src/base/remote_gdb.hh - public/gem5 - Git at Google

 /*
  * Copyright (c) 2018 ARM Limited
  *
  * 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 2015, 2021 LabWare
  * Copyright 2014 Google, Inc.
  * Copyright (c) 2002-2005 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.
  */

 #ifndef __REMOTE_GDB_HH__
 #define __REMOTE_GDB_HH__


 #include <cstdint>
 #include <exception>
 #include <map>
 #include <string>
 #include <vector>

 #include "arch/generic/pcstate.hh"
 #include "base/cprintf.hh"
 #include "base/pollevent.hh"
 #include "base/socket.hh"
 #include "base/types.hh"
 #include "cpu/pc_event.hh"
 #include "gdbremote/signals.hh"
 #include "sim/debug.hh"
 #include "sim/eventq.hh"

 /*
  * This file implements a client for the GDB remote serial protocol as
  * described in this official documentation:
  *
  * https://sourceware.org/gdb/current/onlinedocs/gdb/Remote-Protocol.html
  */

 namespace gem5
 {

 class System;
 class ThreadContext;

 class BaseRemoteGDB;
 class HardBreakpoint;

 /**
  * Concrete subclasses of this abstract class represent how the
  * register values are transmitted on the wire.  Usually each
  * architecture should define one subclass, but there can be more
  * if there is more than one possible wire format.  For example,
  * ARM defines both AArch32GdbRegCache and AArch64GdbRegCache.
  */
 class BaseGdbRegCache
 {
   public:

     /**
      * Return the pointer to the raw bytes buffer containing the
      * register values.  Each byte of this buffer is literally
      * encoded as two hex digits in the g or G RSP packet.
      *
      * @ingroup api_remote_gdb
      */
     virtual char *data() const = 0;

     /**
      * Return the size of the raw buffer, in bytes
      * (i.e., half of the number of digits in the g/G packet).
      *
      * @ingroup api_remote_gdb
      */
     virtual size_t size() const = 0;

     /**
      * Fill the raw buffer from the registers in the ThreadContext.
      *
      * @ingroup api_remote_gdb
      */
     virtual void getRegs(ThreadContext*) = 0;

     /**
      * Set the ThreadContext's registers from the values
      * in the raw buffer.
      *
      * @ingroup api_remote_gdb
      */
     virtual void setRegs(ThreadContext*) const = 0;

     /**
      * Return the name to use in places like DPRINTF.
      * Having each concrete superclass redefine this member
      * is useful in situations where the class of the regCache
      * can change on the fly.
      *
      * @ingroup api_remote_gdb
      */
     virtual const std::string name() const = 0;

     /**
      * @ingroup api_remote_gdb
      */
     BaseGdbRegCache(BaseRemoteGDB *g) : gdb(g)
     {}
     virtual ~BaseGdbRegCache()
     {}

   protected:
     BaseRemoteGDB *gdb;
 };

 class BaseRemoteGDB
 {
     friend class HardBreakpoint;
   public:

     /**
      * @ingroup api_remote_gdb
      * @{
      */

     /**
      * Interface to other parts of the simulator.
      */
     BaseRemoteGDB(System *system, ListenSocketConfig _listen_config);
     virtual ~BaseRemoteGDB();

     std::string name();

     void listen();
     void connect();

     const ListenSocket &hostSocket() const;

     void attach(int fd);
     void detach();
     bool isAttached() { return attached; }

     void addThreadContext(ThreadContext *_tc);
     void replaceThreadContext(ThreadContext *_tc);
     bool selectThreadContext(ContextID id);

     void trap(ContextID id, GDBSignal sig,const std::string& stopReason="");
     bool sendMessage(std::string message);
     //schedule a trap event with these properties
     void scheduleTrapEvent(ContextID id,GDBSignal type, int delta,
       std::string stopReason);
     /** @} */ // end of api_remote_gdb

     template <class GDBStub, class ...Args>
     static BaseRemoteGDB *
     build(ListenSocketConfig listen_config, Args... args)
     {
         if (listen_config)
             return new GDBStub(args..., listen_config);
         else
             return nullptr;
     }

   protected:
     /*
      * Connection to the external GDB.
      */

     /*
      * Asynchronous socket events and event handlers.
      *
      * These events occur asynchronously and are handled asynchronously
      * to main simulation loop - therefore they *shall not* interact with
      * rest of gem5.
      *
      * The only thing they do is to schedule a synchronous event at instruction
      * boundary to deal with the request.
      */
     void incomingData(int revent);
     void incomingConnection(int revent);

     template <void (BaseRemoteGDB::*F)(int revent)>
     class SocketEvent : public PollEvent
     {
       protected:
         BaseRemoteGDB *gdb;

       public:
         SocketEvent(BaseRemoteGDB *gdb, int fd, int e) :
             PollEvent(fd, e), gdb(gdb)
         {}

         void process(int revent) { (gdb->*F)(revent); }
     };

     typedef SocketEvent<&BaseRemoteGDB::incomingConnection>
         IncomingConnectionEvent;
     typedef SocketEvent<&BaseRemoteGDB::incomingData>
         IncomingDataEvent;

     friend IncomingConnectionEvent;
     friend IncomingDataEvent;

     IncomingConnectionEvent *incomingConnectionEvent;
     IncomingDataEvent *incomingDataEvent;

     ListenSocketPtr listener;

     // The socket commands come in through.
     int fd;

     // Transfer data to/from GDB.
     uint8_t getbyte();
     bool try_getbyte(uint8_t* c,int timeout=-1);//return true if successful
     void putbyte(uint8_t b);

     void recv(std::vector<char> &bp);
     void send(const char *data);
     void send(const std::string &data) { send(data.c_str()); }

     template <typename ...Args>
     void
     send(const char *format, const Args &...args)
     {
         send(csprintf(format, args...));
     }

     /*
      * Process commands from remote GDB. If simulation has been
      * stopped because of some kind of fault (as segmentation violation,
      * or SW trap), 'signum' is the signal value reported back to GDB
      * in "S" packet (this is done in trap()).
      */
     void processCommands(GDBSignal sig=GDBSignal::ZERO);

     /*
      * Simulator side debugger state.
      */
     bool attached = false;
     bool threadSwitching = false;

     System *sys;

     std::map<ContextID, ThreadContext *> threads;
     ThreadContext *tc = nullptr;

     BaseGdbRegCache *regCachePtr = nullptr;

     MemberEventWrapper<&BaseRemoteGDB::connect> connectEvent;
     MemberEventWrapper<&BaseRemoteGDB::detach>  disconnectEvent;

     class TrapEvent : public Event
     {
       protected:
         GDBSignal _type;
         ContextID _id;
         std::string _stopReason;
         BaseRemoteGDB *gdb;

       public:
         TrapEvent(BaseRemoteGDB *g) : gdb(g)
         {}

         void type(GDBSignal t) { _type = t; }
         void stopReason(std::string s) {_stopReason = s; }
         void id(ContextID id) { _id = id; }
          void process() { gdb->trap(_id, _type,_stopReason); }
     } trapEvent;

     /*
      * The interface to the simulated system.
      */
     virtual bool readBlob(Addr vaddr, size_t size, char *data);
     virtual bool writeBlob(Addr vaddr, size_t size, const char *data);
     bool read(Addr vaddr, size_t size, char *data);
     bool write(Addr vaddr, size_t size, const char *data);

     template <class T> T read(Addr addr);
     template <class T> void write(Addr addr, T data);

     // Single step.
     void singleStep();
     MemberEventWrapper<&BaseRemoteGDB::singleStep> singleStepEvent;

     void clearSingleStep();
     void setSingleStep();

     /// Schedule an event which will be triggered "delta" instructions later.
     void scheduleInstCommitEvent(Event *ev, int delta,ThreadContext* _tc);
     void scheduleInstCommitEvent(Event *ev, int delta){
        scheduleInstCommitEvent(ev, delta,tc);
     };
     /// Deschedule an instruction count based event.
     void descheduleInstCommitEvent(Event *ev);

     // Breakpoints.
     void insertSoftBreak(Addr addr, size_t kind);
     void removeSoftBreak(Addr addr, size_t kind);
     void insertHardBreak(Addr addr, size_t kind);
     void removeHardBreak(Addr addr, size_t kind);

     void sendTPacket(GDBSignal sig, ContextID id,
       const std::string& stopReason);
     void sendSPacket(GDBSignal sig);
     //The OPacket allow to send string to be displayed by the remote GDB
     void sendOPacket(const std::string message);
     /*
      * GDB commands.
      */
     struct GdbCommand
     {
       public:
         struct Context
         {
             const GdbCommand *cmd;
             char cmdByte;
             GDBSignal type;
             char *data;
             int len;
         };

         typedef bool (BaseRemoteGDB::*Func)(Context &ctx);

         const char * const name;
         const Func func;

         GdbCommand(const char *_name, Func _func) : name(_name), func(_func) {}
     };

     static std::map<char, GdbCommand> commandMap;

     struct GdbMultiLetterCommand
     {
       public:
         struct Context
         {
             const GdbMultiLetterCommand *cmd;
             std::string cmdTxt;
             GDBSignal type;
             char *data;
             int len;
         };

         typedef bool (BaseRemoteGDB::*Func)(Context &ctx);

         const char * const name;
         const Func func;

         GdbMultiLetterCommand(const char *_name, Func _func) :
           name(_name), func(_func) {}
     };


     static std::map<std::string, GdbMultiLetterCommand> multiLetterMap;

     bool cmdUnsupported(GdbCommand::Context &ctx);

     bool cmdSignal(GdbCommand::Context &ctx);
     bool cmdCont(GdbCommand::Context &ctx);
     bool cmdAsyncCont(GdbCommand::Context &ctx);
     bool cmdDetach(GdbCommand::Context &ctx);
     bool cmdRegR(GdbCommand::Context &ctx);
     bool cmdRegW(GdbCommand::Context &ctx);
     bool cmdSetThread(GdbCommand::Context &ctx);
     bool cmdIsThreadAlive(GdbCommand::Context &ctx);
     bool cmdMemR(GdbCommand::Context &ctx);
     bool cmdMemW(GdbCommand::Context &ctx);
     bool cmdQueryVar(GdbCommand::Context &ctx);
     bool cmdStep(GdbCommand::Context &ctx);
     bool cmdAsyncStep(GdbCommand::Context &ctx);
     bool cmdClrHwBkpt(GdbCommand::Context &ctx);
     bool cmdSetHwBkpt(GdbCommand::Context &ctx);
     bool cmdDumpPageTable(GdbCommand::Context &ctx);
     bool cmdMultiLetter(GdbCommand::Context &ctx);

     //Multi letter command
     bool cmdMultiUnsupported(GdbMultiLetterCommand::Context &ctx);

     bool cmdReplyEmpty(GdbMultiLetterCommand::Context &ctx);
     bool cmdVKill(GdbMultiLetterCommand::Context &ctx);

     struct QuerySetCommand
     {
         struct Context
         {
             const std::string &name;
             std::vector<std::string> args;

             Context(const std::string &_name) : name(_name) {}
         };

         using Func = bool (BaseRemoteGDB::*)(Context &ctx);

         const char * const argSep;
         const Func func;

         QuerySetCommand(Func _func, const char *_argSep=nullptr) :
             argSep(_argSep), func(_func)
         {}
     };

     static std::map<std::string, QuerySetCommand> queryMap;

     bool queryC(QuerySetCommand::Context &ctx);
     bool querySupported(QuerySetCommand::Context &ctx);
     bool queryXfer(QuerySetCommand::Context &ctx);
     bool querySymbol(QuerySetCommand::Context &ctx);
     bool queryRcmd(QuerySetCommand::Context &ctx);
     bool queryAttached(QuerySetCommand::Context &ctx);

     size_t threadInfoIdx = 0;
     bool queryFThreadInfo(QuerySetCommand::Context &ctx);
     bool querySThreadInfo(QuerySetCommand::Context &ctx);

   protected:
     ThreadContext *context() { return tc; }
     System *system() { return sys; }

     void encodeBinaryData(const std::string &unencoded,
             std::string &encoded) const;

     void encodeXferResponse(const std::string &unencoded,
         std::string &encoded, size_t offset, size_t unencoded_length) const;

     // checkBpKind checks if a kind of breakpoint is legal. This function should
     // be implemented by subclasses by arch. The "kind" is considered to be
     // breakpoint size in some arch.
     virtual bool checkBpKind(size_t kind);

     virtual BaseGdbRegCache *gdbRegs() = 0;

     virtual bool acc(Addr addr, size_t len) = 0;

     virtual std::vector<std::string> availableFeatures() const;

     /**
      * Get an XML target description.
      *
      * @param[in] annex the XML filename
      * @param[out] output set to the decoded XML
      * @return true if the given annex was found
      */
     virtual bool getXferFeaturesRead(const std::string &annex,
             std::string &output);
 };

 template <class T>
 inline T
 BaseRemoteGDB::read(Addr addr)
 {
     T temp;
     read(addr, sizeof(T), (char *)&temp);
     return temp;
 }

 template <class T>
 inline void
 BaseRemoteGDB::write(Addr addr, T data)
 {
     write(addr, sizeof(T), (const char *)&data);
 }

 } // namespace gem5

 #endif /* __REMOTE_GDB_H__ */
	/*
	* Copyright (c) 2018 ARM Limited
	*
	* 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 2015, 2021 LabWare
	* Copyright 2014 Google, Inc.
	* Copyright (c) 2002-2005 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.
	*/

	#ifndef __REMOTE_GDB_HH__
	#define __REMOTE_GDB_HH__


	#include <cstdint>
	#include <exception>
	#include <map>
	#include <string>
	#include <vector>

	#include "arch/generic/pcstate.hh"
	#include "base/cprintf.hh"
	#include "base/pollevent.hh"
	#include "base/socket.hh"
	#include "base/types.hh"
	#include "cpu/pc_event.hh"
	#include "gdbremote/signals.hh"
	#include "sim/debug.hh"
	#include "sim/eventq.hh"

	/*
	* This file implements a client for the GDB remote serial protocol as
	* described in this official documentation:
	*
	* https://sourceware.org/gdb/current/onlinedocs/gdb/Remote-Protocol.html
	*/

	namespace gem5
	{

	class System;
	class ThreadContext;

	class BaseRemoteGDB;
	class HardBreakpoint;

	/**
	* Concrete subclasses of this abstract class represent how the
	* register values are transmitted on the wire. Usually each
	* architecture should define one subclass, but there can be more
	* if there is more than one possible wire format. For example,
	* ARM defines both AArch32GdbRegCache and AArch64GdbRegCache.
	*/
	class BaseGdbRegCache
	{
	public:

	/**
	* Return the pointer to the raw bytes buffer containing the
	* register values. Each byte of this buffer is literally
	* encoded as two hex digits in the g or G RSP packet.
	*
	* @ingroup api_remote_gdb
	*/
	virtual char *data() const = 0;

	/**
	* Return the size of the raw buffer, in bytes
	* (i.e., half of the number of digits in the g/G packet).
	*
	* @ingroup api_remote_gdb
	*/
	virtual size_t size() const = 0;

	/**
	* Fill the raw buffer from the registers in the ThreadContext.
	*
	* @ingroup api_remote_gdb
	*/
	virtual void getRegs(ThreadContext*) = 0;

	/**
	* Set the ThreadContext's registers from the values
	* in the raw buffer.
	*
	* @ingroup api_remote_gdb
	*/
	virtual void setRegs(ThreadContext*) const = 0;

	/**
	* Return the name to use in places like DPRINTF.
	* Having each concrete superclass redefine this member
	* is useful in situations where the class of the regCache
	* can change on the fly.
	*
	* @ingroup api_remote_gdb
	*/
	virtual const std::string name() const = 0;

	/**
	* @ingroup api_remote_gdb
	*/
	BaseGdbRegCache(BaseRemoteGDB *g) : gdb(g)
	{}
	virtual ~BaseGdbRegCache()
	{}

	protected:
	BaseRemoteGDB *gdb;
	};

	class BaseRemoteGDB
	{
	friend class HardBreakpoint;
	public:

	/**
	* @ingroup api_remote_gdb
	* @{
	*/

	/**
	* Interface to other parts of the simulator.
	*/
	BaseRemoteGDB(System *system, ListenSocketConfig _listen_config);
	virtual ~BaseRemoteGDB();

	std::string name();

	void listen();
	void connect();

	const ListenSocket &hostSocket() const;

	void attach(int fd);
	void detach();
	bool isAttached() { return attached; }

	void addThreadContext(ThreadContext *_tc);
	void replaceThreadContext(ThreadContext *_tc);
	bool selectThreadContext(ContextID id);

	void trap(ContextID id, GDBSignal sig,const std::string& stopReason="");
	bool sendMessage(std::string message);
	//schedule a trap event with these properties
	void scheduleTrapEvent(ContextID id,GDBSignal type, int delta,
	std::string stopReason);
	/** @} */ // end of api_remote_gdb

	template <class GDBStub, class ...Args>
	static BaseRemoteGDB *
	build(ListenSocketConfig listen_config, Args... args)
	{
	if (listen_config)
	return new GDBStub(args..., listen_config);
	else
	return nullptr;
	}

	protected:
	/*
	* Connection to the external GDB.
	*/

	/*
	* Asynchronous socket events and event handlers.
	*
	* These events occur asynchronously and are handled asynchronously
	* to main simulation loop - therefore they shall not interact with
	* rest of gem5.
	*
	* The only thing they do is to schedule a synchronous event at instruction
	* boundary to deal with the request.
	*/
	void incomingData(int revent);
	void incomingConnection(int revent);

	template <void (BaseRemoteGDB::*F)(int revent)>
	class SocketEvent : public PollEvent
	{
	protected:
	BaseRemoteGDB *gdb;

	public:
	SocketEvent(BaseRemoteGDB *gdb, int fd, int e) :
	PollEvent(fd, e), gdb(gdb)
	{}

	void process(int revent) { (gdb->*F)(revent); }
	};

	typedef SocketEvent<&BaseRemoteGDB::incomingConnection>
	IncomingConnectionEvent;
	typedef SocketEvent<&BaseRemoteGDB::incomingData>
	IncomingDataEvent;

	friend IncomingConnectionEvent;
	friend IncomingDataEvent;

	IncomingConnectionEvent *incomingConnectionEvent;
	IncomingDataEvent *incomingDataEvent;

	ListenSocketPtr listener;

	// The socket commands come in through.
	int fd;

	// Transfer data to/from GDB.
	uint8_t getbyte();
	bool try_getbyte(uint8_t* c,int timeout=-1);//return true if successful
	void putbyte(uint8_t b);

	void recv(std::vector<char> &bp);
	void send(const char *data);
	void send(const std::string &data) { send(data.c_str()); }

	template <typename ...Args>
	void
	send(const char *format, const Args &...args)
	{
	send(csprintf(format, args...));
	}

	/*
	* Process commands from remote GDB. If simulation has been
	* stopped because of some kind of fault (as segmentation violation,
	* or SW trap), 'signum' is the signal value reported back to GDB
	* in "S" packet (this is done in trap()).
	*/
	void processCommands(GDBSignal sig=GDBSignal::ZERO);

	/*
	* Simulator side debugger state.
	*/
	bool attached = false;
	bool threadSwitching = false;

	System *sys;

	std::map<ContextID, ThreadContext *> threads;
	ThreadContext *tc = nullptr;

	BaseGdbRegCache *regCachePtr = nullptr;

	MemberEventWrapper<&BaseRemoteGDB::connect> connectEvent;
	MemberEventWrapper<&BaseRemoteGDB::detach> disconnectEvent;

	class TrapEvent : public Event
	{
	protected:
	GDBSignal _type;
	ContextID _id;
	std::string _stopReason;
	BaseRemoteGDB *gdb;

	public:
	TrapEvent(BaseRemoteGDB *g) : gdb(g)
	{}

	void type(GDBSignal t) { _type = t; }
	void stopReason(std::string s) {_stopReason = s; }
	void id(ContextID id) { _id = id; }
	void process() { gdb->trap(_id, _type,_stopReason); }
	} trapEvent;

	/*
	* The interface to the simulated system.
	*/
	virtual bool readBlob(Addr vaddr, size_t size, char *data);
	virtual bool writeBlob(Addr vaddr, size_t size, const char *data);
	bool read(Addr vaddr, size_t size, char *data);
	bool write(Addr vaddr, size_t size, const char *data);

	template <class T> T read(Addr addr);
	template <class T> void write(Addr addr, T data);

	// Single step.
	void singleStep();
	MemberEventWrapper<&BaseRemoteGDB::singleStep> singleStepEvent;

	void clearSingleStep();
	void setSingleStep();

	/// Schedule an event which will be triggered "delta" instructions later.
	void scheduleInstCommitEvent(Event ev, int delta,ThreadContext _tc);
	void scheduleInstCommitEvent(Event *ev, int delta){
	scheduleInstCommitEvent(ev, delta,tc);
	};
	/// Deschedule an instruction count based event.
	void descheduleInstCommitEvent(Event *ev);

	// Breakpoints.
	void insertSoftBreak(Addr addr, size_t kind);
	void removeSoftBreak(Addr addr, size_t kind);
	void insertHardBreak(Addr addr, size_t kind);
	void removeHardBreak(Addr addr, size_t kind);

	void sendTPacket(GDBSignal sig, ContextID id,
	const std::string& stopReason);
	void sendSPacket(GDBSignal sig);
	//The OPacket allow to send string to be displayed by the remote GDB
	void sendOPacket(const std::string message);
	/*
	* GDB commands.
	*/
	struct GdbCommand
	{
	public:
	struct Context
	{
	const GdbCommand *cmd;
	char cmdByte;
	GDBSignal type;
	char *data;
	int len;
	};

	typedef bool (BaseRemoteGDB::*Func)(Context &ctx);

	const char * const name;
	const Func func;

	GdbCommand(const char *_name, Func _func) : name(_name), func(_func) {}
	};

	static std::map<char, GdbCommand> commandMap;

	struct GdbMultiLetterCommand
	{
	public:
	struct Context
	{
	const GdbMultiLetterCommand *cmd;
	std::string cmdTxt;
	GDBSignal type;
	char *data;
	int len;
	};

	typedef bool (BaseRemoteGDB::*Func)(Context &ctx);

	const char * const name;
	const Func func;

	GdbMultiLetterCommand(const char *_name, Func _func) :
	name(_name), func(_func) {}
	};


	static std::map<std::string, GdbMultiLetterCommand> multiLetterMap;

	bool cmdUnsupported(GdbCommand::Context &ctx);

	bool cmdSignal(GdbCommand::Context &ctx);
	bool cmdCont(GdbCommand::Context &ctx);
	bool cmdAsyncCont(GdbCommand::Context &ctx);
	bool cmdDetach(GdbCommand::Context &ctx);
	bool cmdRegR(GdbCommand::Context &ctx);
	bool cmdRegW(GdbCommand::Context &ctx);
	bool cmdSetThread(GdbCommand::Context &ctx);
	bool cmdIsThreadAlive(GdbCommand::Context &ctx);
	bool cmdMemR(GdbCommand::Context &ctx);
	bool cmdMemW(GdbCommand::Context &ctx);
	bool cmdQueryVar(GdbCommand::Context &ctx);
	bool cmdStep(GdbCommand::Context &ctx);
	bool cmdAsyncStep(GdbCommand::Context &ctx);
	bool cmdClrHwBkpt(GdbCommand::Context &ctx);
	bool cmdSetHwBkpt(GdbCommand::Context &ctx);
	bool cmdDumpPageTable(GdbCommand::Context &ctx);
	bool cmdMultiLetter(GdbCommand::Context &ctx);

	//Multi letter command
	bool cmdMultiUnsupported(GdbMultiLetterCommand::Context &ctx);

	bool cmdReplyEmpty(GdbMultiLetterCommand::Context &ctx);
	bool cmdVKill(GdbMultiLetterCommand::Context &ctx);

	struct QuerySetCommand
	{
	struct Context
	{
	const std::string &name;
	std::vector<std::string> args;

	Context(const std::string &_name) : name(_name) {}
	};

	using Func = bool (BaseRemoteGDB::*)(Context &ctx);

	const char * const argSep;
	const Func func;

	QuerySetCommand(Func _func, const char *_argSep=nullptr) :
	argSep(_argSep), func(_func)
	{}
	};

	static std::map<std::string, QuerySetCommand> queryMap;

	bool queryC(QuerySetCommand::Context &ctx);
	bool querySupported(QuerySetCommand::Context &ctx);
	bool queryXfer(QuerySetCommand::Context &ctx);
	bool querySymbol(QuerySetCommand::Context &ctx);
	bool queryRcmd(QuerySetCommand::Context &ctx);
	bool queryAttached(QuerySetCommand::Context &ctx);

	size_t threadInfoIdx = 0;
	bool queryFThreadInfo(QuerySetCommand::Context &ctx);
	bool querySThreadInfo(QuerySetCommand::Context &ctx);

	protected:
	ThreadContext *context() { return tc; }
	System *system() { return sys; }

	void encodeBinaryData(const std::string &unencoded,
	std::string &encoded) const;

	void encodeXferResponse(const std::string &unencoded,
	std::string &encoded, size_t offset, size_t unencoded_length) const;

	// checkBpKind checks if a kind of breakpoint is legal. This function should
	// be implemented by subclasses by arch. The "kind" is considered to be
	// breakpoint size in some arch.
	virtual bool checkBpKind(size_t kind);

	virtual BaseGdbRegCache *gdbRegs() = 0;

	virtual bool acc(Addr addr, size_t len) = 0;

	virtual std::vector<std::string> availableFeatures() const;

	/**
	* Get an XML target description.
	*
	* @param[in] annex the XML filename
	* @param[out] output set to the decoded XML
	* @return true if the given annex was found
	*/
	virtual bool getXferFeaturesRead(const std::string &annex,
	std::string &output);
	};

	template <class T>
	inline T
	BaseRemoteGDB::read(Addr addr)
	{
	T temp;
	read(addr, sizeof(T), (char *)&temp);
	return temp;
	}

	template <class T>
	inline void
	BaseRemoteGDB::write(Addr addr, T data)
	{
	write(addr, sizeof(T), (const char *)&data);
	}

	} // namespace gem5

	#endif /* __REMOTE_GDB_H__ */