bztsrc--bootboot/aarch64-cb

BOOTBOOT Coreboot ARM64 Implementation

See BOOTBOOT Protocol for common details.

Implements the BOOTBOOT Protocol as a coreboot payload. Currently EXPERIMENTAL. Must be compiled using the coreboot build environment.

Compilation

Step 1 - Install dependencies

First, install the coreboot dependencies: bison, build-essentials, curl, flex, git, gnat, libncurses5-dev, m4, zlib. Please refer to the linked doc for up-to-date list of dependencies.

Step 2 - Get coreboot

Download coreboot and its submodules

$ git clone https://review.coreboot.org/coreboot
$ cd coreboot
$ git submodule update --init

It is very important to initialize submodules, otherwise you won't be able to compile coreboot.

Step 3 - Create toolchain

This step could take a while. Replace $(nproc) with the number of CPU cores you have.

$ make crossgcc-aarch64 CPUS=$(nproc)

Step 4 - Patch coreboot and configure

Copy and overwrite files from ../coreboot directory to the coreboot working directory. This will update the coreboot configuration system.

Now configure coreboot for your motherboard (or qemu) and BOOTBOOT.

$ make menuconfig
    select 'Mainboard' menu
    Beside 'Mainboard vendor' should be '(Emulation)'
    Beside 'Mainboard model' should be 'QEMU AArch64'
    select 'Exit'
    select 'Devices' menu
    select 'Display' menu
    Beside 'Framebuffer mode' should be 'Linear "high-resolution" framebuffer'
    select 'Exit'
    select 'Exit'
    select 'Payload' menu
    select 'Add a Payload'
    choose 'BOOTBOOT'
    select 'Exit'
    select 'Exit'
    select 'Yes'

It is important to set the display to "linear framebuffer", because BOOTBOOT does not handle the legacy, non-portable VGA text mode. Sadly there's no way of configuring this in run-time with libpayload.

Step 5 - Build coreboot

$ make

Step 6 - Test the newly compiled ROM in QEMU

For more information, read coreboot docs.

$ qemu-system-aarch64 -bios build/coreboot.rom -M virt,secure=on,virtualization=on -cpu cortex-a53 -m 1024M \
    -drive file=$(BOOTBOOT)/images/disk-rpi.img,format=raw -serial stdio

Machine state

Code is running in supervisor mode, at EL1 on all cores.

Installation

Once you have compiled a coreboot ROM with the BOOTBOOT payload, you can flash the build/coreboot.rom file to your mainboard.

Limitations

• Only supports SHA-XOR-CBC, no AES