abstract_mem.hh

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 * 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
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 * Copyright (c) 2001-2005 The Regents of The University of Michigan
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 * met: redistributions of source code must retain the above copyright
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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 * Authors: Ron Dreslinski
 *          Andreas Hansson
 */

#ifndef __MEM_ABSTRACT_MEMORY_HH__
#define __MEM_ABSTRACT_MEMORY_HH__

#include "mem/backdoor.hh"
#include "mem/port.hh"
#include "params/AbstractMemory.hh"
#include "sim/clocked_object.hh"
#include "sim/stats.hh"


class System;

class LockedAddr {

  private:

    // on alpha, minimum LL/SC granularity is 16 bytes, so lower
    // bits need to masked off.
    static const Addr Addr_Mask = 0xf;

  public:

    // locked address
    Addr addr;

    // locking hw context
    const ContextID contextId;

    static Addr mask(Addr paddr) { return (paddr & ~Addr_Mask); }

    // check for matching execution context
    bool matchesContext(const RequestPtr &req) const
    {
        assert(contextId != InvalidContextID);
        assert(req->hasContextId());
        return (contextId == req->contextId());
    }

    LockedAddr(const RequestPtr &req) : addr(mask(req->getPaddr())),
                                        contextId(req->contextId())
    {}

    // constructor for unserialization use
    LockedAddr(Addr _addr, int _cid) : addr(_addr), contextId(_cid)
    {}
};

class AbstractMemory : public ClockedObject
{
  protected:

    // Address range of this memory
    AddrRange range;

    // Pointer to host memory used to implement this memory
    uint8_t* pmemAddr;

    // Backdoor to access this memory.
    MemBackdoor backdoor;

    // Enable specific memories to be reported to the configuration table
    const bool confTableReported;

    // Should the memory appear in the global address map
    const bool inAddrMap;

    // Should KVM map this memory for the guest
    const bool kvmMap;

    std::list<LockedAddr> lockedAddrList;

    // helper function for checkLockedAddrs(): we really want to
    // inline a quick check for an empty locked addr list (hopefully
    // the common case), and do the full list search (if necessary) in
    // this out-of-line function
    bool checkLockedAddrList(PacketPtr pkt);

    // Record the address of a load-locked operation so that we can
    // clear the execution context's lock flag if a matching store is
    // performed
    void trackLoadLocked(PacketPtr pkt);

    // Compare a store address with any locked addresses so we can
    // clear the lock flag appropriately.  Return value set to 'false'
    // if store operation should be suppressed (because it was a
    // conditional store and the address was no longer locked by the
    // requesting execution context), 'true' otherwise.  Note that
    // this method must be called on *all* stores since even
    // non-conditional stores must clear any matching lock addresses.
    bool writeOK(PacketPtr pkt) {
        const RequestPtr &req = pkt->req;
        if (lockedAddrList.empty()) {
            // no locked addrs: nothing to check, store_conditional fails
            bool isLLSC = pkt->isLLSC();
            if (isLLSC) {
                req->setExtraData(0);
            }
            return !isLLSC; // only do write if not an sc
        } else {
            // iterate over list...
            return checkLockedAddrList(pkt);
        }
    }

    System *_system;

    struct MemStats : public Stats::Group {
        MemStats(AbstractMemory &mem);

        void regStats() override;

        const AbstractMemory &mem;

        Stats::Vector bytesRead;
        Stats::Vector bytesInstRead;
        Stats::Vector bytesWritten;
        Stats::Vector numReads;
        Stats::Vector numWrites;
        Stats::Vector numOther;
        Stats::Formula bwRead;
        Stats::Formula bwInstRead;
        Stats::Formula bwWrite;
        Stats::Formula bwTotal;
    } stats;


  private:

    // Prevent copying
    AbstractMemory(const AbstractMemory&);

    // Prevent assignment
    AbstractMemory& operator=(const AbstractMemory&);

  public:

    typedef AbstractMemoryParams Params;

    AbstractMemory(const Params* p);
    virtual ~AbstractMemory() {}

    void init() override;

    bool isNull() const { return params()->null; }

    void setBackingStore(uint8_t* pmem_addr);

    const std::list<LockedAddr>& getLockedAddrList() const
    { return lockedAddrList; }

    void addLockedAddr(LockedAddr addr) { lockedAddrList.push_back(addr); }

    System* system() const { return _system; }

    void system(System *sys) { _system = sys; }

    const Params *
    params() const
    {
        return dynamic_cast<const Params *>(_params);
    }

    AddrRange getAddrRange() const;

    inline uint8_t *
    toHostAddr(Addr addr) const
    {
        return pmemAddr + addr - range.start();
    }

    uint64_t size() const { return range.size(); }

    Addr start() const { return range.start(); }

    bool isConfReported() const { return confTableReported; }

    bool isInAddrMap() const { return inAddrMap; }

    bool isKvmMap() const { return kvmMap; }

    void access(PacketPtr pkt);

    void functionalAccess(PacketPtr pkt);
};

#endif //__MEM_ABSTRACT_MEMORY_HH__