From mboxrd@z Thu Jan  1 00:00:00 1970
From: benh@kernel.crashing.org (Benjamin Herrenschmidt)
Date: Sun, 06 May 2018 11:56:44 +1000
Subject: [RFC PATCH] locking/atomics/powerpc: Introduce optimized
 cmpxchg_release() family of APIs for PowerPC
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On Sat, 2018-05-05 at 12:00 +0200, Ingo Molnar wrote:
> This clearly suggests that PPC_RELEASE_BARRIER is in active use and 'lwsync' is 
> the 'release barrier' instruction, if I interpreted that right.

The closest to one we got.

The semantics are that it orders all load/store pairs to cachable
storage except store+load.

Cheers,
Ben.