2018-03-11 18:22:09 +08:00
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<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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2020-11-09 12:23:58 +08:00
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<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
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2018-03-11 18:22:09 +08:00
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2021-12-14 01:27:20 +08:00
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<refentry id="systemd-boot" conditional='HAVE_GNU_EFI'
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2018-03-11 18:22:09 +08:00
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xmlns:xi="http://www.w3.org/2001/XInclude">
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<refentryinfo>
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2018-06-15 13:25:22 +08:00
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<title>systemd-boot</title>
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2018-03-11 18:22:09 +08:00
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<productname>systemd</productname>
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</refentryinfo>
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<refmeta>
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2018-06-15 13:25:22 +08:00
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<refentrytitle>systemd-boot</refentrytitle>
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2018-03-11 18:22:09 +08:00
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<manvolnum>7</manvolnum>
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</refmeta>
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<refnamediv>
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2018-06-15 13:25:22 +08:00
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<refname>systemd-boot</refname>
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2018-03-11 18:22:09 +08:00
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<refname>sd-boot</refname>
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<refpurpose>A simple UEFI boot manager</refpurpose>
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</refnamediv>
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<refsect1>
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<title>Description</title>
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2019-02-12 23:13:57 +08:00
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<para><command>systemd-boot</command> (short: <command>sd-boot</command>) is a simple UEFI boot
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2021-09-21 22:52:57 +08:00
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manager. It provides a textual menu to select the entry to boot and an editor for the kernel command
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2019-02-12 23:13:57 +08:00
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line. <command>systemd-boot</command> supports systems with UEFI firmware only.</para>
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2018-06-20 17:59:11 +08:00
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2019-07-22 20:19:33 +08:00
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<para><command>systemd-boot</command> loads boot entry information from the EFI system partition (ESP),
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usually mounted at <filename>/efi/</filename>, <filename>/boot/</filename>, or
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2022-03-22 07:21:36 +08:00
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<filename>/boot/efi/</filename> during OS runtime, as well as from the Extended Boot Loader partition
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(XBOOTLDR) if it exists (usually mounted to <filename>/boot/</filename>). Configuration file fragments,
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kernels, initrds and other EFI images to boot generally need to reside on the ESP or the Extended Boot
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Loader partition. Linux kernels must be built with <option>CONFIG_EFI_STUB</option> to be able to be
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directly executed as an EFI image. During boot <command>systemd-boot</command> automatically assembles a
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list of boot entries from the following sources:</para>
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2018-06-20 17:59:11 +08:00
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<itemizedlist>
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<listitem><para>Boot entries defined with <ulink
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2022-03-21 19:16:35 +08:00
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url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> Type #1
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description files located in <filename>/loader/entries/</filename> on the ESP and the Extended Boot
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Loader Partition. These usually describe Linux kernel images with associated initrd images, but
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alternatively may also describe other arbitrary EFI executables.</para></listitem>
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2018-06-20 17:59:11 +08:00
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2022-03-21 19:16:35 +08:00
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<listitem><para>Unified kernel images, <ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot
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Loader Specification</ulink> Type #2, which are executable EFI binaries in
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<filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader Partition.</para></listitem>
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2018-06-20 17:59:11 +08:00
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2022-03-21 19:16:35 +08:00
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<listitem><para>The Microsoft Windows EFI boot manager, if installed.</para></listitem>
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2018-06-20 17:59:11 +08:00
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2022-03-21 19:16:35 +08:00
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<listitem><para>The Apple macOS boot manager, if installed.</para></listitem>
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2018-06-20 17:59:11 +08:00
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2022-03-21 19:16:35 +08:00
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<listitem><para>The EFI Shell binary, if installed.</para></listitem>
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2018-06-20 17:59:11 +08:00
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2022-03-21 19:16:35 +08:00
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<listitem><para>A reboot into the UEFI firmware setup option, if supported by the firmware.</para></listitem>
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This patch adds support for enrolling secure boot boot keys from sd-boot.
***DANGER*** NOTE ***DANGER***
This feature might result in your device becoming soft-brick as outlined
below, please use this feature carefully.
***DANGER*** NOTE ***DANGER***
If secure-boot-enrollment is set to no, then no action whatsoever is performed,
no matter the files on the ESP.
If secure boot keys are found under $ESP/loader/keys and secure-boot-enrollment
is set to either manual or force then sd-boot will generate enrollment entries
named after the directories they are in. The entries are shown at the very bottom
of the list and can be selected by the user from the menu. If the user selects it,
the user is shown a screen allowing for cancellation before a timeout. The enrollment
proceeds if the action is not cancelled after the timeout.
Additionally, if the secure-boot-enroll option is set to 'force' then the keys
located in the directory named 'auto' are going to be enrolled automatically. The user
is still going to be shown a screen allowing them to cancel the action if they want to,
however the enrollment will proceed automatically after a timeout without
user cancellation.
After keys are enrolled, the system reboots with secure boot enabled therefore, it is
***critical*** to ensure that everything needed for the system to boot is signed
properly (sd-boot itself, kernel, initramfs, PCI option ROMs).
This feature currently only allows loading the most simple set of variables: PK, KEK
and db.
The files need to be prepared with cert-to-efi-sig-list and then signed with
sign-efi-sig-list.
Here is a short example to generate your own keys and the right files for
auto-enrollement.
`
keys="PK KEK DB"
uuid="{$(systemd-id128 new -u)}"
for key in ${keys}; do
openssl req -new -x509 -subj "/CN=${key}/ -keyout "${key}.key" -out "${key}.crt"
openssl x509 -outform DER -in "${key}.crt" -out "${key}.cer"
cert-to-efi-sig-list -g "${uuid}" "${key}.crt" "${key}.esl.nosign"
done
sign-efi-sig-list -c PK.crt -k PK.key PK PK.esl.nosign PK.esl
sign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl.nosign KEK.esl
sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl.nosign db.esl
`
Once these keys are enrolled, all the files needed for boot ***NEED*** to be signed in
order to run. You can sign the binaries with the sbsign tool, for example:
`
sbsign --key db.key --cert db.crt bzImage --output $ESP/bzImage
`
Example:
Assuming the system has been put in Setup Mode:
`
$ESP/loader/keys/auto/db.esl
$ESP/loader/keys/auto/KEK.esl
$ESP/loader/keys/auto/PK.esl
$ESP/loader/keys/Linux Only/db.esl
$ESP/loader/keys/Linux Only/KEK.esl
$ESP/loader/keys/Linux Only/PK.esl
$ESP/loader/keys/Linux and Windows/db.esl
$ESP/loader/keys/Linux and Windows/KEK.esl
$ESP/loader/keys/Linux and Windows/PK.esl
`
If auto-enroll is set, then the db, KEK and then PK are enrolled from the 'auto'
directory.
If not, three new boot entries are available to the user in order to enroll either the
'Linux Only', 'Linux And Windows' or 'auto' set of keys.
2022-05-10 02:13:28 +08:00
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<listitem><para>Secure boot variables enrollement if the UEFI firmware is in setup-mode and files are provided
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on the ESP.</para></listitem>
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2018-06-20 17:59:11 +08:00
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</itemizedlist>
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2019-07-22 20:19:33 +08:00
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<para><command>systemd-boot</command> supports the following features:</para>
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<itemizedlist>
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<listitem><para>Basic boot manager configuration changes (such as timeout
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configuration, default boot entry selection, …) may be made directly from the boot loader UI at
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boot-time, as well as during system runtime with EFI variables.</para></listitem>
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<listitem><para>The boot manager integrates with the <command>systemctl</command> command to implement
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features such as <command>systemctl reboot --boot-loader-entry=…</command> (for rebooting into a
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specific boot menu entry, i.e. "reboot into Windows") and <command>systemctl reboot
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--boot-loader-menu=…</command> (for rebooting into the boot loader menu), by implementing the <ulink
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url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. See
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<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> for
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details.</para></listitem>
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2021-07-09 17:56:54 +08:00
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<listitem><para>An EFI variable set by the boot loader informs the OS about the EFI System Partition used
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during boot. This is then used to automatically mount the correct EFI System Partition to
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2019-07-22 20:19:33 +08:00
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<filename>/efi/</filename> or <filename>/boot/</filename> during OS runtime. See
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<citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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for details.</para></listitem>
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<listitem><para>The boot manager provides information about the boot time spent in UEFI firmware using
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the <ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>. This
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information can be displayed using
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<citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>.
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</para></listitem>
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<listitem><para>The boot manager implements boot counting and automatic fallback to older, working boot
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entries on failure. See <ulink url="https://systemd.io/AUTOMATIC_BOOT_ASSESSMENT">Automatic Boot
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Assessment</ulink>.</para></listitem>
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<listitem><para>The boot manager optionally reads a random seed from the ESP partition, combines it
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2019-12-24 20:50:04 +08:00
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with a 'system token' stored in a persistent EFI variable and derives a random seed to use by the OS as
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2020-07-06 16:49:59 +08:00
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entropy pool initialization, providing a full entropy pool during early boot.</para></listitem>
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This patch adds support for enrolling secure boot boot keys from sd-boot.
***DANGER*** NOTE ***DANGER***
This feature might result in your device becoming soft-brick as outlined
below, please use this feature carefully.
***DANGER*** NOTE ***DANGER***
If secure-boot-enrollment is set to no, then no action whatsoever is performed,
no matter the files on the ESP.
If secure boot keys are found under $ESP/loader/keys and secure-boot-enrollment
is set to either manual or force then sd-boot will generate enrollment entries
named after the directories they are in. The entries are shown at the very bottom
of the list and can be selected by the user from the menu. If the user selects it,
the user is shown a screen allowing for cancellation before a timeout. The enrollment
proceeds if the action is not cancelled after the timeout.
Additionally, if the secure-boot-enroll option is set to 'force' then the keys
located in the directory named 'auto' are going to be enrolled automatically. The user
is still going to be shown a screen allowing them to cancel the action if they want to,
however the enrollment will proceed automatically after a timeout without
user cancellation.
After keys are enrolled, the system reboots with secure boot enabled therefore, it is
***critical*** to ensure that everything needed for the system to boot is signed
properly (sd-boot itself, kernel, initramfs, PCI option ROMs).
This feature currently only allows loading the most simple set of variables: PK, KEK
and db.
The files need to be prepared with cert-to-efi-sig-list and then signed with
sign-efi-sig-list.
Here is a short example to generate your own keys and the right files for
auto-enrollement.
`
keys="PK KEK DB"
uuid="{$(systemd-id128 new -u)}"
for key in ${keys}; do
openssl req -new -x509 -subj "/CN=${key}/ -keyout "${key}.key" -out "${key}.crt"
openssl x509 -outform DER -in "${key}.crt" -out "${key}.cer"
cert-to-efi-sig-list -g "${uuid}" "${key}.crt" "${key}.esl.nosign"
done
sign-efi-sig-list -c PK.crt -k PK.key PK PK.esl.nosign PK.esl
sign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl.nosign KEK.esl
sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl.nosign db.esl
`
Once these keys are enrolled, all the files needed for boot ***NEED*** to be signed in
order to run. You can sign the binaries with the sbsign tool, for example:
`
sbsign --key db.key --cert db.crt bzImage --output $ESP/bzImage
`
Example:
Assuming the system has been put in Setup Mode:
`
$ESP/loader/keys/auto/db.esl
$ESP/loader/keys/auto/KEK.esl
$ESP/loader/keys/auto/PK.esl
$ESP/loader/keys/Linux Only/db.esl
$ESP/loader/keys/Linux Only/KEK.esl
$ESP/loader/keys/Linux Only/PK.esl
$ESP/loader/keys/Linux and Windows/db.esl
$ESP/loader/keys/Linux and Windows/KEK.esl
$ESP/loader/keys/Linux and Windows/PK.esl
`
If auto-enroll is set, then the db, KEK and then PK are enrolled from the 'auto'
directory.
If not, three new boot entries are available to the user in order to enroll either the
'Linux Only', 'Linux And Windows' or 'auto' set of keys.
2022-05-10 02:13:28 +08:00
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<listitem><para>The boot manager allows for secure boot variables to be enrolled if the UEFI firmware is
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in setup-mode. Additionally, variables can be automatically enrolled if configured.</para></listitem>
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2019-07-22 20:19:33 +08:00
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</itemizedlist>
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<para><citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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2019-02-12 23:13:57 +08:00
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may be used from a running system to locate the ESP and the Extended Boot Loader Partition, list
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available entries, and install <command>systemd-boot</command> itself.</para>
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2018-06-20 17:59:11 +08:00
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2019-07-22 20:19:33 +08:00
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<para><citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry>
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may be used to copy kernel images onto the ESP or the Extended Boot Loader Partition and to generate
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description files compliant with the Boot Loader
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Specification.</para>
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2021-09-21 22:52:24 +08:00
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<para><citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>
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may be used as UEFI boot stub for executed kernels, which is useful to show graphical boot splashes
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before transitioning into the Linux world. It is also capable of automatically picking up auxiliary
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credential files (for boot parameterization) and system extension images, as companion files to the
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booted kernel images.</para>
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2018-03-11 18:22:09 +08:00
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</refsect1>
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<refsect1>
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<title>Key bindings</title>
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<para>The following keys may be used in the boot menu:</para>
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2021-08-14 20:26:12 +08:00
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<!-- Developer commands Q/v/Ctrl+l deliberately not advertised. -->
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2018-03-11 18:22:09 +08:00
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<variablelist>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>↑</keycap> (Up)</term>
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<term><keycap>↓</keycap> (Down)</term>
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<term><keycap>j</keycap></term>
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<term><keycap>k</keycap></term>
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<term><keycap>PageUp</keycap></term>
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<term><keycap>PageDown</keycap></term>
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<term><keycap>Home</keycap></term>
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<term><keycap>End</keycap></term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Navigate up/down in the entry list</para></listitem>
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</varlistentry>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>↵</keycap> (Enter)</term>
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2020-04-15 20:18:15 +08:00
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<term><keycap>→</keycap> (Right)</term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Boot selected entry</para></listitem>
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</varlistentry>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>d</keycap></term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Make selected entry the default</para></listitem>
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</varlistentry>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>e</keycap></term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Edit the kernel command line for selected entry</para></listitem>
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</varlistentry>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>+</keycap></term>
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<term><keycap>t</keycap></term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Increase the timeout before default entry is booted</para></listitem>
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</varlistentry>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>-</keycap></term>
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<term><keycap>T</keycap></term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Decrease the timeout</para></listitem>
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</varlistentry>
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2021-08-15 19:44:47 +08:00
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<varlistentry>
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<term><keycap>r</keycap></term>
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<listitem><para>Change screen resolution, skipping any unsupported modes.</para></listitem>
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</varlistentry>
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<varlistentry>
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<term><keycap>R</keycap></term>
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<listitem><para>Reset screen resolution to firmware or configuration file default.</para></listitem>
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</varlistentry>
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2018-03-11 18:22:09 +08:00
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<varlistentry>
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2021-08-14 20:26:12 +08:00
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<term><keycap>p</keycap></term>
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2018-03-11 18:22:09 +08:00
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<listitem><para>Print status</para></listitem>
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</varlistentry>
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<varlistentry>
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2018-06-28 02:31:34 +08:00
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<term><keycap>h</keycap></term>
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<term><keycap>?</keycap></term>
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2020-07-15 01:31:21 +08:00
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<term><keycap>F1</keycap></term>
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2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Show a help screen</para></listitem>
|
|
|
|
|
</varlistentry>
|
2021-10-20 18:15:03 +08:00
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
|
<term><keycap>f</keycap></term>
|
|
|
|
|
<listitem><para>Reboot into firmware interface.</para>
|
|
|
|
|
|
|
|
|
|
<para>For compatibility with the keybindings of several firmware implementations this operation
|
|
|
|
|
may also be reached with <keycap>F2</keycap>, <keycap>F10</keycap>, <keycap>Del</keycap> and
|
|
|
|
|
<keycap>Esc</keycap>.</para></listitem>
|
|
|
|
|
</varlistentry>
|
2018-03-11 18:22:09 +08:00
|
|
|
</variablelist>
|
|
|
|
|
|
2020-04-21 17:18:56 +08:00
|
|
|
<para>The following keys may be pressed during bootup or in the boot menu to directly boot a specific
|
|
|
|
|
entry:</para>
|
2018-03-11 18:22:09 +08:00
|
|
|
|
|
|
|
|
<variablelist>
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>l</keycap></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Linux</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>w</keycap></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Windows</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>a</keycap></term>
|
2021-04-02 16:03:02 +08:00
|
|
|
<listitem><para>macOS</para></listitem>
|
2018-03-11 18:22:09 +08:00
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>s</keycap></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>EFI shell</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>1</keycap></term>
|
|
|
|
|
<term><keycap>2</keycap></term>
|
|
|
|
|
<term><keycap>3</keycap></term>
|
|
|
|
|
<term><keycap>4</keycap></term>
|
|
|
|
|
<term><keycap>5</keycap></term>
|
|
|
|
|
<term><keycap>6</keycap></term>
|
|
|
|
|
<term><keycap>7</keycap></term>
|
|
|
|
|
<term><keycap>8</keycap></term>
|
|
|
|
|
<term><keycap>9</keycap></term>
|
2018-06-20 17:59:11 +08:00
|
|
|
<listitem><para>Boot entry number 1 … 9</para></listitem>
|
2018-03-11 18:22:09 +08:00
|
|
|
</varlistentry>
|
|
|
|
|
</variablelist>
|
|
|
|
|
|
2020-04-21 17:18:56 +08:00
|
|
|
<para>The boot menu is shown when a non-zero menu timeout has been configured. If the menu timeout has
|
|
|
|
|
been set to zero, it is sufficient to press any key — before the boot loader initializes — to bring up
|
|
|
|
|
the boot menu, except for the keys listed immediately above as they directly boot into the selected boot
|
|
|
|
|
menu item. Note that depending on the firmware implementation the time window where key presses are
|
|
|
|
|
accepted before the boot loader initializes might be short. If the window is missed, reboot and try
|
|
|
|
|
again, possibly pressing a suitable key (e.g. the space bar) continuously; on most systems it should be
|
|
|
|
|
possible to hit the time window after a few attempts. To avoid this problem, consider setting a non-zero
|
|
|
|
|
timeout, thus showing the boot menu unconditionally. Some desktop environments might offer an option to
|
|
|
|
|
directly boot into the boot menu, to avoid the problem altogether. Alternatively, use the command line
|
|
|
|
|
<command>systemctl reboot --boot-loader-menu=0</command> from the shell.</para>
|
|
|
|
|
|
2018-03-11 18:22:09 +08:00
|
|
|
<para>In the editor, most keys simply insert themselves, but the following keys
|
|
|
|
|
may be used to perform additional actions:</para>
|
|
|
|
|
|
|
|
|
|
<variablelist>
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>←</keycap> (Left)</term>
|
|
|
|
|
<term><keycap>→</keycap> (Right)</term>
|
|
|
|
|
<term><keycap>Home</keycap></term>
|
|
|
|
|
<term><keycap>End</keycap></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Navigate left/right</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>Esc</keycap></term>
|
2022-08-29 16:39:49 +08:00
|
|
|
<term><keycombo><keycap>Ctrl</keycap><keycap>c</keycap></keycombo></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Abort the edit and quit the editor</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycombo><keycap>Ctrl</keycap><keycap>k</keycap></keycombo></term>
|
2022-08-29 16:39:49 +08:00
|
|
|
<listitem><para>Clear the command line forwards</para></listitem>
|
2018-03-11 18:22:09 +08:00
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycombo><keycap>Ctrl</keycap><keycap>w</keycap></keycombo></term>
|
|
|
|
|
<term><keycombo><keycap>Alt</keycap><keycap>Backspace</keycap></keycombo></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Delete word backwards</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2022-08-29 16:39:49 +08:00
|
|
|
<term><keycombo><keycap>Ctrl</keycap><keycap>Del</keycap></keycombo></term>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycombo><keycap>Alt</keycap><keycap>d</keycap></keycombo></term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Delete word forwards</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
2018-06-28 02:31:34 +08:00
|
|
|
<term><keycap>↵</keycap> (Enter)</term>
|
2018-03-11 18:22:09 +08:00
|
|
|
<listitem><para>Boot entry with the edited command line</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
</variablelist>
|
|
|
|
|
|
2018-06-15 13:25:22 +08:00
|
|
|
<para>Note that unless configured otherwise in the UEFI firmware, systemd-boot will
|
2018-03-11 18:22:09 +08:00
|
|
|
use the US keyboard layout, so key labels might not match for keys like +/-.
|
|
|
|
|
</para>
|
|
|
|
|
</refsect1>
|
|
|
|
|
|
2018-06-20 17:59:11 +08:00
|
|
|
<refsect1>
|
|
|
|
|
<title>Files</title>
|
|
|
|
|
|
2019-02-12 23:13:57 +08:00
|
|
|
<para>The files <command>systemd-boot</command> processes generally reside on the UEFI ESP which is
|
|
|
|
|
usually mounted to <filename>/efi/</filename>, <filename>/boot/</filename> or
|
|
|
|
|
<filename>/boot/efi/</filename> during OS runtime. It also processes files on the Extended Boot Loader
|
|
|
|
|
partition which is typically mounted to <filename>/boot/</filename>, if it
|
2021-09-21 23:28:16 +08:00
|
|
|
exists.</para>
|
|
|
|
|
|
|
|
|
|
<para><command>systemd-boot</command> reads runtime configuration such as the boot timeout and default
|
2019-02-12 23:13:57 +08:00
|
|
|
entry from <filename>/loader/loader.conf</filename> on the ESP (in combination with data read from EFI
|
|
|
|
|
variables). See
|
2021-09-21 23:28:16 +08:00
|
|
|
<citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
|
|
|
|
|
|
|
|
|
|
<para>Boot entry description files following the <ulink
|
|
|
|
|
url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> are read from
|
|
|
|
|
<filename>/loader/entries/</filename> on the ESP and the Extended Boot Loader partition.</para>
|
|
|
|
|
|
|
|
|
|
<para>Unified kernel boot entries following the <ulink
|
2019-02-12 23:13:57 +08:00
|
|
|
url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink> are read from
|
2021-09-21 23:28:16 +08:00
|
|
|
<filename>/EFI/Linux/</filename> on the ESP and the Extended Boot Loader partition.</para>
|
|
|
|
|
|
|
|
|
|
<para>Optionally, a random seed for early boot entropy pool provisioning is stored in
|
|
|
|
|
<filename>/loader/random-seed</filename> in the ESP.</para>
|
|
|
|
|
|
|
|
|
|
<para>During initialization, <command>sd-boot</command> automatically loads all driver files placed in
|
|
|
|
|
the <filename>/EFI/systemd/drivers/</filename> directory of the ESP. The files placed there must have an
|
|
|
|
|
extension of the EFI architecture ID followed by <filename>.efi</filename> (e.g. for x86-64 this means a
|
|
|
|
|
suffix of <filename>x64.efi</filename>). This may be used to automatically load file system drivers and
|
|
|
|
|
similar, to extend the native firmware support.</para>
|
This patch adds support for enrolling secure boot boot keys from sd-boot.
***DANGER*** NOTE ***DANGER***
This feature might result in your device becoming soft-brick as outlined
below, please use this feature carefully.
***DANGER*** NOTE ***DANGER***
If secure-boot-enrollment is set to no, then no action whatsoever is performed,
no matter the files on the ESP.
If secure boot keys are found under $ESP/loader/keys and secure-boot-enrollment
is set to either manual or force then sd-boot will generate enrollment entries
named after the directories they are in. The entries are shown at the very bottom
of the list and can be selected by the user from the menu. If the user selects it,
the user is shown a screen allowing for cancellation before a timeout. The enrollment
proceeds if the action is not cancelled after the timeout.
Additionally, if the secure-boot-enroll option is set to 'force' then the keys
located in the directory named 'auto' are going to be enrolled automatically. The user
is still going to be shown a screen allowing them to cancel the action if they want to,
however the enrollment will proceed automatically after a timeout without
user cancellation.
After keys are enrolled, the system reboots with secure boot enabled therefore, it is
***critical*** to ensure that everything needed for the system to boot is signed
properly (sd-boot itself, kernel, initramfs, PCI option ROMs).
This feature currently only allows loading the most simple set of variables: PK, KEK
and db.
The files need to be prepared with cert-to-efi-sig-list and then signed with
sign-efi-sig-list.
Here is a short example to generate your own keys and the right files for
auto-enrollement.
`
keys="PK KEK DB"
uuid="{$(systemd-id128 new -u)}"
for key in ${keys}; do
openssl req -new -x509 -subj "/CN=${key}/ -keyout "${key}.key" -out "${key}.crt"
openssl x509 -outform DER -in "${key}.crt" -out "${key}.cer"
cert-to-efi-sig-list -g "${uuid}" "${key}.crt" "${key}.esl.nosign"
done
sign-efi-sig-list -c PK.crt -k PK.key PK PK.esl.nosign PK.esl
sign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl.nosign KEK.esl
sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl.nosign db.esl
`
Once these keys are enrolled, all the files needed for boot ***NEED*** to be signed in
order to run. You can sign the binaries with the sbsign tool, for example:
`
sbsign --key db.key --cert db.crt bzImage --output $ESP/bzImage
`
Example:
Assuming the system has been put in Setup Mode:
`
$ESP/loader/keys/auto/db.esl
$ESP/loader/keys/auto/KEK.esl
$ESP/loader/keys/auto/PK.esl
$ESP/loader/keys/Linux Only/db.esl
$ESP/loader/keys/Linux Only/KEK.esl
$ESP/loader/keys/Linux Only/PK.esl
$ESP/loader/keys/Linux and Windows/db.esl
$ESP/loader/keys/Linux and Windows/KEK.esl
$ESP/loader/keys/Linux and Windows/PK.esl
`
If auto-enroll is set, then the db, KEK and then PK are enrolled from the 'auto'
directory.
If not, three new boot entries are available to the user in order to enroll either the
'Linux Only', 'Linux And Windows' or 'auto' set of keys.
2022-05-10 02:13:28 +08:00
|
|
|
|
|
|
|
|
<para>Enrollment of Secure Boot variables can be performed manually or automatically if files are available
|
2022-08-03 17:27:38 +08:00
|
|
|
under <filename>/keys/<replaceable>NAME</replaceable>/{db,KEK,PK}.auth</filename>, <replaceable>NAME</replaceable>
|
This patch adds support for enrolling secure boot boot keys from sd-boot.
***DANGER*** NOTE ***DANGER***
This feature might result in your device becoming soft-brick as outlined
below, please use this feature carefully.
***DANGER*** NOTE ***DANGER***
If secure-boot-enrollment is set to no, then no action whatsoever is performed,
no matter the files on the ESP.
If secure boot keys are found under $ESP/loader/keys and secure-boot-enrollment
is set to either manual or force then sd-boot will generate enrollment entries
named after the directories they are in. The entries are shown at the very bottom
of the list and can be selected by the user from the menu. If the user selects it,
the user is shown a screen allowing for cancellation before a timeout. The enrollment
proceeds if the action is not cancelled after the timeout.
Additionally, if the secure-boot-enroll option is set to 'force' then the keys
located in the directory named 'auto' are going to be enrolled automatically. The user
is still going to be shown a screen allowing them to cancel the action if they want to,
however the enrollment will proceed automatically after a timeout without
user cancellation.
After keys are enrolled, the system reboots with secure boot enabled therefore, it is
***critical*** to ensure that everything needed for the system to boot is signed
properly (sd-boot itself, kernel, initramfs, PCI option ROMs).
This feature currently only allows loading the most simple set of variables: PK, KEK
and db.
The files need to be prepared with cert-to-efi-sig-list and then signed with
sign-efi-sig-list.
Here is a short example to generate your own keys and the right files for
auto-enrollement.
`
keys="PK KEK DB"
uuid="{$(systemd-id128 new -u)}"
for key in ${keys}; do
openssl req -new -x509 -subj "/CN=${key}/ -keyout "${key}.key" -out "${key}.crt"
openssl x509 -outform DER -in "${key}.crt" -out "${key}.cer"
cert-to-efi-sig-list -g "${uuid}" "${key}.crt" "${key}.esl.nosign"
done
sign-efi-sig-list -c PK.crt -k PK.key PK PK.esl.nosign PK.esl
sign-efi-sig-list -c PK.crt -k PK.key KEK KEK.esl.nosign KEK.esl
sign-efi-sig-list -c KEK.crt -k KEK.key db db.esl.nosign db.esl
`
Once these keys are enrolled, all the files needed for boot ***NEED*** to be signed in
order to run. You can sign the binaries with the sbsign tool, for example:
`
sbsign --key db.key --cert db.crt bzImage --output $ESP/bzImage
`
Example:
Assuming the system has been put in Setup Mode:
`
$ESP/loader/keys/auto/db.esl
$ESP/loader/keys/auto/KEK.esl
$ESP/loader/keys/auto/PK.esl
$ESP/loader/keys/Linux Only/db.esl
$ESP/loader/keys/Linux Only/KEK.esl
$ESP/loader/keys/Linux Only/PK.esl
$ESP/loader/keys/Linux and Windows/db.esl
$ESP/loader/keys/Linux and Windows/KEK.esl
$ESP/loader/keys/Linux and Windows/PK.esl
`
If auto-enroll is set, then the db, KEK and then PK are enrolled from the 'auto'
directory.
If not, three new boot entries are available to the user in order to enroll either the
'Linux Only', 'Linux And Windows' or 'auto' set of keys.
2022-05-10 02:13:28 +08:00
|
|
|
being the display name for the set of variables in the menu. If one of the sets is named <filename>auto</filename>
|
|
|
|
|
then it might be enrolled automatically depending on whether <literal>secure-boot-enroll</literal> is set
|
|
|
|
|
to force or not.</para>
|
2018-06-20 17:59:11 +08:00
|
|
|
</refsect1>
|
|
|
|
|
|
2018-06-26 03:48:33 +08:00
|
|
|
<refsect1>
|
|
|
|
|
<title>EFI Variables</title>
|
|
|
|
|
|
2021-09-21 22:52:57 +08:00
|
|
|
<para>The following EFI variables are defined, set and read by <command>systemd-boot</command>, under the
|
|
|
|
|
vendor UUID <literal>4a67b082-0a4c-41cf-b6c7-440b29bb8c4f</literal>, for communication between the boot
|
|
|
|
|
loader and the OS:</para>
|
2018-06-26 03:48:33 +08:00
|
|
|
|
2019-02-13 18:09:02 +08:00
|
|
|
<variablelist class='efi-variables'>
|
2018-06-26 03:48:33 +08:00
|
|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderBootCountPath</varname></term>
|
|
|
|
|
<listitem><para>If boot counting is enabled, contains the path to the file in whose name the boot counters are
|
|
|
|
|
encoded. Set by the boot
|
|
|
|
|
loader. <citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
|
|
|
uses this information to mark a boot as successful as determined by the successful activation of the
|
|
|
|
|
<filename>boot-complete.target</filename> target unit.</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderConfigTimeout</varname></term>
|
2018-10-22 19:40:51 +08:00
|
|
|
<term><varname>LoaderConfigTimeoutOneShot</varname></term>
|
2018-12-14 15:26:46 +08:00
|
|
|
<listitem><para>The menu timeout in seconds. Read by the boot loader. <varname>LoaderConfigTimeout</varname>
|
2018-10-22 19:40:51 +08:00
|
|
|
is maintained persistently, while <varname>LoaderConfigTimeoutOneShot</varname> is a one-time override which is
|
|
|
|
|
read once (in which case it takes precedence over <varname>LoaderConfigTimeout</varname>) and then
|
|
|
|
|
removed. <varname>LoaderConfigTimeout</varname> may be manipulated with the
|
2020-07-06 16:49:59 +08:00
|
|
|
<keycap>t</keycap>/<keycap>T</keycap> keys, see above.</para></listitem>
|
2018-06-26 03:48:33 +08:00
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderDevicePartUUID</varname></term>
|
|
|
|
|
|
|
|
|
|
<listitem><para>Contains the partition UUID of the EFI System Partition the boot loader was run from. Set by
|
|
|
|
|
the boot
|
|
|
|
|
loader. <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
|
|
|
uses this information to automatically find the disk booted from, in order to discover various other partitions
|
|
|
|
|
on the same disk automatically.</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderEntries</varname></term>
|
|
|
|
|
|
|
|
|
|
<listitem><para>A list of the identifiers of all discovered boot loader entries. Set by the boot
|
|
|
|
|
loader.</para></listitem>
|
|
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</varlistentry>
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<varlistentry>
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<term><varname>LoaderEntryDefault</varname></term>
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|
<term><varname>LoaderEntryOneShot</varname></term>
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|
<listitem><para>The identifier of the default boot loader entry. Set primarily by the OS and read by the boot
|
|
|
|
|
loader. <varname>LoaderEntryOneShot</varname> sets the default entry for the next boot only, while
|
|
|
|
|
<varname>LoaderEntryDefault</varname> sets it persistently for all future
|
|
|
|
|
boots. <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
|
|
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|
|
<option>set-default</option> and <option>set-oneshot</option> commands make use of these variables. The boot
|
|
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|
|
loader modifies <varname>LoaderEntryDefault</varname> on request, when the <keycap>d</keycap> key is used, see
|
2020-07-07 01:46:01 +08:00
|
|
|
above.</para></listitem>
|
2018-06-26 03:48:33 +08:00
|
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</varlistentry>
|
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<varlistentry>
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|
<term><varname>LoaderEntrySelected</varname></term>
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|
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|
<listitem><para>The identifier of the boot loader entry currently being booted. Set by the boot
|
|
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|
|
loader.</para></listitem>
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</varlistentry>
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|
2018-10-22 22:51:46 +08:00
|
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<varlistentry>
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|
<term><varname>LoaderFeatures</varname></term>
|
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|
|
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|
|
<listitem><para>A set of flags indicating the features the boot loader supports. Set by the boot loader. Use
|
|
|
|
|
<citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this
|
|
|
|
|
data.</para></listitem>
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</varlistentry>
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|
2018-06-26 03:48:33 +08:00
|
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<varlistentry>
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<term><varname>LoaderFirmwareInfo</varname></term>
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|
<term><varname>LoaderFirmwareType</varname></term>
|
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|
<listitem><para>Brief firmware information. Set by the boot loader. Use
|
|
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|
|
<citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this
|
|
|
|
|
data.</para></listitem>
|
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</varlistentry>
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<varlistentry>
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|
<term><varname>LoaderImageIdentifier</varname></term>
|
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|
|
<listitem><para>The path of executable of the boot loader used for the current boot, relative to the EFI System
|
|
|
|
|
Partition's root directory. Set by the boot loader. Use
|
|
|
|
|
<citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this
|
|
|
|
|
data.</para></listitem>
|
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|
|
</varlistentry>
|
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<varlistentry>
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|
<term><varname>LoaderInfo</varname></term>
|
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|
|
|
|
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|
|
<listitem><para>Brief information about the boot loader. Set by the boot loader. Use
|
|
|
|
|
<citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry> to view this
|
|
|
|
|
data.</para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
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|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderTimeExecUSec</varname></term>
|
|
|
|
|
<term><varname>LoaderTimeInitUSec</varname></term>
|
|
|
|
|
<term><varname>LoaderTimeMenuUsec</varname></term>
|
|
|
|
|
|
|
|
|
|
<listitem><para>Information about the time spent in various parts of the boot loader. Set by the boot
|
|
|
|
|
loader. Use <citerefentry><refentrytitle>systemd-analyze</refentrytitle><manvolnum>1</manvolnum></citerefentry>
|
2019-07-22 20:19:33 +08:00
|
|
|
to view this data. </para></listitem>
|
|
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderRandomSeed</varname></term>
|
|
|
|
|
|
|
|
|
|
<listitem><para>A binary random seed <command>systemd-boot</command> may optionally pass to the
|
|
|
|
|
OS. This is a volatile EFI variable that is hashed at boot from the combination of a random seed
|
|
|
|
|
stored in the ESP (in <filename>/loader/random-seed</filename>) and a "system token" persistently
|
|
|
|
|
stored in the EFI variable <varname>LoaderSystemToken</varname> (see below). During early OS boot the
|
|
|
|
|
system manager reads this variable and passes it to the OS kernel's random pool, crediting the full
|
|
|
|
|
entropy it contains. This is an efficient way to ensure the system starts up with a fully initialized
|
|
|
|
|
kernel random pool — as early as the initial RAM disk phase. <command>systemd-boot</command> reads
|
|
|
|
|
the random seed from the ESP, combines it with the "system token", and both derives a new random seed
|
|
|
|
|
to update in-place the seed stored in the ESP, and the random seed to pass to the OS from it via
|
|
|
|
|
SHA256 hashing in counter mode. This ensures that different physical systems that boot the same
|
|
|
|
|
"golden" OS image — i.e. containing the same random seed file in the ESP — will still pass a
|
|
|
|
|
different random seed to the OS. It is made sure the random seed stored in the ESP is fully
|
|
|
|
|
overwritten before the OS is booted, to ensure different random seed data is used between subsequent
|
2019-07-23 00:13:26 +08:00
|
|
|
boots.</para>
|
|
|
|
|
|
|
|
|
|
<para>See <ulink url="https://systemd.io/RANDOM_SEEDS">Random Seeds</ulink> for
|
|
|
|
|
further information.</para></listitem>
|
2019-07-22 20:19:33 +08:00
|
|
|
</varlistentry>
|
|
|
|
|
|
|
|
|
|
<varlistentry>
|
|
|
|
|
<term><varname>LoaderSystemToken</varname></term>
|
|
|
|
|
|
2020-07-06 16:49:59 +08:00
|
|
|
<listitem><para>A binary random data field, that is used for generating the random seed to pass to
|
|
|
|
|
the OS (see above). Note that this random data is generally only generated once, during OS
|
|
|
|
|
installation, and is then never updated again.</para></listitem>
|
2018-06-26 03:48:33 +08:00
|
|
|
</varlistentry>
|
|
|
|
|
</variablelist>
|
2019-07-22 20:19:33 +08:00
|
|
|
|
|
|
|
|
<para>Many of these variables are defined by the <ulink
|
|
|
|
|
url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>.</para>
|
2018-06-26 03:48:33 +08:00
|
|
|
</refsect1>
|
|
|
|
|
|
2018-06-27 04:11:35 +08:00
|
|
|
<refsect1>
|
|
|
|
|
<title>Boot Counting</title>
|
|
|
|
|
|
|
|
|
|
<para><command>systemd-boot</command> implements a simple boot counting mechanism on top of the <ulink
|
|
|
|
|
url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink>, for automatic and unattended
|
2019-04-27 08:22:40 +08:00
|
|
|
fallback to older kernel versions/boot loader entries when a specific entry continuously fails. Any boot loader
|
2018-06-27 04:11:35 +08:00
|
|
|
entry file and unified kernel image file that contains a <literal>+</literal> followed by one or two numbers (if
|
|
|
|
|
two they need to be separated by a <literal>-</literal>), before the <filename>.conf</filename> or
|
|
|
|
|
<filename>.efi</filename> suffix is subject to boot counting: the first of the two numbers ('tries left') is
|
|
|
|
|
decreased by one on every boot attempt, the second of the two numbers ('tries done') is increased by one (if 'tries
|
|
|
|
|
done' is absent it is considered equivalent to 0). Depending on the current value of these two counters the boot
|
|
|
|
|
entry is considered to be in one of three states:</para>
|
|
|
|
|
|
|
|
|
|
<orderedlist>
|
|
|
|
|
<listitem><para>If the 'tries left' counter of an entry is greater than zero the entry is considered to be in
|
|
|
|
|
'indeterminate' state. This means the entry has not completed booting successfully yet, but also hasn't been
|
|
|
|
|
determined not to work.</para></listitem>
|
|
|
|
|
|
|
|
|
|
<listitem><para>If the 'tries left' counter of an entry is zero it is considered to be in 'bad' state. This means
|
|
|
|
|
no further attempts to boot this item will be made (that is, unless all other boot entries are also in 'bad'
|
|
|
|
|
state), as all attempts to boot this entry have not completed successfully.</para></listitem>
|
|
|
|
|
|
|
|
|
|
<listitem><para>If the 'tries left' and 'tries done' counters of an entry are absent it is considered to be in
|
|
|
|
|
'good' state. This means further boot counting for the entry is turned off, as it successfully booted at least
|
|
|
|
|
once. The
|
|
|
|
|
<citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
|
|
|
|
|
service moves the currently booted entry from 'indeterminate' into 'good' state when a boot attempt completed
|
|
|
|
|
successfully.</para></listitem>
|
|
|
|
|
</orderedlist>
|
|
|
|
|
|
|
|
|
|
<para>Generally, when new entries are added to the boot loader, they first start out in 'indeterminate' state,
|
|
|
|
|
i.e. with a 'tries left' counter greater than zero. The boot entry remains in this state until either it managed to
|
|
|
|
|
complete a full boot successfully at least once (in which case it will be in 'good' state) — or the 'tries left'
|
|
|
|
|
counter reaches zero (in which case it will be in 'bad' state).</para>
|
|
|
|
|
|
|
|
|
|
<para>Example: let's say a boot loader entry file <filename>foo.conf</filename> is set up for 3 boot tries. The
|
|
|
|
|
installer will hence create it under the name <filename>foo+3.conf</filename>. On first boot, the boot loader will
|
|
|
|
|
rename it to <filename>foo+2-1.conf</filename>. If that boot does not complete successfully, the boot loader will
|
|
|
|
|
rename it to <filename>foo+1-2.conf</filename> on the following boot. If that fails too, it will finally be renamed
|
|
|
|
|
<filename>foo+0-3.conf</filename> by the boot loader on next boot, after which it will be considered 'bad'. If the
|
|
|
|
|
boot succeeds however the entry file will be renamed to <filename>foo.conf</filename> by the OS, so that it is
|
|
|
|
|
considered 'good' from then on.</para>
|
|
|
|
|
|
|
|
|
|
<para>The boot menu takes the 'tries left' counter into account when sorting the menu entries: entries in 'bad'
|
2022-02-15 17:25:37 +08:00
|
|
|
state are ordered at the beginning of the list, and entries in 'good' or 'indeterminate' at the end. The user can
|
|
|
|
|
freely choose to boot any entry of the menu, including those already marked 'bad'. If the menu entry to boot is
|
|
|
|
|
automatically determined, this means that 'good' or 'indeterminate' entries are generally preferred (as the bottom
|
|
|
|
|
item of the menu is the one booted by default), and 'bad' entries will only be considered if there are no 'good' or
|
2018-06-27 04:11:35 +08:00
|
|
|
'indeterminate' entries left.</para>
|
|
|
|
|
|
|
|
|
|
<para>The <citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry> kernel
|
|
|
|
|
install framework optionally sets the initial 'tries left' counter to the value specified in
|
|
|
|
|
<filename>/etc/kernel/tries</filename> when a boot loader entry is first created.</para>
|
|
|
|
|
</refsect1>
|
|
|
|
|
|
2018-03-11 18:22:09 +08:00
|
|
|
<refsect1>
|
|
|
|
|
<title>See Also</title>
|
|
|
|
|
<para>
|
|
|
|
|
<citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
|
|
|
|
|
<citerefentry><refentrytitle>loader.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
|
2018-06-27 04:11:35 +08:00
|
|
|
<citerefentry><refentrytitle>systemd-bless-boot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
2019-07-22 20:19:33 +08:00
|
|
|
<citerefentry><refentrytitle>systemd-boot-system-token.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
2018-06-27 04:11:35 +08:00
|
|
|
<citerefentry><refentrytitle>kernel-install</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
|
2021-09-21 22:52:24 +08:00
|
|
|
<citerefentry><refentrytitle>systemd-stub</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
|
2018-10-12 20:00:20 +08:00
|
|
|
<ulink url="https://systemd.io/BOOT_LOADER_SPECIFICATION">Boot Loader Specification</ulink>,
|
2018-10-23 22:28:30 +08:00
|
|
|
<ulink url="https://systemd.io/BOOT_LOADER_INTERFACE">Boot Loader Interface</ulink>
|
2018-03-11 18:22:09 +08:00
|
|
|
</para>
|
|
|
|
|
</refsect1>
|
|
|
|
|
</refentry>
|
