Re: [PATCH v2 08/25] arm64: Always keep DAIF.[IF] in sync

Mark Rutland
2021-02-18T15:28:40Z

On Thu, Feb 18, 2021 at 11:42:01PM +0900, Hector Martin wrote:
> On 18/02/2021 23.22, Mark Rutland wrote:
> > I think that for consistency we always want to keep IRQ and FIQ in-sync,
> > even when using GIC priorities. So when handling a pseudo-NMI we should
> > unmask DAIF.DA and leave DAIF.IF masked.
>
> In that case there's one more, in daifflags.h:local_daif_restore():
>
> /*
> * If interrupts are disabled but we can take
> * asynchronous errors, we can take NMIs
> */
> flags &= PSR_I_BIT;
> pmr = GIC_PRIO_IRQOFF;

Good spot, yes!

I did a quick scan with `git grep 'PSR_[IF]_BIT' -- arch/arm64`, and
AFAICT that's the last one.

> > > And a minor related one: should init_gic_priority_masking() WARN if FIQ is
> > > masked too? This probably goes with the above.
> >
> > I think it should, yes.
>
> Done for v3 then. Thanks!

Cool!

Mark.