read physical address space

From: alan hopes
Date: Tue Nov 17 2015 - 10:21:54 EST


I am new to kernel and working on a college project.

I have kernel module which takes process ID. Based on the PID, I walk
its page tables and get to PTE for a particular VMA area.

I convert PTE to physical address (phy_addr) and now I want to read
from the that physical address.

I have made sure the page containing the physical address is mapped
but if I do printk (*phys_addr) , then kernel crashes.

I think I am missing some important concept here. Do I need another
driver to access physical space, may be a PCI driver as RAM being a
PCI device ?

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