xref: /freebsd/stand/defaults/loader.conf.5 (revision 190cef3d52236565eb22e18b33e9e865ec634aa3)
1.\" Copyright (c) 1999 Daniel C. Sobral
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25.\" $FreeBSD$
26.Dd August 28, 2018
27.Dt LOADER.CONF 5
28.Os
29.Sh NAME
30.Nm loader.conf
31.Nd "system bootstrap configuration information"
32.Sh DESCRIPTION
33The file
34.Nm
35contains descriptive information on bootstrapping the system.
36Through
37it you can specify the kernel to be booted, parameters to be passed to
38it, and additional modules to be loaded; and generally set all variables
39described in
40.Xr loader 8 .
41.Pp
42.Sh SYNTAX
43Though
44.Nm Ns 's
45format was defined explicitly to resemble
46.Xr rc.conf 5 ,
47and can be sourced by
48.Xr sh 1 ,
49some settings are treated in a special fashion.
50Also, the
51behavior of some settings is defined by the setting's suffix;
52the prefix identifies which module the setting controls.
53.Pp
54The general parsing rules are:
55.Bl -bullet
56.It
57Spaces and empty lines are ignored.
58.It
59A # sign will mark the remainder of the line as a comment.
60.It
61Only one setting can be present on each line.
62.El
63.Pp
64All settings have the following format:
65.Pp
66.Dl variable="value"
67.Pp
68Unless it belongs to one of the classes of settings that receive special
69treatment, a setting will set the value of a
70.Xr loader 8
71environment variable.
72The settings that receive special
73treatment are listed below.
74Settings beginning with
75.Qq *
76below define the modules to be loaded and
77may have any prefix; the prefix identifies a module.
78All such settings sharing a common
79prefix refer to the same module.
80.Bl -tag -width Ar
81.It Ar exec
82Immediately executes a
83.Xr loader 8
84command.
85This type of setting cannot be processed by programs other
86than
87.Xr loader 8 ,
88so its use should be avoided.
89Multiple instances of it will be processed
90independently.
91.It Ar loader_conf_files
92Defines additional configuration files to be processed right after the
93present file.
94.It Ar kernel
95Name of the kernel to be loaded.
96If no kernel name is set, no additional
97modules will be loaded.
98The name must be a subdirectory of
99.Pa /boot
100that contains a kernel.
101.It Ar kernel_options
102Flags to be passed to the kernel.
103.It Ar vfs.root.mountfrom
104Specify the root partition to mount.
105For example:
106.Pp
107.Dl vfs.root.mountfrom="ufs:/dev/da0s1a"
108.Pp
109.Xr loader 8
110automatically calculates the value of this tunable from
111.Pa /etc/fstab
112from the partition the kernel was loaded from.
113The calculated value might be calculated incorrectly when
114.Pa /etc/fstab
115is not available during
116.Xr loader 8
117startup (as during diskless booting from NFS), or if a different
118device is desired by the user.
119The preferred value can be set in
120.Pa /loader.conf .
121.Pp
122The value can also be overridden from the
123.Xr loader 8
124command line.
125This is useful for system recovery when
126.Pa /etc/fstab
127is damaged, lost, or read from the wrong partition.
128.It Ar password
129Protect boot menu with a password without interrupting
130.Ic autoboot
131process.
132The password should be in clear text format.
133If a password is set, boot menu will not appear until any key is pressed during
134countdown period specified by
135.Va autoboot_delay
136variable or
137.Ic autoboot
138process fails.
139In both cases user should provide specified password to be able to access boot
140menu.
141.It Ar bootlock_password
142Provides a password to be required by check-password before execution is
143allowed to continue.
144The password should be in clear text format.
145If a password is set, the user must provide specified password to boot.
146.It Ar verbose_loading
147If set to
148.Dq YES ,
149module names will be displayed as they are loaded.
150.It Ar *_load
151If set to
152.Dq YES ,
153that module will be loaded.
154If no name is defined (see below), the
155module's name is taken to be the same as the prefix.
156.It Ar *_name
157Defines the name of the module.
158.It Ar *_type
159Defines the module's type.
160If none is given, it defaults to a kld module.
161.It Ar *_flags
162Flags and parameters to be passed to the module.
163.It Ar *_before
164Commands to be executed before the module is loaded.
165Use of this setting
166should be avoided.
167.It Ar *_after
168Commands to be executed after the module is loaded.
169Use of this setting
170should be avoided.
171.It Ar *_error
172Commands to be executed if the loading of a module fails.
173Except for the
174special value
175.Dq abort ,
176which aborts the bootstrap process, use of this setting should be avoided.
177.El
178.Pp
179.Em WARNING:
180developers should never use these suffixes for any kernel environment
181variables (tunables) or conflicts will result.
182.Sh DEFAULT SETTINGS
183Most of
184.Nm Ns 's
185default settings can be ignored.
186The few of them which are important
187or useful are:
188.Bl -tag -width bootfile -offset indent
189.It Va bitmap_load
190.Pq Dq NO
191If set to
192.Dq YES ,
193a bitmap will be loaded to be displayed on screen while booting.
194.It Va bitmap_name
195.Pq Dq Pa /boot/splash.bmp
196Name of the bitmap to be loaded.
197Any other name can be used.
198.It Va comconsole_speed
199.Dq ( 9600
200or the value of the
201.Va BOOT_COMCONSOLE_SPEED
202variable when
203.Xr loader 8
204was compiled).
205Sets the speed of the serial console.
206If the previous boot loader stage specified that a serial console
207is in use then the default speed is determined from the current
208serial port speed setting.
209.It Va console
210.Pq Dq vidconsole
211.Dq comconsole
212selects serial console,
213.Dq vidconsole
214selects the video console,
215.Dq nullconsole
216selects a mute console
217(useful for systems with neither a video console nor a serial port), and
218.Dq spinconsole
219selects the video console which prevents any input and hides all output
220replacing it with
221.Dq spinning
222character (useful for embedded products and such).
223.It Va efi_max_resolution
224Specify the maximum desired resolution for the EFI console.
225The following values are accepted:
226.Bl -column "WidthxHeight"
227.It Sy Value Ta Sy Resolution
228.It 480p Ta 640x480
229.It 720p Ta 1280x720
230.It 1080p Ta 1920x1080
231.It 2160p Ta 3840x2160
232.It 4k Ta 3840x2160
233.It 5k Ta 5120x2880
234.It Va Width Ns x Ns Va Height Ta Va Width Ns x Ns Va Height
235.El
236.It Va kernel
237.Pq Dq kernel
238.It Va kernels
239.Pq Dq kernel kernel.old
240Space or comma separated list of kernels to present in the boot menu.
241.It Va loader_conf_files
242.Pq Dq Pa /boot/loader.conf /boot/loader.conf.local
243.It Va splash_bmp_load
244.Pq Dq NO
245If set to
246.Dq YES ,
247will load the splash screen module, making it possible to display a bmp image
248on the screen while booting.
249.It Va splash_pcx_load
250.Pq Dq NO
251If set to
252.Dq YES ,
253will load the splash screen module, making it possible to display a pcx image
254on the screen while booting.
255.It Va vesa_load
256.Pq Dq NO
257If set to
258.Dq YES ,
259the vesa module will be loaded, enabling bitmaps above VGA resolution to
260be displayed.
261.It Va beastie_disable
262If set to
263.Dq YES ,
264the beastie boot menu will be skipped.
265.It Va loader_logo Pq Dq Li orbbw
266Selects a desired logo in the beastie boot menu.
267Possible values are:
268.Dq Li orbbw ,
269.Dq Li orb ,
270.Dq Li fbsdbw ,
271.Dq Li beastiebw ,
272.Dq Li beastie ,
273and
274.Dq Li none .
275.It Va loader_color
276If set to
277.Dq NO ,
278the beastie boot menu will be displayed without ANSI coloring.
279.It Va entropy_cache_load
280.Pq Dq YES
281If set to
282.Dq NO ,
283the very early
284boot-time entropy file
285will not be loaded.
286See the entropy entries in
287.Xr rc.conf 5 .
288.It Va entropy_cache_name
289.Pq Dq /boot/entropy
290The name of the very early
291boot-time entropy cache file.
292.It Va cpu_microcode_load
293.Pq Dq NO
294If set to
295.Dq YES ,
296the microcode update file specified by
297.Va cpu_microcode_name
298will be loaded and applied very early during boot.
299This provides functionality similar to
300.Xr cpucontrol 8
301but ensures that CPU features enabled by microcode updates can be
302used by the kernel.
303The update will be re-applied automatically when resuming from an
304ACPI sleep state.
305If the update file contains updates for multiple processor models,
306the kernel will search for and extract a matching update.
307Currently this setting is supported only on Intel
308.Dv i386
309and
310.Dv amd64
311processors.
312It has no effect on other processor types.
313.It Va cpu_microcode_name
314A path to a microcode update file.
315.El
316.Sh OTHER SETTINGS
317Other settings that may be used in
318.Nm
319that have no default value:
320.Bl -tag -width bootfile -offset indent
321.It Va fdt_overlays
322Specifies a comma-delimited list of FDT overlays to apply.
323.Pa /boot/dtb/overlays
324is created by default for overlays to be placed in.
325.It Va kernels_autodetect
326If set to
327.Dq YES ,
328attempt to auto-detect kernels installed in
329.Pa /boot .
330This is an option specific to the Lua-based loader.
331It is not available in the default Forth-based loader.
332.El
333.Sh FILES
334.Bl -tag -width /boot/defaults/loader.conf -compact
335.It Pa /boot/defaults/loader.conf
336default settings -- do not change this file.
337.It Pa /boot/loader.conf
338user defined settings.
339.It Pa /boot/loader.conf.local
340machine-specific settings for sites with a common loader.conf.
341.El
342.Sh SEE ALSO
343.Xr rc.conf 5 ,
344.Xr boot 8 ,
345.Xr cpucontrol 8 ,
346.Xr loader 8 ,
347.Xr loader.4th 8
348.Sh HISTORY
349The file
350.Nm
351first appeared in
352.Fx 3.2 .
353.Sh AUTHORS
354This manual page was written by
355.An Daniel C. Sobral Aq dcs@FreeBSD.org .
356.Sh BUGS
357The
358.Xr loader 8
359stops reading
360.Nm
361when it encounters a syntax error, so any options which are vital for
362booting a particular system (i.e.\&
363.Dq Va hw.ata.ata_dma Ns "=0" )
364should precede any experimental additions to
365.Nm .
366