which of the following instr. is needed if we want to convert from Kernel mode to User mode in OS?

Question

option a) Previlized instr. with interrupt

Option b) Non previlized instr

option c) Previlized instr. without interrupt

Answer 1

Kernal to used mode is non privilized but from user to kernal is privilized mode.

http://cs.stackexchange.com/questions/11230/changing-from-kernel-mode-to-user-mode-and-vice-versa

Comments

Bro Actually mode changing control is in Kernel control. so definitly a privilized instr. is needed .

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need to read that 

http://cs.stackexchange.com/questions/11230/changing-from-kernel-mode-to-user-mode-and-vice-versa

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I think Privilized Instr. without S/W interrupt is needed as we are already in kernel mode.