tlb.cc

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/*
 * Copyright (c) 2001-2005 The Regents of The University of Michigan
 * Copyright (c) 2007 MIPS Technologies, Inc.
 * Copyright (c) 2007-2008 The Florida State University
 * Copyright (c) 2009 The University of Edinburgh
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#include "arch/power/tlb.hh"
 
#include <string>
#include <vector>
 
#include "arch/power/faults.hh"
#include "arch/power/pagetable.hh"
#include "base/inifile.hh"
#include "base/str.hh"
#include "base/trace.hh"
#include "cpu/thread_context.hh"
#include "debug/Power.hh"
#include "debug/TLB.hh"
#include "mem/page_table.hh"
#include "params/PowerTLB.hh"
#include "sim/full_system.hh"
#include "sim/process.hh"
 
namespace gem5
{
 
using namespace PowerISA;

//
//  POWER TLB
//
 
#define MODE2MASK(X) (1 << (X))
 
TLB::TLB(const Params &p) : BaseTLB(p), size(p.size), nlu(0)
{
    table = new PowerISA::PTE[size];
    memset(table, 0, sizeof(PowerISA::PTE) * size);
    smallPages = 0;
}
 
TLB::~TLB()
{
    if (table)
        delete [] table;
}
 
// look up an entry in the TLB
PowerISA::PTE *
TLB::lookup(Addr vpn, uint8_t asn) const
{
    // assume not found...
    PowerISA::PTE *retval = NULL;
    PageTable::const_iterator i = lookupTable.find(vpn);
    if (i != lookupTable.end()) {
        while (i->first == vpn) {
            int index = i->second;
            PowerISA::PTE *pte = &table[index];
            Addr Mask = pte->Mask;
            Addr InvMask = ~Mask;
            Addr VPN  = pte->VPN;
            if (((vpn & InvMask) == (VPN & InvMask))
               && (pte->G  || (asn == pte->asid))) {
 
                // We have a VPN + ASID Match
                retval = pte;
                break;
            }
            ++i;
        }
    }
 
    DPRINTF(TLB, "lookup %#x, asn %#x -> %s ppn %#x\n", vpn, (int)asn,
            retval ? "hit" : "miss", retval ? retval->PFN1 : 0);
    return retval;
}
 
PowerISA::PTE*
TLB::getEntry(unsigned Index) const
{
    // Make sure that Index is valid
    assert(Index<size);
    return &table[Index];
}
 
int
TLB::probeEntry(Addr vpn,uint8_t asn) const
{
    // assume not found...
    int Ind = -1;
    PageTable::const_iterator i = lookupTable.find(vpn);
    if (i != lookupTable.end()) {
        while (i->first == vpn) {
            int index = i->second;
            PowerISA::PTE *pte = &table[index];
            Addr Mask = pte->Mask;
            Addr InvMask = ~Mask;
            Addr VPN  = pte->VPN;
            if (((vpn & InvMask) == (VPN & InvMask))
                && (pte->G  || (asn == pte->asid))) {
 
                // We have a VPN + ASID Match
                Ind = index;
                break;
            }
            ++i;
        }
    }
 
    DPRINTF(Power, "VPN: %x, asid: %d, Result of TLBP: %d\n", vpn, asn, Ind);
    return Ind;
}
 
inline Fault
TLB::checkCacheability(const RequestPtr &req)
{
    Addr VAddrUncacheable = 0xA0000000;
    if ((req->getVaddr() & VAddrUncacheable) == VAddrUncacheable) {
 
        // mark request as uncacheable
        req->setFlags(Request::UNCACHEABLE | Request::STRICT_ORDER);
    }
    return NoFault;
}
 
void
TLB::insertAt(PowerISA::PTE &pte, unsigned Index, int _smallPages)
{
    smallPages=_smallPages;
    if (Index > size){
        warn("Attempted to write at index (%d) beyond TLB size (%d)",
             Index, size);
    } else {
 
        // Update TLB
        if (table[Index].V0 || table[Index].V1) {
 
            // Previous entry is valid
            PageTable::iterator i = lookupTable.find(table[Index].VPN);
            lookupTable.erase(i);
        }
        table[Index]=pte;
 
        // Update fast lookup table
        lookupTable.insert(std::make_pair(table[Index].VPN, Index));
    }
}
 
// insert a new TLB entry
void
TLB::insert(Addr addr, PowerISA::PTE &pte)
{
    fatal("TLB Insert not yet implemented\n");
}
 
void
TLB::flushAll()
{
    DPRINTF(TLB, "flushAll\n");
    memset(table, 0, sizeof(PowerISA::PTE) * size);
    lookupTable.clear();
    nlu = 0;
}
 
void
TLB::serialize(CheckpointOut &cp) const
{
    SERIALIZE_SCALAR(size);
    SERIALIZE_SCALAR(nlu);
 
    for (int i = 0; i < size; i++) {
        ScopedCheckpointSection sec(cp, csprintf("PTE%d", i));
        table[i].serialize(cp);
    }
}
 
void
TLB::unserialize(CheckpointIn &cp)
{
    UNSERIALIZE_SCALAR(size);
    UNSERIALIZE_SCALAR(nlu);
 
    for (int i = 0; i < size; i++) {
        ScopedCheckpointSection sec(cp, csprintf("PTE%d", i));
        if (table[i].V0 || table[i].V1) {
            lookupTable.insert(std::make_pair(table[i].VPN, i));
        }
    }
}
 
Fault
TLB::translateInst(const RequestPtr &req, ThreadContext *tc)
{
    Addr vaddr = req->getVaddr();
 
    // Instruction accesses must be word-aligned
    if (vaddr & 0x3) {
        DPRINTF(TLB, "Alignment Fault on %#x, size = %d\n", vaddr,
                req->getSize());
        return std::make_shared<AlignmentFault>(vaddr);
    }
 
    return tc->getProcessPtr()->pTable->translate(req);
}
 
Fault
TLB::translateData(const RequestPtr &req, ThreadContext *tc, bool write)
{
    return tc->getProcessPtr()->pTable->translate(req);
}
 
Fault
TLB::translateAtomic(const RequestPtr &req, ThreadContext *tc,
                     BaseMMU::Mode mode)
{
    panic_if(FullSystem,
            "translateAtomic not yet implemented for full system.");
 
    if (mode == BaseMMU::Execute)
        return translateInst(req, tc);
    else
        return translateData(req, tc, mode == BaseMMU::Write);
}
 
Fault
TLB::translateFunctional(const RequestPtr &req, ThreadContext *tc,
                         BaseMMU::Mode mode)
{
    panic_if(FullSystem,
            "translateFunctional not implemented for full system.");
    return tc->getProcessPtr()->pTable->translate(req);
}
 
void
TLB::translateTiming(const RequestPtr &req, ThreadContext *tc,
                     BaseMMU::Translation *translation, BaseMMU::Mode mode)
{
    assert(translation);
    translation->finish(translateAtomic(req, tc, mode), req, tc, mode);
}
 
Fault
TLB::finalizePhysical(const RequestPtr &req,
                      ThreadContext *tc, BaseMMU::Mode mode) const
{
    return NoFault;
}
 
PowerISA::PTE &
TLB::index(bool advance)
{
    PowerISA::PTE *pte = &table[nlu];
 
    if (advance)
        nextnlu();
 
    return *pte;
}
 
} // namespace gem5