[RFC v2 6/7] powerpc: atomic: Make atomic{,64}_xchg and xchg a full barrier

[Peter Zijlstra]

On Wed, Sep 16, 2015 at 11:49:34PM +0800, Boqun Feng wrote:
> According to memory-barriers.txt, xchg and its atomic{,64}_ versions
> need to imply a full barrier, however they are now just RELEASE+ACQUIRE,
> which is not a full barrier.
> 
> So remove the definition of xchg(), and let __atomic_op_fence() build
> the full-barrier versions of these operations.

Do you want to do a patch for -stable fixing the current implementation?