Re: [PATCH 2/2] s390x: add test for SIGP STORE_ADTL_STATUS order

[Nico Boehr <nrb@linux.ibm.com>]

On Tue, 2022-03-29 at 13:39 +0200, Janosch Frank wrote:
> > I think that won't work because that function might clean its float
> > registers in the epilogue and hence destroy the contents. Except if
> > you
> > have an idea on how to avoid that?

I missed that this is a theoretical problem because the function will
be inlined anyway.

> About that:
> 
> Well, who guarantees you that the compiler won't change a fpr (and 
> thereby the overlapped vrs) between the vlms here and your infinite
> loop 
> at the end of the function? :-) gcc uses fprs and acrs in the most 
> interesting places and I've just been hit by that again a few hours
> ago.
> 
> I.e. to be safe we'll need to implement the next few lines in
> assembly 
> as well, no?

I guess so. I will go ahead and reimplement everything in assembly?