abstract_mem.hh

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#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"
 
namespace gem5
{
 
class System;
 
namespace memory
{
 
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;
 
    // Are writes allowed to this memory
    const bool writeable;
 
    // Should collect traffic statistics
    const bool collectStats;
 
    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 (!writeable)
            return false;
        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 statistics::Group
    {
        MemStats(AbstractMemory &mem);
 
        void regStats() override;
 
        const AbstractMemory &mem;
 
        statistics::Vector bytesRead;
        statistics::Vector bytesInstRead;
        statistics::Vector bytesWritten;
        statistics::Vector numReads;
        statistics::Vector numWrites;
        statistics::Vector numOther;
        statistics::Formula bwRead;
        statistics::Formula bwInstRead;
        statistics::Formula bwWrite;
        statistics::Formula bwTotal;
    } stats;
 
 
  private:
 
    // Prevent copying
    AbstractMemory(const AbstractMemory&);
 
    // Prevent assignment
    AbstractMemory& operator=(const AbstractMemory&);
 
  public:
 
    PARAMS(AbstractMemory);
 
    AbstractMemory(const Params &p);
    virtual ~AbstractMemory() {}
 
    void initState() override;
 
    bool isNull() const { return params().null; }
 
    void setBackingStore(uint8_t* pmem_addr);
 
    void
    getBackdoor(MemBackdoorPtr &bd_ptr)
    {
        if (lockedAddrList.empty() && backdoor.ptr())
            bd_ptr = &backdoor;
    }
 
    const std::list<LockedAddr> &
    getLockedAddrList() const
    {
        return lockedAddrList;
    }
 
    void
    addLockedAddr(LockedAddr addr)
    {
        backdoor.invalidate();
        lockedAddrList.push_back(addr);
    }
 
    System* system() const { return _system; }
 
    void system(System *sys) { _system = sys; }
 
    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);
};
 
} // namespace memory
} // namespace gem5
 
#endif //__MEM_ABSTRACT_MEMORY_HH__