1.\" $NetBSD: options.4,v 1.382 2009/12/05 20:11:02 pooka 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 17, 2009 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_DARWIN 398On those architectures that support it, this enables binary compatibility with 399.Tn Darwin 400applications built for the same architecture. 401This feature is highly experimental, it requires COMPAT_MACH and 402EXEC_MACHO and it is currently limited to i386 and powerpc ports of 403.Nx . 404.It Cd options COMPAT_FREEBSD 405On those architectures that support it, this enables binary 406compatibility with 407.Fx 408applications built for the same architecture. 409At the moment this is limited to the i386 port. 410.It Cd options COMPAT_IBCS2 411On those architectures that support it, this enables binary 412compatibility with iBCS2 or SVR3 applications built for the same architecture. 413This is currently limited to the i386 and vax ports. 414.It Cd options COMPAT_IRIX 415On those architectures that support it, this enables binary 416compatibility with IRIX o32 binaries built for the same architecture. 417This feature is experimental, and it is currently limited to 418the sgimips port. 419.It Cd options COMPAT_MACH 420On those architectures that support it, this enables the emulation of 421Mach kernel traps for binaries built for the same architecture. 422This feature is highly experimental and it is currently 423limited to the i386 and powerpc ports of 424.Nx . 425.It Cd options COMPAT_OSF1 426On those architectures that support it, this enables binary 427compatibility with 428.Tn Digital 429.Ux 430.Po 431formerly 432.Tn OSF/1 433.Pc 434applications built for the same architecture. 435This is currently limited to the alpha port. 436.It Cd options COMPAT_NOMID 437Enable compatibility with 438.Xr a.out 5 439executables that lack a machine ID. 440This includes 441.Nx 0.8 Ns 's 442ZMAGIC format, and 386BSD and BSDI's 443QMAGIC, NMAGIC, and OMAGIC 444.Xr a.out 5 445formats. 446.It Cd options COMPAT_NETBSD32 447On those architectures that support it, this enables binary 448compatibility with 32-bit applications built for the same architecture. 449This is currently limited to the amd64 and sparc64 ports, and only 450applicable for 64-bit kernels. 451.It Cd options COMPAT_SVR4_32 452On those architectures that support it, this enables binary 453compatibility with 32-bit SVR4 applications built for the same architecture. 454This is currently limited to the sparc64 port, and only applicable for 45564-bit kernels. 456.It Cd options COMPAT_AOUT_M68K 457On m68k architectures which have switched to ELF, 458this enables binary compatibility with 459.Nx Ns Tn /m68k 460.Xr a.out 5 461executables on 462.Nx Ns Tn /m68k 463ELF kernels. 464This handles alignment incompatibility of m68k ABI between 465a.out and ELF which causes the structure padding differences. 466Currently only some system calls which use 467.Va struct stat 468are adjusted and some binaries which use 469.Xr sysctl 3 470to retrieve network details would not work properly. 471.It Cd options EXEC_MACHO 472On those architectures that support it, this adds support for running 473Mach-O executables. 474This is currently limited to the i386 and powerpc ports of 475.Nx . 476.It Cd options EXEC_ELF_NOTELESS 477Run unidentified ELF binaries as 478.Nx 479binaries. 480This might be needed for very old 481.Nx 482ELF binaries on some archs. 483These old binaries didn't contain an appropriate 484.Li .note.netbsd.ident 485section, and thus can't be identified by the kernel as 486.Nx 487binaries otherwise. 488Beware - if this option is on, the kernel would run 489.Em any 490unknown ELF binaries as if they were 491.Nx 492binaries. 493.It Cd options P1003_1B_SEMAPHORE 494Includes kernel support for the standard C library 495.Pq libc 496functions that implement semaphores as specified in 497.St -p1003.1-96 . 498.El 499.Ss Debugging Options 500.Bl -ohang 501.It Cd options DDB 502Compiles in a kernel debugger for diagnosing kernel problems. 503See 504.Xr ddb 4 505for details. 506.Em NOTE : 507not available on all architectures. 508.It Cd options DDB_FROMCONSOLE=integer 509If set to non-zero, DDB may be entered by sending a break on a serial 510console or by a special key sequence on a graphics console. 511A value of "0" ignores console breaks or key sequences. 512If not explicitly specified, the default value is "1". 513Note that this sets the value of the 514.Em ddb.fromconsole 515.Xr sysctl 3 516variable which may be changed at run time -- see 517.Xr sysctl 8 518for details. 519.It Cd options DDB_HISTORY_SIZE=integer 520If this is non-zero, enable history editing in the kernel debugger 521and set the size of the history to this value. 522.It Cd options DDB_ONPANIC 523The default if not specified is 524.Dq 1 525- just enter into DDB. 526If set to 527.Dq 2 528the kernel will 529attempt to print out a stack trace before entering into DDB. 530If set to 531.Dq 0 532the kernel will attempt to print out a stack trace 533and reboot the system. 534If set to 535.Dq -1 536then neither a stack trace is printed or DDB entered - 537it is as if DDB were not compiled into the kernel. 538Note that this sets the value of the 539.Em ddb.onpanic 540.Xr sysctl 3 541variable which may be changed at run time -- see 542.Xr sysctl 8 543for details. 544.It Cd options DDB_COMMANDONENTER=string 545This option specify commands which will be executed on each entry to DDB. 546This sets the default value of the 547.Em ddb.commandonenter 548.Xr sysctl 3 549variable which may be changed at run time. 550.It Cd options DDB_BREAK_CHAR=integer 551This option overrides using break to enter the kernel debugger 552on the serial console. 553The value given is the ASCII value to be used instead. 554This is currently only supported by the com driver. 555.It Cd options DDB_VERBOSE_HELP 556This option adds more verbose descriptions to the 557.Em help 558command. 559.It Cd options KGDB 560Compiles in a remote kernel debugger stub for diagnosing kernel problems 561using the 562.Dq remote target 563feature of gdb. 564See 565.Xr gdb 1 566for details. 567.Em NOTE : 568not available on all architectures. 569.It Cd options KGDB_DEV 570Device number 571.Po 572as a 573.Dv dev_t 574.Pc 575of kgdb device. 576.It Cd options KGDB_DEVADDR 577Memory address of kgdb device. 578.It Cd options KGDB_DEVMODE 579Permissions of kgdb device. 580.It Cd options KGDB_DEVNAME 581Device name of kgdb device. 582.It Cd options KGDB_DEVRATE 583Baud rate of kgdb device. 584.It Cd makeoptions DEBUG="-g" 585The 586.Fl g 587flag causes 588.Pa netbsd.gdb 589to be built in addition to 590.Pa netbsd . 591.Pa netbsd.gdb 592is useful for debugging kernel crash dumps with gdb. 593See 594.Xr gdb 1 595for details. 596This also turns on 597.Em options DEBUG 598(which see). 599.It Cd options DEBUG 600Turns on miscellaneous kernel debugging. 601Since options are turned into preprocessor defines (see above), 602.Em options DEBUG 603is equivalent to doing a 604.Em #define DEBUG 605throughout the kernel. 606Much of the kernel has 607.Em #ifdef DEBUG 608conditionalized debugging code. 609Note that many parts of the kernel (typically device drivers) include their own 610.Em #ifdef XXX_DEBUG 611conditionals instead. 612This option also turns on certain other options, 613which may decrease system performance. 614.It Cd options DIAGNOSTIC 615Adds code to the kernel that does internal consistency checks. 616This code will cause the kernel to panic if corruption of internal data 617structures is detected. 618These checks can decrease performance up to 15%. 619.It Cd options LOCKDEBUG 620Adds code to the kernel to detect incorrect use of locking primitives 621(mutex, rwlock, simplelock). 622This code will cause the kernel to check for dead lock conditions. 623It will also check for memory being freed to not contain initialised 624lock primitives. 625Functions for use in 626.Xr ddb 4 627to check lock chains etc. are also enabled. 628These checks are very expensive and can decrease performance on 629multi-processor machines by a factor of three. 630.It Cd options KSTACK_CHECK_MAGIC 631Check kernel stack usage and panic if stack overflow is detected. 632This check is performance sensitive because it scans stack on each context 633switch. 634.It Cd options KTRACE 635Add hooks for the system call tracing facility, which allows users to 636watch the system call invocation behavior of processes. 637See 638.Xr ktrace 1 639for details. 640.It Cd options MSGBUFSIZE=integer 641This option sets the size of the kernel message buffer. 642This buffer holds the kernel output of 643.Fn printf 644when not (yet) read by 645.Xr syslogd 8 . 646This is particularly useful when the system has crashed and you wish to lookup 647the kernel output from just before the crash. 648Also, since the autoconfig output becomes more and more verbose, 649it sometimes happens that the message buffer overflows before 650.Xr syslogd 8 651was able to read it. 652Note that not all systems are capable of obtaining a variable sized message 653buffer. 654There are also some systems on which memory contents are not preserved 655across reboots. 656.It Cd options MALLOCLOG 657Enables an event log for 658.Xr malloc 9 . 659Useful for tracking down 660.Dq Data modified on freelist 661and 662.Dq multiple free 663problems. 664.It Cd options MALLOCLOGSIZE=integer 665Defines the number of entries in the malloc log. 666Default is 100000 entries. 667.It Cd options UVMHIST 668Enables the UVM history logs, which create in-memory traces of 669various UVM activities. 670These logs can be displayed be calling 671.Fn uvmhist_dump 672or 673.Fn uvm_hist 674with appropriate arguments from DDB. 675See the kernel source file sys/uvm/uvm_stat.c for details. 676.It Cd options UVMHIST_PRINT 677Prints the UVM history logs on the system console as entries are added. 678Note that the output is 679.Em extremely 680voluminous, so this option is really only useful for debugging 681the very earliest parts of kernel initialization. 682.El 683.Ss File Systems 684.Bl -ohang 685.It Cd file-system FFS 686Includes code implementing the Berkeley Fast File System 687.Po Em FFS Pc . 688Most machines need this if they are not running diskless. 689.It Cd file-system EXT2FS 690Includes code implementing the Second Extended File System 691.Po Em EXT2FS Pc , 692revision 0 and revision 1 with the 693.Em filetype 694and 695.Em sparse_super 696options. 697This is the most commonly used file system on the Linux operating system, 698and is provided here for compatibility. 699Some of the specific features of 700.Em EXT2FS 701like the "behavior on errors" are not implemented. 702This file system can't be used with UID or GID greater than 65535. 703See 704.Xr mount_ext2fs 8 705for details. 706.It Cd file-system LFS 707.Bq Em EXPERIMENTAL 708Include the Log-structured File System 709.Po Em LFS Pc . 710See 711.Xr mount_lfs 8 712and 713.Xr newfs_lfs 8 714for details. 715.It Cd file-system MFS 716Include the Memory File System 717.Po Em MFS Pc . 718This file system stores files in swappable memory, and produces 719notable performance improvements when it is used as the file store 720for 721.Pa /tmp 722and similar file systems. 723See 724.Xr mount_mfs 8 725for details. 726.It Cd file-system NFS 727Include the client side of the Network File System 728.Pq Tn NFS 729remote file sharing protocol. 730Although the bulk of the code implementing 731.Tn NFS 732is kernel based, several user level daemons are needed for it to work. 733See 734.Xr mount_nfs 8 735for details. 736.It Cd file-system CD9660 737Includes code for the 738.Tn ISO 7399660 + Rock Ridge file system, which is the standard file system on many 740.Tn CD-ROM 741discs. 742Useful primarily if you have a 743.Tn CD-ROM 744drive. 745See 746.Xr mount_cd9660 8 747for details. 748.It Cd file-system MSDOSFS 749Includes the 750.Tn MS-DOS 751FAT file system, which is reportedly still used 752by unfortunate people who have not heard about 753.Nx . 754Also implements the 755.Tn Windows 95 756extensions to the same, which permit the use of longer, mixed case 757file names. 758See 759.Xr mount_msdos 8 760and 761.Xr fsck_msdos 8 762for details. 763.It Cd file-system NTFS 764.Bq Em EXPERIMENTAL 765Includes code for the 766.Tn Microsoft Windows NT 767file system. 768See 769.Xr mount_ntfs 8 770for details. 771.It Cd file-system FDESC 772Includes code for a file system, conventionally mounted on 773.Pa /dev/fd , 774which permits access to the per-process file descriptor space via 775special files in the file system. 776See 777.Xr mount_fdesc 8 778for details. 779Note that this facility is redundant, and thus unneeded on most 780.Nx 781systems, since the 782.Xr fd 4 783pseudo-device driver already provides identical functionality. 784On most 785.Nx 786systems, instances of 787.Xr fd 4 788are mknoded under 789.Pa /dev/fd/ 790and on 791.Pa /dev/stdin , 792.Pa /dev/stdout , 793and 794.Pa /dev/stderr . 795.It Cd file-system KERNFS 796Includes code which permits the mounting of a special file system 797(normally mounted on 798.Pa /kern ) 799in which files representing various kernel variables and parameters 800may be found. 801See 802.Xr mount_kernfs 8 803for details. 804.It Cd file-system NULLFS 805Includes code for a loopback file system. 806This permits portions of the file hierarchy to be re-mounted in other places. 807The code really exists to provide an example of a stackable file system layer. 808See 809.Xr mount_null 8 810for details. 811.It Cd file-system OVERLAY 812Includes code for a file system filter. 813This permits the overlay file system to intercept all access to an underlying 814file system. 815This file system is intended to serve as an example of a stacking file 816system which has a need to interpose itself between an underlying file 817system and all other access. 818See 819.Xr mount_overlay 8 820for details. 821.It Cd file-system PROCFS 822Includes code for a special file system (conventionally mounted on 823.Pa /proc ) 824in which the process space becomes visible in the file system. 825Among 826other things, the memory spaces of processes running on the system are 827visible as files, and signals may be sent to processes by writing to 828.Pa ctl 829files in the procfs namespace. 830See 831.Xr mount_procfs 8 832for details. 833.It Cd file-system UDF 834.Bq Em EXPERIMENTAL 835Includes code for the UDF file system commonly found on CD and DVD 836media but also more and more on USB sticks. 837Useful primarily if you have a CD or a DVD drive, be it a read-only 838or a rewritable device. 839Currently only supports read-access. 840See 841.Xr mount_udf 8 842for details. 843.It Cd file-system UMAPFS 844Includes a loopback file system in which user and group IDs may be 845remapped -- this can be useful when mounting alien file systems with 846different UIDs and GIDs than the local system. 847See 848.Xr mount_umap 8 849for details. 850.It Cd file-system UNION 851.Bq Em EXPERIMENTAL 852Includes code for the union file system, which permits directories to 853be mounted on top of each other in such a way that both file systems 854remain visible -- this permits tricks like allowing writing (and the 855deleting of files) on a read-only file system like a 856.Tn CD-ROM 857by mounting a local writable file system on top of the read-only file system. 858See 859.Xr mount_union 8 860for details. 861.It Cd file-system CODA 862.Bq Em EXPERIMENTAL 863Includes code for the Coda file system. 864Coda is a distributed file system like NFS and AFS. 865It is freely available, like NFS, but it functions much like AFS in being a 866.Dq stateful 867file system. 868Both Coda and AFS cache files on your local machine to improve performance. 869Then Coda goes a step further than AFS by letting you access the cached 870files when there is no available network, viz. disconnected laptops and 871network outages. 872In Coda, both the client and server are outside the kernel which makes 873them easier to experiment with. 874Coda is available for several UNIX and non-UNIX platforms. 875See http://www.coda.cs.cmu.edu for more details. 876.Em NOTE : 877You also need to enable the pseudo-device, vcoda, for the Coda 878file system to work. 879.It Cd file-system SMBFS 880.Bq Em EXPERIMENTAL 881Includes code for the SMB/CIFS file system. 882See 883.Xr mount_smbfs 8 884for details. 885.Em NOTE : 886You also need to enable the pseudo-device, nsmb, for the SMB 887file system to work. 888.It Cd file-system PTYFS 889.Bq Em EXPERIMENTAL 890Includes code for a special file system (normally mounted on 891.Pa /dev/pts ) 892in which pseudo-terminal slave devices become visible in the file system. 893See 894.Xr mount_ptyfs 8 895for details. 896.It Cd file-system TMPFS 897Includes code for the efficient memory file system, normally used over 898.Pa /tmp . 899See 900.Xr mount_tmpfs 8 901for details. 902.It Cd file-system PUFFS 903.Bq Em EXPERIMENTAL 904Includes kernel support for the pass-to-userspace framework file system. 905It can be used to implement file system functionality in userspace. 906See 907.Xr puffs 3 908and 909.Xr puffs 4 910for more details. 911This option is required for sshfs: 912.Xr mount_psshfs 8 . 913.El 914.Ss File System Options 915.Bl -ohang 916.It Cd options MAGICLINKS 917Enables the expansion of special strings 918.Po 919beginning with 920.Dq @ 921.Pc 922when traversing symbolic links. 923See 924.Xr symlink 7 925for a list of supported strings. 926Note that this option only controls the enabling of this feature 927by the kernel at boot-up. 928This feature can still be manipulated with the 929.Xr sysctl 8 930command regardless of the setting of this option. 931.It Cd options NFSSERVER 932Include the server side of the 933.Em NFS 934(Network File System) remote file sharing protocol. 935Although the bulk of the code implementing 936.Em NFS 937is kernel based, several user level daemons are needed for it to 938work. 939See 940.Xr mountd 8 941and 942.Xr nfsd 8 943for details. 944.It Cd options QUOTA 945Enables kernel support for file system quotas. 946See 947.Xr quotaon 8 , 948.Xr edquota 8 , 949and 950.Xr quota 1 951for details. 952Note that quotas only work on 953.Dq ffs 954file systems, although 955.Xr rpc.rquotad 8 956permits them to be accessed over 957.Em NFS . 958.It Cd options FFS_EI 959Enable ``Endian-Independent'' FFS support. 960This allows a system to mount an FFS file system created for another 961architecture, at a small performance cost for all FFS file systems. 962See also 963.Xr newfs 8 , 964.Xr fsck_ffs 8 , 965.Xr dumpfs 8 966for file system byte order status and manipulation. 967.It Cd options FFS_NO_SNAPSHOT 968Disable the 969.Dq file system snapshot 970support in FFS file systems. 971Maybe useful for install media kernels, small memory systems and 972embedded systems which don't require the snapshot support. 973.It Cd options WAPBL 974Enable 975.Dq Write Ahead Physical Block Logging file system journaling . 976This provides rapid file system consistency checking after a system outage. 977It also provides better general use performance over regular FFS. 978See also 979.Xr wapbl 4 . 980.It Cd options NVNODE=integer 981This option sets the size of the cache used by the name-to-inode translation 982routines, (a.k.a. the 983.Fn namei 984cache, though called by many other names in the kernel source). 985By default, this cache has 986.Dv NPROC 987(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 988A reasonable way to derive a value of 989.Dv NVNODE , 990should you notice a large number of namei cache misses with a tool such as 991.Xr systat 1 , 992is to examine your system's current computed value with 993.Xr sysctl 8 , 994(which calls this parameter "kern.maxvnodes") and to increase this value 995until either the namei cache hit rate improves or it is determined that 996your system does not benefit substantially from an increase in the size of 997the namei cache. 998.It Cd options NAMECACHE_ENTER_REVERSE 999Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1000as well as a normal one. 1001Normally, this is already done for directory vnodes, to speed up the getcwd 1002operation. 1003This option will cause longer hash chains in the reverse cache, and thus 1004slow down getcwd somewhat. 1005However, it does make vnode -\*[Gt] path translations possible in some cases. 1006For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1007required. 1008.It Cd options EXT2FS_SYSTEM_FLAGS 1009This option changes the behavior of the APPEND and IMMUTABLE flags 1010for a file on an 1011.Em EXT2FS 1012file system. 1013Without this option, the superuser or owner of the file can 1014set and clear them. 1015With this option, only the superuser can set them, and 1016they can't be cleared if the securelevel is greater than 0. 1017See also 1018.Xr chflags 1 1019and 1020.Xr secmodel_securelevel 9 . 1021.It Cd options NFS_BOOT_BOOTP 1022Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1023information if NFS is used to mount the root file system. 1024See 1025.Xr diskless 8 1026for details. 1027.It Cd options NFS_BOOT_DHCP 1028Same as 1029.Dq NFS_BOOT_BOOTP , 1030but use the DHCP extensions to the 1031BOOTP protocol (RFC 1541). 1032.It Cd options NFS_BOOT_BOOTP_REQFILE 1033Specifies the string sent in the bp_file field of the BOOTP / DHCP 1034request packet. 1035.It Cd options NFS_BOOT_BOOTPARAM 1036Enable use of the BOOTPARAM protocol, consisting of RARP and 1037BOOTPARAM RPC, to get configuration information if NFS 1038is used to mount the root file system. 1039See 1040.Xr diskless 8 1041for details. 1042.It Cd options NFS_BOOT_RWSIZE=value 1043Set the initial NFS read and write sizes for diskless-boot requests. 1044The normal default is 8Kbytes. 1045This option provides a way to lower the value (e.g., to 1024 bytes) 1046as a workaround for buggy network interface cards or boot PROMs. 1047Once booted, the read and write request sizes can be increased by 1048remounting the file system. 1049See 1050.Xr mount_nfs 8 1051for details. 1052.It Cd options NFS_V2_ONLY 1053Reduce the size of the NFS client code by omitting code that's only required 1054for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1055servers. 1056.It Cd options UFS_DIRHASH 1057Increase lookup performance by maintaining in-core hash tables 1058for large directories. 1059.El 1060.Ss Buffer queue strategy options 1061The following options enable alternative buffer queue strategies. 1062.Bl -ohang 1063.It Cd options BUFQ_READPRIO 1064Enable experimental buffer queue strategy for disk I/O. 1065In the default strategy, outstanding disk requests are ordered by 1066sector number and sent to the disk, regardless of whether the 1067operation is a read or write; this option gives priority to issuing 1068read requests over write requests. 1069Although requests may therefore be issued out of sector-order, causing 1070more seeks and thus lower overall throughput, interactive system 1071responsiveness under heavy disk I/O load may be improved, as processes 1072blocking on disk reads are serviced sooner (file writes typically 1073don't cause applications to block). 1074The performance effect varies greatly depending on the hardware, drive 1075firmware, file system configuration, workload, and desired performance 1076trade-off. 1077Systems using drive write-cache (most modern IDE disks, by default) 1078are unlikely to benefit and may well suffer; such disks acknowledge 1079writes very quickly, and optimize them internally according to 1080physical layout. 1081Giving these disks as many requests to work with as possible (the 1082standard strategy) will typically produce the best results, especially 1083if the drive has a large cache; the drive will silently complete 1084writes from cache as it seeks for reads. 1085Disks that support a large number of concurrent tagged requests (SCSI 1086disks and many hardware RAID controllers) expose this internal 1087scheduling with tagged responses, and don't block for reads; such 1088disks may not see a noticeable difference with either strategy. 1089However, if IDE disks are run with write-cache disabled for safety, 1090writes are not acknowledged until actually completed, and only one 1091request can be outstanding; a large number of small writes in one 1092locality can keep the disk busy, starving reads elsewhere on the disk. 1093Such systems are likely to see the most benefit from this option. 1094Finally, the performance interaction of this option with ffs soft 1095dependencies can be subtle, as that mechanism can drastically alter 1096the workload for file system metadata writes. 1097.It Cd options BUFQ_PRIOCSCAN 1098Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1099.It Cd options NEW_BUFQ_STRATEGY 1100Synonym of 1101.Em BUFQ_READPRIO . 1102.El 1103.Ss Miscellaneous Options 1104.Bl -ohang 1105.It Cd options MEMORY_DISK_DYNAMIC 1106This option makes the 1107.Xr md 4 1108.Tn RAM 1109disk size dynamically sized. 1110It is incompatible with 1111.Xr mdsetimage 8 . 1112.It Cd options MEMORY_DISK_HOOKS 1113This option allows for some machine dependent functions to be called when 1114the 1115.Xr md 4 1116.Tn RAM 1117disk driver is configured. 1118This can result in automatically loading a 1119.Tn RAM 1120disk from floppy on open (among other things). 1121.It Cd options MEMORY_DISK_IS_ROOT 1122Forces the 1123.Xr md 4 1124.Tn RAM 1125disk to be the root device. 1126This can only be overridden when 1127the kernel is booted in the 'ask-for-root' mode. 1128.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1129Allocates the given number of 512 byte blocks as memory for the 1130.Xr md 4 1131.Tn RAM 1132disk, to be populated with 1133.Xr mdsetimage 8 . 1134.It Cd options MEMORY_DISK_SERVER=0 1135Do not include the interface to a userland memory disk server process. 1136Per default, this option is set to 1, including the support code. 1137Useful for install media kernels. 1138.It Cd options MEMORY_DISK_RBFLAGS=value 1139This option sets the 1140.Xr reboot 2 1141flags used when booting with a memory disk as root file system. 1142Possible values include 1143.Dv RB_AUTOBOOT 1144(boot in the usual fashion - default value), and 1145.Dv RB_SINGLE 1146(boot in single-user mode). 1147.It Cd options MODULAR 1148Enables the framework for kernel modules. 1149.It Cd options VND_COMPRESSION 1150Enables the 1151.Xr vnd 4 1152driver to also handle compressed images. 1153See 1154.Xr vndcompress 1 , 1155.Xr vnd 4 1156and 1157.Xr vnconfig 8 1158for more information. 1159.It Cd options SPLDEBUG 1160Help the kernel programmer find bugs related to the interrupt priority 1161level. 1162When 1163.Fn spllower 1164or 1165.Fn splraise 1166changes the current CPU's interrupt priority level to or from 1167.Dv IPL_HIGH , 1168record a backtrace. 1169Read 1170.Xr return_address 9 1171for caveats about collecting backtraces. 1172This feature is experimental, and it is only available on i386. 1173See 1174.Pa sys/kern/subr_spldebug.c . 1175.It Cd options TFTPROOT 1176Download the root memory disk through TFTP at root mount time. 1177This enables the use of a root 1178.Tn RAM 1179disk without requiring it to be embedded in the kernel using 1180.Xr mdsetimage 8 . 1181The 1182.Tn RAM 1183disk name is obtained using DHCP's filename parameter. 1184This option requires 1185.Em MEMORY_DISK_HOOKS , 1186.Em MEMORY_DISK_DYNAMIC , 1187and 1188.Em MEMORY_DISK_IS_ROOT . 1189It is incompatible with 1190.Em MEMORY_DISK_ROOT_SIZE . 1191.It Cd options MALLOC_NOINLINE 1192Time critical fixed size memory allocation is performed with 1193.Fn MALLOC 1194and 1195.Fn FREE . 1196Normally these expand to inline code, but with 1197.Em MALLOC_NOINLINE 1198these call the normal 1199.Fn malloc 1200and 1201.Fn free 1202functions. 1203Useful for install media kernels, small memory systems and embedded systems. 1204.It Cd options HZ=integer 1205On ports that support it, set the system clock frequency (see 1206.Xr hz 9 ) 1207to the supplied value. 1208Handle with care. 1209.It Cd options NTP 1210Turns on in-kernel precision timekeeping support used by software 1211implementing 1212.Em NTP 1213(Network Time Protocol, RFC 1305). 1214The 1215.Em NTP 1216option adds an in-kernel Phase-Locked Loop (PLL) for normal 1217.Em NTP 1218operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1219operation. 1220.Xr ntpd 8 1221will employ a user-level PLL when kernel support is unavailable, 1222but the in-kernel version has lower latency and more precision, and 1223so typically keeps much better time. 1224The interface to the kernel 1225.Em NTP 1226support is provided by the 1227.Xr ntp_adjtime 2 1228and 1229.Xr ntp_gettime 2 1230system calls, which are intended for use by 1231.Xr ntpd 8 1232and are enabled by the option. 1233On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1234is not an integer, the 1235.Em NTP 1236option also enables extended-precision arithmetic to keep track of 1237fractional clock ticks at NTP time-format precision. 1238.It Cd options PPS_SYNC 1239This option enables a kernel serial line discipline for receiving time 1240phase signals from an external reference clock such as a radio clock. 1241(The 1242.Em NTP 1243option (which see) must be on if the 1244.Em PPS_SYNC 1245option is used.) 1246Some reference clocks generate a Pulse Per Second (PPS) signal in 1247phase with their time source. 1248The 1249.Em PPS 1250line discipline receives this signal on either the data leads 1251or the DCD control lead of a serial port. 1252.Em NTP 1253uses the PPS signal to discipline the local clock oscillator to a high 1254degree of precision (typically less than 50 microseconds in time and 12550.1 ppm in accuracy). 1256.Em PPS 1257can also generate a serial output pulse when the system receives a PPS 1258interrupt. 1259This can be used to measure the system interrupt latency and thus calibrate 1260.Em NTP 1261to account for it. 1262Using 1263.Em PPS 1264usually requires a 1265gadget box 1266to convert from TTL to RS-232 signal levels. 1267The gadget box and PPS are described in more detail in the HTML documentation 1268for 1269.Xr ntpd 8 1270in 1271.Pa /usr/share/doc/html/ntp . 1272.It Cd options SETUIDSCRIPTS 1273Allows scripts with the setuid bit set to execute as the effective 1274user rather than the real user, just like binary executables. 1275.Pp 1276.Em NOTE : 1277Using this option will also enable 1278.Em options FDSCRIPTS 1279.It Cd options FDSCRIPTS 1280Allows execution of scripts with the execute bit set, but not the 1281read bit, by opening the file and passing the file descriptor to 1282the shell, rather than the filename. 1283.Pp 1284.Em NOTE : 1285Execute only (non-readable) scripts will have 1286.Va argv[0] 1287set to 1288.Pa /dev/fd/* . 1289What this option allows as far as security is 1290concerned, is the ability to safely ensure that the correct script 1291is run by the interpreter, as it is passed as an already open file. 1292.It Cd options PUCCN 1293Enables treating serial ports found on PCI boards 1294.Xr puc 4 1295as potential console devices. 1296The method for choosing such a console device is port dependent. 1297.It Cd options RTC_OFFSET=integer 1298The kernel (and typically the hardware battery backed-up clock on 1299those machines that have one) keeps time in 1300.Em UTC 1301(Universal Coordinated Time, once known as 1302.Em GMT , 1303or Greenwich Mean Time) 1304and not in the time of the local time zone. 1305The 1306.Em RTC_OFFSET 1307option is used on some ports (such as the i386) to tell the kernel 1308that the hardware clock is offset from 1309.Em UTC 1310by the specified number of minutes. 1311This is typically used when a machine boots several operating 1312systems and one of them wants the hardware clock to run in the 1313local time zone and not in 1314.Em UTC , 1315e.g. 1316.Em RTC_OFFSET=300 1317means 1318the hardware clock is set to US Eastern Time (300 minutes behind 1319.Em UTC ) , 1320and not 1321.Em UTC . 1322(Note: 1323.Em RTC_OFFSET 1324is used to initialize a kernel variable named 1325.Va rtc_offset 1326which is the source actually used to determine the clock offset, and 1327which may be accessed via the kern.rtc_offset sysctl variable. 1328See 1329.Xr sysctl 8 1330and 1331.Xr sysctl 3 1332for details. 1333Since the kernel clock is initialized from the hardware clock very 1334early in the boot process, it is not possible to meaningfully change 1335.Va rtc_offset 1336in system initialization scripts. 1337Changing this value currently may only be done at kernel compile 1338time or by patching the kernel and rebooting). 1339.Pp 1340.Em NOTE : 1341Unfortunately, in many cases where the hardware clock 1342is kept in local time, it is adjusted for Daylight Savings 1343Time; this means that attempting to use 1344.Em RTC_OFFSET 1345to let 1346.Nx 1347coexist with such an operating system, like Windows, 1348would necessitate changing 1349.Em RTC_OFFSET 1350twice a year. 1351As such, this solution is imperfect. 1352.It Cd options KMEMSTATS 1353The kernel memory allocator, 1354.Xr malloc 9 , 1355will keep statistics on its performance if this option is enabled. 1356Unfortunately, this option therefore essentially disables the 1357.Fn MALLOC 1358and 1359.Fn FREE 1360forms of the memory allocator, which are used to enhance the performance 1361of certain critical sections of code in the kernel. 1362This option therefore can lead to a significant decrease in the 1363performance of certain code in the kernel if enabled. 1364Examples of such code include the 1365.Fn namei 1366routine, the 1367.Xr ccd 4 1368driver, 1369and much of the networking code. 1370.It Cd options MAXUPRC=integer 1371Sets the soft 1372.Dv RLIMIT_NPROC 1373resource limit, which specifies the maximum number of simultaneous 1374processes a user is permitted to run, for process 0; 1375this value is inherited by its child processes. 1376It defaults to 1377.Em CHILD_MAX , 1378which is currently defined to be 160. 1379Setting 1380.Em MAXUPRC 1381to a value less than 1382.Em CHILD_MAX 1383is not permitted, as this would result in a violation of the semantics of 1384.St -p1003.1-90 . 1385.It Cd options NOFILE=integer 1386Sets the soft 1387.Dv RLIMIT_NOFILE 1388resource limit, which specifies the maximum number of open 1389file descriptors for each process; 1390this value is inherited by its child processes. 1391It defaults to 1392.Em OPEN_MAX , 1393which is currently defined to be 64. 1394.It Cd options MAXFILES=integer 1395Sets the default value of the 1396.Em kern.maxfiles 1397sysctl variable, which indicates the maximum number of files that may 1398be open in the system. 1399.It Cd options DEFCORENAME=string 1400Sets the default value of the 1401.Em kern.defcorename 1402sysctl variable, otherwise it is set to 1403.Nm %n.core . 1404See 1405.Xr sysctl 8 1406and 1407.Xr sysctl 3 1408for details. 1409.It Cd options RASOPS_CLIPPING 1410Enables clipping within the 1411.Nm rasops 1412raster-console output system. 1413.Em NOTE : 1414only available on architectures that use 1415.Nm rasops 1416for console output. 1417.It Cd options RASOPS_SMALL 1418Removes optimized character writing code from the 1419.Nm rasops 1420raster-console output system. 1421.Em NOTE : 1422only available on architectures that use 1423.Nm rasops 1424for console output. 1425.It Cd options INCLUDE_CONFIG_FILE 1426Embeds the kernel config file used to define the kernel in the kernel 1427binary itself. 1428The embedded data also includes any files directly included by the config 1429file itself, e.g. 1430.Pa GENERIC.local 1431or 1432.Pa std.$MACHINE . 1433The embedded config file can be extracted from the resulting kernel with 1434.Xr config 1 1435.Fl x , 1436or by the following command: 1437.Bd -literal -offset indent 1438strings netbsd | sed -n 's/^_CFG_//p' | unvis 1439.Ed 1440.It Cd options INCLUDE_JUST_CONFIG 1441Similar to the above option, but includes just the actual config file, 1442not any included files. 1443.It Cd options PIPE_SOCKETPAIR 1444Use slower, but smaller socketpair(2)-based pipe implementation instead 1445of default faster, but bigger one. 1446Primarily useful for installation kernels. 1447.It Cd options USERCONF 1448Compiles in the in-kernel device configuration manager. 1449See 1450.Xr userconf 4 1451for details. 1452.It Cd options PERFCTRS 1453Compiles in kernel support for CPU performance-monitoring counters. 1454See 1455.Xr pmc 1 1456for details. 1457.Em NOTE : 1458not available on all architectures. 1459.It Cd options SYSCALL_STATS 1460Count the number of times each system call number is called. 1461The values can be read through the sysctl interface and displayed using 1462.Xr systat 1 . 1463.Em NOTE : 1464not yet available on all architectures. 1465.It Cd options SYSCALL_TIMES 1466Count the time spent (using 1467.Fn cpu_counter32 ) 1468in each system call. 1469.Em NOTE : 1470Using this option will also enable 1471.Cd options SYSCALL_STATS . 1472.It Cd options SYSCALL_TIMES_HASCOUNTER 1473Force use of 1474.Fn cpu_counter32 1475even if 1476.Fn cpu_hascounter 1477reports false. 1478Useful for systems where the cycle counter doesn't run at a constant rate 1479(e.g. Soekris boxes). 1480.It Cd options XSERVER 1481Compiles in kernel support for 1482.Tn X11 1483on architectures that still use (or can use) the legacy 1484.Em pccons 1485console drivers rather than 1486.Xr wscons 4 . 1487These include bebox, i386, shark. 1488.It Cd options XSERVER_DDB 1489A supplement to XSERVER that adds support for entering 1490.Xr ddb 4 1491while in 1492.Tn X11 . 1493.It Cd options FILEASSOC 1494Support for 1495.Xr fileassoc 9 . 1496.It Cd options FILEASSOC_NHOOKS=integer 1497Number of storage slots per file for 1498.Xr fileassoc 9 . 1499Default is 4. 1500.It Cd options I2C_SCAN 1501Scan each i2c bus to determine which addresses respond. 1502.Pp 1503.Em WARNING ! 1504Using this option can access some devices in such a 1505manner as to leave them in an unstable or unuseable state, and 1506can prevent those devices from being properly matched and/or 1507attached. 1508It can also lock up the entire i2c bus and even 1509prevent a machine from completing the boot process. 1510Don't use this option unless you know what you're doing and can 1511accept all sorts of unforeseen consequences. 1512.El 1513.Ss Networking Options 1514.Bl -ohang 1515.It Cd options GATEWAY 1516Enables 1517.Em IPFORWARDING 1518(which see) 1519and (on most ports) increases the size of 1520.Em NMBCLUSTERS 1521(which see). 1522In general, 1523.Em GATEWAY 1524is used to indicate that a system should act as a router, and 1525.Em IPFORWARDING 1526is not invoked directly. 1527(Note that 1528.Em GATEWAY 1529has no impact on protocols other than 1530.Tn IP , 1531such as 1532.Tn CLNP 1533or 1534.Tn XNS ) . 1535.Em GATEWAY 1536option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1537.It Cd options ICMPPRINTFS 1538The 1539.Em ICMPPRINTFS 1540option will enable debugging information to be printed about 1541the 1542.Xr icmp 4 1543protocol. 1544.It Cd options IPFORWARDING=value 1545If 1546.Em value 1547is 1 this enables IP routing behavior. 1548If 1549.Em value 1550is 0 (the default), it disables it. 1551The 1552.Em GATEWAY 1553option sets this to 1 automatically. 1554With this option enabled, the machine will forward IP datagrams destined 1555for other machines between its interfaces. 1556Note that even without this option, the kernel will 1557still forward some packets (such as source routed packets) -- removing 1558.Em GATEWAY 1559and 1560.Em IPFORWARDING 1561is insufficient to stop all routing through a bastion host on a 1562firewall -- source routing is controlled independently. 1563To turn off source routing, use 1564.Em options IPFORWSRCRT=0 1565(which see). 1566Note that IP forwarding may be turned on and off independently of the 1567setting of the 1568.Em IPFORWARDING 1569option through the use of the 1570.Em net.inet.ip.forwarding 1571sysctl variable. 1572If 1573.Em net.inet.ip.forwarding 1574is 1, IP forwarding is on. 1575See 1576.Xr sysctl 8 1577and 1578.Xr sysctl 3 1579for details. 1580.It Cd options IPFORWSRCRT=value 1581If 1582.Em value 1583is set to zero, source routing of IP datagrams is turned off. 1584If 1585.Em value 1586is set to one (the default) or the option is absent, source routed IP 1587datagrams are forwarded by the machine. 1588Note that source routing of IP packets may be turned on and off 1589independently of the setting of the 1590.Em IPFORWSRCRT 1591option through the use of the 1592.Em net.inet.ip.forwsrcrt 1593sysctl variable. 1594If 1595.Em net.inet.ip.forwsrcrt 1596is 1, forwarding of source routed IP datagrams is on. 1597See 1598.Xr sysctl 8 1599and 1600.Xr sysctl 3 1601for details. 1602.It Cd options IFA_STATS 1603Tells the kernel to maintain per-address statistics on bytes sent 1604and received over (currently) Internet and AppleTalk addresses. 1605.\"This can be a fairly expensive operation, so you probably want to 1606.\"keep this disabled. 1607The option is not recommended as it degrades system stability. 1608.It Cd options IFQ_MAXLEN=value 1609Increases the allowed size of the network interface packet queues. 1610The default queue size is 50 packets, and you do not normally need 1611to increase it. 1612.It Cd options IPSELSRC 1613Includes support for source-address selection policies. 1614See 1615.Xr in_getifa 9 . 1616.It Cd options MROUTING 1617Includes support for IP multicast routers. 1618You certainly want 1619.Em INET 1620with this. 1621Multicast routing is controlled by the 1622.Xr mrouted 8 1623daemon. 1624See also option 1625.Cd PIM . 1626.It Cd options PIM 1627Includes support for Protocol Independent Multicast (PIM) routing. 1628You need 1629.Em MROUTING 1630and 1631.Em INET 1632with this. 1633Software using this can be found e.g. in 1634.Pa pkgsrc/net/xorp . 1635.It Cd options INET 1636Includes support for the 1637.Tn TCP/IP 1638protocol stack. 1639You almost certainly want this. 1640See 1641.Xr inet 4 1642for details. 1643.It Cd options INET6 1644Includes support for the 1645.Tn IPv6 1646protocol stack. 1647See 1648.Xr inet6 4 1649for details. 1650Unlike 1651.Em INET , 1652.Em INET6 1653enables multicast routing code as well. 1654This option requires 1655.Em INET 1656at this moment, but it should not. 1657.It Cd options ND6_DEBUG 1658The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1659for debugging IPv6 neighbor discovery protocol handling. 1660See 1661.Xr sysctl 3 1662for details. 1663.It Cd options IPSEC 1664Includes support for the 1665.Tn IPsec 1666protocol. 1667See 1668.Xr ipsec 4 1669for details. 1670.It Cd options IPSEC_DEBUG 1671Enables debugging code in 1672.Tn IPsec 1673stack. 1674See 1675.Xr ipsec 4 1676for details. 1677.It Cd options IPSEC_ESP 1678Includes support for 1679.Tn IPsec 1680.Tn ESP 1681protocol. 1682See 1683.Xr ipsec 4 1684for details. 1685.It Cd options IPSEC_NAT_T 1686Includes support for 1687.Tn IPsec 1688Network Address Translator traversal (NAT-T), as described in RFCs 3947 1689and 3948. 1690This feature might be patent-encumbered in some countries. 1691.It Cd options ALTQ 1692Enabled ALTQ (Alternate Queueing). 1693For simple rate-limiting, use 1694.Xr tbrconfig 8 1695to set up the interface transmission rate. 1696To use queueing disciplines, their appropriate kernel options should also 1697be defined (documented below). 1698Queueing disciplines are managed by 1699.Xr altqd 8 . 1700See 1701.Xr altq 9 1702for details. 1703.It Cd options ALTQ_HFSC 1704Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1705module. 1706HFSC supports both link-sharing and guaranteed real-time services. 1707HFSC employs a service curve based QoS model, and its unique feature 1708is an ability to decouple delay and bandwidth allocation. 1709Requires 1710.Em ALTQ_RED 1711to use the RED queueing discipline on HFSC classes, or 1712.Em ALTQ_RIO 1713to use the RIO queueing discipline on HFSC classes. 1714This option assumes 1715.Em ALTQ . 1716.It Cd options ALTQ_PRIQ 1717Include support for ALTQ-implemented PRIQ (Priority Queueing). 1718PRIQ implements a simple priority-based queueing discipline. 1719A higher priority class is always served first. 1720Requires 1721.Em ALTQ_RED 1722to use the RED queueing discipline on HFSC classes, or 1723.Em ALTQ_RIO 1724to use the RIO queueing discipline on HFSC classes. 1725This option assumes 1726.Em ALTQ . 1727.It Cd options ALTQ_WFQ 1728Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1729WFQ implements a weighted-round robin scheduler for a set of queues. 1730A weight can be assigned to each queue to give a different proportion 1731of the link capacity. 1732A hash function is used to map a flow to one of a set of queues. 1733This option assumes 1734.Em ALTQ . 1735.It Cd options ALTQ_FIFOQ 1736Include support for ALTQ-implemented FIFO queueing. 1737FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1738This option assumes 1739.Em ALTQ . 1740.It Cd options ALTQ_RIO 1741Include support for ALTQ-implemented RIO (RED with In/Out). 1742The original RIO has 2 sets of RED parameters; one for in-profile 1743packets and the other for out-of-profile packets. 1744At the ingress of the network, profile meters tag packets as IN or 1745OUT based on contracted profiles for customers. 1746Inside the network, IN packets receive preferential treatment by 1747the RIO dropper. 1748ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1749PHB of DiffServ (RFC 2597). 1750This option assumes 1751.Em ALTQ . 1752.It Cd options ALTQ_BLUE 1753Include support for ALTQ-implemented Blue buffer management. 1754Blue is another active buffer management mechanism. 1755This option assumes 1756.Em ALTQ . 1757.It Cd options ALTQ_FLOWVALVE 1758Include support for ALTQ-implemented Flowvalve. 1759Flowvalve is a simple implementation of a RED penalty box that identifies 1760and punishes misbehaving flows. 1761This option requires 1762.Em ALTQ_RED 1763and assumes 1764.Em ALTQ . 1765.It Cd options ALTQ_CDNR 1766Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1767packet marking/manipulation. 1768Traffic conditioners are components to meter, mark, or drop incoming 1769packets according to some rules. 1770As opposed to queueing disciplines, traffic conditioners handle incoming 1771packets at an input interface. 1772This option assumes 1773.Em ALTQ . 1774.It Cd options ALTQ_NOPCC 1775Disables use of processor cycle counter to measure time in ALTQ. 1776This option should be defined for a non-Pentium i386 CPU which does not 1777have TSC, SMP (per-CPU counters are not in sync), or power management 1778which affects processor cycle counter. 1779This option assumes 1780.Em ALTQ . 1781.It Cd options ALTQ_IPSEC 1782Include support for IPsec in IPv4 ALTQ. 1783This option assumes 1784.Em ALTQ . 1785.It Cd options ALTQ_JOBS 1786Include support for ALTQ-implemented JoBS (Joint Buffer Management 1787and Scheduling). 1788This option assumes 1789.Em ALTQ . 1790.It Cd options ALTQ_AFMAP 1791Include support for an undocumented ALTQ feature that is used to map an IP 1792flow to an ATM VC (Virtual Circuit). 1793This option assumes 1794.Em ALTQ . 1795.It Cd options ALTQ_LOCALQ 1796Include support for ALTQ-implemented local queues. 1797Its practical use is undefined. 1798Assumes 1799.Em ALTQ . 1800.It Cd options SUBNETSARELOCAL 1801Sets default value for net.inet.ip.subnetsarelocal variable, which 1802controls whether non-directly-connected subnets of connected networks 1803are considered "local" for purposes of choosing the MSS for a TCP 1804connection. 1805This is mostly present for historic reasons and completely irrelevant if 1806you enable Path MTU discovery. 1807.It Cd options HOSTZEROBROADCAST 1808Sets default value for net.inet.ip.hostzerobroadcast variable, which 1809controls whether the zeroth host address of each connected subnet is 1810also considered a broadcast address. 1811Default value is "1", for compatibility with old systems; if this is 1812set to zero on all hosts on a subnet, you should be able to fit an extra 1813host per subnet on the 1814".0" address. 1815.It Cd options MCLSHIFT=value 1816This option is the base-2 logarithm of the size of mbuf clusters. 1817The 1818.Bx 1819networking stack keeps network packets in a linked 1820list, or chain, of kernel buffer objects called mbufs. 1821The system provides larger mbuf clusters as an optimization for 1822large packets, instead of using long chains for large packets. 1823The mbuf cluster size, 1824or 1825.Em MCLBYTES , 1826must be a power of two, and is computed as two raised to the power 1827.Em MCLSHIFT . 1828On systems with Ethernet network adapters, 1829.Em MCLSHIFT 1830is often set to 11, giving 2048-byte mbuf clusters, large enough to 1831hold a 1500-byte 1832.Tn Ethernet 1833frame in a single cluster. 1834Systems with network interfaces supporting larger frame sizes like 1835.Tn ATM , 1836.Tn FDDI , 1837or 1838.Tn HIPPI 1839may perform better with 1840.Em MCLSHIFT 1841set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1842respectively. 1843.It Cd options NS 1844Include support for the 1845.Tn Xerox 1846.Tn XNS 1847protocol stack. 1848See 1849.Xr ns 4 1850for details. 1851.It Cd options ISO,TPIP 1852Include support for the ubiquitous 1853.Tn OSI 1854protocol stack. 1855See 1856.Xr iso 4 1857for details. 1858This option assumes 1859.Em INET . 1860.It Cd options EON 1861Include support for tunneling 1862.Tn OSI 1863protocols over 1864.Tn IP . 1865Known to be broken, or at least very fragile, and undocumented. 1866.It Cd options NETATALK 1867Include support for the 1868.Tn AppleTalk 1869protocol stack. 1870The kernel provides provision for the 1871.Em Datagram Delivery Protocol 1872(DDP), providing SOCK_DGRAM support and 1873.Tn AppleTalk 1874routing. 1875This stack is used by the 1876.Em NETATALK 1877package, which adds support for 1878.Tn AppleTalk 1879server services via user libraries and applications. 1880.It Cd options BLUETOOTH 1881Include support for the 1882.Tn Bluetooth 1883protocol stack. 1884See 1885.Xr bluetooth 4 1886for details. 1887.It Cd options IPNOPRIVPORTS 1888Normally, only root can bind a socket descriptor to a so-called 1889.Dq privileged 1890.Tn TCP 1891port, that is, a port number in the range 0-1023. 1892This option eliminates those checks from the kernel. 1893This can be useful if there is a desire to allow daemons without 1894privileges to bind those ports, e.g., on firewalls. 1895The security tradeoffs in doing this are subtle. 1896This option should only be used by experts. 1897.It Cd options TCP_COMPAT_42 1898.Tn TCP 1899bug compatibility with 1900.Bx 4.2 . 1901In 1902.Bx 4.2 , 1903.Tn TCP 1904sequence numbers were 32-bit signed values. 1905Modern implementations of TCP use unsigned values. 1906This option clamps the initial sequence number to start in 1907the range 2^31 rather than the full unsigned range of 2^32. 1908Also, under 1909.Bx 4.2 , 1910keepalive packets must contain at least one byte or else 1911the remote end would not respond. 1912.It Cd options TCP_DEBUG 1913Record the last 1914.Em TCP_NDEBUG 1915TCP packets with SO_DEBUG set, and decode to the console if 1916.Em tcpconsdebug 1917is set. 1918.It Cd options TCP_NDEBUG 1919Number of packets to record for 1920.Em TCP_DEBUG . 1921Defaults to 100. 1922.It Cd options TCP_SENDSPACE=value 1923.It Cd options TCP_RECVSPACE=value 1924These options set the max TCP window size to other sizes than the default. 1925The TCP window sizes can be altered via 1926.Xr sysctl 8 1927as well. 1928.It Cd options TCP_INIT_WIN=value 1929This option sets the initial TCP window size for non-local connections, 1930which is used when the transmission starts. 1931The default size is 1, but if the machine should act more aggressively, 1932the initial size can be set to some other value. 1933The initial TCP window size can be set via 1934.Xr sysctl 8 1935as well. 1936.It Cd options PFIL_HOOKS 1937This option turns on the packet filter interface hooks. 1938See 1939.Xr pfil 9 1940for details. 1941This option assumes 1942.Em INET . 1943.It Cd options IPFILTER_LOG 1944This option, in conjunction with 1945.Em pseudo-device ipfilter , 1946enables logging of IP packets using ip-filter. 1947.It Cd options IPFILTER_DEFAULT_BLOCK 1948This option sets the default policy of ip-filter. 1949If it is set, ip-filter will block packets by default. 1950.It Cd options BRIDGE_IPF 1951This option causes 1952.Em bridge 1953devices to use the IP and/or IPv6 filtering hooks, forming 1954a link-layer filter that uses protocol-layer rules. 1955This option assumes the presence of 1956.Em pseudo-device ipfilter . 1957.It Cd options MBUFTRACE 1958This option can help track down mbuf leaks. 1959When enabled, mbufs are tagged with the devices and protocols using them, 1960which slightly decreases network performance. 1961This additional information can be viewed with 1962.Xr netstat 1 : 1963.Dl Ic netstat Fl mssv 1964Not all devices or protocols support this option. 1965.El 1966.Ss Sysctl Related Options 1967.Bl -ohang 1968.It Cd options SYSCTL_DISALLOW_CREATE 1969Disallows the creation or deletion of nodes from the sysctl tree, as 1970well as the assigning of descriptions to nodes that lack them, by any 1971process. 1972These operations are still available to kernel sub-systems, including 1973loadable kernel modules. 1974.It Cd options SYSCTL_DISALLOW_KWRITE 1975Prevents processes from adding nodes to the sysctl tree that make 1976existing kernel memory areas writable. 1977Sections of kernel memory can still be read and new nodes that own 1978their own data may still be writable. 1979.It Cd options SYSCTL_DEBUG_SETUP 1980Causes the SYSCTL_SETUP routines to print a brief message when they 1981are invoked. 1982This is merely meant as an aid in determining the order in which 1983sections of the tree are created. 1984.It Cd options SYSCTL_DEBUG_CREATE 1985Prints a message each time 1986.Fn sysctl_create , 1987the function that adds nodes to the tree, is called. 1988.It Cd options SYSCTL_INCLUDE_DESCR 1989Causes the kernel to include short, human readable descriptions for 1990nodes in the sysctl tree. 1991The descriptions can be retrieved programmatically (see 1992.Xr sysctl 3 ) , 1993or by the sysctl binary itself (see 1994.Xr sysctl 8 ) . 1995The descriptions are meant to give an indication of the purpose and/or 1996effects of a given node's value, not replace the documentation for the 1997given subsystem as a whole. 1998.El 1999.Ss System V IPC Options 2000.Bl -ohang 2001.It Cd options SYSVMSG 2002Includes support for 2003.At V 2004style message queues. 2005See 2006.Xr msgctl 2 , 2007.Xr msgget 2 , 2008.Xr msgrcv 2 , 2009.Xr msgsnd 2 . 2010.It Cd options SYSVSEM 2011Includes support for 2012.At V 2013style semaphores. 2014See 2015.Xr semctl 2 , 2016.Xr semget 2 , 2017.Xr semop 2 . 2018.It Cd options SEMMNI=value 2019Sets the number of 2020.At V 2021style semaphore identifiers. 2022The GENERIC config file for your port will have the default. 2023.It Cd options SEMMNS=value 2024Sets the number of 2025.At V 2026style semaphores in the system. 2027The GENERIC config file for your port will have the default. 2028.It Cd options SEMUME=value 2029Sets the maximum number of undo entries per process for 2030.At V 2031style semaphores. 2032The GENERIC config file for your port will have the default. 2033.It Cd options SEMMNU=value 2034Sets the number of undo structures in the system for 2035.At V 2036style semaphores. 2037The GENERIC config file for your port will have the default. 2038.It Cd options SYSVSHM 2039Includes support for 2040.At V 2041style shared memory. 2042See 2043.Xr shmat 2 , 2044.Xr shmctl 2 , 2045.Xr shmdt 2 , 2046.Xr shmget 2 . 2047.It Cd options SHMMAXPGS=value 2048Sets the maximum number of 2049.At V 2050style shared memory pages that are available through the 2051.Xr shmget 2 2052system call. 2053Default value is 1024 on most ports. 2054See 2055.Pa /usr/include/machine/vmparam.h 2056for the default. 2057.El 2058.Ss VM Related Options 2059.Bl -ohang 2060.It Cd options NMBCLUSTERS=value 2061The number of mbuf clusters the kernel supports. 2062Mbuf clusters are MCLBYTES in size (usually 2k). 2063This is used to compute the size of the kernel VM map 2064.Em mb_map , 2065which maps mbuf clusters. 2066Default on most ports is 1024 (2048 with 2067.Dq options GATEWAY 2068). 2069See 2070.Pa /usr/include/machine/param.h 2071for exact default information. 2072Increase this value if you get 2073.Dq mclpool limit reached 2074messages. 2075.It Cd options NKMEMPAGES=value 2076.It Cd options NKMEMPAGES_MIN=value 2077.It Cd options NKMEMPAGES_MAX=value 2078Size of kernel VM map 2079.Em kmem_map , 2080in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2081from the 2082.Xr sysctl 8 2083variable 2084.Em hw.pagesize 2085). 2086This VM map is used to map the kernel malloc arena. 2087The kernel attempts to auto-size this map based on the amount of 2088physical memory in the system. 2089Platform-specific code may place bounds on this computed size, 2090which may be viewed with the 2091.Xr sysctl 8 2092variable 2093.Em vm.nkmempages . 2094See 2095.Pa /usr/include/machine/param.h 2096for the default upper and lower bounds. 2097The related options 2098.Sq NKMEMPAGES_MIN 2099and 2100.Sq NKMEMPAGES_MAX 2101allow the bounds to be overridden in the kernel configuration file. 2102These options are provided in the event the computed value is 2103insufficient resulting in an 2104.Dq out of space in kmem_map 2105panic. 2106.It Cd options SB_MAX=value 2107Sets the max size in bytes that a socket buffer is allowed to occupy. 2108The default is 256k, but sometimes it needs to be increased, for example 2109when using large TCP windows. 2110This option can be changed via 2111.Xr sysctl 8 2112as well. 2113.It Cd options SOMAXKVA=value 2114Sets the maximum size of kernel virtual memory that the socket buffers 2115are allowed to use. 2116The default is 16MB, but in situations where for example large TCP 2117windows are used this value must also be increased. 2118This option can be changed via 2119.Xr sysctl 8 2120as well. 2121.It Cd options BUFCACHE=value 2122Size of the buffer cache as a percentage of total available 2123.Tn RAM . 2124Ignored if BUFPAGES is also specified. 2125.It Cd options NBUF=value 2126Sets the number of buffer headers available, i.e., the number of 2127open files that may have a buffer cache entry. 2128Each buffer header 2129requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2130The default value is machine dependent, but is usually equal to the 2131value of BUFPAGES. 2132If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2133then NBUF may be reduced at run time so that the storage allocated 2134for buffer headers doesn't exceed that limit. 2135.It Cd options BUFPAGES=value 2136These options set the number of pages available for the buffer cache. 2137Their default value is a machine dependent value, often calculated as 2138between 5% and 10% of total available 2139.Tn RAM . 2140.It Cd options MAXTSIZ=bytes 2141Sets the maximum size limit of a process' text segment. 2142See 2143.Pa /usr/include/machine/vmparam.h 2144for the port-specific default. 2145.It Cd options DFLDSIZ=bytes 2146Sets the default size limit of a process' data segment, the value that 2147will be returned as the soft limit for 2148.Dv RLIMIT_DATA 2149(as returned by 2150.Xr getrlimit 2 ) . 2151See 2152.Pa /usr/include/machine/vmparam.h 2153for the port-specific default. 2154.It Cd options MAXDSIZ=bytes 2155Sets the maximum size limit of a process' data segment, the value that 2156will be returned as the hard limit for 2157.Dv RLIMIT_DATA 2158(as returned by 2159.Xr getrlimit 2 ) . 2160See 2161.Pa /usr/include/machine/vmparam.h 2162for the port-specific default. 2163.It Cd options DFLSSIZ=bytes 2164Sets the default size limit of a process' stack segment, the value that 2165will be returned as the soft limit for 2166.Dv RLIMIT_STACK 2167(as returned by 2168.Xr getrlimit 2 ) . 2169See 2170.Pa /usr/include/machine/vmparam.h 2171for the port-specific default. 2172.It Cd options MAXSSIZ=bytes 2173Sets the maximum size limit of a process' stack segment, the value that 2174will be returned as the hard limit for 2175.Dv RLIMIT_STACK 2176(as returned by 2177.Xr getrlimit 2 ) . 2178See 2179.Pa /usr/include/machine/vmparam.h 2180for the port-specific default. 2181.It Cd options DUMP_ON_PANIC=integer 2182Defaults to one. 2183If set to zero, the kernel will not dump to the dump device when 2184it panics, though dumps can still be forced via 2185.Xr ddb 4 2186with the 2187.Dq sync 2188command. 2189Note that this sets the value of the 2190.Em kern.dump_on_panic 2191.Xr sysctl 3 2192variable which may be changed at run time -- see 2193.Xr sysctl 8 2194for details. 2195.It Cd options USE_TOPDOWN_VM 2196User space memory allocations (as made by 2197.Xr mmap 2 ) 2198will be arranged in a 2199.Dq top down 2200fashion instead of the traditional 2201.Dq upwards from MAXDSIZ \&+ vm_daddr 2202method. 2203This includes the placement of 2204.Xr ld.so 1 . 2205Arranging memory in this manner allows either (or both of) the heap or 2206.Xr mmap 2 2207allocated space to grow larger than traditionally possible. 2208This option is not available on all ports, but is instead expected to be 2209offered on a port-by-port basis, after which some ports will commit to 2210using it by default. 2211See the files 2212.Pa /usr/include/uvm/uvm_param.h 2213for some implementation details, and 2214.Pa /usr/include/machine/vmparam.h 2215for port specific details including availability. 2216.It Cd options VMSWAP 2217Enable paging device/file support. 2218This option is on by default. 2219.It Cd options PDPOLICY_CLOCKPRO 2220Use CLOCK-Pro, an alternative page replace policy. 2221.El 2222.Ss Security Options 2223.Bl -ohang 2224.It Cd options INSECURE 2225Hardwires the kernel security level at \-1. 2226This means that the system 2227always runs in secure level \-1 mode, even when running multiuser. 2228See the manual page for 2229.Xr init 8 2230for details on the implications of this. 2231The kernel secure level may manipulated by the superuser by altering the 2232.Em kern.securelevel 2233.Xr sysctl 3 2234variable (the secure level may only be lowered by a call from process ID 1, 2235i.e., 2236.Xr init 8 ) . 2237See also 2238.Xr secmodel_securelevel 9 , 2239.Xr sysctl 8 2240and 2241.Xr sysctl 3 . 2242.It Cd options VERIFIED_EXEC_FP_MD5 2243Enables support for MD5 hashes in Veriexec. 2244.It Cd options VERIFIED_EXEC_FP_SHA1 2245Enables support for SHA1 hashes in Veriexec. 2246.It Cd options VERIFIED_EXEC_FP_RMD160 2247Enables support for RMD160 hashes in Veriexec. 2248.It Cd options VERIFIED_EXEC_FP_SHA256 2249Enables support for SHA256 hashes in Veriexec. 2250.It Cd options VERIFIED_EXEC_FP_SHA384 2251Enables support for SHA384 hashes in Veriexec. 2252.It Cd options VERIFIED_EXEC_FP_SHA512 2253Enables support for SHA512 hashes in Veriexec. 2254.It Cd options PAX_MPROTECT=value 2255Enables PaX MPROTECT, 2256.Xr mprotect 2 2257restrictions from the PaX project. 2258.Pp 2259The 2260.Ar value 2261is the default value for the 2262.Em global 2263knob, see 2264.Xr sysctl 3 . 2265If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2266using 2267.Xr paxctl 8 . 2268If 1, PaX MPROTECT will be enabled for all programs. 2269Programs can be exempted using 2270.Xr paxctl 8 . 2271.Pp 2272See 2273.Xr security 8 2274for more details. 2275.It Cd options PAX_SEGVGUARD=value 2276Enables PaX Segvguard. 2277.Pp 2278The 2279.Ar value 2280is the default value for the 2281.Em global 2282knob, see 2283.Xr sysctl 3 . 2284If 0, PaX Segvguard will be enabled only if explicitly set on programs 2285using 2286.Xr paxctl 8 . 2287If 1, PaX Segvguard will be enabled to all programs, and exemption can 2288be done using 2289.Xr paxctl 8 . 2290.Pp 2291See 2292.Xr security 8 2293for more details. 2294.It Cd options PAX_ASLR=value 2295Enables PaX ASLR. 2296.Pp 2297The 2298.Ar value 2299is the default value for the 2300.Em global 2301knob, see 2302.Xr sysctl 3 . 2303If 0, PaX ASLR will be enabled only if explicitly set on programs 2304using 2305.Xr paxctl 8 . 2306If 1, PaX ASLR will be enabled to all programs, and exemption can 2307be done using 2308.Xr paxctl 8 . 2309.Pp 2310See 2311.Xr security 8 2312for more details. 2313.El 2314.Ss amiga-specific Options 2315.Bl -ohang 2316.It Cd options BB060STUPIDROM 2317When the bootloader (which passes 2318.Tn AmigaOS 2319.Tn ROM 2320information) claims we have a 68060 2321.Tn CPU 2322without 2323.Tn FPU , 2324go look into the Processor Configuration Register (PCR) to find out. 2325You need this with 2326.Tn Amiga 2327.Tn ROM Ns s 2328up to (at least) V40.xxx (OS3.1), 2329when you boot via the bootblocks and don't have a DraCo. 2330.It Cd options IOBZCLOCK=frequency 2331The IOBlix boards come with two different serial master clocks: older ones 2332use 24 MHz, newer ones use 22.1184 MHz. 2333The driver normally assumes the latter. 2334If your board uses 24 MHz, you can recompile your kernel with 2335options IOBZCLOCK=24000000 2336or patch the kernel variable 2337.Tn iobzclock 2338to the same value. 2339.It Cd options LIMITMEM=value 2340If there, limit the part of the first memory bank used by 2341.Nx 2342to value megabytes. 2343Default is unlimited. 2344.It Cd options NKPTADD=addvalue 2345.It Cd options NKPTADDSHIFT=shiftvalue 2346The 2347.Tn CPU 2348specific 2349.Tn MMU 2350table for the kernel is pre-allocated at kernel startup time. 2351Part of it is scaled with 2352.Va maxproc , 2353to have enough room to hold the user program 2354.Tn MMU 2355tables; the second part is a fixed amount for the kernel itself. 2356.Pp 2357The third part accounts for the size of the file buffer cache. 2358Its size is either 2359.Dv NKPTADD 2360pages (if defined) or memory size in bytes divided by two to 2361the power of 2362.Dv NKPTADDSHIFT . 2363The default is undefined 2364.Dv NKPTADD 2365and 2366.Dv NKPTADDSHIFT=24 , 2367allowing for 16 buffers per megabyte of main memory (while 2368a GENERIC kernel allocates about half of that). 2369When you get "can't get KPT page" panics, you should increase 2370.Dv NKPTADD 2371(if defined), or decrease 2372.Dv NKPTADDSHIFT 2373by one. 2374.It Cd options P5PPC68KBOARD 2375Add special support for Phase5 mixed 68k+PPC boards. 2376Currently, this only affects rebooting from 2377.Nx 2378and is only needed on 68040+PPC, not on 237968060+PPC; without this, affected machines will hang after 2380.Nx 2381has shut 2382down and will only restart after a keyboard reset or a power cycle. 2383.El 2384.Ss arm32-specific Options 2385.Bl -ohang 2386.It Cd options FRENCH_KBD 2387Include translation for French keyboards when using 2388.Em pccons 2389on a Shark. 2390.It Cd options FINNISH_KBD 2391Include translation for Finnish keyboards when using 2392.Em pccons 2393on a Shark. 2394.It Cd options GERMAN_KBD 2395Include translation for German keyboards when using 2396.Em pccons 2397on a Shark. 2398.It Cd options NORWEGIAN_KBD 2399Include translation for French keyboards when using 2400.Em pccons 2401on a Shark. 2402.El 2403.Ss amd64-specific Options 2404.Bl -ohang 2405.It Cd options ENHANCED_SPEEDSTEP 2406Include support for the 2407.Tn Enhanced SpeedStep Technology 2408present in newer 2409.Tn CPU Ns s . 2410.It Cd options EST_FREQ_USERWRITE 2411Allow any user to change the frequency of an 2412.Tn Enhanced SpeedStep Technology 2413capable 2414.Tn CPU . 2415.It Cd options INTEL_ONDEMAND_CLOCKMOD 2416This enables the On Demand Clock Modulation by software 2417on Intel 2418.Tn CPUs 2419supporting the Thermal Monitor feature (TM). 2420You can select the duty cycle with 2421.Xr sysctl 8 2422in the node 2423.Em machdep.clockmod 2424if supported. 2425.It Cd options POWERNOW_K8 2426Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2427Technology, used to change the CPU voltage and frequency 2428on the fly. 2429.El 2430.Ss atari-specific Options 2431.Bl -ohang 2432.It Cd options DISKLABEL_AHDI 2433Include support for AHDI (native Atari) disklabels. 2434.It Cd options DISKLABEL_NBDA 2435Include support for 2436.Nx Ns Tn /atari 2437labels. 2438If you don't set this option, it will be set automatically. 2439.Nx Ns Tn /atari 2440will not work without it. 2441.It Cd options FALCON_SCSI 2442Include support for the 5380-SCSI configuration as found on the Falcon. 2443.It Cd options RELOC_KERNEL 2444If set, the kernel will relocate itself to TT-RAM, if possible. 2445This will give you a slightly faster system. 2446.Em Beware 2447that on some TT030 systems, 2448the system will frequently dump with MMU-faults with this option enabled. 2449.It Cd options SERCONSOLE 2450Allow the modem1-port to act as the system-console. 2451A carrier should be active on modem1 during system boot to active 2452the console functionality. 2453.It Cd options TT_SCSI 2454Include support for the 5380-SCSI configuration as found on the TT030 2455and Hades. 2456.El 2457.Ss i386-specific Options 2458.Bl -ohang 2459.It Cd options ENHANCED_SPEEDSTEP 2460Include support for the 2461.Tn Enhanced SpeedStep Technology 2462present in newer 2463.Tn CPU Ns s . 2464.It Cd options EST_FREQ_USERWRITE 2465Allow any user to change the frequency of an 2466.Tn Enhanced SpeedStep Technology 2467capable 2468.Tn CPU . 2469.It Cd options INTEL_ONDEMAND_CLOCKMOD 2470This enables the On Demand Clock Modulation by software 2471on Intel 2472.Tn CPUs 2473supporting the Thermal Monitor feature (TM). 2474You can select the duty cycle with 2475.Xr sysctl 8 2476in the node 2477.Em machdep.clockmod 2478if supported. 2479.It Cd options POWERNOW_K7 2480Include support for the AMD 2481.Tn PowerNow! Technology 2482present in AMD Athlon Mobile processors. 2483.It Cd options VIA_PADLOCK 2484Include support for the 2485.Tn AES 2486encryption instructions of the 2487.Tn VIA PadLock Security engine , 2488which is attached as a provider to the opencrypto framework. 2489.It Cd options CPURESET_DELAY=value 2490Specifies the time (in millisecond) to wait before doing a hardware reset 2491in the last phase of a reboot. 2492This gives the user a chance to see error messages from the shutdown 2493operations (like NFS unmounts, buffer cache flush, etc ...). 2494Setting this to 0 will disable the delay. 2495Default is 2 seconds. 2496.It Cd options VM86 2497Include support for virtual 8086 mode, used by 2498.Tn DOS 2499emulators and X servers to run BIOS code, e.g., for some VESA routines. 2500.It Cd options USER_LDT 2501Include i386-specific system calls for modifying the local descriptor table, 2502used by Windows emulators. 2503.It Cd options REALBASEMEM=integer 2504Overrides the base memory size passed in from the boot block. 2505(Value given in kilobytes.) 2506Use this option only if the boot block reports the size incorrectly. 2507(Note that some 2508.Tn BIOS Ns es 2509put the extended 2510.Tn BIOS 2511data area at the top of base memory, and therefore report a smaller 2512base memory size to prevent programs overwriting it. 2513This is correct behavior, and you should not use the 2514.Em REALBASEMEM 2515option to access this memory). 2516.It Cd options REALEXTMEM=integer 2517Overrides the extended memory size passed in from the boot block. 2518(Value given in kilobytes. 2519Extended memory does not include the first megabyte.) 2520Use this option only if the boot block reports the size incorrectly. 2521.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2522Select a non-US keyboard layout for the 2523.Em pccons 2524console driver. 2525.It Cd options CYRIX_CACHE_WORKS 2526Relevant only to the Cyrix 486DLC CPU. 2527This option is used to turn on the cache in hold-flush mode. 2528It is not turned on by default because it is known to have problems in 2529certain motherboard implementations. 2530.It Cd options CYRIX_CACHE_REALLY_WORKS 2531Relevant only to the Cyrix 486DLC CPU. 2532This option is used to turn on the cache in write-back mode. 2533It is not turned on by default because it is known to have problems in 2534certain motherboard implementations. 2535In order for this option to take effect, option 2536.Em CYRIX_CACHE_WORKS 2537must also be specified. 2538.It Cd options PCIBIOS 2539Enable support for initializing the 2540.Tn PCI 2541bus using information from the 2542.Tn BIOS . 2543See 2544.Xr pcibios 4 2545for details. 2546.It Cd options KSTACK_CHECK_DR0 2547Detect kernel stack overflow using DR0 register. 2548This option uses DR0 register exclusively so you can't use DR0 register for 2549other purpose (e.g., hardware breakpoint) if you turn this on. 2550.It Cd options MTRR 2551Include support for accessing MTRR registers from user-space. 2552See 2553.Xr i386_get_mtrr 2 . 2554.It Cd options BEEP_ONHALT 2555Make the system speaker emit several beeps when it is completely safe to 2556power down the computer after a 2557.Xr halt 8 2558command. 2559Requires 2560.Xr sysbeep 4 2561support. 2562.It Cd options BEEP_ONHALT_COUNT=times 2563Number of times to beep the speaker when 2564.Cd options BEEP_ONHALT 2565is enabled. 2566Defaults to 3. 2567.It Cd options BEEP_ONHALT_PITCH=hz 2568The tone frequency used when 2569.Cd options BEEP_ONHALT 2570option, in hertz. 2571Defaults to 1500. 2572.It Cd options BEEP_ONHALT_PERIOD=msecs 2573The duration of each beep when 2574.Cd options BEEP_ONHALT 2575is enabled, in milliseconds. 2576Defaults to 250. 2577.It Cd options MULTIBOOT 2578Makes the kernel Multiboot-compliant, allowing it to be booted through 2579a Multiboot-compliant boot manager such as GRUB. 2580See 2581.Xr multiboot 8 2582for more information. 2583.El 2584.Ss isa-specific Options 2585Options specific to 2586.Xr isa 4 2587busses. 2588.Bl -ohang 2589.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2590Control the section of IO bus space used for PCMCIA bus space mapping. 2591Ideally the probed defaults are satisfactory, however in practice 2592that is not always the case. 2593See 2594.Xr pcmcia 4 2595for details. 2596.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2597Controls the allowable interrupts that may be used for 2598.Tn PCMCIA 2599devices. 2600This mask is a logical-or of power-of-2s of allowable interrupts: 2601.Bd -literal -offset 04n 2602.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2603 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2604 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2605 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2606 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2607.Ed 2608.It Cd options PCKBC_CNATTACH_SELFTEST 2609Perform a self test of the keyboard controller before attaching it as a 2610console. 2611This might be necessary on machines where we boot on cold iron, and 2612pckbc refuses to talk until we request a self test. 2613Currently only the netwinder port uses it. 2614.It Cd options PCKBD_CNATTACH_MAY_FAIL 2615If this option is set the PS/2 keyboard will not be used as the console 2616if it cannot be found during boot. 2617This allows other keyboards, like USB, to be the console keyboard. 2618.It Cd options PCKBD_LAYOUT=layout 2619Sets the default keyboard layout, see 2620.Xr pckbd 4 . 2621.El 2622.Ss m68k-specific Options 2623.Bl -ohang 2624.It Cd options FPU_EMULATE 2625Include support for MC68881/MC68882 emulator. 2626.It Cd options FPSP 2627Include support for 68040 floating point. 2628.It Cd options M68020,M68030,M68040,M68060 2629Include support for a specific 2630.Tn CPU , 2631at least one (the one you are using) should be specified. 2632.It Cd options M060SP 2633Include software support for 68060. 2634This provides emulation of unimplemented 2635integer instructions as well as emulation of unimplemented floating point 2636instructions and data types and software support for floating point traps. 2637.El 2638.Ss powerpc-specific Options (OEA Only) 2639.Bl -ohang 2640.It Cd options PMAP_MEMLIMIT=value 2641Limit the amount of memory seen by the kernel to 2642.Ar value 2643bytes. 2644.It Cd options PTEGCOUNT=value 2645Specify the size of the page table as 2646.Ar value 2647PTE groups. 2648Normally, one PTEG is allocated per physical page frame. 2649.El 2650.Ss sparc-specific Options 2651.Bl -ohang 2652.It Cd options AUDIO_DEBUG 2653Enable simple event debugging of the logging of the 2654.Xr audio 4 2655device. 2656.It Cd options BLINK 2657Enable blinking of LED. 2658Blink rate is full cycle every N seconds for 2659N \*[Lt] then current load average. 2660See 2661.Xr getloadavg 3 . 2662.\" .It Cd options COLORFONT_CACHE 2663.\" What does this do? 2664.It Cd options COUNT_SW_LEFTOVERS 2665Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2666sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2667variables accessible from 2668.Xr ddb 4 . 2669See 2670.Xr sw 4 . 2671.It Cd options DEBUG_ALIGN 2672Adds debugging messages calls when user-requested alignment fault 2673handling happens. 2674.It Cd options DEBUG_EMUL 2675Adds debugging messages calls for emulated floating point and 2676alignment fixing operations. 2677.It Cd options DEBUG_SVR4 2678Prints registers messages calls for emulated SVR4 getcontext and 2679setcontext operations. 2680See 2681.Em options COMPAT_SVR4 . 2682.It Cd options EXTREME_DEBUG 2683Adds debugging functions callable from 2684.Xr ddb 4 . 2685The debug_pagetables, test_region and print_fe_map 2686functions print information about page tables for the SUN4M 2687platforms only. 2688.It Cd options EXTREME_EXTREME_DEBUG 2689Adds extra info to 2690.Em options EXTREME_DEBUG . 2691.It Cd options FPU_CONTEXT 2692Make 2693.Em options COMPAT_SVR4 2694getcontext and setcontext include floating point registers. 2695.It Cd options MAGMA_DEBUG 2696Adds debugging messages to the 2697.Xr magma 4 2698device. 2699.It Cd options RASTERCONS_FULLSCREEN 2700Use the entire screen for the console. 2701.It Cd options RASTERCONS_SMALLFONT 2702Use the Fixed font on the console, instead of the normal font. 2703.It Cd options SUN4 2704Support sun4 class machines. 2705.It Cd options SUN4C 2706Support sun4c class machines. 2707.It Cd options SUN4M 2708Support sun4m class machines. 2709.It Cd options SUN4_MMU3L 2710.\" XXX ??? 2711Enable support for sun4 3-level MMU machines. 2712.It Cd options V9 2713Enable SPARC V9 assembler in 2714.Xr ddb 4 . 2715.El 2716.Ss sparc64-specific Options 2717.Bl -ohang 2718.It Cd options AUDIO_DEBUG 2719Enable simple event debugging of the logging of the 2720.Xr audio 4 2721device. 2722.It Cd options BLINK 2723Enable blinking of LED. 2724Blink rate is full cycle every N seconds for 2725N \*[Lt] then current load average. 2726See 2727.Xr getloadavg 3 . 2728.El 2729.Ss x68k-specific Options 2730.Bl -ohang 2731.It Cd options EXTENDED_MEMORY 2732Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2733.It Cd options JUPITER 2734Include support for Jupiter-X MPU accelerator 2735.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2736Use the built-in serial port as the system-console. 2737Speed is specified in bps, defaults to 9600. 2738.It Cd options ITE_KERNEL_ATTR=value 2739Set the kernel message attribute for ITE. 2740Value, an integer, is a logical or of the following values: 2741.Bl -tag -width 4n -compact -offset indent 2742.It 1 2743color inversed 2744.It 2 2745underlined 2746.It 4 2747bolded 2748.El 2749.El 2750.\" The following requests should be uncommented and used where appropriate. 2751.\" .Sh FILES 2752.\" .Sh EXAMPLES 2753.Sh SEE ALSO 2754.Xr config 1 , 2755.Xr gdb 1 , 2756.Xr ktrace 1 , 2757.Xr pmc 1 , 2758.Xr quota 1 , 2759.Xr vndcompress 1 , 2760.Xr gettimeofday 2 , 2761.Xr i386_get_mtrr 2 , 2762.Xr i386_iopl 2 , 2763.Xr msgctl 2 , 2764.Xr msgget 2 , 2765.Xr msgrcv 2 , 2766.Xr msgsnd 2 , 2767.Xr ntp_adjtime 2 , 2768.Xr ntp_gettime 2 , 2769.Xr reboot 2 , 2770.Xr semctl 2 , 2771.Xr semget 2 , 2772.Xr semop 2 , 2773.Xr shmat 2 , 2774.Xr shmctl 2 , 2775.Xr shmdt 2 , 2776.Xr shmget 2 , 2777.Xr sysctl 3 , 2778.Xr apm 4 , 2779.Xr ddb 4 , 2780.Xr inet 4 , 2781.Xr iso 4 , 2782.Xr md 4 , 2783.Xr ns 4 , 2784.Xr pcibios 4 , 2785.Xr pcmcia 4 , 2786.Xr ppp 4 , 2787.Xr userconf 4 , 2788.Xr vnd 4 , 2789.Xr wscons 4 , 2790.Xr config 5 , 2791.Xr edquota 8 , 2792.Xr init 8 , 2793.Xr mdsetimage 8 , 2794.Xr mount_cd9660 8 , 2795.Xr mount_fdesc 8 , 2796.Xr mount_kernfs 8 , 2797.Xr mount_lfs 8 , 2798.Xr mount_mfs 8 , 2799.Xr mount_msdos 8 , 2800.Xr mount_nfs 8 , 2801.Xr mount_ntfs 8 , 2802.Xr mount_null 8 , 2803.Xr mount_portal 8 , 2804.Xr mount_procfs 8 , 2805.Xr mount_udf 8 , 2806.Xr mount_umap 8 , 2807.Xr mount_union 8 , 2808.Xr mrouted 8 , 2809.Xr newfs_lfs 8 , 2810.Xr ntpd 8 , 2811.Xr quotaon 8 , 2812.Xr rpc.rquotad 8 , 2813.Xr sysctl 8 , 2814.Xr in_getifa 9 2815.Sh HISTORY 2816The 2817.Nm 2818man page first appeared in 2819.Nx 1.3 . 2820.Sh BUGS 2821The 2822.Em EON 2823option should be a pseudo-device, and is also very fragile. 2824