.\" $NetBSD: options.4,v 1.506.2.3 2023/05/13 11:45:54 martin Exp $ .\" .\" Copyright (c) 1996 .\" Perry E. Metzger. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgment: .\" This product includes software developed for the NetBSD Project .\" by Perry E. Metzger. .\" 4. The name of the author may not be used to endorse or promote products .\" derived from this software without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR .\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES .\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. .\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, .\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, .\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY .\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT .\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF .\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. .\" .\" .Dd August 20, 2019 .Dt OPTIONS 4 .Os .Sh NAME .Nm options .Nd Miscellaneous kernel configuration options .Sh SYNOPSIS .Cd cinclude ... .Cd config ... .Cd [no] file-system ... .Cd ident ... .Cd include ... .Cd [no] makeoptions ... .Cd maxusers ... .Cd [no] options ... .Cd [no] pseudo-device ... .Sh DESCRIPTION This manual page describes a number of miscellaneous kernel configuration options that may be specified in a kernel config file. See .Xr config 1 and .Xr config 5 for information on how to configure and build kernels. .Pp The .Ar no form removes a previously specified option. .Ss Keywords The following keywords are recognized in a kernel configuration file: .Bl -ohang .It Sy cinclude Qq Ar filename Conditionally includes another kernel configuration file whose name is .Ar filename , which may be double-quoted and may be an explicit path or relative to the kernel source directory. Failure to open the named file is ignored. .It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ Oo dumps on Ar dumpdev Oc Defines a configuration whose kernel executable is named .Ar exec_name , normally .Dq netbsd , with its root file system of type .Ar fstype on the device .Ar rootdev , and optionally specifying the location of kernel core dumps on the device .Ar dumpdev . .Ar dev or .Ar dumpdev and .Ar fstype may be specified as .Dq \&? , which is a wild card. The root .Ar fstype and .Ar dumpdev are optional and assumed to be wild carded if they are not specified. .It Ar device_instance No at Ar attachment \ Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc Define an instance of the device driver .Ar device_instance that attaches to the bus or device named .Ar attachment . An .Ar attachment may require additional information on where the device can be found, such as an address, channel, function, offset, and/or slot, referred to as .Ar locators , whose .Ar value often may be a wild card, .Dq \&? . Some device drivers have one or more .Ar flags that can be adjusted to affect the way they operate. .It Sy file-system Ar fs_name Op , Ar fs_name Op ... Include support for the file-system .Ar fs_name . .It Sy ident Qq Ar string Sets the kernel identification string to .Ar string . .It Sy include Qq Ar filename Functions the same as .Ar cinclude , except failure to open .Ar filename produces a fatal error. .It Sy makeoptions Ar name=value Defines a .Xr make 1 macro .Ar name with the value .Ar value in the kernel Makefile. .It Sy maxusers Ar integer Set the maxusers variable in the kernel. .It Sy no Ar keyword Ar name Op Ar arguments Op ... For the .Xr config 1 .Ar keywords file-system, makeoptions, options, and pseudo-device, .Ar no removes the file-system, makeoption, options, or pseudo-device, .Ar name . This is useful when a kernel configuration file includes another which has undesired options. .Pp For example, a local configuration file that wanted the kitchen sink, but not COMPAT_09 or bridging, might be: .Bd -literal -offset indent include "arch/i386/conf/GENERIC" no options COMPAT_09 no pseudo-device bridge .Ed .It Sy options Ar option_name Op , Ar option_name=value Op ... Specifies (or sets) the option, or comma-separated list of options, .Ar option_name . Some options expect to be assigned a value, which may be an integer, a double-quoted word, a bare word, or an empty string .Pq Qq . Note that those are eventually handled by the C compiler, so the rules of that language apply. .Pp .Em Note : Options that are not defined by device definition files are passed to the compile process as .Fl D flags to the C compiler. .It Sy pseudo-device Ar name Op Ar N Includes support for the pseudo-device .Ar name . Some pseudo-devices can have multiple or .Ar N instances. .El .Ss Compatibility Options Note that compatibility options for older .Nx releases includes support for newer releases as well. This means that typically only one of these is necessary, with the .Cd COMPAT_09 option enabling all .Nx compatibility. This does not include the .Cd COMPAT_43 or .Cd COMPAT_44 options. .Bl -ohang .It Cd options COMPAT_09 Enable binary compatibility with .Nx 0.9 . This enables support for 16-bit user, group, and process IDs (following revisions support 32-bit identifiers). It also allows the use of the deprecated .Xr getdomainname 3 , .Xr setdomainname 3 , and .Xr uname 3 syscalls. This option also allows using numeric file system identifiers rather than strings. Post .Nx 0.9 versions use string identifiers. .It Cd options COMPAT_10 Enable binary compatibility with .Nx 1.0 . This option allows the use of the file system name of .Dq ufs as an alias for .Dq ffs . The name .Dq ffs should be used post 1.0 in .Pa /etc/fstab and other files. It also adds old syscalls for the .At V shared memory interface. This was changed post 1.0 to work on 64-bit architectures. This option also enables .Dq sgtty compatibility, without which programs using the old interface produce an .Dq inappropriate ioctl error, and .Pa /dev/io only works when this option is set in the kernel, see .Xr io 4 on ports that support it. .It Cd options COMPAT_11 Enable binary compatibility with .Nx 1.1 . This allows binaries running on the i386 port to gain direct access to the io ports by opening .Pa /dev/io read/write. This functionality was replaced by .Xr i386_iopl 2 post 1.1. On the Atari port, the location of the disk label was moved after 1.1. When the .Em COMPAT_11 option is set, the kernel will read (pre) 1.1 style disk labels as a last resort. When a disk label is re-written, the old style label will be replaced with a post 1.1 style label. This also enables the .Em EXEC_ELF_NOTELESS option. .It Cd options COMPAT_12 Enable binary compatibility with .Nx 1.2 . This allows the use of old syscalls for .Fn reboot and .Fn swapon . The syscall numbers were changed post 1.2 to add functionality to the .Xr reboot 2 syscall, and the new .Xr swapctl 2 interface was introduced. This also enables the .Em EXEC_ELF_NOTELESS option. .It Cd options COMPAT_13 Enable binary compatibility with .Nx 1.3 . This allows the use of old syscalls for .Fn sigaltstack , and also enables the old .Xr swapctl 2 command .Dv SWAP_STATS (now called .Dv SWAP_OSTATS ) , which does not include the .Fa se_path member of .Va struct swapent . .It Cd options COMPAT_14 Enable binary compatibility with .Nx 1.4 . This allows some old .Xr ioctl 2 on .Xr wscons 4 to be performed, and allows the .Dv NFSSVC_BIOD mode of the .Xr nfssvc 2 system call to be used for compatibility with the deprecated nfsiod program. .It Cd options COMPAT_15 Enable binary compatibility with .Nx 1.5 . Since there were no API changes from .Nx 1.5 and .Nx 1.6 , this option does nothing. .It Cd options COMPAT_16 Enable binary compatibility with .Nx 1.6 . This allows the use of old signal trampoline code which has been deprecated with the addition of .Xr siginfo 2 . .It Cd options COMPAT_20 Enable binary compatibility with .Nx 2.0 . This allows the use of old syscalls for .Fn statfs , .Fn fstatfs , .Fn getfsstat and .Fn fhstatfs , which have been deprecated with the addition of the .Xr statvfs 2 , .Xr fstatvfs 2 , .Xr getvfsstat 2 and .Xr fhstatvfs 2 system calls. .It Cd options COMPAT_30 Enable binary compatibility with .Nx 3.0 . See .Xr compat_30 8 for details about the changes made after the .Nx 3.0 release. .It Cd options COMPAT_40 Enable binary compatibility with .Nx 4.0 . This allows the use of old .Xr ptrace 2 calls for the SH3 platform. It also enables the old .Xr mount 2 system call that did not include the data length parameter. The power_event_t structure's pev_switch is filled in. .It Cd options COMPAT_43 Enables compatibility with .Bx 4.3 . This adds an old syscall for .Xr lseek 2 . It also adds the ioctls for .Dv TIOCGETP and .Dv TIOCSETP . The return values for .Xr getpid 2 , .Xr getgid 2 , and .Xr getuid 2 syscalls are modified as well, to return the parent's PID and UID as well as the current process's. It also enables the deprecated .Dv NTTYDISC terminal line discipline. It also provides backwards compatibility with .Dq old SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including binary compatibility with code written before the introduction of the sa_len field in sockaddrs. It also enables support for some older pre .Bx 4.4 socket calls. .It Cd options COMPAT_50 Enable binary compatibility with .Nx 5.0 . This enables support for the old .Ft time_t and .Ft dev_t types as 32 bit, and all the associated kernel interface changes. It also enables old .Xr gpio 4 and .Xr rnd 4 interfaces. .It Cd options COMPAT_60 Enable binary compatibility with .Nx 6.0 . This provides old .Xr ccd 4 interfaces, enables support for old .Xr cpuctl 8 microcode interfaces, and support for the old .Ft ptmget structure. .It Cd options COMPAT_70 Enable binary compatibility with .Nx 7.0 . This provides support for old .Xr route 4 interfaces. .It Cd options COMPAT_BSDPTY This option is currently on by default and enables the pty multiplexer .Xr ptm 4 and .Xr ptmx 4 to find and use ptys named .Pa /dev/ptyXX (master) and .Pa /dev/ttyXX (slave). Eventually this option will become optional as ptyfs based pseudo-ttys become the default, see .Xr mount_ptyfs 8 . .It Cd options COMPAT_LINUX On those architectures that support it, this enables binary compatibility with Linux ELF and .Xr a.out 5 applications built for the same architecture. This currently includes the alpha, arm, i386, m68k, mips, powerpc and x86_64 ports. .It Cd options COMPAT_LINUX32 On those 64 bit architectures that support it, this enables binary compatibility with 32 bit Linux binaries. For now this is limited to running i386 ELF Linux binaries on amd64. .It Cd options COMPAT_SUNOS On those architectures that support it, this enables binary compatibility with SunOS 4.1 applications built for the same architecture. This currently includes the sparc, sparc64 and most or all m68k ports. Note that the sparc64 requires the .Em COMPAT_NETBSD32 option for 64-bit kernels, in addition to this option. .It Cd options COMPAT_ULTRIX On those architectures that support it, this enables binary compatibility with ULTRIX applications built for the same architecture. This currently is limited to the pmax. The functionality of this option is unknown. .It Cd options COMPAT_FREEBSD On those architectures that support it, this enables binary compatibility with .Fx applications built for the same architecture. At the moment this is limited to the i386 port. .It Cd options COMPAT_NOMID Enable compatibility with .Xr a.out 5 executables that lack a machine ID. This includes .Nx 0.8 Ns 's ZMAGIC format, and 386BSD and BSDI's QMAGIC, NMAGIC, and OMAGIC .Xr a.out 5 formats. .It Cd options COMPAT_NETBSD32 On those architectures that support it, this enables binary compatibility with 32-bit applications built for the same architecture. This is currently limited to the amd64 and sparc64 ports, and only applicable for 64-bit kernels. .It Cd options COMPAT_AOUT_M68K On m68k architectures which have switched to ELF, this enables binary compatibility with .Nx Ns /m68k .Xr a.out 5 executables on .Nx Ns /m68k ELF kernels. This handles alignment incompatibility of m68k ABI between a.out and ELF which causes the structure padding differences. Currently only some system calls which use .Va struct stat are adjusted and some binaries which use .Xr sysctl 3 to retrieve network details would not work properly. .It Cd options EMUL_NATIVEROOT=string Just like emulated binaries first try looking up files in an emulation root (e.g. .Pa /emul/linux ) before looking them up in real root, this option causes native binaries to first look up files in an "emulation" directory too. This can be useful to test an amd64 kernel on top of an i386 system before full migration: by unpacking the amd64 distribution in e.g. .Pa /emul/netbsd64 and specifying that location as .Cd EMUL_NATIVEROOT , native amd64 binaries can be run while the root file system remains populated with i386 binaries. Beware of .Pa /dev incompatibilities between i386 and amd64 if you do this. .It Cd options EXEC_ELF_NOTELESS Run unidentified ELF binaries as .Nx binaries. This might be needed for very old .Nx ELF binaries on some archs. These old binaries didn't contain an appropriate .Li .note.netbsd.ident section, and thus can't be identified by the kernel as .Nx binaries otherwise. Beware - if this option is on, the kernel would run .Em any unknown ELF binaries as if they were .Nx binaries. .El .Ss Debugging Options .Bl -ohang .It Cd options DDB Compiles in a kernel debugger for diagnosing kernel problems. See .Xr ddb 4 for details. .Em NOTE : not available on all architectures. .It Cd options DDB_FROMCONSOLE=integer If set to non-zero, DDB may be entered by sending a break on a serial console or by a special key sequence on a graphics console. A value of "0" ignores console breaks or key sequences. If not explicitly specified, the default value is "1". Note that this sets the value of the .Em ddb.fromconsole .Xr sysctl 3 variable which may be changed at run time \(em see .Xr sysctl 8 for details. .It Cd options DDB_HISTORY_SIZE=integer If this is non-zero, enable history editing in the kernel debugger and set the size of the history to this value. .It Cd options DDB_ONPANIC The default if not specified is .Dq 1 - just enter into DDB. If set to .Dq 0 the kernel will attempt to print out a stack trace and reboot the system. If set to .Dq -1 then neither a stack trace is printed or DDB entered - it is as if DDB were not compiled into the kernel. Note that this sets the value of the .Em ddb.onpanic .Xr sysctl 3 variable which may be changed at run time \(em see .Xr sysctl 8 for details. .It Cd options DDB_COMMANDONENTER=string This option specify commands which will be executed on each entry to DDB. This sets the default value of the .Em ddb.commandonenter .Xr sysctl 3 variable which may be changed at run time. .It Cd options DDB_BREAK_CHAR=integer This option overrides using break to enter the kernel debugger on the serial console. The value given is the ASCII value to be used instead. This is currently only supported by the com driver. .It Cd options DDB_VERBOSE_HELP This option adds more verbose descriptions to the .Em help command. .It Cd options DDB_PANICSTACKFRAMES=integer Number of stack frames to display on panic. Useful to avoid scrolling away the interesting frames on a glass tty. Default value is .Dv 65535 (all frames), useful value around .Dv 10 . .It Cd options KGDB Compiles in a remote kernel debugger stub for diagnosing kernel problems using the .Dq remote target feature of gdb. See .Xr gdb 1 for details. .Em NOTE : not available on all architectures. .It Cd options KGDB_DEV Device number .Po as a .Dv dev_t .Pc of kgdb device. .It Cd options KGDB_DEVADDR Memory address of kgdb device. .It Cd options KGDB_DEVMODE Permissions of kgdb device. .It Cd options KGDB_DEVNAME Device name of kgdb device. .It Cd options KGDB_DEVRATE Baud rate of kgdb device. .It Cd makeoptions DEBUG="-g" The .Fl g flag causes .Pa netbsd.gdb to be built in addition to .Pa netbsd . .Pa netbsd.gdb is useful for debugging kernel crash dumps with gdb. See .Xr gdb 1 for details. .It Cd options DEBUG Turns on miscellaneous kernel debugging. Since options are turned into preprocessor defines (see above), .Em options DEBUG is equivalent to doing a .Em #define DEBUG throughout the kernel. Much of the kernel has .Em #ifdef DEBUG conditionalized debugging code. Note that many parts of the kernel (typically device drivers) include their own .Em #ifdef XXX_DEBUG conditionals instead. This option also turns on certain other options, which may decrease system performance. Systems with this option are not suitable for regular use, and are intended only for debugging or looking for bugs. .It Cd options DIAGNOSTIC Adds code to the kernel that does internal consistency checks. This code will cause the kernel to panic if corruption of internal data structures is detected. Historically, the performance degradation is sufficiently small that it is reasonable for systems with .Em options DIAGNOSTIC to be in production use, with the real consideration not being performance but instead a preference for more panics versus continued operation with undetected problems. .It Cd options LOCKDEBUG Adds code to the kernel to detect incorrect use of locking primitives (mutex, rwlock). This code will cause the kernel to check for dead lock conditions. It will also check for memory being freed to not contain initialised lock primitives. Functions for use in .Xr ddb 4 to check lock chains etc. are also enabled. These checks are very expensive and can decrease performance on multi-processor machines by a factor of three. .It Cd options KDTRACE_HOOKS Adds hooks for the DTrace tracing facility, which allows users to analyze many aspects of system and application behavior. See .Xr dtrace 1 for details. .It Cd options KSTACK_CHECK_MAGIC Check kernel stack usage and panic if stack overflow is detected. This check is performance sensitive because it scans stack on each context switch. .It Cd options KTRACE Add hooks for the system call tracing facility, which allows users to watch the system call invocation behavior of processes. See .Xr ktrace 1 for details. .It Cd options MSGBUFSIZE=integer This option sets the size of the kernel message buffer. This buffer holds the kernel output of .Fn printf when not (yet) read by .Xr syslogd 8 . This is particularly useful when the system has crashed and you wish to lookup the kernel output from just before the crash. Also, since the autoconfig output becomes more and more verbose, it sometimes happens that the message buffer overflows before .Xr syslogd 8 was able to read it. Note that not all systems are capable of obtaining a variable sized message buffer. There are also some systems on which memory contents are not preserved across reboots. .It Cd options KERNHIST Enables the kernel history logs, which create in-memory traces of various kernel activities. These logs can be displayed by using .Cm show kernhist from DDB. See the kernel source file .Pa sys/kern/kern_history.c and the .Xr kernhist 9 manual for details. .It Cd options KERNHIST_PRINT Prints the kernel history logs on the system console as entries are added. Note that the output is .Em extremely voluminous, so this option is really only useful for debugging the very earliest parts of kernel initialization. .It Cd options UVMHIST Like .Em KERNHIST , it enables the UVM history logs. These logs can be displayed by using .Cm show kernhist from DDB. See the kernel source file .Pa sys/uvm/uvm_stat.c for details. .It Cd options UVMHIST_PRINT Like .Em UVMHIST , it prints the UVM history logs on the system console as entries are added. Note that the output is .Em extremely voluminous, so this option is really only useful for debugging the very earliest parts of kernel initialization. .It Cd options UVMHIST_MAPHIST_SIZE Set the size of the .Dq maphist kernel history. The default is 100. This option depends upon the .Em UVMHIST option. .It Cd options UVMHIST_PDHIST_SIZE Set the size of the .Dq pdhist kernel history. The default is 100. This option depends upon the .Em UVMHIST option. .It Cd options BIOHIST Like .Em KERNHIST , it enables the BIO history logs. These logs can be displayed by using .Cm show kernhist from DDB, and can help in debugging problems with Buffered I/O operations. See the kernel source file .Pa sys/kern/vfs_vio.c for details. .It Cd options BIOHIST_PRINT Like .Em BIOHIST , it prints the BIO history logs on the system console as entries are added. Note that the output is .Em extremely voluminous, so this option is really only useful for debugging the very earliest parts of kernel initialization. .It Cd options BIOHIST_SIZE Set the size of the .Dq biohist kernel history. The default is 500. This option depends upon the .Em BIOHIST option. .El .Ss File Systems .Bl -ohang .It Cd file-system FFS Includes code implementing the Berkeley Fast File System .Po Em FFS Pc . Most machines need this if they are not running diskless. .It Cd file-system EXT2FS Includes code implementing the Second Extended File System .Po Em ext2 Pc , revision 0 and revision 1 with the .Em filetype , .Em sparse_super and .Em large_file options. This is the most commonly used file system on the Linux operating system, and is provided here for compatibility. Some of the specific features of .Em ext2 like the "behavior on errors" are not implemented. See .Xr mount_ext2fs 8 for details. .It Cd file-system LFS .Bq Em EXPERIMENTAL Include the Log-structured File System .Po Em LFS Pc . See .Xr mount_lfs 8 and .Xr newfs_lfs 8 for details. .It Cd file-system MFS Include the Memory File System .Po Em MFS Pc . This file system stores files in swappable memory, and produces notable performance improvements when it is used as the file store for .Pa /tmp and similar file systems. See .Xr mount_mfs 8 for details. .It Cd file-system NFS Include the client side of the Network File System (NFS) remote file sharing protocol. Although the bulk of the code implementing NFS is kernel based, several user level daemons are needed for it to work. See .Xr mount_nfs 8 for details. .It Cd file-system CD9660 Includes code for the ISO 9660 + Rock Ridge file system, which is the standard file system on many CD-ROM discs. Useful primarily if you have a CD-ROM drive. See .Xr mount_cd9660 8 for details. .It Cd file-system MSDOSFS Includes the MS-DOS FAT file system, which is reportedly still used by unfortunate people who have not heard about .Nx . Also implements the Windows 95 extensions to the same, which permit the use of longer, mixed case file names. See .Xr mount_msdos 8 and .Xr fsck_msdos 8 for details. .It Cd file-system NTFS .Bq Em EXPERIMENTAL Includes code for the Microsoft Windows NT file system. See .Xr mount_ntfs 8 for details. .It Cd file-system FDESC Includes code for a file system, conventionally mounted on .Pa /dev/fd , which permits access to the per-process file descriptor space via special files in the file system. See .Xr mount_fdesc 8 for details. Note that this facility is redundant, and thus unneeded on most .Nx systems, since the .Xr fd 4 pseudo-device driver already provides identical functionality. On most .Nx systems, instances of .Xr fd 4 are mknoded under .Pa /dev/fd/ and on .Pa /dev/stdin , .Pa /dev/stdout , and .Pa /dev/stderr . .It Cd file-system KERNFS Includes code which permits the mounting of a special file system (normally mounted on .Pa /kern ) in which files representing various kernel variables and parameters may be found. See .Xr mount_kernfs 8 for details. .It Cd file-system NULLFS Includes code for a loopback file system. This permits portions of the file hierarchy to be re-mounted in other places. The code really exists to provide an example of a stackable file system layer. See .Xr mount_null 8 for details. .It Cd file-system OVERLAY Includes code for a file system filter. This permits the overlay file system to intercept all access to an underlying file system. This file system is intended to serve as an example of a stacking file system which has a need to interpose itself between an underlying file system and all other access. See .Xr mount_overlay 8 for details. .It Cd file-system PROCFS Includes code for a special file system (conventionally mounted on .Pa /proc ) in which the process space becomes visible in the file system. Among other things, the memory spaces of processes running on the system are visible as files, and signals may be sent to processes by writing to .Pa ctl files in the procfs namespace. See .Xr mount_procfs 8 for details. .It Cd file-system UDF .Bq Em EXPERIMENTAL Includes code for the UDF file system commonly found on CD and DVD media but also on USB sticks. Currently supports read and write access upto UDF 2.01 and somewhat limited write support for UDF 2.50. It is marked experimental since there is no .Xr fsck_udf 8 . See .Xr mount_udf 8 for details. .It Cd file-system UMAPFS Includes a loopback file system in which user and group IDs may be remapped \(em this can be useful when mounting alien file systems with different UIDs and GIDs than the local system. See .Xr mount_umap 8 for details. .It Cd file-system UNION .Bq Em EXPERIMENTAL Includes code for the union file system, which permits directories to be mounted on top of each other in such a way that both file systems remain visible \(em this permits tricks like allowing writing (and the deleting of files) on a read-only file system like a CD-ROM by mounting a local writable file system on top of the read-only file system. See .Xr mount_union 8 for details. .It Cd file-system CODA .Bq Em EXPERIMENTAL Includes code for the Coda file system. Coda is a distributed file system like NFS and AFS. It is freely available, like NFS, but it functions much like AFS in being a .Dq stateful file system. Both Coda and AFS cache files on your local machine to improve performance. Then Coda goes a step further than AFS by letting you access the cached files when there is no available network, viz. disconnected laptops and network outages. In Coda, both the client and server are outside the kernel which makes them easier to experiment with. Coda is available for several UNIX and non-UNIX platforms. See .Lk http://www.coda.cs.cmu.edu for more details. .Em NOTE : You also need to enable the pseudo-device, vcoda, for the Coda file system to work. .It Cd file-system SMBFS .Bq Em EXPERIMENTAL Includes code for the SMB/CIFS file system. See .Xr mount_smbfs 8 for details. .Em NOTE : You also need to enable the pseudo-device, nsmb, for the SMB file system to work. .It Cd file-system PTYFS Includes code for a special file system (normally mounted on .Pa /dev/pts ) in which pseudo-terminal slave devices become visible in the file system. See .Xr mount_ptyfs 8 for details. .It Cd file-system TMPFS Includes code for the efficient memory file system, normally used over .Pa /tmp . See .Xr mount_tmpfs 8 for details. .It Cd file-system PUFFS Includes kernel support for the pass-to-userspace framework file system. It can be used to implement file system functionality in userspace. See .Xr puffs 3 for more details. This enables for example sshfs: .Xr mount_psshfs 8 . .El .Ss File System Options .Bl -ohang .It Cd options DISKLABEL_EI Enable .Dq Endian-Independent .Xr disklabel 5 support. This allows a system to recognize a disklabel written in the other byte order. For writing, when a label already exists, its byte order is preserved. Otherwise, a new label is written in the native byte order. To specify the byte order explicitly, the .Fl F option of .Xr disklabel 8 should be used with the .Fl B option in order to avoid using .Xr ioctl 2 , which results in the default behavior explained above. At the moment this option is restricted to the following ports: amd64, bebox, emips, epoc32, evbarm, i386, ibmnws, landisk, mvmeppc, prep, .\" riscv, rs6000, sandpoint, .\" usermode, xen, and zaurus; also to machines of the evbmips and evbppc ports that support Master Boot Record (MBR). .It Cd options MAGICLINKS Enables the expansion of special strings .Po beginning with .Dq @ .Pc when traversing symbolic links. See .Xr symlink 7 for a list of supported strings. Note that this option only controls the enabling of this feature by the kernel at boot-up. This feature can still be manipulated with the .Xr sysctl 8 command regardless of the setting of this option. .It Cd options NFSSERVER Include the server side of the .Em NFS (Network File System) remote file sharing protocol. Although the bulk of the code implementing .Em NFS is kernel based, several user level daemons are needed for it to work. See .Xr mountd 8 and .Xr nfsd 8 for details. .It Cd options NVNODE=integer This option sets the size of the cache used by the name-to-inode translation routines, (a.k.a. the .Fn namei cache, though called by many other names in the kernel source). By default, this cache has .Dv ( NPROC + NTEXT + 100 ) entries (NPROC set as 20 + 16 * MAXUSERS and NTEXT as 80 + NPROC / 8). A reasonable way to derive a value of .Dv NVNODE , should you notice a large number of namei cache misses with a tool such as .Xr systat 1 , is to examine your system's current computed value with .Xr sysctl 8 , (which calls this parameter "kern.maxvnodes") and to increase this value until either the namei cache hit rate improves or it is determined that your system does not benefit substantially from an increase in the size of the namei cache. .It Cd options NAMECACHE_ENTER_REVERSE Causes the namei cache to always enter a reverse mapping (vnode -> name) as well as a normal one. Normally, this is already done for directory vnodes, to speed up the getcwd operation. This option will cause longer hash chains in the reverse cache, and thus slow down getcwd somewhat. However, it does make vnode -> path translations possible in some cases. For now, only useful if strict .Pa /proc/#/maps emulation for Linux binaries is required. .El .Ss Options for FFS/UFS File Systems .Bl -ohang .It Cd options APPLE_UFS Enable support for UFS file systems created on Mac OS X. .It Cd options FFS_EI Enable .Dq Endian-Independent FFS support. This allows a system to mount an FFS file system created for another architecture, at a small performance cost for all FFS file systems. See also .Xr newfs 8 , .Xr fsck_ffs 8 , .Xr dumpfs 8 for file system byte order status and manipulation. .It Cd options FFS_NO_SNAPSHOT Disable support for the creation of file system internal snapshot of FFS file systems. Maybe useful for install media kernels, small memory systems and embedded systems which don't require the snapshot support. .It Cd options QUOTA Enables kernel support for traditional quotas in FFS. Traditional quotas store the quota information in external files and require .Xr quotacheck 8 and .Xr quotaon 8 at boot time. Traditional quotas are limited to 32-bit sizes and are at this point considered a legacy feature. .It Cd options QUOTA2 Enables kernel support for in-volume quotas in FFS. The quota information is file system metadata maintained by .Xr fsck 8 and/or WAPBL journaling. MFS volumes can also use .Dv QUOTA2 quotas; see .Xr mount_mfs 8 for more information. .It Cd options UFS_DIRHASH Increase lookup performance by maintaining in-core hash tables for large directories. .It Cd options UFS_EXTATTR Enable extended attribute support for UFS1 file systems. .It Cd options WAPBL Enable .Dq Write Ahead Physical Block Logging file system journaling . This provides rapid file system consistency checking after a system outage. It also provides better general use performance over regular FFS. See also .Xr wapbl 4 . .El .Ss Options for the LFS File System .Bl -ohang .\" .It Cd options LFS_KERNEL_RFW .\" There is no documentation for this. (XXX) .\" .It Cd options LFS_QUOTA .\" Enable traditional quota support for LFS. .\" (It is not clear if this works.) .\" .It Cd options LFS_QUOTA2 .\" Enable modernized 64-bit quota support for LFS. .\" (This does not work yet.) .It Cd options LFS_EI Enable .Dq Endian-Independent LFS support. This allows (at a small performance cost) mounting an LFS file system created for another architecture. .\" .It Cd options LFS_EXTATTR .\" Enable extended attribute support for LFS. .\" (It is not clear if this works.) .It Cd options LFS_DIRHASH Increase lookup performance by maintaining in-core hash tables for large directories. .El .Ss Options for the ext2fs File System .Bl -ohang .It Cd options EXT2FS_SYSTEM_FLAGS This option changes the behavior of the APPEND and IMMUTABLE flags for a file on an .Em ext2 file system. Without this option, the superuser or owner of the file can set and clear them. With this option, only the superuser can set them, and they can't be cleared if the securelevel is greater than 0. See also .Xr chflags 1 and .Xr secmodel_securelevel 9 . .El .Ss Options for the NFS File System .Bl -ohang .It Cd options NFS_BOOT_BOOTP Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration information if NFS is used to mount the root file system. See .Xr diskless 8 for details. .It Cd options NFS_BOOT_BOOTSTATIC Enable use of static values defined as .Dq NFS_BOOTSTATIC_MYIP , .Dq NFS_BOOTSTATIC_GWIP , .Dq NFS_BOOTSTATIC_SERVADDR , and .Dq NFS_BOOTSTATIC_SERVER in kernel options to get configuration information if NFS is used to mount the root file system. .It Cd options NFS_BOOT_DHCP Same as .Dq NFS_BOOT_BOOTP , but use the DHCP extensions to the BOOTP protocol (RFC 1541). .It Cd options NFS_BOOT_BOOTP_REQFILE Specifies the string sent in the bp_file field of the BOOTP/DHCP request packet. .It Cd options NFS_BOOT_BOOTPARAM Enable use of the BOOTPARAM protocol, consisting of RARP and BOOTPARAM RPC, to get configuration information if NFS is used to mount the root file system. See .Xr diskless 8 for details. .It Cd options NFS_BOOT_RWSIZE=value Set the initial NFS read and write sizes for diskless-boot requests. The normal default is 8Kbytes. This option provides a way to lower the value (e.g., to 1024 bytes) as a workaround for buggy network interface cards or boot PROMs. Once booted, the read and write request sizes can be increased by remounting the file system. See .Xr mount_nfs 8 for details. .It Cd options NFS_V2_ONLY Reduce the size of the NFS client code by omitting code that's only required for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 servers. .It Cd options NFS_BOOT_TCP Use NFS over TCP instead of the default UDP, for mounting root. .El .Ss Buffer queue strategy options The following options enable alternative buffer queue strategies. .Bl -ohang .It Cd options BUFQ_READPRIO Enable alternate buffer queue strategy for disk I/O. In the default strategy, outstanding disk requests are ordered by sector number and sent to the disk, regardless of whether the operation is a read or write; this option gives priority to issuing read requests over write requests. Although requests may therefore be issued out of sector-order, causing more seeks and thus lower overall throughput, interactive system responsiveness under heavy disk I/O load may be improved, as processes blocking on disk reads are serviced sooner (file writes typically don't cause applications to block). The performance effect varies greatly depending on the hardware, drive firmware, file system configuration, workload, and desired performance trade-off. Systems using drive write-cache (most modern IDE disks, by default) are unlikely to benefit and may well suffer; such disks acknowledge writes very quickly, and optimize them internally according to physical layout. Giving these disks as many requests to work with as possible (the standard strategy) will typically produce the best results, especially if the drive has a large cache; the drive will silently complete writes from cache as it seeks for reads. Disks that support a large number of concurrent tagged requests (SCSI disks and many hardware RAID controllers) expose this internal scheduling with tagged responses, and don't block for reads; such disks may not see a noticeable difference with either strategy. However, if IDE disks are run with write-cache disabled for safety, writes are not acknowledged until actually completed, and only one request can be outstanding; a large number of small writes in one locality can keep the disk busy, starving reads elsewhere on the disk. Such systems are likely to see the most benefit from this option. Finally, the performance interaction of this option with ffs soft dependencies can be subtle, as that mechanism can drastically alter the workload for file system metadata writes. .It Cd options BUFQ_PRIOCSCAN Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. .It Cd options NEW_BUFQ_STRATEGY Synonym of .Em BUFQ_READPRIO . .El .Ss Miscellaneous Options .Bl -ohang .It Cd options CPU_UCODE Support cpu microcode loading via .Xr cpuctl 8 . .It Cd options MEMORY_DISK_DYNAMIC This option makes the .Xr md 4 RAM disk size dynamically sized. It is incompatible with .Xr mdsetimage 8 . .It Cd options MEMORY_DISK_HOOKS This option allows for some machine dependent functions to be called when the .Xr md 4 RAM disk driver is configured. This can result in automatically loading a RAM disk from floppy on open (among other things). .It Cd options MEMORY_DISK_IS_ROOT Forces the .Xr md 4 RAM disk to be the root device. This can only be overridden when the kernel is booted in the 'ask-for-root' mode. .It Cd options MEMORY_DISK_ROOT_SIZE=integer Allocates the given number of 512 byte blocks as memory for the .Xr md 4 RAM disk, to be populated with .Xr mdsetimage 8 . .It Cd options MEMORY_DISK_SERVER=0 Do not include the interface to a userland memory disk server process. Per default, this option is set to 1, including the support code. Useful for install media kernels. .It Cd options MEMORY_DISK_RBFLAGS=value This option sets the .Xr reboot 2 flags used when booting with a memory disk as root file system. Possible values include .Dv RB_AUTOBOOT (boot in the usual fashion - default value), and .Dv RB_SINGLE (boot in single-user mode). .It Cd options MODULAR Enables the framework for kernel modules (see .Xr module 7 ) . .It Cd options MODULAR_DEFAULT_AUTOLOAD Enables the autoloading of kernel modules by default. This sets the default value of the .Em kern.module.autoload .Xr sysctl 3 variable which may be changed at run time. .It Cd options VND_COMPRESSION Enables the .Xr vnd 4 driver to also handle compressed images. See .Xr vndcompress 1 , .Xr vnd 4 and .Xr vnconfig 8 for more information. .It Cd options SELFRELOC Make the kernel able to self relocate at bootstrap, so that it can run whatever its load address is. This is intented to be used withe the .Ic reloc boostrap command documented in .Xr x86/boot 8 , to workaround UEFI bugs, and is only available on amd64. .It Cd options SPLDEBUG Help the kernel programmer find bugs related to the interrupt priority level. When .Fn spllower or .Fn splraise changes the current CPU's interrupt priority level to or from .Dv IPL_HIGH , record a backtrace. Read .Xr i386/return_address 9 for caveats about collecting backtraces. This feature is experimental, and it is only available on i386. See .Pa sys/kern/subr_spldebug.c . .It Cd options TFTPROOT Download the root memory disk through TFTP at root mount time. This enables the use of a root RAM disk without requiring it to be embedded in the kernel using .Xr mdsetimage 8 . The RAM disk name is obtained using DHCP's filename parameter. This option requires .Em MEMORY_DISK_HOOKS , .Em MEMORY_DISK_DYNAMIC , and .Em MEMORY_DISK_IS_ROOT . It is incompatible with .Em MEMORY_DISK_ROOT_SIZE . .It Cd options HZ=integer On ports that support it, set the system clock frequency (see .Xr hz 9 ) to the supplied value. Handle with care. .It Cd options NTP Turns on in-kernel precision timekeeping support used by software implementing .Em NTP (Network Time Protocol, RFC 1305). The .Em NTP option adds an in-kernel Phase-Locked Loop (PLL) for normal .Em NTP operation, and a Frequency-Locked Loop (FLL) for intermittently-connected operation. .Xr ntpd 8 will employ a user-level PLL when kernel support is unavailable, but the in-kernel version has lower latency and more precision, and so typically keeps much better time. .Pp The interface to the kernel .Em NTP support is provided by the .Xr ntp_adjtime 2 and .Xr ntp_gettime 2 system calls, which are intended for use by .Xr ntpd 8 and are enabled by the option. On systems with sub-microsecond resolution timers, or where (HZ/100000) is not an integer, the .Em NTP option also enables extended-precision arithmetic to keep track of fractional clock ticks at NTP time-format precision. .It Cd options PPS_SYNC This option enables a kernel serial line discipline for receiving time phase signals from an external reference clock such as a radio clock. .Po The .Em NTP option (which see) must be on if the .Em PPS_SYNC option is used .Pc . Some reference clocks generate a Pulse Per Second (PPS) signal in phase with their time source. The .Em PPS line discipline receives this signal on either the data leads or the DCD control lead of a serial port. .Pp .Em NTP uses the PPS signal to discipline the local clock oscillator to a high degree of precision (typically less than 50 microseconds in time and 0.1 ppm in accuracy). .Em PPS can also generate a serial output pulse when the system receives a PPS interrupt. This can be used to measure the system interrupt latency and thus calibrate .Em NTP to account for it. Using .Em PPS usually requires a gadget box to convert from TTL to RS-232 signal levels. The gadget box and PPS are described in more detail in the HTML documentation for .Xr ntpd 8 in .Pa /usr/share/doc/html/ntp . .Pp .Nx currently supports this option in .Xr com 4 and .Xr zsc 4 . .It Cd options SETUIDSCRIPTS Allows scripts with the setuid bit set to execute as the effective user rather than the real user, just like binary executables. .Pp .Em NOTE : Using this option will also enable .Em options FDSCRIPTS .It Cd options FDSCRIPTS Allows execution of scripts with the execute bit set, but not the read bit, by opening the file and passing the file descriptor to the shell, rather than the filename. .Pp .Em NOTE : Execute only (non-readable) scripts will have .Va argv[0] set to .Pa /dev/fd/* . What this option allows as far as security is concerned, is the ability to safely ensure that the correct script is run by the interpreter, as it is passed as an already open file. .It Cd options RTC_OFFSET=integer The kernel (and typically the hardware battery backed-up clock on those machines that have one) keeps time in .Em UTC (Universal Coordinated Time, once known as .Em GMT , or Greenwich Mean Time) and not in the time of the local time zone. The .Em RTC_OFFSET option is used on some ports (such as the i386) to tell the kernel that the hardware clock is offset from .Em UTC by the specified number of minutes. This is typically used when a machine boots several operating systems and one of them wants the hardware clock to run in the local time zone and not in .Em UTC , e.g. .Em RTC_OFFSET=300 means the hardware clock is set to US Eastern Time (300 minutes behind .Em UTC ) , and not .Em UTC . (Note: .Em RTC_OFFSET is used to initialize a kernel variable named .Va rtc_offset which is the source actually used to determine the clock offset, and which may be accessed via the kern.rtc_offset sysctl variable. See .Xr sysctl 8 and .Xr sysctl 3 for details. Since the kernel clock is initialized from the hardware clock very early in the boot process, it is not possible to meaningfully change .Va rtc_offset in system initialization scripts. Changing this value currently may only be done at kernel compile time or by patching the kernel and rebooting). .Pp .Em NOTE : Unfortunately, in many cases where the hardware clock is kept in local time, it is adjusted for Daylight Savings Time; this means that attempting to use .Em RTC_OFFSET to let .Nx coexist with such an operating system, like Windows, would necessitate changing .Em RTC_OFFSET twice a year. As such, this solution is imperfect. .It Cd options MAXUPRC=integer Sets the soft .Dv RLIMIT_NPROC resource limit, which specifies the maximum number of simultaneous processes a user is permitted to run, for process 0; this value is inherited by its child processes. It defaults to .Em CHILD_MAX , which is currently defined to be 160. Setting .Em MAXUPRC to a value less than .Em CHILD_MAX is not permitted, as this would result in a violation of the semantics of .St -p1003.1-90 . .It Cd options NOFILE=integer Sets the soft .Dv RLIMIT_NOFILE resource limit, which specifies the maximum number of open file descriptors for each process; this value is inherited by its child processes. It defaults to .Em OPEN_MAX , which is currently defined to be 128. .It Cd options MAXFILES=integer Sets the default value of the .Em kern.maxfiles sysctl variable, which indicates the maximum number of files that may be open in the system. .It Cd options DEFCORENAME=string Sets the default value of the .Em kern.defcorename sysctl variable, otherwise it is set to .Nm %n.core . See .Xr sysctl 8 and .Xr sysctl 3 for details. .It Cd options RASOPS_CLIPPING Enables clipping within the .Nm rasops raster-console output system. .Em NOTE : only available on architectures that use .Nm rasops for console output. .It Cd options RASOPS_SMALL Removes optimized character writing code from the .Nm rasops raster-console output system. .Em NOTE : only available on architectures that use .Nm rasops for console output. .It Cd options INCLUDE_CONFIG_FILE Embeds the kernel config file used to define the kernel in the kernel binary itself. The embedded data also includes any files directly included by the config file itself, e.g. .Pa GENERIC.local or .Pa std.$MACHINE . The embedded config file can be extracted from the resulting kernel with .Xr config 1 .Fl x , or by the following command: .Bd -literal -offset indent strings netbsd | sed -n 's/^_CFG_//p' | unvis .Ed .It Cd options INCLUDE_JUST_CONFIG Similar to the above option, but includes just the actual config file, not any included files. .It Cd options PIPE_SOCKETPAIR Use slower, but smaller socketpair(2)-based pipe implementation instead of default faster, but bigger one. Primarily useful for installation kernels. .It Cd options USERCONF Compiles in the in-kernel device configuration manager. See .Xr userconf 4 for details. .It Cd options SCDEBUG_DEFAULT Used with the .Cd options SYSCALL_DEBUG described below to choose which types of events are displayed. .Pp .Bl -tag -width "SCDEBUG_KERNHIST" -compact -offset indent .It Dv SCDEBUG_CALLS Show system call entry points. .It Dv SCDEBUG_RETURNS Show system call exit points. .It Dv SCDEBUG_ALL Show all system call requestes, including unimplemented calls. .It Dv SCDEBUG_SHOWARGS Show the arguments provided. .It Dv SCDEBUG_KERNHIST Store a restricted form of the system call debug in a kernel history instead of printing it to the console. This option relies upon .Cd options KERNHIST . .El .Pp The default value is .Dv (SCDEBUG_CALLS|SCDEBUG_RETURNS|SCDEBUG_SHOWARGS) . .It Cd options SYSCALL_DEBUG Useful for debugging system call issues, usually in early single user bringup. By default, writes entries to the system console for most system call events. Can be configured with the .Cd options SCDEBUG_DEFAULT option to to use the .Cd options KERNHIST facility instead. .It Cd options SYSCALL_STATS Count the number of times each system call number is called. The values can be read through the sysctl interface and displayed using .Xr systat 1 . .Em NOTE : not yet available on all architectures. .It Cd options SYSCALL_TIMES Count the time spent (using .Fn cpu_counter32 ) in each system call. .Em NOTE : Using this option will also enable .Cd options SYSCALL_STATS . .It Cd options SYSCALL_TIMES_HASCOUNTER Force use of .Fn cpu_counter32 even if .Fn cpu_hascounter reports false. Useful for systems where the cycle counter doesn't run at a constant rate (e.g. Soekris boxes). .It Cd options XSERVER_DDB A supplement to XSERVER that adds support for entering .Xr ddb 4 while in X11. .It Cd options FILEASSOC Support for .Xr fileassoc 9 . Required for .Cd options PAX_SEGVGUARD and .Cd pseudo-device veriexec . .It Cd options FILEASSOC_NHOOKS=integer Number of storage slots per file for .Xr fileassoc 9 . Default is 4. .El .Ss Networking Options .Bl -ohang .It Cd options GATEWAY Enables .Em IPFORWARDING and (on most ports) increases the size of .Em NMBCLUSTERS . In general, .Em GATEWAY is used to indicate that a system should act as a router, and .Em IPFORWARDING is not invoked directly. (Note that .Em GATEWAY has no impact on protocols other than IP). .Em GATEWAY option also compiles IPv4 and IPv6 fast forwarding code into the kernel. .It Cd options IPFORWARDING=value If .Em value is 1 this enables IP routing behavior. If .Em value is 0 (the default), it disables it. The .Em GATEWAY option sets this to 1 automatically. With this option enabled, the machine will forward IP datagrams destined for other machines between its interfaces. Note that even without this option, the kernel will still forward some packets (such as source routed packets) \(em removing .Em GATEWAY and .Em IPFORWARDING is insufficient to stop all routing through a bastion host on a firewall \(em source routing is controlled independently. Note that IP forwarding may be turned on and off independently of the setting of the .Em IPFORWARDING option through the use of the .Em net.inet.ip.forwarding sysctl variable. If .Em net.inet.ip.forwarding is 1, IP forwarding is on. See .Xr sysctl 8 and .Xr sysctl 3 for details. .It Cd options IFA_STATS Tells the kernel to maintain per-address statistics on bytes sent and received over (currently) Internet and AppleTalk addresses. .\"This can be a fairly expensive operation, so you probably want to .\"keep this disabled. The option is not recommended as it degrades system stability. .It Cd options IFQ_MAXLEN=value Increases the allowed size of the network interface packet queues. The default queue size is 50 packets, and you do not normally need to increase it. .It Cd options IPSELSRC Includes support for source-address selection policies. See .Xr in_getifa 9 . .It Cd options MROUTING Includes support for IP multicast routers. You certainly want .Em INET with this. Multicast routing is controlled by the .Xr mrouted 8 daemon. See also option .Cd PIM . .It Cd options PIM Includes support for Protocol Independent Multicast (PIM) routing. You need .Em MROUTING and .Em INET with this. Software using this can be found e.g. in .Pa pkgsrc/net/xorp . .It Cd options INET Includes support for the TCP/IP protocol stack. You almost certainly want this. See .Xr inet 4 for details. .It Cd options INET6 Includes support for the IPv6 protocol stack. See .Xr inet6 4 for details. Unlike .Em INET , .Em INET6 enables multicast routing code as well. This option requires .Em INET at this moment, but it should not. .It Cd options ND6_DEBUG The option sets the default value of net.inet6.icmp6.nd6_debug to 1, for debugging IPv6 neighbor discovery protocol handling. See .Xr sysctl 3 for details. .It Cd options IPSEC Includes support for the IPsec protocol, using the implementation derived from .Ox , relying on .Xr opencrypto 9 to carry out cryptographic operations. See .Xr ipsec 4 for details. .It Cd options IPSEC_DEBUG Enables debugging code in IPsec stack. See .Xr ipsec 4 for details. The .Cd IPSEC option includes support for IPsec Network Address Translator traversal (NAT-T), as described in RFCs 3947 and 3948. This feature might be patent-encumbered in some countries. .It Cd options ALTQ Enabled ALTQ (Alternate Queueing). For simple rate-limiting, use .Xr tbrconfig 8 to set up the interface transmission rate. To use queueing disciplines, their appropriate kernel options should also be defined (documented below). Queueing disciplines are managed by .Xr altqd 8 . See .Xr altq 9 for details. .It Cd options ALTQ_HFSC Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) module. HFSC supports both link-sharing and guaranteed real-time services. HFSC employs a service curve based QoS model, and its unique feature is an ability to decouple delay and bandwidth allocation. Requires .Em ALTQ_RED to use the RED queueing discipline on HFSC classes, or .Em ALTQ_RIO to use the RIO queueing discipline on HFSC classes. This option assumes .Em ALTQ . .It Cd options ALTQ_PRIQ Include support for ALTQ-implemented PRIQ (Priority Queueing). PRIQ implements a simple priority-based queueing discipline. A higher priority class is always served first. Requires .Em ALTQ_RED to use the RED queueing discipline on HFSC classes, or .Em ALTQ_RIO to use the RIO queueing discipline on HFSC classes. This option assumes .Em ALTQ . .It Cd options ALTQ_WFQ Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). WFQ implements a weighted-round robin scheduler for a set of queues. A weight can be assigned to each queue to give a different proportion of the link capacity. A hash function is used to map a flow to one of a set of queues. This option assumes .Em ALTQ . .It Cd options ALTQ_FIFOQ Include support for ALTQ-implemented FIFO queueing. FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. This option assumes .Em ALTQ . .It Cd options ALTQ_RIO Include support for ALTQ-implemented RIO (RED with In/Out). The original RIO has 2 sets of RED parameters; one for in-profile packets and the other for out-of-profile packets. At the ingress of the network, profile meters tag packets as IN or OUT based on contracted profiles for customers. Inside the network, IN packets receive preferential treatment by the RIO dropper. ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding PHB of DiffServ (RFC 2597). This option assumes .Em ALTQ . .It Cd options ALTQ_BLUE Include support for ALTQ-implemented Blue buffer management. Blue is another active buffer management mechanism. This option assumes .Em ALTQ . .It Cd options ALTQ_FLOWVALVE Include support for ALTQ-implemented Flowvalve. Flowvalve is a simple implementation of a RED penalty box that identifies and punishes misbehaving flows. This option requires .Em ALTQ_RED and assumes .Em ALTQ . .It Cd options ALTQ_CDNR Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) packet marking/manipulation. Traffic conditioners are components to meter, mark, or drop incoming packets according to some rules. As opposed to queueing disciplines, traffic conditioners handle incoming packets at an input interface. This option assumes .Em ALTQ . .It Cd options ALTQ_NOPCC Disables use of processor cycle counter to measure time in ALTQ. This option should be defined for a non-Pentium i386 CPU which does not have TSC, SMP (per-CPU counters are not in sync), or power management which affects processor cycle counter. This option assumes .Em ALTQ . .It Cd options ALTQ_IPSEC Include support for IPsec in IPv4 ALTQ. This option assumes .Em ALTQ . .It Cd options ALTQ_JOBS Include support for ALTQ-implemented JoBS (Joint Buffer Management and Scheduling). This option assumes .Em ALTQ . .It Cd options ALTQ_AFMAP Include support for an undocumented ALTQ feature that is used to map an IP flow to an ATM VC (Virtual Circuit). This option assumes .Em ALTQ . .It Cd options ALTQ_LOCALQ Include support for ALTQ-implemented local queues. Its practical use is undefined. Assumes .Em ALTQ . .It Cd options SUBNETSARELOCAL Sets default value for net.inet.ip.subnetsarelocal variable, which controls whether non-directly-connected subnets of connected networks are considered "local" for purposes of choosing the MSS for a TCP connection. This is mostly present for historic reasons and completely irrelevant if you enable Path MTU discovery. .It Cd options HOSTZEROBROADCAST Sets default value for net.inet.ip.hostzerobroadcast variable, which controls whether the zeroth host address of each connected subnet is also considered a broadcast address. Default value is "1", for compatibility with old systems; if this is set to zero on all hosts on a subnet, you should be able to fit an extra host per subnet on the ".0" address. .It Cd options MCLSHIFT=value This option is the base-2 logarithm of the size of mbuf clusters. The .Bx networking stack keeps network packets in a linked list, or chain, of kernel buffer objects called mbufs. The system provides larger mbuf clusters as an optimization for large packets, instead of using long chains for large packets. The mbuf cluster size, or .Em MCLBYTES , must be a power of two, and is computed as two raised to the power .Em MCLSHIFT . On systems with Ethernet network adapters, .Em MCLSHIFT is often set to 11, giving 2048-byte mbuf clusters, large enough to hold a 1500-byte Ethernet frame in a single cluster. Systems with network interfaces supporting larger frame sizes like ATM, FDDI, or HIPPI may perform better with .Em MCLSHIFT set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, respectively. .It Cd options NETATALK Include support for the AppleTalk protocol stack. The kernel provides provision for the .Em Datagram Delivery Protocol (DDP), providing SOCK_DGRAM support and AppleTalk routing. This stack is used by the .Em NETATALK package, which adds support for AppleTalk server services via user libraries and applications. .It Cd options BLUETOOTH Include support for the Bluetooth protocol stack. See .Xr bluetooth 4 for details. .It Cd options IPNOPRIVPORTS Normally, only root can bind a socket descriptor to a so-called .Dq privileged TCP port, that is, a port number in the range 0-1023. This option eliminates those checks from the kernel. This can be useful if there is a desire to allow daemons without privileges to bind those ports, e.g., on firewalls. The security tradeoffs in doing this are subtle. This option should only be used by experts. .It Cd options TCP_DEBUG Record the last .Em TCP_NDEBUG TCP packets with SO_DEBUG set, and decode to the console if .Em tcpconsdebug is set. .It Cd options TCP_NDEBUG Number of packets to record for .Em TCP_DEBUG . Defaults to 100. .It Cd options TCP_SENDSPACE=value .It Cd options TCP_RECVSPACE=value These options set the max TCP window size to other sizes than the default. The TCP window sizes can be altered via .Xr sysctl 8 as well. .It Cd options TCP_INIT_WIN=value This option sets the initial TCP window size for non-local connections, which is used when the transmission starts. The default size is 1, but if the machine should act more aggressively, the initial size can be set to some other value. The initial TCP window size can be set via .Xr sysctl 8 as well. .It Cd options TCP_SIGNATURE Enable MD5 TCP signatures (RFC 2385) to protect BGP sessions. .It Cd options IPFILTER_LOG This option, in conjunction with .Em pseudo-device ipfilter , enables logging of IP packets using IP-Filter. .It Cd options IPFILTER_LOOKUP This option enables the IP-Filter .Xr ippool 8 functionality to be enabled. .It Cd options IPFILTER_COMPAT This option enables older IP-Filter binaries to work. .It Cd options IPFILTER_DEFAULT_BLOCK This option sets the default policy of IP-Filter. If it is set, IP-Filter will block packets by default. .It Cd options BRIDGE_IPF This option causes .Em bridge devices to use the IP and/or IPv6 filtering hooks, forming a link-layer filter that uses protocol-layer rules. This option assumes the presence of .Em pseudo-device ipfilter . .It Cd options MBUFTRACE This option can help track down mbuf leaks. When enabled, mbufs are tagged with the devices and protocols using them, which slightly decreases network performance. This additional information can be viewed with .Xr netstat 1 : .Dl Ic netstat Fl mssv Not all devices or protocols support this option. .El .Ss Sysctl Related Options .Bl -ohang .It Cd options SYSCTL_DISALLOW_CREATE Disallows the creation or deletion of nodes from the sysctl tree, as well as the assigning of descriptions to nodes that lack them, by any process. These operations are still available to kernel sub-systems, including loadable kernel modules. .It Cd options SYSCTL_DISALLOW_KWRITE Prevents processes from adding nodes to the sysctl tree that make existing kernel memory areas writable. Sections of kernel memory can still be read and new nodes that own their own data may still be writable. .It Cd options SYSCTL_DEBUG_SETUP Causes the SYSCTL_SETUP routines to print a brief message when they are invoked. This is merely meant as an aid in determining the order in which sections of the tree are created. .It Cd options SYSCTL_DEBUG_CREATE Prints a message each time .Fn sysctl_create , the function that adds nodes to the tree, is called. .It Cd options SYSCTL_INCLUDE_DESCR Causes the kernel to include short, human readable descriptions for nodes in the sysctl tree. The descriptions can be retrieved programmatically (see .Xr sysctl 3 ) , or by the sysctl binary itself (see .Xr sysctl 8 ) . The descriptions are meant to give an indication of the purpose and/or effects of a given node's value, not replace the documentation for the given subsystem as a whole. .El .Ss System V IPC Options .Bl -ohang .It Cd options SYSVMSG Includes support for .At V style message queues. See .Xr msgctl 2 , .Xr msgget 2 , .Xr msgrcv 2 , .Xr msgsnd 2 . .It Cd options SYSVSEM Includes support for .At V style semaphores. See .Xr semctl 2 , .Xr semget 2 , .Xr semop 2 . .It Cd options SEMMNI=value Sets the number of .At V style semaphore identifiers. The GENERIC config file for your port will have the default. .It Cd options SEMMNS=value Sets the number of .At V style semaphores in the system. The GENERIC config file for your port will have the default. .It Cd options SEMUME=value Sets the maximum number of undo entries per process for .At V style semaphores. The GENERIC config file for your port will have the default. .It Cd options SEMMNU=value Sets the number of undo structures in the system for .At V style semaphores. The GENERIC config file for your port will have the default. .It Cd options SYSVSHM Includes support for .At V style shared memory. See .Xr shmat 2 , .Xr shmctl 2 , .Xr shmdt 2 , .Xr shmget 2 . .It Cd options SHMMAXPGS=value Sets the maximum number of .At V style shared memory pages that are available through the .Xr shmget 2 system call. Default value is 1024 on most ports. See .Pa /usr/include/machine/vmparam.h for the default. .El .Ss VM Related Options .Bl -ohang .It Cd options NMBCLUSTERS=value The number of mbuf clusters the kernel supports. Mbuf clusters are MCLBYTES in size (usually 2k). This is used to compute the size of the kernel VM map .Em mb_map , which maps mbuf clusters. The default value is calculated from the amount of physical memory. Architectures without direct mapping also limit it based on the kmem_map size, which is used as backing store. Some archs limit the value with .Sq NMBCLUSTERS_MAX . See .Pa /usr/include/machine/param.h for those archs. This value can be accessed via the kern.mbuf.nmbclusters sysctl variable. Increase this value if you get .Dq mclpool limit reached messages. .It Cd options NMBCLUSTERS_MAX=value The upper limit of NMBCLUSTERS. .It Cd options NKMEMPAGES=value .It Cd options NKMEMPAGES_MIN=value .It Cd options NKMEMPAGES_MAX=value Size of kernel VM map .Em kmem_map , in PAGE_SIZE-sized chunks (the VM page size; this value may be read from the .Xr sysctl 8 variable .Em hw.pagesize ). This VM map is used to map the kernel malloc arena. The kernel attempts to auto-size this map based on the amount of physical memory in the system. Platform-specific code may place bounds on this computed size, which may be viewed with the .Xr sysctl 8 variable .Em vm.nkmempages . See .Pa /usr/include/machine/param.h for the default upper and lower bounds. The related options .Sq NKMEMPAGES_MIN and .Sq NKMEMPAGES_MAX allow the bounds to be overridden in the kernel configuration file. These options are provided in the event the computed value is insufficient resulting in an .Dq out of space in kmem_map panic. .It Cd options SB_MAX=value Sets the max size in bytes that a socket buffer is allowed to occupy. The default is 256k, but sometimes it needs to be increased, for example when using large TCP windows. This option can be changed via .Xr sysctl 8 as well. .It Cd options SOMAXKVA=value Sets the maximum size of kernel virtual memory that the socket buffers are allowed to use. The default is 16MB, but in situations where for example large TCP windows are used this value must also be increased. This option can be changed via .Xr sysctl 8 as well. .It Cd options BUFCACHE=value Size of the buffer cache as a percentage of total available RAM. Ignored if BUFPAGES is also specified. .It Cd options NBUF=value Sets the number of buffer headers available, i.e., the number of open files that may have a buffer cache entry. Each buffer header requires MAXBSIZE (machine dependent, but usually 65536) bytes. The default value is machine dependent, but is usually equal to the value of BUFPAGES. .It Cd options BUFPAGES=value These options set the number of pages available for the buffer cache. Their default value is a machine dependent value, often calculated as between 5% and 10% of total available RAM. .It Cd options MAXTSIZ=bytes Sets the maximum size limit of a process' text segment. See .Pa /usr/include/machine/vmparam.h for the port-specific default. .It Cd options DFLDSIZ=bytes Sets the default size limit of a process' data segment, the value that will be returned as the soft limit for .Dv RLIMIT_DATA (as returned by .Xr getrlimit 2 ) . See .Pa /usr/include/machine/vmparam.h for the port-specific default. .It Cd options MAXDSIZ=bytes Sets the maximum size limit of a process' data segment, the value that will be returned as the hard limit for .Dv RLIMIT_DATA (as returned by .Xr getrlimit 2 ) . See .Pa /usr/include/machine/vmparam.h for the port-specific default. .It Cd options DFLSSIZ=bytes Sets the default size limit of a process' stack segment, the value that will be returned as the soft limit for .Dv RLIMIT_STACK (as returned by .Xr getrlimit 2 ) . See .Pa /usr/include/machine/vmparam.h for the port-specific default. .It Cd options MAXSSIZ=bytes Sets the maximum size limit of a process' stack segment, the value that will be returned as the hard limit for .Dv RLIMIT_STACK (as returned by .Xr getrlimit 2 ) . See .Pa /usr/include/machine/vmparam.h for the port-specific default. .It Cd options DUMP_ON_PANIC=integer Defaults to one. If set to zero, the kernel will not dump to the dump device when it panics, though dumps can still be forced via .Xr ddb 4 with the .Dq sync command. Note that this sets the value of the .Em kern.dump_on_panic .Xr sysctl 3 variable which may be changed at run time \(em see .Xr sysctl 8 for details. .It Cd options USE_TOPDOWN_VM User space memory allocations (as made by .Xr mmap 2 ) will be arranged in a .Dq top down fashion instead of the traditional .Dq upwards from MAXDSIZ \&+ vm_daddr method. This includes the placement of .Xr ld.so 1 . Arranging memory in this manner allows either (or both of) the heap or .Xr mmap 2 allocated space to grow larger than traditionally possible. This option is not available on all ports, but is instead expected to be offered on a port-by-port basis, after which some ports will commit to using it by default. See the files .Pa /usr/include/uvm/uvm_param.h for some implementation details, and .Pa /usr/include/machine/vmparam.h for port specific details including availability. .It Cd options VMSWAP Enable paging device/file support. This option is on by default. .It Cd options PDPOLICY_CLOCKPRO Use CLOCK-Pro, an alternative page replace policy. .El .Ss Security Options .Bl -ohang .It Cd options INSECURE Initializes the kernel security level with \-1 instead of 0. This means that the system always starts in secure level \-1 mode, even when running multiuser, unless the securelevel variable is set to value > \-1 in .Pa /etc/rc.conf . In this case the kernel security level will be raised to that value when the .Pa /etc/rc.d/securelevel script is run during system startup. See the manual page for .Xr init 8 for details on the implications of this. The kernel secure level may manipulated by the superuser by altering the .Em kern.securelevel .Xr sysctl 3 variable (the secure level may only be lowered by a call from process ID 1, i.e., .Xr init 8 ) . See also .Xr secmodel_securelevel 9 , .Xr sysctl 8 and .Xr sysctl 3 . .It Cd options VERIFIED_EXEC_FP_SHA256 Enables support for SHA256 hashes in Veriexec. .It Cd options VERIFIED_EXEC_FP_SHA384 Enables support for SHA384 hashes in Veriexec. .It Cd options VERIFIED_EXEC_FP_SHA512 Enables support for SHA512 hashes in Veriexec. .It Cd options PAX_MPROTECT=value Enables PaX MPROTECT, .Xr mprotect 2 restrictions from the PaX project. .Pp The .Ar value is the default value for the .Em global knob, see .Xr sysctl 3 . If 0, PaX MPROTECT will be enabled only if explicitly set on programs using .Xr paxctl 8 . If 1, PaX MPROTECT will be enabled for all programs. Programs can be exempted using .Xr paxctl 8 . .Pp See .Xr security 7 for more details. .It Cd options PAX_SEGVGUARD=value Enables PaX Segvguard. Requires .Cd options FILEASSOC . .Pp The .Ar value is the default value for the .Em global knob, see .Xr sysctl 3 . If 0, PaX Segvguard will be enabled only if explicitly set on programs using .Xr paxctl 8 . If 1, PaX Segvguard will be enabled to all programs, and exemption can be done using .Xr paxctl 8 . .Pp See .Xr security 7 for more details. .It Cd options PAX_ASLR=value Enables PaX ASLR. .Pp The .Ar value is the default value for the .Em global knob, see .Xr sysctl 3 . If 0, PaX ASLR will be enabled only if explicitly set on programs using .Xr paxctl 8 . If 1, PaX ASLR will be enabled to all programs, and exemption can be done using .Xr paxctl 8 . .Pp See .Xr security 7 for more details. .It Cd options USER_VA0_DISABLE_DEFAULT=value Sets the initial value of the flag which controls whether user programs can map virtual address 0. The flag can be changed at runtime by .Xr sysctl 3 . .It Cd options KASAN Enables Kernel Address Sanitizer. Should not be used in conjunction with KLEAK. .Em NOTE : not available on all architectures. .It Cd options KASLR Enables Kernel ASLR. This randomizes the location of the kernel image in memory. .Em NOTE : not available on all architectures. .It Cd options KLEAK Enables the KLEAK feature, that allows to detect kernel information leaks. Should not be used in conjunction with KASAN. .Em NOTE : not available on all architectures. .It Cd options SVS Enables Separate Virtual Space. On architectures that are designed to function with a shared address space, this option explicitly isolates the kernel and user spaces. .Em NOTE : not available on all architectures. .El .Ss amiga-specific Options .Bl -ohang .It Cd options BB060STUPIDROM When the bootloader (which passes AmigaOS ROM information) claims we have a 68060 CPU without FPU, go look into the Processor Configuration Register (PCR) to find out. You need this with Amiga ROMs up to (at least) V40.xxx (OS3.1), when you boot via the bootblocks and don't have a DraCo. .It Cd options IOBZCLOCK=frequency The IOBlix boards come with two different serial master clocks: older ones use 24 MHz, newer ones use 22.1184 MHz. The driver normally assumes the latter. If your board uses 24 MHz, you can recompile your kernel with options IOBZCLOCK=24000000 or patch the kernel variable iobzclock to the same value. .It Cd options LIMITMEM=value If there, limit the part of the first memory bank used by .Nx to value megabytes. Default is unlimited. .It Cd options P5PPC68KBOARD Add special support for Phase5 mixed 68k+PPC boards. Currently, this only affects rebooting from .Nx and is only needed on 68040+PPC, not on 68060+PPC; without this, affected machines will hang after .Nx has shut down and will only restart after a keyboard reset or a power cycle. .El .Ss atari-specific Options .Bl -ohang .It Cd options DISKLABEL_AHDI Include support for AHDI (native Atari) disklabels. .It Cd options DISKLABEL_NBDA Include support for .Nx Ns /atari labels. If you don't set this option, it will be set automatically. .Nx Ns /atari will not work without it. .It Cd options FALCON_SCSI Include support for the 5380-SCSI configuration as found on the Falcon. .It Cd options RELOC_KERNEL If set, the kernel will relocate itself to TT-RAM, if possible. This will give you a slightly faster system. .Em Beware that on some TT030 systems, the system will frequently dump with MMU-faults with this option enabled. .It Cd options SERCONSOLE Allow the modem1-port to act as the system-console. A carrier should be active on modem1 during system boot to active the console functionality. .It Cd options TT_SCSI Include support for the 5380-SCSI configuration as found on the TT030 and Hades. .El .Ss i386-specific Options .Bl -ohang .It Cd options CPURESET_DELAY=value Specifies the time (in millisecond) to wait before doing a hardware reset in the last phase of a reboot. This gives the user a chance to see error messages from the shutdown operations (like NFS unmounts, buffer cache flush, etc ...). Setting this to 0 will disable the delay. Default is 2 seconds. .It Cd options USER_LDT Include i386-specific system calls for modifying the local descriptor table, used by Windows emulators. .It Cd options PAE Enable PAE (Physical Address Extension) mode. PAE permits up to 36 bits physical addressing (64GB of physical memory), and turns physical addresses to 64 bits entities in the memory management subsystem. Userland virtual address space remains at 32 bits (4GB). PAE mode is required to enable the NX/XD (No-eXecute/eXecute Disable) bit for pages, which allows marking certain ones as not being executable. Any attempt to execute code from such a page will raise an exception. .It Cd options REALBASEMEM=integer Overrides the base memory size passed in from the boot block. (Value given in kilobytes.) Use this option only if the boot block reports the size incorrectly. (Note that some BIOSes put the extended BIOS data area at the top of base memory, and therefore report a smaller base memory size to prevent programs overwriting it. This is correct behavior, and you should not use the .Em REALBASEMEM option to access this memory). .It Cd options SPECTRE_V2_GCC_MITIGATION=1 Enable GCC-specific Spectre variant 2 mitigations. For 32-bit kernels this means these options: .Bd -literal -offset indent -mindirect-branch=thunk -mindirect-branch-register .Ed .Pp For 64-bit kernels this means these options: .Bd -literal -offset indent -mindirect-branch=thunk-inline -mindirect-branch-register .Ed .It Cd options REALEXTMEM=integer Overrides the extended memory size passed in from the boot block. (Value given in kilobytes. Extended memory does not include the first megabyte.) Use this option only if the boot block reports the size incorrectly. .It Cd options CYRIX_CACHE_WORKS Relevant only to the Cyrix 486DLC CPU. This option is used to turn on the cache in hold-flush mode. It is not turned on by default because it is known to have problems in certain motherboard implementations. .It Cd options CYRIX_CACHE_REALLY_WORKS Relevant only to the Cyrix 486DLC CPU. This option is used to turn on the cache in write-back mode. It is not turned on by default because it is known to have problems in certain motherboard implementations. In order for this option to take effect, option .Em CYRIX_CACHE_WORKS must also be specified. .It Cd options PCIBIOS Enable support for initializing the PCI bus using information from the BIOS. See .Xr pcibios 4 for details. .It Cd options MTRR Include support for accessing MTRR registers from user-space. See .Xr i386_get_mtrr 2 . .It Cd options BEEP_ONHALT Make the system speaker emit several beeps when it is completely safe to power down the computer after a .Xr halt 8 command. Requires .Xr sysbeep 4 support. .It Cd options BEEP_ONHALT_COUNT=times Number of times to beep the speaker when .Cd options BEEP_ONHALT is enabled. Defaults to 3. .It Cd options BEEP_ONHALT_PITCH=hz The tone frequency used when .Cd options BEEP_ONHALT option, in hertz. Defaults to 1500. .It Cd options BEEP_ONHALT_PERIOD=msecs The duration of each beep when .Cd options BEEP_ONHALT is enabled, in milliseconds. Defaults to 250. .It Cd options MULTIBOOT Makes the kernel Multiboot-compliant, allowing it to be booted through a Multiboot-compliant boot manager such as GRUB. See .Xr multiboot 8 for more information. .It Cd options SPLASHSCREEN Display a splash screen during boot. .El .Ss isa-specific Options Options specific to .Xr isa 4 busses. .Bl -ohang .It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size Control the section of IO bus space used for PCMCIA bus space mapping. Ideally the probed defaults are satisfactory, however in practice that is not always the case. See .Xr pcmcia 4 for details. .It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask Controls the allowable interrupts that may be used for PCMCIA devices. This mask is a logical-or of power-of-2s of allowable interrupts: .Bd -literal -offset 04n .Em "IRQ Val IRQ Val IRQ Val IRQ Val" 0 0x0001 4 0x0010 8 0x0100 12 0x1000 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2 0x0004 6 0x0040 10 0x0400 14 0x4000 3 0x0008 7 0x0080 11 0x0800 15 0x8000 .Ed .It Cd options PCKBC_CNATTACH_SELFTEST Perform a self test of the keyboard controller before attaching it as a console. This might be necessary on machines where we boot on cold iron, and pckbc refuses to talk until we request a self test. Currently only the netwinder port uses it. .It Cd options PCKBD_CNATTACH_MAY_FAIL If this option is set the PS/2 keyboard will not be used as the console if it cannot be found during boot. This allows other keyboards, like USB, to be the console keyboard. .It Cd options PCKBD_LAYOUT=layout Sets the default keyboard layout, see .Xr pckbd 4 . .El .Ss m68k-specific Options .Bl -ohang .It Cd options FPU_EMULATE Include support for MC68881/MC68882 emulator. .It Cd options FPSP Include support for 68040 floating point. .It Cd options M68020,M68030,M68040,M68060 Include support for a specific CPU, at least one (the one you are using) should be specified. .It Cd options M060SP Include software support for 68060. This provides emulation of unimplemented integer instructions as well as emulation of unimplemented floating point instructions and data types and software support for floating point traps. .El .Ss powerpc-specific Options (OEA Only) .Bl -ohang .It Cd options PMAP_MEMLIMIT=value Limit the amount of memory seen by the kernel to .Ar value bytes. .It Cd options PTEGCOUNT=value Specify the size of the page table as .Ar value PTE groups. Normally, one PTEG is allocated per physical page frame. .El .Ss sparc-specific Options .Bl -ohang .It Cd options AUDIO_DEBUG Enable simple event debugging of the logging of the .Xr audio 4 device. .It Cd options BLINK Enable blinking of LED. Blink rate is full cycle every N seconds for N < then current load average. See .Xr getloadavg 3 . .\" .It Cd options COLORFONT_CACHE .\" What does this do? .It Cd options COUNT_SW_LEFTOVERS Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover variables accessible from .Xr ddb 4 . See .Xr sw 4 . .It Cd options DEBUG_ALIGN Adds debugging messages calls when user-requested alignment fault handling happens. .It Cd options DEBUG_EMUL Adds debugging messages calls for emulated floating point and alignment fixing operations. .It Cd options EXTREME_DEBUG Adds debugging functions callable from .Xr ddb 4 . The debug_pagetables, test_region and print_fe_map functions print information about page tables for the SUN4M platforms only. .It Cd options EXTREME_EXTREME_DEBUG Adds extra info to .Em options EXTREME_DEBUG . .It Cd options FPU_CONTEXT Make .Em options COMPAT_SVR4 getcontext and setcontext include floating point registers. .It Cd options MAGMA_DEBUG Adds debugging messages to the .Xr magma 4 device. .It Cd options RASTERCONS_FULLSCREEN Use the entire screen for the console. .It Cd options RASTERCONS_SMALLFONT Use the Fixed font on the console, instead of the normal font. .It Cd options SUN4 Support sun4 class machines. .It Cd options SUN4C Support sun4c class machines. .It Cd options SUN4M Support sun4m class machines. .It Cd options SUN4_MMU3L .\" XXX ??? Enable support for sun4 3-level MMU machines. .It Cd options V9 Enable SPARC V9 assembler in .Xr ddb 4 . .El .Ss sparc64-specific Options .Bl -ohang .It Cd options AUDIO_DEBUG Enable simple event debugging of the logging of the .Xr audio 4 device. .It Cd options BLINK Enable blinking of LED. Blink rate is full cycle every N seconds for N < then current load average. See .Xr getloadavg 3 . .El .Ss x68k-specific Options .Bl -ohang .It Cd options EXTENDED_MEMORY Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. .It Cd options JUPITER Include support for Jupiter-X MPU accelerator .It Cd options ZSCONSOLE,ZSCN_SPEED=value Use the built-in serial port as the system-console. Speed is specified in bps, defaults to 9600. .It Cd options ITE_KERNEL_ATTR=value Set the kernel message attribute for ITE. Value, an integer, is a logical or of the following values: .Bl -tag -width 4n -compact -offset indent .It 1 color inversed .It 2 underlined .It 4 bolded .El .El .Ss x86-specific Options .Bl -ohang .It Cd options NO_PCI_MSI_MSIX Disable support for MSI/MSIX in the kernel. See .Xr pci_msi 9 for details of MSI/MSIX support .It Cd options NO_PREEMPTION Disables .Xr kpreempt 9 support in the kernel. .El .\" The following requests should be uncommented and used where appropriate. .\" .Sh FILES .\" .Sh EXAMPLES .Sh SEE ALSO .Xr config 1 , .Xr gcc 1 , .Xr gdb 1 , .Xr ktrace 1 , .Xr quota 1 , .Xr vndcompress 1 , .Xr gettimeofday 2 , .Xr i386_get_mtrr 2 , .Xr i386_iopl 2 , .Xr msgctl 2 , .Xr msgget 2 , .Xr msgrcv 2 , .Xr msgsnd 2 , .Xr ntp_adjtime 2 , .Xr ntp_gettime 2 , .Xr reboot 2 , .Xr semctl 2 , .Xr semget 2 , .Xr semop 2 , .Xr shmat 2 , .Xr shmctl 2 , .Xr shmdt 2 , .Xr shmget 2 , .Xr sysctl 3 , .Xr apm 4 , .Xr ddb 4 , .Xr inet 4 , .Xr md 4 , .Xr pcibios 4 , .Xr pcmcia 4 , .Xr ppp 4 , .Xr userconf 4 , .Xr vnd 4 , .Xr wscons 4 , .Xr config 5 , .Xr edquota 8 , .Xr init 8 , .Xr mdsetimage 8 , .Xr mount_cd9660 8 , .Xr mount_fdesc 8 , .Xr mount_kernfs 8 , .Xr mount_lfs 8 , .Xr mount_mfs 8 , .Xr mount_msdos 8 , .Xr mount_nfs 8 , .Xr mount_ntfs 8 , .Xr mount_null 8 , .Xr mount_portal 8 , .Xr mount_procfs 8 , .Xr mount_udf 8 , .Xr mount_umap 8 , .Xr mount_union 8 , .Xr mrouted 8 , .Xr newfs_lfs 8 , .Xr ntpd 8 , .Xr quotaon 8 , .Xr rpc.rquotad 8 , .Xr sysctl 8 , .Xr in_getifa 9 , .Xr kernhist 9 .Sh HISTORY The .Nm man page first appeared in .Nx 1.3 .