> Rust, which has been cited as a cause for concern around ensuring continuing support for old architectures, supports 14 of the kernel's 20-ish architectures, the exceptions being Alpha, Nios II, OpenRISC, PARISC, and SuperH.
> supports 14 of the kernel's 20-ish architectures
That's a lot better than I expected to be honest, I was thinking maybe Rust supported 6-7 architectures in total, but seems Rust already has pretty wide support. If you start considering all tiers, the scope of support seems enormous: https://doc.rust-lang.org/nightly/rustc/platform-support.htm...
LLVM platform support is neither sufficient (rustc needs to be taught about the platform) not technically necessary (you could write a rustc backend that targets a platform that LLVM doesn't, like modifying cranelift or once the gcc backend reaches maturity).
Itanium was mainly dropped because it was impeding work in the EFI subsystem. EFI was originally developed for Itanium before being ported to other platforms, so the EFI maintainers had to build and test their changes to shared code on Itanium. They eventually decided that this wasn't worth the effort when there was basically nobody running modern Linux on Itanium besides a few hobbyists. I imagine that alpha and hppa will get dropped in the future if they ever also create an undue maintenance burden. There's more context here if you're interested: https://lwn.net/Articles/950466/
> Rust, which has been cited as a cause for concern around ensuring continuing support for old architectures, supports 14 of the kernel's 20-ish architectures, the exceptions being Alpha, Nios II, OpenRISC, PARISC, and SuperH.