From: Kumar Gala <galak@kernel.crashing.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] powerpc/book3e: Fix extlb size
Date: Tue, 5 Apr 2011 20:45:48 -0500 [thread overview]
Message-ID: <52FDCC6C-2F2F-47CC-8E6D-02A65FD21BCF@kernel.crashing.org> (raw)
In-Reply-To: <1302046749.2549.186.camel@pasglop>
On Apr 5, 2011, at 6:39 PM, Benjamin Herrenschmidt wrote:
> On Tue, 2011-04-05 at 07:41 -0500, Kumar Gala wrote:
>>> Rework it to make it a bit clearer, and also correct. We want 3 save
>>> areas, each EX_TLB_SIZE _bytes_.
>>
>> Where does the 3 come from? I have a guess, and think its possible we
>> (FSL) want 4?
>
> Wrong guess :-) It's not about exception levels. It's about how much
> the handler can re-enter (2 with E.PT, 3 with virtual linear)
>
> For MC's, CRITs etc... which we don't support on Book3E 64-bit at this
> stage, you'll have to probably backup the whole area... that or move
> the TLB frame pointer SPR to a separate set of 3 levels, but then you'd
> have to fix the code that makes assumption about level 0 being at a
> fixed offset in the PACA and instead use alignment tricks. We need that
> because that's how we "reset" the TLB frame when a second level finds
> a fault.
>
> Cheers,
> Ben.
Gotcha, can we add a comment here about what the '3' is about.
- k
next prev parent reply other threads:[~2011-04-06 1:46 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-04-05 6:28 [PATCH] powerpc/book3e: Fix extlb size Michael Ellerman
2011-04-05 12:41 ` Kumar Gala
2011-04-05 23:39 ` Benjamin Herrenschmidt
2011-04-06 1:45 ` Kumar Gala [this message]
-- strict thread matches above, loose matches on Subject: below --
2011-04-08 7:22 Michael Ellerman
2011-04-08 9:42 ` Kumar Gala
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