[U-Boot] [PATCH] sandbox_flattree: Switch to TPMv2 support

Sat Jun 9 13:30:54 UTC 2018

Hi Simon,

On Fri, 8 Jun 2018 13:59:07 -0800, Simon Glass <sjg at chromium.org> wrote:

> Hi Miquel,
> 
> On 7 June 2018 at 23:36, Miquel Raynal <miquel.raynal at bootlin.com> wrote:
> > Hi Simon,
> >
> > On Thu, 7 Jun 2018 16:25:28 -0800, Simon Glass <sjg at chromium.org> wrote:
> >  
> >> Hi Miquel,
> >>
> >> On 6 June 2018 at 23:38, Miquel Raynal <miquel.raynal at bootlin.com> wrote:  
> >> > Hello,
> >> >
> >> > Sorry for the delay.
> >> >
> >> > On Sat, 2 Jun 2018 10:15:17 -0600, Simon Glass <sjg at chromium.org> wrote:
> >> >  
> >> >> Hi Tom,
> >> >>
> >> >> On 1 June 2018 at 11:55, Tom Rini <trini at konsulko.com> wrote:  
> >> >> >
> >> >> > On Fri, Jun 01, 2018 at 09:25:19AM -0600, Simon Glass wrote:  
> >> >> > > +Miquel due to sandbox TPM issue
> >> >> > >
> >> >> > > Hi Tom,
> >> >> > >
> >> >> > > On 25 May 2018 at 06:27, Tom Rini <trini at konsulko.com> wrote:  
> >> >> > > > In order to have the test.py tests for TPMv2 run automatically we need
> >> >> > > > to have one of our sandbox builds use TPMv2 rather than TPMv1.  Switch
> >> >> > > > sandbox_flattree over to this style of TPM.  
> >> >> > >
> >> >> > > The problem seems to be that the sandbox driver is only built with
> >> >> > > either TPMv1 or TPMv2. It needs to be able to build with both, so we
> >> >> > > can run tests with both.  
> >> >> >
> >> >> > Right.  But we don't have any run-time automatic tests for TPMv1 as the
> >> >> > 'tpm test' command needs to be done manually, at least today (unless I'm
> >> >> > missing something under test/py/tests/).  And we can't (functionally in
> >> >> > real uses) have both TPM types available.  Perhaps we should make TPMv2
> >> >> > the default for sandbox?  All of the TPMv1 code will still be getting
> >> >> > build-time exercised due to platforms with TPMv1 on them.  
> >> >>
> >> >> I'll take a look at this. It should actually be quite easy to have two
> >> >> TPMs in sandbox, one v1 and one v2. At least I don't know of any
> >> >> impediment.
> >> >>  
> >> >> >  
> >> >> > > It really doesn't make any sense to have build-time branches for sandbox.
> >> >> > >
> >> >> > > We currently have:
> >> >> > >
> >> >> > > sandbox - should be used for most tests
> >> >> > > sandbox64 - special build that forces a 64-bit host
> >> >> > > sandbox_flattree - builds with dev_read_...() functions defined as
> >> >> > > inline. We need this build so that we can test those inline functions,
> >> >> > > and we cannot build with both the inline functions and the non-inline
> >> >> > > functions since they are named the same
> >> >> > > sandbox_noblk - builds without CONFIG_BLK, which means the legacy
> >> >> > > block drivers are used. We cannot use both the legacy and driver-model
> >> >> > > block drivers since they implement the same functions
> >> >> > > sandbox_spl - builds sandbox with SPL support, so you can run
> >> >> > > spl/u-boot-spl and it will start up and then load ./u-boot. We could
> >> >> > > probably remove this and add SPL support to the vanilla sandbox build,
> >> >> > > since people can still run ./u-boot directly
> >> >> > >
> >> >> > > At present there are unnecessary config differences between these
> >> >> > > builds. This is explained by the fact that it is a pain for people to
> >> >> > > have to add configs separately to each defconfig. But we should
> >> >> > > probably make them more common. I will take a look.  
> >> >> >
> >> >> > OK.
> >> >> >  
> >> >> > > What do you think about dropping sandbox_spl and make sandbox build
> >> >> > > SPL? It does take slightly longer to build, perhaps 25%.  
> >> >> >
> >> >> > That's fine with me.
> >> >> >  
> >> >> > > > Cc: Simon Glass <sjg at chromium.org>
> >> >> > > > Signed-off-by: Tom Rini <trini at konsulko.com>
> >> >> > > > ---
> >> >> > > > I'm tempted to switch the main sandbox target over instead as I don't
> >> >> > > > quite see where we're running the tpm1.x tests automatically.  Would
> >> >> > > > that be a better idea?
> >> >> > > > ---  
> >> >> > >
> >> >> > > Miquel, can we adjust the code to build both TPMv1 and v2 for sandbox,
> >> >> > > and select at run-time?  
> >> >> >
> >> >> > I thought we had talked about that before and couldn't easily?  One
> >> >> > thing I am a bit wary of is adding indirection for build coverage sake.  
> >> >>
> >> >> Yes, I am hoping that it is just different drivers with the same API
> >> >> but perhaps I am going to be disappointed.  
> >> >
> >> > Indeed, both versions share the same 'architecture' but quite a few
> >> > structures/functions are defined differently for each TPM flavour in
> >> > different files. What makes the magic are the
> >> > #ifdef TPM_V1
> >> > #else
> >> > #endif
> >> > blocks around includes, making them mutually exclusive.
> >> >
> >> > Choice has been made not to use both flavours at the same time in the
> >> > second series, when I clearly made a separation between v1 code and v2
> >> > code. Trying to compile them both with just some Kconfig hacks would
> >> > simply not work IMHO.
> >> >
> >> > My apologies for not being helpful at all... As Tom said, there are no
> >> > tests running on v1 code so maybe it's better to exercise v2 code in
> >> > Sandbox and let people compile-test the former on their own?  
> >>
> >> I had a play with this and it does not seem too tricky.
> >>
> >> With a bit of fiddling I got it to build except for this:
> >>
> >> /home/sjg/c/src/third_party/u-boot/files/cmd/tpm-v2.c:324: multiple
> >> definition of `get_tpm_commands'  
> >
> > That's one problem. I'm pretty sure at some point we will need to
> > declare differently tpm_chip_priv depending on the version. Using two
> > structures in an enumeration could be the way to handle it.  
> 
> I think you can just remove the #ifdef from inside struct
> tpm_chip_priv - it's not really a nice thing to do anyway.

Ok.

> 
> >
> > Another point is that doing so, you embed twice the code and symbols
> > than what's really needed. Is not having mutually exclusive
> > code better than enlarging U-Boot binary?  
> 
> The sandbox binary is enormous since it enables as many features as it
> can. We can always create a minimal sandbox if it becomes useful, but
> for now sandbox is mostly for testing.

I meant for all the platforms. But you are right that this double
selection should only happen for Sandbox.

> 
> >  
> >>
> >> I think if you adjust it to check the driver version (v1 or v2), then
> >> you can use either the v1 or v2 command set. You could move the
> >> get_tpm_commands function into the uclass so it can check the driver.  
> >
> > It means patching all drivers if we want to do it cleanly.  
> 
> Yes, you could have a field that needs to be set so that the uclass
> knows which version it is. Alternatively if you want to save a patch
> you could have an is_v2 bool, which defaults to 0 for v1 drivers.

Maybe an enum would be better. 0 would still mean a v1 driver.

> 
> >  
> >> As to whether the driver is v1 or v2, I wonder if the driver could set
> >> a 'version' flag in tpm_chip_priv() ?  
> >
> > Probably.
> >  
> >> I really don't like the idea of having mutually exclusive code in
> >> driver model, so it would be good to fix this.  
> >
> > I'll be away the next weeks, so I won't work on it before end of June.
> > Can you share a diff of your changes?  
> 
> Yes I pushed a patch to u-boot-dm branch tpm-working.

Thanks!

> 
> Regards,
> Simon

Regards,
Miquèl

-- 
Miquel Raynal, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com