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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Ard Biesheuvel <ardb+git@google.com>
Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Ard Biesheuvel <ardb@kernel.org>, Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2 0/7] arm64: Make EFI calls preemptible
Message-ID: <20250915085244.JLUfpdSP@linutronix.de>
References: <20250905133035.275517-9-ardb+git@google.com>
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In-Reply-To: <20250905133035.275517-9-ardb+git@google.com>

On 2025-09-05 15:30:36 [+0200], Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@kernel.org>
>=20
=E2=80=A6
> Note that this is only a partial solution in terms of RT guarantees,
> given that the runtime services execute at the same privilege level as
> the kernel, and can therefore disable interrupts (and therefore
> preemption) directly. But it should prevent scheduling latency spikes
> for EFI calls that simply take a long time to run to completion.

That sounds nice. There is no feature flag that could tell if a specific
EFI-call (or any) will disable interrupts, right? But if the source code
is available, you could check.

Sebastian