Index: head/sys/amd64/amd64/cpu_switch.S
===================================================================
--- head/sys/amd64/amd64/cpu_switch.S
+++ head/sys/amd64/amd64/cpu_switch.S
@@ -209,14 +209,11 @@
 done_tss:
 	movq	%r8,PCPU(RSP0)
 	movq	%r8,PCPU(CURPCB)
-	/* Update the TSS_RSP0 pointer for the next interrupt */
-	cmpq	$~0,PCPU(UCR3)
-	je	1f
 	movq	PCPU(PTI_RSP0),%rax
+	cmpq	$~0,PCPU(UCR3)
+	cmove	%r8,%rax
 	movq	%rax,TSS_RSP0(%rdx)
-	jmp	2f
-1:	movq	%r8,TSS_RSP0(%rdx)
-2:	movq	%r12,PCPU(CURTHREAD)		/* into next thread */
+	movq	%r12,PCPU(CURTHREAD)		/* into next thread */
 
 	/* Test if debug registers should be restored. */
 	testl	$PCB_DBREGS,PCB_FLAGS(%r8)