Stack Overflow
Stack Overflow

Questions tagged [supervisor-mode]

7 questions
7
votes
2 answers

ARM. Access user R13 and R14 from Supervisor mode

How do I access the user R13 and R14 which are saved when supervisor mode is entered? I am using an ARM7TDMI. I.E. I do not want to access supervisor R14 which now contains the return address to user mode, instead want the value of user mode's link…
Tarski
  • 5,360
  • 4
  • 38
  • 47
6
votes
1 answer

What is the instruction tlbiel and what does it do?

I've recently come across an instruction called tlbiel and I'm curious as to what it means and what purpose it serves. After doing some intense Google searching, I saw one IBM document that lead me to believe it's hypervisor-related. The current…
user6501446
3
votes
2 answers

User mode vs supervisor mode

I have a few questions on the user-mode and supervisor-mode on Unix-like machines. What is the difference between user-mode and supervisor-mode? I know that the user processes cannot access all memory and hardware and execute all instructions. Is…
user58860
  • 31
  • 1
  • 2
3
votes
2 answers

How does Windows switch to supervisor mode during a system call?

How does Windows switch to supervisor mode during a system call? I heard something about a "trap 0", but that doesn't even seem like an x86 instruction. I stepped through some system calls, but I can't find any. Do a lot of Windows system calls run…
Jens Björnhager
  • 5,632
  • 3
  • 27
  • 47
2
votes
2 answers

What is the difference between Operating system processing modes and CPU processing modes?

A process has two modes: User mode and supervisor mode. Also CPU has different privilege levels to run. Are these two concepts the same? In Linux Kernel Projects By Gary Nutt, it is mentioned that to make a system call, a process must first acquire…
pflz
  • 1,891
  • 4
  • 26
  • 32
1
vote
1 answer

Questions about supervisor mode

Reading OS from multiple resources has left be confused about supervisor mode. For example, on Wikipedia: In kernel mode, the CPU may perform any operation allowed by its architecture .................. In the other CPU modes, certain restrictions…
NickFury
  • 41
  • 3
1
vote
1 answer

Already executing in supervisor mode; how to start user mode? (several scenarios)

I've been doing some extra homework from my textbook to prepare for my 68000 Assembly exam coming up in the next few weeks. There are currently 4 questions which ask how the user mode can be started while already being executed in supervisor mode. I…
Plaidypus
  • 81
  • 9