LOADER.CONF(5) FreeBSD File Formats Manual LOADER.CONF(5)
NAME
loader.conf - system bootstrap configuration information
DESCRIPTION
The file loader.conf contains descriptive information on bootstrapping
the system. Through it you can specify the kernel to be booted,
parameters to be passed to it, and additional modules to be loaded; and
generally set all variables described in loader(8).
SYNTAX
Though loader.conf's format was defined explicitly to resemble
rc.conf(5), and can be sourced by sh(1), some settings are treated in a
special fashion. Also, the behavior of some settings is defined by the
setting's suffix; the prefix identifies which module the setting
controls.
The general parsing rules are:
• Spaces and empty lines are ignored.
• A # sign will mark the remainder of the line as a comment.
• Only one setting can be present on each line.
All settings have the following format:
variable="value"
Unless it belongs to one of the classes of settings that receive special
treatment, a setting will set the value of a loader(8) environment
variable. The settings that receive special treatment are listed below.
Settings beginning with "*" below define the modules to be loaded and may
have any prefix; the prefix identifies a module. All such settings
sharing a common prefix refer to the same module.
autoboot_delay
Delay in seconds before automatically booting. A user with
console access will be able to interrupt the autoboot
process and escape into the interactive mode by pressing a
key on the console during this delay.
If set to "NO", no autoboot is automatically attempted
after processing /boot/loader.rc, though explicit
autoboot's are processed normally, using a 10 second delay.
If set to "0", no delay is inserted, but any keys pressed
while the kernel and modules are loaded will enter
interactive mode.
If set to "-1", no delay will be inserted and loader.conf
starts interactive mode only if autoboot has failed. In
combination with the beastie_disable option, this option
prevents users with console access from being able to
interrupt the autoboot process and escape to the loader
prompt. To use the autoboot_delay option in this manner,
beastie_disable must be set to "YES".
exec Immediately executes a loader(8) command. This type of
setting cannot be processed by programs other than
loader(8), so its use should be avoided. Multiple
instances of it will be processed independently.
loader_conf_dirs
Space separated list of directories to process for
configuration files. The lua-based loader will process
files with a ".conf" suffix that are placed in these
directories.
loader_conf_files
Defines additional configuration files to be processed
right after the present file. loader_conf_files should be
treated as write-only. One cannot depend on any value
remaining in the loader environment or carried over into
the kernel environment.
kernel Name of the kernel to be loaded. If no kernel name is set,
no additional modules will be loaded. The name must be a
subdirectory of /boot that contains a kernel.
kernel_options
Flags to be passed to the kernel.
vfs.root.mountfrom
Specify the root partition to mount. For example:
vfs.root.mountfrom="ufs:/dev/da0s1a"
loader(8) automatically calculates the value of this
tunable from /etc/fstab from the partition the kernel was
loaded from. The calculated value might be calculated
incorrectly when /etc/fstab is not available during
loader(8) startup (as during diskless booting from NFS), or
if a different device is desired by the user. The
preferred value can be set in /loader.conf.
The value can also be overridden from the loader(8) command
line. This is useful for system recovery when /etc/fstab
is damaged, lost, or read from the wrong partition.
password Protect boot menu with a password without interrupting
autoboot process. The password should be in clear text
format. If a password is set, boot menu will not appear
until any key is pressed during countdown period specified
by autoboot_delay variable or autoboot process fails. In
both cases user should provide specified password to be
able to access boot menu.
bootlock_password
Provides a password to be required by check-password before
execution is allowed to continue. The password should be
in clear text format. If a password is set, the user must
provide specified password to boot.
verbose_loading
If set to "YES", module names will be displayed as they are
loaded.
module_blacklist
Blacklist of modules. Modules specified in the blacklist
may not be loaded automatically with a *_load directive,
but they may be loaded directly at the loader(8) prompt.
Blacklisted modules may still be loaded indirectly as
dependencies of other modules.
*_load If set to "YES", that module will be loaded. If no name is
defined (see below), the module's name is taken to be the
same as the prefix.
*_name Defines the name of the module.
*_type Defines the module's type. If none is given, it defaults
to a kld module.
*_flags Flags and parameters to be passed to the module.
*_before Commands to be executed before the module is loaded. Use
of this setting should be avoided.
*_after Commands to be executed after the module is loaded. Use of
this setting should be avoided.
*_error Commands to be executed if the loading of a module fails.
Except for the special value "abort", which aborts the
bootstrap process, use of this setting should be avoided.
WARNING: developers should never use these suffixes for any kernel
environment variables (tunables) or conflicts will result.
DEFAULT SETTINGS
Most of loader.conf's default settings can be ignored. The few of them
which are important or useful are:
bitmap_load
("NO") If set to "YES", a bitmap will be loaded to be
displayed on screen while booting.
bitmap_name
("/boot/splash.bmp") Name of the bitmap to be loaded.
Any other name can be used.
comconsole_speed
("9600" or the value of the BOOT_COMCONSOLE_SPEED
variable when loader(8) was compiled). Sets the speed of
the serial console. If the previous boot loader stage
specified that a serial console is in use then the
default speed is determined from the current serial port
speed setting.
console ("vidconsole") "comconsole" selects serial console,
"vidconsole" selects the video console, "efi" selects the
EFI console, "nullconsole" selects a mute console (useful
for systems with neither a video console nor a serial
port), and "spinconsole" selects the video console which
prevents any input and hides all output replacing it with
"spinning" character (useful for embedded products and
such).
screen.font
Set font size for framebuffer mode. Default font size is
selected based on screen resolution, to achieve terminal
dimensions 80x24.
screen.textmode
Value "0" will trigger BIOS loader to switch to use VESA
BIOS Extension (VBE) frame buffer mode for console. The
same effect can be achieved by setting
vbe_max_resolution.
Value "1" will force BIOS loader to use VGA text mode.
If vbe_max_resolution is not set, the loader will try to
set screen resolution based on EDID information. If EDID
is not available, the default resolution is 800x600 (if
available).
screen.height
screen.width
screen.depth
screen.height, screen.width, screen.depth are set by
loader when loader is using framebuffer mode to draw the
screen.
efi_max_resolution
vbe_max_resolution
Specify the maximum desired resolution for the EFI or VBE
framebuffer console. The following values are accepted:
Value Resolution
480p 640x480
720p 1280x720
1080p 1920x1080
2160p 3840x2160
4k 3840x2160
5k 5120x2880
WidthxHeight WidthxHeight
kernel ("kernel")
kernels ("kernel kernel.old") Space or comma separated list of
kernels to present in the boot menu.
loader_conf_files
("/boot/loader.conf /boot/loader.conf.local")
loader_conf_dirs
("/boot/loader.conf.d")
splash_bmp_load
("NO") If set to "YES", will load the splash screen
module, making it possible to display a bmp image on the
screen while booting.
splash_pcx_load
("NO") If set to "YES", will load the splash screen
module, making it possible to display a pcx image on the
screen while booting.
vesa_load
("NO") If set to "YES", the vesa module will be loaded,
enabling bitmaps above VGA resolution to be displayed.
beastie_disable
If set to "YES", the beastie boot menu will be skipped.
loader_logo ("orbbw")
Selects a desired logo in the beastie boot menu.
Possible values are: "orbbw", "orb", "fbsdbw",
"beastiebw", "beastie", and "none".
loader_color
If set to "NO", the beastie boot menu will be displayed
without ANSI coloring.
entropy_cache_load
("YES") If set to "NO", the very early boot-time entropy
file will not be loaded. See the entropy entries in
rc.conf(5).
entropy_cache_name
("/boot/entropy") The name of the very early boot-time
entropy cache file.
cpu_microcode_load
("NO") If set to "YES", the microcode update file
specified by cpu_microcode_name will be loaded and
applied very early during boot. This provides
functionality similar to cpucontrol(8) but ensures that
CPU features enabled by microcode updates can be used by
the kernel. The update will be re-applied automatically
when resuming from an ACPI sleep state. If the update
file contains updates for multiple processor models, the
kernel will search for and extract a matching update.
Currently this setting is supported only on Intel i386
and amd64 processors. It has no effect on other
processor types.
cpu_microcode_name
A path to a microcode update file.
OTHER SETTINGS
Other settings that may be used in loader.conf that have no default
value:
fdt_overlays
Specifies a comma-delimited list of FDT overlays to
apply. /boot/dtb/overlays is created by default for
overlays to be placed in.
kernels_autodetect
If set to "YES", attempt to auto-detect kernels installed
in /boot. This is an option specific to the Lua-based
loader. It is not available in the default Forth-based
loader.
FILES
/boot/defaults/loader.conf default settings -- do not change this file.
/boot/loader.conf user defined settings.
/boot/loader.conf.local machine-specific settings for sites with a
common loader.conf.
SEE ALSO
rc.conf(5), boot(8), cpucontrol(8), loader(8), loader.4th(8)
HISTORY
The file loader.conf first appeared in FreeBSD 3.2.
AUTHORS
This manual page was written by Daniel C. Sobral <dcs@FreeBSD.org>.
BUGS
The loader(8) stops reading loader.conf when it encounters a syntax
error, so any options which are vital for booting a particular system
(i.e., "hw.ata.ata_dma=0") should precede any experimental additions to
loader.conf.
FreeBSD 13.1-RELEASE-p6 July 31, 2021 FreeBSD 13.1-RELEASE-p6
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