// special handling for coherent block requests from
// upper-level caches
if (pkt->needsExclusive()) {
+ // sanity check
+ assert(pkt->cmd == MemCmd::ReadExReq ||
+ pkt->cmd == MemCmd::SCUpgradeFailReq);
+
// if we have a dirty copy, make sure the recipient
// keeps it marked dirty
if (blk->isDirty()) {
if (blk != tempBlock)
tags->invalidate(blk);
blk->invalidate();
- } else if (blk->isWritable() && !pending_downgrade
- && !pkt->sharedAsserted() && !pkt->req->isInstFetch()) {
+ } else if (blk->isWritable() && !pending_downgrade &&
+ !pkt->sharedAsserted() &&
+ pkt->cmd != MemCmd::ReadCleanReq) {
// we can give the requester an exclusive copy (by not
// asserting shared line) on a read request if:
// - we have an exclusive copy at this level (& below)
cmd = cpu_pkt->cmd;
} else {
// block is invalid
- cmd = needsExclusive ? MemCmd::ReadExReq : MemCmd::ReadReq;
+ cmd = needsExclusive ? MemCmd::ReadExReq :
+ (isReadOnly ? MemCmd::ReadCleanReq : MemCmd::ReadSharedReq);
}
PacketPtr pkt = new Packet(cpu_pkt->req, cmd, blkSize);
{
/* InvalidCmd */
{ 0, InvalidCmd, "InvalidCmd" },
- /* ReadReq */
+ /* ReadReq - Read issued by a non-caching agent such as a CPU or
+ * device, with no restrictions on alignment. */
{ SET3(IsRead, IsRequest, NeedsResponse), ReadResp, "ReadReq" },
/* ReadResp */
{ SET3(IsRead, IsResponse, HasData), InvalidCmd, "ReadResp" },
* that it has failed, acquires line as Dirty*/
{ SET4(IsRead, NeedsExclusive, IsResponse, HasData),
InvalidCmd, "UpgradeFailResp" },
- /* ReadExReq */
+ /* ReadExReq - Read issues by a cache, always cache-line aligned,
+ * and the response is guaranteed to be writeable (exclusive or
+ * even modified) */
{ SET5(IsRead, NeedsExclusive, IsInvalidate, IsRequest, NeedsResponse),
ReadExResp, "ReadExReq" },
- /* ReadExResp */
+ /* ReadExResp - Response matching a read exclusive, as we check
+ * the need for exclusive also on responses */
{ SET4(IsRead, NeedsExclusive, IsResponse, HasData),
InvalidCmd, "ReadExResp" },
+ /* ReadCleanReq - Read issued by a cache, always cache-line
+ * aligned, and the response is guaranteed to not contain dirty data
+ * (exclusive or shared).*/
+ { SET3(IsRead, IsRequest, NeedsResponse), ReadResp, "ReadCleanReq" },
+ /* ReadSharedReq - Read issued by a cache, always cache-line
+ * aligned, response is shared, possibly exclusive, owned or even
+ * modified. */
+ { SET3(IsRead, IsRequest, NeedsResponse), ReadResp, "ReadSharedReq" },
/* LoadLockedReq: note that we use plain ReadResp as response, so that
* we can also use ReadRespWithInvalidate when needed */
{ SET4(IsRead, IsLlsc, IsRequest, NeedsResponse),