System Calls Interview Question:

What are the different ways the Linux can switch from User Space to Kernel Space & vice-versa?

Submitted by: Administrator

There are 2 situations when Linux can switch from user Space
to Kernel Space:-

1) by doing System calls
2) When interrupt comes (to handle interrupt)
3) by executing 128 (0x80 ) instruction or doing sysenter

Linux can switch from kernel Space to User space:-
1) process in kernel mode is preempted.
2) After completion of Interrupt handler / System call
3) performing sysexit sys call
Submitted by: Administrator