xref: /XiangShan/src/main/scala/xiangshan/cache/mmu/TLB.scala (revision dc597826530cb6803c2396d6ab0e5eb176b732e0)
1/***************************************************************************************
2* Copyright (c) 2020-2021 Institute of Computing Technology, Chinese Academy of Sciences
3* Copyright (c) 2020-2021 Peng Cheng Laboratory
4*
5* XiangShan is licensed under Mulan PSL v2.
6* You can use this software according to the terms and conditions of the Mulan PSL v2.
7* You may obtain a copy of Mulan PSL v2 at:
8*          http://license.coscl.org.cn/MulanPSL2
9*
10* THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, WITHOUT WARRANTIES OF ANY KIND,
11* EITHER EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO NON-INFRINGEMENT,
12* MERCHANTABILITY OR FIT FOR A PARTICULAR PURPOSE.
13*
14* See the Mulan PSL v2 for more details.
15***************************************************************************************/
16
17package xiangshan.cache.mmu
18
19import chipsalliance.rocketchip.config.Parameters
20import chisel3._
21import chisel3.util._
22import xiangshan._
23import utils._
24import xiangshan.backend.roq.RoqPtr
25import xiangshan.backend.fu.util.HasCSRConst
26
27class TLB(Width: Int, isDtlb: Boolean)(implicit p: Parameters) extends TlbModule with HasCSRConst{
28  val io = IO(new TlbIO(Width))
29
30  val req    = io.requestor.map(_.req)
31  val resp   = io.requestor.map(_.resp)
32  val ptw    = io.ptw
33
34  val sfence = io.sfence
35  val csr    = io.csr
36  val satp   = csr.satp
37  val priv   = csr.priv
38  val ifecth = if (isDtlb) false.B else true.B
39  val mode   = if (isDtlb) priv.dmode else priv.imode
40  // val vmEnable = satp.mode === 8.U // && (mode < ModeM) // FIXME: fix me when boot xv6/linux...
41  val vmEnable = if(EnbaleTlbDebug) (satp.mode === 8.U)
42                 else               (satp.mode === 8.U && (mode < ModeM))
43
44  val reqAddr = req.map(_.bits.vaddr.asTypeOf(vaBundle))
45  val cmd     = req.map(_.bits.cmd)
46  val valid   = req.map(_.valid)
47
48  def widthMapSeq[T <: Seq[Data]](f: Int => T) = (0 until Width).map(f)
49  def widthMap[T <: Data](f: Int => T) = (0 until Width).map(f)
50
51  // Normal page && Super page
52  val nv = RegInit(VecInit(Seq.fill(TlbEntrySize)(false.B)))
53  val nMeta = Module(new CAMTemplate(UInt(vpnLen.W), TlbEntrySize, Width + 1)).io
54  val nData = Reg(Vec(TlbEntrySize, new TlbData(false)))
55  val sv = RegInit(VecInit(Seq.fill(TlbSPEntrySize)(false.B)))
56  val sMeta = Reg(Vec(TlbSPEntrySize, new TlbSPMeta))
57  val sData = Reg(Vec(TlbSPEntrySize, new TlbData(true)))
58  val v = nv ++ sv
59  val data = nData ++ sData
60  val g = VecInit(data.map(_.perm.g))
61  val pf = VecInit(data.zip(v).map{ case(e, vi) => e.perm.pf & vi })
62
63  /**
64    * PTW refill
65    */
66  val refill = ptw.resp.fire() && !sfence.valid
67
68  val normalReplacer = if (isDtlb) Some("random") else Some("plru")
69  val superReplacer = if (isDtlb) Some("random") else Some("plru")
70  val nReplace = ReplacementPolicy.fromString(normalReplacer, TlbEntrySize)
71  val sReplace = ReplacementPolicy.fromString(superReplacer, TlbSPEntrySize)
72  val nRefillIdx = replaceWrapper(nv, nReplace.way)
73  val sRefillIdx = replaceWrapper(sv, sReplace.way)
74
75  nMeta.w := DontCare
76  nMeta.w.valid := false.B
77  when (refill) {
78    val resp = ptw.resp.bits
79    when (resp.entry.level.getOrElse(0.U) === 2.U) {
80      val refillIdx = nRefillIdx
81      refillIdx.suggestName(s"NormalRefillIdx")
82
83      nv(refillIdx) := true.B
84      nMeta.w.bits.index := nRefillIdx
85      nMeta.w.bits.data  := resp.entry.tag
86      nMeta.w.valid := true.B
87      nData(refillIdx).apply(
88        ppn   = resp.entry.ppn,
89        level = resp.entry.level.getOrElse(0.U),
90        perm  = VecInit(resp.entry.perm.getOrElse(0.U)).asUInt,
91        pf    = resp.pf
92      )
93      nReplace.access(nRefillIdx)
94      XSDebug(p"Refill normal: idx:${refillIdx} entry:${resp.entry} pf:${resp.pf}\n")
95    }.otherwise {
96      val refillIdx = sRefillIdx
97      refillIdx.suggestName(s"SuperRefillIdx")
98
99      val dup = Cat(sv.zip(sMeta).map{ case (v, m) =>
100        v && m.hit(resp.entry.tag)
101      }).orR // NOTE: may have long latency, RegNext it
102
103      when (!dup) {
104        sv(refillIdx) := true.B
105        sMeta(refillIdx).apply(
106          vpn = resp.entry.tag,
107          level = resp.entry.level.getOrElse(0.U)
108        )
109        sData(refillIdx).apply(
110          ppn   = resp.entry.ppn,
111          level = resp.entry.level.getOrElse(0.U),
112          perm  = VecInit(resp.entry.perm.getOrElse(0.U)).asUInt,
113          pf    = resp.pf
114        )
115        sReplace.access(sRefillIdx)
116        XSDebug(p"Refill superpage: idx:${refillIdx} entry:${resp.entry} pf:${resp.pf}\n")
117      }
118    }
119  }
120
121  /**
122    * L1 TLB read
123    */
124  val sfenceVpn = sfence.bits.addr.asTypeOf(vaBundle).vpn
125  for (i <- 0 until Width) {
126    nMeta.r.req(i) := io.requestor(i).req.bits.vaddr.asTypeOf(vaBundle).vpn
127  }
128  nMeta.r.req(Width) := sfenceVpn
129
130  val nRefillMask = Mux(refill, UIntToOH(nRefillIdx)(TlbEntrySize-1, 0), 0.U).asBools
131  val sRefillMask = Mux(refill, UIntToOH(sRefillIdx)(TlbSPEntrySize-1, 0), 0.U).asBools
132  def TLBNormalRead(i: Int) = {
133    val entryHitVec = (
134      if (isDtlb)
135        VecInit(nMeta.r.resp(i).zip(nRefillMask).map{ case (e, m) => ~m && e } ++
136                sMeta.zip(sRefillMask).map{ case (e,m) => ~m && e.hit(reqAddr(i).vpn) })
137      else
138        VecInit(nMeta.r.resp(i) ++ sMeta.map(_.hit(reqAddr(i).vpn/*, satp.asid*/)))
139    )
140
141    val reqAddrReg = if (isDtlb) RegNext(reqAddr(i)) else reqAddr(i)
142    val cmdReg = if (isDtlb) RegNext(cmd(i)) else cmd(i)
143    val validReg = if (isDtlb) RegNext(valid(i)) else valid(i)
144    val entryHitVecReg = if (isDtlb) RegNext(entryHitVec) else entryHitVec
145    entryHitVecReg.suggestName(s"entryHitVecReg_${i}")
146
147    /***************** next cycle when two cycle is need********************/
148
149    val hitVec  = VecInit((v zip entryHitVecReg).map{ case (a,b) => a&b })
150    val pfHitVec   = VecInit((pf zip entryHitVecReg).map{ case (a,b) => a&b })
151    val pfArray = ParallelOR(pfHitVec).asBool && validReg && vmEnable
152    val hit     = ParallelOR(hitVec).asBool && validReg && vmEnable && ~pfArray
153    val miss    = !hit && validReg && vmEnable && ~pfArray
154    val hitppn  = ParallelMux(hitVec zip data.map(_.genPPN(reqAddrReg.vpn)))
155    val hitPerm = ParallelMux(hitVec zip data.map(_.perm))
156
157    hitVec.suggestName(s"hitVec_${i}")
158    pfHitVec.suggestName(s"pfHitVec_${i}")
159    hit.suggestName(s"hit_${i}")
160    miss.suggestName(s"miss_${i}")
161    hitppn.suggestName(s"hitppn_${i}")
162    hitPerm.suggestName(s"hitPerm_${i}")
163
164    XSDebug(valid(i), p"(${i.U}) entryHit:${Hexadecimal(entryHitVec.asUInt)}\n")
165    XSDebug(validReg, p"(${i.U}) entryHitReg:${Hexadecimal(entryHitVecReg.asUInt)} hitVec:${Hexadecimal(hitVec.asUInt)} pfHitVec:${Hexadecimal(pfHitVec.asUInt)} pfArray:${Hexadecimal(pfArray.asUInt)} hit:${hit} miss:${miss} hitppn:${Hexadecimal(hitppn)} hitPerm:${hitPerm}\n")
166
167    // resp  // TODO: A/D has not being concerned
168    val paddr = Cat(hitppn, reqAddrReg.off)
169    val vaddr = SignExt(req(i).bits.vaddr, PAddrBits)
170
171    req(i).ready := resp(i).ready
172    resp(i).valid := validReg
173    resp(i).bits.paddr := Mux(vmEnable, paddr, if (isDtlb) RegNext(vaddr) else vaddr)
174    resp(i).bits.miss := miss
175    resp(i).bits.ptwBack := io.ptw.resp.fire()
176
177    val perm = hitPerm // NOTE: given the excp, the out module choose one to use?
178    val update = hit && (!hitPerm.a || !hitPerm.d && TlbCmd.isWrite(cmdReg)) // update A/D through exception
179    val modeCheck = !(mode === ModeU && !perm.u || mode === ModeS && perm.u && (!priv.sum || ifecth))
180    val ldPf = (pfArray && TlbCmd.isRead(cmdReg) && true.B /*!isAMO*/) || hit && !(modeCheck && (perm.r || priv.mxr && perm.x)) && (TlbCmd.isRead(cmdReg) && true.B/*!isAMO*/) // TODO: handle isAMO
181    val stPf = (pfArray && TlbCmd.isWrite(cmdReg) || false.B /*isAMO*/ ) || hit && !(modeCheck && perm.w) && (TlbCmd.isWrite(cmdReg) || false.B/*TODO isAMO. */)
182    val instrPf = (pfArray && TlbCmd.isExec(cmdReg)) || hit && !(modeCheck && perm.x) && TlbCmd.isExec(cmdReg)
183    resp(i).bits.excp.pf.ld    := ldPf || update
184    resp(i).bits.excp.pf.st    := stPf || update
185    resp(i).bits.excp.pf.instr := instrPf || update
186
187    // if vmenable, use pre-calcuated pma check result
188    resp(i).bits.mmio := Mux(TlbCmd.isExec(cmdReg), !perm.pi, !perm.pd)
189    resp(i).bits.excp.af.ld    := Mux(TlbCmd.isAtom(cmdReg), !perm.pa, !perm.pr) && TlbCmd.isRead(cmdReg)
190    resp(i).bits.excp.af.st    := Mux(TlbCmd.isAtom(cmdReg), !perm.pa, !perm.pw) && TlbCmd.isWrite(cmdReg)
191    resp(i).bits.excp.af.instr := Mux(TlbCmd.isAtom(cmdReg), false.B, !perm.pe)
192
193    // if !vmenable, check pma
194    val (pmaMode, accessWidth) = AddressSpace.memmapAddrMatch(resp(i).bits.paddr)
195    when(!vmEnable){
196      resp(i).bits.mmio := Mux(TlbCmd.isExec(cmdReg), !PMAMode.icache(pmaMode), !PMAMode.dcache(pmaMode))
197      resp(i).bits.excp.af.ld    := Mux(TlbCmd.isAtom(cmdReg), !PMAMode.atomic(pmaMode), !PMAMode.read(pmaMode)) && TlbCmd.isRead(cmdReg)
198      resp(i).bits.excp.af.st    := Mux(TlbCmd.isAtom(cmdReg), !PMAMode.atomic(pmaMode), !PMAMode.write(pmaMode)) && TlbCmd.isWrite(cmdReg)
199      resp(i).bits.excp.af.instr := Mux(TlbCmd.isAtom(cmdReg), false.B, !PMAMode.execute(pmaMode))
200    }
201
202    // TODO: MMIO check
203
204    (hit, miss, hitVec, validReg)
205  }
206
207  val readResult = (0 until Width).map(TLBNormalRead(_))
208  val hitVec = readResult.map(res => res._1)
209  val missVec = readResult.map(res => res._2)
210  val hitVecVec = readResult.map(res => res._3)
211  val validRegVec = readResult.map(res => res._4)
212
213  // replacement
214  def get_access_index(one_hot: UInt): Valid[UInt] = {
215    val res = Wire(Valid(UInt(log2Up(one_hot.getWidth).W)))
216    res.valid := Cat(one_hot).orR
217    res.bits := OHToUInt(one_hot)
218    res
219  }
220  def get_access(one_hot: Seq[Bool], stop: Int, start: Int): Valid[UInt] = {
221    val tmp = VecInit(one_hot).asUInt
222    get_access_index(tmp(stop, start))
223  }
224  val nAccess = hitVecVec.map(a => get_access(a, TlbEntrySize - 1, 0))
225  val sAccess = hitVecVec.map(a => get_access(a, TlbEntrySize + TlbSPEntrySize - 1, TlbEntrySize))
226  if (Width == 1) {
227    when (nAccess(0).valid) { nReplace.access(nAccess(0).bits) }
228    when (sAccess(0).valid) { sReplace.access(sAccess(0).bits) }
229  } else {
230    nReplace.access(nAccess)
231    sReplace.access(sAccess)
232  }
233
234  for (i <- 0 until Width) {
235    io.ptw.req(i).valid := validRegVec(i) && missVec(i) && !RegNext(refill)
236    io.ptw.req(i).bits.vpn := RegNext(reqAddr(i).vpn)
237  }
238  io.ptw.resp.ready := true.B
239
240  // val tooManyPf = PopCount(pf) > 5.U
241  // when (tooManyPf) { // when too much pf, just clear
242  //   XSDebug(p"Too many pf just flush all the pf v:${Hexadecimal(VecInit(v).asUInt)} pf:${Hexadecimal(pf.asUInt)}\n")
243  //   v.zipWithIndex.map{ case (a, i) => a := a & !pf(i) }
244  // }
245
246  // sfence (flush)
247  val sfenceHit = nMeta.r.resp(Width) ++ sMeta.map(_.hit(sfenceVpn))
248  when (sfence.valid) {
249    when (sfence.bits.rs1) { // virtual address *.rs1 <- (rs1===0.U)
250      when (sfence.bits.rs2) { // asid, but i do not want to support asid, *.rs2 <- (rs2===0.U)
251        // all addr and all asid
252        v.map(_ := false.B)
253      }.otherwise {
254        // all addr but specific asid
255        v.zipWithIndex.map{ case (a,i) => a := a & g(i) }
256      }
257    }.otherwise {
258      when (sfence.bits.rs2) {
259        // specific addr but all asid
260        v.zipWithIndex.map{ case (a,i) => a := a & !sfenceHit(i) }
261      }.otherwise {
262        // specific addr and specific asid
263        v.zipWithIndex.map{ case (a,i) => a := a & !sfenceHit(i) && !g(i) }
264      }
265    }
266  }
267
268  if (isDtlb) {
269    for (i <- 0 until Width) {
270      XSPerfAccumulate("first_access" + Integer.toString(i, 10), validRegVec(i) && vmEnable && RegNext(req(i).bits.debug.isFirstIssue))
271      XSPerfAccumulate("access" + Integer.toString(i, 10), validRegVec(i) && vmEnable)
272    }
273    for (i <- 0 until Width) {
274      XSPerfAccumulate("first_miss" + Integer.toString(i, 10), validRegVec(i) && vmEnable && missVec(i) && RegNext(req(i).bits.debug.isFirstIssue))
275      XSPerfAccumulate("miss" + Integer.toString(i, 10), validRegVec(i) && vmEnable && missVec(i))
276    }
277  } else {
278    // NOTE: ITLB is blocked, so every resp will be valid only when hit
279    // every req will be ready only when hit
280    XSPerfAccumulate("access", io.requestor(0).req.fire() && vmEnable)
281    XSPerfAccumulate("miss", ptw.req(0).fire())
282  }
283  //val reqCycleCnt = Reg(UInt(16.W))
284  //reqCycleCnt := reqCycleCnt + BoolStopWatch(ptw.req(0).fire(), ptw.resp.fire || sfence.valid)
285  //XSPerfAccumulate("ptw_req_count", ptw.req.fire())
286  //XSPerfAccumulate("ptw_req_cycle", Mux(ptw.resp.fire(), reqCycleCnt, 0.U))
287  XSPerfAccumulate("ptw_resp_count", ptw.resp.fire())
288  XSPerfAccumulate("ptw_resp_pf_count", ptw.resp.fire() && ptw.resp.bits.pf)
289  for (i <- 0 until TlbEntrySize) {
290    val indexHitVec = hitVecVec.zip(validRegVec).map{ case (h, v) => h(i) && v }
291    XSPerfAccumulate(s"NormalAccessIndex${i}", Mux(vmEnable, PopCount(indexHitVec), 0.U))
292  }
293  for (i <- 0 until TlbSPEntrySize) {
294    val indexHitVec = hitVecVec.zip(validRegVec).map{ case (h, v) => h(i + TlbEntrySize) && v }
295    XSPerfAccumulate(s"SuperAccessIndex${i}", Mux(vmEnable, PopCount(indexHitVec), 0.U))
296  }
297  for (i <- 0 until TlbEntrySize) {
298    XSPerfAccumulate(s"NormalRefillIndex${i}", refill && ptw.resp.bits.entry.level.getOrElse(0.U) === 2.U && i.U === nRefillIdx)
299  }
300  for (i <- 0 until TlbSPEntrySize) {
301    XSPerfAccumulate(s"SuperRefillIndex${i}", refill && ptw.resp.bits.entry.level.getOrElse(0.U) =/= 2.U && i.U === sRefillIdx)
302  }
303
304  // Log
305  for(i <- 0 until Width) {
306    XSDebug(req(i).valid, p"req(${i.U}): (${req(i).valid} ${req(i).ready}) ${req(i).bits}\n")
307    XSDebug(resp(i).valid, p"resp(${i.U}): (${resp(i).valid} ${resp(i).ready}) ${resp(i).bits}\n")
308  }
309
310  XSDebug(sfence.valid, p"Sfence: ${sfence}\n")
311  XSDebug(ParallelOR(valid)|| ptw.resp.valid, p"CSR: ${csr}\n")
312  XSDebug(ParallelOR(valid) || ptw.resp.valid, p"vmEnable:${vmEnable} hit:${Binary(VecInit(hitVec).asUInt)} miss:${Binary(VecInit(missVec).asUInt)} v:${Hexadecimal(VecInit(v).asUInt)} pf:${Hexadecimal(pf.asUInt)}\n")
313  for (i <- ptw.req.indices) {
314    XSDebug(ptw.req(i).fire(), p"PTW req:${ptw.req(i).bits}\n")
315  }
316  XSDebug(ptw.resp.valid, p"PTW resp:${ptw.resp.bits} (v:${ptw.resp.valid}r:${ptw.resp.ready}) \n")
317
318//   // NOTE: just for simple tlb debug, comment it after tlb's debug
319  // assert(!io.ptw.resp.valid || io.ptw.resp.bits.entry.tag === io.ptw.resp.bits.entry.ppn, "Simple tlb debug requires vpn === ppn")
320}
321
322object TLB {
323  def apply
324  (
325    in: Seq[BlockTlbRequestIO],
326    sfence: SfenceBundle,
327    csr: TlbCsrBundle,
328    width: Int,
329    isDtlb: Boolean,
330    shouldBlock: Boolean
331  )(implicit p: Parameters) = {
332    require(in.length == width)
333
334    val tlb = Module(new TLB(width, isDtlb))
335
336    tlb.io.sfence <> sfence
337    tlb.io.csr <> csr
338
339    if (!shouldBlock) { // dtlb
340      for (i <- 0 until width) {
341        tlb.io.requestor(i) <> in(i)
342        // tlb.io.requestor(i).req.valid := in(i).req.valid
343        // tlb.io.requestor(i).req.bits := in(i).req.bits
344        // in(i).req.ready := tlb.io.requestor(i).req.ready
345
346        // in(i).resp.valid := tlb.io.requestor(i).resp.valid
347        // in(i).resp.bits := tlb.io.requestor(i).resp.bits
348        // tlb.io.requestor(i).resp.ready := in(i).resp.ready
349      }
350    } else { // itlb
351      require(width == 1)
352      tlb.io.requestor(0).req.valid := in(0).req.valid
353      tlb.io.requestor(0).req.bits := in(0).req.bits
354      in(0).req.ready := !tlb.io.requestor(0).resp.bits.miss && in(0).resp.ready && tlb.io.requestor(0).req.ready
355
356      in(0).resp.valid := tlb.io.requestor(0).resp.valid && !tlb.io.requestor(0).resp.bits.miss
357      in(0).resp.bits := tlb.io.requestor(0).resp.bits
358      tlb.io.requestor(0).resp.ready := in(0).resp.ready
359    }
360
361    tlb.io.ptw
362  }
363}
364