pagetable.hh

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/*
 * Copyright (c) 2014 Advanced Micro Devices, Inc.
 * Copyright (c) 2007 The Hewlett-Packard Development Company
 * All rights reserved.
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * 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
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * 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
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 */
 
#ifndef __ARCH_X86_PAGETABLE_HH__
#define __ARCH_X86_PAGETABLE_HH__
 
#include <cstdint>
 
#include "arch/x86/page_size.hh"
#include "base/bitunion.hh"
#include "base/types.hh"
#include "base/trie.hh"
#include "mem/port_proxy.hh"
#include "sim/serialize.hh"
 
namespace gem5
{
 
class ThreadContext;
 
namespace X86ISA
{
    struct TlbEntry;
}
 
typedef Trie<Addr, X86ISA::TlbEntry> TlbEntryTrie;
 
namespace X86ISA
{
    struct TlbEntry : public Serializable
    {
        // The base of the physical page.
        Addr paddr;
 
        // The beginning of the virtual page this entry maps.
        Addr vaddr;
        // The size of the page this represents, in address bits.
        unsigned logBytes;
 
        // Read permission is always available, assuming it isn't blocked by
        // other mechanisms.
        bool writable;
        // Whether this page is accesible without being in supervisor mode.
        bool user;
        // Whether to use write through or write back. M5 ignores this and
        // lets the caches handle the writeback policy.
        //bool pwt;
        // Whether the page is cacheable or not.
        bool uncacheable;
        // Whether or not to kick this page out on a write to CR3.
        bool global;
        // A bit used to form an index into the PAT table.
        bool patBit;
        // Whether or not memory on this page can be executed.
        bool noExec;
        // A sequence number to keep track of LRU.
        uint64_t lruSeq;
 
        TlbEntryTrie::Handle trieHandle;
 
        TlbEntry(Addr asn, Addr _vaddr, Addr _paddr,
                 bool uncacheable, bool read_only);
        TlbEntry();
 
        void
        updateVaddr(Addr new_vaddr)
        {
            vaddr = new_vaddr;
        }
 
        Addr pageStart()
        {
            return paddr;
        }
 
        // Return the page size in bytes
        int size()
        {
            return (1 << logBytes);
        }
 
        void serialize(CheckpointOut &cp) const override;
        void unserialize(CheckpointIn &cp) override;
    };
 
 
    BitUnion64(VAddr)
        Bitfield<20, 12> longl1;
        Bitfield<29, 21> longl2;
        Bitfield<38, 30> longl3;
        Bitfield<47, 39> longl4;
 
        Bitfield<20, 12> pael1;
        Bitfield<29, 21> pael2;
        Bitfield<31, 30> pael3;
 
        Bitfield<21, 12> norml1;
        Bitfield<31, 22> norml2;
    EndBitUnion(VAddr)
 
    // Unfortunately, the placement of the base field in a page table entry is
    // very erratic and would make a mess here. It might be moved here at some
    // point in the future.
    BitUnion64(PageTableEntry)
        Bitfield<63> nx;
        Bitfield<51, 12> base;
        Bitfield<11, 9> avl;
        Bitfield<8> g;
        Bitfield<7> ps;
        Bitfield<6> d;
        Bitfield<5> a;
        Bitfield<4> pcd;
        Bitfield<3> pwt;
        Bitfield<2> u;
        Bitfield<1> w;
        Bitfield<0> p;
    EndBitUnion(PageTableEntry)
 
    template <int first, int last>
    class LongModePTE
    {
      public:
        Addr paddr() { return pte.base << PageShift; }
        void paddr(Addr addr) { pte.base = addr >> PageShift; }
 
        bool present() { return pte.p; }
        void present(bool p) { pte.p = p ? 1 : 0; }
 
        bool uncacheable() { return pte.pcd; }
        void uncacheable(bool u) { pte.pcd = u ? 1 : 0; }
 
        bool readonly() { return !pte.w; }
        void readonly(bool r) { pte.w = r ? 0 : 1; }
 
        void
        read(PortProxy &p, Addr table, Addr vaddr)
        {
            entryAddr = table;
            entryAddr += bits(vaddr, first, last) * sizeof(PageTableEntry);
            pte = p.read<PageTableEntry>(entryAddr);
        }
 
        void
        reset(Addr _paddr, bool _present=true,
              bool _uncacheable=false, bool _readonly=false)
        {
            pte = 0;
            pte.u = 1;
            paddr(_paddr);
            present(_present);
            uncacheable(_uncacheable);
            readonly(_readonly);
        };
 
        void write(PortProxy &p) { p.write(entryAddr, pte); }
 
        static int
        tableSize()
        {
            return 1 << ((first - last) + 4 - PageShift);
        }
 
      protected:
        PageTableEntry pte;
        Addr entryAddr;
    };
 
} // namespace X86ISA
} // namespace gem5
 
#endif