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Date: Thu, 26 May 2005 09:54:14 -0700
From: Eugene Surovegin <ebs@ebshome.net>
To: Matt Porter <mporter@kernel.crashing.org>
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Cc: linuxppc-dev list <linuxppc-dev@ozlabs.org>, linuxppc-embedded@ozlabs.org
Subject: Re: RFC: Deprecating io_block_mapping
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On Thu, May 26, 2005 at 09:31:19AM -0700, Matt Porter wrote:
> Why don't we try a different approach to the problem? The problem is
> that io_block_mapping() is causing a ton of problems with people
> abusing it. Just check the archives for all the ways people break
> their ports by passing it arbitrary values.  The other issue is
> that although it's dangerous, the call still serves a purposes on
> those processors with BATs and CAMs. So, let's kill io_block_mapping().
> i.e. the version that allows virt->phys translations to be set up
> without use of BATs and CAMs. Let's add a new mmu_block_mapping()
> call that will ONLY map using a BAT or CAM and is only available
> on platforms with those facilities. If a free BAT or CAM is not available
> or alignment/size is invalid, the call fails. I would hope that would
> make everybody happy.
> 
> We still end up with a call that will help people shoot themselves
> in the foot, but at least we limit it to a specific task.

I second that.

-- 
Eugene