Kernel Debugging Using Eclipse IDE

Setup Guide for Kernel Debugging Using Eclipse IDE
Done By: Koustubha D and Rishabh S

Arizona State University.

A)Software Setup:

1. Eclipse IDE Setup:

• In Fedora, Go to Application-> Add Remove Software Menu. OR In some latest versions of Fedora, the same option could be found out in System¬>Administration->Add Remove Software menu.
• Now in the Browse tab, select the Development from the left side panel and check the
• Eclipse in the right side list.
• Apply the settings.
• Eclipse along with its dependencies will be installed.

2. CDT setup in Eclipse:

• Now open the Eclipse IDE by selecting Application->Programming->Eclipse menu.
• First time, it might ask you to select/create a workspace. Do the needful.
• Now in the menu bar, select Help-> Software Update->Find and install.
• Now select the “Search for new features to install” radio button and click next.
• Now in the install screen, select New Remote Site.
• Give Name – CDT and URL =http://download.eclipse.org/tools/cdt/releases/callisto
• See the screenshot below:
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3. Qemu Setup:

• Open a terminal
• su -
• eneter password
• yum install qemu
• type y after qemu installation in terminal type qemu to check installtion after that install kqemu.
• Download Kqemu kqemu-1.3.0pre11.tar.gz [same version that of qemu] either from the website: http://www.nongnu.org/qemu/download.html
• Now go to the Kquemu directory.
• Run following commands in sequence:
• ./configure
• make
• make install
• To make sure that kqemu is setup properly give the command “/sbin/modprobe kqemu”.
• If it doesn't give any output, your kqemu is installed properly.

B)Kernel Setup and Configuration:

1. Kernel Setup:

• Get the latest kernel source code version 2.6.30 from the CVS repository or from the URL http://www.kernel.org
• Unzip and untar the source code in your local directory. Give the following command: tar xvf linux-2.6.30.tar
• Now create an output directory:
• mkdir -p /mnt/build/linux-2.6

2. Setting up the Kernel Configuration

• Now change to your Kernel Source code directory where you have extracted it. For example, if you have downloaded it at /home/user/Desktop directory, then give the following command:
• cd /home/user/Desktop/linux-2.6.30
• Next, we'll configure the kernel. Issue the following command:
• create a directory as following
• su -
• mkdir -p /mnt/build/linux-2.6
• make oldconfig O=/mnt/build/linux-2.6
• Just keep pressing enter to use the default answers to all the questions that the kernel configuration program will ask you.
• Next , we enable the debugging options in the kernel configuration:
• make menuconfig O=/mnt/build/linux-2.6
• Now in the “Kernel Hacking” menu, enable both “Compile the kernel with debug info” and “Compile the kernel with frame pointers.”. After that issue the following command.
• make mrproper

C)Eclipse Kernel Project Setup:

• Now open the eclipse IDE.
• Start a new project, by using File->New->Project. Then select "C Project", "Makefile project", "Empty Project". (You might get this option as Standard Make C Project.)
• Now enter a project name and specify a specific directory for the project sourcecode. To do this, first uncheck the "Use default location" checkbox.
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• Click finish.
• If you hadn't disabled indexing, Eclipse will now start indexing the Linux kernel sourcecode. This might take a long time.

• Once Eclipse finishes indexing the kernel sourcecode. We are ready to configure our debugger. Right-click on the project-name in the left pane (Project explorer) and select "Properties".
• Select the “C C++ Make Project” from the panel on the left side of the screen.
• Now Uncheck "Use default build command" and enter make O=/mnt/build/linux-2.6
• Modify the build location by clicking the "File system..." button and browsing to /mnt/build/linux-2.6

Now you are ready to build your project. Through the menu-bar select "Project->Build all" or press "Ctrl-b".

The building might take a lot of time. Once it is done, start the Qemu by giving the following command on console: [/dev/sda1 is your primary boot drive you can also try with /dev/zero]

qemu -s -S -hda /dev/sda1 -kernel /mnt/build/linux-2.6/arch/x86/boot/bzImage

Instead of /dev/sdb1 above, you need to choose the disk partition where your /boot resides. Give df command to check where your /boot resides.

Because the CPU is "frozen" at startup, the Qemu window won't show anything useful yet.

Now come back to the Eclipse IDE.

Through the menubar, select "Run->Debug Configurations" or Debug. Double-click "C/C++ Local Application". Modify the "C/C++ Application" text entry to point to the actual Linux kernel, being /mnt/build/linux-2.6/vmlinux

Click on the "Debugger" tab, and in the "Debugger" listbox select the "gdbserver Debugger". Next, modify the "Stop on startup at:" to "start_kernel".

• Below this, you'll notice a frame named "Debugger Options"; click the "Connection" tab in this frame and modify the "Type" to "TCP" and the "Port number" to 1234. Continue by clicking the "Debug" button.
• Eclipse might compile and link a bit, but will finally launch the debugger and ask if you want to switch to the debugging perspective. Say yes.
• The next screenshot shows the debugging perspective. Just like with normal applications, you'll see that the line it is about the execute is highlighted.
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• Now switch to the Qemu screen. You will see the following:
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• In your Eclipse, the control will be in start_kernel function. By using "Run->Step over" or pressing the "F6" key, you can execute the kernel code line by line and examine what's happening.
• If you want to see the assembly instructions which are being executed, you can add a view which displays this by selecting "Windows->Show View->Disassembly".
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You can add breakpoints, inspect variables, inspect memory and much more.The whole Kernel Code is yours now. Enjoy Debugging.