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

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Message-ID: <e66a9d0d-1127-c755-8bd7-7deedca1f3f3@marcan.st>
Date:   Thu, 18 Feb 2021 23:42:01 +0900
From:   Hector Martin <marcan@...can.st>
To:     Mark Rutland <mark.rutland@....com>
Cc:     Arnd Bergmann <arnd@...nel.org>, Rob Herring <robh@...nel.org>,
        Tony Lindgren <tony@...mide.com>,
        Marc Zyngier <maz@...nel.org>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-kernel@...r.kernel.org,
        Krzysztof Kozlowski <krzk@...nel.org>,
        devicetree@...r.kernel.org, Alexander Graf <graf@...zon.com>,
        Olof Johansson <olof@...om.net>,
        Mohamed Mediouni <mohamed.mediouni@...amail.com>,
        Stan Skowronek <stan@...ellium.com>,
        Will Deacon <will@...nel.org>,
        linux-arm-kernel@...ts.infradead.org,
        Mark Kettenis <mark.kettenis@...all.nl>
Subject: Re: [PATCH v2 08/25] arm64: Always keep DAIF.[IF] in sync

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;

>> 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!

-- 
Hector Martin (marcan@...can.st)
Public Key: https://mrcn.st/pub