[PATCH v9 14/14] powerpc: rewrite local_t using soft_irq

[Nicholas Piggin]

On Fri, 04 Aug 2017 11:40:43 +1000
Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> On Fri, 2017-08-04 at 03:50 +1000, Nicholas Piggin wrote:
> > Hey, so... why are any of these implemented in asm? We should
> > just do them all in C, right? I looked a bit harder at code gen
> > and a couple of them are still emitting larx/stcx.  
> 
> As long as we can guarantee that the C compiler won't play games
> moving stuff around. But yes, I tend to agree.


I believe so. I mean we already depend on the same pattern for any
other sequence of local_irq_disable(); c code; local_irq_enable();
so we'd have other problems if we couldn't.

I can easily believe there have been bugs with the fixed r13
handling in gcc in the past, but it looks like it does the right
thing now AFAIKS.

Thanks,
Nick