59 lines
2.1 KiB
Plaintext
59 lines
2.1 KiB
Plaintext
: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 should easily be able to comply with the CHERI CAP LIB API.
|
|
In particular, implementations exploring alterations to the underlying
|
|
capability format will benefit from adhering to this API for easy integration
|
|
with codebases already making use of the exisitng CHERI capability implementation.
|
|
If some genuinely new behaviour is necessary, generalising the CHERI CAP API should
|
|
be considered.
|
|
|
|
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:
|
|
|
|
== The CHERI CAP LIB API
|
|
|
|
include::CHERI_CAP_API.adoc[]
|