Interesting csd deadlock on ARC

[Noam Camus]

>From: Peter Zijlstra [mailto:peterz at infradead.org] 
>Sent: Tuesday, February 23, 2016 12:40 PM

>The only requirement for irq_work is that it runs after the NMI completes and runs from regular IRQ context. >There are no strict interrupt priority requirements, only that it happens.

We here already use self IPI and irq_work on ARC (with no NMI concerns).
Please see patch at:
https://github.com/EZchip/linux/commit/e42556738e610295f917c79dae166373cd11de88

Noam