[ipxe-devel] SRP booting linux, SRP volume with ISO stops seeing itself

[Michael Brown]

On 18/07/16 02:39, james harvey wrote:
> I hope I'm wrong here, but I think there needs to be an additional
> kernel module to allow SRP booting.  Has no one done this yet, booted
> linux by SRP, or am I off somewhere?
>
> I do have a program that can search a given 640k area, and find and
> parse a sBFT.  (Probably needs a tweak or two once I'm running it on
> what iPXE leaves behind, rather than the test structures I'm randomly
> making and randomly placing.)
>
> Now that I'm at the point of wanting to try it during boot, I realized
> what I should have earlier - I don't think there's any way for my
> program to access the sBFT.

You should be able to mmap() /dev/mem, which will give you access to the 
low 1MB of physical address space from a userspace program.  The sBFT 
will be preserved within this region.

Michael