// like a Writeback which could not find a replaceable block so has to
// go to next level.
return false;
+ } else if (pkt->cmd == MemCmd::WriteClean) {
+ // WriteClean handling is a special case. We can allocate a
+ // block directly if it doesn't exist and we can update the
+ // block immediately. The WriteClean transfers the ownership
+ // of the block as well.
+ assert(blkSize == pkt->getSize());
+
+ if (!blk) {
+ // a writeback that misses needs to allocate a new block
+ blk = allocateBlock(pkt->getAddr(), pkt->isSecure(),
+ writebacks);
+ if (!blk) {
+ // no replaceable block available: give up, fwd to
+ // next level.
+ incMissCount(pkt);
+ return false;
+ }
+ tags->insertBlock(pkt, blk);
+
+ blk->status = (BlkValid | BlkReadable);
+ if (pkt->isSecure()) {
+ blk->status |= BlkSecure;
+ }
+ }
+
+ // at this point either this is a writeback or a write-through
+ // write clean operation and the block is already in this
+ // cache, we need to update the data and the block flags
+ assert(blk);
+ blk->status |= BlkDirty;
+ // nothing else to do; writeback doesn't expect response
+ assert(!pkt->needsResponse());
+ std::memcpy(blk->data, pkt->getConstPtr<uint8_t>(), blkSize);
+ DPRINTF(Cache, "%s new state is %s\n", __func__, blk->print());
+
+ incHitCount(pkt);
+ // populate the time when the block will be ready to access.
+ blk->whenReady = clockEdge(fillLatency) + pkt->headerDelay +
+ pkt->payloadDelay;
+ return true;
} else if (blk && (pkt->needsWritable() ? blk->isWritable() :
blk->isReadable())) {
// OK to satisfy access
while (!writebacks.empty()) {
PacketPtr wbPkt = writebacks.front();
// We use forwardLatency here because we are copying writebacks to
- // write buffer. Call isCachedAbove for both Writebacks and
- // CleanEvicts. If isCachedAbove returns true we set BLOCK_CACHED flag
- // in Writebacks and discard CleanEvicts.
+ // write buffer.
+
+ // Call isCachedAbove for Writebacks, CleanEvicts and
+ // WriteCleans to discover if the block is cached above.
if (isCachedAbove(wbPkt)) {
if (wbPkt->cmd == MemCmd::CleanEvict) {
// Delete CleanEvict because cached copies exist above. The
assert(writebackClean);
delete wbPkt;
} else {
- assert(wbPkt->cmd == MemCmd::WritebackDirty);
+ assert(wbPkt->cmd == MemCmd::WritebackDirty ||
+ wbPkt->cmd == MemCmd::WriteClean);
// Set BLOCK_CACHED flag in Writeback and send below, so that
// the Writeback does not reset the bit corresponding to this
// address in the snoop filter below.
// isCachedAbove returns true we set BLOCK_CACHED flag in Writebacks
// and discard CleanEvicts.
if (isCachedAbove(wbPkt, false)) {
- if (wbPkt->cmd == MemCmd::WritebackDirty) {
+ if (wbPkt->cmd == MemCmd::WritebackDirty ||
+ wbPkt->cmd == MemCmd::WriteClean) {
// Set BLOCK_CACHED flag in Writeback and send below,
// so that the Writeback does not reset the bit
// corresponding to this address in the snoop filter
mshr_misses[pkt->cmdToIndex()][pkt->req->masterId()]++;
}
- if (pkt->isEviction() ||
+ if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean ||
(pkt->req->isUncacheable() && pkt->isWrite())) {
// We use forward_time here because there is an
// uncached memory write, forwarded to WriteBuffer.
// MISS
// deal with the packets that go through the write path of
- // the cache, i.e. any evictions and uncacheable writes
- if (pkt->isEviction() ||
+ // the cache, i.e. any evictions and writes
+ if (pkt->isEviction() || pkt->cmd == MemCmd::WriteClean ||
(pkt->req->isUncacheable() && pkt->isWrite())) {
lat += ticksToCycles(memSidePort->sendAtomic(pkt));
return lat * clockPeriod();
return pkt;
}
+PacketPtr
+Cache::writecleanBlk(CacheBlk *blk)
+{
+ Request *req = new Request(tags->regenerateBlkAddr(blk->tag, blk->set),
+ blkSize, 0, Request::wbMasterId);
+ if (blk->isSecure()) {
+ req->setFlags(Request::SECURE);
+ }
+ req->taskId(blk->task_id);
+ blk->task_id = ContextSwitchTaskId::Unknown;
+ PacketPtr pkt = new Packet(req, MemCmd::WriteClean);
+ DPRINTF(Cache, "Create %s writable: %d, dirty: %d\n", pkt->print(),
+ blk->isWritable(), blk->isDirty());
+ // make sure the block is not marked dirty
+ blk->status &= ~BlkDirty;
+ pkt->allocate();
+ // We inform the cache below that the block has sharers in the
+ // system as we retain our copy.
+ pkt->setHasSharers();
+ std::memcpy(pkt->getPtr<uint8_t>(), blk->data, blkSize);
+ return pkt;
+}
+
+
PacketPtr
Cache::cleanEvictBlk(CacheBlk *blk)
{
// Writebacks/CleanEvicts.
assert(wb_entry->getNumTargets() == 1);
PacketPtr wb_pkt = wb_entry->getTarget()->pkt;
- assert(wb_pkt->isEviction());
+ assert(wb_pkt->isEviction() || wb_pkt->cmd == MemCmd::WriteClean);
if (pkt->isEviction()) {
// if the block is found in the write queue, set the BLOCK_CACHED
// Assert that packet is either Writeback or CleanEvict and not a
// prefetch request because prefetch requests need an MSHR and may
// generate a snoop response.
- assert(pkt->isEviction());
+ assert(pkt->isEviction() || pkt->cmd == MemCmd::WriteClean);
snoop_pkt.senderState = nullptr;
cpuSidePort->sendTimingSnoopReq(&snoop_pkt);
// Writeback/CleanEvict snoops do not generate a snoop response.
projects / gem5.git / commitdiff