Managing and Developing Dynamically Loadable Kernel Modules

Managing Dynamically Loadable Kernel Modules

Chapter 12494

What is DLKM

The Dynamically Loadable Kernel Modules Infrastructure is an HP-UX

operating system feature that allows “DLKM-Enabled” kernel modules

to be dynamically loaded into, or unloaded from, the HP-UX kernel

without having to re-link the entire kernel or reboot the system.

Previously, to install and use a new driver, you had to edit the system

ﬁle, run the config or mk_kernel commands to create a new kernel,

shut down the system, and then bring the system back up.

The DLKM feature not only provides the infrastructure to load kernel

modules into a running system, but it also allows you the option of

statically linking a kernel module when rebuilding the kernel. This is

accomplished by changing the value of one of the DLKM module’s

conﬁguration attributes.

Important Terms and Concepts The DLKM infrastructure allows

kernel modules to be conﬁgured in a number of different ways. The

following table considers the different ways a kernel module can be

conﬁgured and loaded, and clearly deﬁnes each. It also clariﬁes the

relationship between each term as seen by the HP-UX kernel.

Table 12-1 Important Terms and Concepts

Term /

Concept

Deﬁnition

Kernel

Module

A Kernel Module is a section of kernel code

responsible for supporting a speciﬁc capability or

feature. For example, ﬁle system types and device

drivers are kernel modules.

In the kernel conﬁguration context, a kernel module

may be viewed as an object that can be added and/or

removed from the kernel, either statically or

dynamically.

There are two categories of kernel modules:

• Traditional Module

• Modularly Packaged Module