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/*
* Copyright 2014 Google, Inc.
* Copyright (c) 2010-2013,2015,2017-2018, 2020-2021 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2002-2005 The Regents of The University of Michigan
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer;
* redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution;
* neither the name of the copyright holders nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "cpu/simple/timing.hh"
#include "arch/generic/decoder.hh"
#include "base/compiler.hh"
#include "cpu/exetrace.hh"
#include "debug/Config.hh"
#include "debug/Drain.hh"
#include "debug/ExecFaulting.hh"
#include "debug/HtmCpu.hh"
#include "debug/Mwait.hh"
#include "debug/SimpleCPU.hh"
#include "mem/packet.hh"
#include "mem/packet_access.hh"
#include "params/BaseTimingSimpleCPU.hh"
#include "sim/faults.hh"
#include "sim/full_system.hh"
#include "sim/system.hh"
namespace gem5
{
void
TimingSimpleCPU::init()
{
BaseSimpleCPU::init();
}
void
TimingSimpleCPU::TimingCPUPort::TickEvent::schedule(PacketPtr _pkt, Tick t)
{
pkt = _pkt;
cpu->schedule(this, t);
}
TimingSimpleCPU::TimingSimpleCPU(const BaseTimingSimpleCPUParams &p)
: BaseSimpleCPU(p), fetchTranslation(this), icachePort(this),
dcachePort(this), ifetch_pkt(NULL), dcache_pkt(NULL), previousCycle(0),
fetchEvent([this]{ fetch(); }, name())
{
_status = Idle;
}
TimingSimpleCPU::~TimingSimpleCPU()
{
}
DrainState
TimingSimpleCPU::drain()
{
// Deschedule any power gating event (if any)
deschedulePowerGatingEvent();
if (switchedOut())
return DrainState::Drained;
if (_status == Idle ||
(_status == BaseSimpleCPU::Running && isCpuDrained())) {
DPRINTF(Drain, "No need to drain.\n");
activeThreads.clear();
return DrainState::Drained;
} else {
DPRINTF(Drain, "Requesting drain.\n");
// The fetch event can become descheduled if a drain didn't
// succeed on the first attempt. We need to reschedule it if
// the CPU is waiting for a microcode routine to complete.
if (_status == BaseSimpleCPU::Running && !fetchEvent.scheduled())
schedule(fetchEvent, clockEdge());
return DrainState::Draining;
}
}
void
TimingSimpleCPU::drainResume()
{
assert(!fetchEvent.scheduled());
if (switchedOut())
return;
DPRINTF(SimpleCPU, "Resume\n");
verifyMemoryMode();
assert(!threadContexts.empty());
_status = BaseSimpleCPU::Idle;
for (ThreadID tid = 0; tid < numThreads; tid++) {
if (threadInfo[tid]->thread->status() == ThreadContext::Active) {
threadInfo[tid]->execContextStats.notIdleFraction = 1;
activeThreads.push_back(tid);
_status = BaseSimpleCPU::Running;
// Fetch if any threads active
if (!fetchEvent.scheduled()) {
schedule(fetchEvent, nextCycle());
}
} else {
threadInfo[tid]->execContextStats.notIdleFraction = 0;
}
}
// Reschedule any power gating event (if any)
schedulePowerGatingEvent();
}
bool
TimingSimpleCPU::tryCompleteDrain()
{
if (drainState() != DrainState::Draining)
return false;
DPRINTF(Drain, "tryCompleteDrain.\n");
if (!isCpuDrained())
return false;
DPRINTF(Drain, "CPU done draining, processing drain event\n");
signalDrainDone();
return true;
}
void
TimingSimpleCPU::switchOut()
{
SimpleExecContext& t_info = *threadInfo[curThread];
[[maybe_unused]] SimpleThread* thread = t_info.thread;
// hardware transactional memory
// Cannot switch out the CPU in the middle of a transaction
assert(!t_info.inHtmTransactionalState());
BaseSimpleCPU::switchOut();
assert(!fetchEvent.scheduled());
assert(_status == BaseSimpleCPU::Running || _status == Idle);
assert(!t_info.stayAtPC);
assert(thread->pcState().microPC() == 0);
updateCycleCounts();
updateCycleCounters(BaseCPU::CPU_STATE_ON);
}
void
TimingSimpleCPU::takeOverFrom(BaseCPU *oldCPU)
{
BaseSimpleCPU::takeOverFrom(oldCPU);
previousCycle = curCycle();
}
void
TimingSimpleCPU::verifyMemoryMode() const
{
if (!system->isTimingMode()) {
fatal("The timing CPU requires the memory system to be in "
"'timing' mode.\n");
}
}
void
TimingSimpleCPU::activateContext(ThreadID thread_num)
{
DPRINTF(SimpleCPU, "ActivateContext %d\n", thread_num);
assert(thread_num < numThreads);
threadInfo[thread_num]->execContextStats.notIdleFraction = 1;
if (_status == BaseSimpleCPU::Idle)
_status = BaseSimpleCPU::Running;
// kick things off by initiating the fetch of the next instruction
if (!fetchEvent.scheduled())
schedule(fetchEvent, clockEdge(Cycles(0)));
if (std::find(activeThreads.begin(), activeThreads.end(), thread_num)
== activeThreads.end()) {
activeThreads.push_back(thread_num);
}
BaseCPU::activateContext(thread_num);
}
void
TimingSimpleCPU::suspendContext(ThreadID thread_num)
{
DPRINTF(SimpleCPU, "SuspendContext %d\n", thread_num);
assert(thread_num < numThreads);
activeThreads.remove(thread_num);
// hardware transactional memory
// Cannot suspend context in the middle of a transaction.
assert(!threadInfo[curThread]->inHtmTransactionalState());
if (_status == Idle)
return;
assert(_status == BaseSimpleCPU::Running);
threadInfo[thread_num]->execContextStats.notIdleFraction = 0;
if (activeThreads.empty()) {
_status = Idle;
if (fetchEvent.scheduled()) {
deschedule(fetchEvent);
}
}
BaseCPU::suspendContext(thread_num);
}
bool
TimingSimpleCPU::handleReadPacket(PacketPtr pkt)
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
const RequestPtr &req = pkt->req;
// hardware transactional memory
// sanity check
if (req->isHTMCmd()) {
assert(!req->isLocalAccess());
}
// We're about the issues a locked load, so tell the monitor
// to start caring about this address
if (pkt->isRead() && pkt->req->isLLSC()) {
thread->getIsaPtr()->handleLockedRead(pkt->req);
}
if (req->isLocalAccess()) {
Cycles delay = req->localAccessor(thread->getTC(), pkt);
new IprEvent(pkt, this, clockEdge(delay));
_status = DcacheWaitResponse;
dcache_pkt = NULL;
} else if (!dcachePort.sendTimingReq(pkt)) {
_status = DcacheRetry;
dcache_pkt = pkt;
} else {
_status = DcacheWaitResponse;
// memory system takes ownership of packet
dcache_pkt = NULL;
}
return dcache_pkt == NULL;
}
void
TimingSimpleCPU::sendData(const RequestPtr &req, uint8_t *data, uint64_t *res,
bool read)
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
PacketPtr pkt = buildPacket(req, read);
pkt->dataDynamic<uint8_t>(data);
// hardware transactional memory
// If the core is in transactional mode or if the request is HtmCMD
// to abort a transaction, the packet should reflect that it is
// transactional and also contain a HtmUid for debugging.
const bool is_htm_speculative = t_info.inHtmTransactionalState();
if (is_htm_speculative || req->isHTMAbort()) {
pkt->setHtmTransactional(t_info.getHtmTransactionUid());
}
if (req->isHTMAbort())
DPRINTF(HtmCpu, "htmabort htmUid=%u\n", t_info.getHtmTransactionUid());
if (req->getFlags().isSet(Request::NO_ACCESS)) {
assert(!dcache_pkt);
pkt->makeResponse();
completeDataAccess(pkt);
} else if (read) {
handleReadPacket(pkt);
} else {
bool do_access = true; // flag to suppress cache access
if (req->isLLSC()) {
do_access = thread->getIsaPtr()->handleLockedWrite(
req, dcachePort.cacheBlockMask);
} else if (req->isCondSwap()) {
assert(res);
req->setExtraData(*res);
}
if (do_access) {
dcache_pkt = pkt;
handleWritePacket();
threadSnoop(pkt, curThread);
} else {
_status = DcacheWaitResponse;
completeDataAccess(pkt);
}
}
}
void
TimingSimpleCPU::sendSplitData(const RequestPtr &req1, const RequestPtr &req2,
const RequestPtr &req, uint8_t *data, bool read)
{
SimpleExecContext &t_info = *threadInfo[curThread];
PacketPtr pkt1, pkt2;
buildSplitPacket(pkt1, pkt2, req1, req2, req, data, read);
// hardware transactional memory
// HTM commands should never use SplitData
assert(!req1->isHTMCmd() && !req2->isHTMCmd());
// If the thread is executing transactionally,
// reflect this in the packets.
if (t_info.inHtmTransactionalState()) {
pkt1->setHtmTransactional(t_info.getHtmTransactionUid());
pkt2->setHtmTransactional(t_info.getHtmTransactionUid());
}
if (req->getFlags().isSet(Request::NO_ACCESS)) {
assert(!dcache_pkt);
pkt1->makeResponse();
completeDataAccess(pkt1);
} else if (read) {
SplitFragmentSenderState * send_state =
dynamic_cast<SplitFragmentSenderState *>(pkt1->senderState);
if (handleReadPacket(pkt1)) {
send_state->clearFromParent();
send_state = dynamic_cast<SplitFragmentSenderState *>(
pkt2->senderState);
if (handleReadPacket(pkt2)) {
send_state->clearFromParent();
}
}
} else {
dcache_pkt = pkt1;
SplitFragmentSenderState * send_state =
dynamic_cast<SplitFragmentSenderState *>(pkt1->senderState);
if (handleWritePacket()) {
send_state->clearFromParent();
dcache_pkt = pkt2;
send_state = dynamic_cast<SplitFragmentSenderState *>(
pkt2->senderState);
if (handleWritePacket()) {
send_state->clearFromParent();
}
}
}
}
void
TimingSimpleCPU::translationFault(const Fault &fault)
{
// fault may be NoFault in cases where a fault is suppressed,
// for instance prefetches.
updateCycleCounts();
updateCycleCounters(BaseCPU::CPU_STATE_ON);
if ((fault != NoFault) && traceData) {
traceFault();
}
postExecute();
advanceInst(fault);
}
PacketPtr
TimingSimpleCPU::buildPacket(const RequestPtr &req, bool read)
{
return read ? Packet::createRead(req) : Packet::createWrite(req);
}
void
TimingSimpleCPU::buildSplitPacket(PacketPtr &pkt1, PacketPtr &pkt2,
const RequestPtr &req1, const RequestPtr &req2, const RequestPtr &req,
uint8_t *data, bool read)
{
pkt1 = pkt2 = NULL;
assert(!req1->isLocalAccess() && !req2->isLocalAccess());
if (req->getFlags().isSet(Request::NO_ACCESS)) {
pkt1 = buildPacket(req, read);
return;
}
pkt1 = buildPacket(req1, read);
pkt2 = buildPacket(req2, read);
PacketPtr pkt = new Packet(req, pkt1->cmd.responseCommand());
pkt->dataDynamic<uint8_t>(data);
pkt1->dataStatic<uint8_t>(data);
pkt2->dataStatic<uint8_t>(data + req1->getSize());
SplitMainSenderState * main_send_state = new SplitMainSenderState;
pkt->senderState = main_send_state;
main_send_state->fragments[0] = pkt1;
main_send_state->fragments[1] = pkt2;
main_send_state->outstanding = 2;
pkt1->senderState = new SplitFragmentSenderState(pkt, 0);
pkt2->senderState = new SplitFragmentSenderState(pkt, 1);
}
Fault
TimingSimpleCPU::initiateMemRead(Addr addr, unsigned size,
Request::Flags flags,
const std::vector<bool>& byte_enable)
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
Fault fault;
const Addr pc = thread->pcState().instAddr();
unsigned block_size = cacheLineSize();
BaseMMU::Mode mode = BaseMMU::Read;
if (traceData)
traceData->setMem(addr, size, flags);
RequestPtr req = std::make_shared<Request>(
addr, size, flags, dataRequestorId(), pc, thread->contextId());
req->setByteEnable(byte_enable);
req->taskId(taskId());
Addr split_addr = roundDown(addr + size - 1, block_size);
assert(split_addr <= addr || split_addr - addr < block_size);
_status = DTBWaitResponse;
if (split_addr > addr) {
RequestPtr req1, req2;
assert(!req->isLLSC() && !req->isSwap());
req->splitOnVaddr(split_addr, req1, req2);
WholeTranslationState *state =
new WholeTranslationState(req, req1, req2, new uint8_t[size],
NULL, mode);
DataTranslation<TimingSimpleCPU *> *trans1 =
new DataTranslation<TimingSimpleCPU *>(this, state, 0);
DataTranslation<TimingSimpleCPU *> *trans2 =
new DataTranslation<TimingSimpleCPU *>(this, state, 1);
thread->mmu->translateTiming(req1, thread->getTC(), trans1, mode);
thread->mmu->translateTiming(req2, thread->getTC(), trans2, mode);
} else {
WholeTranslationState *state =
new WholeTranslationState(req, new uint8_t[size], NULL, mode);
DataTranslation<TimingSimpleCPU *> *translation
= new DataTranslation<TimingSimpleCPU *>(this, state);
thread->mmu->translateTiming(req, thread->getTC(), translation, mode);
}
return NoFault;
}
bool
TimingSimpleCPU::handleWritePacket()
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
const RequestPtr &req = dcache_pkt->req;
if (req->isLocalAccess()) {
Cycles delay = req->localAccessor(thread->getTC(), dcache_pkt);
new IprEvent(dcache_pkt, this, clockEdge(delay));
_status = DcacheWaitResponse;
dcache_pkt = NULL;
} else if (!dcachePort.sendTimingReq(dcache_pkt)) {
_status = DcacheRetry;
} else {
_status = DcacheWaitResponse;
// memory system takes ownership of packet
dcache_pkt = NULL;
}
return dcache_pkt == NULL;
}
Fault
TimingSimpleCPU::writeMem(uint8_t *data, unsigned size,
Addr addr, Request::Flags flags, uint64_t *res,
const std::vector<bool>& byte_enable)
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
uint8_t *newData = new uint8_t[size];
const Addr pc = thread->pcState().instAddr();
unsigned block_size = cacheLineSize();
BaseMMU::Mode mode = BaseMMU::Write;
if (data == NULL) {
assert(flags & Request::STORE_NO_DATA);
// This must be a cache block cleaning request
memset(newData, 0, size);
} else {
memcpy(newData, data, size);
}
if (traceData)
traceData->setMem(addr, size, flags);
RequestPtr req = std::make_shared<Request>(
addr, size, flags, dataRequestorId(), pc, thread->contextId());
req->setByteEnable(byte_enable);
req->taskId(taskId());
Addr split_addr = roundDown(addr + size - 1, block_size);
assert(split_addr <= addr || split_addr - addr < block_size);
_status = DTBWaitResponse;
// TODO: TimingSimpleCPU doesn't support arbitrarily long multi-line mem.
// accesses yet
if (split_addr > addr) {
RequestPtr req1, req2;
assert(!req->isLLSC() && !req->isSwap());
req->splitOnVaddr(split_addr, req1, req2);
WholeTranslationState *state =
new WholeTranslationState(req, req1, req2, newData, res, mode);
DataTranslation<TimingSimpleCPU *> *trans1 =
new DataTranslation<TimingSimpleCPU *>(this, state, 0);
DataTranslation<TimingSimpleCPU *> *trans2 =
new DataTranslation<TimingSimpleCPU *>(this, state, 1);
thread->mmu->translateTiming(req1, thread->getTC(), trans1, mode);
thread->mmu->translateTiming(req2, thread->getTC(), trans2, mode);
} else {
WholeTranslationState *state =
new WholeTranslationState(req, newData, res, mode);
DataTranslation<TimingSimpleCPU *> *translation =
new DataTranslation<TimingSimpleCPU *>(this, state);
thread->mmu->translateTiming(req, thread->getTC(), translation, mode);
}
// Translation faults will be returned via finishTranslation()
return NoFault;
}
Fault
TimingSimpleCPU::initiateMemAMO(Addr addr, unsigned size,
Request::Flags flags,
AtomicOpFunctorPtr amo_op)
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
Fault fault;
const Addr pc = thread->pcState().instAddr();
unsigned block_size = cacheLineSize();
BaseMMU::Mode mode = BaseMMU::Write;
if (traceData)
traceData->setMem(addr, size, flags);
RequestPtr req = std::make_shared<Request>(addr, size, flags,
dataRequestorId(), pc, thread->contextId(),
std::move(amo_op));
assert(req->hasAtomicOpFunctor());
req->taskId(taskId());
Addr split_addr = roundDown(addr + size - 1, block_size);
// AMO requests that access across a cache line boundary are not
// allowed since the cache does not guarantee AMO ops to be executed
// atomically in two cache lines
// For ISAs such as x86 that requires AMO operations to work on
// accesses that cross cache-line boundaries, the cache needs to be
// modified to support locking both cache lines to guarantee the
// atomicity.
if (split_addr > addr) {
panic("AMO requests should not access across a cache line boundary\n");
}
_status = DTBWaitResponse;
WholeTranslationState *state =
new WholeTranslationState(req, new uint8_t[size], NULL, mode);
DataTranslation<TimingSimpleCPU *> *translation
= new DataTranslation<TimingSimpleCPU *>(this, state);
thread->mmu->translateTiming(req, thread->getTC(), translation, mode);
return NoFault;
}
void
TimingSimpleCPU::threadSnoop(PacketPtr pkt, ThreadID sender)
{
for (ThreadID tid = 0; tid < numThreads; tid++) {
if (tid != sender) {
if (getCpuAddrMonitor(tid)->doMonitor(pkt)) {
wakeup(tid);
}
threadInfo[tid]->thread->getIsaPtr()->handleLockedSnoop(pkt,
dcachePort.cacheBlockMask);
}
}
}
void
TimingSimpleCPU::finishTranslation(WholeTranslationState *state)
{
_status = BaseSimpleCPU::Running;
if (state->getFault() != NoFault) {
if (state->isPrefetch()) {
state->setNoFault();
}
delete [] state->data;
state->deleteReqs();
translationFault(state->getFault());
} else {
if (!state->isSplit) {
sendData(state->mainReq, state->data, state->res,
state->mode == BaseMMU::Read);
} else {
sendSplitData(state->sreqLow, state->sreqHigh, state->mainReq,
state->data, state->mode == BaseMMU::Read);
}
}
delete state;
}
void
TimingSimpleCPU::fetch()
{
// Change thread if multi-threaded
swapActiveThread();
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
DPRINTF(SimpleCPU, "Fetch\n");
if (!curStaticInst || !curStaticInst->isDelayedCommit()) {
checkForInterrupts();
checkPcEventQueue();
}
// We must have just got suspended by a PC event
if (_status == Idle)
return;
MicroPC upc = thread->pcState().microPC();
bool needToFetch = !isRomMicroPC(upc) && !curMacroStaticInst;
if (needToFetch) {
_status = BaseSimpleCPU::Running;
RequestPtr ifetch_req = std::make_shared<Request>();
ifetch_req->taskId(taskId());
ifetch_req->setContext(thread->contextId());
setupFetchRequest(ifetch_req);
DPRINTF(SimpleCPU, "Translating address %#x\n", ifetch_req->getVaddr());
thread->mmu->translateTiming(ifetch_req, thread->getTC(),
&fetchTranslation, BaseMMU::Execute);
} else {
_status = IcacheWaitResponse;
completeIfetch(NULL);
updateCycleCounts();
updateCycleCounters(BaseCPU::CPU_STATE_ON);
}
}
void
TimingSimpleCPU::sendFetch(const Fault &fault, const RequestPtr &req,
ThreadContext *tc)
{
auto &decoder = threadInfo[curThread]->thread->decoder;
if (fault == NoFault) {
DPRINTF(SimpleCPU, "Sending fetch for addr %#x(pa: %#x)\n",
req->getVaddr(), req->getPaddr());
ifetch_pkt = new Packet(req, MemCmd::ReadReq);
ifetch_pkt->dataStatic(decoder->moreBytesPtr());
DPRINTF(SimpleCPU, " -- pkt addr: %#x\n", ifetch_pkt->getAddr());
if (!icachePort.sendTimingReq(ifetch_pkt)) {
// Need to wait for retry
_status = IcacheRetry;
} else {
// Need to wait for cache to respond
_status = IcacheWaitResponse;
// ownership of packet transferred to memory system
ifetch_pkt = NULL;
}
} else {
DPRINTF(SimpleCPU, "Translation of addr %#x faulted\n", req->getVaddr());
// fetch fault: advance directly to next instruction (fault handler)
_status = BaseSimpleCPU::Running;
advanceInst(fault);
}
updateCycleCounts();
updateCycleCounters(BaseCPU::CPU_STATE_ON);
}
void
TimingSimpleCPU::advanceInst(const Fault &fault)
{
SimpleExecContext &t_info = *threadInfo[curThread];
if (_status == Faulting)
return;
if (fault != NoFault) {
// hardware transactional memory
// If a fault occurred within a transaction
// ensure that the transaction aborts
if (t_info.inHtmTransactionalState() &&
!std::dynamic_pointer_cast<GenericHtmFailureFault>(fault)) {
DPRINTF(HtmCpu, "fault (%s) occurred - "
"replacing with HTM abort fault htmUid=%u\n",
fault->name(), t_info.getHtmTransactionUid());
Fault tmfault = std::make_shared<GenericHtmFailureFault>(
t_info.getHtmTransactionUid(),
HtmFailureFaultCause::EXCEPTION);
advancePC(tmfault);
reschedule(fetchEvent, clockEdge(), true);
_status = Faulting;
return;
}
DPRINTF(SimpleCPU, "Fault occured. Handling the fault\n");
advancePC(fault);
// A syscall fault could suspend this CPU (e.g., futex_wait)
// If the _status is not Idle, schedule an event to fetch the next
// instruction after 'stall' ticks.
// If the cpu has been suspended (i.e., _status == Idle), another
// cpu will wake this cpu up later.
if (_status != Idle) {
DPRINTF(SimpleCPU, "Scheduling fetch event after the Fault\n");
Tick stall = std::dynamic_pointer_cast<SyscallRetryFault>(fault) ?
clockEdge(syscallRetryLatency) : clockEdge();
reschedule(fetchEvent, stall, true);
_status = Faulting;
}
return;
}
if (!t_info.stayAtPC)
advancePC(fault);
if (tryCompleteDrain())
return;
serviceInstCountEvents();
if (_status == BaseSimpleCPU::Running) {
// kick off fetch of next instruction... callback from icache
// response will cause that instruction to be executed,
// keeping the CPU running.
fetch();
}
}
void
TimingSimpleCPU::completeIfetch(PacketPtr pkt)
{
SimpleExecContext& t_info = *threadInfo[curThread];
DPRINTF(SimpleCPU, "Complete ICache Fetch for addr %#x\n", pkt ?
pkt->getAddr() : 0);
// received a response from the icache: execute the received
// instruction
panic_if(pkt && pkt->isError(), "Instruction fetch (%s) failed: %s",
pkt->getAddrRange().to_string(), pkt->print());
assert(_status == IcacheWaitResponse);
_status = BaseSimpleCPU::Running;
updateCycleCounts();
updateCycleCounters(BaseCPU::CPU_STATE_ON);
if (pkt)
pkt->req->setAccessLatency();
preExecute();
// hardware transactional memory
if (curStaticInst && curStaticInst->isHtmStart()) {
// if this HtmStart is not within a transaction,
// then assign it a new htmTransactionUid
if (!t_info.inHtmTransactionalState())
t_info.newHtmTransactionUid();
SimpleThread* thread = t_info.thread;
thread->htmTransactionStarts++;
DPRINTF(HtmCpu, "htmTransactionStarts++=%u\n",
thread->htmTransactionStarts);
}
if (curStaticInst && curStaticInst->isMemRef()) {
// load or store: just send to dcache
Fault fault = curStaticInst->initiateAcc(&t_info, traceData);
// If we're not running now the instruction will complete in a dcache
// response callback or the instruction faulted and has started an
// ifetch
if (_status == BaseSimpleCPU::Running) {
if (fault != NoFault && traceData) {
traceFault();
}
postExecute();
// @todo remove me after debugging with legion done
if (curStaticInst && (!curStaticInst->isMicroop() ||
curStaticInst->isFirstMicroop()))
instCnt++;
advanceInst(fault);
}
} else if (curStaticInst) {
// non-memory instruction: execute completely now
Fault fault = curStaticInst->execute(&t_info, traceData);
// keep an instruction count
if (fault == NoFault)
countInst();
else if (traceData) {
traceFault();
}
postExecute();
// @todo remove me after debugging with legion done
if (curStaticInst && (!curStaticInst->isMicroop() ||
curStaticInst->isFirstMicroop()))
instCnt++;
advanceInst(fault);
} else {
advanceInst(NoFault);
}
if (pkt) {
delete pkt;
}
}
void
TimingSimpleCPU::IcachePort::ITickEvent::process()
{
cpu->completeIfetch(pkt);
}
bool
TimingSimpleCPU::IcachePort::recvTimingResp(PacketPtr pkt)
{
DPRINTF(SimpleCPU, "Received fetch response %#x\n", pkt->getAddr());
// hardware transactional memory
// Currently, there is no support for tracking instruction fetches
// in an transaction's read set.
if (pkt->htmTransactionFailedInCache()) {
panic("HTM transactional support for"
" instruction stream not yet supported\n");
}
// we should only ever see one response per cycle since we only
// issue a new request once this response is sunk
assert(!tickEvent.scheduled());
// delay processing of returned data until next CPU clock edge
tickEvent.schedule(pkt, cpu->clockEdge());
return true;
}
void
TimingSimpleCPU::IcachePort::recvReqRetry()
{
// we shouldn't get a retry unless we have a packet that we're
// waiting to transmit
assert(cpu->ifetch_pkt != NULL);
assert(cpu->_status == IcacheRetry);
PacketPtr tmp = cpu->ifetch_pkt;
if (sendTimingReq(tmp)) {
cpu->_status = IcacheWaitResponse;
cpu->ifetch_pkt = NULL;
}
}
void
TimingSimpleCPU::completeDataAccess(PacketPtr pkt)
{
// hardware transactional memory
SimpleExecContext *t_info = threadInfo[curThread];
[[maybe_unused]] const bool is_htm_speculative =
t_info->inHtmTransactionalState();
// received a response from the dcache: complete the load or store
// instruction
panic_if(pkt->isError(), "Data access (%s) failed: %s",
pkt->getAddrRange().to_string(), pkt->print());
assert(_status == DcacheWaitResponse || _status == DTBWaitResponse ||
pkt->req->getFlags().isSet(Request::NO_ACCESS));
pkt->req->setAccessLatency();
updateCycleCounts();
updateCycleCounters(BaseCPU::CPU_STATE_ON);
if (pkt->senderState) {
// hardware transactional memory
// There shouldn't be HtmCmds occurring in multipacket requests
if (pkt->req->isHTMCmd()) {
panic("unexpected HTM case");
}
SplitFragmentSenderState * send_state =
dynamic_cast<SplitFragmentSenderState *>(pkt->senderState);
assert(send_state);
PacketPtr big_pkt = send_state->bigPkt;
delete send_state;
if (pkt->isHtmTransactional()) {
assert(is_htm_speculative);
big_pkt->setHtmTransactional(
pkt->getHtmTransactionUid()
);
}
if (pkt->htmTransactionFailedInCache()) {
assert(is_htm_speculative);
big_pkt->setHtmTransactionFailedInCache(
pkt->getHtmTransactionFailedInCacheRC()
);
}
delete pkt;
SplitMainSenderState * main_send_state =
dynamic_cast<SplitMainSenderState *>(big_pkt->senderState);
assert(main_send_state);
// Record the fact that this packet is no longer outstanding.
assert(main_send_state->outstanding != 0);
main_send_state->outstanding--;
if (main_send_state->outstanding) {
return;
} else {
delete main_send_state;
big_pkt->senderState = NULL;
pkt = big_pkt;
}
}
_status = BaseSimpleCPU::Running;
Fault fault;
// hardware transactional memory
// sanity checks
// ensure htmTransactionUids are equivalent
if (pkt->isHtmTransactional())
assert (pkt->getHtmTransactionUid() ==
t_info->getHtmTransactionUid());
// can't have a packet that fails a transaction while not in a transaction
if (pkt->htmTransactionFailedInCache())
assert(is_htm_speculative);
// shouldn't fail through stores because this would be inconsistent w/ O3
// which cannot fault after the store has been sent to memory
if (pkt->htmTransactionFailedInCache() && !pkt->isWrite()) {
const HtmCacheFailure htm_rc =
pkt->getHtmTransactionFailedInCacheRC();
DPRINTF(HtmCpu, "HTM abortion in cache (rc=%s) detected htmUid=%u\n",
htmFailureToStr(htm_rc), pkt->getHtmTransactionUid());
// Currently there are only two reasons why a transaction would
// fail in the memory subsystem--
// (1) A transactional line was evicted from the cache for
// space (or replacement policy) reasons.
// (2) Another core/device requested a cache line that is in this
// transaction's read/write set that is incompatible with the
// HTM's semantics, e.g. another core requesting exclusive access
// of a line in this core's read set.
if (htm_rc == HtmCacheFailure::FAIL_SELF) {
fault = std::make_shared<GenericHtmFailureFault>(
t_info->getHtmTransactionUid(),
HtmFailureFaultCause::SIZE);
} else if (htm_rc == HtmCacheFailure::FAIL_REMOTE) {
fault = std::make_shared<GenericHtmFailureFault>(
t_info->getHtmTransactionUid(),
HtmFailureFaultCause::MEMORY);
} else {
panic("HTM - unhandled rc %s", htmFailureToStr(htm_rc));
}
} else {
fault = curStaticInst->completeAcc(pkt, t_info,
traceData);
}
// hardware transactional memory
// Track HtmStop instructions,
// e.g. instructions which commit a transaction.
if (curStaticInst && curStaticInst->isHtmStop()) {
t_info->thread->htmTransactionStops++;
DPRINTF(HtmCpu, "htmTransactionStops++=%u\n",
t_info->thread->htmTransactionStops);
}
// keep an instruction count
if (fault == NoFault)
countInst();
else if (traceData) {
traceFault();
}
delete pkt;
postExecute();
advanceInst(fault);
}
void
TimingSimpleCPU::updateCycleCounts()
{
const Cycles delta(curCycle() - previousCycle);
baseStats.numCycles += delta;
previousCycle = curCycle();
}
void
TimingSimpleCPU::DcachePort::recvTimingSnoopReq(PacketPtr pkt)
{
for (ThreadID tid = 0; tid < cpu->numThreads; tid++) {
if (cpu->getCpuAddrMonitor(tid)->doMonitor(pkt)) {
cpu->wakeup(tid);
}
}
// Making it uniform across all CPUs:
// The CPUs need to be woken up only on an invalidation packet
// (when using caches) or on an incoming write packet (when not
// using caches) It is not necessary to wake up the processor on
// all incoming packets
if (pkt->isInvalidate() || pkt->isWrite()) {
for (auto &t_info : cpu->threadInfo) {
t_info->thread->getIsaPtr()->handleLockedSnoop(pkt,
cacheBlockMask);
}
} else if (pkt->req && pkt->req->isTlbiExtSync()) {
// We received a TLBI_EXT_SYNC request.
// In a detailed sim we would wait for memory ops to complete,
// but in our simple case we just respond immediately
auto reply_req = Request::createMemManagement(
Request::TLBI_EXT_SYNC_COMP,
cpu->dataRequestorId());
// Extra Data = the transaction ID of the Sync we're completing
reply_req->setExtraData(pkt->req->getExtraData());
PacketPtr reply_pkt = Packet::createRead(reply_req);
// TODO - reserve some credit for these responses?
if (!sendTimingReq(reply_pkt)) {
panic("Couldn't send TLBI_EXT_SYNC_COMP message");
}
}
}
void
TimingSimpleCPU::DcachePort::recvFunctionalSnoop(PacketPtr pkt)
{
for (ThreadID tid = 0; tid < cpu->numThreads; tid++) {
if (cpu->getCpuAddrMonitor(tid)->doMonitor(pkt)) {
cpu->wakeup(tid);
}
}
}
bool
TimingSimpleCPU::DcachePort::recvTimingResp(PacketPtr pkt)
{
DPRINTF(SimpleCPU, "Received load/store response %#x\n", pkt->getAddr());
// The timing CPU is not really ticked, instead it relies on the
// memory system (fetch and load/store) to set the pace.
if (!tickEvent.scheduled()) {
// Delay processing of returned data until next CPU clock edge
tickEvent.schedule(pkt, cpu->clockEdge());
return true;
} else {
// In the case of a split transaction and a cache that is
// faster than a CPU we could get two responses in the
// same tick, delay the second one
if (!retryRespEvent.scheduled())
cpu->schedule(retryRespEvent, cpu->clockEdge(Cycles(1)));
return false;
}
}
void
TimingSimpleCPU::DcachePort::DTickEvent::process()
{
cpu->completeDataAccess(pkt);
}
void
TimingSimpleCPU::DcachePort::recvReqRetry()
{
// we shouldn't get a retry unless we have a packet that we're
// waiting to transmit
assert(cpu->dcache_pkt != NULL);
assert(cpu->_status == DcacheRetry);
PacketPtr tmp = cpu->dcache_pkt;
if (tmp->senderState) {
// This is a packet from a split access.
SplitFragmentSenderState * send_state =
dynamic_cast<SplitFragmentSenderState *>(tmp->senderState);
assert(send_state);
PacketPtr big_pkt = send_state->bigPkt;
SplitMainSenderState * main_send_state =
dynamic_cast<SplitMainSenderState *>(big_pkt->senderState);
assert(main_send_state);
if (sendTimingReq(tmp)) {
// If we were able to send without retrying, record that fact
// and try sending the other fragment.
send_state->clearFromParent();
int other_index = main_send_state->getPendingFragment();
if (other_index > 0) {
tmp = main_send_state->fragments[other_index];
cpu->dcache_pkt = tmp;
if ((big_pkt->isRead() && cpu->handleReadPacket(tmp)) ||
(big_pkt->isWrite() && cpu->handleWritePacket())) {
main_send_state->fragments[other_index] = NULL;
}
} else {
cpu->_status = DcacheWaitResponse;
// memory system takes ownership of packet
cpu->dcache_pkt = NULL;
}
}
} else if (sendTimingReq(tmp)) {
cpu->_status = DcacheWaitResponse;
// memory system takes ownership of packet
cpu->dcache_pkt = NULL;
}
}
TimingSimpleCPU::IprEvent::IprEvent(Packet *_pkt, TimingSimpleCPU *_cpu,
Tick t)
: pkt(_pkt), cpu(_cpu)
{
cpu->schedule(this, t);
}
void
TimingSimpleCPU::IprEvent::process()
{
cpu->completeDataAccess(pkt);
}
const char *
TimingSimpleCPU::IprEvent::description() const
{
return "Timing Simple CPU Delay IPR event";
}
void
TimingSimpleCPU::printAddr(Addr a)
{
dcachePort.printAddr(a);
}
Fault
TimingSimpleCPU::initiateMemMgmtCmd(Request::Flags flags)
{
SimpleExecContext &t_info = *threadInfo[curThread];
SimpleThread* thread = t_info.thread;
const Addr addr = 0x0ul;
const Addr pc = thread->pcState().instAddr();
const int size = 8;
if (traceData)
traceData->setMem(addr, size, flags);
RequestPtr req = std::make_shared<Request>(
addr, size, flags, dataRequestorId());
req->setPC(pc);
req->setContext(thread->contextId());
req->taskId(taskId());
req->setInstCount(t_info.numInst);
assert(req->isHTMCmd() || req->isTlbiCmd());
// Use the payload as a sanity check,
// the memory subsystem will clear allocated data
uint8_t *data = new uint8_t[size];
assert(data);
uint64_t rc = 0xdeadbeeflu;
memcpy (data, &rc, size);
// debugging output
if (req->isHTMCmd()) {
if (req->isHTMStart())
DPRINTF(HtmCpu, "HTMstart htmUid=%u\n",
t_info.getHtmTransactionUid());
else if (req->isHTMCommit())
DPRINTF(HtmCpu, "HTMcommit htmUid=%u\n",
t_info.getHtmTransactionUid());
else if (req->isHTMCancel())
DPRINTF(HtmCpu, "HTMcancel htmUid=%u\n",
t_info.getHtmTransactionUid());
else
panic("initiateMemMgmtCmd: unknown HTM CMD");
}
sendData(req, data, nullptr, true);
return NoFault;
}
void
TimingSimpleCPU::htmSendAbortSignal(ThreadID tid, uint64_t htm_uid,
HtmFailureFaultCause cause)
{
SimpleExecContext& t_info = *threadInfo[tid];
SimpleThread* thread = t_info.thread;
const Addr addr = 0x0ul;
const Addr pc = thread->pcState().instAddr();
const int size = 8;
const Request::Flags flags =
Request::PHYSICAL|Request::STRICT_ORDER|Request::HTM_ABORT;
if (traceData)
traceData->setMem(addr, size, flags);
// notify l1 d-cache (ruby) that core has aborted transaction
RequestPtr req = std::make_shared<Request>(
addr, size, flags, dataRequestorId());
req->setPC(pc);
req->setContext(thread->contextId());
req->taskId(taskId());
req->setInstCount(t_info.numInst);
req->setHtmAbortCause(cause);
assert(req->isHTMAbort());
uint8_t *data = new uint8_t[size];
assert(data);
uint64_t rc = 0lu;
memcpy (data, &rc, size);
sendData(req, data, nullptr, true);
}
} // namespace gem5