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Subject: Re: [PATCH v4 21/21] arm64: cpufeatures: Allow disabling of Pointer
 Auth from the command-line
To:     Catalin Marinas <catalin.marinas@arm.com>,
        Marc Zyngier <maz@kernel.org>
Cc:     linux-arm-kernel@lists.infradead.org, kvmarm@lists.cs.columbia.edu,
        linux-kernel@vger.kernel.org, Will Deacon <will@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        David Brazdil <dbrazdil@google.com>,
        Alexandru Elisei <alexandru.elisei@arm.com>,
        Ard Biesheuvel <ardb@kernel.org>,
        Jing Zhang <jingzhangos@google.com>,
        Ajay Patil <pajay@qti.qualcomm.com>,
        Prasad Sodagudi <psodagud@codeaurora.org>,
        James Morse <james.morse@arm.com>,
        Julien Thierry <julien.thierry.kdev@gmail.com>,
        Suzuki K Poulose <suzuki.poulose@arm.com>,
        kernel-team@android.com
References: <20210118094533.2874082-1-maz@kernel.org>
 <20210118094533.2874082-22-maz@kernel.org>
 <YAwydxY68TULznr1@Catalins-MacBook-Air.local>
From:   Srinivas Ramana <sramana@codeaurora.org>
Message-ID: <accc21e9-f987-7244-b10a-a01842a3da3c@codeaurora.org>
Date:   Tue, 26 Jan 2021 12:30:51 -0800
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Hi Marc,

On 1/23/2021 6:28 AM, Catalin Marinas wrote:
> On Mon, Jan 18, 2021 at 09:45:33AM +0000, Marc Zyngier wrote:
>> In order to be able to disable Pointer Authentication  at runtime,
>> whether it is for testing purposes, or to work around HW issues,
>> let's add support for overriding the ID_AA64ISAR1_EL1.{GPI,GPA,API,APA}
>> fields.
>>
>> This is further mapped on the arm64.nopauth command-line alias.
>>
>> Signed-off-by: Marc Zyngier <maz@kernel.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Verified this Series for PAC control feature from command line. with 
arm64.nopauth, we could see PAUTH is disabled on both primary and 
secondary cores as expected.

HWCAPs show no PAC support and kernel instructions are being treated as 
NOPs.

Tested-by: Srinivas Ramana <sramana@codeaurora.org>