rework csr exception/interrupt handeling wip

src/main/scala/vexriscv/Pipeline.scala

@@ -122,7 +122,7 @@ trait Pipeline {
     }
 
     for(stageIndex <- 0 until stages.length; stage = stages(stageIndex)){
-      stage.arbitration.isStuckByOthers := stage.arbitration.haltByOther || stages.takeRight(stages.length - stageIndex - 1).map(s => s.arbitration.haltItself/* && !s.arbitration.removeIt*/).foldLeft(False)(_ || _)
+      stage.arbitration.isStuckByOthers := stage.arbitration.haltByOther || stages.takeRight(stages.length - stageIndex - 1).map(s => s.arbitration.isStuck/* && !s.arbitration.removeIt*/).foldLeft(False)(_ || _)
       stage.arbitration.isStuck := stage.arbitration.haltItself || stage.arbitration.isStuckByOthers
       stage.arbitration.isMoving := !stage.arbitration.isStuck && !stage.arbitration.removeIt
       stage.arbitration.isFiring := stage.arbitration.isValid && !stage.arbitration.isStuck && !stage.arbitration.removeIt

src/main/scala/vexriscv/Services.scala

@@ -14,7 +14,7 @@ trait JumpService{
 trait IBusFetcher{
   def haltIt() : Unit
   def incoming() : Bool
-  def nextPc() : (Bool, UInt)
+  def pcValid(stage : Stage) : Bool
   def getInjectionPort() : Stream[Bits]
 }
 

src/main/scala/vexriscv/TestsWorkspace.scala

@@ -33,14 +33,14 @@ object TestsWorkspace {
         plugins = List(
           new IBusSimplePlugin(
             resetVector = 0x80000000l,
-            relaxedPcCalculation = true,
+            relaxedPcCalculation = false,
             relaxedBusCmdValid = false,
             prediction = NONE,
             historyRamSizeLog2 = 10,
             catchAccessFault = true,
             compressedGen = false,
-            busLatencyMin = 3,
+            busLatencyMin = 1,
-            injectorStage = false
+            injectorStage = true
           ),
 //          new IBusCachedPlugin(
 //            resetVector = 0x80000000l,

src/main/scala/vexriscv/demo/SynthesisBench.scala

@@ -101,8 +101,8 @@ object VexRiscvSynthesisBench {
     }
 
 
-    val rtls = List(smallestNoCsr, smallest, smallAndProductive, smallAndProductiveWithICache, fullNoMmuNoCache, noCacheNoMmuMaxPerf, fullNoMmuMaxPerf, fullNoMmu, full)
+//    val rtls = List(smallestNoCsr, smallest, smallAndProductive, smallAndProductiveWithICache, fullNoMmuNoCache, noCacheNoMmuMaxPerf, fullNoMmuMaxPerf, fullNoMmu, full)
-//    val rtls = List(noCacheNoMmuMaxPerf, fullNoMmuMaxPerf)
+    val rtls = List(smallestNoCsr, smallest, smallAndProductive)
     //      val rtls = List(smallAndProductive, smallAndProductiveWithICache, fullNoMmuMaxPerf, fullNoMmu, full)
 //    val rtls = List(smallAndProductive,  full)
 

src/main/scala/vexriscv/plugin/CsrPlugin.scala

@@ -260,7 +260,7 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
     if(ecallGen) decoderService.add(ECALL,  defaultEnv ++ List(ENV_CTRL -> EnvCtrlEnum.ECALL))
 
     val  pcManagerService = pipeline.service(classOf[JumpService])
-    jumpInterface = pcManagerService.createJumpInterface(pipeline.execute)
+    jumpInterface = pcManagerService.createJumpInterface(pipeline.writeBack)
     jumpInterface.valid := False
     jumpInterface.payload.assignDontCare()
 
@@ -372,15 +372,15 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
         minstret := minstret + 1
       }
 
-
+      val mepcCaptureStage = if(exceptionPortsInfos.nonEmpty) writeBack else decode
 
       //Used to make the pipeline empty softly (for interrupts)
       val pipelineLiberator = new Area{
         val enable = False.noBackendCombMerge //Verilator Perf
-        when(enable){
+        when(enable && decode.arbitration.isValid){
           decode.arbitration.haltByOther := True
         }
-        val done = ! List(execute, memory, writeBack).map(_.arbitration.isValid).orR && !fetcher.nextPc()._1
+        val done = !List(execute, memory, writeBack).map(_.arbitration.isValid).orR && fetcher.pcValid(mepcCaptureStage)
       }
 
 
@@ -392,11 +392,6 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
         val exceptionValidsRegs = Vec(stages.map(s => Reg(Bool).init(False).setPartialName(s.getName()))).allowUnsetRegToAvoidLatch
         val exceptionContext = Reg(ExceptionCause())
 
-        //Assume 2 stages before decode
-        when(exceptionValidsRegs.drop(1).orR) {
-          decode.arbitration.haltByOther := True
-        }
-
         val groupedByStage = exceptionPortsInfos.map(_.stage).distinct.map(s => {
           val stagePortsInfos = exceptionPortsInfos.filter(_.stage == s).sortWith(_.priority > _.priority)
           val stagePort = stagePortsInfos.length match{
@@ -418,14 +413,15 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
         exceptionValids := exceptionValidsRegs
         for(portInfo <- sortedByStage; port = portInfo.port ; stage = portInfo.stage; stageId = indexOf(portInfo.stage)) {
           when(port.valid) {
-            if(indexOf(stage) != 0) stages(indexOf(stage) - 1).arbitration.flushAll := True
+//            if(indexOf(stage) != 0) stages(indexOf(stage) - 1).arbitration.flushAll := True
             stage.arbitration.removeIt := True
             exceptionValids(stageId) := True
-//            when(!exceptionValidsRegs.takeRight(stages.length-stageId-1).fold(False)(_ || _)) {
+            when(!exceptionValidsRegs.takeRight(stages.length-stageId-1).fold(False)(_ || _)) {
-            exceptionContext := port.payload
+              exceptionContext := port.payload
-//            }
+            }
           }
         }
+
         for(stageId <- firstStageIndexWithExceptionPort until stages.length; stage = stages(stageId) ){
           when(stage.arbitration.isFlushed){
             exceptionValids(stageId) := False
@@ -436,6 +432,12 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
           }otherwise{
             exceptionValidsRegs(stageId) := exceptionValids(stageId)
           }
+
+          if(stageId != 0){
+            when(exceptionValidsRegs(stageId)){
+              stages(stageId-1).arbitration.haltByOther := True
+            }
+          }
         }
       } else null
 
@@ -489,23 +491,15 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
       //Interrupt/Exception entry logic
       pipelineLiberator.enable setWhen(interrupt)
 
-//      if(exceptionPortCtrl != null) {
-//        when(exception) {
-//          exceptionPortCtrl.exceptionValidsRegs.foreach(_ := False)
-//        }
-//      }
       when(exception || (interrupt && pipelineLiberator.done)){
         jumpInterface.valid := True
         jumpInterface.payload := mtvec
-        memory.arbitration.flushAll := True //Mouai
+        memory.arbitration.flushAll := True
+        if(exceptionPortCtrl != null) exceptionPortCtrl.exceptionValidsRegs.last := False
         mstatus.MIE  := False
         mstatus.MPIE := mstatus.MIE
         mstatus.MPP  := privilege
-        mepc := exception mux(
+        mepc := mepcCaptureStage.input(PC)
-          True  -> writeBack.input(PC),
-          False -> fetcher.nextPc()._2
-        )
-
         mcause.interrupt := interrupt
         mcause.exceptionCode := ((mip.MEIP && mie.MEIE) ? U(11) | ((mip.MSIP && mie.MSIE) ? U(3) | U(7)))
       }
@@ -517,12 +511,13 @@ class CsrPlugin(config : CsrPluginConfig) extends Plugin[VexRiscv] with Exceptio
 
 
       //Manage MRET instructions
-      when(memory.input(ENV_CTRL) === EnvCtrlEnum.MRET) {
+      when(execute.arbitration.isValid && execute.input(ENV_CTRL) === EnvCtrlEnum.MRET) {
-        memory.arbitration.haltItself := writeBack.arbitration.isValid
+        when(memory.arbitration.isValid || writeBack.arbitration.isValid){
-        when(memory.arbitration.isFiring) {
+          execute.arbitration.haltItself := True
+        } otherwise {
           jumpInterface.valid := True
           jumpInterface.payload := mepc
-          execute.arbitration.flushAll := True
+          decode.arbitration.flushAll := True
           mstatus.MIE := mstatus.MPIE
           privilege := mstatus.MPP
         }

src/main/scala/vexriscv/plugin/Fetcher.scala

@@ -8,6 +8,9 @@ import StreamVexPimper._
 import scala.collection.mutable.ArrayBuffer
 
 
+//TODO val killLastStage = jump.pcLoad.valid || decode.arbitration.isRemoved
+// DBUSSimple check memory halt execute optimization
+
 abstract class IBusFetcherImpl(val catchAccessFault : Boolean,
                                val resetVector : BigInt,
                                val keepPcPlus4 : Boolean,
@@ -28,9 +31,8 @@ abstract class IBusFetcherImpl(val catchAccessFault : Boolean,
   assert(!(cmdToRspStageCount == 1 && !injectorStage))
   assert(!(compressedGen && !decodePcGen))
   var fetcherHalt : Bool = null
-  lazy val decodeNextPcValid = Bool //TODO remove me ?
+  lazy val pcValids = Vec(Bool, 4)
-  lazy val decodeNextPc = UInt(32 bits)
+  def pcValid(stage : Stage) = pcValids(pipeline.indexOf(stage))
-  def nextPc() = (False, decodeNextPc)
   var incomingInstruction : Bool = null
   override def incoming() = incomingInstruction
 
@@ -303,16 +305,29 @@ abstract class IBusFetcherImpl(val catchAccessFault : Boolean,
         inputBeforeStage
       })
 
-      if (decodePcGen) {
-        decodeNextPcValid := True
-        decodeNextPc := decodePc.pcReg
-      } else {
-        val lastStageStream = if (injectorStage) inputBeforeStage
-        else if (cmdToRspStageCount > 1) iBusRsp.inputPipeline(cmdToRspStageCount - 2)
-        else throw new Exception("Fetch should at least have two stages")
 
-        decodeNextPcValid := RegNext(lastStageStream.isStall)
+      def pcUpdatedGen(input : Bool, stucks : Seq[Bool], relaxedInput : Boolean) : Seq[Bool] = {
-        decodeNextPc := decode.input(PC)
+        stucks.scanLeft(input)((i, stuck) => {
+          val reg = RegInit(False)
+          if(!relaxedInput) when(flush) {
+            reg := False
+          }
+          when(!stuck) {
+            reg := i
+          }
+          if(relaxedInput || i != input) when(flush) {
+            reg := False
+          }
+          reg
+        }).tail
+      }
+
+      val nextPcCalc = if (decodePcGen) {
+        val valids = pcUpdatedGen(True, List(execute, memory, writeBack).map(_.arbitration.isStuck), true)
+        pcValids := Vec(valids.takeRight(4))
+      } else new Area{
+        val valids = pcUpdatedGen(True, iBusRsp.inputPipeline.map(!_.ready) ++ (if (injectorStage) List(!decodeInput.ready) else Nil) ++ List(execute, memory, writeBack).map(_.arbitration.isStuck), relaxedPcCalculation)
+        pcValids := Vec(valids.takeRight(4))
       }
 
       decodeInput.ready := !decode.arbitration.isStuck

src/test/cpp/regression/.gitignore

@@ -1 +1,2 @@
 *.regTraceRef
+/freertos.gtkw

src/test/cpp/regression/main.cpp

@@ -1734,7 +1734,7 @@ string riscvTestDiv[] = {
 };
 
 string freeRtosTests[] = {
-		"AltBlock", "AltQTest", "AltPollQ", "blocktim", "countsem", "dead", "EventGroupsDemo", "flop", "integer", "QPeek",
+		"AltQTest", "AltBlock",  "AltPollQ", "blocktim", "countsem", "dead", "EventGroupsDemo", "flop", "integer", "QPeek",
 		"QueueSet", "recmutex", "semtest", "TaskNotify", "BlockQ", "crhook", "dynamic",
 		"GenQTest", "PollQ", "QueueOverwrite", "QueueSetPolling", "sp_flop", "test1"
 		 //"flop", "sp_flop" // <- Simple test

src/test/python/tool/disasm.s

@@ -1 +1 @@
-.word 0x3c12083
+.word 0x34129073