OpenFirmware Rust environment

This is an attempt at creating a basic runtime environment much like uefi-rs.

For now this project is only targetting PowerVM/POWER environments as well as QEMU/SLOF. Compatibility with older PowerPC Macs is not a priority, although contributions that are easy to maintain are welcome.

Build instructions

To build sample bootloader payload, use the crate under the ```template`` directory.

This is configured as a cross compilation crate by default. The output binaries are required to be PPC32bit big endian. You need a working powerpc gcc compiler, you may need to tweak .cargo/config to point to the right binaries.

You also need to install the powerpc targe using rustup, as of now this create requires nightly so you need to make it default too:

$ rustup target add powerpc-unknown-linux-gnu

To create a valid build you need to use --release, debug builds will fail (not clear why yet):

$ rustup default nightly
$ cargo +nightly build --release --target powerpc-unknown-linux-gnu

Testing

You need qemu-system-ppc64le and the SLOF firmware binary, in fedora you can run it by having a disk image with a GPT partition table and a 4MB PReP partition where the binary will be written:

$ fallocate -l 2G disk.img
$ cfdisk -z disk.img
                               ┌ Select label type ───┐
                               │◼gpt◼◼◼◼◼◼◼◼◼◼◼◼◼
                               │ dos                  │
                               │ sgi                  │
                               │ sun                  │
                               └──────────────────────┘
                                    Disk: disk.img
                    Size: 2 GiB, 2147483648 bytes, 4194304 sectors
             Label: gpt, identifier: B0FB3AB0-6C25-8D49-97F1-92E9AD879852

    Device               Start          End      Sectors     Size Type
>>  disk.img1             2048        10239         8192       4M PowerPC PReP boot    
    disk.img2            10240      4194270	 4184031       2G Linux filesystem
 ┌───────────────────────────────────────────────────────────────────────────────────┐
 │Partition UUID: 91A7B5D3-6237-834E-A3F2-6D7D87CB3A57                               │
 │Partition type: PowerPC PReP boot (9E1A2D38-C612-4316-AA26-8B49521E5A8B)           │
 └───────────────────────────────────────────────────────────────────────────────────┘
  [ Delete ]  [ Resize ]  [  Quit  ]  [  Type  ]  [  Help  ]  [  Write ]  [  Dump  ]

To deploy the image we need to setup the disk image in a loopback device

$ sudo losetup -P -f disk.img
$ losetup -a
$ sudo losetup -a
/dev/loop0: [0043]:2771583 (/path/to/disk.img)
$ sudo dd if=target/powerpc-unknown-linux-gnu/release/of-rs-template of=/dev/loop0p1

And finally we need to launch QEMU:

$ qemu-system-ppc64 -M pseries-6.1 -bios /usr/share/qemu/slof.bin -drive file=disk.img

You should see a "Hello from Rust into Open Firmware" message in the emulator output.