Documentation/ABI/stable/sysfs-class-tpm

Source file repositories/reference/linux-study-clean/Documentation/ABI/stable/sysfs-class-tpm

File Facts

System
Linux kernel
Corpus path
Documentation/ABI/stable/sysfs-class-tpm
Extension
[no extension]
Size
7786 bytes
Lines
211
Domain
Support Tooling And Documentation
Bucket
Documentation
Inferred role
Support Tooling And Documentation: Documentation
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

What:		/sys/class/tpm/tpmX/device/
Date:		April 2005
KernelVersion:	2.6.12
Contact:	linux-integrity@vger.kernel.org
Description:	The device/ directory under a specific TPM instance exposes
		the properties of that TPM chip


What:		/sys/class/tpm/tpmX/device/active
Date:		April 2006
KernelVersion:	2.6.17
Contact:	linux-integrity@vger.kernel.org
Description:	The "active" property prints a '1' if the TPM chip is accepting
		commands. An inactive TPM chip still contains all the state of
		an active chip (Storage Root Key, NVRAM, etc), and can be
		visible to the OS, but will only accept a restricted set of
		commands. See the TPM Main Specification part 2, Structures,
		section 17 for more information on which commands are
		available.

What:		/sys/class/tpm/tpmX/device/cancel
Date:		June 2005
KernelVersion:	2.6.13
Contact:	linux-integrity@vger.kernel.org
Description:	The "cancel" property allows you to cancel the currently
		pending TPM command. Writing any value to cancel will call the
		TPM vendor specific cancel operation.

What:		/sys/class/tpm/tpmX/device/caps
Date:		April 2005
KernelVersion:	2.6.12
Contact:	linux-integrity@vger.kernel.org
Description:	The "caps" property contains TPM manufacturer and version info.

		Example output::

		  Manufacturer: 0x53544d20
		  TCG version: 1.2
		  Firmware version: 8.16

		Manufacturer is a hex dump of the 4 byte manufacturer info
		space in a TPM. TCG version shows the TCG TPM spec level that
		the chip supports. Firmware version is that of the chip and
		is manufacturer specific.

What:		/sys/class/tpm/tpmX/device/durations
Date:		March 2011
KernelVersion:	3.1
Contact:	linux-integrity@vger.kernel.org
Description:	The "durations" property shows the 3 vendor-specific values
		used to wait for a short, medium and long TPM command. All
		TPM commands are categorized as short, medium or long in
		execution time, so that the driver doesn't have to wait
		any longer than necessary before starting to poll for a
		result.

		Example output::

		  3015000 4508000 180995000 [original]

		Here the short, medium and long durations are displayed in
		usecs. "[original]" indicates that the values are displayed
		unmodified from when they were queried from the chip.
		Durations can be modified in the case where a buggy chip
		reports them in msec instead of usec and they need to be
		scaled to be displayed in usecs. In this case "[adjusted]"
		will be displayed in place of "[original]".

What:		/sys/class/tpm/tpmX/device/enabled
Date:		April 2006

Annotation

Implementation Notes