Getting kernels to boot other kernels?

Eric W. Biederman ebiederman at lnxi.com
Fri Nov 1 09:57:00 CET 2002


Ronald G Minnich <rminnich at lanl.gov> writes:

> On Thu, 31 Oct 2002, Kevin Hester wrote:
> 
> > I recall reading a white paper about Linuxbios and patches so that the kernel
> > can boot other kernels?  Does anyone know where this code is?  I've poked
> > around with no luck.
> 
> just go with kexec, it's the standard now for 2.5. There are other
> packages but my inclination is to go with whatever comes with the base
> kernel.

Ron that logic unfortunately does not work.  So far Linus has just
ignored kexec.   kexec is the only one available for 2.5.x though.

> > For our application, I'd like to place a minimal kernel into the FLASH with
> > the BIOS.  That kernel would either use IP or IDE to read in the 'real'
> > kernel.
> 
> that's how we do it here. Works quite nicely.
> 
> > I considered chaining into Etherboot, but I need to boot from IDE drives in
> > addition to Ethernet.  The Etherboot CAN_BOOT_DISK flag seems to require IDE
> > read funtionality in the BIOS (a no-no with linuxbios?).
> 
> No, there is an ide driver in etherboot. But you get no filesystems.
> 
> There is a point of disagreement in this community: is linux too heavy to
> be a boot loader, but is its complexity needed; is etherboot a nice and
> light and fast bootloader, but is it too simplistic. That is the
> disagreement described in its broadest form.
> 
> For now, here at lanl, we come down on the side of using Linux wherever
> possible and we have been happy with that decision. Just yesterday I had a
> problem with etherboot that was solved by using Linux as the bootloader
> instead. Overall I prefer using Linux as my bootloader, but I am also
> extremely impressed with etherboot's growing capabilities.

If I could seriously get the attention of the kernel developers.  And
stabalize the kernel so it properly shutdown the hardware I would be
more persuaded.  At least until I can get kexec into the kernel or we
start a our own kernel tree for network booting and develop from
there I am not especially interested in using the Linux kernel because
it does not work correctly.

Eric




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