RE: [PATCH v11 5/6] arm64: smp: IPI_CPU_STOP and IPI_CPU_CRASH_STOP should try for NMI
From: Tomohiro Misono (Fujitsu) <hidden>
Date: 2023-08-29 05:32:21
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-----Original Message----- There's no reason why IPI_CPU_STOP and IPI_CPU_CRASH_STOP can't be handled as NMI. They are very simple and everything in them is NMI-safe. Mark them as things to use NMI for if NMI is available. Suggested-by: Mark Rutland <mark.rutland@arm.com> Reviewed-by: Stephen Boyd <redacted> Signed-off-by: Douglas Anderson <dianders@chromium.org> --- I don't actually have any good way to test/validate this patch. It's added to the series at Mark's request.
For IPI_CPU_CRASH_STOP, I briefly checked that HARDLOCKUP-ed CPU (by lkdtm) received the ipi upon crash dump request when pseudo NMI is enabled. Reviewed-by: Misono Tomohiro [off-list ref] Regards, Tomohiro
quoted hunk ↗ jump to hunk
(no changes since v10) Changes in v10: - ("IPI_CPU_STOP and IPI_CPU_CRASH_STOP should try for NMI") new for v10. arch/arm64/kernel/smp.c | 2 ++ 1 file changed, 2 insertions(+)diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c index c8896cbc5327..4566934aaf9f 100644 --- a/arch/arm64/kernel/smp.c +++ b/arch/arm64/kernel/smp.c@@ -946,6 +946,8 @@ static bool ipi_should_be_nmi(enum ipi_msg_type ipi) return false; switch (ipi) { + case IPI_CPU_STOP: + case IPI_CPU_CRASH_STOP: case IPI_CPU_BACKTRACE: return true; default: --2.42.0.rc1.204.g551eb34607-goog _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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