Re: [PATCH v11 5/6] arm64: smp: IPI_CPU_STOP and IPI_CPU_CRASH_STOP should try for NMI

[Sumit Garg]

On Thu, 24 Aug 2023 at 21:03, Douglas Anderson <dianders@xxxxxxxxxxxx> 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@xxxxxxx>
> Reviewed-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
> Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>

Reviewed-by: Sumit Garg <sumit.garg@xxxxxxxxxx>

-Sumit

> ---
> I don't actually have any good way to test/validate this patch. It's
> added to the series at Mark's request.
>
> (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
>