Re: Getting weird TPM error after rebasing my tree to security/next-general

[Jason Gunthorpe <jgg@ziepe.ca>]

On Tue, Jan 22, 2019 at 03:02:18AM +0200, Jarkko Sakkinen wrote:
> On Sun, Jan 20, 2019 at 06:04:13PM +0200, Jarkko Sakkinen wrote:
> > On Fri, Jan 18, 2019 at 02:09:18PM -0800, James Bottomley wrote:
> > > On Fri, 2019-01-18 at 16:25 +0200, Jarkko Sakkinen wrote:
> > > > I get this on a Geminilake NUC after rebasing my maintainer trees:
> > > > 
> > > > tpm tpm0: A TPM error (-1) occurred attempting the self test
> > > > 
> > > > I checked the latest commit ID from drivers/char/tpm to make sure
> > > > that I did not put anything broken to my last PR [1]. It works
> > > > without issues.
> > > > 
> > > > In addition [2] gives me an empty diff.
> > > > 
> > > > Something outside of the TPM driver must have happened that breaks
> > > > the driver. Any ideas?
> > > > 
> > > > [1] commit 9488585b21bef0df1217e510c7134905d1d376a7
> > > > [2] git diff 9488585b21bef0df1217e510c7134905d1d376a7 master
> > > > drivers/char/tpm/
> > > 
> > > I'm afraid you're going to have to bisect to find the offending in-
> > > kernel commit, which is going to be painful since it seems to depend on
> > > physical hardware.  My first instinct is that we're getting a zero
> > > length read somewhere, but I still can't see anything in the merge
> > > window that would cause that behaviour.
> > 
> > Yeah, I've started to bisect it (still 9 rounds to go).
> 
> Fails on commit 170d13ca3a2fdaaa0283399247631b76b441cca2. Still works on
> preceding commit a959dc88f9c8900296ccf13e2f3e1cbc555a8917.

This changes the IO access pattern in memcpy_to/fromio.. Presumably
CRB HW doesn't like the new 4 byte move? Swap each one in crb to
memcpy to confirm..

If the HW requires particular access patterns you can't use
memcpy_to/fromio

Jason