Re: kexec: Clearing registers just before jumping into purgatory

Matthew Garrett
2013-10-11T16:44:46Z

On Fri, Oct 11, 2013 at 06:42:36PM +0200, Richard Weinberger wrote:
> On Fri, Oct 11, 2013 at 6:39 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> > On Fri, Oct 11, 2013 at 06:33:23PM +0200, Richard Weinberger wrote:
> >> On Fri, Oct 11, 2013 at 5:48 PM, Matthew Garrett <mjg59@srcf.ucam.org> wrote:
> >> > On Fri, Oct 11, 2013 at 11:44:50AM -0400, Vivek Goyal wrote:
> >> >
> >> >> Just Curious. How is it useful. IOW, what's your use case of booting a new
> >> >> kernel and then jumping back.
> >> >
> >> > I'm kexecing into a kernel with a modified /dev/mem, modifying the
> >> > original kernel and then jumping back into it.
> >>
> >> How do you update the original kernel?
> >
> > It's still in RAM, so the same way you'd modify any other arbitrary
> > physical address?
>
> So, you have a tool like ksplice which patches the kernel in RAM?

I have /dev/mem and a list of addresses I want to modify.

--
Matthew Garrett | mjg59@srcf.ucam.org