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Date: Tue, 30 Sep 2014 21:08:59 +0200
From: Peter Zijlstra <peterz@infradead.org>
To: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Rik van Riel <riel@redhat.com>, Arnd Bergmann <arnd@arndb.de>,
        Linus Torvalds <torvalds@linux-foundation.org>,
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        Ingo Molnar <mingo@kernel.org>, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] sched, time: fix build error with 64 bit cputime_t on 32
 bit systems
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References: <2547036.UshV4pXvhf@wuerfel>
 <20140930134011.232bc7bf@annuminas.surriel.com>
 <20140930190611.GA5702@lerouge>
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On Tue, Sep 30, 2014 at 09:06:13PM +0200, Frederic Weisbecker wrote:
> Maybe cmpxchg() should itself be a wrapper that does this build time choice
> between cmpxchg32() and cmpxchg64().
> 
> And if it looks too dangerous to convert all users, this could be cmpxchg_t().

It cannot, not all 32bit archs can do a 64bit cmpxchg.