Subject: Re: Kernel 4.7: PAGE_GUARDED and _PAGE_NO_CACHE

From: "Aneesh Kumar K.V" <[email-masked]>
Date: Sat, 04 Jun 2016 20:12:15 +0530

Christian Zigotzky <[email-masked]> writes:

> Aneesh,
>
> Could you please send me only your patch for the Power ISA 3.0 (Power9) 
> Radix Tree MMU? You have done the most modifications for the kernel 4.7. 
> If the kernel boots with your modifications then I have to look to the 
> other few modifications.
>
> Thanks in advance,
>

Are you looking for changes too kernel that will add ISA 3.0 MMU model
without making changes to other part of kernel ?. I don't think we ever
had a kernel patch which did the ISA 3.0 work like that. In order to add
the new ISA support we did have to make changes to other part of the
kernel.

To debug your boot issue, I still haven't understood why the suggested
changes are not working. Because for a  non cache guarded page the
mapping didn't change at all. Hence I was asking for what the expected
WIMG values are for your board.

One other option is to bisect test the kernel and if you can isolate
which patch is breaking the boot, we can possibly understand it better.
ie, instead of reverting the entire merge, try a git bisect.

-aneesh