Re: [PATCH v12 6/7] arm64: mte: Save/Restore TFSR_EL1 during suspend
From: Catalin Marinas <catalin.marinas@arm.com>
Date: 2021-02-09 11:58:49
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On Mon, Feb 08, 2021 at 04:56:16PM +0000, Vincenzo Frascino wrote:
When MTE async mode is enabled TFSR_EL1 contains the accumulative asynchronous tag check faults for EL1 and EL0. During the suspend/resume operations the firmware might perform some operations that could change the state of the register resulting in a spurious tag check fault report. Save/restore the state of the TFSR_EL1 register during the suspend/resume operations to prevent this to happen.
Do we need a similar fix for TFSRE0_EL1? We get away with this if suspend is only entered on the idle (kernel) thread but I recall we could also enter suspend on behalf of a user process (I may be wrong though). If that's the case, it would make more sense to store the TFSR* regs in the thread_struct alongside sctlr_tcf0. If we did that, we'd not need the per-cpu mte_suspend_tfsr_el1 variable. -- Catalin _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel