Re: [git-pull -tip] x86: msr architecture debug code

Andreas Herrmann
2009-03-05T18:23:53Z

On Thu, Mar 05, 2009 at 09:17:37PM +0530, Jaswinder Singh Rajput wrote:
>
> On Thu, 2009-03-05 at 15:37 +0100, Andreas Herrmann wrote:
> > On Thu, Mar 05, 2009 at 07:42:26PM +0530, Jaswinder Singh Rajput wrote:
> > > On Thu, 2009-03-05 at 14:54 +0100, Andreas Herrmann wrote:
> > >
> > > > All nice suggestions but why in-kernel?
> > > >
> > >
> > > In Kernel Space:
> > >
> > > We can read/write MSRs and can change the bits and see it effect without
> > > writing any code.
> >
> > Sorry, I can't (or maybe I don't like to) follow.
> >
> > (BTW, you don't even need to write C-code. You can use a one-liner in perl
> > or python to seek and read any MSR using /dev/cpu/*/msr.)
> >
>
> You are running these commands on shell when every thing is working.
>
> What you will do if you are not getting the shell and kernel is dumping
> or rebooting before that.

In this case a deep debugfs tree with all the MSR details is not of
use either.

Andreas

--
Operating | Advanced Micro Devices GmbH
System | Karl-Hammerschmidt-Str. 34, 85609 Dornach b. München, Germany
Research | Geschäftsführer: Jochen Polster, Thomas M. McCoy, Giuliano Meroni
Center | Sitz: Dornach, Gemeinde Aschheim, Landkreis München
(OSRC) | Registergericht München, HRB Nr. 43632