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.
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