From linux version 2.26.* onwards there is a filter provided by the default kernel configuration disabling the users from accessing the ram area. There was a lengthy discussion on the same topic in this mailing list 2 years back-
http://www.spinics.net/lists/newbies/msg41020.html

If you still want to access the RAM you disable this option in the kernel configuration menu. kernel hacking -> Filter access to /dev/mem.

Disclaimer: You will be responsible for the integrity of the RAM contents :)

On Fri, Apr 19, 2013 at 12:11 PM, er krishna <erkrishna@gmail.com> wrote:

Root user and trying to acess physical ram reason. I wanted to know is there any limit for mmap through use space and how to override them.

Krish

On Fri, Apr 19, 2013 at 12:09 PM, Prabhu nath <gprabhunath@gmail.com> wrote:

Is this address (0xB202E7000) a memory address or device address ?. R you working as privileged user or a normal user. ?

On Fri, Apr 19, 2013 at 11:50 AM, er krishna <erkrishna@gmail.com> wrote:

Hi All,

I am trying to do mmap from user space program to fetch physical memory base address B202E7000 and size F0. But I am getting operation not permitted error. Any suggestion by which I can increase the privilage by sysctl to acess this reason ?

Krishna

--
Regards,
Prabhunath G
Linux Trainer
Bangalore

--
Regards,
Prabhunath G
Linux Trainer
Bangalore