Re: [PATCH REVIEW 2/2] tpm_tis: override durations for STM tpm with firmware 1.2.8.28

[Jerry Snitselaar <jsnitsel@redhat.com>]

On Thu Jan 03 19, Jarkko Sakkinen wrote:
>On Fri, Dec 14, 2018 at 01:21:15PM +0000, Alexey Klimov wrote:
>> There was revealed a bug in the STM TPM chipset used in Dell R415s.
>> Bug is observed so far only on chipset firmware 1.2.8.28
>> (1.2 TPM, device-id 0x0, rev-id 78). After some number of
>> operations chipset hangs and stays in inconsistent state:
>>
>> tpm_tis 00:09: Operation Timed out
>> tpm_tis 00:09: tpm_transmit: tpm_send: error -5
>>
>> Durations returned by the chip are the same like on other
>> firmware revisions but apparently with specifically 1.2.8.28 fw
>> durations should be reset to 2 minutes to enable tpm chip work
>> properly. No working way of updating firmware was found.
>>
>> This patch adds implementation of ->update_durations method
>> that matches only STM devices with specific firmware version.
>>
>> Cc: Jerry Snitselaar <jsnitsel@redhat.com>
>> Signed-off-by: Alexey Klimov <aklimov@redhat.com>
>> ---
>>  drivers/char/tpm/tpm_tis_core.c | 90 +++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 90 insertions(+)
>>
>> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
>> index d2345d9fd7b5..e0bdca647460 100644
>> --- a/drivers/char/tpm/tpm_tis_core.c
>> +++ b/drivers/char/tpm/tpm_tis_core.c
>> @@ -514,6 +514,95 @@ static int tpm_tis_send(struct tpm_chip *chip, u8 *buf, size_t len)
>>  	return rc;
>>  }
>>
>> +struct tis_vendor_durations_override {
>> +	u32 did_vid;
>> +	struct tpm_version_t tpm_version;
>> +	unsigned long durs[3];
>
>I would rather have just "unsigned long durations[3];".
>
>> +};
>> +
>> +static
>> +const struct tis_vendor_durations_override vendor_dur_overrides[] = {
>> +	/* STMicroelectronics 0x104a */
>> +	{ 0x0000104A,
>> +	{ 1, 2, 8, 28 },
>> +	{ (2 * 60 * HZ), (2 * 60 * HZ), (2 * 60 * HZ) } },
>> +};
>> +
>> +static bool tpm_tis_update_durations(struct tpm_chip *chip,
>> +					unsigned long *duration_cap)
>> +{
>> +	struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
>> +	u32 did_vid;
>> +	int i, rc;
>> +	cap_t cap;
>> +
>> +	if (chip->ops->clk_enable != NULL)
>> +		chip->ops->clk_enable(chip, true);
>> +
>> +	rc = tpm_tis_read32(priv, TPM_DID_VID(0), &did_vid);
>> +	if (rc < 0)
>> +		goto out;
>> +
>> +	for (i = 0; i != ARRAY_SIZE(vendor_dur_overrides); i++) {
>> +		if (vendor_dur_overrides[i].did_vid != did_vid)
>> +			continue;
>> +
>> +		/* Try to get a TPM version 1.2 TPM_CAP_VERSION_INFO */
>> +		rc = tpm_getcap(chip, TPM_CAP_VERSION_1_2, &cap,
>> +			"attempting to determine the 1.2 version",
>> +			sizeof(cap.tpm_version_1_2));
>
>Not properly aligned.
>
>> +		if (!rc) {
>> +			if ((cap.tpm_version_1_2.Major ==
>> +				vendor_dur_overrides[i].tpm_version.Major) &&
>> +				(cap.tpm_version_1_2.Minor ==
>> +				vendor_dur_overrides[i].tpm_version.Minor) &&
>> +				(cap.tpm_version_1_2.revMajor ==
>> +				vendor_dur_overrides[i].tpm_version.revMajor) &&
>> +				(cap.tpm_version_1_2.revMinor ==
>> +				vendor_dur_overrides[i].tpm_version.revMinor)) {
>
>Same.
>
>> +
>> +				memcpy(duration_cap,
>> +					vendor_dur_overrides[i].durs,
>> +					sizeof(vendor_dur_overrides[i].durs));
>
>Same.
>
>> +				rc = true;
>> +				goto out;
>> +			}
>> +		} else {
>> +			rc = tpm_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
>> +				"attempting to determine the 1.1 version",
>> +				sizeof(cap.tpm_version));
>
>Same.
>
>> +			if (rc) {
>> +				rc = false;
>> +				goto out;
>> +			}
>> +			if ((cap.tpm_version.Major ==
>> +				vendor_dur_overrides[i].tpm_version.Major) &&
>> +				(cap.tpm_version.Minor ==
>> +				vendor_dur_overrides[i].tpm_version.Minor) &&
>> +				(cap.tpm_version.revMajor ==
>> +				vendor_dur_overrides[i].tpm_version.revMajor) &&
>> +				(cap.tpm_version.revMinor ==
>> +				vendor_dur_overrides[i].tpm_version.revMinor)) {
>
>Same.
>
>> +
>> +				memcpy(duration_cap,
>> +					vendor_dur_overrides[i].durs,
>> +					sizeof(vendor_dur_overrides[i].durs));
>
>Same.
>
>> +				rc = true;
>> +				goto out;
>> +			}
>> +		}
>> +	}
>> +
>> +	rc = false;
>
>Shoud return proper rc instead of bool.
>

Alexey was following the example of tpm_tis_update_timeouts() which
returns true if the timeouts were updated, and otherwise returns
false. The bool here makes sense to me, but what rc would you suggest
in this case?

Regards,
Jerry

>> +
>> +out:
>> +	if (chip->ops->clk_enable != NULL)
>> +		chip->ops->clk_enable(chip, false);
>> +
>> +	return rc;
>> +}
>> +
>> +
>>  struct tis_vendor_timeout_override {
>>  	u32 did_vid;
>>  	unsigned long timeout_us[4];
>> @@ -847,6 +936,7 @@ static const struct tpm_class_ops tpm_tis = {
>>  	.send = tpm_tis_send,
>>  	.cancel = tpm_tis_ready,
>>  	.update_timeouts = tpm_tis_update_timeouts,
>> +	.update_durations = tpm_tis_update_durations,
>>  	.req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
>>  	.req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
>>  	.req_canceled = tpm_tis_req_canceled,
>> --
>> 2.14.4
>>
>
>/Jarkko