Answer Posted / softy

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

Explain process management system calls in linux?

559

What are system calls used for process management in linux?

587

what are different ways the context switch happens from user to kernel space or vice-versa ?

2144

I would like to know whether Simado and Setu products are they EPBX or not ?

1933