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From: venkatram867@gmail.com (Ram Tummala)
To: kernelnewbies@lists.kernelnewbies.org
Subject: How can I change cr0 register in redhat system
Date: Mon, 23 Jul 2012 09:49:35 +0530	[thread overview]
Message-ID: <-6574249348144482851@unknownmsgid> (raw)
In-Reply-To: <CAPihQtsduGcSV16ood+nHXBZEcYXNBx45pX9s87mLekXt_vQuA@mail.gmail.com>

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
>
> _______________________________________________
> Kernelnewbies mailing list
> Kernelnewbies at kernelnewbies.org
> http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies

  reply	other threads:[~2012-07-23  4:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-07-23  4:00 How can I change cr0 register in redhat system Fan Yang
2012-07-23  4:19 ` Ram Tummala [this message]
2012-07-23  8:37   ` siddharth saxena
2012-07-23 11:40     ` Jonathan Neuschäfer
     [not found] ` <219833562776487968@unknownmsgid>
2012-07-23 13:38   ` Fan Yang
2012-07-23 14:01     ` Jonathan Neuschäfer
2012-07-23 17:38     ` Ram Tummala
2012-07-24  2:05 ` Peter Teoh

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