On 6/25/19 1:13 PM, Sasha Levin wrote: > This patch adds basic documentation to describe the new fTPM driver. > > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> Acked-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Thanks. > --- > Documentation/security/tpm/index.rst | 1 + > Documentation/security/tpm/tpm_ftpm_tee.rst | 31 +++++++++++++++++++++ > 2 files changed, 32 insertions(+) > create mode 100644 Documentation/security/tpm/tpm_ftpm_tee.rst > > diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst > index af77a7bbb070..15783668644f 100644 > --- a/Documentation/security/tpm/index.rst > +++ b/Documentation/security/tpm/index.rst > @@ -4,4 +4,5 @@ Trusted Platform Module documentation > > .. toctree:: > > + tpm_ftpm_tee > tpm_vtpm_proxy > diff --git a/Documentation/security/tpm/tpm_ftpm_tee.rst b/Documentation/security/tpm/tpm_ftpm_tee.rst > new file mode 100644 > index 000000000000..48de0dcec0f6 > --- /dev/null > +++ b/Documentation/security/tpm/tpm_ftpm_tee.rst > @@ -0,0 +1,31 @@ > +============================================= > +Firmware TPM Driver > +============================================= > + > +| Authors: > +| Thirupathaiah Annapureddy <thiruan@xxxxxxxxxxxxx> > +| Sasha Levin <sashal@xxxxxxxxxx> > + > +This document describes the firmware Trusted Platform Module (fTPM) > +device driver. > + > +Introduction > +============ > + > +This driver is a shim for firmware implemented in ARM's TrustZone > +environment. The driver allows programs to interact with the TPM in the same > +way they would interact with a hardware TPM. > + > +Design > +====== > + > +The driver acts as a thin layer that passes commands to and from a TPM > +implemented in firmware. The driver itself doesn't contain much logic and is > +used more like a dumb pipe between firmware and kernel/userspace. > + > +The firmware itself is based on the following paper: > +https://www.microsoft.com/en-us/research/wp-content/uploads/2017/06/ftpm1.pdf > + > +When the driver is loaded it will expose ``/dev/tpmX`` character devices to > +userspace which will enable userspace to communicate with the firmware TPM > +through this device. > -- ~Randy
