src/cpu/checker/cpu.hh - public/gem5 - Git at Google

 /*
  * Copyright (c) 2011, 2016-2017 ARM Limited
  * Copyright (c) 2013 Advanced Micro Devices, Inc.
  * 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) 2006 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.
  *
  * Authors: Kevin Lim
  */

 #ifndef __CPU_CHECKER_CPU_HH__
 #define __CPU_CHECKER_CPU_HH__

 #include <list>
 #include <map>
 #include <queue>

 #include "arch/types.hh"
 #include "base/statistics.hh"
 #include "cpu/base.hh"
 #include "cpu/base_dyn_inst.hh"
 #include "cpu/exec_context.hh"
 #include "cpu/inst_res.hh"
 #include "cpu/pc_event.hh"
 #include "cpu/simple_thread.hh"
 #include "cpu/static_inst.hh"
 #include "debug/Checker.hh"
 #include "mem/request.hh"
 #include "params/CheckerCPU.hh"
 #include "sim/eventq.hh"

 class BaseTLB;
 template <class>
 class BaseDynInst;
 class ThreadContext;
 class Request;

 /**
  * CheckerCPU class.  Dynamically verifies instructions as they are
  * completed by making sure that the instruction and its results match
  * the independent execution of the benchmark inside the checker.  The
  * checker verifies instructions in order, regardless of the order in
  * which instructions complete.  There are certain results that can
  * not be verified, specifically the result of a store conditional or
  * the values of uncached accesses.  In these cases, and with
  * instructions marked as "IsUnverifiable", the checker assumes that
  * the value from the main CPU's execution is correct and simply
  * copies that value.  It provides a CheckerThreadContext (see
  * checker/thread_context.hh) that provides hooks for updating the
  * Checker's state through any ThreadContext accesses.  This allows the
  * checker to be able to correctly verify instructions, even with
  * external accesses to the ThreadContext that change state.
  */
 class CheckerCPU : public BaseCPU, public ExecContext
 {
   protected:
     typedef TheISA::MachInst MachInst;
     using VecRegContainer = TheISA::VecRegContainer;

     /** id attached to all issued requests */
     MasterID masterId;
   public:
     void init() override;

     typedef CheckerCPUParams Params;
     CheckerCPU(Params *p);
     virtual ~CheckerCPU();

     void setSystem(System *system);

     void setIcachePort(MasterPort *icache_port);

     void setDcachePort(MasterPort *dcache_port);

     MasterPort &getDataPort() override
     {
         // the checker does not have ports on its own so return the
         // data port of the actual CPU core
         assert(dcachePort);
         return *dcachePort;
     }

     MasterPort &getInstPort() override
     {
         // the checker does not have ports on its own so return the
         // data port of the actual CPU core
         assert(icachePort);
         return *icachePort;
     }

   protected:

     std::vector<Process*> workload;

     System *systemPtr;

     MasterPort *icachePort;
     MasterPort *dcachePort;

     ThreadContext *tc;

     BaseTLB *itb;
     BaseTLB *dtb;

     Addr dbg_vtophys(Addr addr);

     // ISAs like ARM can have multiple destination registers to check,
     // keep them all in a std::queue
     std::queue<InstResult> result;

     StaticInstPtr curStaticInst;
     StaticInstPtr curMacroStaticInst;

     // number of simulated instructions
     Counter numInst;
     Counter startNumInst;

     std::queue<int> miscRegIdxs;

   public:

     // Primary thread being run.
     SimpleThread *thread;

     BaseTLB* getITBPtr() { return itb; }
     BaseTLB* getDTBPtr() { return dtb; }

     virtual Counter totalInsts() const override
     {
         return 0;
     }

     virtual Counter totalOps() const override
     {
         return 0;
     }

     // number of simulated loads
     Counter numLoad;
     Counter startNumLoad;

     void serialize(CheckpointOut &cp) const override;
     void unserialize(CheckpointIn &cp) override;

     // The register accessor methods provide the index of the
     // instruction's operand (e.g., 0 or 1), not the architectural
     // register index, to simplify the implementation of register
     // renaming.  We find the architectural register index by indexing
     // into the instruction's own operand index table.  Note that a
     // raw pointer to the StaticInst is provided instead of a
     // ref-counted StaticInstPtr to redice overhead.  This is fine as
     // long as these methods don't copy the pointer into any long-term
     // storage (which is pretty hard to imagine they would have reason
     // to do).

     RegVal
     readIntRegOperand(const StaticInst *si, int idx) override
     {
         const RegId& reg = si->srcRegIdx(idx);
         assert(reg.isIntReg());
         return thread->readIntReg(reg.index());
     }

     RegVal
     readFloatRegOperandBits(const StaticInst *si, int idx) override
     {
         const RegId& reg = si->srcRegIdx(idx);
         assert(reg.isFloatReg());
         return thread->readFloatReg(reg.index());
     }

     /**
      * Read source vector register operand.
      */
     const VecRegContainer &
     readVecRegOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->srcRegIdx(idx);
         assert(reg.isVecReg());
         return thread->readVecReg(reg);
     }

     /**
      * Read destination vector register operand for modification.
      */
     VecRegContainer &
     getWritableVecRegOperand(const StaticInst *si, int idx) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         return thread->getWritableVecReg(reg);
     }

     /** Vector Register Lane Interfaces. */
     /** @{ */
     /** Reads source vector 8bit operand. */
     virtual ConstVecLane8
     readVec8BitLaneOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         return thread->readVec8BitLaneReg(reg);
     }

     /** Reads source vector 16bit operand. */
     virtual ConstVecLane16
     readVec16BitLaneOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         return thread->readVec16BitLaneReg(reg);
     }

     /** Reads source vector 32bit operand. */
     virtual ConstVecLane32
     readVec32BitLaneOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         return thread->readVec32BitLaneReg(reg);
     }

     /** Reads source vector 64bit operand. */
     virtual ConstVecLane64
     readVec64BitLaneOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         return thread->readVec64BitLaneReg(reg);
     }

     /** Write a lane of the destination vector operand. */
     template <typename LD>
     void
     setVecLaneOperandT(const StaticInst *si, int idx, const LD& val)
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         return thread->setVecLane(reg, val);
     }
     virtual void
     setVecLaneOperand(const StaticInst *si, int idx,
             const LaneData<LaneSize::Byte>& val) override
     {
         setVecLaneOperandT(si, idx, val);
     }
     virtual void
     setVecLaneOperand(const StaticInst *si, int idx,
             const LaneData<LaneSize::TwoByte>& val) override
     {
         setVecLaneOperandT(si, idx, val);
     }
     virtual void
     setVecLaneOperand(const StaticInst *si, int idx,
             const LaneData<LaneSize::FourByte>& val) override
     {
         setVecLaneOperandT(si, idx, val);
     }
     virtual void
     setVecLaneOperand(const StaticInst *si, int idx,
             const LaneData<LaneSize::EightByte>& val) override
     {
         setVecLaneOperandT(si, idx, val);
     }
     /** @} */

     VecElem
     readVecElemOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->srcRegIdx(idx);
         return thread->readVecElem(reg);
     }

     const VecPredRegContainer&
     readVecPredRegOperand(const StaticInst *si, int idx) const override
     {
         const RegId& reg = si->srcRegIdx(idx);
         assert(reg.isVecPredReg());
         return thread->readVecPredReg(reg);
     }

     VecPredRegContainer&
     getWritableVecPredRegOperand(const StaticInst *si, int idx) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecPredReg());
         return thread->getWritableVecPredReg(reg);
     }

     RegVal
     readCCRegOperand(const StaticInst *si, int idx) override
     {
         const RegId& reg = si->srcRegIdx(idx);
         assert(reg.isCCReg());
         return thread->readCCReg(reg.index());
     }

     template<typename T>
     void
     setScalarResult(T&& t)
     {
         result.push(InstResult(std::forward<T>(t),
                                InstResult::ResultType::Scalar));
     }

     template<typename T>
     void
     setVecResult(T&& t)
     {
         result.push(InstResult(std::forward<T>(t),
                                InstResult::ResultType::VecReg));
     }

     template<typename T>
     void
     setVecElemResult(T&& t)
     {
         result.push(InstResult(std::forward<T>(t),
                                InstResult::ResultType::VecElem));
     }

     template<typename T>
     void
     setVecPredResult(T&& t)
     {
         result.push(InstResult(std::forward<T>(t),
                                InstResult::ResultType::VecPredReg));
     }

     void
     setIntRegOperand(const StaticInst *si, int idx, RegVal val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isIntReg());
         thread->setIntReg(reg.index(), val);
         setScalarResult(val);
     }

     void
     setFloatRegOperandBits(const StaticInst *si, int idx, RegVal val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isFloatReg());
         thread->setFloatReg(reg.index(), val);
         setScalarResult(val);
     }

     void
     setCCRegOperand(const StaticInst *si, int idx, RegVal val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isCCReg());
         thread->setCCReg(reg.index(), val);
         setScalarResult((uint64_t)val);
     }

     void
     setVecRegOperand(const StaticInst *si, int idx,
                      const VecRegContainer& val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecReg());
         thread->setVecReg(reg, val);
         setVecResult(val);
     }

     void
     setVecElemOperand(const StaticInst *si, int idx,
                       const VecElem val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecElem());
         thread->setVecElem(reg, val);
         setVecElemResult(val);
     }

     void setVecPredRegOperand(const StaticInst *si, int idx,
                               const VecPredRegContainer& val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isVecPredReg());
         thread->setVecPredReg(reg, val);
         setVecPredResult(val);
     }

     bool readPredicate() const override { return thread->readPredicate(); }

     void
     setPredicate(bool val) override
     {
         thread->setPredicate(val);
     }

     TheISA::PCState pcState() const override { return thread->pcState(); }
     void
     pcState(const TheISA::PCState &val) override
     {
         DPRINTF(Checker, "Changing PC to %s, old PC %s.\n",
                          val, thread->pcState());
         thread->pcState(val);
     }
     Addr instAddr() { return thread->instAddr(); }
     Addr nextInstAddr() { return thread->nextInstAddr(); }
     MicroPC microPC() { return thread->microPC(); }
     //////////////////////////////////////////

     RegVal
     readMiscRegNoEffect(int misc_reg) const
     {
         return thread->readMiscRegNoEffect(misc_reg);
     }

     RegVal
     readMiscReg(int misc_reg) override
     {
         return thread->readMiscReg(misc_reg);
     }

     void
     setMiscRegNoEffect(int misc_reg, RegVal val)
     {
         DPRINTF(Checker, "Setting misc reg %d with no effect to check later\n",
                 misc_reg);
         miscRegIdxs.push(misc_reg);
         return thread->setMiscRegNoEffect(misc_reg, val);
     }

     void
     setMiscReg(int misc_reg, RegVal val) override
     {
         DPRINTF(Checker, "Setting misc reg %d with effect to check later\n",
                 misc_reg);
         miscRegIdxs.push(misc_reg);
         return thread->setMiscReg(misc_reg, val);
     }

     RegVal
     readMiscRegOperand(const StaticInst *si, int idx) override
     {
         const RegId& reg = si->srcRegIdx(idx);
         assert(reg.isMiscReg());
         return thread->readMiscReg(reg.index());
     }

     void
     setMiscRegOperand(const StaticInst *si, int idx, RegVal val) override
     {
         const RegId& reg = si->destRegIdx(idx);
         assert(reg.isMiscReg());
         return this->setMiscReg(reg.index(), val);
     }

 #if THE_ISA == MIPS_ISA
     RegVal
     readRegOtherThread(const RegId &misc_reg, ThreadID tid) override
     {
         panic("MIPS MT not defined for CheckerCPU.\n");
         return 0;
     }

     void
     setRegOtherThread(const RegId& misc_reg, RegVal val, ThreadID tid) override
     {
         panic("MIPS MT not defined for CheckerCPU.\n");
     }
 #endif

     /////////////////////////////////////////

     void
     recordPCChange(const TheISA::PCState &val)
     {
        changedPC = true;
        newPCState = val;
     }

     void
     demapPage(Addr vaddr, uint64_t asn) override
     {
         this->itb->demapPage(vaddr, asn);
         this->dtb->demapPage(vaddr, asn);
     }

     // monitor/mwait funtions
     void armMonitor(Addr address) override { BaseCPU::armMonitor(0, address); }
     bool mwait(PacketPtr pkt) override { return BaseCPU::mwait(0, pkt); }
     void mwaitAtomic(ThreadContext *tc) override
     { return BaseCPU::mwaitAtomic(0, tc, thread->dtb); }
     AddressMonitor *getAddrMonitor() override
     { return BaseCPU::getCpuAddrMonitor(0); }

     void
     demapInstPage(Addr vaddr, uint64_t asn)
     {
         this->itb->demapPage(vaddr, asn);
     }

     void
     demapDataPage(Addr vaddr, uint64_t asn)
     {
         this->dtb->demapPage(vaddr, asn);
     }

     Fault readMem(Addr addr, uint8_t *data, unsigned size,
                   Request::Flags flags) override;
     Fault writeMem(uint8_t *data, unsigned size, Addr addr,
                    Request::Flags flags, uint64_t *res) override;

     unsigned int
     readStCondFailures() const override {
         return thread->readStCondFailures();
     }

     void setStCondFailures(unsigned int sc_failures) override {}
     /////////////////////////////////////////////////////

     Fault hwrei() override { return thread->hwrei(); }
     bool simPalCheck(int palFunc) override
     { return thread->simPalCheck(palFunc); }
     void wakeup(ThreadID tid) override { }
     // Assume that the normal CPU's call to syscall was successful.
     // The checker's state would have already been updated by the syscall.
     void syscall(int64_t callnum, Fault *fault) override { }

     void
     handleError()
     {
         if (exitOnError)
             dumpAndExit();
     }

     bool checkFlags(const RequestPtr &unverified_req, Addr vAddr,
                     Addr pAddr, int flags);

     void dumpAndExit();

     ThreadContext *tcBase() override { return tc; }
     SimpleThread *threadBase() { return thread; }

     InstResult unverifiedResult;
     RequestPtr unverifiedReq;
     uint8_t *unverifiedMemData;

     bool changedPC;
     bool willChangePC;
     TheISA::PCState newPCState;
     bool exitOnError;
     bool updateOnError;
     bool warnOnlyOnLoadError;

     InstSeqNum youngestSN;
 };

 /**
  * Templated Checker class.  This Checker class is templated on the
  * DynInstPtr of the instruction type that will be verified.  Proper
  * template instantiations of the Checker must be placed at the bottom
  * of checker/cpu.cc.
  */
 template <class Impl>
 class Checker : public CheckerCPU
 {
   private:
     typedef typename Impl::DynInstPtr DynInstPtr;

   public:
     Checker(Params *p)
         : CheckerCPU(p), updateThisCycle(false), unverifiedInst(NULL)
     { }

     void switchOut();
     void takeOverFrom(BaseCPU *oldCPU);

     void advancePC(const Fault &fault);

     void verify(const DynInstPtr &inst);

     void validateInst(const DynInstPtr &inst);
     void validateExecution(const DynInstPtr &inst);
     void validateState();

     void copyResult(const DynInstPtr &inst, const InstResult& mismatch_val,
                     int start_idx);
     void handlePendingInt();

   private:
     void handleError(const DynInstPtr &inst)
     {
         if (exitOnError) {
             dumpAndExit(inst);
         } else if (updateOnError) {
             updateThisCycle = true;
         }
     }

     void dumpAndExit(const DynInstPtr &inst);

     bool updateThisCycle;

     DynInstPtr unverifiedInst;

     std::list<DynInstPtr> instList;
     typedef typename std::list<DynInstPtr>::iterator InstListIt;
     void dumpInsts();
 };

 #endif // __CPU_CHECKER_CPU_HH__
	/*
	* Copyright (c) 2011, 2016-2017 ARM Limited
	* Copyright (c) 2013 Advanced Micro Devices, Inc.
	* 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) 2006 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.
	*
	* Authors: Kevin Lim
	*/

	#ifndef __CPU_CHECKER_CPU_HH__
	#define __CPU_CHECKER_CPU_HH__

	#include <list>
	#include <map>
	#include <queue>

	#include "arch/types.hh"
	#include "base/statistics.hh"
	#include "cpu/base.hh"
	#include "cpu/base_dyn_inst.hh"
	#include "cpu/exec_context.hh"
	#include "cpu/inst_res.hh"
	#include "cpu/pc_event.hh"
	#include "cpu/simple_thread.hh"
	#include "cpu/static_inst.hh"
	#include "debug/Checker.hh"
	#include "mem/request.hh"
	#include "params/CheckerCPU.hh"
	#include "sim/eventq.hh"

	class BaseTLB;
	template <class>
	class BaseDynInst;
	class ThreadContext;
	class Request;

	/**
	* CheckerCPU class. Dynamically verifies instructions as they are
	* completed by making sure that the instruction and its results match
	* the independent execution of the benchmark inside the checker. The
	* checker verifies instructions in order, regardless of the order in
	* which instructions complete. There are certain results that can
	* not be verified, specifically the result of a store conditional or
	* the values of uncached accesses. In these cases, and with
	* instructions marked as "IsUnverifiable", the checker assumes that
	* the value from the main CPU's execution is correct and simply
	* copies that value. It provides a CheckerThreadContext (see
	* checker/thread_context.hh) that provides hooks for updating the
	* Checker's state through any ThreadContext accesses. This allows the
	* checker to be able to correctly verify instructions, even with
	* external accesses to the ThreadContext that change state.
	*/
	class CheckerCPU : public BaseCPU, public ExecContext
	{
	protected:
	typedef TheISA::MachInst MachInst;
	using VecRegContainer = TheISA::VecRegContainer;

	/** id attached to all issued requests */
	MasterID masterId;
	public:
	void init() override;

	typedef CheckerCPUParams Params;
	CheckerCPU(Params *p);
	virtual ~CheckerCPU();

	void setSystem(System *system);

	void setIcachePort(MasterPort *icache_port);

	void setDcachePort(MasterPort *dcache_port);

	MasterPort &getDataPort() override
	{
	// the checker does not have ports on its own so return the
	// data port of the actual CPU core
	assert(dcachePort);
	return *dcachePort;
	}

	MasterPort &getInstPort() override
	{
	// the checker does not have ports on its own so return the
	// data port of the actual CPU core
	assert(icachePort);
	return *icachePort;
	}

	protected:

	std::vector<Process*> workload;

	System *systemPtr;

	MasterPort *icachePort;
	MasterPort *dcachePort;

	ThreadContext *tc;

	BaseTLB *itb;
	BaseTLB *dtb;

	Addr dbg_vtophys(Addr addr);

	// ISAs like ARM can have multiple destination registers to check,
	// keep them all in a std::queue
	std::queue<InstResult> result;

	StaticInstPtr curStaticInst;
	StaticInstPtr curMacroStaticInst;

	// number of simulated instructions
	Counter numInst;
	Counter startNumInst;

	std::queue<int> miscRegIdxs;

	public:

	// Primary thread being run.
	SimpleThread *thread;

	BaseTLB* getITBPtr() { return itb; }
	BaseTLB* getDTBPtr() { return dtb; }

	virtual Counter totalInsts() const override
	{
	return 0;
	}

	virtual Counter totalOps() const override
	{
	return 0;
	}

	// number of simulated loads
	Counter numLoad;
	Counter startNumLoad;

	void serialize(CheckpointOut &cp) const override;
	void unserialize(CheckpointIn &cp) override;

	// The register accessor methods provide the index of the
	// instruction's operand (e.g., 0 or 1), not the architectural
	// register index, to simplify the implementation of register
	// renaming. We find the architectural register index by indexing
	// into the instruction's own operand index table. Note that a
	// raw pointer to the StaticInst is provided instead of a
	// ref-counted StaticInstPtr to redice overhead. This is fine as
	// long as these methods don't copy the pointer into any long-term
	// storage (which is pretty hard to imagine they would have reason
	// to do).

	RegVal
	readIntRegOperand(const StaticInst *si, int idx) override
	{
	const RegId& reg = si->srcRegIdx(idx);
	assert(reg.isIntReg());
	return thread->readIntReg(reg.index());
	}

	RegVal
	readFloatRegOperandBits(const StaticInst *si, int idx) override
	{
	const RegId& reg = si->srcRegIdx(idx);
	assert(reg.isFloatReg());
	return thread->readFloatReg(reg.index());
	}

	/**
	* Read source vector register operand.
	*/
	const VecRegContainer &
	readVecRegOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->srcRegIdx(idx);
	assert(reg.isVecReg());
	return thread->readVecReg(reg);
	}

	/**
	* Read destination vector register operand for modification.
	*/
	VecRegContainer &
	getWritableVecRegOperand(const StaticInst *si, int idx) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	return thread->getWritableVecReg(reg);
	}

	/** Vector Register Lane Interfaces. */
	/** @{ */
	/** Reads source vector 8bit operand. */
	virtual ConstVecLane8
	readVec8BitLaneOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	return thread->readVec8BitLaneReg(reg);
	}

	/** Reads source vector 16bit operand. */
	virtual ConstVecLane16
	readVec16BitLaneOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	return thread->readVec16BitLaneReg(reg);
	}

	/** Reads source vector 32bit operand. */
	virtual ConstVecLane32
	readVec32BitLaneOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	return thread->readVec32BitLaneReg(reg);
	}

	/** Reads source vector 64bit operand. */
	virtual ConstVecLane64
	readVec64BitLaneOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	return thread->readVec64BitLaneReg(reg);
	}

	/** Write a lane of the destination vector operand. */
	template <typename LD>
	void
	setVecLaneOperandT(const StaticInst *si, int idx, const LD& val)
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	return thread->setVecLane(reg, val);
	}
	virtual void
	setVecLaneOperand(const StaticInst *si, int idx,
	const LaneData<LaneSize::Byte>& val) override
	{
	setVecLaneOperandT(si, idx, val);
	}
	virtual void
	setVecLaneOperand(const StaticInst *si, int idx,
	const LaneData<LaneSize::TwoByte>& val) override
	{
	setVecLaneOperandT(si, idx, val);
	}
	virtual void
	setVecLaneOperand(const StaticInst *si, int idx,
	const LaneData<LaneSize::FourByte>& val) override
	{
	setVecLaneOperandT(si, idx, val);
	}
	virtual void
	setVecLaneOperand(const StaticInst *si, int idx,
	const LaneData<LaneSize::EightByte>& val) override
	{
	setVecLaneOperandT(si, idx, val);
	}
	/** @} */

	VecElem
	readVecElemOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->srcRegIdx(idx);
	return thread->readVecElem(reg);
	}

	const VecPredRegContainer&
	readVecPredRegOperand(const StaticInst *si, int idx) const override
	{
	const RegId& reg = si->srcRegIdx(idx);
	assert(reg.isVecPredReg());
	return thread->readVecPredReg(reg);
	}

	VecPredRegContainer&
	getWritableVecPredRegOperand(const StaticInst *si, int idx) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecPredReg());
	return thread->getWritableVecPredReg(reg);
	}

	RegVal
	readCCRegOperand(const StaticInst *si, int idx) override
	{
	const RegId& reg = si->srcRegIdx(idx);
	assert(reg.isCCReg());
	return thread->readCCReg(reg.index());
	}

	template<typename T>
	void
	setScalarResult(T&& t)
	{
	result.push(InstResult(std::forward<T>(t),
	InstResult::ResultType::Scalar));
	}

	template<typename T>
	void
	setVecResult(T&& t)
	{
	result.push(InstResult(std::forward<T>(t),
	InstResult::ResultType::VecReg));
	}

	template<typename T>
	void
	setVecElemResult(T&& t)
	{
	result.push(InstResult(std::forward<T>(t),
	InstResult::ResultType::VecElem));
	}

	template<typename T>
	void
	setVecPredResult(T&& t)
	{
	result.push(InstResult(std::forward<T>(t),
	InstResult::ResultType::VecPredReg));
	}

	void
	setIntRegOperand(const StaticInst *si, int idx, RegVal val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isIntReg());
	thread->setIntReg(reg.index(), val);
	setScalarResult(val);
	}

	void
	setFloatRegOperandBits(const StaticInst *si, int idx, RegVal val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isFloatReg());
	thread->setFloatReg(reg.index(), val);
	setScalarResult(val);
	}

	void
	setCCRegOperand(const StaticInst *si, int idx, RegVal val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isCCReg());
	thread->setCCReg(reg.index(), val);
	setScalarResult((uint64_t)val);
	}

	void
	setVecRegOperand(const StaticInst *si, int idx,
	const VecRegContainer& val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecReg());
	thread->setVecReg(reg, val);
	setVecResult(val);
	}

	void
	setVecElemOperand(const StaticInst *si, int idx,
	const VecElem val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecElem());
	thread->setVecElem(reg, val);
	setVecElemResult(val);
	}

	void setVecPredRegOperand(const StaticInst *si, int idx,
	const VecPredRegContainer& val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isVecPredReg());
	thread->setVecPredReg(reg, val);
	setVecPredResult(val);
	}

	bool readPredicate() const override { return thread->readPredicate(); }

	void
	setPredicate(bool val) override
	{
	thread->setPredicate(val);
	}

	TheISA::PCState pcState() const override { return thread->pcState(); }
	void
	pcState(const TheISA::PCState &val) override
	{
	DPRINTF(Checker, "Changing PC to %s, old PC %s.\n",
	val, thread->pcState());
	thread->pcState(val);
	}
	Addr instAddr() { return thread->instAddr(); }
	Addr nextInstAddr() { return thread->nextInstAddr(); }
	MicroPC microPC() { return thread->microPC(); }
	//////////////////////////////////////////

	RegVal
	readMiscRegNoEffect(int misc_reg) const
	{
	return thread->readMiscRegNoEffect(misc_reg);
	}

	RegVal
	readMiscReg(int misc_reg) override
	{
	return thread->readMiscReg(misc_reg);
	}

	void
	setMiscRegNoEffect(int misc_reg, RegVal val)
	{
	DPRINTF(Checker, "Setting misc reg %d with no effect to check later\n",
	misc_reg);
	miscRegIdxs.push(misc_reg);
	return thread->setMiscRegNoEffect(misc_reg, val);
	}

	void
	setMiscReg(int misc_reg, RegVal val) override
	{
	DPRINTF(Checker, "Setting misc reg %d with effect to check later\n",
	misc_reg);
	miscRegIdxs.push(misc_reg);
	return thread->setMiscReg(misc_reg, val);
	}

	RegVal
	readMiscRegOperand(const StaticInst *si, int idx) override
	{
	const RegId& reg = si->srcRegIdx(idx);
	assert(reg.isMiscReg());
	return thread->readMiscReg(reg.index());
	}

	void
	setMiscRegOperand(const StaticInst *si, int idx, RegVal val) override
	{
	const RegId& reg = si->destRegIdx(idx);
	assert(reg.isMiscReg());
	return this->setMiscReg(reg.index(), val);
	}

	#if THE_ISA == MIPS_ISA
	RegVal
	readRegOtherThread(const RegId &misc_reg, ThreadID tid) override
	{
	panic("MIPS MT not defined for CheckerCPU.\n");
	return 0;
	}

	void
	setRegOtherThread(const RegId& misc_reg, RegVal val, ThreadID tid) override
	{
	panic("MIPS MT not defined for CheckerCPU.\n");
	}
	#endif

	/////////////////////////////////////////

	void
	recordPCChange(const TheISA::PCState &val)
	{
	changedPC = true;
	newPCState = val;
	}

	void
	demapPage(Addr vaddr, uint64_t asn) override
	{
	this->itb->demapPage(vaddr, asn);
	this->dtb->demapPage(vaddr, asn);
	}

	// monitor/mwait funtions
	void armMonitor(Addr address) override { BaseCPU::armMonitor(0, address); }
	bool mwait(PacketPtr pkt) override { return BaseCPU::mwait(0, pkt); }
	void mwaitAtomic(ThreadContext *tc) override
	{ return BaseCPU::mwaitAtomic(0, tc, thread->dtb); }
	AddressMonitor *getAddrMonitor() override
	{ return BaseCPU::getCpuAddrMonitor(0); }

	void
	demapInstPage(Addr vaddr, uint64_t asn)
	{
	this->itb->demapPage(vaddr, asn);
	}

	void
	demapDataPage(Addr vaddr, uint64_t asn)
	{
	this->dtb->demapPage(vaddr, asn);
	}

	Fault readMem(Addr addr, uint8_t *data, unsigned size,
	Request::Flags flags) override;
	Fault writeMem(uint8_t *data, unsigned size, Addr addr,
	Request::Flags flags, uint64_t *res) override;

	unsigned int
	readStCondFailures() const override {
	return thread->readStCondFailures();
	}

	void setStCondFailures(unsigned int sc_failures) override {}
	/////////////////////////////////////////////////////

	Fault hwrei() override { return thread->hwrei(); }
	bool simPalCheck(int palFunc) override
	{ return thread->simPalCheck(palFunc); }
	void wakeup(ThreadID tid) override { }
	// Assume that the normal CPU's call to syscall was successful.
	// The checker's state would have already been updated by the syscall.
	void syscall(int64_t callnum, Fault *fault) override { }

	void
	handleError()
	{
	if (exitOnError)
	dumpAndExit();
	}

	bool checkFlags(const RequestPtr &unverified_req, Addr vAddr,
	Addr pAddr, int flags);

	void dumpAndExit();

	ThreadContext *tcBase() override { return tc; }
	SimpleThread *threadBase() { return thread; }

	InstResult unverifiedResult;
	RequestPtr unverifiedReq;
	uint8_t *unverifiedMemData;

	bool changedPC;
	bool willChangePC;
	TheISA::PCState newPCState;
	bool exitOnError;
	bool updateOnError;
	bool warnOnlyOnLoadError;

	InstSeqNum youngestSN;
	};

	/**
	* Templated Checker class. This Checker class is templated on the
	* DynInstPtr of the instruction type that will be verified. Proper
	* template instantiations of the Checker must be placed at the bottom
	* of checker/cpu.cc.
	*/
	template <class Impl>
	class Checker : public CheckerCPU
	{
	private:
	typedef typename Impl::DynInstPtr DynInstPtr;

	public:
	Checker(Params *p)
	: CheckerCPU(p), updateThisCycle(false), unverifiedInst(NULL)
	{ }

	void switchOut();
	void takeOverFrom(BaseCPU *oldCPU);

	void advancePC(const Fault &fault);

	void verify(const DynInstPtr &inst);

	void validateInst(const DynInstPtr &inst);
	void validateExecution(const DynInstPtr &inst);
	void validateState();

	void copyResult(const DynInstPtr &inst, const InstResult& mismatch_val,
	int start_idx);
	void handlePendingInt();

	private:
	void handleError(const DynInstPtr &inst)
	{
	if (exitOnError) {
	dumpAndExit(inst);
	} else if (updateOnError) {
	updateThisCycle = true;
	}
	}

	void dumpAndExit(const DynInstPtr &inst);

	bool updateThisCycle;

	DynInstPtr unverifiedInst;

	std::list<DynInstPtr> instList;
	typedef typename std::list<DynInstPtr>::iterator InstListIt;
	void dumpInsts();
	};

	#endif // __CPU_CHECKER_CPU_HH__