Re: tpm device not showing up in /dev anymore

[Laurent Bigonville <bigon-8fiUuRrzOP0dnm+yROfE0A@public.gmane.org>]

Le 23/10/17 à 15:45, Jerry Snitselaar a écrit :
> On Mon Oct 23 17, Jarkko Sakkinen wrote:
>> On Sat, Oct 21, 2017 at 10:53:55AM +0200, Laurent Bigonville wrote:
>>> Le 14/10/17 à 10:13, Jerry Snitselaar a écrit :
>>> > 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@infineon.com wrote:
>>> > > > > > > Le 29/08/17 à 18:35, Laurent Bigonville a écrit :
>>> > > > > > > > Le 29/08/17 à 18:00, Alexander.Steffen@infineon.com 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@redhat.com>
>>> > > > > > > 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@gmx.de>
>>> > > > > > >      Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
>>> > > > > > >      Cc: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
>>> > > > > > >      Cc: Marcel Selhorst <tpmdd@selhorst.net>
>>> > > > > > >      Signed-off-by: Jerry Snitselaar <jsnitsel@redhat.com>
>>> > > > > > >      Reviewed-by: Jarkko Sakkinen
>>> > > > <jarkko.sakkinen@linux.intel.com>
>>> > > > > > >      Tested-by: Jarkko Sakkinen 
>>> <jarkko.sakkinen@linux.intel.com>
>>> > > > > > >      Signed-off-by: Jarkko Sakkinen
>>> > > > <jarkko.sakkinen@linux.intel.com>
>>> > > > > > >
>>> > > > > > > :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;
>>> >     }
>>>
>>> Please find here the dmesg output of the patched kernel
>>
>> At least 0xff is corrupted value in senseful way. CPU fills the read
>> with ones for example for unaligned bus read. See table 19 in PC client
>> spec. This can happen when you do unaligned read for example.
>>
>> Maybe TPM is unreachable i.e. powered off. Bit busy with stuff ATM but
>> would probably make sense to compare that 0x81 to table 18 in the same
>> spec.
>>
>> /Jarkko
>
> 0x81 is saying the access register status is valid, and the locality
> is not active. That first bit means A Dynamic OS has not been previously
> established on the platform. Normally we would see 0xa1, which would
> mean valid register status, and the locality is active.

FTR, the ownership has been claimed using tpm-tools on linux, but I 
configured windows 10 (dual-boot) on the machine to do its magic to 
recognize the tpm chip by entering the owner password manually there, 
not sure if that matters.

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