privilege levels and kernel mode

[ranjith kumar]

Hi,
    I am using pentium-4 processor. My operating
system  is Linux version 2.4.22-1.2199.nptl

  I want to measure performance events like number of
memory reads, number of cache misses occured while
running  a "C" program. For that I have to wright some
values into "Model specific registers of pentium-4
processor". But those registers can be written ONLY at
privilege level of zero of pentium4 processor.

 We know that application programs we write (for
example any C program)are run at privilege
level-3(user mode).

I know how to include assembly instructions in a C
program to wtrite into "Model specific registers". But
that program has to be run at privilege level zero.

How to run a C program at privilege level zero??
Can any one help me?

Thanks in advance.

 

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