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From: Vincenzo Frascino <vincenzo.frascino@arm.com>
To: Will Deacon <will@kernel.org>, Catalin Marinas <catalin.marinas@arm.com>
Cc: linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, kasan-dev@googlegroups.com,
	Andrew Morton <akpm@linux-foundation.org>,
	Dmitry Vyukov <dvyukov@google.com>,
	Andrey Ryabinin <aryabinin@virtuozzo.com>,
	Alexander Potapenko <glider@google.com>,
	Marco Elver <elver@google.com>,
	Evgenii Stepanov <eugenis@google.com>,
	Branislav Rankov <Branislav.Rankov@arm.com>,
	Andrey Konovalov <andreyknvl@google.com>,
	Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Subject: Re: [PATCH v13 4/7] arm64: mte: Enable TCO in functions that can read beyond buffer limits
Date: Tue, 23 Feb 2021 14:25:14 +0000	[thread overview]
Message-ID: <bf45cf22-662b-e99c-4868-bfc64a0622b0@arm.com> (raw)
In-Reply-To: <20210223124951.GA10563@willie-the-truck>

On 2/23/21 12:49 PM, Will Deacon wrote:
>>> I totally agree on this point. In the case of runtime switching we might need
>>> the rethink completely the strategy and depends a lot on what we want to allow
>>> and what not. For the kernel I imagine we will need to expose something in sysfs
>>> that affects all the cores and then maybe stop_machine() to propagate it to all
>>> the cores. Do you think having some of the cores running in sync mode and some
>>> in async is a viable solution?
>> stop_machine() is an option indeed. I think it's still possible to run
>> some cores in async while others in sync but the static key here would
>> only be toggled when no async CPUs are left.
> Just as a general point, but if we expose stop_machine() via sysfs we
> probably want to limit that to privileged users so you can't DoS the system
> by spamming into the file.

I agree, if we ever introduce the runtime switching and go for this option we
should make sure that we do it safely.

-- 
Regards,
Vincenzo

  parent reply	other threads:[~2021-02-23 14:22 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-11 15:33 [PATCH v13 0/7] arm64: ARMv8.5-A: MTE: Add async mode support Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 1/7] arm64: mte: Add asynchronous " Vincenzo Frascino
2021-02-12 21:21   ` Andrey Konovalov
2021-02-22 11:14     ` Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 2/7] kasan: Add KASAN mode kernel parameter Vincenzo Frascino
2021-02-11 17:50   ` Andrey Konovalov
2021-02-12 11:26     ` Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 3/7] kasan: Add report for async mode Vincenzo Frascino
2021-02-11 20:03   ` kernel test robot
2021-02-11 20:13     ` Andrey Konovalov
2021-02-12 11:25       ` Vincenzo Frascino
2021-02-12 14:47         ` Andrey Konovalov
2021-02-11 23:03   ` kernel test robot
2021-02-11 15:33 ` [PATCH v13 4/7] arm64: mte: Enable TCO in functions that can read beyond buffer limits Vincenzo Frascino
2021-02-12 17:21   ` Catalin Marinas
2021-02-22 12:08     ` Vincenzo Frascino
2021-02-22 17:58       ` Catalin Marinas
2021-02-23 10:56         ` Vincenzo Frascino
2021-02-23 12:05           ` Catalin Marinas
2021-02-23 12:22             ` Vincenzo Frascino
2021-02-23 12:49             ` Will Deacon
2021-02-23 13:14               ` Catalin Marinas
2021-02-23 14:25               ` Vincenzo Frascino [this message]
2021-02-11 15:33 ` [PATCH v13 5/7] arm64: mte: Enable async tag check fault Vincenzo Frascino
2021-02-11 15:33 ` [PATCH v13 6/7] arm64: mte: Report async tag faults before suspend Vincenzo Frascino
2021-02-12 12:00   ` Lorenzo Pieralisi
2021-02-12 12:30     ` Lorenzo Pieralisi
2021-02-12 13:05       ` Vincenzo Frascino
2021-02-12 13:19     ` Catalin Marinas
2021-02-12 17:24   ` Catalin Marinas
2021-02-11 15:33 ` [PATCH v13 7/7] kasan: don't run tests in async mode Vincenzo Frascino
2021-02-12  0:49   ` kernel test robot
2021-02-12 17:22   ` Catalin Marinas
2021-02-12 21:44     ` Andrey Konovalov
2021-02-22 11:17       ` Vincenzo Frascino
2021-02-22 13:35         ` Andrey Konovalov
2021-02-11 15:45 ` [PATCH v13 0/7] arm64: ARMv8.5-A: MTE: Add async mode support Vincenzo Frascino

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