linux-kernel - Re: [PATCH] arm64/gcs: Don't try to access GCS registers if arm64.nogcs is enabled

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Message-Id: <175164295299.1186581.5911372267444093930.b4-ty@kernel.org>
Date: Fri,  4 Jul 2025 18:44:11 +0100
From: Will Deacon <will@...nel.org>
To: Catalin Marinas <catalin.marinas@....com>,
	Mark Brown <broonie@...nel.org>
Cc: kernel-team@...roid.com,
	Will Deacon <will@...nel.org>,
	linux-arm-kernel@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] arm64/gcs: Don't try to access GCS registers if arm64.nogcs is enabled

On Thu, 19 Jun 2025 22:15:41 +0100, Mark Brown wrote:
> During EL2 setup if GCS is advertised in the ID registers we will reset the
> GCS control registers GCSCR_EL1 and GCSCRE0_EL1 to known values in order to
> ensure it is disabled. This is done without taking into account overrides
> supplied on the command line, meaning that if the user has configured
> arm64.nogcs we will still access these GCS specific registers. If this was
> done because EL3 does not enable GCS this results in traps to EL3 and a
> failed boot which is not what users would expect from having set that
> parameter.
> 
> [...]

Applied to arm64 (for-next/fixes), thanks!

[1/1] arm64/gcs: Don't try to access GCS registers if arm64.nogcs is enabled
      https://git.kernel.org/arm64/c/0d1c86b84096

Cheers,
-- 
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev