2 files changed, 39 insertions, 1 deletions

diff --git a/src/mem/port.cc b/src/mem/port.cc
index 001576fe3..933e98243 100644
--- a/src/mem/port.cc
+++ b/src/mem/port.cc
@@ -144,6 +144,13 @@ MasterPort::sendAtomic(PacketPtr pkt)
     return _slavePort->recvAtomic(pkt);
 }
 
+Tick
+MasterPort::sendAtomicBackdoor(PacketPtr pkt, MemBackdoorPtr &backdoor)
+{
+    assert(pkt->isRequest());
+    return _slavePort->recvAtomicBackdoor(pkt, backdoor);
+}
+
 void
 MasterPort::sendFunctional(PacketPtr pkt)
 {
@@ -195,7 +202,8 @@ MasterPort::printAddr(Addr a)
  * Slave port
  */
 SlavePort::SlavePort(const std::string& name, MemObject* _owner, PortID id)
-    : BaseSlavePort(name, id), _masterPort(NULL), owner(*_owner)
+    : BaseSlavePort(name, id), _masterPort(NULL), defaultBackdoorWarned(false),
+    owner(*_owner)
 {
 }
 
@@ -220,6 +228,16 @@ SlavePort::slaveBind(MasterPort& master_port)
 }
 
 Tick
+SlavePort::recvAtomicBackdoor(PacketPtr pkt, MemBackdoorPtr &backdoor)
+{
+    if (!defaultBackdoorWarned) {
+        warn("Port %s doesn't support requesting a back door.", name());
+        defaultBackdoorWarned = true;
+    }
+    return recvAtomic(pkt);
+}
+
+Tick
 SlavePort::sendAtomicSnoop(PacketPtr pkt)
 {
     assert(pkt->isRequest());
diff --git a/src/mem/port.hh b/src/mem/port.hh
index 2154da007..72a02711c 100644
--- a/src/mem/port.hh
+++ b/src/mem/port.hh
@@ -51,6 +51,7 @@
 #define __MEM_PORT_HH__
 
 #include "base/addr_range.hh"
+#include "mem/backdoor.hh"
 #include "mem/packet.hh"
 #include "sim/port.hh"
 
@@ -153,6 +154,18 @@ class MasterPort : public BaseMasterPort
     Tick sendAtomic(PacketPtr pkt);
 
     /**
+     * Send an atomic request packet like above, but also request a backdoor
+     * to the data being accessed.
+     *
+     * @param pkt Packet to send.
+     * @param backdoor Can be set to a back door pointer by the target to let
+     *        caller have direct access to the requested data.
+     *
+     * @return Estimated latency of access.
+     */
+    Tick sendAtomicBackdoor(PacketPtr pkt, MemBackdoorPtr &backdoor);
+
+    /**
      * Send a functional request packet, where the data is instantly
      * updated everywhere in the memory system, without affecting the
      * current state of any block or moving the block.
@@ -300,6 +313,7 @@ class SlavePort : public BaseSlavePort
   private:
 
     MasterPort* _masterPort;
+    bool defaultBackdoorWarned;
 
   protected:
 
@@ -416,6 +430,12 @@ class SlavePort : public BaseSlavePort
     virtual Tick recvAtomic(PacketPtr pkt) = 0;
 
     /**
+     * Receive an atomic request packet from the master port, and optionally
+     * provide a backdoor to the data being accessed.
+     */
+    virtual Tick recvAtomicBackdoor(PacketPtr pkt, MemBackdoorPtr &backdoor);
+
+    /**
      * Receive a functional request packet from the master port.
      */
     virtual void recvFunctional(PacketPtr pkt) = 0;