In normal operation, kretprobe makes a target function return to trampoline
code.  A kprobe (called trampoline_probe) has been inserted in the trampoline
code.  When the kernel hits this kprobe, it calls kretprobe's handler and it
returns to the original return address.

Kretprobe-booster removes the trampoline_probe.  It allows the trampoline code
to call kretprobe's handler directly instead of invoking kprobe.  The
trampoline code returns to the original return address.

(changelog from Chuck Ebbert <76306.1226@compuserve.com> - thanks ;))

Signed-off-by: Masami Hiramatsu <hiramatu@sdl.hitachi.co.jp>
Cc: Prasanna S Panchamukhi <prasanna@in.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Chuck Ebbert <76306.1226@compuserve.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>