[PATCH 23/34] bootstd: Maintain a list of images

[Simon Glass]

Hi Tom,

On Fri, 18 Oct 2024 at 12:04, Tom Rini <trini at konsulko.com> wrote:
>
> On Fri, Oct 18, 2024 at 11:20:52AM -0600, Simon Glass wrote:
> > Hi Tom,
> >
> > On Fri, 18 Oct 2024 at 10:33, Tom Rini <trini at konsulko.com> wrote:
> > >
> > > On Fri, Oct 18, 2024 at 09:01:03AM -0600, Simon Glass wrote:
> > > > Hi Heinrich,
> > > >
> > > > On Thu, 17 Oct 2024 at 22:07, Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> > > > >
> > > > >
> > > > >
> > > > > Am 18. Oktober 2024 01:24:02 MESZ schrieb Simon Glass <sjg at chromium.org>:
> > > > > >We want to keep track of images which are loaded, or those which could
> > > > > >perhaps be loaded. This will make it easier to manage memory allocation,
> > > > > >as well as permit removal of the EFI set_efi_bootdev() hack.
> > > >
> > > > I'll change this 'hack' to 'feature'.
> > > >
> > > > >
> > > > > Please, keep in mind that files can be loaded manually, e.g. via the dhcp, the wget, and the loady commands. These are outside bootflows.
> > > >
> > > > Yes, this series is only going to help if bootstd is used. For ad-hoc
> > > > use, EFI will need to rely on the above feature, at least until
> > > > someone can think of another solution.
> > >
> > > Perhaps I need to try and be clearer here than I might have been in the
> > > past. The consensus among off the shelf free software operating systems
> > > is "just give me an EFI interface". This simplifies things on their end
> > > if regardless of architecture it's the same interface. This means that
> > > in U-Boot we need to treat EFI as one of the primary interfaces. Not a
> > > novelty. Not a "some people might use". It is a frequent and commonly
> > > used feature.
> >
> > Yes, EFI is everywhere and growing. All the more reason to tidy up
> > this piece. I would like to see bootmgr use this new API, for example.
> >
> > But how does this comment affect this patch?
>
> Because at the very high level, I wonder if I made a mistake a few years
> back. As I understand it, the nominal case is "bootefi bootmgr". I was
> saying at the time that perhaps bootstd can just fire that off, and move
> on. Now it seems like we're going along the path of re-inventing that,
> and not integrating well with it either.

In what way are we re-inventing that? bootstd supports lots of
different ways of booting, not just EFI. Also I hope that one day EFI
will be implemented more as part of U-Boot than as a bolt-on, so will
make use of bootflows, etc.

>
> So, to try and bring things back together. If U-Boot decides to load
> $FOO from device $BAR, at that common point is where we need to:
> - Is there an lmb for the location this is supposed to go to (for the if
>   we know it, entire size)?
> - Note down everything else we know, now.

Yes.

>
> This means that we can note down enough stuff so that EFI can construct
> the path it needs. And if we're being told a filesystem, that filename
> is good enough for the IH_TYPE thing you're wanting, or at least a good
> chunk of it I hope.

You want me to ignore the type that I know (kernel, ramdisk, logo,
etc.) and infer the type from a filename? Why?

For EFI there is only an EFI application. It will always just be a PE
file. We don't really know what it is, as someone pointed out earlier.
Maybe one day we will check to see if it is a UKI and pull things out
of it. But then, it would be component parts (kernel, ramdisk, etc.)
so I would want to add them as images.

>
> It also means that since it's at the most common point, it doesn't
> matter if we were in an EFI application, a boot script, a bootmeth or
> someone at the cmdline doing "load mmc 0:1 /boot/Image $kernel_addr_r".

For that case (at the cmdline), bootstd is not currently running. Are
you suggesting that bootstd could pick up these things and record
them? If so, then yes, definitely, I want to do that. This series is
the starting point for that. If you are suggesting something else,
then I think I have lost you at this point.

Regards,
Simon