What: /sys/class/tpm/tpmX/ppi/
Date: August 2012
KernelVersion: 3.6
Contact: [email protected]
Description:
This folder includes the attributes related with PPI (Physical
Presence Interface). Only if TPM is supported by BIOS, this
folder makes sense. The folder path can be got by command
'find /sys/ -name 'pcrs''. For the detail information of PPI,
please refer to the PPI specification from
http://www.trustedcomputinggroup.org/
In Linux 4.2 ppi was moved to the character device directory.
A symlink from tpmX/device/ppi to tpmX/ppi to provide backwards
compatibility.
What: /sys/class/tpm/tpmX/ppi/version
Date: August 2012
Contact: [email protected]
Description:
This attribute shows the version of the PPI supported by the
platform.
This file is readonly.
What: /sys/class/tpm/tpmX/ppi/request
Date: August 2012
Contact: [email protected]
Description:
This attribute shows the request for an operation to be
executed in the pre-OS environment. It is the only input from
the OS to the pre-OS environment. The request should be an
integer value range from 1 to 160, and 0 means no request.
This file can be read and written.
What: /sys/class/tpm/tpmX/ppi/response
Date: August 2012
Contact: [email protected]
Description:
This attribute shows the response to the most recent operation
request it acted upon. The format is "<request> <response num>
: <response description>".
This file is readonly.
What: /sys/class/tpm/tpmX/ppi/transition_action
Date: August 2012
Contact: [email protected]
Description:
This attribute shows the platform-specific action that should
take place in order to transition to the BIOS for execution of
a requested operation. The format is "<action num>: <action
description>".
This file is readonly.
What: /sys/class/tpm/tpmX/ppi/tcg_operations
Date: August 2012
Contact: [email protected]
Description:
This attribute shows whether it is allowed to request an
operation to be executed in the pre-OS environment by the BIOS
for the requests defined by TCG, i.e. requests from 1 to 22.
The format is "<request> <status num>: <status description>".
This attribute is only supported by PPI version 1.2+.
This file is readonly.
What: /sys/class/tpm/tpmX/ppi/vs_operations
Date: August 2012
Contact: [email protected]
Description:
This attribute shows whether it is allowed to request an
operation to be executed in the pre-OS environment by the BIOS
for the verdor specific requests, i.e. requests from 128 to
255. The format is same with tcg_operations. This attribute
is also only supported by PPI version 1.2+.
This file is readonly.
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