Sign Up to our social questions and Answers Engine to ask questions, answer people’s questions, and connect with other people.
Login to our social questions & Answers Engine to ask questions answer people’s questions & connect with other people.
Lost your password? Please enter your email address. You will receive a link and will create a new password via email.
Please briefly explain why you feel this question should be reported.
Please briefly explain why you feel this answer should be reported.
Please briefly explain why you feel this user should be reported.
I’m designing a memory chip, and since this seems like the best place to ask a related system software question…
On a modern x86 processor, does system-level code (protection ring 0) run on physical memory addresses?
And is it the same for the 64 bit spec?
(I need to know so I know whether addresses for system code go through the virtual/segmented memory subsystem or not.)
They run as any other code. The only difference between Ring 0 the other rings is that Ring 0 can execute privileged instructions, and thus modify the memory address space and structure. This privilege, however, does not mean that Ring 0 cannot use virtual memory just like any other code. It is technically possible to run all processes in Ring 0 and maintain the same virtual memory behavior, assuming the processes don’t attempt to modify it. It is also possible to run less privileged ring processes without virtual memory address spaces.