Kernel memory mapped into user process

[Shashi Kiran T.R.]

Hi ,

    I have a proposition at hand to optimize getting system time by
avoiding
the system call(gettimeofday()) overhead. This can be implemented by
keeping a read-only page of kernel memory mapped into user processes
for reading quickly. A kernel process can keep that page up-to-date.

   I did some browsing of this mailing list archives to get the
following related
topics:
*  mapping user space buffer to kernel address space
* Direct I/O
* Zero Copy IO
  None of these seem to specifically address my problem.

So can the experienced please throw some light on the issues involved
in having a read-only page of kernel memory mapped into user process.
Any help/suggestions will be much appreciated. Please CC your comments
to "[e-mail]"

Thanks and Regards,
  Shashi