[PATCH v1 12/38] arm64/sme: Provide ABI documentation for SME

[Szabolcs Nagy]

The 10/13/2021 19:37, Mark Brown wrote:
> On Tue, Oct 12, 2021 at 09:23:21AM +0100, Szabolcs Nagy wrote:
> > The 10/11/2021 21:10, Mark Brown wrote:
> 
> > > OK, that makes sense.  I've changed the code and the kselftest so that
> > > TPIDR2 is preserved on thread creation.
> 
> > does thread creation have to work the same way as fork?
> 
> > (in a pthread_create child we want tpidr2 to be 0,
> > since it represents thread specific data. in a fork
> > child we want to preserve tpidr2 to mirror the
> > state of the parent as much as possible)
> 
> ...
> 
> > i'm not sure when to do tpidr2=0 exactly, but something
> > like CLONE_SETTLS is set or child runs on a new stack
> > would work for me. if that's too ugly then preserving
> > tpidr2 in the child is fine.
> 
> Resetting it on CLONE_SETTLS is straightforward to implement so if that
> works for you it sounds good to me, I've got it implemented locally
> already with a test case.

thanks, i think that makes sense and works for thread implementations.