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Subject: Re: [PATCH] powerpc: Avoid panic during boot due to divide by zero
 in init_cache_info()
From: Benjamin Herrenschmidt <benh@au1.ibm.com>
Reply-To: benh@au1.ibm.com
To: Segher Boessenkool <segher@kernel.crashing.org>
Cc: Gabriel Paubert <paubert@iram.es>, paulus@samba.org,
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Date: Mon, 06 Mar 2017 11:20:26 +1100
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On Sun, 2017-03-05 at 18:10 -0600, Segher Boessenkool wrote:
> You cannot really have something at address 0, the way NULL pointers
> are represented in GCC.  0 in firmware, so *fun*, especially before
> the
> CFAR was invented.  "Something jumped to 0, CTR is 0 so it's probably
> a BCTR, but which one of the 6000?"
> 
> What do you have at 0?  Not anything you need often I hope?

I think it was some kind of boot flag. I've had cases also of
copying the 0..0x100 region over with the kexec gunk etc...

Ben.