1 What: /sys/class/tpm/tpmX/ppi/ 2 Date: August 2012 3 KernelVersion: 3.6 4 Contact: xiaoyan.zhang@intel.com 5 Description: 6 This folder includes the attributes related with PPI (Physical 7 Presence Interface). Only if TPM is supported by BIOS, this 8 folder makes sense. The folder path can be got by command 9 'find /sys/ -name 'pcrs''. For the detail information of PPI, 10 please refer to the PPI specification from 11 12 http://www.trustedcomputinggroup.org/ 13 14 In Linux 4.2 ppi was moved to the character device directory. 15 A symlink from tpmX/device/ppi to tpmX/ppi to provide backwards 16 compatibility. 17 18 What: /sys/class/tpm/tpmX/ppi/version 19 Date: August 2012 20 Contact: xiaoyan.zhang@intel.com 21 Description: 22 This attribute shows the version of the PPI supported by the 23 platform. 24 This file is readonly. 25 26 What: /sys/class/tpm/tpmX/ppi/request 27 Date: August 2012 28 Contact: xiaoyan.zhang@intel.com 29 Description: 30 This attribute shows the request for an operation to be 31 executed in the pre-OS environment. It is the only input from 32 the OS to the pre-OS environment. The request should be an 33 integer value range from 1 to 160, and 0 means no request. 34 This file can be read and written. 35 36 What: /sys/class/tpm/tpmX/ppi/response 37 Date: August 2012 38 Contact: xiaoyan.zhang@intel.com 39 Description: 40 This attribute shows the response to the most recent operation 41 request it acted upon. The format is "<request> <response num> 42 : <response description>". 43 This file is readonly. 44 45 What: /sys/class/tpm/tpmX/ppi/transition_action 46 Date: August 2012 47 Contact: xiaoyan.zhang@intel.com 48 Description: 49 This attribute shows the platform-specific action that should 50 take place in order to transition to the BIOS for execution of 51 a requested operation. The format is "<action num>: <action 52 description>". 53 This file is readonly. 54 55 What: /sys/class/tpm/tpmX/ppi/tcg_operations 56 Date: August 2012 57 Contact: xiaoyan.zhang@intel.com 58 Description: 59 This attribute shows whether it is allowed to request an 60 operation to be executed in the pre-OS environment by the BIOS 61 for the requests defined by TCG, i.e. requests from 1 to 22. 62 The format is "<request> <status num>: <status description>". 63 This attribute is only supported by PPI version 1.2+. 64 This file is readonly. 65 66 What: /sys/class/tpm/tpmX/ppi/vs_operations 67 Date: August 2012 68 Contact: xiaoyan.zhang@intel.com 69 Description: 70 This attribute shows whether it is allowed to request an 71 operation to be executed in the pre-OS environment by the BIOS 72 for the verdor specific requests, i.e. requests from 128 to 73 255. The format is same with tcg_operations. This attribute 74 is also only supported by PPI version 1.2+. 75 This file is readonly.
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