Managing and Developing Dynamically Loadable Kernel Modules

Developing Dynamically Loadable Kernel Modules

Chapter 12554

NOTE The ﬁle locations receiving copies of the module’s component ﬁles may

change in future HP-UX releases.

Activating the DLKM

After a module’s component ﬁles have been installed using the kminstall

command, the module is ready to be conﬁgured and registered with the

running kernel. Follow the procedures in “DLKM Procedures for

Dynamically Conﬁgured Loadable Modules” on page 511 for instructions

on how to prepare, conﬁgure, register, load, and manage your DLKM as

dynamically loadable, on the target system.

To conﬁgure and test your DLKM as statically linked refer to “DLKM

Procedures for Statically Conﬁgured Loadable Modules” on page 518.

Creating Device Special Files for the Module

Before devices supported by a driver type DLKM module can be accessed

by the system, you need to create special ﬁles in the /dev directory using

the mknod (1M) command. You do not have to create these ﬁles every

time you build and boot a new kernel--only when you ﬁrst add the new

module. There must be a special ﬁle for each device on your system.

When you set up the special ﬁles for a newly added device driver, you

must specify the device type (character or block) and the major and

minor device numbers. The kernel recognizes any single device by the

major-minor number combination encoded in the device special ﬁles.

For a dynamically loadable driver, the system assigns a major number to

the driver when it ﬁrst registers with the system. For a statically linked

driver, the system assigns a major number to the driver during system

boot. The system remembers assigned major numbers from system boot

to system boot.

To have the system dynamically assign a major number to your driver,

follow these steps:

1. Specify -1 in both the block major and char major ﬁelds in the

$DRIVER_INSTALL section of your driver’s master ﬁle.

2. Specify -1 in both the b_major and c_major ﬁelds of the drv_info_t

structure of your driver source code.