1.\" $NetBSD: options.4,v 1.389 2010/05/01 13:07:34 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 May 1, 2010 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 ext2 Pc , 692revision 0 and revision 1 with the 693.Em filetype , 694.Em sparse_super 695and 696.Em large_file 697options. 698This is the most commonly used file system on the Linux operating system, 699and is provided here for compatibility. 700Some of the specific features of 701.Em ext2 702like the "behavior on errors" are not implemented. 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 903Includes kernel support for the pass-to-userspace framework file system. 904It can be used to implement file system functionality in userspace. 905See 906.Xr puffs 3 907for more details. 908This enables for example sshfs: 909.Xr mount_psshfs 8 . 910.El 911.Ss File System Options 912.Bl -ohang 913.It Cd options MAGICLINKS 914Enables the expansion of special strings 915.Po 916beginning with 917.Dq @ 918.Pc 919when traversing symbolic links. 920See 921.Xr symlink 7 922for a list of supported strings. 923Note that this option only controls the enabling of this feature 924by the kernel at boot-up. 925This feature can still be manipulated with the 926.Xr sysctl 8 927command regardless of the setting of this option. 928.It Cd options NFSSERVER 929Include the server side of the 930.Em NFS 931(Network File System) remote file sharing protocol. 932Although the bulk of the code implementing 933.Em NFS 934is kernel based, several user level daemons are needed for it to 935work. 936See 937.Xr mountd 8 938and 939.Xr nfsd 8 940for details. 941.It Cd options QUOTA 942Enables kernel support for file system quotas. 943See 944.Xr quotaon 8 , 945.Xr edquota 8 , 946and 947.Xr quota 1 948for details. 949Note that quotas only work on 950.Dq ffs 951file systems, although 952.Xr rpc.rquotad 8 953permits them to be accessed over 954.Em NFS . 955.It Cd options FFS_EI 956Enable ``Endian-Independent'' FFS support. 957This allows a system to mount an FFS file system created for another 958architecture, at a small performance cost for all FFS file systems. 959See also 960.Xr newfs 8 , 961.Xr fsck_ffs 8 , 962.Xr dumpfs 8 963for file system byte order status and manipulation. 964.It Cd options FFS_NO_SNAPSHOT 965Disable the 966.Dq file system snapshot 967support in FFS file systems. 968Maybe useful for install media kernels, small memory systems and 969embedded systems which don't require the snapshot support. 970.It Cd options WAPBL 971Enable 972.Dq Write Ahead Physical Block Logging file system journaling . 973This provides rapid file system consistency checking after a system outage. 974It also provides better general use performance over regular FFS. 975See also 976.Xr wapbl 4 . 977.It Cd options NVNODE=integer 978This option sets the size of the cache used by the name-to-inode translation 979routines, (a.k.a. the 980.Fn namei 981cache, though called by many other names in the kernel source). 982By default, this cache has 983.Dv NPROC 984(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 985A reasonable way to derive a value of 986.Dv NVNODE , 987should you notice a large number of namei cache misses with a tool such as 988.Xr systat 1 , 989is to examine your system's current computed value with 990.Xr sysctl 8 , 991(which calls this parameter "kern.maxvnodes") and to increase this value 992until either the namei cache hit rate improves or it is determined that 993your system does not benefit substantially from an increase in the size of 994the namei cache. 995.It Cd options NAMECACHE_ENTER_REVERSE 996Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 997as well as a normal one. 998Normally, this is already done for directory vnodes, to speed up the getcwd 999operation. 1000This option will cause longer hash chains in the reverse cache, and thus 1001slow down getcwd somewhat. 1002However, it does make vnode -\*[Gt] path translations possible in some cases. 1003For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1004required. 1005.It Cd options EXT2FS_SYSTEM_FLAGS 1006This option changes the behavior of the APPEND and IMMUTABLE flags 1007for a file on an 1008.Em ext2 1009file system. 1010Without this option, the superuser or owner of the file can 1011set and clear them. 1012With this option, only the superuser can set them, and 1013they can't be cleared if the securelevel is greater than 0. 1014See also 1015.Xr chflags 1 1016and 1017.Xr secmodel_securelevel 9 . 1018.It Cd options NFS_BOOT_BOOTP 1019Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1020information if NFS is used to mount the root file system. 1021See 1022.Xr diskless 8 1023for details. 1024.It Cd options NFS_BOOT_DHCP 1025Same as 1026.Dq NFS_BOOT_BOOTP , 1027but use the DHCP extensions to the 1028BOOTP protocol (RFC 1541). 1029.It Cd options NFS_BOOT_BOOTP_REQFILE 1030Specifies the string sent in the bp_file field of the BOOTP / DHCP 1031request packet. 1032.It Cd options NFS_BOOT_BOOTPARAM 1033Enable use of the BOOTPARAM protocol, consisting of RARP and 1034BOOTPARAM RPC, to get configuration information if NFS 1035is used to mount the root file system. 1036See 1037.Xr diskless 8 1038for details. 1039.It Cd options NFS_BOOT_RWSIZE=value 1040Set the initial NFS read and write sizes for diskless-boot requests. 1041The normal default is 8Kbytes. 1042This option provides a way to lower the value (e.g., to 1024 bytes) 1043as a workaround for buggy network interface cards or boot PROMs. 1044Once booted, the read and write request sizes can be increased by 1045remounting the file system. 1046See 1047.Xr mount_nfs 8 1048for details. 1049.It Cd options NFS_V2_ONLY 1050Reduce the size of the NFS client code by omitting code that's only required 1051for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1052servers. 1053.It Cd options UFS_DIRHASH 1054Increase lookup performance by maintaining in-core hash tables 1055for large directories. 1056.El 1057.Ss Buffer queue strategy options 1058The following options enable alternative buffer queue strategies. 1059.Bl -ohang 1060.It Cd options BUFQ_READPRIO 1061Enable experimental buffer queue strategy for disk I/O. 1062In the default strategy, outstanding disk requests are ordered by 1063sector number and sent to the disk, regardless of whether the 1064operation is a read or write; this option gives priority to issuing 1065read requests over write requests. 1066Although requests may therefore be issued out of sector-order, causing 1067more seeks and thus lower overall throughput, interactive system 1068responsiveness under heavy disk I/O load may be improved, as processes 1069blocking on disk reads are serviced sooner (file writes typically 1070don't cause applications to block). 1071The performance effect varies greatly depending on the hardware, drive 1072firmware, file system configuration, workload, and desired performance 1073trade-off. 1074Systems using drive write-cache (most modern IDE disks, by default) 1075are unlikely to benefit and may well suffer; such disks acknowledge 1076writes very quickly, and optimize them internally according to 1077physical layout. 1078Giving these disks as many requests to work with as possible (the 1079standard strategy) will typically produce the best results, especially 1080if the drive has a large cache; the drive will silently complete 1081writes from cache as it seeks for reads. 1082Disks that support a large number of concurrent tagged requests (SCSI 1083disks and many hardware RAID controllers) expose this internal 1084scheduling with tagged responses, and don't block for reads; such 1085disks may not see a noticeable difference with either strategy. 1086However, if IDE disks are run with write-cache disabled for safety, 1087writes are not acknowledged until actually completed, and only one 1088request can be outstanding; a large number of small writes in one 1089locality can keep the disk busy, starving reads elsewhere on the disk. 1090Such systems are likely to see the most benefit from this option. 1091Finally, the performance interaction of this option with ffs soft 1092dependencies can be subtle, as that mechanism can drastically alter 1093the workload for file system metadata writes. 1094.It Cd options BUFQ_PRIOCSCAN 1095Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1096.It Cd options NEW_BUFQ_STRATEGY 1097Synonym of 1098.Em BUFQ_READPRIO . 1099.El 1100.Ss Miscellaneous Options 1101.Bl -ohang 1102.It Cd options MEMORY_DISK_DYNAMIC 1103This option makes the 1104.Xr md 4 1105.Tn RAM 1106disk size dynamically sized. 1107It is incompatible with 1108.Xr mdsetimage 8 . 1109.It Cd options MEMORY_DISK_HOOKS 1110This option allows for some machine dependent functions to be called when 1111the 1112.Xr md 4 1113.Tn RAM 1114disk driver is configured. 1115This can result in automatically loading a 1116.Tn RAM 1117disk from floppy on open (among other things). 1118.It Cd options MEMORY_DISK_IS_ROOT 1119Forces the 1120.Xr md 4 1121.Tn RAM 1122disk to be the root device. 1123This can only be overridden when 1124the kernel is booted in the 'ask-for-root' mode. 1125.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1126Allocates the given number of 512 byte blocks as memory for the 1127.Xr md 4 1128.Tn RAM 1129disk, to be populated with 1130.Xr mdsetimage 8 . 1131.It Cd options MEMORY_DISK_SERVER=0 1132Do not include the interface to a userland memory disk server process. 1133Per default, this option is set to 1, including the support code. 1134Useful for install media kernels. 1135.It Cd options MEMORY_DISK_RBFLAGS=value 1136This option sets the 1137.Xr reboot 2 1138flags used when booting with a memory disk as root file system. 1139Possible values include 1140.Dv RB_AUTOBOOT 1141(boot in the usual fashion - default value), and 1142.Dv RB_SINGLE 1143(boot in single-user mode). 1144.It Cd options MODULAR 1145Enables the framework for kernel modules. 1146.It Cd options VND_COMPRESSION 1147Enables the 1148.Xr vnd 4 1149driver to also handle compressed images. 1150See 1151.Xr vndcompress 1 , 1152.Xr vnd 4 1153and 1154.Xr vnconfig 8 1155for more information. 1156.It Cd options SPLDEBUG 1157Help the kernel programmer find bugs related to the interrupt priority 1158level. 1159When 1160.Fn spllower 1161or 1162.Fn splraise 1163changes the current CPU's interrupt priority level to or from 1164.Dv IPL_HIGH , 1165record a backtrace. 1166Read 1167.Xr return_address 9 1168for caveats about collecting backtraces. 1169This feature is experimental, and it is only available on i386. 1170See 1171.Pa sys/kern/subr_spldebug.c . 1172.It Cd options TFTPROOT 1173Download the root memory disk through TFTP at root mount time. 1174This enables the use of a root 1175.Tn RAM 1176disk without requiring it to be embedded in the kernel using 1177.Xr mdsetimage 8 . 1178The 1179.Tn RAM 1180disk name is obtained using DHCP's filename parameter. 1181This option requires 1182.Em MEMORY_DISK_HOOKS , 1183.Em MEMORY_DISK_DYNAMIC , 1184and 1185.Em MEMORY_DISK_IS_ROOT . 1186It is incompatible with 1187.Em MEMORY_DISK_ROOT_SIZE . 1188.It Cd options MALLOC_NOINLINE 1189Time critical fixed size memory allocation is performed with 1190.Fn MALLOC 1191and 1192.Fn FREE . 1193Normally these expand to inline code, but with 1194.Em MALLOC_NOINLINE 1195these call the normal 1196.Fn malloc 1197and 1198.Fn free 1199functions. 1200Useful for install media kernels, small memory systems and embedded systems. 1201.It Cd options HZ=integer 1202On ports that support it, set the system clock frequency (see 1203.Xr hz 9 ) 1204to the supplied value. 1205Handle with care. 1206.It Cd options NTP 1207Turns on in-kernel precision timekeeping support used by software 1208implementing 1209.Em NTP 1210(Network Time Protocol, RFC 1305). 1211The 1212.Em NTP 1213option adds an in-kernel Phase-Locked Loop (PLL) for normal 1214.Em NTP 1215operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1216operation. 1217.Xr ntpd 8 1218will employ a user-level PLL when kernel support is unavailable, 1219but the in-kernel version has lower latency and more precision, and 1220so typically keeps much better time. 1221The interface to the kernel 1222.Em NTP 1223support is provided by the 1224.Xr ntp_adjtime 2 1225and 1226.Xr ntp_gettime 2 1227system calls, which are intended for use by 1228.Xr ntpd 8 1229and are enabled by the option. 1230On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1231is not an integer, the 1232.Em NTP 1233option also enables extended-precision arithmetic to keep track of 1234fractional clock ticks at NTP time-format precision. 1235.It Cd options PPS_SYNC 1236This option enables a kernel serial line discipline for receiving time 1237phase signals from an external reference clock such as a radio clock. 1238(The 1239.Em NTP 1240option (which see) must be on if the 1241.Em PPS_SYNC 1242option is used.) 1243Some reference clocks generate a Pulse Per Second (PPS) signal in 1244phase with their time source. 1245The 1246.Em PPS 1247line discipline receives this signal on either the data leads 1248or the DCD control lead of a serial port. 1249.Em NTP 1250uses the PPS signal to discipline the local clock oscillator to a high 1251degree of precision (typically less than 50 microseconds in time and 12520.1 ppm in accuracy). 1253.Em PPS 1254can also generate a serial output pulse when the system receives a PPS 1255interrupt. 1256This can be used to measure the system interrupt latency and thus calibrate 1257.Em NTP 1258to account for it. 1259Using 1260.Em PPS 1261usually requires a 1262gadget box 1263to convert from TTL to RS-232 signal levels. 1264The gadget box and PPS are described in more detail in the HTML documentation 1265for 1266.Xr ntpd 8 1267in 1268.Pa /usr/share/doc/html/ntp . 1269.It Cd options SETUIDSCRIPTS 1270Allows scripts with the setuid bit set to execute as the effective 1271user rather than the real user, just like binary executables. 1272.Pp 1273.Em NOTE : 1274Using this option will also enable 1275.Em options FDSCRIPTS 1276.It Cd options FDSCRIPTS 1277Allows execution of scripts with the execute bit set, but not the 1278read bit, by opening the file and passing the file descriptor to 1279the shell, rather than the filename. 1280.Pp 1281.Em NOTE : 1282Execute only (non-readable) scripts will have 1283.Va argv[0] 1284set to 1285.Pa /dev/fd/* . 1286What this option allows as far as security is 1287concerned, is the ability to safely ensure that the correct script 1288is run by the interpreter, as it is passed as an already open file. 1289.It Cd options PUCCN 1290Enables treating serial ports found on PCI boards 1291.Xr puc 4 1292as potential console devices. 1293The method for choosing such a console device is port dependent. 1294.It Cd options RTC_OFFSET=integer 1295The kernel (and typically the hardware battery backed-up clock on 1296those machines that have one) keeps time in 1297.Em UTC 1298(Universal Coordinated Time, once known as 1299.Em GMT , 1300or Greenwich Mean Time) 1301and not in the time of the local time zone. 1302The 1303.Em RTC_OFFSET 1304option is used on some ports (such as the i386) to tell the kernel 1305that the hardware clock is offset from 1306.Em UTC 1307by the specified number of minutes. 1308This is typically used when a machine boots several operating 1309systems and one of them wants the hardware clock to run in the 1310local time zone and not in 1311.Em UTC , 1312e.g. 1313.Em RTC_OFFSET=300 1314means 1315the hardware clock is set to US Eastern Time (300 minutes behind 1316.Em UTC ) , 1317and not 1318.Em UTC . 1319(Note: 1320.Em RTC_OFFSET 1321is used to initialize a kernel variable named 1322.Va rtc_offset 1323which is the source actually used to determine the clock offset, and 1324which may be accessed via the kern.rtc_offset sysctl variable. 1325See 1326.Xr sysctl 8 1327and 1328.Xr sysctl 3 1329for details. 1330Since the kernel clock is initialized from the hardware clock very 1331early in the boot process, it is not possible to meaningfully change 1332.Va rtc_offset 1333in system initialization scripts. 1334Changing this value currently may only be done at kernel compile 1335time or by patching the kernel and rebooting). 1336.Pp 1337.Em NOTE : 1338Unfortunately, in many cases where the hardware clock 1339is kept in local time, it is adjusted for Daylight Savings 1340Time; this means that attempting to use 1341.Em RTC_OFFSET 1342to let 1343.Nx 1344coexist with such an operating system, like Windows, 1345would necessitate changing 1346.Em RTC_OFFSET 1347twice a year. 1348As such, this solution is imperfect. 1349.It Cd options KMEMSTATS 1350The kernel memory allocator, 1351.Xr malloc 9 , 1352will keep statistics on its performance if this option is enabled. 1353Unfortunately, this option therefore essentially disables the 1354.Fn MALLOC 1355and 1356.Fn FREE 1357forms of the memory allocator, which are used to enhance the performance 1358of certain critical sections of code in the kernel. 1359This option therefore can lead to a significant decrease in the 1360performance of certain code in the kernel if enabled. 1361Examples of such code include the 1362.Fn namei 1363routine, the 1364.Xr ccd 4 1365driver, 1366and much of the networking code. 1367.It Cd options MAXUPRC=integer 1368Sets the soft 1369.Dv RLIMIT_NPROC 1370resource limit, which specifies the maximum number of simultaneous 1371processes a user is permitted to run, for process 0; 1372this value is inherited by its child processes. 1373It defaults to 1374.Em CHILD_MAX , 1375which is currently defined to be 160. 1376Setting 1377.Em MAXUPRC 1378to a value less than 1379.Em CHILD_MAX 1380is not permitted, as this would result in a violation of the semantics of 1381.St -p1003.1-90 . 1382.It Cd options NOFILE=integer 1383Sets the soft 1384.Dv RLIMIT_NOFILE 1385resource limit, which specifies the maximum number of open 1386file descriptors for each process; 1387this value is inherited by its child processes. 1388It defaults to 1389.Em OPEN_MAX , 1390which is currently defined to be 64. 1391.It Cd options MAXFILES=integer 1392Sets the default value of the 1393.Em kern.maxfiles 1394sysctl variable, which indicates the maximum number of files that may 1395be open in the system. 1396.It Cd options DEFCORENAME=string 1397Sets the default value of the 1398.Em kern.defcorename 1399sysctl variable, otherwise it is set to 1400.Nm %n.core . 1401See 1402.Xr sysctl 8 1403and 1404.Xr sysctl 3 1405for details. 1406.It Cd options RASOPS_CLIPPING 1407Enables clipping within the 1408.Nm rasops 1409raster-console output system. 1410.Em NOTE : 1411only available on architectures that use 1412.Nm rasops 1413for console output. 1414.It Cd options RASOPS_SMALL 1415Removes optimized character writing code from the 1416.Nm rasops 1417raster-console output system. 1418.Em NOTE : 1419only available on architectures that use 1420.Nm rasops 1421for console output. 1422.It Cd options INCLUDE_CONFIG_FILE 1423Embeds the kernel config file used to define the kernel in the kernel 1424binary itself. 1425The embedded data also includes any files directly included by the config 1426file itself, e.g. 1427.Pa GENERIC.local 1428or 1429.Pa std.$MACHINE . 1430The embedded config file can be extracted from the resulting kernel with 1431.Xr config 1 1432.Fl x , 1433or by the following command: 1434.Bd -literal -offset indent 1435strings netbsd | sed -n 's/^_CFG_//p' | unvis 1436.Ed 1437.It Cd options INCLUDE_JUST_CONFIG 1438Similar to the above option, but includes just the actual config file, 1439not any included files. 1440.It Cd options PIPE_SOCKETPAIR 1441Use slower, but smaller socketpair(2)-based pipe implementation instead 1442of default faster, but bigger one. 1443Primarily useful for installation kernels. 1444.It Cd options USERCONF 1445Compiles in the in-kernel device configuration manager. 1446See 1447.Xr userconf 4 1448for details. 1449.It Cd options PERFCTRS 1450Compiles in kernel support for CPU performance-monitoring counters. 1451See 1452.Xr pmc 1 1453for details. 1454.Em NOTE : 1455not available on all architectures. 1456.It Cd options SYSCALL_STATS 1457Count the number of times each system call number is called. 1458The values can be read through the sysctl interface and displayed using 1459.Xr systat 1 . 1460.Em NOTE : 1461not yet available on all architectures. 1462.It Cd options SYSCALL_TIMES 1463Count the time spent (using 1464.Fn cpu_counter32 ) 1465in each system call. 1466.Em NOTE : 1467Using this option will also enable 1468.Cd options SYSCALL_STATS . 1469.It Cd options SYSCALL_TIMES_HASCOUNTER 1470Force use of 1471.Fn cpu_counter32 1472even if 1473.Fn cpu_hascounter 1474reports false. 1475Useful for systems where the cycle counter doesn't run at a constant rate 1476(e.g. Soekris boxes). 1477.It Cd options XSERVER 1478Compiles in kernel support for 1479.Tn X11 1480on architectures that still use (or can use) the legacy 1481.Em pccons 1482console drivers rather than 1483.Xr wscons 4 . 1484These include bebox, i386, shark. 1485.It Cd options XSERVER_DDB 1486A supplement to XSERVER that adds support for entering 1487.Xr ddb 4 1488while in 1489.Tn X11 . 1490.It Cd options FILEASSOC 1491Support for 1492.Xr fileassoc 9 . 1493.It Cd options FILEASSOC_NHOOKS=integer 1494Number of storage slots per file for 1495.Xr fileassoc 9 . 1496Default is 4. 1497.It Cd options I2C_SCAN 1498Scan each i2c bus to determine which addresses respond. 1499.Pp 1500.Em WARNING ! 1501Using this option can access some devices in such a 1502manner as to leave them in an unstable or unuseable state, and 1503can prevent those devices from being properly matched and/or 1504attached. 1505It can also lock up the entire i2c bus and even 1506prevent a machine from completing the boot process. 1507Don't use this option unless you know what you're doing and can 1508accept all sorts of unforeseen consequences. 1509.El 1510.Ss Networking Options 1511.Bl -ohang 1512.It Cd options GATEWAY 1513Enables 1514.Em IPFORWARDING 1515(which see) 1516and (on most ports) increases the size of 1517.Em NMBCLUSTERS 1518(which see). 1519In general, 1520.Em GATEWAY 1521is used to indicate that a system should act as a router, and 1522.Em IPFORWARDING 1523is not invoked directly. 1524(Note that 1525.Em GATEWAY 1526has no impact on protocols other than 1527.Tn IP , 1528such as 1529.Tn CLNP 1530or 1531.Tn XNS ) . 1532.Em GATEWAY 1533option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1534.It Cd options ICMPPRINTFS 1535The 1536.Em ICMPPRINTFS 1537option will enable debugging information to be printed about 1538the 1539.Xr icmp 4 1540protocol. 1541.It Cd options IPFORWARDING=value 1542If 1543.Em value 1544is 1 this enables IP routing behavior. 1545If 1546.Em value 1547is 0 (the default), it disables it. 1548The 1549.Em GATEWAY 1550option sets this to 1 automatically. 1551With this option enabled, the machine will forward IP datagrams destined 1552for other machines between its interfaces. 1553Note that even without this option, the kernel will 1554still forward some packets (such as source routed packets) -- removing 1555.Em GATEWAY 1556and 1557.Em IPFORWARDING 1558is insufficient to stop all routing through a bastion host on a 1559firewall -- source routing is controlled independently. 1560To turn off source routing, use 1561.Em options IPFORWSRCRT=0 1562(which see). 1563Note that IP forwarding may be turned on and off independently of the 1564setting of the 1565.Em IPFORWARDING 1566option through the use of the 1567.Em net.inet.ip.forwarding 1568sysctl variable. 1569If 1570.Em net.inet.ip.forwarding 1571is 1, IP forwarding is on. 1572See 1573.Xr sysctl 8 1574and 1575.Xr sysctl 3 1576for details. 1577.It Cd options IPFORWSRCRT=value 1578If 1579.Em value 1580is set to zero, source routing of IP datagrams is turned off. 1581If 1582.Em value 1583is set to one (the default) or the option is absent, source routed IP 1584datagrams are forwarded by the machine. 1585Note that source routing of IP packets may be turned on and off 1586independently of the setting of the 1587.Em IPFORWSRCRT 1588option through the use of the 1589.Em net.inet.ip.forwsrcrt 1590sysctl variable. 1591If 1592.Em net.inet.ip.forwsrcrt 1593is 1, forwarding of source routed IP datagrams is on. 1594See 1595.Xr sysctl 8 1596and 1597.Xr sysctl 3 1598for details. 1599.It Cd options IFA_STATS 1600Tells the kernel to maintain per-address statistics on bytes sent 1601and received over (currently) Internet and AppleTalk addresses. 1602.\"This can be a fairly expensive operation, so you probably want to 1603.\"keep this disabled. 1604The option is not recommended as it degrades system stability. 1605.It Cd options IFQ_MAXLEN=value 1606Increases the allowed size of the network interface packet queues. 1607The default queue size is 50 packets, and you do not normally need 1608to increase it. 1609.It Cd options IPSELSRC 1610Includes support for source-address selection policies. 1611See 1612.Xr in_getifa 9 . 1613.It Cd options MROUTING 1614Includes support for IP multicast routers. 1615You certainly want 1616.Em INET 1617with this. 1618Multicast routing is controlled by the 1619.Xr mrouted 8 1620daemon. 1621See also option 1622.Cd PIM . 1623.It Cd options PIM 1624Includes support for Protocol Independent Multicast (PIM) routing. 1625You need 1626.Em MROUTING 1627and 1628.Em INET 1629with this. 1630Software using this can be found e.g. in 1631.Pa pkgsrc/net/xorp . 1632.It Cd options INET 1633Includes support for the 1634.Tn TCP/IP 1635protocol stack. 1636You almost certainly want this. 1637See 1638.Xr inet 4 1639for details. 1640.It Cd options INET6 1641Includes support for the 1642.Tn IPv6 1643protocol stack. 1644See 1645.Xr inet6 4 1646for details. 1647Unlike 1648.Em INET , 1649.Em INET6 1650enables multicast routing code as well. 1651This option requires 1652.Em INET 1653at this moment, but it should not. 1654.It Cd options ND6_DEBUG 1655The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1656for debugging IPv6 neighbor discovery protocol handling. 1657See 1658.Xr sysctl 3 1659for details. 1660.It Cd options IPSEC 1661Includes support for the 1662.Tn IPsec 1663protocol. 1664See 1665.Xr ipsec 4 1666for details. 1667.It Cd options IPSEC_DEBUG 1668Enables debugging code in 1669.Tn IPsec 1670stack. 1671See 1672.Xr ipsec 4 1673for details. 1674.It Cd options IPSEC_ESP 1675Includes support for 1676.Tn IPsec 1677.Tn ESP 1678protocol. 1679See 1680.Xr ipsec 4 1681for details. 1682.It Cd options IPSEC_NAT_T 1683Includes support for 1684.Tn IPsec 1685Network Address Translator traversal (NAT-T), as described in RFCs 3947 1686and 3948. 1687This feature might be patent-encumbered in some countries. 1688.It Cd options ALTQ 1689Enabled ALTQ (Alternate Queueing). 1690For simple rate-limiting, use 1691.Xr tbrconfig 8 1692to set up the interface transmission rate. 1693To use queueing disciplines, their appropriate kernel options should also 1694be defined (documented below). 1695Queueing disciplines are managed by 1696.Xr altqd 8 . 1697See 1698.Xr altq 9 1699for details. 1700.It Cd options ALTQ_HFSC 1701Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1702module. 1703HFSC supports both link-sharing and guaranteed real-time services. 1704HFSC employs a service curve based QoS model, and its unique feature 1705is an ability to decouple delay and bandwidth allocation. 1706Requires 1707.Em ALTQ_RED 1708to use the RED queueing discipline on HFSC classes, or 1709.Em ALTQ_RIO 1710to use the RIO queueing discipline on HFSC classes. 1711This option assumes 1712.Em ALTQ . 1713.It Cd options ALTQ_PRIQ 1714Include support for ALTQ-implemented PRIQ (Priority Queueing). 1715PRIQ implements a simple priority-based queueing discipline. 1716A higher priority class is always served first. 1717Requires 1718.Em ALTQ_RED 1719to use the RED queueing discipline on HFSC classes, or 1720.Em ALTQ_RIO 1721to use the RIO queueing discipline on HFSC classes. 1722This option assumes 1723.Em ALTQ . 1724.It Cd options ALTQ_WFQ 1725Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1726WFQ implements a weighted-round robin scheduler for a set of queues. 1727A weight can be assigned to each queue to give a different proportion 1728of the link capacity. 1729A hash function is used to map a flow to one of a set of queues. 1730This option assumes 1731.Em ALTQ . 1732.It Cd options ALTQ_FIFOQ 1733Include support for ALTQ-implemented FIFO queueing. 1734FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1735This option assumes 1736.Em ALTQ . 1737.It Cd options ALTQ_RIO 1738Include support for ALTQ-implemented RIO (RED with In/Out). 1739The original RIO has 2 sets of RED parameters; one for in-profile 1740packets and the other for out-of-profile packets. 1741At the ingress of the network, profile meters tag packets as IN or 1742OUT based on contracted profiles for customers. 1743Inside the network, IN packets receive preferential treatment by 1744the RIO dropper. 1745ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1746PHB of DiffServ (RFC 2597). 1747This option assumes 1748.Em ALTQ . 1749.It Cd options ALTQ_BLUE 1750Include support for ALTQ-implemented Blue buffer management. 1751Blue is another active buffer management mechanism. 1752This option assumes 1753.Em ALTQ . 1754.It Cd options ALTQ_FLOWVALVE 1755Include support for ALTQ-implemented Flowvalve. 1756Flowvalve is a simple implementation of a RED penalty box that identifies 1757and punishes misbehaving flows. 1758This option requires 1759.Em ALTQ_RED 1760and assumes 1761.Em ALTQ . 1762.It Cd options ALTQ_CDNR 1763Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1764packet marking/manipulation. 1765Traffic conditioners are components to meter, mark, or drop incoming 1766packets according to some rules. 1767As opposed to queueing disciplines, traffic conditioners handle incoming 1768packets at an input interface. 1769This option assumes 1770.Em ALTQ . 1771.It Cd options ALTQ_NOPCC 1772Disables use of processor cycle counter to measure time in ALTQ. 1773This option should be defined for a non-Pentium i386 CPU which does not 1774have TSC, SMP (per-CPU counters are not in sync), or power management 1775which affects processor cycle counter. 1776This option assumes 1777.Em ALTQ . 1778.It Cd options ALTQ_IPSEC 1779Include support for IPsec in IPv4 ALTQ. 1780This option assumes 1781.Em ALTQ . 1782.It Cd options ALTQ_JOBS 1783Include support for ALTQ-implemented JoBS (Joint Buffer Management 1784and Scheduling). 1785This option assumes 1786.Em ALTQ . 1787.It Cd options ALTQ_AFMAP 1788Include support for an undocumented ALTQ feature that is used to map an IP 1789flow to an ATM VC (Virtual Circuit). 1790This option assumes 1791.Em ALTQ . 1792.It Cd options ALTQ_LOCALQ 1793Include support for ALTQ-implemented local queues. 1794Its practical use is undefined. 1795Assumes 1796.Em ALTQ . 1797.It Cd options SUBNETSARELOCAL 1798Sets default value for net.inet.ip.subnetsarelocal variable, which 1799controls whether non-directly-connected subnets of connected networks 1800are considered "local" for purposes of choosing the MSS for a TCP 1801connection. 1802This is mostly present for historic reasons and completely irrelevant if 1803you enable Path MTU discovery. 1804.It Cd options HOSTZEROBROADCAST 1805Sets default value for net.inet.ip.hostzerobroadcast variable, which 1806controls whether the zeroth host address of each connected subnet is 1807also considered a broadcast address. 1808Default value is "1", for compatibility with old systems; if this is 1809set to zero on all hosts on a subnet, you should be able to fit an extra 1810host per subnet on the 1811".0" address. 1812.It Cd options MCLSHIFT=value 1813This option is the base-2 logarithm of the size of mbuf clusters. 1814The 1815.Bx 1816networking stack keeps network packets in a linked 1817list, or chain, of kernel buffer objects called mbufs. 1818The system provides larger mbuf clusters as an optimization for 1819large packets, instead of using long chains for large packets. 1820The mbuf cluster size, 1821or 1822.Em MCLBYTES , 1823must be a power of two, and is computed as two raised to the power 1824.Em MCLSHIFT . 1825On systems with Ethernet network adapters, 1826.Em MCLSHIFT 1827is often set to 11, giving 2048-byte mbuf clusters, large enough to 1828hold a 1500-byte 1829.Tn Ethernet 1830frame in a single cluster. 1831Systems with network interfaces supporting larger frame sizes like 1832.Tn ATM , 1833.Tn FDDI , 1834or 1835.Tn HIPPI 1836may perform better with 1837.Em MCLSHIFT 1838set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1839respectively. 1840.It Cd options NS 1841Include support for the 1842.Tn Xerox 1843.Tn XNS 1844protocol stack. 1845See 1846.Xr ns 4 1847for details. 1848.It Cd options ISO,TPIP 1849Include support for the ubiquitous 1850.Tn OSI 1851protocol stack. 1852See 1853.Xr iso 4 1854for details. 1855This option assumes 1856.Em INET . 1857.It Cd options EON 1858Include support for tunneling 1859.Tn OSI 1860protocols over 1861.Tn IP . 1862Known to be broken, or at least very fragile, and undocumented. 1863.It Cd options NETATALK 1864Include support for the 1865.Tn AppleTalk 1866protocol stack. 1867The kernel provides provision for the 1868.Em Datagram Delivery Protocol 1869(DDP), providing SOCK_DGRAM support and 1870.Tn AppleTalk 1871routing. 1872This stack is used by the 1873.Em NETATALK 1874package, which adds support for 1875.Tn AppleTalk 1876server services via user libraries and applications. 1877.It Cd options BLUETOOTH 1878Include support for the 1879.Tn Bluetooth 1880protocol stack. 1881See 1882.Xr bluetooth 4 1883for details. 1884.It Cd options IPNOPRIVPORTS 1885Normally, only root can bind a socket descriptor to a so-called 1886.Dq privileged 1887.Tn TCP 1888port, that is, a port number in the range 0-1023. 1889This option eliminates those checks from the kernel. 1890This can be useful if there is a desire to allow daemons without 1891privileges to bind those ports, e.g., on firewalls. 1892The security tradeoffs in doing this are subtle. 1893This option should only be used by experts. 1894.It Cd options TCP_COMPAT_42 1895.Tn TCP 1896bug compatibility with 1897.Bx 4.2 . 1898In 1899.Bx 4.2 , 1900.Tn TCP 1901sequence numbers were 32-bit signed values. 1902Modern implementations of TCP use unsigned values. 1903This option clamps the initial sequence number to start in 1904the range 2^31 rather than the full unsigned range of 2^32. 1905Also, under 1906.Bx 4.2 , 1907keepalive packets must contain at least one byte or else 1908the remote end would not respond. 1909.It Cd options TCP_DEBUG 1910Record the last 1911.Em TCP_NDEBUG 1912TCP packets with SO_DEBUG set, and decode to the console if 1913.Em tcpconsdebug 1914is set. 1915.It Cd options TCP_NDEBUG 1916Number of packets to record for 1917.Em TCP_DEBUG . 1918Defaults to 100. 1919.It Cd options TCP_SENDSPACE=value 1920.It Cd options TCP_RECVSPACE=value 1921These options set the max TCP window size to other sizes than the default. 1922The TCP window sizes can be altered via 1923.Xr sysctl 8 1924as well. 1925.It Cd options TCP_INIT_WIN=value 1926This option sets the initial TCP window size for non-local connections, 1927which is used when the transmission starts. 1928The default size is 1, but if the machine should act more aggressively, 1929the initial size can be set to some other value. 1930The initial TCP window size can be set via 1931.Xr sysctl 8 1932as well. 1933.It Cd options PFIL_HOOKS 1934This option turns on the packet filter interface hooks. 1935See 1936.Xr pfil 9 1937for details. 1938This option assumes 1939.Em INET . 1940.It Cd options IPFILTER_LOG 1941This option, in conjunction with 1942.Em pseudo-device ipfilter , 1943enables logging of IP packets using ip-filter. 1944.It Cd options IPFILTER_DEFAULT_BLOCK 1945This option sets the default policy of ip-filter. 1946If it is set, ip-filter will block packets by default. 1947.It Cd options BRIDGE_IPF 1948This option causes 1949.Em bridge 1950devices to use the IP and/or IPv6 filtering hooks, forming 1951a link-layer filter that uses protocol-layer rules. 1952This option assumes the presence of 1953.Em pseudo-device ipfilter . 1954.It Cd options MBUFTRACE 1955This option can help track down mbuf leaks. 1956When enabled, mbufs are tagged with the devices and protocols using them, 1957which slightly decreases network performance. 1958This additional information can be viewed with 1959.Xr netstat 1 : 1960.Dl Ic netstat Fl mssv 1961Not all devices or protocols support this option. 1962.El 1963.Ss Sysctl Related Options 1964.Bl -ohang 1965.It Cd options SYSCTL_DISALLOW_CREATE 1966Disallows the creation or deletion of nodes from the sysctl tree, as 1967well as the assigning of descriptions to nodes that lack them, by any 1968process. 1969These operations are still available to kernel sub-systems, including 1970loadable kernel modules. 1971.It Cd options SYSCTL_DISALLOW_KWRITE 1972Prevents processes from adding nodes to the sysctl tree that make 1973existing kernel memory areas writable. 1974Sections of kernel memory can still be read and new nodes that own 1975their own data may still be writable. 1976.It Cd options SYSCTL_DEBUG_SETUP 1977Causes the SYSCTL_SETUP routines to print a brief message when they 1978are invoked. 1979This is merely meant as an aid in determining the order in which 1980sections of the tree are created. 1981.It Cd options SYSCTL_DEBUG_CREATE 1982Prints a message each time 1983.Fn sysctl_create , 1984the function that adds nodes to the tree, is called. 1985.It Cd options SYSCTL_INCLUDE_DESCR 1986Causes the kernel to include short, human readable descriptions for 1987nodes in the sysctl tree. 1988The descriptions can be retrieved programmatically (see 1989.Xr sysctl 3 ) , 1990or by the sysctl binary itself (see 1991.Xr sysctl 8 ) . 1992The descriptions are meant to give an indication of the purpose and/or 1993effects of a given node's value, not replace the documentation for the 1994given subsystem as a whole. 1995.El 1996.Ss System V IPC Options 1997.Bl -ohang 1998.It Cd options SYSVMSG 1999Includes support for 2000.At V 2001style message queues. 2002See 2003.Xr msgctl 2 , 2004.Xr msgget 2 , 2005.Xr msgrcv 2 , 2006.Xr msgsnd 2 . 2007.It Cd options SYSVSEM 2008Includes support for 2009.At V 2010style semaphores. 2011See 2012.Xr semctl 2 , 2013.Xr semget 2 , 2014.Xr semop 2 . 2015.It Cd options SEMMNI=value 2016Sets the number of 2017.At V 2018style semaphore identifiers. 2019The GENERIC config file for your port will have the default. 2020.It Cd options SEMMNS=value 2021Sets the number of 2022.At V 2023style semaphores in the system. 2024The GENERIC config file for your port will have the default. 2025.It Cd options SEMUME=value 2026Sets the maximum number of undo entries per process for 2027.At V 2028style semaphores. 2029The GENERIC config file for your port will have the default. 2030.It Cd options SEMMNU=value 2031Sets the number of undo structures in the system for 2032.At V 2033style semaphores. 2034The GENERIC config file for your port will have the default. 2035.It Cd options SYSVSHM 2036Includes support for 2037.At V 2038style shared memory. 2039See 2040.Xr shmat 2 , 2041.Xr shmctl 2 , 2042.Xr shmdt 2 , 2043.Xr shmget 2 . 2044.It Cd options SHMMAXPGS=value 2045Sets the maximum number of 2046.At V 2047style shared memory pages that are available through the 2048.Xr shmget 2 2049system call. 2050Default value is 1024 on most ports. 2051See 2052.Pa /usr/include/machine/vmparam.h 2053for the default. 2054.El 2055.Ss VM Related Options 2056.Bl -ohang 2057.It Cd options NMBCLUSTERS=value 2058The number of mbuf clusters the kernel supports. 2059Mbuf clusters are MCLBYTES in size (usually 2k). 2060This is used to compute the size of the kernel VM map 2061.Em mb_map , 2062which maps mbuf clusters. 2063Default on most ports is 1024 (2048 with 2064.Dq options GATEWAY 2065). 2066See 2067.Pa /usr/include/machine/param.h 2068for exact default information. 2069Increase this value if you get 2070.Dq mclpool limit reached 2071messages. 2072.It Cd options NKMEMPAGES=value 2073.It Cd options NKMEMPAGES_MIN=value 2074.It Cd options NKMEMPAGES_MAX=value 2075Size of kernel VM map 2076.Em kmem_map , 2077in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2078from the 2079.Xr sysctl 8 2080variable 2081.Em hw.pagesize 2082). 2083This VM map is used to map the kernel malloc arena. 2084The kernel attempts to auto-size this map based on the amount of 2085physical memory in the system. 2086Platform-specific code may place bounds on this computed size, 2087which may be viewed with the 2088.Xr sysctl 8 2089variable 2090.Em vm.nkmempages . 2091See 2092.Pa /usr/include/machine/param.h 2093for the default upper and lower bounds. 2094The related options 2095.Sq NKMEMPAGES_MIN 2096and 2097.Sq NKMEMPAGES_MAX 2098allow the bounds to be overridden in the kernel configuration file. 2099These options are provided in the event the computed value is 2100insufficient resulting in an 2101.Dq out of space in kmem_map 2102panic. 2103.It Cd options SB_MAX=value 2104Sets the max size in bytes that a socket buffer is allowed to occupy. 2105The default is 256k, but sometimes it needs to be increased, for example 2106when using large TCP windows. 2107This option can be changed via 2108.Xr sysctl 8 2109as well. 2110.It Cd options SOMAXKVA=value 2111Sets the maximum size of kernel virtual memory that the socket buffers 2112are allowed to use. 2113The default is 16MB, but in situations where for example large TCP 2114windows are used this value must also be increased. 2115This option can be changed via 2116.Xr sysctl 8 2117as well. 2118.It Cd options BUFCACHE=value 2119Size of the buffer cache as a percentage of total available 2120.Tn RAM . 2121Ignored if BUFPAGES is also specified. 2122.It Cd options NBUF=value 2123Sets the number of buffer headers available, i.e., the number of 2124open files that may have a buffer cache entry. 2125Each buffer header 2126requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2127The default value is machine dependent, but is usually equal to the 2128value of BUFPAGES. 2129If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2130then NBUF may be reduced at run time so that the storage allocated 2131for buffer headers doesn't exceed that limit. 2132.It Cd options BUFPAGES=value 2133These options set the number of pages available for the buffer cache. 2134Their default value is a machine dependent value, often calculated as 2135between 5% and 10% of total available 2136.Tn RAM . 2137.It Cd options MAXTSIZ=bytes 2138Sets the maximum size limit of a process' text segment. 2139See 2140.Pa /usr/include/machine/vmparam.h 2141for the port-specific default. 2142.It Cd options DFLDSIZ=bytes 2143Sets the default size limit of a process' data segment, the value that 2144will be returned as the soft limit for 2145.Dv RLIMIT_DATA 2146(as returned by 2147.Xr getrlimit 2 ) . 2148See 2149.Pa /usr/include/machine/vmparam.h 2150for the port-specific default. 2151.It Cd options MAXDSIZ=bytes 2152Sets the maximum size limit of a process' data segment, the value that 2153will be returned as the hard limit for 2154.Dv RLIMIT_DATA 2155(as returned by 2156.Xr getrlimit 2 ) . 2157See 2158.Pa /usr/include/machine/vmparam.h 2159for the port-specific default. 2160.It Cd options DFLSSIZ=bytes 2161Sets the default size limit of a process' stack segment, the value that 2162will be returned as the soft limit for 2163.Dv RLIMIT_STACK 2164(as returned by 2165.Xr getrlimit 2 ) . 2166See 2167.Pa /usr/include/machine/vmparam.h 2168for the port-specific default. 2169.It Cd options MAXSSIZ=bytes 2170Sets the maximum size limit of a process' stack segment, the value that 2171will be returned as the hard limit for 2172.Dv RLIMIT_STACK 2173(as returned by 2174.Xr getrlimit 2 ) . 2175See 2176.Pa /usr/include/machine/vmparam.h 2177for the port-specific default. 2178.It Cd options DUMP_ON_PANIC=integer 2179Defaults to one. 2180If set to zero, the kernel will not dump to the dump device when 2181it panics, though dumps can still be forced via 2182.Xr ddb 4 2183with the 2184.Dq sync 2185command. 2186Note that this sets the value of the 2187.Em kern.dump_on_panic 2188.Xr sysctl 3 2189variable which may be changed at run time -- see 2190.Xr sysctl 8 2191for details. 2192.It Cd options USE_TOPDOWN_VM 2193User space memory allocations (as made by 2194.Xr mmap 2 ) 2195will be arranged in a 2196.Dq top down 2197fashion instead of the traditional 2198.Dq upwards from MAXDSIZ \&+ vm_daddr 2199method. 2200This includes the placement of 2201.Xr ld.so 1 . 2202Arranging memory in this manner allows either (or both of) the heap or 2203.Xr mmap 2 2204allocated space to grow larger than traditionally possible. 2205This option is not available on all ports, but is instead expected to be 2206offered on a port-by-port basis, after which some ports will commit to 2207using it by default. 2208See the files 2209.Pa /usr/include/uvm/uvm_param.h 2210for some implementation details, and 2211.Pa /usr/include/machine/vmparam.h 2212for port specific details including availability. 2213.It Cd options VMSWAP 2214Enable paging device/file support. 2215This option is on by default. 2216.It Cd options PDPOLICY_CLOCKPRO 2217Use CLOCK-Pro, an alternative page replace policy. 2218.El 2219.Ss Security Options 2220.Bl -ohang 2221.It Cd options INSECURE 2222Hardwires the kernel security level at \-1. 2223This means that the system 2224always runs in secure level \-1 mode, even when running multiuser. 2225See the manual page for 2226.Xr init 8 2227for details on the implications of this. 2228The kernel secure level may manipulated by the superuser by altering the 2229.Em kern.securelevel 2230.Xr sysctl 3 2231variable (the secure level may only be lowered by a call from process ID 1, 2232i.e., 2233.Xr init 8 ) . 2234See also 2235.Xr secmodel_securelevel 9 , 2236.Xr sysctl 8 2237and 2238.Xr sysctl 3 . 2239.It Cd options VERIFIED_EXEC_FP_MD5 2240Enables support for MD5 hashes in Veriexec. 2241.It Cd options VERIFIED_EXEC_FP_SHA1 2242Enables support for SHA1 hashes in Veriexec. 2243.It Cd options VERIFIED_EXEC_FP_RMD160 2244Enables support for RMD160 hashes in Veriexec. 2245.It Cd options VERIFIED_EXEC_FP_SHA256 2246Enables support for SHA256 hashes in Veriexec. 2247.It Cd options VERIFIED_EXEC_FP_SHA384 2248Enables support for SHA384 hashes in Veriexec. 2249.It Cd options VERIFIED_EXEC_FP_SHA512 2250Enables support for SHA512 hashes in Veriexec. 2251.It Cd options PAX_MPROTECT=value 2252Enables PaX MPROTECT, 2253.Xr mprotect 2 2254restrictions from the PaX project. 2255.Pp 2256The 2257.Ar value 2258is the default value for the 2259.Em global 2260knob, see 2261.Xr sysctl 3 . 2262If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2263using 2264.Xr paxctl 8 . 2265If 1, PaX MPROTECT will be enabled for all programs. 2266Programs can be exempted using 2267.Xr paxctl 8 . 2268.Pp 2269See 2270.Xr security 8 2271for more details. 2272.It Cd options PAX_SEGVGUARD=value 2273Enables PaX Segvguard. 2274.Pp 2275The 2276.Ar value 2277is the default value for the 2278.Em global 2279knob, see 2280.Xr sysctl 3 . 2281If 0, PaX Segvguard will be enabled only if explicitly set on programs 2282using 2283.Xr paxctl 8 . 2284If 1, PaX Segvguard will be enabled to all programs, and exemption can 2285be done using 2286.Xr paxctl 8 . 2287.Pp 2288See 2289.Xr security 8 2290for more details. 2291.It Cd options PAX_ASLR=value 2292Enables PaX ASLR. 2293.Pp 2294The 2295.Ar value 2296is the default value for the 2297.Em global 2298knob, see 2299.Xr sysctl 3 . 2300If 0, PaX ASLR will be enabled only if explicitly set on programs 2301using 2302.Xr paxctl 8 . 2303If 1, PaX ASLR will be enabled to all programs, and exemption can 2304be done using 2305.Xr paxctl 8 . 2306.Pp 2307See 2308.Xr security 8 2309for more details. 2310.It Cd options USER_VA0_DISABLE_DEFAULT=value 2311Sets the initial value of the flag which controls whether user programs 2312can map virtual address 0. 2313The flag can be changed at runtime by 2314.Xr sysctl 3 . 2315.El 2316.Ss amiga-specific Options 2317.Bl -ohang 2318.It Cd options BB060STUPIDROM 2319When the bootloader (which passes 2320.Tn AmigaOS 2321.Tn ROM 2322information) claims we have a 68060 2323.Tn CPU 2324without 2325.Tn FPU , 2326go look into the Processor Configuration Register (PCR) to find out. 2327You need this with 2328.Tn Amiga 2329.Tn ROM Ns s 2330up to (at least) V40.xxx (OS3.1), 2331when you boot via the bootblocks and don't have a DraCo. 2332.It Cd options IOBZCLOCK=frequency 2333The IOBlix boards come with two different serial master clocks: older ones 2334use 24 MHz, newer ones use 22.1184 MHz. 2335The driver normally assumes the latter. 2336If your board uses 24 MHz, you can recompile your kernel with 2337options IOBZCLOCK=24000000 2338or patch the kernel variable 2339.Tn iobzclock 2340to the same value. 2341.It Cd options LIMITMEM=value 2342If there, limit the part of the first memory bank used by 2343.Nx 2344to value megabytes. 2345Default is unlimited. 2346.It Cd options NKPTADD=addvalue 2347.It Cd options NKPTADDSHIFT=shiftvalue 2348The 2349.Tn CPU 2350specific 2351.Tn MMU 2352table for the kernel is pre-allocated at kernel startup time. 2353Part of it is scaled with 2354.Va maxproc , 2355to have enough room to hold the user program 2356.Tn MMU 2357tables; the second part is a fixed amount for the kernel itself. 2358.Pp 2359The third part accounts for the size of the file buffer cache. 2360Its size is either 2361.Dv NKPTADD 2362pages (if defined) or memory size in bytes divided by two to 2363the power of 2364.Dv NKPTADDSHIFT . 2365The default is undefined 2366.Dv NKPTADD 2367and 2368.Dv NKPTADDSHIFT=24 , 2369allowing for 16 buffers per megabyte of main memory (while 2370a GENERIC kernel allocates about half of that). 2371When you get "can't get KPT page" panics, you should increase 2372.Dv NKPTADD 2373(if defined), or decrease 2374.Dv NKPTADDSHIFT 2375by one. 2376.It Cd options P5PPC68KBOARD 2377Add special support for Phase5 mixed 68k+PPC boards. 2378Currently, this only affects rebooting from 2379.Nx 2380and is only needed on 68040+PPC, not on 238168060+PPC; without this, affected machines will hang after 2382.Nx 2383has shut 2384down and will only restart after a keyboard reset or a power cycle. 2385.El 2386.Ss arm32-specific Options 2387.Bl -ohang 2388.It Cd options FRENCH_KBD 2389Include translation for French keyboards when using 2390.Em pccons 2391on a Shark. 2392.It Cd options FINNISH_KBD 2393Include translation for Finnish keyboards when using 2394.Em pccons 2395on a Shark. 2396.It Cd options GERMAN_KBD 2397Include translation for German keyboards when using 2398.Em pccons 2399on a Shark. 2400.It Cd options NORWEGIAN_KBD 2401Include translation for French keyboards when using 2402.Em pccons 2403on a Shark. 2404.El 2405.Ss amd64-specific Options 2406.Bl -ohang 2407.It Cd options ENHANCED_SPEEDSTEP 2408Include support for the 2409.Tn Enhanced SpeedStep Technology 2410present in newer 2411.Tn CPU Ns s . 2412.It Cd options EST_FREQ_USERWRITE 2413Allow any user to change the frequency of an 2414.Tn Enhanced SpeedStep Technology 2415capable 2416.Tn CPU . 2417.It Cd options INTEL_ONDEMAND_CLOCKMOD 2418This enables the On Demand Clock Modulation by software 2419on Intel 2420.Tn CPUs 2421supporting the Thermal Monitor feature (TM). 2422You can select the duty cycle with 2423.Xr sysctl 8 2424in the node 2425.Em machdep.clockmod 2426if supported. 2427.It Cd options POWERNOW_K8 2428Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2429Technology, used to change the CPU voltage and frequency 2430on the fly. 2431.El 2432.Ss atari-specific Options 2433.Bl -ohang 2434.It Cd options DISKLABEL_AHDI 2435Include support for AHDI (native Atari) disklabels. 2436.It Cd options DISKLABEL_NBDA 2437Include support for 2438.Nx Ns Tn /atari 2439labels. 2440If you don't set this option, it will be set automatically. 2441.Nx Ns Tn /atari 2442will not work without it. 2443.It Cd options FALCON_SCSI 2444Include support for the 5380-SCSI configuration as found on the Falcon. 2445.It Cd options RELOC_KERNEL 2446If set, the kernel will relocate itself to TT-RAM, if possible. 2447This will give you a slightly faster system. 2448.Em Beware 2449that on some TT030 systems, 2450the system will frequently dump with MMU-faults with this option enabled. 2451.It Cd options SERCONSOLE 2452Allow the modem1-port to act as the system-console. 2453A carrier should be active on modem1 during system boot to active 2454the console functionality. 2455.It Cd options TT_SCSI 2456Include support for the 5380-SCSI configuration as found on the TT030 2457and Hades. 2458.El 2459.Ss i386-specific Options 2460.Bl -ohang 2461.It Cd options ENHANCED_SPEEDSTEP 2462Include support for the 2463.Tn Enhanced SpeedStep Technology 2464present in newer 2465.Tn CPU Ns s . 2466.It Cd options EST_FREQ_USERWRITE 2467Allow any user to change the frequency of an 2468.Tn Enhanced SpeedStep Technology 2469capable 2470.Tn CPU . 2471.It Cd options INTEL_ONDEMAND_CLOCKMOD 2472This enables the On Demand Clock Modulation by software 2473on Intel 2474.Tn CPUs 2475supporting the Thermal Monitor feature (TM). 2476You can select the duty cycle with 2477.Xr sysctl 8 2478in the node 2479.Em machdep.clockmod 2480if supported. 2481.It Cd options POWERNOW_K7 2482Include support for the AMD 2483.Tn PowerNow! Technology 2484present in AMD Athlon Mobile processors. 2485.It Cd options VIA_PADLOCK 2486Include support for the 2487.Tn AES 2488encryption instructions of the 2489.Tn VIA PadLock Security engine , 2490which is attached as a provider to the opencrypto framework. 2491.It Cd options CPURESET_DELAY=value 2492Specifies the time (in millisecond) to wait before doing a hardware reset 2493in the last phase of a reboot. 2494This gives the user a chance to see error messages from the shutdown 2495operations (like NFS unmounts, buffer cache flush, etc ...). 2496Setting this to 0 will disable the delay. 2497Default is 2 seconds. 2498.It Cd options VM86 2499Include support for virtual 8086 mode, used by 2500.Tn DOS 2501emulators and X servers to run BIOS code, e.g., for some VESA routines. 2502.It Cd options USER_LDT 2503Include i386-specific system calls for modifying the local descriptor table, 2504used by Windows emulators. 2505.It Cd options REALBASEMEM=integer 2506Overrides the base memory size passed in from the boot block. 2507(Value given in kilobytes.) 2508Use this option only if the boot block reports the size incorrectly. 2509(Note that some 2510.Tn BIOS Ns es 2511put the extended 2512.Tn BIOS 2513data area at the top of base memory, and therefore report a smaller 2514base memory size to prevent programs overwriting it. 2515This is correct behavior, and you should not use the 2516.Em REALBASEMEM 2517option to access this memory). 2518.It Cd options REALEXTMEM=integer 2519Overrides the extended memory size passed in from the boot block. 2520(Value given in kilobytes. 2521Extended memory does not include the first megabyte.) 2522Use this option only if the boot block reports the size incorrectly. 2523.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2524Select a non-US keyboard layout for the 2525.Em pccons 2526console driver. 2527.It Cd options CYRIX_CACHE_WORKS 2528Relevant only to the Cyrix 486DLC CPU. 2529This option is used to turn on the cache in hold-flush mode. 2530It is not turned on by default because it is known to have problems in 2531certain motherboard implementations. 2532.It Cd options CYRIX_CACHE_REALLY_WORKS 2533Relevant only to the Cyrix 486DLC CPU. 2534This option is used to turn on the cache in write-back mode. 2535It is not turned on by default because it is known to have problems in 2536certain motherboard implementations. 2537In order for this option to take effect, option 2538.Em CYRIX_CACHE_WORKS 2539must also be specified. 2540.It Cd options PCIBIOS 2541Enable support for initializing the 2542.Tn PCI 2543bus using information from the 2544.Tn BIOS . 2545See 2546.Xr pcibios 4 2547for details. 2548.It Cd options KSTACK_CHECK_DR0 2549Detect kernel stack overflow using DR0 register. 2550This option uses DR0 register exclusively so you can't use DR0 register for 2551other purpose (e.g., hardware breakpoint) if you turn this on. 2552.It Cd options MTRR 2553Include support for accessing MTRR registers from user-space. 2554See 2555.Xr i386_get_mtrr 2 . 2556.It Cd options BEEP_ONHALT 2557Make the system speaker emit several beeps when it is completely safe to 2558power down the computer after a 2559.Xr halt 8 2560command. 2561Requires 2562.Xr sysbeep 4 2563support. 2564.It Cd options BEEP_ONHALT_COUNT=times 2565Number of times to beep the speaker when 2566.Cd options BEEP_ONHALT 2567is enabled. 2568Defaults to 3. 2569.It Cd options BEEP_ONHALT_PITCH=hz 2570The tone frequency used when 2571.Cd options BEEP_ONHALT 2572option, in hertz. 2573Defaults to 1500. 2574.It Cd options BEEP_ONHALT_PERIOD=msecs 2575The duration of each beep when 2576.Cd options BEEP_ONHALT 2577is enabled, in milliseconds. 2578Defaults to 250. 2579.It Cd options MULTIBOOT 2580Makes the kernel Multiboot-compliant, allowing it to be booted through 2581a Multiboot-compliant boot manager such as GRUB. 2582See 2583.Xr multiboot 8 2584for more information. 2585.It Cd options SPLASHSCREEN 2586Display a splash screen during boot. 2587.It Cd options SPLASHSCREEN_PROGRESS 2588Display a progress bar at the splash screen during boot. 2589This option requires 2590.Em SPLASHSCREEN . 2591.El 2592.Ss isa-specific Options 2593Options specific to 2594.Xr isa 4 2595busses. 2596.Bl -ohang 2597.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2598Control the section of IO bus space used for PCMCIA bus space mapping. 2599Ideally the probed defaults are satisfactory, however in practice 2600that is not always the case. 2601See 2602.Xr pcmcia 4 2603for details. 2604.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2605Controls the allowable interrupts that may be used for 2606.Tn PCMCIA 2607devices. 2608This mask is a logical-or of power-of-2s of allowable interrupts: 2609.Bd -literal -offset 04n 2610.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2611 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2612 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2613 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2614 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2615.Ed 2616.It Cd options PCKBC_CNATTACH_SELFTEST 2617Perform a self test of the keyboard controller before attaching it as a 2618console. 2619This might be necessary on machines where we boot on cold iron, and 2620pckbc refuses to talk until we request a self test. 2621Currently only the netwinder port uses it. 2622.It Cd options PCKBD_CNATTACH_MAY_FAIL 2623If this option is set the PS/2 keyboard will not be used as the console 2624if it cannot be found during boot. 2625This allows other keyboards, like USB, to be the console keyboard. 2626.It Cd options PCKBD_LAYOUT=layout 2627Sets the default keyboard layout, see 2628.Xr pckbd 4 . 2629.El 2630.Ss m68k-specific Options 2631.Bl -ohang 2632.It Cd options FPU_EMULATE 2633Include support for MC68881/MC68882 emulator. 2634.It Cd options FPSP 2635Include support for 68040 floating point. 2636.It Cd options M68020,M68030,M68040,M68060 2637Include support for a specific 2638.Tn CPU , 2639at least one (the one you are using) should be specified. 2640.It Cd options M060SP 2641Include software support for 68060. 2642This provides emulation of unimplemented 2643integer instructions as well as emulation of unimplemented floating point 2644instructions and data types and software support for floating point traps. 2645.El 2646.Ss powerpc-specific Options (OEA Only) 2647.Bl -ohang 2648.It Cd options PMAP_MEMLIMIT=value 2649Limit the amount of memory seen by the kernel to 2650.Ar value 2651bytes. 2652.It Cd options PTEGCOUNT=value 2653Specify the size of the page table as 2654.Ar value 2655PTE groups. 2656Normally, one PTEG is allocated per physical page frame. 2657.El 2658.Ss sparc-specific Options 2659.Bl -ohang 2660.It Cd options AUDIO_DEBUG 2661Enable simple event debugging of the logging of the 2662.Xr audio 4 2663device. 2664.It Cd options BLINK 2665Enable blinking of LED. 2666Blink rate is full cycle every N seconds for 2667N \*[Lt] then current load average. 2668See 2669.Xr getloadavg 3 . 2670.\" .It Cd options COLORFONT_CACHE 2671.\" What does this do? 2672.It Cd options COUNT_SW_LEFTOVERS 2673Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2674sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2675variables accessible from 2676.Xr ddb 4 . 2677See 2678.Xr sw 4 . 2679.It Cd options DEBUG_ALIGN 2680Adds debugging messages calls when user-requested alignment fault 2681handling happens. 2682.It Cd options DEBUG_EMUL 2683Adds debugging messages calls for emulated floating point and 2684alignment fixing operations. 2685.It Cd options DEBUG_SVR4 2686Prints registers messages calls for emulated SVR4 getcontext and 2687setcontext operations. 2688See 2689.Em options COMPAT_SVR4 . 2690.It Cd options EXTREME_DEBUG 2691Adds debugging functions callable from 2692.Xr ddb 4 . 2693The debug_pagetables, test_region and print_fe_map 2694functions print information about page tables for the SUN4M 2695platforms only. 2696.It Cd options EXTREME_EXTREME_DEBUG 2697Adds extra info to 2698.Em options EXTREME_DEBUG . 2699.It Cd options FPU_CONTEXT 2700Make 2701.Em options COMPAT_SVR4 2702getcontext and setcontext include floating point registers. 2703.It Cd options MAGMA_DEBUG 2704Adds debugging messages to the 2705.Xr magma 4 2706device. 2707.It Cd options RASTERCONS_FULLSCREEN 2708Use the entire screen for the console. 2709.It Cd options RASTERCONS_SMALLFONT 2710Use the Fixed font on the console, instead of the normal font. 2711.It Cd options SUN4 2712Support sun4 class machines. 2713.It Cd options SUN4C 2714Support sun4c class machines. 2715.It Cd options SUN4M 2716Support sun4m class machines. 2717.It Cd options SUN4_MMU3L 2718.\" XXX ??? 2719Enable support for sun4 3-level MMU machines. 2720.It Cd options V9 2721Enable SPARC V9 assembler in 2722.Xr ddb 4 . 2723.El 2724.Ss sparc64-specific Options 2725.Bl -ohang 2726.It Cd options AUDIO_DEBUG 2727Enable simple event debugging of the logging of the 2728.Xr audio 4 2729device. 2730.It Cd options BLINK 2731Enable blinking of LED. 2732Blink rate is full cycle every N seconds for 2733N \*[Lt] then current load average. 2734See 2735.Xr getloadavg 3 . 2736.El 2737.Ss x68k-specific Options 2738.Bl -ohang 2739.It Cd options EXTENDED_MEMORY 2740Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2741.It Cd options JUPITER 2742Include support for Jupiter-X MPU accelerator 2743.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2744Use the built-in serial port as the system-console. 2745Speed is specified in bps, defaults to 9600. 2746.It Cd options ITE_KERNEL_ATTR=value 2747Set the kernel message attribute for ITE. 2748Value, an integer, is a logical or of the following values: 2749.Bl -tag -width 4n -compact -offset indent 2750.It 1 2751color inversed 2752.It 2 2753underlined 2754.It 4 2755bolded 2756.El 2757.El 2758.\" The following requests should be uncommented and used where appropriate. 2759.\" .Sh FILES 2760.\" .Sh EXAMPLES 2761.Sh SEE ALSO 2762.Xr config 1 , 2763.Xr gdb 1 , 2764.Xr ktrace 1 , 2765.Xr pmc 1 , 2766.Xr quota 1 , 2767.Xr vndcompress 1 , 2768.Xr gettimeofday 2 , 2769.Xr i386_get_mtrr 2 , 2770.Xr i386_iopl 2 , 2771.Xr msgctl 2 , 2772.Xr msgget 2 , 2773.Xr msgrcv 2 , 2774.Xr msgsnd 2 , 2775.Xr ntp_adjtime 2 , 2776.Xr ntp_gettime 2 , 2777.Xr reboot 2 , 2778.Xr semctl 2 , 2779.Xr semget 2 , 2780.Xr semop 2 , 2781.Xr shmat 2 , 2782.Xr shmctl 2 , 2783.Xr shmdt 2 , 2784.Xr shmget 2 , 2785.Xr sysctl 3 , 2786.Xr apm 4 , 2787.Xr ddb 4 , 2788.Xr inet 4 , 2789.Xr iso 4 , 2790.Xr md 4 , 2791.Xr ns 4 , 2792.Xr pcibios 4 , 2793.Xr pcmcia 4 , 2794.Xr ppp 4 , 2795.Xr userconf 4 , 2796.Xr vnd 4 , 2797.Xr wscons 4 , 2798.Xr config 5 , 2799.Xr edquota 8 , 2800.Xr init 8 , 2801.Xr mdsetimage 8 , 2802.Xr mount_cd9660 8 , 2803.Xr mount_fdesc 8 , 2804.Xr mount_kernfs 8 , 2805.Xr mount_lfs 8 , 2806.Xr mount_mfs 8 , 2807.Xr mount_msdos 8 , 2808.Xr mount_nfs 8 , 2809.Xr mount_ntfs 8 , 2810.Xr mount_null 8 , 2811.Xr mount_portal 8 , 2812.Xr mount_procfs 8 , 2813.Xr mount_udf 8 , 2814.Xr mount_umap 8 , 2815.Xr mount_union 8 , 2816.Xr mrouted 8 , 2817.Xr newfs_lfs 8 , 2818.Xr ntpd 8 , 2819.Xr quotaon 8 , 2820.Xr rpc.rquotad 8 , 2821.Xr sysctl 8 , 2822.Xr in_getifa 9 2823.Sh HISTORY 2824The 2825.Nm 2826man page first appeared in 2827.Nx 1.3 . 2828.Sh BUGS 2829The 2830.Em EON 2831option should be a pseudo-device, and is also very fragile. 2832