Re: [PATCH v4 00/33] Initial implementation of standard boot

Tom Rini
2022-03-23T19:30:28Z

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On Wed, Mar 23, 2022 at 08:21:22PM +0100, Michael Nazzareno Trimarchi wrote:
> Hi Tom
>
> On Wed, Mar 23, 2022 at 7:46 PM Simon Glass <sjg@chromium.org> wrote:
> >
> > Hi Tom,
> >
> > On Wed, 23 Mar 2022 at 08:05, Tom Rini <trini@konsulko.com> wrote:
> > >
> > > On Sun, Mar 06, 2022 at 05:49:43AM -0700, Simon Glass wrote:
> > > >
> > > > The bootflow feature provide a built-in way for U-Boot to automatically
> > > > boot an Operating System without custom scripting and other customisation.
> > > > This is called 'standard boot' since it provides a standard way for
> > > > U-Boot to boot a distro, without scripting.
> > > >
> > > > It introduces the following concepts:
> > > >
> > > > - bootdev - a device which can hold a distro
> > > > - bootmeth - a method to scan a bootdev to find bootflows (owned by
> > > > U-Boot)
> > > > - bootflow - a description of how to boot (owned by the distro)
> > > >
> > > > This series provides an implementation of these, enabled to scan for
> > > > bootflows from MMC, USB and Ethernet. It supports the existing distro
> > > > boot as well as the EFI loader flow (bootefi/bootmgr). It works
> > > > similiarly to the existing script-based approach, but is native to
> > > > U-Boot.
> > > >
> > > > With this we can boot on a Raspberry Pi 3 with just one command:
> > > >
> > > > bootflow scan -lb
> > > >
> > > > which means to scan, listing (-l) each bootflow and trying to boot each
> > > > one (-b). The final patch shows this.
> > > >
> > > > With a standard way to identify boot devices, booting become easier. It
> > > > also should be possible to support U-Boot scripts, for backwards
> > > > compatibility only.
> > > >
> > > > This series relies on the PXE clean-up series, posted here:
> > > >
> > > > https://patchwork.ozlabs.org/project/uboot/list/?series=267078
> > > >
> > > > For documentation, see the 'doc' patch.
> > > >
> > > > For version 2, a new naming scheme is used as above:
> > > >
> > > > - bootdev is used instead of bootdevice, because 'device' is overused,
> > > > is everywhere in U-Boot, can be confused with udevice
> > > > - bootmeth - because 'method' is too vanilla, appears 1300 times in
> > > > U-Boot
> > > >
> > > > Also in version 2, drivers are introduced for the boot methods, to make
> > > > it more extensible. Booting a custom OS is simply a matter of creating a
> > > > bootmeth for it and implementing the read_file() and boot() methods.
> > > >
> > > > Version 4 makes some minor improvements and leaves out the RFC patch for
> > > > rpi conversion, in the hope of getting the base support applied sooner
> > > > rather than later.
> > > >
> > > > The design is described in these two documents:
> > > >
> > > > https://drive.google.com/file/d/1ggW0KJpUOR__vBkj3l61L2dav4ZkNC12/view?usp=sharing
> > > >
> > > > https://drive.google.com/file/d/1kTrflO9vvGlKp-ZH_jlgb9TY3WYG6FF9/view?usp=sharing
> > >
> > > I keep putting off commenting more here, but, I still feel this is the
> > > wrong direction. What problems do we have today with distro boot?
> > > Well, we haven't figured out how to move configuring it out of the board
> > > config.h file. But that's just one of a half dozen or so examples of
> > > how we haven't figured out a good solution to configuring the default
> > > environment. And only some of those other examples are boot related
> > > (the NXP chain of trust booting stuff is another boot example, ETHPRIME,
> > > HOSTNAME, etc, are non-boot examples).
> > >
> > > We also aren't improving testing of "can we boot" here, because what
> > > THAT needs is setting up LAVA and booting some installers on some
> > > hardware (and some QEMU). That's testing that Linux boot works. Today
> > > we have tests for hush parsing, and if distro boot makes use of
> > > something we don't have a test for, we need a test for it. This adds
> > > tests for itself, which is good.
> > >
> > > And I still don't see an example of where this demonstrates that
> > > existing non-UEFI boot cases are now easier to handle or cleaner to
> > > handle or otherwise better.
> > >
> > > In that this is an attempt to tackle one of the long standing needed
> > > migrations (be able to drop board config.h files), something here needs
> > > doing. But I don't see this as the right direction, sorry.
> >
> > Does anyone have a better idea for all of this? This is a solid base
> > we can build on but we can't make any progress while this is just
> > patches. What not apply it and we can move forward?
> >
>
> I agree with Simon. Having a well documented flow, help to integrate
> products and have a standard
> way to handle the booting flow
>
> > - solves the env problem for distro boot in that we don't need the scripts
> > - gets rid of the scripts which are a confusing mess
> > - provides proper high-level concepts of boot device and boot method
> > - allows testing of the U-Boot part of 'can we boot' because we have
> > tests for all the cases - we can expand this over time
> > - allows non-UEFI boot cases like Chrome OS, which is currently just a
> > hack for one board[1]
> > - provides a programmatic base for A/B boot, etc.
> >
> > I feel the same way with Takahiro's series, which has been out-of-tree
> > for too long.
>
> I don't see the problem in having it merged. I'm dealing every day
> with crazy script
> to handle situation like [1] and I think that company that integrates
> their product can
> benefits on those changes. They can be improved with other people
> wants to use it
> in their products.
>
> Michael
>
> >
> > Please reconsider this. What do we have to lose?
> >
> > Regards,
> > Simon
> >
> > [1] CONFIG_BOOTCOMMAND="tpm init; tpm startup TPM2_SU_CLEAR; read mmc
> > 0:2 100000 0 80; setexpr loader *001004f0; setexpr size *00100518;
> > setexpr blocks $size / 200; read mmc 0:2 100000 80 $blocks; setexpr
> > setup $loader - 1000; setexpr cmdline_ptr $loader - 2000; setexpr.s
> > cmdline *$cmdline_ptr; setexpr cmdline gsub %U \\\\${uuid}; if part
> > uuid mmc 0:2 uuid; then zboot start 100000 0 0 0 $setup cmdline; zboot
> > load; zboot setup; zboot dump; zboot go;fi"

OK, and what does your example here look like on top of Simon's series?
Or do you just mean ChromeOS boot?

--
Tom

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