mshr.hh

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#ifndef __MEM_CACHE_MSHR_HH__
#define __MEM_CACHE_MSHR_HH__
 
#include <cassert>
#include <iosfwd>
#include <list>
#include <string>
#include <vector>
 
#include "base/printable.hh"
#include "base/trace.hh"
#include "base/types.hh"
#include "debug/MSHR.hh"
#include "mem/cache/queue_entry.hh"
#include "mem/packet.hh"
#include "mem/request.hh"
#include "sim/cur_tick.hh"
 
namespace gem5
{
 
class BaseCache;
 
class MSHR : public QueueEntry, public Printable
{
 
    template<typename Entry>
    friend class Queue;
    friend class MSHRQueue;
 
  private:
 
    bool downstreamPending;
 
    bool pendingModified;
 
    bool postInvalidate;
 
    bool postDowngrade;
 
  public:
 
    bool wasWholeLineWrite;
 
    bool isForward;
 
    class Target : public QueueEntry::Target
    {
      public:
 
        enum Source
        {
            FromCPU,
            FromSnoop,
            FromPrefetcher
        };
 
        const Source source;  
 
        bool markedPending;
 
        const bool allocOnFill;   
 
        Target(PacketPtr _pkt, Tick _readyTime, Counter _order,
               Source _source, bool _markedPending, bool alloc_on_fill)
            : QueueEntry::Target(_pkt, _readyTime, _order), source(_source),
              markedPending(_markedPending), allocOnFill(alloc_on_fill)
        {}
    };
 
    class TargetList : public std::list<Target>, public Named
    {
 
      public:
        bool needsWritable;
        bool hasUpgrade;
        bool allocOnFill;
        bool hasFromCache;
 
        TargetList(const std::string &name = ".unnamedTargetList");
 
        void updateFlags(PacketPtr pkt, Target::Source source,
                         bool alloc_on_fill);
 
        void init(Addr blk_addr, Addr blk_size) {
            blkAddr = blk_addr;
            blkSize = blk_size;
            writesBitmap.resize(blk_size);
 
            resetFlags();
        }
 
        void resetFlags() {
            canMergeWrites = true;
            std::fill(writesBitmap.begin(), writesBitmap.end(), false);
 
            needsWritable = false;
            hasUpgrade = false;
            allocOnFill = false;
            hasFromCache = false;
        }
 
        void populateFlags();
 
        void updateWriteFlags(PacketPtr pkt);
 
        bool isReset() const {
            return !needsWritable && !hasUpgrade && !allocOnFill &&
                !hasFromCache && canMergeWrites;
        }
 
        void add(PacketPtr pkt, Tick readyTime, Counter order,
                 Target::Source source, bool markPending, bool alloc_on_fill);
 
        void replaceUpgrades();
 
        void clearDownstreamPending();
        void clearDownstreamPending(iterator begin, iterator end);
        bool trySatisfyFunctional(PacketPtr pkt);
        void print(std::ostream &os, int verbosity,
                   const std::string &prefix) const;
 
        bool isWholeLineWrite() const
        {
            return std::all_of(writesBitmap.begin(), writesBitmap.end(),
                               [](bool i) { return i; });
        }
 
      private:
        Addr blkAddr;
 
        Addr blkSize;
 
        bool canMergeWrites;
 
        // NOTE: std::vector<bool> might not meet satisfy the
        // ForwardIterator requirement and therefore cannot be used
        // for writesBitmap.
        std::vector<char> writesBitmap;
    };
 
    typedef std::list<MSHR *> List;
    typedef List::iterator Iterator;
 
    bool needsWritable() const { return targets.needsWritable; }
 
    bool isCleaning() const {
        PacketPtr pkt = targets.front().pkt;
        return pkt->isClean();
    }
 
    bool isPendingModified() const {
        assert(inService); return pendingModified;
    }
 
    bool hasPostInvalidate() const {
        assert(inService); return postInvalidate;
    }
 
    bool hasPostDowngrade() const {
        assert(inService); return postDowngrade;
    }
 
    bool sendPacket(BaseCache &cache) override;
 
    bool allocOnFill() const {
        return targets.allocOnFill;
    }
 
    bool hasFromCache() const {
        return targets.hasFromCache;
    }
 
    void updateLockedRMWReadTarget(PacketPtr pkt);
 
    bool hasLockedRMWReadTarget();
 
  private:
    void promoteIf(const std::function<bool (Target &)>& pred);
 
    Iterator readyIter;
 
    Iterator allocIter;
 
    TargetList targets;
 
    TargetList deferredTargets;
 
  public:
    bool isWholeLineWrite() const {
        return targets.isWholeLineWrite();
    }
 
    void allocate(Addr blk_addr, unsigned blk_size, PacketPtr pkt,
                  Tick when_ready, Counter _order, bool alloc_on_fill);
 
    void markInService(bool pending_modified_resp);
 
    void clearDownstreamPending();
 
    void deallocate();
 
    void allocateTarget(PacketPtr target, Tick when, Counter order,
                        bool alloc_on_fill);
    bool handleSnoop(PacketPtr target, Counter order);
 
    MSHR(const std::string &name);
 
    int getNumTargets() const
    { return targets.size() + deferredTargets.size(); }
 
    TargetList extractServiceableTargets(PacketPtr pkt);
 
    bool hasTargets() const { return !targets.empty(); }
 
    QueueEntry::Target *getTarget() override
    {
        assert(hasTargets());
        return &targets.front();
    }
 
    void popTarget()
    {
        DPRINTF(MSHR, "Force deallocating MSHR targets: %s\n",
                targets.front().pkt->print());
        targets.pop_front();
    }
 
    bool promoteDeferredTargets();
 
    void promoteReadable();
 
    void promoteWritable();
 
    bool trySatisfyFunctional(PacketPtr pkt);
 
    void delay(Tick delay_ticks)
    {
        assert(readyTime <= curTick());
        readyTime = curTick() + delay_ticks;
    }
 
    void print(std::ostream &os,
               int verbosity = 0,
               const std::string &prefix = "") const override;
    std::string print() const;
 
    bool matchBlockAddr(const Addr addr, const bool is_secure) const override;
    bool matchBlockAddr(const PacketPtr pkt) const override;
    bool conflictAddr(const QueueEntry* entry) const override;
};
 
} // namespace gem5
 
#endif // __MEM_CACHE_MSHR_HH__