Using a statically compiled C file as rootfs

Question

I want to boot my imx53-qsb board using not a normal rootfs but a statically compiled hello_world.c file in other words a hello_world_static.out. To achieve that, I wrote a hello_world.c file cross compiled it statically and I put it in my mmcblk0p1 ext4 partition of my sd card. I put my uImage and my u-boot.imx in the mmcblk0. After booting my system I got a kernel panic :

Kernel panic - not syncing: No init found. Try passing init= option to kernel. See Linux Documentation/init.txt for guidance.

Any solution ? Thanks

Answer 1

You should provide init= param to kernel cmdline (from u-boot). For example, if your binary file name is init and you have put it to /sbin directory (on your rootfs partition), you should add init=/sbin/init to your kernel cmdline in u-boot (in bootargs variable).

For example you can do next (in u-boot shell, before running bootm or booti command):

setenv bootargs root=/dev/mmcblk0p1 rw rootfstype=ext4 init=/sbin/init

Also, check if you really have your rootfs on mmcblk0p1. Usually mmcblk0p1 is FAT32 partition which contains bootloader files and images to copy to RAM. Rootfs is usually located on mmcblk0p2 (and formatted as ext4).

For details see:

[1] Documentation/kernel-parameters.txt (look for init= param)

[2] u-boot README file (look for Boot Linux: line)

[3] Documentation/init.txt