Re: [PATCH 3/6] kselftest/arm64: Corrupt P15 in the irritator when testing SSVE

[Mark Brown]

On Wed, Nov 06, 2024 at 11:27:24AM +0000, Mark Rutland wrote:

> > +#ifndef SSVE
> >  	// And FFR
> >  	wrffr	p15.b
> >  #endif

> Both RDFFR and WRFFR are illegal in streaming mode unless FEAT_FA64 is
> implemented and enabled, so we cannot use DRFFR in the SSVE case.

Indeed, I'm surprised that managed to pass my testing...

> Is there a different instruction we can use?

We could just trash p0 with something like a load or add.

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