Merge pull request #289 from buncram/expose-satp

Expose satp

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

@@ -82,6 +82,7 @@ case class CsrPluginConfig(
                             deterministicInteruptionEntry : Boolean = false, //Only used for simulatation purposes
                             wfiOutput           : Boolean = false,
                             withPrivilegedDebug : Boolean = false, //For the official RISC-V debug spec implementation
+                            exportPrivilege     : Boolean = false,
                             var debugTriggers       : Int     = 2
                           ){
   assert(!ucycleAccess.canWrite)
@@ -612,6 +613,7 @@ class CsrPlugin(val config: CsrPluginConfig) extends Plugin[VexRiscv] with Excep
     contextSwitching = Bool().setName("contextSwitching")
 
     privilege = UInt(2 bits).setName("CsrPlugin_privilege")
+    if (exportPrivilege) out(privilege)
     forceMachineWire = False
 
     if(catchIllegalAccess || ecallGen || withEbreak)

src/main/scala/vexriscv/plugin/MmuPlugin.scala

@@ -41,7 +41,9 @@ case class MmuPortConfig(portTlbSize : Int, latency : Int = 0, earlyRequireMmuLo
 class MmuPlugin(ioRange : UInt => Bool,
                 virtualRange : UInt => Bool = address => True,
 //                allowUserIo : Boolean = false,
-                enableMmuInMachineMode : Boolean = false) extends Plugin[VexRiscv] with MemoryTranslator {
+                enableMmuInMachineMode : Boolean = false,
+                exportSatp: Boolean = false
+                ) extends Plugin[VexRiscv] with MemoryTranslator {
 
   var dBusAccess : DBusAccess = null
   val portsInfo = ArrayBuffer[MmuPort]()
@@ -94,8 +96,10 @@ class MmuPlugin(ioRange : UInt => Bool,
       val satp = new Area {
         val mode = RegInit(False)
         val asid = Reg(Bits(9 bits))
-        // Bottom 20 bits are used in implementation, but top 2 bits are still stored for OS use.
-        val ppn = Reg(UInt(22 bits))
+        val ppn = Reg(UInt(22 bits)) // Bottom 20 bits are used in implementation, but top 2 bits are still stored for OS use.
+        if(exportSatp) {
+          out(mode, asid, ppn)
+        }
       }
 
       for(offset <- List(CSR.MSTATUS, CSR.SSTATUS)) csrService.rw(offset, 19 -> status.mxr, 18 -> status.sum, 17 -> status.mprv)