[PATCH v8 00/13] bootstd: Convert rockchip and add various fixes and tweaks

[Simon Glass]

Hi Tom,

On Sun, 9 Apr 2023 at 03:14, Tom Rini <trini at konsulko.com> wrote:
>
> On Sat, Apr 08, 2023 at 12:08:37PM +1200, Simon Glass wrote:
> > Hi Tom,
> >
> > On Sat, 8 Apr 2023 at 09:55, Tom Rini <trini at konsulko.com> wrote:
> > >
> > > On Sat, Apr 08, 2023 at 09:35:48AM +1200, Simon Glass wrote:
> > > > Hi Tom,
> > > >
> > > > On Sat, 8 Apr 2023 at 08:22, Tom Rini <trini at konsulko.com> wrote:
> > > > >
> > > > > On Sat, Apr 08, 2023 at 07:53:10AM +1200, Simon Glass wrote:
> > > > > > Hi Tom,
> > > > > >
> > > > > > On Sat, 8 Apr 2023 at 07:39, Tom Rini <trini at konsulko.com> wrote:
> > > > > > >
> > > > > > > On Fri, Apr 07, 2023 at 10:36:38PM +1200, Simon Glass wrote:
> > > > > > >
> > > > > > > > This series converts rockchip boards over to use standard boot. It also
> > > > > > > > fixes various problems which have come up recently, showing differences
> > > > > > > > between the current implementation and the distroboot scripts.
> > > > > > > >
> > > > > > > > This should get us closer to being able to turn down the scripts.
> > > > > > >
> > > > > > > Alright, so I grabbed a few parts of this series to investigate the
> > > > > > > points I'm trying to grasp better, and I think this is going the wrong
> > > > > > > track. We should start off by dropping "default y" from BOOTSTD, and
> > > > > > > then start adding "default y if" for SoCs as we convert them. The end
> > > > > > > goal should be that we get to the point where we can "default y if ARM
> > > > > > > || RISCV || X86" or perhaps "default y !(PPC || M68K || ...)" as it's
> > > > > > > just a few architectures that haven't ended up being converted. But
> > > > > > > today, there's too much churn on platforms that aren't making any use of
> > > > > > > this. And I don't think this is going to be functionally worse than all
> > > > > > > of the places we "imply DISTRO_DEFAULTS" today, as functionally we can
> > > > > > > replace that with "imply BOOTSTD" as they get migrated.
> > > > > >
> > > > > > That would really be a backward step. I'm not sure what to say at this
> > > > > > point. I've put a lot of effort in trying to get this over the line,
> > > > > > but the only way we get feedback is when it is applied.
> > > > >
> > > > > Having bootstd enabled and not functional (because boot_targets aren't
> > > > > set) isn't helping the migration happen. And the hard part of the
> > > > > migration isn't knowing it's possible, or enabling 1-2 options, it's
> > > > > testing it and also it really just being 1-2 options.
> > > >
> > > > Standard boot does not need boot_targets to be set. It works fine
> > > > without it. It just goes through the boot devices in a pre-defined
> > > > order, from fastest to slowest. It matches what most boards do anyway.
> > > > The main reason we kept it is for compatibility with distro boot.
> > >
> > > What most boards do today is just sit at the prompt and wait for input,
> > > which this changes, which is part of the big source of size churn here.
> >
> > Yes.
> >
> > >
> > > > I don't think testing in advance is a feasible approach in general.
> > > > See for example the rpi series which hasn't got any comment. It likely
> > > > won't until it is applied. That's how we get feedback. We have months
> > > > to resolve issues and I believe that the code is fundamentally sound.
> > >
> > > We need some spot testing here and there to see how things react and how
> > > people use it. You found a lot of things with just rk3399, and now the
> > > rest of rockchip looks to be fairly direct. You found more things doing
> > > x86. When you can convert some other SoC and the change is just dropping
> > > distro_bootcmd and calling bootflow scan instead (or that + setting the
> > > order again), that'll be good.
> >
> > So long as we are aware that we generally only find problems when
> > patches land, yes. The QEMU stuff is easier since it doesn't need a
> > board. It's also not all that useful in the real world :-) I'd like to
> > try a programmatic conversion, too, although I haven't looked at it
> > yet.
>
> Well, I think you're misjudging when we get most of the testing done.
> It's at that last one or two -rc points where it seems people test
> things, and surprises are very much not welcome then, which is why I
> want more unit testing of things like this.  Especially as we're just
> getting started on the conversions.

The unit tests are in test/boot and there's quite a bit. But it does
not cover some of the minor details though, e.g. how the fdt file is
selected. It can certainly be added, once we know what the correct
behaviour is. I think it needs more users, before I can tell how close
we are.

The nice thing with bootstd is that we can create unit tests for this
behaviour. That isn't possible with the scripts.

>
> > > But I'm not sure that changing the platforms that don't today opt-in to
> > > distro_bootcmd (which has been a thing for a long time now) to force
> > > opt-in to this is the right call. It might be in some cases (mediatek
> > > maybe? Or maybe no, everyone does android of some flavour so a different
> > > bootstd option) but not others (those *_evm_r5_defconfig boards).
> >
> > Fair enough, so long as we actually turn down distro_bootcmd. So long
> > as it is still there, boards will enable it. See SPL_FIT_GENERATOR.
>
> Yes, it will take follow-through to get everyone converted, and making
> sure the new tool covers all the use cases.
>
> > > > > > What churn are you seeing? Do you mean:
> > > > > >
> > > > > > disable BOOTSTD for boards with custom commands? You asked for that patch
> > > > > > disabling BOOTSTD_DEFAULTS? You asked for that patch
> > > > > > enable BOOTSTD_DEFAULTS by default? We can drop it if you like
> > > > >
> > > > > We need all 3 of those patches because without the 3rd you don't get a
> > > > > good experience when you do enable bootstd for a platform. The problem
> > > > > is that unless you have distro_bootcmd today you're getting between 63kB
> > > > > (a lot of mediatek platforms) and 5k (silk, as a semi-random example) of
> > > > > growth because bootstd is on and now is the default bootcmd, when before
> > > > > they had nothing. And probably had board docs saying "now do ... to
> > > > > boot". And that's largely setting aside the *_r5_* platforms that I know
> > > > > are just doing something else, and could disable it.
> > > >
> > > > Er, I thought you wanted it to default on if the boards has no
> > > > bootcmd? If not, we can disable it for those as well. If you don't
> > > > want any increase we can disable it for boards without DISTRO_DEFAULTS
> > > > too. After all, presumably those boards are doing something custom
> > > > anyway.
> > >
> > > I think I might have originally, but now that I'm looking at the results
> > > it was too optimistic. Every branch I build I look at the per-board
> > > breakdown, not just the summary. And it's too much on all of these
> > > platforms that had no default bootcmd today.
> >
> > OK. I don't mind about that. We've ended up in a bit of a rabbit hole I think.
> >
> > >
> > > > > We want to convert everyone doing distro_bootcmd over to this, that's
> > > > > good. The problem is we don't have a symbol today that means "we want
> > > > > distro_bootcmd" and also isn't overloaded (DISTRO_DEFAULTS is overloaded
> > > > > in this sense).
> > > > >
> > > > > The wrong direction part of this series is that for platforms that
> > > > > aren't in the middle of converting we're increasing their size between
> > > > > somewhat and very very much, and we haven't tested that it'll work. And
> > > > > yes, there's some automatic guessing logic, which hasn't been tested on
> > > > > these platforms either, so we don't actually know if going from no
> > > > > bootcmd (and so drops to prompt) to attempts to autoboot something is an
> > > > > improvement.
> > > >
> > > > So, the wrong direction comes from the last three patches. Is that right?
> > >
> > > The wrong direction comes from enabling bootstd (and so, a bootcmd and
> > > distro boot) on platforms that just sit at the prompt today.  We are not
> > > making a good heuristic guess at what the should be doing.  Reaching out
> > > to the maintainers to get them to do the conversion, especially once
> > > it's just a matter for most of them of just enabling bootstd and then
> > > distro, if they want that or once bootmeth android gets done, for those
> > > platforms) is how we get them moved smoothly.
> >
> > We should know which boards sit at the prompt today, by the fact that
> > they don't have a bootcmd. Presumably that is the way the maintainer
> > wants it, so I agree we should avoid changing it.
>
> Well, doing:
> for C in `(cd configs;ls)`;do make -sj $C && mv .config configs/$C;done
> to give me everyones full config to browse, there's 564 boards calling
> distro_bootcmd, but 465 of them are direct "run distro_bootcmd" and
> nothing more. Those are the ones that'll be easy to migrate, once we've
> got another migration or two done.

Hmm it would be nice if moveconfig let you summarise values of CONFIG vars.

Some of these will need tweaking, e.g. to replace the custom command
with something that uses bootstd.

>
> > > > Fundamentally the problem I have is that I know where I would like
> > > > this to head, which is everything using standard boot and turning down
> > > > the scripts. But it feels like every time I touch bootstd we have to
> > > > have the EFI discussion again. You can imagine how I feel about
> > > > disabling BOOTSTD by default...it would basically kill it.
> > >
> > > Well, we enabled bootstd by default too quickly perhaps then, and just
> > > like we narrowed down EFI_LOADER defaults, we need to narrow this down
> > > until it's easily convertable.
> >
> > It feels like it took a year to get that moving. There was so much EFI
> > discussion that I really don't want to revisit.
>
> Yes, and there too I started off with "well, this works for everyone,
> so, OK" and then saw that "Well, OK, a lot of things don't need/want
> that, really".
>
> > > > This is not really an arch-specific thing, nor an SoC-specific thing.
> > > > The underlying logic is the same for everything. The reason I think we
> > > > need to do a few cases before we enable it everywhere is that we need
> > > > to find the little tweaks needed in that logic.
> > >
> > > It's a generic framework to a board specific thing.
> > >
> > > > How about we apply the first patches in this series, skipping the last
> > > > three, then apply the rpi series as well. That should get people
> > > > actually using it and we can iron out the problems. It also keeps
> > > > things moving. We have months before the release.
> > > >
> > > > Enabling by default can come later once we decide what we want to do
> > > > about size increases, boards that don't use DISTRO_DEFAULTS and boards
> > > > that don't have a boot command.
> > >
> > > How about disabling it by default and imply'ing it for everything that
> > > implies/selects DISTRO_DEFAULTS today, since the part of bootstd that is
> > > done is the distro bootmeth?
> >
> > I'd really like to move forwards, instead of creating another barrier
> > to this migration. There was a huge amount of work in making sure that
> > the incremental size of bootstd was small, so it could be cheaply
> > enabled. This all went off the rails because, as you correctly pointed
> > out, enabling the bootstd commands does ~nothing if there is no actual
> > boot command set. I wish I had just stopped then to clarify the goals,
> > because this has all burned a lot of time and energy.
> >
> > From my side the best thing to do would be to get the currently
> > outstanding migrations into -master ASAP so people can try them out.
> > Despite the delays we still have months left for testing on this
> > release. Then I (or perhaps maintainers??) can work on some new ones
> > for -next when that opens.
>
> Yes, we can take the fixes in this series.  And yes, we can take
> finishing moving the rest of rockchip over, since I put in the line to
> make sure we still grab all of the defaults generic distro needs. And I
> am hopeful Peter will have the time to test the Pi conversion on all the
> hardware he wants to test it on (along with booting up whatever OS
> combinations).
>
> Another one of those big chunk of boards is the sunxi families, if you
> want to find some boards and boot some distros.

OK. Let's get rpi in and I can look at sunxi for -next

>
> > Once we get to the point where every bootstd series doesn't raise a
> > discussion about EFI, I will feel a lot more comfortable about
> > changing defaults. I hope you can understand that...
>
> Well, that's going to be the case until you've handed bootmeth_distro
> off to someone else, most likely.  Generic distro boot means EFI boot.
> And I only mentioned EFI here as an example of should have pushed back
> on "enable this for everyone" sooner.

Would someone like to take it over? Note that bootmeth_distro is just
the extlinux.conf stuff.

>
> Because that's the key here, on the 564 platforms that use
> distro_bootcmd today, there shouldn't be any growth when we switch to
> bootstd, and there's even more platforms that enable
> CONFIG_DISTRO_DEFAULTS than there are that use distro_bootcmd so the
> cases like xilinx mini should be the exception, not the rule.  And
> that's what I keep circling back to. The logic to keep the defaults that
> generic distro support needs are (almost) always already set on the
> platforms that are using generic distro boot, so we shouldn't grow in
> size when bootstd turns it on.  And if I'm changing my mind about
> forcing this on, on platforms that hadn't been doing generic distro
> before, I guess I'm changing my mind, sorry, there's too many platforms
> that are doing other things (not generic distro or Android or Special
> Things).

Yes I agree there should be no size growth for platforms which use
distro_bootcmd today and move to bootstd. That is easy enough to check
as part of migration. For the rpi and rockchip series the size reduces
from where we are today by 1-12KB. Re the bootstd default, we should
talk about that.

So basically, the plan for migrations is something like this:
- switch over some group of boards (change from DISTRO_DEFAULTS to
BOOTSTD_DEFAULTS in the process)
- test by booting various distros to see if there are new corner cases
(do we have a list?)
- check there is no size growth
- send patches
- discussion will focus on code review and testing

Does that sound right?

Do you think maintainers might be interested in migrating their boards?

Anyway, I'll resend the series without the last three patches which
generated this discussion.

As above I also see a bit of a gap in testing which would be good to
plug. The bootmeths rely on CI to test with two faked OS images. But
we might be able to add unit tests for these, with a bit of thought. I
will see what I can do.

Regards,
Simon