diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 8363ad3..c48bc2e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1859,6 +1859,9 @@
 			vdso=1: enable VDSO (default)
 			vdso=0: disable VDSO mapping
 
+	vector=		[IA-64,SMP]
+			vector=percpu: enable percpu vector domain
+
 	video=		[FB] Frame buffer configuration
 			See Documentation/fb/modedb.txt.