[coreboot] resuming a kernel directly from coreboot?

[ron minnich]

On Mon, Oct 20, 2008 at 8:42 AM, Matt Price <matt.price at utoronto.ca> wrote:

> - the suspened image is saved to a swap partition, whose location needs
> to be specified within the initramfs which will be part of the payload.
> i don't know if that's a problem or not; presumably one would set it up
> outside of any LVM, RAID, or more complex arrangement.

yes, if you're going to have an LVM or RAID backing it, you're
probably going to want linux to boot it.

But if it is simple, you could extend FILO to know what do to.

> - as i understand it (and i'm not sure about this) kernels since 2.6.26
> can use a hibernation image written by another kernel.  So when there is
> a valid suspended image in the right place, kernel A simply activates
> the normal resume sequence, and we automatically end up with kernel B at
> the end of the resume process.

Then just put linux in flash. I expect this system uses kexec.

> - one would need some other process for booting kernel B in cases where
> there's no good hibernation image -- like on the system's first boot! --
> i guess one could use kexec in an initramfs script.  I haven't put this
> system together yet so I don't know whether there might be driver issues
> using kexec.

I have used kexec a lot. I don't see what driver issues could come up,
as long as Kernel A has the right drivers built in.

>
> i guess one could start with a proof-of-concept minimal kernel in qemu &
> see if things work?  i'm not sure how well the in-kernel suspend works
> with qemu, though -- i've always used the "save state" option there...
>

qemu should be a fine testbed for this idea.

I hope you try it out -- it sounds neat.

ron