Re: [PATCH] tpm: Detach page allocation from tpm_buf

[Jarkko Sakkinen]

On Thu, Sep 26, 2019 at 03:46:35PM +0300, Jarkko Sakkinen wrote:
> On Wed, Sep 25, 2019 at 04:48:41PM +0300, Jarkko Sakkinen wrote:
> > -		tpm_buf_reset(&buf, TPM2_ST_NO_SESSIONS, TPM2_CC_GET_RANDOM);
> > +		tpm_buf_reset(&buf, data_ptr, PAGE_SIZE,
> > +			      TPM2_ST_NO_SESSIONS, TPM2_CC_PCR_EXTEND);
> 
> Oops.

Maybe we could use random as the probe for TPM version since we anyway
send a TPM command as a probe for TPM version:

1. Try TPM2 get random.
2. If fail, try TPM1 get random.
3. Output random number to klog.

Something like 8 bytes would be sufficient. This would make sure that
no new change breaks tpm_get_random() and also this would give some
feedback that TPM is at least somewhat working.

/Jarkko