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From: will.deacon@arm.com (Will Deacon)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH] ARM: io: avoid writeback addressing modes for __raw_ accessors
Date: Mon, 20 Aug 2012 19:10:08 +0100	[thread overview]
Message-ID: <20120820181007.GX25864@mudshark.cambridge.arm.com> (raw)
In-Reply-To: <alpine.LFD.2.02.1208201356130.1754@xanadu.home>

On Mon, Aug 20, 2012 at 07:04:01PM +0100, Nicolas Pitre wrote:
> On Mon, 20 Aug 2012, Will Deacon wrote:
> > 
> > Hmm, ok. I too would hope that the volatile keyword would sort that out but,
> > since the '+' doesn't seem to change the generated code, I can add that. It
> > does, however, mean we have to cast away the `const' in the read accessors
> > which makes the code even uglier.
> 
> Nah... the const is wrong.  The way you wrote it means that addr may 
> change but the pointed data is constant.  This is obviously wrong since 
> we expect the pointed location to change even from a read.

That's the prototype for the read accessors though -- a bunch of other
architectures define them that way (including asm-generic), so I wonder what
the reasoning behind that was?

Will

  reply	other threads:[~2012-08-20 18:10 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-08-14 14:59 [PATCH] ARM: io: avoid writeback addressing modes for __raw_ accessors Will Deacon
2012-08-17  3:43 ` Nicolas Pitre
2012-08-20 12:41   ` Will Deacon
2012-08-20 13:29     ` Nicolas Pitre
2012-08-20 14:49       ` Will Deacon
2012-08-20 16:09         ` Nicolas Pitre
2012-08-20 16:54           ` Will Deacon
2012-08-20 18:04             ` Nicolas Pitre
2012-08-20 18:10               ` Will Deacon [this message]
2012-08-20 18:45                 ` Nicolas Pitre
2012-08-21  9:02                   ` Will Deacon
2012-08-21 10:11                     ` Arnd Bergmann
2012-08-21 12:33                     ` Nicolas Pitre

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