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Linux Kernel Source Update

Linux Kernel Source Update

1. Clone the kernel source from BBB official GitHub repository (https://github.com/beagleboard/linux) $\to$$\to$ This will clone the master branch of the repository. You will need to checkout a specific branch (i.e., kernel source version).

   • 4.14 is used for this project

     In the workspace/source/ directory:

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     git clone https://github.com/beagleboard/linux.git linux_bbb_4.14
     

   • cd to linux_bbb_4.14/ and run git checkout 4.14.

2. Compile and generate the kernel image from the downloaded kernel image directory (workspace/source/linux_bbb_4.14/)

   • Step 1:

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     make ARCH=arm distclean
     

     Removes all the temporary folder, object files, images generated during the previous build.

     Also, deletes the .config file if created previously.

   • Step 2:

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     make ARCH=arm bb.org_defconfig
     

     Creates a .config file by using default config file given by the vendor (Default config file can be found in workspace/source/linux_bbb_4.14/arch/arm/configs/)

   • Step 3 (Optional):

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     make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- menuconfig
     

     Run this command only if you want to change some kernel settings before compilation.

   • Step 4: Compile kernel source

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     make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- uImage dtbs LOADADDR=0x80008000 -j4
     

     Creates a kernel image uImage.

     Compiles all device tree source files, and generates dtbs.

     #error New address family defined, please update secclass_map. can be resolved by:

     1. scripts/selinux/genheaders/genheaders.c $\to$$\to$ comment out #include <sys/socket/h>

     2. scrpts/selinux/mdp/mdp.c $\to$$\to$ comment out #include <sys/socket.h>

     3. security/selinux/include/classmap.h $\to$$\to$ add #include <linux/socket.h>

     fatal error: mpc.h: No such file or directory error may arise, which is caused by the lack of multiple precision complex floating-point library development package libmpc-dev. Resolve this error by running:

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     sudo apt install libmpc-dev 
     

   • Step 5: Build kernel modules

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     make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- modules -j4
     

     Builds and generates in-tree loadable(M) kernel module (.ko).

   • Step 6:

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     sudo make ARCH=arm modules_install
     

     Installs all the generated .ko files in the default path of the computer (/lib/modules/<kernel_ver>).

     Now, you should be able to see /lib/modules/4.14.108+/ directory.

3. Update the $\mathrm{\mu }$$\micro$SD with the new kernel image, dtb and kernel modules

   • To update the kernel image and dtb in the $\mathrm{\mu }$$\micro$SD:

     • Copy workspace/source/linnux_bbb_5.10/arch/arm/boot/uImage to /mdeia/klee/BOOT/ ($\mathrm{\mu }$$\micro$SD card).

     • Copy workspace/source/linnux_bbb_5.10/arch/arm/boot/dts/am335x-boneblack.dtb to /mdeia/klee/BOOT/ ($\mathrm{\mu }$$\micro$SD card).

       Don't forget update dtb! It will hang the boot process at 'Starting kernel ...'.

       Select the dtb file whose name matches the one that is present in the BOOT partition of the $\mathrm{\mu }$$\micro$SD card.

   • To update the kernel modules in the $\mathrm{\mu }$$\micro$SD:

     • Copy newly installed kernel modules /lib/modules/4.14.108+/ to /media/klee/ROOTFS/lib/modules/ ($\mathrm{\mu }$$\micro$SD card).

     Run sync to flush left-over contents in the buffer to the media

4. Boot the board from the updated $\mathrm{\mu }$$\micro$SD card.

5. Check the kernel version after login:

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   uname -r
   

   It should display the updated kernel version. (4.14.108+ in my case)