why systemCall need a interrupt rather than directly call kernel code . i think in protected mode ,the user's process can not get the kernel address ,so need interrupt to come to the kernel address ,is it true?
why systemCall need a interrupt rather than directly call kernel code . i think in protected mode ,the user's process can not get the kernel address ,so need interrupt to come to the kernel address ,is it true?
It's not an interrupt. It is an EXCEPTION. An exception is required to change the processor mode.