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More WIP on PMP

This commit is contained in:
Andrew Waterman 2017-03-20 01:34:47 -07:00
parent 2888779422
commit 86d84959cf
2 changed files with 105 additions and 28 deletions
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113
src/main/scala/rocket/PMP.scala
View File

@ -17,29 +17,80 @@ 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.andR
def locked = cfg.p(1)
def addrLocked(next: PMP) = locked || next.locked && next.cfg.a(1)
private def lgAlign = 2
private def mask = (0 until paddrBits - lgAlign).scanLeft(cfg.a(0))((m, i) => m && addr(i)).asUInt
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 lazy val comparand = addr << lgAlign
def pow2AddressMatch(x: UInt, lgSize: UInt, lgMaxSize: Int) = {
val m = mask
def checkOne(a: UInt) = (((a >> lgAlign) ^ addr) & ~m) === 0
var res = checkOne(x)
for (i <- (1 << lgAlign) until (1 << lgMaxSize) by (1 << lgAlign))
res = res || (lgSize > log2Ceil(i) && checkOne(x | i))
res
private def pow2Match(x: UInt, lgSize: UInt, lgMaxSize: Int) = {
def eval(a: UInt, b: UInt, m: UInt) = ((a ^ b) & ~m) === 0
if (lgMaxSize <= lgAlign) {
eval(x, comparand, mask)
} else {
// break up the circuit; the MSB part will be CSE'd
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) = {
enabled(prv) && pow2AddressMatch(x, lgSize, lgMaxSize)
private def boundMatch(x: UInt, lsbMask: UInt, lgMaxSize: Int) = {
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)
@ -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)) =>
MuxT(hit && pmp.cfg.p >= pri, (pmp.cfg.r, pmp.cfg.w, pmp.cfg.x, pmp.cfg.p), (r, w, x, pri))
val pmp0 = Wire(init = 0.U.asTypeOf(new PMP))
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.w := w
io.x := x
io.r := res.cfg.r
io.w := res.cfg.w
io.x := res.cfg.x
}

20
src/main/scala/rocket/TLB.scala
View File

@ -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,
Mux(vm_enabled, ppns.last, vpn(ppnBits-1, 0)))
val mpu_physaddr = Cat(mpu_ppn, io.req.bits.vaddr(pgIdxBits-1, 0))
val mpu_physaddr = Mux(do_refill, refill_ppn << pgIdxBits,
Cat(Mux(vm_enabled, ppns.last, vpn(ppnBits-1, 0)), 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
}
@ -114,7 +116,7 @@ class TLB(lgMaxSize: Int, entries: Int)(implicit edge: TLEdgeOut, p: Parameters)
ppn = Cat(ppn, (Mux(level < i, vpn, 0.U) | partialPPN)(vpnBits - i*pgLevelBits - 1, vpnBits - (i + 1)*pgLevelBits))
ppn
}
// permission bit arrays
val u_array = Reg(UInt(width = totalEntries)) // user permission
val g_array = Reg(UInt(width = totalEntries)) // global mapping
@ -140,9 +142,9 @@ class TLB(lgMaxSize: Int, entries: Int)(implicit edge: TLEdgeOut, p: Parameters)
xr_array := Mux(pte.sx() && (isSpecial || prot_r), xr_array | mask, xr_array & ~mask)
cash_array := Mux(cacheable, cash_array | mask, cash_array & ~mask)
}
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)