[PATCH 23/24] powerpc/mm: Cleanup check for stack expansion

[Michael Ellerman]

LEROY Christophe <christophe.leroy at c-s.fr> writes:

> Benjamin Herrenschmidt <benh at kernel.crashing.org> a écrit :
>
>> When hitting below a VM_GROWSDOWN vma (typically growing the stack),
>> we check whether it's a valid stack-growing instruction and we
>> check the distance to GPR1. This is largely open coded with lots
>> of comments, so move it out to a helper.
>
> Did you have a look at the following patch ? It's been waiting for  
> application for some weeks now.  
> https://patchwork.ozlabs.org/patch/771869

I actually merged it last merge window, but found I had no good way to
test it, so I took it out again until I can write a test case for it.

The way I realised it wasn't being tested was by removing all the
store_updates_sp logic entirely and having my system run happily for
several days :}

cheers