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Subject: Re: [PATCH] powerpc/mm: Fix 40x and 8xx vs. _PAGE_SPECIAL
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Rex Feany <RFeany@mrv.com>
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Date: Thu, 24 Sep 2009 12:53:35 +1000
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Cc: Scott Wood <scottwood@freescale.com>,
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	Bernhard" <Bernhard.Weirich@riedel.net>
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On Wed, 2009-09-23 at 19:38 -0700, Rex Feany wrote:
> Thus spake Benjamin Herrenschmidt (benh@kernel.crashing.org):
> 
> > Hrm. This is really strange...
> 
> Is this a problem? in pte-8xx.h you added:
> 
> +#define _PAGE_SPECIAL  0x0008  /* SW entry, forced to 0 by the TLB miss */
> 
> but there is already this:
> 
> #define _PAGE_EXEC      0x0008  /* software: i-cache coherency required */

Ohhh... you aren't using upstream ! That explains :-)

I removed _PAGE_EXEC from 8xx (since it doesn't use it for anything)
recently.

I think the best option is to go for Bernhard's patch for "stable" and
my patch for upstream, so that "stable" gets the bug fix without the
feature of _PAGE_SPECIAL and upstream gets it both.

Cheers,
Ben.