[v8,2/2] fTPM: add documentation for ftpm driver

Commit Message

Sasha Levin July 5, 2019, 8:47 p.m. UTC

This patch adds basic documentation to describe the new fTPM driver.

Signed-off-by: Sasha Levin <[e-mail]>
---
 Documentation/security/tpm/index.rst        |  1 +
 Documentation/security/tpm/tpm_ftpm_tee.rst | 27 +++++++++++++++++++++
 2 files changed, 28 insertions(+)
 create mode 100644 Documentation/security/tpm/tpm_ftpm_tee.rst

Comments

Jarkko Sakkinen July 11, 2019, 8:05 p.m. UTC | #1

On Fri, Jul 05, 2019 at 04:47:46PM -0400, Sasha Levin wrote:
> This patch adds basic documentation to describe the new fTPM driver.
> 
> Signed-off-by: Sasha Levin <[e-mail]>

Reviewed-by: Jarkko Sakkinen <[e-mail]>

/Jarkko

Patch

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..8c2bae16e3d9
--- /dev/null
+++ b/Documentation/security/tpm/tpm_ftpm_tee.rst
@@ -0,0 +1,27 @@ 
+=============================================
+Firmware TPM Driver
+=============================================
+
+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.