Re: [tpmdd-devel] [PATCH v9 8/8] tpm: TPM 2.0 FIFO Interface

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

On 12/05/2014 10:01 AM, Peter Huewe wrote:
>>> Am Donnerstag, 4. Dezember 2014, 06:55:18 schrieb Jarkko Sakkinen:
>>>> From: Will Arthur <will.c.arthur@intel.com>
>>>>
>>>> Detect TPM 2.0 by using the extended STS (STS3) register. For TPM 2.0,
>>>> instead of calling tpm_get_timeouts(), assign duration and timeout
>>>> values defined in the TPM 2.0 PTP specification.
>>>>
>>>> Signed-off-by: Will Arthur <will.c.arthur@intel.com>
>>>> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>>>> + sts3 = ioread8(chip->vendor.iobase + TPM_STS3(1));
>>>> + if ((sts3 & TPM_STS3_TPM2_FAM) == TPM_STS3_TPM2_FAM)
>>>> + chip->flags = TPM_CHIP_FLAG_TPM2;
>>>> +
>>>>
>>> When loading tpm_tis force=1 with my tpm1.2 chip on a machine without bios
>>> integration, it fets detected as a TPM2.0 chip :/
>>>
>>> sudo rmmod tpm_tis
>>> # modprobe tpm_tis force=1
>>> modprobe: ERROR: could not insert 'tpm_tis': No such device
>>> # dmesg
>>> [ 263.903828] tpm_tis tpm_tis: 2.0 TPM (device-id 0xB, rev-id 16)
>>> [ 263.948049] tpm_tis tpm_tis: A TPM error (10) occurred continue selftest
>>> [ 263.948120] tpm_tis tpm_tis: TPM self test failed
>>>
>>>
>>> sts3 is reported as 0xff from my TPM1.2
>>>
>>
>> Hmm,
>> my TPM2.0 chip also reports sts3 as 0xff (when loading with force=1 on a
>> machine without bios integration)
>>
>> [ 307.095344] sts3 ff
>> [ 307.095366] tpm_tis tpm_tis: 2.0 TPM (device-id 0x1A, rev-id 16)
>> [ 307.140047] tpm_tis tpm_tis: A TPM error (256) occurred continue selftest
>> [ 307.140056] tpm_tis tpm_tis: TPM self test failed
>
> You are reading "sts3" - before requesting the locality and thus it returns 0xff for a TPM20 chip as well.
> --> You have to have an active locality first.
>
>
> For a TPM2.0 0xFF is not a valid value (if active locality is set), since reading commandCancel and resetEstablishment bit always return 0 on reads (according to spec).
>
> --> 0xFF should be treated as a TPM1.2 (older tpms with TIS 1.2)
> --> 0x04 should be treated as TPM 2.0
> --> 0x08 should be treated as TPM1.2 (newer tpms with TIS1.3 enhanced)

> + sts3 = ioread8(chip->vendor.iobase + TPM_STS3(1));
> + if ((sts3 & TPM_STS3_TPM2_FAM) == TPM_STS3_TPM2_FAM)
> + chip->flags = TPM_CHIP_FLAG_TPM2;

#define TPM_STS3_TPM2_FAM_MASK = 0x0c

then:

if ((sts3 & TPM_STS3_TPM2_FAM_MASK) == TPM_STS3_TPM2_FAM) ...

[see my previous review on this]

    Stefan






>
>
>
> Thanks,
> Peter
>
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