An experimental UEFI bootloader for the Linux kernel written in Rust.
Unlike other UEFI-only bootloaders, Bread does not use the kernel UEFI-stub. Instead, it relies on the same boot protocol that has been used in traditional BIOS booting for years. This allows for greater control over the memory map and enables more advanced boot scenarios, such as secure boot and encryption, without requiring special support from the kernel.
Currently, the following architectures are supported:
- x86-64
- aarch64
In the future, riscv64gc will also be a target, but currently, there are no actual UEFI riscv boards available.
Before building Bread, there are a few prerequisites:
- just must be installed and available in the PATH.
- Rust must be installed via rustup. Distro-provided rust versions will not work.
- QEMU can be optionally installed to run the bootloader in a VM.
To build Bread, simply run just in the terminal. You can then copy the
resulting bread.efi file to your EFI partition.
To run inside a vm, ensure QEMU is available in the PATH, then run:
just qemu-x86_64 # or qemu-aarch64
This will create a new ESP folder containing the required files and launch QEMU
using the scripts located in the scripts folder.
TODO
To interact with the UEFI system, Bread uses a custom library called effie,
which can be found in the corresponding folder. While effie might seem like a
general-purpose UEFI library, its scope is much narrower and is tailored to the
specific needs of this project. For this reason, most protocols are not
implemented unless absolutely required. Nevertheless, this library can be used
standalone to write UEFI programs. If you need a protocol to be implemented,
feel free to open a PR.
This project is licensed under the APACHE-2.0 LICENSE. You can find more info in the LICENSE file.