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Subject: Re: [PATCH -V10 10/15] powerpc: Prevent gcc to re-read the pagetables
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: David Laight <David.Laight@ACULAB.COM>
Date: Thu, 06 Jun 2013 08:39:38 +1000
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 "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
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On Wed, 2013-06-05 at 16:41 +0100, David Laight wrote:
> >  	ptep = pte_offset_kernel(&pmd, addr);
> >  	do {
> > -		pte_t pte = *ptep;
> > +		pte_t pte = ACCESS_ONCE(*ptep);
> 
> Why not just define ptep as a 'pointer to volatile'?

ACCESS_ONCE is the proper way to do it in Linux. pointer to volatile
can have ... interesting semantics.

Cheers,
Ben.