seL4
Agda
seL4 | Agda | |
---|---|---|
60 | 27 | |
4,549 | 2,378 | |
1.2% | 0.6% | |
9.0 | 9.8 | |
3 days ago | 7 days ago | |
C | Haskell | |
GNU General Public License v3.0 or later | MIT License |
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seL4
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From L3 to seL4 what have we learnt in 20 years of L4 microkernels? [video]
> People like to snob Unix but the fact is: the world runs on Unix.
The world you are aware of runs on it.
> Can we really do that much better or is it just hubris?
Yes. Have a look at seL4[1] and Barrelfish too[2], even though that's no longer active. seL4 in particular is powering a lot of highly secure computing systems. There is a surprisingly large sphere outside of Unix/POSIX.
[1] https://sel4.systems/
[2] https://barrelfish.org/
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On the Costs of Syscalls
There are also RTOS-capable microkernels such as seL4[0], with few but extremely fast syscalls[1]. Note times are in cycles, not usec.
0. https://sel4.systems/
1. https://sel4.systems/About/Performance/
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Can the language of proof assistants be used for general purpose programming?
https://sel4.systems
Working on a number of platforms, verified on some. Multicore support is an ongoing effort afaict.
On OS built on this kernel is still subject to some assumptions (like, hardware working correctly, bootloader doing its job, etc). But mostly those assumptions are less of a problem / easier to prove than the properties of a complex software system.
As I understand it, guarantees that seL4 does provide, go well beyond anything else currently out there.
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How to write TEE/Trusted OS for ARM microcontrollers?
Take a look at this: https://sel4.systems/
- Simulation: KI-Drohne der US Air Force eliminiert Operator für Punktemaximierung
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Paragon Graphite is a Pegasus spyware clone used in the US
It's probably have to be seL4 (https://sel4.systems), running on some fully OSS hardware.
There are question marks over much of available RISC-V chips due to chinese producers, so maybe OpenPower based hardware?
Plus, the entire system (motherboard, etc) would need to be manufactured using a good supply chain.
Hmmm, this has probably all been thought through in depth before by others. :)
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Basic SAT model of x86 instructions using Z3, autogenerated from Intel docs
You can use it to (mostly) validate small snippets are the same. See Alive2 for the application of Z3/formalization of programs as SMT for that [1]. As far as I'm aware there are some problems scaling up to arbitrarily sized programs due to a lack of formalization in higher level languages in addition to computational constraints. With a lot of time and effort it can be done though [2].
1. https://github.com/AliveToolkit/alive2
2. https://sel4.systems/
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What are the current hot topics in type theory and static analysis?
Formal methods. This is not in most general-purpose programming languages and probably never will be (maybe we'll see formal methods to verify unsafe code in Rust...) because it's a ton of boilerplate (you have to help the compiler type-check your code) and also extremely complicated. However, formal methods is very important for proving code secure, such as sel4 (microkernel formally verified to not have bugs or be exploitable) which has just received the ACM Software Systems Award 3 days ago.
- Rust Now Available for Real-Time Operating System and Hypervisor PikeOS
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Amiga and AmigaOS should move to ARM.
Today we'd look at seL4.
Agda
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Types versus sets (and what about categories?)
This was recently deemed inappropriate:
"Bye bye Set"
"Set and Prop are removed as keywords"
https://github.com/agda/agda/pull/4629
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If given a list of properties/definitions and relationship between them, could a machine come up with (mostly senseless, but) true implications?
Still, there are many useful tools based on these ideas, used by programmers and mathematicians alike. What you describe sounds rather like Datalog (e.g. Soufflé Datalog), where you supply some rules and an initial fact, and the system repeatedly expands out the set of facts until nothing new can be derived. (This has to be finite, if you want to get anywhere.) In Prolog (e.g. SWI Prolog) you also supply a set of rules and facts, but instead of a fact as your starting point, you give a query containing some unknown variables, and the system tries to find an assignment of the variables that proves the query. And finally there is a rich array of theorem provers and proof assistants such as Agda, Coq, Lean, and Twelf, which can all be used to help check your reasoning or explore new ideas.
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What can Category Theory do?
Haskell and Agda are probably the most obvious examples. Ocaml too, but it is much older, so its type system is not as categorical. There is also Idris, which is not as well-known but is very cool.
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What are the current hot topics in type theory and static analysis?
Most of the proof assistants out there: Lean, Coq, Dafny, Isabelle, F*, Idris 2, and Agda. And the main concepts are dependent types, Homotopy Type Theory AKA HoTT, and Category Theory. Warning: HoTT and Category Theory are really dense, you're going to really need to research them.
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Amendmend proposal: Changed syntax for Or patterns
Does this come with plans to separately unify the body with each of the contexts induced by matching on each of the respective patterns (similar to what’s discussed here), or will it behave like the _ pattern and use only the most general context?
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Functional Programming and Maths <|> How can a code monkey learn Agda?
That's absolutely untrue. From the horse's mouth:
- Doom emacs and agda-mode
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FP language idea - would this is possible to infer and type check?
Agda has the so-called mixfix operators (which are powerful enough to cover pre/in/postfix cases with an arbitrary number of arguments), check that out: - https://agda.readthedocs.io/en/v2.6.1/language/mixfix-operators.html - https://github.com/agda/agda/blob/master/examples/Introduction/Operators.agda - https://github.com/agda/agda-stdlib/blob/master/src/Data/Product/Base.agda
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Best Programming Language for Computational Proof
Coq, Agda, Lean, Isabelle, and probably some others which are not coming to my mind at the moment, but those would be considered the major ones.
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Do you use Idris or Coq, and why?
Funny that you say this, because there are some obvious long standing open feature requests with looking up the type of the term under cursor — № 4295 and № 516. I am not blaming anyone in particular — this is the way it is. I wish I could find time to rewrite the proof search engine (how hard can it be), but I am already buried under a pile of other commitments and a good chunk of overwhelming sadness.
What are some alternatives?
l4v - seL4 specification and proofs
lean - Lean Theorem Prover
fprime - F´ - A flight software and embedded systems framework
coq - Coq is a formal proof management system. It provides a formal language to write mathematical definitions, executable algorithms and theorems together with an environment for semi-interactive development of machine-checked proofs.
nomicon - The Dark Arts of Advanced and Unsafe Rust Programming
open-typerep - Open type representations and dynamic types
CompCert - The CompCert formally-verified C compiler
HoleyMonoid - Automatically exported from code.google.com/p/monoid-cont
InitWare - The InitWare Suite of Middleware allows you to manage services and system resources as logical entities called units. Its main component is a service management ("init") system.
distributive - Dual Traversable
4.4BSD-Lite2 - 4.4BSD Lite Release 2: last Unix operating system from Berkeley
lean4 - Lean 4 programming language and theorem prover