What: /sys/class/tpm/tpmX/ppi/ Date: August 2012 KernelVersion: 3.6 Contact: xiaoyan.zhang@intel.com 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: xiaoyan.zhang@intel.com 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: xiaoyan.zhang@intel.com 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: xiaoyan.zhang@intel.com Description: This attribute shows the response to the most recent operation request it acted upon. The format is " : ". This file is readonly. What: /sys/class/tpm/tpmX/ppi/transition_action Date: August 2012 Contact: xiaoyan.zhang@intel.com 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 ": ". This file is readonly. What: /sys/class/tpm/tpmX/ppi/tcg_operations Date: August 2012 Contact: xiaoyan.zhang@intel.com 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 " : ". 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: xiaoyan.zhang@intel.com 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.