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rephrase + typo

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Alexandre Joannou
2022-09-30 12:26:46 +01:00
committed by Alexandre Joannou
parent 49e6e07a70
commit e4826ac997
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@@ -1,55 +1,56 @@
:toc: macro
:toclevels: 4
:toc-title:
:toc-placement!:
:source-highlighter:
++++
<br/>
++++
[discrete]
= CHERI CAP LIB
++++
<br/>
++++
The https://github.com/CTSRD-CHERI/cheri-cap-lib[cheri-cap-lib] repository
provides an RTL API for CHERI capabilities, as well as a reference
implementation of it. It aims to serve as a central implementation providing
various wrappers to avoid the need for multiplicity of implementation efforts.
This is particularly desirable when considering the verification work already
spent and the overall tricky nature of the algorithms involved.
The explicit goal of CHERI CAP LIB is to provide a set of relatively low level
operation to interact with CHERI capabilities, and allow the user to abstract
away the specifics of the published
https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/2019tc-cheri-concentrate.pdf[capability format]
as much as reasonably possible. Other implementations could easily comply to the
CHERI CAP LIB API.
The CHERI CAP LIB API is here to guaranty that subtleties in capability
manipulations are handled correctly. This means that direct bit manipulation on
CHERI capabilities bypassing the provided functions can very easily lead to
nonsense capabilities. For this reason, the CHERI CAP LIB API is more in the
style of a set of accessors (java interface / haskell typeclass, etc...) rather
than a simple struct-style interface with direct field manipulation. Again, this
is deliberate and necessary to the good behaviour of capability operations.
Currently, the implementation of the API is in Bluespec System Verilog and
:toc: macro
:toclevels: 4
:toc-title:
:toc-placement!:
:source-highlighter:
++++
<br/>
++++
[discrete]
= CHERI CAP LIB
++++
<br/>
++++
The https://github.com/CTSRD-CHERI/cheri-cap-lib[cheri-cap-lib] repository
provides an RTL API for CHERI capabilities, as well as a reference
implementation of it. It aims to serve as a central implementation providing
various wrappers to avoid the need for multiplicity of implementation efforts.
This is particularly desirable when considering the verification work already
spent and the overall tricky nature of the algorithms involved.
The explicit goal of CHERI CAP LIB is to provide a set of relatively low level
operations to interact with CHERI capabilities, and allow the user to abstract
away the specifics of the published
https://www.cl.cam.ac.uk/research/security/ctsrd/pdfs/2019tc-cheri-concentrate.pdf[capability format]
and its subsequent iterations as much as reasonably possible. Other
implementations could easily comply with the CHERI CAP LIB API.
The CHERI CAP LIB API is here to guaranty that subtleties in capability
manipulations are handled correctly. This means that direct bit manipulation on
CHERI capabilities bypassing the provided functions are greatly discouraged as
they will very easily lead to nonsense capabilities. For this reason, the CHERI
CAP LIB API is more in the style of a set of accessors (java interface / haskell
typeclass, etc...) than in that of a simple struct-style interface with direct
field manipulation. Again, this is deliberate and necessary to easily enforce
well behaved capability manipulations.
Currently, the implementation of the API is in Bluespec System Verilog and
wrappers are available in Verilog and Blarney.
[discrete]
== Contents
toc::[]
:sectnums:
[discrete]
== Contents
toc::[]
:sectnums:
== The CHERI CAP LIB API
[source, bsv]
----
[source, bsv]
----
function Bool isValidCap (t cap);
function t setValidCap (t cap, Bool valid);
function Bit#(flg) getFlags (t cap);
@@ -83,5 +84,5 @@ function t almightyCap;
function t nullCap;
function Bool validAsType (t dummy, Bit#(n) checkType);
function t fromMem (Tuple2#(Bool, Bit#(mem_sz)) mem_cap);
function Tuple2#(Bool, Bit#(mem_sz)) toMem (t cap);
----
function Tuple2#(Bool, Bit#(mem_sz)) toMem (t cap);
----