atomic.hh

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/*
 * Copyright (c) 2012-2013, 2015, 2018 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) 2002-2005 The Regents of The University of Michigan
 * All rights reserved.
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 * 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;
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 * neither the name of the copyright holders nor the names of its
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 * this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * Authors: Steve Reinhardt
 */

#ifndef __CPU_SIMPLE_ATOMIC_HH__
#define __CPU_SIMPLE_ATOMIC_HH__

#include "cpu/simple/base.hh"
#include "cpu/simple/exec_context.hh"
#include "mem/request.hh"
#include "params/AtomicSimpleCPU.hh"
#include "sim/probe/probe.hh"

class AtomicSimpleCPU : public BaseSimpleCPU
{
  public:

    AtomicSimpleCPU(AtomicSimpleCPUParams *params);
    virtual ~AtomicSimpleCPU();

    void init() override;

  protected:

    EventFunctionWrapper tickEvent;

    const int width;
    bool locked;
    const bool simulate_data_stalls;
    const bool simulate_inst_stalls;

    // main simulation loop (one cycle)
    void tick();

    bool isCpuDrained() const {
        SimpleExecContext &t_info = *threadInfo[curThread];

        return t_info.thread->microPC() == 0 &&
            !locked &&
            !t_info.stayAtPC;
    }

    bool tryCompleteDrain();

    virtual Tick sendPacket(MasterPort &port, const PacketPtr &pkt);

    class AtomicCPUPort : public MasterPort
    {

      public:

        AtomicCPUPort(const std::string &_name, BaseSimpleCPU* _cpu)
            : MasterPort(_name, _cpu)
        { }

      protected:

        bool recvTimingResp(PacketPtr pkt)
        {
            panic("Atomic CPU doesn't expect recvTimingResp!\n");
            return true;
        }

        void recvReqRetry()
        {
            panic("Atomic CPU doesn't expect recvRetry!\n");
        }

    };

    class AtomicCPUDPort : public AtomicCPUPort
    {

      public:
        AtomicCPUDPort(const std::string &_name, BaseSimpleCPU* _cpu)
            : AtomicCPUPort(_name, _cpu), cpu(_cpu)
        {
            cacheBlockMask = ~(cpu->cacheLineSize() - 1);
        }

        bool isSnooping() const { return true; }

        Addr cacheBlockMask;
      protected:
        BaseSimpleCPU *cpu;

        virtual Tick recvAtomicSnoop(PacketPtr pkt);
        virtual void recvFunctionalSnoop(PacketPtr pkt);
    };


    AtomicCPUPort icachePort;
    AtomicCPUDPort dcachePort;


    RequestPtr ifetch_req;
    RequestPtr data_read_req;
    RequestPtr data_write_req;
    RequestPtr data_amo_req;

    bool dcache_access;
    Tick dcache_latency;

    ProbePointArg<std::pair<SimpleThread*, const StaticInstPtr>> *ppCommit;

  protected:

    Port &getDataPort() override { return dcachePort; }

    Port &getInstPort() override { return icachePort; }

    void threadSnoop(PacketPtr pkt, ThreadID sender);

  public:

    DrainState drain() override;
    void drainResume() override;

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

    void verifyMemoryMode() const override;

    void activateContext(ThreadID thread_num) override;
    void suspendContext(ThreadID thread_num) override;

    bool genMemFragmentRequest(const RequestPtr& req, Addr frag_addr,
                               int size, Request::Flags flags,
                               const std::vector<bool>& byte_enable,
                               int& frag_size, int& size_left) const;

    Fault readMem(Addr addr, uint8_t *data, unsigned size,
                  Request::Flags flags,
                  const std::vector<bool>& byte_enable = std::vector<bool>())
        override;

    Fault writeMem(uint8_t *data, unsigned size,
                   Addr addr, Request::Flags flags, uint64_t *res,
                   const std::vector<bool>& byte_enable = std::vector<bool>())
        override;

    Fault amoMem(Addr addr, uint8_t* data, unsigned size,
                 Request::Flags flags, AtomicOpFunctorPtr amo_op) override;

    void regProbePoints() override;

    void printAddr(Addr a);
};

#endif // __CPU_SIMPLE_ATOMIC_HH__