x86/xen: Mark xen_force_evtchn_callback() noinstr

vmlinux.o: warning: objtool: check_events()+0xd: call to xen_force_evtchn_callback() leaves .noinstr.text section
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Juergen Gross <jgross@suse.com>
Link: https://lore.kernel.org/r/20210624095148.996055323@infradead.org

arch/x86/include/asm/xen/hypercall.h

@@ -358,7 +358,7 @@ HYPERVISOR_event_channel_op(int cmd, void *arg)
 	return _hypercall2(int, event_channel_op, cmd, arg);
 }
 
-static inline int
+static __always_inline int
 HYPERVISOR_xen_version(int cmd, void *arg)
 {
 	return _hypercall2(int, xen_version, cmd, arg);

arch/x86/xen/irq.c

@@ -19,7 +19,7 @@
  * callback mask. We do this in a very simple manner, by making a call
  * down into Xen. The pending flag will be checked by Xen on return.
  */
-void xen_force_evtchn_callback(void)
+noinstr void xen_force_evtchn_callback(void)
 {
 	(void)HYPERVISOR_xen_version(0, NULL);
 }