[BULK] RFC: Generic shadow mechanism useable from a payload

[Eric W. Biederman]

Richard Smith <smithbone at gmail.com> writes:

> > Yes you can do that with ELF.
> > 
> > The big gotcha is going to be that there are pirq tables current
> > stored at 0xf0000 that you are not going to want to stomp.
> 
> Actually thats not that much of an issue. It currently stomps it already
> 
> ADLO has that table broken out into a single binary file.  All I do is
> copy the table binary table generated with linubios into the adlo
> build file and it gets stuck in the adlo image.   Loader.s copies it
> to a specific location.
> So really if you loaded loader and ADLO code after the linuxbios PIRQ
> table location and then tweaked loader to not make a PIRQ it should be
> fine.
> 
> Not haveing to do the PIRQ table copy would be nice but its pretty
> trival.  A script to do it automatically would be easy.

The fact that ADLO has to manually customized per board is what
keeps it from being a lot more generally usable.
  
> > The fun question.  Can I make the bochs bios useable on a system
> > after the linux kernel has run.  Load it with kexec and then boot windows?
> > 
> > If LinuxBIOS is the native bios this should be no extra challenge.  If the
> > native BIOS is something else life gets a little more interesting.
> 
> That _is_ a fun quesition..  I don't think you would have too many
> problems though.  The ADLO bios is used to running on systems that
> already have everything setup.  It does minimal hardware setup.  If
> you put everything in the right spot and modified the loader so that
> it didn't copy anything  I think it will work.
> 
> kexec loads an elf right?  So this would be pretty easy to test.

Yes /sbin/kkexec loads an elf among other things.

Eric