Paging and system calls

["Kasim Sinan Yildirim" <yildirim@bilmuh.ege.edu.tr>]

Hi,

I am working on a small kernel and i am examining the source code of the 
linux.

Since every task has its own page tables, when task switching occurs,  the 
cr3 field of the TSS is put to the cr3 register which is page directory base 
register.

İn my operating system, when a system call occurs, the user level code jumps 
to system level code by changing its selectors to KernelCS and KernelDS. But 
at this point, the cr3 register still points to the page directory of the 
user process. So, the actual code that is pointed by kernel level page 
directory is not equal to the user level page directory entry. As a result , 
the system fails.

How this problem is solved in Linux? Have you got any solution to my problem?

Thanks...