xref: /gem5/src/arch/mips/pagetable.hh

/*
 * 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.
 *
 * Authors: Jaidev Patwardhan
 */

#ifndef __ARCH_MIPS_PAGETABLE_H__
#define __ARCH_MIPS_PAGETABLE_H__

#include "arch/mips/isa_traits.hh"
#include "arch/mips/utility.hh"
#include "arch/mips/vtophys.hh"
#include "config/full_system.hh"

namespace MipsISA {

    struct VAddr
    {
        static const int ImplBits = 43;
        static const Addr ImplMask = (ULL(1) << ImplBits) - 1;
        static const Addr UnImplMask = ~ImplMask;

        VAddr(Addr a) : addr(a) {}
        Addr addr;
        operator Addr() const { return addr; }
        const VAddr &operator=(Addr a) { addr = a; return *this; }

        Addr vpn() const { return (addr & ImplMask) >> PageShift; }
        Addr page() const { return addr & Page_Mask; }
        Addr offset() const { return addr & PageOffset; }

        Addr level3() const
        { return MipsISA::PteAddr(addr >> PageShift); }
        Addr level2() const
        { return MipsISA::PteAddr(addr >> NPtePageShift + PageShift); }
        Addr level1() const
        { return MipsISA::PteAddr(addr >> 2 * NPtePageShift + PageShift); }
    };

    // ITB/DTB page table entry
    struct PTE
    {
      Addr Mask; // What parts of the VAddr (from bits 28..11) should be used in translation (includes Mask and MaskX from PageMask)
      Addr VPN; // Virtual Page Number (/2) (Includes VPN2 + VPN2X .. bits 31..11 from EntryHi)
      uint8_t asid; // Address Space ID (8 bits) // Lower 8 bits of EntryHi

      bool G;    // Global Bit - Obtained by an *AND* of EntryLo0 and EntryLo1 G bit

      /* Contents of Entry Lo0 */
      Addr PFN0; // Physical Frame Number - Even
      bool D0;   // Even entry Dirty Bit
      bool V0;   // Even entry Valid Bit
      uint8_t C0; // Cache Coherency Bits - Even

      /* Contents of Entry Lo1 */
      Addr PFN1; // Physical Frame Number - Odd
      bool D1;   // Odd entry Dirty Bit
      bool V1;   // Odd entry Valid Bit
      uint8_t C1; // Cache Coherency Bits (3 bits)

      /* The next few variables are put in as optimizations to reduce TLB lookup overheads */
      /* For a given Mask, what is the address shift amount, and what is the OffsetMask */
      int AddrShiftAmount;
      int OffsetMask;

      bool Valid() { return (V0 | V1);};
        void serialize(std::ostream &os);
        void unserialize(Checkpoint *cp, const std::string &section);
    };

};
#endif // __ARCH_MIPS_PAGETABLE_H__