mem: Snoop into caches on uncacheable accesses

This patch takes a last step in fixing issues related to uncacheable
accesses. We do not separate uncacheable memory from uncacheable
devices, and in cases where it is really memory, there are valid
scenarios where we need to snoop since we do not support cache
maintenance instructions (yet). On snooping an uncacheable access we
thus provide data if possible. In essence this makes uncacheable
accesses IO coherent.

The snoop filter is also queried to steer the snoops, but not updated
since the uncacheable accesses do not allocate a block.

1 files changed, 10 insertions, 0 deletions

diff --git a/src/mem/cache/base.hh b/src/mem/cache/base.hh
index 2bac2d30f..aaf0ea691 100644
--- a/src/mem/cache/base.hh
+++ b/src/mem/cache/base.hh
@@ -262,6 +262,16 @@ class BaseCache : public MemObject
      */
     virtual bool isDirty() const = 0;
 
+    /**
+     * Determine if an address is in the ranges covered by this
+     * cache. This is useful to filter snoops.
+     *
+     * @param addr Address to check against
+     *
+     * @return If the address in question is in range
+     */
+    bool inRange(Addr addr) const;
+
     /** Block size of this cache */
     const unsigned blkSize;