xref: /XiangShan/src/main/scala/xiangshan/backend/fu/NewCSR/CSREvents/MretEvent.scala (revision 6808b8030a5ec6cf43824f1d575b050426f1c427)
1package xiangshan.backend.fu.NewCSR.CSREvents
2
3import chisel3._
4import chisel3.util._
5import org.chipsalliance.cde.config.Parameters
6import utility.{SignExt, ZeroExt}
7import xiangshan.ExceptionNO
8import xiangshan.ExceptionNO._
9import xiangshan.backend.fu.NewCSR.CSRBundles.{CauseBundle, OneFieldBundle, PrivState}
10import xiangshan.backend.fu.NewCSR.CSRConfig.{VaddrMaxWidth, XLEN}
11import xiangshan.backend.fu.NewCSR.CSRDefines.{HgatpMode, PrivMode, SatpMode, VirtMode}
12import xiangshan.backend.fu.NewCSR._
13import xiangshan.AddrTransType
14
15
16class MretEventOutput extends Bundle with EventUpdatePrivStateOutput with EventOutputBase {
17  val mstatus  = ValidIO((new MstatusBundle).addInEvent(_.MPP, _.MPV, _.MIE, _.MPIE, _.MPRV, _.MDT, _.SDT))
18  val vsstatus = ValidIO((new SstatusBundle).addInEvent(_.SDT))
19  val targetPc = ValidIO(new TargetPCBundle)
20}
21
22class MretEventInput extends Bundle {
23  val mstatus  = Input(new MstatusBundle)
24  val vsstatus = Input(new SstatusBundle)
25  val mepc     = Input(new Epc())
26  val satp     = Input(new SatpBundle)
27  val vsatp    = Input(new SatpBundle)
28  val hgatp    = Input(new HgatpBundle)
29}
30
31class MretEventModule(implicit p: Parameters) extends Module with CSREventBase {
32  val in = IO(new MretEventInput)
33  val out = IO(new MretEventOutput)
34
35  private val satp = in.satp
36  private val vsatp = in.vsatp
37  private val hgatp = in.hgatp
38  private val nextPrivState = out.privState.bits
39
40  private val instrAddrTransType = AddrTransType(
41    bare = nextPrivState.isModeM ||
42           (!nextPrivState.isVirtual && satp.MODE === SatpMode.Bare) ||
43           (nextPrivState.isVirtual && vsatp.MODE === SatpMode.Bare && hgatp.MODE === HgatpMode.Bare),
44    sv39 = !nextPrivState.isModeM && !nextPrivState.isVirtual && satp.MODE === SatpMode.Sv39 ||
45           nextPrivState.isVirtual && vsatp.MODE === SatpMode.Sv39,
46    sv48 = !nextPrivState.isModeM && !nextPrivState.isVirtual && satp.MODE === SatpMode.Sv48 ||
47           nextPrivState.isVirtual && vsatp.MODE === SatpMode.Sv48,
48    sv39x4 = nextPrivState.isVirtual && vsatp.MODE === SatpMode.Bare && hgatp.MODE === HgatpMode.Sv39x4,
49    sv48x4 = nextPrivState.isVirtual && vsatp.MODE === SatpMode.Bare && hgatp.MODE === HgatpMode.Sv48x4
50  )
51  val outPrivState   = Wire(new PrivState)
52  outPrivState.PRVM := in.mstatus.MPP
53  outPrivState.V    := Mux(in.mstatus.MPP === PrivMode.M, VirtMode.Off.asUInt, in.mstatus.MPV.asUInt)
54
55  val mretToM  = outPrivState.isModeM
56  val mretToS  = outPrivState.isModeHS
57  val mretToVu = outPrivState.isModeVU
58
59  out := DontCare
60
61  out.privState.valid := valid
62  out.mstatus  .valid := valid
63  out.targetPc .valid := valid
64
65  out.privState.bits          := outPrivState
66  out.mstatus.bits.MPP        := PrivMode.U
67  out.mstatus.bits.MPV        := VirtMode.Off.asUInt
68  out.mstatus.bits.MIE        := in.mstatus.MPIE
69  out.mstatus.bits.MPIE       := 1.U
70  out.mstatus.bits.MPRV       := Mux(in.mstatus.MPP =/= PrivMode.M, 0.U, in.mstatus.MPRV.asUInt)
71  // clear MDT when return mret always execute in M mode
72  out.mstatus.bits.MDT    := 0.U
73  // clear sstatus.SDT when return mode below M and HS
74  out.mstatus.bits.SDT    := Mux(mretToM || mretToS, in.mstatus.SDT.asBool, 0.U)
75  // clear vsstatus.SDT when return to VU
76  out.vsstatus.bits.SDT   := Mux(mretToVu, 0.U, in.vsstatus.SDT.asBool)
77
78  out.targetPc.bits.pc        := in.mepc.asUInt
79  out.targetPc.bits.raiseIPF  := instrAddrTransType.checkPageFault(in.mepc.asUInt)
80  out.targetPc.bits.raiseIAF  := instrAddrTransType.checkAccessFault(in.mepc.asUInt)
81  out.targetPc.bits.raiseIGPF := instrAddrTransType.checkGuestPageFault(in.mepc.asUInt)
82}
83
84trait MretEventSinkBundle extends EventSinkBundle { self: CSRModule[_ <: CSRBundle] =>
85  val retFromM = IO(Flipped(new MretEventOutput))
86
87  addUpdateBundleInCSREnumType(retFromM.getBundleByName(self.modName.toLowerCase()))
88
89  reconnectReg()
90}
91