FROM:LDD Chapter 2

Quick Reference
insmod
modprobe
rmmod
  User-space utilities
that load modules into the running kernels and remove them.
#include
<linux/init.h>
module_init(init_function);
module_exit(cleanup_function);
 
Macros that designate a module’s initialization and cleanup
functions.
__init
__initdata
__exit
__exitdata
  Markers for
functions (__init and __exit) and data (__initdata and __exitdata) that are only
used at module initialization or cleanup time. Items marked for initialization
may be discarded once initialization completes; the exit items may be discarded
if module unloading has not been configured into the kernel. These markers work
by causing the relevant objects to be placed in a special ELF section in the
executable file.
#include <linux/sched.h>
  One of the most
important header files. This file contains definitions of much of the kernel API
used by the driver, including functions for sleeping and numerous variable
declarations.
struct task_struct *current;
  The current
process.
current->pid
current->comm
  The process ID and
command name for the current process.
sys/module
/proc/modules
 
/sys/module is a sysfs directory hierarchy containing information on
currently-loaded modules. /proc/modules is the older, single-file version of
that information. Entries contain the module name, the amount of memory each
module occupies, and the usage count. Extra strings are appended to each line to
specify flags that are currently active for the module.
vermagic.o
 
An object file from the kernel source directory that describes the environment a
module was built for.
#include <linux/module.h>
  Required
header. It must be included by a module source.
#include
<linux/version.h>
  A header file containing information on the
version of the kernel being built.
LINUX_VERSION_CODE
  Integer
macro, useful to #ifdef version dependencies.
EXPORT_SYMBOL
(symbol);
EXPORT_SYMBOL_GPL (symbol);
  Macro used to export a symbol
to the kernel. The second form exports without using versioning information, and
the third limits the export to GPL-licensed
modules.
MODULE_AUTHOR(author);
MODULE_DESCRIPTION(description);
MODULE_VERSION(version_string);
MODULE_DEVICE_TABLE(table_info);
MODULE_ALIAS(alternate_name);
 
Place documentation on the module in the object
file.
module_init(init_function);
module_exit(exit_function);
 
Macros that declare a module’s initialization and cleanup functions.
#include
<linux/moduleparam.h>
module_param(variable, type, perm);
 
Macro that creates a module parameter that can be adjusted by the user when the
module is loaded (or at boot time for built-in code). The type can be one of
bool, charp, int, invbool, long, short, ushort, uint, ulong, or
intarray.
#include <linux/kernel.h>
int printk(const char * fmt,
...);
  The analogue of printf for kernel code.