diff --git a/sys/arm64/arm64/swtch.S b/sys/arm64/arm64/swtch.S
--- a/sys/arm64/arm64/swtch.S
+++ b/sys/arm64/arm64/swtch.S
@@ -270,9 +270,7 @@
 	/* Store the VFP registers */
 #ifdef VFP
 	mov	x28, lr
-	mov	x1, x0			/* move pcb to the correct register */
-	mov	x0, xzr			/* td = NULL */
-	bl	vfp_save_state
+	bl	vfp_save_state_savectx
 	mov	lr, x28
 #endif
 
diff --git a/sys/arm64/arm64/vfp.c b/sys/arm64/arm64/vfp.c
--- a/sys/arm64/arm64/vfp.c
+++ b/sys/arm64/arm64/vfp.c
@@ -166,25 +166,11 @@
 	    : : "r"(fpcr), "r"(fpsr), "r"(vfp_state));
 }
 
-void
-vfp_save_state(struct thread *td, struct pcb *pcb)
+static void
+vfp_save_state_common(struct thread *td, struct pcb *pcb)
 {
 	uint32_t cpacr;
 
-	KASSERT(pcb != NULL, ("NULL vfp pcb"));
-	KASSERT(td == NULL || td->td_pcb == pcb, ("Invalid vfp pcb"));
-
-	/* 
-	 * savectx() will be called on panic with dumppcb as an argument,
-	 * dumppcb doesn't have pcb_fpusaved set, so set it to save
-	 * the VFP registers.
-	 */
-	if (pcb->pcb_fpusaved == NULL)
-		pcb->pcb_fpusaved = &pcb->pcb_fpustate;
-
-	if (td == NULL)
-		td = curthread;
-
 	critical_enter();
 	/*
 	 * Only store the registers if the VFP is enabled,
@@ -202,6 +188,30 @@
 	critical_exit();
 }
 
+void
+vfp_save_state(struct thread *td, struct pcb *pcb)
+{
+	KASSERT(td != NULL, ("NULL vfp thread"));
+	KASSERT(pcb != NULL, ("NULL vfp pcb"));
+	KASSERT(td->td_pcb == pcb, ("Invalid vfp pcb"));
+
+	vfp_save_state_common(td, pcb);
+}
+
+void
+vfp_save_state_savectx(struct pcb *pcb)
+{
+	/*
+	 * savectx() will be called on panic with dumppcb as an argument,
+	 * dumppcb doesn't have pcb_fpusaved set, so set it to save
+	 * the VFP registers.
+	 */
+	MPASS(pcb->pcb_fpusaved == NULL);
+	pcb->pcb_fpusaved = &pcb->pcb_fpustate;
+
+	vfp_save_state_common(curthread, pcb);
+}
+
 /*
  * Update the VFP state for a forked process or new thread. The PCB will
  * have been copied from the old thread.
diff --git a/sys/arm64/include/vfp.h b/sys/arm64/include/vfp.h
--- a/sys/arm64/include/vfp.h
+++ b/sys/arm64/include/vfp.h
@@ -78,6 +78,7 @@
 void	vfp_reset_state(struct thread *, struct pcb *);
 void	vfp_restore_state(void);
 void	vfp_save_state(struct thread *, struct pcb *);
+void	vfp_save_state_savectx(struct pcb *);
 
 struct fpu_kern_ctx;