From 3bf9c88c1d8200f17c69bddb0b7dc047e6dfc6fe Mon Sep 17 00:00:00 2001 From: Maximilian Bosch Date: Sat, 12 Oct 2024 16:41:54 +0200 Subject: [PATCH] linux_testing: enable Rust by default for aarch64-linux MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The first assumption[1] we had was that the `aarch64-unknown-none` target was missing from rustc and that this was the cause for the regression. However, it turns out that the relevant code from `rustc` wasn't used anyways because the Makefile does `--sysroot /dev/null`[2] which prevents rustc from using its own libcore. So luckily we don't have to patch the Rust bootstrap to get aarch64-linux back working[3]. In fact, the Rust part seems broken for both 6.10 and 6.11[4], but I decided to not bother since none of those are longterm versions. So all that's left here is to enable Rust for aarch64-linux because it clearly works[5]. [1] https://github.com/NixOS/nixpkgs/pull/315121#issuecomment-2135805876 [2] https://lore.kernel.org/all/20231031201752.1189213-1-mmaurer@google.com/ [3] Of course I only realized this _after_ I spent some time hacking a rustc patch together 🙃 [4] This broke with error[E0463]: can't find crate for `core` | = note: the `aarch64-unknown-none` target may not be installed = help: consider downloading the target with `rustup target add aarch64-unknown-none` = help: consider building the standard library from source with `cargo build -Zbuild-std` [5] While the build is fine, the VM tests are still panicking, but that's also the case for `kernel-generic` because of a 9p regression: switch_root: can't execute '/nix/store/zv87gw0yxfsslq0mcc35a99k54da9a4z-nixos-system-machine-test/init': Exec format error [ 1.734997] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000100 [ 1.736002] CPU: 0 UID: 0 PID: 1 Comm: switch_root Not tainted 6.12.0-rc1 #1-NixOS [...] Reported as https://lore.kernel.org/all/D4LHHUNLG79Y.12PI0X6BEHRHW@mbosch.me/T/#u --- pkgs/os-specific/linux/kernel/common-config.nix | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/pkgs/os-specific/linux/kernel/common-config.nix b/pkgs/os-specific/linux/kernel/common-config.nix index 9d024b539d83..91b57676abca 100644 --- a/pkgs/os-specific/linux/kernel/common-config.nix +++ b/pkgs/os-specific/linux/kernel/common-config.nix @@ -33,10 +33,8 @@ let kernelSupportsRust = lib.versionAtLeast version "6.7"; # Currently only enabling Rust by default on kernel 6.12+, - # which actually has features that use Rust that we want, - # and only on x86_64, because of a nixpkgs rustc issue: - # https://github.com/NixOS/nixpkgs/pull/315121#issuecomment-2135805876 - defaultRust = lib.versionAtLeast version "6.12" && stdenv.hostPlatform.isx86_64; + # which actually has features that use Rust that we want. + defaultRust = lib.versionAtLeast version "6.12" && (stdenv.hostPlatform.isx86_64 || stdenv.hostPlatform.isAarch64); withRust = (forceRust || defaultRust) && kernelSupportsRust; options = {