src/cpu/minor/cpu.hh

   1 /*
   2  * Copyright (c) 2012-2014 ARM Limited
   3  * All rights reserved
   4  *
   5  * The license below extends only to copyright in the software and shall
   6  * not be construed as granting a license to any other intellectual
   7  * property including but not limited to intellectual property relating
   8  * to a hardware implementation of the functionality of the software
   9  * licensed hereunder.  You may use the software subject to the license
  10  * terms below provided that you ensure that this notice is replicated
  11  * unmodified and in its entirety in all distributions of the software,
  12  * modified or unmodified, in source code or in binary form.
  13  *
  14  * Redistribution and use in source and binary forms, with or without
  15  * modification, are permitted provided that the following conditions are
  16  * met: redistributions of source code must retain the above copyright
  17  * notice, this list of conditions and the following disclaimer;
  18  * redistributions in binary form must reproduce the above copyright
  19  * notice, this list of conditions and the following disclaimer in the
  20  * documentation and/or other materials provided with the distribution;
  21  * neither the name of the copyright holders nor the names of its
  22  * contributors may be used to endorse or promote products derived from
  23  * this software without specific prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  30  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  31  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  32  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  33  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  34  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  35  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  36  *
  37  * Authors: Andrew Bardsley
  38  */
  39
  40 /**
  41  * @file
  42  *
  43  *  Top level definition of the Minor in-order CPU model
  44  */
  45
  46 #ifndef __CPU_MINOR_CPU_HH__
  47 #define __CPU_MINOR_CPU_HH__
  48
  49 #include "cpu/minor/activity.hh"
  50 #include "cpu/minor/stats.hh"
  51 #include "cpu/base.hh"
  52 #include "cpu/simple_thread.hh"
  53 #include "enums/ThreadPolicy.hh"
  54 #include "params/MinorCPU.hh"
  55
  56 namespace Minor
  57 {
  58 /** Forward declared to break the cyclic inclusion dependencies between
  59  *  pipeline and cpu */
  60 class Pipeline;
  61
  62 /** Minor will use the SimpleThread state for now */
  63 typedef SimpleThread MinorThread;
  64 };
  65
  66 /**
  67  *  MinorCPU is an in-order CPU model with four fixed pipeline stages:
  68  *
  69  *  Fetch1 - fetches lines from memory
  70  *  Fetch2 - decomposes lines into macro-op instructions
  71  *  Decode - decomposes macro-ops into micro-ops
  72  *  Execute - executes those micro-ops
  73  *
  74  *  This pipeline is carried in the MinorCPU::pipeline object.
  75  *  The exec_context interface is not carried by MinorCPU but by
  76  *      Minor::ExecContext objects
  77  *  created by Minor::Execute.
  78  */
  79 class MinorCPU : public BaseCPU
  80 {
  81   protected:
  82     /** pipeline is a container for the clockable pipeline stage objects.
  83      *  Elements of pipeline call TheISA to implement the model. */
  84     Minor::Pipeline *pipeline;
  85
  86     /** An event that wakes up the pipeline when a thread context is
  87      * activated */
  88     EventFunctionWrapper pipelineStartupEvent;
  89
  90     /** List of threads that are ready to wake up and run */
  91     std::vector<ThreadID> readyThreads;
  92
  93   public:
  94     /** Activity recording for pipeline.  This belongs to Pipeline but
  95      *  stages will access it through the CPU as the MinorCPU object
  96      *  actually mediates idling behaviour */
  97     Minor::MinorActivityRecorder *activityRecorder;
  98
  99     /** These are thread state-representing objects for this CPU.  If
 100      *  you need a ThreadContext for *any* reason, use
 101      *  threads[threadId]->getTC() */
 102     std::vector<Minor::MinorThread *> threads;
 103
 104   public:
 105     /** Provide a non-protected base class for Minor's Ports as derived
 106      *  classes are created by Fetch1 and Execute */
 107     class MinorCPUPort : public MasterPort
 108     {
 109       public:
 110         /** The enclosing cpu */
 111         MinorCPU &cpu;
 112
 113       public:
 114         MinorCPUPort(const std::string& name_, MinorCPU &cpu_)
 115             : MasterPort(name_, &cpu_), cpu(cpu_)
 116         { }
 117
 118     };
 119
 120     /** Thread Scheduling Policy (RoundRobin, Random, etc) */
 121     Enums::ThreadPolicy threadPolicy;
 122   protected:
 123      /** Return a reference to the data port. */
 124     MasterPort &getDataPort() override;
 125
 126     /** Return a reference to the instruction port. */
 127     MasterPort &getInstPort() override;
 128
 129   public:
 130     MinorCPU(MinorCPUParams *params);
 131
 132     ~MinorCPU();
 133
 134   public:
 135     /** Starting, waking and initialisation */
 136     void init() override;
 137     void startup() override;
 138     void wakeup(ThreadID tid) override;
 139
 140     Addr dbg_vtophys(Addr addr);
 141
 142     /** Processor-specific statistics */
 143     Minor::MinorStats stats;
 144
 145     /** Stats interface from SimObject (by way of BaseCPU) */
 146     void regStats() override;
 147
 148     /** Simple inst count interface from BaseCPU */
 149     Counter totalInsts() const override;
 150     Counter totalOps() const override;
 151
 152     void serializeThread(CheckpointOut &cp, ThreadID tid) const override;
 153     void unserializeThread(CheckpointIn &cp, ThreadID tid) override;
 154
 155     /** Serialize pipeline data */
 156     void serialize(CheckpointOut &cp) const override;
 157     void unserialize(CheckpointIn &cp) override;
 158
 159     /** Drain interface */
 160     DrainState drain() override;
 161     void drainResume() override;
 162     /** Signal from Pipeline that MinorCPU should signal that a drain
 163      *  is complete and set its drainState */
 164     void signalDrainDone();
 165     void memWriteback() override;
 166
 167     /** Switching interface from BaseCPU */
 168     void switchOut() override;
 169     void takeOverFrom(BaseCPU *old_cpu) override;
 170
 171     /** Thread activation interface from BaseCPU. */
 172     void activateContext(ThreadID thread_id) override;
 173     void suspendContext(ThreadID thread_id) override;
 174
 175     /** Wake up ready-to-run threads */
 176     void wakeupPipeline();
 177
 178     /** Thread scheduling utility functions */
 179     std::vector<ThreadID> roundRobinPriority(ThreadID priority)
 180     {
 181         std::vector<ThreadID> prio_list;
 182         for (ThreadID i = 1; i <= numThreads; i++) {
 183             prio_list.push_back((priority + i) % numThreads);
 184         }
 185         return prio_list;
 186     }
 187
 188     std::vector<ThreadID> randomPriority()
 189     {
 190         std::vector<ThreadID> prio_list;
 191         for (ThreadID i = 0; i < numThreads; i++) {
 192             prio_list.push_back(i);
 193         }
 194         std::random_shuffle(prio_list.begin(), prio_list.end());
 195         return prio_list;
 196     }
 197
 198     /** Interface for stages to signal that they have become active after
 199      *  a callback or eventq event where the pipeline itself may have
 200      *  already been idled.  The stage argument should be from the
 201      *  enumeration Pipeline::StageId */
 202     void wakeupOnEvent(unsigned int stage_id);
 203 };
 204
 205 #endif /* __CPU_MINOR_CPU_HH__ */