Subject: Re: Kernel CRC
To: Chris G. Demetriou <>
From: Steve Woodford <>
List: tech-kern
Date: 09/19/1999 19:58:20
On 19 Sep 1999, Chris G. Demetriou wrote:

> I think something like this is inherently machine-dependent.  I mean,
> the hardest part of it is probably figuring out _where_ to put the
> checksum (and how to keep that out of the way of the checksum code
> 8-).  Further, for some machines it doesn't even make any sense,
> because the kernel is loaded directly by the firmware, which doesn't
> do any such check...

From that it would seem that the best place for the check is early on in
the kernel's startup code, possibly a simple CRC in locore.s (with the
appropriate frobbing if the MMU is disabled). If the self-check code
itself is corrupted, your going nowhere anyway.

In this case, it would be completely MD such that ports which "trust"
their bootloaders don't need to do anything. ;-)

Cheers, Steve