On Thu, Oct 6, 2011 at 11:28 AM, Mulyadi Santosa <mulyadi.santosa@gmail.com>wrote:
Hi...
On Thu, Oct 6, 2011 at 02:34, Vaibhav Jain <vjoss197@gmail.com> wrote:
Hi,
I am trying to run a program that scans memory from a given physical address using /dev/mem. It uses mmap to map physical address from /dev/mem. So to start with I used /proc/iomem to look up the physical memory mapping and found the address 00010000 to be the starting address for System ram. But whenever I provide this address to the program it throws an error of "Operation not permitted".
Probably this could also due to mmap NULL dereferencing protection (at least that's how I name it :) )
By default, the lowest 65536 byte (10000 in hex) is protected from mapping etc. It practically render such null dererefencing useless.
-- regards,
Mulyadi Santosa Freelance Linux trainer and consultant
blog: the-hydra.blogspot.com training: mulyaditraining.blogspot.com
Hi, I tried the same with other addresses (greater than 0x10000 ) also but it is throwing the same error. Is there a way to get over this ? Thanks Vaibhav Jain