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cheri-cap-lib/CHERICC_Fat.bsv
Jonathan Woodruff cbd0b2f7f5 Add a couple of casts for functions that return capabilities. 
This is necessary for passing the register file read functions into modules that want to read the Pipe format rather than the Reg format.
2020-03-31 15:41:19 +01:00

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/*
* Copyright (c) 2015-2019 Jonathan Woodruff
* Copyright (c) 2017-2019 Alexandre Joannou
* Copyright (c) 2019 Peter Rugg
* All rights reserved.
*
* This software was developed by SRI International and the University of
* Cambridge Computer Laboratory under DARPA/AFRL contract FA8750-10-C-0237
* ("CTSRD"), as part of the DARPA CRASH research programme.
*
* @BERI_LICENSE_HEADER_START@
*
* Licensed to BERI Open Systems C.I.C. (BERI) under one or more contributor
* license agreements. See the NOTICE file distributed with this work for
* additional information regarding copyright ownership. BERI licenses this
* file to you under the BERI Hardware-Software License, Version 1.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at:
*
* http://www.beri-open-systems.org/legal/license-1-0.txt
*
* Unless required by applicable law or agreed to in writing, Work distributed
* under the 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.
*
* @BERI_LICENSE_HEADER_END@
*/
package CHERICC_Fat;
import DefaultValue :: *;
import CHERICap :: *;
export CapMem;
export CapReg;
export CapPipe;
// -----
// Auxiliary requried imports. TODO find a way around this?
export CapFat;
export MW;
export OTypeW;
export FlagsW;
export Perms;
export ResW;
export LCapAddress;
export Format;
export TempFields;
export Bounds;
export UPermW;
export CapW;
export ExpW;
export CapAddressW;
export CBoundsW;
export HPerms;
export PermsW;
export Exp;
export MetaInfo;
// ===============================================================================
typedef struct {
Bool v;
t d;
} VnD#(type t) deriving (Bits);
// ===============================================================================
`ifdef RISCV
`define FLAGSW 1
`else // MIPS format with 0-width flags width XXX
`define FLAGSW 0
`endif
`ifdef CAP64
typedef 0 UPermW;
typedef 8 MW;
typedef 6 ExpW;
typedef 4 OTypeW;
typedef `FLAGSW FlagsW;
typedef 32 CapAddressW;
typedef 64 CapW;
`else // CAP128 is default
typedef 4 UPermW;
typedef 14 MW;
typedef 6 ExpW;
typedef 18 OTypeW;
typedef `FLAGSW FlagsW;
typedef 64 CapAddressW;
typedef 128 CapW;
`endif
typedef Bit#(CapAddressW) Address;
typedef TDiv#(ExpW,2) HalfExpW;
typedef TSub#(MW,HalfExpW) UpperMW;
// The compressed bounds field type
typedef TSub#(TMul#(MW,2),1) CBoundsW;
typedef Bit#(CBoundsW) CBounds;
// The pointer CapAddress type
typedef Bit#(CapAddressW) CapAddress;
// The Hardware permissions type
typedef struct {
Bool permit_set_CID;
Bool access_sys_regs;
Bool permit_unseal;
Bool permit_ccall;
Bool permit_seal;
Bool permit_store_ephemeral_cap;
Bool permit_store_cap;
Bool permit_load_cap;
Bool permit_store;
Bool permit_load;
Bool permit_execute;
Bool non_ephemeral;
} HPerms deriving(Bits, Eq, FShow); // 12 bits
// The permissions field, including both "soft" and "hard" permission bits.
typedef struct {
Bit#(UPermW) soft;
HPerms hard;
} Perms deriving(Bits, Eq, FShow);
typedef SizeOf#(Perms) PermsW;
// The reserved bits
typedef TSub#(CapW,TAdd#(CapAddressW,TAdd#(OTypeW,TAdd#(CBoundsW,TAdd#(PermsW, FlagsW))))) ResW;
// The full capability structure, including the "tag" bit.
typedef struct {
Bool isCapability;
Perms perms;
Bit#(ResW) reserved;
Bit#(FlagsW) flags;
Bit#(OTypeW) otype;
CBounds bounds;
CapAddress address;
} CapabilityInMemory deriving(Bits, Eq, FShow); // CapW + 1 (tag bit)
// The full capability structure as Bits, including the "tag" bit.
typedef Bit#(TAdd#(CapW,1)) Capability;
// not including the tag bit
typedef Bit#(CapW) CapBits;
typedef Bit#(128) ShortCap;
/* TODO
staticAssert(valueOf(SizeOf#(CapabilityInMemory))==valueOf(SizeOf#(Capability)),
"The CapabilityInMemory type has incorrect size of " + integerToString(valueOf(SizeOf#(CapabilityInMemory))) + " (CapW = " + integerToString(valueOf(CapW)) + ")"
);
*/
// Bit type of the debug capability
typedef Bit#(CapW) DebugCap;
// large capability address type (with extra bits at the top)
typedef Bit#(TAdd#(CapAddressW,2)) LCapAddress;
// Format of the cheri concentrate capability
typedef enum {Exp0, EmbeddedExp} Format deriving (Bits, Eq, FShow);
// Exponent type
typedef UInt#(ExpW) Exp;
// Type for capability otype field
typedef VnD#(Bit#(OTypeW)) CType;
Bit#(OTypeW) otype_max = -5;
Bit#(OTypeW) otype_unsealed = -1;
Bit#(OTypeW) otype_sentry = -2;
// unpacked capability format
typedef struct {
Bool isCapability;
LCapAddress address;
Bit#(MW) addrBits;
Perms perms;
Bit#(FlagsW) flags;
Bit#(ResW) reserved;
Bit#(OTypeW) otype;
Format format;
Bounds bounds;
} CapFat deriving(Bits, Eq);
// "Architectural FShow"
function Fmt showArchitectural(CapFat cap) =
$format("valid:%b", cap.isCapability)
+ $format(" perms:0x%x", getPerms(cap))
//+ $format(" flags:0x%x", getFlags(cap))
+ $format(" sealed:%b", isSealed(cap))
+ $format(" type:0x%x",getType(cap))
+ $format(" offset:0x%x", getOffsetFat(cap, getTempFields(cap)))
+ $format(" base:0x%x", getBotFat(cap, getTempFields(cap)))
+ $format(" length:0x%x", getLengthFat(cap, getTempFields(cap)));
// "Microarchitectural FShow"
instance FShow#(CapFat);
function Fmt fshow(CapFat cap) =
$format("valid:%b", cap.isCapability)
+ $format(" perms:0x%x", getPerms(cap))
//+ $format(" flags:0x%x", getFlags(cap))
+ $format(" reserved:0x%x", cap.reserved)
+ $format(" format:", fshow(cap.format))
+ $format(" bounds:", fshow(cap.bounds))
+ $format(" address:0x%x", cap.address)
+ $format(" addrBits:0x%x", cap.addrBits)
+ $format(" {bot:0x%x top:0x%x len:0x%x offset:0x%x}",
getBotFat(cap, getTempFields(cap)),
getTopFat(cap, getTempFields(cap)),
getLengthFat(cap, getTempFields(cap)),
getOffsetFat(cap, getTempFields(cap)))
+ $format(" (TempFields: {") + fshow(getTempFields(cap)) + $format("})");
endinstance
// default value for CatFat
CapFat defaultCapFat = defaultValue;
// Capability register index type
typedef Bit#(6) CapRegIdx;
// unpack a memory representation of the capability
function CapFat unpackCap(Capability thin);
CapabilityInMemory memCap = unpack(thin);
// extract the fields from the memory capability
CapFat fat = defaultValue;
fat.isCapability = memCap.isCapability;
fat.perms = memCap.perms;
fat.flags = memCap.flags;
fat.reserved = memCap.reserved;
fat.otype = memCap.otype;
match {.f, .b} = decBounds(memCap.bounds);
fat.format = f;
fat.bounds = b;
fat.address = zeroExtend(memCap.address);
// The next few lines are to optimise the critical path of generating addrBits.
// The value of Exp can now be 0 or come from token, so assume they come from the token,
// then select the lower bits at the end if they didn't after all.
BoundsEmbeddedExp tmp = unpack(memCap.bounds);
Exp potentialExp = unpack({tmp.expTopHalf,tmp.expBotHalf});
Bit#(MW) potentialAddrBits = truncate(memCap.address >> potentialExp);
fat.addrBits = (tmp.embeddedExp)?potentialAddrBits:truncate(memCap.address);
return fat;
endfunction
// pack the fat capability into the memory representation
function Capability packCap(CapFat fat);
CapabilityInMemory thin = CapabilityInMemory{
isCapability: fat.isCapability,
perms: fat.perms,
flags: fat.flags,
reserved: fat.reserved,
otype: fat.otype,
bounds: encBounds(fat.format,fat.bounds),
address: truncate(fat.address)
};
return pack(thin);
endfunction
// XXX needs double checking
function ShortCap getShortCap (CapFat cap);
CapabilityInMemory ret = unpack(packCap(cap));
// put tag bit in highest reserved bit
if (valueOf(ResW)!=0) ret.reserved[valueOf(ResW)-1] = pack(cap.isCapability);
CapBits retbits = truncate(pack(ret));
return zeroExtend(retbits);
endfunction
// The temporary fields
typedef MetaInfo TempFields;
// Is the capability format imprecise
Bool imprecise = True;
// Interface functions
//------------------------------------------------------------------------------
function LCapAddress getBotFat(CapFat cap, TempFields tf);
// First, construct a full length value with the base bits and the
// correction bits above, and shift that value to the appropriate spot.
CapAddress addBase = signExtend({pack(tf.baseCorrection), cap.bounds.baseBits}) << cap.bounds.exp;
// Build a mask on the high bits of a full length value to extract the high
// bits of the address.
Bit#(TSub#(SizeOf#(CapAddress),MW)) mask = ~0 << cap.bounds.exp;
// Extract the high bits of the address (and append the implied zeros at the
// bottom), and add with the previously prepared value.
CapAddress adr = truncate(cap.address); // Trim top bits of address.
CapAddress bot = {truncateLSB(adr)&mask,0} + addBase;
return zeroExtend(bot);
endfunction
function LCapAddress getTopFat(CapFat cap, TempFields tf);
// First, construct a full length value with the top bits and the
// correction bits above, and shift that value to the appropriate spot.
LCapAddress addTop = signExtend({pack(tf.topCorrection), cap.bounds.topBits}) << cap.bounds.exp;
// Build a mask on the high bits of a full length value to extract the high
// bits of the address.
Bit#(TSub#(SizeOf#(LCapAddress),MW)) mask = ~0 << cap.bounds.exp;
// Extract the high bits of the address (and append the implied zeros at the
// bottom), and add with the previously prepared value.
LCapAddress ret = {truncateLSB(cap.address)&mask,0} + addTop;
// If the bottom and top are more than an address space away from eachother, invert
// the 64th/32nd bit of Top. This corrects for errors that happen when the representable
// space wraps the address space.
Integer msbp = valueOf(CapAddressW) - 1;
ret[msbp+2] = 0;
Bit#(2) topTip = ret[msbp+1:msbp];
// Calculate the msb of the base.
CapAddress adr = truncate(cap.address);
// First assume that only the address and correction are involved...
Bit#(TSub#(SizeOf#(CapAddress),MW)) bot = truncateLSB(adr) + (signExtend(pack(tf.baseCorrection)) << cap.bounds.exp);
Bit#(1) botTip = msb(bot);
// If the bit we're interested in are actually coming from baseBits, select the correct one from there.
// exp == (resetExp - 1) doesn't matter since we will not flip unless exp < resetExp-1.
if (cap.bounds.exp == (resetExp - 2)) botTip = cap.bounds.baseBits[valueOf(MW)-1];
// Do the final check.
// If exp >= resetExp - 1, the bits we're looking at are coming directly from topBits and baseBits, are not being inferred,
// and therefore do not need correction. If we are below this range, check that the difference between the resulting top and
// bottom is less than one address space. If not, flip the msb of the top.
if (cap.bounds.exp<(resetExp-1) && (topTip - zeroExtend(botTip)) > 1) ret[msbp+1] = ~ret[msbp+1];
return ret;
endfunction
function LCapAddress getLengthFat(CapFat cap, TempFields tf);
// Get the top and base bits with the 2 correction bits prepended
Bit#(TAdd#(MW,2)) top = {pack(tf.topCorrection),cap.bounds.topBits};
Bit#(TAdd#(MW,2)) base = {pack(tf.baseCorrection),cap.bounds.baseBits};
// Get the length by substracting base from top and shifting appropriately
LCapAddress length = zeroExtend(top - base) << cap.bounds.exp;
// Return a saturated length in case of big exponent
return (cap.bounds.exp >= resetExp) ? ~0 : length;
endfunction
function Address getOffsetFat(CapFat cap, TempFields tf);
// Get the exponent
Exp e = cap.bounds.exp;
// Get the base bits with the 2 correction bits prepended
Bit#(TAdd#(MW,2)) base = {pack(tf.baseCorrection),cap.bounds.baseBits};
// Get the offset bits by substracting the previous value from the addrBits
Bit#(TAdd#(MW,2)) offset = zeroExtend(cap.addrBits) - base;
// Grab the bottom bits of the address
Address addrLSB = lAddrToReg(cap.address & ~(~0 << e));
// Return the computed offset bits (sign extended) shifted appropriatly,
// with the low address bits appended
return (signExtend(offset) << e) | addrLSB;
endfunction
function LCapAddress getAddress(CapFat cap) = cap.address;
function Address lAddrToReg(LCapAddress in);
CapAddress retVal = truncate(in);
return signExtend(retVal);
endfunction
function LCapAddress regToLAddr(Address in);
CapAddress retVal = truncate(in);
return zeroExtend(retVal);
endfunction
function LCapAddress regToSignedLAddr(Address in);
CapAddress retVal = truncate(in);
return signExtend(retVal);
endfunction
function Bool isSealed(CapFat cap) = (cap.otype != otype_unsealed);
function CType getTypeFat(CapFat cap) = VnD{v: (cap.otype != otype_unsealed), d: cap.otype};
function Bit#(31) getPerms(CapFat cap);
Bit#(SizeOf#(HPerms)) hardPerms = zeroExtend(pack(cap.perms.hard));
Bit#(UPermW) softPerms = zeroExtend(pack(cap.perms.soft));
return zeroExtend({softPerms,hardPerms});
endfunction
function TempFields getTempFields(CapFat cap) = getMetaInfo(cap);
function Bool privileged(CapFat cap) = cap.perms.hard.access_sys_regs;
function Bool capInBounds(CapFat cap, TempFields tf, Bool inclusive);
// Check that the pointer of a capability is currently within the bounds
// of the capability
Bool ptrVStop = (inclusive) ? (cap.addrBits<=cap.bounds.topBits) : (cap.addrBits<cap.bounds.topBits);
// Top is ok if the pointer and top are in the same alignment region
// and the pointer is less than the top. If they are not in the same
// alignment region, it's ok if the top is in Hi and the bottom in Low.
Bool topOk = (tf.topHi == tf.addrHi) ? (ptrVStop) : tf.topHi;
Bool baseOk = (tf.baseHi == tf.addrHi) ? (cap.addrBits >= cap.bounds.baseBits) : tf.addrHi;
return topOk && baseOk;
endfunction
function CapFat nullifyCap(CapFat cap);
CapFat ret = nullCap;
CapAddress tmpAddr = truncate(cap.address);
ret.addrBits = {2'b0,truncateLSB(tmpAddr)};
ret.address = cap.address;
//CapFat ret = cap;
//ret.isCapability = False;
return ret;
endfunction
function CapFat pccJumpUpdate(CapFat pcc, LCapAddress fullBot);
// Set the appropriate fields in PCC when jumping.
pcc.address = fullBot;
pcc.addrBits = pcc.bounds.baseBits;
return pcc;
endfunction
function CapFat setCapPointer(CapFat cap, LCapAddress pointer);
// Function to "cheat" and just set the pointer when we know that
// it will be in representable bounds by some other means.
CapFat ret = cap;
ret.address = pointer;
ret.addrBits = truncate(ret.address >> ret.bounds.exp);
return ret;
endfunction
// Only currently used for algorithm comparison.
function Bool boundsCheck(CapFat cap, Bit#(CapAddressW) off, TempFields tf);
Bit#(TAdd#(CapAddressW,2)) bo = zeroExtend(off);
cap = incOffsetFat(cap, cap.address+truncate(bo), off, tf, False).d;
return cap.isCapability && capInBounds(cap, tf, False);
endfunction
function Bit#(n) smearMSBRight(Bit#(n) x);
Bit#(n) res = x;
for (Integer i = 0; i < valueOf(TLog#(n))-1; i = i + 1)
res = res | (res >> 2**i);
return res;
endfunction
typedef struct
{
CapFat cap;
Bool exact;
CapAddress length;
CapAddress mask;
} SetBoundsReturn deriving (Bits, Eq, FShow);
function SetBoundsReturn setBoundsFat(CapFat cap, Address lengthFull);
CapFat ret = cap;
// Find new exponent by finding the index of the most significant bit of the
// length, or counting leading zeros in the high bits of the length, and
// substracting them to the CapAddress width (taking away the bottom MW-1 bits:
// trim (MW-1) bits from the bottom of length since any length with a significance
// that small will yield an exponent of zero).
CapAddress length = truncate(lengthFull);
Bit#(TSub#(CapAddressW,TSub#(MW,1))) lengthMSBs = truncateLSB(length);
Exp zeros = zeroExtend(countZerosMSB(lengthMSBs));
// Adjust resetExp by one since it's scale reaches 1-bit greater than a 64-bit length
// can express.
Bool maxZero = (zeros==(resetExp-1));
Bool intExp = !(maxZero && length[fromInteger(valueOf(TSub#(MW,2)))]==1'b0);
// Do this without subtraction
//fromInteger(valueof(TSub#(SizeOf#(Address),TSub#(MW,1)))) - zeros;
Exp e = (resetExp-1) - zeros;
// Force otype to unsealed.
ret.otype = otype_unsealed;
// Derive new base bits by extracting MW bits from the capability
// address starting at the new exponent's position.
CapAddress tmpAddr = truncate(cap.address);
LCapAddress base = zeroExtend(tmpAddr);
Bit#(TAdd#(MW,1)) newBaseBits = truncate(base>>e);
// Derive new top bits by extracting MW bits from the capability
// address + requested length, starting at the new exponent's position,
// and rounding up if significant bits are lost in the process.
LCapAddress len = zeroExtend(length);
LCapAddress top = base + len;
// Create a mask with all bits set below the MSB of length and then masking all bits
// below the mantissa bits.
LCapAddress lmask = smearMSBRight(len);
// The shift amount required to put the most significant set bit of the
// len just above the bottom HalfExpW bits that are taken by the exp.
Integer shiftAmount = valueOf(TSub#(TSub#(MW,2),HalfExpW));
// Calculate all values associated with E=e (e not rounding up)
// Round up considering the stolen HalfExpW exponent bits if required
Bit#(TAdd#(MW,1)) newTopBits = truncate(top>>e);
// Check if non-zero bits were lost in the low bits of top, either in the 'e'
// shifted out bits or in the HalfExpW bits stolen for the exponent
// Shift by MW-1 to move MSB of mask just below the mantissa, then up HalfExpW
// more to take in the bits that will be lost for the exponent when it is non-zero.
LCapAddress lmaskLor = lmask>>fromInteger(shiftAmount+1);
LCapAddress lmaskLo = lmask>>fromInteger(shiftAmount);
// For the len, we're not actually losing significance since we're not storing it,
// we just want to know if any low bits are non-zero so that we will know if it will
// cause the total length to round up.
Bool lostSignificantLen = (len&lmaskLor)!=0 && intExp;
Bool lostSignificantTop = (top&lmaskLor)!=0 && intExp;
// Check if non-zero bits were lost in the low bits of base, either in the 'e'
// shifted out bits or in the HalfExpW bits stolen for the exponent
Bool lostSignificantBase = (base&lmaskLor)!=0 && intExp;
// Calculate all values associated with E=e+1 (e rounding up due to msb of L increasing by 1)
// This value is just to avoid adding later.
Bit#(MW) newTopBitsHigher = truncateLSB(newTopBits);
// Check if non-zero bits were lost in the low bits of top, either in the 'e'
// shifted out bits or in the HalfExpW bits stolen for the exponent
// Shift by MW-1 to move MSB of mask just below the mantissa, then up HalfExpW
// more to take in the bits that will be lost for the exponent when it is non-zero.
Bool lostSignificantTopHigher = (top&lmaskLo)!=0 && intExp;
// Check if non-zero bits were lost in the low bits of base, either in the 'e'
// shifted out bits or in the HalfExpW bits stolen for the exponent
Bool lostSignificantBaseHigher = (base&lmaskLo)!=0 && intExp;
// If either base or top lost significant bits and we wanted an exact setBounds,
// void the return capability
// We need to round up Exp if the msb of length will increase.
// We can check how much the length will increase without looking at the result of adding the
// length to the base. We do this by adding the lower bits of the length to the base and then
// comparing both halves (above and below the mask) to zero. Either side that is non-zero indicates
// an extra "1" that will be added to the "mantissa" bits of the length, potentially causing overflow.
// Finally check how close the requested length is to overflow, and test in relation to how much the
// length will increase.
LCapAddress topLo = (lmaskLor & len) + (lmaskLor & base);
LCapAddress mwLsbMask = lmaskLor ^ lmaskLo;
// If the first bit of the mantissa of the top is not the sum of the corrosponding bits of base and length, there was a carry in.
Bool lengthCarryIn = (mwLsbMask & top) != ((mwLsbMask & base)^(mwLsbMask & len));
Bool lengthRoundUp = lostSignificantTop;
Bool lengthIsMax = (len & (~lmaskLor)) == (lmask ^ lmaskLor);
Bool lengthIsMaxLessOne = (len & (~lmaskLor)) == (lmask ^ lmaskLo);
Bool lengthOverflow = False;
if (lengthIsMax && (lengthCarryIn || lengthRoundUp)) lengthOverflow = True;
if (lengthIsMaxLessOne && lengthCarryIn && lengthRoundUp) lengthOverflow = True;
if(lengthOverflow && intExp) begin
e = e+1;
ret.bounds.topBits = (lostSignificantTopHigher) ? (newTopBitsHigher+'b1000):newTopBitsHigher;
ret.bounds.baseBits = truncateLSB(newBaseBits);
end else begin
ret.bounds.topBits = (lostSignificantTop) ? truncate(newTopBits+'b1000):truncate(newTopBits);
ret.bounds.baseBits = truncate(newBaseBits);
end
Bool exact = !(lostSignificantBase || lostSignificantTop);
ret.bounds.exp = e;
// Update the addrBits fields
ret.addrBits = ret.bounds.baseBits;
// Derive new format from newly computed exponent value, and round top up if
// necessary
if (!intExp) begin // If we have an Exp of 0 and no implied MSB of L.
ret.format = Exp0;
end else begin
ret.format = EmbeddedExp;
Bit#(HalfExpW) botZeroes = 0;
ret.bounds.baseBits = {truncateLSB(ret.bounds.baseBits), botZeroes};
ret.bounds.topBits = {truncateLSB(ret.bounds.topBits), botZeroes};
end
// Begin calculate newLength in case this is a request just for a representable length:
LCapAddress newLength = zeroExtend(length);
if (intExp) begin
LCapAddress oneInLsb = (lmask ^ (lmask>>1)) >> shiftAmount;
LCapAddress newLengthRounded = newLength + oneInLsb;
newLength = (newLength & (~lmaskLor));
newLengthRounded = (newLengthRounded & (~lmaskLor));
if (lostSignificantLen) newLength = newLengthRounded;
end
LCapAddress baseMask = (lengthIsMax && lostSignificantTop) ? ~lmaskLo:~lmaskLor;
// Return derived capability
return SetBoundsReturn{cap: ret, exact: exact, length: truncate(newLength), mask: truncate(baseMask)};
endfunction
function CapFat seal(CapFat cap, TempFields tf, CType otype);
CapFat ret = cap;
// Update the fields of the new sealed capability (otype)
ret.otype = otype.d;
return ret;
endfunction
function CapFat unseal(CapFat cap, x _);
CapFat ret = cap;
ret.otype = otype_unsealed;
return ret;
endfunction
function VnD#(CapFat) incOffsetFat(CapFat cap, LCapAddress pointer, Bit#(CapAddressW) offset/*this is the increment in inc offset, and the offset in set offset*/, TempFields tf, Bool setOffset);
// NOTE:
// The 'offset' argument is the "increment" value when setOffset is false,
// and the actual "offset" value when setOffset is true.
//
// For this function to work correctly, we must have 'offset' = 'pointer'-'cap.address'.
// In the most critical case we have both available and picking one or the other
// is less efficient than passing both. If the 'setOffset' flag is set, this function will
// ignore the 'pointer' argument and use 'offset' to set the offset of 'cap' by adding it to
// the capability base. If the 'setOffset' flag is not set, this function will increment the
// offset of 'cap' by replacing the 'cap.address' field with the 'pointer' argument (with
// the assumption that the 'pointer' argument is indeed equal to 'cap.address'+'offset'.
// The 'cap.addrBits' field is also updated accordingly.
CapFat ret = cap;
Exp e = cap.bounds.exp;
// Updating the address of a capability requires checking that the new address
// is still within representable bounds. For capabilities with big representable
// regions (with exponents >= resetExp-2), there is no representability issue.
// For the other capabilities, the check consists of two steps:
// - A "inRange" test
// - A "inLimits" test
// The inRange test
// ----------------
// Conceptually, the inRange test checks the magnitude of 'offset' is less then
// the representable region’s size S. This ensures that the inLimits test result
// is meaningful. The test succeeds if the absolute value of 'offset' is less than S,
// that is −S < 'offset' < S. This test reduces to a check that there are no
// significant bits in the high bits of 'offset', that is they are all ones or all
// zeros.
CapAddress offsetAddr = truncate(offset);
Bit#(TSub#(CapAddressW,MW)) signBits = signExtend(offset[valueOf(TSub#(CapAddressW,1))]);
Bit#(TSub#(CapAddressW,MW)) highOffsetBits = unpack(truncateLSB(offsetAddr));
Bit#(TSub#(CapAddressW,MW)) highBitsfilter = -1 << e;
highOffsetBits = (highOffsetBits ^ signBits) & highBitsfilter;
Bool inRange = (highOffsetBits == 0);
// The inLimits test
// -----------------
// Conceptually, the inLimits test ensures that neither the of the edges of the
// representable region have been crossed with the new address. In essence, it
// compares the distance 'offsetBits' added (on MW bits) with the distance 'toBounds'
// to the edge of the representable space (on MW bits).
// - For a positive or null increment
// inLimits = offsetBits < toBounds - 1
// - For a negative increment:
// inLimits = (offsetBits >= toBounds) and ('we were not already on the bottom edge')
// (when already on the bottom edge of the representable space, the relevant
// bits of the address and those of the representable edge are the same, leading
// to a false positive on the i >= toBounds comparison)
// The sign of the increment
Bool posInc = offsetAddr[valueOf(CapAddressW)-1] == 1'b0;
// The offsetBits value corresponds to the appropriate slice of the 'offsetAddr' argument
Bit#(MW) offsetBits = truncate(offsetAddr >> e);
// The toBounds value is given by substracting the address of the capability from the
// address of the edge of the representable region (on MW bits) when the 'setOffset'
// flag is not set. When it is set, it is given by substracting the base address of
// the capability from the edge of the representable region (on MW bits).
// This value is both the distance to the representable top and the distance to the
// representable bottom (when appended to a one for negative sign), a convenience of
// the two's complement representation.
// NOTE: When the setOffset flag is set, toBounds should be the distance from the base
// to the representable edge. This can be computed efficiently, and without relying on
// the temporary fields, as follows:
// equivalent to (repBoundBits - cap.bounds.baseBits):
Bit#(MW) toBounds_A = {3'b111,0} - {3'b000,truncate(cap.bounds.baseBits)};
// equivalent to (repBoundBits - cap.bounds.baseBits - 1):
Bit#(MW) toBoundsM1_A = {3'b110,~truncate(cap.bounds.baseBits)};
/*
XXX not sure if we still care about that
if (toBoundsM1_A != (toBounds_A-1)) $display("error %x", toBounds_A[15:13]);
*/
// When the setOffset flag is not set, we need to use the temporary fields with the
// upper bits of the representable bounds
Bit#(MW) repBoundBits = {tf.repBoundTopBits,0};
Bit#(MW) toBounds_B = repBoundBits - cap.addrBits;
Bit#(MW) toBoundsM1_B = repBoundBits + ~cap.addrBits;
// Select the appropriate toBounds value
Bit#(MW) toBounds = (setOffset) ? toBounds_A : toBounds_B;
Bit#(MW) toBoundsM1 = (setOffset) ? toBoundsM1_A : toBoundsM1_B;
// Implement the inLimit test
Bool inLimits = False;
if (posInc) begin
// For a positive or null increment
inLimits = offsetBits < toBoundsM1;
end else begin
// For a negative increment
inLimits = (offsetBits >= toBounds) && (repBoundBits != cap.addrBits);
end
// Complete representable bounds check
// -----------------------------------
Bool inBounds = (inRange && inLimits) || (e >= (resetExp - 2));
// Updating the return capability
// ------------------------------
if (setOffset) begin
// Get the base and add the offsetAddr. This could be slow, but seems to pass timing.
ret.address = getBotFat(cap,tf) + zeroExtend(offsetAddr);
// TODO write comments on this
Bit#(TAdd#(MW,2)) newAddrBits = zeroExtend(cap.bounds.baseBits) + zeroExtend(offsetBits);
ret.addrBits = (e == resetExp) ? {1'b0,truncate(newAddrBits)}:truncate(newAddrBits);
end else begin
// In the incOffset case, the 'pointer' argument already contains the new address
CapAddress tmpAddr = truncate(pointer);
ret.address = zeroExtend(tmpAddr);
ret.addrBits = truncate(pointer >> e);
end
// Nullify the capability if the representable bounds check has failed
if (!inBounds) ret.isCapability = False;//nullifyCap(ret);
// return updated / invalid capability
return VnD {v: inBounds, d: ret};
endfunction
function VnD#(CapFat) setAddress(CapFat cap, LCapAddress address, TempFields tf);
CapFat ret = setCapPointer(cap, address);
Exp e = cap.bounds.exp;
// Calculate what the upper bits of the new address must be if it is to be in representable bounds.
Bool newAddrHi = truncateLSB(ret.addrBits) < tf.repBoundTopBits;
// Shift amount needed to look at only the bits above the mantissa.
Exp toUpperBits = e + fromInteger(valueOf(MW));
CapAddress mask = -1 << toUpperBits;
CapAddress newAddrDiff = (truncate(cap.address)&mask) - (truncate(address)&mask);
// Assert that the bits above the mantissa are all equal.
Bool inRepBounds = True;
// If the difference between the upper bits of the new address and the current
// address does not match the expected difference, call it outside of representable bounds.
// We construct the "actual" diff assuming that the inRepBounds check above succeeded.
Int#(2) diff = ?;
if (newAddrDiff == 0) diff = 0;
else if (newAddrDiff == mask) diff = -1;
else if (newAddrDiff == (mask^(mask<<1))) diff = 1;
else inRepBounds = False;
let t2 = tuple2;
Int#(2) expectedDiff = case (t2(tf.addrHi,newAddrHi))
t2(True, True): return 0;
t2(True, False): return 1;
t2(False, True): return -1;
t2(False, False): return 0;
endcase;
if (diff != expectedDiff) inRepBounds = False;
if (e >= resetExp - 2) inRepBounds = True;
if (!inRepBounds) ret.isCapability = False;
return VnD {v: inRepBounds, d: ret};
endfunction
///////////////////////////////
// Internal types and values //
////////////////////////////////////////////////////////////////////////////////
// Exponent that pushes the implied +1 of the top 1 bit outside the address space
Exp resetExp = fromInteger(valueOf(TSub#(SizeOf#(LCapAddress),MW)));
Bit#(MW) resetTop = {2'b01,0};
typedef struct
{
Exp exp;
Bit#(MW) topBits;
Bit#(MW) baseBits;
} Bounds deriving (Bits, Eq, FShow);
instance DefaultValue #(Bounds);
defaultValue = Bounds {
exp : resetExp,
topBits : resetTop,
baseBits: 0
};
endinstance
instance DefaultValue #(CapFat);
defaultValue = CapFat {
isCapability: True,
perms : unpack(~0),
flags : 0,
reserved : 0,
otype : otype_unsealed,
format : EmbeddedExp,
bounds : defaultValue,
address : 0,
addrBits : 0
};
endinstance
CapFat null_cap = CapFat {
isCapability: False,
perms : unpack(0),
flags : 0,
reserved : 0,
otype : otype_unsealed,
format : EmbeddedExp,
bounds : defaultValue,
address : 0,
addrBits : 0
};
///////////////////////////////////////////////
// CHERI CONCENTRATE, example 128-bit format //
///////////////////////////////////////////////
// In memory representation //
////////////////////////////////////////////////////////////////////////////////
/*
XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX
XXX Note that the Flags field does not currently appear in the drawing below
XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX XXX
Embedded Exp
127___124_123_112_111_109_108__91__90_89_________________________78_77__________________________64
| | | | | | | |
| uperms | perms | res | otype | 0 | top<11:0>| base<13:0>| Exp0
| uperms | perms | res | | 1 | top<11:3>|e<5:3>| base<13:3>|e<2:0>| EmbeddedExp
|________|_______|_______|_______|___|_____________________________|_____________________________|
63_______________________________________________________________________________________________0
| |
| address |
|________________________________________________________________________________________________|
reconstructing most significant top bits:
top<20:19> = base<20:19> + carry_out + len_correction
where
carry_out = 1 if top<18:0> < base <18:0>
0 otherwise
len_correction = 0 if Exp0
1 otherwise
*/
// These three bounds formats help with the decBounds function.
typedef struct {
Bool embeddedExp;
Bit#(TSub#(MW,2)) top;
Bit#(MW) base;
} BoundsExp0 deriving(Bits, Eq, FShow);
typedef struct {
Bool embeddedExp;
Bit#(TSub#(MW,TAdd#(HalfExpW,2))) topUpperBits;
Bit#(HalfExpW) expTopHalf;
Bit#(TSub#(MW,HalfExpW)) baseUpperBits;
Bit#(HalfExpW) expBotHalf;
} BoundsEmbeddedExp deriving(Bits, Eq, FShow);
function Tuple2#(Format, Bounds) decBounds (CBounds raw);
Bool embeddedExp = (truncateLSB(raw)==1'b1);
Format format = (embeddedExp) ? EmbeddedExp : Exp0;
Bounds bounds = defaultValue;
//bounds.exp = 0;
//bounds.topBits = 0;
//bounds.baseBits = 0;
Bit#(HalfExpW) halfExp0 = 0;
case (format)
EmbeddedExp: begin
BoundsEmbeddedExp b = unpack(raw);
bounds.exp = unpack({b.expTopHalf,b.expBotHalf});
bounds.topBits = {?,b.topUpperBits,halfExp0}; // will supply the top two bits later.
bounds.baseBits = {b.baseUpperBits,halfExp0};
end
default: begin // and Exp0
bounds.exp = 0;
BoundsExp0 b = unpack(raw);
bounds.topBits = {?,b.top}; // will supply the top two bits later.
bounds.baseBits = b.base;
end
endcase
// topBits = baseBits + lengthBits. lengthBits is not present here, but the MSB of lengthBits can be implied to be 1.
// To calculate the upper bits of of top, we need the oritinal carry out from the lower bits of base + length, which we find like so:
Bit#(TSub#(MW,2)) topBits = truncate(bounds.topBits);
Bit#(TSub#(MW,2)) baseBits = truncate(bounds.baseBits);
Bit#(2) carry_out = (topBits < baseBits) ? 2'b01 : 2'b00;
Bit#(2) len_correction = case (format)
Exp0: 2'b00;
default: 2'b01;
endcase;
Bit#(2) impliedTopBits = truncateLSB(bounds.baseBits) + carry_out + len_correction;
bounds.topBits = {impliedTopBits,truncate(bounds.topBits)};
return tuple2(format,bounds);
endfunction
function CBounds encBounds (Format format, Bounds bounds);
Bit#(HalfExpW) hiExpBits = truncateLSB(pack(bounds.exp));
Bit#(HalfExpW) loExpBits = truncate(pack(bounds.exp));
Bit#(TSub#(MW,TAdd#(HalfExpW,2))) eExpTop = truncate(bounds.topBits >> valueOf(HalfExpW));
Bit#(TSub#(MW,HalfExpW)) eExpBase = truncateLSB(bounds.baseBits);
return case (format)
Exp0: {1'b0, truncate(bounds.topBits), bounds.baseBits};
EmbeddedExp: {1'b1, eExpTop, hiExpBits, eExpBase, loExpBits};
endcase;
endfunction
typedef struct {
Bit#(3) repBoundTopBits;
Bool topHi;
Bool baseHi;
Bool addrHi;
Int#(2) topCorrection;
Int#(2) baseCorrection;
} MetaInfo deriving(Bits, FShow);
function MetaInfo getMetaInfo (CapFat cap);
Bit#(3) tb = truncateLSB(cap.bounds.topBits);
Bit#(3) bb = truncateLSB(cap.bounds.baseBits);
Bit#(3) ab = truncateLSB(cap.addrBits);
Bit#(3) repBound = bb - 3'b001;
Bool topHi = tb < repBound;
Bool baseHi = bb < repBound;
Bool addrHi = ab < repBound;
Int#(2) topCorrection = (topHi == addrHi) ? 0 : ((topHi && !addrHi) ? 1 : -1);
Int#(2) baseCorrection = (baseHi == addrHi) ? 0 : ((baseHi && !addrHi) ? 1 : -1);
return MetaInfo {
repBoundTopBits: repBound,
topHi : topHi,
baseHi : baseHi,
addrHi : addrHi,
topCorrection : topCorrection,
baseCorrection : baseCorrection
};
endfunction
// ===============================================================================
// Typeclass instance for interface
typedef Bit#(TAdd#(1, CapW)) CapMem;
typedef CapFat CapReg;
typedef struct {
CapFat capFat;
TempFields tempFields;
} CapPipe deriving (Bits);
instance CHERICap #(CapMem, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
function isValidCap (x);
CapabilityInMemory capMem = unpack(x);
return capMem.isCapability;
endfunction
function setValidCap (x, v);
CapabilityInMemory capMem = unpack(x);
capMem.isCapability = v;
return pack(capMem);
endfunction
function getFlags = error("feature not implemented for this cap type");
function setFlags = error("feature not implemented for this cap type");
function getHardPerms = error("feature not implemented for this cap type");
function setHardPerms = error("feature not implemented for this cap type");
function getSoftPerms = error("feature not implemented for this cap type");
function setSoftPerms = error("feature not implemented for this cap type");
function getKind = error("feature not implemented for this cap type");
function getType = error("feature not implemented for this cap type");
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 setAddrUnsafe = error("feature not implemented for this cap type");
function getOffset = error("feature not implemented for this cap type");
function modifyOffset = error("feature not implemented for this cap type");
function getBase = error("feature not implemented for this cap type");
function getTop = error("feature not implemented for this cap type");
function getLength = error("feature not implemented for this cap type");
function isInBounds = error("feature not implemented for this cap type");
function setBounds = error("feature not implemented for this cap type");
function nullWithAddr = error("feature not implemented for this cap type");
function almightyCap = error("feature not implemented for this cap type");
function nullCap = error("feature not implemented for this cap type");
function validAsType = error("feature not implemented for this cap type");
function fromMem = error("feature not implemented for this cap type");
function toMem = error("feature not implemented for this cap type");
function maskAddr = error("feature not implemented for this cap type");
function getBaseAlignment = error("feature not implemented for this cap type");
function getRepresentableAlignmentMask = error("feature not implemented for this cap type");
function getRepresentableLength = error("feature not implemented for this cap type");
endinstance
instance FShow #(CapPipe);
function fshow(cap) = $format(
"v: ", fshow(isValidCap(cap)),
" a: ", fshow(getAddr(cap)),
" o: ", fshow(getOffset(cap)),
" b: ", fshow(getBase(cap)),
" t: ", fshow(getTop(cap)),
" sp: ", fshow(pack(getSoftPerms(cap))),
" hp: ", fshow(pack(getHardPerms(cap))),
" ot: ", fshow(getType(cap)),
" f: ", fshow(getFlags(cap)));
endinstance
instance CHERICap #(CapReg, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
function isValidCap (x) = x.isCapability;
function CapReg setValidCap (CapReg cap, Bool tag);
cap.isCapability = tag;
return cap;
endfunction
function getFlags (cap) = cap.flags;
function setFlags (cap, flags);
cap.flags = flags;
return cap;
endfunction
function HardPerms getHardPerms (CapReg cap);
return HardPerms {
permitSetCID: cap.perms.hard.permit_set_CID,
accessSysRegs: cap.perms.hard.access_sys_regs,
permitUnseal: cap.perms.hard.permit_unseal,
permitCCall: cap.perms.hard.permit_ccall,
permitSeal: cap.perms.hard.permit_seal,
permitStoreLocalCap: cap.perms.hard.permit_store_ephemeral_cap,
permitStoreCap: cap.perms.hard.permit_store_cap,
permitLoadCap: cap.perms.hard.permit_load_cap,
permitStore: cap.perms.hard.permit_store,
permitLoad: cap.perms.hard.permit_load,
permitExecute: cap.perms.hard.permit_execute,
global: cap.perms.hard.non_ephemeral
};
endfunction
function CapReg setHardPerms (CapReg cap, HardPerms perms);
cap.perms.hard = HPerms {
permit_set_CID: perms.permitSetCID,
access_sys_regs: perms.accessSysRegs,
permit_unseal: perms.permitUnseal,
permit_ccall: perms.permitCCall,
permit_seal: perms.permitSeal,
permit_store_ephemeral_cap: perms.permitStoreLocalCap,
permit_store_cap: perms.permitStoreCap,
permit_load_cap: perms.permitLoadCap,
permit_store: perms.permitStore,
permit_load: perms.permitLoad,
permit_execute: perms.permitExecute,
non_ephemeral: perms.global
};
return cap;
endfunction
function SoftPerms getSoftPerms (CapReg cap);
return zeroExtend(cap.perms.soft);
endfunction
function CapReg setSoftPerms (CapReg cap, SoftPerms perms);
cap.perms.soft = truncate(perms);
return cap;
endfunction
function Kind getKind (CapReg cap);
case (cap.otype)
otype_unsealed: return UNSEALED;
otype_sentry: return SENTRY;
default: return (cap.otype <= otype_max) ? SEALED_WITH_TYPE : RES0;
endcase
endfunction
function getType (cap) = getTypeFat(cap).d;
function CapReg setType (CapReg cap, Bit #(OTypeW) otype);
if (otype == -1) begin
cap = unseal(cap, ?);
end else begin
cap = seal(cap, ?, VnD {v: True, d:otype});
end
return cap;
endfunction
function getAddr (cap) = truncate(getAddress(cap));
function setAddr = error("feature not implemented for this cap type");
function CapReg setAddrUnsafe (CapReg cap, Bit#(CapAddressW) address);
return setCapPointer(cap, zeroExtend(address));
endfunction
function getOffset = error("feature not implemented for this cap type");
function modifyOffset = error("feature not implemented for this cap type");
function getBase = error("feature not implemented for this cap type");
function getTop = error("feature not implemented for this cap type");
function getLength = error("feature not implemented for this cap type");
function isInBounds = error("feature not implemented for this cap type");
function Exact#(CapReg) setBounds (CapReg cap, Bit#(CapAddressW) length);
SetBoundsReturn sr = setBoundsFat(cap, length);
return Exact {exact: sr.exact, value: sr.cap};
endfunction
function CapReg nullWithAddr (Bit#(CapAddressW) addr);
CapReg res = nullCap;
res.address = zeroExtend(addr);
res.addrBits = {2'b0, truncateLSB(addr)};
return res;
endfunction
function almightyCap = defaultCapFat;
function nullCap = null_cap;
function Bool validAsType (CapReg dummy, Bit#(CapAddressW) checkType);
UInt#(CapAddressW) checkTypeUnsigned = unpack(checkType);
UInt#(CapAddressW) otypeMaxUnsigned = unpack(zeroExtend(otype_max));
return checkTypeUnsigned <= otypeMaxUnsigned;
endfunction
function fromMem (x) = cast(pack(x));
function toMem (x) = unpack(cast(x));
function CapReg maskAddr (CapReg cap, Bit#(TSub#(MW, 3)) mask);
return setCapPointer(cap, cap.address & {~0,mask});
endfunction
function Bit#(2) getBaseAlignment (CapReg cap);
// If cap exp is non-zero, we have internal exponent, so the least significant
// two bits of the base are implicitly zero.
// Otherwise, we have a zero exponent, so the least significant two bits
// of the base are the least significant bits of the encoded base
if (cap.bounds.exp == 0) return cap.bounds.baseBits[1:0];
else return 2'b0;
endfunction
function Bit#(CapAddressW) getRepresentableAlignmentMask (CapReg dummy, Bit#(CapAddressW) length_request);
SetBoundsReturn sr = setBoundsFat(nullCap, length_request);
return sr.mask;
endfunction
function Bit#(CapAddressW) getRepresentableLength (CapReg dummy, Bit#(CapAddressW) length_request);
SetBoundsReturn sr = setBoundsFat(nullCap, length_request);
return sr.length;
endfunction
endinstance
instance CHERICap #(CapPipe, OTypeW, FlagsW, CapAddressW, CapW, TSub#(MW, 3));
//Functions supported by CapReg are just passed through
function isValidCap (x) = isValidCap(x.capFat);
function setValidCap (cap, tag);
return CapPipe {capFat: setValidCap(cap.capFat, tag), tempFields: cap.tempFields};
endfunction
function getFlags (cap) = getFlags(cap.capFat);
function setFlags (cap, flags);
return CapPipe {capFat: setFlags(cap.capFat, flags), tempFields: cap.tempFields};
endfunction
function getHardPerms (cap) = getHardPerms(cap.capFat);
function CapPipe setHardPerms (CapPipe cap, HardPerms perms);
return CapPipe {capFat: setHardPerms(cap.capFat, perms), tempFields: cap.tempFields};
endfunction
function getSoftPerms (cap) = getSoftPerms(cap.capFat);
function CapPipe setSoftPerms (CapPipe cap, SoftPerms perms);
return CapPipe {capFat: setSoftPerms(cap.capFat, perms), tempFields: cap.tempFields};
endfunction
function getKind (cap) = getKind(cap.capFat);
function getType (cap) = getType(cap.capFat);
function setType (cap, otype);
return CapPipe{capFat: setType(cap.capFat, otype), tempFields: cap.tempFields};
endfunction
function getAddr (cap) = getAddr(cap.capFat);
function CapPipe maskAddr (CapPipe cap, Bit#(TSub#(MW, 3)) mask);
return CapPipe {capFat: maskAddr(cap.capFat, mask), tempFields: cap.tempFields};
endfunction
function Bool validAsType (CapPipe dummy, Bit#(CapAddressW) checkType);
return validAsType(dummy.capFat, checkType);
endfunction
function toMem (cap) = toMem(cap.capFat);
function getBaseAlignment (cap) = getBaseAlignment(cap.capFat);
//Functions supported by CapReg but which require TempFields to be changed
function Exact#(CapPipe) setBounds (CapPipe cap, Bit#(CapAddressW) length);
let result = setBounds(cap.capFat, length);
return Exact {exact: result.exact, value: CapPipe {capFat: result.value, tempFields: getTempFields(result.value)}};
endfunction
function CapPipe nullWithAddr (Bit#(CapAddressW) addr);
CapReg res = nullWithAddr(addr);
return CapPipe {capFat: res, tempFields: getTempFields(res)};
endfunction
function fromMem (capBits);
CapReg res = fromMem(capBits);
return CapPipe {capFat: res, tempFields: getTempFields(res)};
endfunction
function almightyCap;
CapReg res = almightyCap;
return CapPipe {capFat: res, tempFields: getTempFields(res)};
endfunction
function nullCap;
CapReg res = nullCap;
return CapPipe {capFat: res, tempFields: getTempFields(res)};
endfunction
//Functions that require TempFields
function Exact#(CapPipe) setAddr (CapPipe cap, Bit#(CapAddressW) address);
let result = setAddress(cap.capFat, zeroExtend(address), cap.tempFields);
cap.capFat = result.d;
cap.tempFields = getTempFields(cap.capFat);
return Exact {exact: result.v, value: cap};
endfunction
function CapPipe setAddrUnsafe (CapPipe cap, Bit#(CapAddressW) address);
cap.capFat = setAddrUnsafe(cap.capFat, address);
cap.tempFields = getTempFields(cap.capFat);
return cap;
endfunction
function getOffset (x) = getOffsetFat(x.capFat, x.tempFields);
function Exact#(CapPipe) modifyOffset (CapPipe cap, Bit#(CapAddressW) offset, Bool doInc);
let result = incOffsetFat(cap.capFat, pack(cap.capFat.address) + zeroExtend(offset), zeroExtend(offset), cap.tempFields, !doInc);
cap.capFat = result.d;
cap.tempFields = getTempFields(cap.capFat);
return Exact {exact: result.v, value: cap};
endfunction
function Bit#(CapAddressW) getBase (CapPipe cap);
return truncate(getBotFat(cap.capFat, cap.tempFields));
endfunction
function Bit#(TAdd#(CapAddressW,1)) getTop (CapPipe cap);
return truncate(getTopFat(cap.capFat, cap.tempFields));
endfunction
function Bit#(TAdd#(CapAddressW,1)) getLength (CapPipe cap);
return truncate(getLengthFat(cap.capFat, cap.tempFields));
endfunction
function Bool isInBounds (CapPipe cap, Bool inclusive);
return capInBounds(cap.capFat, cap.tempFields, inclusive);
endfunction
function getRepresentableAlignmentMask (dummy) = getRepresentableAlignmentMask(null_cap);
function getRepresentableLength (dummy) = getRepresentableLength(null_cap);
endinstance
instance Cast#(CapMem, CapReg);
function CapReg cast (CapMem thin);
return unpackCap(thin ^ packCap(null_cap));
endfunction
endinstance
instance Cast#(CapReg, CapMem);
function CapMem cast (CapReg fat);
return packCap(fat) ^ packCap(null_cap);
endfunction
endinstance
instance Cast#(CapReg, CapPipe);
function CapPipe cast (CapReg thin);
return CapPipe { capFat: thin, tempFields: getTempFields(thin) };
endfunction
endinstance
instance Cast#(CapPipe, CapReg);
function CapReg cast (CapPipe fat);
return fat.capFat;
endfunction
endinstance
instance Cast#(function CapReg f0(t x), function CapPipe f1(t y));
function cast(f0);
function CapPipe f1(t arg) = cast(f0(arg));
return f1;
endfunction
endinstance
instance Cast#(function CapPipe f0(t y), function Bit#(64) f1(t x));
function cast(f0);
function Bit#(64) f1(t arg) = getAddr(f0(arg));
return f1;
endfunction
endinstance
endpackage
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