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

Miquel Raynal
2018-06-08T07:36:51Z

Hi Simon,

On Thu, 7 Jun 2018 16:25:28 -0800, Simon Glass <sjg@chromium.org> wrote:

> Hi Miquel,
>
> On 6 June 2018 at 23:38, Miquel Raynal <miquel.raynal@bootlin.com> wrote:
> > Hello,
> >
> > Sorry for the delay.
> >
> > On Sat, 2 Jun 2018 10:15:17 -0600, Simon Glass <sjg@chromium.org> wrote:
> >
> >> Hi Tom,
> >>
> >> On 1 June 2018 at 11:55, Tom Rini <trini@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@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@chromium.org>
> >> > > > Signed-off-by: Tom Rini <trini@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.

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?

>
> 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.

> 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?

Thanks,
MiquÃ¨l