Training courses

Kernel and Embedded Linux

Bootlin training courses

Embedded Linux, kernel,
Yocto Project, Buildroot, real-time,
graphics, boot time, debugging...

Bootlin logo

Elixir Cross Referencer

# This is loader.conf - a file full of useful variables that you can
# set to change the default load behavior of your system. You should
# not edit this file!  Put any overrides into one of the
# loader_conf_files instead and you will be able to update these
# defaults later without spamming your local configuration information.
#
# All arguments must be in double quotes.
#
# $FreeBSD$

###  Basic configuration options  ############################
exec="echo Loading /boot/defaults/loader.conf"

kernel="kernel"		# /boot sub-directory containing kernel and modules
bootfile="kernel"	# Kernel name (possibly absolute path)
kernel_options=""	# Flags to be passed to the kernel
loader_conf_files="/boot/device.hints /boot/loader.conf /boot/loader.conf.local"
nextboot_conf="/boot/nextboot.conf"
verbose_loading="NO"		# Set to YES for verbose loader output

###  Splash screen configuration  ############################
splash_bmp_load="NO"		# Set this to YES for bmp splash screen!
splash_pcx_load="NO"		# Set this to YES for pcx splash screen!
splash_txt_load="NO"		# Set this to YES for TheDraw splash screen!
vesa_load="NO"			# Set this to YES to load the vesa module
bitmap_load="NO"		# Set this to YES if you want splash screen!
bitmap_name="splash.bmp"	# Set this to the name of the file
bitmap_type="splash_image_data" # and place it on the module_path

###  Screen saver modules  ###################################
# This is best done in rc.conf
screensave_load="NO"		# Set to YES to load a screensaver module
screensave_name="green_saver"	# Set to the name of the screensaver module

###  Early hostid configuration ############################
hostuuid_load="YES"
hostuuid_name="/etc/hostid"
hostuuid_type="hostuuid"

###  Random number generator configuration  ##################
# See rc.conf(5). The entropy_boot_file config variable must agree with the
# settings below.
entropy_cache_load="YES"		# Set this to NO to disable loading
					# entropy at boot time
entropy_cache_name="/boot/entropy"	# Set this to the name of the file
entropy_cache_type="boot_entropy_cache"	# Required for the kernel to find
					# the boot-time entropy cache. This
					# must not change value even if the
					# _name above does change!

###  RAM Blacklist configuration  ############################
ram_blacklist_load="NO"			# Set this to YES to load a file
					# containing a list of addresses to
					# exclude from the running system.
ram_blacklist_name="/boot/blacklist.txt" # Set this to the name of the file
ram_blacklist_type="ram_blacklist"	# Required for the kernel to find
					# the blacklist module

###  Microcode loading configuration  ########################
cpu_microcode_load="NO"			# Set this to YES to load and apply a
					# microcode update file during boot.
cpu_microcode_name="/boot/firmware/ucode.bin" # Set this to the microcode
					      # update file path.
cpu_microcode_type="cpu_microcode"	# Required for the kernel to find
					# the microcode update file.

###  ACPI settings  ##########################################
acpi_dsdt_load="NO"		# DSDT Overriding
acpi_dsdt_type="acpi_dsdt"	# Don't change this
acpi_dsdt_name="/boot/acpi_dsdt.aml"
				# Override DSDT in BIOS by this file
acpi_video_load="NO"		# Load the ACPI video extension driver

###  Audit settings  #########################################
audit_event_load="NO"		# Preload audit_event config
audit_event_name="/etc/security/audit_event"
audit_event_type="etc_security_audit_event"

###  Initial memory disk settings  ###########################
#mdroot_load="YES"		# The "mdroot" prefix is arbitrary.
#mdroot_type="md_image"		# Create md(4) disk at boot.
#mdroot_name="/boot/root.img"	# Path to a file containing the image.
#rootdev="ufs:/dev/md0"		# Set the root filesystem to md(4) device.

###  Loader settings  ########################################
#loader_delay="3"		# Delay in seconds before loading anything.
				# Default is unset and disabled (no delay).
#autoboot_delay="10"		# Delay in seconds before autobooting,
				# -1 for no user interrupts, NO to disable
#password=""			# Prevent changes to boot options
#bootlock_password=""		# Prevent booting (see check-password.4th(8))
#geom_eli_passphrase_prompt="NO" # Prompt for geli(8) passphrase to mount root
bootenv_autolist="YES"		# Auto populate the list of ZFS Boot Environments
#beastie_disable="NO"		# Turn the beastie boot menu on and off
efi_max_resolution="1x1"	# Set the max resolution for EFI loader to use:
				# 480p, 720p, 1080p, 2160p/4k, 5k, or specify
				# WidthxHeight (e.g. 1920x1080)
#kernels="kernel kernel.old"	# Kernels to display in the boot menu
kernels_autodetect="YES"	# Auto-detect kernel directories in /boot
#loader_logo="orbbw"		# Desired logo: orbbw, orb, fbsdbw, beastiebw, beastie, none
#comconsole_speed="9600"	# Set the current serial console speed
#console="vidconsole"		# A comma separated list of console(s)
#currdev="disk1s1a"		# Set the current device
module_path="/boot/modules;/boot/dtb;/boot/dtb/overlays"	# Set the module search path
module_blacklist="drm drm2 radeonkms i915kms amdgpu"	# Loader module blacklist
#prompt="\\${interpret}"	# Set the command prompt
#root_disk_unit="0"		# Force the root disk unit number
#rootdev="disk1s1a"		# Set the root filesystem
#dumpdev="disk1s1b"		# Set a dump device early in the boot process
#tftp.blksize="1428"		# Set the RFC 2348 TFTP block size.
				# If the TFTP server does not support RFC 2348,
				# the block size is set to 512. Valid: (8,9007)
#twiddle_divisor="1"		# >1 means slow down the progress indicator.

###  Kernel settings  ########################################
# The following boot_ variables are enabled by setting them to any value.
# Their presence in the kernel environment (see kenv(1)) has the same
# effect as setting the given boot flag (see boot(8)).
#boot_askname=""	# -a: Prompt the user for the name of the root device
#boot_cdrom=""		# -C: Attempt to mount root file system from CD-ROM
#boot_ddb=""		# -d: Instructs the kernel to start in the DDB debugger
#boot_dfltroot=""	# -r: Use the statically configured root file system
#boot_gdb=""		# -g: Selects gdb-remote mode for the kernel debugger
#boot_multicons=""	# -D: Use multiple consoles
#boot_mute=""		# -m: Mute the console
#boot_pause=""		# -p: Pause after each line during device probing
#boot_serial=""		# -h: Use serial console
#boot_single=""		# -s: Start system in single-user mode
#boot_verbose=""	# -v: Causes extra debugging information to be printed
#init_path="/sbin/init:/sbin/oinit:/sbin/init.bak:/rescue/init"
			# Sets the list of init candidates
#init_shell="/bin/sh"	# The shell binary used by init(8).
#init_script=""		# Initial script to run by init(8) before chrooting.
#init_chroot=""		# Directory for init(8) to chroot into.

###  Kernel tunables  ########################################
#hw.physmem="1G"		# Limit physical memory. See loader(8)
#kern.dfldsiz=""		# Set the initial data size limit
#kern.dflssiz=""		# Set the initial stack size limit
#kern.hz="100"			# Set the kernel interval timer rate
#kern.maxbcache=""		# Set the max buffer cache KVA storage
#kern.maxdsiz=""		# Set the max data size
#kern.maxfiles=""		# Set the sys. wide open files limit
#kern.maxproc=""		# Set the maximum # of processes
#kern.maxssiz=""		# Set the max stack size
#kern.maxswzone=""		# Set the max swmeta KVA storage
#kern.maxtsiz=""		# Set the max text size
#kern.maxusers="32"		# Set size of various static tables
#kern.msgbufsize="65536"	# Set size of kernel message buffer
#kern.nbuf=""			# Set the number of buffer headers
#kern.ncallout=""		# Set the maximum # of timer events
#kern.ngroups="1023"		# Set the maximum # of supplemental groups
#kern.sgrowsiz=""		# Set the amount to grow stack
#kern.cam.boot_delay="10000"	# Delay (in ms) of root mount for CAM bus
				# registration, useful for USB sticks as root
#kern.cam.scsi_delay="2000"	# Delay (in ms) before probing SCSI
#kern.ipc.maxsockets=""		# Set the maximum number of sockets available
#kern.ipc.nmbclusters=""	# Set the number of mbuf clusters
#kern.ipc.nsfbufs=""		# Set the number of sendfile(2) bufs
#net.inet.tcp.tcbhashsize=""	# Set the value of TCBHASHSIZE
#vfs.root.mountfrom=""		# Specify root partition
#vm.kmem_size=""		# Sets the size of kernel memory (bytes)
#debug.kdb.break_to_debugger="0" # Allow console to break into debugger.
#debug.ktr.cpumask="0xf"	# Bitmask of CPUs to enable KTR on
#debug.ktr.mask="0x1200"	# Bitmask of KTR events to enable
#debug.ktr.verbose="1"		# Enable console dump of KTR events

###  Module loading syntax example  ##########################
#module_load="YES"		# loads module "module"
#module_name="realname"		# uses "realname" instead of "module"
#module_type="type"		# passes "-t type" to load
#module_flags="flags"		# passes "flags" to the module
#module_before="cmd"		# executes "cmd" before loading the module
#module_after="cmd"		# executes "cmd" after loading the module
#module_error="cmd"		# executes "cmd" if load fails