BOOTBOOT Coreboot x86_64 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-i386 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 x86 i440fx/piix4'
    select 'Exit'
    select 'Payload' menu
    select 'Add a Payload'
    choose 'BOOTBOOT'
    select 'Exit'
    select 'Exit'
    select 'Yes'

Step 5 - Build coreboot

$ make

Step 6 - Test the newly compiled ROM in QEMU

For more information, read coreboot docs.

$ qemu-system-x86_64 -bios $(COREBOOT)/build/coreboot.rom -drive file=$(BOOTBOOT)/images/disk-x86.img,format=raw -serial stdio

Machine state

IRQs masked. GDT unspecified, but valid, IDT unset. SSE, SMP enabled. Code is running in supervisor mode in ring 0 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

As it boots in protected mode, it only maps the first 4G of RAM.
The CMOS nvram does not store timezone, so always GMT+0 returned in bootboot.timezone.
Only supports SHA-XOR-CBC, no AES

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