Why can target aarch64-unknown-freebsdnot be installed?
me@debian:~/dev/proxy-server$ rustup target add aarch64-unknown-freebsd
error: toolchain 'stable-x86_64-unknown-linux-gnu' does not support target 'aarch64-unknown-freebsd'
note: you can see a list of supported targets with `rustc --print=target-list`
When I run rustc --print=target-list, as suggested, it does show up as supported
Note that x86_64-unknown-freebsd and i686-unknown-freebsd install just fine!
At the moment, I can successfully cross-compile from Linux to x86_64-unknown-freebsd and i686-unknown-freebsd as well as aarch64-apple-darwin and x86_64-apple-darwin. It would be very cool, if x86_64-unknown-freebsd could somehow be made working too
My system info:
me@debian:~/dev/proxy-server$ cargo version
cargo 1.85.0 (d73d2caf9 2024-12-31)
me@debian:~/dev/proxy-server$ uname -a
Linux debian 6.12.16-amd64 #1 SMP PREEMPT_DYNAMIC Debian 6.12.16-1 (2025-02-22) x86_64 GNU/Linux
Rust's own infrastructure only produces builds for Tier 1 and 2 platforms. For Tier 3 like aarch64-unknown-freebsd, the code is there but you have to build it yourself, including the standard library.
What is the rationale to make i686, which is pretty much an obsolete architecture (everybody who uses "x86" processor today almost certainly uses x86_64), a "Tier 2" platform, but make aarch64, which everybody seems to be moving to right now, only a "Tier 3" platform
If I were to build aarch64-unknown-freebsd myself, how complicated is that? Can it be cross-compiled on a Linux (x64) machine, or do I need a "native" FreeBSD running on aarch64?
I would guess that's just historical momentum. We have Tier 1 aarch64 Linux and macOS targets, and we're starting to demote some i686 targets. I suppose nobody has bothered to figure out how to get aarch64-unknown-freebsd building in Rust CI yet. There's also a more specific page where you can find the current maintainers, and maybe even join them:
In general, you can use the nightly toolchain with Cargo's -Zbuild-std option, but you'll still have to get the C toolchain for cross-compilation. Maybe Debian has that target already? The script in Rust CI is here:
