Re: [PATCH v11 00/16] Remove nested TPM operations

From: Alexander Steffen <Alexander.Steffen@infineon.com>
To: Stefan Berger <stefanb@linux.ibm.com>,
	Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: <linux-integrity@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<linux-security-module@vger.kernel.org>,
	Peter Huewe <PeterHuewe@gmx.de>, Jason Gunthorpe <jgg@ziepe.ca>,
	Tomas Winkler <tomas.winkler@intel.com>,
	Tadeusz Struk <tadeusz.struk@intel.com>,
	Stefan Berger <stefanb@linux.vnet.ibm.com>,
	Nayna Jain <nayna@linux.ibm.com>
Subject: Re: [PATCH v11 00/16] Remove nested TPM operations
Date: Fri, 8 Feb 2019 14:28:50 +0100	[thread overview]
Message-ID: <515b6c56-59e9-468d-35e0-3ae183bcea8c@infineon.com> (raw)
In-Reply-To: <9cd734ad-ea9d-77f7-b657-3f0910a9d92f@linux.ibm.com>

On 08.02.2019 03:14, Stefan Berger wrote:
> On 2/7/19 8:51 PM, Stefan Berger wrote:
>> On 2/7/19 7:33 PM, Jarkko Sakkinen wrote:
>>> On Thu, Feb 07, 2019 at 06:29:43PM -0500, Stefan Berger wrote:
>>>> On 2/7/19 4:29 PM, Jarkko Sakkinen wrote:
>>
>>
>>>
>>>> diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
>>>> index e74c5b7b64bf..52afe20cc8a1 100644
>>>> --- a/drivers/char/tpm/tpm2-cmd.c
>>>> +++ b/drivers/char/tpm/tpm2-cmd.c
>>>> @@ -799,7 +799,9 @@ int tpm2_probe(struct tpm_chip *chip)
>>>>       tpm_buf_append_u32(&buf, TPM2_CAP_TPM_PROPERTIES);
>>>>       tpm_buf_append_u32(&buf, TPM_PT_TOTAL_COMMANDS);
>>>>       tpm_buf_append_u32(&buf, 1);
>>>> +    tpm_chip_start(chip);
>>>>       rc = tpm_transmit_cmd(chip, &buf, 0, NULL);
>>>> +    tpm_chip_stop(chip);
>>> Thanks Stefan! I added call to tpm_tis_core as tpm2-cmd.c is to be kept
>>> out of chip management common case being that you call 
>>> tpm_try_get_ops(),
>>> do 1-N TPM commands and release with tpm_put_ops(). These functions take
>>> care starting and stopping the chip.
>>>
>>> I fixed the 2nd issue in the master.
>>
>> You also need to export the tpm_chip_start/stop symbols.
>>
>>
>> Master now seems to (still) have a problem when rmmod'ing:
>>
>> A TPM error (325) occurred stopping the TPM. This happens at the same 
>> patch where I had to add the tpm_chip_start/stop above.
>>
>>
> 
> Here's my current overall patch against your master. I suppose the other 
> tpm2_shutdown() for power management doesn't need the chip start ?
> 
> diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
> index 9865776ee2cd..f7147706a9c3 100644
> --- a/drivers/char/tpm/tpm-chip.c
> +++ b/drivers/char/tpm/tpm-chip.c
> @@ -115,6 +115,7 @@ int tpm_chip_start(struct tpm_chip *chip)
> 
>       return 0;
>   }
> +EXPORT_SYMBOL_GPL(tpm_chip_start);
> 
>   /**
>    * tpm_chip_stop() - power off the TPM
> @@ -131,7 +132,7 @@ void tpm_chip_stop(struct tpm_chip *chip)
>       if (chip->ops->clk_enable)
>           chip->ops->clk_enable(chip, false);
>   }
> -
> +EXPORT_SYMBOL_GPL(tpm_chip_stop);
> 
>   /**
>    * tpm_try_get_ops() - Get a ref to the tpm_chip
> @@ -474,8 +475,11 @@ static void tpm_del_char_device(struct tpm_chip *chip)
> 
>       /* Make the driver uncallable. */
>       down_write(&chip->ops_sem);
> -    if (chip->flags & TPM_CHIP_FLAG_TPM2)
> +    if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> +        tpm_chip_start(chip, 0);
>           tpm2_shutdown(chip, TPM2_SU_CLEAR);
> +        tpm_chip_stop(chip, 0);
> +    }
>       chip->ops = NULL;
>       up_write(&chip->ops_sem);
>   }
> diff --git a/drivers/char/tpm/tpm-interface.c 
> b/drivers/char/tpm/tpm-interface.c
> index 02e8cffd1163..fcd845ad8c3c 100644
> --- a/drivers/char/tpm/tpm-interface.c
> +++ b/drivers/char/tpm/tpm-interface.c
> @@ -124,6 +124,8 @@ static ssize_t tpm_try_transmit(struct tpm_chip 
> *chip, void *buf, size_t bufsiz)
>           dev_err(&chip->dev, "tpm_transmit: tpm_recv: error %d\n", rc);
>       } else if (len < TPM_HEADER_SIZE || len != 
> be32_to_cpu(header->length))
>           rc = -EFAULT;
> +    else
> +        rc = 0;
> 
>       return rc ? rc : len;
>   }

Applying those changes fixes all the issues I saw, thanks. I'll retest 
Jarkko's tree without custom patches, once you've agreed on the rc question.

Alexander