1.\" $NetBSD: options.4,v 1.409 2011/10/02 16:39:46 jmcneill 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 October 2, 2011 34.Dt OPTIONS 4 35.Os 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Qq Ar filename 66Conditionally includes another kernel configuration file whose name is 67.Ar filename , 68which may be double-quoted and may be an explicit path or relative to 69the kernel source directory. 70Failure to open the named file is ignored. 71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ 72Oo dumps on Ar dumpdev Oc 73Defines a configuration whose kernel executable is named 74.Ar exec_name , 75normally 76.Dq netbsd , 77with its root file system of type 78.Ar fstype 79on the device 80.Ar rootdev , 81and optionally specifying the location of kernel core dumps on the device 82.Ar dumpdev . 83.Ar dev 84or 85.Ar dumpdev 86and 87.Ar fstype 88may be specified as 89.Dq \&? , 90which is a wild card. 91The root 92.Ar fstype 93and 94.Ar dumpdev 95are optional and assumed to be wild carded if they are not specified. 96.It Ar device_instance No at Ar attachment \ 97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc 98Define an instance of the device driver 99.Ar device_instance 100that attaches to the bus or device named 101.Ar attachment . 102An 103.Ar attachment 104may require additional information on where the device can be found, such 105as an address, channel, function, offset, and/or slot, referred to as 106.Ar locators , 107whose 108.Ar value 109often may be a wild card, 110.Dq \&? . 111Some device drivers have one or more 112.Ar flags 113that can be adjusted to affect the way they operate. 114.It Sy file-system Ar fs_name Op , Ar fs_name Op ... 115Include support for the file-system 116.Ar fs_name . 117.It Sy ident Qq Ar string 118Sets the kernel identification string to 119.Ar string . 120.It Sy include Qq Ar filename 121Functions the same as 122.Ar cinclude , 123except failure to open 124.Ar filename 125produces a fatal error. 126.It Sy options Ar option_name Op , Ar option_name=value Op ... 127Specifies (or sets) the option, or comma-separated list of options, 128.Ar option_name . 129Some options expect to be assigned a value, which may be an integer, 130a double-quoted word, a bare word, or an empty string 131.Pq Qq . 132Note that those are eventually handled by the C compiler, so the rules 133of that language apply. 134.Pp 135.Em Note : 136Options that are not defined by device definition files are passed to 137the compile process as 138.Fl D 139flags to the C compiler. 140.It Sy makeoptions Ar name=value 141Defines a 142.Xr make 1 143macro 144.Ar name 145with the value 146.Ar value 147in the kernel Makefile. 148.It Sy maxusers Ar integer 149Set the maxusers variable in the kernel. 150.It Sy no Ar keyword Ar name Op Ar arguments Op ... 151For the 152.Xr config 1 153.Ar keywords 154file-system, makeoptions, options, and pseudo-device, 155.Ar no 156removes the file-system, makeoption, options, or pseudo-device, 157.Ar name . 158This is useful when a kernel configuration file includes another which 159has undesired options. 160.Pp 161For example, a local configuration file that wanted the kitchen sink, but 162not COMPAT_09 or bridging, might be: 163.Bd -literal -offset indent 164include "arch/i386/conf/GENERIC" 165no options COMPAT_09 166no pseudo-device bridge 167.Ed 168.It Sy pseudo-device Ar name Op Ar N 169Includes support for the pseudo-device 170.Ar name . 171Some pseudo-devices can have multiple or 172.Ar N 173instances. 174.El 175.Ss Compatibility Options 176.Bl -ohang 177.It Cd options COMPAT_09 178Enable binary compatibility with 179.Nx 0.9 . 180This enables support for 18116-bit user, group, and process IDs (following revisions support 18232-bit identifiers). 183It also allows the use of the deprecated 184.Xr getdomainname 3 , 185.Xr setdomainname 3 , 186and 187.Xr uname 3 188syscalls. 189This option also allows using numeric file system identifiers rather 190than strings. 191Post 192.Nx 0.9 193versions use string identifiers. 194.It Cd options COMPAT_10 195Enable binary compatibility with 196.Nx 1.0 . 197This option allows the use of the file system name of 198.Dq ufs 199as an alias for 200.Dq ffs . 201The name 202.Dq ffs 203should be used post 1.0 in 204.Pa /etc/fstab 205and other files. 206It also adds old syscalls for the 207.At V 208shared memory interface. 209This was changed post 1.0 to work on 64-bit architectures. 210This option also enables 211.Dq sgtty 212compatibility, without which programs using the old interface produce 213an 214.Dq inappropriate ioctl 215error, and 216.Pa /dev/io 217only works when this option is set in the kernel, 218see 219.Xr io 4 220on ports that support it. 221.It Cd options COMPAT_11 222Enable binary compatibility with 223.Nx 1.1 . 224This allows binaries running on the i386 port to gain direct access to 225the io ports by opening 226.Pa /dev/io 227read/write. 228This functionality was replaced by 229.Xr i386_iopl 2 230post 1.1. 231On the 232.Tn Atari 233port, the location of the disk label was moved after 1.1. 234When the 235.Em COMPAT_11 236option is set, the kernel will read (pre) 1.1 style disk labels as a 237last resort. 238When a disk label is re-written, the old style label will be replaced 239with a post 1.1 style label. 240This also enables the 241.Em EXEC_ELF_NOTELESS 242option. 243.It Cd options COMPAT_12 244Enable binary compatibility with 245.Nx 1.2 . 246This allows the use of old syscalls for 247.Fn reboot 248and 249.Fn swapon . 250The syscall numbers were changed post 1.2 to add functionality to the 251.Xr reboot 2 252syscall, and the new 253.Xr swapctl 2 254interface was introduced. 255This also enables the 256.Em EXEC_ELF_NOTELESS 257option. 258.It Cd options COMPAT_13 259Enable binary compatibility with 260.Nx 1.3 . 261This allows the use of old syscalls for 262.Fn sigaltstack , 263and also enables the old 264.Xr swapctl 2 265command 266.Dv SWAP_STATS 267(now called 268.Dv SWAP_OSTATS ) , 269which does not include the 270.Fa se_path 271member of 272.Va struct swapent . 273.It Cd options COMPAT_14 274Enable binary compatibility with 275.Nx 1.4 . 276This allows some old 277.Xr ioctl 2 278on 279.Xr wscons 4 280to be performed, and allows the 281.Dv NFSSVC_BIOD 282mode of the 283.Xr nfssvc 2 284system call to be used for compatibility with the deprecated nfsiod program. 285.It Cd options COMPAT_15 286Enable binary compatibility with 287.Nx 1.5 . 288Since there were no API changes from 289.Nx 1.5 290and 291.Nx 1.6 , 292this option does nothing. 293.It Cd options COMPAT_16 294Enable binary compatibility with 295.Nx 1.6 . 296This allows the use of old signal trampoline code which has been deprecated 297with the addition of 298.Xr siginfo 2 . 299.It Cd options COMPAT_20 300Enable binary compatibility with 301.Nx 2.0 . 302This allows the use of old syscalls for 303.Fn statfs , 304.Fn fstatfs , 305.Fn getfsstat 306and 307.Fn fhstatfs , 308which have been deprecated with the addition of the 309.Xr statvfs 2 , 310.Xr fstatvfs 2 , 311.Xr getvfsstat 2 312and 313.Xr fhstatvfs 2 314system calls. 315.It Cd options COMPAT_30 316Enable binary compatibility with 317.Nx 3.0 . 318See 319.Xr compat_30 8 320for details about the changes made after the 321.Nx 3.0 322release. 323.It Cd options COMPAT_43 324Enables compatibility with 325.Bx 4.3 . 326This adds an old syscall for 327.Xr lseek 2 . 328It also adds the ioctls for 329.Dv TIOCGETP 330and 331.Dv TIOCSETP . 332The return values for 333.Xr getpid 2 , 334.Xr getgid 2 , 335and 336.Xr getuid 2 337syscalls are modified as well, to return the parent's PID and 338UID as well as the current process's. 339It also enables the deprecated 340.Dv NTTYDISC 341terminal line discipline. 342It also provides backwards compatibility with 343.Dq old 344SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 345binary compatibility with code written before the introduction of the 346sa_len field in sockaddrs. 347It also enables 348support for some older pre 349.Bx 4.4 350socket calls. 351.It Cd options COMPAT_BSDPTY 352This option is currently on by default and enables the pty multiplexer 353.Xr ptm 4 354and 355.Xr ptmx 4 356to find and use ptys named 357.Pa /dev/ptyXX 358(master) and 359.Pa /dev/ttyXX 360(slave). 361Eventually this option will become optional as ptyfs based pseudo-ttys become 362the default, see 363.Xr mount_ptyfs 8 . 364.It Cd options COMPAT_SVR4 365On those architectures that support it, this enables binary 366compatibility with 367.At V.4 368applications built for the same architecture. 369This currently includes the i386, m68k, and sparc ports. 370.It Cd options COMPAT_LINUX 371On those architectures that support it, this enables binary 372compatibility with Linux ELF and 373.Xr a.out 5 374applications built for the same architecture. 375This currently includes the alpha, arm, i386, m68k, mips, powerpc and 376x86_64 ports. 377.It Cd options COMPAT_LINUX32 378On those 64 bit architectures that support it, this enables binary 379compatibility with 32 bit Linux binaries. 380For now this is limited to running i386 ELF Linux binaries on amd64. 381.It Cd options COMPAT_SUNOS 382On those architectures that support it, this enables binary 383compatibility with 384.Tn SunOS 4.1 385applications built for the same architecture. 386This currently includes the sparc, sparc64 and most or all m68k ports. 387Note that the sparc64 requires the 388.Em COMPAT_NETBSD32 389option for 64-bit kernels, in addition to this option. 390.It Cd options COMPAT_ULTRIX 391On those architectures that support it, this enables binary 392compatibility with 393.Tn ULTRIX 394applications built for the same architecture. 395This currently is limited to the pmax. 396The functionality of this option is unknown. 397.It Cd options COMPAT_FREEBSD 398On those architectures that support it, this enables binary 399compatibility with 400.Fx 401applications built for the same architecture. 402At the moment this is limited to the i386 port. 403.It Cd options COMPAT_IBCS2 404On those architectures that support it, this enables binary 405compatibility with iBCS2 or SVR3 applications built for the same architecture. 406This is currently limited to the i386 and vax ports. 407.It Cd options COMPAT_OSF1 408On those architectures that support it, this enables binary 409compatibility with 410.Tn Digital 411.Ux 412.Po 413formerly 414.Tn OSF/1 415.Pc 416applications built for the same architecture. 417This is currently limited to the alpha port. 418.It Cd options COMPAT_NOMID 419Enable compatibility with 420.Xr a.out 5 421executables that lack a machine ID. 422This includes 423.Nx 0.8 Ns 's 424ZMAGIC format, and 386BSD and BSDI's 425QMAGIC, NMAGIC, and OMAGIC 426.Xr a.out 5 427formats. 428.It Cd options COMPAT_NETBSD32 429On those architectures that support it, this enables binary 430compatibility with 32-bit applications built for the same architecture. 431This is currently limited to the amd64 and sparc64 ports, and only 432applicable for 64-bit kernels. 433.It Cd options COMPAT_SVR4_32 434On those architectures that support it, this enables binary 435compatibility with 32-bit SVR4 applications built for the same architecture. 436This is currently limited to the sparc64 port, and only applicable for 43764-bit kernels. 438.It Cd options COMPAT_AOUT_M68K 439On m68k architectures which have switched to ELF, 440this enables binary compatibility with 441.Nx Ns Tn /m68k 442.Xr a.out 5 443executables on 444.Nx Ns Tn /m68k 445ELF kernels. 446This handles alignment incompatibility of m68k ABI between 447a.out and ELF which causes the structure padding differences. 448Currently only some system calls which use 449.Va struct stat 450are adjusted and some binaries which use 451.Xr sysctl 3 452to retrieve network details would not work properly. 453.It Cd options EXEC_ELF_NOTELESS 454Run unidentified ELF binaries as 455.Nx 456binaries. 457This might be needed for very old 458.Nx 459ELF binaries on some archs. 460These old binaries didn't contain an appropriate 461.Li .note.netbsd.ident 462section, and thus can't be identified by the kernel as 463.Nx 464binaries otherwise. 465Beware - if this option is on, the kernel would run 466.Em any 467unknown ELF binaries as if they were 468.Nx 469binaries. 470.It Cd options P1003_1B_SEMAPHORE 471Includes kernel support for the standard C library 472.Pq libc 473functions that implement semaphores as specified in 474.St -p1003.1-96 . 475.El 476.Ss Debugging Options 477.Bl -ohang 478.It Cd options DDB 479Compiles in a kernel debugger for diagnosing kernel problems. 480See 481.Xr ddb 4 482for details. 483.Em NOTE : 484not available on all architectures. 485.It Cd options DDB_FROMCONSOLE=integer 486If set to non-zero, DDB may be entered by sending a break on a serial 487console or by a special key sequence on a graphics console. 488A value of "0" ignores console breaks or key sequences. 489If not explicitly specified, the default value is "1". 490Note that this sets the value of the 491.Em ddb.fromconsole 492.Xr sysctl 3 493variable which may be changed at run time -- see 494.Xr sysctl 8 495for details. 496.It Cd options DDB_HISTORY_SIZE=integer 497If this is non-zero, enable history editing in the kernel debugger 498and set the size of the history to this value. 499.It Cd options DDB_ONPANIC 500The default if not specified is 501.Dq 1 502- just enter into DDB. 503If set to 504.Dq 2 505the kernel will 506attempt to print out a stack trace before entering into DDB. 507If set to 508.Dq 0 509the kernel will attempt to print out a stack trace 510and reboot the system. 511If set to 512.Dq -1 513then neither a stack trace is printed or DDB entered - 514it is as if DDB were not compiled into the kernel. 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_COMMANDONENTER=string 522This option specify commands which will be executed on each entry to DDB. 523This sets the default value of the 524.Em ddb.commandonenter 525.Xr sysctl 3 526variable which may be changed at run time. 527.It Cd options DDB_BREAK_CHAR=integer 528This option overrides using break to enter the kernel debugger 529on the serial console. 530The value given is the ASCII value to be used instead. 531This is currently only supported by the com driver. 532.It Cd options DDB_VERBOSE_HELP 533This option adds more verbose descriptions to the 534.Em help 535command. 536.It Cd options KGDB 537Compiles in a remote kernel debugger stub for diagnosing kernel problems 538using the 539.Dq remote target 540feature of gdb. 541See 542.Xr gdb 1 543for details. 544.Em NOTE : 545not available on all architectures. 546.It Cd options KGDB_DEV 547Device number 548.Po 549as a 550.Dv dev_t 551.Pc 552of kgdb device. 553.It Cd options KGDB_DEVADDR 554Memory address of kgdb device. 555.It Cd options KGDB_DEVMODE 556Permissions of kgdb device. 557.It Cd options KGDB_DEVNAME 558Device name of kgdb device. 559.It Cd options KGDB_DEVRATE 560Baud rate of kgdb device. 561.It Cd makeoptions DEBUG="-g" 562The 563.Fl g 564flag causes 565.Pa netbsd.gdb 566to be built in addition to 567.Pa netbsd . 568.Pa netbsd.gdb 569is useful for debugging kernel crash dumps with gdb. 570See 571.Xr gdb 1 572for details. 573This also turns on 574.Em options DEBUG 575(which see). 576.It Cd options DEBUG 577Turns on miscellaneous kernel debugging. 578Since options are turned into preprocessor defines (see above), 579.Em options DEBUG 580is equivalent to doing a 581.Em #define DEBUG 582throughout the kernel. 583Much of the kernel has 584.Em #ifdef DEBUG 585conditionalized debugging code. 586Note that many parts of the kernel (typically device drivers) include their own 587.Em #ifdef XXX_DEBUG 588conditionals instead. 589This option also turns on certain other options, 590which may decrease system performance. 591.It Cd options DIAGNOSTIC 592Adds code to the kernel that does internal consistency checks. 593This code will cause the kernel to panic if corruption of internal data 594structures is detected. 595These checks can decrease performance up to 15%. 596.It Cd options LOCKDEBUG 597Adds code to the kernel to detect incorrect use of locking primitives 598(mutex, rwlock, simplelock). 599This code will cause the kernel to check for dead lock conditions. 600It will also check for memory being freed to not contain initialised 601lock primitives. 602Functions for use in 603.Xr ddb 4 604to check lock chains etc. are also enabled. 605These checks are very expensive and can decrease performance on 606multi-processor machines by a factor of three. 607.It Cd options KSTACK_CHECK_MAGIC 608Check kernel stack usage and panic if stack overflow is detected. 609This check is performance sensitive because it scans stack on each context 610switch. 611.It Cd options KTRACE 612Add hooks for the system call tracing facility, which allows users to 613watch the system call invocation behavior of processes. 614See 615.Xr ktrace 1 616for details. 617.It Cd options MSGBUFSIZE=integer 618This option sets the size of the kernel message buffer. 619This buffer holds the kernel output of 620.Fn printf 621when not (yet) read by 622.Xr syslogd 8 . 623This is particularly useful when the system has crashed and you wish to lookup 624the kernel output from just before the crash. 625Also, since the autoconfig output becomes more and more verbose, 626it sometimes happens that the message buffer overflows before 627.Xr syslogd 8 628was able to read it. 629Note that not all systems are capable of obtaining a variable sized message 630buffer. 631There are also some systems on which memory contents are not preserved 632across reboots. 633.It Cd options MALLOCLOG 634Enables an event log for 635.Xr malloc 9 . 636Useful for tracking down 637.Dq Data modified on freelist 638and 639.Dq multiple free 640problems. 641.It Cd options MALLOCLOGSIZE=integer 642Defines the number of entries in the malloc log. 643Default is 100000 entries. 644.It Cd options UVMHIST 645Enables the UVM history logs, which create in-memory traces of 646various UVM activities. 647These logs can be displayed be calling 648.Fn uvmhist_dump 649or 650.Fn uvm_hist 651with appropriate arguments from DDB. 652See the kernel source file sys/uvm/uvm_stat.c for details. 653.It Cd options UVMHIST_PRINT 654Prints the UVM history logs on the system console as entries are added. 655Note that the output is 656.Em extremely 657voluminous, so this option is really only useful for debugging 658the very earliest parts of kernel initialization. 659.El 660.Ss File Systems 661.Bl -ohang 662.It Cd file-system FFS 663Includes code implementing the Berkeley Fast File System 664.Po Em FFS Pc . 665Most machines need this if they are not running diskless. 666.It Cd file-system EXT2FS 667Includes code implementing the Second Extended File System 668.Po Em ext2 Pc , 669revision 0 and revision 1 with the 670.Em filetype , 671.Em sparse_super 672and 673.Em large_file 674options. 675This is the most commonly used file system on the Linux operating system, 676and is provided here for compatibility. 677Some of the specific features of 678.Em ext2 679like the "behavior on errors" are not implemented. 680See 681.Xr mount_ext2fs 8 682for details. 683.It Cd file-system LFS 684.Bq Em EXPERIMENTAL 685Include the Log-structured File System 686.Po Em LFS Pc . 687See 688.Xr mount_lfs 8 689and 690.Xr newfs_lfs 8 691for details. 692.It Cd file-system MFS 693Include the Memory File System 694.Po Em MFS Pc . 695This file system stores files in swappable memory, and produces 696notable performance improvements when it is used as the file store 697for 698.Pa /tmp 699and similar file systems. 700See 701.Xr mount_mfs 8 702for details. 703.It Cd file-system NFS 704Include the client side of the Network File System 705.Pq Tn NFS 706remote file sharing protocol. 707Although the bulk of the code implementing 708.Tn NFS 709is kernel based, several user level daemons are needed for it to work. 710See 711.Xr mount_nfs 8 712for details. 713.It Cd file-system CD9660 714Includes code for the 715.Tn ISO 7169660 + Rock Ridge file system, which is the standard file system on many 717.Tn CD-ROM 718discs. 719Useful primarily if you have a 720.Tn CD-ROM 721drive. 722See 723.Xr mount_cd9660 8 724for details. 725.It Cd file-system MSDOSFS 726Includes the 727.Tn MS-DOS 728FAT file system, which is reportedly still used 729by unfortunate people who have not heard about 730.Nx . 731Also implements the 732.Tn Windows 95 733extensions to the same, which permit the use of longer, mixed case 734file names. 735See 736.Xr mount_msdos 8 737and 738.Xr fsck_msdos 8 739for details. 740.It Cd file-system NTFS 741.Bq Em EXPERIMENTAL 742Includes code for the 743.Tn Microsoft Windows NT 744file system. 745See 746.Xr mount_ntfs 8 747for details. 748.It Cd file-system FDESC 749Includes code for a file system, conventionally mounted on 750.Pa /dev/fd , 751which permits access to the per-process file descriptor space via 752special files in the file system. 753See 754.Xr mount_fdesc 8 755for details. 756Note that this facility is redundant, and thus unneeded on most 757.Nx 758systems, since the 759.Xr fd 4 760pseudo-device driver already provides identical functionality. 761On most 762.Nx 763systems, instances of 764.Xr fd 4 765are mknoded under 766.Pa /dev/fd/ 767and on 768.Pa /dev/stdin , 769.Pa /dev/stdout , 770and 771.Pa /dev/stderr . 772.It Cd file-system KERNFS 773Includes code which permits the mounting of a special file system 774(normally mounted on 775.Pa /kern ) 776in which files representing various kernel variables and parameters 777may be found. 778See 779.Xr mount_kernfs 8 780for details. 781.It Cd file-system NULLFS 782Includes code for a loopback file system. 783This permits portions of the file hierarchy to be re-mounted in other places. 784The code really exists to provide an example of a stackable file system layer. 785See 786.Xr mount_null 8 787for details. 788.It Cd file-system OVERLAY 789Includes code for a file system filter. 790This permits the overlay file system to intercept all access to an underlying 791file system. 792This file system is intended to serve as an example of a stacking file 793system which has a need to interpose itself between an underlying file 794system and all other access. 795See 796.Xr mount_overlay 8 797for details. 798.It Cd file-system PROCFS 799Includes code for a special file system (conventionally mounted on 800.Pa /proc ) 801in which the process space becomes visible in the file system. 802Among 803other things, the memory spaces of processes running on the system are 804visible as files, and signals may be sent to processes by writing to 805.Pa ctl 806files in the procfs namespace. 807See 808.Xr mount_procfs 8 809for details. 810.It Cd file-system UDF 811.Bq Em EXPERIMENTAL 812Includes code for the UDF file system commonly found on CD and DVD 813media but also more and more on USB sticks. 814Useful primarily if you have a CD or a DVD drive, be it a read-only 815or a rewritable device. 816Currently only supports read-access. 817See 818.Xr mount_udf 8 819for details. 820.It Cd file-system UMAPFS 821Includes a loopback file system in which user and group IDs may be 822remapped -- this can be useful when mounting alien file systems with 823different UIDs and GIDs than the local system. 824See 825.Xr mount_umap 8 826for details. 827.It Cd file-system UNION 828.Bq Em EXPERIMENTAL 829Includes code for the union file system, which permits directories to 830be mounted on top of each other in such a way that both file systems 831remain visible -- this permits tricks like allowing writing (and the 832deleting of files) on a read-only file system like a 833.Tn CD-ROM 834by mounting a local writable file system on top of the read-only file system. 835See 836.Xr mount_union 8 837for details. 838.It Cd file-system CODA 839.Bq Em EXPERIMENTAL 840Includes code for the Coda file system. 841Coda is a distributed file system like NFS and AFS. 842It is freely available, like NFS, but it functions much like AFS in being a 843.Dq stateful 844file system. 845Both Coda and AFS cache files on your local machine to improve performance. 846Then Coda goes a step further than AFS by letting you access the cached 847files when there is no available network, viz. disconnected laptops and 848network outages. 849In Coda, both the client and server are outside the kernel which makes 850them easier to experiment with. 851Coda is available for several UNIX and non-UNIX platforms. 852See http://www.coda.cs.cmu.edu for more details. 853.Em NOTE : 854You also need to enable the pseudo-device, vcoda, for the Coda 855file system to work. 856.It Cd file-system SMBFS 857.Bq Em EXPERIMENTAL 858Includes code for the SMB/CIFS file system. 859See 860.Xr mount_smbfs 8 861for details. 862.Em NOTE : 863You also need to enable the pseudo-device, nsmb, for the SMB 864file system to work. 865.It Cd file-system PTYFS 866.Bq Em EXPERIMENTAL 867Includes code for a special file system (normally mounted on 868.Pa /dev/pts ) 869in which pseudo-terminal slave devices become visible in the file system. 870See 871.Xr mount_ptyfs 8 872for details. 873.It Cd file-system TMPFS 874Includes code for the efficient memory file system, normally used over 875.Pa /tmp . 876See 877.Xr mount_tmpfs 8 878for details. 879.It Cd file-system PUFFS 880Includes kernel support for the pass-to-userspace framework file system. 881It can be used to implement file system functionality in userspace. 882See 883.Xr puffs 3 884for more details. 885This enables for example sshfs: 886.Xr mount_psshfs 8 . 887.El 888.Ss File System Options 889.Bl -ohang 890.It Cd options MAGICLINKS 891Enables the expansion of special strings 892.Po 893beginning with 894.Dq @ 895.Pc 896when traversing symbolic links. 897See 898.Xr symlink 7 899for a list of supported strings. 900Note that this option only controls the enabling of this feature 901by the kernel at boot-up. 902This feature can still be manipulated with the 903.Xr sysctl 8 904command regardless of the setting of this option. 905.It Cd options NFSSERVER 906Include the server side of the 907.Em NFS 908(Network File System) remote file sharing protocol. 909Although the bulk of the code implementing 910.Em NFS 911is kernel based, several user level daemons are needed for it to 912work. 913See 914.Xr mountd 8 915and 916.Xr nfsd 8 917for details. 918.It Cd options QUOTA 919Enables kernel support for file system quotas. 920See 921.Xr quotaon 8 , 922.Xr edquota 8 , 923and 924.Xr quota 1 925for details. 926Note that quotas only work on 927.Dq ffs 928file systems, although 929.Xr rpc.rquotad 8 930permits them to be accessed over 931.Em NFS . 932.It Cd options QUOTA2 933Enables kernel support for the new file system quotas format. 934See 935.Xr tunefs 8 , 936.Xr newfs 8 , 937.Xr mount_mfs 8 , 938.Xr edquota 8 , 939and 940.Xr quota 1 941for details. 942Note that quota2 is only supported by 943.Dq ffs 944and 945.Dq mfs 946file systems at this time. 947.It Cd options FFS_EI 948Enable ``Endian-Independent'' FFS support. 949This allows a system to mount an FFS file system created for another 950architecture, at a small performance cost for all FFS file systems. 951See also 952.Xr newfs 8 , 953.Xr fsck_ffs 8 , 954.Xr dumpfs 8 955for file system byte order status and manipulation. 956.It Cd options FFS_NO_SNAPSHOT 957Disable the 958.Dq file system snapshot 959support in FFS file systems. 960Maybe useful for install media kernels, small memory systems and 961embedded systems which don't require the snapshot support. 962.It Cd options UFS_EXTATTR 963Enable extended attribute support for UFS1 filesystems. 964.It Cd options WAPBL 965Enable 966.Dq Write Ahead Physical Block Logging file system journaling . 967This provides rapid file system consistency checking after a system outage. 968It also provides better general use performance over regular FFS. 969See also 970.Xr wapbl 4 . 971.It Cd options NVNODE=integer 972This option sets the size of the cache used by the name-to-inode translation 973routines, (a.k.a. the 974.Fn namei 975cache, though called by many other names in the kernel source). 976By default, this cache has 977.Dv NPROC 978(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 979A reasonable way to derive a value of 980.Dv NVNODE , 981should you notice a large number of namei cache misses with a tool such as 982.Xr systat 1 , 983is to examine your system's current computed value with 984.Xr sysctl 8 , 985(which calls this parameter "kern.maxvnodes") and to increase this value 986until either the namei cache hit rate improves or it is determined that 987your system does not benefit substantially from an increase in the size of 988the namei cache. 989.It Cd options NAMECACHE_ENTER_REVERSE 990Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 991as well as a normal one. 992Normally, this is already done for directory vnodes, to speed up the getcwd 993operation. 994This option will cause longer hash chains in the reverse cache, and thus 995slow down getcwd somewhat. 996However, it does make vnode -\*[Gt] path translations possible in some cases. 997For now, only useful if strict /proc/#/maps emulation for Linux binaries is 998required. 999.It Cd options EXT2FS_SYSTEM_FLAGS 1000This option changes the behavior of the APPEND and IMMUTABLE flags 1001for a file on an 1002.Em ext2 1003file system. 1004Without this option, the superuser or owner of the file can 1005set and clear them. 1006With this option, only the superuser can set them, and 1007they can't be cleared if the securelevel is greater than 0. 1008See also 1009.Xr chflags 1 1010and 1011.Xr secmodel_securelevel 9 . 1012.It Cd options NFS_BOOT_BOOTP 1013Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1014information if NFS is used to mount the root file system. 1015See 1016.Xr diskless 8 1017for details. 1018.It Cd options NFS_BOOT_DHCP 1019Same as 1020.Dq NFS_BOOT_BOOTP , 1021but use the DHCP extensions to the 1022BOOTP protocol (RFC 1541). 1023.It Cd options NFS_BOOT_BOOTP_REQFILE 1024Specifies the string sent in the bp_file field of the BOOTP / DHCP 1025request packet. 1026.It Cd options NFS_BOOT_BOOTPARAM 1027Enable use of the BOOTPARAM protocol, consisting of RARP and 1028BOOTPARAM RPC, to get configuration information if NFS 1029is used to mount the root file system. 1030See 1031.Xr diskless 8 1032for details. 1033.It Cd options NFS_BOOT_RWSIZE=value 1034Set the initial NFS read and write sizes for diskless-boot requests. 1035The normal default is 8Kbytes. 1036This option provides a way to lower the value (e.g., to 1024 bytes) 1037as a workaround for buggy network interface cards or boot PROMs. 1038Once booted, the read and write request sizes can be increased by 1039remounting the file system. 1040See 1041.Xr mount_nfs 8 1042for details. 1043.It Cd options NFS_V2_ONLY 1044Reduce the size of the NFS client code by omitting code that's only required 1045for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1046servers. 1047.It Cd options UFS_DIRHASH 1048Increase lookup performance by maintaining in-core hash tables 1049for large directories. 1050.El 1051.Ss Buffer queue strategy options 1052The following options enable alternative buffer queue strategies. 1053.Bl -ohang 1054.It Cd options BUFQ_READPRIO 1055Enable experimental buffer queue strategy for disk I/O. 1056In the default strategy, outstanding disk requests are ordered by 1057sector number and sent to the disk, regardless of whether the 1058operation is a read or write; this option gives priority to issuing 1059read requests over write requests. 1060Although requests may therefore be issued out of sector-order, causing 1061more seeks and thus lower overall throughput, interactive system 1062responsiveness under heavy disk I/O load may be improved, as processes 1063blocking on disk reads are serviced sooner (file writes typically 1064don't cause applications to block). 1065The performance effect varies greatly depending on the hardware, drive 1066firmware, file system configuration, workload, and desired performance 1067trade-off. 1068Systems using drive write-cache (most modern IDE disks, by default) 1069are unlikely to benefit and may well suffer; such disks acknowledge 1070writes very quickly, and optimize them internally according to 1071physical layout. 1072Giving these disks as many requests to work with as possible (the 1073standard strategy) will typically produce the best results, especially 1074if the drive has a large cache; the drive will silently complete 1075writes from cache as it seeks for reads. 1076Disks that support a large number of concurrent tagged requests (SCSI 1077disks and many hardware RAID controllers) expose this internal 1078scheduling with tagged responses, and don't block for reads; such 1079disks may not see a noticeable difference with either strategy. 1080However, if IDE disks are run with write-cache disabled for safety, 1081writes are not acknowledged until actually completed, and only one 1082request can be outstanding; a large number of small writes in one 1083locality can keep the disk busy, starving reads elsewhere on the disk. 1084Such systems are likely to see the most benefit from this option. 1085Finally, the performance interaction of this option with ffs soft 1086dependencies can be subtle, as that mechanism can drastically alter 1087the workload for file system metadata writes. 1088.It Cd options BUFQ_PRIOCSCAN 1089Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1090.It Cd options NEW_BUFQ_STRATEGY 1091Synonym of 1092.Em BUFQ_READPRIO . 1093.El 1094.Ss Miscellaneous Options 1095.Bl -ohang 1096.It Cd options MEMORY_DISK_DYNAMIC 1097This option makes the 1098.Xr md 4 1099.Tn RAM 1100disk size dynamically sized. 1101It is incompatible with 1102.Xr mdsetimage 8 . 1103.It Cd options MEMORY_DISK_HOOKS 1104This option allows for some machine dependent functions to be called when 1105the 1106.Xr md 4 1107.Tn RAM 1108disk driver is configured. 1109This can result in automatically loading a 1110.Tn RAM 1111disk from floppy on open (among other things). 1112.It Cd options MEMORY_DISK_IS_ROOT 1113Forces the 1114.Xr md 4 1115.Tn RAM 1116disk to be the root device. 1117This can only be overridden when 1118the kernel is booted in the 'ask-for-root' mode. 1119.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1120Allocates the given number of 512 byte blocks as memory for the 1121.Xr md 4 1122.Tn RAM 1123disk, to be populated with 1124.Xr mdsetimage 8 . 1125.It Cd options MEMORY_DISK_SERVER=0 1126Do not include the interface to a userland memory disk server process. 1127Per default, this option is set to 1, including the support code. 1128Useful for install media kernels. 1129.It Cd options MEMORY_DISK_RBFLAGS=value 1130This option sets the 1131.Xr reboot 2 1132flags used when booting with a memory disk as root file system. 1133Possible values include 1134.Dv RB_AUTOBOOT 1135(boot in the usual fashion - default value), and 1136.Dv RB_SINGLE 1137(boot in single-user mode). 1138.It Cd options MODULAR 1139Enables the framework for kernel modules (see 1140.Xr module 7 ) . 1141.It Cd options VND_COMPRESSION 1142Enables the 1143.Xr vnd 4 1144driver to also handle compressed images. 1145See 1146.Xr vndcompress 1 , 1147.Xr vnd 4 1148and 1149.Xr vnconfig 8 1150for more information. 1151.It Cd options SPLDEBUG 1152Help the kernel programmer find bugs related to the interrupt priority 1153level. 1154When 1155.Fn spllower 1156or 1157.Fn splraise 1158changes the current CPU's interrupt priority level to or from 1159.Dv IPL_HIGH , 1160record a backtrace. 1161Read 1162.Xr return_address 9 1163for caveats about collecting backtraces. 1164This feature is experimental, and it is only available on i386. 1165See 1166.Pa sys/kern/subr_spldebug.c . 1167.It Cd options TFTPROOT 1168Download the root memory disk through TFTP at root mount time. 1169This enables the use of a root 1170.Tn RAM 1171disk without requiring it to be embedded in the kernel using 1172.Xr mdsetimage 8 . 1173The 1174.Tn RAM 1175disk name is obtained using DHCP's filename parameter. 1176This option requires 1177.Em MEMORY_DISK_HOOKS , 1178.Em MEMORY_DISK_DYNAMIC , 1179and 1180.Em MEMORY_DISK_IS_ROOT . 1181It is incompatible with 1182.Em MEMORY_DISK_ROOT_SIZE . 1183.It Cd options MALLOC_NOINLINE 1184Time critical fixed size memory allocation is performed with 1185.Fn MALLOC 1186and 1187.Fn FREE . 1188Normally these expand to inline code, but with 1189.Em MALLOC_NOINLINE 1190these call the normal 1191.Fn malloc 1192and 1193.Fn free 1194functions. 1195Useful for install media kernels, small memory systems and embedded systems. 1196.It Cd options HZ=integer 1197On ports that support it, set the system clock frequency (see 1198.Xr hz 9 ) 1199to the supplied value. 1200Handle with care. 1201.It Cd options NTP 1202Turns on in-kernel precision timekeeping support used by software 1203implementing 1204.Em NTP 1205(Network Time Protocol, RFC 1305). 1206The 1207.Em NTP 1208option adds an in-kernel Phase-Locked Loop (PLL) for normal 1209.Em NTP 1210operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1211operation. 1212.Xr ntpd 8 1213will employ a user-level PLL when kernel support is unavailable, 1214but the in-kernel version has lower latency and more precision, and 1215so typically keeps much better time. 1216.Pp 1217The interface to the kernel 1218.Em NTP 1219support is provided by the 1220.Xr ntp_adjtime 2 1221and 1222.Xr ntp_gettime 2 1223system calls, which are intended for use by 1224.Xr ntpd 8 1225and are enabled by the option. 1226On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1227is not an integer, the 1228.Em NTP 1229option also enables extended-precision arithmetic to keep track of 1230fractional clock ticks at NTP time-format precision. 1231.It Cd options PPS_SYNC 1232This option enables a kernel serial line discipline for receiving time 1233phase signals from an external reference clock such as a radio clock. 1234.Po 1235The 1236.Em NTP 1237option (which see) must be on if the 1238.Em PPS_SYNC 1239option is used 1240.Pc . 1241Some reference clocks generate a Pulse Per Second (PPS) signal in 1242phase with their time source. 1243The 1244.Em PPS 1245line discipline receives this signal on either the data leads 1246or the DCD control lead of a serial port. 1247.Pp 1248.Em NTP 1249uses the PPS signal to discipline the local clock oscillator to a high 1250degree of precision (typically less than 50 microseconds in time and 12510.1 ppm in accuracy). 1252.Em PPS 1253can also generate a serial output pulse when the system receives a PPS 1254interrupt. 1255This can be used to measure the system interrupt latency and thus calibrate 1256.Em NTP 1257to account for it. 1258Using 1259.Em PPS 1260usually requires a gadget box 1261to convert from 1262.Tn TTL 1263to 1264.Tn RS-232 1265signal levels. 1266The gadget box and PPS are described in more detail in the HTML documentation 1267for 1268.Xr ntpd 8 1269in 1270.Pa /usr/share/doc/html/ntp . 1271.Pp 1272.Nx 1273currently supports this option in 1274.Xr com 4 1275and 1276.Xr zsc 4 . 1277.It Cd options SETUIDSCRIPTS 1278Allows scripts with the setuid bit set to execute as the effective 1279user rather than the real user, just like binary executables. 1280.Pp 1281.Em NOTE : 1282Using this option will also enable 1283.Em options FDSCRIPTS 1284.It Cd options FDSCRIPTS 1285Allows execution of scripts with the execute bit set, but not the 1286read bit, by opening the file and passing the file descriptor to 1287the shell, rather than the filename. 1288.Pp 1289.Em NOTE : 1290Execute only (non-readable) scripts will have 1291.Va argv[0] 1292set to 1293.Pa /dev/fd/* . 1294What this option allows as far as security is 1295concerned, is the ability to safely ensure that the correct script 1296is run by the interpreter, as it is passed as an already open file. 1297.It Cd options PUCCN 1298Enables treating serial ports found on PCI boards 1299.Xr puc 4 1300as potential console devices. 1301The method for choosing such a console device is port dependent. 1302.It Cd options RTC_OFFSET=integer 1303The kernel (and typically the hardware battery backed-up clock on 1304those machines that have one) keeps time in 1305.Em UTC 1306(Universal Coordinated Time, once known as 1307.Em GMT , 1308or Greenwich Mean Time) 1309and not in the time of the local time zone. 1310The 1311.Em RTC_OFFSET 1312option is used on some ports (such as the i386) to tell the kernel 1313that the hardware clock is offset from 1314.Em UTC 1315by the specified number of minutes. 1316This is typically used when a machine boots several operating 1317systems and one of them wants the hardware clock to run in the 1318local time zone and not in 1319.Em UTC , 1320e.g. 1321.Em RTC_OFFSET=300 1322means 1323the hardware clock is set to US Eastern Time (300 minutes behind 1324.Em UTC ) , 1325and not 1326.Em UTC . 1327(Note: 1328.Em RTC_OFFSET 1329is used to initialize a kernel variable named 1330.Va rtc_offset 1331which is the source actually used to determine the clock offset, and 1332which may be accessed via the kern.rtc_offset sysctl variable. 1333See 1334.Xr sysctl 8 1335and 1336.Xr sysctl 3 1337for details. 1338Since the kernel clock is initialized from the hardware clock very 1339early in the boot process, it is not possible to meaningfully change 1340.Va rtc_offset 1341in system initialization scripts. 1342Changing this value currently may only be done at kernel compile 1343time or by patching the kernel and rebooting). 1344.Pp 1345.Em NOTE : 1346Unfortunately, in many cases where the hardware clock 1347is kept in local time, it is adjusted for Daylight Savings 1348Time; this means that attempting to use 1349.Em RTC_OFFSET 1350to let 1351.Nx 1352coexist with such an operating system, like Windows, 1353would necessitate changing 1354.Em RTC_OFFSET 1355twice a year. 1356As such, this solution is imperfect. 1357.It Cd options KMEMSTATS 1358The kernel memory allocator, 1359.Xr malloc 9 , 1360will keep statistics on its performance if this option is enabled. 1361Unfortunately, this option therefore essentially disables the 1362.Fn MALLOC 1363and 1364.Fn FREE 1365forms of the memory allocator, which are used to enhance the performance 1366of certain critical sections of code in the kernel. 1367This option therefore can lead to a significant decrease in the 1368performance of certain code in the kernel if enabled. 1369Examples of such code include the 1370.Fn namei 1371routine, the 1372.Xr ccd 4 1373driver, 1374and much of the networking code. 1375.It Cd options MAXUPRC=integer 1376Sets the soft 1377.Dv RLIMIT_NPROC 1378resource limit, which specifies the maximum number of simultaneous 1379processes a user is permitted to run, for process 0; 1380this value is inherited by its child processes. 1381It defaults to 1382.Em CHILD_MAX , 1383which is currently defined to be 160. 1384Setting 1385.Em MAXUPRC 1386to a value less than 1387.Em CHILD_MAX 1388is not permitted, as this would result in a violation of the semantics of 1389.St -p1003.1-90 . 1390.It Cd options NOFILE=integer 1391Sets the soft 1392.Dv RLIMIT_NOFILE 1393resource limit, which specifies the maximum number of open 1394file descriptors for each process; 1395this value is inherited by its child processes. 1396It defaults to 1397.Em OPEN_MAX , 1398which is currently defined to be 64. 1399.It Cd options MAXFILES=integer 1400Sets the default value of the 1401.Em kern.maxfiles 1402sysctl variable, which indicates the maximum number of files that may 1403be open in the system. 1404.It Cd options DEFCORENAME=string 1405Sets the default value of the 1406.Em kern.defcorename 1407sysctl variable, otherwise it is set to 1408.Nm %n.core . 1409See 1410.Xr sysctl 8 1411and 1412.Xr sysctl 3 1413for details. 1414.It Cd options RASOPS_CLIPPING 1415Enables clipping within the 1416.Nm rasops 1417raster-console output system. 1418.Em NOTE : 1419only available on architectures that use 1420.Nm rasops 1421for console output. 1422.It Cd options RASOPS_SMALL 1423Removes optimized character writing code from the 1424.Nm rasops 1425raster-console output system. 1426.Em NOTE : 1427only available on architectures that use 1428.Nm rasops 1429for console output. 1430.It Cd options INCLUDE_CONFIG_FILE 1431Embeds the kernel config file used to define the kernel in the kernel 1432binary itself. 1433The embedded data also includes any files directly included by the config 1434file itself, e.g. 1435.Pa GENERIC.local 1436or 1437.Pa std.$MACHINE . 1438The embedded config file can be extracted from the resulting kernel with 1439.Xr config 1 1440.Fl x , 1441or by the following command: 1442.Bd -literal -offset indent 1443strings netbsd | sed -n 's/^_CFG_//p' | unvis 1444.Ed 1445.It Cd options INCLUDE_JUST_CONFIG 1446Similar to the above option, but includes just the actual config file, 1447not any included files. 1448.It Cd options PIPE_SOCKETPAIR 1449Use slower, but smaller socketpair(2)-based pipe implementation instead 1450of default faster, but bigger one. 1451Primarily useful for installation kernels. 1452.It Cd options USERCONF 1453Compiles in the in-kernel device configuration manager. 1454See 1455.Xr userconf 4 1456for details. 1457.It Cd options PERFCTRS 1458Compiles in kernel support for CPU performance-monitoring counters. 1459See 1460.Xr pmc 1 1461for details. 1462.Em NOTE : 1463not available on all architectures. 1464.It Cd options SYSCALL_STATS 1465Count the number of times each system call number is called. 1466The values can be read through the sysctl interface and displayed using 1467.Xr systat 1 . 1468.Em NOTE : 1469not yet available on all architectures. 1470.It Cd options SYSCALL_TIMES 1471Count the time spent (using 1472.Fn cpu_counter32 ) 1473in each system call. 1474.Em NOTE : 1475Using this option will also enable 1476.Cd options SYSCALL_STATS . 1477.It Cd options SYSCALL_TIMES_HASCOUNTER 1478Force use of 1479.Fn cpu_counter32 1480even if 1481.Fn cpu_hascounter 1482reports false. 1483Useful for systems where the cycle counter doesn't run at a constant rate 1484(e.g. Soekris boxes). 1485.It Cd options XSERVER_DDB 1486A supplement to XSERVER that adds support for entering 1487.Xr ddb 4 1488while in 1489.Tn X11 . 1490.It Cd options FILEASSOC 1491Support for 1492.Xr fileassoc 9 . 1493.It Cd options FILEASSOC_NHOOKS=integer 1494Number of storage slots per file for 1495.Xr fileassoc 9 . 1496Default is 4. 1497.El 1498.Ss Networking Options 1499.Bl -ohang 1500.It Cd options GATEWAY 1501Enables 1502.Em IPFORWARDING 1503(which see) 1504and (on most ports) increases the size of 1505.Em NMBCLUSTERS 1506(which see). 1507In general, 1508.Em GATEWAY 1509is used to indicate that a system should act as a router, and 1510.Em IPFORWARDING 1511is not invoked directly. 1512(Note that 1513.Em GATEWAY 1514has no impact on protocols other than 1515.Tn IP , 1516such as 1517.Tn CLNP ) . 1518.Em GATEWAY 1519option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1520.It Cd options ICMPPRINTFS 1521The 1522.Em ICMPPRINTFS 1523option will enable debugging information to be printed about 1524the 1525.Xr icmp 4 1526protocol. 1527.It Cd options IPFORWARDING=value 1528If 1529.Em value 1530is 1 this enables IP routing behavior. 1531If 1532.Em value 1533is 0 (the default), it disables it. 1534The 1535.Em GATEWAY 1536option sets this to 1 automatically. 1537With this option enabled, the machine will forward IP datagrams destined 1538for other machines between its interfaces. 1539Note that even without this option, the kernel will 1540still forward some packets (such as source routed packets) -- removing 1541.Em GATEWAY 1542and 1543.Em IPFORWARDING 1544is insufficient to stop all routing through a bastion host on a 1545firewall -- source routing is controlled independently. 1546To turn off source routing, use 1547.Em options IPFORWSRCRT=0 1548(which see). 1549Note that IP forwarding may be turned on and off independently of the 1550setting of the 1551.Em IPFORWARDING 1552option through the use of the 1553.Em net.inet.ip.forwarding 1554sysctl variable. 1555If 1556.Em net.inet.ip.forwarding 1557is 1, IP forwarding is on. 1558See 1559.Xr sysctl 8 1560and 1561.Xr sysctl 3 1562for details. 1563.It Cd options IPFORWSRCRT=value 1564If 1565.Em value 1566is set to zero, source routing of IP datagrams is turned off. 1567If 1568.Em value 1569is set to one (the default) or the option is absent, source routed IP 1570datagrams are forwarded by the machine. 1571Note that source routing of IP packets may be turned on and off 1572independently of the setting of the 1573.Em IPFORWSRCRT 1574option through the use of the 1575.Em net.inet.ip.forwsrcrt 1576sysctl variable. 1577If 1578.Em net.inet.ip.forwsrcrt 1579is 1, forwarding of source routed IP datagrams is on. 1580See 1581.Xr sysctl 8 1582and 1583.Xr sysctl 3 1584for details. 1585.It Cd options IFA_STATS 1586Tells the kernel to maintain per-address statistics on bytes sent 1587and received over (currently) Internet and AppleTalk addresses. 1588.\"This can be a fairly expensive operation, so you probably want to 1589.\"keep this disabled. 1590The option is not recommended as it degrades system stability. 1591.It Cd options IFQ_MAXLEN=value 1592Increases the allowed size of the network interface packet queues. 1593The default queue size is 50 packets, and you do not normally need 1594to increase it. 1595.It Cd options IPSELSRC 1596Includes support for source-address selection policies. 1597See 1598.Xr in_getifa 9 . 1599.It Cd options MROUTING 1600Includes support for IP multicast routers. 1601You certainly want 1602.Em INET 1603with this. 1604Multicast routing is controlled by the 1605.Xr mrouted 8 1606daemon. 1607See also option 1608.Cd PIM . 1609.It Cd options PIM 1610Includes support for Protocol Independent Multicast (PIM) routing. 1611You need 1612.Em MROUTING 1613and 1614.Em INET 1615with this. 1616Software using this can be found e.g. in 1617.Pa pkgsrc/net/xorp . 1618.It Cd options INET 1619Includes support for the 1620.Tn TCP/IP 1621protocol stack. 1622You almost certainly want this. 1623See 1624.Xr inet 4 1625for details. 1626.It Cd options INET6 1627Includes support for the 1628.Tn IPv6 1629protocol stack. 1630See 1631.Xr inet6 4 1632for details. 1633Unlike 1634.Em INET , 1635.Em INET6 1636enables multicast routing code as well. 1637This option requires 1638.Em INET 1639at this moment, but it should not. 1640.It Cd options ND6_DEBUG 1641The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1642for debugging IPv6 neighbor discovery protocol handling. 1643See 1644.Xr sysctl 3 1645for details. 1646.It Cd options IPSEC 1647Includes support for the 1648.Tn IPsec 1649protocol, using the KAME implementation. 1650See 1651.Xr ipsec 4 1652for details. 1653.It Cd options IPSEC_DEBUG 1654Enables debugging code in 1655.Tn IPsec 1656stack. 1657See 1658.Xr ipsec 4 1659for details. 1660.It Cd options IPSEC_ESP 1661Includes support for 1662.Tn IPsec 1663.Tn ESP 1664protocol, using the KAME implementation. 1665See 1666.Xr ipsec 4 1667for details. 1668.It Cd options FAST_IPSEC 1669Includes support for the 1670.Tn IPsec 1671protocol, using the implementation derived from 1672.Ox , 1673relaying on 1674.Xr opencrypto 9 1675to carry out cryptographic operations. 1676See 1677.Xr fast_ipsec 4 1678for details. 1679.It Cd options IPSEC_NAT_T 1680Includes support for 1681.Tn IPsec 1682Network Address Translator traversal (NAT-T), as described in RFCs 3947 1683and 3948. 1684This feature might be patent-encumbered in some countries. 1685.It Cd options ALTQ 1686Enabled ALTQ (Alternate Queueing). 1687For simple rate-limiting, use 1688.Xr tbrconfig 8 1689to set up the interface transmission rate. 1690To use queueing disciplines, their appropriate kernel options should also 1691be defined (documented below). 1692Queueing disciplines are managed by 1693.Xr altqd 8 . 1694See 1695.Xr altq 9 1696for details. 1697.It Cd options ALTQ_HFSC 1698Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1699module. 1700HFSC supports both link-sharing and guaranteed real-time services. 1701HFSC employs a service curve based QoS model, and its unique feature 1702is an ability to decouple delay and bandwidth allocation. 1703Requires 1704.Em ALTQ_RED 1705to use the RED queueing discipline on HFSC classes, or 1706.Em ALTQ_RIO 1707to use the RIO queueing discipline on HFSC classes. 1708This option assumes 1709.Em ALTQ . 1710.It Cd options ALTQ_PRIQ 1711Include support for ALTQ-implemented PRIQ (Priority Queueing). 1712PRIQ implements a simple priority-based queueing discipline. 1713A higher priority class is always served first. 1714Requires 1715.Em ALTQ_RED 1716to use the RED queueing discipline on HFSC classes, or 1717.Em ALTQ_RIO 1718to use the RIO queueing discipline on HFSC classes. 1719This option assumes 1720.Em ALTQ . 1721.It Cd options ALTQ_WFQ 1722Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1723WFQ implements a weighted-round robin scheduler for a set of queues. 1724A weight can be assigned to each queue to give a different proportion 1725of the link capacity. 1726A hash function is used to map a flow to one of a set of queues. 1727This option assumes 1728.Em ALTQ . 1729.It Cd options ALTQ_FIFOQ 1730Include support for ALTQ-implemented FIFO queueing. 1731FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1732This option assumes 1733.Em ALTQ . 1734.It Cd options ALTQ_RIO 1735Include support for ALTQ-implemented RIO (RED with In/Out). 1736The original RIO has 2 sets of RED parameters; one for in-profile 1737packets and the other for out-of-profile packets. 1738At the ingress of the network, profile meters tag packets as IN or 1739OUT based on contracted profiles for customers. 1740Inside the network, IN packets receive preferential treatment by 1741the RIO dropper. 1742ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1743PHB of DiffServ (RFC 2597). 1744This option assumes 1745.Em ALTQ . 1746.It Cd options ALTQ_BLUE 1747Include support for ALTQ-implemented Blue buffer management. 1748Blue is another active buffer management mechanism. 1749This option assumes 1750.Em ALTQ . 1751.It Cd options ALTQ_FLOWVALVE 1752Include support for ALTQ-implemented Flowvalve. 1753Flowvalve is a simple implementation of a RED penalty box that identifies 1754and punishes misbehaving flows. 1755This option requires 1756.Em ALTQ_RED 1757and assumes 1758.Em ALTQ . 1759.It Cd options ALTQ_CDNR 1760Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1761packet marking/manipulation. 1762Traffic conditioners are components to meter, mark, or drop incoming 1763packets according to some rules. 1764As opposed to queueing disciplines, traffic conditioners handle incoming 1765packets at an input interface. 1766This option assumes 1767.Em ALTQ . 1768.It Cd options ALTQ_NOPCC 1769Disables use of processor cycle counter to measure time in ALTQ. 1770This option should be defined for a non-Pentium i386 CPU which does not 1771have TSC, SMP (per-CPU counters are not in sync), or power management 1772which affects processor cycle counter. 1773This option assumes 1774.Em ALTQ . 1775.It Cd options ALTQ_IPSEC 1776Include support for IPsec in IPv4 ALTQ. 1777This option assumes 1778.Em ALTQ . 1779.It Cd options ALTQ_JOBS 1780Include support for ALTQ-implemented JoBS (Joint Buffer Management 1781and Scheduling). 1782This option assumes 1783.Em ALTQ . 1784.It Cd options ALTQ_AFMAP 1785Include support for an undocumented ALTQ feature that is used to map an IP 1786flow to an ATM VC (Virtual Circuit). 1787This option assumes 1788.Em ALTQ . 1789.It Cd options ALTQ_LOCALQ 1790Include support for ALTQ-implemented local queues. 1791Its practical use is undefined. 1792Assumes 1793.Em ALTQ . 1794.It Cd options SUBNETSARELOCAL 1795Sets default value for net.inet.ip.subnetsarelocal variable, which 1796controls whether non-directly-connected subnets of connected networks 1797are considered "local" for purposes of choosing the MSS for a TCP 1798connection. 1799This is mostly present for historic reasons and completely irrelevant if 1800you enable Path MTU discovery. 1801.It Cd options HOSTZEROBROADCAST 1802Sets default value for net.inet.ip.hostzerobroadcast variable, which 1803controls whether the zeroth host address of each connected subnet is 1804also considered a broadcast address. 1805Default value is "1", for compatibility with old systems; if this is 1806set to zero on all hosts on a subnet, you should be able to fit an extra 1807host per subnet on the 1808".0" address. 1809.It Cd options MCLSHIFT=value 1810This option is the base-2 logarithm of the size of mbuf clusters. 1811The 1812.Bx 1813networking stack keeps network packets in a linked 1814list, or chain, of kernel buffer objects called mbufs. 1815The system provides larger mbuf clusters as an optimization for 1816large packets, instead of using long chains for large packets. 1817The mbuf cluster size, 1818or 1819.Em MCLBYTES , 1820must be a power of two, and is computed as two raised to the power 1821.Em MCLSHIFT . 1822On systems with Ethernet network adapters, 1823.Em MCLSHIFT 1824is often set to 11, giving 2048-byte mbuf clusters, large enough to 1825hold a 1500-byte 1826.Tn Ethernet 1827frame in a single cluster. 1828Systems with network interfaces supporting larger frame sizes like 1829.Tn ATM , 1830.Tn FDDI , 1831or 1832.Tn HIPPI 1833may perform better with 1834.Em MCLSHIFT 1835set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1836respectively. 1837.It Cd options ISO,TPIP 1838Include support for the ubiquitous 1839.Tn OSI 1840protocol stack. 1841See 1842.Xr iso 4 1843for details. 1844This option assumes 1845.Em INET . 1846.It Cd options EON 1847Include support for tunneling 1848.Tn OSI 1849protocols over 1850.Tn IP . 1851Known to be broken, or at least very fragile, and undocumented. 1852.It Cd options NETATALK 1853Include support for the 1854.Tn AppleTalk 1855protocol stack. 1856The kernel provides provision for the 1857.Em Datagram Delivery Protocol 1858(DDP), providing SOCK_DGRAM support and 1859.Tn AppleTalk 1860routing. 1861This stack is used by the 1862.Em NETATALK 1863package, which adds support for 1864.Tn AppleTalk 1865server services via user libraries and applications. 1866.It Cd options BLUETOOTH 1867Include support for the 1868.Tn Bluetooth 1869protocol stack. 1870See 1871.Xr bluetooth 4 1872for details. 1873.It Cd options IPNOPRIVPORTS 1874Normally, only root can bind a socket descriptor to a so-called 1875.Dq privileged 1876.Tn TCP 1877port, that is, a port number in the range 0-1023. 1878This option eliminates those checks from the kernel. 1879This can be useful if there is a desire to allow daemons without 1880privileges to bind those ports, e.g., on firewalls. 1881The security tradeoffs in doing this are subtle. 1882This option should only be used by experts. 1883.It Cd options TCP_COMPAT_42 1884.Tn TCP 1885bug compatibility with 1886.Bx 4.2 . 1887In 1888.Bx 4.2 , 1889.Tn TCP 1890sequence numbers were 32-bit signed values. 1891Modern implementations of TCP use unsigned values. 1892This option clamps the initial sequence number to start in 1893the range 2^31 rather than the full unsigned range of 2^32. 1894Also, under 1895.Bx 4.2 , 1896keepalive packets must contain at least one byte or else 1897the remote end would not respond. 1898.It Cd options TCP_DEBUG 1899Record the last 1900.Em TCP_NDEBUG 1901TCP packets with SO_DEBUG set, and decode to the console if 1902.Em tcpconsdebug 1903is set. 1904.It Cd options TCP_NDEBUG 1905Number of packets to record for 1906.Em TCP_DEBUG . 1907Defaults to 100. 1908.It Cd options TCP_SENDSPACE=value 1909.It Cd options TCP_RECVSPACE=value 1910These options set the max TCP window size to other sizes than the default. 1911The TCP window sizes can be altered via 1912.Xr sysctl 8 1913as well. 1914.It Cd options TCP_INIT_WIN=value 1915This option sets the initial TCP window size for non-local connections, 1916which is used when the transmission starts. 1917The default size is 1, but if the machine should act more aggressively, 1918the initial size can be set to some other value. 1919The initial TCP window size can be set via 1920.Xr sysctl 8 1921as well. 1922.It Cd options PFIL_HOOKS 1923This option turns on the packet filter interface hooks. 1924See 1925.Xr pfil 9 1926for details. 1927This option assumes 1928.Em INET . 1929.It Cd options IPFILTER_LOG 1930This option, in conjunction with 1931.Em pseudo-device ipfilter , 1932enables logging of IP packets using IP-Filter. 1933.It Cd options IPFILTER_LOOKUP 1934This option enables the 1935IP-Filter 1936.Xr ippool 8 1937functionality to be enabled. 1938.It Cd options IPFILTER_COMPAT 1939This option enables older IP-Filter binaries to work. 1940.It Cd options IPFILTER_DEFAULT_BLOCK 1941This option sets the default policy of IP-Filter. 1942If it is set, IP-Filter will block packets by default. 1943.It Cd options BRIDGE_IPF 1944This option causes 1945.Em bridge 1946devices to use the IP and/or IPv6 filtering hooks, forming 1947a link-layer filter that uses protocol-layer rules. 1948This option assumes the presence of 1949.Em pseudo-device ipfilter . 1950.It Cd options MBUFTRACE 1951This option can help track down mbuf leaks. 1952When enabled, mbufs are tagged with the devices and protocols using them, 1953which slightly decreases network performance. 1954This additional information can be viewed with 1955.Xr netstat 1 : 1956.Dl Ic netstat Fl mssv 1957Not all devices or protocols support this option. 1958.El 1959.Ss Sysctl Related Options 1960.Bl -ohang 1961.It Cd options SYSCTL_DISALLOW_CREATE 1962Disallows the creation or deletion of nodes from the sysctl tree, as 1963well as the assigning of descriptions to nodes that lack them, by any 1964process. 1965These operations are still available to kernel sub-systems, including 1966loadable kernel modules. 1967.It Cd options SYSCTL_DISALLOW_KWRITE 1968Prevents processes from adding nodes to the sysctl tree that make 1969existing kernel memory areas writable. 1970Sections of kernel memory can still be read and new nodes that own 1971their own data may still be writable. 1972.It Cd options SYSCTL_DEBUG_SETUP 1973Causes the SYSCTL_SETUP routines to print a brief message when they 1974are invoked. 1975This is merely meant as an aid in determining the order in which 1976sections of the tree are created. 1977.It Cd options SYSCTL_DEBUG_CREATE 1978Prints a message each time 1979.Fn sysctl_create , 1980the function that adds nodes to the tree, is called. 1981.It Cd options SYSCTL_INCLUDE_DESCR 1982Causes the kernel to include short, human readable descriptions for 1983nodes in the sysctl tree. 1984The descriptions can be retrieved programmatically (see 1985.Xr sysctl 3 ) , 1986or by the sysctl binary itself (see 1987.Xr sysctl 8 ) . 1988The descriptions are meant to give an indication of the purpose and/or 1989effects of a given node's value, not replace the documentation for the 1990given subsystem as a whole. 1991.El 1992.Ss System V IPC Options 1993.Bl -ohang 1994.It Cd options SYSVMSG 1995Includes support for 1996.At V 1997style message queues. 1998See 1999.Xr msgctl 2 , 2000.Xr msgget 2 , 2001.Xr msgrcv 2 , 2002.Xr msgsnd 2 . 2003.It Cd options SYSVSEM 2004Includes support for 2005.At V 2006style semaphores. 2007See 2008.Xr semctl 2 , 2009.Xr semget 2 , 2010.Xr semop 2 . 2011.It Cd options SEMMNI=value 2012Sets the number of 2013.At V 2014style semaphore identifiers. 2015The GENERIC config file for your port will have the default. 2016.It Cd options SEMMNS=value 2017Sets the number of 2018.At V 2019style semaphores in the system. 2020The GENERIC config file for your port will have the default. 2021.It Cd options SEMUME=value 2022Sets the maximum number of undo entries per process for 2023.At V 2024style semaphores. 2025The GENERIC config file for your port will have the default. 2026.It Cd options SEMMNU=value 2027Sets the number of undo structures in the system for 2028.At V 2029style semaphores. 2030The GENERIC config file for your port will have the default. 2031.It Cd options SYSVSHM 2032Includes support for 2033.At V 2034style shared memory. 2035See 2036.Xr shmat 2 , 2037.Xr shmctl 2 , 2038.Xr shmdt 2 , 2039.Xr shmget 2 . 2040.It Cd options SHMMAXPGS=value 2041Sets the maximum number of 2042.At V 2043style shared memory pages that are available through the 2044.Xr shmget 2 2045system call. 2046Default value is 1024 on most ports. 2047See 2048.Pa /usr/include/machine/vmparam.h 2049for the default. 2050.El 2051.Ss VM Related Options 2052.Bl -ohang 2053.It Cd options NMBCLUSTERS=value 2054The number of mbuf clusters the kernel supports. 2055Mbuf clusters are MCLBYTES in size (usually 2k). 2056This is used to compute the size of the kernel VM map 2057.Em mb_map , 2058which maps mbuf clusters. 2059Default on most ports is 1024 (2048 with 2060.Dq options GATEWAY 2061). 2062See 2063.Pa /usr/include/machine/param.h 2064for exact default information. 2065Increase this value if you get 2066.Dq mclpool limit reached 2067messages. 2068.It Cd options NKMEMPAGES=value 2069.It Cd options NKMEMPAGES_MIN=value 2070.It Cd options NKMEMPAGES_MAX=value 2071Size of kernel VM map 2072.Em kmem_map , 2073in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2074from the 2075.Xr sysctl 8 2076variable 2077.Em hw.pagesize 2078). 2079This VM map is used to map the kernel malloc arena. 2080The kernel attempts to auto-size this map based on the amount of 2081physical memory in the system. 2082Platform-specific code may place bounds on this computed size, 2083which may be viewed with the 2084.Xr sysctl 8 2085variable 2086.Em vm.nkmempages . 2087See 2088.Pa /usr/include/machine/param.h 2089for the default upper and lower bounds. 2090The related options 2091.Sq NKMEMPAGES_MIN 2092and 2093.Sq NKMEMPAGES_MAX 2094allow the bounds to be overridden in the kernel configuration file. 2095These options are provided in the event the computed value is 2096insufficient resulting in an 2097.Dq out of space in kmem_map 2098panic. 2099.It Cd options SB_MAX=value 2100Sets the max size in bytes that a socket buffer is allowed to occupy. 2101The default is 256k, but sometimes it needs to be increased, for example 2102when using large TCP windows. 2103This option can be changed via 2104.Xr sysctl 8 2105as well. 2106.It Cd options SOMAXKVA=value 2107Sets the maximum size of kernel virtual memory that the socket buffers 2108are allowed to use. 2109The default is 16MB, but in situations where for example large TCP 2110windows are used this value must also be increased. 2111This option can be changed via 2112.Xr sysctl 8 2113as well. 2114.It Cd options BUFCACHE=value 2115Size of the buffer cache as a percentage of total available 2116.Tn RAM . 2117Ignored if BUFPAGES is also specified. 2118.It Cd options NBUF=value 2119Sets the number of buffer headers available, i.e., the number of 2120open files that may have a buffer cache entry. 2121Each buffer header 2122requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2123The default value is machine dependent, but is usually equal to the 2124value of BUFPAGES. 2125If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2126then NBUF may be reduced at run time so that the storage allocated 2127for buffer headers doesn't exceed that limit. 2128.It Cd options BUFPAGES=value 2129These options set the number of pages available for the buffer cache. 2130Their default value is a machine dependent value, often calculated as 2131between 5% and 10% of total available 2132.Tn RAM . 2133.It Cd options MAXTSIZ=bytes 2134Sets the maximum size limit of a process' text segment. 2135See 2136.Pa /usr/include/machine/vmparam.h 2137for the port-specific default. 2138.It Cd options DFLDSIZ=bytes 2139Sets the default size limit of a process' data segment, the value that 2140will be returned as the soft limit for 2141.Dv RLIMIT_DATA 2142(as returned by 2143.Xr getrlimit 2 ) . 2144See 2145.Pa /usr/include/machine/vmparam.h 2146for the port-specific default. 2147.It Cd options MAXDSIZ=bytes 2148Sets the maximum size limit of a process' data segment, the value that 2149will be returned as the hard limit for 2150.Dv RLIMIT_DATA 2151(as returned by 2152.Xr getrlimit 2 ) . 2153See 2154.Pa /usr/include/machine/vmparam.h 2155for the port-specific default. 2156.It Cd options DFLSSIZ=bytes 2157Sets the default size limit of a process' stack segment, the value that 2158will be returned as the soft limit for 2159.Dv RLIMIT_STACK 2160(as returned by 2161.Xr getrlimit 2 ) . 2162See 2163.Pa /usr/include/machine/vmparam.h 2164for the port-specific default. 2165.It Cd options MAXSSIZ=bytes 2166Sets the maximum size limit of a process' stack segment, the value that 2167will be returned as the hard limit for 2168.Dv RLIMIT_STACK 2169(as returned by 2170.Xr getrlimit 2 ) . 2171See 2172.Pa /usr/include/machine/vmparam.h 2173for the port-specific default. 2174.It Cd options DUMP_ON_PANIC=integer 2175Defaults to one. 2176If set to zero, the kernel will not dump to the dump device when 2177it panics, though dumps can still be forced via 2178.Xr ddb 4 2179with the 2180.Dq sync 2181command. 2182Note that this sets the value of the 2183.Em kern.dump_on_panic 2184.Xr sysctl 3 2185variable which may be changed at run time -- see 2186.Xr sysctl 8 2187for details. 2188.It Cd options USE_TOPDOWN_VM 2189User space memory allocations (as made by 2190.Xr mmap 2 ) 2191will be arranged in a 2192.Dq top down 2193fashion instead of the traditional 2194.Dq upwards from MAXDSIZ \&+ vm_daddr 2195method. 2196This includes the placement of 2197.Xr ld.so 1 . 2198Arranging memory in this manner allows either (or both of) the heap or 2199.Xr mmap 2 2200allocated space to grow larger than traditionally possible. 2201This option is not available on all ports, but is instead expected to be 2202offered on a port-by-port basis, after which some ports will commit to 2203using it by default. 2204See the files 2205.Pa /usr/include/uvm/uvm_param.h 2206for some implementation details, and 2207.Pa /usr/include/machine/vmparam.h 2208for port specific details including availability. 2209.It Cd options VMSWAP 2210Enable paging device/file support. 2211This option is on by default. 2212.It Cd options PDPOLICY_CLOCKPRO 2213Use CLOCK-Pro, an alternative page replace policy. 2214.El 2215.Ss Security Options 2216.Bl -ohang 2217.It Cd options INSECURE 2218Hardwires the kernel security level at \-1. 2219This means that the system 2220always runs in secure level \-1 mode, even when running multiuser. 2221See the manual page for 2222.Xr init 8 2223for details on the implications of this. 2224The kernel secure level may manipulated by the superuser by altering the 2225.Em kern.securelevel 2226.Xr sysctl 3 2227variable (the secure level may only be lowered by a call from process ID 1, 2228i.e., 2229.Xr init 8 ) . 2230See also 2231.Xr secmodel_securelevel 9 , 2232.Xr sysctl 8 2233and 2234.Xr sysctl 3 . 2235.It Cd options VERIFIED_EXEC_FP_MD5 2236Enables support for MD5 hashes in Veriexec. 2237.It Cd options VERIFIED_EXEC_FP_SHA1 2238Enables support for SHA1 hashes in Veriexec. 2239.It Cd options VERIFIED_EXEC_FP_RMD160 2240Enables support for RMD160 hashes in Veriexec. 2241.It Cd options VERIFIED_EXEC_FP_SHA256 2242Enables support for SHA256 hashes in Veriexec. 2243.It Cd options VERIFIED_EXEC_FP_SHA384 2244Enables support for SHA384 hashes in Veriexec. 2245.It Cd options VERIFIED_EXEC_FP_SHA512 2246Enables support for SHA512 hashes in Veriexec. 2247.It Cd options PAX_MPROTECT=value 2248Enables PaX MPROTECT, 2249.Xr mprotect 2 2250restrictions from the PaX project. 2251.Pp 2252The 2253.Ar value 2254is the default value for the 2255.Em global 2256knob, see 2257.Xr sysctl 3 . 2258If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2259using 2260.Xr paxctl 8 . 2261If 1, PaX MPROTECT will be enabled for all programs. 2262Programs can be exempted using 2263.Xr paxctl 8 . 2264.Pp 2265See 2266.Xr security 7 2267for more details. 2268.It Cd options PAX_SEGVGUARD=value 2269Enables PaX Segvguard. 2270.Pp 2271The 2272.Ar value 2273is the default value for the 2274.Em global 2275knob, see 2276.Xr sysctl 3 . 2277If 0, PaX Segvguard will be enabled only if explicitly set on programs 2278using 2279.Xr paxctl 8 . 2280If 1, PaX Segvguard will be enabled to all programs, and exemption can 2281be done using 2282.Xr paxctl 8 . 2283.Pp 2284See 2285.Xr security 7 2286for more details. 2287.It Cd options PAX_ASLR=value 2288Enables PaX ASLR. 2289.Pp 2290The 2291.Ar value 2292is the default value for the 2293.Em global 2294knob, see 2295.Xr sysctl 3 . 2296If 0, PaX ASLR will be enabled only if explicitly set on programs 2297using 2298.Xr paxctl 8 . 2299If 1, PaX ASLR will be enabled to all programs, and exemption can 2300be done using 2301.Xr paxctl 8 . 2302.Pp 2303See 2304.Xr security 7 2305for more details. 2306.It Cd options USER_VA0_DISABLE_DEFAULT=value 2307Sets the initial value of the flag which controls whether user programs 2308can map virtual address 0. 2309The flag can be changed at runtime by 2310.Xr sysctl 3 . 2311.El 2312.Ss amiga-specific Options 2313.Bl -ohang 2314.It Cd options BB060STUPIDROM 2315When the bootloader (which passes 2316.Tn AmigaOS 2317.Tn ROM 2318information) claims we have a 68060 2319.Tn CPU 2320without 2321.Tn FPU , 2322go look into the Processor Configuration Register (PCR) to find out. 2323You need this with 2324.Tn Amiga 2325.Tn ROM Ns s 2326up to (at least) V40.xxx (OS3.1), 2327when you boot via the bootblocks and don't have a DraCo. 2328.It Cd options IOBZCLOCK=frequency 2329The IOBlix boards come with two different serial master clocks: older ones 2330use 24 MHz, newer ones use 22.1184 MHz. 2331The driver normally assumes the latter. 2332If your board uses 24 MHz, you can recompile your kernel with 2333options IOBZCLOCK=24000000 2334or patch the kernel variable 2335.Tn iobzclock 2336to the same value. 2337.It Cd options LIMITMEM=value 2338If there, limit the part of the first memory bank used by 2339.Nx 2340to value megabytes. 2341Default is unlimited. 2342.It Cd options NKPTADD=addvalue 2343.It Cd options NKPTADDSHIFT=shiftvalue 2344The 2345.Tn CPU 2346specific 2347.Tn MMU 2348table for the kernel is pre-allocated at kernel startup time. 2349Part of it is scaled with 2350.Va maxproc , 2351to have enough room to hold the user program 2352.Tn MMU 2353tables; the second part is a fixed amount for the kernel itself. 2354.Pp 2355The third part accounts for the size of the file buffer cache. 2356Its size is either 2357.Dv NKPTADD 2358pages (if defined) or memory size in bytes divided by two to 2359the power of 2360.Dv NKPTADDSHIFT . 2361The default is undefined 2362.Dv NKPTADD 2363and 2364.Dv NKPTADDSHIFT=24 , 2365allowing for 16 buffers per megabyte of main memory (while 2366a GENERIC kernel allocates about half of that). 2367When you get "can't get KPT page" panics, you should increase 2368.Dv NKPTADD 2369(if defined), or decrease 2370.Dv NKPTADDSHIFT 2371by one. 2372.It Cd options P5PPC68KBOARD 2373Add special support for Phase5 mixed 68k+PPC boards. 2374Currently, this only affects rebooting from 2375.Nx 2376and is only needed on 68040+PPC, not on 237768060+PPC; without this, affected machines will hang after 2378.Nx 2379has shut 2380down and will only restart after a keyboard reset or a power cycle. 2381.El 2382.Ss arm32-specific Options 2383.Bl -ohang 2384.It Cd options FRENCH_KBD 2385Include translation for French keyboards when using 2386.Em pccons 2387on a Shark. 2388.It Cd options FINNISH_KBD 2389Include translation for Finnish keyboards when using 2390.Em pccons 2391on a Shark. 2392.It Cd options GERMAN_KBD 2393Include translation for German keyboards when using 2394.Em pccons 2395on a Shark. 2396.It Cd options NORWEGIAN_KBD 2397Include translation for French keyboards when using 2398.Em pccons 2399on a Shark. 2400.El 2401.Ss atari-specific Options 2402.Bl -ohang 2403.It Cd options DISKLABEL_AHDI 2404Include support for AHDI (native Atari) disklabels. 2405.It Cd options DISKLABEL_NBDA 2406Include support for 2407.Nx Ns Tn /atari 2408labels. 2409If you don't set this option, it will be set automatically. 2410.Nx Ns Tn /atari 2411will not work without it. 2412.It Cd options FALCON_SCSI 2413Include support for the 5380-SCSI configuration as found on the Falcon. 2414.It Cd options RELOC_KERNEL 2415If set, the kernel will relocate itself to TT-RAM, if possible. 2416This will give you a slightly faster system. 2417.Em Beware 2418that on some TT030 systems, 2419the system will frequently dump with MMU-faults with this option enabled. 2420.It Cd options SERCONSOLE 2421Allow the modem1-port to act as the system-console. 2422A carrier should be active on modem1 during system boot to active 2423the console functionality. 2424.It Cd options TT_SCSI 2425Include support for the 5380-SCSI configuration as found on the TT030 2426and Hades. 2427.El 2428.Ss i386-specific Options 2429.Bl -ohang 2430.It Cd options CPURESET_DELAY=value 2431Specifies the time (in millisecond) to wait before doing a hardware reset 2432in the last phase of a reboot. 2433This gives the user a chance to see error messages from the shutdown 2434operations (like NFS unmounts, buffer cache flush, etc ...). 2435Setting this to 0 will disable the delay. 2436Default is 2 seconds. 2437.It Cd options VM86 2438Include support for virtual 8086 mode, used by 2439.Tn DOS 2440emulators and X servers to run BIOS code, e.g., for some VESA routines. 2441.It Cd options USER_LDT 2442Include i386-specific system calls for modifying the local descriptor table, 2443used by Windows emulators. 2444.It Cd options PAE 2445Enable 2446.Tn PAE (Physical Address Extension) 2447mode. 2448.Tn PAE 2449permits up to 36 bits physical addressing (64GB of physical memory), and 2450turns physical addresses to 64 bits entities in the memory management 2451subsystem. 2452Userland virtual address space remains at 32 bits (4GB). 2453.Tn PAE 2454mode is required to enable the 2455.Tn NX/XD (No-eXecute/eXecute Disable) 2456bit for pages, which allows marking certain ones as not being executable. 2457Any attempt to execute code from such a page will raise an exception. 2458.It Cd options REALBASEMEM=integer 2459Overrides the base memory size passed in from the boot block. 2460(Value given in kilobytes.) 2461Use this option only if the boot block reports the size incorrectly. 2462(Note that some 2463.Tn BIOS Ns es 2464put the extended 2465.Tn BIOS 2466data area at the top of base memory, and therefore report a smaller 2467base memory size to prevent programs overwriting it. 2468This is correct behavior, and you should not use the 2469.Em REALBASEMEM 2470option to access this memory). 2471.It Cd options REALEXTMEM=integer 2472Overrides the extended memory size passed in from the boot block. 2473(Value given in kilobytes. 2474Extended memory does not include the first megabyte.) 2475Use this option only if the boot block reports the size incorrectly. 2476.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2477Select a non-US keyboard layout for the 2478.Em pccons 2479console driver. 2480.It Cd options CYRIX_CACHE_WORKS 2481Relevant only to the Cyrix 486DLC CPU. 2482This option is used to turn on the cache in hold-flush mode. 2483It is not turned on by default because it is known to have problems in 2484certain motherboard implementations. 2485.It Cd options CYRIX_CACHE_REALLY_WORKS 2486Relevant only to the Cyrix 486DLC CPU. 2487This option is used to turn on the cache in write-back mode. 2488It is not turned on by default because it is known to have problems in 2489certain motherboard implementations. 2490In order for this option to take effect, option 2491.Em CYRIX_CACHE_WORKS 2492must also be specified. 2493.It Cd options PCIBIOS 2494Enable support for initializing the 2495.Tn PCI 2496bus using information from the 2497.Tn BIOS . 2498See 2499.Xr pcibios 4 2500for details. 2501.It Cd options KSTACK_CHECK_DR0 2502Detect kernel stack overflow using DR0 register. 2503This option uses DR0 register exclusively so you can't use DR0 register for 2504other purpose (e.g., hardware breakpoint) if you turn this on. 2505.It Cd options MTRR 2506Include support for accessing MTRR registers from user-space. 2507See 2508.Xr i386_get_mtrr 2 . 2509.It Cd options BEEP_ONHALT 2510Make the system speaker emit several beeps when it is completely safe to 2511power down the computer after a 2512.Xr halt 8 2513command. 2514Requires 2515.Xr sysbeep 4 2516support. 2517.It Cd options BEEP_ONHALT_COUNT=times 2518Number of times to beep the speaker when 2519.Cd options BEEP_ONHALT 2520is enabled. 2521Defaults to 3. 2522.It Cd options BEEP_ONHALT_PITCH=hz 2523The tone frequency used when 2524.Cd options BEEP_ONHALT 2525option, in hertz. 2526Defaults to 1500. 2527.It Cd options BEEP_ONHALT_PERIOD=msecs 2528The duration of each beep when 2529.Cd options BEEP_ONHALT 2530is enabled, in milliseconds. 2531Defaults to 250. 2532.It Cd options MULTIBOOT 2533Makes the kernel Multiboot-compliant, allowing it to be booted through 2534a Multiboot-compliant boot manager such as GRUB. 2535See 2536.Xr multiboot 8 2537for more information. 2538.It Cd options SPLASHSCREEN 2539Display a splash screen during boot. 2540.It Cd options SPLASHSCREEN_PROGRESS 2541Display a progress bar at the splash screen during boot. 2542This option requires 2543.Em SPLASHSCREEN . 2544.El 2545.Ss isa-specific Options 2546Options specific to 2547.Xr isa 4 2548busses. 2549.Bl -ohang 2550.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2551Control the section of IO bus space used for PCMCIA bus space mapping. 2552Ideally the probed defaults are satisfactory, however in practice 2553that is not always the case. 2554See 2555.Xr pcmcia 4 2556for details. 2557.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2558Controls the allowable interrupts that may be used for 2559.Tn PCMCIA 2560devices. 2561This mask is a logical-or of power-of-2s of allowable interrupts: 2562.Bd -literal -offset 04n 2563.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2564 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2565 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2566 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2567 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2568.Ed 2569.It Cd options PCKBC_CNATTACH_SELFTEST 2570Perform a self test of the keyboard controller before attaching it as a 2571console. 2572This might be necessary on machines where we boot on cold iron, and 2573pckbc refuses to talk until we request a self test. 2574Currently only the netwinder port uses it. 2575.It Cd options PCKBD_CNATTACH_MAY_FAIL 2576If this option is set the PS/2 keyboard will not be used as the console 2577if it cannot be found during boot. 2578This allows other keyboards, like USB, to be the console keyboard. 2579.It Cd options PCKBD_LAYOUT=layout 2580Sets the default keyboard layout, see 2581.Xr pckbd 4 . 2582.El 2583.Ss m68k-specific Options 2584.Bl -ohang 2585.It Cd options FPU_EMULATE 2586Include support for MC68881/MC68882 emulator. 2587.It Cd options FPSP 2588Include support for 68040 floating point. 2589.It Cd options M68020,M68030,M68040,M68060 2590Include support for a specific 2591.Tn CPU , 2592at least one (the one you are using) should be specified. 2593.It Cd options M060SP 2594Include software support for 68060. 2595This provides emulation of unimplemented 2596integer instructions as well as emulation of unimplemented floating point 2597instructions and data types and software support for floating point traps. 2598.El 2599.Ss powerpc-specific Options (OEA Only) 2600.Bl -ohang 2601.It Cd options PMAP_MEMLIMIT=value 2602Limit the amount of memory seen by the kernel to 2603.Ar value 2604bytes. 2605.It Cd options PTEGCOUNT=value 2606Specify the size of the page table as 2607.Ar value 2608PTE groups. 2609Normally, one PTEG is allocated per physical page frame. 2610.El 2611.Ss sparc-specific Options 2612.Bl -ohang 2613.It Cd options AUDIO_DEBUG 2614Enable simple event debugging of the logging of the 2615.Xr audio 4 2616device. 2617.It Cd options BLINK 2618Enable blinking of LED. 2619Blink rate is full cycle every N seconds for 2620N \*[Lt] then current load average. 2621See 2622.Xr getloadavg 3 . 2623.\" .It Cd options COLORFONT_CACHE 2624.\" What does this do? 2625.It Cd options COUNT_SW_LEFTOVERS 2626Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2627sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2628variables accessible from 2629.Xr ddb 4 . 2630See 2631.Xr sw 4 . 2632.It Cd options DEBUG_ALIGN 2633Adds debugging messages calls when user-requested alignment fault 2634handling happens. 2635.It Cd options DEBUG_EMUL 2636Adds debugging messages calls for emulated floating point and 2637alignment fixing operations. 2638.It Cd options DEBUG_SVR4 2639Prints registers messages calls for emulated SVR4 getcontext and 2640setcontext operations. 2641See 2642.Em options COMPAT_SVR4 . 2643.It Cd options EXTREME_DEBUG 2644Adds debugging functions callable from 2645.Xr ddb 4 . 2646The debug_pagetables, test_region and print_fe_map 2647functions print information about page tables for the SUN4M 2648platforms only. 2649.It Cd options EXTREME_EXTREME_DEBUG 2650Adds extra info to 2651.Em options EXTREME_DEBUG . 2652.It Cd options FPU_CONTEXT 2653Make 2654.Em options COMPAT_SVR4 2655getcontext and setcontext include floating point registers. 2656.It Cd options MAGMA_DEBUG 2657Adds debugging messages to the 2658.Xr magma 4 2659device. 2660.It Cd options RASTERCONS_FULLSCREEN 2661Use the entire screen for the console. 2662.It Cd options RASTERCONS_SMALLFONT 2663Use the Fixed font on the console, instead of the normal font. 2664.It Cd options SUN4 2665Support sun4 class machines. 2666.It Cd options SUN4C 2667Support sun4c class machines. 2668.It Cd options SUN4M 2669Support sun4m class machines. 2670.It Cd options SUN4_MMU3L 2671.\" XXX ??? 2672Enable support for sun4 3-level MMU machines. 2673.It Cd options V9 2674Enable SPARC V9 assembler in 2675.Xr ddb 4 . 2676.El 2677.Ss sparc64-specific Options 2678.Bl -ohang 2679.It Cd options AUDIO_DEBUG 2680Enable simple event debugging of the logging of the 2681.Xr audio 4 2682device. 2683.It Cd options BLINK 2684Enable blinking of LED. 2685Blink rate is full cycle every N seconds for 2686N \*[Lt] then current load average. 2687See 2688.Xr getloadavg 3 . 2689.El 2690.Ss x68k-specific Options 2691.Bl -ohang 2692.It Cd options EXTENDED_MEMORY 2693Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2694.It Cd options JUPITER 2695Include support for Jupiter-X MPU accelerator 2696.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2697Use the built-in serial port as the system-console. 2698Speed is specified in bps, defaults to 9600. 2699.It Cd options ITE_KERNEL_ATTR=value 2700Set the kernel message attribute for ITE. 2701Value, an integer, is a logical or of the following values: 2702.Bl -tag -width 4n -compact -offset indent 2703.It 1 2704color inversed 2705.It 2 2706underlined 2707.It 4 2708bolded 2709.El 2710.El 2711.\" The following requests should be uncommented and used where appropriate. 2712.\" .Sh FILES 2713.\" .Sh EXAMPLES 2714.Sh SEE ALSO 2715.Xr config 1 , 2716.Xr gdb 1 , 2717.Xr ktrace 1 , 2718.Xr pmc 1 , 2719.Xr quota 1 , 2720.Xr vndcompress 1 , 2721.Xr gettimeofday 2 , 2722.Xr i386_get_mtrr 2 , 2723.Xr i386_iopl 2 , 2724.Xr msgctl 2 , 2725.Xr msgget 2 , 2726.Xr msgrcv 2 , 2727.Xr msgsnd 2 , 2728.Xr ntp_adjtime 2 , 2729.Xr ntp_gettime 2 , 2730.Xr reboot 2 , 2731.Xr semctl 2 , 2732.Xr semget 2 , 2733.Xr semop 2 , 2734.Xr shmat 2 , 2735.Xr shmctl 2 , 2736.Xr shmdt 2 , 2737.Xr shmget 2 , 2738.Xr sysctl 3 , 2739.Xr apm 4 , 2740.Xr ddb 4 , 2741.Xr inet 4 , 2742.Xr iso 4 , 2743.Xr md 4 , 2744.Xr pcibios 4 , 2745.Xr pcmcia 4 , 2746.Xr ppp 4 , 2747.Xr userconf 4 , 2748.Xr vnd 4 , 2749.Xr wscons 4 , 2750.Xr config 5 , 2751.Xr edquota 8 , 2752.Xr init 8 , 2753.Xr mdsetimage 8 , 2754.Xr mount_cd9660 8 , 2755.Xr mount_fdesc 8 , 2756.Xr mount_kernfs 8 , 2757.Xr mount_lfs 8 , 2758.Xr mount_mfs 8 , 2759.Xr mount_msdos 8 , 2760.Xr mount_nfs 8 , 2761.Xr mount_ntfs 8 , 2762.Xr mount_null 8 , 2763.Xr mount_portal 8 , 2764.Xr mount_procfs 8 , 2765.Xr mount_udf 8 , 2766.Xr mount_umap 8 , 2767.Xr mount_union 8 , 2768.Xr mrouted 8 , 2769.Xr newfs_lfs 8 , 2770.Xr ntpd 8 , 2771.Xr quotaon 8 , 2772.Xr rpc.rquotad 8 , 2773.Xr sysctl 8 , 2774.Xr in_getifa 9 2775.Sh HISTORY 2776The 2777.Nm 2778man page first appeared in 2779.Nx 1.3 . 2780.Sh BUGS 2781The 2782.Em EON 2783option should be a pseudo-device, and is also very fragile. 2784