On Thu, 2015-08-27 at 13:56 -0400, Mathieu Desnoyers wrote:

Allow it to be used from SPU, since it should not have unwanted
side-effects.

[ Untested on this architecture. To try it out: fetch linux-next/akpm,
  apply this patch, build/run a membarrier-enabled kernel, and do make
  kselftest. ]

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: linux-api@vger.kernel.org
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Paul Mackerras <redacted>
CC: Michael Ellerman <mpe@ellerman.id.au>
CC: linuxppc-dev@lists.ozlabs.org

Thanks.

I get:

$ ./membarrier_test
membarrier MEMBARRIER_CMD_QUERY syscall available.
membarrier: MEMBARRIER_CMD_SHARED success.
membarrier: tests done!

Which looks good.

Assuming the membarrier support hits 4.3, I'll take this via my tree for 4.3
also.

cheers