How to compile post-01 on macOS ARM (Apple Silicon)

[arthasyou]

Hi Philipp,

First, thank you so much for the excellent OS development series. I'm currently following the post-01 branch of blog_os, and wanted to report the steps required to successfully build the project on Apple Silicon Macs (ARM64).

Since this platform is increasingly popular among Rust developers, I believe this could help others avoid common pitfalls and build failures.

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✅ Environment

• macOS 14.x (ARM64 / Apple Silicon)
• Homebrew-installed llvm and ld.lld
• Rust nightly (rustup update nightly)
• Using cargo build -Z build-std

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🔧 Required Steps for post-01 on macOS ARM

1. Install prerequisites:

rustup update nightly
rustup component add rust-src --toolchain nightly
brew install llvm

2. Create target file aarch64-blog_os.json:

{
  "llvm-target": "aarch64-unknown-none",
  "target-endian": "little",
  "target-pointer-width": "64",
  "arch": "aarch64",
  "os": "none",
  "vendor": "unknown",
  "linker-flavor": "ld.lld",
  "linker": "/opt/homebrew/opt/llvm/bin/ld.lld",
  "panic-strategy": "abort",
  "disable-redzone": true,
  "features": "+strict-align",
  "executables": true
}

⚠️ Do NOT include data-layout, or you'll hit a mismatch error when building core with -Z build-std.

3. Use this command to build:

cargo +nightly build -Z build-std=core --target aarch64-blog_os.json

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💡 Suggestion

Would you consider adding a section in the README or a separate guide for macOS ARM builds? I’d be happy to contribute a PR if that’s helpful.

Thanks again for the awesome tutorials!

[bjorn3]

Just building for an arm64 target doesn't work. Blog OS is fundamentally an x86_64 OS. There are significant differences between the essential interfaces x86_64 and arm64 expose to the kernel. If you want to work through Blog OS on arm64, you should compile for x86_64 and then run it in an x86_64 VM using something like qemu. This will be slower than a native arm64 VM, but at least it works and Blog OS doesn't do anything heavy anyway, so you won't notice the slowdown.