock             , PaddedMutex  , special,     false, Monitor::_safepoint_check_never);

#endif

  def(CodeHeapStateAnalytics_lock  , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

  def(NMethodSweeperStats_lock     , PaddedMutex  , special,     true,  Monitor::_safepoint_check_never);

  def(ThreadsSMRDelete_lock        , PaddedMonitor, special,     false, Monitor::_safepoint_check_never);

  def(SharedDecoder_lock           , PaddedMutex  , native,      false, Monitor::_safepoint_check_never);

  def(DCmdFactory_lock             , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

#if INCLUDE_NMT

  def(NMTQuery_lock                , PaddedMutex  , max_nonleaf, false, Monitor::_safepoint_check_always);

#endif

#if INCLUDE_CDS

#if INCLUDE_JVMTI

  def(CDSClassFileStream_lock      , PaddedMutex  , max_nonleaf, false, Monitor::_safepoint_check_always);

#endif

#if INCLUDE_JVMCI

  def(JVMCI_lock                   , PaddedMonitor, nonleaf+2,   true,  Monitor::_safepoint_check_always);

  def(JVMCIGlobalAlloc_lock        , PaddedMutex  , nonleaf,     true,  Monitor::_safepoint_check_never);

  def(JVMCIGlobalActive_lock       , PaddedMutex  , nonleaf-1,   true,  Monitor::_safepoint_check_never);

#endif

  def(DumpTimeTable_lock           , PaddedMutex  , leaf,        true,  Monitor::_safepoint_check_never);

#endif // INCLUDE_CDS

}

GCMutexLocker::GCMutexLocker(Monitor * mutex) {

  if (SafepointSynchronize::is_at_safepoint()) {

    _locked = false;

  } else {

    _mutex = mutex;

    _locked = true;

    _mutex->lock();

  }

}

// Print all mutexes/monitors that are currently owned by a thread; called

// by fatal error handler.

void print_owned_locks_on_error(outputStream* st) {

  st->print("VM Mutex/Monitor currently owned by a thread: ");

  bool none = true;

  for (int i = 0; i < _num_mutex; i++) {

     // see if it has an owner

     if (_mutex_array[i]->owner() != NULL) {

       if (none) {

          // print format used by Mutex::print_on_error()

          st->print_cr(" ([mutex/lock_event])");

          none = false;

       }

       _mutex_array[i]->print_on_error(st);

       st->cr();

     }

  }

  if (none) st->print_cr("None");

}