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LOADER.CONF(5) 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 fash- ion. Also, the behavior of some settings is defined by the setting's suf- fix; 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 vari- able. The settings that receive special treatment are listed below. Set- tings 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 interac- tive mode. If set to "-1", no delay will be inserted and loader.conf starts interactive mode only if autoboot has failed. In com- bination with the beastie_disable option, this option pre- vents 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". print_delay Add a delay in microseconds after printing each line. De- fault "0". boot_* See list in loader.efi(8) since those flags apply to all boot loaders. boot_verbose Set to "yes" to get the same effect as boot -v or booting verbose from the loader menu. See the kern.msgbufsize tune- able to ensure enough space for the increased number of mes- sages. exec Immediately executes a loader(8) command. This type of set- ting 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 configura- tion files. The lua-based loader will process files with a ".conf" suffix that are placed in these directories. Files found here are processed after the ones listed in loader_conf_files but before the ones found in local_loader_conf_files. 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 envi- ronment. local_loader_conf_files Space separated list of additional configuration files to be processed at last, i.e., after loader_conf_files and loader_conf_dirs are processed. product_vars When set, must be a space separated list of environment vari- able names to walk through to guess product information. The order matters as reading a config file override the previ- ously defined values. Undefined variables are silently ig- nored. When product information can be guessed, for each product in- formation found, append /boot/loader.conf.d/PRODUCT to loader_conf_dirs. It can be typically used as follow: smbios.system.planar.maker="PLANAR_MAKER" smbios.system.planar.product="PLANAR_PRODUCT" smbios.system.product="PRODUCT" uboot.m_product="M_PRODUCT" product_vars="smbios.system.planar.maker smbios.system.planar.product smbios.system.product uboot.m_product" to read files found in the following directories, in that or- der: * /boot/loader.conf.d/PLANAR_MAKER * /boot/loader.conf.d/PLANAR_PRODUCT * /boot/loader.conf.d/PRODUCT * /boot/loader.conf.d/M_PRODUCT 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 for- mat. 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 pro- vide 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 boot- strap process, use of this setting should be avoided. WARNING: developers should never use these suffixes for any kernel environ- ment 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: local_loader_conf_files ("/boot/loader.conf.local") Ensure loader.conf.local can always be used to override settings from files found in loader_conf_files and loader_conf_dirs. bitmap_load ("NO") If set to "YES", a bitmap will be loaded to be dis- played on screen while booting. bitmap_name ("/boot/splash.bmp") Name of the bitmap to be loaded. Any other name can be used. comconsole_speed ("115200" or the value of the BOOT_COMCONSOLE_SPEED vari- able when loader(8) was compiled). Sets the speed of the serial console. If the previous boot loader stage speci- fied 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). This setting is for the loader(8) only and does not set the kernel output. screen.font Set font size for framebuffer mode. The default font size is selected based on screen resolution. Note that the ter- minal's size may vary. 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 1440p 2560x1440 2160p 3840x2160 4k 3840x2160 5k 5120x2880 WidthxHeight WidthxHeight kernel ("kernel") kernels ("kernel kernel.old") Space or comma separated list of ker- nels 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, en- abling bitmaps above VGA resolution to be displayed. beastie_disable If set to "YES", the beastie boot menu will be skipped. loader_autoboot_show ("YES") If set to "NO", the autoboot menu will not be displayed loader_gfx If set to "NO", the ASCII art version of the brand and logo will be used even if graphical versions are available. Ad- ditionally, the menu frame will be drawn with ASCII art as well. loader_logo ("orbbw") Selects a desired logo in the beastie boot menu. Possible values are: "orbbw", "orb", "fbsdbw", "beastiebw", "beastie", and "none". loader_menu If set to "NONE", the menu will not be displayed 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 en- tropy 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 cpu- control(8) but ensures that CPU features enabled by microc- ode 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.lua User defined settings written in lua. /boot/loader.conf.d/*.conf User defined settings split in separate files. /boot/loader.conf.d/*.lua User defined settings written in lua and split in separate files. /boot/loader.conf.local Machine-specific settings for sites with a com- mon loader.conf. Allow to override settings de- fined in other files. SEE ALSO kenv(1), loader.conf.lua(5), 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 15.0 September 2, 2025 LOADER.CONF(5)
NAME | DESCRIPTION | SYNTAX | DEFAULT SETTINGS | OTHER SETTINGS | FILES | SEE ALSO | HISTORY | AUTHORS | BUGS
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