xref: /netbsd-src/share/man/man4/options.4 (revision 16dce51364ebe8aeafbae46bc5aa167b8115bc45) 
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3.\" Copyright (c) 1996
4.\" 	Perry E. Metzger.  All rights reserved.
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32.\"
33.Dd April 5, 2018
34.Dt OPTIONS 4
35.Os
36.Sh NAME
37.Nm options
38.Nd Miscellaneous kernel configuration options
39.Sh SYNOPSIS
40.Cd cinclude ...
41.Cd config ...
42.Cd [no] file-system ...
43.Cd ident ...
44.Cd include ...
45.Cd [no] makeoptions ...
46.Cd maxusers ...
47.Cd [no] options ...
48.Cd [no] pseudo-device ...
49.Sh DESCRIPTION
50This manual page describes a number of miscellaneous kernel
51configuration options that may be specified in a kernel config
52file.
53See
54.Xr config 1
55and
56.Xr config 5
57for information on how to configure and build kernels.
58.Pp
59The
60.Ar no
61form removes a previously specified option.
62.Ss Keywords
63The following keywords are recognized in a kernel configuration file:
64.Bl -ohang
65.It Sy cinclude Qq Ar filename
66Conditionally includes another kernel configuration file whose name is
67.Ar filename ,
68which may be double-quoted and may be an explicit path or relative to
69the kernel source directory.
70Failure to open the named file is ignored.
71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \
72Oo dumps on Ar dumpdev Oc
73Defines a configuration whose kernel executable is named
74.Ar exec_name ,
75normally
76.Dq netbsd ,
77with its root file system of type
78.Ar fstype
79on the device
80.Ar rootdev ,
81and optionally specifying the location of kernel core dumps on the device
82.Ar dumpdev .
83.Ar dev
84or
85.Ar dumpdev
86and
87.Ar fstype
88may be specified as
89.Dq \&? ,
90which is a wild card.
91The root
92.Ar fstype
93and
94.Ar dumpdev
95are optional and assumed to be wild carded if they are not specified.
96.It Ar device_instance No at Ar attachment \
97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc
98Define an instance of the device driver
99.Ar device_instance
100that attaches to the bus or device named
101.Ar attachment .
102An
103.Ar attachment
104may require additional information on where the device can be found, such
105as an address, channel, function, offset, and/or slot, referred to as
106.Ar locators ,
107whose
108.Ar value
109often may be a wild card,
110.Dq \&? .
111Some device drivers have one or more
112.Ar flags
113that can be adjusted to affect the way they operate.
114.It Sy file-system Ar fs_name Op , Ar fs_name Op ...
115Include support for the file-system
116.Ar fs_name .
117.It Sy ident Qq Ar string
118Sets the kernel identification string to
119.Ar string .
120.It Sy include Qq Ar filename
121Functions the same as
122.Ar cinclude ,
123except failure to open
124.Ar filename
125produces a fatal error.
126.It Sy options Ar option_name Op , Ar option_name=value Op ...
127Specifies (or sets) the option, or comma-separated list of options,
128.Ar option_name .
129Some options expect to be assigned a value, which may be an integer,
130a double-quoted word, a bare word, or an empty string
131.Pq Qq .
132Note that those are eventually handled by the C compiler, so the rules
133of that language apply.
134.Pp
135.Em Note :
136Options that are not defined by device definition files are passed to
137the compile process as
138.Fl D
139flags to the C compiler.
140.It Sy makeoptions Ar name=value
141Defines a
142.Xr make 1
143macro
144.Ar name
145with the value
146.Ar value
147in the kernel Makefile.
148.It Sy maxusers Ar integer
149Set the maxusers variable in the kernel.
150.It Sy no Ar keyword Ar name Op Ar arguments Op ...
151For the
152.Xr config 1
153.Ar keywords
154file-system, makeoptions, options, and pseudo-device,
155.Ar no
156removes the file-system, makeoption, options, or pseudo-device,
157.Ar name .
158This is useful when a kernel configuration file includes another which
159has undesired options.
160.Pp
161For example, a local configuration file that wanted the kitchen sink, but
162not COMPAT_09 or bridging, might be:
163.Bd -literal -offset indent
164include "arch/i386/conf/GENERIC"
165no options COMPAT_09
166no pseudo-device bridge
167.Ed
168.It Sy pseudo-device Ar name Op Ar N
169Includes support for the pseudo-device
170.Ar name .
171Some pseudo-devices can have multiple or
172.Ar N
173instances.
174.El
175.Ss Compatibility Options
176Note that compatibility options for older
177.Nx
178releases includes support for newer releases as well.
179This means that typically only one of these is necessary, with the
180.Cd COMPAT_09
181option enabling all
182.Nx
183compatibility.
184This does not include the
185.Cd COMPAT_43
186or
187.Cd COMPAT_44
188options.
189.Bl -ohang
190.It Cd options COMPAT_09
191Enable binary compatibility with
192.Nx 0.9 .
193This enables support for
19416-bit user, group, and process IDs (following revisions support
19532-bit identifiers).
196It also allows the use of the deprecated
197.Xr getdomainname 3 ,
198.Xr setdomainname 3 ,
199and
200.Xr uname 3
201syscalls.
202This option also allows using numeric file system identifiers rather
203than strings.
204Post
205.Nx 0.9
206versions use string identifiers.
207.It Cd options COMPAT_10
208Enable binary compatibility with
209.Nx 1.0 .
210This option allows the use of the file system name of
211.Dq ufs
212as an alias for
213.Dq ffs .
214The name
215.Dq ffs
216should be used post 1.0 in
217.Pa /etc/fstab
218and other files.
219It also adds old syscalls for the
220.At V
221shared memory interface.
222This was changed post 1.0 to work on 64-bit architectures.
223This option also enables
224.Dq sgtty
225compatibility, without which programs using the old interface produce
226an
227.Dq inappropriate ioctl
228error, and
229.Pa /dev/io
230only works when this option is set in the kernel,
231see
232.Xr io 4
233on ports that support it.
234.It Cd options COMPAT_11
235Enable binary compatibility with
236.Nx 1.1 .
237This allows binaries running on the i386 port to gain direct access to
238the io ports by opening
239.Pa /dev/io
240read/write.
241This functionality was replaced by
242.Xr i386_iopl 2
243post 1.1.
244On the Atari port, the location of the disk label was moved after 1.1.
245When the
246.Em COMPAT_11
247option is set, the kernel will read (pre) 1.1 style disk labels as a
248last resort.
249When a disk label is re-written, the old style label will be replaced
250with a post 1.1 style label.
251This also enables the
252.Em EXEC_ELF_NOTELESS
253option.
254.It Cd options COMPAT_12
255Enable binary compatibility with
256.Nx 1.2 .
257This allows the use of old syscalls for
258.Fn reboot
259and
260.Fn swapon .
261The syscall numbers were changed post 1.2 to add functionality to the
262.Xr reboot 2
263syscall, and the new
264.Xr swapctl 2
265interface was introduced.
266This also enables the
267.Em EXEC_ELF_NOTELESS
268option.
269.It Cd options COMPAT_13
270Enable binary compatibility with
271.Nx 1.3 .
272This allows the use of old syscalls for
273.Fn sigaltstack ,
274and also enables the old
275.Xr swapctl 2
276command
277.Dv SWAP_STATS
278(now called
279.Dv SWAP_OSTATS ) ,
280which does not include the
281.Fa se_path
282member of
283.Va struct swapent .
284.It Cd options COMPAT_14
285Enable binary compatibility with
286.Nx 1.4 .
287This allows some old
288.Xr ioctl 2
289on
290.Xr wscons 4
291to be performed, and allows the
292.Dv NFSSVC_BIOD
293mode of the
294.Xr nfssvc 2
295system call to be used for compatibility with the deprecated nfsiod program.
296.It Cd options COMPAT_15
297Enable binary compatibility with
298.Nx 1.5 .
299Since there were no API changes from
300.Nx 1.5
301and
302.Nx 1.6 ,
303this option does nothing.
304.It Cd options COMPAT_16
305Enable binary compatibility with
306.Nx 1.6 .
307This allows the use of old signal trampoline code which has been deprecated
308with the addition of
309.Xr siginfo 2 .
310.It Cd options COMPAT_20
311Enable binary compatibility with
312.Nx 2.0 .
313This allows the use of old syscalls for
314.Fn statfs ,
315.Fn fstatfs ,
316.Fn getfsstat
317and
318.Fn fhstatfs ,
319which have been deprecated with the addition of the
320.Xr statvfs 2 ,
321.Xr fstatvfs 2 ,
322.Xr getvfsstat 2
323and
324.Xr fhstatvfs 2
325system calls.
326.It Cd options COMPAT_30
327Enable binary compatibility with
328.Nx 3.0 .
329See
330.Xr compat_30 8
331for details about the changes made after the
332.Nx 3.0
333release.
334.It Cd options COMPAT_40
335Enable binary compatibility with
336.Nx 4.0 .
337This allows the use of old
338.Xr ptrace 2
339calls for the SH3 platform.
340It also enables the old
341.Xr mount 2
342system call that did not include the data length parameter.
343The power_event_t structure's pev_switch is filled in.
344.It Cd options COMPAT_43
345Enables compatibility with
346.Bx 4.3 .
347This adds an old syscall for
348.Xr lseek 2 .
349It also adds the ioctls for
350.Dv TIOCGETP
351and
352.Dv TIOCSETP .
353The return values for
354.Xr getpid 2 ,
355.Xr getgid 2 ,
356and
357.Xr getuid 2
358syscalls are modified as well, to return the parent's PID and
359UID as well as the current process's.
360It also enables the deprecated
361.Dv NTTYDISC
362terminal line discipline.
363It also provides backwards compatibility with
364.Dq old
365SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including
366binary compatibility with code written before the introduction of the
367sa_len field in sockaddrs.
368It also enables
369support for some older pre
370.Bx 4.4
371socket calls.
372.It Cd options COMPAT_50
373Enable binary compatibility with
374.Nx 5.0 .
375This enables support for the old
376.Ft time_t
377and
378.Ft dev_t
379types as 32 bit, and all the associated kernel interface changes.
380It also enables old
381.Xr gpio 4
382and
383.Xr rnd 4
384interfaces.
385.It Cd options COMPAT_60
386Enable binary compatibility with
387.Nx 6.0 .
388This provides old
389.Xr ccd 4
390interfaces, enables support for old
391.Xr cpuctl 8
392microcode interfaces, and support for the old
393.Ft ptmget
394structure.
395.It Cd options COMPAT_70
396Enable binary compatibility with
397.Nx 7.0 .
398This provides support for old
399.Xr route 4
400interfaces.
401.It Cd options COMPAT_BSDPTY
402This option is currently on by default and enables the pty multiplexer
403.Xr ptm 4
404and
405.Xr ptmx 4
406to find and use ptys named
407.Pa /dev/ptyXX
408(master) and
409.Pa /dev/ttyXX
410(slave).
411Eventually this option will become optional as ptyfs based pseudo-ttys become
412the default, see
413.Xr mount_ptyfs 8 .
414.It Cd options COMPAT_SVR4
415On those architectures that support it, this enables binary
416compatibility with
417.At V.4
418applications built for the same architecture.
419This currently includes the m68k and sparc ports.
420.It Cd options COMPAT_LINUX
421On those architectures that support it, this enables binary
422compatibility with Linux ELF and
423.Xr a.out 5
424applications built for the same architecture.
425This currently includes the alpha, arm, i386, m68k, mips, powerpc and
426x86_64 ports.
427.It Cd options COMPAT_LINUX32
428On those 64 bit architectures that support it, this enables binary
429compatibility with 32 bit Linux binaries.
430For now this is limited to running i386 ELF Linux binaries on amd64.
431.It Cd options COMPAT_SUNOS
432On those architectures that support it, this enables binary
433compatibility with SunOS 4.1 applications built for the same architecture.
434This currently includes the sparc, sparc64 and most or all m68k ports.
435Note that the sparc64 requires the
436.Em COMPAT_NETBSD32
437option for 64-bit kernels, in addition to this option.
438.It Cd options COMPAT_ULTRIX
439On those architectures that support it, this enables binary
440compatibility with ULTRIX applications built for the same architecture.
441This currently is limited to the pmax.
442The functionality of this option is unknown.
443.It Cd options COMPAT_FREEBSD
444On those architectures that support it, this enables binary
445compatibility with
446.Fx
447applications built for the same architecture.
448At the moment this is limited to the i386 port.
449.It Cd options COMPAT_IBCS2
450On those architectures that support it, this enables binary
451compatibility with iBCS2 or SVR3 applications built for the same architecture.
452This is currently limited to the i386 and vax ports.
453.It Cd options COMPAT_OSF1
454On those architectures that support it, this enables binary
455compatibility with Digital
456.Ux
457(formerly OSF/1)
458applications built for the same architecture.
459This is currently limited to the alpha port.
460.It Cd options COMPAT_NOMID
461Enable compatibility with
462.Xr a.out 5
463executables that lack a machine ID.
464This includes
465.Nx 0.8 Ns 's
466ZMAGIC format, and 386BSD and BSDI's
467QMAGIC, NMAGIC, and OMAGIC
468.Xr a.out 5
469formats.
470.It Cd options COMPAT_NETBSD32
471On those architectures that support it, this enables binary
472compatibility with 32-bit applications built for the same architecture.
473This is currently limited to the amd64 and sparc64 ports, and only
474applicable for 64-bit kernels.
475.It Cd options COMPAT_SVR4_32
476On those architectures that support it, this enables binary
477compatibility with 32-bit SVR4 applications built for the same architecture.
478This is currently limited to the sparc64 port, and only applicable for
47964-bit kernels.
480.It Cd options COMPAT_AOUT_M68K
481On m68k architectures which have switched to ELF,
482this enables binary compatibility with
483.Nx Ns /m68k
484.Xr a.out 5
485executables on
486.Nx Ns /m68k
487ELF kernels.
488This handles alignment incompatibility of m68k ABI between
489a.out and ELF which causes the structure padding differences.
490Currently only some system calls which use
491.Va struct stat
492are adjusted and some binaries which use
493.Xr sysctl 3
494to retrieve network details would not work properly.
495.It Cd options EMUL_NATIVEROOT=string
496Just like emulated binaries first try looking up files in
497an emulation root (e.g.
498.Pa /emul/linux )
499before looking them up in real root, this option causes native
500binaries to first look up files in an "emulation" directory too.
501This can be useful to test an amd64 kernel on top of an i386 system
502before full migration: by unpacking the amd64 distribution in e.g.
503.Pa /emul/netbsd64
504and specifying that location as
505.Cd EMUL_NATIVEROOT ,
506native amd64 binaries can be run while the root file system remains
507populated with i386 binaries.
508Beware of
509.Pa /dev
510incompatibilities between i386 and amd64 if you do this.
511.It Cd options EXEC_ELF_NOTELESS
512Run unidentified ELF binaries as
513.Nx
514binaries.
515This might be needed for very old
516.Nx
517ELF binaries on some archs.
518These old binaries didn't contain an appropriate
519.Li .note.netbsd.ident
520section, and thus can't be identified by the kernel as
521.Nx
522binaries otherwise.
523Beware - if this option is on, the kernel would run
524.Em any
525unknown ELF binaries as if they were
526.Nx
527binaries.
528.El
529.Ss Debugging Options
530.Bl -ohang
531.It Cd options DDB
532Compiles in a kernel debugger for diagnosing kernel problems.
533See
534.Xr ddb 4
535for details.
536.Em NOTE :
537not available on all architectures.
538.It Cd options DDB_FROMCONSOLE=integer
539If set to non-zero, DDB may be entered by sending a break on a serial
540console or by a special key sequence on a graphics console.
541A value of "0" ignores console breaks or key sequences.
542If not explicitly specified, the default value is "1".
543Note that this sets the value of the
544.Em ddb.fromconsole
545.Xr sysctl 3
546variable which may be changed at run time \(em see
547.Xr sysctl 8
548for details.
549.It Cd options DDB_HISTORY_SIZE=integer
550If this is non-zero, enable history editing in the kernel debugger
551and set the size of the history to this value.
552.It Cd options DDB_ONPANIC
553The default if not specified is
554.Dq 1
555- just enter into DDB.
556If set to
557.Dq 0
558the kernel will attempt to print out a stack trace
559and reboot the system.
560If set to
561.Dq -1
562then neither a stack trace is printed or DDB entered -
563it is as if DDB were not compiled into the kernel.
564Note that this sets the value of the
565.Em ddb.onpanic
566.Xr sysctl 3
567variable which may be changed at run time \(em see
568.Xr sysctl 8
569for details.
570.It Cd options DDB_COMMANDONENTER=string
571This option specify commands which will be executed on each entry to DDB.
572This sets the default value of the
573.Em ddb.commandonenter
574.Xr sysctl 3
575variable which may be changed at run time.
576.It Cd options DDB_BREAK_CHAR=integer
577This option overrides using break to enter the kernel debugger
578on the serial console.
579The value given is the ASCII value to be used instead.
580This is currently only supported by the com driver.
581.It Cd options DDB_VERBOSE_HELP
582This option adds more verbose descriptions to the
583.Em help
584command.
585.It Cd options DDB_PANICSTACKFRAMES=integer
586Number of stack frames to display on panic.
587Useful to avoid scrolling away the interesting frames on a glass tty.
588Default value is
589.Dv 65535
590(all frames), useful value around
591.Dv 10 .
592.It Cd options KGDB
593Compiles in a remote kernel debugger stub for diagnosing kernel problems
594using the
595.Dq remote target
596feature of gdb.
597See
598.Xr gdb 1
599for details.
600.Em NOTE :
601not available on all architectures.
602.It Cd options KGDB_DEV
603Device number
604.Po
605as a
606.Dv dev_t
607.Pc
608of kgdb device.
609.It Cd options KGDB_DEVADDR
610Memory address of kgdb device.
611.It Cd options KGDB_DEVMODE
612Permissions of kgdb device.
613.It Cd options KGDB_DEVNAME
614Device name of kgdb device.
615.It Cd options KGDB_DEVRATE
616Baud rate of kgdb device.
617.It Cd makeoptions DEBUG="-g"
618The
619.Fl g
620flag causes
621.Pa netbsd.gdb
622to be built in addition to
623.Pa netbsd .
624.Pa netbsd.gdb
625is useful for debugging kernel crash dumps with gdb.
626See
627.Xr gdb 1
628for details.
629This also turns on
630.Em options DEBUG
631(which see).
632.It Cd options DEBUG
633Turns on miscellaneous kernel debugging.
634Since options are turned into preprocessor defines (see above),
635.Em options DEBUG
636is equivalent to doing a
637.Em #define DEBUG
638throughout the kernel.
639Much of the kernel has
640.Em #ifdef DEBUG
641conditionalized debugging code.
642Note that many parts of the kernel (typically device drivers) include their own
643.Em #ifdef XXX_DEBUG
644conditionals instead.
645This option also turns on certain other options,
646which may decrease system performance.
647Systems with this option are not suitable for regular use, and are
648intended only for debugging or looking for bugs.
649.It Cd options DIAGNOSTIC
650Adds code to the kernel that does internal consistency checks.
651This code will cause the kernel to panic if corruption of internal data
652structures is detected.
653Historically, the performance degradation is sufficiently small that
654it is reasonable for systems with
655.Em options DIAGNOSTIC
656to be in production use, with the real consideration not being
657performance but instead a preference for more panics versus continued
658operation with undetected problems.
659.It Cd options LOCKDEBUG
660Adds code to the kernel to detect incorrect use of locking primitives
661(mutex, rwlock).
662This code will cause the kernel to check for dead lock conditions.
663It will also check for memory being freed to not contain initialised
664lock primitives.
665Functions for use in
666.Xr ddb 4
667to check lock chains etc. are also enabled.
668These checks are very expensive and can decrease performance on
669multi-processor machines by a factor of three.
670.It Cd options KDTRACE_HOOKS
671Adds hooks for the DTrace tracing facility, which allows users to
672analyze many aspects of system and application behavior.
673See
674.Xr dtrace 1
675for details.
676.It Cd options KSTACK_CHECK_MAGIC
677Check kernel stack usage and panic if stack overflow is detected.
678This check is performance sensitive because it scans stack on each context
679switch.
680.It Cd options KTRACE
681Add hooks for the system call tracing facility, which allows users to
682watch the system call invocation behavior of processes.
683See
684.Xr ktrace 1
685for details.
686.It Cd options MSGBUFSIZE=integer
687This option sets the size of the kernel message buffer.
688This buffer holds the kernel output of
689.Fn printf
690when not (yet) read by
691.Xr syslogd 8 .
692This is particularly useful when the system has crashed and you wish to lookup
693the kernel output from just before the crash.
694Also, since the autoconfig output becomes more and more verbose,
695it sometimes happens that the message buffer overflows before
696.Xr syslogd 8
697was able to read it.
698Note that not all systems are capable of obtaining a variable sized message
699buffer.
700There are also some systems on which memory contents are not preserved
701across reboots.
702.It Cd options KERNHIST
703Enables the kernel history logs, which create in-memory traces of
704various kernel activities.
705These logs can be displayed by using
706.Cm show kernhist
707from DDB.
708See the kernel source file
709.Pa sys/kern/kern_history.c
710and the
711.Xr kernhist 9
712manual for details.
713.It Cd options KERNHIST_PRINT
714Prints the kernel history logs on the system console as entries are added.
715Note that the output is
716.Em extremely
717voluminous, so this option is really only useful for debugging
718the very earliest parts of kernel initialization.
719.It Cd options UVMHIST
720Like
721.Em KERNHIST ,
722it enables the UVM history logs.
723These logs can be displayed by using
724.Cm show kernhist
725from DDB.
726See the kernel source file
727.Pa sys/uvm/uvm_stat.c
728for details.
729.It Cd options UVMHIST_PRINT
730Like
731.Em UVMHIST ,
732it prints the UVM history logs on the system console as entries are added.
733Note that the output is
734.Em extremely
735voluminous, so this option is really only useful for debugging
736the very earliest parts of kernel initialization.
737.It Cd options UVMHIST_MAPHIST_SIZE
738Set the size of the
739.Dq maphist
740kernel history.
741The default is 100.
742This option depends upon the
743.Em UVMHIST
744option.
745.It Cd options UVMHIST_PDHIST_SIZE
746Set the size of the
747.Dq pdhist
748kernel history.
749The default is 100.
750This option depends upon the
751.Em UVMHIST
752option.
753.It Cd options BIOHIST
754Like
755.Em KERNHIST ,
756it enables the BIO history logs.
757These logs can be displayed by using
758.Cm show kernhist
759from DDB, and can help in debugging problems with Buffered I/O operations.
760See the kernel source file
761.Pa sys/kern/vfs_vio.c
762for details.
763.It Cd options BIOHIST_PRINT
764Like
765.Em BIOHIST ,
766it prints the BIO history logs on the system console as entries are added.
767Note that the output is
768.Em extremely
769voluminous, so this option is really only useful for debugging
770the very earliest parts of kernel initialization.
771.It Cd options BIOHIST_SIZE
772Set the size of the
773.Dq biohist
774kernel history.
775The default is 500.
776This option depends upon the
777.Em BIOHIST
778option.
779.El
780.Ss File Systems
781.Bl -ohang
782.It Cd file-system FFS
783Includes code implementing the Berkeley Fast File System
784.Po Em FFS Pc .
785Most machines need this if they are not running diskless.
786.It Cd file-system EXT2FS
787Includes code implementing the Second Extended File System
788.Po Em ext2 Pc ,
789revision 0 and revision 1 with the
790.Em filetype ,
791.Em sparse_super
792and
793.Em large_file
794options.
795This is the most commonly used file system on the Linux operating system,
796and is provided here for compatibility.
797Some of the specific features of
798.Em ext2
799like the "behavior on errors" are not implemented.
800See
801.Xr mount_ext2fs 8
802for details.
803.It Cd file-system LFS
804.Bq Em EXPERIMENTAL
805Include the Log-structured File System
806.Po Em LFS Pc .
807See
808.Xr mount_lfs 8
809and
810.Xr newfs_lfs 8
811for details.
812.It Cd file-system MFS
813Include the Memory File System
814.Po Em MFS Pc .
815This file system stores files in swappable memory, and produces
816notable performance improvements when it is used as the file store
817for
818.Pa /tmp
819and similar file systems.
820See
821.Xr mount_mfs 8
822for details.
823.It Cd file-system NFS
824Include the client side of the Network File System (NFS)
825remote file sharing protocol.
826Although the bulk of the code implementing NFS
827is kernel based, several user level daemons are needed for it to work.
828See
829.Xr mount_nfs 8
830for details.
831.It Cd file-system CD9660
832Includes code for the ISO 9660 + Rock Ridge file system, which is
833the standard file system on many CD-ROM discs.
834Useful primarily if you have a CD-ROM drive.
835See
836.Xr mount_cd9660 8
837for details.
838.It Cd file-system MSDOSFS
839Includes the MS-DOS FAT file system, which is reportedly still used
840by unfortunate people who have not heard about
841.Nx .
842Also implements the Windows 95 extensions to the same, which permit
843the use of longer, mixed case file names.
844See
845.Xr mount_msdos 8
846and
847.Xr fsck_msdos 8
848for details.
849.It Cd file-system NTFS
850.Bq Em EXPERIMENTAL
851Includes code for the Microsoft Windows NT file system.
852See
853.Xr mount_ntfs 8
854for details.
855.It Cd file-system FDESC
856Includes code for a file system, conventionally mounted on
857.Pa /dev/fd ,
858which permits access to the per-process file descriptor space via
859special files in the file system.
860See
861.Xr mount_fdesc 8
862for details.
863Note that this facility is redundant, and thus unneeded on most
864.Nx
865systems, since the
866.Xr fd 4
867pseudo-device driver already provides identical functionality.
868On most
869.Nx
870systems, instances of
871.Xr fd 4
872are mknoded under
873.Pa /dev/fd/
874and on
875.Pa /dev/stdin ,
876.Pa /dev/stdout ,
877and
878.Pa /dev/stderr .
879.It Cd file-system KERNFS
880Includes code which permits the mounting of a special file system
881(normally mounted on
882.Pa /kern )
883in which files representing various kernel variables and parameters
884may be found.
885See
886.Xr mount_kernfs 8
887for details.
888.It Cd file-system NULLFS
889Includes code for a loopback file system.
890This permits portions of the file hierarchy to be re-mounted in other places.
891The code really exists to provide an example of a stackable file system layer.
892See
893.Xr mount_null 8
894for details.
895.It Cd file-system OVERLAY
896Includes code for a file system filter.
897This permits the overlay file system to intercept all access to an underlying
898file system.
899This file system is intended to serve as an example of a stacking file
900system which has a need to interpose itself between an underlying file
901system and all other access.
902See
903.Xr mount_overlay 8
904for details.
905.It Cd file-system PROCFS
906Includes code for a special file system (conventionally mounted on
907.Pa /proc )
908in which the process space becomes visible in the file system.
909Among
910other things, the memory spaces of processes running on the system are
911visible as files, and signals may be sent to processes by writing to
912.Pa ctl
913files in the procfs namespace.
914See
915.Xr mount_procfs 8
916for details.
917.It Cd file-system UDF
918.Bq Em EXPERIMENTAL
919Includes code for the UDF file system commonly found on CD and DVD
920media but also on USB sticks.
921Currently supports read and write access upto UDF 2.01 and somewhat limited
922write support for UDF 2.50.
923It is marked experimental since there is no
924.Xr fsck_udf 8 .
925See
926.Xr mount_udf 8
927for details.
928.It Cd file-system UMAPFS
929Includes a loopback file system in which user and group IDs may be
930remapped \(em this can be useful when mounting alien file systems with
931different UIDs and GIDs than the local system.
932See
933.Xr mount_umap 8
934for details.
935.It Cd file-system UNION
936.Bq Em EXPERIMENTAL
937Includes code for the union file system, which permits directories to
938be mounted on top of each other in such a way that both file systems
939remain visible \(em this permits tricks like allowing writing (and the
940deleting of files) on a read-only file system like a CD-ROM by
941mounting a local writable file system on top of the read-only file
942system.
943See
944.Xr mount_union 8
945for details.
946.It Cd file-system CODA
947.Bq Em EXPERIMENTAL
948Includes code for the Coda file system.
949Coda is a distributed file system like NFS and AFS.
950It is freely available, like NFS, but it functions much like AFS in being a
951.Dq stateful
952file system.
953Both Coda and AFS cache files on your local machine to improve performance.
954Then Coda goes a step further than AFS by letting you access the cached
955files when there is no available network, viz. disconnected laptops and
956network outages.
957In Coda, both the client and server are outside the kernel which makes
958them easier to experiment with.
959Coda is available for several UNIX and non-UNIX platforms.
960See
961.Lk http://www.coda.cs.cmu.edu
962for more details.
963.Em NOTE :
964You also need to enable the pseudo-device, vcoda, for the Coda
965file system to work.
966.It Cd file-system SMBFS
967.Bq Em EXPERIMENTAL
968Includes code for the SMB/CIFS file system.
969See
970.Xr mount_smbfs 8
971for details.
972.Em NOTE :
973You also need to enable the pseudo-device, nsmb, for the SMB
974file system to work.
975.It Cd file-system PTYFS
976.Bq Em EXPERIMENTAL
977Includes code for a special file system (normally mounted on
978.Pa /dev/pts )
979in which pseudo-terminal slave devices become visible in the file system.
980See
981.Xr mount_ptyfs 8
982for details.
983.It Cd file-system TMPFS
984Includes code for the efficient memory file system, normally used over
985.Pa /tmp .
986See
987.Xr mount_tmpfs 8
988for details.
989.It Cd file-system PUFFS
990Includes kernel support for the pass-to-userspace framework file system.
991It can be used to implement file system functionality in userspace.
992See
993.Xr puffs 3
994for more details.
995This enables for example sshfs:
996.Xr mount_psshfs 8 .
997.El
998.Ss File System Options
999.Bl -ohang
1000.It Cd options DISKLABEL_EI
1001Enable
1002.Dq Endian-Independent
1003.Xr disklabel 5
1004support.
1005This allows a system to recognize a disklabel written in the other byte order.
1006For writing, when a label already exists, its byte order is preserved.
1007Otherwise, a new label is written in the native byte order.
1008To specify the byte order explicitly, the
1009.Fl F
1010option of
1011.Xr disklabel 8
1012should be used with the
1013.Fl B
1014option in order to avoid using
1015.Xr ioctl 2 ,
1016which results in the default behavior explained above.
1017At the moment this option is restricted to the following ports:
1018amd64, bebox, emips, epoc32, evbarm, i386, ibmnws, landisk, mvmeppc, prep,
1019.\" riscv,
1020rs6000, sandpoint,
1021.\" usermode,
1022xen, and zaurus;
1023also to machines of the
1024evbmips and evbppc ports that support
1025Master Boot Record (MBR).
1026.It Cd options MAGICLINKS
1027Enables the expansion of special strings
1028.Po
1029beginning with
1030.Dq @
1031.Pc
1032when traversing symbolic links.
1033See
1034.Xr symlink 7
1035for a list of supported strings.
1036Note that this option only controls the enabling of this feature
1037by the kernel at boot-up.
1038This feature can still be manipulated with the
1039.Xr sysctl 8
1040command regardless of the setting of this option.
1041.It Cd options NFSSERVER
1042Include the server side of the
1043.Em NFS
1044(Network File System) remote file sharing protocol.
1045Although the bulk of the code implementing
1046.Em NFS
1047is kernel based, several user level daemons are needed for it to
1048work.
1049See
1050.Xr mountd 8
1051and
1052.Xr nfsd 8
1053for details.
1054.It Cd options NVNODE=integer
1055This option sets the size of the cache used by the name-to-inode translation
1056routines, (a.k.a. the
1057.Fn namei
1058cache, though called by many other names in the kernel source).
1059By default, this cache has
1060.Dv ( NPROC + NTEXT + 100 )
1061entries (NPROC set as 20 + 16 * MAXUSERS and NTEXT as 80 + NPROC / 8).
1062A reasonable way to derive a value of
1063.Dv NVNODE ,
1064should you notice a large number of namei cache misses with a tool such as
1065.Xr systat 1 ,
1066is to examine your system's current computed value with
1067.Xr sysctl 8 ,
1068(which calls this parameter "kern.maxvnodes") and to increase this value
1069until either the namei cache hit rate improves or it is determined that
1070your system does not benefit substantially from an increase in the size of
1071the namei cache.
1072.It Cd options NAMECACHE_ENTER_REVERSE
1073Causes the namei cache to always enter a reverse mapping (vnode -> name)
1074as well as a normal one.
1075Normally, this is already done for directory vnodes, to speed up the getcwd
1076operation.
1077This option will cause longer hash chains in the reverse cache, and thus
1078slow down getcwd somewhat.
1079However, it does make vnode -> path translations possible in some cases.
1080For now, only useful if strict
1081.Pa /proc/#/maps
1082emulation for Linux binaries is required.
1083.El
1084.Ss Options for FFS/UFS File Systems
1085.Bl -ohang
1086.It Cd options WAPBL
1087Enable
1088.Dq Write Ahead Physical Block Logging file system journaling .
1089This provides rapid file system consistency checking after a system outage.
1090It also provides better general use performance over regular FFS.
1091See also
1092.Xr wapbl 4 .
1093.It Cd options QUOTA
1094Enables kernel support for traditional quotas in FFS.
1095Traditional quotas store the quota information in external files and
1096require
1097.Xr quotacheck 8
1098and
1099.Xr quotaon 8
1100at boot time.
1101Traditional quotas are limited to 32-bit sizes and are at this point
1102considered a legacy feature.
1103.It Cd options QUOTA2
1104Enables kernel support for in-volume quotas in FFS.
1105The quota information is file system metadata maintained by
1106.Xr fsck 8
1107and/or WAPBL journaling.
1108MFS volumes can also use
1109.Dv QUOTA2
1110quotas; see
1111.Xr mount_mfs 8
1112for more information.
1113.It Cd options FFS_EI
1114Enable
1115.Dq Endian-Independent
1116FFS support.
1117This allows a system to mount an FFS file system created for another
1118architecture, at a small performance cost for all FFS file systems.
1119See also
1120.Xr newfs 8 ,
1121.Xr fsck_ffs 8 ,
1122.Xr dumpfs 8
1123for file system byte order status and manipulation.
1124.It Cd options FFS_NO_SNAPSHOT
1125Disable support for the creation of file system internal snapshot
1126of FFS file systems.
1127Maybe useful for install media kernels, small memory systems and
1128embedded systems which don't require the snapshot support.
1129.It Cd options UFS_EXTATTR
1130Enable extended attribute support for UFS1 file systems.
1131.It Cd options UFS_DIRHASH
1132Increase lookup performance by maintaining in-core hash tables
1133for large directories.
1134.El
1135.Ss Options for the LFS File System
1136.Bl -ohang
1137.\" .It Cd options LFS_KERNEL_RFW
1138.\" There is no documentation for this. (XXX)
1139.\" .It Cd options LFS_QUOTA
1140.\" Enable traditional quota support for LFS.
1141.\" (It is not clear if this works.)
1142.\" .It Cd options LFS_QUOTA2
1143.\" Enable modernized 64-bit quota support for LFS.
1144.\" (This does not work yet.)
1145.It Cd options LFS_EI
1146Enable
1147.Dq Endian-Independent
1148LFS support.
1149This allows (at a small performance cost) mounting an LFS file system
1150created for another architecture.
1151.\" .It Cd options LFS_EXTATTR
1152.\" Enable extended attribute support for LFS.
1153.\" (It is not clear if this works.)
1154.It Cd options LFS_DIRHASH
1155Increase lookup performance by maintaining in-core hash tables
1156for large directories.
1157.El
1158.Ss Options for the ext2fs File System
1159.Bl -ohang
1160.It Cd options EXT2FS_SYSTEM_FLAGS
1161This option changes the behavior of the APPEND and IMMUTABLE flags
1162for a file on an
1163.Em ext2
1164file system.
1165Without this option, the superuser or owner of the file can
1166set and clear them.
1167With this option, only the superuser can set them, and
1168they can't be cleared if the securelevel is greater than 0.
1169See also
1170.Xr chflags 1
1171and
1172.Xr secmodel_securelevel 9 .
1173.El
1174.Ss Options for the NFS File System
1175.Bl -ohang
1176.It Cd options NFS_BOOT_BOOTP
1177Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration
1178information if NFS is used to mount the root file system.
1179See
1180.Xr diskless 8
1181for details.
1182.It Cd options NFS_BOOT_BOOTSTATIC
1183Enable use of static values defined as
1184.Dq NFS_BOOTSTATIC_MYIP ,
1185.Dq NFS_BOOTSTATIC_GWIP ,
1186.Dq NFS_BOOTSTATIC_SERVADDR ,
1187and
1188.Dq NFS_BOOTSTATIC_SERVER
1189in kernel options to get configuration information
1190if NFS is used to mount the root file system.
1191.It Cd options NFS_BOOT_DHCP
1192Same as
1193.Dq NFS_BOOT_BOOTP ,
1194but use the DHCP extensions to the
1195BOOTP protocol (RFC 1541).
1196.It Cd options NFS_BOOT_BOOTP_REQFILE
1197Specifies the string sent in the bp_file field of the BOOTP/DHCP
1198request packet.
1199.It Cd options NFS_BOOT_BOOTPARAM
1200Enable use of the BOOTPARAM protocol, consisting of RARP and
1201BOOTPARAM RPC, to get configuration information if NFS
1202is used to mount the root file system.
1203See
1204.Xr diskless 8
1205for details.
1206.It Cd options NFS_BOOT_RWSIZE=value
1207Set the initial NFS read and write sizes for diskless-boot requests.
1208The normal default is 8Kbytes.
1209This option provides a way to lower the value (e.g., to 1024 bytes)
1210as a workaround for buggy network interface cards or boot PROMs.
1211Once booted, the read and write request sizes can be increased by
1212remounting the file system.
1213See
1214.Xr mount_nfs 8
1215for details.
1216.It Cd options NFS_V2_ONLY
1217Reduce the size of the NFS client code by omitting code that's only required
1218for NFSv3 and NQNFS support, leaving only that code required to use NFSv2
1219servers.
1220.It Cd options NFS_BOOT_TCP
1221Use NFS over TCP instead of the default UDP, for mounting root.
1222.El
1223.Ss Buffer queue strategy options
1224The following options enable alternative buffer queue strategies.
1225.Bl -ohang
1226.It Cd options BUFQ_READPRIO
1227Enable alternate buffer queue strategy for disk I/O.
1228In the default strategy, outstanding disk requests are ordered by
1229sector number and sent to the disk, regardless of whether the
1230operation is a read or write; this option gives priority to issuing
1231read requests over write requests.
1232Although requests may therefore be issued out of sector-order, causing
1233more seeks and thus lower overall throughput, interactive system
1234responsiveness under heavy disk I/O load may be improved, as processes
1235blocking on disk reads are serviced sooner (file writes typically
1236don't cause applications to block).
1237The performance effect varies greatly depending on the hardware, drive
1238firmware, file system configuration, workload, and desired performance
1239trade-off.
1240Systems using drive write-cache (most modern IDE disks, by default)
1241are unlikely to benefit and may well suffer; such disks acknowledge
1242writes very quickly, and optimize them internally according to
1243physical layout.
1244Giving these disks as many requests to work with as possible (the
1245standard strategy) will typically produce the best results, especially
1246if the drive has a large cache; the drive will silently complete
1247writes from cache as it seeks for reads.
1248Disks that support a large number of concurrent tagged requests (SCSI
1249disks and many hardware RAID controllers) expose this internal
1250scheduling with tagged responses, and don't block for reads; such
1251disks may not see a noticeable difference with either strategy.
1252However, if IDE disks are run with write-cache disabled for safety,
1253writes are not acknowledged until actually completed, and only one
1254request can be outstanding; a large number of small writes in one
1255locality can keep the disk busy, starving reads elsewhere on the disk.
1256Such systems are likely to see the most benefit from this option.
1257Finally, the performance interaction of this option with ffs soft
1258dependencies can be subtle, as that mechanism can drastically alter
1259the workload for file system metadata writes.
1260.It Cd options BUFQ_PRIOCSCAN
1261Enable another buffer queue strategy for disk I/O, per-priority cyclical scan.
1262.It Cd options NEW_BUFQ_STRATEGY
1263Synonym of
1264.Em BUFQ_READPRIO .
1265.El
1266.Ss Miscellaneous Options
1267.Bl -ohang
1268.It Cd options CPU_UCODE
1269Support cpu microcode loading via
1270.Xr cpuctl 8 .
1271.It Cd options MEMORY_DISK_DYNAMIC
1272This option makes the
1273.Xr md 4
1274RAM disk size dynamically sized.
1275It is incompatible with
1276.Xr mdsetimage 8 .
1277.It Cd options MEMORY_DISK_HOOKS
1278This option allows for some machine dependent functions to be called when
1279the
1280.Xr md 4
1281RAM disk driver is configured.
1282This can result in automatically loading a RAM disk from floppy on
1283open (among other things).
1284.It Cd options MEMORY_DISK_IS_ROOT
1285Forces the
1286.Xr md 4
1287RAM disk to be the root device.
1288This can only be overridden when
1289the kernel is booted in the 'ask-for-root' mode.
1290.It Cd options MEMORY_DISK_ROOT_SIZE=integer
1291Allocates the given number of 512 byte blocks as memory for the
1292.Xr md 4
1293RAM disk, to be populated with
1294.Xr mdsetimage 8 .
1295.It Cd options MEMORY_DISK_SERVER=0
1296Do not include the interface to a userland memory disk server process.
1297Per default, this option is set to 1, including the support code.
1298Useful for install media kernels.
1299.It Cd options MEMORY_DISK_RBFLAGS=value
1300This option sets the
1301.Xr reboot 2
1302flags used when booting with a memory disk as root file system.
1303Possible values include
1304.Dv RB_AUTOBOOT
1305(boot in the usual fashion - default value), and
1306.Dv RB_SINGLE
1307(boot in single-user mode).
1308.It Cd options MODULAR
1309Enables the framework for kernel modules (see
1310.Xr module 7 ) .
1311.It Cd options MODULAR_DEFAULT_AUTOLOAD
1312Enables the autoloading of kernel modules by default.
1313This sets the default value of the
1314.Em kern.module.autoload
1315.Xr sysctl 3
1316variable which may be changed at run time.
1317.It Cd options VND_COMPRESSION
1318Enables the
1319.Xr vnd 4
1320driver to also handle compressed images.
1321See
1322.Xr vndcompress 1 ,
1323.Xr vnd 4
1324and
1325.Xr vnconfig 8
1326for more information.
1327.It Cd options SPLDEBUG
1328Help the kernel programmer find bugs related to the interrupt priority
1329level.
1330When
1331.Fn spllower
1332or
1333.Fn splraise
1334changes the current CPU's interrupt priority level to or from
1335.Dv IPL_HIGH ,
1336record a backtrace.
1337Read
1338.Xr i386/return_address 9
1339for caveats about collecting backtraces.
1340This feature is experimental, and it is only available on i386.
1341See
1342.Pa sys/kern/subr_spldebug.c .
1343.It Cd options TFTPROOT
1344Download the root memory disk through TFTP at root mount time.
1345This enables the use of a root RAM disk without requiring it to be
1346embedded in the kernel using
1347.Xr mdsetimage 8 .
1348The RAM disk name is obtained using DHCP's filename parameter.
1349This option requires
1350.Em MEMORY_DISK_HOOKS ,
1351.Em MEMORY_DISK_DYNAMIC ,
1352and
1353.Em MEMORY_DISK_IS_ROOT .
1354It is incompatible with
1355.Em MEMORY_DISK_ROOT_SIZE .
1356.It Cd options HZ=integer
1357On ports that support it, set the system clock frequency (see
1358.Xr hz 9 )
1359to the supplied value.
1360Handle with care.
1361.It Cd options NTP
1362Turns on in-kernel precision timekeeping support used by software
1363implementing
1364.Em NTP
1365(Network Time Protocol, RFC 1305).
1366The
1367.Em NTP
1368option adds an in-kernel Phase-Locked Loop (PLL) for normal
1369.Em NTP
1370operation, and a Frequency-Locked Loop (FLL) for intermittently-connected
1371operation.
1372.Xr ntpd 8
1373will employ a user-level PLL when kernel support is unavailable,
1374but the in-kernel version has lower latency and more precision, and
1375so typically keeps much better time.
1376.Pp
1377The interface to the kernel
1378.Em NTP
1379support is provided by the
1380.Xr ntp_adjtime 2
1381and
1382.Xr ntp_gettime 2
1383system calls, which are intended for use by
1384.Xr ntpd 8
1385and are enabled by the option.
1386On systems with sub-microsecond resolution timers, or where (HZ/100000)
1387is not an integer, the
1388.Em NTP
1389option also enables extended-precision arithmetic to keep track of
1390fractional clock ticks at NTP time-format precision.
1391.It Cd options PPS_SYNC
1392This option enables a kernel serial line discipline for receiving time
1393phase signals from an external reference clock such as a radio clock.
1394.Po
1395The
1396.Em NTP
1397option (which see) must be on if the
1398.Em PPS_SYNC
1399option is used
1400.Pc .
1401Some reference clocks generate a Pulse Per Second (PPS) signal in
1402phase with their time source.
1403The
1404.Em PPS
1405line discipline receives this signal on either the data leads
1406or the DCD control lead of a serial port.
1407.Pp
1408.Em NTP
1409uses the PPS signal to discipline the local clock oscillator to a high
1410degree of precision (typically less than 50 microseconds in time and
14110.1 ppm in accuracy).
1412.Em PPS
1413can also generate a serial output pulse when the system receives a PPS
1414interrupt.
1415This can be used to measure the system interrupt latency and thus calibrate
1416.Em NTP
1417to account for it.
1418Using
1419.Em PPS
1420usually requires a gadget box
1421to convert from TTL to RS-232 signal levels.
1422The gadget box and PPS are described in more detail in the HTML documentation
1423for
1424.Xr ntpd 8
1425in
1426.Pa /usr/share/doc/html/ntp .
1427.Pp
1428.Nx
1429currently supports this option in
1430.Xr com 4
1431and
1432.Xr zsc 4 .
1433.It Cd options SETUIDSCRIPTS
1434Allows scripts with the setuid bit set to execute as the effective
1435user rather than the real user, just like binary executables.
1436.Pp
1437.Em NOTE :
1438Using this option will also enable
1439.Em options FDSCRIPTS
1440.It Cd options FDSCRIPTS
1441Allows execution of scripts with the execute bit set, but not the
1442read bit, by opening the file and passing the file descriptor to
1443the shell, rather than the filename.
1444.Pp
1445.Em NOTE :
1446Execute only (non-readable) scripts will have
1447.Va argv[0]
1448set to
1449.Pa /dev/fd/* .
1450What this option allows as far as security is
1451concerned, is the ability to safely ensure that the correct script
1452is run by the interpreter, as it is passed as an already open file.
1453.It Cd options RTC_OFFSET=integer
1454The kernel (and typically the hardware battery backed-up clock on
1455those machines that have one) keeps time in
1456.Em UTC
1457(Universal Coordinated Time, once known as
1458.Em GMT ,
1459or Greenwich Mean Time)
1460and not in the time of the local time zone.
1461The
1462.Em RTC_OFFSET
1463option is used on some ports (such as the i386) to tell the kernel
1464that the hardware clock is offset from
1465.Em UTC
1466by the specified number of minutes.
1467This is typically used when a machine boots several operating
1468systems and one of them wants the hardware clock to run in the
1469local time zone and not in
1470.Em UTC ,
1471e.g.
1472.Em RTC_OFFSET=300
1473means
1474the hardware clock is set to US Eastern Time (300 minutes behind
1475.Em UTC ) ,
1476and not
1477.Em UTC .
1478(Note:
1479.Em RTC_OFFSET
1480is used to initialize a kernel variable named
1481.Va rtc_offset
1482which is the source actually used to determine the clock offset, and
1483which may be accessed via the kern.rtc_offset sysctl variable.
1484See
1485.Xr sysctl 8
1486and
1487.Xr sysctl 3
1488for details.
1489Since the kernel clock is initialized from the hardware clock very
1490early in the boot process, it is not possible to meaningfully change
1491.Va rtc_offset
1492in system initialization scripts.
1493Changing this value currently may only be done at kernel compile
1494time or by patching the kernel and rebooting).
1495.Pp
1496.Em NOTE :
1497Unfortunately, in many cases where the hardware clock
1498is kept in local time, it is adjusted for Daylight Savings
1499Time; this means that attempting to use
1500.Em RTC_OFFSET
1501to let
1502.Nx
1503coexist with such an operating system, like Windows,
1504would necessitate changing
1505.Em RTC_OFFSET
1506twice a year.
1507As such, this solution is imperfect.
1508.It Cd options MAXUPRC=integer
1509Sets the soft
1510.Dv RLIMIT_NPROC
1511resource limit, which specifies the maximum number of simultaneous
1512processes a user is permitted to run, for process 0;
1513this value is inherited by its child processes.
1514It defaults to
1515.Em CHILD_MAX ,
1516which is currently defined to be 160.
1517Setting
1518.Em MAXUPRC
1519to a value less than
1520.Em CHILD_MAX
1521is not permitted, as this would result in a violation of the semantics of
1522.St -p1003.1-90 .
1523.It Cd options NOFILE=integer
1524Sets the soft
1525.Dv RLIMIT_NOFILE
1526resource limit, which specifies the maximum number of open
1527file descriptors for each process;
1528this value is inherited by its child processes.
1529It defaults to
1530.Em OPEN_MAX ,
1531which is currently defined to be 128.
1532.It Cd options MAXFILES=integer
1533Sets the default value of the
1534.Em kern.maxfiles
1535sysctl variable, which indicates the maximum number of files that may
1536be open in the system.
1537.It Cd options DEFCORENAME=string
1538Sets the default value of the
1539.Em kern.defcorename
1540sysctl variable, otherwise it is set to
1541.Nm %n.core .
1542See
1543.Xr sysctl 8
1544and
1545.Xr sysctl 3
1546for details.
1547.It Cd options RASOPS_CLIPPING
1548Enables clipping within the
1549.Nm rasops
1550raster-console output system.
1551.Em NOTE :
1552only available on architectures that use
1553.Nm rasops
1554for console output.
1555.It Cd options RASOPS_SMALL
1556Removes optimized character writing code from the
1557.Nm rasops
1558raster-console output system.
1559.Em NOTE :
1560only available on architectures that use
1561.Nm rasops
1562for console output.
1563.It Cd options INCLUDE_CONFIG_FILE
1564Embeds the kernel config file used to define the kernel in the kernel
1565binary itself.
1566The embedded data also includes any files directly included by the config
1567file itself, e.g.
1568.Pa GENERIC.local
1569or
1570.Pa std.$MACHINE .
1571The embedded config file can be extracted from the resulting kernel with
1572.Xr config 1
1573.Fl x ,
1574or by the following command:
1575.Bd -literal -offset indent
1576strings netbsd | sed -n 's/^_CFG_//p' | unvis
1577.Ed
1578.It Cd options INCLUDE_JUST_CONFIG
1579Similar to the above option, but includes just the actual config file,
1580not any included files.
1581.It Cd options PIPE_SOCKETPAIR
1582Use slower, but smaller socketpair(2)-based pipe implementation instead
1583of default faster, but bigger one.
1584Primarily useful for installation kernels.
1585.It Cd options USERCONF
1586Compiles in the in-kernel device configuration manager.
1587See
1588.Xr userconf 4
1589for details.
1590.It Cd options PERFCTRS
1591Compiles in kernel support for CPU performance-monitoring counters.
1592See
1593.Xr pmc 1
1594for details.
1595.Em NOTE :
1596not available on all architectures.
1597.It Cd options SCDEBUG_DEFAULT
1598Used with the
1599.Cd options SYSCALL_DEBUG
1600described below to choose which types of events are displayed.
1601.Pp
1602.Bl -tag -width "SCDEBUG_KERNHIST" -compact -offset indent
1603.It Dv SCDEBUG_CALLS
1604Show system call entry points.
1605.It Dv SCDEBUG_RETURNS
1606Show system call exit points.
1607.It Dv SCDEBUG_ALL
1608Show all system call requestes, including unimplemented calls.
1609.It Dv SCDEBUG_SHOWARGS
1610Show the arguments provided.
1611.It Dv SCDEBUG_KERNHIST
1612Store a restricted form of the system call debug in a kernel history
1613instead of printing it to the console.
1614This option relies upon
1615.Cd options KERNHIST .
1616.El
1617.Pp
1618The default value is
1619.Dv (SCDEBUG_CALLS|SCDEBUG_RETURNS|SCDEBUG_SHOWARGS) .
1620.It Cd options SYSCALL_DEBUG
1621Useful for debugging system call issues, usually in early single user bringup.
1622By default, writes entries to the system console for most system call events.
1623Can be configured with the
1624.Cd options SCDEBUG_DEFAULT
1625option to to use the
1626.Cd options KERNHIST
1627facility instead.
1628.It Cd options SYSCALL_STATS
1629Count the number of times each system call number is called.
1630The values can be read through the sysctl interface and displayed using
1631.Xr systat 1 .
1632.Em NOTE :
1633not yet available on all architectures.
1634.It Cd options SYSCALL_TIMES
1635Count the time spent (using
1636.Fn cpu_counter32 )
1637in each system call.
1638.Em NOTE :
1639Using this option will also enable
1640.Cd options SYSCALL_STATS .
1641.It Cd options SYSCALL_TIMES_HASCOUNTER
1642Force use of
1643.Fn cpu_counter32
1644even if
1645.Fn cpu_hascounter
1646reports false.
1647Useful for systems where the cycle counter doesn't run at a constant rate
1648(e.g. Soekris boxes).
1649.It Cd options XSERVER_DDB
1650A supplement to XSERVER that adds support for entering
1651.Xr ddb 4
1652while in X11.
1653.It Cd options FILEASSOC
1654Support for
1655.Xr fileassoc 9 .
1656Required for
1657.Cd options PAX_SEGVGUARD
1658and
1659.Cd pseudo-device veriexec .
1660.It Cd options FILEASSOC_NHOOKS=integer
1661Number of storage slots per file for
1662.Xr fileassoc 9 .
1663Default is 4.
1664.El
1665.Ss Networking Options
1666.Bl -ohang
1667.It Cd options GATEWAY
1668Enables
1669.Em IPFORWARDING
1670(which see)
1671and (on most ports) increases the size of
1672.Em NMBCLUSTERS
1673(which see).
1674In general,
1675.Em GATEWAY
1676is used to indicate that a system should act as a router, and
1677.Em IPFORWARDING
1678is not invoked directly.
1679(Note that
1680.Em GATEWAY
1681has no impact on protocols other than IP, such as CLNP).
1682.Em GATEWAY
1683option also compiles IPv4 and IPv6 fast forwarding code into the kernel.
1684.It Cd options ICMPPRINTFS
1685The
1686.Em ICMPPRINTFS
1687option will enable debugging information to be printed about
1688the
1689.Xr icmp 4
1690protocol.
1691.It Cd options IPFORWARDING=value
1692If
1693.Em value
1694is 1 this enables IP routing behavior.
1695If
1696.Em value
1697is 0 (the default), it disables it.
1698The
1699.Em GATEWAY
1700option sets this to 1 automatically.
1701With this option enabled, the machine will forward IP datagrams destined
1702for other machines between its interfaces.
1703Note that even without this option, the kernel will
1704still forward some packets (such as source routed packets) \(em removing
1705.Em GATEWAY
1706and
1707.Em IPFORWARDING
1708is insufficient to stop all routing through a bastion host on a
1709firewall \(em source routing is controlled independently.
1710Note that IP forwarding may be turned on and off independently of the
1711setting of the
1712.Em IPFORWARDING
1713option through the use of the
1714.Em net.inet.ip.forwarding
1715sysctl variable.
1716If
1717.Em net.inet.ip.forwarding
1718is 1, IP forwarding is on.
1719See
1720.Xr sysctl 8
1721and
1722.Xr sysctl 3
1723for details.
1724.It Cd options IFA_STATS
1725Tells the kernel to maintain per-address statistics on bytes sent
1726and received over (currently) Internet and AppleTalk addresses.
1727.\"This can be a fairly expensive operation, so you probably want to
1728.\"keep this disabled.
1729The option is not recommended as it degrades system stability.
1730.It Cd options IFQ_MAXLEN=value
1731Increases the allowed size of the network interface packet queues.
1732The default queue size is 50 packets, and you do not normally need
1733to increase it.
1734.It Cd options IPSELSRC
1735Includes support for source-address selection policies.
1736See
1737.Xr in_getifa 9 .
1738.It Cd options MROUTING
1739Includes support for IP multicast routers.
1740You certainly want
1741.Em INET
1742with this.
1743Multicast routing is controlled by the
1744.Xr mrouted 8
1745daemon.
1746See also option
1747.Cd PIM .
1748.It Cd options PIM
1749Includes support for Protocol Independent Multicast (PIM) routing.
1750You need
1751.Em MROUTING
1752and
1753.Em INET
1754with this.
1755Software using this can be found e.g. in
1756.Pa pkgsrc/net/xorp .
1757.It Cd options INET
1758Includes support for the TCP/IP protocol stack.
1759You almost certainly want this.
1760See
1761.Xr inet 4
1762for details.
1763.It Cd options INET6
1764Includes support for the IPv6 protocol stack.
1765See
1766.Xr inet6 4
1767for details.
1768Unlike
1769.Em INET ,
1770.Em INET6
1771enables multicast routing code as well.
1772This option requires
1773.Em INET
1774at this moment, but it should not.
1775.It Cd options ND6_DEBUG
1776The option sets the default value of net.inet6.icmp6.nd6_debug to 1,
1777for debugging IPv6 neighbor discovery protocol handling.
1778See
1779.Xr sysctl 3
1780for details.
1781.It Cd options IPSEC
1782Includes support for the IPsec protocol, using the implementation derived from
1783.Ox ,
1784relying on
1785.Xr opencrypto 9
1786to carry out cryptographic operations.
1787See
1788.Xr fast_ipsec 4
1789for details.
1790.It Cd options IPSEC_DEBUG
1791Enables debugging code in IPsec stack.
1792See
1793.Xr ipsec 4
1794for details.
1795The
1796.Cd IPSEC
1797option includes support for IPsec Network Address Translator traversal
1798(NAT-T), as described in RFCs 3947 and 3948.
1799This feature might be patent-encumbered in some countries.
1800.It Cd options ALTQ
1801Enabled ALTQ (Alternate Queueing).
1802For simple rate-limiting, use
1803.Xr tbrconfig 8
1804to set up the interface transmission rate.
1805To use queueing disciplines, their appropriate kernel options should also
1806be defined (documented below).
1807Queueing disciplines are managed by
1808.Xr altqd 8 .
1809See
1810.Xr altq 9
1811for details.
1812.It Cd options ALTQ_HFSC
1813Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve)
1814module.
1815HFSC supports both link-sharing and guaranteed real-time services.
1816HFSC employs a service curve based QoS model, and its unique feature
1817is an ability to decouple delay and bandwidth allocation.
1818Requires
1819.Em ALTQ_RED
1820to use the RED queueing discipline on HFSC classes, or
1821.Em ALTQ_RIO
1822to use the RIO queueing discipline on HFSC classes.
1823This option assumes
1824.Em ALTQ .
1825.It Cd options ALTQ_PRIQ
1826Include support for ALTQ-implemented PRIQ (Priority Queueing).
1827PRIQ implements a simple priority-based queueing discipline.
1828A higher priority class is always served first.
1829Requires
1830.Em ALTQ_RED
1831to use the RED queueing discipline on HFSC classes, or
1832.Em ALTQ_RIO
1833to use the RIO queueing discipline on HFSC classes.
1834This option assumes
1835.Em ALTQ .
1836.It Cd options ALTQ_WFQ
1837Include support for ALTQ-implemented WFQ (Weighted Fair Queueing).
1838WFQ implements a weighted-round robin scheduler for a set of queues.
1839A weight can be assigned to each queue to give a different proportion
1840of the link capacity.
1841A hash function is used to map a flow to one of a set of queues.
1842This option assumes
1843.Em ALTQ .
1844.It Cd options ALTQ_FIFOQ
1845Include support for ALTQ-implemented FIFO queueing.
1846FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline.
1847This option assumes
1848.Em ALTQ .
1849.It Cd options ALTQ_RIO
1850Include support for ALTQ-implemented RIO (RED with In/Out).
1851The original RIO has 2 sets of RED parameters; one for in-profile
1852packets and the other for out-of-profile packets.
1853At the ingress of the network, profile meters tag packets as IN or
1854OUT based on contracted profiles for customers.
1855Inside the network, IN packets receive preferential treatment by
1856the RIO dropper.
1857ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding
1858PHB of DiffServ (RFC 2597).
1859This option assumes
1860.Em ALTQ .
1861.It Cd options ALTQ_BLUE
1862Include support for ALTQ-implemented Blue buffer management.
1863Blue is another active buffer management mechanism.
1864This option assumes
1865.Em ALTQ .
1866.It Cd options ALTQ_FLOWVALVE
1867Include support for ALTQ-implemented Flowvalve.
1868Flowvalve is a simple implementation of a RED penalty box that identifies
1869and punishes misbehaving flows.
1870This option requires
1871.Em ALTQ_RED
1872and assumes
1873.Em ALTQ .
1874.It Cd options ALTQ_CDNR
1875Include support for ALTQ-implemented CDNR (diffserv traffic conditioner)
1876packet marking/manipulation.
1877Traffic conditioners are components to meter, mark, or drop incoming
1878packets according to some rules.
1879As opposed to queueing disciplines, traffic conditioners handle incoming
1880packets at an input interface.
1881This option assumes
1882.Em ALTQ .
1883.It Cd options ALTQ_NOPCC
1884Disables use of processor cycle counter to measure time in ALTQ.
1885This option should be defined for a non-Pentium i386 CPU which does not
1886have TSC, SMP (per-CPU counters are not in sync), or power management
1887which affects processor cycle counter.
1888This option assumes
1889.Em ALTQ .
1890.It Cd options ALTQ_IPSEC
1891Include support for IPsec in IPv4 ALTQ.
1892This option assumes
1893.Em ALTQ .
1894.It Cd options ALTQ_JOBS
1895Include support for ALTQ-implemented JoBS (Joint Buffer Management
1896and Scheduling).
1897This option assumes
1898.Em ALTQ .
1899.It Cd options ALTQ_AFMAP
1900Include support for an undocumented ALTQ feature that is used to map an IP
1901flow to an ATM VC (Virtual Circuit).
1902This option assumes
1903.Em ALTQ .
1904.It Cd options ALTQ_LOCALQ
1905Include support for ALTQ-implemented local queues.
1906Its practical use is undefined.
1907Assumes
1908.Em ALTQ .
1909.It Cd options SUBNETSARELOCAL
1910Sets default value for net.inet.ip.subnetsarelocal variable, which
1911controls whether non-directly-connected subnets of connected networks
1912are considered "local" for purposes of choosing the MSS for a TCP
1913connection.
1914This is mostly present for historic reasons and completely irrelevant if
1915you enable Path MTU discovery.
1916.It Cd options HOSTZEROBROADCAST
1917Sets default value for net.inet.ip.hostzerobroadcast variable, which
1918controls whether the zeroth host address of each connected subnet is
1919also considered a broadcast address.
1920Default value is "1", for compatibility with old systems; if this is
1921set to zero on all hosts on a subnet, you should be able to fit an extra
1922host per subnet on the
1923".0" address.
1924.It Cd options MCLSHIFT=value
1925This option is the base-2 logarithm of the size of mbuf clusters.
1926The
1927.Bx
1928networking stack keeps network packets in a linked
1929list, or chain, of kernel buffer objects called mbufs.
1930The system provides larger mbuf clusters as an optimization for
1931large packets, instead of using long chains for large packets.
1932The mbuf cluster size,
1933or
1934.Em MCLBYTES ,
1935must be a power of two, and is computed as two raised to the power
1936.Em MCLSHIFT .
1937On systems with Ethernet network adapters,
1938.Em MCLSHIFT
1939is often set to 11, giving 2048-byte mbuf clusters, large enough to
1940hold a 1500-byte Ethernet frame in a single cluster.
1941Systems with network interfaces supporting larger frame sizes like
1942ATM, FDDI, or HIPPI may perform better with
1943.Em MCLSHIFT
1944set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes,
1945respectively.
1946.It Cd options NETATALK
1947Include support for the AppleTalk protocol stack.
1948The kernel provides provision for the
1949.Em Datagram Delivery Protocol
1950(DDP), providing SOCK_DGRAM support and AppleTalk routing.
1951This stack is used by the
1952.Em NETATALK
1953package, which adds support for AppleTalk server services via user
1954libraries and applications.
1955.It Cd options BLUETOOTH
1956Include support for the Bluetooth protocol stack.
1957See
1958.Xr bluetooth 4
1959for details.
1960.It Cd options IPNOPRIVPORTS
1961Normally, only root can bind a socket descriptor to a so-called
1962.Dq privileged
1963TCP port, that is, a port number in the range 0-1023.
1964This option eliminates those checks from the kernel.
1965This can be useful if there is a desire to allow daemons without
1966privileges to bind those ports, e.g., on firewalls.
1967The security tradeoffs in doing this are subtle.
1968This option should only be used by experts.
1969.It Cd options TCP_DEBUG
1970Record the last
1971.Em TCP_NDEBUG
1972TCP packets with SO_DEBUG set, and decode to the console if
1973.Em tcpconsdebug
1974is set.
1975.It Cd options TCP_NDEBUG
1976Number of packets to record for
1977.Em TCP_DEBUG .
1978Defaults to 100.
1979.It Cd options TCP_SENDSPACE=value
1980.It Cd options TCP_RECVSPACE=value
1981These options set the max TCP window size to other sizes than the default.
1982The TCP window sizes can be altered via
1983.Xr sysctl 8
1984as well.
1985.It Cd options TCP_INIT_WIN=value
1986This option sets the initial TCP window size for non-local connections,
1987which is used when the transmission starts.
1988The default size is 1, but if the machine should act more aggressively,
1989the initial size can be set to some other value.
1990The initial TCP window size can be set via
1991.Xr sysctl 8
1992as well.
1993.It Cd options TCP_SIGNATURE
1994Enable MD5 TCP signatures (RFC 2385) to protect BGP sessions.
1995.It Cd options IPFILTER_LOG
1996This option, in conjunction with
1997.Em pseudo-device ipfilter ,
1998enables logging of IP packets using IP-Filter.
1999.It Cd options IPFILTER_LOOKUP
2000This option enables the
2001IP-Filter
2002.Xr ippool 8
2003functionality to be enabled.
2004.It Cd options IPFILTER_COMPAT
2005This option enables older IP-Filter binaries to work.
2006.It Cd options IPFILTER_DEFAULT_BLOCK
2007This option sets the default policy of IP-Filter.
2008If it is set, IP-Filter will block packets by default.
2009.It Cd options BRIDGE_IPF
2010This option causes
2011.Em bridge
2012devices to use the IP and/or IPv6 filtering hooks, forming
2013a link-layer filter that uses protocol-layer rules.
2014This option assumes the presence of
2015.Em pseudo-device ipfilter .
2016.It Cd options MBUFTRACE
2017This option can help track down mbuf leaks.
2018When enabled, mbufs are tagged with the devices and protocols using them,
2019which slightly decreases network performance.
2020This additional information can be viewed with
2021.Xr netstat 1 :
2022.Dl Ic netstat Fl mssv
2023Not all devices or protocols support this option.
2024.El
2025.Ss Sysctl Related Options
2026.Bl -ohang
2027.It Cd options SYSCTL_DISALLOW_CREATE
2028Disallows the creation or deletion of nodes from the sysctl tree, as
2029well as the assigning of descriptions to nodes that lack them, by any
2030process.
2031These operations are still available to kernel sub-systems, including
2032loadable kernel modules.
2033.It Cd options SYSCTL_DISALLOW_KWRITE
2034Prevents processes from adding nodes to the sysctl tree that make
2035existing kernel memory areas writable.
2036Sections of kernel memory can still be read and new nodes that own
2037their own data may still be writable.
2038.It Cd options SYSCTL_DEBUG_SETUP
2039Causes the SYSCTL_SETUP routines to print a brief message when they
2040are invoked.
2041This is merely meant as an aid in determining the order in which
2042sections of the tree are created.
2043.It Cd options SYSCTL_DEBUG_CREATE
2044Prints a message each time
2045.Fn sysctl_create ,
2046the function that adds nodes to the tree, is called.
2047.It Cd options SYSCTL_INCLUDE_DESCR
2048Causes the kernel to include short, human readable descriptions for
2049nodes in the sysctl tree.
2050The descriptions can be retrieved programmatically (see
2051.Xr sysctl 3 ) ,
2052or by the sysctl binary itself (see
2053.Xr sysctl 8 ) .
2054The descriptions are meant to give an indication of the purpose and/or
2055effects of a given node's value, not replace the documentation for the
2056given subsystem as a whole.
2057.El
2058.Ss System V IPC Options
2059.Bl -ohang
2060.It Cd options SYSVMSG
2061Includes support for
2062.At V
2063style message queues.
2064See
2065.Xr msgctl 2 ,
2066.Xr msgget 2 ,
2067.Xr msgrcv 2 ,
2068.Xr msgsnd 2 .
2069.It Cd options SYSVSEM
2070Includes support for
2071.At V
2072style semaphores.
2073See
2074.Xr semctl 2 ,
2075.Xr semget 2 ,
2076.Xr semop 2 .
2077.It Cd options SEMMNI=value
2078Sets the number of
2079.At V
2080style semaphore identifiers.
2081The GENERIC config file for your port will have the default.
2082.It Cd options SEMMNS=value
2083Sets the number of
2084.At V
2085style semaphores in the system.
2086The GENERIC config file for your port will have the default.
2087.It Cd options SEMUME=value
2088Sets the maximum number of undo entries per process for
2089.At V
2090style semaphores.
2091The GENERIC config file for your port will have the default.
2092.It Cd options SEMMNU=value
2093Sets the number of undo structures in the system for
2094.At V
2095style semaphores.
2096The GENERIC config file for your port will have the default.
2097.It Cd options SYSVSHM
2098Includes support for
2099.At V
2100style shared memory.
2101See
2102.Xr shmat 2 ,
2103.Xr shmctl 2 ,
2104.Xr shmdt 2 ,
2105.Xr shmget 2 .
2106.It Cd options SHMMAXPGS=value
2107Sets the maximum number of
2108.At V
2109style shared memory pages that are available through the
2110.Xr shmget 2
2111system call.
2112Default value is 1024 on most ports.
2113See
2114.Pa /usr/include/machine/vmparam.h
2115for the default.
2116.El
2117.Ss VM Related Options
2118.Bl -ohang
2119.It Cd options NMBCLUSTERS=value
2120The number of mbuf clusters the kernel supports.
2121Mbuf clusters are MCLBYTES in size (usually 2k).
2122This is used to compute the size of the kernel VM map
2123.Em mb_map ,
2124which maps mbuf clusters.
2125Default on most ports is 1024 (2048 with
2126.Dq options GATEWAY
2127).
2128See
2129.Pa /usr/include/machine/param.h
2130for exact default information.
2131Increase this value if you get
2132.Dq mclpool limit reached
2133messages.
2134.It Cd options NKMEMPAGES=value
2135.It Cd options NKMEMPAGES_MIN=value
2136.It Cd options NKMEMPAGES_MAX=value
2137Size of kernel VM map
2138.Em kmem_map ,
2139in PAGE_SIZE-sized chunks (the VM page size; this value may be read
2140from the
2141.Xr sysctl 8
2142variable
2143.Em hw.pagesize
2144).
2145This VM map is used to map the kernel malloc arena.
2146The kernel attempts to auto-size this map based on the amount of
2147physical memory in the system.
2148Platform-specific code may place bounds on this computed size,
2149which may be viewed with the
2150.Xr sysctl 8
2151variable
2152.Em vm.nkmempages .
2153See
2154.Pa /usr/include/machine/param.h
2155for the default upper and lower bounds.
2156The related options
2157.Sq NKMEMPAGES_MIN
2158and
2159.Sq NKMEMPAGES_MAX
2160allow the bounds to be overridden in the kernel configuration file.
2161These options are provided in the event the computed value is
2162insufficient resulting in an
2163.Dq out of space in kmem_map
2164panic.
2165.It Cd options SB_MAX=value
2166Sets the max size in bytes that a socket buffer is allowed to occupy.
2167The default is 256k, but sometimes it needs to be increased, for example
2168when using large TCP windows.
2169This option can be changed via
2170.Xr sysctl 8
2171as well.
2172.It Cd options SOMAXKVA=value
2173Sets the maximum size of kernel virtual memory that the socket buffers
2174are allowed to use.
2175The default is 16MB, but in situations where for example large TCP
2176windows are used this value must also be increased.
2177This option can be changed via
2178.Xr sysctl 8
2179as well.
2180.It Cd options BUFCACHE=value
2181Size of the buffer cache as a percentage of total available RAM.
2182Ignored if BUFPAGES is also specified.
2183.It Cd options NBUF=value
2184Sets the number of buffer headers available, i.e., the number of
2185open files that may have a buffer cache entry.
2186Each buffer header
2187requires MAXBSIZE (machine dependent, but usually 65536) bytes.
2188The default value is machine dependent, but is usually equal to the
2189value of BUFPAGES.
2190.It Cd options BUFPAGES=value
2191These options set the number of pages available for the buffer cache.
2192Their default value is a machine dependent value, often calculated as
2193between 5% and 10% of total available RAM.
2194.It Cd options MAXTSIZ=bytes
2195Sets the maximum size limit of a process' text segment.
2196See
2197.Pa /usr/include/machine/vmparam.h
2198for the port-specific default.
2199.It Cd options DFLDSIZ=bytes
2200Sets the default size limit of a process' data segment, the value that
2201will be returned as the soft limit for
2202.Dv RLIMIT_DATA
2203(as returned by
2204.Xr getrlimit 2 ) .
2205See
2206.Pa /usr/include/machine/vmparam.h
2207for the port-specific default.
2208.It Cd options MAXDSIZ=bytes
2209Sets the maximum size limit of a process' data segment, the value that
2210will be returned as the hard limit for
2211.Dv RLIMIT_DATA
2212(as returned by
2213.Xr getrlimit 2 ) .
2214See
2215.Pa /usr/include/machine/vmparam.h
2216for the port-specific default.
2217.It Cd options DFLSSIZ=bytes
2218Sets the default size limit of a process' stack segment, the value that
2219will be returned as the soft limit for
2220.Dv RLIMIT_STACK
2221(as returned by
2222.Xr getrlimit 2 ) .
2223See
2224.Pa /usr/include/machine/vmparam.h
2225for the port-specific default.
2226.It Cd options MAXSSIZ=bytes
2227Sets the maximum size limit of a process' stack segment, the value that
2228will be returned as the hard limit for
2229.Dv RLIMIT_STACK
2230(as returned by
2231.Xr getrlimit 2 ) .
2232See
2233.Pa /usr/include/machine/vmparam.h
2234for the port-specific default.
2235.It Cd options DUMP_ON_PANIC=integer
2236Defaults to one.
2237If set to zero, the kernel will not dump to the dump device when
2238it panics, though dumps can still be forced via
2239.Xr ddb 4
2240with the
2241.Dq sync
2242command.
2243Note that this sets the value of the
2244.Em kern.dump_on_panic
2245.Xr sysctl 3
2246variable which may be changed at run time \(em see
2247.Xr sysctl 8
2248for details.
2249.It Cd options USE_TOPDOWN_VM
2250User space memory allocations (as made by
2251.Xr mmap 2 )
2252will be arranged in a
2253.Dq top down
2254fashion instead of the traditional
2255.Dq upwards from MAXDSIZ \&+ vm_daddr
2256method.
2257This includes the placement of
2258.Xr ld.so 1 .
2259Arranging memory in this manner allows either (or both of) the heap or
2260.Xr mmap 2
2261allocated space to grow larger than traditionally possible.
2262This option is not available on all ports, but is instead expected to be
2263offered on a port-by-port basis, after which some ports will commit to
2264using it by default.
2265See the files
2266.Pa /usr/include/uvm/uvm_param.h
2267for some implementation details, and
2268.Pa /usr/include/machine/vmparam.h
2269for port specific details including availability.
2270.It Cd options VMSWAP
2271Enable paging device/file support.
2272This option is on by default.
2273.It Cd options PDPOLICY_CLOCKPRO
2274Use CLOCK-Pro, an alternative page replace policy.
2275.El
2276.Ss Security Options
2277.Bl -ohang
2278.It Cd options INSECURE
2279Initializes the kernel security level with \-1 instead of 0.
2280This means that the system always starts in secure level \-1 mode, even when
2281running multiuser, unless the securelevel variable is set to value > \-1 in
2282.Pa /etc/rc.conf .
2283In this case the kernel security level will be raised to that value when the
2284.Pa /etc/rc.d/securelevel
2285script is run during system startup.
2286See the manual page for
2287.Xr init 8
2288for details on the implications of this.
2289The kernel secure level may manipulated by the superuser by altering the
2290.Em kern.securelevel
2291.Xr sysctl 3
2292variable (the secure level may only be lowered by a call from process ID 1,
2293i.e.,
2294.Xr init 8 ) .
2295See also
2296.Xr secmodel_securelevel 9 ,
2297.Xr sysctl 8
2298and
2299.Xr sysctl 3 .
2300.It Cd options VERIFIED_EXEC_FP_SHA256
2301Enables support for SHA256 hashes in Veriexec.
2302.It Cd options VERIFIED_EXEC_FP_SHA384
2303Enables support for SHA384 hashes in Veriexec.
2304.It Cd options VERIFIED_EXEC_FP_SHA512
2305Enables support for SHA512 hashes in Veriexec.
2306.It Cd options PAX_MPROTECT=value
2307Enables PaX MPROTECT,
2308.Xr mprotect 2
2309restrictions from the PaX project.
2310.Pp
2311The
2312.Ar value
2313is the default value for the
2314.Em global
2315knob, see
2316.Xr sysctl 3 .
2317If 0, PaX MPROTECT will be enabled only if explicitly set on programs
2318using
2319.Xr paxctl 8 .
2320If 1, PaX MPROTECT will be enabled for all programs.
2321Programs can be exempted using
2322.Xr paxctl 8 .
2323.Pp
2324See
2325.Xr security 7
2326for more details.
2327.It Cd options PAX_SEGVGUARD=value
2328Enables PaX Segvguard.
2329Requires
2330.Cd options FILEASSOC .
2331.Pp
2332The
2333.Ar value
2334is the default value for the
2335.Em global
2336knob, see
2337.Xr sysctl 3 .
2338If 0, PaX Segvguard will be enabled only if explicitly set on programs
2339using
2340.Xr paxctl 8 .
2341If 1, PaX Segvguard will be enabled to all programs, and exemption can
2342be done using
2343.Xr paxctl 8 .
2344.Pp
2345See
2346.Xr security 7
2347for more details.
2348.It Cd options PAX_ASLR=value
2349Enables PaX ASLR.
2350.Pp
2351The
2352.Ar value
2353is the default value for the
2354.Em global
2355knob, see
2356.Xr sysctl 3 .
2357If 0, PaX ASLR will be enabled only if explicitly set on programs
2358using
2359.Xr paxctl 8 .
2360If 1, PaX ASLR will be enabled to all programs, and exemption can
2361be done using
2362.Xr paxctl 8 .
2363.Pp
2364See
2365.Xr security 7
2366for more details.
2367.It Cd options USER_VA0_DISABLE_DEFAULT=value
2368Sets the initial value of the flag which controls whether user programs
2369can map virtual address 0.
2370The flag can be changed at runtime by
2371.Xr sysctl 3 .
2372.It Cd options KASLR
2373Enables Kernel ASLR.
2374This randomizes the location of the kernel image in memory.
2375.Em NOTE :
2376not available on all architectures.
2377.It Cd options SVS
2378Enables Separate Virtual Space.
2379On architectures that are designed to function with a shared address
2380space, this option explicitly isolates the kernel and user spaces.
2381.Em NOTE :
2382not available on all architectures.
2383.El
2384.Ss amiga-specific Options
2385.Bl -ohang
2386.It Cd options BB060STUPIDROM
2387When the bootloader (which passes AmigaOS ROM information) claims
2388we have a 68060 CPU without FPU, go look into the Processor
2389Configuration Register (PCR) to find out.
2390You need this with Amiga ROMs up to (at least) V40.xxx (OS3.1),
2391when you boot via the bootblocks and don't have a DraCo.
2392.It Cd options IOBZCLOCK=frequency
2393The IOBlix boards come with two different serial master clocks: older ones
2394use 24 MHz, newer ones use 22.1184 MHz.
2395The driver normally assumes the latter.
2396If your board uses 24 MHz, you can recompile your kernel with
2397options IOBZCLOCK=24000000
2398or patch the kernel variable iobzclock to the same value.
2399.It Cd options LIMITMEM=value
2400If there, limit the part of the first memory bank used by
2401.Nx
2402to value megabytes.
2403Default is unlimited.
2404.It Cd options P5PPC68KBOARD
2405Add special support for Phase5 mixed 68k+PPC boards.
2406Currently, this only affects rebooting from
2407.Nx
2408and is only needed on 68040+PPC, not on
240968060+PPC; without this, affected machines will hang after
2410.Nx
2411has shut
2412down and will only restart after a keyboard reset or a power cycle.
2413.El
2414.Ss atari-specific Options
2415.Bl -ohang
2416.It Cd options DISKLABEL_AHDI
2417Include support for AHDI (native Atari) disklabels.
2418.It Cd options DISKLABEL_NBDA
2419Include support for
2420.Nx Ns /atari
2421labels.
2422If you don't set this option, it will be set automatically.
2423.Nx Ns /atari
2424will not work without it.
2425.It Cd options FALCON_SCSI
2426Include support for the 5380-SCSI configuration as found on the Falcon.
2427.It Cd options RELOC_KERNEL
2428If set, the kernel will relocate itself to TT-RAM, if possible.
2429This will give you a slightly faster system.
2430.Em Beware
2431that on some TT030 systems,
2432the system will frequently dump with MMU-faults with this option enabled.
2433.It Cd options SERCONSOLE
2434Allow the modem1-port to act as the system-console.
2435A carrier should be active on modem1 during system boot to active
2436the console functionality.
2437.It Cd options TT_SCSI
2438Include support for the 5380-SCSI configuration as found on the TT030
2439and Hades.
2440.El
2441.Ss i386-specific Options
2442.Bl -ohang
2443.It Cd options CPURESET_DELAY=value
2444Specifies the time (in millisecond) to wait before doing a hardware reset
2445in the last phase of a reboot.
2446This gives the user a chance to see error messages from the shutdown
2447operations (like NFS unmounts, buffer cache flush, etc ...).
2448Setting this to 0 will disable the delay.
2449Default is 2 seconds.
2450.It Cd options USER_LDT
2451Include i386-specific system calls for modifying the local descriptor table,
2452used by Windows emulators.
2453.It Cd options PAE
2454Enable PAE (Physical Address Extension) mode.
2455PAE permits up to 36 bits physical addressing (64GB of physical
2456memory), and turns physical addresses to 64 bits entities in the
2457memory management subsystem.
2458Userland virtual address space remains at 32 bits (4GB).
2459PAE mode is required to enable the NX/XD (No-eXecute/eXecute Disable)
2460bit for pages, which allows marking certain ones as not being executable.
2461Any attempt to execute code from such a page will raise an exception.
2462.It Cd options REALBASEMEM=integer
2463Overrides the base memory size passed in from the boot block.
2464(Value given in kilobytes.)
2465Use this option only if the boot block reports the size incorrectly.
2466(Note that some BIOSes put the extended BIOS
2467data area at the top of base memory, and therefore report a smaller
2468base memory size to prevent programs overwriting it.
2469This is correct behavior, and you should not use the
2470.Em REALBASEMEM
2471option to access this memory).
2472.It Cd options SPECTRE_V2_GCC_MITIGATION=1
2473Enable GCC-specific Spectre variant 2 mitigations.
2474For 32-bit kernels this means these options:
2475.Bd -literal -offset indent
2476-mindirect-branch=thunk -mindirect-branch-register
2477.Ed
2478.Pp
2479For 64-bit kernels this means these options:
2480.Bd -literal -offset indent
2481-mindirect-branch=thunk-inline -mindirect-branch-register
2482.Ed
2483.It Cd options REALEXTMEM=integer
2484Overrides the extended memory size passed in from the boot block.
2485(Value given in kilobytes.
2486Extended memory does not include the first megabyte.)
2487Use this option only if the boot block reports the size incorrectly.
2488.It Cd options CYRIX_CACHE_WORKS
2489Relevant only to the Cyrix 486DLC CPU.
2490This option is used to turn on the cache in hold-flush mode.
2491It is not turned on by default because it is known to have problems in
2492certain motherboard implementations.
2493.It Cd options CYRIX_CACHE_REALLY_WORKS
2494Relevant only to the Cyrix 486DLC CPU.
2495This option is used to turn on the cache in write-back mode.
2496It is not turned on by default because it is known to have problems in
2497certain motherboard implementations.
2498In order for this option to take effect, option
2499.Em CYRIX_CACHE_WORKS
2500must also be specified.
2501.It Cd options PCIBIOS
2502Enable support for initializing the PCI bus using information from
2503the BIOS.
2504See
2505.Xr pcibios 4
2506for details.
2507.It Cd options MTRR
2508Include support for accessing MTRR registers from user-space.
2509See
2510.Xr i386_get_mtrr 2 .
2511.It Cd options BEEP_ONHALT
2512Make the system speaker emit several beeps when it is completely safe to
2513power down the computer after a
2514.Xr halt 8
2515command.
2516Requires
2517.Xr sysbeep 4
2518support.
2519.It Cd options BEEP_ONHALT_COUNT=times
2520Number of times to beep the speaker when
2521.Cd options BEEP_ONHALT
2522is enabled.
2523Defaults to 3.
2524.It Cd options BEEP_ONHALT_PITCH=hz
2525The tone frequency used when
2526.Cd options BEEP_ONHALT
2527option, in hertz.
2528Defaults to 1500.
2529.It Cd options BEEP_ONHALT_PERIOD=msecs
2530The duration of each beep when
2531.Cd options BEEP_ONHALT
2532is enabled, in milliseconds.
2533Defaults to 250.
2534.It Cd options MULTIBOOT
2535Makes the kernel Multiboot-compliant, allowing it to be booted through
2536a Multiboot-compliant boot manager such as GRUB.
2537See
2538.Xr multiboot 8
2539for more information.
2540.It Cd options SPLASHSCREEN
2541Display a splash screen during boot.
2542.It Cd options SPLASHSCREEN_PROGRESS
2543Display a progress bar at the splash screen during boot.
2544This option requires
2545.Em SPLASHSCREEN .
2546.El
2547.Ss isa-specific Options
2548Options specific to
2549.Xr isa 4
2550busses.
2551.Bl -ohang
2552.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size
2553Control the section of IO bus space used for PCMCIA bus space mapping.
2554Ideally the probed defaults are satisfactory, however in practice
2555that is not always the case.
2556See
2557.Xr pcmcia 4
2558for details.
2559.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask
2560Controls the allowable interrupts that may be used for PCMCIA
2561devices.
2562This mask is a logical-or of power-of-2s of allowable interrupts:
2563.Bd -literal -offset 04n
2564.Em "IRQ Val      IRQ Val      IRQ Val       IRQ Val"
2565 0  0x0001    4  0x0010    8  0x0100    12  0x1000
2566 1  0x0002    5  0x0020    9  0x0200    13  0x2000
2567 2  0x0004    6  0x0040   10  0x0400    14  0x4000
2568 3  0x0008    7  0x0080   11  0x0800    15  0x8000
2569.Ed
2570.It Cd options PCKBC_CNATTACH_SELFTEST
2571Perform a self test of the keyboard controller before attaching it as a
2572console.
2573This might be necessary on machines where we boot on cold iron, and
2574pckbc refuses to talk until we request a self test.
2575Currently only the netwinder port uses it.
2576.It Cd options PCKBD_CNATTACH_MAY_FAIL
2577If this option is set the PS/2 keyboard will not be used as the console
2578if it cannot be found during boot.
2579This allows other keyboards, like USB, to be the console keyboard.
2580.It Cd options PCKBD_LAYOUT=layout
2581Sets the default keyboard layout, see
2582.Xr pckbd 4 .
2583.El
2584.Ss m68k-specific Options
2585.Bl -ohang
2586.It Cd options FPU_EMULATE
2587Include support for MC68881/MC68882 emulator.
2588.It Cd options FPSP
2589Include support for 68040 floating point.
2590.It Cd options M68020,M68030,M68040,M68060
2591Include support for a specific CPU,
2592at least one (the one you are using) should be specified.
2593.It Cd options M060SP
2594Include software support for 68060.
2595This provides emulation of unimplemented
2596integer instructions as well as emulation of unimplemented floating point
2597instructions and data types and software support for floating point traps.
2598.El
2599.Ss powerpc-specific Options (OEA Only)
2600.Bl -ohang
2601.It Cd options PMAP_MEMLIMIT=value
2602Limit the amount of memory seen by the kernel to
2603.Ar value
2604bytes.
2605.It Cd options PTEGCOUNT=value
2606Specify the size of the page table as
2607.Ar value
2608PTE groups.
2609Normally, one PTEG is allocated per physical page frame.
2610.El
2611.Ss sparc-specific Options
2612.Bl -ohang
2613.It Cd options AUDIO_DEBUG
2614Enable simple event debugging of the logging of the
2615.Xr audio 4
2616device.
2617.It Cd options BLINK
2618Enable blinking of LED.
2619Blink rate is full cycle every N seconds for
2620N < then current load average.
2621See
2622.Xr getloadavg 3 .
2623.\" .It Cd options COLORFONT_CACHE
2624.\" What does this do?
2625.It Cd options COUNT_SW_LEFTOVERS
2626Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the
2627sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover
2628variables accessible from
2629.Xr ddb 4 .
2630See
2631.Xr sw 4 .
2632.It Cd options DEBUG_ALIGN
2633Adds debugging messages calls when user-requested alignment fault
2634handling happens.
2635.It Cd options DEBUG_EMUL
2636Adds debugging messages calls for emulated floating point and
2637alignment fixing operations.
2638.It Cd options DEBUG_SVR4
2639Prints registers messages calls for emulated SVR4 getcontext and
2640setcontext operations.
2641See
2642.Em options COMPAT_SVR4 .
2643.It Cd options EXTREME_DEBUG
2644Adds debugging functions callable from
2645.Xr ddb 4 .
2646The debug_pagetables, test_region and print_fe_map
2647functions print information about page tables for the SUN4M
2648platforms only.
2649.It Cd options EXTREME_EXTREME_DEBUG
2650Adds extra info to
2651.Em options EXTREME_DEBUG .
2652.It Cd options FPU_CONTEXT
2653Make
2654.Em options COMPAT_SVR4
2655getcontext and setcontext include floating point registers.
2656.It Cd options MAGMA_DEBUG
2657Adds debugging messages to the
2658.Xr magma 4
2659device.
2660.It Cd options RASTERCONS_FULLSCREEN
2661Use the entire screen for the console.
2662.It Cd options RASTERCONS_SMALLFONT
2663Use the Fixed font on the console, instead of the normal font.
2664.It Cd options SUN4
2665Support sun4 class machines.
2666.It Cd options SUN4C
2667Support sun4c class machines.
2668.It Cd options SUN4M
2669Support sun4m class machines.
2670.It Cd options SUN4_MMU3L
2671.\" XXX ???
2672Enable support for sun4 3-level MMU machines.
2673.It Cd options V9
2674Enable SPARC V9 assembler in
2675.Xr ddb 4 .
2676.El
2677.Ss sparc64-specific Options
2678.Bl -ohang
2679.It Cd options AUDIO_DEBUG
2680Enable simple event debugging of the logging of the
2681.Xr audio 4
2682device.
2683.It Cd options BLINK
2684Enable blinking of LED.
2685Blink rate is full cycle every N seconds for
2686N < then current load average.
2687See
2688.Xr getloadavg 3 .
2689.El
2690.Ss x68k-specific Options
2691.Bl -ohang
2692.It Cd options EXTENDED_MEMORY
2693Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board.
2694.It Cd options JUPITER
2695Include support for Jupiter-X MPU accelerator
2696.It Cd options ZSCONSOLE,ZSCN_SPEED=value
2697Use the built-in serial port as the system-console.
2698Speed is specified in bps, defaults to 9600.
2699.It Cd options ITE_KERNEL_ATTR=value
2700Set the kernel message attribute for ITE.
2701Value, an integer, is a logical or of the following values:
2702.Bl -tag -width 4n -compact -offset indent
2703.It 1
2704color inversed
2705.It 2
2706underlined
2707.It 4
2708bolded
2709.El
2710.El
2711.\" The following requests should be uncommented and used where appropriate.
2712.\" .Sh FILES
2713.\" .Sh EXAMPLES
2714.Sh SEE ALSO
2715.Xr config 1 ,
2716.Xr gcc 1 ,
2717.Xr gdb 1 ,
2718.Xr ktrace 1 ,
2719.Xr pmc 1 ,
2720.Xr quota 1 ,
2721.Xr vndcompress 1 ,
2722.Xr gettimeofday 2 ,
2723.Xr i386_get_mtrr 2 ,
2724.Xr i386_iopl 2 ,
2725.Xr msgctl 2 ,
2726.Xr msgget 2 ,
2727.Xr msgrcv 2 ,
2728.Xr msgsnd 2 ,
2729.Xr ntp_adjtime 2 ,
2730.Xr ntp_gettime 2 ,
2731.Xr reboot 2 ,
2732.Xr semctl 2 ,
2733.Xr semget 2 ,
2734.Xr semop 2 ,
2735.Xr shmat 2 ,
2736.Xr shmctl 2 ,
2737.Xr shmdt 2 ,
2738.Xr shmget 2 ,
2739.Xr sysctl 3 ,
2740.Xr apm 4 ,
2741.Xr ddb 4 ,
2742.Xr inet 4 ,
2743.Xr md 4 ,
2744.Xr pcibios 4 ,
2745.Xr pcmcia 4 ,
2746.Xr ppp 4 ,
2747.Xr userconf 4 ,
2748.Xr vnd 4 ,
2749.Xr wscons 4 ,
2750.Xr config 5 ,
2751.Xr edquota 8 ,
2752.Xr init 8 ,
2753.Xr mdsetimage 8 ,
2754.Xr mount_cd9660 8 ,
2755.Xr mount_fdesc 8 ,
2756.Xr mount_kernfs 8 ,
2757.Xr mount_lfs 8 ,
2758.Xr mount_mfs 8 ,
2759.Xr mount_msdos 8 ,
2760.Xr mount_nfs 8 ,
2761.Xr mount_ntfs 8 ,
2762.Xr mount_null 8 ,
2763.Xr mount_portal 8 ,
2764.Xr mount_procfs 8 ,
2765.Xr mount_udf 8 ,
2766.Xr mount_umap 8 ,
2767.Xr mount_union 8 ,
2768.Xr mrouted 8 ,
2769.Xr newfs_lfs 8 ,
2770.Xr ntpd 8 ,
2771.Xr quotaon 8 ,
2772.Xr rpc.rquotad 8 ,
2773.Xr sysctl 8 ,
2774.Xr in_getifa 9 ,
2775.Xr kernhist 9
2776.Sh HISTORY
2777The
2778.Nm
2779man page first appeared in
2780.Nx 1.3 .
2781