kexec: Clearing registers just before jumping into purgatory

[Vivek Goyal]

On Fri, Oct 11, 2013 at 04:37:27PM +0100, Matthew Garrett wrote:
> On Fri, Oct 11, 2013 at 08:52:06AM -0400, Vivek Goyal wrote:
> > On Fri, Oct 11, 2013 at 01:04:55PM +0200, Daniel Kiper wrote:
> > 
> > [..]
> > > > In theory you can swap between to kernels with the preserve_context
> > > > case.  Technically I like the ability but I don't know that it has ever
> > > > achieved much uptake.
> > > 
> > > I think that this is nice idea too. However, I have not seen its usage in real.
> > > Even once there was an idea to remove that stuff from Linux Kernel.
> > 
> > I have not seen anybody using it. I don't even know if it works or not.
> 
> It works. I'm using it.

Hi Matthew,

Just Curious. How is it useful. IOW, what's your use case of booting a new
kernel and then jumping back.

Thanks
Vivek