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Date:   Wed, 24 Mar 2021 17:00:00 +0000
From:   Will Deacon <will@kernel.org>
To:     Mark Rutland <mark.rutland@arm.com>
Cc:     linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        catalin.marinas@arm.com, james.morse@arm.com, marcan@marcan.st,
        maz@kernel.org, tglx@linutronix.de
Subject: Re: [PATCHv3 5/6] arm64: Always keep DAIF.[IF] in sync
Message-ID: <20210324165956.GD13030@willie-the-truck>
References: <20210315115629.57191-1-mark.rutland@arm.com>
 <20210315115629.57191-6-mark.rutland@arm.com>
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On Mon, Mar 15, 2021 at 11:56:28AM +0000, Mark Rutland wrote:
> From: Hector Martin <marcan@marcan.st>
> 
> Apple SoCs (A11 and newer) have some interrupt sources hardwired to the
> FIQ line. We implement support for this by simply treating IRQs and FIQs
> the same way in the interrupt vectors.
> 
> To support these systems, the FIQ mask bit needs to be kept in sync with
> the IRQ mask bit, so both kinds of exceptions are masked together. No
> other platforms should be delivering FIQ exceptions right now, and we
> already unmask FIQ in normal process context, so this should not have an
> effect on other systems - if spurious FIQs were arriving, they would
> already panic the kernel.
> 
> Signed-off-by: Hector Martin <marcan@marcan.st>
> Signed-off-by: Mark Rutland <mark.rutland@arm.com>
> Tested-by: Hector Martin <marcan@marcan.st>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: James Morse <james.morse@arm.com>
> Cc: Marc Zyngier <maz@kernel.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Will Deacon <will@kernel.org>
> ---
>  arch/arm64/include/asm/arch_gicv3.h |  2 +-
>  arch/arm64/include/asm/assembler.h  |  8 ++++----
>  arch/arm64/include/asm/daifflags.h  | 10 +++++-----
>  arch/arm64/include/asm/irqflags.h   | 16 +++++++---------
>  arch/arm64/kernel/entry.S           | 12 +++++++-----
>  arch/arm64/kernel/process.c         |  2 +-
>  arch/arm64/kernel/smp.c             |  1 +
>  7 files changed, 26 insertions(+), 25 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

Will