On Mon, 12 Nov 2018 02:00:02 +0800, Carter Cheng said:
> Thanks for the reply but the link doesn't quite answer the question. I am
> wondering how the pointer is handled so that there is one per thread by the
> compiler. I perhaps was under the perhaps mistaken impression that the
> stack pointer frame pointer management inside the compiler makes certain
> assumptions in user space- but i am unsure how this applies to kernel space.

For regular function calls, a kernel stack works exactly the same as a function
stack in userspace (remember, it's the same compiler, and other tools like the
linker and gdb need to be able to understand function calls).

Where things are different are what happens if an interrupt or a call to
schedule() or enter/exit the kernel (or a few other similar situations I can't
remember at 2AM) causes a different thread to start running - for those cases,
there's architecture-dependent shim code (usually involving at least a bit of
assembler) to do the register swapping needed.