getting KEVS for booting DFly

getting KEVS for booting DFly

[Artsimovich, Wladislav]

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Dear GRUB team,

I'm interested in getting DragonFlyBSD to boot without a BIOS environment (e.g. using coreboot / libreboot with the coreboot-grub payload to load the kernel directly) and require some help getting information to relay to the DFly devs to make this possible.

Booting the kernel directly is possible for FreeBSD via the kfreebsd command. DragonFlyBSD, a fork of FreeBSD doesn't work with this command and crashes / gets stuck without producing any error and freezes the screen. Also the DFly boot loader doesn't run without a BIOS environment either.
It was explained to me in the FreeBSD IRC channel, that kfreebsd passes a bunch of "KEVS" (Kernel environment variables) to the kernel to make it boot. The theory that the channel proposed is that these KEVS are incompatible with DFly's Kernel. The DFly team however has no time to investigate this.
I would like to compile a list of KEVS, that kfreebsd passes to the FreeBSD kernel to make it boot and give that list to the DFly devs. Then they would compare the list with what the DFLY kernel expects and figure out what is incompatible and whether it is possible to make it compatible within a reasonable time frame.
I have no experience with such low level stuff however.

Where can I find how many and which KEVS are passed to the kernel by kfreebsd?
Which source files would I have to go through to compile such a list?
What am I looking for when parsing said source files?


Best regards,

Vlad

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Re: getting KEVS for booting DFly

[Daniel Kiper]

I am not familiar with BSD but...

On Thu, Mar 07, 2019 at 04:42:47PM +0000, Artsimovich, Wladislav wrote:
> Dear GRUB team,
>
> I'm interested in getting DragonFlyBSD to boot without a BIOS environment (e.g. using coreboot / libreboot with the coreboot-grub payload to load the kernel directly) and require some help getting information to relay to the DFly devs to make this possible.
>
> Booting the kernel directly is possible for FreeBSD via the kfreebsd command. DragonFlyBSD, a fork of FreeBSD doesn't work with this command and crashes / gets stuck without producing any error and freezes the screen. Also the DFly boot loader doesn't run without a BIOS environment either.
> It was explained to me in the FreeBSD IRC channel, that kfreebsd passes a bunch of "KEVS" (Kernel environment variables) to the kernel to make it boot. The theory that the channel proposed is that these KEVS are incompatible with DFly's Kernel. The DFly team however has no time to investigate this.
> I would like to compile a list of KEVS, that kfreebsd passes to the FreeBSD kernel to make it boot and give that list to the DFly devs. Then they would compare the list with what the DFLY kernel expects and figure out what is incompatible and whether it is possible to make it compatible within a reasonable time frame.
> I have no experience with such low level stuff however.
>
> Where can I find how many and which KEVS are passed to the kernel by kfreebsd?
> Which source files would I have to go through to compile such a list?

grub-core/loader/i386/bsd.c?

> What am I looking for when parsing said source files?

In general I think that "grep -Iir kfreebsd" in GRUB source directory is
your friend.

Daniel