base.cc revision 12749
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 TempCacheBlk();
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
167Addr
168BaseCache::regenerateBlkAddr(CacheBlk* blk)
169{
170    if (blk != tempBlock) {
171        return tags->regenerateBlkAddr(blk);
172    } else {
173        return tempBlock->getAddr();
174    }
175}
176
177void
178BaseCache::init()
179{
180    if (!cpuSidePort.isConnected() || !memSidePort.isConnected())
181        fatal("Cache ports on %s are not connected\n", name());
182    cpuSidePort.sendRangeChange();
183    forwardSnoops = cpuSidePort.isSnooping();
184}
185
186BaseMasterPort &
187BaseCache::getMasterPort(const std::string &if_name, PortID idx)
188{
189    if (if_name == "mem_side") {
190        return memSidePort;
191    }  else {
192        return MemObject::getMasterPort(if_name, idx);
193    }
194}
195
196BaseSlavePort &
197BaseCache::getSlavePort(const std::string &if_name, PortID idx)
198{
199    if (if_name == "cpu_side") {
200        return cpuSidePort;
201    } else {
202        return MemObject::getSlavePort(if_name, idx);
203    }
204}
205
206bool
207BaseCache::inRange(Addr addr) const
208{
209    for (const auto& r : addrRanges) {
210        if (r.contains(addr)) {
211            return true;
212       }
213    }
214    return false;
215}
216
217void
218BaseCache::handleTimingReqHit(PacketPtr pkt, CacheBlk *blk, Tick request_time)
219{
220    if (pkt->needsResponse()) {
221        pkt->makeTimingResponse();
222        // @todo: Make someone pay for this
223        pkt->headerDelay = pkt->payloadDelay = 0;
224
225        // In this case we are considering request_time that takes
226        // into account the delay of the xbar, if any, and just
227        // lat, neglecting responseLatency, modelling hit latency
228        // just as lookupLatency or or the value of lat overriden
229        // by access(), that calls accessBlock() function.
230        cpuSidePort.schedTimingResp(pkt, request_time, true);
231    } else {
232        DPRINTF(Cache, "%s satisfied %s, no response needed\n", __func__,
233                pkt->print());
234
235        // queue the packet for deletion, as the sending cache is
236        // still relying on it; if the block is found in access(),
237        // CleanEvict and Writeback messages will be deleted
238        // here as well
239        pendingDelete.reset(pkt);
240    }
241}
242
243void
244BaseCache::handleTimingReqMiss(PacketPtr pkt, MSHR *mshr, CacheBlk *blk,
245                               Tick forward_time, Tick request_time)
246{
247    if (mshr) {
248        /// MSHR hit
249        /// @note writebacks will be checked in getNextMSHR()
250        /// for any conflicting requests to the same block
251
252        //@todo remove hw_pf here
253
254        // Coalesce unless it was a software prefetch (see above).
255        if (pkt) {
256            assert(!pkt->isWriteback());
257            // CleanEvicts corresponding to blocks which have
258            // outstanding requests in MSHRs are simply sunk here
259            if (pkt->cmd == MemCmd::CleanEvict) {
260                pendingDelete.reset(pkt);
261            } else if (pkt->cmd == MemCmd::WriteClean) {
262                // A WriteClean should never coalesce with any
263                // outstanding cache maintenance requests.
264
265                // We use forward_time here because there is an
266                // uncached memory write, forwarded to WriteBuffer.
267                allocateWriteBuffer(pkt, forward_time);
268            } else {
269                DPRINTF(Cache, "%s coalescing MSHR for %s\n", __func__,
270                        pkt->print());
271
272                assert(pkt->req->masterId() < system->maxMasters());
273                mshr_hits[pkt->cmdToIndex()][pkt->req->masterId()]++;
274
275                // We use forward_time here because it is the same
276                // considering new targets. We have multiple
277                // requests for the same address here. It
278                // specifies the latency to allocate an internal
279                // buffer and to schedule an event to the queued
280                // port and also takes into account the additional
281                // delay of the xbar.
282                mshr->allocateTarget(pkt, forward_time, order++,
283                                     allocOnFill(pkt->cmd));
284                if (mshr->getNumTargets() == numTarget) {
285                    noTargetMSHR = mshr;
286                    setBlocked(Blocked_NoTargets);
287                    // need to be careful with this... if this mshr isn't
288                    // ready yet (i.e. time > curTick()), we don't want to
289                    // move it ahead of mshrs that are ready
290                    // mshrQueue.moveToFront(mshr);
291                }
292            }
293        }
294    } else {
295        // no MSHR
296        assert(pkt->req->masterId() < system->maxMasters());
297        mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
298
299        if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean) {
300            // We use forward_time here because there is an
301            // writeback or writeclean, forwarded to WriteBuffer.
302            allocateWriteBuffer(pkt, forward_time);
303        } else {
304            if (blk && blk->isValid()) {
305                // If we have a write miss to a valid block, we
306                // need to mark the block non-readable.  Otherwise
307                // if we allow reads while there's an outstanding
308                // write miss, the read could return stale data
309                // out of the cache block... a more aggressive
310                // system could detect the overlap (if any) and
311                // forward data out of the MSHRs, but we don't do
312                // that yet.  Note that we do need to leave the
313                // block valid so that it stays in the cache, in
314                // case we get an upgrade response (and hence no
315                // new data) when the write miss completes.
316                // As long as CPUs do proper store/load forwarding
317                // internally, and have a sufficiently weak memory
318                // model, this is probably unnecessary, but at some
319                // point it must have seemed like we needed it...
320                assert((pkt->needsWritable() && !blk->isWritable()) ||
321                       pkt->req->isCacheMaintenance());
322                blk->status &= ~BlkReadable;
323            }
324            // Here we are using forward_time, modelling the latency of
325            // a miss (outbound) just as forwardLatency, neglecting the
326            // lookupLatency component.
327            allocateMissBuffer(pkt, forward_time);
328        }
329    }
330}
331
332void
333BaseCache::recvTimingReq(PacketPtr pkt)
334{
335    // anything that is merely forwarded pays for the forward latency and
336    // the delay provided by the crossbar
337    Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
338
339    // We use lookupLatency here because it is used to specify the latency
340    // to access.
341    Cycles lat = lookupLatency;
342    CacheBlk *blk = nullptr;
343    bool satisfied = false;
344    {
345        PacketList writebacks;
346        // Note that lat is passed by reference here. The function
347        // access() calls accessBlock() which can modify lat value.
348        satisfied = access(pkt, blk, lat, writebacks);
349
350        // copy writebacks to write buffer here to ensure they logically
351        // proceed anything happening below
352        doWritebacks(writebacks, forward_time);
353    }
354
355    // Here we charge the headerDelay that takes into account the latencies
356    // of the bus, if the packet comes from it.
357    // The latency charged it is just lat that is the value of lookupLatency
358    // modified by access() function, or if not just lookupLatency.
359    // In case of a hit we are neglecting response latency.
360    // In case of a miss we are neglecting forward latency.
361    Tick request_time = clockEdge(lat) + pkt->headerDelay;
362    // Here we reset the timing of the packet.
363    pkt->headerDelay = pkt->payloadDelay = 0;
364    // track time of availability of next prefetch, if any
365    Tick next_pf_time = MaxTick;
366
367    if (satisfied) {
368        // if need to notify the prefetcher we have to do it before
369        // anything else as later handleTimingReqHit might turn the
370        // packet in a response
371        if (prefetcher &&
372            (prefetchOnAccess || (blk && blk->wasPrefetched()))) {
373            if (blk)
374                blk->status &= ~BlkHWPrefetched;
375
376            // Don't notify on SWPrefetch
377            if (!pkt->cmd.isSWPrefetch()) {
378                assert(!pkt->req->isCacheMaintenance());
379                next_pf_time = prefetcher->notify(pkt);
380            }
381        }
382
383        handleTimingReqHit(pkt, blk, request_time);
384    } else {
385        handleTimingReqMiss(pkt, blk, forward_time, request_time);
386
387        // We should call the prefetcher reguardless if the request is
388        // satisfied or not, reguardless if the request is in the MSHR
389        // or not. The request could be a ReadReq hit, but still not
390        // satisfied (potentially because of a prior write to the same
391        // cache line. So, even when not satisfied, there is an MSHR
392        // already allocated for this, we need to let the prefetcher
393        // know about the request
394
395        // Don't notify prefetcher on SWPrefetch or cache maintenance
396        // operations
397        if (prefetcher && pkt &&
398            !pkt->cmd.isSWPrefetch() &&
399            !pkt->req->isCacheMaintenance()) {
400            next_pf_time = prefetcher->notify(pkt);
401        }
402    }
403
404    if (next_pf_time != MaxTick) {
405        schedMemSideSendEvent(next_pf_time);
406    }
407}
408
409void
410BaseCache::handleUncacheableWriteResp(PacketPtr pkt)
411{
412    Tick completion_time = clockEdge(responseLatency) +
413        pkt->headerDelay + pkt->payloadDelay;
414
415    // Reset the bus additional time as it is now accounted for
416    pkt->headerDelay = pkt->payloadDelay = 0;
417
418    cpuSidePort.schedTimingResp(pkt, completion_time, true);
419}
420
421void
422BaseCache::recvTimingResp(PacketPtr pkt)
423{
424    assert(pkt->isResponse());
425
426    // all header delay should be paid for by the crossbar, unless
427    // this is a prefetch response from above
428    panic_if(pkt->headerDelay != 0 && pkt->cmd != MemCmd::HardPFResp,
429             "%s saw a non-zero packet delay\n", name());
430
431    const bool is_error = pkt->isError();
432
433    if (is_error) {
434        DPRINTF(Cache, "%s: Cache received %s with error\n", __func__,
435                pkt->print());
436    }
437
438    DPRINTF(Cache, "%s: Handling response %s\n", __func__,
439            pkt->print());
440
441    // if this is a write, we should be looking at an uncacheable
442    // write
443    if (pkt->isWrite()) {
444        assert(pkt->req->isUncacheable());
445        handleUncacheableWriteResp(pkt);
446        return;
447    }
448
449    // we have dealt with any (uncacheable) writes above, from here on
450    // we know we are dealing with an MSHR due to a miss or a prefetch
451    MSHR *mshr = dynamic_cast<MSHR*>(pkt->popSenderState());
452    assert(mshr);
453
454    if (mshr == noTargetMSHR) {
455        // we always clear at least one target
456        clearBlocked(Blocked_NoTargets);
457        noTargetMSHR = nullptr;
458    }
459
460    // Initial target is used just for stats
461    MSHR::Target *initial_tgt = mshr->getTarget();
462    int stats_cmd_idx = initial_tgt->pkt->cmdToIndex();
463    Tick miss_latency = curTick() - initial_tgt->recvTime;
464
465    if (pkt->req->isUncacheable()) {
466        assert(pkt->req->masterId() < system->maxMasters());
467        mshr_uncacheable_lat[stats_cmd_idx][pkt->req->masterId()] +=
468            miss_latency;
469    } else {
470        assert(pkt->req->masterId() < system->maxMasters());
471        mshr_miss_latency[stats_cmd_idx][pkt->req->masterId()] +=
472            miss_latency;
473    }
474
475    PacketList writebacks;
476
477    bool is_fill = !mshr->isForward &&
478        (pkt->isRead() || pkt->cmd == MemCmd::UpgradeResp);
479
480    CacheBlk *blk = tags->findBlock(pkt->getAddr(), pkt->isSecure());
481
482    if (is_fill && !is_error) {
483        DPRINTF(Cache, "Block for addr %#llx being updated in Cache\n",
484                pkt->getAddr());
485
486        blk = handleFill(pkt, blk, writebacks, mshr->allocOnFill());
487        assert(blk != nullptr);
488    }
489
490    if (blk && blk->isValid() && pkt->isClean() && !pkt->isInvalidate()) {
491        // The block was marked not readable while there was a pending
492        // cache maintenance operation, restore its flag.
493        blk->status |= BlkReadable;
494    }
495
496    if (blk && blk->isWritable() && !pkt->req->isCacheInvalidate()) {
497        // If at this point the referenced block is writable and the
498        // response is not a cache invalidate, we promote targets that
499        // were deferred as we couldn't guarrantee a writable copy
500        mshr->promoteWritable();
501    }
502
503    serviceMSHRTargets(mshr, pkt, blk, writebacks);
504
505    if (mshr->promoteDeferredTargets()) {
506        // avoid later read getting stale data while write miss is
507        // outstanding.. see comment in timingAccess()
508        if (blk) {
509            blk->status &= ~BlkReadable;
510        }
511        mshrQueue.markPending(mshr);
512        schedMemSideSendEvent(clockEdge() + pkt->payloadDelay);
513    } else {
514        // while we deallocate an mshr from the queue we still have to
515        // check the isFull condition before and after as we might
516        // have been using the reserved entries already
517        const bool was_full = mshrQueue.isFull();
518        mshrQueue.deallocate(mshr);
519        if (was_full && !mshrQueue.isFull()) {
520            clearBlocked(Blocked_NoMSHRs);
521        }
522
523        // Request the bus for a prefetch if this deallocation freed enough
524        // MSHRs for a prefetch to take place
525        if (prefetcher && mshrQueue.canPrefetch()) {
526            Tick next_pf_time = std::max(prefetcher->nextPrefetchReadyTime(),
527                                         clockEdge());
528            if (next_pf_time != MaxTick)
529                schedMemSideSendEvent(next_pf_time);
530        }
531    }
532
533    // if we used temp block, check to see if its valid and then clear it out
534    if (blk == tempBlock && tempBlock->isValid()) {
535        evictBlock(blk, writebacks);
536    }
537
538    const Tick forward_time = clockEdge(forwardLatency) + pkt->headerDelay;
539    // copy writebacks to write buffer
540    doWritebacks(writebacks, forward_time);
541
542    DPRINTF(CacheVerbose, "%s: Leaving with %s\n", __func__, pkt->print());
543    delete pkt;
544}
545
546
547Tick
548BaseCache::recvAtomic(PacketPtr pkt)
549{
550    // We are in atomic mode so we pay just for lookupLatency here.
551    Cycles lat = lookupLatency;
552
553    // follow the same flow as in recvTimingReq, and check if a cache
554    // above us is responding
555    if (pkt->cacheResponding() && !pkt->isClean()) {
556        assert(!pkt->req->isCacheInvalidate());
557        DPRINTF(Cache, "Cache above responding to %s: not responding\n",
558                pkt->print());
559
560        // if a cache is responding, and it had the line in Owned
561        // rather than Modified state, we need to invalidate any
562        // copies that are not on the same path to memory
563        assert(pkt->needsWritable() && !pkt->responderHadWritable());
564        lat += ticksToCycles(memSidePort.sendAtomic(pkt));
565
566        return lat * clockPeriod();
567    }
568
569    // should assert here that there are no outstanding MSHRs or
570    // writebacks... that would mean that someone used an atomic
571    // access in timing mode
572
573    CacheBlk *blk = nullptr;
574    PacketList writebacks;
575    bool satisfied = access(pkt, blk, lat, writebacks);
576
577    if (pkt->isClean() && blk && blk->isDirty()) {
578        // A cache clean opearation is looking for a dirty
579        // block. If a dirty block is encountered a WriteClean
580        // will update any copies to the path to the memory
581        // until the point of reference.
582        DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
583                __func__, pkt->print(), blk->print());
584        PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(), pkt->id);
585        writebacks.push_back(wb_pkt);
586        pkt->setSatisfied();
587    }
588
589    // handle writebacks resulting from the access here to ensure they
590    // logically proceed anything happening below
591    doWritebacksAtomic(writebacks);
592    assert(writebacks.empty());
593
594    if (!satisfied) {
595        lat += handleAtomicReqMiss(pkt, blk, writebacks);
596    }
597
598    // Note that we don't invoke the prefetcher at all in atomic mode.
599    // It's not clear how to do it properly, particularly for
600    // prefetchers that aggressively generate prefetch candidates and
601    // rely on bandwidth contention to throttle them; these will tend
602    // to pollute the cache in atomic mode since there is no bandwidth
603    // contention.  If we ever do want to enable prefetching in atomic
604    // mode, though, this is the place to do it... see timingAccess()
605    // for an example (though we'd want to issue the prefetch(es)
606    // immediately rather than calling requestMemSideBus() as we do
607    // there).
608
609    // do any writebacks resulting from the response handling
610    doWritebacksAtomic(writebacks);
611
612    // if we used temp block, check to see if its valid and if so
613    // clear it out, but only do so after the call to recvAtomic is
614    // finished so that any downstream observers (such as a snoop
615    // filter), first see the fill, and only then see the eviction
616    if (blk == tempBlock && tempBlock->isValid()) {
617        // the atomic CPU calls recvAtomic for fetch and load/store
618        // sequentuially, and we may already have a tempBlock
619        // writeback from the fetch that we have not yet sent
620        if (tempBlockWriteback) {
621            // if that is the case, write the prevoius one back, and
622            // do not schedule any new event
623            writebackTempBlockAtomic();
624        } else {
625            // the writeback/clean eviction happens after the call to
626            // recvAtomic has finished (but before any successive
627            // calls), so that the response handling from the fill is
628            // allowed to happen first
629            schedule(writebackTempBlockAtomicEvent, curTick());
630        }
631
632        tempBlockWriteback = evictBlock(blk);
633    }
634
635    if (pkt->needsResponse()) {
636        pkt->makeAtomicResponse();
637    }
638
639    return lat * clockPeriod();
640}
641
642void
643BaseCache::functionalAccess(PacketPtr pkt, bool from_cpu_side)
644{
645    Addr blk_addr = pkt->getBlockAddr(blkSize);
646    bool is_secure = pkt->isSecure();
647    CacheBlk *blk = tags->findBlock(pkt->getAddr(), is_secure);
648    MSHR *mshr = mshrQueue.findMatch(blk_addr, is_secure);
649
650    pkt->pushLabel(name());
651
652    CacheBlkPrintWrapper cbpw(blk);
653
654    // Note that just because an L2/L3 has valid data doesn't mean an
655    // L1 doesn't have a more up-to-date modified copy that still
656    // needs to be found.  As a result we always update the request if
657    // we have it, but only declare it satisfied if we are the owner.
658
659    // see if we have data at all (owned or otherwise)
660    bool have_data = blk && blk->isValid()
661        && pkt->checkFunctional(&cbpw, blk_addr, is_secure, blkSize,
662                                blk->data);
663
664    // data we have is dirty if marked as such or if we have an
665    // in-service MSHR that is pending a modified line
666    bool have_dirty =
667        have_data && (blk->isDirty() ||
668                      (mshr && mshr->inService && mshr->isPendingModified()));
669
670    bool done = have_dirty ||
671        cpuSidePort.checkFunctional(pkt) ||
672        mshrQueue.checkFunctional(pkt, blk_addr) ||
673        writeBuffer.checkFunctional(pkt, blk_addr) ||
674        memSidePort.checkFunctional(pkt);
675
676    DPRINTF(CacheVerbose, "%s: %s %s%s%s\n", __func__,  pkt->print(),
677            (blk && blk->isValid()) ? "valid " : "",
678            have_data ? "data " : "", done ? "done " : "");
679
680    // We're leaving the cache, so pop cache->name() label
681    pkt->popLabel();
682
683    if (done) {
684        pkt->makeResponse();
685    } else {
686        // if it came as a request from the CPU side then make sure it
687        // continues towards the memory side
688        if (from_cpu_side) {
689            memSidePort.sendFunctional(pkt);
690        } else if (cpuSidePort.isSnooping()) {
691            // if it came from the memory side, it must be a snoop request
692            // and we should only forward it if we are forwarding snoops
693            cpuSidePort.sendFunctionalSnoop(pkt);
694        }
695    }
696}
697
698
699void
700BaseCache::cmpAndSwap(CacheBlk *blk, PacketPtr pkt)
701{
702    assert(pkt->isRequest());
703
704    uint64_t overwrite_val;
705    bool overwrite_mem;
706    uint64_t condition_val64;
707    uint32_t condition_val32;
708
709    int offset = pkt->getOffset(blkSize);
710    uint8_t *blk_data = blk->data + offset;
711
712    assert(sizeof(uint64_t) >= pkt->getSize());
713
714    overwrite_mem = true;
715    // keep a copy of our possible write value, and copy what is at the
716    // memory address into the packet
717    pkt->writeData((uint8_t *)&overwrite_val);
718    pkt->setData(blk_data);
719
720    if (pkt->req->isCondSwap()) {
721        if (pkt->getSize() == sizeof(uint64_t)) {
722            condition_val64 = pkt->req->getExtraData();
723            overwrite_mem = !std::memcmp(&condition_val64, blk_data,
724                                         sizeof(uint64_t));
725        } else if (pkt->getSize() == sizeof(uint32_t)) {
726            condition_val32 = (uint32_t)pkt->req->getExtraData();
727            overwrite_mem = !std::memcmp(&condition_val32, blk_data,
728                                         sizeof(uint32_t));
729        } else
730            panic("Invalid size for conditional read/write\n");
731    }
732
733    if (overwrite_mem) {
734        std::memcpy(blk_data, &overwrite_val, pkt->getSize());
735        blk->status |= BlkDirty;
736    }
737}
738
739QueueEntry*
740BaseCache::getNextQueueEntry()
741{
742    // Check both MSHR queue and write buffer for potential requests,
743    // note that null does not mean there is no request, it could
744    // simply be that it is not ready
745    MSHR *miss_mshr  = mshrQueue.getNext();
746    WriteQueueEntry *wq_entry = writeBuffer.getNext();
747
748    // If we got a write buffer request ready, first priority is a
749    // full write buffer, otherwise we favour the miss requests
750    if (wq_entry && (writeBuffer.isFull() || !miss_mshr)) {
751        // need to search MSHR queue for conflicting earlier miss.
752        MSHR *conflict_mshr =
753            mshrQueue.findPending(wq_entry->blkAddr,
754                                  wq_entry->isSecure);
755
756        if (conflict_mshr && conflict_mshr->order < wq_entry->order) {
757            // Service misses in order until conflict is cleared.
758            return conflict_mshr;
759
760            // @todo Note that we ignore the ready time of the conflict here
761        }
762
763        // No conflicts; issue write
764        return wq_entry;
765    } else if (miss_mshr) {
766        // need to check for conflicting earlier writeback
767        WriteQueueEntry *conflict_mshr =
768            writeBuffer.findPending(miss_mshr->blkAddr,
769                                    miss_mshr->isSecure);
770        if (conflict_mshr) {
771            // not sure why we don't check order here... it was in the
772            // original code but commented out.
773
774            // The only way this happens is if we are
775            // doing a write and we didn't have permissions
776            // then subsequently saw a writeback (owned got evicted)
777            // We need to make sure to perform the writeback first
778            // To preserve the dirty data, then we can issue the write
779
780            // should we return wq_entry here instead?  I.e. do we
781            // have to flush writes in order?  I don't think so... not
782            // for Alpha anyway.  Maybe for x86?
783            return conflict_mshr;
784
785            // @todo Note that we ignore the ready time of the conflict here
786        }
787
788        // No conflicts; issue read
789        return miss_mshr;
790    }
791
792    // fall through... no pending requests.  Try a prefetch.
793    assert(!miss_mshr && !wq_entry);
794    if (prefetcher && mshrQueue.canPrefetch()) {
795        // If we have a miss queue slot, we can try a prefetch
796        PacketPtr pkt = prefetcher->getPacket();
797        if (pkt) {
798            Addr pf_addr = pkt->getBlockAddr(blkSize);
799            if (!tags->findBlock(pf_addr, pkt->isSecure()) &&
800                !mshrQueue.findMatch(pf_addr, pkt->isSecure()) &&
801                !writeBuffer.findMatch(pf_addr, pkt->isSecure())) {
802                // Update statistic on number of prefetches issued
803                // (hwpf_mshr_misses)
804                assert(pkt->req->masterId() < system->maxMasters());
805                mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
806
807                // allocate an MSHR and return it, note
808                // that we send the packet straight away, so do not
809                // schedule the send
810                return allocateMissBuffer(pkt, curTick(), false);
811            } else {
812                // free the request and packet
813                delete pkt;
814            }
815        }
816    }
817
818    return nullptr;
819}
820
821void
822BaseCache::satisfyRequest(PacketPtr pkt, CacheBlk *blk, bool, bool)
823{
824    assert(pkt->isRequest());
825
826    assert(blk && blk->isValid());
827    // Occasionally this is not true... if we are a lower-level cache
828    // satisfying a string of Read and ReadEx requests from
829    // upper-level caches, a Read will mark the block as shared but we
830    // can satisfy a following ReadEx anyway since we can rely on the
831    // Read requester(s) to have buffered the ReadEx snoop and to
832    // invalidate their blocks after receiving them.
833    // assert(!pkt->needsWritable() || blk->isWritable());
834    assert(pkt->getOffset(blkSize) + pkt->getSize() <= blkSize);
835
836    // Check RMW operations first since both isRead() and
837    // isWrite() will be true for them
838    if (pkt->cmd == MemCmd::SwapReq) {
839        cmpAndSwap(blk, pkt);
840    } else if (pkt->isWrite()) {
841        // we have the block in a writable state and can go ahead,
842        // note that the line may be also be considered writable in
843        // downstream caches along the path to memory, but always
844        // Exclusive, and never Modified
845        assert(blk->isWritable());
846        // Write or WriteLine at the first cache with block in writable state
847        if (blk->checkWrite(pkt)) {
848            pkt->writeDataToBlock(blk->data, blkSize);
849        }
850        // Always mark the line as dirty (and thus transition to the
851        // Modified state) even if we are a failed StoreCond so we
852        // supply data to any snoops that have appended themselves to
853        // this cache before knowing the store will fail.
854        blk->status |= BlkDirty;
855        DPRINTF(CacheVerbose, "%s for %s (write)\n", __func__, pkt->print());
856    } else if (pkt->isRead()) {
857        if (pkt->isLLSC()) {
858            blk->trackLoadLocked(pkt);
859        }
860
861        // all read responses have a data payload
862        assert(pkt->hasRespData());
863        pkt->setDataFromBlock(blk->data, blkSize);
864    } else if (pkt->isUpgrade()) {
865        // sanity check
866        assert(!pkt->hasSharers());
867
868        if (blk->isDirty()) {
869            // we were in the Owned state, and a cache above us that
870            // has the line in Shared state needs to be made aware
871            // that the data it already has is in fact dirty
872            pkt->setCacheResponding();
873            blk->status &= ~BlkDirty;
874        }
875    } else {
876        assert(pkt->isInvalidate());
877        invalidateBlock(blk);
878        DPRINTF(CacheVerbose, "%s for %s (invalidation)\n", __func__,
879                pkt->print());
880    }
881}
882
883/////////////////////////////////////////////////////
884//
885// Access path: requests coming in from the CPU side
886//
887/////////////////////////////////////////////////////
888
889bool
890BaseCache::access(PacketPtr pkt, CacheBlk *&blk, Cycles &lat,
891                  PacketList &writebacks)
892{
893    // sanity check
894    assert(pkt->isRequest());
895
896    chatty_assert(!(isReadOnly && pkt->isWrite()),
897                  "Should never see a write in a read-only cache %s\n",
898                  name());
899
900    // Here lat is the value passed as parameter to accessBlock() function
901    // that can modify its value.
902    blk = tags->accessBlock(pkt->getAddr(), pkt->isSecure(), lat);
903
904    DPRINTF(Cache, "%s for %s %s\n", __func__, pkt->print(),
905            blk ? "hit " + blk->print() : "miss");
906
907    if (pkt->req->isCacheMaintenance()) {
908        // A cache maintenance operation is always forwarded to the
909        // memory below even if the block is found in dirty state.
910
911        // We defer any changes to the state of the block until we
912        // create and mark as in service the mshr for the downstream
913        // packet.
914        return false;
915    }
916
917    if (pkt->isEviction()) {
918        // We check for presence of block in above caches before issuing
919        // Writeback or CleanEvict to write buffer. Therefore the only
920        // possible cases can be of a CleanEvict packet coming from above
921        // encountering a Writeback generated in this cache peer cache and
922        // waiting in the write buffer. Cases of upper level peer caches
923        // generating CleanEvict and Writeback or simply CleanEvict and
924        // CleanEvict almost simultaneously will be caught by snoops sent out
925        // by crossbar.
926        WriteQueueEntry *wb_entry = writeBuffer.findMatch(pkt->getAddr(),
927                                                          pkt->isSecure());
928        if (wb_entry) {
929            assert(wb_entry->getNumTargets() == 1);
930            PacketPtr wbPkt = wb_entry->getTarget()->pkt;
931            assert(wbPkt->isWriteback());
932
933            if (pkt->isCleanEviction()) {
934                // The CleanEvict and WritebackClean snoops into other
935                // peer caches of the same level while traversing the
936                // crossbar. If a copy of the block is found, the
937                // packet is deleted in the crossbar. Hence, none of
938                // the other upper level caches connected to this
939                // cache have the block, so we can clear the
940                // BLOCK_CACHED flag in the Writeback if set and
941                // discard the CleanEvict by returning true.
942                wbPkt->clearBlockCached();
943                return true;
944            } else {
945                assert(pkt->cmd == MemCmd::WritebackDirty);
946                // Dirty writeback from above trumps our clean
947                // writeback... discard here
948                // Note: markInService will remove entry from writeback buffer.
949                markInService(wb_entry);
950                delete wbPkt;
951            }
952        }
953    }
954
955    // Writeback handling is special case.  We can write the block into
956    // the cache without having a writeable copy (or any copy at all).
957    if (pkt->isWriteback()) {
958        assert(blkSize == pkt->getSize());
959
960        // we could get a clean writeback while we are having
961        // outstanding accesses to a block, do the simple thing for
962        // now and drop the clean writeback so that we do not upset
963        // any ordering/decisions about ownership already taken
964        if (pkt->cmd == MemCmd::WritebackClean &&
965            mshrQueue.findMatch(pkt->getAddr(), pkt->isSecure())) {
966            DPRINTF(Cache, "Clean writeback %#llx to block with MSHR, "
967                    "dropping\n", pkt->getAddr());
968            return true;
969        }
970
971        if (!blk) {
972            // need to do a replacement
973            blk = allocateBlock(pkt->getAddr(), pkt->isSecure(), writebacks);
974            if (!blk) {
975                // no replaceable block available: give up, fwd to next level.
976                incMissCount(pkt);
977                return false;
978            }
979            tags->insertBlock(pkt, blk);
980
981            blk->status |= (BlkValid | BlkReadable);
982        }
983        // only mark the block dirty if we got a writeback command,
984        // and leave it as is for a clean writeback
985        if (pkt->cmd == MemCmd::WritebackDirty) {
986            // TODO: the coherent cache can assert(!blk->isDirty());
987            blk->status |= BlkDirty;
988        }
989        // if the packet does not have sharers, it is passing
990        // writable, and we got the writeback in Modified or Exclusive
991        // state, if not we are in the Owned or Shared state
992        if (!pkt->hasSharers()) {
993            blk->status |= BlkWritable;
994        }
995        // nothing else to do; writeback doesn't expect response
996        assert(!pkt->needsResponse());
997        pkt->writeDataToBlock(blk->data, blkSize);
998        DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
999        incHitCount(pkt);
1000        // populate the time when the block will be ready to access.
1001        blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1002            pkt->payloadDelay;
1003        return true;
1004    } else if (pkt->cmd == MemCmd::CleanEvict) {
1005        if (blk) {
1006            // Found the block in the tags, need to stop CleanEvict from
1007            // propagating further down the hierarchy. Returning true will
1008            // treat the CleanEvict like a satisfied write request and delete
1009            // it.
1010            return true;
1011        }
1012        // We didn't find the block here, propagate the CleanEvict further
1013        // down the memory hierarchy. Returning false will treat the CleanEvict
1014        // like a Writeback which could not find a replaceable block so has to
1015        // go to next level.
1016        return false;
1017    } else if (pkt->cmd == MemCmd::WriteClean) {
1018        // WriteClean handling is a special case. We can allocate a
1019        // block directly if it doesn't exist and we can update the
1020        // block immediately. The WriteClean transfers the ownership
1021        // of the block as well.
1022        assert(blkSize == pkt->getSize());
1023
1024        if (!blk) {
1025            if (pkt->writeThrough()) {
1026                // if this is a write through packet, we don't try to
1027                // allocate if the block is not present
1028                return false;
1029            } else {
1030                // a writeback that misses needs to allocate a new block
1031                blk = allocateBlock(pkt->getAddr(), pkt->isSecure(),
1032                                    writebacks);
1033                if (!blk) {
1034                    // no replaceable block available: give up, fwd to
1035                    // next level.
1036                    incMissCount(pkt);
1037                    return false;
1038                }
1039                tags->insertBlock(pkt, blk);
1040
1041                blk->status |= (BlkValid | BlkReadable);
1042            }
1043        }
1044
1045        // at this point either this is a writeback or a write-through
1046        // write clean operation and the block is already in this
1047        // cache, we need to update the data and the block flags
1048        assert(blk);
1049        // TODO: the coherent cache can assert(!blk->isDirty());
1050        if (!pkt->writeThrough()) {
1051            blk->status |= BlkDirty;
1052        }
1053        // nothing else to do; writeback doesn't expect response
1054        assert(!pkt->needsResponse());
1055        pkt->writeDataToBlock(blk->data, blkSize);
1056        DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
1057
1058        incHitCount(pkt);
1059        // populate the time when the block will be ready to access.
1060        blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
1061            pkt->payloadDelay;
1062        // if this a write-through packet it will be sent to cache
1063        // below
1064        return !pkt->writeThrough();
1065    } else if (blk && (pkt->needsWritable() ? blk->isWritable() :
1066                       blk->isReadable())) {
1067        // OK to satisfy access
1068        incHitCount(pkt);
1069        satisfyRequest(pkt, blk);
1070        maintainClusivity(pkt->fromCache(), blk);
1071
1072        return true;
1073    }
1074
1075    // Can't satisfy access normally... either no block (blk == nullptr)
1076    // or have block but need writable
1077
1078    incMissCount(pkt);
1079
1080    if (!blk && pkt->isLLSC() && pkt->isWrite()) {
1081        // complete miss on store conditional... just give up now
1082        pkt->req->setExtraData(0);
1083        return true;
1084    }
1085
1086    return false;
1087}
1088
1089void
1090BaseCache::maintainClusivity(bool from_cache, CacheBlk *blk)
1091{
1092    if (from_cache && blk && blk->isValid() && !blk->isDirty() &&
1093        clusivity == Enums::mostly_excl) {
1094        // if we have responded to a cache, and our block is still
1095        // valid, but not dirty, and this cache is mostly exclusive
1096        // with respect to the cache above, drop the block
1097        invalidateBlock(blk);
1098    }
1099}
1100
1101CacheBlk*
1102BaseCache::handleFill(PacketPtr pkt, CacheBlk *blk, PacketList &writebacks,
1103                      bool allocate)
1104{
1105    assert(pkt->isResponse() || pkt->cmd == MemCmd::WriteLineReq);
1106    Addr addr = pkt->getAddr();
1107    bool is_secure = pkt->isSecure();
1108#if TRACING_ON
1109    CacheBlk::State old_state = blk ? blk->status : 0;
1110#endif
1111
1112    // When handling a fill, we should have no writes to this line.
1113    assert(addr == pkt->getBlockAddr(blkSize));
1114    assert(!writeBuffer.findMatch(addr, is_secure));
1115
1116    if (!blk) {
1117        // better have read new data...
1118        assert(pkt->hasData());
1119
1120        // only read responses and write-line requests have data;
1121        // note that we don't write the data here for write-line - that
1122        // happens in the subsequent call to satisfyRequest
1123        assert(pkt->isRead() || pkt->cmd == MemCmd::WriteLineReq);
1124
1125        // need to do a replacement if allocating, otherwise we stick
1126        // with the temporary storage
1127        blk = allocate ? allocateBlock(addr, is_secure, writebacks) : nullptr;
1128
1129        if (!blk) {
1130            // No replaceable block or a mostly exclusive
1131            // cache... just use temporary storage to complete the
1132            // current request and then get rid of it
1133            assert(!tempBlock->isValid());
1134            blk = tempBlock;
1135            tempBlock->insert(addr, is_secure);
1136            DPRINTF(Cache, "using temp block for %#llx (%s)\n", addr,
1137                    is_secure ? "s" : "ns");
1138        } else {
1139            tags->insertBlock(pkt, blk);
1140        }
1141
1142        // we should never be overwriting a valid block
1143        assert(!blk->isValid());
1144    } else {
1145        // existing block... probably an upgrade
1146        assert(regenerateBlkAddr(blk) == addr);
1147        assert(blk->isSecure() == is_secure);
1148        // either we're getting new data or the block should already be valid
1149        assert(pkt->hasData() || blk->isValid());
1150        // don't clear block status... if block is already dirty we
1151        // don't want to lose that
1152    }
1153
1154    blk->status |= BlkValid | BlkReadable;
1155
1156    // sanity check for whole-line writes, which should always be
1157    // marked as writable as part of the fill, and then later marked
1158    // dirty as part of satisfyRequest
1159    if (pkt->cmd == MemCmd::WriteLineReq) {
1160        assert(!pkt->hasSharers());
1161    }
1162
1163    // here we deal with setting the appropriate state of the line,
1164    // and we start by looking at the hasSharers flag, and ignore the
1165    // cacheResponding flag (normally signalling dirty data) if the
1166    // packet has sharers, thus the line is never allocated as Owned
1167    // (dirty but not writable), and always ends up being either
1168    // Shared, Exclusive or Modified, see Packet::setCacheResponding
1169    // for more details
1170    if (!pkt->hasSharers()) {
1171        // we could get a writable line from memory (rather than a
1172        // cache) even in a read-only cache, note that we set this bit
1173        // even for a read-only cache, possibly revisit this decision
1174        blk->status |= BlkWritable;
1175
1176        // check if we got this via cache-to-cache transfer (i.e., from a
1177        // cache that had the block in Modified or Owned state)
1178        if (pkt->cacheResponding()) {
1179            // we got the block in Modified state, and invalidated the
1180            // owners copy
1181            blk->status |= BlkDirty;
1182
1183            chatty_assert(!isReadOnly, "Should never see dirty snoop response "
1184                          "in read-only cache %s\n", name());
1185        }
1186    }
1187
1188    DPRINTF(Cache, "Block addr %#llx (%s) moving from state %x to %s\n",
1189            addr, is_secure ? "s" : "ns", old_state, blk->print());
1190
1191    // if we got new data, copy it in (checking for a read response
1192    // and a response that has data is the same in the end)
1193    if (pkt->isRead()) {
1194        // sanity checks
1195        assert(pkt->hasData());
1196        assert(pkt->getSize() == blkSize);
1197
1198        pkt->writeDataToBlock(blk->data, blkSize);
1199    }
1200    // We pay for fillLatency here.
1201    blk->whenReady = clockEdge() + fillLatency * clockPeriod() +
1202        pkt->payloadDelay;
1203
1204    return blk;
1205}
1206
1207CacheBlk*
1208BaseCache::allocateBlock(Addr addr, bool is_secure, PacketList &writebacks)
1209{
1210    // Find replacement victim
1211    std::vector<CacheBlk*> evict_blks;
1212    CacheBlk *victim = tags->findVictim(addr, is_secure, evict_blks);
1213
1214    // It is valid to return nullptr if there is no victim
1215    if (!victim)
1216        return nullptr;
1217
1218    // Check for transient state allocations. If any of the entries listed
1219    // for eviction has a transient state, the allocation fails
1220    for (const auto& blk : evict_blks) {
1221        if (blk->isValid()) {
1222            Addr repl_addr = regenerateBlkAddr(blk);
1223            MSHR *repl_mshr = mshrQueue.findMatch(repl_addr, blk->isSecure());
1224            if (repl_mshr) {
1225                // must be an outstanding upgrade or clean request
1226                // on a block we're about to replace...
1227                assert((!blk->isWritable() && repl_mshr->needsWritable()) ||
1228                       repl_mshr->isCleaning());
1229
1230                // too hard to replace block with transient state
1231                // allocation failed, block not inserted
1232                return nullptr;
1233            }
1234        }
1235    }
1236
1237    // The victim will be replaced by a new entry, so increase the replacement
1238    // counter if a valid block is being replaced
1239    if (victim->isValid()) {
1240        DPRINTF(Cache, "replacement: replacing %#llx (%s) with %#llx "
1241                "(%s): %s\n", regenerateBlkAddr(victim),
1242                victim->isSecure() ? "s" : "ns",
1243                addr, is_secure ? "s" : "ns",
1244                victim->isDirty() ? "writeback" : "clean");
1245
1246        replacements++;
1247    }
1248
1249    // Evict valid blocks associated to this victim block
1250    for (const auto& blk : evict_blks) {
1251        if (blk->isValid()) {
1252            if (blk->wasPrefetched()) {
1253                unusedPrefetches++;
1254            }
1255
1256            evictBlock(blk, writebacks);
1257        }
1258    }
1259
1260    return victim;
1261}
1262
1263void
1264BaseCache::invalidateBlock(CacheBlk *blk)
1265{
1266    if (blk != tempBlock)
1267        tags->invalidate(blk);
1268    blk->invalidate();
1269}
1270
1271PacketPtr
1272BaseCache::writebackBlk(CacheBlk *blk)
1273{
1274    chatty_assert(!isReadOnly || writebackClean,
1275                  "Writeback from read-only cache");
1276    assert(blk && blk->isValid() && (blk->isDirty() || writebackClean));
1277
1278    writebacks[Request::wbMasterId]++;
1279
1280    RequestPtr req = std::make_shared<Request>(
1281        regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1282
1283    if (blk->isSecure())
1284        req->setFlags(Request::SECURE);
1285
1286    req->taskId(blk->task_id);
1287
1288    PacketPtr pkt =
1289        new Packet(req, blk->isDirty() ?
1290                   MemCmd::WritebackDirty : MemCmd::WritebackClean);
1291
1292    DPRINTF(Cache, "Create Writeback %s writable: %d, dirty: %d\n",
1293            pkt->print(), blk->isWritable(), blk->isDirty());
1294
1295    if (blk->isWritable()) {
1296        // not asserting shared means we pass the block in modified
1297        // state, mark our own block non-writeable
1298        blk->status &= ~BlkWritable;
1299    } else {
1300        // we are in the Owned state, tell the receiver
1301        pkt->setHasSharers();
1302    }
1303
1304    // make sure the block is not marked dirty
1305    blk->status &= ~BlkDirty;
1306
1307    pkt->allocate();
1308    pkt->setDataFromBlock(blk->data, blkSize);
1309
1310    return pkt;
1311}
1312
1313PacketPtr
1314BaseCache::writecleanBlk(CacheBlk *blk, Request::Flags dest, PacketId id)
1315{
1316    RequestPtr req = std::make_shared<Request>(
1317        regenerateBlkAddr(blk), blkSize, 0, Request::wbMasterId);
1318
1319    if (blk->isSecure()) {
1320        req->setFlags(Request::SECURE);
1321    }
1322    req->taskId(blk->task_id);
1323
1324    PacketPtr pkt = new Packet(req, MemCmd::WriteClean, blkSize, id);
1325
1326    if (dest) {
1327        req->setFlags(dest);
1328        pkt->setWriteThrough();
1329    }
1330
1331    DPRINTF(Cache, "Create %s writable: %d, dirty: %d\n", pkt->print(),
1332            blk->isWritable(), blk->isDirty());
1333
1334    if (blk->isWritable()) {
1335        // not asserting shared means we pass the block in modified
1336        // state, mark our own block non-writeable
1337        blk->status &= ~BlkWritable;
1338    } else {
1339        // we are in the Owned state, tell the receiver
1340        pkt->setHasSharers();
1341    }
1342
1343    // make sure the block is not marked dirty
1344    blk->status &= ~BlkDirty;
1345
1346    pkt->allocate();
1347    pkt->setDataFromBlock(blk->data, blkSize);
1348
1349    return pkt;
1350}
1351
1352
1353void
1354BaseCache::memWriteback()
1355{
1356    tags->forEachBlk([this](CacheBlk &blk) { writebackVisitor(blk); });
1357}
1358
1359void
1360BaseCache::memInvalidate()
1361{
1362    tags->forEachBlk([this](CacheBlk &blk) { invalidateVisitor(blk); });
1363}
1364
1365bool
1366BaseCache::isDirty() const
1367{
1368    return tags->anyBlk([](CacheBlk &blk) { return blk.isDirty(); });
1369}
1370
1371void
1372BaseCache::writebackVisitor(CacheBlk &blk)
1373{
1374    if (blk.isDirty()) {
1375        assert(blk.isValid());
1376
1377        RequestPtr request = std::make_shared<Request>(
1378            regenerateBlkAddr(&blk), blkSize, 0, Request::funcMasterId);
1379
1380        request->taskId(blk.task_id);
1381        if (blk.isSecure()) {
1382            request->setFlags(Request::SECURE);
1383        }
1384
1385        Packet packet(request, MemCmd::WriteReq);
1386        packet.dataStatic(blk.data);
1387
1388        memSidePort.sendFunctional(&packet);
1389
1390        blk.status &= ~BlkDirty;
1391    }
1392}
1393
1394void
1395BaseCache::invalidateVisitor(CacheBlk &blk)
1396{
1397    if (blk.isDirty())
1398        warn_once("Invalidating dirty cache lines. " \
1399                  "Expect things to break.\n");
1400
1401    if (blk.isValid()) {
1402        assert(!blk.isDirty());
1403        invalidateBlock(&blk);
1404    }
1405}
1406
1407Tick
1408BaseCache::nextQueueReadyTime() const
1409{
1410    Tick nextReady = std::min(mshrQueue.nextReadyTime(),
1411                              writeBuffer.nextReadyTime());
1412
1413    // Don't signal prefetch ready time if no MSHRs available
1414    // Will signal once enoguh MSHRs are deallocated
1415    if (prefetcher && mshrQueue.canPrefetch()) {
1416        nextReady = std::min(nextReady,
1417                             prefetcher->nextPrefetchReadyTime());
1418    }
1419
1420    return nextReady;
1421}
1422
1423
1424bool
1425BaseCache::sendMSHRQueuePacket(MSHR* mshr)
1426{
1427    assert(mshr);
1428
1429    // use request from 1st target
1430    PacketPtr tgt_pkt = mshr->getTarget()->pkt;
1431
1432    DPRINTF(Cache, "%s: MSHR %s\n", __func__, tgt_pkt->print());
1433
1434    CacheBlk *blk = tags->findBlock(mshr->blkAddr, mshr->isSecure);
1435
1436    // either a prefetch that is not present upstream, or a normal
1437    // MSHR request, proceed to get the packet to send downstream
1438    PacketPtr pkt = createMissPacket(tgt_pkt, blk, mshr->needsWritable());
1439
1440    mshr->isForward = (pkt == nullptr);
1441
1442    if (mshr->isForward) {
1443        // not a cache block request, but a response is expected
1444        // make copy of current packet to forward, keep current
1445        // copy for response handling
1446        pkt = new Packet(tgt_pkt, false, true);
1447        assert(!pkt->isWrite());
1448    }
1449
1450    // play it safe and append (rather than set) the sender state,
1451    // as forwarded packets may already have existing state
1452    pkt->pushSenderState(mshr);
1453
1454    if (pkt->isClean() && blk && blk->isDirty()) {
1455        // A cache clean opearation is looking for a dirty block. Mark
1456        // the packet so that the destination xbar can determine that
1457        // there will be a follow-up write packet as well.
1458        pkt->setSatisfied();
1459    }
1460
1461    if (!memSidePort.sendTimingReq(pkt)) {
1462        // we are awaiting a retry, but we
1463        // delete the packet and will be creating a new packet
1464        // when we get the opportunity
1465        delete pkt;
1466
1467        // note that we have now masked any requestBus and
1468        // schedSendEvent (we will wait for a retry before
1469        // doing anything), and this is so even if we do not
1470        // care about this packet and might override it before
1471        // it gets retried
1472        return true;
1473    } else {
1474        // As part of the call to sendTimingReq the packet is
1475        // forwarded to all neighbouring caches (and any caches
1476        // above them) as a snoop. Thus at this point we know if
1477        // any of the neighbouring caches are responding, and if
1478        // so, we know it is dirty, and we can determine if it is
1479        // being passed as Modified, making our MSHR the ordering
1480        // point
1481        bool pending_modified_resp = !pkt->hasSharers() &&
1482            pkt->cacheResponding();
1483        markInService(mshr, pending_modified_resp);
1484
1485        if (pkt->isClean() && blk && blk->isDirty()) {
1486            // A cache clean opearation is looking for a dirty
1487            // block. If a dirty block is encountered a WriteClean
1488            // will update any copies to the path to the memory
1489            // until the point of reference.
1490            DPRINTF(CacheVerbose, "%s: packet %s found block: %s\n",
1491                    __func__, pkt->print(), blk->print());
1492            PacketPtr wb_pkt = writecleanBlk(blk, pkt->req->getDest(),
1493                                             pkt->id);
1494            PacketList writebacks;
1495            writebacks.push_back(wb_pkt);
1496            doWritebacks(writebacks, 0);
1497        }
1498
1499        return false;
1500    }
1501}
1502
1503bool
1504BaseCache::sendWriteQueuePacket(WriteQueueEntry* wq_entry)
1505{
1506    assert(wq_entry);
1507
1508    // always a single target for write queue entries
1509    PacketPtr tgt_pkt = wq_entry->getTarget()->pkt;
1510
1511    DPRINTF(Cache, "%s: write %s\n", __func__, tgt_pkt->print());
1512
1513    // forward as is, both for evictions and uncacheable writes
1514    if (!memSidePort.sendTimingReq(tgt_pkt)) {
1515        // note that we have now masked any requestBus and
1516        // schedSendEvent (we will wait for a retry before
1517        // doing anything), and this is so even if we do not
1518        // care about this packet and might override it before
1519        // it gets retried
1520        return true;
1521    } else {
1522        markInService(wq_entry);
1523        return false;
1524    }
1525}
1526
1527void
1528BaseCache::serialize(CheckpointOut &cp) const
1529{
1530    bool dirty(isDirty());
1531
1532    if (dirty) {
1533        warn("*** The cache still contains dirty data. ***\n");
1534        warn("    Make sure to drain the system using the correct flags.\n");
1535        warn("    This checkpoint will not restore correctly " \
1536             "and dirty data in the cache will be lost!\n");
1537    }
1538
1539    // Since we don't checkpoint the data in the cache, any dirty data
1540    // will be lost when restoring from a checkpoint of a system that
1541    // wasn't drained properly. Flag the checkpoint as invalid if the
1542    // cache contains dirty data.
1543    bool bad_checkpoint(dirty);
1544    SERIALIZE_SCALAR(bad_checkpoint);
1545}
1546
1547void
1548BaseCache::unserialize(CheckpointIn &cp)
1549{
1550    bool bad_checkpoint;
1551    UNSERIALIZE_SCALAR(bad_checkpoint);
1552    if (bad_checkpoint) {
1553        fatal("Restoring from checkpoints with dirty caches is not "
1554              "supported in the classic memory system. Please remove any "
1555              "caches or drain them properly before taking checkpoints.\n");
1556    }
1557}
1558
1559void
1560BaseCache::regStats()
1561{
1562    MemObject::regStats();
1563
1564    using namespace Stats;
1565
1566    // Hit statistics
1567    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1568        MemCmd cmd(access_idx);
1569        const string &cstr = cmd.toString();
1570
1571        hits[access_idx]
1572            .init(system->maxMasters())
1573            .name(name() + "." + cstr + "_hits")
1574            .desc("number of " + cstr + " hits")
1575            .flags(total | nozero | nonan)
1576            ;
1577        for (int i = 0; i < system->maxMasters(); i++) {
1578            hits[access_idx].subname(i, system->getMasterName(i));
1579        }
1580    }
1581
1582// These macros make it easier to sum the right subset of commands and
1583// to change the subset of commands that are considered "demand" vs
1584// "non-demand"
1585#define SUM_DEMAND(s) \
1586    (s[MemCmd::ReadReq] + s[MemCmd::WriteReq] + s[MemCmd::WriteLineReq] + \
1587     s[MemCmd::ReadExReq] + s[MemCmd::ReadCleanReq] + s[MemCmd::ReadSharedReq])
1588
1589// should writebacks be included here?  prior code was inconsistent...
1590#define SUM_NON_DEMAND(s) \
1591    (s[MemCmd::SoftPFReq] + s[MemCmd::HardPFReq])
1592
1593    demandHits
1594        .name(name() + ".demand_hits")
1595        .desc("number of demand (read+write) hits")
1596        .flags(total | nozero | nonan)
1597        ;
1598    demandHits = SUM_DEMAND(hits);
1599    for (int i = 0; i < system->maxMasters(); i++) {
1600        demandHits.subname(i, system->getMasterName(i));
1601    }
1602
1603    overallHits
1604        .name(name() + ".overall_hits")
1605        .desc("number of overall hits")
1606        .flags(total | nozero | nonan)
1607        ;
1608    overallHits = demandHits + SUM_NON_DEMAND(hits);
1609    for (int i = 0; i < system->maxMasters(); i++) {
1610        overallHits.subname(i, system->getMasterName(i));
1611    }
1612
1613    // Miss statistics
1614    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1615        MemCmd cmd(access_idx);
1616        const string &cstr = cmd.toString();
1617
1618        misses[access_idx]
1619            .init(system->maxMasters())
1620            .name(name() + "." + cstr + "_misses")
1621            .desc("number of " + cstr + " misses")
1622            .flags(total | nozero | nonan)
1623            ;
1624        for (int i = 0; i < system->maxMasters(); i++) {
1625            misses[access_idx].subname(i, system->getMasterName(i));
1626        }
1627    }
1628
1629    demandMisses
1630        .name(name() + ".demand_misses")
1631        .desc("number of demand (read+write) misses")
1632        .flags(total | nozero | nonan)
1633        ;
1634    demandMisses = SUM_DEMAND(misses);
1635    for (int i = 0; i < system->maxMasters(); i++) {
1636        demandMisses.subname(i, system->getMasterName(i));
1637    }
1638
1639    overallMisses
1640        .name(name() + ".overall_misses")
1641        .desc("number of overall misses")
1642        .flags(total | nozero | nonan)
1643        ;
1644    overallMisses = demandMisses + SUM_NON_DEMAND(misses);
1645    for (int i = 0; i < system->maxMasters(); i++) {
1646        overallMisses.subname(i, system->getMasterName(i));
1647    }
1648
1649    // Miss latency statistics
1650    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1651        MemCmd cmd(access_idx);
1652        const string &cstr = cmd.toString();
1653
1654        missLatency[access_idx]
1655            .init(system->maxMasters())
1656            .name(name() + "." + cstr + "_miss_latency")
1657            .desc("number of " + cstr + " miss cycles")
1658            .flags(total | nozero | nonan)
1659            ;
1660        for (int i = 0; i < system->maxMasters(); i++) {
1661            missLatency[access_idx].subname(i, system->getMasterName(i));
1662        }
1663    }
1664
1665    demandMissLatency
1666        .name(name() + ".demand_miss_latency")
1667        .desc("number of demand (read+write) miss cycles")
1668        .flags(total | nozero | nonan)
1669        ;
1670    demandMissLatency = SUM_DEMAND(missLatency);
1671    for (int i = 0; i < system->maxMasters(); i++) {
1672        demandMissLatency.subname(i, system->getMasterName(i));
1673    }
1674
1675    overallMissLatency
1676        .name(name() + ".overall_miss_latency")
1677        .desc("number of overall miss cycles")
1678        .flags(total | nozero | nonan)
1679        ;
1680    overallMissLatency = demandMissLatency + SUM_NON_DEMAND(missLatency);
1681    for (int i = 0; i < system->maxMasters(); i++) {
1682        overallMissLatency.subname(i, system->getMasterName(i));
1683    }
1684
1685    // access formulas
1686    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1687        MemCmd cmd(access_idx);
1688        const string &cstr = cmd.toString();
1689
1690        accesses[access_idx]
1691            .name(name() + "." + cstr + "_accesses")
1692            .desc("number of " + cstr + " accesses(hits+misses)")
1693            .flags(total | nozero | nonan)
1694            ;
1695        accesses[access_idx] = hits[access_idx] + misses[access_idx];
1696
1697        for (int i = 0; i < system->maxMasters(); i++) {
1698            accesses[access_idx].subname(i, system->getMasterName(i));
1699        }
1700    }
1701
1702    demandAccesses
1703        .name(name() + ".demand_accesses")
1704        .desc("number of demand (read+write) accesses")
1705        .flags(total | nozero | nonan)
1706        ;
1707    demandAccesses = demandHits + demandMisses;
1708    for (int i = 0; i < system->maxMasters(); i++) {
1709        demandAccesses.subname(i, system->getMasterName(i));
1710    }
1711
1712    overallAccesses
1713        .name(name() + ".overall_accesses")
1714        .desc("number of overall (read+write) accesses")
1715        .flags(total | nozero | nonan)
1716        ;
1717    overallAccesses = overallHits + overallMisses;
1718    for (int i = 0; i < system->maxMasters(); i++) {
1719        overallAccesses.subname(i, system->getMasterName(i));
1720    }
1721
1722    // miss rate formulas
1723    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1724        MemCmd cmd(access_idx);
1725        const string &cstr = cmd.toString();
1726
1727        missRate[access_idx]
1728            .name(name() + "." + cstr + "_miss_rate")
1729            .desc("miss rate for " + cstr + " accesses")
1730            .flags(total | nozero | nonan)
1731            ;
1732        missRate[access_idx] = misses[access_idx] / accesses[access_idx];
1733
1734        for (int i = 0; i < system->maxMasters(); i++) {
1735            missRate[access_idx].subname(i, system->getMasterName(i));
1736        }
1737    }
1738
1739    demandMissRate
1740        .name(name() + ".demand_miss_rate")
1741        .desc("miss rate for demand accesses")
1742        .flags(total | nozero | nonan)
1743        ;
1744    demandMissRate = demandMisses / demandAccesses;
1745    for (int i = 0; i < system->maxMasters(); i++) {
1746        demandMissRate.subname(i, system->getMasterName(i));
1747    }
1748
1749    overallMissRate
1750        .name(name() + ".overall_miss_rate")
1751        .desc("miss rate for overall accesses")
1752        .flags(total | nozero | nonan)
1753        ;
1754    overallMissRate = overallMisses / overallAccesses;
1755    for (int i = 0; i < system->maxMasters(); i++) {
1756        overallMissRate.subname(i, system->getMasterName(i));
1757    }
1758
1759    // miss latency formulas
1760    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1761        MemCmd cmd(access_idx);
1762        const string &cstr = cmd.toString();
1763
1764        avgMissLatency[access_idx]
1765            .name(name() + "." + cstr + "_avg_miss_latency")
1766            .desc("average " + cstr + " miss latency")
1767            .flags(total | nozero | nonan)
1768            ;
1769        avgMissLatency[access_idx] =
1770            missLatency[access_idx] / misses[access_idx];
1771
1772        for (int i = 0; i < system->maxMasters(); i++) {
1773            avgMissLatency[access_idx].subname(i, system->getMasterName(i));
1774        }
1775    }
1776
1777    demandAvgMissLatency
1778        .name(name() + ".demand_avg_miss_latency")
1779        .desc("average overall miss latency")
1780        .flags(total | nozero | nonan)
1781        ;
1782    demandAvgMissLatency = demandMissLatency / demandMisses;
1783    for (int i = 0; i < system->maxMasters(); i++) {
1784        demandAvgMissLatency.subname(i, system->getMasterName(i));
1785    }
1786
1787    overallAvgMissLatency
1788        .name(name() + ".overall_avg_miss_latency")
1789        .desc("average overall miss latency")
1790        .flags(total | nozero | nonan)
1791        ;
1792    overallAvgMissLatency = overallMissLatency / overallMisses;
1793    for (int i = 0; i < system->maxMasters(); i++) {
1794        overallAvgMissLatency.subname(i, system->getMasterName(i));
1795    }
1796
1797    blocked_cycles.init(NUM_BLOCKED_CAUSES);
1798    blocked_cycles
1799        .name(name() + ".blocked_cycles")
1800        .desc("number of cycles access was blocked")
1801        .subname(Blocked_NoMSHRs, "no_mshrs")
1802        .subname(Blocked_NoTargets, "no_targets")
1803        ;
1804
1805
1806    blocked_causes.init(NUM_BLOCKED_CAUSES);
1807    blocked_causes
1808        .name(name() + ".blocked")
1809        .desc("number of cycles access was blocked")
1810        .subname(Blocked_NoMSHRs, "no_mshrs")
1811        .subname(Blocked_NoTargets, "no_targets")
1812        ;
1813
1814    avg_blocked
1815        .name(name() + ".avg_blocked_cycles")
1816        .desc("average number of cycles each access was blocked")
1817        .subname(Blocked_NoMSHRs, "no_mshrs")
1818        .subname(Blocked_NoTargets, "no_targets")
1819        ;
1820
1821    avg_blocked = blocked_cycles / blocked_causes;
1822
1823    unusedPrefetches
1824        .name(name() + ".unused_prefetches")
1825        .desc("number of HardPF blocks evicted w/o reference")
1826        .flags(nozero)
1827        ;
1828
1829    writebacks
1830        .init(system->maxMasters())
1831        .name(name() + ".writebacks")
1832        .desc("number of writebacks")
1833        .flags(total | nozero | nonan)
1834        ;
1835    for (int i = 0; i < system->maxMasters(); i++) {
1836        writebacks.subname(i, system->getMasterName(i));
1837    }
1838
1839    // MSHR statistics
1840    // MSHR hit statistics
1841    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1842        MemCmd cmd(access_idx);
1843        const string &cstr = cmd.toString();
1844
1845        mshr_hits[access_idx]
1846            .init(system->maxMasters())
1847            .name(name() + "." + cstr + "_mshr_hits")
1848            .desc("number of " + cstr + " MSHR hits")
1849            .flags(total | nozero | nonan)
1850            ;
1851        for (int i = 0; i < system->maxMasters(); i++) {
1852            mshr_hits[access_idx].subname(i, system->getMasterName(i));
1853        }
1854    }
1855
1856    demandMshrHits
1857        .name(name() + ".demand_mshr_hits")
1858        .desc("number of demand (read+write) MSHR hits")
1859        .flags(total | nozero | nonan)
1860        ;
1861    demandMshrHits = SUM_DEMAND(mshr_hits);
1862    for (int i = 0; i < system->maxMasters(); i++) {
1863        demandMshrHits.subname(i, system->getMasterName(i));
1864    }
1865
1866    overallMshrHits
1867        .name(name() + ".overall_mshr_hits")
1868        .desc("number of overall MSHR hits")
1869        .flags(total | nozero | nonan)
1870        ;
1871    overallMshrHits = demandMshrHits + SUM_NON_DEMAND(mshr_hits);
1872    for (int i = 0; i < system->maxMasters(); i++) {
1873        overallMshrHits.subname(i, system->getMasterName(i));
1874    }
1875
1876    // MSHR miss statistics
1877    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1878        MemCmd cmd(access_idx);
1879        const string &cstr = cmd.toString();
1880
1881        mshr_misses[access_idx]
1882            .init(system->maxMasters())
1883            .name(name() + "." + cstr + "_mshr_misses")
1884            .desc("number of " + cstr + " MSHR misses")
1885            .flags(total | nozero | nonan)
1886            ;
1887        for (int i = 0; i < system->maxMasters(); i++) {
1888            mshr_misses[access_idx].subname(i, system->getMasterName(i));
1889        }
1890    }
1891
1892    demandMshrMisses
1893        .name(name() + ".demand_mshr_misses")
1894        .desc("number of demand (read+write) MSHR misses")
1895        .flags(total | nozero | nonan)
1896        ;
1897    demandMshrMisses = SUM_DEMAND(mshr_misses);
1898    for (int i = 0; i < system->maxMasters(); i++) {
1899        demandMshrMisses.subname(i, system->getMasterName(i));
1900    }
1901
1902    overallMshrMisses
1903        .name(name() + ".overall_mshr_misses")
1904        .desc("number of overall MSHR misses")
1905        .flags(total | nozero | nonan)
1906        ;
1907    overallMshrMisses = demandMshrMisses + SUM_NON_DEMAND(mshr_misses);
1908    for (int i = 0; i < system->maxMasters(); i++) {
1909        overallMshrMisses.subname(i, system->getMasterName(i));
1910    }
1911
1912    // MSHR miss latency statistics
1913    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1914        MemCmd cmd(access_idx);
1915        const string &cstr = cmd.toString();
1916
1917        mshr_miss_latency[access_idx]
1918            .init(system->maxMasters())
1919            .name(name() + "." + cstr + "_mshr_miss_latency")
1920            .desc("number of " + cstr + " MSHR miss cycles")
1921            .flags(total | nozero | nonan)
1922            ;
1923        for (int i = 0; i < system->maxMasters(); i++) {
1924            mshr_miss_latency[access_idx].subname(i, system->getMasterName(i));
1925        }
1926    }
1927
1928    demandMshrMissLatency
1929        .name(name() + ".demand_mshr_miss_latency")
1930        .desc("number of demand (read+write) MSHR miss cycles")
1931        .flags(total | nozero | nonan)
1932        ;
1933    demandMshrMissLatency = SUM_DEMAND(mshr_miss_latency);
1934    for (int i = 0; i < system->maxMasters(); i++) {
1935        demandMshrMissLatency.subname(i, system->getMasterName(i));
1936    }
1937
1938    overallMshrMissLatency
1939        .name(name() + ".overall_mshr_miss_latency")
1940        .desc("number of overall MSHR miss cycles")
1941        .flags(total | nozero | nonan)
1942        ;
1943    overallMshrMissLatency =
1944        demandMshrMissLatency + SUM_NON_DEMAND(mshr_miss_latency);
1945    for (int i = 0; i < system->maxMasters(); i++) {
1946        overallMshrMissLatency.subname(i, system->getMasterName(i));
1947    }
1948
1949    // MSHR uncacheable statistics
1950    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1951        MemCmd cmd(access_idx);
1952        const string &cstr = cmd.toString();
1953
1954        mshr_uncacheable[access_idx]
1955            .init(system->maxMasters())
1956            .name(name() + "." + cstr + "_mshr_uncacheable")
1957            .desc("number of " + cstr + " MSHR uncacheable")
1958            .flags(total | nozero | nonan)
1959            ;
1960        for (int i = 0; i < system->maxMasters(); i++) {
1961            mshr_uncacheable[access_idx].subname(i, system->getMasterName(i));
1962        }
1963    }
1964
1965    overallMshrUncacheable
1966        .name(name() + ".overall_mshr_uncacheable_misses")
1967        .desc("number of overall MSHR uncacheable misses")
1968        .flags(total | nozero | nonan)
1969        ;
1970    overallMshrUncacheable =
1971        SUM_DEMAND(mshr_uncacheable) + SUM_NON_DEMAND(mshr_uncacheable);
1972    for (int i = 0; i < system->maxMasters(); i++) {
1973        overallMshrUncacheable.subname(i, system->getMasterName(i));
1974    }
1975
1976    // MSHR miss latency statistics
1977    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
1978        MemCmd cmd(access_idx);
1979        const string &cstr = cmd.toString();
1980
1981        mshr_uncacheable_lat[access_idx]
1982            .init(system->maxMasters())
1983            .name(name() + "." + cstr + "_mshr_uncacheable_latency")
1984            .desc("number of " + cstr + " MSHR uncacheable cycles")
1985            .flags(total | nozero | nonan)
1986            ;
1987        for (int i = 0; i < system->maxMasters(); i++) {
1988            mshr_uncacheable_lat[access_idx].subname(
1989                i, system->getMasterName(i));
1990        }
1991    }
1992
1993    overallMshrUncacheableLatency
1994        .name(name() + ".overall_mshr_uncacheable_latency")
1995        .desc("number of overall MSHR uncacheable cycles")
1996        .flags(total | nozero | nonan)
1997        ;
1998    overallMshrUncacheableLatency =
1999        SUM_DEMAND(mshr_uncacheable_lat) +
2000        SUM_NON_DEMAND(mshr_uncacheable_lat);
2001    for (int i = 0; i < system->maxMasters(); i++) {
2002        overallMshrUncacheableLatency.subname(i, system->getMasterName(i));
2003    }
2004
2005#if 0
2006    // MSHR access formulas
2007    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2008        MemCmd cmd(access_idx);
2009        const string &cstr = cmd.toString();
2010
2011        mshrAccesses[access_idx]
2012            .name(name() + "." + cstr + "_mshr_accesses")
2013            .desc("number of " + cstr + " mshr accesses(hits+misses)")
2014            .flags(total | nozero | nonan)
2015            ;
2016        mshrAccesses[access_idx] =
2017            mshr_hits[access_idx] + mshr_misses[access_idx]
2018            + mshr_uncacheable[access_idx];
2019    }
2020
2021    demandMshrAccesses
2022        .name(name() + ".demand_mshr_accesses")
2023        .desc("number of demand (read+write) mshr accesses")
2024        .flags(total | nozero | nonan)
2025        ;
2026    demandMshrAccesses = demandMshrHits + demandMshrMisses;
2027
2028    overallMshrAccesses
2029        .name(name() + ".overall_mshr_accesses")
2030        .desc("number of overall (read+write) mshr accesses")
2031        .flags(total | nozero | nonan)
2032        ;
2033    overallMshrAccesses = overallMshrHits + overallMshrMisses
2034        + overallMshrUncacheable;
2035#endif
2036
2037    // MSHR miss rate formulas
2038    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2039        MemCmd cmd(access_idx);
2040        const string &cstr = cmd.toString();
2041
2042        mshrMissRate[access_idx]
2043            .name(name() + "." + cstr + "_mshr_miss_rate")
2044            .desc("mshr miss rate for " + cstr + " accesses")
2045            .flags(total | nozero | nonan)
2046            ;
2047        mshrMissRate[access_idx] =
2048            mshr_misses[access_idx] / accesses[access_idx];
2049
2050        for (int i = 0; i < system->maxMasters(); i++) {
2051            mshrMissRate[access_idx].subname(i, system->getMasterName(i));
2052        }
2053    }
2054
2055    demandMshrMissRate
2056        .name(name() + ".demand_mshr_miss_rate")
2057        .desc("mshr miss rate for demand accesses")
2058        .flags(total | nozero | nonan)
2059        ;
2060    demandMshrMissRate = demandMshrMisses / demandAccesses;
2061    for (int i = 0; i < system->maxMasters(); i++) {
2062        demandMshrMissRate.subname(i, system->getMasterName(i));
2063    }
2064
2065    overallMshrMissRate
2066        .name(name() + ".overall_mshr_miss_rate")
2067        .desc("mshr miss rate for overall accesses")
2068        .flags(total | nozero | nonan)
2069        ;
2070    overallMshrMissRate = overallMshrMisses / overallAccesses;
2071    for (int i = 0; i < system->maxMasters(); i++) {
2072        overallMshrMissRate.subname(i, system->getMasterName(i));
2073    }
2074
2075    // mshrMiss latency formulas
2076    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2077        MemCmd cmd(access_idx);
2078        const string &cstr = cmd.toString();
2079
2080        avgMshrMissLatency[access_idx]
2081            .name(name() + "." + cstr + "_avg_mshr_miss_latency")
2082            .desc("average " + cstr + " mshr miss latency")
2083            .flags(total | nozero | nonan)
2084            ;
2085        avgMshrMissLatency[access_idx] =
2086            mshr_miss_latency[access_idx] / mshr_misses[access_idx];
2087
2088        for (int i = 0; i < system->maxMasters(); i++) {
2089            avgMshrMissLatency[access_idx].subname(
2090                i, system->getMasterName(i));
2091        }
2092    }
2093
2094    demandAvgMshrMissLatency
2095        .name(name() + ".demand_avg_mshr_miss_latency")
2096        .desc("average overall mshr miss latency")
2097        .flags(total | nozero | nonan)
2098        ;
2099    demandAvgMshrMissLatency = demandMshrMissLatency / demandMshrMisses;
2100    for (int i = 0; i < system->maxMasters(); i++) {
2101        demandAvgMshrMissLatency.subname(i, system->getMasterName(i));
2102    }
2103
2104    overallAvgMshrMissLatency
2105        .name(name() + ".overall_avg_mshr_miss_latency")
2106        .desc("average overall mshr miss latency")
2107        .flags(total | nozero | nonan)
2108        ;
2109    overallAvgMshrMissLatency = overallMshrMissLatency / overallMshrMisses;
2110    for (int i = 0; i < system->maxMasters(); i++) {
2111        overallAvgMshrMissLatency.subname(i, system->getMasterName(i));
2112    }
2113
2114    // mshrUncacheable latency formulas
2115    for (int access_idx = 0; access_idx < MemCmd::NUM_MEM_CMDS; ++access_idx) {
2116        MemCmd cmd(access_idx);
2117        const string &cstr = cmd.toString();
2118
2119        avgMshrUncacheableLatency[access_idx]
2120            .name(name() + "." + cstr + "_avg_mshr_uncacheable_latency")
2121            .desc("average " + cstr + " mshr uncacheable latency")
2122            .flags(total | nozero | nonan)
2123            ;
2124        avgMshrUncacheableLatency[access_idx] =
2125            mshr_uncacheable_lat[access_idx] / mshr_uncacheable[access_idx];
2126
2127        for (int i = 0; i < system->maxMasters(); i++) {
2128            avgMshrUncacheableLatency[access_idx].subname(
2129                i, system->getMasterName(i));
2130        }
2131    }
2132
2133    overallAvgMshrUncacheableLatency
2134        .name(name() + ".overall_avg_mshr_uncacheable_latency")
2135        .desc("average overall mshr uncacheable latency")
2136        .flags(total | nozero | nonan)
2137        ;
2138    overallAvgMshrUncacheableLatency =
2139        overallMshrUncacheableLatency / overallMshrUncacheable;
2140    for (int i = 0; i < system->maxMasters(); i++) {
2141        overallAvgMshrUncacheableLatency.subname(i, system->getMasterName(i));
2142    }
2143
2144    replacements
2145        .name(name() + ".replacements")
2146        .desc("number of replacements")
2147        ;
2148}
2149
2150///////////////
2151//
2152// CpuSidePort
2153//
2154///////////////
2155bool
2156BaseCache::CpuSidePort::recvTimingSnoopResp(PacketPtr pkt)
2157{
2158    // Snoops shouldn't happen when bypassing caches
2159    assert(!cache->system->bypassCaches());
2160
2161    assert(pkt->isResponse());
2162
2163    // Express snoop responses from master to slave, e.g., from L1 to L2
2164    cache->recvTimingSnoopResp(pkt);
2165    return true;
2166}
2167
2168
2169bool
2170BaseCache::CpuSidePort::tryTiming(PacketPtr pkt)
2171{
2172    if (cache->system->bypassCaches() || pkt->isExpressSnoop()) {
2173        // always let express snoop packets through even if blocked
2174        return true;
2175    } else if (blocked || mustSendRetry) {
2176        // either already committed to send a retry, or blocked
2177        mustSendRetry = true;
2178        return false;
2179    }
2180    mustSendRetry = false;
2181    return true;
2182}
2183
2184bool
2185BaseCache::CpuSidePort::recvTimingReq(PacketPtr pkt)
2186{
2187    assert(pkt->isRequest());
2188
2189    if (cache->system->bypassCaches()) {
2190        // Just forward the packet if caches are disabled.
2191        // @todo This should really enqueue the packet rather
2192        bool M5_VAR_USED success = cache->memSidePort.sendTimingReq(pkt);
2193        assert(success);
2194        return true;
2195    } else if (tryTiming(pkt)) {
2196        cache->recvTimingReq(pkt);
2197        return true;
2198    }
2199    return false;
2200}
2201
2202Tick
2203BaseCache::CpuSidePort::recvAtomic(PacketPtr pkt)
2204{
2205    if (cache->system->bypassCaches()) {
2206        // Forward the request if the system is in cache bypass mode.
2207        return cache->memSidePort.sendAtomic(pkt);
2208    } else {
2209        return cache->recvAtomic(pkt);
2210    }
2211}
2212
2213void
2214BaseCache::CpuSidePort::recvFunctional(PacketPtr pkt)
2215{
2216    if (cache->system->bypassCaches()) {
2217        // The cache should be flushed if we are in cache bypass mode,
2218        // so we don't need to check if we need to update anything.
2219        cache->memSidePort.sendFunctional(pkt);
2220        return;
2221    }
2222
2223    // functional request
2224    cache->functionalAccess(pkt, true);
2225}
2226
2227AddrRangeList
2228BaseCache::CpuSidePort::getAddrRanges() const
2229{
2230    return cache->getAddrRanges();
2231}
2232
2233
2234BaseCache::
2235CpuSidePort::CpuSidePort(const std::string &_name, BaseCache *_cache,
2236                         const std::string &_label)
2237    : CacheSlavePort(_name, _cache, _label), cache(_cache)
2238{
2239}
2240
2241///////////////
2242//
2243// MemSidePort
2244//
2245///////////////
2246bool
2247BaseCache::MemSidePort::recvTimingResp(PacketPtr pkt)
2248{
2249    cache->recvTimingResp(pkt);
2250    return true;
2251}
2252
2253// Express snooping requests to memside port
2254void
2255BaseCache::MemSidePort::recvTimingSnoopReq(PacketPtr pkt)
2256{
2257    // Snoops shouldn't happen when bypassing caches
2258    assert(!cache->system->bypassCaches());
2259
2260    // handle snooping requests
2261    cache->recvTimingSnoopReq(pkt);
2262}
2263
2264Tick
2265BaseCache::MemSidePort::recvAtomicSnoop(PacketPtr pkt)
2266{
2267    // Snoops shouldn't happen when bypassing caches
2268    assert(!cache->system->bypassCaches());
2269
2270    return cache->recvAtomicSnoop(pkt);
2271}
2272
2273void
2274BaseCache::MemSidePort::recvFunctionalSnoop(PacketPtr pkt)
2275{
2276    // Snoops shouldn't happen when bypassing caches
2277    assert(!cache->system->bypassCaches());
2278
2279    // functional snoop (note that in contrast to atomic we don't have
2280    // a specific functionalSnoop method, as they have the same
2281    // behaviour regardless)
2282    cache->functionalAccess(pkt, false);
2283}
2284
2285void
2286BaseCache::CacheReqPacketQueue::sendDeferredPacket()
2287{
2288    // sanity check
2289    assert(!waitingOnRetry);
2290
2291    // there should never be any deferred request packets in the
2292    // queue, instead we resly on the cache to provide the packets
2293    // from the MSHR queue or write queue
2294    assert(deferredPacketReadyTime() == MaxTick);
2295
2296    // check for request packets (requests & writebacks)
2297    QueueEntry* entry = cache.getNextQueueEntry();
2298
2299    if (!entry) {
2300        // can happen if e.g. we attempt a writeback and fail, but
2301        // before the retry, the writeback is eliminated because
2302        // we snoop another cache's ReadEx.
2303    } else {
2304        // let our snoop responses go first if there are responses to
2305        // the same addresses
2306        if (checkConflictingSnoop(entry->blkAddr)) {
2307            return;
2308        }
2309        waitingOnRetry = entry->sendPacket(cache);
2310    }
2311
2312    // if we succeeded and are not waiting for a retry, schedule the
2313    // next send considering when the next queue is ready, note that
2314    // snoop responses have their own packet queue and thus schedule
2315    // their own events
2316    if (!waitingOnRetry) {
2317        schedSendEvent(cache.nextQueueReadyTime());
2318    }
2319}
2320
2321BaseCache::MemSidePort::MemSidePort(const std::string &_name,
2322                                    BaseCache *_cache,
2323                                    const std::string &_label)
2324    : CacheMasterPort(_name, _cache, _reqQueue, _snoopRespQueue),
2325      _reqQueue(*_cache, *this, _snoopRespQueue, _label),
2326      _snoopRespQueue(*_cache, *this, _label), cache(_cache)
2327{
2328}
2329