riscv/rocket-chip
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Implement priv-1.9 PTE scheme

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This commit is contained in:
Andrew Waterman 2016-07-05 19:19:49 -07:00
parent ebefe57036
commit 8bd7e3932b
3 changed files with 42 additions and 33 deletions
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4
rocket/src/main/scala/csr.scala
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@ -17,7 +17,8 @@ class MStatus extends Bundle {
val sd_rv32 = Bool()
val zero2 = UInt(width = 2)
val vm = UInt(width = 5)
val zero1 = UInt(width = 5)
val zero1 = UInt(width = 4)
val mxr = Bool()
val pum = Bool()
val mprv = Bool()
val xs = UInt(width = 2)
@ -463,6 +464,7 @@ class CSRFile(implicit p: Parameters) extends CoreModule()(p)
reg_mstatus.mprv := new_mstatus.mprv
when (supportedModes contains new_mstatus.mpp) { reg_mstatus.mpp := new_mstatus.mpp }
if (supportedModes.size > 2) {
reg_mstatus.mxr := new_mstatus.mxr
reg_mstatus.pum := new_mstatus.pum
reg_mstatus.spp := new_mstatus.spp
reg_mstatus.spie := new_mstatus.spie

46
rocket/src/main/scala/ptw.scala
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@ -9,8 +9,10 @@ import Util._
import cde.{Parameters, Field}
class PTWReq(implicit p: Parameters) extends CoreBundle()(p) {
val addr = UInt(width = vpnBits)
val prv = Bits(width = 2)
val pum = Bool()
val mxr = Bool()
val addr = UInt(width = vpnBits)
val store = Bool()
val fetch = Bool()
}
@ -34,23 +36,32 @@ class DatapathPTWIO(implicit p: Parameters) extends CoreBundle()(p) {
}
class PTE(implicit p: Parameters) extends CoreBundle()(p) {
val ppn = Bits(width = ppnBits)
val reserved_for_software = Bits(width = 3)
val reserved_for_hardware = Bits(width = 16)
val ppn = UInt(width = 38)
val reserved_for_software = Bits(width = 2)
val d = Bool()
val a = Bool()
val g = Bool()
val u = Bool()
val x = Bool()
val w = Bool()
val r = Bool()
val typ = Bits(width = 4)
val v = Bool()
def table(dummy: Int = 0) = v && typ < 2
def leaf(dummy: Int = 0) = v && typ >= 2
def ur(dummy: Int = 0) = leaf() && typ < 8
def uw(dummy: Int = 0) = ur() && typ(0)
def ux(dummy: Int = 0) = ur() && typ(1)
def sr(dummy: Int = 0) = leaf()
def sw(dummy: Int = 0) = leaf() && typ(0)
def sx(dummy: Int = 0) = v && typ >= 4 && typ(1)
def access_ok(prv: Bits, store: Bool, fetch: Bool) =
Mux(prv(0), Mux(fetch, sx(), Mux(store, sw(), sr())), Mux(fetch, ux(), Mux(store, uw(), ur())))
def table(dummy: Int = 0) = v && !r && !w && !x
def leaf(dummy: Int = 0) = v && (r || (x && !w))
def ur(dummy: Int = 0) = sr() && u
def uw(dummy: Int = 0) = sw() && u
def ux(dummy: Int = 0) = sx() && u
def sr(dummy: Int = 0) = leaf() && r
def sw(dummy: Int = 0) = leaf() && w
def sx(dummy: Int = 0) = leaf() && x
def access_ok(req: PTWReq) = {
val perm_ok = Mux(req.fetch, x, Mux(req.store, w, r || (x && req.mxr)))
val priv_ok = Mux(u, !req.pum, req.prv(0))
leaf() && priv_ok && perm_ok
}
}
class PTW(n: Int)(implicit p: Parameters) extends CoreModule()(p) {
@ -106,14 +117,13 @@ class PTW(n: Int)(implicit p: Parameters) extends CoreModule()(p) {
(hit, Mux1H(hits, data))
}
val perm_ok = pte.access_ok(r_req.prv, r_req.store, r_req.fetch)
val set_dirty_bit = perm_ok && (!pte.r || (r_req.store && !pte.d))
val set_dirty_bit = pte.access_ok(r_req) && (!pte.a || (r_req.store && !pte.d))
when (io.mem.resp.valid && state === s_wait && !set_dirty_bit) {
r_pte := pte
}
val pte_wdata = Wire(init=new PTE().fromBits(0))
pte_wdata.r := true
pte_wdata.a := true
pte_wdata.d := r_req.store
io.mem.req.valid := state === s_req || state === s_set_dirty
@ -162,7 +172,7 @@ class PTW(n: Int)(implicit p: Parameters) extends CoreModule()(p) {
}
when (io.mem.resp.valid) {
state := s_done
when (pte.leaf() && set_dirty_bit) {
when (set_dirty_bit) {
state := s_set_dirty
}
when (pte.table() && count < pgLevels-1) {

25
rocket/src/main/scala/tlb.scala
View File

@ -56,12 +56,11 @@ class TLB(implicit val p: Parameters) extends Module with HasTLBParameters {
val hits = hitsVec.toBits
// permission bit arrays
val ur_array = Reg(UInt(width = entries)) // user read permission
val uw_array = Reg(UInt(width = entries)) // user write permission
val ux_array = Reg(UInt(width = entries)) // user execute permission
val sr_array = Reg(UInt(width = entries)) // supervisor read permission
val sw_array = Reg(UInt(width = entries)) // supervisor write permission
val sx_array = Reg(UInt(width = entries)) // supervisor execute permission
val pte_array = Reg(new PTE)
val u_array = Reg(UInt(width = entries)) // user permission
val sw_array = Reg(UInt(width = entries)) // write permission
val sx_array = Reg(UInt(width = entries)) // execute permission
val sr_array = Reg(UInt(width = entries)) // read permission
val dirty_array = Reg(UInt(width = entries)) // PTE dirty bit
when (io.ptw.resp.valid) {
val pte = io.ptw.resp.bits.pte
@ -70,9 +69,7 @@ class TLB(implicit val p: Parameters) extends Module with HasTLBParameters {
val mask = UIntToOH(r_refill_waddr)
valid := valid | mask
ur_array := Mux(pte.ur(), ur_array | mask, ur_array & ~mask)
uw_array := Mux(pte.uw(), uw_array | mask, uw_array & ~mask)
ux_array := Mux(pte.ux(), ux_array | mask, ux_array & ~mask)
u_array := Mux(pte.u, u_array | mask, u_array & ~mask)
sr_array := Mux(pte.sr(), sr_array | mask, sr_array & ~mask)
sw_array := Mux(pte.sw(), sw_array | mask, sw_array & ~mask)
sx_array := Mux(pte.sx(), sx_array | mask, sx_array & ~mask)
@ -88,10 +85,10 @@ class TLB(implicit val p: Parameters) extends Module with HasTLBParameters {
val priv_s = priv === PRV.S
val priv_uses_vm = priv <= PRV.S && !io.ptw.status.debug
val pum_ok = ~Mux(io.ptw.status.pum, ur_array, UInt(0))
val r_array = Mux(priv_s, sr_array & pum_ok, ur_array)
val w_array = Mux(priv_s, sw_array & pum_ok, uw_array)
val x_array = Mux(priv_s, sx_array, ux_array)
val priv_ok = Mux(priv_s, ~Mux(io.ptw.status.pum, u_array, UInt(0)), u_array)
val w_array = priv_ok & sw_array
val x_array = priv_ok & sx_array
val r_array = priv_ok & (sr_array | Mux(io.ptw.status.mxr, x_array, UInt(0)))
val vm_enabled = Bool(usingVM) && io.ptw.status.vm(3) && priv_uses_vm && !io.req.bits.passthrough
val bad_va =
@ -118,8 +115,8 @@ class TLB(implicit val p: Parameters) extends Module with HasTLBParameters {
io.resp.ppn := Mux(vm_enabled, Mux1H(hitsVec, ppns), io.req.bits.vpn(ppnBits-1,0))
io.ptw.req.valid := state === s_request
io.ptw.req.bits := io.ptw.status
io.ptw.req.bits.addr := r_refill_tag
io.ptw.req.bits.prv := io.ptw.status.prv
io.ptw.req.bits.store := r_req.store
io.ptw.req.bits.fetch := r_req.instruction