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COATCheck

COATCheck is a methodology and automated tool for verifying that a particular microarchitecture correctly implements the memory consistency model defined by the architectural specification.

COATCheck is derived from PipeCheck and CCICheck. Much of the terminology and naming comes from those tools. See those papers/websites for details.

http://github.com/daniellustig/pipecheck

http://github.com/ymanerka/ccicheck

Citing COATCheck

If you use our tool in your work, we would appreciate it if you cite our paper(s):

Daniel Lustig, Michael Pellauer, and Margaret Martonosi. "PipeCheck: Specifying and Verifying Microarchitectural Enforcement of Memory Consistency Models", 47th International Symposium on Microarchitecture (MICRO), Cambridge UK, December 2014.

Yatin Manerkar, Daniel Lustig, Michael Pellauer, and Margaret Martonsi. "CCICheck: Using uhb Graphs to Verify the Coherence-Consistency Interface", 48th International Symposium on Microarchitecture (MICRO), Honolulu, HI, December 2015.

Daniel Lustig+, Geet Sethi+, Margaret Martonosi, and Abhishek Bhattacharjee. "COATCheck: Verifying Memory Ordering at the Hardware-OS Interface", 21st International Conference on Architectural Support for Programming Languages and Operating Systems (ASPLOS), Atlanta, GA, April 2016. (+: joint first authors)

Contacting the authors

If you have any comments, questions, or feedback, please contact Daniel Lustig at [email protected], or visit our GitHub page, github.com/daniellustig/coatcheck.

Status

At this point, COATCheck is a research tool rather than an industry-strength verification toolchain. We do appreciate any suggestions or feedback either in approach or in implementation. If you are interested in any particular feature, missing item, or implementation detail, please contact the authors and we will try to help out as best we can.

Building and Using COATCheck

Prerequisites

COATCheck is written in Coq and extracted to OCaml for compilation to a native executable. COATCheck requires Coq (v4.0 or later) and OCaml (tested on version 8.4pl5). The authors have compiled and executed COATCheck successfully on both Linux and Mac.

• Coq
  • tested with Coq 8.4pl5 (October 2014)
• OCaml
  • tested with OCaml 4.01.0
• neato, part of GraphViz (only for visualization)
  • tested with 2.36.0 (20140111.2315)
• herd, part of diy (http://diy.inria.fr/herd)
  • tested with herd 5.99-D (as part of diy-5.99-D)

(all of the above tested on a Mac with Yosemite)

Building

1. make
2. (optional, can be slow) make web

Usage

Basic Usage:

./src/pipecheck -i <litmus test> -m <uspec model> [-o <generated neato graph>]

For more options, just run pipecheck by itself to see the list of available flags.

Sample Usage

1. mkdir graphs
2. ./src/pipecheck -i tests/x86tso/sb.test -m uarches/FiveStage.uarch -o graphs/sb.gv
3. neato -Tpdf graphs/sb.gv -o graphs/sb.pdf

Design Approach

COATCheck is written in Coq, a theorem prover/verification assistant. For example, Coq has been used to rigorously and formally verify mathematical theorems such as the four color theorem, and it has been used to produce C compilers which provably produce correct C code. COATCheck itself does not yet contain any verified theorems or processes. Nevertheless, we chose Coq to make for easier integration with other formal models written using Coq, and to leave open the possiblity of making COATCheck more rigorous in the future.

In practice, we are also interested in using COATCheck as a practical tool. For this reason, we auto-extract our code from Coq to OCaml (using built-in Coq methodology for doing so), and we compile this code to run natively. So far, we have not put much effort into optimizing for performance of this code, partially because of COATCheck's current status as a research tool, but more importantly because we haven't yet found performance to be a bottleneck. All of COATCheck's tests run within a few minutes even without special optimization effort, and so optimization at this point would likely be premature anyway.

FAQ

For building the web interface:

Q: ocamlfind: Package js_of_ocaml.syntax' not found A: If js_of_ocaml was installed using opam, try: eval opam config env`

Q: I get a bunch of warnings like the following: File "Process.ml", line 39, characters 4-122: Warning 21: this statement never returns (or has an unsound type.) A: This is expected behavior within the way we are using js_of_ocaml