Add new kernel boot arguments

[Marko Jurin]

Hello !

I want to add new boot arguments which are passed from grub to kernel. I
know it's possible to set variable GRUB_CMDLINE_LINUX_DEFAULT in grub.cfg
file, but I want to retrieve values for some of the arguments from EEPROM.
So, I suppose I should patch source code, but I haven't found the part that
is dealing with these functionalities. Do you have some useful advice which
could help me?
Thank you