systemd/man/systemd-tpm2-generator.xml

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<refentry id="systemd-tpm2-generator">

  <refentryinfo>
    <title>systemd-tpm2-generator</title>
    <productname>systemd</productname>
  </refentryinfo>

  <refmeta>
    <refentrytitle>systemd-tpm2-generator</refentrytitle>
    <manvolnum>8</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>systemd-tpm2-generator</refname>
    <refpurpose>Generator for inserting TPM2 synchronization point in the boot process</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <para><filename>/usr/lib/systemd/system-generators/systemd-tpm2-generator</filename></para>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><command>systemd-tpm2-generator</command> is a generator that adds a <varname>Wants=</varname>
    dependency from <filename>sysinit.target</filename> to <filename>tpm2.target</filename> when it detects
    that the firmware discovered a TPM2 device but the OS kernel so far did
    not. <filename>tpm2.target</filename> is supposed to act as synchronization point for all services that
    require TPM2 device access. See
    <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry> for
    details.</para>

    <para>The <option>systemd.tpm2_wait=</option> kernel command line option may be used to override
    behaviour of the generator. It accepts a boolean value: if true then <filename>tpm2.target</filename>
    will be added as synchronization point even if the firmware has not detected a TPM2 device. If false, the
    target will not be inserted even if firmware reported a device but the OS kernel doesn't expose a device
    for it yet. The latter might be useful in environments where a suitable TPM2 driver for the available
    hardware is not available.</para>

    <para><command>systemd-tpm2-generator</command> implements
    <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para><simplelist type="inline">
      <member><citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
      <member><citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry></member>
    </simplelist></para>
  </refsect1>
</refentry>