ruby: improved support for functional accesses

This patch adds support to different entities in the ruby memory system
for more reliable functional read/write accesses. Only the simple network
has been augmented as of now. Later on Garnet will also support functional
accesses.
The patch adds functional access code to all the different types of messages
that protocols can send around. These messages are functionally accessed
by going through the buffers maintained by the network entities.
The patch also rectifies some of the bugs found in coherence protocols while
testing the patch.

With this patch applied, functional writes always succeed. But functional
reads can still fail.

1 files changed, 57 insertions, 0 deletions

diff --git a/src/mem/protocol/MOESI_hammer-msg.sm b/src/mem/protocol/MOESI_hammer-msg.sm
index 6ead7200a..41d176a9c 100644
--- a/src/mem/protocol/MOESI_hammer-msg.sm
+++ b/src/mem/protocol/MOESI_hammer-msg.sm
@@ -73,6 +73,16 @@ enumeration(TriggerType, desc="...") {
 structure(TriggerMsg, desc="...", interface="Message") {
   Address Address,             desc="Physical address for this request";
   TriggerType Type,            desc="Type of trigger";
+
+  bool functionalRead(Packet *pkt) {
+    // Trigger messages do not hold any data!
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // Trigger messages do not hold any data!
+    return false;
+  }
 }
 
 // RequestMsg (and also forwarded requests)
@@ -87,6 +97,16 @@ structure(RequestMsg, desc="...", interface="NetworkMessage") {
   Time InitialRequestTime, default="0", desc="time the initial requests was sent from the L1Cache";
   Time ForwardRequestTime, default="0", desc="time the dir forwarded the request";
   int SilentAcks, default="0", desc="silent acks from the full-bit directory";
+
+  bool functionalRead(Packet *pkt) {
+    // Request messages do not hold any data
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // Request messages do not hold any data
+    return false;
+  }
 }
 
 // ResponseMsg (and also unblock requests)
@@ -103,6 +123,27 @@ structure(ResponseMsg, desc="...", interface="NetworkMessage") {
   Time InitialRequestTime, default="0", desc="time the initial requests was sent from the L1Cache";
   Time ForwardRequestTime, default="0", desc="time the dir forwarded the request";
   int SilentAcks, default="0", desc="silent acks from the full-bit directory";
+
+  bool functionalRead(Packet *pkt) {
+    // The check below ensures that data is read only from messages that
+    // actually hold data.
+    if (Type == CoherenceResponseType:DATA ||
+        Type == CoherenceResponseType:DATA_SHARED ||
+        Type == CoherenceResponseType:DATA_EXCLUSIVE ||
+        Type == CoherenceResponseType:WB_DIRTY ||
+        Type == CoherenceResponseType:WB_EXCLUSIVE_DIRTY) {
+        return testAndRead(Address, DataBlk, pkt);
+    }
+
+    return false;
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    // Message type does not matter since all messages are written.
+    // If a protocol reads data from a packet that is not supposed
+    // to hold the data, then the fault lies with the protocol.
+    return testAndWrite(Address, DataBlk, pkt);
+  }
 }
 
 enumeration(DMARequestType, desc="...", default="DMARequestType_NULL") {
@@ -126,6 +167,14 @@ structure(DMARequestMsg, desc="...", interface="NetworkMessage") {
   DataBlock DataBlk,         desc="DataBlk attached to this request";
   int Len,                   desc="The length of the request";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    return testAndRead(LineAddress, DataBlk, pkt);
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    return testAndWrite(LineAddress, DataBlk, pkt);
+  }
 }
 
 structure(DMAResponseMsg, desc="...", interface="NetworkMessage") {
@@ -135,4 +184,12 @@ structure(DMAResponseMsg, desc="...", interface="NetworkMessage") {
   NetDest Destination,       desc="Destination";
   DataBlock DataBlk,         desc="DataBlk attached to this request";
   MessageSizeType MessageSize, desc="size category of the message";
+
+  bool functionalRead(Packet *pkt) {
+    return testAndRead(LineAddress, DataBlk, pkt);
+  }
+
+  bool functionalWrite(Packet *pkt) {
+    return testAndWrite(LineAddress, DataBlk, pkt);
+  }
 }