sim: SystemC hosting

This patch hosts gem5 onto SystemC scheduler. There's already an upstream
review board patch that does something similar but this patch ...:

 1) is less obtrusive to the existing gem5 code organisation. It's divided
 into the 'generic' preparatory patches (already submitted) and this patch
 which affects no existing files

 2) does not try to exactly track the gem5 event queue with notifys into
 SystemC and so doesn't requive the event queue to be modified for
 anything other than 'out of event queue' scheduling events

 3) supports debug logging with SC_REPORT

The patch consists of the files:
    util/systemc/
        sc_gem5_control.{cc,hh} -- top level objects to use to
                                   instantiate gem5 Systems within
                                   larger SystemC test harnesses as
                                   sc_module objects
        sc_logger.{cc,hh}       -- logging support
        sc_module.{cc,hh}       -- a separated event loop specific to
                                   SystemC
        stats.{cc,hh}           -- example Stats handling for the sample
                                   top level
        main.{cc,hh}            -- a sample top level

On the downside this patch is only currently functional with C++
configuration at the top level.

The above sc_... files are indended to be compiled alongside gem5 (as a
library, see main.cc for a command line and util/systemc/README for
more details.)

The top-level system instantiation in sc_gem5_control.{cc,hh} provides
two classes: Gem5Control and Gem5System

Gem5Control is a simulation control class (from which a singleton
object should be created) derived from Gem5SystemC::Module which
carries the top level simulation control interface for gem5.  This
includes hosting a system-building configuration file and
instantiating the Root object from that file.

Gem5System is a base class for instantiating renamed gem5 Systems
from the config file hosted by the Gem5Control object.  In use, a
SystemC module class should be made which represents the desired,
instantiable gem5 System.  That class's instances should create
a Gem5System during their construction, set the parameters of that
system and then call instantiate to build that system.  If this
is all carried out in the sc_core::sc_module-derived classes
constructor, the System's external ports will become children of
that module and can then be recovered by name using sc_core::
sc_find_object.

It is intended that this interface is used with dlopen.  To that
end, the header file sc_gem5_control.hh includes no other header
files from gem5 (and so can be easily copied into another project).
The classes Gem5System and Gem5Control have all their member
functions declared `virtual' so that those functions can be called
through the vtable acquired by building the top level Gem5Control
using dlsym(..., "makeGem5Control") and `makeSystem' on the
Gem5Control.

1 files changed, 248 insertions, 0 deletions

diff --git a/util/systemc/sc_gem5_control.cc b/util/systemc/sc_gem5_control.cc
new file mode 100644
index 000000000..09a1be995
--- /dev/null
+++ b/util/systemc/sc_gem5_control.cc
@@ -0,0 +1,248 @@
+/*
+ * Copyright (c) 2014 ARM Limited
+ * All rights reserved
+ *
+ * The license below extends only to copyright in the software and shall
+ * not be construed as granting a license to any other intellectual
+ * property including but not limited to intellectual property relating
+ * to a hardware implementation of the functionality of the software
+ * licensed hereunder.  You may use the software subject to the license
+ * terms below provided that you ensure that this notice is replicated
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
+ * 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.
+ *
+ * Authors: Andrew Bardsley
+ */
+
+#include <cstdlib>
+#include <iostream>
+
+#include "base/statistics.hh"
+#include "sim/cxx_config_ini.hh"
+#include "sim/cxx_manager.hh"
+#include "sim/init_signals.hh"
+#include "sim/stat_control.hh"
+#include "sc_gem5_control.hh"
+#include "sc_logger.hh"
+#include "sc_module.hh"
+#include "stats.hh"
+
+namespace Gem5SystemC
+{
+
+/** This is the private side of Gem5Control */
+class Gem5TopLevelModule : public Gem5SystemC::Module
+{
+    friend class Gem5Control;
+
+  protected:
+    CxxConfigFileBase *config_file;
+    CxxConfigManager *root_manager;
+    Gem5SystemC::Logger logger;
+
+  public:
+    SC_HAS_PROCESS(Gem5TopLevelModule);
+
+    Gem5TopLevelModule(sc_core::sc_module_name name,
+        const std::string &config_filename);
+    ~Gem5TopLevelModule();
+
+    /** gem5 simulate.  @todo for more interesting simulation control,
+     *  this needs to be more complicated */
+    void run();
+};
+
+Gem5System::Gem5System(CxxConfigManager *manager_,
+    const std::string &system_name, const std::string &instance_name) :
+    manager(manager_),
+    systemName(system_name),
+    instanceName(instance_name)
+{
+    manager->addRenaming(CxxConfigManager::Renaming(
+        system_name, instance_name));
+}
+
+Gem5System::~Gem5System()
+{
+    delete manager;
+}
+
+void Gem5System::setParam(const std::string &object,
+    const std::string &param_name, const std::string &param_value)
+{
+    manager->setParam(systemName + (object != "" ? "." + object : ""),
+        param_name, param_value);
+}
+
+void Gem5System::setParamVector(const std::string &object,
+    const std::string &param_name,
+    const std::vector<std::string> &param_values)
+{
+    manager->setParamVector(systemName +
+        (object != "" ? "." + object : ""), param_name, param_values);
+}
+
+void Gem5System::instantiate()
+{
+    try {
+        /* Make a new System */
+        SimObject *obj = manager->findObject(systemName, true);
+
+        /* Add the System's objects to the list of managed
+         *  objects for initialisation */
+        manager->findTraversalOrder(systemName);
+
+        /* Bound ports *must* be internal to System */
+        for (auto i = manager->objectsInOrder.begin();
+             i != manager->objectsInOrder.end();
+             ++ i)
+        {
+            manager->bindObjectPorts(*i);
+        }
+
+        /* gem5 startup sequence */
+        manager->instantiate(false);
+        manager->initState();
+        manager->startup();
+    } catch (CxxConfigManager::Exception &e) {
+        fatal("Config problem in Gem5System: %s: %s",
+            e.name, e.message);
+    }
+}
+
+Gem5Control::Gem5Control(const std::string &config_filename)
+{
+    module = new Gem5TopLevelModule("gem5", config_filename);
+}
+
+Gem5Control::~Gem5Control()
+{ }
+
+void
+Gem5Control::setDebugFlag(const char *flag)
+{
+    ::setDebugFlag(flag);
+}
+
+void
+Gem5Control::clearDebugFlag(const char *flag)
+{
+    ::clearDebugFlag(flag);
+}
+
+Gem5System *
+Gem5Control::makeSystem(const std::string &system_name,
+    const std::string &instance_name)
+{
+    Gem5System *ret = new Gem5System(
+        new CxxConfigManager(*(module->config_file)),
+        system_name, instance_name);
+
+    return ret;
+}
+
+Gem5TopLevelModule::Gem5TopLevelModule(sc_core::sc_module_name name,
+    const std::string &config_filename) :
+    Gem5SystemC::Module(name),
+    config_file(NULL),
+    root_manager(NULL)
+{
+    SC_THREAD(run);
+
+    cxxConfigInit();
+
+    /* Pass DPRINTF messages to SystemC */
+    Trace::setDebugLogger(&logger);
+
+    /* @todo need this as an option */
+    Gem5SystemC::setTickFrequency();
+    sc_core::sc_set_time_resolution(1, sc_core::SC_PS);
+
+    /* Make a SystemC-synchronising event queue and install it as the
+     *  sole top level gem5 EventQueue */
+    Gem5SystemC::Module::setupEventQueues(*this);
+
+    /* Enable keyboard interrupt, async I/O etc. */
+    initSignals();
+
+    /* Enable stats */
+    Stats::initSimStats();
+    Stats::registerHandlers(CxxConfig::statsReset, CxxConfig::statsDump);
+
+    Trace::enabled = true;
+
+    config_file = new CxxIniFile();
+
+    if (!config_file->load(config_filename)) {
+        fatal("Gem5TopLevelModule: Can't open config file: %s",
+            config_filename);
+    }
+
+    root_manager = new CxxConfigManager(*config_file);
+
+    CxxConfig::statsEnable();
+
+    /* Make the root object */
+    try {
+        SimObject *root = root_manager->findObject("root", false);
+
+        /* Make sure we don't traverse into root's children */
+        root_manager->objectsInOrder.push_back(root);
+
+        root_manager->instantiate(false);
+        root_manager->initState();
+        root_manager->startup();
+    } catch (CxxConfigManager::Exception &e) {
+        fatal("Config problem in Gem5TopLevelModule: %s: %s",
+            e.name, e.message);
+    }
+}
+
+Gem5TopLevelModule::~Gem5TopLevelModule()
+{
+    delete config_file;
+    delete root_manager;
+}
+
+void Gem5TopLevelModule::run()
+{
+    GlobalSimLoopExitEvent *exit_event = NULL;
+
+    exit_event = simulate();
+
+    std::cerr << "Exit at tick " << curTick()
+        << ", cause: " << exit_event->getCause() << '\n';
+
+    getEventQueue(0)->dump();
+}
+
+}
+
+Gem5SystemC::Gem5Control *makeGem5Control(const std::string &config_filename)
+{
+    return new Gem5SystemC::Gem5Control(config_filename);
+}
+