diff --git a/sys/conf/files.arm64 b/sys/conf/files.arm64
--- a/sys/conf/files.arm64
+++ b/sys/conf/files.arm64
@@ -419,6 +419,8 @@
 
 dev/psci/psci.c					standard
 dev/psci/smccc_arm64.S				standard
+dev/psci/smccc_kmsan.c				optional kmsan \
+	compile-with "${NOSAN_C}"
 dev/psci/smccc_trng.c				standard
 dev/psci/smccc.c				standard
 
diff --git a/sys/dev/psci/smccc.h b/sys/dev/psci/smccc.h
--- a/sys/dev/psci/smccc.h
+++ b/sys/dev/psci/smccc.h
@@ -87,10 +87,21 @@
 int smccc_arch_workaround_1(void);
 int smccc_arch_workaround_2(int);
 
+#if defined(SAN_NEEDS_INTERCEPTORS) && !defined(SMCCC_SAN_RUNTIME)
+int SAN_INTERCEPTOR(arm_smccc_smc)(register_t, register_t, register_t,
+    register_t, register_t, register_t, register_t, register_t,
+    struct arm_smccc_res *res);
+int SAN_INTERCEPTOR(arm_smccc_hvc)(register_t, register_t, register_t,
+    register_t, register_t, register_t, register_t, register_t,
+    struct arm_smccc_res *res);
+#define	arm_smccc_smc	SAN_INTERCEPTOR(arm_smccc_smc)
+#define	arm_smccc_hvc	SAN_INTERCEPTOR(arm_smccc_hvc)
+#else
 int arm_smccc_smc(register_t, register_t, register_t, register_t, register_t,
     register_t, register_t, register_t, struct arm_smccc_res *res);
 int arm_smccc_hvc(register_t, register_t, register_t, register_t, register_t,
     register_t, register_t, register_t, struct arm_smccc_res *res);
+#endif
 
 #define	arm_smccc_invoke_1(func, a0, res)				\
     func(a0,  0,  0,  0,  0,  0,  0,  0, res)
diff --git a/sys/dev/psci/smccc_kmsan.c b/sys/dev/psci/smccc_kmsan.c
new file mode 100644
--- /dev/null
+++ b/sys/dev/psci/smccc_kmsan.c
@@ -0,0 +1,60 @@
+/*-
+ * SPDX-License-Identifier: BSD-2-Clause
+ *
+ * Copyright (c) 2024 Arm Ltd
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
+ */
+
+#define SMCCC_SAN_RUNTIME
+
+#include <sys/param.h>
+#include <sys/systm.h>
+#include <sys/msan.h>
+
+#include <dev/psci/psci.h>
+#include <dev/psci/smccc.h>
+
+int kmsan_arm_smccc_smc(register_t, register_t, register_t, register_t,
+    register_t, register_t, register_t, register_t, struct arm_smccc_res *);
+int kmsan_arm_smccc_hvc(register_t, register_t, register_t, register_t,
+    register_t, register_t, register_t, register_t, struct arm_smccc_res *);
+
+int
+kmsan_arm_smccc_smc(register_t a0, register_t a1, register_t a2,
+    register_t a3, register_t a4, register_t a5, register_t a6, register_t a7,
+    struct arm_smccc_res *res)
+{
+	if (res != NULL)
+		kmsan_mark(res, sizeof(*res), KMSAN_STATE_INITED);
+	return (arm_smccc_smc(a0, a1, a2, a3, a4, a5, a6, a7, res));
+}
+
+int
+kmsan_arm_smccc_hvc(register_t a0, register_t a1, register_t a2,
+    register_t a3, register_t a4, register_t a5, register_t a6, register_t a7,
+    struct arm_smccc_res *res)
+{
+	if (res != NULL)
+		kmsan_mark(res, sizeof(*res), KMSAN_STATE_INITED);
+	return (arm_smccc_hvc(a0, a1, a2, a3, a4, a5, a6, a7, res));
+}