Re: [PATCH] [POWERPC] Improve (in|out)_beXX() asm code

From: Benjamin Herrenschmidt
Date: Tue May 20 2008 - 18:02:39 EST

On Tue, 2008-05-20 at 16:38 -0500, Scott Wood wrote:
> It looks like we rely on -fno-strict-aliasing to prevent reordering
> ordinary memory accesses (such as to DMA descriptors) past the I/O
> access. It won't prevent reordering of memory reads around an I/O
> read,
> though, which could be a problem if the I/O read result determines
> the
> validity of the DMA buffer. IMHO, a memory clobber would be better.

We probably want a full "memory" clobber then...


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