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-/*
- * Copyright (c) 2002-2005 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.
- *
- * Authors: Erik Hallnor
- * Dave Greene
- */
-
-/**
- * @file
- * Miss Status and Handling Register (MSHR) definitions.
- */
-
-#include <assert.h>
-#include <string>
-#include <vector>
-#include <algorithm>
-
-#include "mem/cache/miss/mshr.hh"
-#include "sim/core.hh" // for curTick
-#include "sim/host.hh"
-#include "base/misc.hh"
-#include "mem/cache/cache.hh"
-
-using namespace std;
-
-MSHR::MSHR()
-{
- inService = false;
- ntargets = 0;
- threadNum = -1;
- targets = new TargetList();
- deferredTargets = new TargetList();
-}
-
-
-MSHR::TargetList::TargetList()
- : needsExclusive(false), hasUpgrade(false)
-{}
-
-
-inline void
-MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
- Counter order, bool cpuSide, bool markPending)
-{
- if (cpuSide) {
- if (pkt->needsExclusive()) {
- needsExclusive = true;
- }
-
- if (pkt->cmd == MemCmd::UpgradeReq) {
- hasUpgrade = true;
- }
- }
-
- if (markPending) {
- MSHR *mshr = dynamic_cast<MSHR*>(pkt->senderState);
- if (mshr != NULL) {
- assert(!mshr->downstreamPending);
- mshr->downstreamPending = true;
- }
- }
-
- push_back(Target(pkt, readyTime, order, cpuSide, markPending));
-}
-
-
-void
-MSHR::TargetList::replaceUpgrades()
-{
- if (!hasUpgrade)
- return;
-
- Iterator end_i = end();
- for (Iterator i = begin(); i != end_i; ++i) {
- if (i->pkt->cmd == MemCmd::UpgradeReq) {
- i->pkt->cmd = MemCmd::ReadExReq;
- DPRINTF(Cache, "Replacing UpgradeReq with ReadExReq\n");
- }
- }
-
- hasUpgrade = false;
-}
-
-
-void
-MSHR::TargetList::clearDownstreamPending()
-{
- Iterator end_i = end();
- for (Iterator i = begin(); i != end_i; ++i) {
- if (i->markedPending) {
- MSHR *mshr = dynamic_cast<MSHR*>(i->pkt->senderState);
- if (mshr != NULL) {
- mshr->clearDownstreamPending();
- }
- }
- }
-}
-
-
-bool
-MSHR::TargetList::checkFunctional(PacketPtr pkt)
-{
- Iterator end_i = end();
- for (Iterator i = begin(); i != end_i; ++i) {
- if (pkt->checkFunctional(i->pkt)) {
- return true;
- }
- }
-
- return false;
-}
-
-
-void
-MSHR::TargetList::
-print(std::ostream &os, int verbosity, const std::string &prefix) const
-{
- ConstIterator end_i = end();
- for (ConstIterator i = begin(); i != end_i; ++i) {
- ccprintf(os, "%s%s: ", prefix, i->isCpuSide() ? "cpu" : "mem");
- i->pkt->print(os, verbosity, "");
- }
-}
-
-
-void
-MSHR::allocate(Addr _addr, int _size, PacketPtr target,
- Tick whenReady, Counter _order)
-{
- addr = _addr;
- size = _size;
- readyTime = whenReady;
- order = _order;
- assert(target);
- isCacheFill = false;
- _isUncacheable = target->req->isUncacheable();
- inService = false;
- downstreamPending = false;
- threadNum = 0;
- ntargets = 1;
- // Don't know of a case where we would allocate a new MSHR for a
- // snoop (mem-side request), so set cpuSide to true here.
- assert(targets->isReset());
- targets->add(target, whenReady, _order, true, true);
- assert(deferredTargets->isReset());
- pendingInvalidate = false;
- pendingShared = false;
- data = NULL;
-}
-
-
-void
-MSHR::clearDownstreamPending()
-{
- assert(downstreamPending);
- downstreamPending = false;
- // recursively clear flag on any MSHRs we will be forwarding
- // responses to
- targets->clearDownstreamPending();
-}
-
-bool
-MSHR::markInService()
-{
- assert(!inService);
- if (isSimpleForward()) {
- // we just forwarded the request packet & don't expect a
- // response, so get rid of it
- assert(getNumTargets() == 1);
- popTarget();
- return true;
- }
- inService = true;
- if (!downstreamPending) {
- // let upstream caches know that the request has made it to a
- // level where it's going to get a response
- targets->clearDownstreamPending();
- }
- return false;
-}
-
-
-void
-MSHR::deallocate()
-{
- assert(targets->empty());
- targets->resetFlags();
- assert(deferredTargets->isReset());
- assert(ntargets == 0);
- inService = false;
- //allocIter = NULL;
- //readyIter = NULL;
-}
-
-/*
- * Adds a target to an MSHR
- */
-void
-MSHR::allocateTarget(PacketPtr pkt, Tick whenReady, Counter _order)
-{
- // if there's a request already in service for this MSHR, we will
- // have to defer the new target until after the response if any of
- // the following are true:
- // - there are other targets already deferred
- // - there's a pending invalidate to be applied after the response
- // comes back (but before this target is processed)
- // - the outstanding request is for a non-exclusive block and this
- // target requires an exclusive block
- if (inService &&
- (!deferredTargets->empty() || pendingInvalidate ||
- (!targets->needsExclusive && pkt->needsExclusive()))) {
- // need to put on deferred list
- deferredTargets->add(pkt, whenReady, _order, true, true);
- } else {
- // No request outstanding, or still OK to append to
- // outstanding request: append to regular target list. Only
- // mark pending if current request hasn't been issued yet
- // (isn't in service).
- targets->add(pkt, whenReady, _order, true, !inService);
- }
-
- ++ntargets;
-}
-
-bool
-MSHR::handleSnoop(PacketPtr pkt, Counter _order)
-{
- if (!inService || (pkt->isExpressSnoop() && downstreamPending)) {
- // Request has not been issued yet, or it's been issued
- // locally but is buffered unissued at some downstream cache
- // which is forwarding us this snoop. Either way, the packet
- // we're snooping logically precedes this MSHR's request, so
- // the snoop has no impact on the MSHR, but must be processed
- // in the standard way by the cache. The only exception is
- // that if we're an L2+ cache buffering an UpgradeReq from a
- // higher-level cache, and the snoop is invalidating, then our
- // buffered upgrades must be converted to read exclusives,
- // since the upper-level cache no longer has a valid copy.
- // That is, even though the upper-level cache got out on its
- // local bus first, some other invalidating transaction
- // reached the global bus before the upgrade did.
- if (pkt->needsExclusive()) {
- targets->replaceUpgrades();
- deferredTargets->replaceUpgrades();
- }
-
- return false;
- }
-
- // From here on down, the request issued by this MSHR logically
- // precedes the request we're snooping.
-
- if (pkt->needsExclusive()) {
- // snooped request still precedes the re-request we'll have to
- // issue for deferred targets, if any...
- deferredTargets->replaceUpgrades();
- }
-
- if (pendingInvalidate) {
- // a prior snoop has already appended an invalidation, so
- // logically we don't have the block anymore; no need for
- // further snooping.
- return true;
- }
-
- if (targets->needsExclusive || pkt->needsExclusive()) {
- // actual target device (typ. PhysicalMemory) will delete the
- // packet on reception, so we need to save a copy here
- PacketPtr cp_pkt = new Packet(pkt, true);
- targets->add(cp_pkt, curTick, _order, false,
- downstreamPending && targets->needsExclusive);
- ++ntargets;
-
- if (targets->needsExclusive) {
- // We're awaiting an exclusive copy, so ownership is pending.
- // It's up to us to respond once the data arrives.
- pkt->assertMemInhibit();
- pkt->setSupplyExclusive();
- } else {
- // Someone else may respond before we get around to
- // processing this snoop, which means the copied request
- // pointer will no longer be valid
- cp_pkt->req = NULL;
- }
-
- if (pkt->needsExclusive()) {
- // This transaction will take away our pending copy
- pendingInvalidate = true;
- }
- } else {
- // Read to a read: no conflict, so no need to record as
- // target, but make sure neither reader thinks he's getting an
- // exclusive copy
- pendingShared = true;
- pkt->assertShared();
- }
-
- return true;
-}
-
-
-bool
-MSHR::promoteDeferredTargets()
-{
- assert(targets->empty());
- if (deferredTargets->empty()) {
- return false;
- }
-
- // swap targets & deferredTargets lists
- TargetList *tmp = targets;
- targets = deferredTargets;
- deferredTargets = tmp;
-
- assert(targets->size() == ntargets);
-
- // clear deferredTargets flags
- deferredTargets->resetFlags();
-
- pendingInvalidate = false;
- pendingShared = false;
- order = targets->front().order;
- readyTime = std::max(curTick, targets->front().readyTime);
-
- return true;
-}
-
-
-void
-MSHR::handleFill(Packet *pkt, CacheBlk *blk)
-{
- if (pendingShared) {
- // we snooped another read while this read was in
- // service... assert shared line on its behalf
- pkt->assertShared();
- }
-
- if (!pkt->sharedAsserted() && !pendingInvalidate
- && deferredTargets->needsExclusive) {
- // We got an exclusive response, but we have deferred targets
- // which are waiting to request an exclusive copy (not because
- // of a pending invalidate). This can happen if the original
- // request was for a read-only (non-exclusive) block, but we
- // got an exclusive copy anyway because of the E part of the
- // MOESI/MESI protocol. Since we got the exclusive copy
- // there's no need to defer the targets, so move them up to
- // the regular target list.
- assert(!targets->needsExclusive);
- targets->needsExclusive = true;
- // if any of the deferred targets were upper-level cache
- // requests marked downstreamPending, need to clear that
- assert(!downstreamPending); // not pending here anymore
- deferredTargets->clearDownstreamPending();
- // this clears out deferredTargets too
- targets->splice(targets->end(), *deferredTargets);
- deferredTargets->resetFlags();
- }
-}
-
-
-bool
-MSHR::checkFunctional(PacketPtr pkt)
-{
- // For printing, we treat the MSHR as a whole as single entity.
- // For other requests, we iterate over the individual targets
- // since that's where the actual data lies.
- if (pkt->isPrint()) {
- pkt->checkFunctional(this, addr, size, NULL);
- return false;
- } else {
- return (targets->checkFunctional(pkt) ||
- deferredTargets->checkFunctional(pkt));
- }
-}
-
-
-void
-MSHR::print(std::ostream &os, int verbosity, const std::string &prefix) const
-{
- ccprintf(os, "%s[%x:%x] %s %s %s state: %s %s %s %s\n",
- prefix, addr, addr+size-1,
- isCacheFill ? "Fill" : "",
- needsExclusive() ? "Excl" : "",
- _isUncacheable ? "Unc" : "",
- inService ? "InSvc" : "",
- downstreamPending ? "DwnPend" : "",
- pendingInvalidate ? "PendInv" : "",
- pendingShared ? "PendShared" : "");
-
- ccprintf(os, "%s Targets:\n", prefix);
- targets->print(os, verbosity, prefix + " ");
- if (!deferredTargets->empty()) {
- ccprintf(os, "%s Deferred Targets:\n", prefix);
- deferredTargets->print(os, verbosity, prefix + " ");
- }
-}
-
-MSHR::~MSHR()
-{
-}
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