Re: [PATCH v3 1/2] ftpm: firmware TPM running in TEE

[Sasha Levin]

On Wed, May 15, 2019 at 11:12:50AM +0300, Jarkko Sakkinen wrote:
> On Mon, Apr 15, 2019 at 11:56:35AM -0400, Sasha Levin wrote:
> > This patch adds support for a software-only implementation of a TPM
> > running in TEE.
> >
> > There is extensive documentation of the design here:
> > https://www.microsoft.com/en-us/research/publication/ftpm-software-implementation-tpm-chip/ .
> >
> > As well as reference code for the firmware available here:
> > https://github.com/Microsoft/ms-tpm-20-ref/tree/master/Samples/ARM32-FirmwareTPM
>
> The commit message should include at least a brief description what TEE
> is.

The whole TEE subsystem is already well documented in our kernel tree
(https://www.kernel.org/doc/Documentation/tee.txt) and beyond. I can add
a reference to the doc here, but I'd rather not add a bunch of TEE
related comments as you suggest later in your review.

The same way a PCI device driver doesn't describe what PCI is in it's
code, we shouldn't be doing the same for TEE here.

> > +
> > +#include <linux/of.h>
> > +#include <linux/of_platform.h>
> > +#include <linux/acpi.h>
> > +#include <linux/platform_device.h>
> > +#include <linux/tee_drv.h>
> > +#include <linux/uuid.h>
> > +#include <linux/tpm.h>
> > +
> > +#include "tpm.h"
> > +#include "tpm_ftpm_tee.h"
> > +
> > +#define DRIVER_NAME "ftpm-tee"
> > +
> > +/* TA_FTPM_UUID: BC50D971-D4C9-42C4-82CB-343FB7F37896 */
> > +static const uuid_t ftpm_ta_uuid =
> > +	UUID_INIT(0xBC50D971, 0xD4C9, 0x42C4,
> > +		  0x82, 0xCB, 0x34, 0x3F, 0xB7, 0xF3, 0x78, 0x96);
>
> Just wondering why prefixes are here in different order in the comment
> and code.

No prefixes, this is a completely randomly generated UUID.

I'll address the rest of your comments in the next ver.

--
Thanks,
Sasha