diff options
Diffstat (limited to 'src/cpu/o3/lsq_unit.hh')
| -rw-r--r-- | src/cpu/o3/lsq_unit.hh | 201 |
1 files changed, 197 insertions, 4 deletions
diff --git a/src/cpu/o3/lsq_unit.hh b/src/cpu/o3/lsq_unit.hh index f5b60b2fc..d3dd34ee2 100644 --- a/src/cpu/o3/lsq_unit.hh +++ b/src/cpu/o3/lsq_unit.hh @@ -136,6 +136,12 @@ class LSQUnit { */ void checkSnoop(PacketPtr pkt); + // [InvisiSpec] check whether current request will hit in the + // spec buffer or not + int checkSpecBuffHit(const RequestPtr req, const int req_idx); + void setSpecBuffState(const RequestPtr req); + + bool checkPrevLoadsExecuted(const int req_idx); /** Executes a load instruction. */ Fault executeLoad(DynInstPtr &inst); @@ -154,6 +160,15 @@ class LSQUnit { /** Writes back stores. */ void writebackStores(); + /** [mengjia] Validate loads. */ + int exposeLoads(); + + /** [mengjia] Update Visbible State. + * In the mode defence relying on fence: setup fenceDelay state. + * In the mode defence relying on invisibleSpec: + * setup readyToExpose*/ + void updateVisibleState(); + /** Completes the data access that has been returned from the * memory system. */ void completeDataAccess(PacketPtr pkt); @@ -219,6 +234,8 @@ class LSQUnit { /** Returns the number of stores to writeback. */ int numStoresToWB() { return storesToWB; } + /** [InvisiSpec] Returns the number of loads to validate. */ + int numLoadsToVLD() { return loadsToVLD; } /** Returns if the LSQ unit will writeback on this cycle. */ bool willWB() { return storeQueue[storeWBIdx].canWB && @@ -235,18 +252,30 @@ class LSQUnit { /** Writes back the instruction, sending it to IEW. */ void writeback(DynInstPtr &inst, PacketPtr pkt); + // [InvisiSpec] complete Validates + void completeValidate(DynInstPtr &inst, PacketPtr pkt); + /** Writes back a store that couldn't be completed the previous cycle. */ void writebackPendingStore(); + /** Validates a load that couldn't be completed the previous cycle. */ + void validatePendingLoad(); + /** Handles completing the send of a store to memory. */ void storePostSend(PacketPtr pkt); + /** Handles completing the send of a validation to memory. */ + //void validationPostSend(PacketPtr pkt, int loadVLDIdx); + /** Completes the store at the specified index. */ void completeStore(int store_idx); /** Attempts to send a store to the cache. */ bool sendStore(PacketPtr data_pkt); + /** Attempts to send a validation to the cache. */ + //bool sendValidation(PacketPtr data_pkt, int loadVLDIdx); + /** Increments the given store index (circular queue). */ inline void incrStIdx(int &store_idx) const; /** Decrements the given store index (circular queue). */ @@ -409,6 +438,8 @@ class LSQUnit { /** The number of load instructions in the LQ. */ int loads; + /** [mengjia] The number of store instructions in the SQ waiting to writeback. */ + int loadsToVLD; /** The number of store instructions in the SQ. */ int stores; /** The number of store instructions in the SQ waiting to writeback. */ @@ -416,6 +447,10 @@ class LSQUnit { /** The index of the head instruction in the LQ. */ int loadHead; + /** [mengjia] The index of the first instruction that may be ready to be + * validated, and has not yet been validated. + */ + //int pendingLoadVLDIdx; /** The index of the tail instruction in the LQ. */ int loadTail; @@ -432,7 +467,7 @@ class LSQUnit { /** The number of cache ports available each cycle (stores only). */ int cacheStorePorts; - /** The number of used cache ports in this cycle by stores. */ + /** [InvisiSpec] The number of used cache ports in this cycle by stores. */ int usedStorePorts; //list<InstSeqNum> mshrSeqNums; @@ -458,6 +493,9 @@ class LSQUnit { /** Whehter or not a store is blocked due to the memory system. */ bool isStoreBlocked; + /** Whehter or not a validation is blocked due to the memory system. */ + bool isValidationBlocked; + /** Whether or not a store is in flight. */ bool storeInFlight; @@ -471,9 +509,21 @@ class LSQUnit { /** The packet that is pending free cache ports. */ PacketPtr pendingPkt; + /* [mengjia] define scheme variables */ + // Flag for whether issue packets in execution stage + bool loadInExec; + + // Flag for whether to use invisible speculative load + bool isInvisibleSpec; + /** Flag for memory model. */ bool needsTSO; + // Flag for whether defending against spectre attack or future attacks + bool isFuturistic; + bool allowSpecBuffHit; + /* [mengjia] different schemes determine values of 4 variables. */ + // Will also need how many read/write ports the Dcache has. Or keep track // of that in stage that is one level up, and only call executeLoad/Store // the appropriate number of times. @@ -508,6 +558,12 @@ class LSQUnit { /** Number of times the LSQ is blocked due to the cache. */ Stats::Scalar lsqCacheBlocked; + Stats::Scalar specBuffHits; + Stats::Scalar specBuffMisses; + Stats::Scalar numValidates; + Stats::Scalar numExposes; + Stats::Scalar numConvertedExposes; + public: /** Executes the load at the given index. */ Fault read(const RequestPtr &req, @@ -549,6 +605,8 @@ class LSQUnit { bool isStalled() { return stalled; } }; + +// IMPORTANT: the function to issue packets, interact with memory [mengjia] template <class Impl> Fault LSQUnit<Impl>::read(const RequestPtr &req, @@ -578,6 +636,7 @@ LSQUnit<Impl>::read(const RequestPtr &req, } // Check the SQ for any previous stores that might lead to forwarding + // why we have store queue index for a load operation? [mengjia] int store_idx = load_inst->sqIdx; int store_size = 0; @@ -587,6 +646,7 @@ LSQUnit<Impl>::read(const RequestPtr &req, load_idx, store_idx, storeHead, req->getPaddr(), sreqLow ? " split" : ""); + // LLSC: load-link/store-conditional [mengjia] if (req->isLLSC()) { assert(!sreqLow); // Disable recording the result temporarily. Writing to misc @@ -597,12 +657,14 @@ LSQUnit<Impl>::read(const RequestPtr &req, load_inst->recordResult(true); } + // request to memory mapped register [mengjia] if (req->isMmappedIpr()) { assert(!load_inst->memData); load_inst->memData = new uint8_t[64]; ThreadContext *thread = cpu->tcBase(lsqID); Cycles delay(0); + PacketPtr data_pkt = new Packet(req, MemCmd::ReadReq); data_pkt->dataStatic(load_inst->memData); @@ -750,6 +812,7 @@ LSQUnit<Impl>::read(const RequestPtr &req, DPRINTF(LSQUnit, "Doing memory access for inst [sn:%lli] PC %s\n", load_inst->seqNum, load_inst->pcState()); + // Allocate memory if this is the first time a load is issued. if (!load_inst->memData) { load_inst->memData = new uint8_t[req->getSize()]; @@ -757,10 +820,35 @@ LSQUnit<Impl>::read(const RequestPtr &req, // if we the cache is not blocked, do cache access bool completedFirst = false; - PacketPtr data_pkt = Packet::createRead(req); + + PacketPtr data_pkt = NULL; PacketPtr fst_data_pkt = NULL; PacketPtr snd_data_pkt = NULL; + // According to the isInsivisibleSpec variable to create + // corresponding type of packets [mengjia] + bool sendSpecRead = false; + if(isInvisibleSpec){ + if(!load_inst->readyToExpose()){ + assert(!req->isLLSC()); + assert(!req->isStrictlyOrdered()); + assert(!req->isMmappedIpr()); + sendSpecRead = true; + DPRINTF(LSQUnit, "send a spec read for inst [sn:%lli]\n", + load_inst->seqNum); + } + + } + + assert( !(sendSpecRead && load_inst->isSpecCompleted()) && + "Sending specRead twice for the same load insts"); + + if(sendSpecRead){ + data_pkt = Packet::createReadSpec(req); + }else{ + data_pkt = Packet::createRead(req); + } + data_pkt->dataStatic(load_inst->memData); LSQSenderState *state = new LSQSenderState; @@ -772,17 +860,64 @@ LSQUnit<Impl>::read(const RequestPtr &req, if (!TheISA::HasUnalignedMemAcc || !sreqLow) { // Point the first packet at the main data packet. fst_data_pkt = data_pkt; + + fst_data_pkt->setFirst(); + if (sendSpecRead){ + int src_idx = checkSpecBuffHit(req, load_idx); + if (src_idx != -1) { + if (allowSpecBuffHit){ + data_pkt->setOnlyAccessSpecBuff(); + } + data_pkt->srcIdx = src_idx; + specBuffHits++; + }else{ + specBuffMisses++; + } + } + fst_data_pkt->reqIdx = load_idx; } else { // Create the split packets. - fst_data_pkt = Packet::createRead(sreqLow); - snd_data_pkt = Packet::createRead(sreqHigh); + if(sendSpecRead){ + + fst_data_pkt = Packet::createReadSpec(sreqLow); + int fst_src_idx = checkSpecBuffHit(sreqLow, load_idx); + if ( fst_src_idx != -1 ) { + if (allowSpecBuffHit){ + fst_data_pkt->setOnlyAccessSpecBuff(); + } + fst_data_pkt->srcIdx = fst_src_idx; + specBuffHits++; + } else { + specBuffMisses++; + } + + snd_data_pkt = Packet::createReadSpec(sreqHigh); + int snd_src_idx = checkSpecBuffHit(sreqHigh, load_idx); + if ( snd_src_idx != -1 ) { + if (allowSpecBuffHit){ + snd_data_pkt->setOnlyAccessSpecBuff(); + } + snd_data_pkt->srcIdx = snd_src_idx; + specBuffHits++; + } else { + specBuffMisses++; + } + }else{ + fst_data_pkt = Packet::createRead(sreqLow); + snd_data_pkt = Packet::createRead(sreqHigh); + } + fst_data_pkt->setFirst(); fst_data_pkt->dataStatic(load_inst->memData); snd_data_pkt->dataStatic(load_inst->memData + sreqLow->getSize()); fst_data_pkt->senderState = state; snd_data_pkt->senderState = state; + fst_data_pkt->reqIdx = load_idx; + snd_data_pkt->reqIdx = load_idx; + fst_data_pkt->isSplit = true; + snd_data_pkt->isSplit = true; state->isSplit = true; state->outstanding = 2; state->mainPkt = data_pkt; @@ -794,6 +929,8 @@ LSQUnit<Impl>::read(const RequestPtr &req, // @todo We should account for cache port contention // and arbitrate between loads and stores. bool successful_load = true; + // MARK: here is the place memory request of read is sent [mengjia] + // [InvisiSpec] Sending out a memory request if (!dcachePort->sendTimingReq(fst_data_pkt)) { successful_load = false; } else if (TheISA::HasUnalignedMemAcc && sreqLow) { @@ -850,6 +987,62 @@ LSQUnit<Impl>::read(const RequestPtr &req, return NoFault; } + DPRINTF(LSQUnit, "successfully sent out packet(s) for inst [sn:%lli]\n", + load_inst->seqNum); + // Set everything ready for expose/validation after the read is + // successfully sent out + if(sendSpecRead){ // sending actual request + + // [mengjia] Here we set the needExposeOnly flag + if (needsTSO && !load_inst->isDataPrefetch()){ + // need to check whether previous load_instructions specComplete or not + if ( checkPrevLoadsExecuted(load_idx) ){ + load_inst->needExposeOnly(true); + DPRINTF(LSQUnit, "Set load PC %s, [sn:%lli] as " + "needExposeOnly\n", + load_inst->pcState(), load_inst->seqNum); + } else { + DPRINTF(LSQUnit, "Set load PC %s, [sn:%lli] as " + "needValidation\n", + load_inst->pcState(), load_inst->seqNum); + } + }else{ + //if RC, always only need expose + load_inst->needExposeOnly(true); + DPRINTF(LSQUnit, "Set load PC %s, [sn:%lli] as needExposeOnly\n", + load_inst->pcState(), load_inst->seqNum); + } + + load_inst->needPostFetch(true); + assert(!req->isMmappedIpr()); + //save expose requestPtr + if (TheISA::HasUnalignedMemAcc && sreqLow) { + load_inst->postSreqLow = std::make_shared<Request>(*sreqLow); + load_inst->postSreqHigh = std::make_shared<Request>(*sreqHigh); + load_inst->postReq = nullptr; + }else{ + load_inst->postReq = std::make_shared<Request>(*req); + load_inst->postSreqLow = nullptr; + load_inst->postSreqHigh = nullptr; + } + load_inst->needDeletePostReq(true); + DPRINTF(LSQUnit, "created validation/expose" + " request for inst [sn:%lli]" + "req=%#x, reqLow=%#x, reqHigh=%#x\n", + load_inst->seqNum, (Addr)(load_inst->postReq), + (Addr)(load_inst->postSreqLow), + (Addr)(load_inst->postSreqHigh)); + } else { + load_inst->setExposeCompleted(); + load_inst->needPostFetch(false); + if (TheISA::HasUnalignedMemAcc && sreqLow) { + setSpecBuffState(sreqLow); + setSpecBuffState(sreqHigh); + } else { + setSpecBuffState(req); + } + } + return NoFault; } |