xref: /gem5/src/arch/x86/tlb.cc

/*
 * Copyright (c) 2007 The Hewlett-Packard Development Company
 * All rights reserved.
 *
 * Redistribution and use of this software in source and binary forms,
 * with or without modification, are permitted provided that the
 * following conditions are met:
 *
 * The software must be used only for Non-Commercial Use which means any
 * use which is NOT directed to receiving any direct monetary
 * compensation for, or commercial advantage from such use.  Illustrative
 * examples of non-commercial use are academic research, personal study,
 * teaching, education and corporate research & development.
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 * commercial advantage.
 *
 * If you wish to use this software or functionality therein that may be
 * covered by patents for commercial use, please contact:
 *     Director of Intellectual Property Licensing
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 *     Hewlett-Packard Company
 *     1501 Page Mill Road
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 *
 * 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
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 * other materials provided with the distribution.  Neither the name of
 * the COPYRIGHT HOLDER(s), HEWLETT-PACKARD COMPANY, nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.  No right of
 * sublicense is granted herewith.  Derivatives of the software and
 * output created using the software may be prepared, but only for
 * Non-Commercial Uses.  Derivatives of the software may be shared with
 * others provided: (i) the others agree to abide by the list of
 * conditions herein which includes the Non-Commercial Use restrictions;
 * and (ii) such Derivatives of the software include the above copyright
 * notice to acknowledge the contribution from this software where
 * applicable, this list of conditions and the disclaimer below.
 *
 * 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
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 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Authors: Gabe Black
 */

#include <cstring>

#include "config/full_system.hh"

#include "arch/x86/pagetable.hh"
#include "arch/x86/tlb.hh"
#include "base/bitfield.hh"
#include "base/trace.hh"
#include "cpu/thread_context.hh"
#include "cpu/base.hh"
#include "mem/packet_access.hh"
#include "mem/request.hh"
#include "sim/system.hh"

namespace X86ISA {

TLB::TLB(const Params *p) : SimObject(p), size(p->size)
{
    tlb = new TlbEntry[size];
    std::memset(tlb, 0, sizeof(TlbEntry) * size);

    for (int x = 0; x < size; x++)
        freeList.push_back(&tlb[x]);
}

void
TLB::insert(Addr vpn, TlbEntry &entry)
{
    //TODO Deal with conflicting entries

    TlbEntry *newEntry = NULL;
    if (!freeList.empty()) {
        newEntry = freeList.front();
        freeList.pop_front();
    } else {
        newEntry = entryList.back();
        entryList.pop_back();
    }
    *newEntry = entry;
    newEntry->vaddr = vpn;
    entryList.push_front(newEntry);
}

TlbEntry *
TLB::lookup(Addr va, bool update_lru)
{
    //TODO make this smarter at some point
    EntryList::iterator entry;
    for (entry = entryList.begin(); entry != entryList.end(); entry++) {
        if ((*entry)->vaddr <= va && (*entry)->vaddr + (*entry)->size > va) {
            DPRINTF(TLB, "Matched vaddr %#x to entry starting at %#x "
                    "with size %#x.\n", va, (*entry)->vaddr, (*entry)->size);
            TlbEntry *e = *entry;
            if (update_lru) {
                entryList.erase(entry);
                entryList.push_front(e);
            }
            return e;
        }
    }
    return NULL;
}

void
TLB::invalidateAll()
{
}

void
TLB::invalidateNonGlobal()
{
}

void
TLB::demapPage(Addr va)
{
}

template<class TlbFault>
Fault
TLB::translate(RequestPtr &req, ThreadContext *tc, bool write, bool execute)
{
    Addr vaddr = req->getVaddr();
    DPRINTF(TLB, "Translating vaddr %#x.\n", vaddr);
    uint32_t flags = req->getFlags();
    bool storeCheck = flags & StoreCheck;

    int seg = flags & (mask(NUM_SEGMENTREGS));

    //XXX Junk code to surpress the warning
    if (storeCheck) seg = seg;

    // Get cr0. This will tell us how to do translation. We'll assume it was
    // verified to be correct and consistent when set.
    CR0 cr0 = tc->readMiscRegNoEffect(MISCREG_CR0);

    // If protected mode has been enabled...
    if (cr0.pe) {
        Efer efer = tc->readMiscRegNoEffect(MISCREG_EFER);
        SegAttr csAttr = tc->readMiscRegNoEffect(MISCREG_CS_ATTR);
        // If we're not in 64-bit mode, do protection/limit checks
        if (!efer.lma || !csAttr.longMode) {
            SegAttr attr = tc->readMiscRegNoEffect(MISCREG_SEG_ATTR(seg));
            if (!attr.writable && write)
                return new GeneralProtection(0);
            if (!attr.readable && !write && !execute)
                return new GeneralProtection(0);
            Addr base = tc->readMiscRegNoEffect(MISCREG_SEG_BASE(seg));
            Addr limit = tc->readMiscRegNoEffect(MISCREG_SEG_LIMIT(seg));
            if (!attr.expandDown) {
                // We don't have to worry about the access going around the
                // end of memory because accesses will be broken up into
                // pieces at boundaries aligned on sizes smaller than an
                // entire address space. We do have to worry about the limit
                // being less than the base.
                if (limit < base) {
                    if (limit < vaddr + req->getSize() && vaddr < base)
                        return new GeneralProtection(0);
                } else {
                    if (limit < vaddr + req->getSize())
                        return new GeneralProtection(0);
                }
            } else {
                if (limit < base) {
                    if (vaddr <= limit || vaddr + req->getSize() >= base)
                        return new GeneralProtection(0);
                } else {
                    if (vaddr <= limit && vaddr + req->getSize() >= base)
                        return new GeneralProtection(0);
                }
            }
        }
        // If paging is enabled, do the translation.
        if (cr0.pg) {
            // The vaddr already has the segment base applied.
            TlbEntry *entry = lookup(vaddr);
            if (!entry) {
#if FULL_SYSTEM
                return new TlbFault();
#else
                return new TlbFault(vaddr);
#endif
            } else {
                // Do paging protection checks.
                Addr paddr = entry->pageStart | (vaddr & mask(12));
                req->setPaddr(paddr);
            }
        } else {
            //Use the address which already has segmentation applied.
            req->setPaddr(vaddr);
        }
    } else {
        // Real mode
        req->setPaddr(vaddr);
    }
    return NoFault;
};

Fault
DTB::translate(RequestPtr &req, ThreadContext *tc, bool write)
{
    return TLB::translate<FakeDTLBFault>(req, tc, write, false);
}

Fault
ITB::translate(RequestPtr &req, ThreadContext *tc)
{
    return TLB::translate<FakeITLBFault>(req, tc, false, true);
}

#if FULL_SYSTEM

Tick
DTB::doMmuRegRead(ThreadContext *tc, Packet *pkt)
{
    return tc->getCpuPtr()->ticks(1);
}

Tick
DTB::doMmuRegWrite(ThreadContext *tc, Packet *pkt)
{
    return tc->getCpuPtr()->ticks(1);
}

#endif

void
TLB::serialize(std::ostream &os)
{
}

void
TLB::unserialize(Checkpoint *cp, const std::string &section)
{
}

void
DTB::serialize(std::ostream &os)
{
    TLB::serialize(os);
}

void
DTB::unserialize(Checkpoint *cp, const std::string &section)
{
    TLB::unserialize(cp, section);
}

/* end namespace X86ISA */ }

X86ISA::ITB *
X86ITBParams::create()
{
    return new X86ISA::ITB(this);
}

X86ISA::DTB *
X86DTBParams::create()
{
    return new X86ISA::DTB(this);
}