tpm: add documentation for sysfs interfaces (feab398e) · Commits · e / devices / android_kernel_fairphone_FP3

Documentation/ABI/stable/sysfs-class-tpm

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		What: /sys/class/misc/tpmX/device/
		Date: April 2005
		KernelVersion: 2.6.12
		Contact: tpmdd-devel@lists.sf.net
		Description: The device/ directory under a specific TPM instance exposes
		the properties of that TPM chip


		What: /sys/class/misc/tpmX/device/active
		Date: April 2006
		KernelVersion: 2.6.17
		Contact: tpmdd-devel@lists.sf.net
		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/misc/tpmX/device/cancel
		Date: June 2005
		KernelVersion: 2.6.13
		Contact: tpmdd-devel@lists.sf.net
		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/misc/tpmX/device/caps
		Date: April 2005
		KernelVersion: 2.6.12
		Contact: tpmdd-devel@lists.sf.net
		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/misc/tpmX/device/durations
		Date: March 2011
		KernelVersion: 3.1
		Contact: tpmdd-devel@lists.sf.net
		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/misc/tpmX/device/enabled
		Date: April 2006
		KernelVersion: 2.6.17
		Contact: tpmdd-devel@lists.sf.net
		Description: The "enabled" property prints a '1' if the TPM chip is enabled,
		meaning that it should be visible to the OS. This property
		may be visible but produce a '0' after some operation that
		disables the TPM.

		What: /sys/class/misc/tpmX/device/owned
		Date: April 2006
		KernelVersion: 2.6.17
		Contact: tpmdd-devel@lists.sf.net
		Description: The "owned" property produces a '1' if the TPM_TakeOwnership
		ordinal has been executed successfully in the chip. A '0'
		indicates that ownership hasn't been taken.

		What: /sys/class/misc/tpmX/device/pcrs
		Date: April 2005
		KernelVersion: 2.6.12
		Contact: tpmdd-devel@lists.sf.net
		Description: The "pcrs" property will dump the current value of all Platform
		Configuration Registers in the TPM. Note that since these
		values may be constantly changing, the output is only valid
		for a snapshot in time.

		Example output:

		PCR-00: 3A 3F 78 0F 11 A4 B4 99 69 FC AA 80 CD 6E 39 57 C3 3B 22 75
		PCR-01: 3A 3F 78 0F 11 A4 B4 99 69 FC AA 80 CD 6E 39 57 C3 3B 22 75
		PCR-02: 3A 3F 78 0F 11 A4 B4 99 69 FC AA 80 CD 6E 39 57 C3 3B 22 75
		PCR-03: 3A 3F 78 0F 11 A4 B4 99 69 FC AA 80 CD 6E 39 57 C3 3B 22 75
		PCR-04: 3A 3F 78 0F 11 A4 B4 99 69 FC AA 80 CD 6E 39 57 C3 3B 22 75
		...

		The number of PCRs and hex bytes needed to represent a PCR
		value will vary depending on TPM chip version. For TPM 1.1 and
		1.2 chips, PCRs represent SHA-1 hashes, which are 20 bytes
		long. Use the "caps" property to determine TPM version.

		What: /sys/class/misc/tpmX/device/pubek
		Date: April 2005
		KernelVersion: 2.6.12
		Contact: tpmdd-devel@lists.sf.net
		Description: The "pubek" property will return the TPM's public endorsement
		key if possible. If the TPM has had ownership established and
		is version 1.2, the pubek will not be available without the
		owner's authorization. Since the TPM driver doesn't store any
		secrets, it can't authorize its own request for the pubek,
		making it unaccessible. The public endorsement key is gener-
		ated at TPM menufacture time and exists for the life of the
		chip.

		Example output:

		Algorithm: 00 00 00 01
		Encscheme: 00 03
		Sigscheme: 00 01
		Parameters: 00 00 08 00 00 00 00 02 00 00 00 00
		Modulus length: 256
		Modulus:
		B4 76 41 82 C9 20 2C 10 18 40 BC 8B E5 44 4C 6C
		3A B2 92 0C A4 9B 2A 83 EB 5C 12 85 04 48 A0 B6
		1E E4 81 84 CE B2 F2 45 1C F0 85 99 61 02 4D EB
		86 C4 F7 F3 29 60 52 93 6B B2 E5 AB 8B A9 09 E3
		D7 0E 7D CA 41 BF 43 07 65 86 3C 8C 13 7A D0 8B
		82 5E 96 0B F8 1F 5F 34 06 DA A2 52 C1 A9 D5 26
		0F F4 04 4B D9 3F 2D F2 AC 2F 74 64 1F 8B CD 3E
		1E 30 38 6C 70 63 69 AB E2 50 DF 49 05 2E E1 8D
		6F 78 44 DA 57 43 69 EE 76 6C 38 8A E9 8E A3 F0
		A7 1F 3C A8 D0 12 15 3E CA 0E BD FA 24 CD 33 C6
		47 AE A4 18 83 8E 22 39 75 93 86 E6 FD 66 48 B6
		10 AD 94 14 65 F9 6A 17 78 BD 16 53 84 30 BF 70
		E0 DC 65 FD 3C C6 B0 1E BF B9 C1 B5 6C EF B1 3A
		F8 28 05 83 62 26 11 DC B4 6B 5A 97 FF 32 26 B6
		F7 02 71 CF 15 AE 16 DD D1 C1 8E A8 CF 9B 50 7B
		C3 91 FF 44 1E CF 7C 39 FE 17 77 21 20 BD CE 9B

		Possible values:

		Algorithm: TPM_ALG_RSA (1)
		Encscheme: TPM_ES_RSAESPKCSv15 (2)
		TPM_ES_RSAESOAEP_SHA1_MGF1 (3)
		Sigscheme: TPM_SS_NONE (1)
		Parameters, a byte string of 3 u32 values:
		Key Length (bits): 00 00 08 00 (2048)
		Num primes: 00 00 00 02 (2)
		Exponent Size: 00 00 00 00 (0 means the
		default exp)
		Modulus Length: 256 (bytes)
		Modulus: The 256 byte Endorsement Key modulus

		What: /sys/class/misc/tpmX/device/temp_deactivated
		Date: April 2006
		KernelVersion: 2.6.17
		Contact: tpmdd-devel@lists.sf.net
		Description: The "temp_deactivated" property returns a '1' if the chip has
		been temporarily dectivated, usually until the next power
		cycle. Whether a warm boot (reboot) will clear a TPM chip
		from a temp_deactivated state is platform specific.

		What: /sys/class/misc/tpmX/device/timeouts
		Date: March 2011
		KernelVersion: 3.1
		Contact: tpmdd-devel@lists.sf.net
		Description: The "timeouts" property shows the 4 vendor-specific values
		for the TPM's interface spec timeouts. The use of these
		timeouts is defined by the TPM interface spec that the chip
		conforms to.

		Example output:

		750000 750000 750000 750000 [original]

		The four timeout values are shown in usecs, with a trailing
		"[original]" or "[adjusted]" depending on whether the values
		were scaled by the driver to be reported in usec from msecs.