From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Scott Wood <scottwood@freescale.com>
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc/book3e-64: use a separate TLB handler when linear map is bolted
Date: Thu, 23 Jun 2011 08:05:33 +1000 [thread overview]
Message-ID: <1308780333.32158.171.camel@pasglop> (raw)
In-Reply-To: <20110622162457.1016390e@schlenkerla.am.freescale.net>
On Wed, 2011-06-22 at 16:24 -0500, Scott Wood wrote:
>
> This saved another 1% or so. I don't think TLB_SCRATCH needs to be saved
> by crit/debug/mcheck -- they shouldn't be taking TLB misses, at least
> in the bolted case.
The code they call will (think accessing the UART)
> Even non-bolted, it doesn't look like there are enough
> extlb levels to deal with a linear TLB miss inside a crit/debug/mcheck
> inside a linear TLB miss inside a virtual page table miss inside a normal
> TLB miss.
My plan for crit/debug/mcheck (which I haven't implemented yet) was to
save the whole TLB save area onto the kernel stack and restore it.
> Currently, we could just as well take that crit/debug/mcheck after
> storing to TLB_SCRATCH but before saving it to extlb, and have the same
> problem.
Right. My point was more that TLB_SCRATCH itself shall be saved
somewhere by the crit/debug/mcheck handler along with the copy of the
TLB save area.
Cheers,
Ben.
prev parent reply other threads:[~2011-06-22 22:05 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-06-03 22:12 [PATCH] powerpc/book3e-64: use a separate TLB handler when linear map is bolted Scott Wood
2011-06-17 2:00 ` Benjamin Herrenschmidt
2011-06-17 16:32 ` Scott Wood
2011-06-17 22:44 ` Benjamin Herrenschmidt
2011-06-22 21:24 ` Scott Wood
2011-06-22 22:05 ` Benjamin Herrenschmidt [this message]
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