1.\" $NetBSD: options.4,v 1.255 2004/12/08 18:33:32 peter Exp $ 2.\" 3.\" Copyright (c) 1996 4.\" Perry E. Metzger. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgment: 16.\" This product includes software developed for the NetBSD Project 17.\" by Perry E. Metzger. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31.\" 32.\" 33.Dd November 11, 2004 34.Os 35.Dt OPTIONS 4 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 8 55for information on how to configure and build kernels. 56.Pp 57The 58.Ar no 59form removes a previously specified option. 60.Ss Keywords 61The following keywords are recognized in a kernel configuration file: 62.Bl -ohang 63.It Sy cinclude Xo 64.Qq Ar filename 65.Xc 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 Xo 72.Ar exec_name 73.No root on 74.Ar rootdev 75.Op type Ar fstype 76.Op dumps on Ar dumpdev 77.Xc 78Defines a configuration whose kernel executable is named 79.Ar exec_name , 80normally 81.Dq netbsd , 82with its root file system of type 83.Ar fstype 84on the device 85.Ar rootdev , 86and optionally specifying the location of kernel core dumps on the device 87.Ar dumpdev . 88.Ar dev 89or 90.Ar dumpdev 91and 92.Ar fstype 93may be specified as 94.Dq \&? , 95which is a wild card. 96The root 97.Ar fstype 98and 99.Ar dumpdev 100are optional and assumed to be wild carded if they are not specified. 101.It Ar device_instance Xo 102at 103.Ar attachment 104.Op Ar locators value Op ... 105.Op flags Ar value 106.Xc 107Define an instance of the device driver 108.Ar device_instance 109that attaches to the bus or device named 110.Ar attachment . 111An 112.Ar attachment 113may require additional information on where the device can be found, such 114as an address, channel, function, offset, and/or slot, referred to as 115.Ar locators , 116whose 117.Ar value 118often may be a wild card, 119.Dq \&? . 120Some device drivers have one or more 121.Ar flags 122that can be adjusted to affect the way they operate. 123.It Sy file-system Xo 124.Ar fs_name Op , Ar fs_name Op ... 125.Xc 126Include support for the file-system 127.Ar fs_name . 128.It Sy ident Xo 129.Qq Ar string 130.Xc 131Sets the kernel identification string to 132.Ar string . 133.It Sy include Xo 134.Qq Ar filename 135.Xc 136Functions the same as 137.Ar cinclude , 138except failure to open 139.Ar filename 140produces a fatal error. 141.It Sy options Xo 142.Ar option_name Op , Ar option_name=value Op ... 143.Xc 144Specifies (or sets) the option, or comma-separated list of options, 145.Ar option_name . 146Some options expect to be assigned a value, which may be an integer, 147a double-quoted word, a bare word, or an empty string 148.Pq Qq . 149.Pp 150.Em Note : 151Options that are not defined by device definition files are passed to 152the compile process as 153.Fl D 154flags to the C compiler. 155.It Sy makeoptions Xo 156.Ar name=value 157.Xc 158Defines a 159.Xr make 1 160macro 161.Ar name 162with the value 163.Ar value 164in the kernel Makefile. 165.It Sy maxusers Xo 166.Ar integer 167.Xc 168Set the maxusers variable in the kernel. 169.It Sy no Xo 170.Ar keyword Ar name Op Ar arguments Op ... 171.Xc 172For the 173.Xr config 8 174.Ar keywords 175file-system, makeoptions, options, and pseudo-device, 176.Ar no 177removes the file-system, makeoption, options, or pseudo-device, 178.Ar name . 179This is useful when a kernel configuration file includes another which 180has undesired options. 181.Pp 182For example, a local configuration file that wanted the kitchen sink, but 183not COMPAT_09 or bridging, might be: 184.Bd -literal -offset indent 185include "arch/i386/conf/GENERIC" 186no options COMPAT_09 187no pseudo-device bridge 188.Ed 189.It Sy pseudo-device Xo 190.Ar name 191.Op Ar N 192.Xc 193Includes support for the pseudo-device 194.Ar name . 195Some pseudo-devices can have multiple or 196.Ar N 197instances. 198.El 199.Ss Compatibility Options 200.Bl -ohang 201.It Cd options COMPAT_09 202Enable binary compatibility with 203.Nx 0.9 . 204This enables support for 20516-bit user, group, and process IDs (following revisions support 20632-bit identifiers), 207It also allows the use of the deprecated 208.Xr getdomainname 3 , 209.Xr setdomainname 3 , 210and 211.Xr uname 3 212syscalls. 213This option also allows using numeric file system identifiers rather 214than strings. 215Post 216.Nx 0.9 217versions use string identifiers. 218.It Cd options COMPAT_10 219Enable binary compatibility with 220.Nx 1.0 . 221This option allows the use of the file system name of 222.Dq ufs 223as an alias for 224.Dq ffs . 225The name 226.Dq ffs 227should be used post 1.0 in 228.Pa /etc/fstab 229and other files. 230It also adds old syscalls for the 231.At V 232shared memory interface. 233This was changed post 1.0 to work on 64-bit architectures. 234This option also enables 235.Dq sgtty 236compatibility, without which programs using the old interface produce 237an 238.Dq inappropriate ioctl 239error, and 240.Pa /dev/io 241only works when this option is set in the kernel, 242see 243.Xr io 4 244on ports that support it. 245.It Cd options COMPAT_11 246Enable binary compatibility with 247.Nx 1.1 . 248This allows binaries running on the i386 port to gain direct access to 249the io ports by opening 250.Pa /dev/io 251read/write. 252This functionality was replaced by 253.Xr i386_iopl 2 254post 1.1. 255On the 256.Tn Atari 257port, the location of the disk label was moved after 1.1. 258When the 259.Em COMPAT_11 260option is set, the kernel will read (pre) 1.1 style disk labels as a 261last resort. 262When a disklabel is re-written, the old style label will be replaced 263with a post 1.1 style label. 264This also enables the 265.Em EXEC_ELF_NOTELESS 266option. 267.It Cd options COMPAT_12 268Enable binary compatibility with 269.Nx 1.2 . 270This allows the use of old syscalls for 271.Fn reboot 272and 273.Fn swapon . 274The syscall numbers were changed post 1.2 to add functionality to the 275.Xr reboot 2 276syscall, and the new 277.Xr swapctl 2 278interface was introduced. 279This also enables the 280.Em EXEC_ELF_NOTELESS 281option. 282.It Cd options COMPAT_13 283Enable binary compatibility with 284.Nx 1.3 . 285This allows the use of old syscalls for 286.Fn sigaltstack , 287and also enables the old 288.Xr swapctl 2 289command 290.Dv SWAP_STATS 291(now called 292.Dv SWAP_OSTATS ) , 293which does not include the 294.Fa se_path 295member of 296.Va struct swapent . 297.It Cd options COMPAT_14 298Enable binary compatibility with 299.Nx 1.4 . 300This allows some old 301.Xr ioctl 2 302on 303.Xr wscons 4 304to be performed, and allows the 305.Dv NFSSVC_BIOD 306mode of the 307.Xr nfssvc 2 308system call to be used for compatibility with the deprecated nfsiod program. 309.It Cd options COMPAT_16 310Enable binary compatibility with 311.Nx 1.6 . 312This allows the use of old signal trampoline code which has been deprecated 313with the addition of 314.Xr siginfo 5 . 315.It Cd options COMPAT_43 316Enables compatibility with 317.Bx 4.3 . 318This adds an old syscall for 319.Xr lseek 2 . 320It also adds the ioctls for 321.Dv TIOCGETP 322and 323.Dv TIOCSETP . 324The return values for 325.Xr getpid 2 , 326.Xr getgid 2 , 327and 328.Xr getuid 2 329syscalls are modified as well, to return the parent's PID and 330UID as well as the current process's. 331It also enables the deprecated 332.Dv NTTYDISC 333terminal line discipline. 334It also provides backwards compatibility with 335.Dq old 336SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 337binary compatibility with code written before the introduction of the 338sa_len field in sockaddrs. 339It also enables 340support for some older pre 341.Bx 4.4 342socket calls. 343.It Cd options COMPAT_BSDPTY 344This option is currenty on by default and enables the pty multiplexor 345.Xr ptm 4 346and 347.Xr ptmx 4 348to find and use ptys named 349.Pa /dev/ptyXX 350(master) and 351.Pa /dev/ttyXX 352(slave). 353Eventually this option will become optional as ptyfs based pseudo-ttys become 354the default, see 355.Xr mount_ptyfs 8 . 356.It Cd options COMPAT_SVR4 357On those architectures that support it, this enables binary 358compatibility with 359.At V.4 360applications built for the same architecture. 361This currently includes the i386, m68k, and sparc ports. 362.It Cd options COMPAT_LINUX 363On those architectures that support it, this enables binary 364compatibility with Linux ELF and 365.Xr a.out 5 366applications built for the same architecture. 367This currently includes the alpha, arm, i386, m68k, mips, and powerpc 368ports. 369.It Cd options COMPAT_SUNOS 370On those architectures that support it, this enables binary 371compatibility with 372.Tn SunOS 4.1 373applications built for the same architecture. 374This currently includes the sparc, sparc64 and most or all m68k ports. 375Note that the sparc64 requires the 376.Em COMPAT_NETBSD32 377option for 64-bit kernels, in addition to this option. 378.It Cd options COMPAT_ULTRIX 379On those architectures that support it, this enables binary 380compatibility with 381.Tn ULTRIX 382applications built for the same architecture. 383This currently is limited to the pmax. 384The functionality of this option is unknown. 385.It Cd options COMPAT_DARWIN 386On those architectures that support it, this enables binary compatibility with 387.Tn Darwin 388applications built for the same architecture. 389This feature is highly experimental, it requires COMPAT_MACH and 390EXEC_MACHO and it is currently limited to i386 and powerpc ports of 391.Nx . 392.It Cd options COMPAT_FREEBSD 393On those architectures that support it, this enables binary 394compatibility with 395.Fx 396applications built for the same architecture. 397At the moment this is limited to the i386 port. 398.It Cd options COMPAT_HPUX 399On those architectures that support it, this enables binary 400compatibility with 401.Tn HP/UX 402applications built for the same architecture. 403This is limited to the hp300 port, and has some known bugs. 404A limited set of programs do work. 405.It Cd options COMPAT_IBCS2 406On those architectures that support it, this enables binary 407compatibility with iBCS2 or SVR3 applications built for the same architecture. 408This is currently limited to the i386 and vax ports. 409.It Cd options COMPAT_IRIX 410On those architectures that support it, this enables binary 411compatibility with IRIX o32 binaries built for the same architecture. 412This feature is experimental, and it is currently limited to 413the sgimips port. 414.It Cd options COMPAT_MACH 415On those architectures that support it, this enables the emulation of 416Mach kernel traps for binaries built for the same architecture. 417This features is highly experimental and it is currently 418limited to i386 and powerpc ports of 419.Nx . 420.It Cd options COMPAT_OSF1 421On those architectures that support it, this enables binary 422compatibility with 423.Tn Digital 424.Ux 425.Po 426formerly 427.Tn OSF/1 428.Pc 429applications built for the same architecture. 430This is currently limited to the alpha port. 431.It Cd options COMPAT_NOMID 432Enable compatibility with 433.Xr a.out 5 434executables that lack a machine ID. 435This includes 436.Nx 0.8 Ns 's 437ZMAGIC format, and 386BSD and BSDI's 438QMAGIC, NMAGIC, and OMAGIC 439.Xr a.out 5 440formats. 441.It Cd options COMPAT_NETBSD32 442On those architectures that support it, this enables binary 443compatibility with 32-bit applications built for the same architecture. 444This is currently limited to the amd64 and sparc64 ports, and only 445applicable for 64-bit kernels. 446.It Cd options COMPAT_SVR4_32 447On those architectures that support it, this enables binary 448compatibility with 32-bit SVR4 applications built for the same architecture. 449This is currently limited to the sparc64 port, and only applicable for 45064-bit kernels. 451.It Cd options COMPAT_AOUT_M68K 452On m68k architectures which have switched to ELF, 453this enable binary compatibility with 454.Nx Ns Tn /m68k 455.Xr a.out 5 456executables on 457.Nx Ns Tn /m68k 458ELF kernel. 459This handles alignment incompatibility of m68k ABI between 460a.out and ELF which causes the structure padding differences. 461Currently only some system calls which use 462.Va struct stat 463are adjusted and some binaries which use 464.Xr sysctl 3 465to retrieve network details would not work properly. 466.It Cd options EXEC_MACHO 467On those architectures that support it, this adds support for running 468Mach-O executables. 469This is currently limited to the i386 and powerpc ports of 470.Nx . 471.It Cd options EXEC_ELF_NOTELESS 472Run unidentified ELF binaries as 473.Nx 474binaries. 475This might be needed for very old 476.Nx 477ELF binaries on some archs. 478These old binaries didn't contain an appropriate 479.Li .note.netbsd.ident 480section, and thus can't be identified by the kernel as 481.Nx 482binaries otherwise. 483Beware - if this option is on, the kernel would run 484.Em any 485unknown ELF binaries as if they were 486.Nx 487binaries. 488.El 489.Ss Debugging Options 490.Bl -ohang 491.It Cd options DDB 492Compiles in a kernel debugger for diagnosing kernel problems. 493See 494.Xr ddb 4 495for details. 496.Em NOTE : 497not available on all architectures. 498.It Cd options DDB_FROMCONSOLE=integer 499If set to non-zero, DDB may be entered by sending a break on a serial 500console or by a special key sequence on a graphics console. 501A value of "0" ignores console breaks or key sequences. 502If not explicitly specified, the default value is "1". 503Note that this sets the value of the 504.Em ddb.fromconsole 505.Xr sysctl 3 506variable which may be changed at run time -- see 507.Xr sysctl 8 508for details. 509.It Cd options DDB_HISTORY_SIZE=integer 510If this is non-zero, enable history editing in the kernel debugger 511and set the size of the history to this value. 512.It Cd options DDB_ONPANIC 513If set to non-zero, DDB will be entered upon kernel panic. 514The default if not specified is "1". 515Note that this sets the value of the 516.Em ddb.onpanic 517.Xr sysctl 3 518variable which may be changed at run time -- see 519.Xr sysctl 8 520for details. 521.It Cd options DDB_BREAK_CHAR=integer 522This option overrides the using break to enter the kernel debugger 523on the serial console. 524The value given will is the ascii value to be used instead. 525This is currently only supported by the com driver. 526.It Cd options KGDB 527Compiles in a remote kernel debugger stub for diagnosing kernel problems 528using the 529.Dq remote target 530feature of gdb. 531See 532.Xr gdb 1 533for details. 534.Em NOTE : 535not available on all architectures. 536.It Cd options KGDB_DEV 537Device number 538.Po 539as a 540.Dv dev_t 541.Pc 542of kgdb device. 543.It Cd options KGDB_DEVADDR 544Memory address of kgdb device. 545.It Cd options KGDB_DEVMODE 546Permissions of kgdb device. 547.It Cd options KGDB_DEVNAME 548Device name of kgdb device. 549.It Cd options KGDB_DEVRATE 550Baud rate of kgdb device. 551.It Cd makeoptions DEBUG="-g" 552The 553.Fl g 554flag causes 555.Pa netbsd.gdb 556to be built in addition to 557.Pa netbsd . 558.Pa netbsd.gdb 559is useful for debugging kernel crash dumps with gdb. 560See 561.Xr gdb 1 562for details. 563This also turns on 564.Em options DEBUG 565(which see). 566.It Cd options DEBUG 567Turns on miscellaneous kernel debugging. 568Since options are turned into preprocessor defines (see above), 569.Em options DEBUG 570is equivalent to doing a 571.Em #define DEBUG 572throughout the kernel. 573Much of the kernel has 574.Em #ifdef DEBUG 575conditionalized debugging code. 576Note that many parts of the kernel (typically device drivers) include their own 577.Em #ifdef XXX_DEBUG 578conditionals instead. 579This option also turns on certain other options, 580which may decrease system performance. 581.It Cd options DIAGNOSTIC 582Adds code to the kernel that does internal consistency checks. 583This code will cause the kernel to panic if corruption of internal data 584structures is detected. 585These checks can decrease performance up to 15%. 586.It Cd options KSTACK_CHECK_MAGIC 587Check kernel stack usage and panic if stack overflow is detected. 588This check is performance sensitive because it scans stack on each context 589switch. 590.It Cd options KTRACE 591Add hooks for the system call tracing facility, which allows users to 592watch the system call invocation behavior of processes. 593See 594.Xr ktrace 1 595for details. 596.It Cd options MSGBUFSIZE=integer 597This option sets the size of the kernel message buffer. 598This buffer holds the kernel output of 599.Fn printf 600when not (yet) read by 601.Xr syslogd 8 . 602This is particularly useful when the system has crashed and you wish to lookup 603the kernel output from just before the crash. 604Also, since the autoconfig output becomes more and more verbose, 605it sometimes happens that the message buffer overflows before 606.Xr syslogd 8 607was able to read it. 608Note that not all systems are capable of obtaining a variable sized message 609buffer. 610There are also some systems on which memory contents are not preserved 611across reboots. 612.It Cd options MALLOCLOG 613Enables an event log for 614.Xr malloc 9 . 615Useful for tracking down 616.Dq Data modified on freelist 617and 618.Dq multiple free 619problems. 620.It Cd options MALLOCLOGSIZE=integer 621Defines the number of entries in the malloc log. 622Default is 100000 entries. 623.It Cd options SYSTRACE 624Add hooks for the system call policy facility. 625See 626.Xr systrace 1 627for details. 628.It Cd options UVMHIST 629Enables the UVM history logs, which create in-memory traces of 630various UVM activities. 631These logs can be displayed be calling 632.Fn uvmhist_dump 633or 634.Fn uvm_hist 635with appropriate arguments from DDB. 636See the kernel source file sys/uvm/uvm_stat.c for details. 637.It Cd options UVMHIST_PRINT 638Prints the UVM history logs on the system console as entries are added. 639Note that the output is 640.Em extremely 641voluminous, so this option is really only useful for debugging 642the very earliest parts of kernel initialization. 643.El 644.Ss File Systems 645.Bl -ohang 646.It Cd file-system FFS 647Includes code implementing the Berkeley Fast File System 648.Em ( FFS ) . 649Most machines need this if they are not running diskless. 650.It Cd file-system EXT2FS 651Includes code implementing the Second Extended File System 652.Em ( EXT2FS ) , 653revision 0 and revision 1 with the 654.Em filetype 655and 656.Em sparse_super 657options. 658This is the most commonly used file system on the Linux operating system, 659and is provided here for compatibility. 660Some of the specific features of 661.Em EXT2FS 662like the "behavior on errors" are not implemented. 663This file system can't be used with UID or GID greater than 65535. 664See 665.Xr mount_ext2fs 8 666for details. 667.It Cd file-system LFS 668.Em [EXPERIMENTAL] 669Include the Log-structured File System 670.Em ( LFS ) . 671See 672.Xr mount_lfs 8 673and 674.Xr newfs_lfs 8 675for details. 676.It Cd file-system MFS 677Include the Memory File System 678.Em ( MFS ) . 679This file system stores files in swappable memory, and produces 680notable performance improvements when it is used as the file store 681for 682.Pa /tmp 683and similar file systems. 684See 685.Xr mount_mfs 8 686for details. 687.It Cd file-system NFS 688Include the client side of the Network File System 689.Pq Tn NFS 690remote file sharing protocol. 691Although the bulk of the code implementing 692.Tn NFS 693is kernel based, several user level daemons are needed for it to work. 694See 695.Xr mount_nfs 8 696for details. 697.It Cd file-system CD9660 698Includes code for the 699.Tn ISO 7009660 + Rock Ridge file system, which is the standard file system on many 701.Tn CD-ROM 702discs. 703Useful primarily if you have a 704.Tn CD-ROM 705drive. 706See 707.Xr mount_cd9660 8 708for details. 709.It Cd file-system MSDOSFS 710Includes the 711.Tn MS-DOS 712FAT file system, which is reportedly still used 713by unfortunate people who have not heard about 714.Nx . 715Also implements the 716.Tn Windows 95 717extensions to the same, which permit the use of longer, mixed case 718file names. 719See 720.Xr mount_msdos 8 721and 722.Xr fsck_msdos 8 723for details. 724.It Cd file-system NTFS 725.Em [EXPERIMENTAL] 726Includes code for the 727.Tn Microsoft Windows NT 728file system. 729See 730.Xr mount_ntfs 8 731for details. 732.It Cd file-system FDESC 733Includes code for a file system, conventionally mounted on 734.Pa /dev/fd , 735which permits access to the per-process file descriptor space via 736special files in the file system. 737See 738.Xr mount_fdesc 8 739for details. 740Note that this facility is redundant, and thus unneeded on most 741.Nx 742systems, since the 743.Xr fd 4 744pseudo-device driver already provides identical functionality. 745On most 746.Nx 747systems, instances of 748.Xr fd 4 749are mknoded under 750.Pa /dev/fd/ 751and on 752.Pa /dev/stdin , 753.Pa /dev/stdout , 754and 755.Pa /dev/stderr . 756.It Cd file-system KERNFS 757Includes code which permits the mounting of a special file system 758(normally mounted on 759.Pa /kern ) 760in which files representing various kernel variables and parameters 761may be found. 762See 763.Xr mount_kernfs 8 764for details. 765.It Cd file-system NULLFS 766Includes code for a loopback file system. 767This permits portions of the file hierarchy to be re-mounted in other places. 768The code really exists to provide an example of a stackable file system layer. 769See 770.Xr mount_null 8 771for details. 772.It Cd file-system OVERLAY 773Includes code for a file system filter. 774This permits the overlay file system to intercept all access to an underlying 775file system. 776This file system is intended to serve as an example of a stacking file 777system which has a need to interpose itself between an underlying file 778system and all other access. 779See 780.Xr mount_overlay 8 781for details. 782.It Cd file-system PORTAL 783.Em [EXPERIMENTAL] 784Includes the portal file system. 785This permits interesting tricks like opening 786.Tn TCP 787sockets by opening files in the file system. 788The portal file system is conventionally mounted on 789.Pa /p 790and is partially implemented by a special daemon. 791See 792.Xr mount_portal 8 793for details. 794.It Cd file-system PROCFS 795Includes code for a special file system (conventionally mounted on 796.Pa /proc ) 797in which the process space becomes visible in the file system. 798Among 799other things, the memory spaces of processes running on the system are 800visible as files, and signals may be sent to processes by writing to 801.Pa ctl 802files in the procfs namespace. 803See 804.Xr mount_procfs 8 805for details. 806.It Cd file-system UMAPFS 807Includes a loopback file system in which user and group IDs may be 808remapped -- this can be useful when mounting alien file systems with 809different UIDs and GIDs than the local system. 810See 811.Xr mount_umap 8 812for details. 813.It Cd file-system UNION 814.Em [EXPERIMENTAL] 815Includes code for the union file system, which permits directories to 816be mounted on top of each other in such a way that both file systems 817remain visible -- this permits tricks like allowing writing (and the 818deleting of files) on a read-only file system like a 819.Tn CD-ROM 820by mounting a local writable file system on top of the read-only file system. 821See 822.Xr mount_union 8 823for details. 824.It Cd file-system CODA 825.Em [EXPERIMENTAL] 826Includes code for the Coda file system. 827Coda is a distributed file system like NFS and AFS. 828It is freely available, like NFS, but it functions much like AFS in being a 829.Dq stateful 830file system. 831Both Coda and AFS cache files on your local machine to improve performance. 832Then Coda goes a step further than AFS by letting you access the cached 833files when there is no available network, viz. disconnected laptops and 834network outages. 835In Coda, both the client and server are outside the kernel which makes 836them easier to experiment with. 837Coda is available for several UNIX and non-UNIX platforms. 838See http://www.coda.cs.cmu.edu for more details. 839NOTE: You also need to enable the pseudo-device, vcoda, for the Coda 840file system to work. 841.El 842.Ss File System Options 843.Bl -ohang 844.It Cd options NFSSERVER 845Include the server side of the 846.Em NFS 847(Network File System) remote file sharing protocol. 848Although the bulk of the code implementing 849.Em NFS 850is kernel based, several user level daemons are needed for it to 851work. 852See 853.Xr mountd 8 854and 855.Xr nfsd 8 856for details. 857.It Cd options QUOTA 858Enables kernel support for file system quotas. 859See 860.Xr quotaon 8 , 861.Xr edquota 8 , 862and 863.Xr quota 1 864for details. 865Note that quotas only work on 866.Dq ffs 867file systems, although 868.Xr rpc.rquotad 8 869permits them to be accessed over 870.Em NFS . 871.It Cd options FFS_EI 872Enable ``Endian-Independent'' FFS support. 873This allows a system to mount an FFS file system created for another 874architecture, at a small performance cost for all FFS file systems. 875See also 876.Xr newfs 8 , 877.Xr fsck_ffs 8 , 878.Xr dumpfs 8 879for file system byte order status and manipulation. 880.It Cd options NVNODE=integer 881This option sets the size of the cache used by the name-to-inode translation 882routines, (a.k.a. the 883.Fn namei 884cache, though called by many other names in the kernel source). 885By default, this cache has 886.Dv NPROC 887(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 888A reasonable way to derive a value of 889.Dv NVNODE , 890should you notice a large number of namei cache misses with a tool such as 891.Xr systat 1 , 892is to examine your system's current computed value with 893.Xr sysctl 8 , 894(which calls this parameter "kern.maxvnodes") and to increase this value 895until either the namei cache hit rate improves or it is determined that 896your system does not benefit substantially from an increase in the size of 897the namei cache. 898.It Cd options NAMECACHE_ENTER_REVERSE 899Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 900as well as a normal one. 901Normally, this is already done for directory vnodes, to speed up the getcwd 902operation. 903This option will cause longer hash chains in the reverse cache, and thus 904slow down getcwd somewhat. 905However, it does make vnode -\*[Gt] path translations possible in some cases. 906For now, only useful if strict /proc/#/maps emulation for Linux binaries is 907required. 908.It Cd options EXT2FS_SYSTEM_FLAGS 909This option changes the behavior of the APPEND and IMMUTABLE flags 910for a file on an 911.Em EXT2FS 912file system. 913Without this option, the superuser or owner of the file can 914set and clear them. 915With this option, only the superuser can set them, and 916they can't be cleared if the securelevel is greater than 0. 917See also 918.Xr chflags 1 . 919.It Cd options NFS_BOOT_BOOTP 920Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 921information if NFS is used to mount the root file system. 922See 923.Xr diskless 8 924for details. 925.It Cd options NFS_BOOT_DHCP 926Same as 927.Dq NFS_BOOT_BOOTP , 928but use the DHCP extensions to the 929BOOTP protocol (RFC 1541). 930.It Cd options NFS_BOOT_BOOTP_REQFILE 931Specifies the string sent in the bp_file field of the BOOTP / DHCP 932request packet. 933.It Cd options NFS_BOOT_BOOTPARAM 934Enable use of the BOOTPARAM protocol, consisting of RARP and 935BOOTPARAM RPC, to get configuration information if NFS 936is used to mount the root file system. 937See 938.Xr diskless 8 939for details. 940.It Cd options NFS_BOOT_RWSIZE=value 941Set the initial NFS read and write sizes for diskless-boot requests. 942The normal default is 8Kbytes. 943This option provides a way to lower the value (e.g., to 1024 bytes) 944as a workaround for buggy network interface cards or boot PROMs. 945Once booted, the read and write request sizes can be increased by 946remounting the file system. 947See 948.Xr mount_nfs 8 949for details. 950.It Cd options NFS_V2_ONLY 951Reduce the size of the NFS client code by omitting code that's only required 952for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 953servers. 954.El 955.Ss Miscellaneous Options 956.Bl -ohang 957.It Cd options NEW_BUFQ_STRATEGY 958Enable experimental buffer queue strategy for disk I/O. 959In the default strategy, outstanding disk requests are ordered by 960sector number and sent to the disk, regardless of whether the 961operation is a read or write; this option gives priority to issuing 962read requests over write requests. 963Although requests may therefore be issued out of sector-order, causing 964more seeks and thus lower overall throughput, interactive system 965responsiveness under heavy disk I/O load may be improved, as processes 966blocking on disk reads are serviced sooner (file writes typically 967don't cause applications to block). 968The performance effect varies greatly depending on the hardware, drive 969firmware, filesystem configuration, workload, and desired performance 970trade-off. 971Systems using drive write-cache (most modern IDE disks, by default) 972are unlikely to benefit and may well suffer; such disks acknowledge 973writes very quickly, and optimise them internally according to 974physical layout. 975Giving these disks as many requests to work with as possible (the 976standard strategy) will typically produce the best results, especially 977if the drive has a large cache; the drive will silently complete 978writes from cache as it seeks for reads. 979Disks that support a large number of concurrent tagged requests (SCSI 980disks and many hardware RAID controllers) expose this internal 981scheduling with tagged responses, and don't block for reads; such 982disks may not see a noticable difference with either strategy. 983However, if IDE disks are run with write-cache disabled for safety, 984writes are not acknowledged until actually completed, and only one 985request can be outstanding; a large number of small writes in one 986locality can keep the disk busy, starving reads elsewhere on the disk. 987Such systems are likely to see the most benefit from this option. 988Finally, the performance interaction of this option with ffs soft 989dependencies can be subtle, as that mechanism can drastically alter 990the workload for filesystem metadata writes. 991.It Cd options LKM 992Enable loadable kernel modules. 993See 994.Xr lkm 4 995for details. 996.Em NOTE : 997not available on all architectures. 998.It Cd options INSECURE 999Hardwires the kernel security level at -1. 1000This means that the system 1001always runs in secure level 0 mode, even when running multiuser. 1002See the manual page for 1003.Xr init 8 1004for details on the implications of this. 1005The kernel secure level may manipulated by the superuser by altering the 1006.Em kern.securelevel 1007.Xr sysctl 3 1008variable (the secure level may only be lowered by a call from process ID 1, 1009i.e. 1010.Xr init 8 ) . 1011See also 1012.Xr sysctl 8 1013and 1014.Xr sysctl 3 . 1015.It Cd options MEMORY_DISK_DYNAMIC 1016This options makes the 1017.Xr md 4 1018.Tn RAM 1019disk size dynamically sized. 1020.It Cd options MEMORY_DISK_HOOKS 1021This option allows for some machine dependent functions to be called when 1022the 1023.Xr md 4 1024.Tn RAM 1025disk driver is configured. 1026This can result in automatically loading a 1027.Tn RAM 1028disk from floppy on open (among other things). 1029.It Cd options MEMORY_DISK_IS_ROOT 1030Forces the 1031.Xr md 4 1032.Tn RAM 1033disk to be the root device. 1034This can only be overridden when 1035the kernel is booted in the 'ask-for-root' mode. 1036.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1037Allocates the given number of 512 byte blocks as memory for the 1038.Xr md 4 1039.Tn RAM 1040disk, to be populated with 1041.Xr mdsetimage 8 . 1042.It Cd options MEMORY_DISK_SERVER=0 1043Do not include the interface to a userland memory disk server process. 1044Per default, this options is set to 1, including the support code. 1045Useful for install media kernels. 1046.It Cd options VNODE_OP_NOINLINE 1047Do not inline the 1048.Fn VOP_* 1049calls in the kernel. 1050On i386 GENERIC, this saves 36k of kernel text. 1051Useful for install media kernels, small memory systems and embedded systems. 1052.It Cd options MALLOC_NOINLINE 1053Time critical fixed size memory allocation is performed with 1054.Fn MALLOC 1055and 1056.Fn FREE . 1057Normally these expand to inline code, but with 1058.Em MALLOC_NOINLINE 1059these call the normal 1060.Fn malloc 1061and 1062.Fn free 1063functions. 1064Useful for install media kernels, small memory systems and embedded systems. 1065.It Cd options HZ=integer 1066On ports that support it, set the system clock frequency (see 1067.Xr hz 9 ) 1068to the supplied value. 1069Handle with care. 1070.It Cd options NTP 1071Turns on in-kernel precision timekeeping support used by software 1072implementing 1073.Em NTP 1074(Network Time Protocol, RFC 1305). 1075The 1076.Em NTP 1077option adds an in-kernel Phase-Locked Loop (PLL) for normal 1078.Em NTP 1079operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1080operation. 1081.Xr ntpd 8 1082will employ a user-level PLL when kernel support is unavailable, 1083but the in-kernel version has lower latency and more precision, and 1084so typically keeps much better time. 1085The interface to the kernel 1086.Em NTP 1087support is provided by the 1088.Xr ntp_adjtime 2 1089and 1090.Xr ntp_gettime 2 1091system calls, which are intended for use by 1092.Xr ntpd 8 1093and are enabled by the option. 1094On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1095is not an integer, the 1096.Em NTP 1097option also enables extended-precision arithmetic to keep track of 1098fractional clock ticks at NTP time-format precision. 1099.It Cd options PPS_SYNC 1100This option enables a kernel serial line discipline for receiving time 1101phase signals from an external reference clock such as a radio clock. 1102(The 1103.Em NTP 1104option (which see) must be on if the 1105.Em PPS_SYNC 1106option is used.) 1107Some reference clocks generate a Pulse Per Second (PPS) signal in 1108phase with their time source. 1109The 1110.Em PPS 1111line discipline receives this signal on either the data leads 1112or the DCD control lead of a serial port. 1113.Em NTP 1114uses the PPS signal to discipline the local clock oscillator to a high 1115degree of precision (typically less than 50 microseconds in time and 11160.1 ppm in accuracy). 1117.Em PPS 1118can also generate a serial output pulse when the system receives a PPS 1119interrupt. 1120This can be used to measure the system interrupt latency and thus calibrate 1121.Em NTP 1122to account for it. 1123Using 1124.Em PPS 1125usually requires a 1126gadget box 1127to convert from TTL to RS-232 signal levels. 1128The gadget box and PPS are described in more detail in the HTML documentation 1129for 1130.Xr ntpd 8 1131in 1132.Pa /usr/share/doc/html/ntp . 1133.It Cd options NO_TSC_TIME 1134Don't use TSC microtime, even if available (i386 only). 1135Improves time behavior under VMware. 1136.It Cd options SETUIDSCRIPTS 1137Allows scripts with the setuid bit set to execute as the effective 1138user rather than the real user, just like binary executables. 1139.Pp 1140.Em NOTE : 1141Using this option will also enable 1142.Em options FDSCRIPTS 1143.It Cd options FDSCRIPTS 1144Allows execution of scripts with the execute bit set, but not the 1145read bit, by opening the file and passing the file descriptor to 1146the shell, rather than the filename. 1147.Pp 1148.Em NOTE : 1149Execute only (non-readable) scripts will have 1150.Va argv[0] 1151set to 1152.Pa /dev/fd/* . 1153What this option allows as far as security is 1154concerned, is the ability to safely ensure that the correct script 1155is run by the interpreter, as it is passed as an already open file. 1156.It Cd options PUCCN 1157Enables treating serial ports found on PCI boards 1158.Xr puc 4 1159as potential console devices. 1160The method for choosing such a console device is port dependent. 1161.It Cd options RTC_OFFSET=integer 1162The kernel (and typically the hardware battery backed-up clock on 1163those machines that have one) keeps time in 1164.Em UTC 1165(Universal Coordinated Time, once known as 1166.Em GMT , 1167or Greenwich Mean Time) 1168and not in the time of the local time zone. 1169The 1170.Em RTC_OFFSET 1171option is used on some ports (such as the i386) to tell the kernel 1172that the hardware clock is offset from 1173.Em UTC 1174by the specified number of minutes. 1175This is typically used when a machine boots several operating 1176systems and one of them wants the hardware clock to run in the 1177local time zone and not in 1178.Em UTC , 1179e.g. 1180.Em RTC_OFFSET=300 1181means 1182the hardware clock is set to US Eastern Time (300 minutes behind 1183.Em UTC ) , 1184and not 1185.Em UTC . 1186(Note: 1187.Em RTC_OFFSET 1188is used to initialize a kernel variable named 1189.Va rtc_offset 1190which is the source actually used to determine the clock offset, and 1191which may be accessed via the kern.rtc_offset sysctl variable. 1192See 1193.Xr sysctl 8 1194and 1195.Xr sysctl 3 1196for details. 1197Since the kernel clock is initialized from the hardware clock very 1198early in the boot process, it is not possible to meaningfully change 1199.Va rtc_offset 1200in system initialization scripts. 1201Changing this value currently may only be done at kernel compile 1202time or by patching the kernel and rebooting). 1203.Pp 1204.Em NOTE : 1205Unfortunately, in many cases where the hardware clock 1206is kept in local time, it is adjusted for Daylight Savings 1207Time; this means that attempting to use 1208.Em RTC_OFFSET 1209to let 1210.Nx 1211coexist with such an operating system, like Windows, 1212would necessitate changing 1213.Em RTC_OFFSET 1214twice a year. 1215As such, this solution is imperfect. 1216.It Cd options KMEMSTATS 1217The kernel memory allocator, 1218.Xr malloc 9 , 1219will keep statistics on its performance if this option is enabled. 1220Unfortunately, this option therefore essentially disables the 1221.Fn MALLOC 1222and 1223.Fn FREE 1224forms of the memory allocator, which are used to enhance the performance 1225of certain critical sections of code in the kernel. 1226This option therefore can lead to a significant decrease in the 1227performance of certain code in the kernel if enabled. 1228Examples of such code include the 1229.Fn namei 1230routine, the 1231.Xr ccd 4 1232driver, 1233the 1234.Xr ncr 4 1235driver, 1236and much of the networking code. 1237.It Cd options MAXUPRC=integer 1238Sets the soft 1239.Dv RLIMIT_NPROC 1240resource limit, which specifies the maximum number of simultaneous 1241processes a user is permitted to run, for process 0; 1242this value is inherited by its child processes. 1243It defaults to 1244.Em CHILD_MAX , 1245which is currently defined to be 160. 1246Setting 1247.Em MAXUPRC 1248to a value less than 1249.Em CHILD_MAX 1250is not permitted, as this would result in a violation of the semantics of 1251.St -p1003.1-90 . 1252.It Cd options NOFILE=integer 1253Sets the soft 1254.Dv RLIMIT_NOFILE 1255resource limit, which specifies the maximum number of open 1256file descriptors for each process; 1257this value is inherited by its child processes. 1258It defaults to 1259.Em OPEN_MAX , 1260which is currently defined to be 64. 1261.It Cd options DEFCORENAME=string 1262Sets the default value of the 1263.Em kern.defcorename 1264sysctl variable, otherwise it is set to 1265.Nm %n.core . 1266See 1267.Xr sysctl 8 1268and 1269.Xr sysctl 3 1270for details. 1271.It Cd options RASOPS_CLIPPING 1272Enables clipping within the 1273.Nm rasops 1274raster-console output system. 1275.Em NOTE : 1276only available on architectures that use 1277.Nm rasops 1278for console output. 1279.It Cd options RASOPS_SMALL 1280Removes optimized character writing code from the 1281.Nm rasops 1282raster-console output system. 1283.Em NOTE : 1284only available on architectures that use 1285.Nm rasops 1286for console output. 1287.It Cd options INCLUDE_CONFIG_FILE 1288Embeds the kernel config file used to define the kernel in the kernel 1289binary itself. 1290The embedded data also includes any files directly included by the config 1291file itself, e.g. 1292.Pa GENERIC.local 1293or 1294.Pa std.$MACHINE . 1295The embedded config file can be extracted from the resulting kernel by 1296the following command: 1297.Bd -literal -offset indent 1298strings netbsd | sed -n 's/^_CFG_//p' | unvis 1299.Ed 1300.It Cd options INCLUDE_JUST_CONFIG 1301Similar to the above option, but includes just the actual config file, 1302not any included files. 1303.It Cd options PIPE_SOCKETPAIR 1304Use slower, but smaller socketpair(2)-based pipe implementation instead 1305of default faster, but bigger one. 1306Primarily useful for installation kernels. 1307.It Cd options USERCONF 1308Compiles in the in-kernel device configuration manager. 1309See 1310.Xr userconf 4 1311for details. 1312.It Cd options PERFCTRS 1313Compiles in kernel support for CPU performance-monitoring counters. 1314See 1315.Xr pmc 1 1316for details. 1317.Em NOTE : 1318not available on all architectures. 1319.It Cd options XSERVER 1320Compiles in kernel support for 1321.Tn X11 1322on architectures that still use (or can use) the legacy 1323.Em pccons 1324console drivers rather than 1325.Xr wscons 4 . 1326These include bebox, i386, shark. 1327.It Cd options XSERVER_DDB 1328A supplement to XSERVER that adds support for entering 1329.Xr ddb 4 1330while in 1331.Tn X11 . 1332.El 1333.Ss Networking Options 1334.Bl -ohang 1335.It Cd options GATEWAY 1336Enables 1337.Em IPFORWARDING 1338(which see) 1339and (on most ports) increases the size of 1340.Em NMBCLUSTERS 1341(which see). 1342In general, 1343.Em GATEWAY 1344is used to indicate that a system should act as a router, and 1345.Em IPFORWARDING 1346is not invoked directly. 1347(Note that 1348.Em GATEWAY 1349has no impact on protocols other than 1350.Tn IP , 1351such as 1352.Tn CLNP 1353or 1354.Tn XNS ) . 1355.Em GATEWAY 1356option also compiles IPv4 fast forwarding code into the kernel. 1357.It Cd options IPFORWARDING=value 1358If 1359.Em value 1360is 1 this enables IP routing behavior. 1361If 1362.Em value 1363is 0 (the default), it disables it. 1364The 1365.Em GATEWAY 1366option sets this to 1 automatically. 1367With this option enabled, the machine will forward IP datagrams destined 1368for other machines between its interfaces. 1369Note that even without this option, the kernel will 1370still forward some packets (such as source routed packets) -- removing 1371.Em GATEWAY 1372and 1373.Em IPFORWARDING 1374is insufficient to stop all routing through a bastion host on a 1375firewall -- source routing is controlled independently. 1376To turn off source routing, use 1377.Em options IPFORWSRCRT=0 1378(which see). 1379Note that IP forwarding may be turned on and off independently of the 1380setting of the 1381.Em IPFORWARDING 1382option through the use of the 1383.Em net.inet.ip.forwarding 1384sysctl variable. 1385If 1386.Em net.inet.ip.forwarding 1387is 1, IP forwarding is on. 1388See 1389.Xr sysctl 8 1390and 1391.Xr sysctl 3 1392for details. 1393.It Cd options IPFORWSRCRT=value 1394If 1395.Em value 1396is set to zero, source routing of IP datagrams is turned off. 1397If 1398.Em value 1399is set to one (the default) or the option is absent, source routed IP 1400datagrams are forwarded by the machine. 1401Note that source routing of IP packets may be turned on and off 1402independently of the setting of the 1403.Em IPFORWSRCRT 1404option through the use of the 1405.Em net.inet.ip.forwsrcrt 1406sysctl variable. 1407If 1408.Em net.inet.ip.forwsrcrt 1409is 1, forwarding of source routed IP datagrams is on. 1410See 1411.Xr sysctl 8 1412and 1413.Xr sysctl 3 1414for details. 1415.It Cd options IFA_STATS 1416Tells the kernel to maintain per-address statistics on bytes sent 1417and received over (currently) internet and appletalk addresses. 1418.\"This can be a fairly expensive operation, so you probably want to 1419.\"keep this disabled. 1420The option is not recommended as it degrades system stability. 1421.It Cd options IFQ_MAXLEN=value 1422Increases the allowed size of the network interface packet queues. 1423The default queue size is 50 packets, and you do not normally need 1424to increase it. 1425.It Cd options MROUTING 1426Includes support for IP multicast routers. 1427You certainly want 1428.Em INET 1429with this. 1430Multicast routing is controlled by the 1431.Xr mrouted 8 1432daemon. 1433.It Cd options PIM 1434Includes support for Protocol Independent Multicast (PIM) routing. 1435You need 1436.Em MROUTING 1437and 1438.Em INET 1439with this. 1440.It Cd options INET 1441Includes support for the 1442.Tn TCP/IP 1443protocol stack. 1444You almost certainly want this. 1445See 1446.Xr inet 4 1447for details. 1448This option is currently required. 1449.It Cd options INET6 1450Includes support for the 1451.Tn IPv6 1452protocol stack. 1453See 1454.Xr inet6 4 1455for details. 1456Unlike 1457.Em INET , 1458.Em INET6 1459enables multicast routing code as well. 1460This option requires 1461.Em INET 1462at this moment, but it should not. 1463.It Cd options ND6_DEBUG 1464The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1465for debugging IPv6 neighbor discovery protocol handling. 1466See 1467.Xr sysctl 3 1468for details. 1469.It Cd options IPSEC 1470Includes support for the 1471.Tn IPsec 1472protocol. 1473See 1474.Xr ipsec 4 1475for details. 1476.It Cd options IPSEC_DEBUG 1477Enables debugging code in 1478.Tn IPsec 1479stack. 1480See 1481.Xr ipsec 4 1482for details. 1483.It Cd options IPSEC_ESP 1484Includes support for 1485.Tn IPsec 1486.Tn ESP 1487protocol. 1488See 1489.Xr ipsec 4 1490for details. 1491.It Cd options ALTQ 1492Enabled ALTQ (Alternate Queueing). 1493For simple rate-limiting, use 1494.Xr tbrconfig 8 1495to set up the interface transmission rate. 1496To use queueing disciplines, their appropriate kernel options should also 1497be defined (documented below). 1498Queueing disciplines are managed by 1499.Xr altqd 8 . 1500See 1501.Xr altq 9 1502for details. 1503.It Cd options ALTQ_HFSC 1504Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1505module. 1506HFSC supports both link-sharing and guaranteed real-time services. 1507HFSC employs a service curve based QoS model, and its unique feature 1508is an ability to decouple delay and bandwidth allocation. 1509Requires 1510.Em ALTQ_RED 1511to use the RED queueing discipline on HFSC classes, or 1512.Em ALTQ_RIO 1513to use the RIO queueing discipline on HFSC classes. 1514This option assumes 1515.Em ALTQ . 1516.It Cd options ALTQ_PRIQ 1517Include support for ALTQ-implemented PRIQ (Priority Queueing). 1518PRIQ implements a simple priority-based queueing discipline. 1519A higher priority class is always served first. 1520Requires 1521.Em ALTQ_RED 1522to use the RED queueing discipline on HFSC classes, or 1523.Em ALTQ_RIO 1524to use the RIO queueing discipline on HFSC classes. 1525This option assumes 1526.Em ALTQ . 1527.It Cd options ALTQ_WFQ 1528Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1529WFQ implements a weighted-round robin scheduler for a set of queues. 1530A weight can be assigned to each queue to give a different proportion 1531of the link capacity. 1532A hash function is used to map a flow to one of a set of queues. 1533This option assumes 1534.Em ALTQ . 1535.It Cd options ALTQ_FIFOQ 1536Include support for ALTQ-implemented FIFO queueing. 1537FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1538This option assumes 1539.Em ALTQ . 1540.It Cd options ALTQ_RIO 1541Include support for ALTQ-implemented RIO (RED with In/Out). 1542The original RIO has 2 sets of RED parameters; one for in-profile 1543packets and the other for out-of-profile packets. 1544At the ingress of the network, profile meters tag packets as IN or 1545OUT based on contracted profiles for customers. 1546Inside the network, IN packets receive preferential treatment by 1547the RIO dropper. 1548ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1549PHB of DiffServ (RFC 2597). 1550This option assumes 1551.Em ALTQ . 1552.It Cd options ALTQ_BLUE 1553Include support for ALTQ-implemented Blue buffer management. 1554Blue is another active buffer management mechanism. 1555This option assumes 1556.Em ALTQ . 1557.It Cd options ALTQ_FLOWVALVE 1558Include support for ALTQ-implemented Flowvalve. 1559Flowvalve is a simple implementation of a RED penalty box that identifies 1560and punishes misbehaving flows. 1561This option requires 1562.Em ALTQ_RED 1563and assumes 1564.Em ALTQ . 1565.It Cd options ALTQ_CDNR 1566Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1567packet marking/manipulation. 1568Traffic conditioners are components to meter, mark, or drop incoming 1569packets according to some rules. 1570As opposed to queueing disciplines, traffic conditioners handle incoming 1571packets at an input interface. 1572This option assumes 1573.Em ALTQ . 1574.It Cd options ALTQ_NOPCC 1575Disables use of processor cycle counter to measure time in ALTQ. 1576This option should be defined for a non-Pentium i386 CPU which does not 1577have TSC, SMP (per-CPU counters are not in sync), or power management 1578which affects processor cycle counter. 1579This option assumes 1580.Em ALTQ . 1581.It Cd options ALTQ_IPSEC 1582Include support for IPsec in IPv4 ALTQ. 1583This option assumes 1584.Em ALTQ . 1585.It Cd options ALTQ_JOBS 1586Undocumented at this time. 1587.It Cd options ALTQ_AFMAP 1588Include support for an undocumented ALTQ feature that is used to map an IP 1589flow to an ATM VC (Virtual Circuit). 1590This option assumes 1591.Em ALTQ . 1592.It Cd options ALTQ_LOCALQ 1593Include support for ALTQ-implemented local queues. 1594Its practical use is undefined. 1595Assumes 1596.Em ALTQ . 1597.It Cd options SUBNETSARELOCAL 1598Sets default value for net.inet.ip.subnetsarelocal variable, which 1599controls whether non-directly-connected subnets of connected networks 1600are considered "local" for purposes of choosing the MSS for a TCP 1601connection. 1602This is mostly present for historic reasons and completely irrelevant if 1603you enable Path MTU discovery. 1604.It Cd options HOSTZEROBROADCAST 1605Sets default value for net.inet.ip.hostzerobroadcast variable, which 1606controls whether the zeroth host address of each connected subnet is 1607also considered a broadcast address. 1608Default value is "1", for compatibility with old systems; if this is 1609set to zero on all hosts on a subnet, you should be able to fit an extra 1610host per subnet on the 1611".0" address. 1612.It Cd options MCLSHIFT=value 1613This option is the base-2 logarithm of the size of mbuf clusters. 1614The 1615.Bx 1616networking stack keeps network packets in a linked 1617list, or chain, of kernel buffer objects called mbufs. 1618The system provides larger mbuf clusters as an optimization for 1619large packets, instead of using long chains for large packets. 1620The mbuf cluster size, 1621or 1622.Em MCLBYTES , 1623must be a power of two, and is computed as two raised to the power 1624.Em MCLSHIFT . 1625On systems with Ethernet network adaptors, 1626.Em MCLSHIFT 1627is often set to 11, giving 2048-byte mbuf clusters, large enough to 1628hold a 1500-byte 1629.Tn Ethernet 1630frame in a single cluster. 1631Systems with network interfaces supporting larger frame sizes like 1632.Tn ATM , 1633.Tn FDDI , 1634or 1635.Tn HIPPI 1636may perform better with 1637.Em MCLSHIFT 1638set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1639respectively. 1640.It Cd options NS 1641Include support for the 1642.Tn Xerox 1643.Tn XNS 1644protocol stack. 1645See 1646.Xr ns 4 1647for details. 1648.It Cd options ISO,TPIP 1649Include support for the ubiquitous 1650.Tn OSI 1651protocol stack. 1652See 1653.Xr iso 4 1654for details. 1655This option assumes 1656.Em INET . 1657.It Cd options EON 1658Include support for tunneling 1659.Tn OSI 1660protocols over 1661.Tn IP . 1662Known to be broken, or at least very fragile, and undocumented. 1663.It Cd options CCITT,LLC,HDLC 1664Include support for the 1665.Tn CCITT 1666(nee 1667.Tn ITU-TSS ) 1668.Tn X.25 1669protocol stack. 1670The state of this code is currently unknown, and probably contains bugs. 1671This option assumes 1672.Em INET . 1673.It Cd options NETATALK 1674Include support for the 1675.Tn AppleTalk 1676protocol stack. 1677The kernel provides provision for the 1678.Em Datagram Delivery Protocol 1679(DDP), providing SOCK_DGRAM support and 1680.Tn AppleTalk 1681routing. 1682This stack is used by the 1683.Em NETATALK 1684package, which adds support for 1685.Tn AppleTalk 1686server services via user libraries and applications. 1687.It Cd options IPNOPRIVPORTS 1688Normally, only root can bind a socket descriptor to a so-called 1689.Dq privileged 1690.Tn TCP 1691port, that is, a port number in the range 0-1023. 1692This option eliminates those checks from the kernel. 1693This can be useful if there is a desire to allow daemons without 1694privileges to bind those ports, e.g., on firewalls. 1695The security tradeoffs in doing this are subtle. 1696This option should only be used by experts. 1697.It Cd options TCP_COMPAT_42 1698.Tn TCP 1699bug compatibility with 1700.Bx 4.2 . 1701In 1702.Bx 4.2 , 1703.Tn TCP 1704sequence numbers were 32-bit signed values. 1705Modern implementations of TCP use unsigned values. 1706This option clamps the initial sequence number to start in 1707the range 2^31 rather than the full unsigned range of 2^32. 1708Also, under 1709.Bx 4.2 , 1710keepalive packets must contain at least one byte or else 1711the remote end would not respond. 1712.It Cd options TCP_DEBUG 1713Record the last 1714.Em TCP_NDEBUG 1715TCP packets with SO_DEBUG set, and decode to the console if 1716.Em tcpconsdebug 1717is set. 1718.It Cd options TCP_NDEBUG 1719Number of packets to record for 1720.Em TCP_DEBUG . 1721Defaults to 100. 1722.It Cd options TCP_SENDSPACE=value 1723.It Cd options TCP_RECVSPACE=value 1724These options set the max TCP window size to other sizes than the default. 1725The TCP window sizes can be altered via 1726.Xr sysctl 8 1727as well. 1728.It Cd options TCP_INIT_WIN=value 1729This option sets the initial TCP window size for non-local connections, 1730which is used when the transmission starts. 1731The default size is 1, but if the machine should act more aggressively, 1732the initial size can be set to some other value. 1733The initial TCP window size can be set via 1734.Xr sysctl 8 1735as well. 1736.It Cd options PFIL_HOOKS 1737This option turns on the packet filter interface hooks. 1738See 1739.Xr pfil 9 1740for details. 1741This option assumes 1742.Em INET . 1743.It Cd options IPFILTER_LOG 1744This option, in conjunction with 1745.Em pseudo-device ipfilter , 1746enables logging of IP packets using ip-filter. 1747.It Cd options IPFILTER_DEFAULT_BLOCK 1748This option sets the default policy of ip-filter. 1749If it is set, ip-filter will block packets by default. 1750.It Cd options BRIDGE_IPF 1751This option causes 1752.Em bridge 1753devices to use the IP and/or IPv6 filtering hooks, forming 1754a link-layer filter that uses protocol-layer rules. 1755This option assumes the presence of 1756.Em pseudo-device ipfilter . 1757.It Cd options MBUFTRACE 1758This option can help track down mbuf leaks. 1759When enabled, mbufs are tagged with the devices and protocols using them, 1760which slightly decreases network performance. 1761This additional information can be viewed with 1762.Xr netstat 1 : 1763.Dl Ic netstat Fl mssv 1764Not all devices or protocols support this option. 1765.El 1766.Ss Sysctl Related Options 1767.Bl -ohang 1768.It Cd options SYSCTL_DISALLOW_CREATE 1769Disallows the creation or deletion of nodes from the sysctl tree, as 1770well as the assigning of descriptions to nodes that lack them, by any 1771process. 1772These operations are still available to kernel sub-systems, including 1773loadable kernel modules. 1774.It Cd options SYSCTL_DISALLOW_KWRITE 1775Prevents processes from adding nodes to the sysctl tree that make 1776existing kernel memory areas writeable. 1777Sections of kernel memory can still be read and new nodes that own 1778their own data may still be writeable. 1779.It Cd options SYSCTL_DEBUG_SETUP 1780Causes the SYSCTL_SETUP routines to print a brief message when they 1781are invoked. 1782This is merely meant as an aid in determining the order in which 1783sections of the tree are created. 1784.It Cd options SYSCTL_DEBUG_CREATE 1785Prints a message each time 1786.Fn sysctl_create , 1787the function that adds nodes to the tree, is called. 1788.It Cd options SYSCTL_INCLUDE_DESCR 1789Causes the kernel to include short, human readable descriptions for 1790nodes in the sysctl tree. 1791The descriptions can be retrieved programmatically (see 1792.Xr sysctl 3 ) , 1793or by the sysctl binary itself (see 1794.Xr sysctl 8 ) . 1795The descriptions are meant to give an indication of the purpose and/or 1796effects of a given node's value, not replace the documentation for the 1797given subsystem as a whole. 1798.El 1799.Ss System V IPC Options 1800.Bl -ohang 1801.It Cd options SYSVMSG 1802Includes support for 1803.At V 1804style message queues. 1805See 1806.Xr msgctl 2 , 1807.Xr msgget 2 , 1808.Xr msgrcv 2 , 1809.Xr msgsnd 2 . 1810.It Cd options SYSVSEM 1811Includes support for 1812.At V 1813style semaphores. 1814See 1815.Xr semctl 2 , 1816.Xr semget 2 , 1817.Xr semop 2 . 1818.It Cd options SEMMNI=value 1819Sets the number of 1820.At V 1821style semaphore identifiers. 1822The GENERIC config file for your port will have the default. 1823.It Cd options SEMMNS=value 1824Sets the number of 1825.At V 1826style semaphores in the system. 1827The GENERIC config file for your port will have the default. 1828.It Cd options SEMUME=value 1829Sets the maximum number of undo entries per process for 1830.At V 1831style semaphores. 1832The GENERIC config file for your port will have the default. 1833.It Cd options SEMMNU=value 1834Sets the number of undo structures in the system for 1835.At V 1836style semaphores. 1837The GENERIC config file for your port will have the default. 1838.It Cd options SYSVSHM 1839Includes support for 1840.At V 1841style shared memory. 1842See 1843.Xr shmat 2 , 1844.Xr shmctl 2 , 1845.Xr shmdt 2 , 1846.Xr shmget 2 . 1847.It Cd options SHMMAXPGS=value 1848Sets the maximum number of 1849.At V 1850style shared memory pages that are available through the 1851.Xr shmget 2 1852system call. 1853Default value is 1024 on most ports. 1854See 1855.Pa /usr/include/machine/vmparam.h 1856for the default. 1857.El 1858.Ss VM Related Options 1859.Bl -ohang 1860.It Cd options NMBCLUSTERS=value 1861The number of mbuf clusters the kernel supports. 1862Mbuf clusters are MCLBYTES in size (usually 2k). 1863This is used to compute the size of the kernel VM map 1864.Em mb_map , 1865which maps mbuf clusters. 1866Default on most ports is 1024 (2048 with 1867.Dq options GATEWAY 1868). 1869See 1870.Pa /usr/include/machine/param.h 1871for exact default information. 1872Increase this value if you get 1873.Dq mclpool limit reached 1874messages. 1875.It Cd options NKMEMPAGES=value 1876.It Cd options NKMEMPAGES_MIN=value 1877.It Cd options NKMEMPAGES_MAX=value 1878Size of kernel VM map 1879.Em kmem_map , 1880in PAGE_SIZE-sized chunks (the VM page size; this value may be read 1881from the 1882.Xr sysctl 8 1883variable 1884.Em hw.pagesize 1885). 1886This VM map is used to map the kernel malloc arena. 1887The kernel attempts to auto-size this map based on the amount of 1888physical memory in the system. 1889Platform-specific code may place bounds on this computed size, 1890which may be viewed with the 1891.Xr sysctl 8 1892variable 1893.Em vm.nkmempages . 1894See 1895.Pa /usr/include/machine/param.h 1896for the default upper and lower bounds. 1897The related options 1898.Sq NKMEMPAGES_MIN 1899and 1900.Sq NKMEMPAGES_MAX 1901allow the bounds to be overridden in the kernel configuration file. 1902These options are provided in the event the computed value is 1903insufficient resulting in an 1904.Dq out of space in kmem_map 1905panic. 1906.It Cd options SB_MAX=value 1907Sets the max size in bytes that a socket buffer is allowed to occupy. 1908The default is 256k, but sometimes it needs to be increased, for example 1909when using large TCP windows. 1910This option can be changed via 1911.Xr sysctl 8 1912as well. 1913.It Cd options SOMAXKVA=value 1914Sets the maximum size of kernel virtual memory that the socket buffers 1915are allowed to use. 1916The default is 16MB, but in situations where for example large TCP 1917windows are used this value must also be increased. 1918This option can be changed via 1919.Xr sysctl 8 1920as well. 1921.It Cd options BUFCACHE=value 1922Size of the buffer cache as a percentage of total available 1923.Tn RAM . 1924Ignored if BUFPAGES is also specified. 1925.It Cd options NBUF=value 1926Sets the number of buffer headers available, i.e., the number of 1927open files that may have a buffer cache entry. 1928Each buffer header 1929requires MAXBSIZE (machine dependent, but usually 65536) bytes. 1930The default value is machine dependent, but is usually equal to the 1931value of BUFPAGES. 1932If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 1933then NBUF may be reduced at run time so that the storage allocated 1934for buffer headers doesn't exceed that limit. 1935.It Cd options BUFPAGES=value 1936These options set the number of pages available for the buffer cache. 1937Their default value is a machine dependent value, often calculated as 1938between 5% and 10% of total available 1939.Tn RAM . 1940.It Cd options MAXTSIZ=bytes 1941Sets the maximum size limit of a process' text segment. 1942See 1943.Pa /usr/include/machine/vmparam.h 1944for the port-specific default. 1945.It Cd options DFLDSIZ=bytes 1946Sets the default size limit of a process' data segment, the value that 1947will be returned as the soft limit for 1948.Dv RLIMIT_DATA 1949(as returned by 1950.Xr getrlimit 2 ) . 1951See 1952.Pa /usr/include/machine/vmparam.h 1953for the port-specific default. 1954.It Cd options MAXDSIZ=bytes 1955Sets the maximum size limit of a process' data segment, the value that 1956will be returned as the hard limit for 1957.Dv RLIMIT_DATA 1958(as returned by 1959.Xr getrlimit 2 ) . 1960See 1961.Pa /usr/include/machine/vmparam.h 1962for the port-specific default. 1963.It Cd options DFLSSIZ=bytes 1964Sets the default size limit of a process' stack segment, the value that 1965will be returned as the soft limit for 1966.Dv RLIMIT_STACK 1967(as returned by 1968.Xr getrlimit 2 ) . 1969See 1970.Pa /usr/include/machine/vmparam.h 1971for the port-specific default. 1972.It Cd options MAXSSIZ=bytes 1973Sets the maximum size limit of a process' stack segment, the value that 1974will be returned as the hard limit for 1975.Dv RLIMIT_STACK 1976(as returned by 1977.Xr getrlimit 2 ) . 1978See 1979.Pa /usr/include/machine/vmparam.h 1980for the port-specific default. 1981.It Cd options DUMP_ON_PANIC=integer 1982Defaults to one. 1983If set to zero, the kernel will not dump to the dump device when 1984it panics, though dumps can still be forced via 1985.Xr ddb 4 1986with the 1987.Dq sync 1988command. 1989Note that this sets the value of the 1990.Em kern.dump_on_panic 1991.Xr sysctl 3 1992variable which may be changed at run time -- see 1993.Xr sysctl 8 1994for details. 1995.It Cd options USE_TOPDOWN_VM 1996User space memory allocations (as made by 1997.Xr mmap 2 ) 1998will be arranged in a 1999.Dq top down 2000fashion instead of the traditional 2001.Dq upwards from MAXDSIZ \+ vm_daddr 2002method. 2003This includes the placement of 2004.Xr ld.so 1 . 2005Arranging memory in this manner allows either (or both of) the heap or 2006.Xr mmap 2 2007allocated space to grow larger than traditionally possible. 2008This option is not available on all ports, but is instead expected to be 2009offered on a port-by-port basis, after which some ports will commit to 2010using it by default. 2011See the files 2012.Pa /usr/include/uvm/uvm_param.h 2013for some implementation details, and 2014.Pa /usr/include/machine/vmparam.h 2015for port specific details including availability. 2016.El 2017.Ss amiga-specific Options 2018.Bl -ohang 2019.It Cd options BB060STUPIDROM 2020When the bootloader (which passes 2021.Tn AmigaOS 2022.Tn ROM 2023information) claims we have a 68060 2024.Tn CPU 2025without 2026.Tn FPU , 2027go look into the Processor Configuration Register (PCR) to find out. 2028You need this with 2029.Tn Amiga 2030.Tn ROM Ns s 2031up to (at least) V40.xxx (OS3.1), 2032when you boot via the bootblocks and don't have a DraCo. 2033.It Cd options IOBZCLOCK=frequency 2034The IOBlix boards come with two different serial master clocks: older ones 2035use 24 MHz, newer ones use 22.1184 MHz. 2036The driver normally assumes the latter. 2037If your board uses 24 MHz, you can recompile your kernel with 2038options IOBZCLOCK=24000000 2039or patch the kernel variable 2040.Tn iobzclock 2041to the same value. 2042.It Cd options LIMITMEM=value 2043If there, limit the part of the first memory bank used by 2044.Nx 2045to value megabytes. 2046Default is unlimited. 2047.It Cd options NKPTADD=addvalue 2048.It Cd options NKPTADDSHIFT=shiftvalue 2049The 2050.Tn CPU 2051specific 2052.Tn MMU 2053table for the kernel is pre-allocated at kernel startup time. 2054Part of it is scaled with 2055.Va maxproc , 2056to have enough room to hold the user program 2057.Tn MMU 2058tables; the second part is a fixed amount for the kernel itself. 2059.Pp 2060The third part accounts for the size of the file buffer cache. 2061Its size is either 2062.Dv NKPTADD 2063pages (if defined) or memory size in bytes divided by two to 2064the power of 2065.Dv NKPTADDSHIFT . 2066The default is undefined 2067.Dv NKPTADD 2068and 2069.Dv NKPTADDSHIFT=24 , 2070allowing for 16 buffers per megabyte of main memory (while 2071a GENERIC kernel allocates about half of that). 2072When you get "can't get KPT page" panics, you should increase 2073.Dv NKPTADD 2074(if defined), or decrease 2075.Dv NKPTADDSHIFT 2076by one. 2077.It Cd options P5PPC68KBOARD 2078Add special support for Phase5 mixed 68k+PPC boards. 2079Currently, this only affects rebooting from 2080.Nx 2081and is only needed on 68040+PPC, not on 208268060+PPC; without this, affected machines will hang after 2083.Nx 2084has shut 2085down and will only restart after a keyboard reset or a power cycle. 2086.El 2087.Ss arm32-specific Options 2088.Bl -ohang 2089.It Cd options FRENCH_KBD 2090Include translation for French keyboards when using 2091.Em pccons 2092on a Shark. 2093.It Cd options FINNISH_KBD 2094Include translation for Finnish keyboards when using 2095.Em pccons 2096on a Shark. 2097.It Cd options GERMAN_KBD 2098Include translation for German keyboards when using 2099.Em pccons 2100on a Shark. 2101.It Cd options NORWEGIAN_KBD 2102Include translation for French keyboards when using 2103.Em pccons 2104on a Shark. 2105.El 2106.Ss atari-specific Options 2107.Bl -ohang 2108.It Cd options DISKLABEL_AHDI 2109Include support for AHDI (native Atari) disklabels. 2110.It Cd options DISKLABEL_NBDA 2111Include support for 2112.Nx Ns Tn /atari 2113labels. 2114If you don't set this option, it will be set automatically. 2115.Nx Ns Tn /atari 2116will not work without it. 2117.It Cd options FALCON_SCSI 2118Include support for the 5380-SCSI configuration as found on the Falcon. 2119.It Cd options RELOC_KERNEL 2120If set, the kernel will relocate itself to TT-RAM, if possible. 2121This will give you a slightly faster system. 2122.Em Beware 2123that on some TT030 systems, 2124the system will frequently dump with MMU-faults with this option enabled. 2125.It Cd options SERCONSOLE 2126Allow the modem1-port to act as the system-console. 2127A carrier should be active on modem1 during system boot to active 2128the console functionality. 2129.It Cd options TT_SCSI 2130Include support for the 5380-SCSI configuration as found on the TT030 2131and Hades. 2132.El 2133.Ss i386-specific Options 2134.Bl -ohang 2135.It Cd options I386_CPU,I486_CPU,I586_CPU,I686_CPU 2136Include support for a particular class of 2137.Tn CPU 2138.Po 2139.Tn i386 , 2140.Tn i486 , 2141.Tn Pentium , 2142or 2143.Tn Pentium Pro 2144.Pc . 2145If the appropriate class for your 2146.Tn CPU 2147is not configured, the kernel will use the highest class available 2148that will work. 2149In general, using the correct 2150.Tn CPU 2151class will result in the best performance. 2152At least one of these options must be present. 2153.It Cd options ENHANCED_SPEEDSTEP 2154Include support for the 2155.Tn Enhanced SpeedStep Technology 2156present in newer 2157.Tn CPU Ns s . 2158.It Cd options EST_FREQ_USERWRITE 2159Allow any user to change the frequency of an 2160.Tn Enhanced SpeedStep Technology 2161capable 2162.Tn CPU . 2163.It Cd options CPURESET_DELAY=value 2164Specifies the time (in millisecond) to wait before doing a hardware reset 2165in the last phase of a reboot. 2166This gives the user a chance to see error messages from the shutdown 2167operations (like NFS unmounts, buffer cache flush, etc ...). 2168Setting this to 0 will disable the delay. 2169Default is 2 seconds. 2170.It Cd options MATH_EMULATE 2171Include the floating point emulator. 2172This is useful only for 2173.Tn CPU Ns s 2174that lack an 2175internal Floating Point Unit 2176.Pq Tn FPU 2177or co-processor. 2178.It Cd options VM86 2179Include support for virtual 8086 mode, used by 2180.Tn DOS 2181emulators and X servers to run BIOS code, e.g., for some VESA routines. 2182.It Cd options USER_LDT 2183Include i386-specific system calls for modifying the local descriptor table, 2184used by Windows emulators. 2185.It Cd options REALBASEMEM=integer 2186Overrides the base memory size passed in from the boot block. 2187(Value given in kilobytes.) 2188Use this option only if the boot block reports the size incorrectly. 2189(Note that some 2190.Tn BIOS Ns es 2191put the extended 2192.Tn BIOS 2193data area at the top of base memory, and therefore report a smaller 2194base memory size to prevent programs overwriting it. 2195This is correct behavior, and you should not use the 2196.Em REALBASEMEM 2197option to access this memory). 2198.It Cd options REALEXTMEM=integer 2199Overrides the extended memory size passed in from the boot block. 2200(Value given in kilobytes. 2201Extended memory does not include the first megabyte.) 2202Use this option only if the boot block reports the size incorrectly. 2203.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2204Select a non-US keyboard layout for the 2205.Em pccons 2206console driver. 2207.It Cd options CYRIX_CACHE_WORKS 2208Relevant only to the Cyrix 486DLC CPU. 2209This option is used to turn on the cache in hold-flush mode. 2210It is not turned on by default because it is known to have problems in 2211certain motherboard implementations. 2212.It Cd options CYRIX_CACHE_REALLY_WORKS 2213Relevant only to the Cyrix 486DLC CPU. 2214This option is used to turn on the cache in write-back mode. 2215It is not turned on by default because it is known to have problems in 2216certain motherboard implementations. 2217In order for this option to take effect, option 2218.Em CYRIX_CACHE_WORKS 2219must also be specified. 2220.It Cd options PCIBIOS 2221Enable support for initializing the 2222.Tn PCI 2223bus using information from the 2224.Tn BIOS . 2225See 2226.Xr pcibios 4 2227for details. 2228.It Cd options KSTACK_CHECK_DR0 2229Detect kernel stack overflow using DR0 register. 2230This option uses DR0 register exclusively so you can't use DR0 register for 2231other purpose (e.g., hardware breakpoint) if you turn this on. 2232.It Cd options MTRR 2233Include support for accessing MTRR registers from user-space. 2234See 2235.Xr i386_get_mtrr 2 . 2236.It Cd options BEEP_ONHALT 2237Make the system speaker emit several beeps when it is completely safe to 2238power down the computer after a 2239.Xr halt 8 2240command. 2241Requires 2242.Xr sysbeep 4 2243support. 2244.It Cd options BEEP_ONHALT_COUNT=times 2245Number of times to beep the speaker when 2246.Cd options BEEP_ONHALT 2247is enabled. 2248Defaults to 3. 2249.It Cd options BEEP_ONHALT_PITCH=hz 2250The tone frequency used when 2251.Cd options BEEP_ONHALT 2252option, in hertz. 2253Defaults to 1500. 2254.It Cd options BEEP_ONHALT_PERIOD=msecs 2255The duration of each beep when 2256.Cd options BEEP_ONHALT 2257is enabled, in milliseconds. 2258Defaults to 250. 2259.El 2260.Ss isa-specific Options 2261Options specific to 2262.Xr isa 4 2263busses. 2264.Bl -ohang 2265.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2266Control the section of IO bus space used for PCMCIA bus space mapping. 2267Ideally the probed defaults are satisfactory, however in practice 2268that is not always the case. 2269See 2270.Xr pcmcia 4 2271for details. 2272.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2273Controls the allowable interrupts that may be used for 2274.Tn PCMCIA 2275devices. 2276This mask is a logical-or of power-of-2s of allowable interrupts: 2277.Bd -literal -offset 04n 2278.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2279 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2280 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2281 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2282 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2283.Ed 2284.El 2285.Ss m68k-specific Options 2286.Bl -ohang 2287.It Cd options FPU_EMULATE 2288Include support for MC68881/MC68882 emulator. 2289.It Cd options FPSP 2290Include support for 68040 floating point. 2291.It Cd options M68020,M68030,M68040,M68060 2292Include support for a specific 2293.Tn CPU , 2294at least one (the one you are using) should be specified. 2295.It Cd options M060SP 2296Include software support for 68060. 2297This provides emulation of unimplemented 2298integer instructions as well as emulation of unimplemented floating point 2299instructions and data types and software support for floating point traps. 2300.El 2301.Ss powerpc-specific Options 2302.Bl -ohang 2303.It Cd options PMAP_MEMLIMIT=value 2304Limit the amount of memory seen by the kernel to 2305.Ar value 2306bytes (OEA only). 2307.El 2308.Ss sparc-specific Options 2309.Bl -ohang 2310.It Cd options AUDIO_DEBUG 2311Enable simple event debugging of the logging of the 2312.Xr audio 4 2313device. 2314.It Cd options BLINK 2315Enable blinking of LED. 2316Blink rate is full cycle every N seconds for 2317N \*[Lt] then current load average. 2318See 2319.Xr getloadavg 3 . 2320.\" .It Cd options COLORFONT_CACHE 2321.\" What does this do? 2322.It Cd options COUNT_SW_LEFTOVERS 2323Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2324sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2325variables accessible from 2326.Xr ddb 4 . 2327See 2328.Xr sw 4 . 2329.It Cd options DEBUG_ALIGN 2330Adds debugging messages calls when user-requested alignment fault 2331handling happens. 2332.It Cd options DEBUG_EMUL 2333Adds debugging messages calls for emulated floating point and 2334alignment fixing operations. 2335.It Cd options DEBUG_SVR4 2336Prints registers messages calls for emulated SVR4 getcontext and 2337setcontext operations. 2338See 2339.Em options COMPAT_SVR4 . 2340.It Cd options EXTREME_DEBUG 2341Adds debugging functions callable from 2342.Xr ddb 4 . 2343The debug_pagetables, test_region and print_fe_map 2344functions print information about page tables for the SUN4M 2345platforms only. 2346.It Cd options EXTREME_EXTREME_DEBUG 2347Adds extra info to 2348.Em options EXTREME_DEBUG . 2349.It Cd options FPU_CONTEXT 2350Make 2351.Em options COMPAT_SVR4 2352getcontext and setcontext include floating point registers. 2353.It Cd options MAGMA_DEBUG 2354Adds debugging messages to the 2355.Xr magma 4 2356device. 2357.It Cd options RASTERCONS_FULLSCREEN 2358Use the entire screen for the console. 2359.It Cd options RASTERCONS_SMALLFONT 2360Use the Fixed font on the console, instead of the normal font. 2361.It Cd options SUN4 2362Support sun4 class machines. 2363.It Cd options SUN4C 2364Support sun4c class machines. 2365.It Cd options SUN4M 2366Support sun4m class machines. 2367.It Cd options SUN4_MMU3L 2368.\" XXX ??? 2369Enable support for sun4 3-level MMU machines. 2370.It Cd options V9 2371Enable SPARC V9 assembler in 2372.Xr ddb 4 . 2373.El 2374.Ss sparc64-specific Options 2375.Bl -ohang 2376.It Cd options AUDIO_DEBUG 2377Enable simple event debugging of the logging of the 2378.Xr audio 4 2379device. 2380.It Cd options BLINK 2381Enable blinking of LED. 2382Blink rate is full cycle every N seconds for 2383N \*[Lt] then current load average. 2384See 2385.Xr getloadavg 3 . 2386.El 2387.Ss x68k-specific Options 2388.Bl -ohang 2389.It Cd options EXTENDED_MEMORY 2390Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2391.It Cd options JUPITER 2392Include support for Jupiter-X MPU accelerator 2393.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2394Use the built-in serial port as the system-console. 2395Speed is specified in bps, defaults to 9600. 2396.It Cd options ITE_KERNEL_ATTR=value 2397Set the kernel message attribute for ITE. 2398Value, an integer, is a logical or of the following values: 2399.Bl -tag -width 4n -compact -offset indent 2400.It 1 2401color inversed 2402.It 2 2403underlined 2404.It 4 2405bolded 2406.El 2407.El 2408.\" The following requests should be uncommented and used where appropriate. 2409.\" .Sh FILES 2410.\" .Sh EXAMPLES 2411.Sh SEE ALSO 2412.Xr gdb 1 , 2413.Xr ktrace 1 , 2414.Xr pmc 1 , 2415.Xr quota 1 , 2416.Xr gettimeofday 2 , 2417.Xr i386_get_mtrr 2 , 2418.Xr i386_iopl 2 , 2419.Xr msgctl 2 , 2420.Xr msgget 2 , 2421.Xr msgrcv 2 , 2422.Xr msgsnd 2 , 2423.Xr ntp_adjtime 2 , 2424.Xr ntp_gettime 2 , 2425.Xr semctl 2 , 2426.Xr semget 2 , 2427.Xr semop 2 , 2428.Xr shmat 2 , 2429.Xr shmctl 2 , 2430.Xr shmdt 2 , 2431.Xr shmget 2 , 2432.Xr sysctl 3 , 2433.Xr apm 4 , 2434.Xr ddb 4 , 2435.Xr inet 4 , 2436.Xr iso 4 , 2437.Xr lkm 4 , 2438.Xr md 4 , 2439.Xr ns 4 , 2440.Xr pcibios 4 , 2441.Xr pcmcia 4 , 2442.Xr ppp 4 , 2443.Xr userconf 4 , 2444.Xr wscons 4 , 2445.Xr config 8 , 2446.Xr edquota 8 , 2447.Xr init 8 , 2448.Xr mdsetimage 8 , 2449.Xr mount_cd9660 8 , 2450.Xr mount_fdesc 8 , 2451.Xr mount_kernfs 8 , 2452.Xr mount_lfs 8 , 2453.Xr mount_mfs 8 , 2454.Xr mount_msdos 8 , 2455.Xr mount_nfs 8 , 2456.Xr mount_ntfs 8 , 2457.Xr mount_null 8 , 2458.Xr mount_portal 8 , 2459.Xr mount_procfs 8 , 2460.Xr mount_umap 8 , 2461.Xr mount_union 8 , 2462.Xr mrouted 8 , 2463.Xr newfs_lfs 8 , 2464.Xr ntpd 8 , 2465.Xr quotaon 8 , 2466.Xr rpc.rquotad 8 , 2467.Xr sysctl 8 2468.Sh HISTORY 2469The 2470.Nm 2471man page first appeared in 2472.Nx 1.3 . 2473.Sh BUGS 2474The 2475.Em INET 2476option should not be required. 2477The 2478.Em EON 2479option should be a pseudo-device, and is also very fragile. 2480