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/*
* Copyright (c) 2015, 2021 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.
*
* Copyright (c) 2001-2005 The Regents of The University of Michigan
* Copyright (c) 2010 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
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* @file
* User Console Definitions
*/
#ifndef __SIM_OBJECT_HH__
#define __SIM_OBJECT_HH__
#include <string>
#include <vector>
#include "base/named.hh"
#include "base/stats/group.hh"
#include "params/SimObject.hh"
#include "sim/drain.hh"
#include "sim/eventq.hh"
#include "sim/port.hh"
#include "sim/serialize.hh"
namespace gem5
{
class EventManager;
class ProbeManager;
class SimObjectResolver;
/**
* Abstract superclass for simulation objects. Represents things that
* correspond to physical components and can be specified via the
* config file (CPUs, caches, etc.).
*
* SimObject initialization is controlled by the instantiate method in
* src/python/m5/simulate.py. There are slightly different
* initialization paths when starting the simulation afresh and when
* loading from a checkpoint. After instantiation and connecting
* ports, simulate.py initializes the object using the following call
* sequence:
*
* <ol>
* <li>SimObject::init()
* <li>SimObject::regStats()
* <li><ul>
* <li>SimObject::initState() if starting afresh.
* <li>SimObject::loadState() if restoring from a checkpoint.
* </ul>
* <li>SimObject::resetStats()
* <li>SimObject::startup()
* <li>Drainable::drainResume() if resuming from a checkpoint.
* </ol>
*
* @note Whenever a method is called on all objects in the simulator's
* object tree (e.g., init(), startup(), or loadState()), a pre-order
* depth-first traversal is performed (see descendants() in
* SimObject.py). This has the effect of calling the method on the
* parent node <i>before</i> its children.
*
* The python version of a SimObject class actually represents its Params
* structure which holds all its parameter settings and its name. When python
* needs to create a C++ instance of one of those classes, it uses the Params
* struct's create() method which returns one instance, set up with the
* parameters in the struct.
*
* When writing a SimObject class, there are three different cases as far as
* what you need to do to support the create() method, for hypothetical class
* Foo.
*
* If you have a constructor with a signature like this:
*
* Foo(const FooParams &)
*
* you don't have to do anything, a create method will be automatically
* defined which will call your constructor and return that instance. You
* should use this option most of the time.
*
* If you have a constructor with that signature but still want to define
* your own create method for some reason, you can do that by providing an
* alternative implementation which will override the default. It should have
* this signature:
*
* Foo *FooParams::create() const;
*
* If you don't have a constructor with that signature at all, then you must
* implement the create method with that signature which will build your
* object in some other way.
*
* A reference to the SimObjectParams will be returned via the params()
* API. It is quite common for a derived class (DerivSimObject) to access its
* derived parameters by downcasting the SimObjectParam to DerivSimObjectParams
*
* \code{.cpp}
* using Params = DerivSimObjectParams;
* const Params &
* params() const
* {
* return reinterpret_cast<const Params&>(_params);
* }
* \endcode
*
* We provide the PARAMS(..) macro as syntactic sugar to replace the code
* above with a much simpler:
*
* \code{.cpp}
* PARAMS(DerivSimObject);
* \endcode
*/
class SimObject : public EventManager, public Serializable, public Drainable,
public statistics::Group, public Named
{
private:
typedef std::vector<SimObject *> SimObjectList;
/** List of all instantiated simulation objects. */
static SimObjectList simObjectList;
/** Helper to resolve an object given its name. */
static SimObjectResolver *_objNameResolver;
/** Manager coordinates hooking up probe points with listeners. */
ProbeManager *probeManager;
protected:
/**
* Cached copy of the object parameters.
*
* @ingroup api_simobject
*/
const SimObjectParams &_params;
public:
typedef SimObjectParams Params;
/**
* @return This function returns the cached copy of the object parameters.
*
* @ingroup api_simobject
*/
const Params &params() const { return _params; }
/**
* @ingroup api_simobject
*/
SimObject(const Params &p);
virtual ~SimObject();
public:
/**
* init() is called after all C++ SimObjects have been created and
* all ports are connected. Initializations that are independent
* of unserialization but rely on a fully instantiated and
* connected SimObject graph should be done here.
*
* @ingroup api_simobject
*/
virtual void init();
/**
* loadState() is called on each SimObject when restoring from a
* checkpoint. The default implementation simply calls
* unserialize() if there is a corresponding section in the
* checkpoint. However, objects can override loadState() to get
* other behaviors, e.g., doing other programmed initializations
* after unserialize(), or complaining if no checkpoint section is
* found.
*
* @param cp Checkpoint to restore the state from.
*
* @ingroup api_serialize
*/
virtual void loadState(CheckpointIn &cp);
/**
* initState() is called on each SimObject when *not* restoring
* from a checkpoint. This provides a hook for state
* initializations that are only required for a "cold start".
*
* @ingroup api_serialize
*/
virtual void initState();
/**
* Register probe points for this object.
*
* @ingroup api_simobject
*/
virtual void regProbePoints();
/**
* Register probe listeners for this object.
*
* @ingroup api_simobject
*/
virtual void regProbeListeners();
/**
* Get the probe manager for this object.
*
* Probes generate traces. A trace is a file that
* keeps a log of events. For example, we can have a probe
* listener for an address and the trace will be a file that
* has time stamps for all the reads and writes to that address.
*
* @ingroup api_simobject
*/
ProbeManager *getProbeManager();
/**
* Get a port with a given name and index. This is used at binding time
* and returns a reference to a protocol-agnostic port.
*
* gem5 has a request and response port interface. All memory objects
* are connected together via ports. These ports provide a rigid
* interface between these memory objects. These ports implement
* three different memory system modes: timing, atomic, and
* functional. The most important mode is the timing mode and here
* timing mode is used for conducting cycle-level timing
* experiments. The other modes are only used in special
* circumstances and should *not* be used to conduct cycle-level
* timing experiments. The other modes are only used in special
* circumstances. These ports allow SimObjects to communicate with
* each other.
*
* @param if_name Port name
* @param idx Index in the case of a VectorPort
*
* @return A reference to the given port
*
* @ingroup api_simobject
*/
virtual Port &getPort(const std::string &if_name,
PortID idx=InvalidPortID);
/**
* startup() is the final initialization call before simulation.
* All state is initialized (including unserialized state, if any,
* such as the curTick() value), so this is the appropriate place to
* schedule initial event(s) for objects that need them.
*
* @ingroup api_simobject
*/
virtual void startup();
/**
* Provide a default implementation of the drain interface for
* objects that don't need draining.
*/
DrainState drain() override { return DrainState::Drained; }
/**
* Write back dirty buffers to memory using functional writes.
*
* After returning, an object implementing this method should have
* written all its dirty data back to memory. This method is
* typically used to prepare a system with caches for
* checkpointing.
*
* @ingroup api_simobject
*/
virtual void memWriteback() {};
/**
* Invalidate the contents of memory buffers.
*
* When the switching to hardware virtualized CPU models, we need
* to make sure that we don't have any cached state in the system
* that might become stale when we return. This method is used to
* flush all such state back to main memory.
*
* @warn This does <i>not</i> cause any dirty state to be written
* back to memory.
*
* @ingroup api_simobject
*/
virtual void memInvalidate() {};
void serialize(CheckpointOut &cp) const override {};
void unserialize(CheckpointIn &cp) override {};
/**
* Create a checkpoint by serializing all SimObjects in the system.
*
* This is the entry point in the process of checkpoint creation,
* so it will create the checkpoint file and then unfold into
* the serialization of all the sim objects declared.
*
* Each SimObject instance is explicitly and individually serialized
* in its own section. As such, the serialization functions should not
* be called on sim objects anywhere else; otherwise, these objects
* would be needlessly serialized more than once.
*/
static void serializeAll(const std::string &cpt_dir);
/**
* Find the SimObject with the given name and return a pointer to
* it. Primarily used for interactive debugging. Argument is
* char* rather than std::string to make it callable from gdb.
*
* @ingroup api_simobject
*/
static SimObject *find(const char *name);
/**
* There is a single object name resolver, and it is only set when
* simulation is restoring from checkpoints.
*
* @param Pointer to the single sim object name resolver.
*/
static void setSimObjectResolver(SimObjectResolver *resolver);
/**
* There is a single object name resolver, and it is only set when
* simulation is restoring from checkpoints.
*
* @return Pointer to the single sim object name resolver.
*/
static SimObjectResolver *getSimObjectResolver();
};
/* Add PARAMS(ClassName) to every descendant of SimObject that needs
* params.
*
* Strictly speaking, we need static_cast here, because the types are
* related by inheritance, but since the target type may be
* incomplete, the compiler does not know the relation.
*/
#define PARAMS(type) \
using Params = type ## Params; \
const Params & \
params() const \
{ \
return reinterpret_cast<const Params&>(_params); \
}
/**
* Base class to wrap object resolving functionality.
*
* This can be provided to the serialization framework to allow it to
* map object names onto C++ objects.
*/
class SimObjectResolver
{
public:
virtual ~SimObjectResolver() { }
/**
* Find a SimObject given a full path name
*
* @ingroup api_serialize
*/
virtual SimObject *resolveSimObject(const std::string &name) = 0;
};
/**
* To avoid circular dependencies the unserialization of SimObjects must be
* implemented here.
*
* @ingroup api_serialize
*/
void objParamIn(CheckpointIn &cp, const std::string &name, SimObject * &param);
void debug_serialize(const std::string &cpt_dir);
} // namespace gem5
#endif // __SIM_OBJECT_HH__