[OpenBIOS] [PATCH] ppc: use rfid when running under a CPU from the 970 family.

[Mark Cave-Ayland]

On 21/06/16 07:09, Cédric Le Goater wrote:

> On 06/21/2016 04:18 AM, Benjamin Herrenschmidt wrote:
>> On Mon, 2016-06-20 at 17:42 +0200, Cédric Le Goater wrote:
>>> flushing the cache does not seem necessary. I suppose because we did not go 
>>> through this range of instructions yet, I am not sure how qemu handle 
>>> the cache instructions. Need to check.
>>>
>>> Thanks, I will bake a patch for it. 
>>
>> The cache might prefetch, you need to do the dcbf/sync/icbi/isync dance
>> (it's not needed on modern processors but is on older ones so better
>> safe than sorry in openbios).
>>
>> You didn't see a problem also because qemu doesn't care ;-)
> 
> I see. I will add a flush_icache_range(). 

Yes indeed. I think the other architectures are still playing catch-up
here, however PPC already has a flush_icache_range() function in
arch/ppc/qemu/start.S ready to go.


ATB,

Mark.