Re: [PATCH v13 4/7] arm64: mte: Enable TCO in functions that can read beyond buffer limits
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-02-23 12:09:07
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On Tue, Feb 23, 2021 at 10:56:46AM +0000, Vincenzo Frascino wrote:
On 2/22/21 5:58 PM, Catalin Marinas wrote:quoted
We'll still have an issue with dynamically switching the async/sync mode at run-time. Luckily kasan doesn't do this now. The problem is that until the last CPU have been switched from async to sync, we can't toggle the static label. When switching from sync to async, we need to do it on the first CPU being switched.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.
Probably it is worth to discuss it further once we cross that bridge.
Yes. For now, a warning should do so that we don't forget. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel