xref: /gem5/src/arch/alpha/tlb.hh

/*
 * Copyright (c) 2001-2005 The Regents of The University of Michigan
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * 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;
 * redistributions in binary form must reproduce the above copyright
 * notice, this list of conditions and the following disclaimer in the
 * documentation and/or other materials provided with the distribution;
 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Nathan Binkert
 *          Steve Reinhardt
 */

#ifndef __ALPHA_MEMORY_HH__
#define __ALPHA_MEMORY_HH__

#include <map>

#include "arch/alpha/ev5.hh"
#include "arch/alpha/isa_traits.hh"
#include "arch/alpha/pagetable.hh"
#include "arch/alpha/utility.hh"
#include "arch/alpha/vtophys.hh"
#include "base/statistics.hh"
#include "mem/request.hh"
#include "sim/faults.hh"
#include "sim/sim_object.hh"

class ThreadContext;

namespace AlphaISA
{
    class TlbEntry;

    class TLB : public SimObject
    {
      protected:
        typedef std::multimap<Addr, int> PageTable;
        PageTable lookupTable;  // Quick lookup into page table

        TlbEntry *table;        // the Page Table
        int size;               // TLB Size
        int nlu;                // not last used entry (for replacement)

        void nextnlu() { if (++nlu >= size) nlu = 0; }
        TlbEntry *lookup(Addr vpn, uint8_t asn);

      public:
        TLB(const std::string &name, int size);
        virtual ~TLB();

        int getsize() const { return size; }

        TlbEntry &index(bool advance = true);
        void insert(Addr vaddr, TlbEntry &entry);

        void flushAll();
        void flushProcesses();
        void flushAddr(Addr addr, uint8_t asn);

        // static helper functions... really EV5 VM traits
        static bool validVirtualAddress(Addr vaddr) {
            // unimplemented bits must be all 0 or all 1
            Addr unimplBits = vaddr & EV5::VAddrUnImplMask;
            return (unimplBits == 0) || (unimplBits == EV5::VAddrUnImplMask);
        }

        static Fault checkCacheability(RequestPtr &req);

        // Checkpointing
        virtual void serialize(std::ostream &os);
        virtual void unserialize(Checkpoint *cp, const std::string &section);

        // Most recently used page table entries
        TlbEntry *EntryCache[3];
        inline void flushCache()
        {
            memset(EntryCache, 0, 3 * sizeof(TlbEntry*));
        }

        inline TlbEntry* updateCache(TlbEntry *entry) {
            EntryCache[2] = EntryCache[1];
            EntryCache[1] = EntryCache[0];
            EntryCache[0] = entry;
            return entry;
        }
    };

    class ITB : public TLB
    {
      protected:
        mutable Stats::Scalar<> hits;
        mutable Stats::Scalar<> misses;
        mutable Stats::Scalar<> acv;
        mutable Stats::Formula accesses;

      public:
        ITB(const std::string &name, int size);
        virtual void regStats();

        Fault translate(RequestPtr &req, ThreadContext *tc);
    };

    class DTB : public TLB
    {
      protected:
        mutable Stats::Scalar<> read_hits;
        mutable Stats::Scalar<> read_misses;
        mutable Stats::Scalar<> read_acv;
        mutable Stats::Scalar<> read_accesses;
        mutable Stats::Scalar<> write_hits;
        mutable Stats::Scalar<> write_misses;
        mutable Stats::Scalar<> write_acv;
        mutable Stats::Scalar<> write_accesses;
        Stats::Formula hits;
        Stats::Formula misses;
        Stats::Formula acv;
        Stats::Formula accesses;

      public:
        DTB(const std::string &name, int size);
        virtual void regStats();

        Fault translate(RequestPtr &req, ThreadContext *tc, bool write);
    };
}

#endif // __ALPHA_MEMORY_HH__