Re: [PATCH v2] clocksource/arm_arch_timer: Fix masking for high freq counters
From: Oliver Upton <hidden>
Date: 2021-08-08 19:01:27
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On Sun, Aug 8, 2021 at 3:40 AM Marc Zyngier [off-list ref] wrote:
On Sun, 08 Aug 2021 02:14:35 +0100, Oliver Upton [off-list ref] wrote:quoted
The only other sane idea that I could come up with is providing this information to the kernel through DT, although that would leave ACPI systems behind.It also has the disadvantage that a large number of DT timer nodes are a mess of cargo-culted, copy-pasted idioms, and that adding another property would only make it worse.
Agreed, this does seem like the best solution, short of the architecture actually providing something to determine the counter width. On that note, I wonder how (if ever) we will be able to move away from unnecessarily masking a 64 bit counter, i.e. a v8.6 or above implementation. With this patch, one such counter would wrap after 36.56 years, short of the 40 year guarantee we have from the architecture for < v8.6 implementations. Getting it to 64 bits would squarely make it someone else's problem ~585 years from now :) -- Thanks, Oliver _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel