Re: [PATCH RESEND v7 02/21] drivers/perf: apple_m1: Only init PMUv3 remap when EL2 is available
From: Nick Chan <hidden>
Date: 2025-07-14 15:37:53
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Will Deacon 於 2025/7/14 夜晚11:11 寫道:
On Mon, Jun 16, 2025 at 09:31:51AM +0800, Nick Chan wrote:quoted
Skip initialization of PMUv3 remap when EL2 is not available. Initialization is harmless in EL1 but it is still a weird thing to do.Why is that weird?
Maybe I could use better wording but if the check is not here, then for Apple A7 which has very different event mappings, it either has to use the mappings for M1 which is wrong on the hardware, or declare an a7_pmu_pmceid_map, which would just be dead code since A7's CPU does not support EL2. Not initializing the mapping in EL1 avoid these problems.
Will
Nick Chan