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SubjectRe: [tpmdd-devel] [PATCH RFC 2/2] tpm: refactor tpm2_get_tpm_pt to tpm2_getcap_cmd
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On 11/15/2016 05:18 AM, Jarkko Sakkinen wrote:
> On Fri, Nov 11, 2016 at 04:02:43PM -0800, Jarkko Sakkinen wrote:
>> On Fri, Nov 11, 2016 at 09:51:45AM +0530, Nayna wrote:
>>>
>>>
>>> On 10/09/2016 03:44 PM, Jarkko Sakkinen wrote:
>>>> Refactored tpm2_get_tpm_pt to tpm2_getcap_cmd, which means that it also
>>>> takes capability ID as input. This is required to access
>>>> TPM_CAP_HANDLES, which contains metadata needed for swapping transient
>>>> data.
>>>>
>>>> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>>>> ---
>>>> drivers/char/tpm/tpm.h | 6 +++-
>>>> drivers/char/tpm/tpm2-cmd.c | 64 ++++++++++++++++++++---------------------
>>>> drivers/char/tpm/tpm_tis_core.c | 3 +-
>>>> 3 files changed, 38 insertions(+), 35 deletions(-)
>>>>
>>>> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
>>>> index 0fab6d5..8176f42 100644
>>>> --- a/drivers/char/tpm/tpm.h
>>>> +++ b/drivers/char/tpm/tpm.h
>>>> @@ -85,6 +85,10 @@ enum tpm2_capabilities {
>>>> TPM2_CAP_TPM_PROPERTIES = 6,
>>>> };
>>>>
>>>> +enum tpm2_properties {
>>>> + TPM2_PT_FAMILY_INDICATOR = 0x100,
>>>> +};
>>>> +
>>>> enum tpm2_startup_types {
>>>> TPM2_SU_CLEAR = 0x0000,
>>>> TPM2_SU_STATE = 0x0001,
>>>> @@ -485,7 +489,7 @@ int tpm2_seal_trusted(struct tpm_chip *chip,
>>>> int tpm2_unseal_trusted(struct tpm_chip *chip,
>>>> struct trusted_key_payload *payload,
>>>> struct trusted_key_options *options);
>>>> -ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id,
>>>> +ssize_t tpm2_getcap_cmd(struct tpm_chip *chip, u32 cap_id, u32 property_id,
>>>> u32 *value, const char *desc);
>>>>
>>>> int tpm2_auto_startup(struct tpm_chip *chip);
>>>> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
>>>> index 2900e18..fcf3d86 100644
>>>> --- a/drivers/char/tpm/tpm2-cmd.c
>>>> +++ b/drivers/char/tpm/tpm2-cmd.c
>>>> @@ -111,13 +111,13 @@ struct tpm2_pcr_extend_in {
>>>> u8 digest[TPM_DIGEST_SIZE];
>>>> } __packed;
>>>>
>>>> -struct tpm2_get_tpm_pt_in {
>>>> +struct tpm2_getcap_in {
>>>> __be32 cap_id;
>>>> __be32 property_id;
>>>> __be32 property_cnt;
>>>> } __packed;
>>>>
>>>> -struct tpm2_get_tpm_pt_out {
>>>> +struct tpm2_getcap_out {
>>>> u8 more_data;
>>>> __be32 subcap_id;
>>>> __be32 property_cnt;
>>>> @@ -140,8 +140,8 @@ union tpm2_cmd_params {
>>>> struct tpm2_pcr_read_in pcrread_in;
>>>> struct tpm2_pcr_read_out pcrread_out;
>>>> struct tpm2_pcr_extend_in pcrextend_in;
>>>> - struct tpm2_get_tpm_pt_in get_tpm_pt_in;
>>>> - struct tpm2_get_tpm_pt_out get_tpm_pt_out;
>>>> + struct tpm2_getcap_in getcap_in;
>>>> + struct tpm2_getcap_out getcap_out;
>>>> struct tpm2_get_random_in getrandom_in;
>>>> struct tpm2_get_random_out getrandom_out;
>>>> };
>>>> @@ -435,16 +435,6 @@ int tpm2_get_random(struct tpm_chip *chip, u8 *out, size_t max)
>>>> return total ? total : -EIO;
>>>> }
>>>>
>>>> -#define TPM2_GET_TPM_PT_IN_SIZE \
>>>> - (sizeof(struct tpm_input_header) + \
>>>> - sizeof(struct tpm2_get_tpm_pt_in))
>>>> -
>>>> -static const struct tpm_input_header tpm2_get_tpm_pt_header = {
>>>> - .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
>>>> - .length = cpu_to_be32(TPM2_GET_TPM_PT_IN_SIZE),
>>>> - .ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
>>>> -};
>>>> -
>>>> /**
>>>> * Append TPMS_AUTH_COMMAND to the buffer. The buffer must be allocated with
>>>> * tpm_buf_alloc().
>>>> @@ -750,35 +740,43 @@ out:
>>>> return rc;
>>>> }
>>>>
>>>> +#define TPM2_GETCAP_IN_SIZE \
>>>> + (sizeof(struct tpm_input_header) + sizeof(struct tpm2_getcap_in))
>>>> +
>>>> +static const struct tpm_input_header tpm2_getcap_header = {
>>>> + .tag = cpu_to_be16(TPM2_ST_NO_SESSIONS),
>>>> + .length = cpu_to_be32(TPM2_GETCAP_IN_SIZE),
>>>> + .ordinal = cpu_to_be32(TPM2_CC_GET_CAPABILITY)
>>>> +};
>>>> +
>>>> /**
>>>> - * tpm2_get_tpm_pt() - get value of a TPM_CAP_TPM_PROPERTIES type property
>>>> - * @chip: TPM chip to use.
>>>> - * @property_id: property ID.
>>>> - * @value: output variable.
>>>> + * tpm2_getcap_cmd() - execute a TPM2_GetCapability command
>>>> + * @chip: TPM chip to use
>>>> + * @cap_id: capability ID
>>>> + * @property_id: property ID
>>>> + * @value: value of the property
>>>> * @desc: passed to tpm_transmit_cmd()
>>>> *
>>>> - * 0 is returned when the operation is successful. If a negative number is
>>>> - * returned it remarks a POSIX error code. If a positive number is returned
>>>> - * it remarks a TPM error.
>>>> + * Return: same as with tpm_transmit_cmd
>>>> */
>>>> -ssize_t tpm2_get_tpm_pt(struct tpm_chip *chip, u32 property_id, u32 *value,
>>>> - const char *desc)
>>>> +ssize_t tpm2_getcap_cmd(struct tpm_chip *chip, u32 cap_id, u32 property_id,
>>>> + u32 *value, const char *desc)
>>>
>>> This function currently returns single value "u32 *value" as output data.
>>>
>>> Some calling function expect list of values from capabilities output.
>>> For eg., get_active_banks() use TPM_CAP_PCRS capability to retrieve list of
>>> active banks. And this capability returns array of pcr selections(which is a
>>> struct representing each active PCR bank)
>>>
>>> I was thinking, can we define output parameter as struct of cap_id and union
>>> of expected cap_data ?
>>
>> Unless you have major concerns about performance, which I think are not
>> relevant here, calling this in a loop is perfectly adequate and a lot of
>> simpler than having a generic version (with moreData handling and
>> everything).
>>
>> I would rather see uses of struct cap_t to shrink than to expand. The
>> same goes for other horrific unions that exist today in the driver.
>
> If you are fine with this patch (give Reviewed-by) I can apply this
> and add to my 4.10 pull request so that we have common baseline to
> develop both event log and the resource manager.
>
> This is a very low risk commit to take to 4.10 because it is only used
> for interrupt generation in the TIS driver at the moment.

Works for capabilities with more_data(yes) and single value properties.

Reviewed-by: Nayna Jain <nayna@linux.vnet.ibm.com>

Thanks & Regards,
- Nayna

>
> /Jarkko
>

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