Re: [PATCH v12 5/7] arm64: smp: IPI_CPU_STOP and IPI_CPU_CRASH_STOP should try for NMI
From: Mark Rutland <mark.rutland@arm.com>
Date: 2023-08-31 10:12:54
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On Wed, Aug 30, 2023 at 12:11:26PM -0700, Douglas Anderson wrote:
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> Reviewed-by: Misono Tomohiro <redacted> Reviewed-by: Sumit Garg <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.
I've just sent out an LKDTM test that can be used to test this: http://lore.kernel.org/lkml/20230831101026.3122590-1-mark.rutland@arm.com (local) So FWIW: Acked-by: Mark Rutland <mark.rutland@arm.com> Tested-by: Mark Rutland <mark.rutland@arm.com> Mark.
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 28c904ca499a..800c59cf9b64 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:-- 2.42.0.283.g2d96d420d3-goog
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