multi_level_page_table.hh

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/*
 * Copyright (c) 2014 Advanced Micro Devices, 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
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 */
 
#ifndef __MEM_MULTI_LEVEL_PAGE_TABLE_HH__
#define __MEM_MULTI_LEVEL_PAGE_TABLE_HH__
 
#include <string>
 
#include "base/types.hh"
#include "debug/MMU.hh"
#include "mem/page_table.hh"
#include "sim/se_workload.hh"
#include "sim/system.hh"
 
namespace gem5
{
 
namespace {
 
template <class First, class ...Rest>
Addr
prepTopTable(System *system, Addr pageSize)
{
    auto *se_workload = dynamic_cast<SEWorkload *>(system->workload);
    fatal_if(!se_workload, "Couldn't find an appropriate workload object.");
    Addr addr = se_workload->allocPhysPages(First::tableSize());
    PortProxy &p = system->physProxy;
    p.memsetBlob(addr, 0, First::tableSize() * pageSize);
    return addr;
}
 
template <class ...Types>
struct LastType;
 
template <class First, class Second, class ...Rest>
struct LastType<First, Second, Rest...>
{
    typedef typename LastType<Second, Rest...>::type type;
};
 
template <class Only>
struct LastType<Only>
{
    typedef Only type;
};
 
 
template <class ...Types>
struct WalkWrapper;
 
template <class Final, class Only>
struct WalkWrapper<Final, Only>
{
    static void
    walk(System *system, Addr pageSize, Addr table, Addr vaddr,
         bool allocate, Final *entry)
    {
        entry->read(system->physProxy, table, vaddr);
    }
};
 
template <class Final, class First, class Second, class ...Rest>
struct WalkWrapper<Final, First, Second, Rest...>
{
    static void
    walk(System *system, Addr pageSize, Addr table, Addr vaddr,
         bool allocate, Final *entry)
    {
        First first;
        first.read(system->physProxy, table, vaddr);
 
        Addr next;
        if (!first.present()) {
            fatal_if(!allocate,
                     "Page fault while walking the page table.");
            next = prepTopTable<Second>(system, pageSize);
            first.reset(next);
            first.write(system->physProxy);
        } else {
            next = first.paddr();
        }
        WalkWrapper<Final, Second, Rest...>::walk(
                system, pageSize, next, vaddr, allocate, entry);
    }
};
 
template <class ...EntryTypes>
void
walk(System *system, Addr pageSize, Addr table, Addr vaddr,
     bool allocate, typename LastType<EntryTypes...>::type *entry)
{
    WalkWrapper<typename LastType<EntryTypes...>::type, EntryTypes...>::walk(
            system, pageSize, table, vaddr, allocate, entry);
}
 
}
 
 
template <class ...EntryTypes>
class MultiLevelPageTable : public EmulationPageTable
{
    typedef typename LastType<EntryTypes...>::type Final;
 
    System *system;
 
    Addr _basePtr;
 
public:
    MultiLevelPageTable(const std::string &__name, uint64_t _pid,
                        System *_sys, Addr _pageSize) :
            EmulationPageTable(__name, _pid, _pageSize), system(_sys)
    {}
 
    ~MultiLevelPageTable() {}
 
    void
    initState() override
    {
        if (shared)
            return;
 
        _basePtr = prepTopTable<EntryTypes...>(system, _pageSize);
    }
 
    Addr basePtr() { return _basePtr; }
 
    void
    map(Addr vaddr, Addr paddr, int64_t size, uint64_t flags = 0) override
    {
        EmulationPageTable::map(vaddr, paddr, size, flags);
 
        Final entry;
 
        for (int64_t offset = 0; offset < size; offset += _pageSize) {
            walk<EntryTypes...>(system, _pageSize, _basePtr,
                                vaddr + offset, true, &entry);
 
            entry.reset(paddr + offset, true, flags & Uncacheable,
                        flags & ReadOnly);
            entry.write(system->physProxy);
 
            DPRINTF(MMU, "New mapping: %#x-%#x\n",
                    vaddr + offset, paddr + offset);
        }
    }
 
    void
    remap(Addr vaddr, int64_t size, Addr new_vaddr) override
    {
        EmulationPageTable::remap(vaddr, size, new_vaddr);
 
        Final old_entry, new_entry;
 
        for (int64_t offset = 0; offset < size; offset += _pageSize) {
            // Unmap the original mapping.
            walk<EntryTypes...>(system, _pageSize, _basePtr, vaddr + offset,
                                false, &old_entry);
            old_entry.present(false);
            old_entry.write(system->physProxy);
 
            // Map the new one.
            walk<EntryTypes...>(system, _pageSize, _basePtr,
                                new_vaddr + offset, true, &new_entry);
            new_entry.reset(old_entry.paddr(), true, old_entry.uncacheable(),
                            old_entry.readonly());
            new_entry.write(system->physProxy);
        }
    }
 
    void
    unmap(Addr vaddr, int64_t size) override
    {
        EmulationPageTable::unmap(vaddr, size);
 
        Final entry;
 
        for (int64_t offset = 0; offset < size; offset += _pageSize) {
            walk<EntryTypes...>(system, _pageSize, _basePtr,
                                vaddr + offset, false, &entry);
            fatal_if(!entry.present(),
                     "PageTable::unmap: Address %#x not mapped.", vaddr);
            entry.present(false);
            entry.write(system->physProxy);
            DPRINTF(MMU, "Unmapping: %#x\n", vaddr);
        }
    }
 
    void
    serialize(CheckpointOut &cp) const override
    {
        EmulationPageTable::serialize(cp);
        paramOut(cp, "ptable.pointer", _basePtr);
    }
 
    void
    unserialize(CheckpointIn &cp) override
    {
        EmulationPageTable::unserialize(cp);
        paramIn(cp, "ptable.pointer", _basePtr);
    }
};
 
} // namespace gem5
 
#endif // __MEM_MULTI_LEVEL_PAGE_TABLE_HH__