Cheri-research/cheri-cap-lib
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Add safe maskAddr function

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This commit is contained in:
Peter Rugg
2019-09-05 12:10:11 +01:00
parent bc9f058976
commit a39fefd950
2 changed files with 17 additions and 6 deletions
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13
CHERICC_Fat.bsv
View File

@@ -849,7 +849,7 @@ typedef struct {
TempFields tempFields;
} CapPipe deriving (Bits, FShow);
instance CHERICap #(CapMem, OTypeW, FlagsW, CapAddressW, CapW);
instance CHERICap #(CapMem, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
function isValidCap (x);
CapabilityInMemory capMem = unpack(x);
return capMem.isCapability;
@@ -870,6 +870,7 @@ instance CHERICap #(CapMem, OTypeW, FlagsW, CapAddressW, CapW);
function setType = error("feature not implemented for this cap type");
function getAddr = error("feature not implemented for this cap type");
function setAddr = error("feature not implemented for this cap type");
function maskAddr = error("feature not implemented for this cap type");
function getOffset = error("feature not implemented for this cap type");
function setOffset = error("feature not implemented for this cap type");
function getBase = error("feature not implemented for this cap type");
@@ -885,7 +886,7 @@ instance CHERICap #(CapMem, OTypeW, FlagsW, CapAddressW, CapW);
function toMem = error("feature not implemented for this cap type");
endinstance
instance CHERICap #(CapReg, OTypeW, FlagsW, CapAddressW, CapW);
instance CHERICap #(CapReg, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
function isValidCap = error("feature not implemented for this cap type");
function setValidCap = error("feature not implemented for this cap type");
function getFlags = error("feature not implemented for this cap type");
@@ -899,6 +900,7 @@ instance CHERICap #(CapReg, OTypeW, FlagsW, CapAddressW, CapW);
function setType = error("feature not implemented for this cap type");
function getAddr = error("feature not implemented for this cap type");
function setAddr = error("feature not implemented for this cap type");
function maskAddr = error("feature not implemented for this cap type");
function getOffset = error("feature not implemented for this cap type");
function setOffset = error("feature not implemented for this cap type");
function getBase = error("feature not implemented for this cap type");
@@ -914,7 +916,7 @@ instance CHERICap #(CapReg, OTypeW, FlagsW, CapAddressW, CapW);
function toMem = error("feature not implemented for this cap type");
endinstance
instance CHERICap #(CapPipe, OTypeW, FlagsW, CapAddressW, CapW);
instance CHERICap #(CapPipe, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
function isValidCap (x) = x.capFat.isCapability;
@@ -1004,6 +1006,11 @@ instance CHERICap #(CapPipe, OTypeW, FlagsW, CapAddressW, CapW);
return Exact {exact: result.v, value: cap};
endfunction
function CapPipe maskAddr (CapPipe cap, Bit#(TSub#(MW, 3)) mask);
cap.capFat.addrBits[valueOf(TSub#(MW, 4)):0] = cap.capFat.addrBits[valueOf(TSub#(MW, 4)):0] & mask;
return cap;
endfunction
function getOffset (x) = getOffsetFat(x.capFat, x.tempFields);
function Exact#(CapPipe) setOffset (CapPipe cap, Bit#(CapAddressW) offset, Bool increment);

10
CHERICap.bsv
View File

@@ -78,8 +78,8 @@ typedef enum {
SEALED_WITH_TYPE
} Kind deriving (Bits, Eq, FShow);
typeclass CHERICap#(type t, numeric type ot, numeric type flg, numeric type n, numeric type mem_sz)
dependencies (t determines (ot, flg, n, mem_sz));
typeclass CHERICap#(type t, numeric type ot, numeric type flg, numeric type n, numeric type mem_sz, numeric type maskable_bits)
dependencies (t determines (ot, flg, n, mem_sz, maskable_bits));
// Return whether the Capability is valid
function Bool isValidCap (t cap);
@@ -123,6 +123,10 @@ typeclass CHERICap#(type t, numeric type ot, numeric type flg, numeric type n, n
function Bit#(n) getAddr (t cap);
// Set the address of the capability. Result invalid if not exact
function Exact#(t) setAddr (t cap, Bit#(n) addr);
// Mask the least significant bits of capability address with a mask
// maskable_width should be small enough to make this
// safe with respect to representability
function t maskAddr (t cap, Bit#(maskable_bits) mask);
// Get the offset of the capability
function Bit#(n) getOffset (t cap) = getAddr(cap) - getBase(cap);
@@ -164,7 +168,7 @@ typeclass CHERICap#(type t, numeric type ot, numeric type flg, numeric type n, n
endtypeclass
function Fmt showCHERICap(t cap) provisos (CHERICap#(t, ot, flg, n, mem_sz));
function Fmt showCHERICap(t cap) provisos (CHERICap#(t, ot, flg, n, mem_sz, maskable_bits));
return $format( "Valid: 0x%0x", isValidCap(cap)) +
$format(" Perms: 0x%0x", getPerms(cap)) +
$format(" Kind: ", fshow(getKind(cap))) +