Compiling Kernel Source

Exercise 2

As the kernel source is modified to add a new system call in Exercise1, then we need to compile it to generate a new kernel image and this new image is used at the next boot of the system.

(Mainline kernel is called as vanilla kernel)

Note: I am assuming that you are in source directory, at /usr/lib/linux-2.6.32

Step1: Assign kernel version tag.

 

To do so open the Makefile at the path /usr/lib/linux-2.6.32/Makefile and at the top of the file you will find the field EXTRAVERSION, edit as follows

$ Vim Makefile

Modify: EXTRAVERSION = mytest

*save the above changes to file.

Step2: Choose kernel configuration.

 

To do so type that following command. This will generate a configuration file “.config”. Any file that starts with “.” is a hidden file, to list the hidden files use option 'a' with 'ls' command.

$ make menuconfig (this pumps kernel info onto console, wait until prompt returns)

Note: refer to man pages on make, type “make help” at your terminal.

Step3: Compile the source to create kernel image (raw) and modules.

$ make

This takes around 30 min on a normal desktop, to speed up, create threads if yours is a multicore machine. To do so type the following command, here 4 is the no of threads.

$ make -j4

Step4: Install the modules on file system

 

To do so type the following command.

$ make modules_install

This copies the modules into disk space and adds folder at /lib/modules/[name]

Step5: Update bootloader and boot folder with new kernel information.

To do so type the following command.

$ make install

Grub contains the list of kernel images, one among them is chosen at boot time.

Oops...! if any problem with above procedure, check out this link, usually i follow this procedure.

Click here for Exercise3

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