54#include "mem/packet.hh"
55#include "mem/request.hh"
56
57template<class Impl>
58LSQUnit<Impl>::WritebackEvent::WritebackEvent(DynInstPtr &_inst, PacketPtr _pkt,
59 LSQUnit *lsq_ptr)
60 : Event(Default_Pri, AutoDelete),
61 inst(_inst), pkt(_pkt), lsqPtr(lsq_ptr)
62{
63}
64
65template<class Impl>
66void
67LSQUnit<Impl>::WritebackEvent::process()
68{
69 assert(!lsqPtr->cpu->switchedOut());
70
71 lsqPtr->writeback(inst, pkt);
72
73 if (pkt->senderState)
74 delete pkt->senderState;
75
76 delete pkt->req;
77 delete pkt;
78}
79
80template<class Impl>
81const char *
82LSQUnit<Impl>::WritebackEvent::description() const
83{
84 return "Store writeback";
85}
86
87template<class Impl>
88void
89LSQUnit<Impl>::completeDataAccess(PacketPtr pkt)
90{
91 LSQSenderState *state = dynamic_cast<LSQSenderState *>(pkt->senderState);
92 DynInstPtr inst = state->inst;
93 DPRINTF(IEW, "Writeback event [sn:%lli].\n", inst->seqNum);
94 DPRINTF(Activity, "Activity: Writeback event [sn:%lli].\n", inst->seqNum);
95
96 //iewStage->ldstQueue.removeMSHR(inst->threadNumber,inst->seqNum);
97
98 // If this is a split access, wait until all packets are received.
99 if (TheISA::HasUnalignedMemAcc && !state->complete()) {
100 delete pkt->req;
101 delete pkt;
102 return;
103 }
104
105 assert(!cpu->switchedOut());
106 if (inst->isSquashed()) {
107 iewStage->decrWb(inst->seqNum);
108 } else {
109 if (!state->noWB) {
110 if (!TheISA::HasUnalignedMemAcc || !state->isSplit ||
111 !state->isLoad) {
112 writeback(inst, pkt);
113 } else {
114 writeback(inst, state->mainPkt);
115 }
116 }
117
118 if (inst->isStore()) {
119 completeStore(state->idx);
120 }
121 }
122
123 if (TheISA::HasUnalignedMemAcc && state->isSplit && state->isLoad) {
124 delete state->mainPkt->req;
125 delete state->mainPkt;
126 }
127 delete state;
128 delete pkt->req;
129 delete pkt;
130}
131
132template <class Impl>
133LSQUnit<Impl>::LSQUnit()
134 : loads(0), stores(0), storesToWB(0), cacheBlockMask(0), stalled(false),
135 isStoreBlocked(false), isLoadBlocked(false),
136 loadBlockedHandled(false), storeInFlight(false), hasPendingPkt(false)
137{
138}
139
140template<class Impl>
141void
142LSQUnit<Impl>::init(O3CPU *cpu_ptr, IEW *iew_ptr, DerivO3CPUParams *params,
143 LSQ *lsq_ptr, unsigned maxLQEntries, unsigned maxSQEntries,
144 unsigned id)
145{
146 cpu = cpu_ptr;
147 iewStage = iew_ptr;
148
149 DPRINTF(LSQUnit, "Creating LSQUnit%i object.\n",id);
150
151 lsq = lsq_ptr;
152
153 lsqID = id;
154
155 // Add 1 for the sentinel entry (they are circular queues).
156 LQEntries = maxLQEntries + 1;
157 SQEntries = maxSQEntries + 1;
158
159 loadQueue.resize(LQEntries);
160 storeQueue.resize(SQEntries);
161
162 depCheckShift = params->LSQDepCheckShift;
163 checkLoads = params->LSQCheckLoads;
164 cachePorts = params->cachePorts;
165 needsTSO = params->needsTSO;
166
167 resetState();
168}
169
170
171template<class Impl>
172void
173LSQUnit<Impl>::resetState()
174{
175 loads = stores = storesToWB = 0;
176
177 loadHead = loadTail = 0;
178
179 storeHead = storeWBIdx = storeTail = 0;
180
181 usedPorts = 0;
182
183 retryPkt = NULL;
184 memDepViolator = NULL;
185
186 blockedLoadSeqNum = 0;
187
188 stalled = false;
189 isLoadBlocked = false;
190 loadBlockedHandled = false;
191
192 cacheBlockMask = 0;
193}
194
195template<class Impl>
196std::string
197LSQUnit<Impl>::name() const
198{
199 if (Impl::MaxThreads == 1) {
200 return iewStage->name() + ".lsq";
201 } else {
202 return iewStage->name() + ".lsq.thread" + to_string(lsqID);
203 }
204}
205
206template<class Impl>
207void
208LSQUnit<Impl>::regStats()
209{
210 lsqForwLoads
211 .name(name() + ".forwLoads")
212 .desc("Number of loads that had data forwarded from stores");
213
214 invAddrLoads
215 .name(name() + ".invAddrLoads")
216 .desc("Number of loads ignored due to an invalid address");
217
218 lsqSquashedLoads
219 .name(name() + ".squashedLoads")
220 .desc("Number of loads squashed");
221
222 lsqIgnoredResponses
223 .name(name() + ".ignoredResponses")
224 .desc("Number of memory responses ignored because the instruction is squashed");
225
226 lsqMemOrderViolation
227 .name(name() + ".memOrderViolation")
228 .desc("Number of memory ordering violations");
229
230 lsqSquashedStores
231 .name(name() + ".squashedStores")
232 .desc("Number of stores squashed");
233
234 invAddrSwpfs
235 .name(name() + ".invAddrSwpfs")
236 .desc("Number of software prefetches ignored due to an invalid address");
237
238 lsqBlockedLoads
239 .name(name() + ".blockedLoads")
240 .desc("Number of blocked loads due to partial load-store forwarding");
241
242 lsqRescheduledLoads
243 .name(name() + ".rescheduledLoads")
244 .desc("Number of loads that were rescheduled");
245
246 lsqCacheBlocked
247 .name(name() + ".cacheBlocked")
248 .desc("Number of times an access to memory failed due to the cache being blocked");
249}
250
251template<class Impl>
252void
253LSQUnit<Impl>::setDcachePort(MasterPort *dcache_port)
254{
255 dcachePort = dcache_port;
256}
257
258template<class Impl>
259void
260LSQUnit<Impl>::clearLQ()
261{
262 loadQueue.clear();
263}
264
265template<class Impl>
266void
267LSQUnit<Impl>::clearSQ()
268{
269 storeQueue.clear();
270}
271
272template<class Impl>
273void
274LSQUnit<Impl>::drainSanityCheck() const
275{
276 for (int i = 0; i < loadQueue.size(); ++i)
277 assert(!loadQueue[i]);
278
279 assert(storesToWB == 0);
280 assert(!retryPkt);
281}
282
283template<class Impl>
284void
285LSQUnit<Impl>::takeOverFrom()
286{
287 resetState();
288}
289
290template<class Impl>
291void
292LSQUnit<Impl>::resizeLQ(unsigned size)
293{
294 unsigned size_plus_sentinel = size + 1;
295 assert(size_plus_sentinel >= LQEntries);
296
297 if (size_plus_sentinel > LQEntries) {
298 while (size_plus_sentinel > loadQueue.size()) {
299 DynInstPtr dummy;
300 loadQueue.push_back(dummy);
301 LQEntries++;
302 }
303 } else {
304 LQEntries = size_plus_sentinel;
305 }
306
307}
308
309template<class Impl>
310void
311LSQUnit<Impl>::resizeSQ(unsigned size)
312{
313 unsigned size_plus_sentinel = size + 1;
314 if (size_plus_sentinel > SQEntries) {
315 while (size_plus_sentinel > storeQueue.size()) {
316 SQEntry dummy;
317 storeQueue.push_back(dummy);
318 SQEntries++;
319 }
320 } else {
321 SQEntries = size_plus_sentinel;
322 }
323}
324
325template <class Impl>
326void
327LSQUnit<Impl>::insert(DynInstPtr &inst)
328{
329 assert(inst->isMemRef());
330
331 assert(inst->isLoad() || inst->isStore());
332
333 if (inst->isLoad()) {
334 insertLoad(inst);
335 } else {
336 insertStore(inst);
337 }
338
339 inst->setInLSQ();
340}
341
342template <class Impl>
343void
344LSQUnit<Impl>::insertLoad(DynInstPtr &load_inst)
345{
346 assert((loadTail + 1) % LQEntries != loadHead);
347 assert(loads < LQEntries);
348
349 DPRINTF(LSQUnit, "Inserting load PC %s, idx:%i [sn:%lli]\n",
350 load_inst->pcState(), loadTail, load_inst->seqNum);
351
352 load_inst->lqIdx = loadTail;
353
354 if (stores == 0) {
355 load_inst->sqIdx = -1;
356 } else {
357 load_inst->sqIdx = storeTail;
358 }
359
360 loadQueue[loadTail] = load_inst;
361
362 incrLdIdx(loadTail);
363
364 ++loads;
365}
366
367template <class Impl>
368void
369LSQUnit<Impl>::insertStore(DynInstPtr &store_inst)
370{
371 // Make sure it is not full before inserting an instruction.
372 assert((storeTail + 1) % SQEntries != storeHead);
373 assert(stores < SQEntries);
374
375 DPRINTF(LSQUnit, "Inserting store PC %s, idx:%i [sn:%lli]\n",
376 store_inst->pcState(), storeTail, store_inst->seqNum);
377
378 store_inst->sqIdx = storeTail;
379 store_inst->lqIdx = loadTail;
380
381 storeQueue[storeTail] = SQEntry(store_inst);
382
383 incrStIdx(storeTail);
384
385 ++stores;
386}
387
388template <class Impl>
389typename Impl::DynInstPtr
390LSQUnit<Impl>::getMemDepViolator()
391{
392 DynInstPtr temp = memDepViolator;
393
394 memDepViolator = NULL;
395
396 return temp;
397}
398
399template <class Impl>
400unsigned
401LSQUnit<Impl>::numFreeEntries()
402{
403 unsigned free_lq_entries = LQEntries - loads;
404 unsigned free_sq_entries = SQEntries - stores;
405
406 // Both the LQ and SQ entries have an extra dummy entry to differentiate
407 // empty/full conditions. Subtract 1 from the free entries.
408 if (free_lq_entries < free_sq_entries) {
409 return free_lq_entries - 1;
410 } else {
411 return free_sq_entries - 1;
412 }
413}
414
415template <class Impl>
416void
417LSQUnit<Impl>::checkSnoop(PacketPtr pkt)
418{
419 int load_idx = loadHead;
420
421 if (!cacheBlockMask) {
422 assert(dcachePort);
423 Addr bs = dcachePort->peerBlockSize();
424
425 // Make sure we actually got a size
426 assert(bs != 0);
427
428 cacheBlockMask = ~(bs - 1);
429 }
430
431 // Unlock the cpu-local monitor when the CPU sees a snoop to a locked
432 // address. The CPU can speculatively execute a LL operation after a pending
433 // SC operation in the pipeline and that can make the cache monitor the CPU
434 // is connected to valid while it really shouldn't be.
435 for (int x = 0; x < cpu->numActiveThreads(); x++) {
436 ThreadContext *tc = cpu->getContext(x);
437 bool no_squash = cpu->thread[x]->noSquashFromTC;
438 cpu->thread[x]->noSquashFromTC = true;
439 TheISA::handleLockedSnoop(tc, pkt, cacheBlockMask);
440 cpu->thread[x]->noSquashFromTC = no_squash;
441 }
442
443 // If this is the only load in the LSQ we don't care
444 if (load_idx == loadTail)
445 return;
446 incrLdIdx(load_idx);
447
448 DPRINTF(LSQUnit, "Got snoop for address %#x\n", pkt->getAddr());
449 Addr invalidate_addr = pkt->getAddr() & cacheBlockMask;
450 while (load_idx != loadTail) {
451 DynInstPtr ld_inst = loadQueue[load_idx];
452
453 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) {
454 incrLdIdx(load_idx);
455 continue;
456 }
457
458 Addr load_addr = ld_inst->physEffAddr & cacheBlockMask;
459 DPRINTF(LSQUnit, "-- inst [sn:%lli] load_addr: %#x to pktAddr:%#x\n",
460 ld_inst->seqNum, load_addr, invalidate_addr);
461
462 if (load_addr == invalidate_addr) {
463 if (ld_inst->possibleLoadViolation()) {
464 DPRINTF(LSQUnit, "Conflicting load at addr %#x [sn:%lli]\n",
465 ld_inst->physEffAddr, pkt->getAddr(), ld_inst->seqNum);
466
467 // Mark the load for re-execution
468 ld_inst->fault = new ReExec;
469 } else {
470 // If a older load checks this and it's true
471 // then we might have missed the snoop
472 // in which case we need to invalidate to be sure
473 ld_inst->hitExternalSnoop(true);
474 }
475 }
476 incrLdIdx(load_idx);
477 }
478 return;
479}
480
481template <class Impl>
482Fault
483LSQUnit<Impl>::checkViolations(int load_idx, DynInstPtr &inst)
484{
485 Addr inst_eff_addr1 = inst->effAddr >> depCheckShift;
486 Addr inst_eff_addr2 = (inst->effAddr + inst->effSize - 1) >> depCheckShift;
487
488 /** @todo in theory you only need to check an instruction that has executed
489 * however, there isn't a good way in the pipeline at the moment to check
490 * all instructions that will execute before the store writes back. Thus,
491 * like the implementation that came before it, we're overly conservative.
492 */
493 while (load_idx != loadTail) {
494 DynInstPtr ld_inst = loadQueue[load_idx];
495 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) {
496 incrLdIdx(load_idx);
497 continue;
498 }
499
500 Addr ld_eff_addr1 = ld_inst->effAddr >> depCheckShift;
501 Addr ld_eff_addr2 =
502 (ld_inst->effAddr + ld_inst->effSize - 1) >> depCheckShift;
503
504 if (inst_eff_addr2 >= ld_eff_addr1 && inst_eff_addr1 <= ld_eff_addr2) {
505 if (inst->isLoad()) {
506 // If this load is to the same block as an external snoop
507 // invalidate that we've observed then the load needs to be
508 // squashed as it could have newer data
509 if (ld_inst->hitExternalSnoop()) {
510 if (!memDepViolator ||
511 ld_inst->seqNum < memDepViolator->seqNum) {
512 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] "
513 "and [sn:%lli] at address %#x\n",
514 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
515 memDepViolator = ld_inst;
516
517 ++lsqMemOrderViolation;
518
519 return new GenericISA::M5PanicFault(
520 "Detected fault with inst [sn:%lli] and "
521 "[sn:%lli] at address %#x\n",
522 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
523 }
524 }
525
526 // Otherwise, mark the load has a possible load violation
527 // and if we see a snoop before it's commited, we need to squash
528 ld_inst->possibleLoadViolation(true);
529 DPRINTF(LSQUnit, "Found possible load violaiton at addr: %#x"
530 " between instructions [sn:%lli] and [sn:%lli]\n",
531 inst_eff_addr1, inst->seqNum, ld_inst->seqNum);
532 } else {
533 // A load/store incorrectly passed this store.
534 // Check if we already have a violator, or if it's newer
535 // squash and refetch.
536 if (memDepViolator && ld_inst->seqNum > memDepViolator->seqNum)
537 break;
538
539 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] and "
540 "[sn:%lli] at address %#x\n",
541 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
542 memDepViolator = ld_inst;
543
544 ++lsqMemOrderViolation;
545
546 return new GenericISA::M5PanicFault("Detected fault with "
547 "inst [sn:%lli] and [sn:%lli] at address %#x\n",
548 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
549 }
550 }
551
552 incrLdIdx(load_idx);
553 }
554 return NoFault;
555}
556
557
558
559
560template <class Impl>
561Fault
562LSQUnit<Impl>::executeLoad(DynInstPtr &inst)
563{
564 using namespace TheISA;
565 // Execute a specific load.
566 Fault load_fault = NoFault;
567
568 DPRINTF(LSQUnit, "Executing load PC %s, [sn:%lli]\n",
569 inst->pcState(), inst->seqNum);
570
571 assert(!inst->isSquashed());
572
573 load_fault = inst->initiateAcc();
574
575 if (inst->isTranslationDelayed() &&
576 load_fault == NoFault)
577 return load_fault;
578
579 // If the instruction faulted or predicated false, then we need to send it
580 // along to commit without the instruction completing.
581 if (load_fault != NoFault || inst->readPredicate() == false) {
582 // Send this instruction to commit, also make sure iew stage
583 // realizes there is activity.
584 // Mark it as executed unless it is an uncached load that
585 // needs to hit the head of commit.
586 if (inst->readPredicate() == false)
587 inst->forwardOldRegs();
588 DPRINTF(LSQUnit, "Load [sn:%lli] not executed from %s\n",
589 inst->seqNum,
590 (load_fault != NoFault ? "fault" : "predication"));
591 if (!(inst->hasRequest() && inst->uncacheable()) ||
592 inst->isAtCommit()) {
593 inst->setExecuted();
594 }
595 iewStage->instToCommit(inst);
596 iewStage->activityThisCycle();
597 } else if (!loadBlocked()) {
598 assert(inst->effAddrValid());
599 int load_idx = inst->lqIdx;
600 incrLdIdx(load_idx);
601
602 if (checkLoads)
603 return checkViolations(load_idx, inst);
604 }
605
606 return load_fault;
607}
608
609template <class Impl>
610Fault
611LSQUnit<Impl>::executeStore(DynInstPtr &store_inst)
612{
613 using namespace TheISA;
614 // Make sure that a store exists.
615 assert(stores != 0);
616
617 int store_idx = store_inst->sqIdx;
618
619 DPRINTF(LSQUnit, "Executing store PC %s [sn:%lli]\n",
620 store_inst->pcState(), store_inst->seqNum);
621
622 assert(!store_inst->isSquashed());
623
624 // Check the recently completed loads to see if any match this store's
625 // address. If so, then we have a memory ordering violation.
626 int load_idx = store_inst->lqIdx;
627
628 Fault store_fault = store_inst->initiateAcc();
629
630 if (store_inst->isTranslationDelayed() &&
631 store_fault == NoFault)
632 return store_fault;
633
634 if (store_inst->readPredicate() == false)
635 store_inst->forwardOldRegs();
636
637 if (storeQueue[store_idx].size == 0) {
638 DPRINTF(LSQUnit,"Fault on Store PC %s, [sn:%lli], Size = 0\n",
639 store_inst->pcState(), store_inst->seqNum);
640
641 return store_fault;
642 } else if (store_inst->readPredicate() == false) {
643 DPRINTF(LSQUnit, "Store [sn:%lli] not executed from predication\n",
644 store_inst->seqNum);
645 return store_fault;
646 }
647
648 assert(store_fault == NoFault);
649
650 if (store_inst->isStoreConditional()) {
651 // Store conditionals need to set themselves as able to
652 // writeback if we haven't had a fault by here.
653 storeQueue[store_idx].canWB = true;
654
655 ++storesToWB;
656 }
657
658 return checkViolations(load_idx, store_inst);
659
660}
661
662template <class Impl>
663void
664LSQUnit<Impl>::commitLoad()
665{
666 assert(loadQueue[loadHead]);
667
668 DPRINTF(LSQUnit, "Committing head load instruction, PC %s\n",
669 loadQueue[loadHead]->pcState());
670
671 loadQueue[loadHead] = NULL;
672
673 incrLdIdx(loadHead);
674
675 --loads;
676}
677
678template <class Impl>
679void
680LSQUnit<Impl>::commitLoads(InstSeqNum &youngest_inst)
681{
682 assert(loads == 0 || loadQueue[loadHead]);
683
684 while (loads != 0 && loadQueue[loadHead]->seqNum <= youngest_inst) {
685 commitLoad();
686 }
687}
688
689template <class Impl>
690void
691LSQUnit<Impl>::commitStores(InstSeqNum &youngest_inst)
692{
693 assert(stores == 0 || storeQueue[storeHead].inst);
694
695 int store_idx = storeHead;
696
697 while (store_idx != storeTail) {
698 assert(storeQueue[store_idx].inst);
699 // Mark any stores that are now committed and have not yet
700 // been marked as able to write back.
701 if (!storeQueue[store_idx].canWB) {
702 if (storeQueue[store_idx].inst->seqNum > youngest_inst) {
703 break;
704 }
705 DPRINTF(LSQUnit, "Marking store as able to write back, PC "
706 "%s [sn:%lli]\n",
707 storeQueue[store_idx].inst->pcState(),
708 storeQueue[store_idx].inst->seqNum);
709
710 storeQueue[store_idx].canWB = true;
711
712 ++storesToWB;
713 }
714
715 incrStIdx(store_idx);
716 }
717}
718
719template <class Impl>
720void
721LSQUnit<Impl>::writebackPendingStore()
722{
723 if (hasPendingPkt) {
724 assert(pendingPkt != NULL);
725
726 // If the cache is blocked, this will store the packet for retry.
727 if (sendStore(pendingPkt)) {
728 storePostSend(pendingPkt);
729 }
730 pendingPkt = NULL;
731 hasPendingPkt = false;
732 }
733}
734
735template <class Impl>
736void
737LSQUnit<Impl>::writebackStores()
738{
739 // First writeback the second packet from any split store that didn't
740 // complete last cycle because there weren't enough cache ports available.
741 if (TheISA::HasUnalignedMemAcc) {
742 writebackPendingStore();
743 }
744
745 while (storesToWB > 0 &&
746 storeWBIdx != storeTail &&
747 storeQueue[storeWBIdx].inst &&
748 storeQueue[storeWBIdx].canWB &&
749 ((!needsTSO) || (!storeInFlight)) &&
750 usedPorts < cachePorts) {
751
752 if (isStoreBlocked || lsq->cacheBlocked()) {
753 DPRINTF(LSQUnit, "Unable to write back any more stores, cache"
754 " is blocked!\n");
755 break;
756 }
757
758 // Store didn't write any data so no need to write it back to
759 // memory.
760 if (storeQueue[storeWBIdx].size == 0) {
761 completeStore(storeWBIdx);
762
763 incrStIdx(storeWBIdx);
764
765 continue;
766 }
767
768 ++usedPorts;
769
770 if (storeQueue[storeWBIdx].inst->isDataPrefetch()) {
771 incrStIdx(storeWBIdx);
772
773 continue;
774 }
775
776 assert(storeQueue[storeWBIdx].req);
777 assert(!storeQueue[storeWBIdx].committed);
778
779 if (TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit) {
780 assert(storeQueue[storeWBIdx].sreqLow);
781 assert(storeQueue[storeWBIdx].sreqHigh);
782 }
783
784 DynInstPtr inst = storeQueue[storeWBIdx].inst;
785
786 Request *req = storeQueue[storeWBIdx].req;
787 RequestPtr sreqLow = storeQueue[storeWBIdx].sreqLow;
788 RequestPtr sreqHigh = storeQueue[storeWBIdx].sreqHigh;
789
790 storeQueue[storeWBIdx].committed = true;
791
792 assert(!inst->memData);
793 inst->memData = new uint8_t[64];
794
795 memcpy(inst->memData, storeQueue[storeWBIdx].data, req->getSize());
796
797 MemCmd command =
798 req->isSwap() ? MemCmd::SwapReq :
799 (req->isLLSC() ? MemCmd::StoreCondReq : MemCmd::WriteReq);
800 PacketPtr data_pkt;
801 PacketPtr snd_data_pkt = NULL;
802
803 LSQSenderState *state = new LSQSenderState;
804 state->isLoad = false;
805 state->idx = storeWBIdx;
806 state->inst = inst;
807
808 if (!TheISA::HasUnalignedMemAcc || !storeQueue[storeWBIdx].isSplit) {
809
810 // Build a single data packet if the store isn't split.
811 data_pkt = new Packet(req, command);
812 data_pkt->dataStatic(inst->memData);
813 data_pkt->senderState = state;
814 } else {
815 // Create two packets if the store is split in two.
816 data_pkt = new Packet(sreqLow, command);
817 snd_data_pkt = new Packet(sreqHigh, command);
818
819 data_pkt->dataStatic(inst->memData);
820 snd_data_pkt->dataStatic(inst->memData + sreqLow->getSize());
821
822 data_pkt->senderState = state;
823 snd_data_pkt->senderState = state;
824
825 state->isSplit = true;
826 state->outstanding = 2;
827
828 // Can delete the main request now.
829 delete req;
830 req = sreqLow;
831 }
832
833 DPRINTF(LSQUnit, "D-Cache: Writing back store idx:%i PC:%s "
834 "to Addr:%#x, data:%#x [sn:%lli]\n",
835 storeWBIdx, inst->pcState(),
836 req->getPaddr(), (int)*(inst->memData),
837 inst->seqNum);
838
839 // @todo: Remove this SC hack once the memory system handles it.
840 if (inst->isStoreConditional()) {
841 assert(!storeQueue[storeWBIdx].isSplit);
842 // Disable recording the result temporarily. Writing to
843 // misc regs normally updates the result, but this is not
844 // the desired behavior when handling store conditionals.
845 inst->recordResult(false);
846 bool success = TheISA::handleLockedWrite(inst.get(), req);
847 inst->recordResult(true);
848
849 if (!success) {
850 // Instantly complete this store.
851 DPRINTF(LSQUnit, "Store conditional [sn:%lli] failed. "
852 "Instantly completing it.\n",
853 inst->seqNum);
854 WritebackEvent *wb = new WritebackEvent(inst, data_pkt, this);
855 cpu->schedule(wb, curTick() + 1);
856 if (cpu->checker) {
857 // Make sure to set the LLSC data for verification
858 // if checker is loaded
859 inst->reqToVerify->setExtraData(0);
860 inst->completeAcc(data_pkt);
861 }
862 completeStore(storeWBIdx);
863 incrStIdx(storeWBIdx);
864 continue;
865 }
866 } else {
867 // Non-store conditionals do not need a writeback.
868 state->noWB = true;
869 }
870
871 bool split =
872 TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit;
873
874 ThreadContext *thread = cpu->tcBase(lsqID);
875
876 if (req->isMmappedIpr()) {
877 assert(!inst->isStoreConditional());
878 TheISA::handleIprWrite(thread, data_pkt);
879 delete data_pkt;
880 if (split) {
881 assert(snd_data_pkt->req->isMmappedIpr());
882 TheISA::handleIprWrite(thread, snd_data_pkt);
883 delete snd_data_pkt;
884 delete sreqLow;
885 delete sreqHigh;
886 }
887 delete state;
888 delete req;
889 completeStore(storeWBIdx);
890 incrStIdx(storeWBIdx);
891 } else if (!sendStore(data_pkt)) {
892 DPRINTF(IEW, "D-Cache became blocked when writing [sn:%lli], will"
893 "retry later\n",
894 inst->seqNum);
895
896 // Need to store the second packet, if split.
897 if (split) {
898 state->pktToSend = true;
899 state->pendingPacket = snd_data_pkt;
900 }
901 } else {
902
903 // If split, try to send the second packet too
904 if (split) {
905 assert(snd_data_pkt);
906
907 // Ensure there are enough ports to use.
908 if (usedPorts < cachePorts) {
909 ++usedPorts;
910 if (sendStore(snd_data_pkt)) {
911 storePostSend(snd_data_pkt);
912 } else {
913 DPRINTF(IEW, "D-Cache became blocked when writing"
914 " [sn:%lli] second packet, will retry later\n",
915 inst->seqNum);
916 }
917 } else {
918
919 // Store the packet for when there's free ports.
920 assert(pendingPkt == NULL);
921 pendingPkt = snd_data_pkt;
922 hasPendingPkt = true;
923 }
924 } else {
925
926 // Not a split store.
927 storePostSend(data_pkt);
928 }
929 }
930 }
931
932 // Not sure this should set it to 0.
933 usedPorts = 0;
934
935 assert(stores >= 0 && storesToWB >= 0);
936}
937
938/*template <class Impl>
939void
940LSQUnit<Impl>::removeMSHR(InstSeqNum seqNum)
941{
942 list<InstSeqNum>::iterator mshr_it = find(mshrSeqNums.begin(),
943 mshrSeqNums.end(),
944 seqNum);
945
946 if (mshr_it != mshrSeqNums.end()) {
947 mshrSeqNums.erase(mshr_it);
948 DPRINTF(LSQUnit, "Removing MSHR. count = %i\n",mshrSeqNums.size());
949 }
950}*/
951
952template <class Impl>
953void
954LSQUnit<Impl>::squash(const InstSeqNum &squashed_num)
955{
956 DPRINTF(LSQUnit, "Squashing until [sn:%lli]!"
957 "(Loads:%i Stores:%i)\n", squashed_num, loads, stores);
958
959 int load_idx = loadTail;
960 decrLdIdx(load_idx);
961
962 while (loads != 0 && loadQueue[load_idx]->seqNum > squashed_num) {
963 DPRINTF(LSQUnit,"Load Instruction PC %s squashed, "
964 "[sn:%lli]\n",
965 loadQueue[load_idx]->pcState(),
966 loadQueue[load_idx]->seqNum);
967
968 if (isStalled() && load_idx == stallingLoadIdx) {
969 stalled = false;
970 stallingStoreIsn = 0;
971 stallingLoadIdx = 0;
972 }
973
974 // Clear the smart pointer to make sure it is decremented.
975 loadQueue[load_idx]->setSquashed();
976 loadQueue[load_idx] = NULL;
977 --loads;
978
979 // Inefficient!
980 loadTail = load_idx;
981
982 decrLdIdx(load_idx);
983 ++lsqSquashedLoads;
984 }
985
986 if (isLoadBlocked) {
987 if (squashed_num < blockedLoadSeqNum) {
988 isLoadBlocked = false;
989 loadBlockedHandled = false;
990 blockedLoadSeqNum = 0;
991 }
992 }
993
994 if (memDepViolator && squashed_num < memDepViolator->seqNum) {
995 memDepViolator = NULL;
996 }
997
998 int store_idx = storeTail;
999 decrStIdx(store_idx);
1000
1001 while (stores != 0 &&
1002 storeQueue[store_idx].inst->seqNum > squashed_num) {
1003 // Instructions marked as can WB are already committed.
1004 if (storeQueue[store_idx].canWB) {
1005 break;
1006 }
1007
1008 DPRINTF(LSQUnit,"Store Instruction PC %s squashed, "
1009 "idx:%i [sn:%lli]\n",
1010 storeQueue[store_idx].inst->pcState(),
1011 store_idx, storeQueue[store_idx].inst->seqNum);
1012
1013 // I don't think this can happen. It should have been cleared
1014 // by the stalling load.
1015 if (isStalled() &&
1016 storeQueue[store_idx].inst->seqNum == stallingStoreIsn) {
1017 panic("Is stalled should have been cleared by stalling load!\n");
1018 stalled = false;
1019 stallingStoreIsn = 0;
1020 }
1021
1022 // Clear the smart pointer to make sure it is decremented.
1023 storeQueue[store_idx].inst->setSquashed();
1024 storeQueue[store_idx].inst = NULL;
1025 storeQueue[store_idx].canWB = 0;
1026
1027 // Must delete request now that it wasn't handed off to
1028 // memory. This is quite ugly. @todo: Figure out the proper
1029 // place to really handle request deletes.
1030 delete storeQueue[store_idx].req;
1031 if (TheISA::HasUnalignedMemAcc && storeQueue[store_idx].isSplit) {
1032 delete storeQueue[store_idx].sreqLow;
1033 delete storeQueue[store_idx].sreqHigh;
1034
1035 storeQueue[store_idx].sreqLow = NULL;
1036 storeQueue[store_idx].sreqHigh = NULL;
1037 }
1038
1039 storeQueue[store_idx].req = NULL;
1040 --stores;
1041
1042 // Inefficient!
1043 storeTail = store_idx;
1044
1045 decrStIdx(store_idx);
1046 ++lsqSquashedStores;
1047 }
1048}
1049
1050template <class Impl>
1051void
1052LSQUnit<Impl>::storePostSend(PacketPtr pkt)
1053{
1054 if (isStalled() &&
1055 storeQueue[storeWBIdx].inst->seqNum == stallingStoreIsn) {
1056 DPRINTF(LSQUnit, "Unstalling, stalling store [sn:%lli] "
1057 "load idx:%i\n",
1058 stallingStoreIsn, stallingLoadIdx);
1059 stalled = false;
1060 stallingStoreIsn = 0;
1061 iewStage->replayMemInst(loadQueue[stallingLoadIdx]);
1062 }
1063
1064 if (!storeQueue[storeWBIdx].inst->isStoreConditional()) {
1065 // The store is basically completed at this time. This
1066 // only works so long as the checker doesn't try to
1067 // verify the value in memory for stores.
1068 storeQueue[storeWBIdx].inst->setCompleted();
1069
1070 if (cpu->checker) {
1071 cpu->checker->verify(storeQueue[storeWBIdx].inst);
1072 }
1073 }
1074
1075 if (needsTSO) {
1076 storeInFlight = true;
1077 }
1078
1079 incrStIdx(storeWBIdx);
1080}
1081
1082template <class Impl>
1083void
1084LSQUnit<Impl>::writeback(DynInstPtr &inst, PacketPtr pkt)
1085{
1086 iewStage->wakeCPU();
1087
1088 // Squashed instructions do not need to complete their access.
1089 if (inst->isSquashed()) {
1090 iewStage->decrWb(inst->seqNum);
1091 assert(!inst->isStore());
1092 ++lsqIgnoredResponses;
1093 return;
1094 }
1095
1096 if (!inst->isExecuted()) {
1097 inst->setExecuted();
1098
1099 // Complete access to copy data to proper place.
1100 inst->completeAcc(pkt);
1101 }
1102
1103 // Need to insert instruction into queue to commit
1104 iewStage->instToCommit(inst);
1105
1106 iewStage->activityThisCycle();
1107
1108 // see if this load changed the PC
1109 iewStage->checkMisprediction(inst);
1110}
1111
1112template <class Impl>
1113void
1114LSQUnit<Impl>::completeStore(int store_idx)
1115{
1116 assert(storeQueue[store_idx].inst);
1117 storeQueue[store_idx].completed = true;
1118 --storesToWB;
1119 // A bit conservative because a store completion may not free up entries,
1120 // but hopefully avoids two store completions in one cycle from making
1121 // the CPU tick twice.
1122 cpu->wakeCPU();
1123 cpu->activityThisCycle();
1124
1125 if (store_idx == storeHead) {
1126 do {
1127 incrStIdx(storeHead);
1128
1129 --stores;
1130 } while (storeQueue[storeHead].completed &&
1131 storeHead != storeTail);
1132
1133 iewStage->updateLSQNextCycle = true;
1134 }
1135
1136 DPRINTF(LSQUnit, "Completing store [sn:%lli], idx:%i, store head "
1137 "idx:%i\n",
1138 storeQueue[store_idx].inst->seqNum, store_idx, storeHead);
1139
| 55#include "mem/packet.hh"
56#include "mem/request.hh"
57
58template<class Impl>
59LSQUnit<Impl>::WritebackEvent::WritebackEvent(DynInstPtr &_inst, PacketPtr _pkt,
60 LSQUnit *lsq_ptr)
61 : Event(Default_Pri, AutoDelete),
62 inst(_inst), pkt(_pkt), lsqPtr(lsq_ptr)
63{
64}
65
66template<class Impl>
67void
68LSQUnit<Impl>::WritebackEvent::process()
69{
70 assert(!lsqPtr->cpu->switchedOut());
71
72 lsqPtr->writeback(inst, pkt);
73
74 if (pkt->senderState)
75 delete pkt->senderState;
76
77 delete pkt->req;
78 delete pkt;
79}
80
81template<class Impl>
82const char *
83LSQUnit<Impl>::WritebackEvent::description() const
84{
85 return "Store writeback";
86}
87
88template<class Impl>
89void
90LSQUnit<Impl>::completeDataAccess(PacketPtr pkt)
91{
92 LSQSenderState *state = dynamic_cast<LSQSenderState *>(pkt->senderState);
93 DynInstPtr inst = state->inst;
94 DPRINTF(IEW, "Writeback event [sn:%lli].\n", inst->seqNum);
95 DPRINTF(Activity, "Activity: Writeback event [sn:%lli].\n", inst->seqNum);
96
97 //iewStage->ldstQueue.removeMSHR(inst->threadNumber,inst->seqNum);
98
99 // If this is a split access, wait until all packets are received.
100 if (TheISA::HasUnalignedMemAcc && !state->complete()) {
101 delete pkt->req;
102 delete pkt;
103 return;
104 }
105
106 assert(!cpu->switchedOut());
107 if (inst->isSquashed()) {
108 iewStage->decrWb(inst->seqNum);
109 } else {
110 if (!state->noWB) {
111 if (!TheISA::HasUnalignedMemAcc || !state->isSplit ||
112 !state->isLoad) {
113 writeback(inst, pkt);
114 } else {
115 writeback(inst, state->mainPkt);
116 }
117 }
118
119 if (inst->isStore()) {
120 completeStore(state->idx);
121 }
122 }
123
124 if (TheISA::HasUnalignedMemAcc && state->isSplit && state->isLoad) {
125 delete state->mainPkt->req;
126 delete state->mainPkt;
127 }
128 delete state;
129 delete pkt->req;
130 delete pkt;
131}
132
133template <class Impl>
134LSQUnit<Impl>::LSQUnit()
135 : loads(0), stores(0), storesToWB(0), cacheBlockMask(0), stalled(false),
136 isStoreBlocked(false), isLoadBlocked(false),
137 loadBlockedHandled(false), storeInFlight(false), hasPendingPkt(false)
138{
139}
140
141template<class Impl>
142void
143LSQUnit<Impl>::init(O3CPU *cpu_ptr, IEW *iew_ptr, DerivO3CPUParams *params,
144 LSQ *lsq_ptr, unsigned maxLQEntries, unsigned maxSQEntries,
145 unsigned id)
146{
147 cpu = cpu_ptr;
148 iewStage = iew_ptr;
149
150 DPRINTF(LSQUnit, "Creating LSQUnit%i object.\n",id);
151
152 lsq = lsq_ptr;
153
154 lsqID = id;
155
156 // Add 1 for the sentinel entry (they are circular queues).
157 LQEntries = maxLQEntries + 1;
158 SQEntries = maxSQEntries + 1;
159
160 loadQueue.resize(LQEntries);
161 storeQueue.resize(SQEntries);
162
163 depCheckShift = params->LSQDepCheckShift;
164 checkLoads = params->LSQCheckLoads;
165 cachePorts = params->cachePorts;
166 needsTSO = params->needsTSO;
167
168 resetState();
169}
170
171
172template<class Impl>
173void
174LSQUnit<Impl>::resetState()
175{
176 loads = stores = storesToWB = 0;
177
178 loadHead = loadTail = 0;
179
180 storeHead = storeWBIdx = storeTail = 0;
181
182 usedPorts = 0;
183
184 retryPkt = NULL;
185 memDepViolator = NULL;
186
187 blockedLoadSeqNum = 0;
188
189 stalled = false;
190 isLoadBlocked = false;
191 loadBlockedHandled = false;
192
193 cacheBlockMask = 0;
194}
195
196template<class Impl>
197std::string
198LSQUnit<Impl>::name() const
199{
200 if (Impl::MaxThreads == 1) {
201 return iewStage->name() + ".lsq";
202 } else {
203 return iewStage->name() + ".lsq.thread" + to_string(lsqID);
204 }
205}
206
207template<class Impl>
208void
209LSQUnit<Impl>::regStats()
210{
211 lsqForwLoads
212 .name(name() + ".forwLoads")
213 .desc("Number of loads that had data forwarded from stores");
214
215 invAddrLoads
216 .name(name() + ".invAddrLoads")
217 .desc("Number of loads ignored due to an invalid address");
218
219 lsqSquashedLoads
220 .name(name() + ".squashedLoads")
221 .desc("Number of loads squashed");
222
223 lsqIgnoredResponses
224 .name(name() + ".ignoredResponses")
225 .desc("Number of memory responses ignored because the instruction is squashed");
226
227 lsqMemOrderViolation
228 .name(name() + ".memOrderViolation")
229 .desc("Number of memory ordering violations");
230
231 lsqSquashedStores
232 .name(name() + ".squashedStores")
233 .desc("Number of stores squashed");
234
235 invAddrSwpfs
236 .name(name() + ".invAddrSwpfs")
237 .desc("Number of software prefetches ignored due to an invalid address");
238
239 lsqBlockedLoads
240 .name(name() + ".blockedLoads")
241 .desc("Number of blocked loads due to partial load-store forwarding");
242
243 lsqRescheduledLoads
244 .name(name() + ".rescheduledLoads")
245 .desc("Number of loads that were rescheduled");
246
247 lsqCacheBlocked
248 .name(name() + ".cacheBlocked")
249 .desc("Number of times an access to memory failed due to the cache being blocked");
250}
251
252template<class Impl>
253void
254LSQUnit<Impl>::setDcachePort(MasterPort *dcache_port)
255{
256 dcachePort = dcache_port;
257}
258
259template<class Impl>
260void
261LSQUnit<Impl>::clearLQ()
262{
263 loadQueue.clear();
264}
265
266template<class Impl>
267void
268LSQUnit<Impl>::clearSQ()
269{
270 storeQueue.clear();
271}
272
273template<class Impl>
274void
275LSQUnit<Impl>::drainSanityCheck() const
276{
277 for (int i = 0; i < loadQueue.size(); ++i)
278 assert(!loadQueue[i]);
279
280 assert(storesToWB == 0);
281 assert(!retryPkt);
282}
283
284template<class Impl>
285void
286LSQUnit<Impl>::takeOverFrom()
287{
288 resetState();
289}
290
291template<class Impl>
292void
293LSQUnit<Impl>::resizeLQ(unsigned size)
294{
295 unsigned size_plus_sentinel = size + 1;
296 assert(size_plus_sentinel >= LQEntries);
297
298 if (size_plus_sentinel > LQEntries) {
299 while (size_plus_sentinel > loadQueue.size()) {
300 DynInstPtr dummy;
301 loadQueue.push_back(dummy);
302 LQEntries++;
303 }
304 } else {
305 LQEntries = size_plus_sentinel;
306 }
307
308}
309
310template<class Impl>
311void
312LSQUnit<Impl>::resizeSQ(unsigned size)
313{
314 unsigned size_plus_sentinel = size + 1;
315 if (size_plus_sentinel > SQEntries) {
316 while (size_plus_sentinel > storeQueue.size()) {
317 SQEntry dummy;
318 storeQueue.push_back(dummy);
319 SQEntries++;
320 }
321 } else {
322 SQEntries = size_plus_sentinel;
323 }
324}
325
326template <class Impl>
327void
328LSQUnit<Impl>::insert(DynInstPtr &inst)
329{
330 assert(inst->isMemRef());
331
332 assert(inst->isLoad() || inst->isStore());
333
334 if (inst->isLoad()) {
335 insertLoad(inst);
336 } else {
337 insertStore(inst);
338 }
339
340 inst->setInLSQ();
341}
342
343template <class Impl>
344void
345LSQUnit<Impl>::insertLoad(DynInstPtr &load_inst)
346{
347 assert((loadTail + 1) % LQEntries != loadHead);
348 assert(loads < LQEntries);
349
350 DPRINTF(LSQUnit, "Inserting load PC %s, idx:%i [sn:%lli]\n",
351 load_inst->pcState(), loadTail, load_inst->seqNum);
352
353 load_inst->lqIdx = loadTail;
354
355 if (stores == 0) {
356 load_inst->sqIdx = -1;
357 } else {
358 load_inst->sqIdx = storeTail;
359 }
360
361 loadQueue[loadTail] = load_inst;
362
363 incrLdIdx(loadTail);
364
365 ++loads;
366}
367
368template <class Impl>
369void
370LSQUnit<Impl>::insertStore(DynInstPtr &store_inst)
371{
372 // Make sure it is not full before inserting an instruction.
373 assert((storeTail + 1) % SQEntries != storeHead);
374 assert(stores < SQEntries);
375
376 DPRINTF(LSQUnit, "Inserting store PC %s, idx:%i [sn:%lli]\n",
377 store_inst->pcState(), storeTail, store_inst->seqNum);
378
379 store_inst->sqIdx = storeTail;
380 store_inst->lqIdx = loadTail;
381
382 storeQueue[storeTail] = SQEntry(store_inst);
383
384 incrStIdx(storeTail);
385
386 ++stores;
387}
388
389template <class Impl>
390typename Impl::DynInstPtr
391LSQUnit<Impl>::getMemDepViolator()
392{
393 DynInstPtr temp = memDepViolator;
394
395 memDepViolator = NULL;
396
397 return temp;
398}
399
400template <class Impl>
401unsigned
402LSQUnit<Impl>::numFreeEntries()
403{
404 unsigned free_lq_entries = LQEntries - loads;
405 unsigned free_sq_entries = SQEntries - stores;
406
407 // Both the LQ and SQ entries have an extra dummy entry to differentiate
408 // empty/full conditions. Subtract 1 from the free entries.
409 if (free_lq_entries < free_sq_entries) {
410 return free_lq_entries - 1;
411 } else {
412 return free_sq_entries - 1;
413 }
414}
415
416template <class Impl>
417void
418LSQUnit<Impl>::checkSnoop(PacketPtr pkt)
419{
420 int load_idx = loadHead;
421
422 if (!cacheBlockMask) {
423 assert(dcachePort);
424 Addr bs = dcachePort->peerBlockSize();
425
426 // Make sure we actually got a size
427 assert(bs != 0);
428
429 cacheBlockMask = ~(bs - 1);
430 }
431
432 // Unlock the cpu-local monitor when the CPU sees a snoop to a locked
433 // address. The CPU can speculatively execute a LL operation after a pending
434 // SC operation in the pipeline and that can make the cache monitor the CPU
435 // is connected to valid while it really shouldn't be.
436 for (int x = 0; x < cpu->numActiveThreads(); x++) {
437 ThreadContext *tc = cpu->getContext(x);
438 bool no_squash = cpu->thread[x]->noSquashFromTC;
439 cpu->thread[x]->noSquashFromTC = true;
440 TheISA::handleLockedSnoop(tc, pkt, cacheBlockMask);
441 cpu->thread[x]->noSquashFromTC = no_squash;
442 }
443
444 // If this is the only load in the LSQ we don't care
445 if (load_idx == loadTail)
446 return;
447 incrLdIdx(load_idx);
448
449 DPRINTF(LSQUnit, "Got snoop for address %#x\n", pkt->getAddr());
450 Addr invalidate_addr = pkt->getAddr() & cacheBlockMask;
451 while (load_idx != loadTail) {
452 DynInstPtr ld_inst = loadQueue[load_idx];
453
454 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) {
455 incrLdIdx(load_idx);
456 continue;
457 }
458
459 Addr load_addr = ld_inst->physEffAddr & cacheBlockMask;
460 DPRINTF(LSQUnit, "-- inst [sn:%lli] load_addr: %#x to pktAddr:%#x\n",
461 ld_inst->seqNum, load_addr, invalidate_addr);
462
463 if (load_addr == invalidate_addr) {
464 if (ld_inst->possibleLoadViolation()) {
465 DPRINTF(LSQUnit, "Conflicting load at addr %#x [sn:%lli]\n",
466 ld_inst->physEffAddr, pkt->getAddr(), ld_inst->seqNum);
467
468 // Mark the load for re-execution
469 ld_inst->fault = new ReExec;
470 } else {
471 // If a older load checks this and it's true
472 // then we might have missed the snoop
473 // in which case we need to invalidate to be sure
474 ld_inst->hitExternalSnoop(true);
475 }
476 }
477 incrLdIdx(load_idx);
478 }
479 return;
480}
481
482template <class Impl>
483Fault
484LSQUnit<Impl>::checkViolations(int load_idx, DynInstPtr &inst)
485{
486 Addr inst_eff_addr1 = inst->effAddr >> depCheckShift;
487 Addr inst_eff_addr2 = (inst->effAddr + inst->effSize - 1) >> depCheckShift;
488
489 /** @todo in theory you only need to check an instruction that has executed
490 * however, there isn't a good way in the pipeline at the moment to check
491 * all instructions that will execute before the store writes back. Thus,
492 * like the implementation that came before it, we're overly conservative.
493 */
494 while (load_idx != loadTail) {
495 DynInstPtr ld_inst = loadQueue[load_idx];
496 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) {
497 incrLdIdx(load_idx);
498 continue;
499 }
500
501 Addr ld_eff_addr1 = ld_inst->effAddr >> depCheckShift;
502 Addr ld_eff_addr2 =
503 (ld_inst->effAddr + ld_inst->effSize - 1) >> depCheckShift;
504
505 if (inst_eff_addr2 >= ld_eff_addr1 && inst_eff_addr1 <= ld_eff_addr2) {
506 if (inst->isLoad()) {
507 // If this load is to the same block as an external snoop
508 // invalidate that we've observed then the load needs to be
509 // squashed as it could have newer data
510 if (ld_inst->hitExternalSnoop()) {
511 if (!memDepViolator ||
512 ld_inst->seqNum < memDepViolator->seqNum) {
513 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] "
514 "and [sn:%lli] at address %#x\n",
515 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
516 memDepViolator = ld_inst;
517
518 ++lsqMemOrderViolation;
519
520 return new GenericISA::M5PanicFault(
521 "Detected fault with inst [sn:%lli] and "
522 "[sn:%lli] at address %#x\n",
523 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
524 }
525 }
526
527 // Otherwise, mark the load has a possible load violation
528 // and if we see a snoop before it's commited, we need to squash
529 ld_inst->possibleLoadViolation(true);
530 DPRINTF(LSQUnit, "Found possible load violaiton at addr: %#x"
531 " between instructions [sn:%lli] and [sn:%lli]\n",
532 inst_eff_addr1, inst->seqNum, ld_inst->seqNum);
533 } else {
534 // A load/store incorrectly passed this store.
535 // Check if we already have a violator, or if it's newer
536 // squash and refetch.
537 if (memDepViolator && ld_inst->seqNum > memDepViolator->seqNum)
538 break;
539
540 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] and "
541 "[sn:%lli] at address %#x\n",
542 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
543 memDepViolator = ld_inst;
544
545 ++lsqMemOrderViolation;
546
547 return new GenericISA::M5PanicFault("Detected fault with "
548 "inst [sn:%lli] and [sn:%lli] at address %#x\n",
549 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
550 }
551 }
552
553 incrLdIdx(load_idx);
554 }
555 return NoFault;
556}
557
558
559
560
561template <class Impl>
562Fault
563LSQUnit<Impl>::executeLoad(DynInstPtr &inst)
564{
565 using namespace TheISA;
566 // Execute a specific load.
567 Fault load_fault = NoFault;
568
569 DPRINTF(LSQUnit, "Executing load PC %s, [sn:%lli]\n",
570 inst->pcState(), inst->seqNum);
571
572 assert(!inst->isSquashed());
573
574 load_fault = inst->initiateAcc();
575
576 if (inst->isTranslationDelayed() &&
577 load_fault == NoFault)
578 return load_fault;
579
580 // If the instruction faulted or predicated false, then we need to send it
581 // along to commit without the instruction completing.
582 if (load_fault != NoFault || inst->readPredicate() == false) {
583 // Send this instruction to commit, also make sure iew stage
584 // realizes there is activity.
585 // Mark it as executed unless it is an uncached load that
586 // needs to hit the head of commit.
587 if (inst->readPredicate() == false)
588 inst->forwardOldRegs();
589 DPRINTF(LSQUnit, "Load [sn:%lli] not executed from %s\n",
590 inst->seqNum,
591 (load_fault != NoFault ? "fault" : "predication"));
592 if (!(inst->hasRequest() && inst->uncacheable()) ||
593 inst->isAtCommit()) {
594 inst->setExecuted();
595 }
596 iewStage->instToCommit(inst);
597 iewStage->activityThisCycle();
598 } else if (!loadBlocked()) {
599 assert(inst->effAddrValid());
600 int load_idx = inst->lqIdx;
601 incrLdIdx(load_idx);
602
603 if (checkLoads)
604 return checkViolations(load_idx, inst);
605 }
606
607 return load_fault;
608}
609
610template <class Impl>
611Fault
612LSQUnit<Impl>::executeStore(DynInstPtr &store_inst)
613{
614 using namespace TheISA;
615 // Make sure that a store exists.
616 assert(stores != 0);
617
618 int store_idx = store_inst->sqIdx;
619
620 DPRINTF(LSQUnit, "Executing store PC %s [sn:%lli]\n",
621 store_inst->pcState(), store_inst->seqNum);
622
623 assert(!store_inst->isSquashed());
624
625 // Check the recently completed loads to see if any match this store's
626 // address. If so, then we have a memory ordering violation.
627 int load_idx = store_inst->lqIdx;
628
629 Fault store_fault = store_inst->initiateAcc();
630
631 if (store_inst->isTranslationDelayed() &&
632 store_fault == NoFault)
633 return store_fault;
634
635 if (store_inst->readPredicate() == false)
636 store_inst->forwardOldRegs();
637
638 if (storeQueue[store_idx].size == 0) {
639 DPRINTF(LSQUnit,"Fault on Store PC %s, [sn:%lli], Size = 0\n",
640 store_inst->pcState(), store_inst->seqNum);
641
642 return store_fault;
643 } else if (store_inst->readPredicate() == false) {
644 DPRINTF(LSQUnit, "Store [sn:%lli] not executed from predication\n",
645 store_inst->seqNum);
646 return store_fault;
647 }
648
649 assert(store_fault == NoFault);
650
651 if (store_inst->isStoreConditional()) {
652 // Store conditionals need to set themselves as able to
653 // writeback if we haven't had a fault by here.
654 storeQueue[store_idx].canWB = true;
655
656 ++storesToWB;
657 }
658
659 return checkViolations(load_idx, store_inst);
660
661}
662
663template <class Impl>
664void
665LSQUnit<Impl>::commitLoad()
666{
667 assert(loadQueue[loadHead]);
668
669 DPRINTF(LSQUnit, "Committing head load instruction, PC %s\n",
670 loadQueue[loadHead]->pcState());
671
672 loadQueue[loadHead] = NULL;
673
674 incrLdIdx(loadHead);
675
676 --loads;
677}
678
679template <class Impl>
680void
681LSQUnit<Impl>::commitLoads(InstSeqNum &youngest_inst)
682{
683 assert(loads == 0 || loadQueue[loadHead]);
684
685 while (loads != 0 && loadQueue[loadHead]->seqNum <= youngest_inst) {
686 commitLoad();
687 }
688}
689
690template <class Impl>
691void
692LSQUnit<Impl>::commitStores(InstSeqNum &youngest_inst)
693{
694 assert(stores == 0 || storeQueue[storeHead].inst);
695
696 int store_idx = storeHead;
697
698 while (store_idx != storeTail) {
699 assert(storeQueue[store_idx].inst);
700 // Mark any stores that are now committed and have not yet
701 // been marked as able to write back.
702 if (!storeQueue[store_idx].canWB) {
703 if (storeQueue[store_idx].inst->seqNum > youngest_inst) {
704 break;
705 }
706 DPRINTF(LSQUnit, "Marking store as able to write back, PC "
707 "%s [sn:%lli]\n",
708 storeQueue[store_idx].inst->pcState(),
709 storeQueue[store_idx].inst->seqNum);
710
711 storeQueue[store_idx].canWB = true;
712
713 ++storesToWB;
714 }
715
716 incrStIdx(store_idx);
717 }
718}
719
720template <class Impl>
721void
722LSQUnit<Impl>::writebackPendingStore()
723{
724 if (hasPendingPkt) {
725 assert(pendingPkt != NULL);
726
727 // If the cache is blocked, this will store the packet for retry.
728 if (sendStore(pendingPkt)) {
729 storePostSend(pendingPkt);
730 }
731 pendingPkt = NULL;
732 hasPendingPkt = false;
733 }
734}
735
736template <class Impl>
737void
738LSQUnit<Impl>::writebackStores()
739{
740 // First writeback the second packet from any split store that didn't
741 // complete last cycle because there weren't enough cache ports available.
742 if (TheISA::HasUnalignedMemAcc) {
743 writebackPendingStore();
744 }
745
746 while (storesToWB > 0 &&
747 storeWBIdx != storeTail &&
748 storeQueue[storeWBIdx].inst &&
749 storeQueue[storeWBIdx].canWB &&
750 ((!needsTSO) || (!storeInFlight)) &&
751 usedPorts < cachePorts) {
752
753 if (isStoreBlocked || lsq->cacheBlocked()) {
754 DPRINTF(LSQUnit, "Unable to write back any more stores, cache"
755 " is blocked!\n");
756 break;
757 }
758
759 // Store didn't write any data so no need to write it back to
760 // memory.
761 if (storeQueue[storeWBIdx].size == 0) {
762 completeStore(storeWBIdx);
763
764 incrStIdx(storeWBIdx);
765
766 continue;
767 }
768
769 ++usedPorts;
770
771 if (storeQueue[storeWBIdx].inst->isDataPrefetch()) {
772 incrStIdx(storeWBIdx);
773
774 continue;
775 }
776
777 assert(storeQueue[storeWBIdx].req);
778 assert(!storeQueue[storeWBIdx].committed);
779
780 if (TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit) {
781 assert(storeQueue[storeWBIdx].sreqLow);
782 assert(storeQueue[storeWBIdx].sreqHigh);
783 }
784
785 DynInstPtr inst = storeQueue[storeWBIdx].inst;
786
787 Request *req = storeQueue[storeWBIdx].req;
788 RequestPtr sreqLow = storeQueue[storeWBIdx].sreqLow;
789 RequestPtr sreqHigh = storeQueue[storeWBIdx].sreqHigh;
790
791 storeQueue[storeWBIdx].committed = true;
792
793 assert(!inst->memData);
794 inst->memData = new uint8_t[64];
795
796 memcpy(inst->memData, storeQueue[storeWBIdx].data, req->getSize());
797
798 MemCmd command =
799 req->isSwap() ? MemCmd::SwapReq :
800 (req->isLLSC() ? MemCmd::StoreCondReq : MemCmd::WriteReq);
801 PacketPtr data_pkt;
802 PacketPtr snd_data_pkt = NULL;
803
804 LSQSenderState *state = new LSQSenderState;
805 state->isLoad = false;
806 state->idx = storeWBIdx;
807 state->inst = inst;
808
809 if (!TheISA::HasUnalignedMemAcc || !storeQueue[storeWBIdx].isSplit) {
810
811 // Build a single data packet if the store isn't split.
812 data_pkt = new Packet(req, command);
813 data_pkt->dataStatic(inst->memData);
814 data_pkt->senderState = state;
815 } else {
816 // Create two packets if the store is split in two.
817 data_pkt = new Packet(sreqLow, command);
818 snd_data_pkt = new Packet(sreqHigh, command);
819
820 data_pkt->dataStatic(inst->memData);
821 snd_data_pkt->dataStatic(inst->memData + sreqLow->getSize());
822
823 data_pkt->senderState = state;
824 snd_data_pkt->senderState = state;
825
826 state->isSplit = true;
827 state->outstanding = 2;
828
829 // Can delete the main request now.
830 delete req;
831 req = sreqLow;
832 }
833
834 DPRINTF(LSQUnit, "D-Cache: Writing back store idx:%i PC:%s "
835 "to Addr:%#x, data:%#x [sn:%lli]\n",
836 storeWBIdx, inst->pcState(),
837 req->getPaddr(), (int)*(inst->memData),
838 inst->seqNum);
839
840 // @todo: Remove this SC hack once the memory system handles it.
841 if (inst->isStoreConditional()) {
842 assert(!storeQueue[storeWBIdx].isSplit);
843 // Disable recording the result temporarily. Writing to
844 // misc regs normally updates the result, but this is not
845 // the desired behavior when handling store conditionals.
846 inst->recordResult(false);
847 bool success = TheISA::handleLockedWrite(inst.get(), req);
848 inst->recordResult(true);
849
850 if (!success) {
851 // Instantly complete this store.
852 DPRINTF(LSQUnit, "Store conditional [sn:%lli] failed. "
853 "Instantly completing it.\n",
854 inst->seqNum);
855 WritebackEvent *wb = new WritebackEvent(inst, data_pkt, this);
856 cpu->schedule(wb, curTick() + 1);
857 if (cpu->checker) {
858 // Make sure to set the LLSC data for verification
859 // if checker is loaded
860 inst->reqToVerify->setExtraData(0);
861 inst->completeAcc(data_pkt);
862 }
863 completeStore(storeWBIdx);
864 incrStIdx(storeWBIdx);
865 continue;
866 }
867 } else {
868 // Non-store conditionals do not need a writeback.
869 state->noWB = true;
870 }
871
872 bool split =
873 TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit;
874
875 ThreadContext *thread = cpu->tcBase(lsqID);
876
877 if (req->isMmappedIpr()) {
878 assert(!inst->isStoreConditional());
879 TheISA::handleIprWrite(thread, data_pkt);
880 delete data_pkt;
881 if (split) {
882 assert(snd_data_pkt->req->isMmappedIpr());
883 TheISA::handleIprWrite(thread, snd_data_pkt);
884 delete snd_data_pkt;
885 delete sreqLow;
886 delete sreqHigh;
887 }
888 delete state;
889 delete req;
890 completeStore(storeWBIdx);
891 incrStIdx(storeWBIdx);
892 } else if (!sendStore(data_pkt)) {
893 DPRINTF(IEW, "D-Cache became blocked when writing [sn:%lli], will"
894 "retry later\n",
895 inst->seqNum);
896
897 // Need to store the second packet, if split.
898 if (split) {
899 state->pktToSend = true;
900 state->pendingPacket = snd_data_pkt;
901 }
902 } else {
903
904 // If split, try to send the second packet too
905 if (split) {
906 assert(snd_data_pkt);
907
908 // Ensure there are enough ports to use.
909 if (usedPorts < cachePorts) {
910 ++usedPorts;
911 if (sendStore(snd_data_pkt)) {
912 storePostSend(snd_data_pkt);
913 } else {
914 DPRINTF(IEW, "D-Cache became blocked when writing"
915 " [sn:%lli] second packet, will retry later\n",
916 inst->seqNum);
917 }
918 } else {
919
920 // Store the packet for when there's free ports.
921 assert(pendingPkt == NULL);
922 pendingPkt = snd_data_pkt;
923 hasPendingPkt = true;
924 }
925 } else {
926
927 // Not a split store.
928 storePostSend(data_pkt);
929 }
930 }
931 }
932
933 // Not sure this should set it to 0.
934 usedPorts = 0;
935
936 assert(stores >= 0 && storesToWB >= 0);
937}
938
939/*template <class Impl>
940void
941LSQUnit<Impl>::removeMSHR(InstSeqNum seqNum)
942{
943 list<InstSeqNum>::iterator mshr_it = find(mshrSeqNums.begin(),
944 mshrSeqNums.end(),
945 seqNum);
946
947 if (mshr_it != mshrSeqNums.end()) {
948 mshrSeqNums.erase(mshr_it);
949 DPRINTF(LSQUnit, "Removing MSHR. count = %i\n",mshrSeqNums.size());
950 }
951}*/
952
953template <class Impl>
954void
955LSQUnit<Impl>::squash(const InstSeqNum &squashed_num)
956{
957 DPRINTF(LSQUnit, "Squashing until [sn:%lli]!"
958 "(Loads:%i Stores:%i)\n", squashed_num, loads, stores);
959
960 int load_idx = loadTail;
961 decrLdIdx(load_idx);
962
963 while (loads != 0 && loadQueue[load_idx]->seqNum > squashed_num) {
964 DPRINTF(LSQUnit,"Load Instruction PC %s squashed, "
965 "[sn:%lli]\n",
966 loadQueue[load_idx]->pcState(),
967 loadQueue[load_idx]->seqNum);
968
969 if (isStalled() && load_idx == stallingLoadIdx) {
970 stalled = false;
971 stallingStoreIsn = 0;
972 stallingLoadIdx = 0;
973 }
974
975 // Clear the smart pointer to make sure it is decremented.
976 loadQueue[load_idx]->setSquashed();
977 loadQueue[load_idx] = NULL;
978 --loads;
979
980 // Inefficient!
981 loadTail = load_idx;
982
983 decrLdIdx(load_idx);
984 ++lsqSquashedLoads;
985 }
986
987 if (isLoadBlocked) {
988 if (squashed_num < blockedLoadSeqNum) {
989 isLoadBlocked = false;
990 loadBlockedHandled = false;
991 blockedLoadSeqNum = 0;
992 }
993 }
994
995 if (memDepViolator && squashed_num < memDepViolator->seqNum) {
996 memDepViolator = NULL;
997 }
998
999 int store_idx = storeTail;
1000 decrStIdx(store_idx);
1001
1002 while (stores != 0 &&
1003 storeQueue[store_idx].inst->seqNum > squashed_num) {
1004 // Instructions marked as can WB are already committed.
1005 if (storeQueue[store_idx].canWB) {
1006 break;
1007 }
1008
1009 DPRINTF(LSQUnit,"Store Instruction PC %s squashed, "
1010 "idx:%i [sn:%lli]\n",
1011 storeQueue[store_idx].inst->pcState(),
1012 store_idx, storeQueue[store_idx].inst->seqNum);
1013
1014 // I don't think this can happen. It should have been cleared
1015 // by the stalling load.
1016 if (isStalled() &&
1017 storeQueue[store_idx].inst->seqNum == stallingStoreIsn) {
1018 panic("Is stalled should have been cleared by stalling load!\n");
1019 stalled = false;
1020 stallingStoreIsn = 0;
1021 }
1022
1023 // Clear the smart pointer to make sure it is decremented.
1024 storeQueue[store_idx].inst->setSquashed();
1025 storeQueue[store_idx].inst = NULL;
1026 storeQueue[store_idx].canWB = 0;
1027
1028 // Must delete request now that it wasn't handed off to
1029 // memory. This is quite ugly. @todo: Figure out the proper
1030 // place to really handle request deletes.
1031 delete storeQueue[store_idx].req;
1032 if (TheISA::HasUnalignedMemAcc && storeQueue[store_idx].isSplit) {
1033 delete storeQueue[store_idx].sreqLow;
1034 delete storeQueue[store_idx].sreqHigh;
1035
1036 storeQueue[store_idx].sreqLow = NULL;
1037 storeQueue[store_idx].sreqHigh = NULL;
1038 }
1039
1040 storeQueue[store_idx].req = NULL;
1041 --stores;
1042
1043 // Inefficient!
1044 storeTail = store_idx;
1045
1046 decrStIdx(store_idx);
1047 ++lsqSquashedStores;
1048 }
1049}
1050
1051template <class Impl>
1052void
1053LSQUnit<Impl>::storePostSend(PacketPtr pkt)
1054{
1055 if (isStalled() &&
1056 storeQueue[storeWBIdx].inst->seqNum == stallingStoreIsn) {
1057 DPRINTF(LSQUnit, "Unstalling, stalling store [sn:%lli] "
1058 "load idx:%i\n",
1059 stallingStoreIsn, stallingLoadIdx);
1060 stalled = false;
1061 stallingStoreIsn = 0;
1062 iewStage->replayMemInst(loadQueue[stallingLoadIdx]);
1063 }
1064
1065 if (!storeQueue[storeWBIdx].inst->isStoreConditional()) {
1066 // The store is basically completed at this time. This
1067 // only works so long as the checker doesn't try to
1068 // verify the value in memory for stores.
1069 storeQueue[storeWBIdx].inst->setCompleted();
1070
1071 if (cpu->checker) {
1072 cpu->checker->verify(storeQueue[storeWBIdx].inst);
1073 }
1074 }
1075
1076 if (needsTSO) {
1077 storeInFlight = true;
1078 }
1079
1080 incrStIdx(storeWBIdx);
1081}
1082
1083template <class Impl>
1084void
1085LSQUnit<Impl>::writeback(DynInstPtr &inst, PacketPtr pkt)
1086{
1087 iewStage->wakeCPU();
1088
1089 // Squashed instructions do not need to complete their access.
1090 if (inst->isSquashed()) {
1091 iewStage->decrWb(inst->seqNum);
1092 assert(!inst->isStore());
1093 ++lsqIgnoredResponses;
1094 return;
1095 }
1096
1097 if (!inst->isExecuted()) {
1098 inst->setExecuted();
1099
1100 // Complete access to copy data to proper place.
1101 inst->completeAcc(pkt);
1102 }
1103
1104 // Need to insert instruction into queue to commit
1105 iewStage->instToCommit(inst);
1106
1107 iewStage->activityThisCycle();
1108
1109 // see if this load changed the PC
1110 iewStage->checkMisprediction(inst);
1111}
1112
1113template <class Impl>
1114void
1115LSQUnit<Impl>::completeStore(int store_idx)
1116{
1117 assert(storeQueue[store_idx].inst);
1118 storeQueue[store_idx].completed = true;
1119 --storesToWB;
1120 // A bit conservative because a store completion may not free up entries,
1121 // but hopefully avoids two store completions in one cycle from making
1122 // the CPU tick twice.
1123 cpu->wakeCPU();
1124 cpu->activityThisCycle();
1125
1126 if (store_idx == storeHead) {
1127 do {
1128 incrStIdx(storeHead);
1129
1130 --stores;
1131 } while (storeQueue[storeHead].completed &&
1132 storeHead != storeTail);
1133
1134 iewStage->updateLSQNextCycle = true;
1135 }
1136
1137 DPRINTF(LSQUnit, "Completing store [sn:%lli], idx:%i, store head "
1138 "idx:%i\n",
1139 storeQueue[store_idx].inst->seqNum, store_idx, storeHead);
1140
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