kerla

How does this compare to https://github.com/nuta/kerla ?

There was also the similar project Kerla¹ but development stalled. Recently people argued that instead of focusing on Rust-for-Linux it would be easier to create a drop-in replacement like these two. I wonder if there are enough people interested to make this happen as a sustained project. ¹ https://github.com/nuta/kerla/

I think this had already been attempted by the now-discontinued project [Kerla](https://github.com/nuta/kerla).

> [..] in kernel mode while retaining the ability to compare how the very same usermode bits run on the Linux kernel as well. That's a unique feature in the realm of educational kernels. There's also Kerla: https://github.com/nuta/kerla

> How would that work in reality? Re-use the existing tests to build a new kernel from scratch? Sounds like a very far-out idea that wouldn't help with any of the current problems, but I'm happy to entertain the idea and hear your reasoning here. While I would tend to agree that a full production replacement would be such a massive undertaking as to be impractical, https://github.com/nuta/kerla does something very like that - Linux userspace ABI on an all-new Rust kernel. (And even at this small scale, I find it mind-blowing that this worked)

> panicking = crashing the computer That isn't very accurate. In Rust when programming in no_std, you can (must?) define your own panic handler: https://doc.rust-lang.org/nomicon/panic-handler.html Which you would define in the kernel. While I'm not going to speculate on exactly what the implementation would look like, you definitely do not need to "crash" the computer. I haven't done any kernel programming, but I'm guessing the kernel could do some things at that point with shared memory space that is already allocated to deal with this situation and try to recover in some way. Edit: for example, I just found this in the kerla project: https://github.com/nuta/kerla/blob/88fd40823852a63bd639e602b... That halts now, but it probably doesn't need to, or could do it conditionally based on the contents of PanicInfo.

Author here. I'm surprised to see my hobby project on Hacker News. I know this kind of stuff spark the ``it's meaningless to rewrite everything (especially Linux) in Rust'' debate. I agree 100% that rewriting Linux in Rust (or your favorite language) is just a waste of time and such a project won't live long. That said, what I'd say here is that it's fun. Really fun. Implementing ABI compatibility requires you to understand under the hood of the kernel. You can learn how printf(3) works. You can learn what happens before main(). Especially, in Rust, it's inspiring to explore ways to write a kernel safely and expressively. One of my favorite part is the implementation of read system call [1]. Lastly, You can try this OS on SSH. Hope you enjoy :) ssh root@kerla-demo.seiya.me [1]: https://github.com/nuta/kerla/blob/main/kernel/syscalls/