Making a RISC-V Operating System Using Rust

http://web.eecs.utk.edu/~smarz1/osblog/

by fogus • 7 years ago

300 46 7 years ago

web.eecs.utk.edu

tomlong• 7 years ago

I see the author and I share a naming convention for our miscellaneous scripts, and `do.sh` appears prominently in both our work.

I subsequently branched out to e.g. `do-backups.sh`, where despite the `do-` being superfluous, I quite like the aesthetic.

Slightly more on topic: I really enjoy blog series like these, with plenty of detail on esoteric topics I really have no idea about, or on the face of it much interest in. They're a fun way to increase the breadth of topics I have a superficial knowledge of.

azhenley4• 7 years ago

I've been pushing the author to write this up for a year now (we both work at University of Tennessee). He teaches a lot of OS-oriented courses and makes them for fun so he is perfect to write this.

Next I'm trying to convince him to make an OS in Zig for Raspberry Pi with a focus on graphics. If you have any suggestions for him, shoot him an email!

jermaustin1• 7 years ago

What would a "focus on graphics" mean? A GUI and windowing system, or just graphics processing?

azhenley4• 7 years ago

I want it to be a video game console :) I think our students would have a lot of fun with that.

monocasa2• 7 years ago

On a related note, MIT seems to have ported xv6 to riscv.

https://github.com/mit-pdos/xv6-riscv

Lichtso• 7 years ago

Looks similar to my effort to interface RISC-V emulators and bare metal C: https://github.com/Lichtso/riscv-llvm-templates

GRBurst2• 7 years ago

I really really like the first sentence

RISC-V ("risk five") and the Rust programming language both start with an R, so naturally they fit together

agumonkey• 7 years ago

I expect the os to be fully based around and r7rs loaded racket erlang and R.

phkahler• 7 years ago

"Because I wanted to" should be reason enough. But for those who demand a better justification, this is very specific ;-)

DannyB22• 7 years ago

When RISC-V inevitably renames itself CISC-V, then what language would naturally fit together?

And don't say cobol.

antoinealb• 7 years ago

C++?

kbenson• 7 years ago

Why nor CRISC-V? Or CaRISC-V? Or (eww) RaCISC-V?

It's not like current "CISC" architectures haven't taken a lot of the good aspects of RISC already too...

gpm• 7 years ago

Cython with a rust core?

mindcrime• 7 years ago

Ceylon?[1]

Crystal?[2]

Church?[3]

Coq?[4]

[1] https://ceylon-lang.org/

[2] https://crystal-lang.org/

[3] https://en.wikipedia.org/wiki/Church_(programming_language)

[4] https://en.wikipedia.org/wiki/Coq

Someone• 7 years ago

COMTRAN would be a way better choice than COBOL :-) (https://en.wikipedia.org/wiki/COMTRAN)

Common Lisp would be a decent choice, too, with

    CISC:RISC = Common Lisp:Scheme

madmulita• 7 years ago

Obviously: Clojure.

astrobe_• 7 years ago

Well it would be "less risk", maybe even "riskless" so I guess you'd need a new language named "restless"?

swsieber• 7 years ago

https://vlang.io/

You could vlog about it.

pnako• 7 years ago

Worse is better, forever.

GRBurst2• 7 years ago

Since there are missing parts: Do you have a sheduling plan for the remaining posts?

azhenley4• 7 years ago

One per week.

coldnose• 7 years ago

Rust is build around the expectation that allocations happen automatically and can never fail. I’m curious to see how they deal with this in a kernel...

steveklabnik• 7 years ago

Rust, the language, strictly speaking, knows nothing about allocation at all.

The standard library assumes infallible allocation currently. Kernels generally do not use the standard library.

(Okay, STRICTLY speaking there’s a hack for Box<T> in the language right now but it’s not about the allocation part and Box<T> is technically defined in the standard library with Magic(tm) and so isn’t relevant in an OS dev context, as you won’t use the standard library and therefore Box<T>. Rust-the-language never implicitly inserts heap allocations, including Box<T>, anywhere.)

SAI_Peregrinus• 7 years ago

The Rust standard library is. The Rust Core library (the far more minimal library that gets used when you mark a crate as #![no_std]) does not. That's how the other "OS in Rust" and "allocator in Rust" projects work.

wahern2• 7 years ago

Well, this OS in Rust project simply commits the same sins as the standard library by using a custom allocation routine that panics on allocation failure: https://os.phil-opp.com/heap-allocation/#allocations-in-rust

Saying that Rust the language doesn't require a non-failing allocator misses the point--the ergonomics of the language make dealing with allocation failure difficult; sufficiently difficult that none of the projects I've seen actually bother attempting it.

See https://cs.brown.edu/research/pubs/theses/ugrad/2015/light.a..., which explains idiomatic Rust instructs developers to return by value, relying on caller assignment to types like Box (which uses exchange_malloc under the hood), to handle heap allocation. Basically, the strategy for dynamic object management in Rust is predicated on hidden heap allocations.

So of course it's not necessary. But good luck writing an entire operating system otherwise. Even Redox OS doesn't bother trying to fight the language in this regard: https://gitlab.redox-os.org/redox-os/slab_allocator/blob/mas...

tal8d• 7 years ago

Try harder: https://doc.rust-lang.org/std/alloc/trait.GlobalAlloc.html#t...

You can implement your own global allocator, use an existing crate, or (in the case of user applications) use the system's. That is for the stdlib level, not even core...

muricula• 7 years ago

Nope, the GP is still correct. If your custom allocator fails, anything created with Box::new or similar will panic.

Rusky• 7 years ago

You deal with this in a Rust kernel in exactly the same way you deal with it in a C kernel: by using different APIs for allocation.

Linux doesn't use malloc; a Rust kernel need not use Box::new either.

loquor• 7 years ago

For someone with a standard CS undergraduate education, how much effort (in hrs/week) would such an endeavour require?

DannyB22• 7 years ago

Old wives tail from ancient times, before CompuServe:

The first 20% of the effort gets you about 80% of the results. So everything seems exciting. But to that that last 20% of the results requires 80% of the total work.

There is a ton of un-fun, un-glamorous work getting a gazillion device drivers written, for example.

nickpsecurity2• 7 years ago

You can always use a hypervisor, a driver OS that re-uses Windows/Linux drivers, and the new OS in a VM using virtual drivers. That's what some L4-based setups, including commercial OKL4, did. They also let you write native drivers directly on the microkernel or in OS VM's for situations where effort was justified. I'm surprised more haven't done this.

Rump kernels are the closest trend.

duckqlz• 7 years ago

Wow! What an awesome tutorial/book. I look forward to reading more chapters. This is already an extremely useful resource since it covers cross compilation from an x86 system. I love to play around with this kind of stuff in my free time but connecting to dev boards and constantly shifting paradigms was annoying enough to limit my enthusiasm. It took a lot of research to find out how to do what the author fits in a single chapter. Thank you for this awesome post!

mastrsushi• 7 years ago

Making X.....but using Rust!!!

turblety• 7 years ago

Amazing tutorial, and really exciting for RISC-V. I hope he creates a patreon or some other donation platform, as it must take some time to write this up. I'm sure some people would be willing to send a bit his way.

azhenley4• 7 years ago

Done! Thanks for the suggestion. The Patreon link is at the top of the blog.

etskinner• 7 years ago

One suggestion: Your patreon page only mentions the Aarch64 project, not the Rust on RISC-V project. That might alienate people coming from the Rust blog; they might think they landed in the wrong spot (I sure did)

ashort11• 7 years ago

I took Programing Languages from him, as well as TA'd for his Operating Systems class. He is an amazing lecturer, and I am glad he is releasing something like this to the public! Definitely something worthwhile to read. Looking forward to more content being released.

Making a RISC-V Operating System Using Rust

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