Generalised Kernel Hooks Interface - A High Speed Call-back Mechanism for
the Linux Kernel

Generalised Kernel Hooks Interface (GKHI) is a generalised facility for
placing hooks in arbitrary kernel (or kernel module) locations. A hook a
location in the
kernel that calls out of the kernel to a kernel module routine - a hook
exit. It enables many kernel enhancements, which are otherwise
self-contained, to become
loadable kernel modules and retain a substantial degree of independence
from the kernel source. This affords advantages for maintenance and
co-existence with
other kernel enhancements.

The hooks are implemented as fast and slim-line insertions to kernel code
when not active, with practically no overhead to the kernel.

The hook interface allows multiple kernel modules to register their exits
for a given hook, in order to receive control at that given hook location.

A particularly interesting application of GKHI is in dynamic assertion
checking and First Failure System Technology (FFST).