Index: head/sys/arm64/arm64/gic_v3_its.c
===================================================================
--- head/sys/arm64/arm64/gic_v3_its.c
+++ head/sys/arm64/arm64/gic_v3_its.c
@@ -180,6 +180,19 @@
 	sc = device_get_softc(dev);
 
 	/*
+	 * XXX ARM64TODO: Avoid configuration of more than one ITS
+	 * device. To be removed when multi-PIC support is added
+	 * to FreeBSD (or at least multi-ITS is implemented). Limit
+	 * supported ITS sockets to '0' only.
+	 */
+	if (device_get_unit(dev) != 0) {
+		device_printf(dev,
+		    "Only single instance of ITS is supported, exitting...\n");
+		return (ENXIO);
+	}
+	sc->its_socket = 0;
+
+	/*
 	 * Initialize sleep & spin mutex for ITS
 	 */
 	/* Protects ITS device list and assigned LPIs bitmaps. */
@@ -558,6 +571,10 @@
 			sc = its_sc;
 		} else
 			return (ENXIO);
+
+		/* Skip if running secondary init on a wrong socket */
+		if (sc->its_socket != CPU_CURRENT_SOCKET)
+			return (ENXIO);
 	}
 
 	/*
Index: head/sys/arm64/arm64/gic_v3_var.h
===================================================================
--- head/sys/arm64/arm64/gic_v3_var.h
+++ head/sys/arm64/arm64/gic_v3_var.h
@@ -232,6 +232,8 @@
 
 	struct mtx		its_mtx;
 	struct mtx		its_spin_mtx;
+
+	uint32_t		its_socket;	/* Socket number ITS is attached to */
 };
 
 /* Stuff that is specific to the vendor's implementation */
Index: head/sys/arm64/include/cpu.h
===================================================================
--- head/sys/arm64/include/cpu.h
+++ head/sys/arm64/include/cpu.h
@@ -148,6 +148,8 @@
 void	swi_vm(void *v);
 
 #define	CPU_AFFINITY(cpu)	__cpu_affinity[(cpu)]
+#define	CPU_CURRENT_SOCKET				\
+    (CPU_AFF2(CPU_AFFINITY(PCPU_GET(cpuid))))
 
 static __inline uint64_t
 get_cyclecount(void)