ARM: add a kuser_cmpxchg64 user space helper
authorNicolas Pitre <nicolas.pitre@linaro.org>
Mon, 20 Jun 2011 03:36:03 +0000 (23:36 -0400)
committerNicolas Pitre <nico@fluxnic.net>
Tue, 28 Jun 2011 19:47:47 +0000 (15:47 -0400)
commit40fb79c8a88625504857d44de1bc89dc0341e618
tree1f0e417a1f1c80fcaa79729f1a4b29e96f01fed2
parent37b8304642c7f91df54888955c373ae89b577fcc
ARM: add a kuser_cmpxchg64 user space helper

Some user space applications are designed around the ability to perform
atomic operations on 64 bit values.  Since this is natively possible
only with ARMv6k and above, let's provide a new kuser helper to perform
the operation with kernel supervision on pre ARMv6k hardware.

Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Tested-by: Dave Martin <dave.martin@linaro.org>
Documentation/arm/kernel_user_helpers.txt
arch/arm/kernel/entry-armv.S