diff --git a/sys/arm/include/proc.h b/sys/arm/include/proc.h
index 4ffbec59d86..a86df3557cc 100644
--- a/sys/arm/include/proc.h
+++ b/sys/arm/include/proc.h
@@ -68,15 +68,20 @@ struct mdproc {
 #endif
 
 #define MAXARGS	8
+/*
+ * This holds the syscall state for a single system call.
+ * As some syscall arguments may be 64-bit aligned we need to ensure the
+ * args value is 64-bit aligned. The ABI will then ensure any 64-bit
+ * arguments are already correctly aligned, even if they were passed in
+ * via registers, we just need to make sure we copy them to an algned
+ * buffer.
+ */
 struct syscall_args {
 	u_int code;
 	struct sysent *callp;
 	register_t args[MAXARGS];
 	int narg;
 	u_int nap;
-#ifndef __ARM_EABI__
-	u_int32_t insn;
-#endif
-};
+} __aligned(8);
 
 #endif /* !_MACHINE_PROC_H_ */