kprobes/x86: Disable optimizing on the function jumps to indirect thunk

kprobes/x86: Disable optimizing on the function jumps to indirect thunk

commit c86a32c09f8ced67971a2310e3b0dda4d1749007 upstream.

Since indirect jump instructions will be replaced by jump
to __x86_indirect_thunk_*, those jmp instruction must be
treated as an indirect jump. Since optprobe prohibits to
optimize probes in the function which uses an indirect jump,
it also needs to find out the function which jump to
__x86_indirect_thunk_* and disable optimization.

Add a check that the jump target address is between the
__indirect_thunk_start/end when optimizing kprobe.

Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: David Woodhouse <dwmw@amazon.co.uk>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linux-foundation.org>
Link: https://lkml.kernel.org/r/151629212062.10241.6991266100233002273.stgit@devbox
[bwh: Backported to 3.2:
 - Include  __kprobes in both function declarations
 - Adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>