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authorSasha Levin <sashal@kernel.org>2019-07-05 16:47:46 -0400
committerJarkko Sakkinen <jarkko.sakkinen@linux.intel.com>2019-09-02 17:08:35 +0300
commite8bd417aab0c72bfb54465596b16085702ba0405 (patch)
tree5f2e3d1f19d56c9675acb2f61ad3a6ba5ce0268a
parent09e574831b277a3f77d78ceadd08a3859a84fdb3 (diff)
downloadlinux-e8bd417aab0c72bfb54465596b16085702ba0405.tar.bz2
tpm/tpm_ftpm_tee: Document fTPM TEE driver
Documentation briefly the new fTPM driver running inside TEE. Signed-off-by: Sasha Levin <sashal@kernel.org> Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
-rw-r--r--Documentation/security/tpm/index.rst1
-rw-r--r--Documentation/security/tpm/tpm_ftpm_tee.rst27
2 files changed, 28 insertions, 0 deletions
diff --git a/Documentation/security/tpm/index.rst b/Documentation/security/tpm/index.rst
index 3296533e54cf..487852fda33e 100644
--- a/Documentation/security/tpm/index.rst
+++ b/Documentation/security/tpm/index.rst
@@ -6,3 +6,4 @@ Trusted Platform Module documentation
tpm_vtpm_proxy
xen-tpmfront
+ tpm_ftpm_tee
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.