From: David Kaplan <david.kaplan@amd.com>

Add a function to send an NMI-to-self which is needed for stop-machine
NMI facility. Note that send_IPI_self() cannot be used to send an NMI so
send_IPI() is used.

Signed-off-by: David Kaplan <david.kaplan@amd.com>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
---
V1 -> V2: Fix a typo (Thomas) and wrap it under the new build option
---
 arch/x86/kernel/apic/ipi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/arch/x86/kernel/apic/ipi.c b/arch/x86/kernel/apic/ipi.c
index 98a57cb4aa86..597f03192a49 100644
--- a/arch/x86/kernel/apic/ipi.c
+++ b/arch/x86/kernel/apic/ipi.c
@@ -4,6 +4,7 @@
 #include <linux/delay.h>
 #include <linux/smp.h>
 #include <linux/string_choices.h>
+#include <linux/stop_machine.h>
 
 #include <asm/io_apic.h>
 
@@ -248,6 +249,15 @@ void default_send_IPI_self(int vector)
 	__default_send_IPI_shortcut(APIC_DEST_SELF, vector);
 }
 
+#ifdef CONFIG_STOP_MACHINE_NMI
+
+void arch_send_self_nmi(void)
+{
+	apic->send_IPI(smp_processor_id(), NMI_VECTOR);
+}
+
+#endif
+
 #ifdef CONFIG_X86_32
 void default_send_IPI_mask_sequence_logical(const struct cpumask *mask, int vector)
 {
-- 
2.51.0