base.cc revision 12729:9870d6f73e04
1/*
2 * Copyright (c) 2012-2013, 2018 ARM Limited
3 * All rights reserved.
4 *
5 * The license below extends only to copyright in the software and shall
6 * not be construed as granting a license to any other intellectual
7 * property including but not limited to intellectual property relating
8 * to a hardware implementation of the functionality of the software
9 * licensed hereunder.  You may use the software subject to the license
10 * terms below provided that you ensure that this notice is replicated
11 * unmodified and in its entirety in all distributions of the software,
12 * modified or unmodified, in source code or in binary form.
13 *
14 * Copyright (c) 2003-2005 The Regents of The University of Michigan
15 * All rights reserved.
16 *
17 * Redistribution and use in source and binary forms, with or without
18 * modification, are permitted provided that the following conditions are
19 * met: redistributions of source code must retain the above copyright
20 * notice, this list of conditions and the following disclaimer;
21 * redistributions in binary form must reproduce the above copyright
22 * notice, this list of conditions and the following disclaimer in the
23 * documentation and/or other materials provided with the distribution;
24 * neither the name of the copyright holders nor the names of its
25 * contributors may be used to endorse or promote products derived from
26 * this software without specific prior written permission.
27 *
28 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
29 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
30 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
31 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
32 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
33 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
34 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
35 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
36 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
37 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
38 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
39 *
40 * Authors: Erik Hallnor
41 *          Nikos Nikoleris
42 */
43
44/**
45 * @file
46 * Definition of BaseCache functions.
47 */
48
49#include "mem/cache/base.hh"
50
51#include "base/compiler.hh"
52#include "base/logging.hh"
53#include "debug/Cache.hh"
54#include "debug/CachePort.hh"
55#include "debug/CacheVerbose.hh"
56#include "mem/cache/mshr.hh"
57#include "mem/cache/prefetch/base.hh"
58#include "mem/cache/queue_entry.hh"
59#include "params/BaseCache.hh"
60#include "sim/core.hh"
61
62class BaseMasterPort;
63class BaseSlavePort;
64
65using namespace std;
66
67BaseCache::CacheSlavePort::CacheSlavePort(const std::string &_name,
68                                          BaseCache *_cache,
69                                          const std::string &_label)
70    : QueuedSlavePort(_name, _cache, queue), queue(*_cache, *this, _label),
71      blocked(false), mustSendRetry(false),
72      sendRetryEvent([this]{ processSendRetry(); }, _name)
73{
74}
75
76BaseCache::BaseCache(const BaseCacheParams *p, unsigned blk_size)
77    : MemObject(p),
78      cpuSidePort (p->name + ".cpu_side", this, "CpuSidePort"),
79      memSidePort(p->name + ".mem_side", this, "MemSidePort"),
80      mshrQueue("MSHRs", p->mshrs, 0, p->demand_mshr_reserve), // see below
81      writeBuffer("write buffer", p->write_buffers, p->mshrs), // see below
82      tags(p->tags),
83      prefetcher(p->prefetcher),
84      prefetchOnAccess(p->prefetch_on_access),
85      writebackClean(p->writeback_clean),
86      tempBlockWriteback(nullptr),
87      writebackTempBlockAtomicEvent([this]{ writebackTempBlockAtomic(); },
88                                    name(), false,
89                                    EventBase::Delayed_Writeback_Pri),
90      blkSize(blk_size),
91      lookupLatency(p->tag_latency),
92      dataLatency(p->data_latency),
93      forwardLatency(p->tag_latency),
94      fillLatency(p->data_latency),
95      responseLatency(p->response_latency),
96      numTarget(p->tgts_per_mshr),
97      forwardSnoops(true),
98      clusivity(p->clusivity),
99      isReadOnly(p->is_read_only),
100      blocked(0),
101      order(0),
102      noTargetMSHR(nullptr),
103      missCount(p->max_miss_count),
104      addrRanges(p->addr_ranges.begin(), p->addr_ranges.end()),
105      system(p->system)
106{
107    // the MSHR queue has no reserve entries as we check the MSHR
108    // queue on every single allocation, whereas the write queue has
109    // as many reserve entries as we have MSHRs, since every MSHR may
110    // eventually require a writeback, and we do not check the write
111    // buffer before committing to an MSHR
112
113    // forward snoops is overridden in init() once we can query
114    // whether the connected master is actually snooping or not
115
116    tempBlock = new CacheBlk();
117    tempBlock->data = new uint8_t[blkSize];
118
119    tags->setCache(this);
120    if (prefetcher)
121        prefetcher->setCache(this);
122}
123
124BaseCache::~BaseCache()
125{
126    delete [] tempBlock->data;
127    delete tempBlock;
128}
129
130void
131BaseCache::CacheSlavePort::setBlocked()
132{
133    assert(!blocked);
134    DPRINTF(CachePort, "Port is blocking new requests\n");
135    blocked = true;
136    // if we already scheduled a retry in this cycle, but it has not yet
137    // happened, cancel it
138    if (sendRetryEvent.scheduled()) {
139        owner.deschedule(sendRetryEvent);
140        DPRINTF(CachePort, "Port descheduled retry\n");
141        mustSendRetry = true;
142    }
143}
144
145void
146BaseCache::CacheSlavePort::clearBlocked()
147{
148    assert(blocked);
149    DPRINTF(CachePort, "Port is accepting new requests\n");
150    blocked = false;
151    if (mustSendRetry) {
152        // @TODO: need to find a better time (next cycle?)
153        owner.schedule(sendRetryEvent, curTick() + 1);
154    }
155}
156
157void
158BaseCache::CacheSlavePort::processSendRetry()
159{
160    DPRINTF(CachePort, "Port is sending retry\n");
161
162    // reset the flag and call retry
163    mustSendRetry = false;
164    sendRetryReq();
165}
166
167void
168BaseCache::init()
169{
170    if (!cpuSidePort.isConnected() || !memSidePort.isConnected())
171        fatal("Cache ports on %s are not connected\n", name());
172    cpuSidePort.sendRangeChange();
173    forwardSnoops = cpuSidePort.isSnooping();
174}
175
176BaseMasterPort &
177BaseCache::getMasterPort(const std::string &if_name, PortID idx)
178{
179    if (if_name == "mem_side") {
180        return memSidePort;
181    }  else {
182        return MemObject::getMasterPort(if_name, idx);
183    }
184}
185
186BaseSlavePort &
187BaseCache::getSlavePort(const std::string &if_name, PortID idx)
188{
189    if (if_name == "cpu_side") {
190        return cpuSidePort;
191    } else {
192        return MemObject::getSlavePort(if_name, idx);
193    }
194}
195
196bool
197BaseCache::inRange(Addr addr) const
198{
199    for (const auto& r : addrRanges) {
200        if (r.contains(addr)) {
201            return true;
202       }
203    }
204    return false;
205}
206
207void
208BaseCache::handleTimingReqHit(PacketPtr pkt, CacheBlk *blk, Tick request_time)
209{
210    if (pkt->needsResponse()) {
211        pkt->makeTimingResponse();
212        // @todo: Make someone pay for this
213        pkt->headerDelay = pkt->payloadDelay = 0;
214
215        // In this case we are considering request_time that takes
216        // into account the delay of the xbar, if any, and just
217        // lat, neglecting responseLatency, modelling hit latency
218        // just as lookupLatency or or the value of lat overriden
219        // by access(), that calls accessBlock() function.
220        cpuSidePort.schedTimingResp(pkt, request_time, true);
221    } else {
222        DPRINTF(Cache, "%s satisfied %s, no response needed\n", __func__,
223                pkt->print());
224
225        // queue the packet for deletion, as the sending cache is
226        // still relying on it; if the block is found in access(),
227        // CleanEvict and Writeback messages will be deleted
228        // here as well
229        pendingDelete.reset(pkt);
230    }
231}
232
233void
234BaseCache::handleTimingReqMiss(PacketPtr pkt, MSHR *mshr, CacheBlk *blk,
235                               Tick forward_time, Tick request_time)
236{
237    if (mshr) {
238        /// MSHR hit
239        /// @note writebacks will be checked in getNextMSHR()
240        /// for any conflicting requests to the same block
241
242        //@todo remove hw_pf here
243
244        // Coalesce unless it was a software prefetch (see above).
245        if (pkt) {
246            assert(!pkt->isWriteback());
247            // CleanEvicts corresponding to blocks which have
248            // outstanding requests in MSHRs are simply sunk here
249            if (pkt->cmd == MemCmd::CleanEvict) {
250                pendingDelete.reset(pkt);
251            } else if (pkt->cmd == MemCmd::WriteClean) {
252                // A WriteClean should never coalesce with any
253                // outstanding cache maintenance requests.
254
255                // We use forward_time here because there is an
256                // uncached memory write, forwarded to WriteBuffer.
257                allocateWriteBuffer(pkt, forward_time);
258            } else {
259                DPRINTF(Cache, "%s coalescing MSHR for %s\n", __func__,
260                        pkt->print());
261
262                assert(pkt->req->masterId() < system->maxMasters());
263                mshr_hits[pkt->cmdToIndex()][pkt->req->masterId()]++;
264
265                // We use forward_time here because it is the same
266                // considering new targets. We have multiple
267                // requests for the same address here. It
268                // specifies the latency to allocate an internal
269                // buffer and to schedule an event to the queued
270                // port and also takes into account the additional
271                // delay of the xbar.
272                mshr->allocateTarget(pkt, forward_time, order++,
273                                     allocOnFill(pkt->cmd));
274                if (mshr->getNumTargets() == numTarget) {
275                    noTargetMSHR = mshr;
276                    setBlocked(Blocked_NoTargets);
277                    // need to be careful with this... if this mshr isn't
278                    // ready yet (i.e. time > curTick()), we don't want to
279                    // move it ahead of mshrs that are ready
280                    // mshrQueue.moveToFront(mshr);
281                }
282            }
283        }
284    } else {
285        // no MSHR
286        assert(pkt->req->masterId() < system->maxMasters());
287        mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
288
289        if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean) {
290            // We use forward_time here because there is an
291            // writeback or writeclean, forwarded to WriteBuffer.
292            allocateWriteBuffer(pkt, forward_time);
293        } else {
294            if (blk && blk->isValid()) {
295                // If we have a write miss to a valid block, we
296                // need to mark the block non-readable.  Otherwise
297                // if we allow reads while there's an outstanding
298                // write miss, the read could return stale data
299                // out of the cache block... a more aggressive
300                // system could detect the overlap (if any) and
301                // forward data out of the MSHRs, but we don't do
302                // that yet.  Note that we do need to leave the
303                // block valid so that it stays in the cache, in
304                // case we get an upgrade response (and hence no
305                // new data) when the write miss completes.
306                // As long as CPUs do proper store/load forwarding
307                // internally, and have a sufficiently weak memory
308                // model, this is probably unnecessary, but at some
309                // point it must have seemed like we needed it...
310                assert((pkt->needsWritable() && !blk->isWritable()) ||
311                       pkt->req->isCacheMaintenance());
312                blk->status &= ~BlkReadable;
313            }
314            // Here we are using forward_time, modelling the latency of
315            // a miss (outbound) just as forwardLatency, neglecting the
316            // lookupLatency component.
317            allocateMissBuffer(pkt, forward_time);
318        }
319    }
320}
321
322void
323BaseCache::recvTimingReq(PacketPtr pkt)
324{
325    // anything that is merely forwarded pays for the forward latency and
326    // the delay provided by the crossbar
327    Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
328
329    // We use lookupLatency here because it is used to specify the latency
330    // to access.
331    Cycles lat = lookupLatency;
332    CacheBlk *blk = nullptr;
333    bool satisfied = false;
334    {
335        PacketList writebacks;
336        // Note that lat is passed by reference here. The function
337        // access() calls accessBlock() which can modify lat value.
338        satisfied = access(pkt, blk, lat, writebacks);
339
340        // copy writebacks to write buffer here to ensure they logically
341        // proceed anything happening below
342        doWritebacks(writebacks, forward_time);
343    }
344
345    // Here we charge the headerDelay that takes into account the latencies
346    // of the bus, if the packet comes from it.
347    // The latency charged it is just lat that is the value of lookupLatency
348    // modified by access() function, or if not just lookupLatency.
349    // In case of a hit we are neglecting response latency.
350    // In case of a miss we are neglecting forward latency.
351    Tick request_time = clockEdge(lat) + pkt->headerDelay;
352    // Here we reset the timing of the packet.
353    pkt->headerDelay = pkt->payloadDelay = 0;
354    // track time of availability of next prefetch, if any
355    Tick next_pf_time = MaxTick;
356
357    if (satisfied) {
358        // if need to notify the prefetcher we have to do it before
359        // anything else as later handleTimingReqHit might turn the
360        // packet in a response
361        if (prefetcher &&
362            (prefetchOnAccess || (blk && blk->wasPrefetched()))) {
363            if (blk)
364                blk->status &= ~BlkHWPrefetched;
365
366            // Don't notify on SWPrefetch
367            if (!pkt->cmd.isSWPrefetch()) {
368                assert(!pkt->req->isCacheMaintenance());
369                next_pf_time = prefetcher->notify(pkt);
370            }
371        }
372
373        handleTimingReqHit(pkt, blk, request_time);
374    } else {
375        handleTimingReqMiss(pkt, blk, forward_time, request_time);
376
377        // We should call the prefetcher reguardless if the request is
378        // satisfied or not, reguardless if the request is in the MSHR
379        // or not. The request could be a ReadReq hit, but still not
380        // satisfied (potentially because of a prior write to the same
381        // cache line. So, even when not satisfied, there is an MSHR
382        // already allocated for this, we need to let the prefetcher
383        // know about the request
384
385        // Don't notify prefetcher on SWPrefetch or cache maintenance
386        // operations
387        if (prefetcher && pkt &&
388            !pkt->cmd.isSWPrefetch() &&
389            !pkt->req->isCacheMaintenance()) {
390            next_pf_time = prefetcher->notify(pkt);
391        }
392    }
393
394    if (next_pf_time != MaxTick) {
395        schedMemSideSendEvent(next_pf_time);
396    }
397}
398
399void
400BaseCache::handleUncacheableWriteResp(PacketPtr pkt)
401{
402    Tick completion_time = clockEdge(responseLatency) +
403        pkt->headerDelay + pkt->payloadDelay;
404
405    // Reset the bus additional time as it is now accounted for
406    pkt->headerDelay = pkt->payloadDelay = 0;
407
408    cpuSidePort.schedTimingResp(pkt, completion_time, true);
409}
410
411void
412BaseCache::recvTimingResp(PacketPtr pkt)
413{
414    assert(pkt->isResponse());
415
416    // all header delay should be paid for by the crossbar, unless
417    // this is a prefetch response from above
418    panic_if(pkt->headerDelay != 0 && pkt->cmd != MemCmd::HardPFResp,
419             "%s saw a non-zero packet delay\n", name());
420
421    const bool is_error = pkt->isError();
422
423    if (is_error) {
424        DPRINTF(Cache, "%s: Cache received %s with error\n", __func__,
425                pkt->print());
426    }
427
428    DPRINTF(Cache, "%s: Handling response %s\n", __func__,
429            pkt->print());
430
431    // if this is a write, we should be looking at an uncacheable
432    // write
433    if (pkt->isWrite()) {
434        assert(pkt->req->isUncacheable());
435        handleUncacheableWriteResp(pkt);
436        return;
437    }
438
439    // we have dealt with any (uncacheable) writes above, from here on
440    // we know we are dealing with an MSHR due to a miss or a prefetch
441    MSHR *mshr = dynamic_cast<MSHR*>(pkt->popSenderState());
442    assert(mshr);
443
444    if (mshr == noTargetMSHR) {
445        // we always clear at least one target
446        clearBlocked(Blocked_NoTargets);
447        noTargetMSHR = nullptr;
448    }
449
450    // Initial target is used just for stats
451    MSHR::Target *initial_tgt = mshr->getTarget();
452    int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
453    Tick miss_latency = curTick() - initial_tgt->recvTime;
454
455    if (pkt->req->isUncacheable()) {
456        assert(pkt->req->masterId() < system->maxMasters());
457        mshr_uncacheable_lat[stats_cmd_idx][pkt->req->masterId()] +=
458            miss_latency;
459    } else {
460        assert(pkt->req->masterId() < system->maxMasters());
461        mshr_miss_latency[stats_cmd_idx][pkt->req->masterId()] +=
462            miss_latency;
463    }
464
465    PacketList writebacks;
466
467    bool is_fill = !mshr->isForward &&
468        (pkt->isRead() || pkt->cmd == MemCmd::UpgradeResp);
469
470    CacheBlk *blk = tags->findBlock(pkt->getAddr(), pkt->isSecure());
471
472    if (is_fill && !is_error) {
473        DPRINTF(Cache, "Block for addr %#llx being updated in Cache\n",
474                pkt->getAddr());
475
476        blk = handleFill(pkt, blk, writebacks, mshr->allocOnFill());
477        assert(blk != nullptr);
478    }
479
480    if (blk && blk->isValid() && pkt->isClean() && !pkt->isInvalidate()) {
481        // The block was marked not readable while there was a pending
482        // cache maintenance operation, restore its flag.
483        blk->status |= BlkReadable;
484    }
485
486    if (blk && blk->isWritable() && !pkt->req->isCacheInvalidate()) {
487        // If at this point the referenced block is writable and the
488        // response is not a cache invalidate, we promote targets that
489        // were deferred as we couldn't guarrantee a writable copy
490        mshr->promoteWritable();
491    }
492
493    serviceMSHRTargets(mshr, pkt, blk, writebacks);
494
495    if (mshr->promoteDeferredTargets()) {
496        // avoid later read getting stale data while write miss is
497        // outstanding.. see comment in timingAccess()
498        if (blk) {
499            blk->status &= ~BlkReadable;
500        }
501        mshrQueue.markPending(mshr);
502        schedMemSideSendEvent(clockEdge() + pkt->payloadDelay);
503    } else {
504        // while we deallocate an mshr from the queue we still have to
505        // check the isFull condition before and after as we might
506        // have been using the reserved entries already
507        const bool was_full = mshrQueue.isFull();
508        mshrQueue.deallocate(mshr);
509        if (was_full && !mshrQueue.isFull()) {
510            clearBlocked(Blocked_NoMSHRs);
511        }
512
513        // Request the bus for a prefetch if this deallocation freed enough
514        // MSHRs for a prefetch to take place
515        if (prefetcher && mshrQueue.canPrefetch()) {
516            Tick next_pf_time = std::max(prefetcher->nextPrefetchReadyTime(),
517                                         clockEdge());
518            if (next_pf_time != MaxTick)
519                schedMemSideSendEvent(next_pf_time);
520        }
521    }
522
523    // if we used temp block, check to see if its valid and then clear it out
524    if (blk == tempBlock && tempBlock->isValid()) {
525        evictBlock(blk, writebacks);
526    }
527
528    const Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
529    // copy writebacks to write buffer
530    doWritebacks(writebacks, forward_time);
531
532    DPRINTF(CacheVerbose, "%s: Leaving with %s\n", __func__, pkt->print());
533    delete pkt;
534}
535
536
537Tick
538BaseCache::recvAtomic(PacketPtr pkt)
539{
540    // We are in atomic mode so we pay just for lookupLatency here.
541    Cycles lat = lookupLatency;
542
543    // follow the same flow as in recvTimingReq, and check if a cache
544    // above us is responding
545    if (pkt->cacheResponding() && !pkt->isClean()) {
546        assert(!pkt->req->isCacheInvalidate());
547        DPRINTF(Cache, "Cache above responding to %s: not responding\n",
548                pkt->print());
549
550        // if a cache is responding, and it had the line in Owned
551        // rather than Modified state, we need to invalidate any
552        // copies that are not on the same path to memory
553        assert(pkt->needsWritable() && !pkt->responderHadWritable());
554        lat += ticksToCycles(memSidePort.sendAtomic(pkt));
555
556        return lat * clockPeriod();
557    }
558
559    // should assert here that there are no outstanding MSHRs or
560    // writebacks... that would mean that someone used an atomic
561    // access in timing mode
562
563    CacheBlk *blk = nullptr;
564    PacketList writebacks;
565    bool satisfied = access(pkt, blk, lat, writebacks);
566
567    if (pkt->isClean() && blk && blk->isDirty()) {
568        // A cache clean opearation is looking for a dirty
569        // block. If a dirty block is encountered a WriteClean
570        // will update any copies to the path to the memory
571        // until the point of reference.
572        DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
573                __func__, pkt->print(), blk->print());
574        PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(), pkt->id);
575        writebacks.push_back(wb_pkt);
576        pkt->setSatisfied();
577    }
578
579    // handle writebacks resulting from the access here to ensure they
580    // logically proceed anything happening below
581    doWritebacksAtomic(writebacks);
582    assert(writebacks.empty());
583
584    if (!satisfied) {
585        lat += handleAtomicReqMiss(pkt, blk, writebacks);
586    }
587
588    // Note that we don't invoke the prefetcher at all in atomic mode.
589    // It's not clear how to do it properly, particularly for
590    // prefetchers that aggressively generate prefetch candidates and
591    // rely on bandwidth contention to throttle them; these will tend
592    // to pollute the cache in atomic mode since there is no bandwidth
593    // contention.  If we ever do want to enable prefetching in atomic
594    // mode, though, this is the place to do it... see timingAccess()
595    // for an example (though we'd want to issue the prefetch(es)
596    // immediately rather than calling requestMemSideBus() as we do
597    // there).
598
599    // do any writebacks resulting from the response handling
600    doWritebacksAtomic(writebacks);
601
602    // if we used temp block, check to see if its valid and if so
603    // clear it out, but only do so after the call to recvAtomic is
604    // finished so that any downstream observers (such as a snoop
605    // filter), first see the fill, and only then see the eviction
606    if (blk == tempBlock && tempBlock->isValid()) {
607        // the atomic CPU calls recvAtomic for fetch and load/store
608        // sequentuially, and we may already have a tempBlock
609        // writeback from the fetch that we have not yet sent
610        if (tempBlockWriteback) {
611            // if that is the case, write the prevoius one back, and
612            // do not schedule any new event
613            writebackTempBlockAtomic();
614        } else {
615            // the writeback/clean eviction happens after the call to
616            // recvAtomic has finished (but before any successive
617            // calls), so that the response handling from the fill is
618            // allowed to happen first
619            schedule(writebackTempBlockAtomicEvent, curTick());
620        }
621
622        tempBlockWriteback = evictBlock(blk);
623    }
624
625    if (pkt->needsResponse()) {
626        pkt->makeAtomicResponse();
627    }
628
629    return lat * clockPeriod();
630}
631
632void
633BaseCache::functionalAccess(PacketPtr pkt, bool from_cpu_side)
634{
635    Addr blk_addr = pkt->getBlockAddr(blkSize);
636    bool is_secure = pkt->isSecure();
637    CacheBlk *blk = tags->findBlock(pkt->getAddr(), is_secure);
638    MSHR *mshr = mshrQueue.findMatch(blk_addr, is_secure);
639
640    pkt->pushLabel(name());
641
642    CacheBlkPrintWrapper cbpw(blk);
643
644    // Note that just because an L2/L3 has valid data doesn't mean an
645    // L1 doesn't have a more up-to-date modified copy that still
646    // needs to be found.  As a result we always update the request if
647    // we have it, but only declare it satisfied if we are the owner.
648
649    // see if we have data at all (owned or otherwise)
650    bool have_data = blk && blk->isValid()
651        && pkt->checkFunctional(&cbpw, blk_addr, is_secure, blkSize,
652                                blk->data);
653
654    // data we have is dirty if marked as such or if we have an
655    // in-service MSHR that is pending a modified line
656    bool have_dirty =
657        have_data && (blk->isDirty() ||
658                      (mshr && mshr->inService && mshr->isPendingModified()));
659
660    bool done = have_dirty ||
661        cpuSidePort.checkFunctional(pkt) ||
662        mshrQueue.checkFunctional(pkt, blk_addr) ||
663        writeBuffer.checkFunctional(pkt, blk_addr) ||
664        memSidePort.checkFunctional(pkt);
665
666    DPRINTF(CacheVerbose, "%s: %s %s%s%s\n", __func__,  pkt->print(),
667            (blk && blk->isValid()) ? "valid " : "",
668            have_data ? "data " : "", done ? "done " : "");
669
670    // We're leaving the cache, so pop cache->name() label
671    pkt->popLabel();
672
673    if (done) {
674        pkt->makeResponse();
675    } else {
676        // if it came as a request from the CPU side then make sure it
677        // continues towards the memory side
678        if (from_cpu_side) {
679            memSidePort.sendFunctional(pkt);
680        } else if (cpuSidePort.isSnooping()) {
681            // if it came from the memory side, it must be a snoop request
682            // and we should only forward it if we are forwarding snoops
683            cpuSidePort.sendFunctionalSnoop(pkt);
684        }
685    }
686}
687
688
689void
690BaseCache::cmpAndSwap(CacheBlk *blk, PacketPtr pkt)
691{
692    assert(pkt->isRequest());
693
694    uint64_t overwrite_val;
695    bool overwrite_mem;
696    uint64_t condition_val64;
697    uint32_t condition_val32;
698
699    int offset = pkt->getOffset(blkSize);
700    uint8_t *blk_data = blk->data + offset;
701
702    assert(sizeof(uint64_t) >= pkt->getSize());
703
704    overwrite_mem = true;
705    // keep a copy of our possible write value, and copy what is at the
706    // memory address into the packet
707    pkt->writeData((uint8_t *)&overwrite_val);
708    pkt->setData(blk_data);
709
710    if (pkt->req->isCondSwap()) {
711        if (pkt->getSize() == sizeof(uint64_t)) {
712            condition_val64 = pkt->req->getExtraData();
713            overwrite_mem = !std::memcmp(&condition_val64, blk_data,
714                                         sizeof(uint64_t));
715        } else if (pkt->getSize() == sizeof(uint32_t)) {
716            condition_val32 = (uint32_t)pkt->req->getExtraData();
717            overwrite_mem = !std::memcmp(&condition_val32, blk_data,
718                                         sizeof(uint32_t));
719        } else
720            panic("Invalid size for conditional read/write\n");
721    }
722
723    if (overwrite_mem) {
724        std::memcpy(blk_data, &overwrite_val, pkt->getSize());
725        blk->status |= BlkDirty;
726    }
727}
728
729QueueEntry*
730BaseCache::getNextQueueEntry()
731{
732    // Check both MSHR queue and write buffer for potential requests,
733    // note that null does not mean there is no request, it could
734    // simply be that it is not ready
735    MSHR *miss_mshr  = mshrQueue.getNext();
736    WriteQueueEntry *wq_entry = writeBuffer.getNext();
737
738    // If we got a write buffer request ready, first priority is a
739    // full write buffer, otherwise we favour the miss requests
740    if (wq_entry && (writeBuffer.isFull() || !miss_mshr)) {
741        // need to search MSHR queue for conflicting earlier miss.
742        MSHR *conflict_mshr =
743            mshrQueue.findPending(wq_entry->blkAddr,
744                                  wq_entry->isSecure);
745
746        if (conflict_mshr && conflict_mshr->order < wq_entry->order) {
747            // Service misses in order until conflict is cleared.
748            return conflict_mshr;
749
750            // @todo Note that we ignore the ready time of the conflict here
751        }
752
753        // No conflicts; issue write
754        return wq_entry;
755    } else if (miss_mshr) {
756        // need to check for conflicting earlier writeback
757        WriteQueueEntry *conflict_mshr =
758            writeBuffer.findPending(miss_mshr->blkAddr,
759                                    miss_mshr->isSecure);
760        if (conflict_mshr) {
761            // not sure why we don't check order here... it was in the
762            // original code but commented out.
763
764            // The only way this happens is if we are
765            // doing a write and we didn't have permissions
766            // then subsequently saw a writeback (owned got evicted)
767            // We need to make sure to perform the writeback first
768            // To preserve the dirty data, then we can issue the write
769
770            // should we return wq_entry here instead?  I.e. do we
771            // have to flush writes in order?  I don't think so... not
772            // for Alpha anyway.  Maybe for x86?
773            return conflict_mshr;
774
775            // @todo Note that we ignore the ready time of the conflict here
776        }
777
778        // No conflicts; issue read
779        return miss_mshr;
780    }
781
782    // fall through... no pending requests.  Try a prefetch.
783    assert(!miss_mshr && !wq_entry);
784    if (prefetcher && mshrQueue.canPrefetch()) {
785        // If we have a miss queue slot, we can try a prefetch
786        PacketPtr pkt = prefetcher->getPacket();
787        if (pkt) {
788            Addr pf_addr = pkt->getBlockAddr(blkSize);
789            if (!tags->findBlock(pf_addr, pkt->isSecure()) &&
790                !mshrQueue.findMatch(pf_addr, pkt->isSecure()) &&
791                !writeBuffer.findMatch(pf_addr, pkt->isSecure())) {
792                // Update statistic on number of prefetches issued
793                // (hwpf_mshr_misses)
794                assert(pkt->req->masterId() < system->maxMasters());
795                mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
796
797                // allocate an MSHR and return it, note
798                // that we send the packet straight away, so do not
799                // schedule the send
800                return allocateMissBuffer(pkt, curTick(), false);
801            } else {
802                // free the request and packet
803                delete pkt->req;
804                delete pkt;
805            }
806        }
807    }
808
809    return nullptr;
810}
811
812void
813BaseCache::satisfyRequest(PacketPtr pkt, CacheBlk *blk, bool, bool)
814{
815    assert(pkt->isRequest());
816
817    assert(blk && blk->isValid());
818    // Occasionally this is not true... if we are a lower-level cache
819    // satisfying a string of Read and ReadEx requests from
820    // upper-level caches, a Read will mark the block as shared but we
821    // can satisfy a following ReadEx anyway since we can rely on the
822    // Read requester(s) to have buffered the ReadEx snoop and to
823    // invalidate their blocks after receiving them.
824    // assert(!pkt->needsWritable() || blk->isWritable());
825    assert(pkt->getOffset(blkSize) + pkt->getSize() <= blkSize);
826
827    // Check RMW operations first since both isRead() and
828    // isWrite() will be true for them
829    if (pkt->cmd == MemCmd::SwapReq) {
830        cmpAndSwap(blk, pkt);
831    } else if (pkt->isWrite()) {
832        // we have the block in a writable state and can go ahead,
833        // note that the line may be also be considered writable in
834        // downstream caches along the path to memory, but always
835        // Exclusive, and never Modified
836        assert(blk->isWritable());
837        // Write or WriteLine at the first cache with block in writable state
838        if (blk->checkWrite(pkt)) {
839            pkt->writeDataToBlock(blk->data, blkSize);
840        }
841        // Always mark the line as dirty (and thus transition to the
842        // Modified state) even if we are a failed StoreCond so we
843        // supply data to any snoops that have appended themselves to
844        // this cache before knowing the store will fail.
845        blk->status |= BlkDirty;
846        DPRINTF(CacheVerbose, "%s for %s (write)\n", __func__, pkt->print());
847    } else if (pkt->isRead()) {
848        if (pkt->isLLSC()) {
849            blk->trackLoadLocked(pkt);
850        }
851
852        // all read responses have a data payload
853        assert(pkt->hasRespData());
854        pkt->setDataFromBlock(blk->data, blkSize);
855    } else if (pkt->isUpgrade()) {
856        // sanity check
857        assert(!pkt->hasSharers());
858
859        if (blk->isDirty()) {
860            // we were in the Owned state, and a cache above us that
861            // has the line in Shared state needs to be made aware
862            // that the data it already has is in fact dirty
863            pkt->setCacheResponding();
864            blk->status &= ~BlkDirty;
865        }
866    } else {
867        assert(pkt->isInvalidate());
868        invalidateBlock(blk);
869        DPRINTF(CacheVerbose, "%s for %s (invalidation)\n", __func__,
870                pkt->print());
871    }
872}
873
874/////////////////////////////////////////////////////
875//
876// Access path: requests coming in from the CPU side
877//
878/////////////////////////////////////////////////////
879
880bool
881BaseCache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
882                  PacketList &writebacks)
883{
884    // sanity check
885    assert(pkt->isRequest());
886
887    chatty_assert(!(isReadOnly && pkt->isWrite()),
888                  "Should never see a write in a read-only cache %s\n",
889                  name());
890
891    // Here lat is the value passed as parameter to accessBlock() function
892    // that can modify its value.
893    blk = tags->accessBlock(pkt->getAddr(), pkt->isSecure(), lat);
894
895    DPRINTF(Cache, "%s for %s %s\n", __func__, pkt->print(),
896            blk ? "hit " + blk->print() : "miss");
897
898    if (pkt->req->isCacheMaintenance()) {
899        // A cache maintenance operation is always forwarded to the
900        // memory below even if the block is found in dirty state.
901
902        // We defer any changes to the state of the block until we
903        // create and mark as in service the mshr for the downstream
904        // packet.
905        return false;
906    }
907
908    if (pkt->isEviction()) {
909        // We check for presence of block in above caches before issuing
910        // Writeback or CleanEvict to write buffer. Therefore the only
911        // possible cases can be of a CleanEvict packet coming from above
912        // encountering a Writeback generated in this cache peer cache and
913        // waiting in the write buffer. Cases of upper level peer caches
914        // generating CleanEvict and Writeback or simply CleanEvict and
915        // CleanEvict almost simultaneously will be caught by snoops sent out
916        // by crossbar.
917        WriteQueueEntry *wb_entry = writeBuffer.findMatch(pkt->getAddr(),
918                                                          pkt->isSecure());
919        if (wb_entry) {
920            assert(wb_entry->getNumTargets() == 1);
921            PacketPtr wbPkt = wb_entry->getTarget()->pkt;
922            assert(wbPkt->isWriteback());
923
924            if (pkt->isCleanEviction()) {
925                // The CleanEvict and WritebackClean snoops into other
926                // peer caches of the same level while traversing the
927                // crossbar. If a copy of the block is found, the
928                // packet is deleted in the crossbar. Hence, none of
929                // the other upper level caches connected to this
930                // cache have the block, so we can clear the
931                // BLOCK_CACHED flag in the Writeback if set and
932                // discard the CleanEvict by returning true.
933                wbPkt->clearBlockCached();
934                return true;
935            } else {
936                assert(pkt->cmd == MemCmd::WritebackDirty);
937                // Dirty writeback from above trumps our clean
938                // writeback... discard here
939                // Note: markInService will remove entry from writeback buffer.
940                markInService(wb_entry);
941                delete wbPkt;
942            }
943        }
944    }
945
946    // Writeback handling is special case.  We can write the block into
947    // the cache without having a writeable copy (or any copy at all).
948    if (pkt->isWriteback()) {
949        assert(blkSize == pkt->getSize());
950
951        // we could get a clean writeback while we are having
952        // outstanding accesses to a block, do the simple thing for
953        // now and drop the clean writeback so that we do not upset
954        // any ordering/decisions about ownership already taken
955        if (pkt->cmd == MemCmd::WritebackClean &&
956            mshrQueue.findMatch(pkt->getAddr(), pkt->isSecure())) {
957            DPRINTF(Cache, "Clean writeback %#llx to block with MSHR, "
958                    "dropping\n", pkt->getAddr());
959            return true;
960        }
961
962        if (!blk) {
963            // need to do a replacement
964            blk = allocateBlock(pkt->getAddr(), pkt->isSecure(), writebacks);
965            if (!blk) {
966                // no replaceable block available: give up, fwd to next level.
967                incMissCount(pkt);
968                return false;
969            }
970            tags->insertBlock(pkt, blk);
971
972            blk->status |= (BlkValid | BlkReadable);
973        }
974        // only mark the block dirty if we got a writeback command,
975        // and leave it as is for a clean writeback
976        if (pkt->cmd == MemCmd::WritebackDirty) {
977            // TODO: the coherent cache can assert(!blk->isDirty());
978            blk->status |= BlkDirty;
979        }
980        // if the packet does not have sharers, it is passing
981        // writable, and we got the writeback in Modified or Exclusive
982        // state, if not we are in the Owned or Shared state
983        if (!pkt->hasSharers()) {
984            blk->status |= BlkWritable;
985        }
986        // nothing else to do; writeback doesn't expect response
987        assert(!pkt->needsResponse());
988        pkt->writeDataToBlock(blk->data, blkSize);
989        DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
990        incHitCount(pkt);
991        // populate the time when the block will be ready to access.
992        blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
993            pkt->payloadDelay;
994        return true;
995    } else if (pkt->cmd == MemCmd::CleanEvict) {
996        if (blk) {
997            // Found the block in the tags, need to stop CleanEvict from
998            // propagating further down the hierarchy. Returning true will
999            // treat the CleanEvict like a satisfied write request and delete
1000            // it.
1001            return true;
1002        }
1003        // We didn't find the block here, propagate the CleanEvict further
1004        // down the memory hierarchy. Returning false will treat the CleanEvict
1005        // like a Writeback which could not find a replaceable block so has to
1006        // go to next level.
1007        return false;
1008    } else if (pkt->cmd == MemCmd::WriteClean) {
1009        // WriteClean handling is a special case. We can allocate a
1010        // block directly if it doesn't exist and we can update the
1011        // block immediately. The WriteClean transfers the ownership
1012        // of the block as well.
1013        assert(blkSize == pkt->getSize());
1014
1015        if (!blk) {
1016            if (pkt->writeThrough()) {
1017                // if this is a write through packet, we don't try to
1018                // allocate if the block is not present
1019                return false;
1020            } else {
1021                // a writeback that misses needs to allocate a new block
1022                blk = allocateBlock(pkt->getAddr(), pkt->isSecure(),
1023                                    writebacks);
1024                if (!blk) {
1025                    // no replaceable block available: give up, fwd to
1026                    // next level.
1027                    incMissCount(pkt);
1028                    return false;
1029                }
1030                tags->insertBlock(pkt, blk);
1031
1032                blk->status |= (BlkValid | BlkReadable);
1033            }
1034        }
1035
1036        // at this point either this is a writeback or a write-through
1037        // write clean operation and the block is already in this
1038        // cache, we need to update the data and the block flags
1039        assert(blk);
1040        // TODO: the coherent cache can assert(!blk->isDirty());
1041        if (!pkt->writeThrough()) {
1042            blk->status |= BlkDirty;
1043        }
1044        // nothing else to do; writeback doesn't expect response
1045        assert(!pkt->needsResponse());
1046        pkt->writeDataToBlock(blk->data, blkSize);
1047        DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1048
1049        incHitCount(pkt);
1050        // populate the time when the block will be ready to access.
1051        blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1052            pkt->payloadDelay;
1053        // if this a write-through packet it will be sent to cache
1054        // below
1055        return !pkt->writeThrough();
1056    } else if (blk && (pkt->needsWritable() ? blk->isWritable() :
1057                       blk->isReadable())) {
1058        // OK to satisfy access
1059        incHitCount(pkt);
1060        satisfyRequest(pkt, blk);
1061        maintainClusivity(pkt->fromCache(), blk);
1062
1063        return true;
1064    }
1065
1066    // Can't satisfy access normally... either no block (blk == nullptr)
1067    // or have block but need writable
1068
1069    incMissCount(pkt);
1070
1071    if (!blk && pkt->isLLSC() && pkt->isWrite()) {
1072        // complete miss on store conditional... just give up now
1073        pkt->req->setExtraData(0);
1074        return true;
1075    }
1076
1077    return false;
1078}
1079
1080void
1081BaseCache::maintainClusivity(bool from_cache, CacheBlk *blk)
1082{
1083    if (from_cache && blk && blk->isValid() && !blk->isDirty() &&
1084        clusivity == Enums::mostly_excl) {
1085        // if we have responded to a cache, and our block is still
1086        // valid, but not dirty, and this cache is mostly exclusive
1087        // with respect to the cache above, drop the block
1088        invalidateBlock(blk);
1089    }
1090}
1091
1092CacheBlk*
1093BaseCache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks,
1094                      bool allocate)
1095{
1096    assert(pkt->isResponse() || pkt->cmd == MemCmd::WriteLineReq);
1097    Addr addr = pkt->getAddr();
1098    bool is_secure = pkt->isSecure();
1099#if TRACING_ON
1100    CacheBlk::State old_state = blk ? blk->status : 0;
1101#endif
1102
1103    // When handling a fill, we should have no writes to this line.
1104    assert(addr == pkt->getBlockAddr(blkSize));
1105    assert(!writeBuffer.findMatch(addr, is_secure));
1106
1107    if (!blk) {
1108        // better have read new data...
1109        assert(pkt->hasData());
1110
1111        // only read responses and write-line requests have data;
1112        // note that we don't write the data here for write-line - that
1113        // happens in the subsequent call to satisfyRequest
1114        assert(pkt->isRead() || pkt->cmd == MemCmd::WriteLineReq);
1115
1116        // need to do a replacement if allocating, otherwise we stick
1117        // with the temporary storage
1118        blk = allocate ? allocateBlock(addr, is_secure, writebacks) : nullptr;
1119
1120        if (!blk) {
1121            // No replaceable block or a mostly exclusive
1122            // cache... just use temporary storage to complete the
1123            // current request and then get rid of it
1124            assert(!tempBlock->isValid());
1125            blk = tempBlock;
1126            tempBlock->set = tags->extractSet(addr);
1127            tempBlock->tag = tags->extractTag(addr);
1128            DPRINTF(Cache, "using temp block for %#llx (%s)\n", addr,
1129                    is_secure ? "s" : "ns");
1130        } else {
1131            tags->insertBlock(pkt, blk);
1132        }
1133
1134        // we should never be overwriting a valid block
1135        assert(!blk->isValid());
1136    } else {
1137        // existing block... probably an upgrade
1138        assert(blk->tag == tags->extractTag(addr));
1139        assert(blk->isSecure() == is_secure);
1140        // either we're getting new data or the block should already be valid
1141        assert(pkt->hasData() || blk->isValid());
1142        // don't clear block status... if block is already dirty we
1143        // don't want to lose that
1144    }
1145
1146    blk->status |= BlkValid | BlkReadable;
1147
1148    // sanity check for whole-line writes, which should always be
1149    // marked as writable as part of the fill, and then later marked
1150    // dirty as part of satisfyRequest
1151    if (pkt->cmd == MemCmd::WriteLineReq) {
1152        assert(!pkt->hasSharers());
1153    }
1154
1155    // here we deal with setting the appropriate state of the line,
1156    // and we start by looking at the hasSharers flag, and ignore the
1157    // cacheResponding flag (normally signalling dirty data) if the
1158    // packet has sharers, thus the line is never allocated as Owned
1159    // (dirty but not writable), and always ends up being either
1160    // Shared, Exclusive or Modified, see Packet::setCacheResponding
1161    // for more details
1162    if (!pkt->hasSharers()) {
1163        // we could get a writable line from memory (rather than a
1164        // cache) even in a read-only cache, note that we set this bit
1165        // even for a read-only cache, possibly revisit this decision
1166        blk->status |= BlkWritable;
1167
1168        // check if we got this via cache-to-cache transfer (i.e., from a
1169        // cache that had the block in Modified or Owned state)
1170        if (pkt->cacheResponding()) {
1171            // we got the block in Modified state, and invalidated the
1172            // owners copy
1173            blk->status |= BlkDirty;
1174
1175            chatty_assert(!isReadOnly, "Should never see dirty snoop response "
1176                          "in read-only cache %s\n", name());
1177        }
1178    }
1179
1180    DPRINTF(Cache, "Block addr %#llx (%s) moving from state %x to %s\n",
1181            addr, is_secure ? "s" : "ns", old_state, blk->print());
1182
1183    // if we got new data, copy it in (checking for a read response
1184    // and a response that has data is the same in the end)
1185    if (pkt->isRead()) {
1186        // sanity checks
1187        assert(pkt->hasData());
1188        assert(pkt->getSize() == blkSize);
1189
1190        pkt->writeDataToBlock(blk->data, blkSize);
1191    }
1192    // We pay for fillLatency here.
1193    blk->whenReady = clockEdge() + fillLatency * clockPeriod() +
1194        pkt->payloadDelay;
1195
1196    return blk;
1197}
1198
1199CacheBlk*
1200BaseCache::allocateBlock(Addr addr, bool is_secure, PacketList &writebacks)
1201{
1202    // Find replacement victim
1203    CacheBlk *blk = tags->findVictim(addr);
1204
1205    // It is valid to return nullptr if there is no victim
1206    if (!blk)
1207        return nullptr;
1208
1209    if (blk->isValid()) {
1210        Addr repl_addr = tags->regenerateBlkAddr(blk);
1211        MSHR *repl_mshr = mshrQueue.findMatch(repl_addr, blk->isSecure());
1212        if (repl_mshr) {
1213            // must be an outstanding upgrade or clean request
1214            // on a block we're about to replace...
1215            assert((!blk->isWritable() && repl_mshr->needsWritable()) ||
1216                   repl_mshr->isCleaning());
1217            // too hard to replace block with transient state
1218            // allocation failed, block not inserted
1219            return nullptr;
1220        } else {
1221            DPRINTF(Cache, "replacement: replacing %#llx (%s) with %#llx "
1222                    "(%s): %s\n", repl_addr, blk->isSecure() ? "s" : "ns",
1223                    addr, is_secure ? "s" : "ns",
1224                    blk->isDirty() ? "writeback" : "clean");
1225
1226            if (blk->wasPrefetched()) {
1227                unusedPrefetches++;
1228            }
1229            evictBlock(blk, writebacks);
1230            replacements++;
1231        }
1232    }
1233
1234    return blk;
1235}
1236
1237void
1238BaseCache::invalidateBlock(CacheBlk *blk)
1239{
1240    if (blk != tempBlock)
1241        tags->invalidate(blk);
1242    blk->invalidate();
1243}
1244
1245PacketPtr
1246BaseCache::writebackBlk(CacheBlk *blk)
1247{
1248    chatty_assert(!isReadOnly || writebackClean,
1249                  "Writeback from read-only cache");
1250    assert(blk && blk->isValid() && (blk->isDirty() || writebackClean));
1251
1252    writebacks[Request::wbMasterId]++;
1253
1254    Request *req = new Request(tags->regenerateBlkAddr(blk), blkSize, 0,
1255                               Request::wbMasterId);
1256    if (blk->isSecure())
1257        req->setFlags(Request::SECURE);
1258
1259    req->taskId(blk->task_id);
1260
1261    PacketPtr pkt =
1262        new Packet(req, blk->isDirty() ?
1263                   MemCmd::WritebackDirty : MemCmd::WritebackClean);
1264
1265    DPRINTF(Cache, "Create Writeback %s writable: %d, dirty: %d\n",
1266            pkt->print(), blk->isWritable(), blk->isDirty());
1267
1268    if (blk->isWritable()) {
1269        // not asserting shared means we pass the block in modified
1270        // state, mark our own block non-writeable
1271        blk->status &= ~BlkWritable;
1272    } else {
1273        // we are in the Owned state, tell the receiver
1274        pkt->setHasSharers();
1275    }
1276
1277    // make sure the block is not marked dirty
1278    blk->status &= ~BlkDirty;
1279
1280    pkt->allocate();
1281    pkt->setDataFromBlock(blk->data, blkSize);
1282
1283    return pkt;
1284}
1285
1286PacketPtr
1287BaseCache::writecleanBlk(CacheBlk *blk, Request::Flags dest, PacketId id)
1288{
1289    Request *req = new Request(tags->regenerateBlkAddr(blk), blkSize, 0,
1290                               Request::wbMasterId);
1291    if (blk->isSecure()) {
1292        req->setFlags(Request::SECURE);
1293    }
1294    req->taskId(blk->task_id);
1295
1296    PacketPtr pkt = new Packet(req, MemCmd::WriteClean, blkSize, id);
1297
1298    if (dest) {
1299        req->setFlags(dest);
1300        pkt->setWriteThrough();
1301    }
1302
1303    DPRINTF(Cache, "Create %s writable: %d, dirty: %d\n", pkt->print(),
1304            blk->isWritable(), blk->isDirty());
1305
1306    if (blk->isWritable()) {
1307        // not asserting shared means we pass the block in modified
1308        // state, mark our own block non-writeable
1309        blk->status &= ~BlkWritable;
1310    } else {
1311        // we are in the Owned state, tell the receiver
1312        pkt->setHasSharers();
1313    }
1314
1315    // make sure the block is not marked dirty
1316    blk->status &= ~BlkDirty;
1317
1318    pkt->allocate();
1319    pkt->setDataFromBlock(blk->data, blkSize);
1320
1321    return pkt;
1322}
1323
1324
1325void
1326BaseCache::memWriteback()
1327{
1328    tags->forEachBlk([this](CacheBlk &blk) { writebackVisitor(blk); });
1329}
1330
1331void
1332BaseCache::memInvalidate()
1333{
1334    tags->forEachBlk([this](CacheBlk &blk) { invalidateVisitor(blk); });
1335}
1336
1337bool
1338BaseCache::isDirty() const
1339{
1340    return tags->anyBlk([](CacheBlk &blk) { return blk.isDirty(); });
1341}
1342
1343void
1344BaseCache::writebackVisitor(CacheBlk &blk)
1345{
1346    if (blk.isDirty()) {
1347        assert(blk.isValid());
1348
1349        Request request(tags->regenerateBlkAddr(&blk),
1350                        blkSize, 0, Request::funcMasterId);
1351        request.taskId(blk.task_id);
1352        if (blk.isSecure()) {
1353            request.setFlags(Request::SECURE);
1354        }
1355
1356        Packet packet(&request, MemCmd::WriteReq);
1357        packet.dataStatic(blk.data);
1358
1359        memSidePort.sendFunctional(&packet);
1360
1361        blk.status &= ~BlkDirty;
1362    }
1363}
1364
1365void
1366BaseCache::invalidateVisitor(CacheBlk &blk)
1367{
1368    if (blk.isDirty())
1369        warn_once("Invalidating dirty cache lines. " \
1370                  "Expect things to break.\n");
1371
1372    if (blk.isValid()) {
1373        assert(!blk.isDirty());
1374        invalidateBlock(&blk);
1375    }
1376}
1377
1378Tick
1379BaseCache::nextQueueReadyTime() const
1380{
1381    Tick nextReady = std::min(mshrQueue.nextReadyTime(),
1382                              writeBuffer.nextReadyTime());
1383
1384    // Don't signal prefetch ready time if no MSHRs available
1385    // Will signal once enoguh MSHRs are deallocated
1386    if (prefetcher && mshrQueue.canPrefetch()) {
1387        nextReady = std::min(nextReady,
1388                             prefetcher->nextPrefetchReadyTime());
1389    }
1390
1391    return nextReady;
1392}
1393
1394
1395bool
1396BaseCache::sendMSHRQueuePacket(MSHR* mshr)
1397{
1398    assert(mshr);
1399
1400    // use request from 1st target
1401    PacketPtr tgt_pkt = mshr->getTarget()->pkt;
1402
1403    DPRINTF(Cache, "%s: MSHR %s\n", __func__, tgt_pkt->print());
1404
1405    CacheBlk *blk = tags->findBlock(mshr->blkAddr, mshr->isSecure);
1406
1407    // either a prefetch that is not present upstream, or a normal
1408    // MSHR request, proceed to get the packet to send downstream
1409    PacketPtr pkt = createMissPacket(tgt_pkt, blk, mshr->needsWritable());
1410
1411    mshr->isForward = (pkt == nullptr);
1412
1413    if (mshr->isForward) {
1414        // not a cache block request, but a response is expected
1415        // make copy of current packet to forward, keep current
1416        // copy for response handling
1417        pkt = new Packet(tgt_pkt, false, true);
1418        assert(!pkt->isWrite());
1419    }
1420
1421    // play it safe and append (rather than set) the sender state,
1422    // as forwarded packets may already have existing state
1423    pkt->pushSenderState(mshr);
1424
1425    if (pkt->isClean() && blk && blk->isDirty()) {
1426        // A cache clean opearation is looking for a dirty block. Mark
1427        // the packet so that the destination xbar can determine that
1428        // there will be a follow-up write packet as well.
1429        pkt->setSatisfied();
1430    }
1431
1432    if (!memSidePort.sendTimingReq(pkt)) {
1433        // we are awaiting a retry, but we
1434        // delete the packet and will be creating a new packet
1435        // when we get the opportunity
1436        delete pkt;
1437
1438        // note that we have now masked any requestBus and
1439        // schedSendEvent (we will wait for a retry before
1440        // doing anything), and this is so even if we do not
1441        // care about this packet and might override it before
1442        // it gets retried
1443        return true;
1444    } else {
1445        // As part of the call to sendTimingReq the packet is
1446        // forwarded to all neighbouring caches (and any caches
1447        // above them) as a snoop. Thus at this point we know if
1448        // any of the neighbouring caches are responding, and if
1449        // so, we know it is dirty, and we can determine if it is
1450        // being passed as Modified, making our MSHR the ordering
1451        // point
1452        bool pending_modified_resp = !pkt->hasSharers() &&
1453            pkt->cacheResponding();
1454        markInService(mshr, pending_modified_resp);
1455
1456        if (pkt->isClean() && blk && blk->isDirty()) {
1457            // A cache clean opearation is looking for a dirty
1458            // block. If a dirty block is encountered a WriteClean
1459            // will update any copies to the path to the memory
1460            // until the point of reference.
1461            DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
1462                    __func__, pkt->print(), blk->print());
1463            PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(),
1464                                             pkt->id);
1465            PacketList writebacks;
1466            writebacks.push_back(wb_pkt);
1467            doWritebacks(writebacks, 0);
1468        }
1469
1470        return false;
1471    }
1472}
1473
1474bool
1475BaseCache::sendWriteQueuePacket(WriteQueueEntry* wq_entry)
1476{
1477    assert(wq_entry);
1478
1479    // always a single target for write queue entries
1480    PacketPtr tgt_pkt = wq_entry->getTarget()->pkt;
1481
1482    DPRINTF(Cache, "%s: write %s\n", __func__, tgt_pkt->print());
1483
1484    // forward as is, both for evictions and uncacheable writes
1485    if (!memSidePort.sendTimingReq(tgt_pkt)) {
1486        // note that we have now masked any requestBus and
1487        // schedSendEvent (we will wait for a retry before
1488        // doing anything), and this is so even if we do not
1489        // care about this packet and might override it before
1490        // it gets retried
1491        return true;
1492    } else {
1493        markInService(wq_entry);
1494        return false;
1495    }
1496}
1497
1498void
1499BaseCache::serialize(CheckpointOut &cp) const
1500{
1501    bool dirty(isDirty());
1502
1503    if (dirty) {
1504        warn("*** The cache still contains dirty data. ***\n");
1505        warn("    Make sure to drain the system using the correct flags.\n");
1506        warn("    This checkpoint will not restore correctly " \
1507             "and dirty data in the cache will be lost!\n");
1508    }
1509
1510    // Since we don't checkpoint the data in the cache, any dirty data
1511    // will be lost when restoring from a checkpoint of a system that
1512    // wasn't drained properly. Flag the checkpoint as invalid if the
1513    // cache contains dirty data.
1514    bool bad_checkpoint(dirty);
1515    SERIALIZE_SCALAR(bad_checkpoint);
1516}
1517
1518void
1519BaseCache::unserialize(CheckpointIn &cp)
1520{
1521    bool bad_checkpoint;
1522    UNSERIALIZE_SCALAR(bad_checkpoint);
1523    if (bad_checkpoint) {
1524        fatal("Restoring from checkpoints with dirty caches is not "
1525              "supported in the classic memory system. Please remove any "
1526              "caches or drain them properly before taking checkpoints.\n");
1527    }
1528}
1529
1530void
1531BaseCache::regStats()
1532{
1533    MemObject::regStats();
1534
1535    using namespace Stats;
1536
1537    // Hit statistics
1538    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1539        MemCmd cmd(access_idx);
1540        const string &cstr = cmd.toString();
1541
1542        hits[access_idx]
1543            .init(system->maxMasters())
1544            .name(name() + "." + cstr + "_hits")
1545            .desc("number of " + cstr + " hits")
1546            .flags(total | nozero | nonan)
1547            ;
1548        for (int i = 0; i < system->maxMasters(); i++) {
1549            hits[access_idx].subname(i, system->getMasterName(i));
1550        }
1551    }
1552
1553// These macros make it easier to sum the right subset of commands and
1554// to change the subset of commands that are considered "demand" vs
1555// "non-demand"
1556#define SUM_DEMAND(s) \
1557    (s[MemCmd::ReadReq] + s[MemCmd::WriteReq] + s[MemCmd::WriteLineReq] + \
1558     s[MemCmd::ReadExReq] + s[MemCmd::ReadCleanReq] + s[MemCmd::ReadSharedReq])
1559
1560// should writebacks be included here?  prior code was inconsistent...
1561#define SUM_NON_DEMAND(s) \
1562    (s[MemCmd::SoftPFReq] + s[MemCmd::HardPFReq])
1563
1564    demandHits
1565        .name(name() + ".demand_hits")
1566        .desc("number of demand (read+write) hits")
1567        .flags(total | nozero | nonan)
1568        ;
1569    demandHits = SUM_DEMAND(hits);
1570    for (int i = 0; i < system->maxMasters(); i++) {
1571        demandHits.subname(i, system->getMasterName(i));
1572    }
1573
1574    overallHits
1575        .name(name() + ".overall_hits")
1576        .desc("number of overall hits")
1577        .flags(total | nozero | nonan)
1578        ;
1579    overallHits = demandHits + SUM_NON_DEMAND(hits);
1580    for (int i = 0; i < system->maxMasters(); i++) {
1581        overallHits.subname(i, system->getMasterName(i));
1582    }
1583
1584    // Miss statistics
1585    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1586        MemCmd cmd(access_idx);
1587        const string &cstr = cmd.toString();
1588
1589        misses[access_idx]
1590            .init(system->maxMasters())
1591            .name(name() + "." + cstr + "_misses")
1592            .desc("number of " + cstr + " misses")
1593            .flags(total | nozero | nonan)
1594            ;
1595        for (int i = 0; i < system->maxMasters(); i++) {
1596            misses[access_idx].subname(i, system->getMasterName(i));
1597        }
1598    }
1599
1600    demandMisses
1601        .name(name() + ".demand_misses")
1602        .desc("number of demand (read+write) misses")
1603        .flags(total | nozero | nonan)
1604        ;
1605    demandMisses = SUM_DEMAND(misses);
1606    for (int i = 0; i < system->maxMasters(); i++) {
1607        demandMisses.subname(i, system->getMasterName(i));
1608    }
1609
1610    overallMisses
1611        .name(name() + ".overall_misses")
1612        .desc("number of overall misses")
1613        .flags(total | nozero | nonan)
1614        ;
1615    overallMisses = demandMisses + SUM_NON_DEMAND(misses);
1616    for (int i = 0; i < system->maxMasters(); i++) {
1617        overallMisses.subname(i, system->getMasterName(i));
1618    }
1619
1620    // Miss latency statistics
1621    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1622        MemCmd cmd(access_idx);
1623        const string &cstr = cmd.toString();
1624
1625        missLatency[access_idx]
1626            .init(system->maxMasters())
1627            .name(name() + "." + cstr + "_miss_latency")
1628            .desc("number of " + cstr + " miss cycles")
1629            .flags(total | nozero | nonan)
1630            ;
1631        for (int i = 0; i < system->maxMasters(); i++) {
1632            missLatency[access_idx].subname(i, system->getMasterName(i));
1633        }
1634    }
1635
1636    demandMissLatency
1637        .name(name() + ".demand_miss_latency")
1638        .desc("number of demand (read+write) miss cycles")
1639        .flags(total | nozero | nonan)
1640        ;
1641    demandMissLatency = SUM_DEMAND(missLatency);
1642    for (int i = 0; i < system->maxMasters(); i++) {
1643        demandMissLatency.subname(i, system->getMasterName(i));
1644    }
1645
1646    overallMissLatency
1647        .name(name() + ".overall_miss_latency")
1648        .desc("number of overall miss cycles")
1649        .flags(total | nozero | nonan)
1650        ;
1651    overallMissLatency = demandMissLatency + SUM_NON_DEMAND(missLatency);
1652    for (int i = 0; i < system->maxMasters(); i++) {
1653        overallMissLatency.subname(i, system->getMasterName(i));
1654    }
1655
1656    // access formulas
1657    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1658        MemCmd cmd(access_idx);
1659        const string &cstr = cmd.toString();
1660
1661        accesses[access_idx]
1662            .name(name() + "." + cstr + "_accesses")
1663            .desc("number of " + cstr + " accesses(hits+misses)")
1664            .flags(total | nozero | nonan)
1665            ;
1666        accesses[access_idx] = hits[access_idx] + misses[access_idx];
1667
1668        for (int i = 0; i < system->maxMasters(); i++) {
1669            accesses[access_idx].subname(i, system->getMasterName(i));
1670        }
1671    }
1672
1673    demandAccesses
1674        .name(name() + ".demand_accesses")
1675        .desc("number of demand (read+write) accesses")
1676        .flags(total | nozero | nonan)
1677        ;
1678    demandAccesses = demandHits + demandMisses;
1679    for (int i = 0; i < system->maxMasters(); i++) {
1680        demandAccesses.subname(i, system->getMasterName(i));
1681    }
1682
1683    overallAccesses
1684        .name(name() + ".overall_accesses")
1685        .desc("number of overall (read+write) accesses")
1686        .flags(total | nozero | nonan)
1687        ;
1688    overallAccesses = overallHits + overallMisses;
1689    for (int i = 0; i < system->maxMasters(); i++) {
1690        overallAccesses.subname(i, system->getMasterName(i));
1691    }
1692
1693    // miss rate formulas
1694    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1695        MemCmd cmd(access_idx);
1696        const string &cstr = cmd.toString();
1697
1698        missRate[access_idx]
1699            .name(name() + "." + cstr + "_miss_rate")
1700            .desc("miss rate for " + cstr + " accesses")
1701            .flags(total | nozero | nonan)
1702            ;
1703        missRate[access_idx] = misses[access_idx] / accesses[access_idx];
1704
1705        for (int i = 0; i < system->maxMasters(); i++) {
1706            missRate[access_idx].subname(i, system->getMasterName(i));
1707        }
1708    }
1709
1710    demandMissRate
1711        .name(name() + ".demand_miss_rate")
1712        .desc("miss rate for demand accesses")
1713        .flags(total | nozero | nonan)
1714        ;
1715    demandMissRate = demandMisses / demandAccesses;
1716    for (int i = 0; i < system->maxMasters(); i++) {
1717        demandMissRate.subname(i, system->getMasterName(i));
1718    }
1719
1720    overallMissRate
1721        .name(name() + ".overall_miss_rate")
1722        .desc("miss rate for overall accesses")
1723        .flags(total | nozero | nonan)
1724        ;
1725    overallMissRate = overallMisses / overallAccesses;
1726    for (int i = 0; i < system->maxMasters(); i++) {
1727        overallMissRate.subname(i, system->getMasterName(i));
1728    }
1729
1730    // miss latency formulas
1731    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1732        MemCmd cmd(access_idx);
1733        const string &cstr = cmd.toString();
1734
1735        avgMissLatency[access_idx]
1736            .name(name() + "." + cstr + "_avg_miss_latency")
1737            .desc("average " + cstr + " miss latency")
1738            .flags(total | nozero | nonan)
1739            ;
1740        avgMissLatency[access_idx] =
1741            missLatency[access_idx] / misses[access_idx];
1742
1743        for (int i = 0; i < system->maxMasters(); i++) {
1744            avgMissLatency[access_idx].subname(i, system->getMasterName(i));
1745        }
1746    }
1747
1748    demandAvgMissLatency
1749        .name(name() + ".demand_avg_miss_latency")
1750        .desc("average overall miss latency")
1751        .flags(total | nozero | nonan)
1752        ;
1753    demandAvgMissLatency = demandMissLatency / demandMisses;
1754    for (int i = 0; i < system->maxMasters(); i++) {
1755        demandAvgMissLatency.subname(i, system->getMasterName(i));
1756    }
1757
1758    overallAvgMissLatency
1759        .name(name() + ".overall_avg_miss_latency")
1760        .desc("average overall miss latency")
1761        .flags(total | nozero | nonan)
1762        ;
1763    overallAvgMissLatency = overallMissLatency / overallMisses;
1764    for (int i = 0; i < system->maxMasters(); i++) {
1765        overallAvgMissLatency.subname(i, system->getMasterName(i));
1766    }
1767
1768    blocked_cycles.init(NUM_BLOCKED_CAUSES);
1769    blocked_cycles
1770        .name(name() + ".blocked_cycles")
1771        .desc("number of cycles access was blocked")
1772        .subname(Blocked_NoMSHRs, "no_mshrs")
1773        .subname(Blocked_NoTargets, "no_targets")
1774        ;
1775
1776
1777    blocked_causes.init(NUM_BLOCKED_CAUSES);
1778    blocked_causes
1779        .name(name() + ".blocked")
1780        .desc("number of cycles access was blocked")
1781        .subname(Blocked_NoMSHRs, "no_mshrs")
1782        .subname(Blocked_NoTargets, "no_targets")
1783        ;
1784
1785    avg_blocked
1786        .name(name() + ".avg_blocked_cycles")
1787        .desc("average number of cycles each access was blocked")
1788        .subname(Blocked_NoMSHRs, "no_mshrs")
1789        .subname(Blocked_NoTargets, "no_targets")
1790        ;
1791
1792    avg_blocked = blocked_cycles / blocked_causes;
1793
1794    unusedPrefetches
1795        .name(name() + ".unused_prefetches")
1796        .desc("number of HardPF blocks evicted w/o reference")
1797        .flags(nozero)
1798        ;
1799
1800    writebacks
1801        .init(system->maxMasters())
1802        .name(name() + ".writebacks")
1803        .desc("number of writebacks")
1804        .flags(total | nozero | nonan)
1805        ;
1806    for (int i = 0; i < system->maxMasters(); i++) {
1807        writebacks.subname(i, system->getMasterName(i));
1808    }
1809
1810    // MSHR statistics
1811    // MSHR hit statistics
1812    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1813        MemCmd cmd(access_idx);
1814        const string &cstr = cmd.toString();
1815
1816        mshr_hits[access_idx]
1817            .init(system->maxMasters())
1818            .name(name() + "." + cstr + "_mshr_hits")
1819            .desc("number of " + cstr + " MSHR hits")
1820            .flags(total | nozero | nonan)
1821            ;
1822        for (int i = 0; i < system->maxMasters(); i++) {
1823            mshr_hits[access_idx].subname(i, system->getMasterName(i));
1824        }
1825    }
1826
1827    demandMshrHits
1828        .name(name() + ".demand_mshr_hits")
1829        .desc("number of demand (read+write) MSHR hits")
1830        .flags(total | nozero | nonan)
1831        ;
1832    demandMshrHits = SUM_DEMAND(mshr_hits);
1833    for (int i = 0; i < system->maxMasters(); i++) {
1834        demandMshrHits.subname(i, system->getMasterName(i));
1835    }
1836
1837    overallMshrHits
1838        .name(name() + ".overall_mshr_hits")
1839        .desc("number of overall MSHR hits")
1840        .flags(total | nozero | nonan)
1841        ;
1842    overallMshrHits = demandMshrHits + SUM_NON_DEMAND(mshr_hits);
1843    for (int i = 0; i < system->maxMasters(); i++) {
1844        overallMshrHits.subname(i, system->getMasterName(i));
1845    }
1846
1847    // MSHR miss statistics
1848    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1849        MemCmd cmd(access_idx);
1850        const string &cstr = cmd.toString();
1851
1852        mshr_misses[access_idx]
1853            .init(system->maxMasters())
1854            .name(name() + "." + cstr + "_mshr_misses")
1855            .desc("number of " + cstr + " MSHR misses")
1856            .flags(total | nozero | nonan)
1857            ;
1858        for (int i = 0; i < system->maxMasters(); i++) {
1859            mshr_misses[access_idx].subname(i, system->getMasterName(i));
1860        }
1861    }
1862
1863    demandMshrMisses
1864        .name(name() + ".demand_mshr_misses")
1865        .desc("number of demand (read+write) MSHR misses")
1866        .flags(total | nozero | nonan)
1867        ;
1868    demandMshrMisses = SUM_DEMAND(mshr_misses);
1869    for (int i = 0; i < system->maxMasters(); i++) {
1870        demandMshrMisses.subname(i, system->getMasterName(i));
1871    }
1872
1873    overallMshrMisses
1874        .name(name() + ".overall_mshr_misses")
1875        .desc("number of overall MSHR misses")
1876        .flags(total | nozero | nonan)
1877        ;
1878    overallMshrMisses = demandMshrMisses + SUM_NON_DEMAND(mshr_misses);
1879    for (int i = 0; i < system->maxMasters(); i++) {
1880        overallMshrMisses.subname(i, system->getMasterName(i));
1881    }
1882
1883    // MSHR miss latency statistics
1884    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1885        MemCmd cmd(access_idx);
1886        const string &cstr = cmd.toString();
1887
1888        mshr_miss_latency[access_idx]
1889            .init(system->maxMasters())
1890            .name(name() + "." + cstr + "_mshr_miss_latency")
1891            .desc("number of " + cstr + " MSHR miss cycles")
1892            .flags(total | nozero | nonan)
1893            ;
1894        for (int i = 0; i < system->maxMasters(); i++) {
1895            mshr_miss_latency[access_idx].subname(i, system->getMasterName(i));
1896        }
1897    }
1898
1899    demandMshrMissLatency
1900        .name(name() + ".demand_mshr_miss_latency")
1901        .desc("number of demand (read+write) MSHR miss cycles")
1902        .flags(total | nozero | nonan)
1903        ;
1904    demandMshrMissLatency = SUM_DEMAND(mshr_miss_latency);
1905    for (int i = 0; i < system->maxMasters(); i++) {
1906        demandMshrMissLatency.subname(i, system->getMasterName(i));
1907    }
1908
1909    overallMshrMissLatency
1910        .name(name() + ".overall_mshr_miss_latency")
1911        .desc("number of overall MSHR miss cycles")
1912        .flags(total | nozero | nonan)
1913        ;
1914    overallMshrMissLatency =
1915        demandMshrMissLatency + SUM_NON_DEMAND(mshr_miss_latency);
1916    for (int i = 0; i < system->maxMasters(); i++) {
1917        overallMshrMissLatency.subname(i, system->getMasterName(i));
1918    }
1919
1920    // MSHR uncacheable statistics
1921    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1922        MemCmd cmd(access_idx);
1923        const string &cstr = cmd.toString();
1924
1925        mshr_uncacheable[access_idx]
1926            .init(system->maxMasters())
1927            .name(name() + "." + cstr + "_mshr_uncacheable")
1928            .desc("number of " + cstr + " MSHR uncacheable")
1929            .flags(total | nozero | nonan)
1930            ;
1931        for (int i = 0; i < system->maxMasters(); i++) {
1932            mshr_uncacheable[access_idx].subname(i, system->getMasterName(i));
1933        }
1934    }
1935
1936    overallMshrUncacheable
1937        .name(name() + ".overall_mshr_uncacheable_misses")
1938        .desc("number of overall MSHR uncacheable misses")
1939        .flags(total | nozero | nonan)
1940        ;
1941    overallMshrUncacheable =
1942        SUM_DEMAND(mshr_uncacheable) + SUM_NON_DEMAND(mshr_uncacheable);
1943    for (int i = 0; i < system->maxMasters(); i++) {
1944        overallMshrUncacheable.subname(i, system->getMasterName(i));
1945    }
1946
1947    // MSHR miss latency statistics
1948    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1949        MemCmd cmd(access_idx);
1950        const string &cstr = cmd.toString();
1951
1952        mshr_uncacheable_lat[access_idx]
1953            .init(system->maxMasters())
1954            .name(name() + "." + cstr + "_mshr_uncacheable_latency")
1955            .desc("number of " + cstr + " MSHR uncacheable cycles")
1956            .flags(total | nozero | nonan)
1957            ;
1958        for (int i = 0; i < system->maxMasters(); i++) {
1959            mshr_uncacheable_lat[access_idx].subname(
1960                i, system->getMasterName(i));
1961        }
1962    }
1963
1964    overallMshrUncacheableLatency
1965        .name(name() + ".overall_mshr_uncacheable_latency")
1966        .desc("number of overall MSHR uncacheable cycles")
1967        .flags(total | nozero | nonan)
1968        ;
1969    overallMshrUncacheableLatency =
1970        SUM_DEMAND(mshr_uncacheable_lat) +
1971        SUM_NON_DEMAND(mshr_uncacheable_lat);
1972    for (int i = 0; i < system->maxMasters(); i++) {
1973        overallMshrUncacheableLatency.subname(i, system->getMasterName(i));
1974    }
1975
1976#if 0
1977    // MSHR access formulas
1978    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1979        MemCmd cmd(access_idx);
1980        const string &cstr = cmd.toString();
1981
1982        mshrAccesses[access_idx]
1983            .name(name() + "." + cstr + "_mshr_accesses")
1984            .desc("number of " + cstr + " mshr accesses(hits+misses)")
1985            .flags(total | nozero | nonan)
1986            ;
1987        mshrAccesses[access_idx] =
1988            mshr_hits[access_idx] + mshr_misses[access_idx]
1989            + mshr_uncacheable[access_idx];
1990    }
1991
1992    demandMshrAccesses
1993        .name(name() + ".demand_mshr_accesses")
1994        .desc("number of demand (read+write) mshr accesses")
1995        .flags(total | nozero | nonan)
1996        ;
1997    demandMshrAccesses = demandMshrHits + demandMshrMisses;
1998
1999    overallMshrAccesses
2000        .name(name() + ".overall_mshr_accesses")
2001        .desc("number of overall (read+write) mshr accesses")
2002        .flags(total | nozero | nonan)
2003        ;
2004    overallMshrAccesses = overallMshrHits + overallMshrMisses
2005        + overallMshrUncacheable;
2006#endif
2007
2008    // MSHR miss rate formulas
2009    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2010        MemCmd cmd(access_idx);
2011        const string &cstr = cmd.toString();
2012
2013        mshrMissRate[access_idx]
2014            .name(name() + "." + cstr + "_mshr_miss_rate")
2015            .desc("mshr miss rate for " + cstr + " accesses")
2016            .flags(total | nozero | nonan)
2017            ;
2018        mshrMissRate[access_idx] =
2019            mshr_misses[access_idx] / accesses[access_idx];
2020
2021        for (int i = 0; i < system->maxMasters(); i++) {
2022            mshrMissRate[access_idx].subname(i, system->getMasterName(i));
2023        }
2024    }
2025
2026    demandMshrMissRate
2027        .name(name() + ".demand_mshr_miss_rate")
2028        .desc("mshr miss rate for demand accesses")
2029        .flags(total | nozero | nonan)
2030        ;
2031    demandMshrMissRate = demandMshrMisses / demandAccesses;
2032    for (int i = 0; i < system->maxMasters(); i++) {
2033        demandMshrMissRate.subname(i, system->getMasterName(i));
2034    }
2035
2036    overallMshrMissRate
2037        .name(name() + ".overall_mshr_miss_rate")
2038        .desc("mshr miss rate for overall accesses")
2039        .flags(total | nozero | nonan)
2040        ;
2041    overallMshrMissRate = overallMshrMisses / overallAccesses;
2042    for (int i = 0; i < system->maxMasters(); i++) {
2043        overallMshrMissRate.subname(i, system->getMasterName(i));
2044    }
2045
2046    // mshrMiss latency formulas
2047    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2048        MemCmd cmd(access_idx);
2049        const string &cstr = cmd.toString();
2050
2051        avgMshrMissLatency[access_idx]
2052            .name(name() + "." + cstr + "_avg_mshr_miss_latency")
2053            .desc("average " + cstr + " mshr miss latency")
2054            .flags(total | nozero | nonan)
2055            ;
2056        avgMshrMissLatency[access_idx] =
2057            mshr_miss_latency[access_idx] / mshr_misses[access_idx];
2058
2059        for (int i = 0; i < system->maxMasters(); i++) {
2060            avgMshrMissLatency[access_idx].subname(
2061                i, system->getMasterName(i));
2062        }
2063    }
2064
2065    demandAvgMshrMissLatency
2066        .name(name() + ".demand_avg_mshr_miss_latency")
2067        .desc("average overall mshr miss latency")
2068        .flags(total | nozero | nonan)
2069        ;
2070    demandAvgMshrMissLatency = demandMshrMissLatency / demandMshrMisses;
2071    for (int i = 0; i < system->maxMasters(); i++) {
2072        demandAvgMshrMissLatency.subname(i, system->getMasterName(i));
2073    }
2074
2075    overallAvgMshrMissLatency
2076        .name(name() + ".overall_avg_mshr_miss_latency")
2077        .desc("average overall mshr miss latency")
2078        .flags(total | nozero | nonan)
2079        ;
2080    overallAvgMshrMissLatency = overallMshrMissLatency / overallMshrMisses;
2081    for (int i = 0; i < system->maxMasters(); i++) {
2082        overallAvgMshrMissLatency.subname(i, system->getMasterName(i));
2083    }
2084
2085    // mshrUncacheable latency formulas
2086    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2087        MemCmd cmd(access_idx);
2088        const string &cstr = cmd.toString();
2089
2090        avgMshrUncacheableLatency[access_idx]
2091            .name(name() + "." + cstr + "_avg_mshr_uncacheable_latency")
2092            .desc("average " + cstr + " mshr uncacheable latency")
2093            .flags(total | nozero | nonan)
2094            ;
2095        avgMshrUncacheableLatency[access_idx] =
2096            mshr_uncacheable_lat[access_idx] / mshr_uncacheable[access_idx];
2097
2098        for (int i = 0; i < system->maxMasters(); i++) {
2099            avgMshrUncacheableLatency[access_idx].subname(
2100                i, system->getMasterName(i));
2101        }
2102    }
2103
2104    overallAvgMshrUncacheableLatency
2105        .name(name() + ".overall_avg_mshr_uncacheable_latency")
2106        .desc("average overall mshr uncacheable latency")
2107        .flags(total | nozero | nonan)
2108        ;
2109    overallAvgMshrUncacheableLatency =
2110        overallMshrUncacheableLatency / overallMshrUncacheable;
2111    for (int i = 0; i < system->maxMasters(); i++) {
2112        overallAvgMshrUncacheableLatency.subname(i, system->getMasterName(i));
2113    }
2114
2115    replacements
2116        .name(name() + ".replacements")
2117        .desc("number of replacements")
2118        ;
2119}
2120
2121///////////////
2122//
2123// CpuSidePort
2124//
2125///////////////
2126bool
2127BaseCache::CpuSidePort::recvTimingSnoopResp(PacketPtr pkt)
2128{
2129    // Snoops shouldn't happen when bypassing caches
2130    assert(!cache->system->bypassCaches());
2131
2132    assert(pkt->isResponse());
2133
2134    // Express snoop responses from master to slave, e.g., from L1 to L2
2135    cache->recvTimingSnoopResp(pkt);
2136    return true;
2137}
2138
2139
2140bool
2141BaseCache::CpuSidePort::tryTiming(PacketPtr pkt)
2142{
2143    if (cache->system->bypassCaches() || pkt->isExpressSnoop()) {
2144        // always let express snoop packets through even if blocked
2145        return true;
2146    } else if (blocked || mustSendRetry) {
2147        // either already committed to send a retry, or blocked
2148        mustSendRetry = true;
2149        return false;
2150    }
2151    mustSendRetry = false;
2152    return true;
2153}
2154
2155bool
2156BaseCache::CpuSidePort::recvTimingReq(PacketPtr pkt)
2157{
2158    assert(pkt->isRequest());
2159
2160    if (cache->system->bypassCaches()) {
2161        // Just forward the packet if caches are disabled.
2162        // @todo This should really enqueue the packet rather
2163        bool M5_VAR_USED success = cache->memSidePort.sendTimingReq(pkt);
2164        assert(success);
2165        return true;
2166    } else if (tryTiming(pkt)) {
2167        cache->recvTimingReq(pkt);
2168        return true;
2169    }
2170    return false;
2171}
2172
2173Tick
2174BaseCache::CpuSidePort::recvAtomic(PacketPtr pkt)
2175{
2176    if (cache->system->bypassCaches()) {
2177        // Forward the request if the system is in cache bypass mode.
2178        return cache->memSidePort.sendAtomic(pkt);
2179    } else {
2180        return cache->recvAtomic(pkt);
2181    }
2182}
2183
2184void
2185BaseCache::CpuSidePort::recvFunctional(PacketPtr pkt)
2186{
2187    if (cache->system->bypassCaches()) {
2188        // The cache should be flushed if we are in cache bypass mode,
2189        // so we don't need to check if we need to update anything.
2190        cache->memSidePort.sendFunctional(pkt);
2191        return;
2192    }
2193
2194    // functional request
2195    cache->functionalAccess(pkt, true);
2196}
2197
2198AddrRangeList
2199BaseCache::CpuSidePort::getAddrRanges() const
2200{
2201    return cache->getAddrRanges();
2202}
2203
2204
2205BaseCache::
2206CpuSidePort::CpuSidePort(const std::string &_name, BaseCache *_cache,
2207                         const std::string &_label)
2208    : CacheSlavePort(_name, _cache, _label), cache(_cache)
2209{
2210}
2211
2212///////////////
2213//
2214// MemSidePort
2215//
2216///////////////
2217bool
2218BaseCache::MemSidePort::recvTimingResp(PacketPtr pkt)
2219{
2220    cache->recvTimingResp(pkt);
2221    return true;
2222}
2223
2224// Express snooping requests to memside port
2225void
2226BaseCache::MemSidePort::recvTimingSnoopReq(PacketPtr pkt)
2227{
2228    // Snoops shouldn't happen when bypassing caches
2229    assert(!cache->system->bypassCaches());
2230
2231    // handle snooping requests
2232    cache->recvTimingSnoopReq(pkt);
2233}
2234
2235Tick
2236BaseCache::MemSidePort::recvAtomicSnoop(PacketPtr pkt)
2237{
2238    // Snoops shouldn't happen when bypassing caches
2239    assert(!cache->system->bypassCaches());
2240
2241    return cache->recvAtomicSnoop(pkt);
2242}
2243
2244void
2245BaseCache::MemSidePort::recvFunctionalSnoop(PacketPtr pkt)
2246{
2247    // Snoops shouldn't happen when bypassing caches
2248    assert(!cache->system->bypassCaches());
2249
2250    // functional snoop (note that in contrast to atomic we don't have
2251    // a specific functionalSnoop method, as they have the same
2252    // behaviour regardless)
2253    cache->functionalAccess(pkt, false);
2254}
2255
2256void
2257BaseCache::CacheReqPacketQueue::sendDeferredPacket()
2258{
2259    // sanity check
2260    assert(!waitingOnRetry);
2261
2262    // there should never be any deferred request packets in the
2263    // queue, instead we resly on the cache to provide the packets
2264    // from the MSHR queue or write queue
2265    assert(deferredPacketReadyTime() == MaxTick);
2266
2267    // check for request packets (requests & writebacks)
2268    QueueEntry* entry = cache.getNextQueueEntry();
2269
2270    if (!entry) {
2271        // can happen if e.g. we attempt a writeback and fail, but
2272        // before the retry, the writeback is eliminated because
2273        // we snoop another cache's ReadEx.
2274    } else {
2275        // let our snoop responses go first if there are responses to
2276        // the same addresses
2277        if (checkConflictingSnoop(entry->blkAddr)) {
2278            return;
2279        }
2280        waitingOnRetry = entry->sendPacket(cache);
2281    }
2282
2283    // if we succeeded and are not waiting for a retry, schedule the
2284    // next send considering when the next queue is ready, note that
2285    // snoop responses have their own packet queue and thus schedule
2286    // their own events
2287    if (!waitingOnRetry) {
2288        schedSendEvent(cache.nextQueueReadyTime());
2289    }
2290}
2291
2292BaseCache::MemSidePort::MemSidePort(const std::string &_name,
2293                                    BaseCache *_cache,
2294                                    const std::string &_label)
2295    : CacheMasterPort(_name, _cache, _reqQueue, _snoopRespQueue),
2296      _reqQueue(*_cache, *this, _snoopRespQueue, _label),
2297      _snoopRespQueue(*_cache, *this, _label), cache(_cache)
2298{
2299}
2300