Linux如何记住它的内核堆栈指针？

I know that there are two types of stack in Linux : user stack for each user threads and Kernel Stack for kernel threads (but 1 process). The interruptions, more precisely, the interruption procedures, are the bridges between this two modes, kernel (0) and user (3). The interrupt vector table let the processor loads the right instruction address in the PC register, but how is the stack pointer register changed when it switches in kernel mode? Does the subroutines indicate where's the kernel stack just before its first instruction? Or does the processor uses two stack pointer registers (I really doubt it)?I know that there are two types of stack in Lin