syscall-emul: Adds SE mode signal feature

This changeset adds a simple class definition and a member
in the System object to track signals sent between processes.
The implementation cannot support all signals that might be
sent between processes, but it can support some of the simple
use cases like SIGCHLD.

Change-Id: Id5f95aa60e7f49da1c5b5596fbfa26e729453ac7
Reviewed-on: https://gem5-review.googlesource.com/2267
Reviewed-by: Michael LeBeane <Michael.Lebeane@amd.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>

src/sim/SConscript

@@ -66,6 +66,7 @@ Source('stat_control.cc')
 Source('stat_register.cc', skip_no_python=True)
 Source('clock_domain.cc')
 Source('voltage_domain.cc')
+Source('se_signal.cc')
 Source('linear_solver.cc')
 Source('system.cc')
 Source('dvfs_handler.cc')

src/sim/se_signal.cc

@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2017 Advanced Micro Devices, Inc.
+ * 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.
+ *
+ * Author: Brandon Potter
+ */
+
+#include "sim/se_signal.hh"
+
+BasicSignal::BasicSignal(Process *send, Process *receive, int signal_val)
+    : sender(send),
+      receiver(receive),
+      signalValue(signal_val)
+{
+}
+
+
+BasicSignal::~BasicSignal()
+{
+}

src/sim/se_signal.hh

@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2017 Advanced Micro Devices, Inc.
+ * 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.
+ *
+ * Author: Brandon Potter
+ */
+
+#ifndef __SE_SIGNAL_HH__
+#define __SE_SIGNAL_HH__
+
+class Process;
+
+class BasicSignal {
+  public:
+    Process *sender;
+    Process *receiver;
+    int signalValue;
+
+    BasicSignal(Process *sender, Process *receiver, int signal_val);
+    ~BasicSignal();
+};
+
+#endif // __SE_SIGNAL_HH__

src/sim/system.hh

@@ -61,6 +61,7 @@
 #include "mem/port_proxy.hh"
 #include "mem/physical.hh"
 #include "params/System.hh"
+#include "sim/se_signal.hh"
 
 /**
  * To avoid linking errors with LTO, only include the header if we
@@ -556,6 +557,10 @@ class System : public MemObject
     /** Process set to track which PIDs have already been allocated */
     std::set<int> PIDs;
 
+    // By convention, all signals are owned by the receiving process. The
+    // receiver will delete the signal upon reception.
+    std::list<BasicSignal> signalList;
+
   protected:
 
     /**