1/*
2 * Copyright (c) 2010-2012 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) 2004-2005 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: Kevin Lim
41 * Korey Sewell
42 */
43
44#include "arch/generic/debugfaults.hh"
45#include "arch/locked_mem.hh"
46#include "base/str.hh"
47#include "config/the_isa.hh"
48#include "cpu/checker/cpu.hh"
49#include "cpu/o3/lsq.hh"
50#include "cpu/o3/lsq_unit.hh"
51#include "debug/Activity.hh"
52#include "debug/IEW.hh"
53#include "debug/LSQUnit.hh"
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 if (!lsqPtr->isSwitchedOut()) {
70 lsqPtr->writeback(inst, pkt);
71 }
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 if (isSwitchedOut() || inst->isSquashed()) {
106 iewStage->decrWb(inst->seqNum);
107 } else {
108 if (!state->noWB) {
109 if (!TheISA::HasUnalignedMemAcc || !state->isSplit ||
110 !state->isLoad) {
111 writeback(inst, pkt);
112 } else {
113 writeback(inst, state->mainPkt);
114 }
115 }
116
117 if (inst->isStore()) {
118 completeStore(state->idx);
119 }
120 }
121
122 if (TheISA::HasUnalignedMemAcc && state->isSplit && state->isLoad) {
123 delete state->mainPkt->req;
124 delete state->mainPkt;
125 }
126 delete state;
127 delete pkt->req;
128 delete pkt;
129}
130
131template <class Impl>
132LSQUnit<Impl>::LSQUnit()
133 : loads(0), stores(0), storesToWB(0), cacheBlockMask(0), stalled(false),
134 isStoreBlocked(false), isLoadBlocked(false),
135 loadBlockedHandled(false), storeInFlight(false), hasPendingPkt(false)
136{
137}
138
139template<class Impl>
140void
141LSQUnit<Impl>::init(O3CPU *cpu_ptr, IEW *iew_ptr, DerivO3CPUParams *params,
142 LSQ *lsq_ptr, unsigned maxLQEntries, unsigned maxSQEntries,
143 unsigned id)
144{
145 cpu = cpu_ptr;
146 iewStage = iew_ptr;
147
148 DPRINTF(LSQUnit, "Creating LSQUnit%i object.\n",id);
149
150 switchedOut = false;
151
152 cacheBlockMask = 0;
153
154 lsq = lsq_ptr;
155
156 lsqID = id;
157
158 // Add 1 for the sentinel entry (they are circular queues).
159 LQEntries = maxLQEntries + 1;
160 SQEntries = maxSQEntries + 1;
161
162 loadQueue.resize(LQEntries);
163 storeQueue.resize(SQEntries);
164
165 depCheckShift = params->LSQDepCheckShift;
166 checkLoads = params->LSQCheckLoads;
167
168 loadHead = loadTail = 0;
169
170 storeHead = storeWBIdx = storeTail = 0;
171
172 usedPorts = 0;
173 cachePorts = params->cachePorts;
174
175 retryPkt = NULL;
176 memDepViolator = NULL;
177
178 blockedLoadSeqNum = 0;
179 needsTSO = params->needsTSO;
180}
181
182template<class Impl>
183std::string
184LSQUnit<Impl>::name() const
185{
186 if (Impl::MaxThreads == 1) {
187 return iewStage->name() + ".lsq";
188 } else {
189 return iewStage->name() + ".lsq.thread" + to_string(lsqID);
190 }
191}
192
193template<class Impl>
194void
195LSQUnit<Impl>::regStats()
196{
197 lsqForwLoads
198 .name(name() + ".forwLoads")
199 .desc("Number of loads that had data forwarded from stores");
200
201 invAddrLoads
202 .name(name() + ".invAddrLoads")
203 .desc("Number of loads ignored due to an invalid address");
204
205 lsqSquashedLoads
206 .name(name() + ".squashedLoads")
207 .desc("Number of loads squashed");
208
209 lsqIgnoredResponses
210 .name(name() + ".ignoredResponses")
211 .desc("Number of memory responses ignored because the instruction is squashed");
212
213 lsqMemOrderViolation
214 .name(name() + ".memOrderViolation")
215 .desc("Number of memory ordering violations");
216
217 lsqSquashedStores
218 .name(name() + ".squashedStores")
219 .desc("Number of stores squashed");
220
221 invAddrSwpfs
222 .name(name() + ".invAddrSwpfs")
223 .desc("Number of software prefetches ignored due to an invalid address");
224
225 lsqBlockedLoads
226 .name(name() + ".blockedLoads")
227 .desc("Number of blocked loads due to partial load-store forwarding");
228
229 lsqRescheduledLoads
230 .name(name() + ".rescheduledLoads")
231 .desc("Number of loads that were rescheduled");
232
233 lsqCacheBlocked
234 .name(name() + ".cacheBlocked")
235 .desc("Number of times an access to memory failed due to the cache being blocked");
236}
237
238template<class Impl>
239void
240LSQUnit<Impl>::setDcachePort(MasterPort *dcache_port)
241{
242 dcachePort = dcache_port;
243}
244
245template<class Impl>
246void
247LSQUnit<Impl>::clearLQ()
248{
249 loadQueue.clear();
250}
251
252template<class Impl>
253void
254LSQUnit<Impl>::clearSQ()
255{
256 storeQueue.clear();
257}
258
259template<class Impl>
260void
261LSQUnit<Impl>::switchOut()
262{
263 switchedOut = true;
264 for (int i = 0; i < loadQueue.size(); ++i) {
265 assert(!loadQueue[i]);
266 loadQueue[i] = NULL;
267 }
268
269 assert(storesToWB == 0);
270}
271
272template<class Impl>
273void
274LSQUnit<Impl>::takeOverFrom()
275{
276 switchedOut = false;
277 loads = stores = storesToWB = 0;
278
279 loadHead = loadTail = 0;
280
281 storeHead = storeWBIdx = storeTail = 0;
282
283 usedPorts = 0;
284
285 memDepViolator = NULL;
286
287 blockedLoadSeqNum = 0;
288
289 stalled = false;
290 isLoadBlocked = false;
291 loadBlockedHandled = false;
292
293 // Just incase the memory system changed out from under us
294 cacheBlockMask = 0;
295}
296
297template<class Impl>
298void
299LSQUnit<Impl>::resizeLQ(unsigned size)
300{
301 unsigned size_plus_sentinel = size + 1;
302 assert(size_plus_sentinel >= LQEntries);
303
304 if (size_plus_sentinel > LQEntries) {
305 while (size_plus_sentinel > loadQueue.size()) {
306 DynInstPtr dummy;
307 loadQueue.push_back(dummy);
308 LQEntries++;
309 }
310 } else {
311 LQEntries = size_plus_sentinel;
312 }
313
314}
315
316template<class Impl>
317void
318LSQUnit<Impl>::resizeSQ(unsigned size)
319{
320 unsigned size_plus_sentinel = size + 1;
321 if (size_plus_sentinel > SQEntries) {
322 while (size_plus_sentinel > storeQueue.size()) {
323 SQEntry dummy;
324 storeQueue.push_back(dummy);
325 SQEntries++;
326 }
327 } else {
328 SQEntries = size_plus_sentinel;
329 }
330}
331
332template <class Impl>
333void
334LSQUnit<Impl>::insert(DynInstPtr &inst)
335{
336 assert(inst->isMemRef());
337
338 assert(inst->isLoad() || inst->isStore());
339
340 if (inst->isLoad()) {
341 insertLoad(inst);
342 } else {
343 insertStore(inst);
344 }
345
346 inst->setInLSQ();
347}
348
349template <class Impl>
350void
351LSQUnit<Impl>::insertLoad(DynInstPtr &load_inst)
352{
353 assert((loadTail + 1) % LQEntries != loadHead);
354 assert(loads < LQEntries);
355
356 DPRINTF(LSQUnit, "Inserting load PC %s, idx:%i [sn:%lli]\n",
357 load_inst->pcState(), loadTail, load_inst->seqNum);
358
359 load_inst->lqIdx = loadTail;
360
361 if (stores == 0) {
362 load_inst->sqIdx = -1;
363 } else {
364 load_inst->sqIdx = storeTail;
365 }
366
367 loadQueue[loadTail] = load_inst;
368
369 incrLdIdx(loadTail);
370
371 ++loads;
372}
373
374template <class Impl>
375void
376LSQUnit<Impl>::insertStore(DynInstPtr &store_inst)
377{
378 // Make sure it is not full before inserting an instruction.
379 assert((storeTail + 1) % SQEntries != storeHead);
380 assert(stores < SQEntries);
381
382 DPRINTF(LSQUnit, "Inserting store PC %s, idx:%i [sn:%lli]\n",
383 store_inst->pcState(), storeTail, store_inst->seqNum);
384
385 store_inst->sqIdx = storeTail;
386 store_inst->lqIdx = loadTail;
387
388 storeQueue[storeTail] = SQEntry(store_inst);
389
390 incrStIdx(storeTail);
391
392 ++stores;
393}
394
395template <class Impl>
396typename Impl::DynInstPtr
397LSQUnit<Impl>::getMemDepViolator()
398{
399 DynInstPtr temp = memDepViolator;
400
401 memDepViolator = NULL;
402
403 return temp;
404}
405
406template <class Impl>
407unsigned
408LSQUnit<Impl>::numFreeEntries()
409{
410 unsigned free_lq_entries = LQEntries - loads;
411 unsigned free_sq_entries = SQEntries - stores;
412
413 // Both the LQ and SQ entries have an extra dummy entry to differentiate
414 // empty/full conditions. Subtract 1 from the free entries.
415 if (free_lq_entries < free_sq_entries) {
416 return free_lq_entries - 1;
417 } else {
418 return free_sq_entries - 1;
419 }
420}
421
422template <class Impl>
423void
424LSQUnit<Impl>::checkSnoop(PacketPtr pkt)
425{
426 int load_idx = loadHead;
427
428 if (!cacheBlockMask) {
429 assert(dcachePort);
430 Addr bs = dcachePort->peerBlockSize();
431
432 // Make sure we actually got a size
433 assert(bs != 0);
434
435 cacheBlockMask = ~(bs - 1);
436 }
437
438 // Unlock the cpu-local monitor when the CPU sees a snoop to a locked
439 // address. The CPU can speculatively execute a LL operation after a pending
440 // SC operation in the pipeline and that can make the cache monitor the CPU
441 // is connected to valid while it really shouldn't be.
442 for (int x = 0; x < cpu->numActiveThreads(); x++) {
443 ThreadContext *tc = cpu->getContext(x);
444 bool no_squash = cpu->thread[x]->noSquashFromTC;
445 cpu->thread[x]->noSquashFromTC = true;
446 TheISA::handleLockedSnoop(tc, pkt, cacheBlockMask);
447 cpu->thread[x]->noSquashFromTC = no_squash;
448 }
449
450 // If this is the only load in the LSQ we don't care
451 if (load_idx == loadTail)
452 return;
453 incrLdIdx(load_idx);
454
455 DPRINTF(LSQUnit, "Got snoop for address %#x\n", pkt->getAddr());
456 Addr invalidate_addr = pkt->getAddr() & cacheBlockMask;
457 while (load_idx != loadTail) {
458 DynInstPtr ld_inst = loadQueue[load_idx];
459
460 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) {
461 incrLdIdx(load_idx);
462 continue;
463 }
464
465 Addr load_addr = ld_inst->physEffAddr & cacheBlockMask;
466 DPRINTF(LSQUnit, "-- inst [sn:%lli] load_addr: %#x to pktAddr:%#x\n",
467 ld_inst->seqNum, load_addr, invalidate_addr);
468
469 if (load_addr == invalidate_addr) {
470 if (ld_inst->possibleLoadViolation()) {
471 DPRINTF(LSQUnit, "Conflicting load at addr %#x [sn:%lli]\n",
472 ld_inst->physEffAddr, pkt->getAddr(), ld_inst->seqNum);
473
474 // Mark the load for re-execution
475 ld_inst->fault = new ReExec;
476 } else {
477 // If a older load checks this and it's true
478 // then we might have missed the snoop
479 // in which case we need to invalidate to be sure
480 ld_inst->hitExternalSnoop(true);
481 }
482 }
483 incrLdIdx(load_idx);
484 }
485 return;
486}
487
488template <class Impl>
489Fault
490LSQUnit<Impl>::checkViolations(int load_idx, DynInstPtr &inst)
491{
492 Addr inst_eff_addr1 = inst->effAddr >> depCheckShift;
493 Addr inst_eff_addr2 = (inst->effAddr + inst->effSize - 1) >> depCheckShift;
494
495 /** @todo in theory you only need to check an instruction that has executed
496 * however, there isn't a good way in the pipeline at the moment to check
497 * all instructions that will execute before the store writes back. Thus,
498 * like the implementation that came before it, we're overly conservative.
499 */
500 while (load_idx != loadTail) {
501 DynInstPtr ld_inst = loadQueue[load_idx];
502 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) {
503 incrLdIdx(load_idx);
504 continue;
505 }
506
507 Addr ld_eff_addr1 = ld_inst->effAddr >> depCheckShift;
508 Addr ld_eff_addr2 =
509 (ld_inst->effAddr + ld_inst->effSize - 1) >> depCheckShift;
510
511 if (inst_eff_addr2 >= ld_eff_addr1 && inst_eff_addr1 <= ld_eff_addr2) {
512 if (inst->isLoad()) {
513 // If this load is to the same block as an external snoop
514 // invalidate that we've observed then the load needs to be
515 // squashed as it could have newer data
516 if (ld_inst->hitExternalSnoop()) {
517 if (!memDepViolator ||
518 ld_inst->seqNum < memDepViolator->seqNum) {
519 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] "
520 "and [sn:%lli] at address %#x\n",
521 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
522 memDepViolator = ld_inst;
523
524 ++lsqMemOrderViolation;
525
526 return new GenericISA::M5PanicFault(
527 "Detected fault with inst [sn:%lli] and "
528 "[sn:%lli] at address %#x\n",
529 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
530 }
531 }
532
533 // Otherwise, mark the load has a possible load violation
534 // and if we see a snoop before it's commited, we need to squash
535 ld_inst->possibleLoadViolation(true);
536 DPRINTF(LSQUnit, "Found possible load violaiton at addr: %#x"
537 " between instructions [sn:%lli] and [sn:%lli]\n",
538 inst_eff_addr1, inst->seqNum, ld_inst->seqNum);
539 } else {
540 // A load/store incorrectly passed this store.
541 // Check if we already have a violator, or if it's newer
542 // squash and refetch.
543 if (memDepViolator && ld_inst->seqNum > memDepViolator->seqNum)
544 break;
545
546 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] and "
547 "[sn:%lli] at address %#x\n",
548 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
549 memDepViolator = ld_inst;
550
551 ++lsqMemOrderViolation;
552
553 return new GenericISA::M5PanicFault("Detected fault with "
554 "inst [sn:%lli] and [sn:%lli] at address %#x\n",
555 inst->seqNum, ld_inst->seqNum, ld_eff_addr1);
556 }
557 }
558
559 incrLdIdx(load_idx);
560 }
561 return NoFault;
562}
563
564
565
566
567template <class Impl>
568Fault
569LSQUnit<Impl>::executeLoad(DynInstPtr &inst)
570{
571 using namespace TheISA;
572 // Execute a specific load.
573 Fault load_fault = NoFault;
574
575 DPRINTF(LSQUnit, "Executing load PC %s, [sn:%lli]\n",
576 inst->pcState(), inst->seqNum);
577
578 assert(!inst->isSquashed());
579
580 load_fault = inst->initiateAcc();
581
582 if (inst->isTranslationDelayed() &&
583 load_fault == NoFault)
584 return load_fault;
585
586 // If the instruction faulted or predicated false, then we need to send it
587 // along to commit without the instruction completing.
588 if (load_fault != NoFault || inst->readPredicate() == false) {
589 // Send this instruction to commit, also make sure iew stage
590 // realizes there is activity.
591 // Mark it as executed unless it is an uncached load that
592 // needs to hit the head of commit.
593 if (inst->readPredicate() == false)
594 inst->forwardOldRegs();
595 DPRINTF(LSQUnit, "Load [sn:%lli] not executed from %s\n",
596 inst->seqNum,
597 (load_fault != NoFault ? "fault" : "predication"));
598 if (!(inst->hasRequest() && inst->uncacheable()) ||
599 inst->isAtCommit()) {
600 inst->setExecuted();
601 }
602 iewStage->instToCommit(inst);
603 iewStage->activityThisCycle();
604 } else if (!loadBlocked()) {
605 assert(inst->effAddrValid());
606 int load_idx = inst->lqIdx;
607 incrLdIdx(load_idx);
608
609 if (checkLoads)
610 return checkViolations(load_idx, inst);
611 }
612
613 return load_fault;
614}
615
616template <class Impl>
617Fault
618LSQUnit<Impl>::executeStore(DynInstPtr &store_inst)
619{
620 using namespace TheISA;
621 // Make sure that a store exists.
622 assert(stores != 0);
623
624 int store_idx = store_inst->sqIdx;
625
626 DPRINTF(LSQUnit, "Executing store PC %s [sn:%lli]\n",
627 store_inst->pcState(), store_inst->seqNum);
628
629 assert(!store_inst->isSquashed());
630
631 // Check the recently completed loads to see if any match this store's
632 // address. If so, then we have a memory ordering violation.
633 int load_idx = store_inst->lqIdx;
634
635 Fault store_fault = store_inst->initiateAcc();
636
637 if (store_inst->isTranslationDelayed() &&
638 store_fault == NoFault)
639 return store_fault;
640
641 if (store_inst->readPredicate() == false)
642 store_inst->forwardOldRegs();
643
644 if (storeQueue[store_idx].size == 0) {
645 DPRINTF(LSQUnit,"Fault on Store PC %s, [sn:%lli], Size = 0\n",
646 store_inst->pcState(), store_inst->seqNum);
647
648 return store_fault;
649 } else if (store_inst->readPredicate() == false) {
650 DPRINTF(LSQUnit, "Store [sn:%lli] not executed from predication\n",
651 store_inst->seqNum);
652 return store_fault;
653 }
654
655 assert(store_fault == NoFault);
656
657 if (store_inst->isStoreConditional()) {
658 // Store conditionals need to set themselves as able to
659 // writeback if we haven't had a fault by here.
660 storeQueue[store_idx].canWB = true;
661
662 ++storesToWB;
663 }
664
665 return checkViolations(load_idx, store_inst);
666
667}
668
669template <class Impl>
670void
671LSQUnit<Impl>::commitLoad()
672{
673 assert(loadQueue[loadHead]);
674
675 DPRINTF(LSQUnit, "Committing head load instruction, PC %s\n",
676 loadQueue[loadHead]->pcState());
677
678 loadQueue[loadHead] = NULL;
679
680 incrLdIdx(loadHead);
681
682 --loads;
683}
684
685template <class Impl>
686void
687LSQUnit<Impl>::commitLoads(InstSeqNum &youngest_inst)
688{
689 assert(loads == 0 || loadQueue[loadHead]);
690
691 while (loads != 0 && loadQueue[loadHead]->seqNum <= youngest_inst) {
692 commitLoad();
693 }
694}
695
696template <class Impl>
697void
698LSQUnit<Impl>::commitStores(InstSeqNum &youngest_inst)
699{
700 assert(stores == 0 || storeQueue[storeHead].inst);
701
702 int store_idx = storeHead;
703
704 while (store_idx != storeTail) {
705 assert(storeQueue[store_idx].inst);
706 // Mark any stores that are now committed and have not yet
707 // been marked as able to write back.
708 if (!storeQueue[store_idx].canWB) {
709 if (storeQueue[store_idx].inst->seqNum > youngest_inst) {
710 break;
711 }
712 DPRINTF(LSQUnit, "Marking store as able to write back, PC "
713 "%s [sn:%lli]\n",
714 storeQueue[store_idx].inst->pcState(),
715 storeQueue[store_idx].inst->seqNum);
716
717 storeQueue[store_idx].canWB = true;
718
719 ++storesToWB;
720 }
721
722 incrStIdx(store_idx);
723 }
724}
725
726template <class Impl>
727void
728LSQUnit<Impl>::writebackPendingStore()
729{
730 if (hasPendingPkt) {
731 assert(pendingPkt != NULL);
732
733 // If the cache is blocked, this will store the packet for retry.
734 if (sendStore(pendingPkt)) {
735 storePostSend(pendingPkt);
736 }
737 pendingPkt = NULL;
738 hasPendingPkt = false;
739 }
740}
741
742template <class Impl>
743void
744LSQUnit<Impl>::writebackStores()
745{
746 // First writeback the second packet from any split store that didn't
747 // complete last cycle because there weren't enough cache ports available.
748 if (TheISA::HasUnalignedMemAcc) {
749 writebackPendingStore();
750 }
751
752 while (storesToWB > 0 &&
753 storeWBIdx != storeTail &&
754 storeQueue[storeWBIdx].inst &&
755 storeQueue[storeWBIdx].canWB &&
756 ((!needsTSO) || (!storeInFlight)) &&
757 usedPorts < cachePorts) {
758
759 if (isStoreBlocked || lsq->cacheBlocked()) {
760 DPRINTF(LSQUnit, "Unable to write back any more stores, cache"
761 " is blocked!\n");
762 break;
763 }
764
765 // Store didn't write any data so no need to write it back to
766 // memory.
767 if (storeQueue[storeWBIdx].size == 0) {
768 completeStore(storeWBIdx);
769
770 incrStIdx(storeWBIdx);
771
772 continue;
773 }
774
775 ++usedPorts;
776
777 if (storeQueue[storeWBIdx].inst->isDataPrefetch()) {
778 incrStIdx(storeWBIdx);
779
780 continue;
781 }
782
783 assert(storeQueue[storeWBIdx].req);
784 assert(!storeQueue[storeWBIdx].committed);
785
786 if (TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit) {
787 assert(storeQueue[storeWBIdx].sreqLow);
788 assert(storeQueue[storeWBIdx].sreqHigh);
789 }
790
791 DynInstPtr inst = storeQueue[storeWBIdx].inst;
792
793 Request *req = storeQueue[storeWBIdx].req;
794 RequestPtr sreqLow = storeQueue[storeWBIdx].sreqLow;
795 RequestPtr sreqHigh = storeQueue[storeWBIdx].sreqHigh;
796
797 storeQueue[storeWBIdx].committed = true;
798
799 assert(!inst->memData);
800 inst->memData = new uint8_t[64];
801
802 memcpy(inst->memData, storeQueue[storeWBIdx].data, req->getSize());
803
804 MemCmd command =
805 req->isSwap() ? MemCmd::SwapReq :
806 (req->isLLSC() ? MemCmd::StoreCondReq : MemCmd::WriteReq);
807 PacketPtr data_pkt;
808 PacketPtr snd_data_pkt = NULL;
809
810 LSQSenderState *state = new LSQSenderState;
811 state->isLoad = false;
812 state->idx = storeWBIdx;
813 state->inst = inst;
814
815 if (!TheISA::HasUnalignedMemAcc || !storeQueue[storeWBIdx].isSplit) {
816
817 // Build a single data packet if the store isn't split.
818 data_pkt = new Packet(req, command);
819 data_pkt->dataStatic(inst->memData);
820 data_pkt->senderState = state;
821 } else {
822 // Create two packets if the store is split in two.
823 data_pkt = new Packet(sreqLow, command);
824 snd_data_pkt = new Packet(sreqHigh, command);
825
826 data_pkt->dataStatic(inst->memData);
827 snd_data_pkt->dataStatic(inst->memData + sreqLow->getSize());
828
829 data_pkt->senderState = state;
830 snd_data_pkt->senderState = state;
831
832 state->isSplit = true;
833 state->outstanding = 2;
834
835 // Can delete the main request now.
836 delete req;
837 req = sreqLow;
838 }
839
840 DPRINTF(LSQUnit, "D-Cache: Writing back store idx:%i PC:%s "
841 "to Addr:%#x, data:%#x [sn:%lli]\n",
842 storeWBIdx, inst->pcState(),
843 req->getPaddr(), (int)*(inst->memData),
844 inst->seqNum);
845
846 // @todo: Remove this SC hack once the memory system handles it.
847 if (inst->isStoreConditional()) {
848 assert(!storeQueue[storeWBIdx].isSplit);
849 // Disable recording the result temporarily. Writing to
850 // misc regs normally updates the result, but this is not
851 // the desired behavior when handling store conditionals.
852 inst->recordResult(false);
853 bool success = TheISA::handleLockedWrite(inst.get(), req);
854 inst->recordResult(true);
855
856 if (!success) {
857 // Instantly complete this store.
858 DPRINTF(LSQUnit, "Store conditional [sn:%lli] failed. "
859 "Instantly completing it.\n",
860 inst->seqNum);
861 WritebackEvent *wb = new WritebackEvent(inst, data_pkt, this);
862 cpu->schedule(wb, curTick() + 1);
863 if (cpu->checker) {
864 // Make sure to set the LLSC data for verification
865 // if checker is loaded
866 inst->reqToVerify->setExtraData(0);
867 inst->completeAcc(data_pkt);
868 }
869 completeStore(storeWBIdx);
870 incrStIdx(storeWBIdx);
871 continue;
872 }
873 } else {
874 // Non-store conditionals do not need a writeback.
875 state->noWB = true;
876 }
877
878 bool split =
879 TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit;
880
881 ThreadContext *thread = cpu->tcBase(lsqID);
882
883 if (req->isMmappedIpr()) {
884 assert(!inst->isStoreConditional());
885 TheISA::handleIprWrite(thread, data_pkt);
886 delete data_pkt;
887 if (split) {
888 assert(snd_data_pkt->req->isMmappedIpr());
889 TheISA::handleIprWrite(thread, snd_data_pkt);
890 delete snd_data_pkt;
891 delete sreqLow;
892 delete sreqHigh;
893 }
894 delete state;
895 delete req;
896 completeStore(storeWBIdx);
897 incrStIdx(storeWBIdx);
898 } else if (!sendStore(data_pkt)) {
899 DPRINTF(IEW, "D-Cache became blocked when writing [sn:%lli], will"
900 "retry later\n",
901 inst->seqNum);
902
903 // Need to store the second packet, if split.
904 if (split) {
905 state->pktToSend = true;
906 state->pendingPacket = snd_data_pkt;
907 }
908 } else {
909
910 // If split, try to send the second packet too
911 if (split) {
912 assert(snd_data_pkt);
913
914 // Ensure there are enough ports to use.
915 if (usedPorts < cachePorts) {
916 ++usedPorts;
917 if (sendStore(snd_data_pkt)) {
918 storePostSend(snd_data_pkt);
919 } else {
920 DPRINTF(IEW, "D-Cache became blocked when writing"
921 " [sn:%lli] second packet, will retry later\n",
922 inst->seqNum);
923 }
924 } else {
925
926 // Store the packet for when there's free ports.
927 assert(pendingPkt == NULL);
928 pendingPkt = snd_data_pkt;
929 hasPendingPkt = true;
930 }
931 } else {
932
933 // Not a split store.
934 storePostSend(data_pkt);
935 }
936 }
937 }
938
939 // Not sure this should set it to 0.
940 usedPorts = 0;
941
942 assert(stores >= 0 && storesToWB >= 0);
943}
944
945/*template <class Impl>
946void
947LSQUnit<Impl>::removeMSHR(InstSeqNum seqNum)
948{
949 list<InstSeqNum>::iterator mshr_it = find(mshrSeqNums.begin(),
950 mshrSeqNums.end(),
951 seqNum);
952
953 if (mshr_it != mshrSeqNums.end()) {
954 mshrSeqNums.erase(mshr_it);
955 DPRINTF(LSQUnit, "Removing MSHR. count = %i\n",mshrSeqNums.size());
956 }
957}*/
958
959template <class Impl>
960void
961LSQUnit<Impl>::squash(const InstSeqNum &squashed_num)
962{
963 DPRINTF(LSQUnit, "Squashing until [sn:%lli]!"
964 "(Loads:%i Stores:%i)\n", squashed_num, loads, stores);
965
966 int load_idx = loadTail;
967 decrLdIdx(load_idx);
968
969 while (loads != 0 && loadQueue[load_idx]->seqNum > squashed_num) {
970 DPRINTF(LSQUnit,"Load Instruction PC %s squashed, "
971 "[sn:%lli]\n",
972 loadQueue[load_idx]->pcState(),
973 loadQueue[load_idx]->seqNum);
974
975 if (isStalled() && load_idx == stallingLoadIdx) {
976 stalled = false;
977 stallingStoreIsn = 0;
978 stallingLoadIdx = 0;
979 }
980
981 // Clear the smart pointer to make sure it is decremented.
982 loadQueue[load_idx]->setSquashed();
983 loadQueue[load_idx] = NULL;
984 --loads;
985
986 // Inefficient!
987 loadTail = load_idx;
988
989 decrLdIdx(load_idx);
990 ++lsqSquashedLoads;
991 }
992
993 if (isLoadBlocked) {
994 if (squashed_num < blockedLoadSeqNum) {
995 isLoadBlocked = false;
996 loadBlockedHandled = false;
997 blockedLoadSeqNum = 0;
998 }
999 }
1000
1001 if (memDepViolator && squashed_num < memDepViolator->seqNum) {
1002 memDepViolator = NULL;
1003 }
1004
1005 int store_idx = storeTail;
1006 decrStIdx(store_idx);
1007
1008 while (stores != 0 &&
1009 storeQueue[store_idx].inst->seqNum > squashed_num) {
1010 // Instructions marked as can WB are already committed.
1011 if (storeQueue[store_idx].canWB) {
1012 break;
1013 }
1014
1015 DPRINTF(LSQUnit,"Store Instruction PC %s squashed, "
1016 "idx:%i [sn:%lli]\n",
1017 storeQueue[store_idx].inst->pcState(),
1018 store_idx, storeQueue[store_idx].inst->seqNum);
1019
1020 // I don't think this can happen. It should have been cleared
1021 // by the stalling load.
1022 if (isStalled() &&
1023 storeQueue[store_idx].inst->seqNum == stallingStoreIsn) {
1024 panic("Is stalled should have been cleared by stalling load!\n");
1025 stalled = false;
1026 stallingStoreIsn = 0;
1027 }
1028
1029 // Clear the smart pointer to make sure it is decremented.
1030 storeQueue[store_idx].inst->setSquashed();
1031 storeQueue[store_idx].inst = NULL;
1032 storeQueue[store_idx].canWB = 0;
1033
1034 // Must delete request now that it wasn't handed off to
1035 // memory. This is quite ugly. @todo: Figure out the proper
1036 // place to really handle request deletes.
1037 delete storeQueue[store_idx].req;
1038 if (TheISA::HasUnalignedMemAcc && storeQueue[store_idx].isSplit) {
1039 delete storeQueue[store_idx].sreqLow;
1040 delete storeQueue[store_idx].sreqHigh;
1041
1042 storeQueue[store_idx].sreqLow = NULL;
1043 storeQueue[store_idx].sreqHigh = NULL;
1044 }
1045
1046 storeQueue[store_idx].req = NULL;
1047 --stores;
1048
1049 // Inefficient!
1050 storeTail = store_idx;
1051
1052 decrStIdx(store_idx);
1053 ++lsqSquashedStores;
1054 }
1055}
1056
1057template <class Impl>
1058void
1059LSQUnit<Impl>::storePostSend(PacketPtr pkt)
1060{
1061 if (isStalled() &&
1062 storeQueue[storeWBIdx].inst->seqNum == stallingStoreIsn) {
1063 DPRINTF(LSQUnit, "Unstalling, stalling store [sn:%lli] "
1064 "load idx:%i\n",
1065 stallingStoreIsn, stallingLoadIdx);
1066 stalled = false;
1067 stallingStoreIsn = 0;
1068 iewStage->replayMemInst(loadQueue[stallingLoadIdx]);
1069 }
1070
1071 if (!storeQueue[storeWBIdx].inst->isStoreConditional()) {
1072 // The store is basically completed at this time. This
1073 // only works so long as the checker doesn't try to
1074 // verify the value in memory for stores.
1075 storeQueue[storeWBIdx].inst->setCompleted();
1076
1077 if (cpu->checker) {
1078 cpu->checker->verify(storeQueue[storeWBIdx].inst);
1079 }
1080 }
1081
1082 if (needsTSO) {
1083 storeInFlight = true;
1084 }
1085
1086 incrStIdx(storeWBIdx);
1087}
1088
1089template <class Impl>
1090void
1091LSQUnit<Impl>::writeback(DynInstPtr &inst, PacketPtr pkt)
1092{
1093 iewStage->wakeCPU();
1094
1095 // Squashed instructions do not need to complete their access.
1096 if (inst->isSquashed()) {
1097 iewStage->decrWb(inst->seqNum);
1098 assert(!inst->isStore());
1099 ++lsqIgnoredResponses;
1100 return;
1101 }
1102
1103 if (!inst->isExecuted()) {
1104 inst->setExecuted();
1105
1106 // Complete access to copy data to proper place.
1107 inst->completeAcc(pkt);
1108 }
1109
1110 // Need to insert instruction into queue to commit
1111 iewStage->instToCommit(inst);
1112
1113 iewStage->activityThisCycle();
1114
1115 // see if this load changed the PC
1116 iewStage->checkMisprediction(inst);
1117}
1118
1119template <class Impl>
1120void
1121LSQUnit<Impl>::completeStore(int store_idx)
1122{
1123 assert(storeQueue[store_idx].inst);
1124 storeQueue[store_idx].completed = true;
1125 --storesToWB;
1126 // A bit conservative because a store completion may not free up entries,
1127 // but hopefully avoids two store completions in one cycle from making
1128 // the CPU tick twice.
1129 cpu->wakeCPU();
1130 cpu->activityThisCycle();
1131
1132 if (store_idx == storeHead) {
1133 do {
1134 incrStIdx(storeHead);
1135
1136 --stores;
1137 } while (storeQueue[storeHead].completed &&
1138 storeHead != storeTail);
1139
1140 iewStage->updateLSQNextCycle = true;
1141 }
1142
1143 DPRINTF(LSQUnit, "Completing store [sn:%lli], idx:%i, store head "
1144 "idx:%i\n",
1145 storeQueue[store_idx].inst->seqNum, store_idx, storeHead);
1146
1147 if (isStalled() &&
1148 storeQueue[store_idx].inst->seqNum == stallingStoreIsn) {
1149 DPRINTF(LSQUnit, "Unstalling, stalling store [sn:%lli] "
1150 "load idx:%i\n",
1151 stallingStoreIsn, stallingLoadIdx);
1152 stalled = false;
1153 stallingStoreIsn = 0;
1154 iewStage->replayMemInst(loadQueue[stallingLoadIdx]);
1155 }
1156
1157 storeQueue[store_idx].inst->setCompleted();
1158
1159 if (needsTSO) {
1160 storeInFlight = false;
1161 }
1162
1163 // Tell the checker we've completed this instruction. Some stores
1164 // may get reported twice to the checker, but the checker can
1165 // handle that case.
1166 if (cpu->checker) {
1167 cpu->checker->verify(storeQueue[store_idx].inst);
1168 }
1169}
1170
1171template <class Impl>
1172bool
1173LSQUnit<Impl>::sendStore(PacketPtr data_pkt)
1174{
1175 if (!dcachePort->sendTimingReq(data_pkt)) {
1176 // Need to handle becoming blocked on a store.
1177 isStoreBlocked = true;
1178 ++lsqCacheBlocked;
1179 assert(retryPkt == NULL);
1180 retryPkt = data_pkt;
1181 lsq->setRetryTid(lsqID);
1182 return false;
1183 }
1184 return true;
1185}
1186
1187template <class Impl>
1188void
1189LSQUnit<Impl>::recvRetry()
1190{
1191 if (isStoreBlocked) {
1192 DPRINTF(LSQUnit, "Receiving retry: store blocked\n");
1193 assert(retryPkt != NULL);
1194
1195 LSQSenderState *state =
1196 dynamic_cast<LSQSenderState *>(retryPkt->senderState);
1197
1198 if (dcachePort->sendTimingReq(retryPkt)) {
1199 // Don't finish the store unless this is the last packet.
1200 if (!TheISA::HasUnalignedMemAcc || !state->pktToSend ||
1201 state->pendingPacket == retryPkt) {
1202 state->pktToSend = false;
1203 storePostSend(retryPkt);
1204 }
1205 retryPkt = NULL;
1206 isStoreBlocked = false;
1207 lsq->setRetryTid(InvalidThreadID);
1208
1209 // Send any outstanding packet.
1210 if (TheISA::HasUnalignedMemAcc && state->pktToSend) {
1211 assert(state->pendingPacket);
1212 if (sendStore(state->pendingPacket)) {
1213 storePostSend(state->pendingPacket);
1214 }
1215 }
1216 } else {
1217 // Still blocked!
1218 ++lsqCacheBlocked;
1219 lsq->setRetryTid(lsqID);
1220 }
1221 } else if (isLoadBlocked) {
1222 DPRINTF(LSQUnit, "Loads squash themselves and all younger insts, "
1223 "no need to resend packet.\n");
1224 } else {
1225 DPRINTF(LSQUnit, "Retry received but LSQ is no longer blocked.\n");
1226 }
1227}
1228
1229template <class Impl>
1230inline void
1231LSQUnit<Impl>::incrStIdx(int &store_idx) const
1232{
1233 if (++store_idx >= SQEntries)
1234 store_idx = 0;
1235}
1236
1237template <class Impl>
1238inline void
1239LSQUnit<Impl>::decrStIdx(int &store_idx) const
1240{
1241 if (--store_idx < 0)
1242 store_idx += SQEntries;
1243}
1244
1245template <class Impl>
1246inline void
1247LSQUnit<Impl>::incrLdIdx(int &load_idx) const
1248{
1249 if (++load_idx >= LQEntries)
1250 load_idx = 0;
1251}
1252
1253template <class Impl>
1254inline void
1255LSQUnit<Impl>::decrLdIdx(int &load_idx) const
1256{
1257 if (--load_idx < 0)
1258 load_idx += LQEntries;
1259}
1260
1261template <class Impl>
1262void
1263LSQUnit<Impl>::dumpInsts() const
1264{
1265 cprintf("Load store queue: Dumping instructions.\n");
1266 cprintf("Load queue size: %i\n", loads);
1267 cprintf("Load queue: ");
1268
1269 int load_idx = loadHead;
1270
1271 while (load_idx != loadTail && loadQueue[load_idx]) {
1272 const DynInstPtr &inst(loadQueue[load_idx]);
1273 cprintf("%s.[sn:%i] ", inst->pcState(), inst->seqNum);
1274
1275 incrLdIdx(load_idx);
1276 }
1277 cprintf("\n");
1278
1279 cprintf("Store queue size: %i\n", stores);
1280 cprintf("Store queue: ");
1281
1282 int store_idx = storeHead;
1283
1284 while (store_idx != storeTail && storeQueue[store_idx].inst) {
1285 const DynInstPtr &inst(storeQueue[store_idx].inst);
1286 cprintf("%s.[sn:%i] ", inst->pcState(), inst->seqNum);
1287
1288 incrStIdx(store_idx);
1289 }
1290
1291 cprintf("\n");
1292}