Index: head/sys/amd64/amd64/machdep.c
===================================================================
--- head/sys/amd64/amd64/machdep.c
+++ head/sys/amd64/amd64/machdep.c
@@ -1621,6 +1621,7 @@
 	mtx_init(&dt_lock, "descriptor tables", NULL, MTX_DEF);
 
 	/* exceptions */
+	pti = pti_get_default();
 	TUNABLE_INT_FETCH("vm.pmap.pti", &pti);
 
 	for (x = 0; x < NIDT; x++)
Index: head/sys/x86/include/x86_var.h
===================================================================
--- head/sys/x86/include/x86_var.h
+++ head/sys/x86/include/x86_var.h
@@ -136,6 +136,7 @@
 void	nmi_handle_intr(u_int type, struct trapframe *frame);
 void	pagecopy(void *from, void *to);
 void	printcpuinfo(void);
+int	pti_get_default(void);
 int	user_dbreg_trap(void);
 int	minidumpsys(struct dumperinfo *);
 struct pcb *get_pcb_td(struct thread *td);
Index: head/sys/x86/x86/identcpu.c
===================================================================
--- head/sys/x86/x86/identcpu.c
+++ head/sys/x86/x86/identcpu.c
@@ -1608,6 +1608,16 @@
 #endif
 }
 
+int
+pti_get_default(void)
+{
+
+	if (strcmp(cpu_vendor, AMD_VENDOR_ID) == 0)
+		return (0);
+
+	return (1);
+}
+
 static u_int
 find_cpu_vendor_id(void)
 {