Managing and Developing Dynamically Loadable Kernel Modules

Managing and Developing Dynamically Loadable Kernel Modules
Developing Dynamically Loadable Kernel Modules
Chapter 12 537
whether, and/or when, to load the module upon a system reboot. It
can be one of the following:
A Auto
1 Phase 1 of the boot sequence
2 Phase 2 of the boot sequence
I Init phase
Absence of this section indicates that the module will be configured to
be loaded only on demand or by the auto loading mechanism. This is
equivalent to specifying:
$LOADPHASE A
❏ $TUNABLE (empty) – place holder for any tunable parameter specified
in the associated master file for which you want to specify a value
other than the default value. Leave this section blank.
kmtune (1M) is the interface to modify tunable parameters in the
module's system description file and the HP-UX system file (/stand/
system by default).
For complete details on the use of these keywords, see the “Modular
System File” section of the system (4) manpage.
space.h File Definition
An optional component, the space.h file contains storage allocations and
initializations of data structures associated with a DLKM module when
the size or initial value of the data structures depend on configurable
values such as tunable parameters. In order to communicate these values
to the rest of the DLKM module, the values are stored in global variables
and accessed by the module via extern declarations in the module’s
mod.o file.
NOTE All tunable parameters specified in the master file are defined as global
variables in the space.h file. See “Sample DLKM WSIO Class Driver” on
page 558 for clarification.