systemd/units/tpm2.target

#  SPDX-License-Identifier: LGPL-2.1-or-later
#
#  This file is part of systemd.
#
#  systemd is free software; you can redistribute it and/or modify it
#  under the terms of the GNU Lesser General Public License as published by
#  the Free Software Foundation; either version 2.1 of the License, or
#  (at your option) any later version.

[Unit]
Description=Trusted Platform Module
Documentation=man:systemd.special(7)

# Make this a synchronization point on the first TPM device found
After=dev-tpmrm0.device
Wants=dev-tpmrm0.device
units: add a tpm2.target synchronization point and small generator that pulls in Distributions apparently only compile a subset of TPM2 drivers into the kernel. For those not compiled it but provided as kmod we need a synchronization point: we must wait before the first TPM2 interaction until the driver is available and accessible. This adds a tpm2.target unit as such a synchronization point. It's ordered after /dev/tpmrm0, and is pulled in by a generator whenever we detect that the kernel reported a TPM2 to exist but we have no device for it yet. This should solve the issue, but might create problems: if there are TPM devices supported by firmware that we don't have Linux drivers for we'll hang for a bit. Hence let's add a kernel cmdline switch to disable (or alternatively force) this logic. Fixes: #30164 2023-11-25 01:01:56 +08:00			`# SPDX-License-Identifier: LGPL-2.1-or-later`
			`#`
			`# This file is part of systemd.`
			`#`
			`# systemd is free software; you can redistribute it and/or modify it`
			`# under the terms of the GNU Lesser General Public License as published by`
			`# the Free Software Foundation; either version 2.1 of the License, or`
			`# (at your option) any later version.`

			`[Unit]`
			`Description=Trusted Platform Module`
			`Documentation=man:systemd.special(7)`

			`# Make this a synchronization point on the first TPM device found`
			`After=dev-tpmrm0.device`
			`Wants=dev-tpmrm0.device`