[PATCH v10 5/6] arm64: smp: IPI_CPU_STOP and IPI_CPU_CRASH_STOP should try for NMI

From: Douglas Anderson
Date: Tue Aug 22 2023 - 17:31:05 EST


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>
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
I don't actually have any good way to test/validate this patch. It's
added to the series at Mark's request.

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 15b66dc1391b..c51d54019f5f 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