tlb.hh

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/*
 * Copyright (c) 2001-2005 The Regents of The University of Michigan
 * Copyright (c) 2007 MIPS Technologies, Inc.
 * 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.
 */
 
#ifndef __ARCH_MIPS_TLB_HH__
#define __ARCH_MIPS_TLB_HH__
 
#include <map>
 
#include "arch/generic/tlb.hh"
#include "arch/mips/pagetable.hh"
#include "arch/mips/utility.hh"
#include "base/statistics.hh"
#include "mem/request.hh"
#include "params/MipsTLB.hh"
#include "sim/sim_object.hh"
 
namespace gem5
{
 
class ThreadContext;
 
/* MIPS does not distinguish between a DTLB and an ITLB -> unified TLB
   However, to maintain compatibility with other architectures, we'll
   simply create an ITLB and DTLB that will point to the real TLB */
namespace MipsISA {
 
class TLB : public BaseTLB
{
  protected:
    typedef std::multimap<Addr, int> PageTable;
    PageTable lookupTable;      // Quick lookup into page table
 
    MipsISA::PTE *table;        // the Page Table
    int size;                   // TLB Size
    int nlu;                    // not last used entry (for replacement)
 
    void nextnlu() { if (++nlu >= size) nlu = 0; }
    MipsISA::PTE *lookup(Addr vpn, uint8_t asn) const;
 
  public:
    typedef MipsTLBParams Params;
    TLB(const Params &p);
 
    int probeEntry(Addr vpn,uint8_t) const;
    MipsISA::PTE *getEntry(unsigned) const;
    virtual ~TLB();
 
    void takeOverFrom(BaseTLB *otlb) override {}
 
    int smallPages;
    int getsize() const { return size; }
 
    MipsISA::PTE &index(bool advance = true);
    void insert(Addr vaddr, MipsISA::PTE &pte);
    void insertAt(MipsISA::PTE &pte, unsigned Index, int _smallPages);
    void flushAll() override;
    void demapPage(Addr vaddr, uint64_t asn) override
    {
        panic("demapPage unimplemented.\n");
    }
 
    // static helper functions... really
    static bool validVirtualAddress(Addr vaddr);
 
    static Fault checkCacheability(const RequestPtr &req);
 
    // Checkpointing
    void serialize(CheckpointOut &cp) const override;
    void unserialize(CheckpointIn &cp) override;
 
    Fault translateAtomic(
        const RequestPtr &req, ThreadContext *tc, BaseMMU::Mode mode) override;
    void translateTiming(
        const RequestPtr &req, ThreadContext *tc,
        BaseMMU::Translation *translation, BaseMMU::Mode mode) override;
    Fault translateFunctional(
        const RequestPtr &req, ThreadContext *tc, BaseMMU::Mode mode) override;
    Fault finalizePhysical(
        const RequestPtr &req,
        ThreadContext *tc, BaseMMU::Mode mode) const override;
};
 
} // namespace MipsISA
} // namespace gem5
 
#endif // __MIPS_MEMORY_HH__