lsq_unit_impl.hh revision 9165:f9e3dac185ba
1/* 2 * Copyright (c) 2010-2011 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> 423int 424LSQUnit<Impl>::numLoadsReady() 425{ 426 int load_idx = loadHead; 427 int retval = 0; 428 429 while (load_idx != loadTail) { 430 assert(loadQueue[load_idx]); 431 432 if (loadQueue[load_idx]->readyToIssue()) { 433 ++retval; 434 } 435 } 436 437 return retval; 438} 439 440template <class Impl> 441void 442LSQUnit<Impl>::checkSnoop(PacketPtr pkt) 443{ 444 int load_idx = loadHead; 445 446 if (!cacheBlockMask) { 447 assert(dcachePort); 448 Addr bs = dcachePort->peerBlockSize(); 449 450 // Make sure we actually got a size 451 assert(bs != 0); 452 453 cacheBlockMask = ~(bs - 1); 454 } 455 456 // If this is the only load in the LSQ we don't care 457 if (load_idx == loadTail) 458 return; 459 incrLdIdx(load_idx); 460 461 DPRINTF(LSQUnit, "Got snoop for address %#x\n", pkt->getAddr()); 462 Addr invalidate_addr = pkt->getAddr() & cacheBlockMask; 463 while (load_idx != loadTail) { 464 DynInstPtr ld_inst = loadQueue[load_idx]; 465 466 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) { 467 incrLdIdx(load_idx); 468 continue; 469 } 470 471 Addr load_addr = ld_inst->physEffAddr & cacheBlockMask; 472 DPRINTF(LSQUnit, "-- inst [sn:%lli] load_addr: %#x to pktAddr:%#x\n", 473 ld_inst->seqNum, load_addr, invalidate_addr); 474 475 if (load_addr == invalidate_addr) { 476 if (ld_inst->possibleLoadViolation()) { 477 DPRINTF(LSQUnit, "Conflicting load at addr %#x [sn:%lli]\n", 478 ld_inst->physEffAddr, pkt->getAddr(), ld_inst->seqNum); 479 480 // Mark the load for re-execution 481 ld_inst->fault = new ReExec; 482 } else { 483 // If a older load checks this and it's true 484 // then we might have missed the snoop 485 // in which case we need to invalidate to be sure 486 ld_inst->hitExternalSnoop(true); 487 } 488 } 489 incrLdIdx(load_idx); 490 } 491 return; 492} 493 494template <class Impl> 495Fault 496LSQUnit<Impl>::checkViolations(int load_idx, DynInstPtr &inst) 497{ 498 Addr inst_eff_addr1 = inst->effAddr >> depCheckShift; 499 Addr inst_eff_addr2 = (inst->effAddr + inst->effSize - 1) >> depCheckShift; 500 501 /** @todo in theory you only need to check an instruction that has executed 502 * however, there isn't a good way in the pipeline at the moment to check 503 * all instructions that will execute before the store writes back. Thus, 504 * like the implementation that came before it, we're overly conservative. 505 */ 506 while (load_idx != loadTail) { 507 DynInstPtr ld_inst = loadQueue[load_idx]; 508 if (!ld_inst->effAddrValid() || ld_inst->uncacheable()) { 509 incrLdIdx(load_idx); 510 continue; 511 } 512 513 Addr ld_eff_addr1 = ld_inst->effAddr >> depCheckShift; 514 Addr ld_eff_addr2 = 515 (ld_inst->effAddr + ld_inst->effSize - 1) >> depCheckShift; 516 517 if (inst_eff_addr2 >= ld_eff_addr1 && inst_eff_addr1 <= ld_eff_addr2) { 518 if (inst->isLoad()) { 519 // If this load is to the same block as an external snoop 520 // invalidate that we've observed then the load needs to be 521 // squashed as it could have newer data 522 if (ld_inst->hitExternalSnoop()) { 523 if (!memDepViolator || 524 ld_inst->seqNum < memDepViolator->seqNum) { 525 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] " 526 "and [sn:%lli] at address %#x\n", 527 inst->seqNum, ld_inst->seqNum, ld_eff_addr1); 528 memDepViolator = ld_inst; 529 530 ++lsqMemOrderViolation; 531 532 return new GenericISA::M5PanicFault( 533 "Detected fault with inst [sn:%lli] and " 534 "[sn:%lli] at address %#x\n", 535 inst->seqNum, ld_inst->seqNum, ld_eff_addr1); 536 } 537 } 538 539 // Otherwise, mark the load has a possible load violation 540 // and if we see a snoop before it's commited, we need to squash 541 ld_inst->possibleLoadViolation(true); 542 DPRINTF(LSQUnit, "Found possible load violaiton at addr: %#x" 543 " between instructions [sn:%lli] and [sn:%lli]\n", 544 inst_eff_addr1, inst->seqNum, ld_inst->seqNum); 545 } else { 546 // A load/store incorrectly passed this store. 547 // Check if we already have a violator, or if it's newer 548 // squash and refetch. 549 if (memDepViolator && ld_inst->seqNum > memDepViolator->seqNum) 550 break; 551 552 DPRINTF(LSQUnit, "Detected fault with inst [sn:%lli] and " 553 "[sn:%lli] at address %#x\n", 554 inst->seqNum, ld_inst->seqNum, ld_eff_addr1); 555 memDepViolator = ld_inst; 556 557 ++lsqMemOrderViolation; 558 559 return new GenericISA::M5PanicFault("Detected fault with " 560 "inst [sn:%lli] and [sn:%lli] at address %#x\n", 561 inst->seqNum, ld_inst->seqNum, ld_eff_addr1); 562 } 563 } 564 565 incrLdIdx(load_idx); 566 } 567 return NoFault; 568} 569 570 571 572 573template <class Impl> 574Fault 575LSQUnit<Impl>::executeLoad(DynInstPtr &inst) 576{ 577 using namespace TheISA; 578 // Execute a specific load. 579 Fault load_fault = NoFault; 580 581 DPRINTF(LSQUnit, "Executing load PC %s, [sn:%lli]\n", 582 inst->pcState(), inst->seqNum); 583 584 assert(!inst->isSquashed()); 585 586 load_fault = inst->initiateAcc(); 587 588 if (inst->isTranslationDelayed() && 589 load_fault == NoFault) 590 return load_fault; 591 592 // If the instruction faulted or predicated false, then we need to send it 593 // along to commit without the instruction completing. 594 if (load_fault != NoFault || inst->readPredicate() == false) { 595 // Send this instruction to commit, also make sure iew stage 596 // realizes there is activity. 597 // Mark it as executed unless it is an uncached load that 598 // needs to hit the head of commit. 599 if (inst->readPredicate() == false) 600 inst->forwardOldRegs(); 601 DPRINTF(LSQUnit, "Load [sn:%lli] not executed from %s\n", 602 inst->seqNum, 603 (load_fault != NoFault ? "fault" : "predication")); 604 if (!(inst->hasRequest() && inst->uncacheable()) || 605 inst->isAtCommit()) { 606 inst->setExecuted(); 607 } 608 iewStage->instToCommit(inst); 609 iewStage->activityThisCycle(); 610 } else if (!loadBlocked()) { 611 assert(inst->effAddrValid()); 612 int load_idx = inst->lqIdx; 613 incrLdIdx(load_idx); 614 615 if (checkLoads) 616 return checkViolations(load_idx, inst); 617 } 618 619 return load_fault; 620} 621 622template <class Impl> 623Fault 624LSQUnit<Impl>::executeStore(DynInstPtr &store_inst) 625{ 626 using namespace TheISA; 627 // Make sure that a store exists. 628 assert(stores != 0); 629 630 int store_idx = store_inst->sqIdx; 631 632 DPRINTF(LSQUnit, "Executing store PC %s [sn:%lli]\n", 633 store_inst->pcState(), store_inst->seqNum); 634 635 assert(!store_inst->isSquashed()); 636 637 // Check the recently completed loads to see if any match this store's 638 // address. If so, then we have a memory ordering violation. 639 int load_idx = store_inst->lqIdx; 640 641 Fault store_fault = store_inst->initiateAcc(); 642 643 if (store_inst->isTranslationDelayed() && 644 store_fault == NoFault) 645 return store_fault; 646 647 if (store_inst->readPredicate() == false) 648 store_inst->forwardOldRegs(); 649 650 if (storeQueue[store_idx].size == 0) { 651 DPRINTF(LSQUnit,"Fault on Store PC %s, [sn:%lli], Size = 0\n", 652 store_inst->pcState(), store_inst->seqNum); 653 654 return store_fault; 655 } else if (store_inst->readPredicate() == false) { 656 DPRINTF(LSQUnit, "Store [sn:%lli] not executed from predication\n", 657 store_inst->seqNum); 658 return store_fault; 659 } 660 661 assert(store_fault == NoFault); 662 663 if (store_inst->isStoreConditional()) { 664 // Store conditionals need to set themselves as able to 665 // writeback if we haven't had a fault by here. 666 storeQueue[store_idx].canWB = true; 667 668 ++storesToWB; 669 } 670 671 return checkViolations(load_idx, store_inst); 672 673} 674 675template <class Impl> 676void 677LSQUnit<Impl>::commitLoad() 678{ 679 assert(loadQueue[loadHead]); 680 681 DPRINTF(LSQUnit, "Committing head load instruction, PC %s\n", 682 loadQueue[loadHead]->pcState()); 683 684 loadQueue[loadHead] = NULL; 685 686 incrLdIdx(loadHead); 687 688 --loads; 689} 690 691template <class Impl> 692void 693LSQUnit<Impl>::commitLoads(InstSeqNum &youngest_inst) 694{ 695 assert(loads == 0 || loadQueue[loadHead]); 696 697 while (loads != 0 && loadQueue[loadHead]->seqNum <= youngest_inst) { 698 commitLoad(); 699 } 700} 701 702template <class Impl> 703void 704LSQUnit<Impl>::commitStores(InstSeqNum &youngest_inst) 705{ 706 assert(stores == 0 || storeQueue[storeHead].inst); 707 708 int store_idx = storeHead; 709 710 while (store_idx != storeTail) { 711 assert(storeQueue[store_idx].inst); 712 // Mark any stores that are now committed and have not yet 713 // been marked as able to write back. 714 if (!storeQueue[store_idx].canWB) { 715 if (storeQueue[store_idx].inst->seqNum > youngest_inst) { 716 break; 717 } 718 DPRINTF(LSQUnit, "Marking store as able to write back, PC " 719 "%s [sn:%lli]\n", 720 storeQueue[store_idx].inst->pcState(), 721 storeQueue[store_idx].inst->seqNum); 722 723 storeQueue[store_idx].canWB = true; 724 725 ++storesToWB; 726 } 727 728 incrStIdx(store_idx); 729 } 730} 731 732template <class Impl> 733void 734LSQUnit<Impl>::writebackPendingStore() 735{ 736 if (hasPendingPkt) { 737 assert(pendingPkt != NULL); 738 739 // If the cache is blocked, this will store the packet for retry. 740 if (sendStore(pendingPkt)) { 741 storePostSend(pendingPkt); 742 } 743 pendingPkt = NULL; 744 hasPendingPkt = false; 745 } 746} 747 748template <class Impl> 749void 750LSQUnit<Impl>::writebackStores() 751{ 752 // First writeback the second packet from any split store that didn't 753 // complete last cycle because there weren't enough cache ports available. 754 if (TheISA::HasUnalignedMemAcc) { 755 writebackPendingStore(); 756 } 757 758 while (storesToWB > 0 && 759 storeWBIdx != storeTail && 760 storeQueue[storeWBIdx].inst && 761 storeQueue[storeWBIdx].canWB && 762 ((!needsTSO) || (!storeInFlight)) && 763 usedPorts < cachePorts) { 764 765 if (isStoreBlocked || lsq->cacheBlocked()) { 766 DPRINTF(LSQUnit, "Unable to write back any more stores, cache" 767 " is blocked!\n"); 768 break; 769 } 770 771 // Store didn't write any data so no need to write it back to 772 // memory. 773 if (storeQueue[storeWBIdx].size == 0) { 774 completeStore(storeWBIdx); 775 776 incrStIdx(storeWBIdx); 777 778 continue; 779 } 780 781 ++usedPorts; 782 783 if (storeQueue[storeWBIdx].inst->isDataPrefetch()) { 784 incrStIdx(storeWBIdx); 785 786 continue; 787 } 788 789 assert(storeQueue[storeWBIdx].req); 790 assert(!storeQueue[storeWBIdx].committed); 791 792 if (TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit) { 793 assert(storeQueue[storeWBIdx].sreqLow); 794 assert(storeQueue[storeWBIdx].sreqHigh); 795 } 796 797 DynInstPtr inst = storeQueue[storeWBIdx].inst; 798 799 Request *req = storeQueue[storeWBIdx].req; 800 RequestPtr sreqLow = storeQueue[storeWBIdx].sreqLow; 801 RequestPtr sreqHigh = storeQueue[storeWBIdx].sreqHigh; 802 803 storeQueue[storeWBIdx].committed = true; 804 805 assert(!inst->memData); 806 inst->memData = new uint8_t[64]; 807 808 memcpy(inst->memData, storeQueue[storeWBIdx].data, req->getSize()); 809 810 MemCmd command = 811 req->isSwap() ? MemCmd::SwapReq : 812 (req->isLLSC() ? MemCmd::StoreCondReq : MemCmd::WriteReq); 813 PacketPtr data_pkt; 814 PacketPtr snd_data_pkt = NULL; 815 816 LSQSenderState *state = new LSQSenderState; 817 state->isLoad = false; 818 state->idx = storeWBIdx; 819 state->inst = inst; 820 821 if (!TheISA::HasUnalignedMemAcc || !storeQueue[storeWBIdx].isSplit) { 822 823 // Build a single data packet if the store isn't split. 824 data_pkt = new Packet(req, command); 825 data_pkt->dataStatic(inst->memData); 826 data_pkt->senderState = state; 827 } else { 828 // Create two packets if the store is split in two. 829 data_pkt = new Packet(sreqLow, command); 830 snd_data_pkt = new Packet(sreqHigh, command); 831 832 data_pkt->dataStatic(inst->memData); 833 snd_data_pkt->dataStatic(inst->memData + sreqLow->getSize()); 834 835 data_pkt->senderState = state; 836 snd_data_pkt->senderState = state; 837 838 state->isSplit = true; 839 state->outstanding = 2; 840 841 // Can delete the main request now. 842 delete req; 843 req = sreqLow; 844 } 845 846 DPRINTF(LSQUnit, "D-Cache: Writing back store idx:%i PC:%s " 847 "to Addr:%#x, data:%#x [sn:%lli]\n", 848 storeWBIdx, inst->pcState(), 849 req->getPaddr(), (int)*(inst->memData), 850 inst->seqNum); 851 852 // @todo: Remove this SC hack once the memory system handles it. 853 if (inst->isStoreConditional()) { 854 assert(!storeQueue[storeWBIdx].isSplit); 855 // Disable recording the result temporarily. Writing to 856 // misc regs normally updates the result, but this is not 857 // the desired behavior when handling store conditionals. 858 inst->recordResult(false); 859 bool success = TheISA::handleLockedWrite(inst.get(), req); 860 inst->recordResult(true); 861 862 if (!success) { 863 // Instantly complete this store. 864 DPRINTF(LSQUnit, "Store conditional [sn:%lli] failed. " 865 "Instantly completing it.\n", 866 inst->seqNum); 867 WritebackEvent *wb = new WritebackEvent(inst, data_pkt, this); 868 cpu->schedule(wb, curTick() + 1); 869 if (cpu->checker) { 870 // Make sure to set the LLSC data for verification 871 // if checker is loaded 872 inst->reqToVerify->setExtraData(0); 873 inst->completeAcc(data_pkt); 874 } 875 completeStore(storeWBIdx); 876 incrStIdx(storeWBIdx); 877 continue; 878 } 879 } else { 880 // Non-store conditionals do not need a writeback. 881 state->noWB = true; 882 } 883 884 bool split = 885 TheISA::HasUnalignedMemAcc && storeQueue[storeWBIdx].isSplit; 886 887 ThreadContext *thread = cpu->tcBase(lsqID); 888 889 if (req->isMmappedIpr()) { 890 assert(!inst->isStoreConditional()); 891 TheISA::handleIprWrite(thread, data_pkt); 892 delete data_pkt; 893 if (split) { 894 assert(snd_data_pkt->req->isMmappedIpr()); 895 TheISA::handleIprWrite(thread, snd_data_pkt); 896 delete snd_data_pkt; 897 delete sreqLow; 898 delete sreqHigh; 899 } 900 delete state; 901 delete req; 902 completeStore(storeWBIdx); 903 incrStIdx(storeWBIdx); 904 } else if (!sendStore(data_pkt)) { 905 DPRINTF(IEW, "D-Cache became blocked when writing [sn:%lli], will" 906 "retry later\n", 907 inst->seqNum); 908 909 // Need to store the second packet, if split. 910 if (split) { 911 state->pktToSend = true; 912 state->pendingPacket = snd_data_pkt; 913 } 914 } else { 915 916 // If split, try to send the second packet too 917 if (split) { 918 assert(snd_data_pkt); 919 920 // Ensure there are enough ports to use. 921 if (usedPorts < cachePorts) { 922 ++usedPorts; 923 if (sendStore(snd_data_pkt)) { 924 storePostSend(snd_data_pkt); 925 } else { 926 DPRINTF(IEW, "D-Cache became blocked when writing" 927 " [sn:%lli] second packet, will retry later\n", 928 inst->seqNum); 929 } 930 } else { 931 932 // Store the packet for when there's free ports. 933 assert(pendingPkt == NULL); 934 pendingPkt = snd_data_pkt; 935 hasPendingPkt = true; 936 } 937 } else { 938 939 // Not a split store. 940 storePostSend(data_pkt); 941 } 942 } 943 } 944 945 // Not sure this should set it to 0. 946 usedPorts = 0; 947 948 assert(stores >= 0 && storesToWB >= 0); 949} 950 951/*template <class Impl> 952void 953LSQUnit<Impl>::removeMSHR(InstSeqNum seqNum) 954{ 955 list<InstSeqNum>::iterator mshr_it = find(mshrSeqNums.begin(), 956 mshrSeqNums.end(), 957 seqNum); 958 959 if (mshr_it != mshrSeqNums.end()) { 960 mshrSeqNums.erase(mshr_it); 961 DPRINTF(LSQUnit, "Removing MSHR. count = %i\n",mshrSeqNums.size()); 962 } 963}*/ 964 965template <class Impl> 966void 967LSQUnit<Impl>::squash(const InstSeqNum &squashed_num) 968{ 969 DPRINTF(LSQUnit, "Squashing until [sn:%lli]!" 970 "(Loads:%i Stores:%i)\n", squashed_num, loads, stores); 971 972 int load_idx = loadTail; 973 decrLdIdx(load_idx); 974 975 while (loads != 0 && loadQueue[load_idx]->seqNum > squashed_num) { 976 DPRINTF(LSQUnit,"Load Instruction PC %s squashed, " 977 "[sn:%lli]\n", 978 loadQueue[load_idx]->pcState(), 979 loadQueue[load_idx]->seqNum); 980 981 if (isStalled() && load_idx == stallingLoadIdx) { 982 stalled = false; 983 stallingStoreIsn = 0; 984 stallingLoadIdx = 0; 985 } 986 987 // Clear the smart pointer to make sure it is decremented. 988 loadQueue[load_idx]->setSquashed(); 989 loadQueue[load_idx] = NULL; 990 --loads; 991 992 // Inefficient! 993 loadTail = load_idx; 994 995 decrLdIdx(load_idx); 996 ++lsqSquashedLoads; 997 } 998 999 if (isLoadBlocked) { 1000 if (squashed_num < blockedLoadSeqNum) { 1001 isLoadBlocked = false; 1002 loadBlockedHandled = false; 1003 blockedLoadSeqNum = 0; 1004 } 1005 } 1006 1007 if (memDepViolator && squashed_num < memDepViolator->seqNum) { 1008 memDepViolator = NULL; 1009 } 1010 1011 int store_idx = storeTail; 1012 decrStIdx(store_idx); 1013 1014 while (stores != 0 && 1015 storeQueue[store_idx].inst->seqNum > squashed_num) { 1016 // Instructions marked as can WB are already committed. 1017 if (storeQueue[store_idx].canWB) { 1018 break; 1019 } 1020 1021 DPRINTF(LSQUnit,"Store Instruction PC %s squashed, " 1022 "idx:%i [sn:%lli]\n", 1023 storeQueue[store_idx].inst->pcState(), 1024 store_idx, storeQueue[store_idx].inst->seqNum); 1025 1026 // I don't think this can happen. It should have been cleared 1027 // by the stalling load. 1028 if (isStalled() && 1029 storeQueue[store_idx].inst->seqNum == stallingStoreIsn) { 1030 panic("Is stalled should have been cleared by stalling load!\n"); 1031 stalled = false; 1032 stallingStoreIsn = 0; 1033 } 1034 1035 // Clear the smart pointer to make sure it is decremented. 1036 storeQueue[store_idx].inst->setSquashed(); 1037 storeQueue[store_idx].inst = NULL; 1038 storeQueue[store_idx].canWB = 0; 1039 1040 // Must delete request now that it wasn't handed off to 1041 // memory. This is quite ugly. @todo: Figure out the proper 1042 // place to really handle request deletes. 1043 delete storeQueue[store_idx].req; 1044 if (TheISA::HasUnalignedMemAcc && storeQueue[store_idx].isSplit) { 1045 delete storeQueue[store_idx].sreqLow; 1046 delete storeQueue[store_idx].sreqHigh; 1047 1048 storeQueue[store_idx].sreqLow = NULL; 1049 storeQueue[store_idx].sreqHigh = NULL; 1050 } 1051 1052 storeQueue[store_idx].req = NULL; 1053 --stores; 1054 1055 // Inefficient! 1056 storeTail = store_idx; 1057 1058 decrStIdx(store_idx); 1059 ++lsqSquashedStores; 1060 } 1061} 1062 1063template <class Impl> 1064void 1065LSQUnit<Impl>::storePostSend(PacketPtr pkt) 1066{ 1067 if (isStalled() && 1068 storeQueue[storeWBIdx].inst->seqNum == stallingStoreIsn) { 1069 DPRINTF(LSQUnit, "Unstalling, stalling store [sn:%lli] " 1070 "load idx:%i\n", 1071 stallingStoreIsn, stallingLoadIdx); 1072 stalled = false; 1073 stallingStoreIsn = 0; 1074 iewStage->replayMemInst(loadQueue[stallingLoadIdx]); 1075 } 1076 1077 if (!storeQueue[storeWBIdx].inst->isStoreConditional()) { 1078 // The store is basically completed at this time. This 1079 // only works so long as the checker doesn't try to 1080 // verify the value in memory for stores. 1081 storeQueue[storeWBIdx].inst->setCompleted(); 1082 1083 if (cpu->checker) { 1084 cpu->checker->verify(storeQueue[storeWBIdx].inst); 1085 } 1086 } 1087 1088 if (needsTSO) { 1089 storeInFlight = true; 1090 } 1091 1092 incrStIdx(storeWBIdx); 1093} 1094 1095template <class Impl> 1096void 1097LSQUnit<Impl>::writeback(DynInstPtr &inst, PacketPtr pkt) 1098{ 1099 iewStage->wakeCPU(); 1100 1101 // Squashed instructions do not need to complete their access. 1102 if (inst->isSquashed()) { 1103 iewStage->decrWb(inst->seqNum); 1104 assert(!inst->isStore()); 1105 ++lsqIgnoredResponses; 1106 return; 1107 } 1108 1109 if (!inst->isExecuted()) { 1110 inst->setExecuted(); 1111 1112 // Complete access to copy data to proper place. 1113 inst->completeAcc(pkt); 1114 } 1115 1116 // Need to insert instruction into queue to commit 1117 iewStage->instToCommit(inst); 1118 1119 iewStage->activityThisCycle(); 1120 1121 // see if this load changed the PC 1122 iewStage->checkMisprediction(inst); 1123} 1124 1125template <class Impl> 1126void 1127LSQUnit<Impl>::completeStore(int store_idx) 1128{ 1129 assert(storeQueue[store_idx].inst); 1130 storeQueue[store_idx].completed = true; 1131 --storesToWB; 1132 // A bit conservative because a store completion may not free up entries, 1133 // but hopefully avoids two store completions in one cycle from making 1134 // the CPU tick twice. 1135 cpu->wakeCPU(); 1136 cpu->activityThisCycle(); 1137 1138 if (store_idx == storeHead) { 1139 do { 1140 incrStIdx(storeHead); 1141 1142 --stores; 1143 } while (storeQueue[storeHead].completed && 1144 storeHead != storeTail); 1145 1146 iewStage->updateLSQNextCycle = true; 1147 } 1148 1149 DPRINTF(LSQUnit, "Completing store [sn:%lli], idx:%i, store head " 1150 "idx:%i\n", 1151 storeQueue[store_idx].inst->seqNum, store_idx, storeHead); 1152 1153 if (isStalled() && 1154 storeQueue[store_idx].inst->seqNum == stallingStoreIsn) { 1155 DPRINTF(LSQUnit, "Unstalling, stalling store [sn:%lli] " 1156 "load idx:%i\n", 1157 stallingStoreIsn, stallingLoadIdx); 1158 stalled = false; 1159 stallingStoreIsn = 0; 1160 iewStage->replayMemInst(loadQueue[stallingLoadIdx]); 1161 } 1162 1163 storeQueue[store_idx].inst->setCompleted(); 1164 1165 if (needsTSO) { 1166 storeInFlight = false; 1167 } 1168 1169 // Tell the checker we've completed this instruction. Some stores 1170 // may get reported twice to the checker, but the checker can 1171 // handle that case. 1172 if (cpu->checker) { 1173 cpu->checker->verify(storeQueue[store_idx].inst); 1174 } 1175} 1176 1177template <class Impl> 1178bool 1179LSQUnit<Impl>::sendStore(PacketPtr data_pkt) 1180{ 1181 if (!dcachePort->sendTimingReq(data_pkt)) { 1182 // Need to handle becoming blocked on a store. 1183 isStoreBlocked = true; 1184 ++lsqCacheBlocked; 1185 assert(retryPkt == NULL); 1186 retryPkt = data_pkt; 1187 lsq->setRetryTid(lsqID); 1188 return false; 1189 } 1190 return true; 1191} 1192 1193template <class Impl> 1194void 1195LSQUnit<Impl>::recvRetry() 1196{ 1197 if (isStoreBlocked) { 1198 DPRINTF(LSQUnit, "Receiving retry: store blocked\n"); 1199 assert(retryPkt != NULL); 1200 1201 LSQSenderState *state = 1202 dynamic_cast<LSQSenderState *>(retryPkt->senderState); 1203 1204 if (dcachePort->sendTimingReq(retryPkt)) { 1205 // Don't finish the store unless this is the last packet. 1206 if (!TheISA::HasUnalignedMemAcc || !state->pktToSend || 1207 state->pendingPacket == retryPkt) { 1208 state->pktToSend = false; 1209 storePostSend(retryPkt); 1210 } 1211 retryPkt = NULL; 1212 isStoreBlocked = false; 1213 lsq->setRetryTid(InvalidThreadID); 1214 1215 // Send any outstanding packet. 1216 if (TheISA::HasUnalignedMemAcc && state->pktToSend) { 1217 assert(state->pendingPacket); 1218 if (sendStore(state->pendingPacket)) { 1219 storePostSend(state->pendingPacket); 1220 } 1221 } 1222 } else { 1223 // Still blocked! 1224 ++lsqCacheBlocked; 1225 lsq->setRetryTid(lsqID); 1226 } 1227 } else if (isLoadBlocked) { 1228 DPRINTF(LSQUnit, "Loads squash themselves and all younger insts, " 1229 "no need to resend packet.\n"); 1230 } else { 1231 DPRINTF(LSQUnit, "Retry received but LSQ is no longer blocked.\n"); 1232 } 1233} 1234 1235template <class Impl> 1236inline void 1237LSQUnit<Impl>::incrStIdx(int &store_idx) 1238{ 1239 if (++store_idx >= SQEntries) 1240 store_idx = 0; 1241} 1242 1243template <class Impl> 1244inline void 1245LSQUnit<Impl>::decrStIdx(int &store_idx) 1246{ 1247 if (--store_idx < 0) 1248 store_idx += SQEntries; 1249} 1250 1251template <class Impl> 1252inline void 1253LSQUnit<Impl>::incrLdIdx(int &load_idx) 1254{ 1255 if (++load_idx >= LQEntries) 1256 load_idx = 0; 1257} 1258 1259template <class Impl> 1260inline void 1261LSQUnit<Impl>::decrLdIdx(int &load_idx) 1262{ 1263 if (--load_idx < 0) 1264 load_idx += LQEntries; 1265} 1266 1267template <class Impl> 1268void 1269LSQUnit<Impl>::dumpInsts() 1270{ 1271 cprintf("Load store queue: Dumping instructions.\n"); 1272 cprintf("Load queue size: %i\n", loads); 1273 cprintf("Load queue: "); 1274 1275 int load_idx = loadHead; 1276 1277 while (load_idx != loadTail && loadQueue[load_idx]) { 1278 cprintf("%s ", loadQueue[load_idx]->pcState()); 1279 1280 incrLdIdx(load_idx); 1281 } 1282 1283 cprintf("Store queue size: %i\n", stores); 1284 cprintf("Store queue: "); 1285 1286 int store_idx = storeHead; 1287 1288 while (store_idx != storeTail && storeQueue[store_idx].inst) { 1289 cprintf("%s ", storeQueue[store_idx].inst->pcState()); 1290 1291 incrStIdx(store_idx); 1292 } 1293 1294 cprintf("\n"); 1295} 1296