Http://hi.baidu.com/ah%5F%5Ffu/blog/item/57b76201e27095de267fb5d4.html Finally, I made up my mind to study the Linux kernel and drive development. I was not afraid of the shame of tens of millions of people. I was brave enough to write my learning process: 1. About Directories
/Lib/modules/2.6.9-42. elsmp/build/the directory where the kernel source code is located
Generally, run the following command to enter the Directory: CD/lib/modules/$ (uname-R)/build/
This directory actually points to:/usr/src/kernels/2.6.9-42. EL-smp-i686 2. Compile the makefile used by the driver.
In fact, when compiling the driver, a preset makefile is used, which is located:
/Lib/modules/$ (uname-R)/build/makefile
Note: m is capitalized. 3. source code of the Linux driver Hello World copied online:
// Hello. c
# Include <Linux/init. h>
# Include <Linux/module. h> Module_license ("dual BSD/GPL "); Static int hello_init (void)
{
Printk (kern_alert "Hello world! \ N ");
Return 0;
} Static void hello_exit (void)
{
Printk (kern_alert "goodbye! \ N ");
} Module_init (hello_init );
Module_exit (hello_exit ); 4. Write a makefile to compile the driver: (version 1 is the simplest)
# The following line shows the content of the makefile. Note that M is capitalized.
OBJ-M: = Hello. o Save hello. C and makefile in the same directory, and then execute:
Make-C/lib/modules/'uname-R'/build subdirs = $ PWD modules
In this way, the driver is compiled, and the result is the hello. Ko file.
Note: makefile must be written as makefile. If it is written as makefile, it cannot be compiled. (It takes more than n time to complete this step) 5. Write another makefile: (version 2: the most time-consuming)
# The content of makefile is as follows:
OBJ-M: = Hello. o
Kernel_dir: =/lib/modules/$ (shell uname-R)/build
PWD: = $ (shell PWD)
ALL:
Make-C $ (kernel_dir) subdirs = $ (PWD) Modules
Clean:
RM *. O *. Ko Then execute: make the compilation is successful, and the command line does not add parameters, which is very easy.
Note: All: And clean: The following row. The front is a tab key. 6. Load the driver:
Run
Insmod./Hello. Ko
The screen does not respond. (Because I used a remote terminal to connect to Windows)
OK. Let's let the time go back and go back to loading the driver. open another window and execute:
Tail-F/var/log/message
Then execute the following in the original window:
Insmod./Hello. Ko
Haha, the long-awaited Hello world is displayed in the/var/log/message file! 7. view the driver:
Lsmod saw the hello driver in it. 8. Uninstall the driver:
Rmmod hello
Goodbye is displayed in/var/log/message. |
