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

[Alexander Steffen]

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).

With all that fixed in my environment, my tests now pass successfully.

Alexander