Re: [PATCH] arm64: signal: Update sigcontext reservations table

[Dave Martin <Dave.Martin@arm.com>]

On Wed, Sep 04, 2024 at 12:49:03PM +0100, Mark Brown wrote:
> On Wed, Sep 04, 2024 at 12:24:24PM +0100, Dave Martin wrote:
> > On Tue, Sep 03, 2024 at 07:26:04PM +0100, Mark Brown wrote:
> 
> > > It be good to add a selftest that flags this, that way people might
> > > notice when adding things and if we miss something it'll probably turn
> > > up in one of the CIs at some point (possibly after it's too late but at
> > > least we'd know).  That'd give us some level of integration test with
> > > whatever libcs and other default software are actually doing, as opposed
> > > to what we think they'll do.
> 
> > I suppose we could write a test that sets VL=64, SVL=32 and dirties the
> > SVE and SME regs before triggering a signal, then checks that
> > extra_context is not there.  This will only work if SVE and SME are
> > present and big enough.  If we can run this as a routine CI test on a
> > model, it might be useful though.
> 
> I'd also run this test with the default settings for the system, it
> might help people notice if they've configured their system in some
> way that causes issues unexpectedly.

Probably; though if they've increased the sve_default_vector_length or
sme_default_vector_length, they're on their own!

Having a test that flags this up probably no bad thing though.

Cheers
---Dave