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/* address ranges */
// TODO: handle PMP grain > 4 (i.e. G > 0).
// TODO: handle the 34-bit paddr32 on RV32
/* [min, max) of the matching range. */
type pmp_addr_range = option((xlenbits, xlenbits))
function pmpAddrRange(cfg: Pmpcfg_ent, pmpaddr: xlenbits, prev_pmpaddr: xlenbits) -> pmp_addr_range = {
match pmpAddrMatchType_of_bits(cfg.A()) {
OFF => None(),
TOR => { Some ((prev_pmpaddr << 2, pmpaddr << 2)) },
NA4 => { // TODO: I find the spec unclear for entries marked NA4 and G = 1.
// (for G >= 2, it is the same as NAPOT). In particular, it affects
// whether pmpaddr[0] is always read as 0.
let lo = pmpaddr << 2;
Some((lo, lo + 4))
},
NAPOT => { let mask = pmpaddr ^ (pmpaddr + 1); // generate 1s in signifying bits
let lo = pmpaddr & (~ (mask));
let len = mask + 1;
Some((lo << 2, (lo + len) << 2))
}
}
}
/* permission checks */
val pmpCheckRWX: (Pmpcfg_ent, AccessType(ext_access_type)) -> bool
function pmpCheckRWX(ent, acc) = {
match acc {
Read(Data) => ent.R() == 0b1,
Write(Data) => ent.W() == 0b1,
ReadWrite(Data) => ent.R() == 0b1 & ent.W() == 0b1,
Execute() => ent.X() == 0b1
}
}
// this needs to be called with the effective current privilege.
val pmpCheckPerms: (Pmpcfg_ent, AccessType(ext_access_type), Privilege) -> bool
function pmpCheckPerms(ent, acc, priv) = {
match priv {
Machine => if ent.L() == 0b1
then pmpCheckRWX(ent, acc)
else true,
_ => pmpCheckRWX(ent, acc)
}
}
/* matching logic */
enum pmpAddrMatch = {PMP_NoMatch, PMP_PartialMatch, PMP_Match}
function pmpMatchAddr(addr: xlenbits, width: xlenbits, rng: pmp_addr_range) -> pmpAddrMatch = {
match rng {
None() => PMP_NoMatch,
Some((lo, hi)) => if hi <_u lo /* to handle mis-configuration */
then PMP_NoMatch
else {
if (addr + width <_u lo) | (hi <_u addr)
then PMP_NoMatch
else if (lo <=_u addr) & (addr + width <=_u hi)
then PMP_Match
else PMP_PartialMatch
}
}
}
enum pmpMatch = {PMP_Success, PMP_Continue, PMP_Fail}
function pmpMatchEntry(addr: xlenbits, width: xlenbits, acc: AccessType(ext_access_type), priv: Privilege,
ent: Pmpcfg_ent, pmpaddr: xlenbits, prev_pmpaddr: xlenbits) -> pmpMatch = {
let rng = pmpAddrRange(ent, pmpaddr, prev_pmpaddr);
match pmpMatchAddr(addr, width, rng) {
PMP_NoMatch => PMP_Continue,
PMP_PartialMatch => PMP_Fail,
PMP_Match => if pmpCheckPerms(ent, acc, priv)
then PMP_Success
else PMP_Fail
}
}
/* priority checks */
function pmpCheck forall 'n, 'n > 0. (addr: xlenbits, width: atom('n), acc: AccessType(ext_access_type), priv: Privilege)
-> option(ExceptionType) = {
let width : xlenbits = to_bits(sizeof(xlen), width);
let check : bool =
match pmpMatchEntry(addr, width, acc, priv, pmp0cfg, pmpaddr0, zeros()) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp1cfg, pmpaddr1, pmpaddr0) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp2cfg, pmpaddr2, pmpaddr1) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp3cfg, pmpaddr3, pmpaddr2) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp4cfg, pmpaddr4, pmpaddr3) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp5cfg, pmpaddr5, pmpaddr4) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp6cfg, pmpaddr6, pmpaddr5) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp7cfg, pmpaddr7, pmpaddr6) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp8cfg, pmpaddr8, pmpaddr7) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp9cfg, pmpaddr9, pmpaddr8) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp10cfg, pmpaddr10, pmpaddr9) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp11cfg, pmpaddr11, pmpaddr10) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp12cfg, pmpaddr12, pmpaddr11) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp13cfg, pmpaddr13, pmpaddr12) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp14cfg, pmpaddr14, pmpaddr13) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue =>
match pmpMatchEntry(addr, width, acc, priv, pmp15cfg, pmpaddr15, pmpaddr14) {
PMP_Success => true,
PMP_Fail => false,
PMP_Continue => match priv {
Machine => true,
_ => false
}
}}}}}}}}}}}}}}}};
if check
then None()
else match acc {
Read(Data) => Some(E_Load_Access_Fault()),
Write(Data) => Some(E_SAMO_Access_Fault()),
ReadWrite(Data) => Some(E_SAMO_Access_Fault()),
Execute() => Some(E_Fetch_Access_Fault())
}
}
function init_pmp() -> unit = {
pmp0cfg = update_A(pmp0cfg, pmpAddrMatchType_to_bits(OFF));
pmp1cfg = update_A(pmp1cfg, pmpAddrMatchType_to_bits(OFF));
pmp2cfg = update_A(pmp2cfg, pmpAddrMatchType_to_bits(OFF));
pmp3cfg = update_A(pmp3cfg, pmpAddrMatchType_to_bits(OFF));
pmp4cfg = update_A(pmp4cfg, pmpAddrMatchType_to_bits(OFF));
pmp5cfg = update_A(pmp5cfg, pmpAddrMatchType_to_bits(OFF));
pmp6cfg = update_A(pmp6cfg, pmpAddrMatchType_to_bits(OFF));
pmp7cfg = update_A(pmp7cfg, pmpAddrMatchType_to_bits(OFF));
pmp8cfg = update_A(pmp8cfg, pmpAddrMatchType_to_bits(OFF));
pmp9cfg = update_A(pmp9cfg, pmpAddrMatchType_to_bits(OFF));
pmp10cfg = update_A(pmp10cfg, pmpAddrMatchType_to_bits(OFF));
pmp11cfg = update_A(pmp11cfg, pmpAddrMatchType_to_bits(OFF));
pmp12cfg = update_A(pmp12cfg, pmpAddrMatchType_to_bits(OFF));
pmp13cfg = update_A(pmp13cfg, pmpAddrMatchType_to_bits(OFF));
pmp14cfg = update_A(pmp14cfg, pmpAddrMatchType_to_bits(OFF));
pmp15cfg = update_A(pmp15cfg, pmpAddrMatchType_to_bits(OFF))
}
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