More WIP on PMP

src/main/scala/rocket/PMP.scala

@@ -17,31 +17,82 @@ class PMPConfig extends Bundle {
   val r = Bool()
 }
 
+object PMP {
+  def lgAlign = 2
+}
+
 class PMP(implicit p: Parameters) extends CoreBundle()(p) {
+  import PMP._
+
   val cfg = new PMPConfig
   val addr = UInt(width = paddrBits - lgAlign)
 
-  def enabled(prv: UInt) = cfg.p.orR && (cfg.m || prv <= PRV.S)
+  def locked = cfg.p(1)
-  def locked = cfg.p.andR
   def addrLocked(next: PMP) = locked || next.locked && next.cfg.a(1)
 
-  private def lgAlign = 2
+  private lazy val mask = Cat((0 until paddrBits - lgAlign).scanLeft(cfg.a(0))((m, i) => m && addr(i)).asUInt, UInt((BigInt(1) << lgAlign) - 1, lgAlign))
-  private def mask = (0 until paddrBits - lgAlign).scanLeft(cfg.a(0))((m, i) => m && addr(i)).asUInt
+  private lazy val comparand = addr << lgAlign
 
-  def pow2AddressMatch(x: UInt, lgSize: UInt, lgMaxSize: Int) = {
+  private def pow2Match(x: UInt, lgSize: UInt, lgMaxSize: Int) = {
-    val m = mask
+    def eval(a: UInt, b: UInt, m: UInt) = ((a ^ b) & ~m) === 0
-    def checkOne(a: UInt) = (((a >> lgAlign) ^ addr) & ~m) === 0
+    if (lgMaxSize <= lgAlign) {
-    var res = checkOne(x)
+      eval(x, comparand, mask)
-    for (i <- (1 << lgAlign) until (1 << lgMaxSize) by (1 << lgAlign))
+    } else {
-      res = res || (lgSize > log2Ceil(i) && checkOne(x | i))
+      // break up the circuit; the MSB part will be CSE'd
-    res
+      val lsbMask = mask | ~(((BigInt(1) << lgMaxSize) - 1).U << lgSize)
+      val msbMatch = eval(x >> lgMaxSize, comparand >> lgMaxSize, mask >> lgMaxSize)
+      val lsbMatch = eval(x(lgMaxSize-1, 0), comparand(lgMaxSize-1, 0), lsbMask(lgMaxSize-1, 0))
+      msbMatch && lsbMatch
+    }
   }
 
-  def hit(prv: UInt, x: UInt, lgSize: UInt, lgMaxSize: Int) = {
+  private def boundMatch(x: UInt, lsbMask: UInt, lgMaxSize: Int) = {
-    enabled(prv) && pow2AddressMatch(x, lgSize, lgMaxSize)
+    if (lgMaxSize <= lgAlign) {
+      x < comparand
+    } else {
+      // break up the circuit; the MSB part will be CSE'd
+      val msbsLess = (x >> lgMaxSize) < (comparand >> lgMaxSize)
+      val msbsEqual = ((x >> lgMaxSize) ^ (comparand >> lgMaxSize)) === 0
+      val lsbsLess = x(lgMaxSize-1, 0) < (comparand(lgMaxSize-1, 0) & lsbMask(lgMaxSize-1, 0))
+      msbsLess || (msbsEqual && lsbsLess)
     }
   }
 
+  private def lowerBoundMatch(x: UInt, lgSize: UInt, lgMaxSize: Int) =
+    !boundMatch(x, ((BigInt(1) << lgMaxSize) - 1).U << lgSize, lgMaxSize)
+
+  private def upperBoundMatch(x: UInt, lgMaxSize: Int) =
+    boundMatch(x, ((BigInt(1) << lgMaxSize) - 1).U, lgMaxSize)
+
+  private def rangeMatch(x: UInt, lgSize: UInt, lgMaxSize: Int, prev: PMP) =
+    prev.lowerBoundMatch(x, lgSize, lgMaxSize) && upperBoundMatch(x, lgMaxSize)
+
+  private def pow2Homogeneous(x: UInt, pgMask: UInt) = {
+    (mask & ~pgMask & (pgMask >> 1.U)) =/= 0 || ((x ^ comparand) & pgMask) =/= 0
+  }
+
+  private def rangeHomogeneous(x: UInt, pgMask: UInt, lgMaxSize: Int, prev: PMP) = {
+    val beginsAfterLower = !prev.boundMatch(x, ((BigInt(1) << lgMaxSize) - 1).U, lgMaxSize) // CSE with rangeMatch
+    val beginsAfterUpper = !boundMatch(x, ((BigInt(1) << lgMaxSize) - 1).U, lgMaxSize) // CSE with rangeMatch
+    val endsBeforeLower = (x & pgMask) < (prev.comparand & pgMask)
+    val endsBeforeUpper = (x & pgMask) > (comparand & pgMask)
+    endsBeforeLower || beginsAfterUpper || (beginsAfterLower && endsBeforeUpper)
+  }
+
+  def homogeneous(x: UInt, pgMask: UInt, lgMaxSize: Int, prev: PMP): Bool =
+    !cfg.p(0) || Mux(cfg.a(1), rangeHomogeneous(x, pgMask, lgMaxSize, prev), pow2Homogeneous(x, pgMask))
+
+  def aligned(x: UInt, lgSize: UInt, lgMaxSize: Int, prev: PMP): Bool = {
+    val alignMask = ~(((BigInt(1) << lgMaxSize) - 1).U << lgSize)(lgMaxSize-1, 0)
+    val rangeAligned = (prev.comparand(lgMaxSize-1, 0) & alignMask) === 0 && (comparand(lgMaxSize-1, 0) & alignMask) === 0
+    val pow2Aligned = (alignMask & ~mask(lgMaxSize-1, 0)) === 0
+    Mux(cfg.a(1), rangeAligned, pow2Aligned)
+  }
+
+  def hit(x: UInt, lgSize: UInt, lgMaxSize: Int, prev: PMP): Bool =
+    cfg.p(0) && Mux(cfg.a(1), rangeMatch(x, lgSize, lgMaxSize, prev), pow2Match(x, lgSize, lgMaxSize))
+}
+
 class PMPChecker(lgMaxSize: Int)(implicit p: Parameters) extends CoreModule()(p)
     with HasRocketCoreParameters {
   val io = new Bundle {
@@ -52,15 +103,39 @@ class PMPChecker(lgMaxSize: Int)(implicit p: Parameters) extends CoreModule()(p)
     val r = Bool(OUTPUT)
     val w = Bool(OUTPUT)
     val x = Bool(OUTPUT)
+    val pgLevel = UInt(INPUT, log2Ceil(pgLevels))
+    val homogeneous = Bool(OUTPUT)
   }
 
-  def hits = io.pmp.map(_.hit(io.prv, io.addr, io.size, lgMaxSize))
   val default = io.prv > PRV.S
-  val (r, w, x, _) = ((default, default, default, 0.U) /: (io.pmp zip hits).reverse) { case ((r, w, x, pri), (pmp, hit)) =>
+  val pmp0 = Wire(init = 0.U.asTypeOf(new PMP))
-    MuxT(hit && pmp.cfg.p >= pri, (pmp.cfg.r, pmp.cfg.w, pmp.cfg.x, pmp.cfg.p), (r, w, x, pri))
+  pmp0.cfg.r := default
+  pmp0.cfg.w := default
+  pmp0.cfg.x := default
+
+  val pgMask = (0 until pgLevels).map { i =>
+    val idxBits = pgIdxBits + (pgLevels - 1 - i) * pgLevelBits
+    require(idxBits < paddrBits)
+    val mask = (BigInt(1) << paddrBits) - (BigInt(1) << idxBits)
+    Mux(io.pgLevel >= i, mask.U, 0.U)
+  }.reduce(_|_)
+
+  io.homogeneous := ((true.B, pmp0) /: io.pmp) { case ((h, prev), pmp) =>
+    (h && pmp.homogeneous(io.addr, pgMask, lgMaxSize, prev), pmp)
+  }._1
+
+  val res = (pmp0 /: (io.pmp zip (pmp0 +: io.pmp)).reverse) { case (prev, (pmp, prevPMP)) =>
+    val hit = pmp.hit(io.addr, io.size, lgMaxSize, prevPMP)
+    val ignore = default && !pmp.cfg.m
+    val aligned = pmp.aligned(io.addr, io.size, lgMaxSize, prevPMP)
+    val cur = Wire(init = pmp)
+    cur.cfg.r := (aligned && pmp.cfg.r) || ignore
+    cur.cfg.w := (aligned && pmp.cfg.w) || ignore
+    cur.cfg.x := (aligned && pmp.cfg.x) || ignore
+    Mux(hit, cur, prev)
   }
 
-  io.r := r
+  io.r := res.cfg.r
-  io.w := w
+  io.w := res.cfg.w
-  io.x := x
+  io.x := res.cfg.x
 }

src/main/scala/rocket/TLB.scala

@@ -73,14 +73,14 @@ class TLB(lgMaxSize: Int, entries: Int)(implicit edge: TLEdgeOut, p: Parameters)
   val refill_ppn = io.ptw.resp.bits.pte.ppn(ppnBits-1, 0)
   val do_refill = Bool(usingVM) && io.ptw.resp.valid
   val invalidate_refill = state.isOneOf(s_request /* don't care */, s_wait_invalidate)
-  val mpu_ppn = Mux(do_refill, refill_ppn,
+  val mpu_physaddr = Mux(do_refill, refill_ppn << pgIdxBits,
-                Mux(vm_enabled, ppns.last, vpn(ppnBits-1, 0)))
+                     Cat(Mux(vm_enabled, ppns.last, vpn(ppnBits-1, 0)), io.req.bits.vaddr(pgIdxBits-1, 0)))
-  val mpu_physaddr = Cat(mpu_ppn, io.req.bits.vaddr(pgIdxBits-1, 0))
   val pmp = Module(new PMPChecker(lgMaxSize))
   pmp.io.addr := mpu_physaddr
   pmp.io.size := io.req.bits.size
   pmp.io.pmp := io.ptw.pmp
-  pmp.io.prv := Mux(io.req.bits.passthrough /* PTW */, PRV.S, priv)
+  pmp.io.prv := Mux(do_refill || io.req.bits.passthrough /* PTW */, PRV.S, priv)
+  pmp.io.pgLevel := io.ptw.resp.bits.level
   val legal_address = edge.manager.findSafe(mpu_physaddr).reduce(_||_)
   def fastCheck(member: TLManagerParameters => Boolean) =
     legal_address && Mux1H(edge.manager.findFast(mpu_physaddr), edge.manager.managers.map(m => Bool(member(m))))
@@ -88,10 +88,12 @@ class TLB(lgMaxSize: Int, entries: Int)(implicit edge: TLEdgeOut, p: Parameters)
   val prot_w = fastCheck(_.supportsPutFull) && pmp.io.w
   val prot_x = fastCheck(_.executable) && pmp.io.x
   val cacheable = fastCheck(_.supportsAcquireB)
-  val isSpecial = {
+  val isSpecial = !pmp.io.homogeneous || {
     val homogeneous = Wire(init = false.B)
     for (i <- 0 until pgLevels) {
-      when (io.ptw.resp.bits.level === i) { homogeneous := TLBPageLookup(edge.manager.managers, xLen, p(CacheBlockBytes), BigInt(1) << (pgIdxBits + ((pgLevels - 1 - i) * pgLevelBits)))(mpu_physaddr).homogeneous }
+      when (io.ptw.resp.bits.level >= i) {
+        homogeneous := TLBPageLookup(edge.manager.managers, xLen, p(CacheBlockBytes), BigInt(1) << (pgIdxBits + ((pgLevels - 1 - i) * pgLevelBits)))(mpu_physaddr).homogeneous
+      }
     }
     !homogeneous
   }
@@ -142,7 +144,7 @@ class TLB(lgMaxSize: Int, entries: Int)(implicit edge: TLEdgeOut, p: Parameters)
   }
 
   val plru = new PseudoLRU(normalEntries)
-  val repl_waddr = Mux(!valid.andR, PriorityEncoder(~valid), plru.replace)
+  val repl_waddr = Mux(!valid(normalEntries-1, 0).andR, PriorityEncoder(~valid(normalEntries-1, 0)), plru.replace)
 
   val priv_ok = Mux(priv_s, ~Mux(io.ptw.status.sum, UInt(0), u_array), u_array)
   val w_array = Cat(prot_w, priv_ok & ~(~prot_w << specialEntry) & sw_array)