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

[Tom Rini]

On Tue, Jul 16, 2024 at 10:14:26PM +0200, Heinrich Schuchardt wrote:
> On 7/16/24 22:01, Tom Rini wrote:
> > On Tue, Jul 16, 2024 at 09:35:18PM +0200, Heinrich Schuchardt wrote:
> > > On 7/16/24 21:13, Tom Rini wrote:
> > > > On Thu, Jun 20, 2024 at 04:35:39PM -0500, Nishanth Menon 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 believe that fundamentally, this is a problem that exists beyond both
> > > > just "U-Boot needs some binaries" and "TI has some binaries that
> > > > bootloaders need". So a generic solution is appropriate, and some sort
> > > > of community-based hosting of these needs (with appropriate licensing
> > > > from the IP owners) makes sense. Looking around at the binaries I have
> > > > to keep locally to use NXP platforms, and TI platforms and Rockchip
> > > > platforms, it's far from ideal. Having one place to get them all from
> > > > would make life easier for a lot of developers and also frankly for a
> > > > lot of end customers of these chips.
> > > > 
> > > 
> > > Some thought needs to be given to the license implications of these binaries
> > > for operating system distributions.
> > > 
> > > A distro providing a combined binary consisting of U-Boot and closed source
> > > firmware might be interpreted as conflicting with U-Boot's GPL license.
> > > 
> > > Distributing the closed source binaries and U-Boot in separate packages
> > > according to their respective licenses and only assemble them on the target
> > > device via a post-installation script might be allowable.
> > 
> > For this project the question is making sure that the binaries are
> > licensed such that they could be externally redistributable.
> > 
> > I don't know why someone would suggest that ABI calls are suddenly
> > linkage as I thought that (as far as these matters go) that was already
> > settled, but I am not a lawyer.
> 
> The relevant term in the GPL 2.0 license is "work based on the Program".
> According to the GPL a "work based on the Program" is "a work containing the
> Program or a portion of it".
> 
> If you build a binary via binman that contains U-Boot and another binary,
> the resulting binary could be considered "a work containing the Program or a
> portion of it".
> 
> The GPL 2.0 requires:
> 
> "But when you distribute the same sections as part of a whole which is a
> work based on the Program, the distribution of the whole must be on the
> terms of this License, whose permissions for other licensees extend to the
> entire whole, and thus to each and every part regardless of who wrote it."

I'm not a lawyer and I don't pretend to be one on mailing lists, either.

In that my non-lawyer statements matter, I don't think binman
constitutes some new form of linking and I believe it falls in to the
same well known ABI exception.

But that's entirely unrelated to the question of hosting binaries (some
of which may be closed source) for use in firmware projects, some of
which will not be GPL. For example, I would assume that running
tianocore on i.MX8 requires the same assorted binaries that U-Boot does,
and that would not have a license conflict.

-- 
Tom
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