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Date:   Thu, 17 Sep 2020 18:06:01 +0100
From:   Catalin Marinas <catalin.marinas@arm.com>
To:     Andrey Konovalov <andreyknvl@google.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        kasan-dev@googlegroups.com,
        Andrey Ryabinin <aryabinin@virtuozzo.com>,
        Alexander Potapenko <glider@google.com>,
        Marco Elver <elver@google.com>,
        Evgenii Stepanov <eugenis@google.com>,
        Elena Petrova <lenaptr@google.com>,
        Branislav Rankov <Branislav.Rankov@arm.com>,
        Kevin Brodsky <kevin.brodsky@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 26/37] arm64: mte: Convert gcr_user into an exclude
 mask
Message-ID: <20200917170601.GO10662@gaia>
References: <cover.1600204505.git.andreyknvl@google.com>
 <dbe7d509102cbbefe0bafb38e9367b5b323bfebd.1600204505.git.andreyknvl@google.com>
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On Tue, Sep 15, 2020 at 11:16:08PM +0200, Andrey Konovalov wrote:
> From: Vincenzo Frascino <vincenzo.frascino@arm.com>
> 
> The gcr_user mask is a per thread mask that represents the tags that are
> excluded from random generation when the Memory Tagging Extension is
> present and an 'irg' instruction is invoked.
> 
> gcr_user affects the behavior on EL0 only.
> 
> Currently that mask is an include mask and it is controlled by the user
> via prctl() while GCR_EL1 accepts an exclude mask.
> 
> Convert the include mask into an exclude one to make it easier the
> register setting.
> 
> Note: This change will affect gcr_kernel (for EL1) introduced with a
> future patch.
> 
> Signed-off-by: Vincenzo Frascino <vincenzo.frascino@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>