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riscv_pmp_regs.sail
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/*=======================================================================================*/
/* This Sail RISC-V architecture model, comprising all files and */
/* directories except where otherwise noted is subject the BSD */
/* two-clause license in the LICENSE file. */
/* */
/* SPDX-License-Identifier: BSD-2-Clause */
/*=======================================================================================*/
/* PMP configuration entries */
enum PmpAddrMatchType = {OFF, TOR, NA4, NAPOT}
val pmpAddrMatchType_of_bits : bits(2) -> PmpAddrMatchType
function pmpAddrMatchType_of_bits(bs) = {
match bs {
0b00 => OFF,
0b01 => TOR,
0b10 => NA4,
0b11 => NAPOT
}
}
val pmpAddrMatchType_to_bits : PmpAddrMatchType -> bits(2)
function pmpAddrMatchType_to_bits(bs) = {
match bs {
OFF => 0b00,
TOR => 0b01,
NA4 => 0b10,
NAPOT => 0b11
}
}
bitfield Pmpcfg_ent : bits(8) = {
L : 7, /* locking */
A : 4 .. 3, /* address match type, encoded as above */
/* permissions */
X : 2, /* execute */
W : 1, /* write */
R : 0 /* read */
}
register pmpcfg_n : vector(64, Pmpcfg_ent)
register pmpaddr_n : vector(64, xlenbits)
/* Packing and unpacking pmpcfg regs for xlen-width accesses */
function pmpReadCfgReg(n : range(0, 15)) -> xlenbits = {
if xlen == 32
then {
pmpcfg_n[n*4 + 3].bits @
pmpcfg_n[n*4 + 2].bits @
pmpcfg_n[n*4 + 1].bits @
pmpcfg_n[n*4 + 0].bits
}
else {
assert(n % 2 == 0, "Unexpected pmp config reg read");
pmpcfg_n[n*4 + 7].bits @
pmpcfg_n[n*4 + 6].bits @
pmpcfg_n[n*4 + 5].bits @
pmpcfg_n[n*4 + 4].bits @
pmpcfg_n[n*4 + 3].bits @
pmpcfg_n[n*4 + 2].bits @
pmpcfg_n[n*4 + 1].bits @
pmpcfg_n[n*4 + 0].bits
}
}
function pmpReadAddrReg(n : range(0, 63)) -> xlenbits = {
let G = sys_pmp_grain();
let match_type = pmpcfg_n[n][A];
let addr = pmpaddr_n[n];
match match_type[1] {
bitone if G >= 2 => {
// [G-2..0] read as all ones to form mask, therefore we need G-1 bits.
let mask : xlenbits = zero_extend(ones(min(G - 1, xlen)));
addr | mask
},
bitzero if G >= 1 => {
// [G-1..0] read as all zeros to form mask, therefore we need G bits.
let mask : xlenbits = zero_extend(ones(min(G , xlen)));
addr & ~(mask)
},
_ => addr,
}
}
/* Helpers to handle locked entries */
function pmpLocked(cfg: Pmpcfg_ent) -> bool =
cfg[L] == 0b1
function pmpTORLocked(cfg: Pmpcfg_ent) -> bool =
(cfg[L] == 0b1) & (pmpAddrMatchType_of_bits(cfg[A]) == TOR)
function pmpWriteCfg(n: range(0, 63), cfg: Pmpcfg_ent, v: bits(8)) -> Pmpcfg_ent =
if pmpLocked(cfg) then cfg
else {
// Bits 5 and 6 are zero.
let cfg = Mk_Pmpcfg_ent(v & 0x9f);
// "The R, W, and X fields form a collective WARL field for which the combinations with R=0 and W=1 are reserved."
// In this implementation if R=0 and W=1 then R, W and X are all set to 0.
// This is the least risky option from a security perspective.
let cfg = if cfg[W] == 0b1 & cfg[R] == 0b0 then [cfg with X = 0b0, W = 0b0, R = 0b0] else cfg;
// "When G >= 1, the NA4 mode is not selectable."
// In this implementation we set it to OFF if NA4 is selected.
// This is the least risky option from a security perspective.
let cfg = if sys_pmp_grain() >= 1 & pmpAddrMatchType_of_bits(cfg[A]) == NA4
then [cfg with A = pmpAddrMatchType_to_bits(OFF)]
else cfg;
cfg
}
function pmpWriteCfgReg(n : range(0, 15), v : xlenbits) -> unit = {
if xlen == 32
then {
foreach (i from 0 to 3) {
let idx = n*4 + i;
pmpcfg_n[idx] = pmpWriteCfg(idx, pmpcfg_n[idx], v[8*i+7 .. 8*i]);
}
}
else {
assert(n % 2 == 0, "Unexpected pmp config reg write");
foreach (i from 0 to 7) {
let idx = n*4 + i;
pmpcfg_n[idx] = pmpWriteCfg(idx, pmpcfg_n[idx], v[8*i+7 .. 8*i]);
}
}
}
function pmpWriteAddr(locked: bool, tor_locked: bool, reg: xlenbits, v: xlenbits) -> xlenbits =
if xlen == 32
then { if (locked | tor_locked) then reg else v }
else { if (locked | tor_locked) then reg else zero_extend(v[53..0]) }
function pmpWriteAddrReg(n : range(0, 63), v : xlenbits) -> unit = {
pmpaddr_n[n] = pmpWriteAddr(
pmpLocked(pmpcfg_n[n]),
if n + 1 < 64 then pmpTORLocked(pmpcfg_n[n + 1]) else false,
pmpaddr_n[n],
v,
);
}
/* PMP CSRs */
mapping clause csr_name_map = 0x3A0 <-> "pmpcfg0"
mapping clause csr_name_map = 0x3A1 <-> "pmpcfg1"
mapping clause csr_name_map = 0x3A2 <-> "pmpcfg2"
mapping clause csr_name_map = 0x3A3 <-> "pmpcfg3"
mapping clause csr_name_map = 0x3A4 <-> "pmpcfg4"
mapping clause csr_name_map = 0x3A5 <-> "pmpcfg5"
mapping clause csr_name_map = 0x3A6 <-> "pmpcfg6"
mapping clause csr_name_map = 0x3A7 <-> "pmpcfg7"
mapping clause csr_name_map = 0x3A8 <-> "pmpcfg8"
mapping clause csr_name_map = 0x3A9 <-> "pmpcfg9"
mapping clause csr_name_map = 0x3AA <-> "pmpcfg10"
mapping clause csr_name_map = 0x3AB <-> "pmpcfg11"
mapping clause csr_name_map = 0x3AC <-> "pmpcfg12"
mapping clause csr_name_map = 0x3AD <-> "pmpcfg13"
mapping clause csr_name_map = 0x3AE <-> "pmpcfg14"
mapping clause csr_name_map = 0x3AF <-> "pmpcfg15"
mapping clause csr_name_map = 0x3B0 <-> "pmpaddr0"
mapping clause csr_name_map = 0x3B1 <-> "pmpaddr1"
mapping clause csr_name_map = 0x3B2 <-> "pmpaddr2"
mapping clause csr_name_map = 0x3B3 <-> "pmpaddr3"
mapping clause csr_name_map = 0x3B4 <-> "pmpaddr4"
mapping clause csr_name_map = 0x3B5 <-> "pmpaddr5"
mapping clause csr_name_map = 0x3B6 <-> "pmpaddr6"
mapping clause csr_name_map = 0x3B7 <-> "pmpaddr7"
mapping clause csr_name_map = 0x3B8 <-> "pmpaddr8"
mapping clause csr_name_map = 0x3B9 <-> "pmpaddr9"
mapping clause csr_name_map = 0x3BA <-> "pmpaddr10"
mapping clause csr_name_map = 0x3BB <-> "pmpaddr11"
mapping clause csr_name_map = 0x3BC <-> "pmpaddr12"
mapping clause csr_name_map = 0x3BD <-> "pmpaddr13"
mapping clause csr_name_map = 0x3BE <-> "pmpaddr14"
mapping clause csr_name_map = 0x3BF <-> "pmpaddr15"
mapping clause csr_name_map = 0x3C0 <-> "pmpaddr16"
mapping clause csr_name_map = 0x3C1 <-> "pmpaddr17"
mapping clause csr_name_map = 0x3C2 <-> "pmpaddr18"
mapping clause csr_name_map = 0x3C3 <-> "pmpaddr19"
mapping clause csr_name_map = 0x3C4 <-> "pmpaddr20"
mapping clause csr_name_map = 0x3C5 <-> "pmpaddr21"
mapping clause csr_name_map = 0x3C6 <-> "pmpaddr22"
mapping clause csr_name_map = 0x3C7 <-> "pmpaddr23"
mapping clause csr_name_map = 0x3C8 <-> "pmpaddr24"
mapping clause csr_name_map = 0x3C9 <-> "pmpaddr25"
mapping clause csr_name_map = 0x3CA <-> "pmpaddr26"
mapping clause csr_name_map = 0x3CB <-> "pmpaddr27"
mapping clause csr_name_map = 0x3CC <-> "pmpaddr28"
mapping clause csr_name_map = 0x3CD <-> "pmpaddr29"
mapping clause csr_name_map = 0x3CE <-> "pmpaddr30"
mapping clause csr_name_map = 0x3CF <-> "pmpaddr31"
mapping clause csr_name_map = 0x3D0 <-> "pmpaddr32"
mapping clause csr_name_map = 0x3D1 <-> "pmpaddr33"
mapping clause csr_name_map = 0x3D2 <-> "pmpaddr34"
mapping clause csr_name_map = 0x3D3 <-> "pmpaddr35"
mapping clause csr_name_map = 0x3D4 <-> "pmpaddr36"
mapping clause csr_name_map = 0x3D5 <-> "pmpaddr37"
mapping clause csr_name_map = 0x3D6 <-> "pmpaddr38"
mapping clause csr_name_map = 0x3D7 <-> "pmpaddr39"
mapping clause csr_name_map = 0x3D8 <-> "pmpaddr40"
mapping clause csr_name_map = 0x3D9 <-> "pmpaddr41"
mapping clause csr_name_map = 0x3DA <-> "pmpaddr42"
mapping clause csr_name_map = 0x3DB <-> "pmpaddr43"
mapping clause csr_name_map = 0x3DC <-> "pmpaddr44"
mapping clause csr_name_map = 0x3DD <-> "pmpaddr45"
mapping clause csr_name_map = 0x3DE <-> "pmpaddr46"
mapping clause csr_name_map = 0x3DF <-> "pmpaddr47"
mapping clause csr_name_map = 0x3E0 <-> "pmpaddr48"
mapping clause csr_name_map = 0x3E1 <-> "pmpaddr49"
mapping clause csr_name_map = 0x3E2 <-> "pmpaddr50"
mapping clause csr_name_map = 0x3E3 <-> "pmpaddr51"
mapping clause csr_name_map = 0x3E4 <-> "pmpaddr52"
mapping clause csr_name_map = 0x3E5 <-> "pmpaddr53"
mapping clause csr_name_map = 0x3E6 <-> "pmpaddr54"
mapping clause csr_name_map = 0x3E7 <-> "pmpaddr55"
mapping clause csr_name_map = 0x3E8 <-> "pmpaddr56"
mapping clause csr_name_map = 0x3E9 <-> "pmpaddr57"
mapping clause csr_name_map = 0x3EA <-> "pmpaddr58"
mapping clause csr_name_map = 0x3EB <-> "pmpaddr59"
mapping clause csr_name_map = 0x3EC <-> "pmpaddr60"
mapping clause csr_name_map = 0x3ED <-> "pmpaddr61"
mapping clause csr_name_map = 0x3EE <-> "pmpaddr62"
mapping clause csr_name_map = 0x3EF <-> "pmpaddr63"
// pmpcfgN
function clause is_CSR_defined(0x3A) @ idx : bits(4) = sys_pmp_count() > unsigned(idx) & (idx[0] == bitzero | xlen == 32)
function clause read_CSR(0x3A @ idx : bits(4) if idx[0] == bitzero | xlen == 32) = pmpReadCfgReg(unsigned(idx))
function clause write_CSR((0x3A @ idx : bits(4), value) if idx[0] == bitzero | xlen == 32) = {
let idx = unsigned(idx);
pmpWriteCfgReg(idx, value);
pmpReadCfgReg(idx)
}
// pmpaddrN. Unfortunately the PMP index does not nicely align with the CSR index bits.
function clause is_CSR_defined(0x3B) @ idx : bits(4) = sys_pmp_count() > unsigned(0b00 @ idx)
function clause is_CSR_defined(0x3C) @ idx : bits(4) = sys_pmp_count() > unsigned(0b01 @ idx)
function clause is_CSR_defined(0x3D) @ idx : bits(4) = sys_pmp_count() > unsigned(0b10 @ idx)
function clause is_CSR_defined(0x3E) @ idx : bits(4) = sys_pmp_count() > unsigned(0b11 @ idx)
function clause read_CSR(0x3B @ idx : bits(4)) = pmpReadAddrReg(unsigned(0b00 @ idx))
function clause read_CSR(0x3C @ idx : bits(4)) = pmpReadAddrReg(unsigned(0b01 @ idx))
function clause read_CSR(0x3D @ idx : bits(4)) = pmpReadAddrReg(unsigned(0b10 @ idx))
function clause read_CSR(0x3E @ idx : bits(4)) = pmpReadAddrReg(unsigned(0b11 @ idx))
function clause write_CSR(0x3B @ idx : bits(4), value) = { let idx = unsigned(0b00 @ idx); pmpWriteAddrReg(idx, value); pmpReadAddrReg(idx) }
function clause write_CSR(0x3C @ idx : bits(4), value) = { let idx = unsigned(0b01 @ idx); pmpWriteAddrReg(idx, value); pmpReadAddrReg(idx) }
function clause write_CSR(0x3D @ idx : bits(4), value) = { let idx = unsigned(0b10 @ idx); pmpWriteAddrReg(idx, value); pmpReadAddrReg(idx) }
function clause write_CSR(0x3E @ idx : bits(4), value) = { let idx = unsigned(0b11 @ idx); pmpWriteAddrReg(idx, value); pmpReadAddrReg(idx) }