Understanding Thread and Kernel Mode Transition
When we talk about threads in Linux, every process can have one or more of them. In a simple program, there’s usually just one — the main thread. Threads usually run in User Mode, but sometimes the...
Mersad Karimi
HAL and the Abstraction Layer for Register Access
As hardware vendors expose low-level functions to access device registers, we use those functions to port software to a board — for example to run Linux or FreeRTOS. But drivers do not call vendor ...
File Download via TFTP in U-Boot
Summary If your saved environment (and scripts) are unavailable after boot, you can embed a small U-Boot command in C that downloads a file via TFTP and writes it to MMC. Save the C file in cmd/, a...
Resetting Login Password by Changing Kernel Command Line
Summary One easy way to reset a local login password is to set a shell (e.g. Bash) as the system init via the kernel command line. After boot, the kernel will start that shell instead of the normal...
Dynamic Searching for MMC in U-Boot
Summary A common issue is that after hardware changes the MMC device number can change (e.g. mmc0 → mmc1), so U-Boot scripts or operations that rely on a fixed MMC number fail. Instead of changing ...
Writing init program using Python on Linux
As you may know, the first process in Linux is the init (PID 1) — it runs while the system is up. Init is normally a compiled program (statically or dynamically linked). Can we write init in Python...