1  /*
 2   * Copyright (C) 2017 Apple Inc. All rights reserved.
 3   *
 4   * Redistribution and use in source and binary forms, with or without
 5   * modification, are permitted provided that the following conditions
 6   * are met:
 7   * 1. Redistributions of source code must retain the above copyright
 8   *    notice, this list of conditions and the following disclaimer.
 9   * 2. Redistributions in binary form must reproduce the above copyright
10   *    notice, this list of conditions and the following disclaimer in the
11   *    documentation and/or other materials provided with the distribution.
12   *
13   * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14   * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15   * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16   * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
17   * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18   * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19   * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20   * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21   * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24   */
25  
26  #include "config.h"
27  #include "WasmMachineThreads.h"
28  
29  #if ENABLE(WEBASSEMBLY)
30  
31  #include "MachineStackMarker.h"
32  #include <wtf/NeverDestroyed.h>
33  #include <wtf/ThreadMessage.h>
34  
35  namespace JSC { namespace Wasm {
36  
37  
38  inline MachineThreads& wasmThreads()
39  {
40      static LazyNeverDestroyed<MachineThreads> threads;
41      static std::once_flag once;
42      std::call_once(once, [] {
43          threads.construct();
44      });
45  
46      return threads;
47  }
48  
49  void startTrackingCurrentThread()
50  {
51      wasmThreads().addCurrentThread();
52  }
53  
54  void resetInstructionCacheOnAllThreads()
55  {
56      auto locker = holdLock(wasmThreads().getLock());
57      for (auto& thread : wasmThreads().threads(locker)) {
58          sendMessage(thread.get(), [] (const PlatformRegisters&) {
59              // It's likely that the signal handler will already reset the instruction cache but we might as well be sure.
60              WTF::crossModifyingCodeFence();
61          });
62      }
63  }
64  
65      
66  } } // namespace JSC::Wasm
67  
68  #endif // ENABLE(WEBASSEMBLY)