Cross-compiling

The Pinephone’s triple for cross-compiling is aarch64-unknown-linux-gnu.

C/++

Installing the Toolchain

First, you’ll need to install the gcc cross-compilation toolchain.

On Arch Linux

$ sudo pacman -S aarch64-linux-gnu-gcc

On Ubuntu/Debian

$ sudo apt install gcc-aarch64-linux-gnu

On Void Linux

$ sudo xbps-install cross-aarch64-linux-gnu

Using the Toolchain

GNU Make

Kernel Makefile

For each invocation of make, be sure to pass the options ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- like this:

$ make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-

Other

If you are using a handwritten Makefile (not autogenerated by a meta-buildsystem such as meson, automake, etc.) then simply override CC and LD as you need.

automake

$ ./configure --host=aarch64-linux-gnu

meson

See the official meson documentation on the topic. In general, the introduction is a good read for any cross-compiling novice.

Rust

In order to cross-compile Rust applications for the Pinephone, you need to have a gcc cross-compiler installed and the Rust dependencies, usually the std crate, cross compiled for the target system. A more extensive explanation can be found on https://github.com/japaric/rust-cross. This instruction is based on it’s description.

Installing a GCC Cross-Compiler

The cross-compiler might have a different name depending on the operating system. Further along this instruction the name for the gcc cross-compiler will be used. Replace all occurences of $gcc_name with the name on your distribution.

For how to install the gcc cross-compilation toolchain on your distribution, please see Cross-compiling

Installing Rust Dependencies

The necessary dependencies can easily be installed with rustup:

$ rustup target add aarch64-unknown-linux-gnu

OR it can be installed with multirust [Is this still accurate???]:

$ multirust add-target nightly aarch64-unknown-linux-gnu

Compiling

rustc

When using rustc just add the two flags –target=aarch64-unknown-linux-gnu and -C linker=$gcc_name. Under Arch, this would look like:

$ rustc --target=aarch64-unknown-linux-gnu -C linker=aarch64-linux-gnu-gcc main.rs

To test it, run the program on your Pinephone

$ scp main user@ipadress:/home/user/Downloads
$ ssh user@ipadress /home/user/Downloads/main
Hello, world!

cargo

To cross-compile a project with cargo, open the folder of the project in a terminal. Then create a new folder and a file for cargo.

$ mkdir .cargo
$ cat >.cargo/config <<EOF
> [target.aarch64-unknown-linux-gnu]
> linker = "$gcc_name"
> EOF

Then you can compile it with

$ cargo build --target=aarch64-unknown-linux-gnu

To test it, copy the file on your Pinephone

$ scp target/aarch64-unknown-linux-gnu/debug/main user@ipadress:/home/user/Downloads

Then you can execute it by

$ ssh user@ipadress ./main -h
Hello, world!

Possible Errors

If you encounter an error saying

Cross compilation detected. Use PKG_CONFIG_ALLOW_CROSS=1 to override

just add that variable in front of your command e.g.

PKG_CONFIG_ALLOW_CROSS=1 cargo build --target=aarch64-unknown-linux-gnu