Internal Kernel Debugger

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An Internal Kernel Debugger allows you to view data inside core structures of the system, like memory, tasking, and other structures. It is very helpful for debugging purposes when a tool such as GDB is not available.

Introduction

The concept of an internal debugger involves triggering a mini-shell within the operating system. This process generally requires a keyboard driver (or another form of input). The shell provides several commands for dumping registers, reading system structures, and other debugging tasks. One of the challenges in implementing this type of debugger is maintaining the system's operational integrity while enabling access to its internal components.

Ways to implement

The implementation of an internal kernel debugger varies by operating system. Following the concept outlined above, one approach is to allow the user to trigger the debugger by pressing a key (e.g., the letter Q). When activated, the kernel could halt, displaying a register dump, and resume when Q is pressed again. Alternatively, a more advanced setup could load a more complex debugger, providing full control similar to an initramfs shell on Linux. For a simpler OS, the debugger can offer a basic shell able to inspect system information, such as structures like the GDT and IDT. This would serve as a lightweight, integrated debugger, similar to GDB but likely less complex but less difficult to control and use.