Python simulator of a N-way set-associative cache:
https://github.com/vaskevich/CacheSim/blob/master/cachesim.py
"""
-import sys
-sys.path.append("ariane/src/")
from nmigen import Array, Cat, Memory, Module, Signal, Mux, Elaboratable
from nmigen.compat.genlib import fsm
from nmigen.cli import main
from nmigen.cli import verilog, rtlil
-from AddressEncoder import AddressEncoder
-from MemorySet import MemorySet
+from .AddressEncoder import AddressEncoder
+from .MemorySet import MemorySet
# TODO: use a LFSR that advances continuously and picking the bottom
# few bits from it to select which cache line to replace, instead of PLRU
# http://bugs.libre-riscv.org/show_bug.cgi?id=71
-from plru import PLRU
-from LFSR import LFSR, LFSR_POLY_24
+from .ariane.plru import PLRU
+from .LFSR import LFSR, LFSR_POLY_24
SA_NA = "00" # no action (none)
SA_RD = "01" # read
--- /dev/null
+from nmigen import Const
+
+INSTR_ADDR_MISALIGNED = Const(0, 64)
+INSTR_ACCESS_FAULT = Const(1, 64)
+ILLEGAL_INSTR = Const(2, 64)
+BREAKPOINT = Const(3, 64)
+LD_ADDR_MISALIGNED = Const(4, 64)
+LD_ACCESS_FAULT = Const(5, 64)
+ST_ADDR_MISALIGNED = Const(6, 64)
+ST_ACCESS_FAULT = Const(7, 64)
+ENV_CALL_UMODE = Const(8, 64) # environment call from user mode
+ENV_CALL_SMODE = Const(9, 64) # environment call from supervisor mode
+ENV_CALL_MMODE = Const(11, 64) # environment call from machine mode
+INSTR_PAGE_FAULT = Const(12, 64) # Instruction page fault
+LOAD_PAGE_FAULT = Const(13, 64) # Load page fault
+STORE_PAGE_FAULT = Const(15, 64) # Store page fault
--- /dev/null
+"""
+# Copyright 2018 ETH Zurich and University of Bologna.
+# Copyright and related rights are licensed under the Solderpad Hardware
+# License, Version 0.51 (the "License"); you may not use this file except in
+# compliance with the License. You may obtain a copy of the License at
+# http:#solderpad.org/licenses/SHL-0.51. Unless required by applicable law
+# or agreed to in writing, software, hardware and materials distributed under
+# this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+# CONDITIONS OF ANY KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations under the License.
+#
+# Author: Florian Zaruba, ETH Zurich
+# Date: 19/04/2017
+# Description: Memory Management Unit for Ariane, contains TLB and
+# address translation unit. SV39 as defined in RISC-V
+# privilege specification 1.11-WIP
+
+import ariane_pkg::*;
+"""
+
+from nmigen import Const, Signal, Cat, Module, Mux
+from nmigen.cli import verilog, rtlil
+
+from ptw import DCacheReqI, DCacheReqO, TLBUpdate, PTE, PTW
+from tlb import TLB
+from exceptcause import (INSTR_ACCESS_FAULT, INSTR_PAGE_FAULT,
+ LOAD_PAGE_FAULT, STORE_PAGE_FAULT)
+
+PRIV_LVL_M = Const(0b11, 2)
+PRIV_LVL_S = Const(0b01, 2)
+PRIV_LVL_U = Const(0b00, 2)
+
+
+class RVException:
+ def __init__(self):
+ self.cause = Signal(64) # cause of exception
+ self.tval = Signal(64) # more info of causing exception
+ # (e.g.: instruction causing it),
+ # address of LD/ST fault
+ self.valid = Signal()
+
+ def eq(self, inp):
+ res = []
+ for (o, i) in zip(self.ports(), inp.ports()):
+ res.append(o.eq(i))
+ return res
+
+ def __iter__(self):
+ yield self.cause
+ yield self.tval
+ yield self.valid
+
+ def ports(self):
+ return list(self)
+
+
+class ICacheReqI:
+ def __init__(self):
+ self.fetch_valid = Signal() # address translation valid
+ self.fetch_paddr = Signal(64) # physical address in
+ self.fetch_exception = RVException() # exception occurred during fetch
+
+ def __iter__(self):
+ yield self.fetch_valid
+ yield self.fetch_paddr
+ yield from self.fetch_exception
+
+ def ports(self):
+ return list(self)
+
+
+class ICacheReqO:
+ def __init__(self):
+ self.fetch_req = Signal() # address translation request
+ self.fetch_vaddr = Signal(64) # virtual address out
+
+ def __iter__(self):
+ yield self.fetch_req
+ yield self.fetch_vaddr
+
+ def ports(self):
+ return list(self)
+
+
+class MMU:
+ def __init__(self, instr_tlb_entries = 4,
+ data_tlb_entries = 4,
+ asid_width = 1):
+ self.instr_tlb_entries = instr_tlb_entries
+ self.data_tlb_entries = data_tlb_entries
+ self.asid_width = asid_width
+
+ self.flush_i = Signal()
+ self.enable_translation_i = Signal()
+ self.en_ld_st_translation_i = Signal() # enable VM translation for LD/ST
+ # IF interface
+ self.icache_areq_i = ICacheReqO()
+ self.icache_areq_o = ICacheReqI()
+ # LSU interface
+ # this is a more minimalistic interface because the actual addressing
+ # logic is handled in the LSU as we distinguish load and stores,
+ # what we do here is simple address translation
+ self.misaligned_ex_i = RVException()
+ self.lsu_req_i = Signal() # request address translation
+ self.lsu_vaddr_i = Signal(64) # virtual address in
+ self.lsu_is_store_i = Signal() # the translation is requested by a store
+ # if we need to walk the page table we can't grant in the same cycle
+
+ # Cycle 0
+ self.lsu_dtlb_hit_o = Signal() # sent in the same cycle as the request
+ # if translation hits in the DTLB
+ # Cycle 1
+ self.lsu_valid_o = Signal() # translation is valid
+ self.lsu_paddr_o = Signal(64) # translated address
+ self.lsu_exception_o = RVException() # addr translate threw exception
+
+ # General control signals
+ self.priv_lvl_i = Signal(2)
+ self.ld_st_priv_lvl_i = Signal(2)
+ self.sum_i = Signal()
+ self.mxr_i = Signal()
+ # input logic flag_mprv_i,
+ self.satp_ppn_i = Signal(44)
+ self.asid_i = Signal(self.asid_width)
+ self.flush_tlb_i = Signal()
+ # Performance counters
+ self.itlb_miss_o = Signal()
+ self.dtlb_miss_o = Signal()
+ # PTW memory interface
+ self.req_port_i = DCacheReqO()
+ self.req_port_o = DCacheReqI()
+
+ def elaborate(self, platform):
+ m = Module()
+
+ iaccess_err = Signal() # insufficient priv to access instr page
+ daccess_err = Signal() # insufficient priv to access data page
+ ptw_active = Signal() # PTW is currently walking a page table
+ walking_instr = Signal() # PTW is walking because of an ITLB miss
+ ptw_error = Signal() # PTW threw an exception
+
+ update_vaddr = Signal(39)
+ uaddr64 = Cat(update_vaddr, Const(0, 25)) # extend to 64bit with zeros
+ update_ptw_itlb = TLBUpdate(self.asid_width)
+ update_ptw_dtlb = TLBUpdate(self.asid_width)
+
+ itlb_lu_access = Signal()
+ itlb_content = PTE()
+ itlb_is_2M = Signal()
+ itlb_is_1G = Signal()
+ itlb_lu_hit = Signal()
+
+ dtlb_lu_access = Signal()
+ dtlb_content = PTE()
+ dtlb_is_2M = Signal()
+ dtlb_is_1G = Signal()
+ dtlb_lu_hit = Signal()
+
+ # Assignments
+ m.d.comb += [itlb_lu_access.eq(self.icache_areq_i.fetch_req),
+ dtlb_lu_access.eq(self.lsu_req_i)
+ ]
+
+ # ITLB
+ m.submodules.i_tlb = i_tlb = TLB(self.instr_tlb_entries,
+ self.asid_width)
+ m.d.comb += [i_tlb.flush_i.eq(self.flush_tlb_i),
+ i_tlb.update_i.eq(update_ptw_itlb),
+ i_tlb.lu_access_i.eq(itlb_lu_access),
+ i_tlb.lu_asid_i.eq(self.asid_i),
+ i_tlb.lu_vaddr_i.eq(self.icache_areq_i.fetch_vaddr),
+ itlb_content.eq(i_tlb.lu_content_o),
+ itlb_is_2M.eq(i_tlb.lu_is_2M_o),
+ itlb_is_1G.eq(i_tlb.lu_is_1G_o),
+ itlb_lu_hit.eq(i_tlb.lu_hit_o),
+ ]
+
+ # DTLB
+ m.submodules.d_tlb = d_tlb = TLB(self.data_tlb_entries,
+ self.asid_width)
+ m.d.comb += [d_tlb.flush_i.eq(self.flush_tlb_i),
+ d_tlb.update_i.eq(update_ptw_dtlb),
+ d_tlb.lu_access_i.eq(dtlb_lu_access),
+ d_tlb.lu_asid_i.eq(self.asid_i),
+ d_tlb.lu_vaddr_i.eq(self.lsu_vaddr_i),
+ dtlb_content.eq(d_tlb.lu_content_o),
+ dtlb_is_2M.eq(d_tlb.lu_is_2M_o),
+ dtlb_is_1G.eq(d_tlb.lu_is_1G_o),
+ dtlb_lu_hit.eq(d_tlb.lu_hit_o),
+ ]
+
+ # PTW
+ m.submodules.ptw = ptw = PTW(self.asid_width)
+ m.d.comb += [ptw_active.eq(ptw.ptw_active_o),
+ walking_instr.eq(ptw.walking_instr_o),
+ ptw_error.eq(ptw.ptw_error_o),
+ ptw.enable_translation_i.eq(self.enable_translation_i),
+
+ update_vaddr.eq(ptw.update_vaddr_o),
+ update_ptw_itlb.eq(ptw.itlb_update_o),
+ update_ptw_dtlb.eq(ptw.dtlb_update_o),
+
+ ptw.itlb_access_i.eq(itlb_lu_access),
+ ptw.itlb_hit_i.eq(itlb_lu_hit),
+ ptw.itlb_vaddr_i.eq(self.icache_areq_i.fetch_vaddr),
+
+ ptw.dtlb_access_i.eq(dtlb_lu_access),
+ ptw.dtlb_hit_i.eq(dtlb_lu_hit),
+ ptw.dtlb_vaddr_i.eq(self.lsu_vaddr_i),
+
+ ptw.req_port_i.eq(self.req_port_i),
+ self.req_port_o.eq(ptw.req_port_o),
+ ]
+
+ # ila_1 i_ila_1 (
+ # .clk(clk_i), # input wire clk
+ # .probe0({req_port_o.address_tag, req_port_o.address_index}),
+ # .probe1(req_port_o.data_req), # input wire [63:0] probe1
+ # .probe2(req_port_i.data_gnt), # input wire [0:0] probe2
+ # .probe3(req_port_i.data_rdata), # input wire [0:0] probe3
+ # .probe4(req_port_i.data_rvalid), # input wire [0:0] probe4
+ # .probe5(ptw_error), # input wire [1:0] probe5
+ # .probe6(update_vaddr), # input wire [0:0] probe6
+ # .probe7(update_ptw_itlb.valid), # input wire [0:0] probe7
+ # .probe8(update_ptw_dtlb.valid), # input wire [0:0] probe8
+ # .probe9(dtlb_lu_access), # input wire [0:0] probe9
+ # .probe10(lsu_vaddr_i), # input wire [0:0] probe10
+ # .probe11(dtlb_lu_hit), # input wire [0:0] probe11
+ # .probe12(itlb_lu_access), # input wire [0:0] probe12
+ # .probe13(icache_areq_i.fetch_vaddr), # input wire [0:0] probe13
+ # .probe14(itlb_lu_hit) # input wire [0:0] probe13
+ # );
+
+ #-----------------------
+ # Instruction Interface
+ #-----------------------
+ # The instruction interface is a simple request response interface
+
+ # MMU disabled: just pass through
+ m.d.comb += [self.icache_areq_o.fetch_valid.eq(
+ self.icache_areq_i.fetch_req),
+ # play through in case we disabled address translation
+ self.icache_areq_o.fetch_paddr.eq(
+ self.icache_areq_i.fetch_vaddr)
+ ]
+ # two potential exception sources:
+ # 1. HPTW threw an exception -> signal with a page fault exception
+ # 2. We got an access error because of insufficient permissions ->
+ # throw an access exception
+ m.d.comb += self.icache_areq_o.fetch_exception.valid.eq(0)
+ # Check whether we are allowed to access this memory region
+ # from a fetch perspective
+
+ # XXX TODO: use PermissionValidator instead [we like modules]
+ m.d.comb += iaccess_err.eq(self.icache_areq_i.fetch_req & \
+ (((self.priv_lvl_i == PRIV_LVL_U) & \
+ ~itlb_content.u) | \
+ ((self.priv_lvl_i == PRIV_LVL_S) & \
+ itlb_content.u)))
+
+ # MMU enabled: address from TLB, request delayed until hit.
+ # Error when TLB hit and no access right or TLB hit and
+ # translated address not valid (e.g. AXI decode error),
+ # or when PTW performs walk due to ITLB miss and raises
+ # an error.
+ with m.If (self.enable_translation_i):
+ # we work with SV39, so if VM is enabled, check that
+ # all bits [63:38] are equal
+ with m.If (self.icache_areq_i.fetch_req & \
+ ~(((~self.icache_areq_i.fetch_vaddr[38:64]) == 0) | \
+ (self.icache_areq_i.fetch_vaddr[38:64]) == 0)):
+ fe = self.icache_areq_o.fetch_exception
+ m.d.comb += [fe.cause.eq(INSTR_ACCESS_FAULT),
+ fe.tval.eq(self.icache_areq_i.fetch_vaddr),
+ fe.valid.eq(1)
+ ]
+
+ m.d.comb += self.icache_areq_o.fetch_valid.eq(0)
+
+ # 4K page
+ paddr = Signal.like(self.icache_areq_o.fetch_paddr)
+ paddr4k = Cat(self.icache_areq_i.fetch_vaddr[0:12],
+ itlb_content.ppn)
+ m.d.comb += paddr.eq(paddr4k)
+ # Mega page
+ with m.If(itlb_is_2M):
+ m.d.comb += paddr[12:21].eq(
+ self.icache_areq_i.fetch_vaddr[12:21])
+ # Giga page
+ with m.If(itlb_is_1G):
+ m.d.comb += paddr[12:30].eq(
+ self.icache_areq_i.fetch_vaddr[12:30])
+ m.d.comb += self.icache_areq_o.fetch_paddr.eq(paddr)
+
+ # ---------
+ # ITLB Hit
+ # --------
+ # if we hit the ITLB output the request signal immediately
+ with m.If(itlb_lu_hit):
+ m.d.comb += self.icache_areq_o.fetch_valid.eq(
+ self.icache_areq_i.fetch_req)
+ # we got an access error
+ with m.If (iaccess_err):
+ # throw a page fault
+ fe = self.icache_areq_o.fetch_exception
+ m.d.comb += [fe.cause.eq(INSTR_ACCESS_FAULT),
+ fe.tval.eq(self.icache_areq_i.fetch_vaddr),
+ fe.valid.eq(1)
+ ]
+ # ---------
+ # ITLB Miss
+ # ---------
+ # watch out for exceptions happening during walking the page table
+ with m.Elif(ptw_active & walking_instr):
+ m.d.comb += self.icache_areq_o.fetch_valid.eq(ptw_error)
+ fe = self.icache_areq_o.fetch_exception
+ m.d.comb += [fe.cause.eq(INSTR_PAGE_FAULT),
+ fe.tval.eq(uaddr64),
+ fe.valid.eq(1)
+ ]
+
+ #-----------------------
+ # Data Interface
+ #-----------------------
+
+ lsu_vaddr = Signal(64)
+ dtlb_pte = PTE()
+ misaligned_ex = RVException()
+ lsu_req = Signal()
+ lsu_is_store = Signal()
+ dtlb_hit = Signal()
+ dtlb_is_2M = Signal()
+ dtlb_is_1G = Signal()
+
+ # check if we need to do translation or if we are always
+ # ready (e.g.: we are not translating anything)
+ m.d.comb += self.lsu_dtlb_hit_o.eq(Mux(self.en_ld_st_translation_i,
+ dtlb_lu_hit, 1))
+
+ # The data interface is simpler and only consists of a
+ # request/response interface
+ m.d.comb += [
+ # save request and DTLB response
+ lsu_vaddr.eq(self.lsu_vaddr_i),
+ lsu_req.eq(self.lsu_req_i),
+ misaligned_ex.eq(self.misaligned_ex_i),
+ dtlb_pte.eq(dtlb_content),
+ dtlb_hit.eq(dtlb_lu_hit),
+ lsu_is_store.eq(self.lsu_is_store_i),
+ dtlb_is_2M.eq(dtlb_is_2M),
+ dtlb_is_1G.eq(dtlb_is_1G),
+ ]
+ m.d.sync += [
+ self.lsu_paddr_o.eq(lsu_vaddr),
+ self.lsu_valid_o.eq(lsu_req),
+ self.lsu_exception_o.eq(misaligned_ex),
+ ]
+
+ sverr = Signal()
+ usrerr = Signal()
+
+ m.d.comb += [
+ # mute misaligned exceptions if there is no request
+ # otherwise they will throw accidental exceptions
+ misaligned_ex.valid.eq(self.misaligned_ex_i.valid & self.lsu_req_i),
+
+ # SUM is not set and we are trying to access a user
+ # page in supervisor mode
+ sverr.eq(self.ld_st_priv_lvl_i == PRIV_LVL_S & ~self.sum_i & \
+ dtlb_pte.u),
+ # this is not a user page but we are in user mode and
+ # trying to access it
+ usrerr.eq(self.ld_st_priv_lvl_i == PRIV_LVL_U & ~dtlb_pte.u),
+
+ # Check if the User flag is set, then we may only
+ # access it in supervisor mode if SUM is enabled
+ daccess_err.eq(sverr | usrerr),
+ ]
+
+ # translation is enabled and no misaligned exception occurred
+ with m.If(self.en_ld_st_translation_i & ~misaligned_ex.valid):
+ m.d.comb += lsu_req.eq(0)
+ # 4K page
+ paddr = Signal.like(lsu_vaddr)
+ paddr4k = Cat(lsu_vaddr[0:12], itlb_content.ppn)
+ m.d.comb += paddr.eq(paddr4k)
+ # Mega page
+ with m.If(dtlb_is_2M):
+ m.d.comb += paddr[12:21].eq(lsu_vaddr[12:21])
+ # Giga page
+ with m.If(dtlb_is_1G):
+ m.d.comb += paddr[12:30].eq(lsu_vaddr[12:30])
+ m.d.sync += self.lsu_paddr_o.eq(paddr)
+
+ # ---------
+ # DTLB Hit
+ # --------
+ with m.If(dtlb_hit & lsu_req):
+ m.d.comb += lsu_req.eq(1)
+ # this is a store
+ with m.If (lsu_is_store):
+ # check if the page is write-able and
+ # we are not violating privileges
+ # also check if the dirty flag is set
+ with m.If(~dtlb_pte.w | daccess_err | ~dtlb_pte.d):
+ le = self.lsu_exception_o
+ m.d.sync += [le.cause.eq(STORE_PAGE_FAULT),
+ le.tval.eq(lsu_vaddr),
+ le.valid.eq(1)
+ ]
+
+ # this is a load, check for sufficient access
+ # privileges - throw a page fault if necessary
+ with m.Elif(daccess_err):
+ le = self.lsu_exception_o
+ m.d.sync += [le.cause.eq(LOAD_PAGE_FAULT),
+ le.tval.eq(lsu_vaddr),
+ le.valid.eq(1)
+ ]
+ # ---------
+ # DTLB Miss
+ # ---------
+ # watch out for exceptions
+ with m.Elif (ptw_active & ~walking_instr):
+ # page table walker threw an exception
+ with m.If (ptw_error):
+ # an error makes the translation valid
+ m.d.comb += lsu_req.eq(1)
+ # the page table walker can only throw page faults
+ with m.If (lsu_is_store):
+ le = self.lsu_exception_o
+ m.d.sync += [le.cause.eq(STORE_PAGE_FAULT),
+ le.tval.eq(uaddr64),
+ le.valid.eq(1)
+ ]
+ with m.Else():
+ m.d.sync += [le.cause.eq(LOAD_PAGE_FAULT),
+ le.tval.eq(uaddr64),
+ le.valid.eq(1)
+ ]
+
+ return m
+
+ def ports(self):
+ return [self.flush_i, self.enable_translation_i,
+ self.en_ld_st_translation_i,
+ self.lsu_req_i,
+ self.lsu_vaddr_i, self.lsu_is_store_i, self.lsu_dtlb_hit_o,
+ self.lsu_valid_o, self.lsu_paddr_o,
+ self.priv_lvl_i, self.ld_st_priv_lvl_i, self.sum_i, self.mxr_i,
+ self.satp_ppn_i, self.asid_i, self.flush_tlb_i,
+ self.itlb_miss_o, self.dtlb_miss_o] + \
+ self.icache_areq_i.ports() + self.icache_areq_o.ports() + \
+ self.req_port_i.ports() + self.req_port_o.ports() + \
+ self.misaligned_ex_i.ports() + self.lsu_exception_o.ports()
+
+if __name__ == '__main__':
+ mmu = MMU()
+ vl = rtlil.convert(mmu, ports=mmu.ports())
+ with open("test_mmu.il", "w") as f:
+ f.write(vl)
+
--- /dev/null
+from nmigen import Signal, Module, Cat, Const
+from nmigen.hdl.ir import Elaboratable
+from math import log2
+
+from .ptw import TLBUpdate, PTE, ASID_WIDTH
+
+class PLRU(Elaboratable):
+ """ PLRU - Pseudo Least Recently Used Replacement
+
+ PLRU-tree indexing:
+ lvl0 0
+ / \
+ / \
+ lvl1 1 2
+ / \ / \
+ lvl2 3 4 5 6
+ / \ /\/\ /\
+ ... ... ... ...
+ """
+ def __init__(self, entries):
+ self.entries = entries
+ self.lu_hit = Signal(entries)
+ self.replace_en_o = Signal(entries)
+ self.lu_access_i = Signal()
+ # Tree (bit per entry)
+ self.TLBSZ = 2*(self.entries-1)
+ self.plru_tree = Signal(self.TLBSZ)
+ self.plru_tree_o = Signal(self.TLBSZ)
+
+ def elaborate(self, platform=None):
+ m = Module()
+
+ # Just predefine which nodes will be set/cleared
+ # E.g. for a TLB with 8 entries, the for-loop is semantically
+ # equivalent to the following pseudo-code:
+ # unique case (1'b1)
+ # lu_hit[7]: plru_tree[0, 2, 6] = {1, 1, 1};
+ # lu_hit[6]: plru_tree[0, 2, 6] = {1, 1, 0};
+ # lu_hit[5]: plru_tree[0, 2, 5] = {1, 0, 1};
+ # lu_hit[4]: plru_tree[0, 2, 5] = {1, 0, 0};
+ # lu_hit[3]: plru_tree[0, 1, 4] = {0, 1, 1};
+ # lu_hit[2]: plru_tree[0, 1, 4] = {0, 1, 0};
+ # lu_hit[1]: plru_tree[0, 1, 3] = {0, 0, 1};
+ # lu_hit[0]: plru_tree[0, 1, 3] = {0, 0, 0};
+ # default: begin /* No hit */ end
+ # endcase
+ LOG_TLB = int(log2(self.entries))
+ print(LOG_TLB)
+ for i in range(self.entries):
+ # we got a hit so update the pointer as it was least recently used
+ hit = Signal(reset_less=True)
+ m.d.comb += hit.eq(self.lu_hit[i] & self.lu_access_i)
+ with m.If(hit):
+ # Set the nodes to the values we would expect
+ for lvl in range(LOG_TLB):
+ idx_base = (1<<lvl)-1
+ # lvl0 <=> MSB, lvl1 <=> MSB-1, ...
+ shift = LOG_TLB - lvl;
+ new_idx = Const(~((i >> (shift-1)) & 1), (1, False))
+ plru_idx = idx_base + (i >> shift)
+ print ("plru", i, lvl, hex(idx_base),
+ plru_idx, shift, new_idx)
+ m.d.comb += self.plru_tree_o[plru_idx].eq(new_idx)
+
+ # Decode tree to write enable signals
+ # Next for-loop basically creates the following logic for e.g.
+ # an 8 entry TLB (note: pseudo-code obviously):
+ # replace_en[7] = &plru_tree[ 6, 2, 0]; #plru_tree[0,2,6]=={1,1,1}
+ # replace_en[6] = &plru_tree[~6, 2, 0]; #plru_tree[0,2,6]=={1,1,0}
+ # replace_en[5] = &plru_tree[ 5,~2, 0]; #plru_tree[0,2,5]=={1,0,1}
+ # replace_en[4] = &plru_tree[~5,~2, 0]; #plru_tree[0,2,5]=={1,0,0}
+ # replace_en[3] = &plru_tree[ 4, 1,~0]; #plru_tree[0,1,4]=={0,1,1}
+ # replace_en[2] = &plru_tree[~4, 1,~0]; #plru_tree[0,1,4]=={0,1,0}
+ # replace_en[1] = &plru_tree[ 3,~1,~0]; #plru_tree[0,1,3]=={0,0,1}
+ # replace_en[0] = &plru_tree[~3,~1,~0]; #plru_tree[0,1,3]=={0,0,0}
+ # For each entry traverse the tree. If every tree-node matches
+ # the corresponding bit of the entry's index, this is
+ # the next entry to replace.
+ replace = []
+ for i in range(self.entries):
+ en = []
+ for lvl in range(LOG_TLB):
+ idx_base = (1<<lvl)-1
+ # lvl0 <=> MSB, lvl1 <=> MSB-1, ...
+ shift = LOG_TLB - lvl;
+ new_idx = (i >> (shift-1)) & 1;
+ plru_idx = idx_base + (i>>shift)
+ plru = Signal(reset_less=True,
+ name="plru-%d-%d-%d" % (i, lvl, plru_idx))
+ m.d.comb += plru.eq(self.plru_tree[plru_idx])
+ # en &= plru_tree_q[idx_base + (i>>shift)] == new_idx;
+ if new_idx:
+ en.append(~plru) # yes inverted (using bool())
+ else:
+ en.append(plru) # yes inverted (using bool())
+ print ("plru", i, en)
+ # boolean logic manipulation:
+ # plru0 & plru1 & plru2 == ~(~plru0 | ~plru1 | ~plru2)
+ replace.append(~Cat(*en).bool())
+ m.d.comb += self.replace_en_o.eq(Cat(*replace))
+
+ return m
+
+ def ports(self):
+ return [self.entries, self.lu_hit, self.replace_en_o,
+ self.lu_access_i, self.plru_tree, self.plru_tree_o]
--- /dev/null
+"""
+# Copyright 2018 ETH Zurich and University of Bologna.
+# Copyright and related rights are licensed under the Solderpad Hardware
+# License, Version 0.51 (the "License"); you may not use this file except in
+# compliance with the License. You may obtain a copy of the License at
+# http:#solderpad.org/licenses/SHL-0.51. Unless required by applicable law
+# or agreed to in writing, software, hardware and materials distributed under
+# this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+# CONDITIONS OF ANY KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations under the License.
+#
+# Author: David Schaffenrath, TU Graz
+# Author: Florian Zaruba, ETH Zurich
+# Date: 24.4.2017
+# Description: Hardware-PTW
+
+/* verilator lint_off WIDTH */
+import ariane_pkg::*;
+
+see linux kernel source:
+
+* "arch/riscv/include/asm/page.h"
+* "arch/riscv/include/asm/mmu_context.h"
+* "arch/riscv/Kconfig" (CONFIG_PAGE_OFFSET)
+
+"""
+
+from nmigen import Const, Signal, Cat, Module
+from nmigen.hdl.ast import ArrayProxy
+from nmigen.cli import verilog, rtlil
+from math import log2
+
+
+DCACHE_SET_ASSOC = 8
+CONFIG_L1D_SIZE = 32*1024
+DCACHE_INDEX_WIDTH = int(log2(CONFIG_L1D_SIZE / DCACHE_SET_ASSOC))
+DCACHE_TAG_WIDTH = 56 - DCACHE_INDEX_WIDTH
+
+ASID_WIDTH = 8
+
+
+class DCacheReqI:
+ def __init__(self):
+ self.address_index = Signal(DCACHE_INDEX_WIDTH)
+ self.address_tag = Signal(DCACHE_TAG_WIDTH)
+ self.data_wdata = Signal(64)
+ self.data_req = Signal()
+ self.data_we = Signal()
+ self.data_be = Signal(8)
+ self.data_size = Signal(2)
+ self.kill_req = Signal()
+ self.tag_valid = Signal()
+
+ def eq(self, inp):
+ res = []
+ for (o, i) in zip(self.ports(), inp.ports()):
+ res.append(o.eq(i))
+ return res
+
+ def ports(self):
+ return [self.address_index, self.address_tag,
+ self.data_wdata, self.data_req,
+ self.data_we, self.data_be, self.data_size,
+ self.kill_req, self.tag_valid,
+ ]
+
+class DCacheReqO:
+ def __init__(self):
+ self.data_gnt = Signal()
+ self.data_rvalid = Signal()
+ self.data_rdata = Signal(64) # actually in PTE object format
+
+ def eq(self, inp):
+ res = []
+ for (o, i) in zip(self.ports(), inp.ports()):
+ res.append(o.eq(i))
+ return res
+
+ def ports(self):
+ return [self.data_gnt, self.data_rvalid, self.data_rdata]
+
+
+class PTE: #(RecordObject):
+ def __init__(self):
+ self.v = Signal()
+ self.r = Signal()
+ self.w = Signal()
+ self.x = Signal()
+ self.u = Signal()
+ self.g = Signal()
+ self.a = Signal()
+ self.d = Signal()
+ self.rsw = Signal(2)
+ self.ppn = Signal(44)
+ self.reserved = Signal(10)
+
+ def flatten(self):
+ return Cat(*self.ports())
+
+ def eq(self, x):
+ if isinstance(x, ArrayProxy):
+ res = []
+ for o in self.ports():
+ i = getattr(x, o.name)
+ res.append(i)
+ x = Cat(*res)
+ else:
+ x = x.flatten()
+ return self.flatten().eq(x)
+
+ def __iter__(self):
+ """ order is critical so that flatten creates LSB to MSB
+ """
+ yield self.v
+ yield self.r
+ yield self.w
+ yield self.x
+ yield self.u
+ yield self.g
+ yield self.a
+ yield self.d
+ yield self.rsw
+ yield self.ppn
+ yield self.reserved
+
+ def ports(self):
+ return list(self)
+
+
+class TLBUpdate:
+ def __init__(self, asid_width):
+ self.valid = Signal() # valid flag
+ self.is_2M = Signal()
+ self.is_1G = Signal()
+ self.vpn = Signal(27)
+ self.asid = Signal(asid_width)
+ self.content = PTE()
+
+ def flatten(self):
+ return Cat(*self.ports())
+
+ def eq(self, x):
+ return self.flatten().eq(x.flatten())
+
+ def ports(self):
+ return [self.valid, self.is_2M, self.is_1G, self.vpn, self.asid] + \
+ self.content.ports()
+
+
+# SV39 defines three levels of page tables
+LVL1 = Const(0, 2) # defined to 0 so that ptw_lvl default-resets to LVL1
+LVL2 = Const(1, 2)
+LVL3 = Const(2, 2)
+
+
+class PTW:
+ def __init__(self, asid_width=8):
+ self.asid_width = asid_width
+
+ self.flush_i = Signal() # flush everything, we need to do this because
+ # actually everything we do is speculative at this stage
+ # e.g.: there could be a CSR instruction that changes everything
+ self.ptw_active_o = Signal(reset=1) # active if not IDLE
+ self.walking_instr_o = Signal() # set when walking for TLB
+ self.ptw_error_o = Signal() # set when an error occurred
+ self.enable_translation_i = Signal() # CSRs indicate to enable SV39
+ self.en_ld_st_translation_i = Signal() # enable VM translation for ld/st
+
+ self.lsu_is_store_i = Signal() # translation triggered by store
+ # PTW memory interface
+ self.req_port_i = DCacheReqO()
+ self.req_port_o = DCacheReqI()
+
+ # to TLBs, update logic
+ self.itlb_update_o = TLBUpdate(asid_width)
+ self.dtlb_update_o = TLBUpdate(asid_width)
+
+ self.update_vaddr_o = Signal(39)
+
+ self.asid_i = Signal(self.asid_width)
+ # from TLBs
+ # did we miss?
+ self.itlb_access_i = Signal()
+ self.itlb_hit_i = Signal()
+ self.itlb_vaddr_i = Signal(64)
+
+ self.dtlb_access_i = Signal()
+ self.dtlb_hit_i = Signal()
+ self.dtlb_vaddr_i = Signal(64)
+ # from CSR file
+ self.satp_ppn_i = Signal(44) # ppn from satp
+ self.mxr_i = Signal()
+ # Performance counters
+ self.itlb_miss_o = Signal()
+ self.dtlb_miss_o = Signal()
+
+ def ports(self):
+ return [self.ptw_active_o, self.walking_instr_o, self.ptw_error_o,
+ ]
+ return [
+ self.enable_translation_i, self.en_ld_st_translation_i,
+ self.lsu_is_store_i, self.req_port_i, self.req_port_o,
+ self.update_vaddr_o,
+ self.asid_i,
+ self.itlb_access_i, self.itlb_hit_i, self.itlb_vaddr_i,
+ self.dtlb_access_i, self.dtlb_hit_i, self.dtlb_vaddr_i,
+ self.satp_ppn_i, self.mxr_i,
+ self.itlb_miss_o, self.dtlb_miss_o
+ ] + self.itlb_update_o.ports() + self.dtlb_update_o.ports()
+
+ def elaborate(self, platform):
+ m = Module()
+
+ # input registers
+ data_rvalid = Signal()
+ data_rdata = Signal(64)
+
+ # NOTE: pte decodes the incoming bit-field (data_rdata). data_rdata
+ # is spec'd in 64-bit binary-format: better to spec as Record?
+ pte = PTE()
+ m.d.comb += pte.flatten().eq(data_rdata)
+
+ # SV39 defines three levels of page tables
+ ptw_lvl = Signal(2) # default=0=LVL1 on reset (see above)
+ ptw_lvl1 = Signal()
+ ptw_lvl2 = Signal()
+ ptw_lvl3 = Signal()
+ m.d.comb += [ptw_lvl1.eq(ptw_lvl == LVL1),
+ ptw_lvl2.eq(ptw_lvl == LVL2),
+ ptw_lvl3.eq(ptw_lvl == LVL3)]
+
+ # is this an instruction page table walk?
+ is_instr_ptw = Signal()
+ global_mapping = Signal()
+ # latched tag signal
+ tag_valid = Signal()
+ # register the ASID
+ tlb_update_asid = Signal(self.asid_width)
+ # register VPN we need to walk, SV39 defines a 39 bit virtual addr
+ vaddr = Signal(64)
+ # 4 byte aligned physical pointer
+ ptw_pptr = Signal(56)
+
+ end = DCACHE_INDEX_WIDTH + DCACHE_TAG_WIDTH
+ m.d.sync += [
+ # Assignments
+ self.update_vaddr_o.eq(vaddr),
+
+ self.walking_instr_o.eq(is_instr_ptw),
+ # directly output the correct physical address
+ self.req_port_o.address_index.eq(ptw_pptr[0:DCACHE_INDEX_WIDTH]),
+ self.req_port_o.address_tag.eq(ptw_pptr[DCACHE_INDEX_WIDTH:end]),
+ # we are never going to kill this request
+ self.req_port_o.kill_req.eq(0), # XXX assign comb?
+ # we are never going to write with the HPTW
+ self.req_port_o.data_wdata.eq(Const(0, 64)), # XXX assign comb?
+ # -----------
+ # TLB Update
+ # -----------
+ self.itlb_update_o.vpn.eq(vaddr[12:39]),
+ self.dtlb_update_o.vpn.eq(vaddr[12:39]),
+ # update the correct page table level
+ self.itlb_update_o.is_2M.eq(ptw_lvl2),
+ self.itlb_update_o.is_1G.eq(ptw_lvl1),
+ self.dtlb_update_o.is_2M.eq(ptw_lvl2),
+ self.dtlb_update_o.is_1G.eq(ptw_lvl1),
+ # output the correct ASID
+ self.itlb_update_o.asid.eq(tlb_update_asid),
+ self.dtlb_update_o.asid.eq(tlb_update_asid),
+ # set the global mapping bit
+ self.itlb_update_o.content.eq(pte),
+ self.itlb_update_o.content.g.eq(global_mapping),
+ self.dtlb_update_o.content.eq(pte),
+ self.dtlb_update_o.content.g.eq(global_mapping),
+
+ self.req_port_o.tag_valid.eq(tag_valid),
+ ]
+
+ #-------------------
+ # Page table walker
+ #-------------------
+ # A virtual address va is translated into a physical address pa as
+ # follows:
+ # 1. Let a be sptbr.ppn × PAGESIZE, and let i = LEVELS-1. (For Sv39,
+ # PAGESIZE=2^12 and LEVELS=3.)
+ # 2. Let pte be the value of the PTE at address a+va.vpn[i]×PTESIZE.
+ # (For Sv32, PTESIZE=4.)
+ # 3. If pte.v = 0, or if pte.r = 0 and pte.w = 1, stop and raise an
+ # access exception.
+ # 4. Otherwise, the PTE is valid. If pte.r = 1 or pte.x = 1, go to
+ # step 5. Otherwise, this PTE is a pointer to the next level of
+ # the page table.
+ # Let i=i-1. If i < 0, stop and raise an access exception.
+ # Otherwise, let a = pte.ppn × PAGESIZE and go to step 2.
+ # 5. A leaf PTE has been found. Determine if the requested memory
+ # access is allowed by the pte.r, pte.w, and pte.x bits. If not,
+ # stop and raise an access exception. Otherwise, the translation is
+ # successful. Set pte.a to 1, and, if the memory access is a
+ # store, set pte.d to 1.
+ # The translated physical address is given as follows:
+ # - pa.pgoff = va.pgoff.
+ # - If i > 0, then this is a superpage translation and
+ # pa.ppn[i-1:0] = va.vpn[i-1:0].
+ # - pa.ppn[LEVELS-1:i] = pte.ppn[LEVELS-1:i].
+ # 6. If i > 0 and pa.ppn[i − 1 : 0] != 0, this is a misaligned
+ # superpage stop and raise a page-fault exception.
+
+ m.d.sync += tag_valid.eq(0)
+
+ # default assignments
+ m.d.comb += [
+ # PTW memory interface
+ self.req_port_o.data_req.eq(0),
+ self.req_port_o.data_be.eq(Const(0xFF, 8)),
+ self.req_port_o.data_size.eq(Const(0b11, 2)),
+ self.req_port_o.data_we.eq(0),
+ self.ptw_error_o.eq(0),
+ self.itlb_update_o.valid.eq(0),
+ self.dtlb_update_o.valid.eq(0),
+
+ self.itlb_miss_o.eq(0),
+ self.dtlb_miss_o.eq(0),
+ ]
+
+ # ------------
+ # State Machine
+ # ------------
+
+ with m.FSM() as fsm:
+
+ with m.State("IDLE"):
+ self.idle(m, is_instr_ptw, ptw_lvl, global_mapping,
+ ptw_pptr, vaddr, tlb_update_asid)
+
+ with m.State("WAIT_GRANT"):
+ self.grant(m, tag_valid, data_rvalid)
+
+ with m.State("PTE_LOOKUP"):
+ # we wait for the valid signal
+ with m.If(data_rvalid):
+ self.lookup(m, pte, ptw_lvl, ptw_lvl1, ptw_lvl2, ptw_lvl3,
+ data_rvalid, global_mapping,
+ is_instr_ptw, ptw_pptr)
+
+ # Propagate error to MMU/LSU
+ with m.State("PROPAGATE_ERROR"):
+ m.next = "IDLE"
+ m.d.comb += self.ptw_error_o.eq(1)
+
+ # wait for the rvalid before going back to IDLE
+ with m.State("WAIT_RVALID"):
+ with m.If(data_rvalid):
+ m.next = "IDLE"
+
+ m.d.sync += [data_rdata.eq(self.req_port_i.data_rdata),
+ data_rvalid.eq(self.req_port_i.data_rvalid)
+ ]
+
+ return m
+
+ def set_grant_state(self, m):
+ # should we have flushed before we got an rvalid,
+ # wait for it until going back to IDLE
+ with m.If(self.flush_i):
+ with m.If (self.req_port_i.data_gnt):
+ m.next = "WAIT_RVALID"
+ with m.Else():
+ m.next = "IDLE"
+ with m.Else():
+ m.next = "WAIT_GRANT"
+
+ def idle(self, m, is_instr_ptw, ptw_lvl, global_mapping,
+ ptw_pptr, vaddr, tlb_update_asid):
+ # by default we start with the top-most page table
+ m.d.sync += [is_instr_ptw.eq(0),
+ ptw_lvl.eq(LVL1),
+ global_mapping.eq(0),
+ self.ptw_active_o.eq(0), # deactive (IDLE)
+ ]
+ # work out itlb/dtlb miss
+ m.d.comb += self.itlb_miss_o.eq(self.enable_translation_i & \
+ self.itlb_access_i & \
+ ~self.itlb_hit_i & \
+ ~self.dtlb_access_i)
+ m.d.comb += self.dtlb_miss_o.eq(self.en_ld_st_translation_i & \
+ self.dtlb_access_i & \
+ ~self.dtlb_hit_i)
+ # we got an ITLB miss?
+ with m.If(self.itlb_miss_o):
+ pptr = Cat(Const(0, 3), self.itlb_vaddr_i[30:39],
+ self.satp_ppn_i)
+ m.d.sync += [ptw_pptr.eq(pptr),
+ is_instr_ptw.eq(1),
+ vaddr.eq(self.itlb_vaddr_i),
+ tlb_update_asid.eq(self.asid_i),
+ ]
+ self.set_grant_state(m)
+
+ # we got a DTLB miss?
+ with m.Elif(self.dtlb_miss_o):
+ pptr = Cat(Const(0, 3), self.dtlb_vaddr_i[30:39],
+ self.satp_ppn_i)
+ m.d.sync += [ptw_pptr.eq(pptr),
+ vaddr.eq(self.dtlb_vaddr_i),
+ tlb_update_asid.eq(self.asid_i),
+ ]
+ self.set_grant_state(m)
+
+ def grant(self, m, tag_valid, data_rvalid):
+ # we've got a data WAIT_GRANT so tell the
+ # cache that the tag is valid
+
+ # send a request out
+ m.d.comb += self.req_port_o.data_req.eq(1)
+ # wait for the WAIT_GRANT
+ with m.If(self.req_port_i.data_gnt):
+ # send the tag valid signal one cycle later
+ m.d.sync += tag_valid.eq(1)
+ # should we have flushed before we got an rvalid,
+ # wait for it until going back to IDLE
+ with m.If(self.flush_i):
+ with m.If (~data_rvalid):
+ m.next = "WAIT_RVALID"
+ with m.Else():
+ m.next = "IDLE"
+ with m.Else():
+ m.next = "PTE_LOOKUP"
+
+ def lookup(self, m, pte, ptw_lvl, ptw_lvl1, ptw_lvl2, ptw_lvl3,
+ data_rvalid, global_mapping,
+ is_instr_ptw, ptw_pptr):
+ # temporaries
+ pte_rx = Signal(reset_less=True)
+ pte_exe = Signal(reset_less=True)
+ pte_inv = Signal(reset_less=True)
+ pte_a = Signal(reset_less=True)
+ st_wd = Signal(reset_less=True)
+ m.d.comb += [pte_rx.eq(pte.r | pte.x),
+ pte_exe.eq(~pte.x | ~pte.a),
+ pte_inv.eq(~pte.v | (~pte.r & pte.w)),
+ pte_a.eq(pte.a & (pte.r | (pte.x & self.mxr_i))),
+ st_wd.eq(self.lsu_is_store_i & (~pte.w | ~pte.d))]
+
+ l1err = Signal(reset_less=True)
+ l2err = Signal(reset_less=True)
+ m.d.comb += [l2err.eq((ptw_lvl2) & pte.ppn[0:9] != Const(0, 9)),
+ l1err.eq((ptw_lvl1) & pte.ppn[0:18] != Const(0, 18)) ]
+
+ # check if the global mapping bit is set
+ with m.If (pte.g):
+ m.d.sync += global_mapping.eq(1)
+
+ m.next = "IDLE"
+
+ # -------------
+ # Invalid PTE
+ # -------------
+ # If pte.v = 0, or if pte.r = 0 and pte.w = 1,
+ # stop and raise a page-fault exception.
+ with m.If (pte_inv):
+ m.next = "PROPAGATE_ERROR"
+
+ # -----------
+ # Valid PTE
+ # -----------
+
+ # it is a valid PTE
+ # if pte.r = 1 or pte.x = 1 it is a valid PTE
+ with m.Elif (pte_rx):
+ # Valid translation found (either 1G, 2M or 4K)
+ with m.If(is_instr_ptw):
+ # ------------
+ # Update ITLB
+ # ------------
+ # If page not executable, we can directly raise error.
+ # This doesn't put a useless entry into the TLB.
+ # The same idea applies to the access flag since we let
+ # the access flag be managed by SW.
+ with m.If (pte_exe):
+ m.next = "IDLE"
+ with m.Else():
+ m.d.comb += self.itlb_update_o.valid.eq(1)
+
+ with m.Else():
+ # ------------
+ # Update DTLB
+ # ------------
+ # Check if the access flag has been set, otherwise
+ # throw page-fault and let software handle those bits.
+ # If page not readable (there are no write-only pages)
+ # directly raise an error. This doesn't put a useless
+ # entry into the TLB.
+ with m.If(pte_a):
+ m.d.comb += self.dtlb_update_o.valid.eq(1)
+ with m.Else():
+ m.next = "PROPAGATE_ERROR"
+ # Request is a store: perform additional checks
+ # If the request was a store and the page not
+ # write-able, raise an error
+ # the same applies if the dirty flag is not set
+ with m.If (st_wd):
+ m.d.comb += self.dtlb_update_o.valid.eq(0)
+ m.next = "PROPAGATE_ERROR"
+
+ # check if the ppn is correctly aligned: Case (6)
+ with m.If(l1err | l2err):
+ m.next = "PROPAGATE_ERROR"
+ m.d.comb += [self.dtlb_update_o.valid.eq(0),
+ self.itlb_update_o.valid.eq(0)]
+
+ # this is a pointer to the next TLB level
+ with m.Else():
+ # pointer to next level of page table
+ with m.If (ptw_lvl1):
+ # we are in the second level now
+ pptr = Cat(Const(0, 3), self.dtlb_vaddr_i[21:30], pte.ppn)
+ m.d.sync += [ptw_pptr.eq(pptr),
+ ptw_lvl.eq(LVL2)
+ ]
+ with m.If(ptw_lvl2):
+ # here we received a pointer to the third level
+ pptr = Cat(Const(0, 3), self.dtlb_vaddr_i[12:21], pte.ppn)
+ m.d.sync += [ptw_pptr.eq(pptr),
+ ptw_lvl.eq(LVL3)
+ ]
+ self.set_grant_state(m)
+
+ with m.If (ptw_lvl3):
+ # Should already be the last level
+ # page table => Error
+ m.d.sync += ptw_lvl.eq(LVL3)
+ m.next = "PROPAGATE_ERROR"
+
+
+if __name__ == '__main__':
+ ptw = PTW()
+ vl = rtlil.convert(ptw, ports=ptw.ports())
+ with open("test_ptw.il", "w") as f:
+ f.write(vl)
+++ /dev/null
-from nmigen import Const
-
-INSTR_ADDR_MISALIGNED = Const(0, 64)
-INSTR_ACCESS_FAULT = Const(1, 64)
-ILLEGAL_INSTR = Const(2, 64)
-BREAKPOINT = Const(3, 64)
-LD_ADDR_MISALIGNED = Const(4, 64)
-LD_ACCESS_FAULT = Const(5, 64)
-ST_ADDR_MISALIGNED = Const(6, 64)
-ST_ACCESS_FAULT = Const(7, 64)
-ENV_CALL_UMODE = Const(8, 64) # environment call from user mode
-ENV_CALL_SMODE = Const(9, 64) # environment call from supervisor mode
-ENV_CALL_MMODE = Const(11, 64) # environment call from machine mode
-INSTR_PAGE_FAULT = Const(12, 64) # Instruction page fault
-LOAD_PAGE_FAULT = Const(13, 64) # Load page fault
-STORE_PAGE_FAULT = Const(15, 64) # Store page fault
+++ /dev/null
-"""
-# Copyright 2018 ETH Zurich and University of Bologna.
-# Copyright and related rights are licensed under the Solderpad Hardware
-# License, Version 0.51 (the "License"); you may not use this file except in
-# compliance with the License. You may obtain a copy of the License at
-# http:#solderpad.org/licenses/SHL-0.51. Unless required by applicable law
-# or agreed to in writing, software, hardware and materials distributed under
-# this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-# CONDITIONS OF ANY KIND, either express or implied. See the License for the
-# specific language governing permissions and limitations under the License.
-#
-# Author: Florian Zaruba, ETH Zurich
-# Date: 19/04/2017
-# Description: Memory Management Unit for Ariane, contains TLB and
-# address translation unit. SV39 as defined in RISC-V
-# privilege specification 1.11-WIP
-
-import ariane_pkg::*;
-"""
-
-from nmigen import Const, Signal, Cat, Module, Mux
-from nmigen.cli import verilog, rtlil
-
-from ptw import DCacheReqI, DCacheReqO, TLBUpdate, PTE, PTW
-from tlb import TLB
-from exceptcause import (INSTR_ACCESS_FAULT, INSTR_PAGE_FAULT,
- LOAD_PAGE_FAULT, STORE_PAGE_FAULT)
-
-PRIV_LVL_M = Const(0b11, 2)
-PRIV_LVL_S = Const(0b01, 2)
-PRIV_LVL_U = Const(0b00, 2)
-
-
-class RVException:
- def __init__(self):
- self.cause = Signal(64) # cause of exception
- self.tval = Signal(64) # more info of causing exception
- # (e.g.: instruction causing it),
- # address of LD/ST fault
- self.valid = Signal()
-
- def eq(self, inp):
- res = []
- for (o, i) in zip(self.ports(), inp.ports()):
- res.append(o.eq(i))
- return res
-
- def __iter__(self):
- yield self.cause
- yield self.tval
- yield self.valid
-
- def ports(self):
- return list(self)
-
-
-class ICacheReqI:
- def __init__(self):
- self.fetch_valid = Signal() # address translation valid
- self.fetch_paddr = Signal(64) # physical address in
- self.fetch_exception = RVException() # exception occurred during fetch
-
- def __iter__(self):
- yield self.fetch_valid
- yield self.fetch_paddr
- yield from self.fetch_exception
-
- def ports(self):
- return list(self)
-
-
-class ICacheReqO:
- def __init__(self):
- self.fetch_req = Signal() # address translation request
- self.fetch_vaddr = Signal(64) # virtual address out
-
- def __iter__(self):
- yield self.fetch_req
- yield self.fetch_vaddr
-
- def ports(self):
- return list(self)
-
-
-class MMU:
- def __init__(self, instr_tlb_entries = 4,
- data_tlb_entries = 4,
- asid_width = 1):
- self.instr_tlb_entries = instr_tlb_entries
- self.data_tlb_entries = data_tlb_entries
- self.asid_width = asid_width
-
- self.flush_i = Signal()
- self.enable_translation_i = Signal()
- self.en_ld_st_translation_i = Signal() # enable VM translation for LD/ST
- # IF interface
- self.icache_areq_i = ICacheReqO()
- self.icache_areq_o = ICacheReqI()
- # LSU interface
- # this is a more minimalistic interface because the actual addressing
- # logic is handled in the LSU as we distinguish load and stores,
- # what we do here is simple address translation
- self.misaligned_ex_i = RVException()
- self.lsu_req_i = Signal() # request address translation
- self.lsu_vaddr_i = Signal(64) # virtual address in
- self.lsu_is_store_i = Signal() # the translation is requested by a store
- # if we need to walk the page table we can't grant in the same cycle
-
- # Cycle 0
- self.lsu_dtlb_hit_o = Signal() # sent in the same cycle as the request
- # if translation hits in the DTLB
- # Cycle 1
- self.lsu_valid_o = Signal() # translation is valid
- self.lsu_paddr_o = Signal(64) # translated address
- self.lsu_exception_o = RVException() # addr translate threw exception
-
- # General control signals
- self.priv_lvl_i = Signal(2)
- self.ld_st_priv_lvl_i = Signal(2)
- self.sum_i = Signal()
- self.mxr_i = Signal()
- # input logic flag_mprv_i,
- self.satp_ppn_i = Signal(44)
- self.asid_i = Signal(self.asid_width)
- self.flush_tlb_i = Signal()
- # Performance counters
- self.itlb_miss_o = Signal()
- self.dtlb_miss_o = Signal()
- # PTW memory interface
- self.req_port_i = DCacheReqO()
- self.req_port_o = DCacheReqI()
-
- def elaborate(self, platform):
- m = Module()
-
- iaccess_err = Signal() # insufficient priv to access instr page
- daccess_err = Signal() # insufficient priv to access data page
- ptw_active = Signal() # PTW is currently walking a page table
- walking_instr = Signal() # PTW is walking because of an ITLB miss
- ptw_error = Signal() # PTW threw an exception
-
- update_vaddr = Signal(39)
- uaddr64 = Cat(update_vaddr, Const(0, 25)) # extend to 64bit with zeros
- update_ptw_itlb = TLBUpdate(self.asid_width)
- update_ptw_dtlb = TLBUpdate(self.asid_width)
-
- itlb_lu_access = Signal()
- itlb_content = PTE()
- itlb_is_2M = Signal()
- itlb_is_1G = Signal()
- itlb_lu_hit = Signal()
-
- dtlb_lu_access = Signal()
- dtlb_content = PTE()
- dtlb_is_2M = Signal()
- dtlb_is_1G = Signal()
- dtlb_lu_hit = Signal()
-
- # Assignments
- m.d.comb += [itlb_lu_access.eq(self.icache_areq_i.fetch_req),
- dtlb_lu_access.eq(self.lsu_req_i)
- ]
-
- # ITLB
- m.submodules.i_tlb = i_tlb = TLB(self.instr_tlb_entries,
- self.asid_width)
- m.d.comb += [i_tlb.flush_i.eq(self.flush_tlb_i),
- i_tlb.update_i.eq(update_ptw_itlb),
- i_tlb.lu_access_i.eq(itlb_lu_access),
- i_tlb.lu_asid_i.eq(self.asid_i),
- i_tlb.lu_vaddr_i.eq(self.icache_areq_i.fetch_vaddr),
- itlb_content.eq(i_tlb.lu_content_o),
- itlb_is_2M.eq(i_tlb.lu_is_2M_o),
- itlb_is_1G.eq(i_tlb.lu_is_1G_o),
- itlb_lu_hit.eq(i_tlb.lu_hit_o),
- ]
-
- # DTLB
- m.submodules.d_tlb = d_tlb = TLB(self.data_tlb_entries,
- self.asid_width)
- m.d.comb += [d_tlb.flush_i.eq(self.flush_tlb_i),
- d_tlb.update_i.eq(update_ptw_dtlb),
- d_tlb.lu_access_i.eq(dtlb_lu_access),
- d_tlb.lu_asid_i.eq(self.asid_i),
- d_tlb.lu_vaddr_i.eq(self.lsu_vaddr_i),
- dtlb_content.eq(d_tlb.lu_content_o),
- dtlb_is_2M.eq(d_tlb.lu_is_2M_o),
- dtlb_is_1G.eq(d_tlb.lu_is_1G_o),
- dtlb_lu_hit.eq(d_tlb.lu_hit_o),
- ]
-
- # PTW
- m.submodules.ptw = ptw = PTW(self.asid_width)
- m.d.comb += [ptw_active.eq(ptw.ptw_active_o),
- walking_instr.eq(ptw.walking_instr_o),
- ptw_error.eq(ptw.ptw_error_o),
- ptw.enable_translation_i.eq(self.enable_translation_i),
-
- update_vaddr.eq(ptw.update_vaddr_o),
- update_ptw_itlb.eq(ptw.itlb_update_o),
- update_ptw_dtlb.eq(ptw.dtlb_update_o),
-
- ptw.itlb_access_i.eq(itlb_lu_access),
- ptw.itlb_hit_i.eq(itlb_lu_hit),
- ptw.itlb_vaddr_i.eq(self.icache_areq_i.fetch_vaddr),
-
- ptw.dtlb_access_i.eq(dtlb_lu_access),
- ptw.dtlb_hit_i.eq(dtlb_lu_hit),
- ptw.dtlb_vaddr_i.eq(self.lsu_vaddr_i),
-
- ptw.req_port_i.eq(self.req_port_i),
- self.req_port_o.eq(ptw.req_port_o),
- ]
-
- # ila_1 i_ila_1 (
- # .clk(clk_i), # input wire clk
- # .probe0({req_port_o.address_tag, req_port_o.address_index}),
- # .probe1(req_port_o.data_req), # input wire [63:0] probe1
- # .probe2(req_port_i.data_gnt), # input wire [0:0] probe2
- # .probe3(req_port_i.data_rdata), # input wire [0:0] probe3
- # .probe4(req_port_i.data_rvalid), # input wire [0:0] probe4
- # .probe5(ptw_error), # input wire [1:0] probe5
- # .probe6(update_vaddr), # input wire [0:0] probe6
- # .probe7(update_ptw_itlb.valid), # input wire [0:0] probe7
- # .probe8(update_ptw_dtlb.valid), # input wire [0:0] probe8
- # .probe9(dtlb_lu_access), # input wire [0:0] probe9
- # .probe10(lsu_vaddr_i), # input wire [0:0] probe10
- # .probe11(dtlb_lu_hit), # input wire [0:0] probe11
- # .probe12(itlb_lu_access), # input wire [0:0] probe12
- # .probe13(icache_areq_i.fetch_vaddr), # input wire [0:0] probe13
- # .probe14(itlb_lu_hit) # input wire [0:0] probe13
- # );
-
- #-----------------------
- # Instruction Interface
- #-----------------------
- # The instruction interface is a simple request response interface
-
- # MMU disabled: just pass through
- m.d.comb += [self.icache_areq_o.fetch_valid.eq(
- self.icache_areq_i.fetch_req),
- # play through in case we disabled address translation
- self.icache_areq_o.fetch_paddr.eq(
- self.icache_areq_i.fetch_vaddr)
- ]
- # two potential exception sources:
- # 1. HPTW threw an exception -> signal with a page fault exception
- # 2. We got an access error because of insufficient permissions ->
- # throw an access exception
- m.d.comb += self.icache_areq_o.fetch_exception.valid.eq(0)
- # Check whether we are allowed to access this memory region
- # from a fetch perspective
-
- # XXX TODO: use PermissionValidator instead [we like modules]
- m.d.comb += iaccess_err.eq(self.icache_areq_i.fetch_req & \
- (((self.priv_lvl_i == PRIV_LVL_U) & \
- ~itlb_content.u) | \
- ((self.priv_lvl_i == PRIV_LVL_S) & \
- itlb_content.u)))
-
- # MMU enabled: address from TLB, request delayed until hit.
- # Error when TLB hit and no access right or TLB hit and
- # translated address not valid (e.g. AXI decode error),
- # or when PTW performs walk due to ITLB miss and raises
- # an error.
- with m.If (self.enable_translation_i):
- # we work with SV39, so if VM is enabled, check that
- # all bits [63:38] are equal
- with m.If (self.icache_areq_i.fetch_req & \
- ~(((~self.icache_areq_i.fetch_vaddr[38:64]) == 0) | \
- (self.icache_areq_i.fetch_vaddr[38:64]) == 0)):
- fe = self.icache_areq_o.fetch_exception
- m.d.comb += [fe.cause.eq(INSTR_ACCESS_FAULT),
- fe.tval.eq(self.icache_areq_i.fetch_vaddr),
- fe.valid.eq(1)
- ]
-
- m.d.comb += self.icache_areq_o.fetch_valid.eq(0)
-
- # 4K page
- paddr = Signal.like(self.icache_areq_o.fetch_paddr)
- paddr4k = Cat(self.icache_areq_i.fetch_vaddr[0:12],
- itlb_content.ppn)
- m.d.comb += paddr.eq(paddr4k)
- # Mega page
- with m.If(itlb_is_2M):
- m.d.comb += paddr[12:21].eq(
- self.icache_areq_i.fetch_vaddr[12:21])
- # Giga page
- with m.If(itlb_is_1G):
- m.d.comb += paddr[12:30].eq(
- self.icache_areq_i.fetch_vaddr[12:30])
- m.d.comb += self.icache_areq_o.fetch_paddr.eq(paddr)
-
- # ---------
- # ITLB Hit
- # --------
- # if we hit the ITLB output the request signal immediately
- with m.If(itlb_lu_hit):
- m.d.comb += self.icache_areq_o.fetch_valid.eq(
- self.icache_areq_i.fetch_req)
- # we got an access error
- with m.If (iaccess_err):
- # throw a page fault
- fe = self.icache_areq_o.fetch_exception
- m.d.comb += [fe.cause.eq(INSTR_ACCESS_FAULT),
- fe.tval.eq(self.icache_areq_i.fetch_vaddr),
- fe.valid.eq(1)
- ]
- # ---------
- # ITLB Miss
- # ---------
- # watch out for exceptions happening during walking the page table
- with m.Elif(ptw_active & walking_instr):
- m.d.comb += self.icache_areq_o.fetch_valid.eq(ptw_error)
- fe = self.icache_areq_o.fetch_exception
- m.d.comb += [fe.cause.eq(INSTR_PAGE_FAULT),
- fe.tval.eq(uaddr64),
- fe.valid.eq(1)
- ]
-
- #-----------------------
- # Data Interface
- #-----------------------
-
- lsu_vaddr = Signal(64)
- dtlb_pte = PTE()
- misaligned_ex = RVException()
- lsu_req = Signal()
- lsu_is_store = Signal()
- dtlb_hit = Signal()
- dtlb_is_2M = Signal()
- dtlb_is_1G = Signal()
-
- # check if we need to do translation or if we are always
- # ready (e.g.: we are not translating anything)
- m.d.comb += self.lsu_dtlb_hit_o.eq(Mux(self.en_ld_st_translation_i,
- dtlb_lu_hit, 1))
-
- # The data interface is simpler and only consists of a
- # request/response interface
- m.d.comb += [
- # save request and DTLB response
- lsu_vaddr.eq(self.lsu_vaddr_i),
- lsu_req.eq(self.lsu_req_i),
- misaligned_ex.eq(self.misaligned_ex_i),
- dtlb_pte.eq(dtlb_content),
- dtlb_hit.eq(dtlb_lu_hit),
- lsu_is_store.eq(self.lsu_is_store_i),
- dtlb_is_2M.eq(dtlb_is_2M),
- dtlb_is_1G.eq(dtlb_is_1G),
- ]
- m.d.sync += [
- self.lsu_paddr_o.eq(lsu_vaddr),
- self.lsu_valid_o.eq(lsu_req),
- self.lsu_exception_o.eq(misaligned_ex),
- ]
-
- sverr = Signal()
- usrerr = Signal()
-
- m.d.comb += [
- # mute misaligned exceptions if there is no request
- # otherwise they will throw accidental exceptions
- misaligned_ex.valid.eq(self.misaligned_ex_i.valid & self.lsu_req_i),
-
- # SUM is not set and we are trying to access a user
- # page in supervisor mode
- sverr.eq(self.ld_st_priv_lvl_i == PRIV_LVL_S & ~self.sum_i & \
- dtlb_pte.u),
- # this is not a user page but we are in user mode and
- # trying to access it
- usrerr.eq(self.ld_st_priv_lvl_i == PRIV_LVL_U & ~dtlb_pte.u),
-
- # Check if the User flag is set, then we may only
- # access it in supervisor mode if SUM is enabled
- daccess_err.eq(sverr | usrerr),
- ]
-
- # translation is enabled and no misaligned exception occurred
- with m.If(self.en_ld_st_translation_i & ~misaligned_ex.valid):
- m.d.comb += lsu_req.eq(0)
- # 4K page
- paddr = Signal.like(lsu_vaddr)
- paddr4k = Cat(lsu_vaddr[0:12], itlb_content.ppn)
- m.d.comb += paddr.eq(paddr4k)
- # Mega page
- with m.If(dtlb_is_2M):
- m.d.comb += paddr[12:21].eq(lsu_vaddr[12:21])
- # Giga page
- with m.If(dtlb_is_1G):
- m.d.comb += paddr[12:30].eq(lsu_vaddr[12:30])
- m.d.sync += self.lsu_paddr_o.eq(paddr)
-
- # ---------
- # DTLB Hit
- # --------
- with m.If(dtlb_hit & lsu_req):
- m.d.comb += lsu_req.eq(1)
- # this is a store
- with m.If (lsu_is_store):
- # check if the page is write-able and
- # we are not violating privileges
- # also check if the dirty flag is set
- with m.If(~dtlb_pte.w | daccess_err | ~dtlb_pte.d):
- le = self.lsu_exception_o
- m.d.sync += [le.cause.eq(STORE_PAGE_FAULT),
- le.tval.eq(lsu_vaddr),
- le.valid.eq(1)
- ]
-
- # this is a load, check for sufficient access
- # privileges - throw a page fault if necessary
- with m.Elif(daccess_err):
- le = self.lsu_exception_o
- m.d.sync += [le.cause.eq(LOAD_PAGE_FAULT),
- le.tval.eq(lsu_vaddr),
- le.valid.eq(1)
- ]
- # ---------
- # DTLB Miss
- # ---------
- # watch out for exceptions
- with m.Elif (ptw_active & ~walking_instr):
- # page table walker threw an exception
- with m.If (ptw_error):
- # an error makes the translation valid
- m.d.comb += lsu_req.eq(1)
- # the page table walker can only throw page faults
- with m.If (lsu_is_store):
- le = self.lsu_exception_o
- m.d.sync += [le.cause.eq(STORE_PAGE_FAULT),
- le.tval.eq(uaddr64),
- le.valid.eq(1)
- ]
- with m.Else():
- m.d.sync += [le.cause.eq(LOAD_PAGE_FAULT),
- le.tval.eq(uaddr64),
- le.valid.eq(1)
- ]
-
- return m
-
- def ports(self):
- return [self.flush_i, self.enable_translation_i,
- self.en_ld_st_translation_i,
- self.lsu_req_i,
- self.lsu_vaddr_i, self.lsu_is_store_i, self.lsu_dtlb_hit_o,
- self.lsu_valid_o, self.lsu_paddr_o,
- self.priv_lvl_i, self.ld_st_priv_lvl_i, self.sum_i, self.mxr_i,
- self.satp_ppn_i, self.asid_i, self.flush_tlb_i,
- self.itlb_miss_o, self.dtlb_miss_o] + \
- self.icache_areq_i.ports() + self.icache_areq_o.ports() + \
- self.req_port_i.ports() + self.req_port_o.ports() + \
- self.misaligned_ex_i.ports() + self.lsu_exception_o.ports()
-
-if __name__ == '__main__':
- mmu = MMU()
- vl = rtlil.convert(mmu, ports=mmu.ports())
- with open("test_mmu.il", "w") as f:
- f.write(vl)
-
+++ /dev/null
-from nmigen import Signal, Module, Cat, Const
-from nmigen.hdl.ir import Elaboratable
-from math import log2
-
-from ptw import TLBUpdate, PTE, ASID_WIDTH
-
-class PLRU(Elaboratable):
- """ PLRU - Pseudo Least Recently Used Replacement
-
- PLRU-tree indexing:
- lvl0 0
- / \
- / \
- lvl1 1 2
- / \ / \
- lvl2 3 4 5 6
- / \ /\/\ /\
- ... ... ... ...
- """
- def __init__(self, entries):
- self.entries = entries
- self.lu_hit = Signal(entries)
- self.replace_en_o = Signal(entries)
- self.lu_access_i = Signal()
- # Tree (bit per entry)
- self.TLBSZ = 2*(self.entries-1)
- self.plru_tree = Signal(self.TLBSZ)
- self.plru_tree_o = Signal(self.TLBSZ)
-
- def elaborate(self, platform=None):
- m = Module()
-
- # Just predefine which nodes will be set/cleared
- # E.g. for a TLB with 8 entries, the for-loop is semantically
- # equivalent to the following pseudo-code:
- # unique case (1'b1)
- # lu_hit[7]: plru_tree[0, 2, 6] = {1, 1, 1};
- # lu_hit[6]: plru_tree[0, 2, 6] = {1, 1, 0};
- # lu_hit[5]: plru_tree[0, 2, 5] = {1, 0, 1};
- # lu_hit[4]: plru_tree[0, 2, 5] = {1, 0, 0};
- # lu_hit[3]: plru_tree[0, 1, 4] = {0, 1, 1};
- # lu_hit[2]: plru_tree[0, 1, 4] = {0, 1, 0};
- # lu_hit[1]: plru_tree[0, 1, 3] = {0, 0, 1};
- # lu_hit[0]: plru_tree[0, 1, 3] = {0, 0, 0};
- # default: begin /* No hit */ end
- # endcase
- LOG_TLB = int(log2(self.entries))
- print(LOG_TLB)
- for i in range(self.entries):
- # we got a hit so update the pointer as it was least recently used
- hit = Signal(reset_less=True)
- m.d.comb += hit.eq(self.lu_hit[i] & self.lu_access_i)
- with m.If(hit):
- # Set the nodes to the values we would expect
- for lvl in range(LOG_TLB):
- idx_base = (1<<lvl)-1
- # lvl0 <=> MSB, lvl1 <=> MSB-1, ...
- shift = LOG_TLB - lvl;
- new_idx = Const(~((i >> (shift-1)) & 1), (1, False))
- plru_idx = idx_base + (i >> shift)
- print ("plru", i, lvl, hex(idx_base),
- plru_idx, shift, new_idx)
- m.d.comb += self.plru_tree_o[plru_idx].eq(new_idx)
-
- # Decode tree to write enable signals
- # Next for-loop basically creates the following logic for e.g.
- # an 8 entry TLB (note: pseudo-code obviously):
- # replace_en[7] = &plru_tree[ 6, 2, 0]; #plru_tree[0,2,6]=={1,1,1}
- # replace_en[6] = &plru_tree[~6, 2, 0]; #plru_tree[0,2,6]=={1,1,0}
- # replace_en[5] = &plru_tree[ 5,~2, 0]; #plru_tree[0,2,5]=={1,0,1}
- # replace_en[4] = &plru_tree[~5,~2, 0]; #plru_tree[0,2,5]=={1,0,0}
- # replace_en[3] = &plru_tree[ 4, 1,~0]; #plru_tree[0,1,4]=={0,1,1}
- # replace_en[2] = &plru_tree[~4, 1,~0]; #plru_tree[0,1,4]=={0,1,0}
- # replace_en[1] = &plru_tree[ 3,~1,~0]; #plru_tree[0,1,3]=={0,0,1}
- # replace_en[0] = &plru_tree[~3,~1,~0]; #plru_tree[0,1,3]=={0,0,0}
- # For each entry traverse the tree. If every tree-node matches
- # the corresponding bit of the entry's index, this is
- # the next entry to replace.
- replace = []
- for i in range(self.entries):
- en = []
- for lvl in range(LOG_TLB):
- idx_base = (1<<lvl)-1
- # lvl0 <=> MSB, lvl1 <=> MSB-1, ...
- shift = LOG_TLB - lvl;
- new_idx = (i >> (shift-1)) & 1;
- plru_idx = idx_base + (i>>shift)
- plru = Signal(reset_less=True,
- name="plru-%d-%d-%d" % (i, lvl, plru_idx))
- m.d.comb += plru.eq(self.plru_tree[plru_idx])
- # en &= plru_tree_q[idx_base + (i>>shift)] == new_idx;
- if new_idx:
- en.append(~plru) # yes inverted (using bool())
- else:
- en.append(plru) # yes inverted (using bool())
- print ("plru", i, en)
- # boolean logic manipulation:
- # plru0 & plru1 & plru2 == ~(~plru0 | ~plru1 | ~plru2)
- replace.append(~Cat(*en).bool())
- m.d.comb += self.replace_en_o.eq(Cat(*replace))
-
- return m
-
- def ports(self):
- return [self.entries, self.lu_hit, self.replace_en_o,
- self.lu_access_i, self.plru_tree, self.plru_tree_o]
\ No newline at end of file
+++ /dev/null
-"""
-# Copyright 2018 ETH Zurich and University of Bologna.
-# Copyright and related rights are licensed under the Solderpad Hardware
-# License, Version 0.51 (the "License"); you may not use this file except in
-# compliance with the License. You may obtain a copy of the License at
-# http:#solderpad.org/licenses/SHL-0.51. Unless required by applicable law
-# or agreed to in writing, software, hardware and materials distributed under
-# this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-# CONDITIONS OF ANY KIND, either express or implied. See the License for the
-# specific language governing permissions and limitations under the License.
-#
-# Author: David Schaffenrath, TU Graz
-# Author: Florian Zaruba, ETH Zurich
-# Date: 24.4.2017
-# Description: Hardware-PTW
-
-/* verilator lint_off WIDTH */
-import ariane_pkg::*;
-
-see linux kernel source:
-
-* "arch/riscv/include/asm/page.h"
-* "arch/riscv/include/asm/mmu_context.h"
-* "arch/riscv/Kconfig" (CONFIG_PAGE_OFFSET)
-
-"""
-
-from nmigen import Const, Signal, Cat, Module
-from nmigen.hdl.ast import ArrayProxy
-from nmigen.cli import verilog, rtlil
-from math import log2
-
-
-DCACHE_SET_ASSOC = 8
-CONFIG_L1D_SIZE = 32*1024
-DCACHE_INDEX_WIDTH = int(log2(CONFIG_L1D_SIZE / DCACHE_SET_ASSOC))
-DCACHE_TAG_WIDTH = 56 - DCACHE_INDEX_WIDTH
-
-ASID_WIDTH = 8
-
-
-class DCacheReqI:
- def __init__(self):
- self.address_index = Signal(DCACHE_INDEX_WIDTH)
- self.address_tag = Signal(DCACHE_TAG_WIDTH)
- self.data_wdata = Signal(64)
- self.data_req = Signal()
- self.data_we = Signal()
- self.data_be = Signal(8)
- self.data_size = Signal(2)
- self.kill_req = Signal()
- self.tag_valid = Signal()
-
- def eq(self, inp):
- res = []
- for (o, i) in zip(self.ports(), inp.ports()):
- res.append(o.eq(i))
- return res
-
- def ports(self):
- return [self.address_index, self.address_tag,
- self.data_wdata, self.data_req,
- self.data_we, self.data_be, self.data_size,
- self.kill_req, self.tag_valid,
- ]
-
-class DCacheReqO:
- def __init__(self):
- self.data_gnt = Signal()
- self.data_rvalid = Signal()
- self.data_rdata = Signal(64) # actually in PTE object format
-
- def eq(self, inp):
- res = []
- for (o, i) in zip(self.ports(), inp.ports()):
- res.append(o.eq(i))
- return res
-
- def ports(self):
- return [self.data_gnt, self.data_rvalid, self.data_rdata]
-
-
-class PTE: #(RecordObject):
- def __init__(self):
- self.v = Signal()
- self.r = Signal()
- self.w = Signal()
- self.x = Signal()
- self.u = Signal()
- self.g = Signal()
- self.a = Signal()
- self.d = Signal()
- self.rsw = Signal(2)
- self.ppn = Signal(44)
- self.reserved = Signal(10)
-
- def flatten(self):
- return Cat(*self.ports())
-
- def eq(self, x):
- if isinstance(x, ArrayProxy):
- res = []
- for o in self.ports():
- i = getattr(x, o.name)
- res.append(i)
- x = Cat(*res)
- else:
- x = x.flatten()
- return self.flatten().eq(x)
-
- def __iter__(self):
- """ order is critical so that flatten creates LSB to MSB
- """
- yield self.v
- yield self.r
- yield self.w
- yield self.x
- yield self.u
- yield self.g
- yield self.a
- yield self.d
- yield self.rsw
- yield self.ppn
- yield self.reserved
-
- def ports(self):
- return list(self)
-
-
-class TLBUpdate:
- def __init__(self, asid_width):
- self.valid = Signal() # valid flag
- self.is_2M = Signal()
- self.is_1G = Signal()
- self.vpn = Signal(27)
- self.asid = Signal(asid_width)
- self.content = PTE()
-
- def flatten(self):
- return Cat(*self.ports())
-
- def eq(self, x):
- return self.flatten().eq(x.flatten())
-
- def ports(self):
- return [self.valid, self.is_2M, self.is_1G, self.vpn, self.asid] + \
- self.content.ports()
-
-
-# SV39 defines three levels of page tables
-LVL1 = Const(0, 2) # defined to 0 so that ptw_lvl default-resets to LVL1
-LVL2 = Const(1, 2)
-LVL3 = Const(2, 2)
-
-
-class PTW:
- def __init__(self, asid_width=8):
- self.asid_width = asid_width
-
- self.flush_i = Signal() # flush everything, we need to do this because
- # actually everything we do is speculative at this stage
- # e.g.: there could be a CSR instruction that changes everything
- self.ptw_active_o = Signal(reset=1) # active if not IDLE
- self.walking_instr_o = Signal() # set when walking for TLB
- self.ptw_error_o = Signal() # set when an error occurred
- self.enable_translation_i = Signal() # CSRs indicate to enable SV39
- self.en_ld_st_translation_i = Signal() # enable VM translation for ld/st
-
- self.lsu_is_store_i = Signal() # translation triggered by store
- # PTW memory interface
- self.req_port_i = DCacheReqO()
- self.req_port_o = DCacheReqI()
-
- # to TLBs, update logic
- self.itlb_update_o = TLBUpdate(asid_width)
- self.dtlb_update_o = TLBUpdate(asid_width)
-
- self.update_vaddr_o = Signal(39)
-
- self.asid_i = Signal(self.asid_width)
- # from TLBs
- # did we miss?
- self.itlb_access_i = Signal()
- self.itlb_hit_i = Signal()
- self.itlb_vaddr_i = Signal(64)
-
- self.dtlb_access_i = Signal()
- self.dtlb_hit_i = Signal()
- self.dtlb_vaddr_i = Signal(64)
- # from CSR file
- self.satp_ppn_i = Signal(44) # ppn from satp
- self.mxr_i = Signal()
- # Performance counters
- self.itlb_miss_o = Signal()
- self.dtlb_miss_o = Signal()
-
- def ports(self):
- return [self.ptw_active_o, self.walking_instr_o, self.ptw_error_o,
- ]
- return [
- self.enable_translation_i, self.en_ld_st_translation_i,
- self.lsu_is_store_i, self.req_port_i, self.req_port_o,
- self.update_vaddr_o,
- self.asid_i,
- self.itlb_access_i, self.itlb_hit_i, self.itlb_vaddr_i,
- self.dtlb_access_i, self.dtlb_hit_i, self.dtlb_vaddr_i,
- self.satp_ppn_i, self.mxr_i,
- self.itlb_miss_o, self.dtlb_miss_o
- ] + self.itlb_update_o.ports() + self.dtlb_update_o.ports()
-
- def elaborate(self, platform):
- m = Module()
-
- # input registers
- data_rvalid = Signal()
- data_rdata = Signal(64)
-
- # NOTE: pte decodes the incoming bit-field (data_rdata). data_rdata
- # is spec'd in 64-bit binary-format: better to spec as Record?
- pte = PTE()
- m.d.comb += pte.flatten().eq(data_rdata)
-
- # SV39 defines three levels of page tables
- ptw_lvl = Signal(2) # default=0=LVL1 on reset (see above)
- ptw_lvl1 = Signal()
- ptw_lvl2 = Signal()
- ptw_lvl3 = Signal()
- m.d.comb += [ptw_lvl1.eq(ptw_lvl == LVL1),
- ptw_lvl2.eq(ptw_lvl == LVL2),
- ptw_lvl3.eq(ptw_lvl == LVL3)]
-
- # is this an instruction page table walk?
- is_instr_ptw = Signal()
- global_mapping = Signal()
- # latched tag signal
- tag_valid = Signal()
- # register the ASID
- tlb_update_asid = Signal(self.asid_width)
- # register VPN we need to walk, SV39 defines a 39 bit virtual addr
- vaddr = Signal(64)
- # 4 byte aligned physical pointer
- ptw_pptr = Signal(56)
-
- end = DCACHE_INDEX_WIDTH + DCACHE_TAG_WIDTH
- m.d.sync += [
- # Assignments
- self.update_vaddr_o.eq(vaddr),
-
- self.walking_instr_o.eq(is_instr_ptw),
- # directly output the correct physical address
- self.req_port_o.address_index.eq(ptw_pptr[0:DCACHE_INDEX_WIDTH]),
- self.req_port_o.address_tag.eq(ptw_pptr[DCACHE_INDEX_WIDTH:end]),
- # we are never going to kill this request
- self.req_port_o.kill_req.eq(0), # XXX assign comb?
- # we are never going to write with the HPTW
- self.req_port_o.data_wdata.eq(Const(0, 64)), # XXX assign comb?
- # -----------
- # TLB Update
- # -----------
- self.itlb_update_o.vpn.eq(vaddr[12:39]),
- self.dtlb_update_o.vpn.eq(vaddr[12:39]),
- # update the correct page table level
- self.itlb_update_o.is_2M.eq(ptw_lvl2),
- self.itlb_update_o.is_1G.eq(ptw_lvl1),
- self.dtlb_update_o.is_2M.eq(ptw_lvl2),
- self.dtlb_update_o.is_1G.eq(ptw_lvl1),
- # output the correct ASID
- self.itlb_update_o.asid.eq(tlb_update_asid),
- self.dtlb_update_o.asid.eq(tlb_update_asid),
- # set the global mapping bit
- self.itlb_update_o.content.eq(pte),
- self.itlb_update_o.content.g.eq(global_mapping),
- self.dtlb_update_o.content.eq(pte),
- self.dtlb_update_o.content.g.eq(global_mapping),
-
- self.req_port_o.tag_valid.eq(tag_valid),
- ]
-
- #-------------------
- # Page table walker
- #-------------------
- # A virtual address va is translated into a physical address pa as
- # follows:
- # 1. Let a be sptbr.ppn × PAGESIZE, and let i = LEVELS-1. (For Sv39,
- # PAGESIZE=2^12 and LEVELS=3.)
- # 2. Let pte be the value of the PTE at address a+va.vpn[i]×PTESIZE.
- # (For Sv32, PTESIZE=4.)
- # 3. If pte.v = 0, or if pte.r = 0 and pte.w = 1, stop and raise an
- # access exception.
- # 4. Otherwise, the PTE is valid. If pte.r = 1 or pte.x = 1, go to
- # step 5. Otherwise, this PTE is a pointer to the next level of
- # the page table.
- # Let i=i-1. If i < 0, stop and raise an access exception.
- # Otherwise, let a = pte.ppn × PAGESIZE and go to step 2.
- # 5. A leaf PTE has been found. Determine if the requested memory
- # access is allowed by the pte.r, pte.w, and pte.x bits. If not,
- # stop and raise an access exception. Otherwise, the translation is
- # successful. Set pte.a to 1, and, if the memory access is a
- # store, set pte.d to 1.
- # The translated physical address is given as follows:
- # - pa.pgoff = va.pgoff.
- # - If i > 0, then this is a superpage translation and
- # pa.ppn[i-1:0] = va.vpn[i-1:0].
- # - pa.ppn[LEVELS-1:i] = pte.ppn[LEVELS-1:i].
- # 6. If i > 0 and pa.ppn[i − 1 : 0] != 0, this is a misaligned
- # superpage stop and raise a page-fault exception.
-
- m.d.sync += tag_valid.eq(0)
-
- # default assignments
- m.d.comb += [
- # PTW memory interface
- self.req_port_o.data_req.eq(0),
- self.req_port_o.data_be.eq(Const(0xFF, 8)),
- self.req_port_o.data_size.eq(Const(0b11, 2)),
- self.req_port_o.data_we.eq(0),
- self.ptw_error_o.eq(0),
- self.itlb_update_o.valid.eq(0),
- self.dtlb_update_o.valid.eq(0),
-
- self.itlb_miss_o.eq(0),
- self.dtlb_miss_o.eq(0),
- ]
-
- # ------------
- # State Machine
- # ------------
-
- with m.FSM() as fsm:
-
- with m.State("IDLE"):
- self.idle(m, is_instr_ptw, ptw_lvl, global_mapping,
- ptw_pptr, vaddr, tlb_update_asid)
-
- with m.State("WAIT_GRANT"):
- self.grant(m, tag_valid, data_rvalid)
-
- with m.State("PTE_LOOKUP"):
- # we wait for the valid signal
- with m.If(data_rvalid):
- self.lookup(m, pte, ptw_lvl, ptw_lvl1, ptw_lvl2, ptw_lvl3,
- data_rvalid, global_mapping,
- is_instr_ptw, ptw_pptr)
-
- # Propagate error to MMU/LSU
- with m.State("PROPAGATE_ERROR"):
- m.next = "IDLE"
- m.d.comb += self.ptw_error_o.eq(1)
-
- # wait for the rvalid before going back to IDLE
- with m.State("WAIT_RVALID"):
- with m.If(data_rvalid):
- m.next = "IDLE"
-
- m.d.sync += [data_rdata.eq(self.req_port_i.data_rdata),
- data_rvalid.eq(self.req_port_i.data_rvalid)
- ]
-
- return m
-
- def set_grant_state(self, m):
- # should we have flushed before we got an rvalid,
- # wait for it until going back to IDLE
- with m.If(self.flush_i):
- with m.If (self.req_port_i.data_gnt):
- m.next = "WAIT_RVALID"
- with m.Else():
- m.next = "IDLE"
- with m.Else():
- m.next = "WAIT_GRANT"
-
- def idle(self, m, is_instr_ptw, ptw_lvl, global_mapping,
- ptw_pptr, vaddr, tlb_update_asid):
- # by default we start with the top-most page table
- m.d.sync += [is_instr_ptw.eq(0),
- ptw_lvl.eq(LVL1),
- global_mapping.eq(0),
- self.ptw_active_o.eq(0), # deactive (IDLE)
- ]
- # work out itlb/dtlb miss
- m.d.comb += self.itlb_miss_o.eq(self.enable_translation_i & \
- self.itlb_access_i & \
- ~self.itlb_hit_i & \
- ~self.dtlb_access_i)
- m.d.comb += self.dtlb_miss_o.eq(self.en_ld_st_translation_i & \
- self.dtlb_access_i & \
- ~self.dtlb_hit_i)
- # we got an ITLB miss?
- with m.If(self.itlb_miss_o):
- pptr = Cat(Const(0, 3), self.itlb_vaddr_i[30:39],
- self.satp_ppn_i)
- m.d.sync += [ptw_pptr.eq(pptr),
- is_instr_ptw.eq(1),
- vaddr.eq(self.itlb_vaddr_i),
- tlb_update_asid.eq(self.asid_i),
- ]
- self.set_grant_state(m)
-
- # we got a DTLB miss?
- with m.Elif(self.dtlb_miss_o):
- pptr = Cat(Const(0, 3), self.dtlb_vaddr_i[30:39],
- self.satp_ppn_i)
- m.d.sync += [ptw_pptr.eq(pptr),
- vaddr.eq(self.dtlb_vaddr_i),
- tlb_update_asid.eq(self.asid_i),
- ]
- self.set_grant_state(m)
-
- def grant(self, m, tag_valid, data_rvalid):
- # we've got a data WAIT_GRANT so tell the
- # cache that the tag is valid
-
- # send a request out
- m.d.comb += self.req_port_o.data_req.eq(1)
- # wait for the WAIT_GRANT
- with m.If(self.req_port_i.data_gnt):
- # send the tag valid signal one cycle later
- m.d.sync += tag_valid.eq(1)
- # should we have flushed before we got an rvalid,
- # wait for it until going back to IDLE
- with m.If(self.flush_i):
- with m.If (~data_rvalid):
- m.next = "WAIT_RVALID"
- with m.Else():
- m.next = "IDLE"
- with m.Else():
- m.next = "PTE_LOOKUP"
-
- def lookup(self, m, pte, ptw_lvl, ptw_lvl1, ptw_lvl2, ptw_lvl3,
- data_rvalid, global_mapping,
- is_instr_ptw, ptw_pptr):
- # temporaries
- pte_rx = Signal(reset_less=True)
- pte_exe = Signal(reset_less=True)
- pte_inv = Signal(reset_less=True)
- pte_a = Signal(reset_less=True)
- st_wd = Signal(reset_less=True)
- m.d.comb += [pte_rx.eq(pte.r | pte.x),
- pte_exe.eq(~pte.x | ~pte.a),
- pte_inv.eq(~pte.v | (~pte.r & pte.w)),
- pte_a.eq(pte.a & (pte.r | (pte.x & self.mxr_i))),
- st_wd.eq(self.lsu_is_store_i & (~pte.w | ~pte.d))]
-
- l1err = Signal(reset_less=True)
- l2err = Signal(reset_less=True)
- m.d.comb += [l2err.eq((ptw_lvl2) & pte.ppn[0:9] != Const(0, 9)),
- l1err.eq((ptw_lvl1) & pte.ppn[0:18] != Const(0, 18)) ]
-
- # check if the global mapping bit is set
- with m.If (pte.g):
- m.d.sync += global_mapping.eq(1)
-
- m.next = "IDLE"
-
- # -------------
- # Invalid PTE
- # -------------
- # If pte.v = 0, or if pte.r = 0 and pte.w = 1,
- # stop and raise a page-fault exception.
- with m.If (pte_inv):
- m.next = "PROPAGATE_ERROR"
-
- # -----------
- # Valid PTE
- # -----------
-
- # it is a valid PTE
- # if pte.r = 1 or pte.x = 1 it is a valid PTE
- with m.Elif (pte_rx):
- # Valid translation found (either 1G, 2M or 4K)
- with m.If(is_instr_ptw):
- # ------------
- # Update ITLB
- # ------------
- # If page not executable, we can directly raise error.
- # This doesn't put a useless entry into the TLB.
- # The same idea applies to the access flag since we let
- # the access flag be managed by SW.
- with m.If (pte_exe):
- m.next = "IDLE"
- with m.Else():
- m.d.comb += self.itlb_update_o.valid.eq(1)
-
- with m.Else():
- # ------------
- # Update DTLB
- # ------------
- # Check if the access flag has been set, otherwise
- # throw page-fault and let software handle those bits.
- # If page not readable (there are no write-only pages)
- # directly raise an error. This doesn't put a useless
- # entry into the TLB.
- with m.If(pte_a):
- m.d.comb += self.dtlb_update_o.valid.eq(1)
- with m.Else():
- m.next = "PROPAGATE_ERROR"
- # Request is a store: perform additional checks
- # If the request was a store and the page not
- # write-able, raise an error
- # the same applies if the dirty flag is not set
- with m.If (st_wd):
- m.d.comb += self.dtlb_update_o.valid.eq(0)
- m.next = "PROPAGATE_ERROR"
-
- # check if the ppn is correctly aligned: Case (6)
- with m.If(l1err | l2err):
- m.next = "PROPAGATE_ERROR"
- m.d.comb += [self.dtlb_update_o.valid.eq(0),
- self.itlb_update_o.valid.eq(0)]
-
- # this is a pointer to the next TLB level
- with m.Else():
- # pointer to next level of page table
- with m.If (ptw_lvl1):
- # we are in the second level now
- pptr = Cat(Const(0, 3), self.dtlb_vaddr_i[21:30], pte.ppn)
- m.d.sync += [ptw_pptr.eq(pptr),
- ptw_lvl.eq(LVL2)
- ]
- with m.If(ptw_lvl2):
- # here we received a pointer to the third level
- pptr = Cat(Const(0, 3), self.dtlb_vaddr_i[12:21], pte.ppn)
- m.d.sync += [ptw_pptr.eq(pptr),
- ptw_lvl.eq(LVL3)
- ]
- self.set_grant_state(m)
-
- with m.If (ptw_lvl3):
- # Should already be the last level
- # page table => Error
- m.d.sync += ptw_lvl.eq(LVL3)
- m.next = "PROPAGATE_ERROR"
-
-
-if __name__ == '__main__':
- ptw = PTW()
- vl = rtlil.convert(ptw, ports=ptw.ports())
- with open("test_ptw.il", "w") as f:
- f.write(vl)
+++ /dev/null
-"""
-# Copyright 2018 ETH Zurich and University of Bologna.
-# Copyright and related rights are licensed under the Solderpad Hardware
-# License, Version 0.51 (the "License"); you may not use this file except in
-# compliance with the License. You may obtain a copy of the License at
-# http:#solderpad.org/licenses/SHL-0.51. Unless required by applicable law
-# or agreed to in writing, software, hardware and materials distributed under
-# this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
-# CONDITIONS OF ANY KIND, either express or implied. See the License for the
-# specific language governing permissions and limitations under the License.
-#
-# Author: David Schaffenrath, TU Graz
-# Author: Florian Zaruba, ETH Zurich
-# Date: 21.4.2017
-# Description: Translation Lookaside Buffer, SV39
-# fully set-associative
-
-Implementation in c++:
-https://raw.githubusercontent.com/Tony-Hu/TreePLRU/master/TreePLRU.cpp
-
-Text description:
-https://people.cs.clemson.edu/~mark/464/p_lru.txt
-
-Online simulator:
-http://www.ntu.edu.sg/home/smitha/ParaCache/Paracache/vm.html
-"""
-from math import log2
-from nmigen import Signal, Module, Cat, Const, Array
-from nmigen.cli import verilog, rtlil
-from nmigen.lib.coding import Encoder
-
-from ptw import TLBUpdate, PTE, ASID_WIDTH
-from plru import PLRU
-from tlb_content import TLBContent
-
-TLB_ENTRIES = 8
-
-class TLB:
- def __init__(self, tlb_entries=8, asid_width=8):
- self.tlb_entries = tlb_entries
- self.asid_width = asid_width
-
- self.flush_i = Signal() # Flush signal
- # Lookup signals
- self.lu_access_i = Signal()
- self.lu_asid_i = Signal(self.asid_width)
- self.lu_vaddr_i = Signal(64)
- self.lu_content_o = PTE()
- self.lu_is_2M_o = Signal()
- self.lu_is_1G_o = Signal()
- self.lu_hit_o = Signal()
- # Update TLB
- self.pte_width = len(self.lu_content_o.flatten())
- self.update_i = TLBUpdate(asid_width)
-
- def elaborate(self, platform):
- m = Module()
-
- vpn2 = Signal(9)
- vpn1 = Signal(9)
- vpn0 = Signal(9)
-
- #-------------
- # Translation
- #-------------
-
- # SV39 defines three levels of page tables
- m.d.comb += [ vpn0.eq(self.lu_vaddr_i[12:21]),
- vpn1.eq(self.lu_vaddr_i[21:30]),
- vpn2.eq(self.lu_vaddr_i[30:39]),
- ]
-
- tc = []
- for i in range(self.tlb_entries):
- tlc = TLBContent(self.pte_width, self.asid_width)
- setattr(m.submodules, "tc%d" % i, tlc)
- tc.append(tlc)
- # connect inputs
- tlc.update_i = self.update_i # saves a lot of graphviz links
- m.d.comb += [tlc.vpn0.eq(vpn0),
- tlc.vpn1.eq(vpn1),
- tlc.vpn2.eq(vpn2),
- tlc.flush_i.eq(self.flush_i),
- #tlc.update_i.eq(self.update_i),
- tlc.lu_asid_i.eq(self.lu_asid_i)]
- tc = Array(tc)
-
- #--------------
- # Select hit
- #--------------
-
- # use Encoder to select hit index
- # XXX TODO: assert that there's only one valid entry (one lu_hit)
- hitsel = Encoder(self.tlb_entries)
- m.submodules.hitsel = hitsel
-
- hits = []
- for i in range(self.tlb_entries):
- hits.append(tc[i].lu_hit_o)
- m.d.comb += hitsel.i.eq(Cat(*hits)) # (goes into plru as well)
- idx = hitsel.o
-
- active = Signal(reset_less=True)
- m.d.comb += active.eq(~hitsel.n)
- with m.If(active):
- # active hit, send selected as output
- m.d.comb += [ self.lu_is_1G_o.eq(tc[idx].lu_is_1G_o),
- self.lu_is_2M_o.eq(tc[idx].lu_is_2M_o),
- self.lu_hit_o.eq(1),
- self.lu_content_o.flatten().eq(tc[idx].lu_content_o),
- ]
-
- #--------------
- # PLRU.
- #--------------
-
- p = PLRU(self.tlb_entries)
- plru_tree = Signal(p.TLBSZ)
- m.submodules.plru = p
-
- # connect PLRU inputs/outputs
- # XXX TODO: assert that there's only one valid entry (one replace_en)
- en = []
- for i in range(self.tlb_entries):
- en.append(tc[i].replace_en_i)
- m.d.comb += [Cat(*en).eq(p.replace_en_o), # output from PLRU into tags
- p.lu_hit.eq(hitsel.i),
- p.lu_access_i.eq(self.lu_access_i),
- p.plru_tree.eq(plru_tree)]
- m.d.sync += plru_tree.eq(p.plru_tree_o)
-
- #--------------
- # Sanity checks
- #--------------
-
- assert (self.tlb_entries % 2 == 0) and (self.tlb_entries > 1), \
- "TLB size must be a multiple of 2 and greater than 1"
- assert (self.asid_width >= 1), \
- "ASID width must be at least 1"
-
- return m
-
- """
- # Just for checking
- function int countSetBits(logic[self.tlb_entries-1:0] vector);
- automatic int count = 0;
- foreach (vector[idx]) begin
- count += vector[idx];
- end
- return count;
- endfunction
-
- assert property (@(posedge clk_i)(countSetBits(lu_hit) <= 1))
- else $error("More then one hit in TLB!"); $stop(); end
- assert property (@(posedge clk_i)(countSetBits(replace_en) <= 1))
- else $error("More then one TLB entry selected for next replace!");
- """
-
- def ports(self):
- return [self.flush_i, self.lu_access_i,
- self.lu_asid_i, self.lu_vaddr_i,
- self.lu_is_2M_o, self.lu_is_1G_o, self.lu_hit_o,
- ] + self.lu_content_o.ports() + self.update_i.ports()
-
-if __name__ == '__main__':
- tlb = TLB()
- vl = rtlil.convert(tlb, ports=tlb.ports())
- with open("test_tlb.il", "w") as f:
- f.write(vl)
-
+++ /dev/null
-from nmigen import Signal, Module, Cat, Const
-
-from ptw import TLBUpdate, PTE
-
-class TLBEntry:
- def __init__(self, asid_width):
- self.asid = Signal(asid_width)
- # SV39 defines three levels of page tables
- self.vpn0 = Signal(9)
- self.vpn1 = Signal(9)
- self.vpn2 = Signal(9)
- self.is_2M = Signal()
- self.is_1G = Signal()
- self.valid = Signal()
-
- def flatten(self):
- return Cat(*self.ports())
-
- def eq(self, x):
- return self.flatten().eq(x.flatten())
-
- def ports(self):
- return [self.asid, self.vpn0, self.vpn1, self.vpn2,
- self.is_2M, self.is_1G, self.valid]
-
-class TLBContent:
- def __init__(self, pte_width, asid_width):
- self.asid_width = asid_width
- self.pte_width = pte_width
- self.flush_i = Signal() # Flush signal
- # Update TLB
- self.update_i = TLBUpdate(asid_width)
- self.vpn2 = Signal(9)
- self.vpn1 = Signal(9)
- self.vpn0 = Signal(9)
- self.replace_en_i = Signal() # replace the following entry,
- # set by replacement strategy
- # Lookup signals
- self.lu_asid_i = Signal(asid_width)
- self.lu_content_o = Signal(pte_width)
- self.lu_is_2M_o = Signal()
- self.lu_is_1G_o = Signal()
- self.lu_hit_o = Signal()
-
- def elaborate(self, platform):
- m = Module()
-
- tags = TLBEntry(self.asid_width)
- content = Signal(self.pte_width)
-
- m.d.comb += [self.lu_hit_o.eq(0),
- self.lu_is_2M_o.eq(0),
- self.lu_is_1G_o.eq(0)]
-
- # temporaries for 1st level match
- asid_ok = Signal(reset_less=True)
- vpn2_ok = Signal(reset_less=True)
- tags_ok = Signal(reset_less=True)
- vpn2_hit = Signal(reset_less=True)
- m.d.comb += [tags_ok.eq(tags.valid),
- asid_ok.eq(tags.asid == self.lu_asid_i),
- vpn2_ok.eq(tags.vpn2 == self.vpn2),
- vpn2_hit.eq(tags_ok & asid_ok & vpn2_ok)]
- # temporaries for 2nd level match
- vpn1_ok = Signal(reset_less=True)
- tags_2M = Signal(reset_less=True)
- vpn0_ok = Signal(reset_less=True)
- vpn0_or_2M = Signal(reset_less=True)
- m.d.comb += [vpn1_ok.eq(self.vpn1 == tags.vpn1),
- tags_2M.eq(tags.is_2M),
- vpn0_ok.eq(self.vpn0 == tags.vpn0),
- vpn0_or_2M.eq(tags_2M | vpn0_ok)]
- # first level match, this may be a giga page,
- # check the ASID flags as well
- with m.If(vpn2_hit):
- # second level
- with m.If (tags.is_1G):
- m.d.comb += [ self.lu_content_o.eq(content),
- self.lu_is_1G_o.eq(1),
- self.lu_hit_o.eq(1),
- ]
- # not a giga page hit so check further
- with m.Elif(vpn1_ok):
- # this could be a 2 mega page hit or a 4 kB hit
- # output accordingly
- with m.If(vpn0_or_2M):
- m.d.comb += [ self.lu_content_o.eq(content),
- self.lu_is_2M_o.eq(tags.is_2M),
- self.lu_hit_o.eq(1),
- ]
- # ------------------
- # Update or Flush
- # ------------------
-
- # temporaries
- replace_valid = Signal(reset_less=True)
- m.d.comb += replace_valid.eq(self.update_i.valid & self.replace_en_i)
-
- # flush
- with m.If (self.flush_i):
- # invalidate (flush) conditions: all if zero or just this ASID
- with m.If (self.lu_asid_i == Const(0, self.asid_width) |
- (self.lu_asid_i == tags.asid)):
- m.d.sync += tags.valid.eq(0)
-
- # normal replacement
- with m.Elif(replace_valid):
- m.d.sync += [ # update tag array
- tags.asid.eq(self.update_i.asid),
- tags.vpn2.eq(self.update_i.vpn[18:27]),
- tags.vpn1.eq(self.update_i.vpn[9:18]),
- tags.vpn0.eq(self.update_i.vpn[0:9]),
- tags.is_1G.eq(self.update_i.is_1G),
- tags.is_2M.eq(self.update_i.is_2M),
- tags.valid.eq(1),
- # and content as well
- content.eq(self.update_i.content.flatten())
- ]
- return m
-
- def ports(self):
- return [self.flush_i,
- self.lu_asid_i,
- self.lu_is_2M_o, self.lu_is_1G_o, self.lu_hit_o,
- ] + self.update_i.content.ports() + self.update_i.ports()
--- /dev/null
+"""
+# Copyright 2018 ETH Zurich and University of Bologna.
+# Copyright and related rights are licensed under the Solderpad Hardware
+# License, Version 0.51 (the "License"); you may not use this file except in
+# compliance with the License. You may obtain a copy of the License at
+# http:#solderpad.org/licenses/SHL-0.51. Unless required by applicable law
+# or agreed to in writing, software, hardware and materials distributed under
+# this License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR
+# CONDITIONS OF ANY KIND, either express or implied. See the License for the
+# specific language governing permissions and limitations under the License.
+#
+# Author: David Schaffenrath, TU Graz
+# Author: Florian Zaruba, ETH Zurich
+# Date: 21.4.2017
+# Description: Translation Lookaside Buffer, SV39
+# fully set-associative
+
+Implementation in c++:
+https://raw.githubusercontent.com/Tony-Hu/TreePLRU/master/TreePLRU.cpp
+
+Text description:
+https://people.cs.clemson.edu/~mark/464/p_lru.txt
+
+Online simulator:
+http://www.ntu.edu.sg/home/smitha/ParaCache/Paracache/vm.html
+"""
+from math import log2
+from nmigen import Signal, Module, Cat, Const, Array
+from nmigen.cli import verilog, rtlil
+from nmigen.lib.coding import Encoder
+
+from ptw import TLBUpdate, PTE, ASID_WIDTH
+from plru import PLRU
+from tlb_content import TLBContent
+
+TLB_ENTRIES = 8
+
+class TLB:
+ def __init__(self, tlb_entries=8, asid_width=8):
+ self.tlb_entries = tlb_entries
+ self.asid_width = asid_width
+
+ self.flush_i = Signal() # Flush signal
+ # Lookup signals
+ self.lu_access_i = Signal()
+ self.lu_asid_i = Signal(self.asid_width)
+ self.lu_vaddr_i = Signal(64)
+ self.lu_content_o = PTE()
+ self.lu_is_2M_o = Signal()
+ self.lu_is_1G_o = Signal()
+ self.lu_hit_o = Signal()
+ # Update TLB
+ self.pte_width = len(self.lu_content_o.flatten())
+ self.update_i = TLBUpdate(asid_width)
+
+ def elaborate(self, platform):
+ m = Module()
+
+ vpn2 = Signal(9)
+ vpn1 = Signal(9)
+ vpn0 = Signal(9)
+
+ #-------------
+ # Translation
+ #-------------
+
+ # SV39 defines three levels of page tables
+ m.d.comb += [ vpn0.eq(self.lu_vaddr_i[12:21]),
+ vpn1.eq(self.lu_vaddr_i[21:30]),
+ vpn2.eq(self.lu_vaddr_i[30:39]),
+ ]
+
+ tc = []
+ for i in range(self.tlb_entries):
+ tlc = TLBContent(self.pte_width, self.asid_width)
+ setattr(m.submodules, "tc%d" % i, tlc)
+ tc.append(tlc)
+ # connect inputs
+ tlc.update_i = self.update_i # saves a lot of graphviz links
+ m.d.comb += [tlc.vpn0.eq(vpn0),
+ tlc.vpn1.eq(vpn1),
+ tlc.vpn2.eq(vpn2),
+ tlc.flush_i.eq(self.flush_i),
+ #tlc.update_i.eq(self.update_i),
+ tlc.lu_asid_i.eq(self.lu_asid_i)]
+ tc = Array(tc)
+
+ #--------------
+ # Select hit
+ #--------------
+
+ # use Encoder to select hit index
+ # XXX TODO: assert that there's only one valid entry (one lu_hit)
+ hitsel = Encoder(self.tlb_entries)
+ m.submodules.hitsel = hitsel
+
+ hits = []
+ for i in range(self.tlb_entries):
+ hits.append(tc[i].lu_hit_o)
+ m.d.comb += hitsel.i.eq(Cat(*hits)) # (goes into plru as well)
+ idx = hitsel.o
+
+ active = Signal(reset_less=True)
+ m.d.comb += active.eq(~hitsel.n)
+ with m.If(active):
+ # active hit, send selected as output
+ m.d.comb += [ self.lu_is_1G_o.eq(tc[idx].lu_is_1G_o),
+ self.lu_is_2M_o.eq(tc[idx].lu_is_2M_o),
+ self.lu_hit_o.eq(1),
+ self.lu_content_o.flatten().eq(tc[idx].lu_content_o),
+ ]
+
+ #--------------
+ # PLRU.
+ #--------------
+
+ p = PLRU(self.tlb_entries)
+ plru_tree = Signal(p.TLBSZ)
+ m.submodules.plru = p
+
+ # connect PLRU inputs/outputs
+ # XXX TODO: assert that there's only one valid entry (one replace_en)
+ en = []
+ for i in range(self.tlb_entries):
+ en.append(tc[i].replace_en_i)
+ m.d.comb += [Cat(*en).eq(p.replace_en_o), # output from PLRU into tags
+ p.lu_hit.eq(hitsel.i),
+ p.lu_access_i.eq(self.lu_access_i),
+ p.plru_tree.eq(plru_tree)]
+ m.d.sync += plru_tree.eq(p.plru_tree_o)
+
+ #--------------
+ # Sanity checks
+ #--------------
+
+ assert (self.tlb_entries % 2 == 0) and (self.tlb_entries > 1), \
+ "TLB size must be a multiple of 2 and greater than 1"
+ assert (self.asid_width >= 1), \
+ "ASID width must be at least 1"
+
+ return m
+
+ """
+ # Just for checking
+ function int countSetBits(logic[self.tlb_entries-1:0] vector);
+ automatic int count = 0;
+ foreach (vector[idx]) begin
+ count += vector[idx];
+ end
+ return count;
+ endfunction
+
+ assert property (@(posedge clk_i)(countSetBits(lu_hit) <= 1))
+ else $error("More then one hit in TLB!"); $stop(); end
+ assert property (@(posedge clk_i)(countSetBits(replace_en) <= 1))
+ else $error("More then one TLB entry selected for next replace!");
+ """
+
+ def ports(self):
+ return [self.flush_i, self.lu_access_i,
+ self.lu_asid_i, self.lu_vaddr_i,
+ self.lu_is_2M_o, self.lu_is_1G_o, self.lu_hit_o,
+ ] + self.lu_content_o.ports() + self.update_i.ports()
+
+if __name__ == '__main__':
+ tlb = TLB()
+ vl = rtlil.convert(tlb, ports=tlb.ports())
+ with open("test_tlb.il", "w") as f:
+ f.write(vl)
+
--- /dev/null
+from nmigen import Signal, Module, Cat, Const
+
+from ptw import TLBUpdate, PTE
+
+class TLBEntry:
+ def __init__(self, asid_width):
+ self.asid = Signal(asid_width)
+ # SV39 defines three levels of page tables
+ self.vpn0 = Signal(9)
+ self.vpn1 = Signal(9)
+ self.vpn2 = Signal(9)
+ self.is_2M = Signal()
+ self.is_1G = Signal()
+ self.valid = Signal()
+
+ def flatten(self):
+ return Cat(*self.ports())
+
+ def eq(self, x):
+ return self.flatten().eq(x.flatten())
+
+ def ports(self):
+ return [self.asid, self.vpn0, self.vpn1, self.vpn2,
+ self.is_2M, self.is_1G, self.valid]
+
+class TLBContent:
+ def __init__(self, pte_width, asid_width):
+ self.asid_width = asid_width
+ self.pte_width = pte_width
+ self.flush_i = Signal() # Flush signal
+ # Update TLB
+ self.update_i = TLBUpdate(asid_width)
+ self.vpn2 = Signal(9)
+ self.vpn1 = Signal(9)
+ self.vpn0 = Signal(9)
+ self.replace_en_i = Signal() # replace the following entry,
+ # set by replacement strategy
+ # Lookup signals
+ self.lu_asid_i = Signal(asid_width)
+ self.lu_content_o = Signal(pte_width)
+ self.lu_is_2M_o = Signal()
+ self.lu_is_1G_o = Signal()
+ self.lu_hit_o = Signal()
+
+ def elaborate(self, platform):
+ m = Module()
+
+ tags = TLBEntry(self.asid_width)
+ content = Signal(self.pte_width)
+
+ m.d.comb += [self.lu_hit_o.eq(0),
+ self.lu_is_2M_o.eq(0),
+ self.lu_is_1G_o.eq(0)]
+
+ # temporaries for 1st level match
+ asid_ok = Signal(reset_less=True)
+ vpn2_ok = Signal(reset_less=True)
+ tags_ok = Signal(reset_less=True)
+ vpn2_hit = Signal(reset_less=True)
+ m.d.comb += [tags_ok.eq(tags.valid),
+ asid_ok.eq(tags.asid == self.lu_asid_i),
+ vpn2_ok.eq(tags.vpn2 == self.vpn2),
+ vpn2_hit.eq(tags_ok & asid_ok & vpn2_ok)]
+ # temporaries for 2nd level match
+ vpn1_ok = Signal(reset_less=True)
+ tags_2M = Signal(reset_less=True)
+ vpn0_ok = Signal(reset_less=True)
+ vpn0_or_2M = Signal(reset_less=True)
+ m.d.comb += [vpn1_ok.eq(self.vpn1 == tags.vpn1),
+ tags_2M.eq(tags.is_2M),
+ vpn0_ok.eq(self.vpn0 == tags.vpn0),
+ vpn0_or_2M.eq(tags_2M | vpn0_ok)]
+ # first level match, this may be a giga page,
+ # check the ASID flags as well
+ with m.If(vpn2_hit):
+ # second level
+ with m.If (tags.is_1G):
+ m.d.comb += [ self.lu_content_o.eq(content),
+ self.lu_is_1G_o.eq(1),
+ self.lu_hit_o.eq(1),
+ ]
+ # not a giga page hit so check further
+ with m.Elif(vpn1_ok):
+ # this could be a 2 mega page hit or a 4 kB hit
+ # output accordingly
+ with m.If(vpn0_or_2M):
+ m.d.comb += [ self.lu_content_o.eq(content),
+ self.lu_is_2M_o.eq(tags.is_2M),
+ self.lu_hit_o.eq(1),
+ ]
+ # ------------------
+ # Update or Flush
+ # ------------------
+
+ # temporaries
+ replace_valid = Signal(reset_less=True)
+ m.d.comb += replace_valid.eq(self.update_i.valid & self.replace_en_i)
+
+ # flush
+ with m.If (self.flush_i):
+ # invalidate (flush) conditions: all if zero or just this ASID
+ with m.If (self.lu_asid_i == Const(0, self.asid_width) |
+ (self.lu_asid_i == tags.asid)):
+ m.d.sync += tags.valid.eq(0)
+
+ # normal replacement
+ with m.Elif(replace_valid):
+ m.d.sync += [ # update tag array
+ tags.asid.eq(self.update_i.asid),
+ tags.vpn2.eq(self.update_i.vpn[18:27]),
+ tags.vpn1.eq(self.update_i.vpn[9:18]),
+ tags.vpn0.eq(self.update_i.vpn[0:9]),
+ tags.is_1G.eq(self.update_i.is_1G),
+ tags.is_2M.eq(self.update_i.is_2M),
+ tags.valid.eq(1),
+ # and content as well
+ content.eq(self.update_i.content.flatten())
+ ]
+ return m
+
+ def ports(self):
+ return [self.flush_i,
+ self.lu_asid_i,
+ self.lu_is_2M_o, self.lu_is_1G_o, self.lu_hit_o,
+ ] + self.update_i.content.ports() + self.update_i.ports()
-import sys
-sys.path.append("../src")
-sys.path.append("../../TestUtil")
-
from nmigen.compat.sim import run_simulation
-from SetAssociativeCache import SetAssociativeCache
+from TLB.SetAssociativeCache import SetAssociativeCache
-from test_helper import assert_eq, assert_ne, assert_op
+from TestUtil.test_helper import assert_eq, assert_ne, assert_op
def set_sac(dut, e, c, s, t, d):
yield dut.enable.eq(e)
yield dut.data_i.eq(d)
yield
-def testbench(dut):
+def tbench(dut):
enable = 1
command = 2
cset = 1
yield from set_sac(dut, enable, command, cset, tag, data)
yield
-if __name__ == "__main__":
+def test_assoc_cache():
dut = SetAssociativeCache(4, 4, 4, 4)
- run_simulation(dut, testbench(dut), vcd_name="Waveforms/test_set_associative_cache.vcd")
+ run_simulation(dut, tbench(dut), vcd_name="Waveforms/test_set_associative_cache.vcd")
print("Set Associative Cache Unit Test Success")
+
+if __name__ == "__main__":
+ test_assoc_cache()
projects / soc.git / commitdiff