Subject: Re: [PATCH v2] powerpc 8xx: Loading kernels over 8Mbytes without CONFIG_PIN_TLB

From: leroy christophe <[email-masked]>
Date: Tue, 17 Dec 2013 06:54:21 +0100

Le 16/12/2013 23:57, Scott Wood a écrit :
> On Wed, 2013-12-11 at 00:36 +0100, leroy christophe wrote:
>> Le 11/12/2013 00:18, Scott Wood a écrit :
>>> There wasn't previously an ifdef specifically around the setting of
>>> SPRN_MD_CTR.  That's new.  There was an ifdef around the entire block,
>>> which has gone away because you are now trying to map more than 8M
>>> regardless of CONFIG_PIN_TLB, but that has nothing to do with whether
>>> there should be an ifdef around SPRN_MD_CTR.
>>>
>>>
>> Euh, ok, but then we have to fix it in the whole function, not only in
>> this block. Do you think it is worth doing it ?
> Fix what in the whole function?  I was asking what harm there would be
> if you just remove all the CONFIG_PIN_TLB ifdefs except around the
> actual RSV4I setting -- do we really care what value goes in MD_CTR for
> the non-pinned case, as long as it's different for each entry?
>
>
MD_CTR is decremented after each entry added.
However, the function populates entry 28, then 29, then 30, then 31. At 
the end MD_CTR has then value 30, ready to overide entry 30 then 29 then 
28 then 27 .....

So I will remove all the CONFIG_PIN_TLB, but I'll also have to fix the 
value set in MD_CTR to start from 31, won't I ?

Do you have any comment/recommendation on my tentative v3 patch where I 
have tried to implement based on the use of r7 as you recommended ?

Christophe