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

/*
 * Copyright (c) 2003 The Regents of The University of Michigan
 * 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.
 */

#include <sstream>
#include <string>
#include <vector>

#include "base/inifile.hh"
#include "base/str.hh"
#include "base/trace.hh"
#include "cpu/exec_context.hh"
#include "sim/builder.hh"
#include "targetarch/alpha_memory.hh"
#include "targetarch/ev5.hh"

using namespace std;

///////////////////////////////////////////////////////////////////////
//
//  Alpha TLB
//

#ifdef DEBUG
    bool uncacheBit39 = false;
    bool uncacheBit40 = false;
#endif

AlphaTlb::AlphaTlb(const string &name, int s)
    : SimObject(name), size(s), nlu(0)
{
    table = new AlphaISA::PTE[size];
    memset(table, 0, sizeof(AlphaISA::PTE[size]));
}

AlphaTlb::~AlphaTlb()
{
    if (table)
        delete [] table;
}

// look up an entry in the TLB
AlphaISA::PTE *
AlphaTlb::lookup(Addr vpn, uint8_t asn) const
{
    DPRINTF(TLB, "lookup %#x\n", vpn);

    PageTable::const_iterator i = lookupTable.find(vpn);
    if (i == lookupTable.end())
        return NULL;

    while (i->first == vpn) {
        int index = i->second;
        AlphaISA::PTE *pte = &table[index];
        assert(pte->valid);
        if (vpn == pte->tag && (pte->asma || pte->asn == asn))
            return pte;

        ++i;
    }

    // not found...
    return NULL;
}


void
AlphaTlb::checkCacheability(MemReqPtr &req)
{
    // in Alpha, cacheability is controlled by upper-level bits of the
    // physical address

    /*
     * We support having the uncacheable bit in either bit 39 or bit 40.
     * The Turbolaser platform (and EV5) support having the bit in 39, but
     * Tsunami (which Linux assumes uses an EV6) generates accesses with
     * the bit in 40.  So we must check for both, but we have debug flags
     * to catch a weird case where both are used, which shouldn't happen.
     */

    if (req->paddr & PA_UNCACHED_BIT_40 ||
        req->paddr & PA_UNCACHED_BIT_39) {

#ifdef DEBUG
        if (req->paddr & PA_UNCACHED_BIT_40) {
            if(uncacheBit39)
                panic("Bit 40 access follows bit 39 access, PA=%x\n",
                      req->paddr);

            uncacheBit40 = true;
        } else if (req->paddr & PA_UNCACHED_BIT_39) {
            if(uncacheBit40)
                panic("Bit 39 acceess follows bit 40 access, PA=%x\n",
                      req->paddr);

            uncacheBit39 = true;
        }
#endif

        // IPR memory space not implemented
        if (PA_IPR_SPACE(req->paddr))
            if (!req->xc->misspeculating())
                panic("IPR memory space not implemented! PA=%x\n",
                      req->paddr);

        // mark request as uncacheable
        req->flags |= UNCACHEABLE;
    }
}


// insert a new TLB entry
void
AlphaTlb::insert(Addr vaddr, AlphaISA::PTE &pte)
{
    if (table[nlu].valid) {
        Addr oldvpn = table[nlu].tag;
        PageTable::iterator i = lookupTable.find(oldvpn);

        if (i == lookupTable.end())
            panic("TLB entry not found in lookupTable");

        int index;
        while ((index = i->second) != nlu) {
            if (table[index].tag != oldvpn)
                panic("TLB entry not found in lookupTable");

            ++i;
        }

        DPRINTF(TLB, "remove @%d: %#x -> %#x\n", nlu, oldvpn, table[nlu].ppn);

        lookupTable.erase(i);
    }

    Addr vpn = VA_VPN(vaddr);
    DPRINTF(TLB, "insert @%d: %#x -> %#x\n", nlu, vpn, pte.ppn);

    table[nlu] = pte;
    table[nlu].tag = vpn;
    table[nlu].valid = true;

    lookupTable.insert(make_pair(vpn, nlu));
    nextnlu();
}

void
AlphaTlb::flushAll()
{
    memset(table, 0, sizeof(AlphaISA::PTE[size]));
    lookupTable.clear();
    nlu = 0;
}

void
AlphaTlb::flushProcesses()
{
    PageTable::iterator i = lookupTable.begin();
    PageTable::iterator end = lookupTable.end();
    while (i != end) {
        int index = i->second;
        AlphaISA::PTE *pte = &table[index];
        assert(pte->valid);

        if (!pte->asma) {
            DPRINTF(TLB, "flush @%d: %#x -> %#x\n", index, pte->tag, pte->ppn);
            pte->valid = false;
            lookupTable.erase(i);
        }

        ++i;
    }
}

void
AlphaTlb::flushAddr(Addr vaddr, uint8_t asn)
{
    Addr vpn = VA_VPN(vaddr);

    PageTable::iterator i = lookupTable.find(vpn);
    if (i == lookupTable.end())
        return;

    while (i->first == vpn) {
        int index = i->second;
        AlphaISA::PTE *pte = &table[index];
        assert(pte->valid);

        if (vpn == pte->tag && (pte->asma || pte->asn == asn)) {
            DPRINTF(TLB, "flushaddr @%d: %#x -> %#x\n", index, vpn, pte->ppn);

            // invalidate this entry
            pte->valid = false;

            lookupTable.erase(i);
        }

        ++i;
    }
}


void
AlphaTlb::serialize(ostream &os)
{
    SERIALIZE_SCALAR(size);
    SERIALIZE_SCALAR(nlu);

    for (int i = 0; i < size; i++) {
        nameOut(os, csprintf("%s.PTE%d", name(), i));
        table[i].serialize(os);
    }
}

void
AlphaTlb::unserialize(Checkpoint *cp, const string &section)
{
    UNSERIALIZE_SCALAR(size);
    UNSERIALIZE_SCALAR(nlu);

    for (int i = 0; i < size; i++) {
        table[i].unserialize(cp, csprintf("%s.PTE%d", section, i));
        if (table[i].valid) {
            lookupTable.insert(make_pair(table[i].tag, i));
        }
    }
}


///////////////////////////////////////////////////////////////////////
//
//  Alpha ITB
//
AlphaItb::AlphaItb(const std::string &name, int size)
    : AlphaTlb(name, size)
{}


void
AlphaItb::regStats()
{
    hits
        .name(name() + ".hits")
        .desc("ITB hits");
    misses
        .name(name() + ".misses")
        .desc("ITB misses");
    acv
        .name(name() + ".acv")
        .desc("ITB acv");
    accesses
        .name(name() + ".accesses")
        .desc("ITB accesses");

    accesses = hits + misses;
}

void
AlphaItb::fault(Addr pc, ExecContext *xc) const
{
    uint64_t *ipr = xc->regs.ipr;

    if (!xc->misspeculating()) {
        ipr[AlphaISA::IPR_ITB_TAG] = pc;
        ipr[AlphaISA::IPR_IFAULT_VA_FORM] =
            ipr[AlphaISA::IPR_IVPTBR] | (VA_VPN(pc) << 3);
    }
}


Fault
AlphaItb::translate(MemReqPtr &req) const
{
    InternalProcReg *ipr = req->xc->regs.ipr;

    if (PC_PAL(req->vaddr)) {
        // strip off PAL PC marker (lsb is 1)
        req->paddr = (req->vaddr & ~3) & PA_IMPL_MASK;
        hits++;
        return No_Fault;
    }

    if (req->flags & PHYSICAL) {
        req->paddr = req->vaddr;
    } else {
        // verify that this is a good virtual address
        if (!validVirtualAddress(req->vaddr)) {
            fault(req->vaddr, req->xc);
            acv++;
            return Itb_Acv_Fault;
        }

        // Check for "superpage" mapping: when SP<1> is set, and
        // VA<42:41> == 2, VA<39:13> maps directly to PA<39:13>.
        if ((MCSR_SP(ipr[AlphaISA::IPR_MCSR]) & 2) &&
               VA_SPACE(req->vaddr) == 2) {

            // only valid in kernel mode
            if (ICM_CM(ipr[AlphaISA::IPR_ICM]) != AlphaISA::mode_kernel) {
                fault(req->vaddr, req->xc);
                acv++;
                return Itb_Acv_Fault;
            }

            req->paddr = req->vaddr & PA_IMPL_MASK;

            // sign extend the physical address properly
            if (req->paddr & PA_UNCACHED_BIT_39 ||
                req->paddr & PA_UNCACHED_BIT_40)
                req->paddr |= 0xf0000000000;
            else
                req->paddr &= 0xffffffffff;

        } else {
            // not a physical address: need to look up pte
            AlphaISA::PTE *pte = lookup(VA_VPN(req->vaddr),
                                 DTB_ASN_ASN(ipr[AlphaISA::IPR_DTB_ASN]));

            if (!pte) {
                fault(req->vaddr, req->xc);
                misses++;
                return Itb_Fault_Fault;
            }

            req->paddr = PA_PFN2PA(pte->ppn) + VA_POFS(req->vaddr & ~3);

            // check permissions for this access
            if (!(pte->xre & (1 << ICM_CM(ipr[AlphaISA::IPR_ICM])))) {
                // instruction access fault
                fault(req->vaddr, req->xc);
                acv++;
                return Itb_Acv_Fault;
            }

            hits++;
        }
    }

    // check that the physical address is ok (catch bad physical addresses)
    if (req->paddr & ~PA_IMPL_MASK)
        return Machine_Check_Fault;

    checkCacheability(req);

    return No_Fault;
}

///////////////////////////////////////////////////////////////////////
//
//  Alpha DTB
//
AlphaDtb::AlphaDtb(const std::string &name, int size)
    : AlphaTlb(name, size)
{}

void
AlphaDtb::regStats()
{
    read_hits
        .name(name() + ".read_hits")
        .desc("DTB read hits")
        ;

    read_misses
        .name(name() + ".read_misses")
        .desc("DTB read misses")
        ;

    read_acv
        .name(name() + ".read_acv")
        .desc("DTB read access violations")
        ;

    read_accesses
        .name(name() + ".read_accesses")
        .desc("DTB read accesses")
        ;

    write_hits
        .name(name() + ".write_hits")
        .desc("DTB write hits")
        ;

    write_misses
        .name(name() + ".write_misses")
        .desc("DTB write misses")
        ;

    write_acv
        .name(name() + ".write_acv")
        .desc("DTB write access violations")
        ;

    write_accesses
        .name(name() + ".write_accesses")
        .desc("DTB write accesses")
        ;

    hits
        .name(name() + ".hits")
        .desc("DTB hits")
        ;

    misses
        .name(name() + ".misses")
        .desc("DTB misses")
        ;

    acv
        .name(name() + ".acv")
        .desc("DTB access violations")
        ;

    accesses
        .name(name() + ".accesses")
        .desc("DTB accesses")
        ;

    hits = read_hits + write_hits;
    misses = read_misses + write_misses;
    acv = read_acv + write_acv;
    accesses = read_accesses + write_accesses;
}

void
AlphaDtb::fault(Addr vaddr, uint64_t flags, ExecContext *xc) const
{
    uint64_t *ipr = xc->regs.ipr;

    // set fault address and flags
    if (!xc->misspeculating() && !xc->regs.intrlock) {
        // set VA register with faulting address
        ipr[AlphaISA::IPR_VA] = vaddr;

        // set MM_STAT register flags
        ipr[AlphaISA::IPR_MM_STAT] = (((xc->regs.opcode & 0x3f) << 11)
                               | ((xc->regs.ra & 0x1f) << 6)
                               | (flags & 0x3f));

        // set VA_FORM register with faulting formatted address
        ipr[AlphaISA::IPR_VA_FORM] =
            ipr[AlphaISA::IPR_MVPTBR] | (VA_VPN(vaddr) << 3);

        // lock these registers until the VA register is read
        xc->regs.intrlock = true;
    }
}

Fault
AlphaDtb::translate(MemReqPtr &req, bool write) const
{
    RegFile *regs = &req->xc->regs;
    Addr pc = regs->pc;
    InternalProcReg *ipr = regs->ipr;

    AlphaISA::mode_type mode =
        (AlphaISA::mode_type)DTB_CM_CM(ipr[AlphaISA::IPR_DTB_CM]);

    if (PC_PAL(pc)) {
        mode = (req->flags & ALTMODE) ?
            (AlphaISA::mode_type)ALT_MODE_AM(ipr[AlphaISA::IPR_ALT_MODE])
            : AlphaISA::mode_kernel;
    }

    if (req->flags & PHYSICAL) {
        req->paddr = req->vaddr;
    } else {
        // verify that this is a good virtual address
        if (!validVirtualAddress(req->vaddr)) {
            fault(req->vaddr,
                  ((write ? MM_STAT_WR_MASK : 0) | MM_STAT_BAD_VA_MASK |
                   MM_STAT_ACV_MASK),
                  req->xc);

            if (write) { write_acv++; } else { read_acv++; }
            return Dtb_Fault_Fault;
        }

        // Check for "superpage" mapping: when SP<1> is set, and
        // VA<42:41> == 2, VA<39:13> maps directly to PA<39:13>.
        if ((MCSR_SP(ipr[AlphaISA::IPR_MCSR]) & 2) &&
            VA_SPACE(req->vaddr) == 2) {

            // only valid in kernel mode
            if (DTB_CM_CM(ipr[AlphaISA::IPR_DTB_CM]) !=
                AlphaISA::mode_kernel) {
                fault(req->vaddr,
                      ((write ? MM_STAT_WR_MASK : 0) | MM_STAT_ACV_MASK),
                      req->xc);
                if (write) { write_acv++; } else { read_acv++; }
                return Dtb_Acv_Fault;
            }

            req->paddr = req->vaddr & PA_IMPL_MASK;

            // sign extend the physical address properly
            if (req->paddr & PA_UNCACHED_BIT_39 ||
                req->paddr & PA_UNCACHED_BIT_40)
                req->paddr |= 0xf0000000000;
            else
                req->paddr &= 0xffffffffff;

        } else {
            if (write)
                write_accesses++;
            else
                read_accesses++;

            // not a physical address: need to look up pte
            AlphaISA::PTE *pte = lookup(VA_VPN(req->vaddr),
                                 DTB_ASN_ASN(ipr[AlphaISA::IPR_DTB_ASN]));

            if (!pte) {
                // page fault
                fault(req->vaddr,
                      ((write ? MM_STAT_WR_MASK : 0) | MM_STAT_DTB_MISS_MASK),
                      req->xc);
                if (write) { write_misses++; } else { read_misses++; }
                return (req->flags & VPTE) ? Pdtb_Miss_Fault : Ndtb_Miss_Fault;
            }

            req->paddr = PA_PFN2PA(pte->ppn) | VA_POFS(req->vaddr);

            if (write) {
                if (!(pte->xwe & MODE2MASK(mode))) {
                    // declare the instruction access fault
                    fault(req->vaddr, MM_STAT_WR_MASK | MM_STAT_ACV_MASK |
                          (pte->fonw ? MM_STAT_FONW_MASK : 0),
                          req->xc);
                    write_acv++;
                    return Dtb_Fault_Fault;
                }
                if (pte->fonw) {
                    fault(req->vaddr, MM_STAT_WR_MASK | MM_STAT_FONW_MASK,
                          req->xc);
                    write_acv++;
                    return Dtb_Fault_Fault;
                }
            } else {
                if (!(pte->xre & MODE2MASK(mode))) {
                    fault(req->vaddr,
                          MM_STAT_ACV_MASK |
                          (pte->fonr ? MM_STAT_FONR_MASK : 0),
                          req->xc);
                    read_acv++;
                    return Dtb_Acv_Fault;
                }
                if (pte->fonr) {
                    fault(req->vaddr, MM_STAT_FONR_MASK, req->xc);
                    read_acv++;
                    return Dtb_Fault_Fault;
                }
            }
        }

        if (write)
            write_hits++;
        else
            read_hits++;
    }

    // check that the physical address is ok (catch bad physical addresses)
    if (req->paddr & ~PA_IMPL_MASK)
        return Machine_Check_Fault;

    checkCacheability(req);

    return No_Fault;
}

AlphaISA::PTE &
AlphaTlb::index(bool advance)
{
    AlphaISA::PTE *pte = &table[nlu];

    if (advance)
        nextnlu();

    return *pte;
}

BEGIN_DECLARE_SIM_OBJECT_PARAMS(AlphaItb)

    Param<int> size;

END_DECLARE_SIM_OBJECT_PARAMS(AlphaItb)

BEGIN_INIT_SIM_OBJECT_PARAMS(AlphaItb)

    INIT_PARAM_DFLT(size, "TLB size", 48)

END_INIT_SIM_OBJECT_PARAMS(AlphaItb)


CREATE_SIM_OBJECT(AlphaItb)
{
    return new AlphaItb(getInstanceName(), size);
}

REGISTER_SIM_OBJECT("AlphaITB", AlphaItb)

BEGIN_DECLARE_SIM_OBJECT_PARAMS(AlphaDtb)

    Param<int> size;

END_DECLARE_SIM_OBJECT_PARAMS(AlphaDtb)

BEGIN_INIT_SIM_OBJECT_PARAMS(AlphaDtb)

    INIT_PARAM_DFLT(size, "TLB size", 64)

END_INIT_SIM_OBJECT_PARAMS(AlphaDtb)


CREATE_SIM_OBJECT(AlphaDtb)
{
    return new AlphaDtb(getInstanceName(), size);
}

REGISTER_SIM_OBJECT("AlphaDTB", AlphaDtb)