From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tim Deegan <tim@xen.org>
Subject: Re: [PATCH 13/45] xen: arm64: dcache flush
Date: Thu, 7 Feb 2013 16:14:32 +0000
Message-ID: <20130207161432.GN77133@ocelot.phlegethon.org>
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	<1358956611-8432-13-git-send-email-ian.campbell@citrix.com>
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To: Ian Campbell <ian.campbell@citrix.com>
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At 15:56 +0000 on 23 Jan (1358956579), Ian Campbell wrote:
> This drops the
>     "m" (*_p)
> asm contraint. I can't figure out what this was for.
> 

It's to stop the compiler hoisting writes to the wrong side of the
flush.  It's the lighter-weight equivalent to the "memory" clobber in
the range version.  By moving from inline "dsb;" to dsb() you've
reintroduced the full memory clobber here anyway. :(