Linux kernel source tree build load Hello module

Before loading the module, the book said to first establish the kernel source tree, then, how to establish the kernel source tree?

First, you need to know the kernel version of your OS and use Uname-r to find

　　

The corresponding version directory can be seen under the/url/src/directory

　　

If no kernel can be obtained with Apt-cache search Linux-source

　　

Download the kernel with sudo apt-get install linux-source-3.13.0

After the download is complete, a corresponding compressed file is generated in the folder linux-source-3.13.0.tar.bz2

Then unzip the file tar jxvf linux-source-3.13.0.tar.bz2

Enter the extracted directory

Then enter the root permission su (here into the failure prompt authentication failure), enter the following command in the terminal:
sudo passwd
Password: Your current password
Enter New UNIX Password: This is the root password
Retype new UNIX Password: duplicate root password
You will then be prompted for successful information.

Enter the command make oldconfig to start configuring the kernel.

Before checking the data on the Internet to see the configuration kernel will take about one hours, but I input the command output

　　

The data says that after the configuration is complete, a new directory is generated under/lib/modules/lib/modules/3.16.0-30-generic/

　in this directory ls a bit found already exists this directory = =! That is, the original system already exists kernel source tree .

　　

Now that the kernel source tree already exists, all we have to do is load the Hello module into the kernel.

Here is the source code for Hello

　　

1#include <linux/init.h>2#include <linux/module.h>3Module_license ("Dual BSD/GPL"); 4 Static intHello_init (void) 5 { 6PRINTK (Kern_alert"Hello, world\n."); 7     return 0; 8 } 9 Static voidHello_exit (void) Ten {  OnePRINTK (Kern_alert"Goodbye, Cruel world\n");  A }  - Module_init (hello_init); -Module_exit (Hello_exit);

Writing Makefile files to code

1 obj-m: =2 kerneldir: =/lib/modules/3.16. 0-3 PWD: =45     $ (make)-C $ ( Kerneldir) m=67     

Run make

　　

Generate the appropriate Hello.ko file

　　

Then load the Hello.ko module, note to load in root mode, and then Lsmod view the loaded module (the book says Hello World is output in the console, but my console does not output)

　　

Uninstalling the module

　　

Although the console does not output, you can view the output of the Hello module under/var/log/syslog

　　

Linux kernel source tree build load Hello module