mem: Add support for writing back and flushing caches

This patch adds support for the following optional drain methods in
the classical memory system's cache model:

memWriteback() - Write back all dirty cache lines to memory using
functional accesses.

memInvalidate() - Invalidate all cache lines. Dirty cache lines
are lost unless a writeback is requested.

Since memWriteback() is called when checkpointing systems, this patch
adds support for checkpointing systems with caches. The serialization
code now checks whether there are any dirty lines in the cache. If
there are dirty lines in the cache, the checkpoint is flagged as bad
and a warning is printed.

4 files changed, 108 insertions, 0 deletions

diff --git a/src/mem/cache/tags/base.hh b/src/mem/cache/tags/base.hh
index 576b512e5..3539f2bfd 100644
--- a/src/mem/cache/tags/base.hh
+++ b/src/mem/cache/tags/base.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2012 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
+ * property including but not limited to intellectual property relating
+ * 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
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2003-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
diff --git a/src/mem/cache/tags/fa_lru.hh b/src/mem/cache/tags/fa_lru.hh
index 19e21688c..7604d8d43 100644
--- a/src/mem/cache/tags/fa_lru.hh
+++ b/src/mem/cache/tags/fa_lru.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2012 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
+ * property including but not limited to intellectual property relating
+ * 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
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2003-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -287,6 +299,26 @@ public:
      *Needed to clear all lock tracking at once
      */
     virtual void clearLocks();
+
+    /**
+     * Visit each block in the tag store and apply a visitor to the
+     * block.
+     *
+     * The visitor should be a function (or object that behaves like a
+     * function) that takes a cache block reference as its parameter
+     * and returns a bool. A visitor can request the traversal to be
+     * stopped by returning false, returning true causes it to be
+     * called for the next block in the tag store.
+     *
+     * \param visitor Visitor to call on each block.
+     */
+    template <typename V>
+    void forEachBlk(V &visitor) {
+        for (int i = 0; i < numBlocks; i++) {
+            if (!visitor(blks[i]))
+                return;
+        }
+    }
 };
 
 #endif // __MEM_CACHE_TAGS_FA_LRU_HH__
diff --git a/src/mem/cache/tags/iic.hh b/src/mem/cache/tags/iic.hh
index 91e947704..a41af8612 100644
--- a/src/mem/cache/tags/iic.hh
+++ b/src/mem/cache/tags/iic.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2012 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
+ * property including but not limited to intellectual property relating
+ * 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
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2002-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -450,6 +462,26 @@ class IIC : public BaseTags
      */
     virtual void cleanupRefs();
 
+    /**
+     * Visit each block in the tag store and apply a visitor to the
+     * block.
+     *
+     * The visitor should be a function (or object that behaves like a
+     * function) that takes a cache block reference as its parameter
+     * and returns a bool. A visitor can request the traversal to be
+     * stopped by returning false, returning true causes it to be
+     * called for the next block in the tag store.
+     *
+     * \param visitor Visitor to call on each block.
+     */
+    template <typename V>
+    void forEachBlk(V &visitor) {
+        for (unsigned i = 0; i < numTags; ++i) {
+            if (!visitor(tagStore[i]))
+                return;
+        }
+    }
+
 private:
     /**
      * Return the hash of the address.
diff --git a/src/mem/cache/tags/lru.hh b/src/mem/cache/tags/lru.hh
index 427dba667..431e3eb1e 100644
--- a/src/mem/cache/tags/lru.hh
+++ b/src/mem/cache/tags/lru.hh
@@ -1,4 +1,16 @@
 /*
+ * Copyright (c) 2012 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
+ * property including but not limited to intellectual property relating
+ * 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
+ * unmodified and in its entirety in all distributions of the software,
+ * modified or unmodified, in source code or in binary form.
+ *
  * Copyright (c) 2003-2005 The Regents of The University of Michigan
  * All rights reserved.
  *
@@ -235,6 +247,26 @@ public:
      * Called at end of simulation to complete average block reference stats.
      */
     virtual void cleanupRefs();
+
+    /**
+     * Visit each block in the tag store and apply a visitor to the
+     * block.
+     *
+     * The visitor should be a function (or object that behaves like a
+     * function) that takes a cache block reference as its parameter
+     * and returns a bool. A visitor can request the traversal to be
+     * stopped by returning false, returning true causes it to be
+     * called for the next block in the tag store.
+     *
+     * \param visitor Visitor to call on each block.
+     */
+    template <typename V>
+    void forEachBlk(V &visitor) {
+        for (unsigned i = 0; i < numSets * assoc; ++i) {
+            if (!visitor(blks[i]))
+                return;
+        }
+    }
 };
 
 #endif // __MEM_CACHE_TAGS_LRU_HH__