diff --git a/sys/amd64/include/specialreg.h b/sys/amd64/include/specialreg.h
index fa7b1608d48c..143026b0be44 100644
--- a/sys/amd64/include/specialreg.h
+++ b/sys/amd64/include/specialreg.h
@@ -123,6 +123,7 @@
 #define	CPUID2_CNXTID	0x00000400
 #define	CPUID2_CX16	0x00002000
 #define	CPUID2_XTPR	0x00004000
+#define	CPUID2_PDCM	0x00008000
 #define	CPUID2_DCA	0x00040000
 
 /*
diff --git a/sys/i386/include/specialreg.h b/sys/i386/include/specialreg.h
index 9fa01eed721b..a210bc41178e 100644
--- a/sys/i386/include/specialreg.h
+++ b/sys/i386/include/specialreg.h
@@ -120,6 +120,7 @@
 #define	CPUID2_CNXTID	0x00000400
 #define	CPUID2_CX16	0x00002000
 #define	CPUID2_XTPR	0x00004000
+#define	CPUID2_PDCM	0x00008000
 #define	CPUID2_DCA	0x00040000
 
 /*