Questions on linux kernel
 

Hi all

i have few question relating to linux kernel memory here are the questions

1) Can Kernel space access user space memory yes or no ?
if no what happens when kernel space tries to access user space memory

2) Can Device memory(character device/chipset on the hardware board) be
mapped to user space ?

Cheers
NRK

Hi -

Here are a couple of good links:
http://tldp.org/LDP/tlk/mm/memory.html

http://people.ee.ethz.ch/~arkeller/l...ace_howto.html

I understand that Robert Love has come out with a new edition of his (Most Excellent!) book on Linux kernel internals, which you might be interested in:

http://www.amazon.com/Linux-Kernel-D...dp/0672329468/

'Hope that helps .. PSM

Thank you paul

1) I wanted to know can kernel space access user space pointer yes or no ?
if no then what happen when kernel tries to access user space pointer.

2) so you say in kernel if i need some memory from user space
then this function kmalloc(1024,GFP_USER); would work fine yes or no ?

Read the following manual carefully.
Kmalloc allocates only in kernel-space.
http://www.fiveanddime.net/man-pages/kmalloc.9.html

Moreover I didn't understand why would anyone want to allocate user space memory from kernel space ? In what kind of cases is this required ?

Thanks anisha

it was of great help from your end
that link you sent me clearly explains the Allocating and freeing dynamic kernel memory.


Nakul

You are most welcome :hattip: