Subject: Re: [PATCH V2 26/68] powerpc/mm/radix: Add radix pte defines

From: Balbir Singh <[email-masked]>
Date: Tue, 26 Apr 2016 11:40:25 +1000

On 23/04/16 18:30, Benjamin Herrenschmidt wrote:
> 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...
> 

pte_update could be called to update R/reset R bit. I'll read the manual to see if I can find anything more specific

Balbir Singh.