Managing and Developing Dynamically Loadable Kernel Modules

Developing Dynamically Loadable Kernel Modules

Chapter 12552

aware that a subsequent kmupdate(1M) will again overwrite the

vmunix.prev kernel.

The recommended way to permanently save /stand/vmunix is to move it

to a safe name, such as /stand/vmunix.bkup.

Do Not Copy!: Copying the /stand/vmunix ﬁle may result in the

eventual loss of the kernel component set necessary to boot the copy.

Furthermore, if /stand/vmunix had been the running kernel, we

recommend an immediate reboot from the renamed location:

#mv /stand/vmunix /stand/vmunix.bkup

#shutdown -r

Once /stand/vmunix has been moved, there is no longer a default kernel

from which to boot until a new kernel is conﬁgured and updated via the

kmupdate(1M) command. To boot from a non-default kernel, refer to

“Booting from an Alternate Kernel” in the chapter “Administering a

System: Booting and Shutdown” in Managing Systems and Workgroups.

Creating the Module’s Component Files

Create the mod.o, master, system, space.h (optional), and Modstub.o

(optional) ﬁles for the DLKM module in a single directory. It is suggested

that you use a subdirectory of /usr/conf such as /usr/conf/

module_name

When choosing a name for your module, choose a unique name to avoid

conﬂict with kernel functions and global variables. Consider using your

company’s name and something that indicates the module’s purpose.

To compile your module source code, use the ANSI C compiler /opt/

ansic/bin/cc and the compiler options shown below. You can also use

the compiler options found in the makeﬁle /stand/build/config.mk or

/stand/build/config.mod.

To compile your module source code, follow these steps:

1. Change directories to the directory containing the module’s

component ﬁles.

2. For a 64-bit PA target machine, execute the following cc (1) command:

/opt/ansic/bin/cc -I. -I/usr/conf -I/usr/conf/sys \

-Wp,-H300000 +Hx0 +R500 +ESsfc +ESssf +XixdU \

+ES1.Xindirect_calls +ESlit +O2 +Oentrysched +Ofastaccess \