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Subject: Re: Inline Assembly queries
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: David Howells <dhowells@redhat.com>
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Date: Tue, 30 Jun 2009 20:43:03 +1000
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On Mon, 2009-06-29 at 16:57 +0100, David Howells wrote:
> kernel mailz <kernelmailz@googlemail.com> wrote:
> 
> > asm("sync");
> 
> Isn't gcc free to discard this as it has no dependencies, no indicated side
> effects, and isn't required to be kept?  I think this should probably be:
> 
> 	asm volatile("sync");

It should also have a "memory" clobber or it's pointless since gcc would
otherwise be free to move load and stores accross that barrier.

Cheers,
Ben.