Could you explain what processor modes are?

The processor operation modes are different privilege levels and contexts in which the processor can execute instructions. Typically, two main modes are distinguished:

• User mode — a restricted mode in which application programs operate. Access to critical resources and commands is limited in this mode to protect the system.
• Kernel mode — a privileged mode in which the operating system and drivers operate. Here, the processor has full access to hardware and system resources.

Switching between modes occurs during system calls, interrupts, or exceptions, ensuring the security and stability of the system.