| 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 "<request> <response num> |
| : <response description>". |
| 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 "<action num>: <action |
| description>". |
| 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 "<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: 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. |
