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

Benjamin Herrenschmidt
2008-05-20T22:02:38Z

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...

Ben.