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

[Simon Glass]

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.

>
> 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 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.

>
>> 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.

Regards,
Simon