From mboxrd@z Thu Jan  1 00:00:00 1970
From: venkatram867@gmail.com (Ram Tummala)
Date: Mon, 23 Jul 2012 09:49:35 +0530
Subject: How can I change cr0 register in redhat system
In-Reply-To: <CAPihQtsduGcSV16ood+nHXBZEcYXNBx45pX9s87mLekXt_vQuA@mail.gmail.com>
References: <CAPihQtsduGcSV16ood+nHXBZEcYXNBx45pX9s87mLekXt_vQuA@mail.gmail.com>
Message-ID: <-6574249348144482851@unknownmsgid>
To: kernelnewbies@lists.kernelnewbies.org
List-Id: kernelnewbies.lists.kernelnewbies.org

On Jul 23, 2012, at 9:32 AM, Fan Yang <lljyangfan@gmail.com> wrote:

> hi all:
>        when I change the cr0 register I get a "Segmentation fault (core dumped)".
>        my code is :
>
>
> .data
> .text
> .global _start
> _start:
>         movl %eax, %cr0
>
>       this code can work well in ubuntu system when I use root to run it. So what can I do to work it in redhat system?
Changing a control register is a privileged operation. You can't do it
from the user space. You can only do it from ring 0.

Venkatram Tummala
>
>      thanks
>
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