diff --git a/arch/powerpc/kernel/smp.c b/arch/powerpc/kernel/smp.c
index 265801a3e94c..406e6d0ffae3 100644
--- a/arch/powerpc/kernel/smp.c
+++ b/arch/powerpc/kernel/smp.c
@@ -291,7 +291,7 @@ void smp_muxed_ipi_set_message(int cpu, int msg)
 	 * Order previous accesses before accesses in the IPI handler.
 	 */
 	smp_mb();
-	message[msg] = 1;
+	WRITE_ONCE(message[msg], 1);
 }
 
 void smp_muxed_ipi_message_pass(int cpu, int msg)
@@ -350,7 +350,7 @@ irqreturn_t smp_ipi_demux_relaxed(void)
 		if (all & IPI_MESSAGE(PPC_MSG_NMI_IPI))
 			nmi_ipi_action(0, NULL);
 #endif
-	} while (info->messages);
+	} while (READ_ONCE(info->messages));
 
 	return IRQ_HANDLED;
 }