x86/kprobes: Prohibit probing on optprobe template code

x86/kprobes: Prohibit probing on optprobe template code

Prohibit probing on optprobe template code, since it is not
a code but a template instruction sequence. If we modify
this template, copied template must be broken.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andrea Righi <righi.andrea@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Fixes: 2893f2d079a9 ("kprobes, x86: Use NOKPROBE_SYMBOL() instead of __kprobes annotation")
Link: http://lkml.kernel.org/r/154998787911.31052.15274376330136234452.stgit@devbox
Signed-off-by: Ingo Molnar <mingo@kernel.org>