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Subject: Re: [PATCH v19 00/15] arm64: untag user pointers passed to the kernel
To:     Dave Hansen <dave.hansen@intel.com>,
        Andrey Konovalov <andreyknvl@google.com>,
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Cc:     Catalin Marinas <catalin.marinas@arm.com>,
        Vincenzo Frascino <vincenzo.frascino@arm.com>,
        Will Deacon <will.deacon@arm.com>,
        Mark Rutland <mark.rutland@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Kees Cook <keescook@chromium.org>,
        Yishai Hadas <yishaih@mellanox.com>,
        Felix Kuehling <Felix.Kuehling@amd.com>,
        Alexander Deucher <Alexander.Deucher@amd.com>,
        Christian Koenig <Christian.Koenig@amd.com>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Jens Wiklander <jens.wiklander@linaro.org>,
        Alex Williamson <alex.williamson@redhat.com>,
        Leon Romanovsky <leon@kernel.org>,
        Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
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        Lee Smith <Lee.Smith@arm.com>,
        Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
        Jacob Bramley <Jacob.Bramley@arm.com>,
        Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Szabolcs Nagy <Szabolcs.Nagy@arm.com>
References: <cover.1563904656.git.andreyknvl@google.com>
 <8c618cc9-ae68-9769-c5bb-67f1295abc4e@intel.com>
From:   Kevin Brodsky <kevin.brodsky@arm.com>
Message-ID: <13b4cf53-3ecb-f7e7-b504-d77af15d77aa@arm.com>
Date:   Thu, 1 Aug 2019 13:11:40 +0100
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On 31/07/2019 17:50, Dave Hansen wrote:
> On 7/23/19 10:58 AM, Andrey Konovalov wrote:
>> The mmap and mremap (only new_addr) syscalls do not currently accept
>> tagged addresses. Architectures may interpret the tag as a background
>> colour for the corresponding vma.
> What the heck is a "background colour"? :)

Good point, this is some jargon that we started using for MTE, the idea being that 
the kernel could set a tag value (specified during mmap()) as "background colour" for 
anonymous pages allocated in that range.

Anyway, this patch series is not about MTE. Andrey, for v20 (if any), I think it's 
best to drop this last sentence to avoid any confusion.

Kevin