x86/kprobes: Make trampoline_handler() global and visible

This function is referenced from assembler, so in LTO
it needs to be global and visible to not be optimized away.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20190330004743.29541-7-andi@firstfloor.orgSigned-off-by: Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/kprobes/core.c

@@ -768,7 +768,7 @@ static struct kprobe kretprobe_kprobe = {
 /*
  * Called from kretprobe_trampoline
  */
-static __used void *trampoline_handler(struct pt_regs *regs)
+__used __visible void *trampoline_handler(struct pt_regs *regs)
 {
 	struct kprobe_ctlblk *kcb;
 	struct kretprobe_instance *ri = NULL;