diff --git a/sys/arm64/include/db_machdep.h b/sys/arm64/include/db_machdep.h
--- a/sys/arm64/include/db_machdep.h
+++ b/sys/arm64/include/db_machdep.h
@@ -38,6 +38,7 @@
 #include <machine/trap.h>
 
 #define	T_BREAKPOINT	(EXCP_BRK)
+#define	T_SINGLESTEP	(EXCP_SOFTSTP_EL1)
 #define	T_WATCHPOINT	(EXCP_WATCHPT_EL1)
 
 typedef vm_offset_t	db_addr_t;
@@ -58,6 +59,7 @@
 #define	db_set_single_step	kdb_cpu_set_singlestep
 
 #define	IS_BREAKPOINT_TRAP(type, code)	(type == T_BREAKPOINT)
+#define	IS_SSTEP_TRAP(type, code)	(type == T_SINGLESTEP)
 #define	IS_WATCHPOINT_TRAP(type, code)	(type == T_WATCHPOINT)
 
 #define	inst_trap_return(ins)	(0)