commit bf3ec9ad52a5ccaccdae843a94f964f3a7624ecd
author Serban Constantinescu <serban.constantinescu@arm.com> Thu Dec 19 11:46:17 2013 +0000
committer David Butcher <david.butcher@arm.com> Thu Dec 19 18:32:53 2013 +0000
tree 61952ac46346f7149c5b2694b5341978262bbe74
parent 81ddd14381b09f171c006ebcbba15b3c1baf2a9f

AArch64: Use LDXR/STXR instead of LDAXR/STLXR for bionic_atomic_cmpxchg()

The bionic_atomic_cmpxchg() API states that the cmpxchg() will be done without
explicit memory barriers. LDAXR/STLXR semantics involve half barriers for
load/store.

This patch optimises cmpxchg() by using LDXR/STXR and avoiding unnecessary half
bariers. It also fixes the clobber list for all the bionic_atomic_*() functions.

Change-Id: Iae9468965785cfeeec791d52f1e8cbc524adb682
Signed-off-by: Serban Constantinescu <serban.constantinescu@arm.com>