Re: Preliminary kexec support for Linux/m68k

Simon Horman
2013-09-20T19:19:19Z

On Fri, Sep 20, 2013 at 09:15:02AM +0200, Geert Uytterhoeven wrote:
> Hi Simon,
>
> Thanks for your comments!
>
> On Thu, Sep 19, 2013 at 11:07 PM, Simon Horman <horms@verge.net.au> wrote:
> > Pasting two series in one was a bit confusing for me at first.
> > Perhaps you could consider posting two separate series in future.
>
> Sorry, I wanted to have all information in one series for the first posting, to
> avoid people having to look around too much if they want to give it a try.
>
> I'll post seperate series in the future.

Thanks.

> >> Patches:
> >> - [PATCH 1/2] kexec: Let slurp_file_len() return the number of bytes
> >> - [PATCH 2/2] kexec: Add preliminary m68k support
> >>
> >> Notes:
> >> - Based on git://git.kernel.org/pub/scm/utils/kernel/kexec/kexec-tools.git
> >
> > A good choice.
>
> Is it normal I don't see much activity there?

Yes, that is normal.

>
> >> - The ramdisk is loaded at the top of memory minus 4096, unlike with
> >> m68boot (ataboot/amiboot), as locate_hole() seems to have a bug that it
> >> cannot reserve a block at the real top of memory.
> >
> > Is this a bug that could be fixed?
>
> Possibly. I suspect an off-by-one bug somewhere, but I haven't looked deeply
> into it.

My feeling is that if possible it would be better to fix the bug than add a
work-around.

> >> - Do we want to check the struct bootversion at the start of the kernel,
> >> like m68kboot does?
> >> Kexec may be used to load ELF files that are not Linux kernel images,
> >> and thus don't have a Linux-specific struct bootversion.
> >
> > If the check can sanely be skipped for non Linux kernel images then
> > this sounds like a reasonable idea to me. Otherwise I would lean towards
> > omitting it. Either way, I don't feel strongly about this.
> >
> >> - Do we want to check the size of the kernel image + bootinfo, and warn the
> >> user if it's larger than 4 MiB?
> >> This is a limitation of the current Linux/m68k kernel only.
> >
> > I think that sounds like a good idea but I don't feel strongly about it.
>
> Currently I'm leaning towards just printing a warning for both
> (missing/incompatible
> bootversion and image-too-large).

That sounds fine to me.