What can be the causes for the processor to transmission from user mode to kernel mode? Can the user execute arbitrary code after transitioning?
1) There are several reasons for transmission of the processor from user mode to kernel mode. Some of them are as follows:
a) There are several system calls (also known as privileged instructions) such as file read, write, delete etc which needs the processor to be in kernel mode for execution.
b) For security purposes such that user programs don't crash the operating system.
c) CPU scheduling and all other functions of CPU happens in kernel mode.
No, the user can't execute the arbitrary code in the kernel mode. For the execution, the processor again has to make the transition from kernel mode to user mode.
Hope that helps :)
What can be the causes for the processor to transmission from user mode to kernel mode?...
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