A Specification Is Being Discussed For Passing Firmware/Bootloader Logs To The OS
Stemming from a GRUB bootloader inquiry and discussion that started over one year ago, a new specification is being proposed for possible adoption by the Linux kernel in being able to pass bootloader or system firmware logs to the operating system kernel for in turn exposing them to user-space.
An Akamai engineer inquired over a year ago to the GRUB development community about being able to debug remote hardware without a KVM. The desire arose for being able to read GRUB bootloader messages from within the running Linux environment. After discussing among GRUB developers and an early specification they began debating earlier this year, Oracle's Daniel Kiper has taken to the Linux kernel mailing list to gauge upstream kernel interest in such a specification and ultimately supporting it.
The goal would be to allow the OS kernel to either process such firmware/boot logs and where relevant to expose them to user-space. The specification is designed to be platform agnostic and self-contained.
The "bf_log" would contain arbitrary messages to pass to the booted kernel. The specification is around defining that format and related details. But still to be settled upon is for how to present such logs to the operating system. The likely path for passing such information would be UEFI config tables and other similar avenues available on ACPI and DeviceTree platforms.
If the ability to access bootloader / early system firmware logs from a booted Linux kernel are of possible interest to you, the specification proposal is worth looking into. Right now the developers are working to settle the spec before going through and working out the actual patches for the likes of GRUB and the Linux kernel.