From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Kumar Gala <galak@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org
Subject: Re: [PATCH] powerpc/book3e: Fix extlb size
Date: Wed, 06 Apr 2011 09:39:09 +1000 [thread overview]
Message-ID: <1302046749.2549.186.camel@pasglop> (raw)
In-Reply-To: <F4D669C2-BAD4-4B79-BE24-FB5AD2961160@kernel.crashing.org>
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.
next prev parent reply other threads:[~2011-04-05 23:39 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 [this message]
2011-04-06 1:45 ` Kumar Gala
-- 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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