Request for hosting a boot-firmware repository in u-boot git (denx and GitHub)

Fri Jun 21 09:35:11 CEST 2024

On Fri, 21 Jun 2024 at 00:05, Simon Glass <sjg at chromium.org> wrote:
>
> Hi Nishanth,
>
> On Thu, 20 Jun 2024 at 15:35, Nishanth Menon <nm at ti.com> wrote:
> >
> > Hi Team,
> >
> > We have briefly discussed this topic on IRC[1]. I would like to
> > propose a new boot-firmware repository similar to the Linux-firmware
> > repository under the aegis of u-boot hosting.
> >
> > In addition to TI, it looks like some NXP[2] and Rockchip[3]
> > platforms seem to require additional closed-source/open-source
> > binaries to have a complete bootable image. Distribution rights and
> > locations of these binaries are challenging, and there needs to be a
> > standard for how and where they are hosted for end users.
> >
> > Further, looking ahead to future architectures:
> > * IP firmware: More and more IP vendors are embedding their own
> >   "specialized controllers" and require firmware for the operation
> >   (similar to Rockchip's DDR controller, I guess),
> > * boot stage firmware: Additional stages of the boot process involve
> >   vendor intermediate firmware, such as power configuration.
> > * Security enclave binaries: While I see a few folks trying to have an
> >   open-source s/w architecture, many PKA and PQC systems still require
> >   prop binaries for IP reasons.
> >
> > NOTE: I am not judging any company(including TI) for reasons why some
> > firmware is proprietary, but I hate to have the end users and other
> > system (distro) maintainers have to deal with hell trying to make the
> > life of end users easy to live with.
> >
> > In the case of TI's K3 architecture devices, we have two binary blobs
> > that are critical for the boot process.
> >
> > 1. TIFS Firmware / DMSC firmware[4]—This is the security enclave
> >   firmware. It is often encrypted, and sources are not public (due to
> >   various business/regulatory reasons).
> > 2. DM Firmware[5] - There is a source in public in some cases and
> >   binary only in others - essentially limited function binary to be
> >   put up in the device management uC. In cases where the source is
> >   available, the build procedure is, in my personal opinion, pretty
> >   arcane, and even though in theory it is practical, in practice, not
> >   friendly - efforts are going to simplify it, even probably integrate
> >   it with a more opensource ecosystem, but that is talking "look at the
> >   tea leaves" stuff.
> > 3. Low Power Management (LPM) binaries: tifs stub: another encrypted
> >   binary that gives the tifs system context restore logic before
> >   retrieving tifs firmware and a corresponding DM restoration binary.
> >
> > All told, this is not unlike the situation that necessitated the
> > creation of a Linux firmware repository.
> >
> > Options that I see:
> >
> > 1. Let the status quo be - SoC vendors maintain random locations and
> >   random rules to maintain boot firmware.
> > 2. Ask Linux-firmware to host the binaries in a single canonical
> >   location
> > 3. Host a boot-firmware repository - u-boot repo may be the more
> >   logical location.
> >
> > * (1) isn't the correct answer.
> >
> > * (2) Though I haven't seen any policy from the Linux-firmware
> >   community mandating anything of the form, the binaries we are talking
> >   of may not belong to Linux-firmware as they aren't strictly speaking
> >   something Linux kernel will load (since the bootloader has that
> >   responsibility), and in some cases may not even directly talk to
> >   (security enclave or DDR firmware stuff). I am adding Josh to this
> >   mail to see if he has any opinions on the topic (but keeping
> >   from cross posting on linux-firmware list, unless folks feel it is
> >   OK).
> >
> > On (3):
> > Proposal:
> >
> > * Create a boot firmware repository in Denx and/or GitHub (if
> >   financials are a hurdle, I hope we can solve it as a community).
> > * Limit binaries only to those consumed part of the u-boot scope.
> >
> > * Limit binaries only to those that do not have an opensource project
> >   (Trusted Firmware-A/M, OP-TEE, etc..) or depend entirely on vendor
> >   source or are binary only in nature (subject to licensing terms below)
> > * Limit binaries to some pre-established size to prevent repository
> >   explosion - say, 512Kib?
> > * Follow the same rules of integration and licensing guidelines as
> >   Linux-firmware[6].
> > * Similar rules as Linux-firmware guidelines of ABI backward and
> >   forward compatibility.
> > * Set a workflow update flow and a compatibility requirements document
> >
> > If we agree to have boot firmware under the stewardship of u-boot, we
> > should also set other rules, which is excellent to discuss.
> >
> > Thoughts?
>
> I suggest:
>
> 4) Add a 'binman blob' subcommand which can fetch blobs, similarly to
> how 'binman tool -f xxx' features a tool, using the image description
> to know what is needed and some configuration for where to find it /
> how to build it.

This is a solving a different problem IMO. Also most distros build in
constrained environments so pulling FW randomly with a tool in the
build process won't work. Also most users won't want to pull the
latest each time they build, most vendors will choose a static set of
versions and only bump to deal with bugs, CVEs or explicit features
they need rather than having a series of moving targets.

Well the whole point of the repo is to remove the guesswork, it would
be a set of firmware that is expected to work in a single location.

> IMO the actual repo is not the ultimate goal here. Building and
> testing should be the ultimate goal.

I disagree, the repo would assist working and tested firmware because
there could be a review/test process as part of it to ensure things
work and are tested to give users a good experience rather than having
to search the web and forum posts to attempt to find pieces that work
together.

> >
> > [1] https://libera.irclog.whitequark.org/u-boot/2024-06-13#36498796;
> > [2] https://docs.nxp.com/bundle/AN14093/page/topics/build_the_u-boot.html
> > [3] https://bbs.t-firefly.com/forum.php?mod=viewthread&tid=2236
> > [4] https://git.ti.com/cgit/processor-firmware/ti-linux-firmware/tree/ti-sysfw?h=ti-linux-firmware
> > [5] https://git.ti.com/cgit/processor-firmware/ti-linux-firmware/tree/ti-dm?h=ti-linux-firmware
> > [6] https://docs.kernel.org/next/driver-api/firmware/firmware-usage-guidelines.html
> > --
> > Regards,
> > Nishanth Menon
> > Key (0xDDB5849D1736249D) / Fingerprint: F8A2 8693 54EB 8232 17A3  1A34 DDB5 849D 1736 249D
>
> Regards,
> SImon