/*************************************************************************************** * Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences * Copyright (c) 2020-2021 Peng Cheng Laboratory * * XiangShan is licensed under Mulan PSL v2. * You can use this software according to the terms and conditions of the Mulan PSL v2. * You may obtain a copy of Mulan PSL v2 at: * http://license.coscl.org.cn/MulanPSL2 * * THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND, * EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT, * MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE. * * See the Mulan PSL v2 for more details. ***************************************************************************************/ package xiangshan.frontend import chisel3._ import chisel3.util._ import freechips.rocketchip.rocket.ExpandedInstruction import freechips.rocketchip.rocket.RVCDecoder import org.chipsalliance.cde.config.Parameters import utility._ import utils._ import xiangshan._ import xiangshan.backend.decode.isa.predecode.PreDecodeInst import xiangshan.backend.fu.NewCSR.TriggerUtil import xiangshan.backend.fu.util.SdtrigExt import xiangshan.frontend.icache._ trait HasPdConst extends HasXSParameter with HasICacheParameters with HasIFUConst { def isRVC(inst: UInt) = inst(1, 0) =/= 3.U def isLink(reg: UInt) = reg === 1.U || reg === 5.U def brInfo(instr: UInt) = { val brType :: Nil = ListLookup(instr, List(BrType.notCFI), PreDecodeInst.brTable) val rd = Mux(isRVC(instr), instr(12), instr(11, 7)) val rs = Mux(isRVC(instr), Mux(brType === BrType.jal, 0.U, instr(11, 7)), instr(19, 15)) val isCall = (brType === BrType.jal && !isRVC(instr) || brType === BrType.jalr) && isLink(rd) // Only for RV64 val isRet = brType === BrType.jalr && isLink(rs) && !isCall List(brType, isCall, isRet) } def jal_offset(inst: UInt, rvc: Bool): UInt = { val rvc_offset = Cat(inst(12), inst(8), inst(10, 9), inst(6), inst(7), inst(2), inst(11), inst(5, 3), 0.U(1.W)) val rvi_offset = Cat(inst(31), inst(19, 12), inst(20), inst(30, 21), 0.U(1.W)) val max_width = rvi_offset.getWidth SignExt(Mux(rvc, SignExt(rvc_offset, max_width), SignExt(rvi_offset, max_width)), XLEN) } def br_offset(inst: UInt, rvc: Bool): UInt = { val rvc_offset = Cat(inst(12), inst(6, 5), inst(2), inst(11, 10), inst(4, 3), 0.U(1.W)) val rvi_offset = Cat(inst(31), inst(7), inst(30, 25), inst(11, 8), 0.U(1.W)) val max_width = rvi_offset.getWidth SignExt(Mux(rvc, SignExt(rvc_offset, max_width), SignExt(rvi_offset, max_width)), XLEN) } def NOP = "h4501".U(16.W) } object BrType { def notCFI = "b00".U def branch = "b01".U def jal = "b10".U def jalr = "b11".U def apply() = UInt(2.W) } object ExcType { // TODO:add exctype def notExc = "b000".U def apply() = UInt(3.W) } class PreDecodeInfo extends Bundle { // 8 bit val valid = Bool() val isRVC = Bool() val brType = UInt(2.W) val isCall = Bool() val isRet = Bool() // val excType = UInt(3.W) def isBr = brType === BrType.branch def isJal = brType === BrType.jal def isJalr = brType === BrType.jalr def notCFI = brType === BrType.notCFI } class PreDecodeResp(implicit p: Parameters) extends XSBundle with HasPdConst { val pd = Vec(PredictWidth, new PreDecodeInfo) val hasHalfValid = Vec(PredictWidth, Bool()) // val expInstr = Vec(PredictWidth, UInt(32.W)) val instr = Vec(PredictWidth, UInt(32.W)) val jumpOffset = Vec(PredictWidth, UInt(XLEN.W)) // val hasLastHalf = Bool() val triggered = Vec(PredictWidth, TriggerAction()) } class PreDecode(implicit p: Parameters) extends XSModule with HasPdConst { val io = IO(new Bundle() { val in = Input(ValidIO(new IfuToPreDecode)) val out = Output(new PreDecodeResp) }) val data = io.in.bits.data // val lastHalfMatch = io.in.lastHalfMatch val validStart, validEnd = Wire(Vec(PredictWidth, Bool())) val h_validStart, h_validEnd = Wire(Vec(PredictWidth, Bool())) val validStart_half, validEnd_half = Wire(Vec(PredictWidth, Bool())) val h_validStart_half, h_validEnd_half = Wire(Vec(PredictWidth, Bool())) val validStart_halfPlus1, validEnd_halfPlus1 = Wire(Vec(PredictWidth, Bool())) val h_validStart_halfPlus1, h_validEnd_halfPlus1 = Wire(Vec(PredictWidth, Bool())) val validStart_diff, validEnd_diff = Wire(Vec(PredictWidth, Bool())) val h_validStart_diff, h_validEnd_diff = Wire(Vec(PredictWidth, Bool())) val currentIsRVC = Wire(Vec(PredictWidth, Bool())) validStart_half.map(_ := false.B) validEnd_half.map(_ := false.B) h_validStart_half.map(_ := false.B) h_validEnd_half.map(_ := false.B) validStart_halfPlus1.map(_ := false.B) validEnd_halfPlus1.map(_ := false.B) h_validStart_halfPlus1.map(_ := false.B) h_validEnd_halfPlus1.map(_ := false.B) val rawInsts = if (HasCExtension) VecInit((0 until PredictWidth).map(i => Cat(data(i + 1), data(i)))) else VecInit((0 until PredictWidth).map(i => data(i))) for (i <- 0 until PredictWidth) { val inst = WireInit(rawInsts(i)) // val expander = Module(new RVCExpander) currentIsRVC(i) := isRVC(inst) val currentPC = io.in.bits.pc(i) // expander.io.in := inst val brType :: isCall :: isRet :: Nil = brInfo(inst) val jalOffset = jal_offset(inst, currentIsRVC(i)) val brOffset = br_offset(inst, currentIsRVC(i)) io.out.hasHalfValid(i) := h_validStart(i) io.out.triggered(i) := DontCare // VecInit(Seq.fill(10)(false.B)) io.out.pd(i).valid := validStart(i) io.out.pd(i).isRVC := currentIsRVC(i) // for diff purpose only io.out.pd(i).brType := brType io.out.pd(i).isCall := isCall io.out.pd(i).isRet := isRet // io.out.expInstr(i) := expander.io.out.bits io.out.instr(i) := inst io.out.jumpOffset(i) := Mux(io.out.pd(i).isBr, brOffset, jalOffset) } // the first half is always reliable for (i <- 0 until PredictWidth / 2) { val lastIsValidEnd = if (i == 0) { true.B } else { validEnd(i - 1) || !HasCExtension.B } validStart(i) := (lastIsValidEnd || !HasCExtension.B) validEnd(i) := validStart(i) && currentIsRVC(i) || !validStart(i) || !HasCExtension.B // prepared for last half match val h_lastIsValidEnd = if (i == 0) { false.B } else { h_validEnd(i - 1) || !HasCExtension.B } h_validStart(i) := (h_lastIsValidEnd || !HasCExtension.B) h_validEnd(i) := h_validStart(i) && currentIsRVC(i) || !h_validStart(i) || !HasCExtension.B } for (i <- 0 until PredictWidth) { val lastIsValidEnd = if (i == 0) { true.B } else { validEnd_diff(i - 1) || !HasCExtension.B } validStart_diff(i) := (lastIsValidEnd || !HasCExtension.B) validEnd_diff(i) := validStart_diff(i) && currentIsRVC(i) || !validStart_diff(i) || !HasCExtension.B // prepared for last half match val h_lastIsValidEnd = if (i == 0) { false.B } else { h_validEnd_diff(i - 1) || !HasCExtension.B } h_validStart_diff(i) := (h_lastIsValidEnd || !HasCExtension.B) h_validEnd_diff(i) := h_validStart_diff(i) && currentIsRVC(i) || !h_validStart_diff(i) || !HasCExtension.B } // assume PredictWidth / 2 is a valid start for (i <- PredictWidth / 2 until PredictWidth) { val lastIsValidEnd = if (i == PredictWidth / 2) { true.B } else { validEnd_half(i - 1) || !HasCExtension.B } validStart_half(i) := (lastIsValidEnd || !HasCExtension.B) validEnd_half(i) := validStart_half(i) && currentIsRVC(i) || !validStart_half(i) || !HasCExtension.B // prepared for last half match val h_lastIsValidEnd = if (i == PredictWidth / 2) { true.B } else { h_validEnd_half(i - 1) || !HasCExtension.B } h_validStart_half(i) := (h_lastIsValidEnd || !HasCExtension.B) h_validEnd_half(i) := h_validStart_half(i) && currentIsRVC(i) || !h_validStart_half(i) || !HasCExtension.B } // assume PredictWidth / 2 + 1 is a valid start (and PredictWidth / 2 is last half of RVI) for (i <- PredictWidth / 2 + 1 until PredictWidth) { val lastIsValidEnd = if (i == PredictWidth / 2 + 1) { true.B } else { validEnd_halfPlus1(i - 1) || !HasCExtension.B } validStart_halfPlus1(i) := (lastIsValidEnd || !HasCExtension.B) validEnd_halfPlus1(i) := validStart_halfPlus1(i) && currentIsRVC(i) || !validStart_halfPlus1(i) || !HasCExtension.B // prepared for last half match val h_lastIsValidEnd = if (i == PredictWidth / 2 + 1) { true.B } else { h_validEnd_halfPlus1(i - 1) || !HasCExtension.B } h_validStart_halfPlus1(i) := (h_lastIsValidEnd || !HasCExtension.B) h_validEnd_halfPlus1(i) := h_validStart_halfPlus1(i) && currentIsRVC(i) || !h_validStart_halfPlus1( i ) || !HasCExtension.B } validStart_halfPlus1(PredictWidth / 2) := false.B // could be true but when true we select half, not halfPlus1 validEnd_halfPlus1(PredictWidth / 2) := true.B // assume h_PredictWidth / 2 is an end h_validStart_halfPlus1(PredictWidth / 2) := false.B // could be true but when true we select half, not halfPlus1 h_validEnd_halfPlus1(PredictWidth / 2) := true.B // if PredictWidth / 2 - 1 is a valid end, PredictWidth / 2 is a valid start for (i <- PredictWidth / 2 until PredictWidth) { validStart(i) := Mux(validEnd(PredictWidth / 2 - 1), validStart_half(i), validStart_halfPlus1(i)) validEnd(i) := Mux(validEnd(PredictWidth / 2 - 1), validEnd_half(i), validEnd_halfPlus1(i)) h_validStart(i) := Mux(h_validEnd(PredictWidth / 2 - 1), h_validStart_half(i), h_validStart_halfPlus1(i)) h_validEnd(i) := Mux(h_validEnd(PredictWidth / 2 - 1), h_validEnd_half(i), h_validEnd_halfPlus1(i)) } val validStartMismatch = Wire(Bool()) val validEndMismatch = Wire(Bool()) val validH_ValidStartMismatch = Wire(Bool()) val validH_ValidEndMismatch = Wire(Bool()) validStartMismatch := validStart.zip(validStart_diff).map { case (a, b) => a =/= b }.reduce(_ || _) validEndMismatch := validEnd.zip(validEnd_diff).map { case (a, b) => a =/= b }.reduce(_ || _) validH_ValidStartMismatch := h_validStart.zip(h_validStart_diff).map { case (a, b) => a =/= b }.reduce(_ || _) validH_ValidEndMismatch := h_validEnd.zip(h_validEnd_diff).map { case (a, b) => a =/= b }.reduce(_ || _) XSError(io.in.valid && validStartMismatch, p"validStart mismatch\n") XSError(io.in.valid && validEndMismatch, p"validEnd mismatch\n") XSError(io.in.valid && validH_ValidStartMismatch, p"h_validStart mismatch\n") XSError(io.in.valid && validH_ValidEndMismatch, p"h_validEnd mismatch\n") // io.out.hasLastHalf := !io.out.pd(PredictWidth - 1).isRVC && io.out.pd(PredictWidth - 1).valid for (i <- 0 until PredictWidth) { XSDebug( true.B, p"instr ${Hexadecimal(io.out.instr(i))}, " + p"validStart ${Binary(validStart(i))}, " + p"validEnd ${Binary(validEnd(i))}, " + p"isRVC ${Binary(io.out.pd(i).isRVC)}, " + p"brType ${Binary(io.out.pd(i).brType)}, " + p"isRet ${Binary(io.out.pd(i).isRet)}, " + p"isCall ${Binary(io.out.pd(i).isCall)}\n" ) } } class IfuToF3PreDecode(implicit p: Parameters) extends XSBundle with HasPdConst { val instr = Vec(PredictWidth, UInt(32.W)) } class F3PreDecodeResp(implicit p: Parameters) extends XSBundle with HasPdConst { val pd = Vec(PredictWidth, new PreDecodeInfo) } class F3Predecoder(implicit p: Parameters) extends XSModule with HasPdConst { val io = IO(new Bundle() { val in = Input(new IfuToF3PreDecode) val out = Output(new F3PreDecodeResp) }) io.out.pd.zipWithIndex.map { case (pd, i) => pd.valid := DontCare pd.isRVC := DontCare pd.brType := brInfo(io.in.instr(i))(0) pd.isCall := brInfo(io.in.instr(i))(1) pd.isRet := brInfo(io.in.instr(i))(2) } } class RVCExpander(implicit p: Parameters) extends XSModule { val io = IO(new Bundle { val in = Input(UInt(32.W)) val fsIsOff = Input(Bool()) val out = Output(new ExpandedInstruction) val ill = Output(Bool()) }) val decoder = new RVCDecoder(io.in, io.fsIsOff, XLEN, fLen, useAddiForMv = true) if (HasCExtension) { io.out := decoder.decode io.ill := decoder.ill } else { io.out := decoder.passthrough io.ill := false.B } } /* --------------------------------------------------------------------- * Predict result check * * --------------------------------------------------------------------- */ object FaultType { def noFault = "b000".U def jalFault = "b001".U // not CFI taken or invalid instruction taken def retFault = "b010".U // not CFI taken or invalid instruction taken def targetFault = "b011".U def notCFIFault = "b100".U // not CFI taken or invalid instruction taken def invalidTaken = "b101".U def jalrFault = "b110".U def apply() = UInt(3.W) } class CheckInfo extends Bundle { // 8 bit val value = UInt(3.W) def isjalFault = value === FaultType.jalFault def isjalrFault = value === FaultType.jalrFault def isRetFault = value === FaultType.retFault def istargetFault = value === FaultType.targetFault def invalidTakenFault = value === FaultType.invalidTaken def notCFIFault = value === FaultType.notCFIFault } class PredCheckerResp(implicit p: Parameters) extends XSBundle with HasPdConst { // to Ibuffer write port (stage 1) val stage1Out = new Bundle { val fixedRange = Vec(PredictWidth, Bool()) val fixedTaken = Vec(PredictWidth, Bool()) } // to Ftq write back port (stage 2) val stage2Out = new Bundle { val fixedTarget = Vec(PredictWidth, UInt(VAddrBits.W)) val jalTarget = Vec(PredictWidth, UInt(VAddrBits.W)) val fixedMissPred = Vec(PredictWidth, Bool()) val faultType = Vec(PredictWidth, new CheckInfo) } } class PredChecker(implicit p: Parameters) extends XSModule with HasPdConst { val io = IO(new Bundle { val in = Input(new IfuToPredChecker) val out = Output(new PredCheckerResp) }) val (takenIdx, predTaken) = (io.in.ftqOffset.bits, io.in.ftqOffset.valid) val predTarget = io.in.target val (instrRange, instrValid) = (io.in.instrRange, io.in.instrValid) val (pds, pc, jumpOffset) = (io.in.pds, io.in.pc, io.in.jumpOffset) val jalFaultVec, jalrFaultVec, retFaultVec, targetFault, notCFITaken, invalidTaken = Wire(Vec(PredictWidth, Bool())) /** remask fault may appear together with other faults, but other faults are exclusive * so other f ault mast use fixed mask to keep only one fault would be found and redirect to Ftq * we first detecct remask fault and then use fixedRange to do second check **/ // Stage 1: detect remask fault /** first check: remask Fault */ jalFaultVec := VecInit(pds.zipWithIndex.map { case (pd, i) => pd.isJal && instrRange(i) && instrValid(i) && (takenIdx > i.U && predTaken || !predTaken) }) jalrFaultVec := VecInit(pds.zipWithIndex.map { case (pd, i) => pd.isJalr && !pd.isRet && instrRange(i) && instrValid(i) && (takenIdx > i.U && predTaken || !predTaken) }) retFaultVec := VecInit(pds.zipWithIndex.map { case (pd, i) => pd.isRet && instrRange(i) && instrValid(i) && (takenIdx > i.U && predTaken || !predTaken) }) val remaskFault = VecInit((0 until PredictWidth).map(i => jalFaultVec(i) || jalrFaultVec(i) || retFaultVec(i))) val remaskIdx = ParallelPriorityEncoder(remaskFault.asUInt) val needRemask = ParallelOR(remaskFault) val fixedRange = instrRange.asUInt & (Fill(PredictWidth, !needRemask) | Fill(PredictWidth, 1.U(1.W)) >> ~remaskIdx) require( isPow2(PredictWidth), "If PredictWidth does not satisfy the power of 2," + "expression: Fill(PredictWidth, 1.U(1.W)) >> ~remaskIdx is not right !!" ) io.out.stage1Out.fixedRange := fixedRange.asTypeOf(Vec(PredictWidth, Bool())) io.out.stage1Out.fixedTaken := VecInit(pds.zipWithIndex.map { case (pd, i) => instrValid(i) && fixedRange(i) && (pd.isRet || pd.isJal || takenIdx === i.U && predTaken && !pd.notCFI) }) /** second check: faulse prediction fault and target fault */ notCFITaken := VecInit(pds.zipWithIndex.map { case (pd, i) => fixedRange(i) && instrValid(i) && i.U === takenIdx && pd.notCFI && predTaken }) invalidTaken := VecInit(pds.zipWithIndex.map { case (pd, i) => fixedRange(i) && !instrValid(i) && i.U === takenIdx && predTaken }) val jumpTargets = VecInit(pds.zipWithIndex.map { case (pd, i) => (pc(i) + jumpOffset(i)).asTypeOf(UInt(VAddrBits.W)) }) val seqTargets = VecInit((0 until PredictWidth).map(i => pc(i) + Mux(pds(i).isRVC || !instrValid(i), 2.U, 4.U))) // Stage 2: detect target fault /** target calculation: in the next stage */ val fixedRangeNext = RegEnable(fixedRange, io.in.fire_in) val instrValidNext = RegEnable(instrValid, io.in.fire_in) val takenIdxNext = RegEnable(takenIdx, io.in.fire_in) val predTakenNext = RegEnable(predTaken, io.in.fire_in) val predTargetNext = RegEnable(predTarget, io.in.fire_in) val jumpTargetsNext = RegEnable(jumpTargets, io.in.fire_in) val seqTargetsNext = RegEnable(seqTargets, io.in.fire_in) val pdsNext = RegEnable(pds, io.in.fire_in) val jalFaultVecNext = RegEnable(jalFaultVec, io.in.fire_in) val jalrFaultVecNext = RegEnable(jalrFaultVec, io.in.fire_in) val retFaultVecNext = RegEnable(retFaultVec, io.in.fire_in) val notCFITakenNext = RegEnable(notCFITaken, io.in.fire_in) val invalidTakenNext = RegEnable(invalidTaken, io.in.fire_in) targetFault := VecInit(pdsNext.zipWithIndex.map { case (pd, i) => fixedRangeNext(i) && instrValidNext( i ) && (pd.isJal || pd.isBr) && takenIdxNext === i.U && predTakenNext && (predTargetNext =/= jumpTargetsNext(i)) }) io.out.stage2Out.faultType.zipWithIndex.foreach { case (faultType, i) => faultType.value := MuxCase( FaultType.noFault, Seq( jalFaultVecNext(i) -> FaultType.jalFault, jalrFaultVecNext(i) -> FaultType.jalrFault, retFaultVecNext(i) -> FaultType.retFault, targetFault(i) -> FaultType.targetFault, notCFITakenNext(i) -> FaultType.notCFIFault, invalidTakenNext(i) -> FaultType.invalidTaken ) ) } io.out.stage2Out.fixedMissPred.zipWithIndex.foreach { case (missPred, i) => missPred := jalFaultVecNext(i) || jalrFaultVecNext(i) || retFaultVecNext(i) || notCFITakenNext(i) || invalidTakenNext(i) || targetFault(i) } io.out.stage2Out.fixedTarget.zipWithIndex.foreach { case (target, i) => target := Mux(jalFaultVecNext(i) || targetFault(i), jumpTargetsNext(i), seqTargetsNext(i)) } io.out.stage2Out.jalTarget.zipWithIndex.foreach { case (target, i) => target := jumpTargetsNext(i) } } class FrontendTrigger(implicit p: Parameters) extends XSModule with SdtrigExt { val io = IO(new Bundle() { val frontendTrigger = Input(new FrontendTdataDistributeIO) val triggered = Output(Vec(PredictWidth, TriggerAction())) val pds = Input(Vec(PredictWidth, new PreDecodeInfo)) val pc = Input(Vec(PredictWidth, UInt(VAddrBits.W))) val data = if (HasCExtension) Input(Vec(PredictWidth + 1, UInt(16.W))) else Input(Vec(PredictWidth, UInt(32.W))) }) val data = io.data val rawInsts = if (HasCExtension) VecInit((0 until PredictWidth).map(i => Cat(data(i + 1), data(i)))) else VecInit((0 until PredictWidth).map(i => data(i))) val tdataVec = RegInit(VecInit(Seq.fill(TriggerNum)(0.U.asTypeOf(new MatchTriggerIO)))) when(io.frontendTrigger.tUpdate.valid) { tdataVec(io.frontendTrigger.tUpdate.bits.addr) := io.frontendTrigger.tUpdate.bits.tdata } val triggerEnableVec = RegInit(VecInit(Seq.fill(TriggerNum)(false.B))) // From CSR, controlled by priv mode, etc. triggerEnableVec := io.frontendTrigger.tEnableVec XSDebug(triggerEnableVec.asUInt.orR, "Debug Mode: At least one frontend trigger is enabled\n") val triggerTimingVec = VecInit(tdataVec.map(_.timing)) val triggerChainVec = VecInit(tdataVec.map(_.chain)) for (i <- 0 until TriggerNum) { PrintTriggerInfo(triggerEnableVec(i), tdataVec(i)) } val debugMode = io.frontendTrigger.debugMode val triggerCanRaiseBpExp = io.frontendTrigger.triggerCanRaiseBpExp // val triggerHitVec = Wire(Vec(PredictWidth, Vec(TriggerNum, Bool()))) val triggerHitVec = (0 until TriggerNum).map(j => TriggerCmpConsecutive(io.pc, tdataVec(j).tdata2, tdataVec(j).matchType, triggerEnableVec(j)).map(hit => hit && !tdataVec(j).select && !debugMode ) ).transpose for (i <- 0 until PredictWidth) { val triggerCanFireVec = Wire(Vec(TriggerNum, Bool())) TriggerCheckCanFire(TriggerNum, triggerCanFireVec, VecInit(triggerHitVec(i)), triggerTimingVec, triggerChainVec) val actionVec = VecInit(tdataVec.map(_.action)) val triggerAction = Wire(TriggerAction()) TriggerUtil.triggerActionGen(triggerAction, triggerCanFireVec, actionVec, triggerCanRaiseBpExp) // Priority may select last when no trigger fire. io.triggered(i) := triggerAction XSDebug( triggerCanFireVec.asUInt.orR, p"Debug Mode: Predecode Inst No. ${i} has trigger action vec ${triggerCanFireVec.asUInt.orR}\n" ) } }