Geek Answers Handbook

What does the User / Supervisor bit mean in the page table entry?

I try to understand:

  • The User / Supervisor bit is used to distinguish between kernel memory pages and what comes from the user process.
  • user / supervisor bit changes when execution moves to the kernel when making a system call
  • Or perhaps none of them.

Can someone clarify?

+5
source share
1 answer

In the Intel virtual memory system, the user / supervisor bit set to 1 for a specific page means that "this page is available for a process running in user mode (as opposed to supervisor mode)," see here .
In what mode the process is executed, the supervisor bit in the CPU status register is determined. 1 bit supervisor means execution in supervisor mode, see here . The supervisor bit in the status register changes when execution moves to the kernel.
So both of your assumptions are true, but they relate to two different bits.

+2
source

More articles:


All Articles