Preliminary kexec support for Linux/m68k

[Geert Uytterhoeven]

Hi Simon,

Thanks for your comments!

On Thu, Sep 19, 2013 at 11:07 PM, Simon Horman <horms at 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.

>> 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?

>>   - 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.

>>   - 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).

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds