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/*
* Copyright (c) 2014 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
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* 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
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*
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* met: redistributions of source code must retain the above copyright
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* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "mem/mem_checker.hh"
#include "base/logging.hh"
namespace gem5
{
void
MemChecker::WriteCluster::startWrite(MemChecker::Serial serial, Tick _start,
uint8_t data)
{
assert(!isComplete());
if (start == TICK_FUTURE) {
// Initialize a fresh write cluster
start = _start;
}
chatty_assert(start <= _start, "WriteClusters must filled in order!");
++numIncomplete;
if (complete != TICK_FUTURE) {
// Reopen a closed write cluster
assert(_start < complete); // Should open a new write cluster instead
// Also somewhat fishy wrt causality / ordering of calls vs time
// progression TODO: Check me!
complete = TICK_FUTURE;
}
// Create new transaction, and denote completion time to be in the future.
writes.insert(std::make_pair(serial,
MemChecker::Transaction(serial, _start, TICK_FUTURE, data)));
}
void
MemChecker::WriteCluster::completeWrite(MemChecker::Serial serial,
Tick _complete)
{
auto it = writes.find(serial);
if (it == writes.end()) {
warn("Could not locate write transaction: serial = %d, "
"complete = %d\n", serial, _complete);
return;
}
// Record completion time of the write
assert(it->second.complete == TICK_FUTURE);
it->second.complete = _complete;
// Update max completion time for the cluster
if (completeMax < _complete) {
completeMax = _complete;
}
if (--numIncomplete == 0) {
// All writes have completed, this cluster is now complete and will be
// assigned the max of completion tick values among all writes.
//
// Note that we cannot simply keep updating complete, because that
// would count the cluster as closed already. Instead, we keep
// TICK_FUTURE until all writes have completed.
complete = completeMax;
}
}
void
MemChecker::WriteCluster::abortWrite(MemChecker::Serial serial)
{
if (!writes.erase(serial)) {
warn("Could not locate write transaction: serial = %d\n", serial);
return;
}
if (--numIncomplete == 0 && !writes.empty()) {
// This write cluster is now complete, and we can assign the current
// completeMax value.
complete = completeMax;
}
// Note: this WriteCluster is in pristine state if this was the only
// write present; the cluster will get reused through
// getIncompleteWriteCluster().
}
void
MemChecker::ByteTracker::startRead(MemChecker::Serial serial, Tick start)
{
outstandingReads.insert(std::make_pair(serial,
MemChecker::Transaction(serial, start, TICK_FUTURE)));
}
bool
MemChecker::ByteTracker::inExpectedData(Tick start, Tick complete,
uint8_t data)
{
_lastExpectedData.clear();
bool wc_overlap = true;
// Find the last value read from the location
const Transaction& last_obs =
*lastCompletedTransaction(&readObservations, start);
bool last_obs_valid = (last_obs.complete != TICK_INITIAL);
// Scan backwards through the write clusters to find the closest younger
// preceding & overlapping writes.
for (auto cluster = writeClusters.rbegin();
cluster != writeClusters.rend() && wc_overlap; ++cluster) {
for (const auto& addr_write : cluster->writes) {
const Transaction& write = addr_write.second;
if (write.complete < last_obs.start) {
// If this write transaction completed before the last
// observation, we ignore it as the last_observation has the
// correct value
continue;
}
if (write.data == data) {
// Found a match, end search.
return true;
}
// Record possible, but non-matching data for debugging
_lastExpectedData.push_back(write.data);
if (write.complete > start) {
// This write overlapped with the transaction we want to check
// -> continue checking the overlapping write cluster
continue;
}
// This write cluster has writes that have completed before the
// checked transaction. There is no need to check an earlier
// write-cluster -> set the exit condition for the outer loop
wc_overlap = false;
if (last_obs.complete < write.start) {
// We found a write which started after the last observed read,
// therefore we can not longer consider the value seen by the
// last observation as a valid expected value.
//
// Once all writes have been iterated through, we can check if
// the last observation is still valid to compare against.
last_obs_valid = false;
}
}
}
// We have not found any matching write, so far; check other sources of
// confirmation
if (last_obs_valid) {
// The last observation is not outdated according to the writes we have
// seen so far.
assert(last_obs.complete <= start);
if (last_obs.data == data) {
// Matched data from last observation -> all good
return true;
}
// Record non-matching, but possible value
_lastExpectedData.push_back(last_obs.data);
} else {
// We have not seen any valid observation, and the only writes
// observed are overlapping, so anything (in particular the
// initialisation value) goes
// NOTE: We can overlap with multiple write clusters, here
if (!writeClusters.empty() && wc_overlap) {
// ensure that all write clusters really overlap this read
assert(writeClusters.begin()->start < complete &&
writeClusters.rbegin()->complete > start);
return true;
}
}
if (_lastExpectedData.empty()) {
assert(last_obs.complete == TICK_INITIAL);
// We have not found any possible (non-matching data). Can happen in
// initial system state
DPRINTF(MemChecker, "no last observation nor write! start = %d, "\
"complete = %d, data = %#x\n", start, complete, data);
return true;
}
return false;
}
bool
MemChecker::ByteTracker::completeRead(MemChecker::Serial serial,
Tick complete, uint8_t data)
{
auto it = outstandingReads.find(serial);
if (it == outstandingReads.end()) {
// Can happen if concurrent with reset_address_range
warn("Could not locate read transaction: serial = %d, complete = %d\n",
serial, complete);
return true;
}
Tick start = it->second.start;
outstandingReads.erase(it);
// Verify data
const bool result = inExpectedData(start, complete, data);
readObservations.emplace_back(serial, start, complete, data);
pruneTransactions();
return result;
}
MemChecker::WriteCluster*
MemChecker::ByteTracker::getIncompleteWriteCluster()
{
if (writeClusters.empty() || writeClusters.back().isComplete()) {
writeClusters.emplace_back();
}
return &writeClusters.back();
}
void
MemChecker::ByteTracker::startWrite(MemChecker::Serial serial, Tick start,
uint8_t data)
{
getIncompleteWriteCluster()->startWrite(serial, start, data);
}
void
MemChecker::ByteTracker::completeWrite(MemChecker::Serial serial,
Tick complete)
{
getIncompleteWriteCluster()->completeWrite(serial, complete);
pruneTransactions();
}
void
MemChecker::ByteTracker::abortWrite(MemChecker::Serial serial)
{
getIncompleteWriteCluster()->abortWrite(serial);
}
void
MemChecker::ByteTracker::pruneTransactions()
{
// Obtain tick of first outstanding read. If there are no outstanding
// reads, we use curTick(), i.e. we will remove all readObservation except
// the most recent one.
const Tick before = outstandingReads.empty() ? curTick() :
outstandingReads.begin()->second.start;
// Pruning of readObservations
readObservations.erase(readObservations.begin(),
lastCompletedTransaction(&readObservations, before));
// Pruning of writeClusters
if (!writeClusters.empty()) {
writeClusters.erase(writeClusters.begin(),
lastCompletedTransaction(&writeClusters, before));
}
}
bool
MemChecker::completeRead(MemChecker::Serial serial, Tick complete,
Addr addr, size_t size, uint8_t *data)
{
bool result = true;
DPRINTF(MemChecker,
"completing read: serial = %d, complete = %d, "
"addr = %#llx, size = %d\n", serial, complete, addr, size);
for (size_t i = 0; i < size; ++i) {
ByteTracker *tracker = getByteTracker(addr + i);
if (!tracker->completeRead(serial, complete, data[i])) {
// Generate error message, and aggregate all failures for the bytes
// considered in this transaction in one message.
if (result) {
result = false;
errorMessage = "";
} else {
errorMessage += "\n";
}
errorMessage += csprintf(" Read transaction for address %#llx "
"failed: received %#x, expected ",
(unsigned long long)(addr + i), data[i]);
for (size_t j = 0; j < tracker->lastExpectedData().size(); ++j) {
errorMessage +=
csprintf("%#x%s",
tracker->lastExpectedData()[j],
(j == tracker->lastExpectedData().size() - 1)
? "" : "|");
}
}
}
if (!result) {
DPRINTF(MemChecker, "read of %#llx @ cycle %d failed:\n%s\n", addr,
complete, errorMessage);
}
return result;
}
void
MemChecker::reset(Addr addr, size_t size)
{
for (size_t i = 0; i < size; ++i) {
byte_trackers.erase(addr + i);
}
}
} // namespace gem5