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