mem: Support WriteInvalidate (again)

This patch takes a clean-slate approach to providing WriteInvalidate
(write streaming, full cache line writes without first reading)
support.

Unlike the prior attempt, which took an aggressive approach of directly
writing into the cache before handling the coherence actions, this
approach follows the existing cache flows as closely as possible.

1 files changed, 24 insertions, 21 deletions

diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index 9320d7886..8e3bcdd37 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -177,14 +177,16 @@ class MemCmd
 
   public:
 
-    bool isRead() const         { return testCmdAttrib(IsRead); }
-    bool isWrite() const        { return testCmdAttrib(IsWrite); }
-    bool isUpgrade() const      { return testCmdAttrib(IsUpgrade); }
-    bool isRequest() const      { return testCmdAttrib(IsRequest); }
-    bool isResponse() const     { return testCmdAttrib(IsResponse); }
-    bool needsExclusive() const { return testCmdAttrib(NeedsExclusive); }
-    bool needsResponse() const  { return testCmdAttrib(NeedsResponse); }
-    bool isInvalidate() const   { return testCmdAttrib(IsInvalidate); }
+    bool isRead() const            { return testCmdAttrib(IsRead); }
+    bool isWrite() const           { return testCmdAttrib(IsWrite); }
+    bool isUpgrade() const         { return testCmdAttrib(IsUpgrade); }
+    bool isRequest() const         { return testCmdAttrib(IsRequest); }
+    bool isResponse() const        { return testCmdAttrib(IsResponse); }
+    bool needsExclusive() const    { return testCmdAttrib(NeedsExclusive); }
+    bool needsResponse() const     { return testCmdAttrib(NeedsResponse); }
+    bool isInvalidate() const      { return testCmdAttrib(IsInvalidate); }
+    bool isWriteInvalidate() const { return testCmdAttrib(IsWrite) &&
+                                            testCmdAttrib(IsInvalidate); }
 
     /**
      * Check if this particular packet type carries payload data. Note
@@ -495,19 +497,20 @@ class Packet : public Printable
     /// Return the index of this command.
     inline int cmdToIndex() const { return cmd.toInt(); }
 
-    bool isRead() const         { return cmd.isRead(); }
-    bool isWrite() const        { return cmd.isWrite(); }
-    bool isUpgrade()  const     { return cmd.isUpgrade(); }
-    bool isRequest() const      { return cmd.isRequest(); }
-    bool isResponse() const     { return cmd.isResponse(); }
-    bool needsExclusive() const { return cmd.needsExclusive(); }
-    bool needsResponse() const  { return cmd.needsResponse(); }
-    bool isInvalidate() const   { return cmd.isInvalidate(); }
-    bool hasData() const        { return cmd.hasData(); }
-    bool isLLSC() const         { return cmd.isLLSC(); }
-    bool isError() const        { return cmd.isError(); }
-    bool isPrint() const        { return cmd.isPrint(); }
-    bool isFlush() const        { return cmd.isFlush(); }
+    bool isRead() const              { return cmd.isRead(); }
+    bool isWrite() const             { return cmd.isWrite(); }
+    bool isUpgrade()  const          { return cmd.isUpgrade(); }
+    bool isRequest() const           { return cmd.isRequest(); }
+    bool isResponse() const          { return cmd.isResponse(); }
+    bool needsExclusive() const      { return cmd.needsExclusive(); }
+    bool needsResponse() const       { return cmd.needsResponse(); }
+    bool isInvalidate() const        { return cmd.isInvalidate(); }
+    bool isWriteInvalidate() const   { return cmd.isWriteInvalidate(); }
+    bool hasData() const             { return cmd.hasData(); }
+    bool isLLSC() const              { return cmd.isLLSC(); }
+    bool isError() const             { return cmd.isError(); }
+    bool isPrint() const             { return cmd.isPrint(); }
+    bool isFlush() const             { return cmd.isFlush(); }
 
     // Snoop flags
     void assertMemInhibit()