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Subject: Re: [PATCH V2 26/68] powerpc/mm/radix: Add radix pte defines
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Balbir Singh <bsingharora@gmail.com>, "Aneesh Kumar K.V"
 <aneesh.kumar@linux.vnet.ibm.com>, paulus@samba.org, mpe@ellerman.id.au
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Date: Sat, 23 Apr 2016 18:30:19 +1000
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On Thu, 2016-04-21 at 14:12 +1000, Balbir Singh wrote:
> > +     } while (cpu_to_be64(old_pte) != __cmpxchg_u64((unsigned long *)ptep,
> > +                                                    cpu_to_be64(old_pte),
> > +                                                    cpu_to_be64(new_pte)));
> > +     /* We already do a sync in cmpxchg, is ptesync needed ?*/
> > +     asm volatile("ptesync" : : : "memory");
> 
> Yes, I think ptesync is required after PTE changes

Is it really on radix ? I'm not 100% sure... it's usually needed to
synchronize the writebacks of R and C...

Cheers,
Ben.