Re: [GIT PULL] tpmdd updates for v4.16

[Alexander Steffen]

On 10.01.2018 17:08, Jarkko Sakkinen wrote:
> On Tue, Jan 09, 2018 at 10:59:07AM +0100, Alexander Steffen wrote:
> > On 08.01.2018 12:18, Jarkko Sakkinen wrote:
> > > Hi James,
> > >
> > > Sorry for a late PR.
> > >
> > > Summary of the content:
> > >
> > > * Reduced polling delays in tpm_tis.
> > > * Support for retrieving TPM 2.0 Event Log through EFI before
> > >     ExitBootServices.
> > > * Replaced tpm-rng.c with a hwrng device managed by the driver for each
> > >     TPM device.
> > > * TPM resource manager synthesizes TPM_RC_COMMAND_CODE response instead
> > >     of returning -EINVAL for unknown TPM commands. This makes user space
> > >     more sound.
> > > * CLKRUN fixes:
> > >     * Keep #CLKRUN disable through the entier TPM command/response flow.
> > >     * Check whether #CLKRUN is enabled before disabling and enabling it
> > >       again because enabling it breaks PS/2 devices on a system where it
> > >       is disabled.
> >
> > I just spent some time trying to run all that (tpmdd-next-20180108) through
> > my test system and hit a couple of non-TPM problems. In case you see similar
> > issues, this is what I found out:
> >
> > 1. rmmod for the TPM driver hangs indefinitely. The TPM driver now registers
> > itself as a hwrng, but in case it is the only hwrng in a system, the call to
> > hwrng_unregister never returns. Known bug, but still not fixed in 4.15-rc7
> > (see https://www.mail-archive.com/linux-crypto@xxxxxxxxxxxxxxx/msg29884.html
> > for details).
> >
> > 2. Raspberry Pis (which I use to test tpm_tis_spi and
> > tpm_i2c_infineon) boot with that kernel, but have no USB or ethernet
> > support. Also a known problem
> > (http://lists.infradead.org/pipermail/linux-arm-kernel/2018-January/552280.html).
> >
> > 3. Device tree overlays with references to non-existent target-paths are
> > rejected now (whereas before the invalid parts were just ignored). I guess
> > this is an intentional change, but the error message does not really point
> > to the problem (applying the overlay just returns with EINVAL).
>
> Do we have these?

No, otherwise I would have sent a fix :)

It is just something that I used for my tests: I had an overlay that I 
could use for both the mainline kernel and the RPi kernel. On the RPi 
kernel it would deactivate the spidev entry, so that tpm_tis_spi was 
able to use the device. On the mainline kernel, there is no spidev in 
the device tree, so this part is not necessary and I simply removed it 
now to fix the problem (I'm not using the RPi kernels anymore).

Alexander

> > With all that fixed in my environment, my tests now pass successfully.
> >
> > Alexander
>
> Thank you for reporting these issues.
>
> /Jarkko