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rocket-chip/src/main/scala/rocket/CSR.scala
2017-05-07 15:40:08 -07:00

798 lines
29 KiB
Scala

// See LICENSE.SiFive for license details.
// See LICENSE.Berkeley for license details.
package rocket
import collection.mutable.LinkedHashMap
import Chisel._
import Instructions._
import config._
import tile._
import uncore.devices._
import util._
import Chisel.ImplicitConversions._
class MStatus extends Bundle {
// not truly part of mstatus, but convenient
val debug = Bool()
val isa = UInt(width = 32)
val dprv = UInt(width = PRV.SZ) // effective privilege for data accesses
val prv = UInt(width = PRV.SZ) // not truly part of mstatus, but convenient
val sd = Bool()
val zero2 = UInt(width = 27)
val sxl = UInt(width = 2)
val uxl = UInt(width = 2)
val sd_rv32 = Bool()
val zero1 = UInt(width = 8)
val tsr = Bool()
val tw = Bool()
val tvm = Bool()
val mxr = Bool()
val sum = Bool()
val mprv = Bool()
val xs = UInt(width = 2)
val fs = UInt(width = 2)
val mpp = UInt(width = 2)
val hpp = UInt(width = 2)
val spp = UInt(width = 1)
val mpie = Bool()
val hpie = Bool()
val spie = Bool()
val upie = Bool()
val mie = Bool()
val hie = Bool()
val sie = Bool()
val uie = Bool()
}
class DCSR extends Bundle {
val xdebugver = UInt(width = 2)
val zero4 = UInt(width=2)
val zero3 = UInt(width = 12)
val ebreakm = Bool()
val ebreakh = Bool()
val ebreaks = Bool()
val ebreaku = Bool()
val zero2 = Bool()
val stopcycle = Bool()
val stoptime = Bool()
val cause = UInt(width = 3)
// TODO: debugint is not in the Debug Spec v13
val debugint = Bool()
val zero1 = UInt(width=2)
val step = Bool()
val prv = UInt(width = PRV.SZ)
}
class MIP(implicit p: Parameters) extends CoreBundle()(p)
with HasRocketCoreParameters {
val lip = Vec(coreParams.nLocalInterrupts, Bool())
val zero2 = Bool()
val debug = Bool() // keep in sync with CSR.debugIntCause
val zero1 = Bool()
val rocc = Bool()
val meip = Bool()
val heip = Bool()
val seip = Bool()
val ueip = Bool()
val mtip = Bool()
val htip = Bool()
val stip = Bool()
val utip = Bool()
val msip = Bool()
val hsip = Bool()
val ssip = Bool()
val usip = Bool()
}
class PTBR(implicit p: Parameters) extends CoreBundle()(p) {
def pgLevelsToMode(i: Int) = (xLen, i) match {
case (32, 2) => 1
case (64, x) if x >= 3 && x <= 6 => x + 5
}
val (modeBits, maxASIdBits) = xLen match {
case 32 => (1, 9)
case 64 => (4, 16)
}
require(modeBits + maxASIdBits + maxPAddrBits - pgIdxBits == xLen)
val mode = UInt(width = modeBits)
val asid = UInt(width = maxASIdBits)
val ppn = UInt(width = maxPAddrBits - pgIdxBits)
}
object PRV
{
val SZ = 2
val U = 0
val S = 1
val H = 2
val M = 3
}
object CSR
{
// commands
val SZ = 3
def X = BitPat.dontCare(SZ)
def N = UInt(0,SZ)
def W = UInt(1,SZ)
def S = UInt(2,SZ)
def C = UInt(3,SZ)
def I = UInt(4,SZ)
def R = UInt(5,SZ)
val ADDRSZ = 12
def debugIntCause = 14 // keep in sync with MIP.debug
def debugTriggerCause = {
val res = debugIntCause
require(!(Causes.all contains res))
res
}
val firstCtr = CSRs.cycle
val firstCtrH = CSRs.cycleh
val firstHPC = CSRs.hpmcounter3
val firstHPCH = CSRs.hpmcounter3h
val firstHPE = CSRs.mhpmevent3
val firstMHPC = CSRs.mhpmcounter3
val firstMHPCH = CSRs.mhpmcounter3h
val firstHPM = 3
val nCtr = 32
val nHPM = nCtr - firstHPM
val maxPMPs = 16
}
class PerfCounterIO(implicit p: Parameters) extends CoreBundle
with HasRocketCoreParameters {
val eventSel = UInt(OUTPUT, xLen)
val inc = UInt(INPUT, log2Ceil(1+retireWidth))
}
class CSRFileIO(implicit p: Parameters) extends CoreBundle
with HasRocketCoreParameters {
val interrupts = new TileInterrupts().asInput
val hartid = UInt(INPUT, hartIdLen)
val rw = new Bundle {
val addr = UInt(INPUT, CSR.ADDRSZ)
val cmd = Bits(INPUT, CSR.SZ)
val rdata = Bits(OUTPUT, xLen)
val wdata = Bits(INPUT, xLen)
}
val decode = new Bundle {
val csr = UInt(INPUT, CSR.ADDRSZ)
val fp_illegal = Bool(OUTPUT)
val rocc_illegal = Bool(OUTPUT)
val read_illegal = Bool(OUTPUT)
val write_illegal = Bool(OUTPUT)
val write_flush = Bool(OUTPUT)
val system_illegal = Bool(OUTPUT)
}
val csr_stall = Bool(OUTPUT)
val eret = Bool(OUTPUT)
val singleStep = Bool(OUTPUT)
val status = new MStatus().asOutput
val ptbr = new PTBR().asOutput
val evec = UInt(OUTPUT, vaddrBitsExtended)
val exception = Bool(INPUT)
val retire = UInt(INPUT, log2Up(1+retireWidth))
val custom_mrw_csrs = Vec(nCustomMrwCsrs, UInt(INPUT, xLen))
val cause = UInt(INPUT, xLen)
val pc = UInt(INPUT, vaddrBitsExtended)
val badaddr = UInt(INPUT, vaddrBitsExtended)
val time = UInt(OUTPUT, xLen)
val fcsr_rm = Bits(OUTPUT, FPConstants.RM_SZ)
val fcsr_flags = Valid(Bits(width = FPConstants.FLAGS_SZ)).flip
val rocc_interrupt = Bool(INPUT)
val interrupt = Bool(OUTPUT)
val interrupt_cause = UInt(OUTPUT, xLen)
val bp = Vec(nBreakpoints, new BP).asOutput
val pmp = Vec(nPMPs, new PMP).asOutput
val counters = Vec(nPerfCounters, new PerfCounterIO)
}
class CSRFile(perfEventSets: EventSets = new EventSets(Seq()))(implicit p: Parameters) extends CoreModule()(p)
with HasRocketCoreParameters {
val io = new CSRFileIO
val reset_mstatus = Wire(init=new MStatus().fromBits(0))
reset_mstatus.mpp := PRV.M
reset_mstatus.prv := PRV.M
val reg_mstatus = Reg(init=reset_mstatus)
val new_prv = Wire(init = reg_mstatus.prv)
reg_mstatus.prv := legalizePrivilege(new_prv)
val reset_dcsr = Wire(init=new DCSR().fromBits(0))
reset_dcsr.xdebugver := 1
reset_dcsr.prv := PRV.M
val reg_dcsr = Reg(init=reset_dcsr)
val (supported_interrupts, delegable_interrupts) = {
val sup = Wire(new MIP)
sup.usip := false
sup.ssip := Bool(usingVM)
sup.hsip := false
sup.msip := true
sup.utip := false
sup.stip := Bool(usingVM)
sup.htip := false
sup.mtip := true
sup.ueip := false
sup.seip := Bool(usingVM)
sup.heip := false
sup.meip := true
sup.rocc := usingRoCC
sup.zero1 := false
sup.debug := false
sup.zero2 := false
sup.lip foreach { _ := true }
val del = Wire(init=sup)
del.msip := false
del.mtip := false
del.meip := false
(sup.asUInt, del.asUInt)
}
val delegable_exceptions = UInt(Seq(
Causes.misaligned_fetch,
Causes.fetch_page_fault,
Causes.breakpoint,
Causes.load_page_fault,
Causes.store_page_fault,
Causes.user_ecall).map(1 << _).sum)
val reg_debug = Reg(init=Bool(false))
val reg_dpc = Reg(UInt(width = vaddrBitsExtended))
val reg_dscratch = Reg(UInt(width = xLen))
val reg_singleStepped = Reg(Bool())
val reg_tselect = Reg(UInt(width = log2Up(nBreakpoints)))
val reg_bp = Reg(Vec(1 << log2Up(nBreakpoints), new BP))
val reg_pmp = Reg(Vec(nPMPs, new PMPReg))
val reg_mie = Reg(UInt(width = xLen))
val reg_mideleg = Reg(UInt(width = xLen))
val reg_medeleg = Reg(UInt(width = xLen))
val reg_mip = Reg(new MIP)
val reg_mepc = Reg(UInt(width = vaddrBitsExtended))
val reg_mcause = Reg(Bits(width = xLen))
val reg_mbadaddr = Reg(UInt(width = vaddrBitsExtended))
val reg_mscratch = Reg(Bits(width = xLen))
val mtvecWidth = paddrBits min xLen
val reg_mtvec = mtvecInit match {
case Some(addr) => Reg(init=UInt(addr, mtvecWidth))
case None => Reg(UInt(width = mtvecWidth))
}
val reg_mcounteren = Reg(UInt(width = 32))
val reg_scounteren = Reg(UInt(width = 32))
val delegable_counters = (BigInt(1) << (nPerfCounters + CSR.firstHPM)) - 1
val reg_sepc = Reg(UInt(width = vaddrBitsExtended))
val reg_scause = Reg(Bits(width = xLen))
val reg_sbadaddr = Reg(UInt(width = vaddrBitsExtended))
val reg_sscratch = Reg(Bits(width = xLen))
val reg_stvec = Reg(UInt(width = vaddrBits))
val reg_sptbr = Reg(new PTBR)
val reg_wfi = Reg(init=Bool(false))
val reg_fflags = Reg(UInt(width = 5))
val reg_frm = Reg(UInt(width = 3))
val reg_instret = WideCounter(64, io.retire)
val reg_cycle = if (enableCommitLog) reg_instret else WideCounter(64)
val reg_hpmevent = io.counters.map(c => Reg(init = UInt(0, xLen)))
(io.counters zip reg_hpmevent) foreach { case (c, e) => c.eventSel := e }
val reg_hpmcounter = io.counters.map(c => WideCounter(40, c.inc, reset = false))
val hpm_mask = reg_mcounteren & Mux((!usingVM).B || reg_mstatus.prv === PRV.S, delegable_counters.U, reg_scounteren)
val mip = Wire(init=reg_mip)
// seip is the OR of reg_mip.seip and the actual line from the PLIC
io.interrupts.seip.foreach { mip.seip := reg_mip.seip || RegNext(_) }
mip.rocc := io.rocc_interrupt
val read_mip = mip.asUInt & supported_interrupts
val pending_interrupts = read_mip & reg_mie
val m_interrupts = Mux(reg_mstatus.prv <= PRV.S || (reg_mstatus.prv === PRV.M && reg_mstatus.mie), pending_interrupts & ~reg_mideleg, UInt(0))
val s_interrupts = Mux(m_interrupts === 0 && (reg_mstatus.prv < PRV.S || (reg_mstatus.prv === PRV.S && reg_mstatus.sie)), pending_interrupts & reg_mideleg, UInt(0))
val (anyInterrupt, whichInterrupt) = chooseInterrupt(Seq(s_interrupts, m_interrupts))
val interruptMSB = BigInt(1) << (xLen-1)
val interruptCause = UInt(interruptMSB) + whichInterrupt
io.interrupt := anyInterrupt && !reg_debug && !io.singleStep || reg_singleStepped
io.interrupt_cause := interruptCause
io.bp := reg_bp take nBreakpoints
io.pmp := reg_pmp.map(PMP(_))
// debug interrupts are only masked by being in debug mode
when (Bool(usingDebug) && reg_dcsr.debugint && !reg_debug) {
io.interrupt := true
io.interrupt_cause := UInt(interruptMSB) + CSR.debugIntCause
}
val isaMaskString =
(if (usingMulDiv) "M" else "") +
(if (usingAtomics) "A" else "") +
(if (usingFPU) "F" else "") +
(if (usingFPU && xLen > 32) "D" else "") +
(if (usingCompressed) "C" else "") +
(if (usingRoCC) "X" else "")
val isaString = "I" + isaMaskString +
(if (usingVM) "S" else "") +
(if (usingUser) "U" else "")
val isaMax = (BigInt(log2Ceil(xLen) - 4) << (xLen-2)) | isaStringToMask(isaString)
val reg_misa = Reg(init=UInt(isaMax))
val read_mstatus = io.status.asUInt()(xLen-1,0)
val read_mapping = LinkedHashMap[Int,Bits](
CSRs.tselect -> reg_tselect,
CSRs.tdata1 -> reg_bp(reg_tselect).control.asUInt,
CSRs.tdata2 -> reg_bp(reg_tselect).address.sextTo(xLen),
CSRs.mimpid -> UInt(0),
CSRs.marchid -> UInt(0),
CSRs.mvendorid -> UInt(0),
CSRs.mcycle -> reg_cycle,
CSRs.minstret -> reg_instret,
CSRs.misa -> reg_misa,
CSRs.mstatus -> read_mstatus,
CSRs.mtvec -> reg_mtvec,
CSRs.mip -> read_mip,
CSRs.mie -> reg_mie,
CSRs.mscratch -> reg_mscratch,
CSRs.mepc -> reg_mepc.sextTo(xLen),
CSRs.mbadaddr -> reg_mbadaddr.sextTo(xLen),
CSRs.mcause -> reg_mcause,
CSRs.mhartid -> io.hartid)
val debug_csrs = LinkedHashMap[Int,Bits](
CSRs.dcsr -> reg_dcsr.asUInt,
CSRs.dpc -> reg_dpc.asUInt,
CSRs.dscratch -> reg_dscratch.asUInt)
val fp_csrs = LinkedHashMap[Int,Bits](
CSRs.fflags -> reg_fflags,
CSRs.frm -> reg_frm,
CSRs.fcsr -> Cat(reg_frm, reg_fflags))
if (usingDebug)
read_mapping ++= debug_csrs
if (usingFPU)
read_mapping ++= fp_csrs
for (((e, c), i) <- (reg_hpmevent.padTo(CSR.nHPM, UInt(0))
zip reg_hpmcounter.map(x => x: UInt).padTo(CSR.nHPM, UInt(0))) zipWithIndex) {
read_mapping += (i + CSR.firstHPE) -> e // mhpmeventN
read_mapping += (i + CSR.firstMHPC) -> c // mhpmcounterN
if (usingUser) read_mapping += (i + CSR.firstHPC) -> c // hpmcounterN
if (xLen == 32) {
read_mapping += (i + CSR.firstMHPCH) -> c // mhpmcounterNh
if (usingUser) read_mapping += (i + CSR.firstHPCH) -> c // hpmcounterNh
}
}
if (usingVM) {
val read_sie = reg_mie & reg_mideleg
val read_sip = read_mip & reg_mideleg
val read_sstatus = Wire(init = 0.U.asTypeOf(new MStatus))
read_sstatus.sd := io.status.sd
read_sstatus.uxl := io.status.uxl
read_sstatus.sd_rv32 := io.status.sd_rv32
read_sstatus.mxr := io.status.mxr
read_sstatus.sum := io.status.sum
read_sstatus.xs := io.status.xs
read_sstatus.fs := io.status.fs
read_sstatus.spp := io.status.spp
read_sstatus.spie := io.status.spie
read_sstatus.sie := io.status.sie
read_mapping += CSRs.sstatus -> (read_sstatus.asUInt())(xLen-1,0)
read_mapping += CSRs.sip -> read_sip.asUInt
read_mapping += CSRs.sie -> read_sie.asUInt
read_mapping += CSRs.sscratch -> reg_sscratch
read_mapping += CSRs.scause -> reg_scause
read_mapping += CSRs.sbadaddr -> reg_sbadaddr.sextTo(xLen)
read_mapping += CSRs.sptbr -> reg_sptbr.asUInt
read_mapping += CSRs.sepc -> reg_sepc.sextTo(xLen)
read_mapping += CSRs.stvec -> reg_stvec.sextTo(xLen)
read_mapping += CSRs.scounteren -> reg_scounteren
read_mapping += CSRs.mideleg -> reg_mideleg
read_mapping += CSRs.medeleg -> reg_medeleg
}
if (usingUser) {
read_mapping += CSRs.mcounteren -> reg_mcounteren
read_mapping += CSRs.cycle -> reg_cycle
read_mapping += CSRs.instret -> reg_instret
}
if (xLen == 32) {
read_mapping += CSRs.mcycleh -> (reg_cycle >> 32)
read_mapping += CSRs.minstreth -> (reg_instret >> 32)
if (usingUser) {
read_mapping += CSRs.cycleh -> (reg_cycle >> 32)
read_mapping += CSRs.instreth -> (reg_instret >> 32)
}
}
val pmpCfgPerCSR = xLen / new PMPConfig().getWidth
def pmpCfgIndex(i: Int) = (xLen / 32) * (i / pmpCfgPerCSR)
if (reg_pmp.nonEmpty) {
require(reg_pmp.size <= CSR.maxPMPs)
val read_pmp = reg_pmp.padTo(CSR.maxPMPs, 0.U.asTypeOf(new PMP))
for (i <- 0 until read_pmp.size by pmpCfgPerCSR)
read_mapping += (CSRs.pmpcfg0 + pmpCfgIndex(i)) -> read_pmp.map(_.cfg).slice(i, i + pmpCfgPerCSR).asUInt
for ((pmp, i) <- read_pmp zipWithIndex)
read_mapping += (CSRs.pmpaddr0 + i) -> pmp.addr
}
for (i <- 0 until nCustomMrwCsrs) {
val addr = 0xff0 + i
require(addr < (1 << CSR.ADDRSZ))
require(!read_mapping.contains(addr), "custom MRW CSR address " + i + " is already in use")
read_mapping += addr -> io.custom_mrw_csrs(i)
}
val decoded_addr = read_mapping map { case (k, v) => k -> (io.rw.addr === k) }
val wdata = readModifyWriteCSR(io.rw.cmd, io.rw.rdata, io.rw.wdata)
val system_insn = io.rw.cmd === CSR.I
val opcode = UInt(1) << io.rw.addr(2,0)
val insn_call = system_insn && opcode(0)
val insn_break = system_insn && opcode(1)
val insn_ret = system_insn && opcode(2)
val insn_wfi = system_insn && opcode(5)
private def decodeAny(m: LinkedHashMap[Int,Bits]): Bool = m.map { case(k: Int, _: Bits) => io.decode.csr === k }.reduce(_||_)
val allow_wfi = Bool(!usingVM) || reg_mstatus.prv > PRV.S || !reg_mstatus.tw
val allow_sfence_vma = Bool(!usingVM) || reg_mstatus.prv > PRV.S || !reg_mstatus.tvm
val allow_sret = Bool(!usingVM) || reg_mstatus.prv > PRV.S || !reg_mstatus.tsr
io.decode.fp_illegal := io.status.fs === 0 || !reg_misa('f'-'a')
io.decode.rocc_illegal := io.status.xs === 0 || !reg_misa('x'-'a')
io.decode.read_illegal := reg_mstatus.prv < io.decode.csr(9,8) ||
!decodeAny(read_mapping) ||
io.decode.csr === CSRs.sptbr && !allow_sfence_vma ||
(io.decode.csr.inRange(CSR.firstCtr, CSR.firstCtr + CSR.nCtr) || io.decode.csr.inRange(CSR.firstCtrH, CSR.firstCtrH + CSR.nCtr)) && reg_mstatus.prv <= PRV.S && hpm_mask(io.decode.csr(log2Ceil(CSR.firstCtr)-1,0)) ||
Bool(usingDebug) && decodeAny(debug_csrs) && !reg_debug ||
Bool(usingFPU) && decodeAny(fp_csrs) && io.decode.fp_illegal
io.decode.write_illegal := io.decode.csr(11,10).andR
io.decode.write_flush := !(io.decode.csr >= CSRs.mscratch && io.decode.csr <= CSRs.mbadaddr || io.decode.csr >= CSRs.sscratch && io.decode.csr <= CSRs.sbadaddr)
io.decode.system_illegal := reg_mstatus.prv < io.decode.csr(9,8) ||
!io.decode.csr(5) && io.decode.csr(2) && !allow_wfi ||
!io.decode.csr(5) && io.decode.csr(1) && !allow_sret ||
io.decode.csr(5) && !allow_sfence_vma
val cause =
Mux(insn_call, reg_mstatus.prv + Causes.user_ecall,
Mux[UInt](insn_break, Causes.breakpoint, io.cause))
val cause_lsbs = cause(log2Up(xLen)-1,0)
val causeIsDebugInt = cause(xLen-1) && cause_lsbs === CSR.debugIntCause
val causeIsDebugTrigger = !cause(xLen-1) && cause_lsbs === CSR.debugTriggerCause
val causeIsDebugBreak = !cause(xLen-1) && insn_break && Cat(reg_dcsr.ebreakm, reg_dcsr.ebreakh, reg_dcsr.ebreaks, reg_dcsr.ebreaku)(reg_mstatus.prv)
val trapToDebug = Bool(usingDebug) && (reg_singleStepped || causeIsDebugInt || causeIsDebugTrigger || causeIsDebugBreak || reg_debug)
val debugTVec = Mux(reg_debug, Mux(insn_break, UInt(0x800), UInt(0x808)), UInt(0x800))
val delegate = Bool(usingVM) && reg_mstatus.prv <= PRV.S && Mux(cause(xLen-1), reg_mideleg(cause_lsbs), reg_medeleg(cause_lsbs))
val mtvecBaseAlign = 2
val mtvecInterruptAlign = log2Ceil(new MIP().getWidth)
val notDebugTVec = {
val base = Mux(delegate, reg_stvec.sextTo(vaddrBitsExtended), reg_mtvec)
val interruptOffset = cause(mtvecInterruptAlign-1, 0) << mtvecBaseAlign
val interruptVec = Cat(base >> (mtvecInterruptAlign + mtvecBaseAlign), interruptOffset)
Mux(base(0) && cause(cause.getWidth-1), interruptVec, base)
}
val tvec = Mux(trapToDebug, debugTVec, notDebugTVec)
io.evec := tvec
io.ptbr := reg_sptbr
io.eret := insn_call || insn_break || insn_ret
io.singleStep := reg_dcsr.step && !reg_debug
io.status := reg_mstatus
io.status.sd := io.status.fs.andR || io.status.xs.andR
io.status.debug := reg_debug
io.status.isa := reg_misa
io.status.uxl := (if (usingUser) log2Ceil(xLen) - 4 else 0)
io.status.sxl := (if (usingVM) log2Ceil(xLen) - 4 else 0)
io.status.dprv := Reg(next = Mux(reg_mstatus.mprv && !reg_debug, reg_mstatus.mpp, reg_mstatus.prv))
if (xLen == 32)
io.status.sd_rv32 := io.status.sd
val exception = insn_call || insn_break || io.exception
assert(PopCount(insn_ret :: insn_call :: insn_break :: io.exception :: Nil) <= 1, "these conditions must be mutually exclusive")
when (insn_wfi) { reg_wfi := true }
when (pending_interrupts.orR || exception) { reg_wfi := false }
assert(!reg_wfi || io.retire === UInt(0))
when (io.retire(0) || exception) { reg_singleStepped := true }
when (!io.singleStep) { reg_singleStepped := false }
assert(!io.singleStep || io.retire <= UInt(1))
assert(!reg_singleStepped || io.retire === UInt(0))
when (exception) {
val epc = ~(~io.pc | (coreInstBytes-1))
val write_badaddr = cause isOneOf (Causes.illegal_instruction, Causes.breakpoint,
Causes.misaligned_load, Causes.misaligned_store, Causes.misaligned_fetch,
Causes.load_access, Causes.store_access, Causes.fetch_access,
Causes.load_page_fault, Causes.store_page_fault, Causes.fetch_page_fault)
val badaddr_value = Mux(write_badaddr, io.badaddr, 0.U)
when (trapToDebug) {
when (!reg_debug) {
reg_debug := true
reg_dpc := epc
reg_dcsr.cause := Mux(reg_singleStepped, 4, Mux(causeIsDebugInt, 3, Mux[UInt](causeIsDebugTrigger, 2, 1)))
reg_dcsr.prv := trimPrivilege(reg_mstatus.prv)
new_prv := PRV.M
}
}.elsewhen (delegate) {
reg_sepc := formEPC(epc)
reg_scause := cause
reg_sbadaddr := badaddr_value
reg_mstatus.spie := reg_mstatus.sie
reg_mstatus.spp := reg_mstatus.prv
reg_mstatus.sie := false
new_prv := PRV.S
}.otherwise {
reg_mepc := formEPC(epc)
reg_mcause := cause
reg_mbadaddr := badaddr_value
reg_mstatus.mpie := reg_mstatus.mie
reg_mstatus.mpp := trimPrivilege(reg_mstatus.prv)
reg_mstatus.mie := false
new_prv := PRV.M
}
}
when (insn_ret) {
when (Bool(usingVM) && !io.rw.addr(9)) {
reg_mstatus.sie := reg_mstatus.spie
reg_mstatus.spie := true
reg_mstatus.spp := PRV.U
new_prv := reg_mstatus.spp
io.evec := reg_sepc
}.elsewhen (Bool(usingDebug) && io.rw.addr(10)) {
new_prv := reg_dcsr.prv
reg_debug := false
io.evec := reg_dpc
}.otherwise {
reg_mstatus.mie := reg_mstatus.mpie
reg_mstatus.mpie := true
reg_mstatus.mpp := legalizePrivilege(PRV.U)
new_prv := reg_mstatus.mpp
io.evec := reg_mepc
}
}
io.time := reg_cycle
io.csr_stall := reg_wfi
io.rw.rdata := Mux1H(for ((k, v) <- read_mapping) yield decoded_addr(k) -> v)
io.fcsr_rm := reg_frm
when (io.fcsr_flags.valid) {
reg_fflags := reg_fflags | io.fcsr_flags.bits
}
when (io.rw.cmd.isOneOf(CSR.S, CSR.C, CSR.W)) {
when (decoded_addr(CSRs.mstatus)) {
val new_mstatus = new MStatus().fromBits(wdata)
reg_mstatus.mie := new_mstatus.mie
reg_mstatus.mpie := new_mstatus.mpie
if (usingUser) {
reg_mstatus.mprv := new_mstatus.mprv
reg_mstatus.mpp := trimPrivilege(new_mstatus.mpp)
if (usingVM) {
reg_mstatus.mxr := new_mstatus.mxr
reg_mstatus.sum := new_mstatus.sum
reg_mstatus.spp := new_mstatus.spp
reg_mstatus.spie := new_mstatus.spie
reg_mstatus.sie := new_mstatus.sie
reg_mstatus.tw := new_mstatus.tw
reg_mstatus.tvm := new_mstatus.tvm
reg_mstatus.tsr := new_mstatus.tsr
}
}
if (usingVM || usingFPU) reg_mstatus.fs := Fill(2, new_mstatus.fs.orR)
if (usingRoCC) reg_mstatus.xs := Fill(2, new_mstatus.xs.orR)
}
when (decoded_addr(CSRs.misa)) {
val mask = UInt(isaStringToMask(isaMaskString), xLen)
val f = wdata('f' - 'a')
reg_misa := ~(~wdata | (!f << ('d' - 'a'))) & mask | reg_misa & ~mask
}
when (decoded_addr(CSRs.mip)) {
// MIP should be modified based on the value in reg_mip, not the value
// in read_mip, since read_mip.seip is the OR of reg_mip.seip and
// io.interrupts.seip. We don't want the value on the PLIC line to
// inadvertently be OR'd into read_mip.seip.
val new_mip = readModifyWriteCSR(io.rw.cmd, reg_mip.asUInt, io.rw.wdata).asTypeOf(new MIP)
if (usingVM) {
reg_mip.ssip := new_mip.ssip
reg_mip.stip := new_mip.stip
reg_mip.seip := new_mip.seip
}
}
when (decoded_addr(CSRs.mie)) { reg_mie := wdata & supported_interrupts }
when (decoded_addr(CSRs.mepc)) { reg_mepc := formEPC(wdata) }
when (decoded_addr(CSRs.mscratch)) { reg_mscratch := wdata }
if (mtvecWritable)
when (decoded_addr(CSRs.mtvec)) { reg_mtvec := ~(~wdata | 2.U | Mux(wdata(0), UInt(((BigInt(1) << mtvecInterruptAlign) - 1) << mtvecBaseAlign), 0.U)) }
when (decoded_addr(CSRs.mcause)) { reg_mcause := wdata & UInt((BigInt(1) << (xLen-1)) + 31) /* only implement 5 LSBs and MSB */ }
when (decoded_addr(CSRs.mbadaddr)) { reg_mbadaddr := wdata(vaddrBitsExtended-1,0) }
for (((e, c), i) <- (reg_hpmevent zip reg_hpmcounter) zipWithIndex) {
writeCounter(i + CSR.firstMHPC, c, wdata)
when (decoded_addr(i + CSR.firstHPE)) { e := perfEventSets.maskEventSelector(wdata) }
}
writeCounter(CSRs.mcycle, reg_cycle, wdata)
writeCounter(CSRs.minstret, reg_instret, wdata)
if (usingFPU) {
when (decoded_addr(CSRs.fflags)) { reg_fflags := wdata }
when (decoded_addr(CSRs.frm)) { reg_frm := wdata }
when (decoded_addr(CSRs.fcsr)) { reg_fflags := wdata; reg_frm := wdata >> reg_fflags.getWidth }
}
if (usingDebug) {
when (decoded_addr(CSRs.dcsr)) {
val new_dcsr = new DCSR().fromBits(wdata)
reg_dcsr.step := new_dcsr.step
reg_dcsr.ebreakm := new_dcsr.ebreakm
if (usingVM) reg_dcsr.ebreaks := new_dcsr.ebreaks
if (usingUser) reg_dcsr.ebreaku := new_dcsr.ebreaku
if (usingUser) reg_dcsr.prv := trimPrivilege(new_dcsr.prv)
}
when (decoded_addr(CSRs.dpc)) { reg_dpc := ~(~wdata | (coreInstBytes-1)) }
when (decoded_addr(CSRs.dscratch)) { reg_dscratch := wdata }
}
if (usingVM) {
when (decoded_addr(CSRs.sstatus)) {
val new_sstatus = new MStatus().fromBits(wdata)
reg_mstatus.sie := new_sstatus.sie
reg_mstatus.spie := new_sstatus.spie
reg_mstatus.spp := new_sstatus.spp
reg_mstatus.mxr := new_sstatus.mxr
reg_mstatus.sum := new_sstatus.sum
reg_mstatus.fs := Fill(2, new_sstatus.fs.orR) // even without an FPU
if (usingRoCC) reg_mstatus.xs := Fill(2, new_sstatus.xs.orR)
}
when (decoded_addr(CSRs.sip)) {
val new_sip = new MIP().fromBits(wdata)
reg_mip.ssip := new_sip.ssip
}
when (decoded_addr(CSRs.sptbr)) {
val new_sptbr = new PTBR().fromBits(wdata)
val valid_mode = new_sptbr.pgLevelsToMode(pgLevels)
when (new_sptbr.mode === 0) { reg_sptbr.mode := 0 }
when (new_sptbr.mode === valid_mode) { reg_sptbr.mode := valid_mode }
when (new_sptbr.mode === 0 || new_sptbr.mode === valid_mode) {
reg_sptbr.ppn := new_sptbr.ppn(ppnBits-1,0)
if (asIdBits > 0) reg_sptbr.asid := new_sptbr.asid(asIdBits-1,0)
}
}
when (decoded_addr(CSRs.sie)) { reg_mie := (reg_mie & ~reg_mideleg) | (wdata & reg_mideleg) }
when (decoded_addr(CSRs.sscratch)) { reg_sscratch := wdata }
when (decoded_addr(CSRs.sepc)) { reg_sepc := formEPC(wdata) }
when (decoded_addr(CSRs.stvec)) { reg_stvec := ~(~wdata | 2.U | Mux(wdata(0), UInt(((BigInt(1) << mtvecInterruptAlign) - 1) << mtvecBaseAlign), 0.U)) }
when (decoded_addr(CSRs.scause)) { reg_scause := wdata & UInt((BigInt(1) << (xLen-1)) + 31) /* only implement 5 LSBs and MSB */ }
when (decoded_addr(CSRs.sbadaddr)) { reg_sbadaddr := wdata(vaddrBitsExtended-1,0) }
when (decoded_addr(CSRs.mideleg)) { reg_mideleg := wdata & delegable_interrupts }
when (decoded_addr(CSRs.medeleg)) { reg_medeleg := wdata & delegable_exceptions }
when (decoded_addr(CSRs.scounteren)) { reg_scounteren := wdata & UInt(delegable_counters) }
}
if (usingUser) {
when (decoded_addr(CSRs.mcounteren)) { reg_mcounteren := wdata & UInt(delegable_counters) }
}
if (nBreakpoints > 0) {
when (decoded_addr(CSRs.tselect)) { reg_tselect := wdata }
val bp = reg_bp(reg_tselect)
when (!bp.control.dmode || reg_debug) {
when (decoded_addr(CSRs.tdata1)) {
val newBPC = new BPControl().fromBits(wdata)
val dMode = newBPC.dmode && reg_debug
bp.control := newBPC
bp.control.dmode := dMode
bp.control.action := dMode && newBPC.action
}
when (decoded_addr(CSRs.tdata2)) { bp.address := wdata }
}
}
if (reg_pmp.nonEmpty) for (((pmp, next), i) <- (reg_pmp zip (reg_pmp.tail :+ reg_pmp.last)) zipWithIndex) {
require(xLen % pmp.cfg.getWidth == 0)
when (decoded_addr(CSRs.pmpcfg0 + pmpCfgIndex(i)) && !pmp.cfgLocked) {
pmp.cfg := new PMPConfig().fromBits(wdata >> ((i * pmp.cfg.getWidth) % xLen))
}
when (decoded_addr(CSRs.pmpaddr0 + i) && !pmp.addrLocked(next)) {
pmp.addr := wdata
}
}
}
reg_mip.lip := (io.interrupts.lip: Seq[Bool])
reg_mip.mtip := io.interrupts.mtip
reg_mip.msip := io.interrupts.msip
reg_mip.meip := io.interrupts.meip
reg_dcsr.debugint := io.interrupts.debug
if (!usingVM) {
reg_mideleg := 0
reg_medeleg := 0
reg_scounteren := 0
}
if (!usingUser) {
reg_mcounteren := 0
}
reg_sptbr.asid := 0
if (nBreakpoints <= 1) reg_tselect := 0
if (nBreakpoints >= 1)
reg_bp(nBreakpoints-1).control.chain := false
for (bpc <- reg_bp map {_.control}) {
bpc.ttype := bpc.tType
bpc.maskmax := bpc.maskMax
bpc.reserved := 0
bpc.zero := 0
bpc.h := false
if (!usingVM) bpc.s := false
if (!usingUser) bpc.u := false
if (!usingVM && !usingUser) bpc.m := true
when (reset) {
bpc.action := false
bpc.dmode := false
bpc.r := false
bpc.w := false
bpc.x := false
}
}
for (bp <- reg_bp drop nBreakpoints)
bp := new BP().fromBits(0)
for (pmp <- reg_pmp) {
pmp.cfg.res := 0
when (reset) {
pmp.cfg.a := 0
pmp.cfg.l := 0
}
}
def chooseInterrupt(masks: Seq[UInt]) = {
// we can't simply choose the highest-numbered interrupt, because timer
// interrupts are in the wrong place in mip.
val timerMask = UInt(0xF0, xLen)
val masked = masks.map(m => Cat(m.padTo(xLen) & ~timerMask, m.padTo(xLen) & timerMask))
(masks.map(_.orR).reduce(_||_), Log2(masked.asUInt)(log2Ceil(xLen)-1, 0))
}
def readModifyWriteCSR(cmd: UInt, rdata: UInt, wdata: UInt) =
(Mux(cmd.isOneOf(CSR.S, CSR.C), rdata, UInt(0)) | wdata) & ~Mux(cmd === CSR.C, wdata, UInt(0))
def legalizePrivilege(priv: UInt): UInt =
if (usingVM) Mux(priv === PRV.H, PRV.U, priv)
else if (usingUser) Fill(2, priv(0))
else PRV.M
def trimPrivilege(priv: UInt): UInt =
if (usingVM) priv
else legalizePrivilege(priv)
def writeCounter(lo: Int, ctr: WideCounter, wdata: UInt) = {
if (xLen == 32) {
val hi = lo + CSRs.mcycleh - CSRs.mcycle
when (decoded_addr(lo)) { ctr := Cat(ctr(ctr.getWidth-1, 32), wdata) }
when (decoded_addr(hi)) { ctr := Cat(wdata(ctr.getWidth-33, 0), ctr(31, 0)) }
} else {
when (decoded_addr(lo)) { ctr := wdata(ctr.getWidth-1, 0) }
}
}
def formEPC(x: UInt) = ~(~x | Cat(!reg_misa('c'-'a'), UInt(1)))
def isaStringToMask(s: String) = s.map(x => 1 << (x - 'A')).reduce(_|_)
}