Re: [coreboot] kernel payload

[Duncan Guthrie]

Hi,

In terms of the actual kernel, the same kernel can be used in theory, if 
you had a flash chip of a sufficient size. But there is no need to do 
this if you merely want to boot an OS. This is why I mentioned SeaBIOS - 
it can be used as a payload and it is what you will be used to. You can 
pretty much boot your OS as it is on-disk. It's a 16-bit BIOS, and it 
will likely "just work".

Initrd is optional in theory, that is, the kernel will boot - it's 
software after all. But it will get a kernel panic as it will not find 
anything to boot thereafter. You'll need to build your own initrd. You 
might find assistance in what the build system requires by selecting 
"help" for the option of initrd in the coreboot menuconfig. In the case 
of booting a kernel as payload directly from the flash chip, initrd will 
have to go there on the flash chip too.

-Duncan

On 05.05.2017 23:48, Healer64 via coreboot wrote:
> Hi Duncan,
>
> That really was one of the questions I was asking. Is there a
> difference between the linux kernel included in my os and the linux
> kernel coreboot uses as a payload?
>
> I wasn't aware including the initrd was optional. If it is not
> included in the rom image where does the kernel get it from? Disk?
>
> Sent with ProtonMail [1] Secure Email.

kernel payload

[ron minnich]

Duncan, I'm going to disagree with you  :-)

In the last years we've done all of these things:
- build initramfs into kernel, build kernel into flash, boot into that, and
that's all that's needed for a kiosk or other device
- use the initramfs to net boot the linux, first shown at LANL on HPC
systems in 2000.
- start the kernel and mount the root file system and run from that,
configure a network, boot from wireless or the disk (shown on the OLPC at
one point)
- put the kernel and initramfs in flash, boot that, dhcp configure the
network, wget a new kernel, gpgv that kernel, kexec that kernel, using a Go
userland to do all that (what we're doing at Google now as a demonstration)
- kernel in flash, nfs mount root, kexec kernel on that nfs mount point

Once you have a kernel in flash, the possibilities are fairly endless and
much more interesting that any bootloader I can think of.

ron