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Asterinas: OS kernel written in Rust and providing Linux-compatible ABI

(github.com)
364 points Klasiaster | 2 comments | 15 Oct 24 12:01 UTC | HN request time: 0.432s | source
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exabrial ◴[16 Oct 24 00:05 UTC] No.41854339[source]▶
I think this looks incredible. Like how does one create a compatible abi _for all of linux_??? Wow!

> utilize the more productive Rust programming language

Nitpick: it’s 2024 and these ‘more productive’ comparisons are silly, completely unscientific, And a bit of a red flag for your project: The most productive language for a developer is the one they understand what is happening one layer below the level of abstraction they are working with. Unless you’re comparing something rating Ruby vs RiscV assembly, it’s just hocus-pocus.

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1. kelnos ◴[16 Oct 24 03:02 UTC] No.41855189[source]▶
> Like how does one create a compatible abi _for all of linux_???

You look at Linux's syscall table[0], read through the documentation to figure out the arguments, data types, flags, return values, etc., and then implement that in your kernel. The Linux ABI is just its "library" interface to userspace.

It's probably not that difficult; writing the rest of the kernel itself is more challenging, and, frankly, more interesting. Certainly matching behavior and semantics can be tricky sometimes, I'm sure. And I wouldn't be surprised if the initial implementation of some things (like io_uring, for example, if it's even supported yet) might be primitive and poorly optimized, or might even use other syscalls to do their work.

But it's doable. While Linux's internal ABI is unstable, the syscall interface is sacred. One of Torvalds' golden rules is you don't break userspace.

[0] https://filippo.io/linux-syscall-table/

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2. JoshTriplett ◴[16 Oct 24 14:13 UTC] No.41859243[source]▶
> You look at Linux's syscall table[0], read through the documentation to figure out the arguments, data types, flags, return values, etc., and then implement that in your kernel.

As well as some subset of the files expected in /dev, /proc, /sys, and similar, which are also part of the userspace ABI. And the startup mechanisms for processes, and the layout of AUXV...

It's absolutely doable, but the interface is wider than just the syscall layer.