text: /*
   * Copyright (c) 2016 Advanced Micro Devices, Inc.
   * Copyright (c) 2003-2005 The Regents of The University of Michigan
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted provided that the following conditions are
   * met: redistributions of source code must retain the above copyright
   * notice, this list of conditions and the following disclaimer;
   * redistributions in binary form must reproduce the above copyright
   * notice, this list of conditions and the following disclaimer in the
   * documentation and/or other materials provided with the distribution;
   * neither the name of the copyright holders nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #include "sim/syscall_desc.hh"
  
  #include "base/types.hh"
  #include "sim/eventq.hh"
  #include "sim/syscall_debug_macros.hh"
  
  namespace gem5
  {
  
  class ThreadContext;
  
  void
  SyscallDesc::doSyscall(ThreadContext *tc)
  {
      DPRINTF_SYSCALL(Base, "Calling %s...\n", dumper(name(), tc));
  
      SyscallReturn retval = executor(this, tc);
  
      if (retval.needsRetry()) {
          // Suspend this ThreadContext while the syscall is pending.
          tc->suspend();
  
          DPRINTF_SYSCALL(Base, "%s needs retry.\n", name());
          setupRetry(tc);
          return;
      }
  
      handleReturn(tc, retval);
  }
  
  void
  SyscallDesc::retrySyscall(ThreadContext *tc)
  {
      DPRINTF_SYSCALL(Base, "Retrying %s...\n", dumper(name(), tc));
  
      SyscallReturn retval = executor(this, tc);
  
      if (retval.needsRetry()) {
          DPRINTF_SYSCALL(Base, "%s still needs retry.\n", name());
          setupRetry(tc);
          return;
      }
  
      // We're done retrying, so reactivate this ThreadContext.
      tc->activate();
  
      handleReturn(tc, retval);
  }
  
  void
  SyscallDesc::setupRetry(ThreadContext *tc)
  {
      // Create an event which will retry the system call later.
      auto retry = [this, tc]() { retrySyscall(tc); };
      auto *event = new EventFunctionWrapper(retry, name(), true);
  
      // Schedule it in about 100 CPU cycles. That will give other contexts
      // a chance to execute a bit of code before trying again.
      auto *cpu = tc->getCpuPtr();
      curEventQueue()->schedule(event,
              curTick() + cpu->cyclesToTicks(Cycles(100)));
  }
  
  void
  SyscallDesc::handleReturn(ThreadContext *tc, const SyscallReturn &ret)
  {
      if (ret.suppressed()) {
          DPRINTF_SYSCALL(Base, "No return value.\n", name());
      } else {
          returnInto(tc, ret);
          DPRINTF_SYSCALL(Base, "Returned %d.\n", ret.encodedValue());
      }
  }
  
  } // namespace gem5
  