Module tpm 

TPM 2.0 Support

Interface for Trusted Platform Module 2.0 operations including attestation, sealing, and hardware random number generation.

Hardware Integration Points

TPM hardware can be accessed via multiple interfaces:

• Memory-Mapped I/O (MMIO): Common on x86_64 platforms
  • Base addresses: 0xFED40000 (TPM1.2), 0xFED40000 (TPM2.0)
  • Registers: Access/Status/Data FIFOs at base + offsets
• I2C/SPI: Common on embedded platforms (ARM, RISC-V)
  • Requires I2C/SPI driver integration
  • Device addresses configurable via device tree
• Firmware Interface: UEFI/BIOS integration
  • Runtime services for TPM access
  • Platform-specific implementations

Implementation

Provides a full TPM 2.0 CRB (Command Response Buffer) interface over MMIO. When no hardware TPM is detected (common in QEMU without swtpm), the module runs in software-emulation mode with in-memory PCR banks, random number generation via the kernel PRNG, and software sealing/unsealing backed by SHA-256 key derivation.

For hardware TPM (e.g., QEMU + swtpm), the CRB interface marshals TPM 2.0 command packets to the MMIO command buffer and reads responses.

Modules

mmio

TPM MMIO base addresses and register offsets (platform-specific)

Structs

Tpm

TPM 2.0 interface

Enums

TpmCommand

TPM 2.0 command codes

TpmError

TPM errors

TpmInterfaceType

TPM Interface type

Functions

init

Initialize TPM support

is_available

Check if TPM is available

pcr_extend

Convenience: extend a PCR with a measurement hash via the global TPM instance.

pcr_read

Convenience: read a PCR value via the global TPM instance.

with_tpm

Execute a closure with a reference to the global TPM instance.

with_tpm_mut

Execute a closure with a mutable reference to the global TPM instance.

Type Aliases

PcrIndex

TPM Platform Configuration Register (PCR) index

TpmHandle

TPM handle for objects

TpmResult

TPM result