sret bugfix: bypass arbiter

rocket/src/main/scala/rocc.scala

@@ -121,6 +121,7 @@ class AccumulatorExample extends RoCC
   io.mem.req.bits.cmd := M_XRD // perform a load (M_XWR for stores)
   io.mem.req.bits.typ := MT_D // D = 8 bytes, W = 4, H = 2, B = 1
   io.mem.req.bits.data := Bits(0) // we're not performing any stores...
+  io.mem.sret := false
 
   io.imem.acquire.valid := false
   io.imem.grant.ready := false

rocket/src/main/scala/tile.scala

@@ -26,6 +26,7 @@ class RocketTile(resetSignal: Bool = null) extends Tile(resetSignal) {
   val ptw = Module(new PTW(params(NPTWPorts)))
   val core = Module(new Core, { case CoreName => "Rocket" })
 
+  dcache.io.cpu.sret := core.io.dmem.sret
   val dcArb = Module(new HellaCacheArbiter(params(NDCachePorts)))
   dcArb.io.requestor(0) <> ptw.io.mem
   dcArb.io.requestor(1) <> core.io.dmem