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

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Message-Id: <9cd734ad-ea9d-77f7-b657-3f0910a9d92f@linux.ibm.com>
Date:   Thu, 7 Feb 2019 21:14:54 -0500
From:   Stefan Berger <stefanb@...ux.ibm.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     Alexander Steffen <Alexander.Steffen@...ineon.com>,
        linux-integrity@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        Peter Huewe <PeterHuewe@....de>,
        Jason Gunthorpe <jgg@...pe.ca>,
        Tomas Winkler <tomas.winkler@...el.com>,
        Tadeusz Struk <tadeusz.struk@...el.com>,
        Stefan Berger <stefanb@...ux.vnet.ibm.com>,
        Nayna Jain <nayna@...ux.ibm.com>
Subject: Re: [PATCH v11 00/16] Remove nested TPM operations

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;
  }




>
>
>>
>>   /Jarkko
>>
>