Add cross-compilation for installer images (small, targeted change)#192
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Add cross-compilation for installer images (small, targeted change)#192randomizedcoder wants to merge 1 commit into
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…ation)
Before this, building the installer images on a non-ARM machine (like
x86_64) needed binfmt/QEMU emulation, because the images are aarch64.
This adds cross-compilation, so you can build them on x86_64 directly.
• flake: add `installerImagesCross.{rpi02,rpi3,rpi4,rpi5}` outputs and
matching `rpiN-installer-cross` nixosConfigurations. They build on
x86_64-linux and target aarch64.
• flake: `mkNixOSRPiInstaller` now takes a `buildPlatform` argument.
When set, it sets `nixpkgs.buildPlatform` to turn on cross-compilation.
• nixpkgs-rpi: `pkgs.rpi` now keeps the build/host platform split. Before
it always used the host system, so it was built natively and needed
emulation. Now it is cross-compiled too when build != host.
• The native `installerImages.*` outputs do not change.
• README: add a "Quick start" section and document the cross build commands.
Tested: cross-built rpi4 and rpi5 images on x86_64-linux with no
emulation.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
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G'day @nvmd! 👋
This is a much smaller, more targeted follow-up to #163.
That PR was large and bundled the cross-compilation work together with a big kernel/firmware refactor. I understand that is a lot to review at once. So this PR does only one thing: it adds cross-compilation for the installer SD images. This is the main feature we want and need — building the aarch64 images on an x86_64 machine without binfmt/QEMU emulation.
It is built on top of the current
develop, so no refactor is included.What this PR does
installerImagesCross.{rpi02,rpi3,rpi4,rpi5}outputs and matchingrpiN-installer-crossnixosConfigurations. They build onx86_64-linuxand targetaarch64-linux.mkNixOSRPiInstallernow takes abuildPlatformargument. When it is set, the builder setsnixpkgs.buildPlatform, which turns on cross-compilation.pkgs.rpinow keeps the build/host platform split. Before, it always used the host system, so it was built natively and needed emulation. Now it is cross-compiled too when build != host.installerImages.*outputs do not change.How to build
Native (on an ARM machine), same as before:
nix build .#installerImages.rpi5 # or .rpi4Cross (on x86_64, no emulation), new:
nix build .#installerImagesCross.rpi5 # or .rpi4Testing
Cross-built the rpi4 and rpi5 installer images on
x86_64-linuxwith no emulation. The build compiles its ownaarch64-unknown-linux-gnutoolchain, which confirms it is really cross-compiling.Note: cross-compiled artifacts are not in the binary cache, so the first build compiles the kernel and many packages from source.
If you would prefer a different name for the outputs, or a different way to turn on cross-compilation, happy to change it. 🙂
Thanks again for the great repo, and for all the recent improvements — it is much appreciated!
🤖 Generated with Claude Code