Re: [tpmdd-devel] tpm device not showing up in /dev anymore

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On Wed Sep 06 17, Jarkko Sakkinen wrote:
On Fri, Sep 01, 2017 at 02:10:18PM +0200, Laurent Bigonville wrote:
Le 31/08/17 à 18:40, Jerry Snitselaar a écrit :
> On Thu Aug 31 17, Alexander.Steffen@xxxxxxxxxxxx wrote:
> > > Le 29/08/17 à 18:35, Laurent Bigonville a écrit :
> > > > Le 29/08/17 à 18:00, Alexander.Steffen@xxxxxxxxxxxx a écrit :
> > > >>> An idea how to troubleshoot this?
> > > >> Can you run git bisect on the changes between 4.11 and 4.12, so that
> > > >> we find the offending commit? It is probably sufficient to limit the
> > > >> search to commits that touch something in drivers/char/tpm.
> > > >
> > > > I'll try and keep you posted.
> > >
> > > OK I've been able to bisect the problem and the bad commit is:
> > >
> > > e6aef069b6e97790cb127d5eeb86ae9ff0b7b0e3 is the first bad commit
> > > commit e6aef069b6e97790cb127d5eeb86ae9ff0b7b0e3
> > > Author: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
> > > Date:   Mon Mar 27 08:46:04 2017 -0700
> > >
> > >      tpm_tis: convert to using locality callbacks
> > >
> > >      This patch converts tpm_tis to use of the new tpm class ops
> > >      request_locality, and relinquish_locality.
> > >
> > >      With the move to using the callbacks, release_locality is
> > > changed so
> > >      that we now release the locality even if there is no
> > > request pending.
> > >
> > >      This required some changes to the tpm_tis_core_init code path to
> > >      make sure locality is requested when needed:
> > >
> > >        - tpm2_probe code path will end up calling
> > > request/release through
> > >          callbacks, so request_locality prior to tpm2_probe not needed.
> > >
> > >        - probe_itpm makes calls to tpm_tis_send_data which no
> > > longer calls
> > >          request_locality, so add request_locality prior to
> > > tpm_tis_send_data
> > >          calls. Also drop release_locality call in middleof
> > > probe_itpm, and
> > >          keep locality until release_locality called at end of
> > > probe_itpm.
> > >
> > >      Cc: Peter Huewe <peterhuewe@xxxxxx>
> > >      Cc: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > >      Cc: Jason Gunthorpe <jgunthorpe@xxxxxxxxxxxxxxxxxxxx>
> > >      Cc: Marcel Selhorst <tpmdd@xxxxxxxxxxxx>
> > >      Signed-off-by: Jerry Snitselaar <jsnitsel@xxxxxxxxxx>
> > >      Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > >      Tested-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > >      Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
> > >
> > > :040000 040000 70234365da69959d47076ebb40c8d17f520c3e44
> > > 72f21b446e45ea1003de75902b0553deb99157fd M    drivers
> > >
> >
> > I've looked again at the code in question, but could not find
> > anything that is obviously wrong there. Locality is now
> > requested/released at slightly different points in the process than
> > before, but that's it. It does not seem to cause problems with the
> > majority of TPMs, since you are the first to report any, so maybe it
> > is a quirk that only affects this device.
> >
> > Perhaps Jerry can help, since this is his change?
> >
> > Alexander
>
> Getting some caffeine in me, and starting to take a look. Adding
> Jarkko as well since this might involve the general locality changes.
>
> Laurent, if I send you a patch with some debugging code added, would
> you be able to run it on that system? I wasn't running into issues
> on the system I had with a 1.2 device, but I no longer have access
> to it. I'll see if I can find one in our labs and reproduce it there.

Yes I should be able to do that

Any findings?

/Jarkko

Okay, finally getting back to this. Looking at the code it isn't clear to me
why the change is causing this. So while I stare at this some more Laurent
could you reproduce it with this patch so I can see what the status and
access registers look like? Does anyone else on here happen to have a Sinosun
tpm device? The systems I have access to with TPM1.2 devices don't have this
issue.

--8<--

diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
index fdde971bc810..7d60a7e4b50a 100644
--- a/drivers/char/tpm/tpm_tis_core.c
+++ b/drivers/char/tpm/tpm_tis_core.c
@@ -258,6 +258,7 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
	int rc, status, burstcnt;
	size_t count = 0;
	bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
+	u8 access;

	status = tpm_tis_status(chip);
	if ((status & TPM_STS_COMMAND_READY) == 0) {
@@ -292,6 +293,11 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
		}
		status = tpm_tis_status(chip);
		if (!itpm && (status & TPM_STS_DATA_EXPECT) == 0) {
+			rc = tpm_tis_read8(priv, TPM_ACCESS(priv->locality), &access);
+			if (rc < 0)
+				dev_info(&chip->dev, "TPM_STS_DATA_EXPECT == 0: read failure TPM_ACCESS(%d)\n", priv->locality);
+			else
+				dev_info(&chip->dev, "TPM_STS_DATA_EXPECT == 0: locality: %d status: %x access: %x\n", priv->locality, status, access);
			rc = -EIO;
			goto out_err;
		}
@@ -309,6 +315,11 @@ static int tpm_tis_send_data(struct tpm_chip *chip, const u8 *buf, size_t len)
	}
	status = tpm_tis_status(chip);
	if (!itpm && (status & TPM_STS_DATA_EXPECT) != 0) {
+		rc = tpm_tis_read8(priv, TPM_ACCESS(priv->locality), &access);
+		if (rc < 0)
+			dev_info(&chip->dev, "TPM_STS_DATA_EXPECT != 0: read failure TPM_ACCESS(%d)\n", priv->locality);
+		else
+			dev_info(&chip->dev, "TPM_STS_DATA_EXPECT != 0: locality: %d status: %x access: %x\n", priv->locality, status, access);
		rc = -EIO;
		goto out_err;
	}
--
2.15.0.rc0





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