ARM: 7720/1: ARM v6/v7 cmpxchg64 shouldn't clear upper 32 bits of the old/new value
The implementation of cmpxchg64() for the ARM v6 and v7 architecture casts parameter 2 and 3 (the old and new 64bit values) to an unsigned long before calling the atomic_cmpxchg64() function. This clears the top 32 bits of the old and new values, resulting in the wrong values being compare-exchanged. Luckily, this only appears to be used for 64-bit sched_clock, which we don't (yet) have on ARM. This bug was introduced by commit 3e0f5a15 ("ARM: 7404/1: cmpxchg64: use atomic64 and local64 routines for cmpxchg64"). Cc: <stable@vger.kernel.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Jaccon Bastiaansen <jaccon.bastiaansen@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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