1.\" $NetBSD: options.4,v 1.437 2014/03/23 00:50:20 dholland 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 March 22, 2014 34.Dt OPTIONS 4 35.Os 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Qq Ar filename 66Conditionally includes another kernel configuration file whose name is 67.Ar filename , 68which may be double-quoted and may be an explicit path or relative to 69the kernel source directory. 70Failure to open the named file is ignored. 71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ 72Oo dumps on Ar dumpdev Oc 73Defines a configuration whose kernel executable is named 74.Ar exec_name , 75normally 76.Dq netbsd , 77with its root file system of type 78.Ar fstype 79on the device 80.Ar rootdev , 81and optionally specifying the location of kernel core dumps on the device 82.Ar dumpdev . 83.Ar dev 84or 85.Ar dumpdev 86and 87.Ar fstype 88may be specified as 89.Dq \&? , 90which is a wild card. 91The root 92.Ar fstype 93and 94.Ar dumpdev 95are optional and assumed to be wild carded if they are not specified. 96.It Ar device_instance No at Ar attachment \ 97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc 98Define an instance of the device driver 99.Ar device_instance 100that attaches to the bus or device named 101.Ar attachment . 102An 103.Ar attachment 104may require additional information on where the device can be found, such 105as an address, channel, function, offset, and/or slot, referred to as 106.Ar locators , 107whose 108.Ar value 109often may be a wild card, 110.Dq \&? . 111Some device drivers have one or more 112.Ar flags 113that can be adjusted to affect the way they operate. 114.It Sy file-system Ar fs_name Op , Ar fs_name Op ... 115Include support for the file-system 116.Ar fs_name . 117.It Sy ident Qq Ar string 118Sets the kernel identification string to 119.Ar string . 120.It Sy include Qq Ar filename 121Functions the same as 122.Ar cinclude , 123except failure to open 124.Ar filename 125produces a fatal error. 126.It Sy options Ar option_name Op , Ar option_name=value Op ... 127Specifies (or sets) the option, or comma-separated list of options, 128.Ar option_name . 129Some options expect to be assigned a value, which may be an integer, 130a double-quoted word, a bare word, or an empty string 131.Pq Qq . 132Note that those are eventually handled by the C compiler, so the rules 133of that language apply. 134.Pp 135.Em Note : 136Options that are not defined by device definition files are passed to 137the compile process as 138.Fl D 139flags to the C compiler. 140.It Sy makeoptions Ar name=value 141Defines a 142.Xr make 1 143macro 144.Ar name 145with the value 146.Ar value 147in the kernel Makefile. 148.It Sy maxusers Ar integer 149Set the maxusers variable in the kernel. 150.It Sy no Ar keyword Ar name Op Ar arguments Op ... 151For the 152.Xr config 1 153.Ar keywords 154file-system, makeoptions, options, and pseudo-device, 155.Ar no 156removes the file-system, makeoption, options, or pseudo-device, 157.Ar name . 158This is useful when a kernel configuration file includes another which 159has undesired options. 160.Pp 161For example, a local configuration file that wanted the kitchen sink, but 162not COMPAT_09 or bridging, might be: 163.Bd -literal -offset indent 164include "arch/i386/conf/GENERIC" 165no options COMPAT_09 166no pseudo-device bridge 167.Ed 168.It Sy pseudo-device Ar name Op Ar N 169Includes support for the pseudo-device 170.Ar name . 171Some pseudo-devices can have multiple or 172.Ar N 173instances. 174.El 175.Ss Compatibility Options 176.Bl -ohang 177.It Cd options COMPAT_09 178Enable binary compatibility with 179.Nx 0.9 . 180This enables support for 18116-bit user, group, and process IDs (following revisions support 18232-bit identifiers). 183It also allows the use of the deprecated 184.Xr getdomainname 3 , 185.Xr setdomainname 3 , 186and 187.Xr uname 3 188syscalls. 189This option also allows using numeric file system identifiers rather 190than strings. 191Post 192.Nx 0.9 193versions use string identifiers. 194.It Cd options COMPAT_10 195Enable binary compatibility with 196.Nx 1.0 . 197This option allows the use of the file system name of 198.Dq ufs 199as an alias for 200.Dq ffs . 201The name 202.Dq ffs 203should be used post 1.0 in 204.Pa /etc/fstab 205and other files. 206It also adds old syscalls for the 207.At V 208shared memory interface. 209This was changed post 1.0 to work on 64-bit architectures. 210This option also enables 211.Dq sgtty 212compatibility, without which programs using the old interface produce 213an 214.Dq inappropriate ioctl 215error, and 216.Pa /dev/io 217only works when this option is set in the kernel, 218see 219.Xr io 4 220on ports that support it. 221.It Cd options COMPAT_11 222Enable binary compatibility with 223.Nx 1.1 . 224This allows binaries running on the i386 port to gain direct access to 225the io ports by opening 226.Pa /dev/io 227read/write. 228This functionality was replaced by 229.Xr i386_iopl 2 230post 1.1. 231On the 232.Tn Atari 233port, the location of the disk label was moved after 1.1. 234When the 235.Em COMPAT_11 236option is set, the kernel will read (pre) 1.1 style disk labels as a 237last resort. 238When a disk label is re-written, the old style label will be replaced 239with a post 1.1 style label. 240This also enables the 241.Em EXEC_ELF_NOTELESS 242option. 243.It Cd options COMPAT_12 244Enable binary compatibility with 245.Nx 1.2 . 246This allows the use of old syscalls for 247.Fn reboot 248and 249.Fn swapon . 250The syscall numbers were changed post 1.2 to add functionality to the 251.Xr reboot 2 252syscall, and the new 253.Xr swapctl 2 254interface was introduced. 255This also enables the 256.Em EXEC_ELF_NOTELESS 257option. 258.It Cd options COMPAT_13 259Enable binary compatibility with 260.Nx 1.3 . 261This allows the use of old syscalls for 262.Fn sigaltstack , 263and also enables the old 264.Xr swapctl 2 265command 266.Dv SWAP_STATS 267(now called 268.Dv SWAP_OSTATS ) , 269which does not include the 270.Fa se_path 271member of 272.Va struct swapent . 273.It Cd options COMPAT_14 274Enable binary compatibility with 275.Nx 1.4 . 276This allows some old 277.Xr ioctl 2 278on 279.Xr wscons 4 280to be performed, and allows the 281.Dv NFSSVC_BIOD 282mode of the 283.Xr nfssvc 2 284system call to be used for compatibility with the deprecated nfsiod program. 285.It Cd options COMPAT_15 286Enable binary compatibility with 287.Nx 1.5 . 288Since there were no API changes from 289.Nx 1.5 290and 291.Nx 1.6 , 292this option does nothing. 293.It Cd options COMPAT_16 294Enable binary compatibility with 295.Nx 1.6 . 296This allows the use of old signal trampoline code which has been deprecated 297with the addition of 298.Xr siginfo 2 . 299.It Cd options COMPAT_20 300Enable binary compatibility with 301.Nx 2.0 . 302This allows the use of old syscalls for 303.Fn statfs , 304.Fn fstatfs , 305.Fn getfsstat 306and 307.Fn fhstatfs , 308which have been deprecated with the addition of the 309.Xr statvfs 2 , 310.Xr fstatvfs 2 , 311.Xr getvfsstat 2 312and 313.Xr fhstatvfs 2 314system calls. 315.It Cd options COMPAT_30 316Enable binary compatibility with 317.Nx 3.0 . 318See 319.Xr compat_30 8 320for details about the changes made after the 321.Nx 3.0 322release. 323.It Cd options COMPAT_43 324Enables compatibility with 325.Bx 4.3 . 326This adds an old syscall for 327.Xr lseek 2 . 328It also adds the ioctls for 329.Dv TIOCGETP 330and 331.Dv TIOCSETP . 332The return values for 333.Xr getpid 2 , 334.Xr getgid 2 , 335and 336.Xr getuid 2 337syscalls are modified as well, to return the parent's PID and 338UID as well as the current process's. 339It also enables the deprecated 340.Dv NTTYDISC 341terminal line discipline. 342It also provides backwards compatibility with 343.Dq old 344SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 345binary compatibility with code written before the introduction of the 346sa_len field in sockaddrs. 347It also enables 348support for some older pre 349.Bx 4.4 350socket calls. 351.It Cd options COMPAT_BSDPTY 352This option is currently on by default and enables the pty multiplexer 353.Xr ptm 4 354and 355.Xr ptmx 4 356to find and use ptys named 357.Pa /dev/ptyXX 358(master) and 359.Pa /dev/ttyXX 360(slave). 361Eventually this option will become optional as ptyfs based pseudo-ttys become 362the default, see 363.Xr mount_ptyfs 8 . 364.It Cd options COMPAT_SVR4 365On those architectures that support it, this enables binary 366compatibility with 367.At V.4 368applications built for the same architecture. 369This currently includes the i386, m68k, and sparc ports. 370.It Cd options COMPAT_LINUX 371On those architectures that support it, this enables binary 372compatibility with Linux ELF and 373.Xr a.out 5 374applications built for the same architecture. 375This currently includes the alpha, arm, i386, m68k, mips, powerpc and 376x86_64 ports. 377.It Cd options COMPAT_LINUX32 378On those 64 bit architectures that support it, this enables binary 379compatibility with 32 bit Linux binaries. 380For now this is limited to running i386 ELF Linux binaries on amd64. 381.It Cd options COMPAT_SUNOS 382On those architectures that support it, this enables binary 383compatibility with 384.Tn SunOS 4.1 385applications built for the same architecture. 386This currently includes the sparc, sparc64 and most or all m68k ports. 387Note that the sparc64 requires the 388.Em COMPAT_NETBSD32 389option for 64-bit kernels, in addition to this option. 390.It Cd options COMPAT_ULTRIX 391On those architectures that support it, this enables binary 392compatibility with 393.Tn ULTRIX 394applications built for the same architecture. 395This currently is limited to the pmax. 396The functionality of this option is unknown. 397.It Cd options COMPAT_FREEBSD 398On those architectures that support it, this enables binary 399compatibility with 400.Fx 401applications built for the same architecture. 402At the moment this is limited to the i386 port. 403.It Cd options COMPAT_IBCS2 404On those architectures that support it, this enables binary 405compatibility with iBCS2 or SVR3 applications built for the same architecture. 406This is currently limited to the i386 and vax ports. 407.It Cd options COMPAT_OSF1 408On those architectures that support it, this enables binary 409compatibility with 410.Tn Digital 411.Ux 412.Po 413formerly 414.Tn OSF/1 415.Pc 416applications built for the same architecture. 417This is currently limited to the alpha port. 418.It Cd options COMPAT_NOMID 419Enable compatibility with 420.Xr a.out 5 421executables that lack a machine ID. 422This includes 423.Nx 0.8 Ns 's 424ZMAGIC format, and 386BSD and BSDI's 425QMAGIC, NMAGIC, and OMAGIC 426.Xr a.out 5 427formats. 428.It Cd options COMPAT_NETBSD32 429On those architectures that support it, this enables binary 430compatibility with 32-bit applications built for the same architecture. 431This is currently limited to the amd64 and sparc64 ports, and only 432applicable for 64-bit kernels. 433.It Cd options COMPAT_SVR4_32 434On those architectures that support it, this enables binary 435compatibility with 32-bit SVR4 applications built for the same architecture. 436This is currently limited to the sparc64 port, and only applicable for 43764-bit kernels. 438.It Cd options COMPAT_AOUT_M68K 439On m68k architectures which have switched to ELF, 440this enables binary compatibility with 441.Nx Ns Tn /m68k 442.Xr a.out 5 443executables on 444.Nx Ns Tn /m68k 445ELF kernels. 446This handles alignment incompatibility of m68k ABI between 447a.out and ELF which causes the structure padding differences. 448Currently only some system calls which use 449.Va struct stat 450are adjusted and some binaries which use 451.Xr sysctl 3 452to retrieve network details would not work properly. 453.It Cd options EMUL_NATIVEROOT=string 454Just like emulated binaries first try looking up files in 455an emulation root (e.g. 456.Pa /emul/linux ) 457before looking them up in real root, this option causes native 458binaries to first look up files in an "emulation" directory too. 459This can be useful to test an amd64 kernel on top of an i386 system 460before full migration: by unpacking the amd64 distribution in e.g. 461.Pa /emul/netbsd64 462and specifying that location as 463.Cd EMUL_NATIVEROOT , 464native amd64 binaries can be run while the root file system remains 465populated with i386 binaries. 466Beware of 467.Pa /dev 468incompatibilities between i386 and amd64 if you do this. 469.It Cd options EXEC_ELF_NOTELESS 470Run unidentified ELF binaries as 471.Nx 472binaries. 473This might be needed for very old 474.Nx 475ELF binaries on some archs. 476These old binaries didn't contain an appropriate 477.Li .note.netbsd.ident 478section, and thus can't be identified by the kernel as 479.Nx 480binaries otherwise. 481Beware - if this option is on, the kernel would run 482.Em any 483unknown ELF binaries as if they were 484.Nx 485binaries. 486.It Cd options P1003_1B_SEMAPHORE 487Includes kernel support for the standard C library 488.Pq libc 489functions that implement semaphores as specified in 490.St -p1003.1-96 . 491.El 492.Ss Debugging Options 493.Bl -ohang 494.It Cd options DDB 495Compiles in a kernel debugger for diagnosing kernel problems. 496See 497.Xr ddb 4 498for details. 499.Em NOTE : 500not available on all architectures. 501.It Cd options DDB_FROMCONSOLE=integer 502If set to non-zero, DDB may be entered by sending a break on a serial 503console or by a special key sequence on a graphics console. 504A value of "0" ignores console breaks or key sequences. 505If not explicitly specified, the default value is "1". 506Note that this sets the value of the 507.Em ddb.fromconsole 508.Xr sysctl 3 509variable which may be changed at run time -- see 510.Xr sysctl 8 511for details. 512.It Cd options DDB_HISTORY_SIZE=integer 513If this is non-zero, enable history editing in the kernel debugger 514and set the size of the history to this value. 515.It Cd options DDB_ONPANIC 516The default if not specified is 517.Dq 1 518- just enter into DDB. 519If set to 520.Dq 2 521the kernel will 522attempt to print out a stack trace before entering into DDB. 523If set to 524.Dq 0 525the kernel will attempt to print out a stack trace 526and reboot the system. 527If set to 528.Dq -1 529then neither a stack trace is printed or DDB entered - 530it is as if DDB were not compiled into the kernel. 531Note that this sets the value of the 532.Em ddb.onpanic 533.Xr sysctl 3 534variable which may be changed at run time -- see 535.Xr sysctl 8 536for details. 537.It Cd options DDB_COMMANDONENTER=string 538This option specify commands which will be executed on each entry to DDB. 539This sets the default value of the 540.Em ddb.commandonenter 541.Xr sysctl 3 542variable which may be changed at run time. 543.It Cd options DDB_BREAK_CHAR=integer 544This option overrides using break to enter the kernel debugger 545on the serial console. 546The value given is the ASCII value to be used instead. 547This is currently only supported by the com driver. 548.It Cd options DDB_VERBOSE_HELP 549This option adds more verbose descriptions to the 550.Em help 551command. 552.It Cd options KGDB 553Compiles in a remote kernel debugger stub for diagnosing kernel problems 554using the 555.Dq remote target 556feature of gdb. 557See 558.Xr gdb 1 559for details. 560.Em NOTE : 561not available on all architectures. 562.It Cd options KGDB_DEV 563Device number 564.Po 565as a 566.Dv dev_t 567.Pc 568of kgdb device. 569.It Cd options KGDB_DEVADDR 570Memory address of kgdb device. 571.It Cd options KGDB_DEVMODE 572Permissions of kgdb device. 573.It Cd options KGDB_DEVNAME 574Device name of kgdb device. 575.It Cd options KGDB_DEVRATE 576Baud rate of kgdb device. 577.It Cd makeoptions DEBUG="-g" 578The 579.Fl g 580flag causes 581.Pa netbsd.gdb 582to be built in addition to 583.Pa netbsd . 584.Pa netbsd.gdb 585is useful for debugging kernel crash dumps with gdb. 586See 587.Xr gdb 1 588for details. 589This also turns on 590.Em options DEBUG 591(which see). 592.It Cd options DEBUG 593Turns on miscellaneous kernel debugging. 594Since options are turned into preprocessor defines (see above), 595.Em options DEBUG 596is equivalent to doing a 597.Em #define DEBUG 598throughout the kernel. 599Much of the kernel has 600.Em #ifdef DEBUG 601conditionalized debugging code. 602Note that many parts of the kernel (typically device drivers) include their own 603.Em #ifdef XXX_DEBUG 604conditionals instead. 605This option also turns on certain other options, 606which may decrease system performance. 607.It Cd options DIAGNOSTIC 608Adds code to the kernel that does internal consistency checks. 609This code will cause the kernel to panic if corruption of internal data 610structures is detected. 611These checks can decrease performance up to 15%. 612.It Cd options LOCKDEBUG 613Adds code to the kernel to detect incorrect use of locking primitives 614(mutex, rwlock). 615This code will cause the kernel to check for dead lock conditions. 616It will also check for memory being freed to not contain initialised 617lock primitives. 618Functions for use in 619.Xr ddb 4 620to check lock chains etc. are also enabled. 621These checks are very expensive and can decrease performance on 622multi-processor machines by a factor of three. 623.It Cd options KSTACK_CHECK_MAGIC 624Check kernel stack usage and panic if stack overflow is detected. 625This check is performance sensitive because it scans stack on each context 626switch. 627.It Cd options KTRACE 628Add hooks for the system call tracing facility, which allows users to 629watch the system call invocation behavior of processes. 630See 631.Xr ktrace 1 632for details. 633.It Cd options MSGBUFSIZE=integer 634This option sets the size of the kernel message buffer. 635This buffer holds the kernel output of 636.Fn printf 637when not (yet) read by 638.Xr syslogd 8 . 639This is particularly useful when the system has crashed and you wish to lookup 640the kernel output from just before the crash. 641Also, since the autoconfig output becomes more and more verbose, 642it sometimes happens that the message buffer overflows before 643.Xr syslogd 8 644was able to read it. 645Note that not all systems are capable of obtaining a variable sized message 646buffer. 647There are also some systems on which memory contents are not preserved 648across reboots. 649.It Cd options MALLOCLOG 650Enables an event log for 651.Xr malloc 9 . 652Useful for tracking down 653.Dq Data modified on freelist 654and 655.Dq multiple free 656problems. 657.It Cd options MALLOCLOGSIZE=integer 658Defines the number of entries in the malloc log. 659Default is 100000 entries. 660.It Cd options KERNHIST 661Enables the kernel history logs, which create in-memory traces of 662various kernel activities. 663These logs can be displayed by using 664.Cm show kernhist 665from DDB. 666See the kernel source file 667.Pa sys/kern/kern_history.c 668for details. 669.It Cd options KERNHIST_PRINT 670Prints the kernel history logs on the system console as entries are added. 671Note that the output is 672.Em extremely 673voluminous, so this option is really only useful for debugging 674the very earliest parts of kernel initialization. 675.It Cd options UVMHIST 676Like 677.Em KERNHIST , 678it enables the UVM history logs. 679These logs can be displayed by using 680.Cm show kernhist 681from DDB. 682See the kernel source file 683.Pa sys/uvm/uvm_stat.c 684for details. 685.It Cd options UVMHIST_PRINT 686Like 687.Em UVMHIST , 688it prints the UVM history logs on the system console as entries are added. 689Note that the output is 690.Em extremely 691voluminous, so this option is really only useful for debugging 692the very earliest parts of kernel initialization. 693.El 694.Ss File Systems 695.Bl -ohang 696.It Cd file-system FFS 697Includes code implementing the Berkeley Fast File System 698.Po Em FFS Pc . 699Most machines need this if they are not running diskless. 700.It Cd file-system EXT2FS 701Includes code implementing the Second Extended File System 702.Po Em ext2 Pc , 703revision 0 and revision 1 with the 704.Em filetype , 705.Em sparse_super 706and 707.Em large_file 708options. 709This is the most commonly used file system on the Linux operating system, 710and is provided here for compatibility. 711Some of the specific features of 712.Em ext2 713like the "behavior on errors" are not implemented. 714See 715.Xr mount_ext2fs 8 716for details. 717.It Cd file-system LFS 718.Bq Em EXPERIMENTAL 719Include the Log-structured File System 720.Po Em LFS Pc . 721See 722.Xr mount_lfs 8 723and 724.Xr newfs_lfs 8 725for details. 726.It Cd file-system MFS 727Include the Memory File System 728.Po Em MFS Pc . 729This file system stores files in swappable memory, and produces 730notable performance improvements when it is used as the file store 731for 732.Pa /tmp 733and similar file systems. 734See 735.Xr mount_mfs 8 736for details. 737.It Cd file-system NFS 738Include the client side of the Network File System 739.Pq Tn NFS 740remote file sharing protocol. 741Although the bulk of the code implementing 742.Tn NFS 743is kernel based, several user level daemons are needed for it to work. 744See 745.Xr mount_nfs 8 746for details. 747.It Cd file-system CD9660 748Includes code for the 749.Tn ISO 7509660 + Rock Ridge file system, which is the standard file system on many 751.Tn CD-ROM 752discs. 753Useful primarily if you have a 754.Tn CD-ROM 755drive. 756See 757.Xr mount_cd9660 8 758for details. 759.It Cd file-system MSDOSFS 760Includes the 761.Tn MS-DOS 762FAT file system, which is reportedly still used 763by unfortunate people who have not heard about 764.Nx . 765Also implements the 766.Tn Windows 95 767extensions to the same, which permit the use of longer, mixed case 768file names. 769See 770.Xr mount_msdos 8 771and 772.Xr fsck_msdos 8 773for details. 774.It Cd file-system NTFS 775.Bq Em EXPERIMENTAL 776Includes code for the 777.Tn Microsoft Windows NT 778file system. 779See 780.Xr mount_ntfs 8 781for details. 782.It Cd file-system FDESC 783Includes code for a file system, conventionally mounted on 784.Pa /dev/fd , 785which permits access to the per-process file descriptor space via 786special files in the file system. 787See 788.Xr mount_fdesc 8 789for details. 790Note that this facility is redundant, and thus unneeded on most 791.Nx 792systems, since the 793.Xr fd 4 794pseudo-device driver already provides identical functionality. 795On most 796.Nx 797systems, instances of 798.Xr fd 4 799are mknoded under 800.Pa /dev/fd/ 801and on 802.Pa /dev/stdin , 803.Pa /dev/stdout , 804and 805.Pa /dev/stderr . 806.It Cd file-system KERNFS 807Includes code which permits the mounting of a special file system 808(normally mounted on 809.Pa /kern ) 810in which files representing various kernel variables and parameters 811may be found. 812See 813.Xr mount_kernfs 8 814for details. 815.It Cd file-system NULLFS 816Includes code for a loopback file system. 817This permits portions of the file hierarchy to be re-mounted in other places. 818The code really exists to provide an example of a stackable file system layer. 819See 820.Xr mount_null 8 821for details. 822.It Cd file-system OVERLAY 823Includes code for a file system filter. 824This permits the overlay file system to intercept all access to an underlying 825file system. 826This file system is intended to serve as an example of a stacking file 827system which has a need to interpose itself between an underlying file 828system and all other access. 829See 830.Xr mount_overlay 8 831for details. 832.It Cd file-system PROCFS 833Includes code for a special file system (conventionally mounted on 834.Pa /proc ) 835in which the process space becomes visible in the file system. 836Among 837other things, the memory spaces of processes running on the system are 838visible as files, and signals may be sent to processes by writing to 839.Pa ctl 840files in the procfs namespace. 841See 842.Xr mount_procfs 8 843for details. 844.It Cd file-system UDF 845.Bq Em EXPERIMENTAL 846Includes code for the UDF file system commonly found on CD and DVD 847media but also on USB sticks. 848Currently supports read and write access upto UDF 2.01 and somewhat limited 849write support for UDF 2.50. 850It is marked experimental since there is no 851.Xr fsck_udf 8 . 852See 853.Xr mount_udf 8 854for details. 855.It Cd file-system UMAPFS 856Includes a loopback file system in which user and group IDs may be 857remapped -- this can be useful when mounting alien file systems with 858different UIDs and GIDs than the local system. 859See 860.Xr mount_umap 8 861for details. 862.It Cd file-system UNION 863.Bq Em EXPERIMENTAL 864Includes code for the union file system, which permits directories to 865be mounted on top of each other in such a way that both file systems 866remain visible -- this permits tricks like allowing writing (and the 867deleting of files) on a read-only file system like a 868.Tn CD-ROM 869by mounting a local writable file system on top of the read-only file system. 870See 871.Xr mount_union 8 872for details. 873.It Cd file-system CODA 874.Bq Em EXPERIMENTAL 875Includes code for the Coda file system. 876Coda is a distributed file system like NFS and AFS. 877It is freely available, like NFS, but it functions much like AFS in being a 878.Dq stateful 879file system. 880Both Coda and AFS cache files on your local machine to improve performance. 881Then Coda goes a step further than AFS by letting you access the cached 882files when there is no available network, viz. disconnected laptops and 883network outages. 884In Coda, both the client and server are outside the kernel which makes 885them easier to experiment with. 886Coda is available for several UNIX and non-UNIX platforms. 887See 888.Lk http://www.coda.cs.cmu.edu 889for more details. 890.Em NOTE : 891You also need to enable the pseudo-device, vcoda, for the Coda 892file system to work. 893.It Cd file-system SMBFS 894.Bq Em EXPERIMENTAL 895Includes code for the SMB/CIFS file system. 896See 897.Xr mount_smbfs 8 898for details. 899.Em NOTE : 900You also need to enable the pseudo-device, nsmb, for the SMB 901file system to work. 902.It Cd file-system PTYFS 903.Bq Em EXPERIMENTAL 904Includes code for a special file system (normally mounted on 905.Pa /dev/pts ) 906in which pseudo-terminal slave devices become visible in the file system. 907See 908.Xr mount_ptyfs 8 909for details. 910.It Cd file-system TMPFS 911Includes code for the efficient memory file system, normally used over 912.Pa /tmp . 913See 914.Xr mount_tmpfs 8 915for details. 916.It Cd file-system PUFFS 917Includes kernel support for the pass-to-userspace framework file system. 918It can be used to implement file system functionality in userspace. 919See 920.Xr puffs 3 921for more details. 922This enables for example sshfs: 923.Xr mount_psshfs 8 . 924.El 925.Ss File System Options 926.Bl -ohang 927.It Cd options MAGICLINKS 928Enables the expansion of special strings 929.Po 930beginning with 931.Dq @ 932.Pc 933when traversing symbolic links. 934See 935.Xr symlink 7 936for a list of supported strings. 937Note that this option only controls the enabling of this feature 938by the kernel at boot-up. 939This feature can still be manipulated with the 940.Xr sysctl 8 941command regardless of the setting of this option. 942.It Cd options NFSSERVER 943Include the server side of the 944.Em NFS 945(Network File System) remote file sharing protocol. 946Although the bulk of the code implementing 947.Em NFS 948is kernel based, several user level daemons are needed for it to 949work. 950See 951.Xr mountd 8 952and 953.Xr nfsd 8 954for details. 955.It Cd options NVNODE=integer 956This option sets the size of the cache used by the name-to-inode translation 957routines, (a.k.a. the 958.Fn namei 959cache, though called by many other names in the kernel source). 960By default, this cache has 961.Dv NPROC 962(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 963A reasonable way to derive a value of 964.Dv NVNODE , 965should you notice a large number of namei cache misses with a tool such as 966.Xr systat 1 , 967is to examine your system's current computed value with 968.Xr sysctl 8 , 969(which calls this parameter "kern.maxvnodes") and to increase this value 970until either the namei cache hit rate improves or it is determined that 971your system does not benefit substantially from an increase in the size of 972the namei cache. 973.It Cd options NAMECACHE_ENTER_REVERSE 974Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 975as well as a normal one. 976Normally, this is already done for directory vnodes, to speed up the getcwd 977operation. 978This option will cause longer hash chains in the reverse cache, and thus 979slow down getcwd somewhat. 980However, it does make vnode -\*[Gt] path translations possible in some cases. 981For now, only useful if strict 982.Pa /proc/#/maps 983emulation for Linux binaries is required. 984.El 985.Ss Options for FFS/UFS File Systems 986.Bl -ohang 987.It Cd options WAPBL 988Enable 989.Dq Write Ahead Physical Block Logging file system journaling . 990This provides rapid file system consistency checking after a system outage. 991It also provides better general use performance over regular FFS. 992See also 993.Xr wapbl 4 . 994.It Cd options QUOTA 995Enables kernel support for traditional quotas in FFS. 996Traditional quotas store the quota information in external files and 997require 998.Xr quotacheck 8 999and 1000.Xr quotaon 8 1001at boot time. 1002Traditional quotas are limited to 32-bit sizes and are at this point 1003considered a legacy feature. 1004.It Cd options QUOTA2 1005Enables kernel support for in-volume quotas in FFS. 1006The quota information is file system metadata maintained by 1007.Xr fsck 8 1008and/or WAPBL journaling. 1009MFS volumes can also use 1010.Dv QUOTA2 1011quotas; see 1012.Xr mount_mfs 8 1013for more information. 1014.It Cd options FFS_EI 1015Enable 1016.Dq Endian-Independent 1017FFS support. 1018This allows a system to mount an FFS file system created for another 1019architecture, at a small performance cost for all FFS file systems. 1020See also 1021.Xr newfs 8 , 1022.Xr fsck_ffs 8 , 1023.Xr dumpfs 8 1024for file system byte order status and manipulation. 1025.It Cd options FFS_NO_SNAPSHOT 1026Disable support for the creation of file system internal snapshot 1027of FFS file systems. 1028Maybe useful for install media kernels, small memory systems and 1029embedded systems which don't require the snapshot support. 1030.It Cd options UFS_EXTATTR 1031Enable extended attribute support for UFS1 file systems. 1032.It Cd options UFS_DIRHASH 1033Increase lookup performance by maintaining in-core hash tables 1034for large directories. 1035.El 1036.Ss Options for the LFS File System 1037.Bl -ohang 1038.\" .It Cd options LFS_KERNEL_RFW 1039.\" There is no documentation for this. (XXX) 1040.\" .It Cd options LFS_QUOTA 1041.\" Enable traditional quota support for LFS. 1042.\" (It is not clear if this works.) 1043.\" .It Cd options LFS_QUOTA2 1044.\" Enable modernized 64-bit quota support for LFS. 1045.\" (This does not work yet.) 1046.It Cd options LFS_EI 1047Enable 1048.Dq Endian-Independent 1049LFS support. 1050This allows (at a small performance cost) mounting an LFS file system 1051created for another architecture. 1052.\" .It Cd options LFS_EXTATTR 1053.\" Enable extended attribute support for LFS. 1054.\" (It is not clear if this works.) 1055.It Cd options LFS_DIRHASH 1056Increase lookup performance by maintaining in-core hash tables 1057for large directories. 1058.El 1059.Ss Options for the ext2fs File System 1060.Bl -ohang 1061.It Cd options EXT2FS_SYSTEM_FLAGS 1062This option changes the behavior of the APPEND and IMMUTABLE flags 1063for a file on an 1064.Em ext2 1065file system. 1066Without this option, the superuser or owner of the file can 1067set and clear them. 1068With this option, only the superuser can set them, and 1069they can't be cleared if the securelevel is greater than 0. 1070See also 1071.Xr chflags 1 1072and 1073.Xr secmodel_securelevel 9 . 1074.El 1075.Ss Options for the NFS File System 1076.Bl -ohang 1077.It Cd options NFS_BOOT_BOOTP 1078Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1079information if NFS is used to mount the root file system. 1080See 1081.Xr diskless 8 1082for details. 1083.It Cd options NFS_BOOT_BOOTSTATIC 1084Enable use of static values defined as 1085.Dq NFS_BOOTSTATIC_MYIP , 1086.Dq NFS_BOOTSTATIC_GWIP , 1087.Dq NFS_BOOTSTATIC_SERVADDR , 1088and 1089.Dq NFS_BOOTSTATIC_SERVER 1090in kernel options to get configuration information 1091if NFS is used to mount the root file system. 1092.It Cd options NFS_BOOT_DHCP 1093Same as 1094.Dq NFS_BOOT_BOOTP , 1095but use the DHCP extensions to the 1096BOOTP protocol (RFC 1541). 1097.It Cd options NFS_BOOT_BOOTP_REQFILE 1098Specifies the string sent in the bp_file field of the BOOTP/DHCP 1099request packet. 1100.It Cd options NFS_BOOT_BOOTPARAM 1101Enable use of the BOOTPARAM protocol, consisting of RARP and 1102BOOTPARAM RPC, to get configuration information if NFS 1103is used to mount the root file system. 1104See 1105.Xr diskless 8 1106for details. 1107.It Cd options NFS_BOOT_RWSIZE=value 1108Set the initial NFS read and write sizes for diskless-boot requests. 1109The normal default is 8Kbytes. 1110This option provides a way to lower the value (e.g., to 1024 bytes) 1111as a workaround for buggy network interface cards or boot PROMs. 1112Once booted, the read and write request sizes can be increased by 1113remounting the file system. 1114See 1115.Xr mount_nfs 8 1116for details. 1117.It Cd options NFS_V2_ONLY 1118Reduce the size of the NFS client code by omitting code that's only required 1119for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1120servers. 1121.El 1122.Ss Buffer queue strategy options 1123The following options enable alternative buffer queue strategies. 1124.Bl -ohang 1125.It Cd options BUFQ_READPRIO 1126Enable experimental buffer queue strategy for disk I/O. 1127In the default strategy, outstanding disk requests are ordered by 1128sector number and sent to the disk, regardless of whether the 1129operation is a read or write; this option gives priority to issuing 1130read requests over write requests. 1131Although requests may therefore be issued out of sector-order, causing 1132more seeks and thus lower overall throughput, interactive system 1133responsiveness under heavy disk I/O load may be improved, as processes 1134blocking on disk reads are serviced sooner (file writes typically 1135don't cause applications to block). 1136The performance effect varies greatly depending on the hardware, drive 1137firmware, file system configuration, workload, and desired performance 1138trade-off. 1139Systems using drive write-cache (most modern IDE disks, by default) 1140are unlikely to benefit and may well suffer; such disks acknowledge 1141writes very quickly, and optimize them internally according to 1142physical layout. 1143Giving these disks as many requests to work with as possible (the 1144standard strategy) will typically produce the best results, especially 1145if the drive has a large cache; the drive will silently complete 1146writes from cache as it seeks for reads. 1147Disks that support a large number of concurrent tagged requests (SCSI 1148disks and many hardware RAID controllers) expose this internal 1149scheduling with tagged responses, and don't block for reads; such 1150disks may not see a noticeable difference with either strategy. 1151However, if IDE disks are run with write-cache disabled for safety, 1152writes are not acknowledged until actually completed, and only one 1153request can be outstanding; a large number of small writes in one 1154locality can keep the disk busy, starving reads elsewhere on the disk. 1155Such systems are likely to see the most benefit from this option. 1156Finally, the performance interaction of this option with ffs soft 1157dependencies can be subtle, as that mechanism can drastically alter 1158the workload for file system metadata writes. 1159.It Cd options BUFQ_PRIOCSCAN 1160Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1161.It Cd options NEW_BUFQ_STRATEGY 1162Synonym of 1163.Em BUFQ_READPRIO . 1164.El 1165.Ss Miscellaneous Options 1166.Bl -ohang 1167.It Cd options CPU_UCODE 1168Support cpu microcode loading via 1169.Xr cpuctl 8 . 1170.It Cd options MEMORY_DISK_DYNAMIC 1171This option makes the 1172.Xr md 4 1173.Tn RAM 1174disk size dynamically sized. 1175It is incompatible with 1176.Xr mdsetimage 8 . 1177.It Cd options MEMORY_DISK_HOOKS 1178This option allows for some machine dependent functions to be called when 1179the 1180.Xr md 4 1181.Tn RAM 1182disk driver is configured. 1183This can result in automatically loading a 1184.Tn RAM 1185disk from floppy on open (among other things). 1186.It Cd options MEMORY_DISK_IS_ROOT 1187Forces the 1188.Xr md 4 1189.Tn RAM 1190disk to be the root device. 1191This can only be overridden when 1192the kernel is booted in the 'ask-for-root' mode. 1193.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1194Allocates the given number of 512 byte blocks as memory for the 1195.Xr md 4 1196.Tn RAM 1197disk, to be populated with 1198.Xr mdsetimage 8 . 1199.It Cd options MEMORY_DISK_SERVER=0 1200Do not include the interface to a userland memory disk server process. 1201Per default, this option is set to 1, including the support code. 1202Useful for install media kernels. 1203.It Cd options MEMORY_DISK_RBFLAGS=value 1204This option sets the 1205.Xr reboot 2 1206flags used when booting with a memory disk as root file system. 1207Possible values include 1208.Dv RB_AUTOBOOT 1209(boot in the usual fashion - default value), and 1210.Dv RB_SINGLE 1211(boot in single-user mode). 1212.It Cd options MODULAR 1213Enables the framework for kernel modules (see 1214.Xr module 7 ) . 1215.It Cd options VND_COMPRESSION 1216Enables the 1217.Xr vnd 4 1218driver to also handle compressed images. 1219See 1220.Xr vndcompress 1 , 1221.Xr vnd 4 1222and 1223.Xr vnconfig 8 1224for more information. 1225.It Cd options SPLDEBUG 1226Help the kernel programmer find bugs related to the interrupt priority 1227level. 1228When 1229.Fn spllower 1230or 1231.Fn splraise 1232changes the current CPU's interrupt priority level to or from 1233.Dv IPL_HIGH , 1234record a backtrace. 1235Read 1236.Xr return_address 9 1237for caveats about collecting backtraces. 1238This feature is experimental, and it is only available on i386. 1239See 1240.Pa sys/kern/subr_spldebug.c . 1241.It Cd options TFTPROOT 1242Download the root memory disk through TFTP at root mount time. 1243This enables the use of a root 1244.Tn RAM 1245disk without requiring it to be embedded in the kernel using 1246.Xr mdsetimage 8 . 1247The 1248.Tn RAM 1249disk name is obtained using DHCP's filename parameter. 1250This option requires 1251.Em MEMORY_DISK_HOOKS , 1252.Em MEMORY_DISK_DYNAMIC , 1253and 1254.Em MEMORY_DISK_IS_ROOT . 1255It is incompatible with 1256.Em MEMORY_DISK_ROOT_SIZE . 1257.It Cd options MALLOC_NOINLINE 1258Time critical fixed size memory allocation is performed with 1259.Fn MALLOC 1260and 1261.Fn FREE . 1262Normally these expand to inline code, but with 1263.Em MALLOC_NOINLINE 1264these call the normal 1265.Fn malloc 1266and 1267.Fn free 1268functions. 1269Useful for install media kernels, small memory systems and embedded systems. 1270.It Cd options HZ=integer 1271On ports that support it, set the system clock frequency (see 1272.Xr hz 9 ) 1273to the supplied value. 1274Handle with care. 1275.It Cd options NTP 1276Turns on in-kernel precision timekeeping support used by software 1277implementing 1278.Em NTP 1279(Network Time Protocol, RFC 1305). 1280The 1281.Em NTP 1282option adds an in-kernel Phase-Locked Loop (PLL) for normal 1283.Em NTP 1284operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1285operation. 1286.Xr ntpd 8 1287will employ a user-level PLL when kernel support is unavailable, 1288but the in-kernel version has lower latency and more precision, and 1289so typically keeps much better time. 1290.Pp 1291The interface to the kernel 1292.Em NTP 1293support is provided by the 1294.Xr ntp_adjtime 2 1295and 1296.Xr ntp_gettime 2 1297system calls, which are intended for use by 1298.Xr ntpd 8 1299and are enabled by the option. 1300On systems with sub-microsecond resolution timers, or where (HZ/100000) 1301is not an integer, the 1302.Em NTP 1303option also enables extended-precision arithmetic to keep track of 1304fractional clock ticks at NTP time-format precision. 1305.It Cd options PPS_SYNC 1306This option enables a kernel serial line discipline for receiving time 1307phase signals from an external reference clock such as a radio clock. 1308.Po 1309The 1310.Em NTP 1311option (which see) must be on if the 1312.Em PPS_SYNC 1313option is used 1314.Pc . 1315Some reference clocks generate a Pulse Per Second (PPS) signal in 1316phase with their time source. 1317The 1318.Em PPS 1319line discipline receives this signal on either the data leads 1320or the DCD control lead of a serial port. 1321.Pp 1322.Em NTP 1323uses the PPS signal to discipline the local clock oscillator to a high 1324degree of precision (typically less than 50 microseconds in time and 13250.1 ppm in accuracy). 1326.Em PPS 1327can also generate a serial output pulse when the system receives a PPS 1328interrupt. 1329This can be used to measure the system interrupt latency and thus calibrate 1330.Em NTP 1331to account for it. 1332Using 1333.Em PPS 1334usually requires a gadget box 1335to convert from 1336.Tn TTL 1337to 1338.Tn RS-232 1339signal levels. 1340The gadget box and PPS are described in more detail in the HTML documentation 1341for 1342.Xr ntpd 8 1343in 1344.Pa /usr/share/doc/html/ntp . 1345.Pp 1346.Nx 1347currently supports this option in 1348.Xr com 4 1349and 1350.Xr zsc 4 . 1351.It Cd options SETUIDSCRIPTS 1352Allows scripts with the setuid bit set to execute as the effective 1353user rather than the real user, just like binary executables. 1354.Pp 1355.Em NOTE : 1356Using this option will also enable 1357.Em options FDSCRIPTS 1358.It Cd options FDSCRIPTS 1359Allows execution of scripts with the execute bit set, but not the 1360read bit, by opening the file and passing the file descriptor to 1361the shell, rather than the filename. 1362.Pp 1363.Em NOTE : 1364Execute only (non-readable) scripts will have 1365.Va argv[0] 1366set to 1367.Pa /dev/fd/* . 1368What this option allows as far as security is 1369concerned, is the ability to safely ensure that the correct script 1370is run by the interpreter, as it is passed as an already open file. 1371.It Cd options RTC_OFFSET=integer 1372The kernel (and typically the hardware battery backed-up clock on 1373those machines that have one) keeps time in 1374.Em UTC 1375(Universal Coordinated Time, once known as 1376.Em GMT , 1377or Greenwich Mean Time) 1378and not in the time of the local time zone. 1379The 1380.Em RTC_OFFSET 1381option is used on some ports (such as the i386) to tell the kernel 1382that the hardware clock is offset from 1383.Em UTC 1384by the specified number of minutes. 1385This is typically used when a machine boots several operating 1386systems and one of them wants the hardware clock to run in the 1387local time zone and not in 1388.Em UTC , 1389e.g. 1390.Em RTC_OFFSET=300 1391means 1392the hardware clock is set to US Eastern Time (300 minutes behind 1393.Em UTC ) , 1394and not 1395.Em UTC . 1396(Note: 1397.Em RTC_OFFSET 1398is used to initialize a kernel variable named 1399.Va rtc_offset 1400which is the source actually used to determine the clock offset, and 1401which may be accessed via the kern.rtc_offset sysctl variable. 1402See 1403.Xr sysctl 8 1404and 1405.Xr sysctl 3 1406for details. 1407Since the kernel clock is initialized from the hardware clock very 1408early in the boot process, it is not possible to meaningfully change 1409.Va rtc_offset 1410in system initialization scripts. 1411Changing this value currently may only be done at kernel compile 1412time or by patching the kernel and rebooting). 1413.Pp 1414.Em NOTE : 1415Unfortunately, in many cases where the hardware clock 1416is kept in local time, it is adjusted for Daylight Savings 1417Time; this means that attempting to use 1418.Em RTC_OFFSET 1419to let 1420.Nx 1421coexist with such an operating system, like Windows, 1422would necessitate changing 1423.Em RTC_OFFSET 1424twice a year. 1425As such, this solution is imperfect. 1426.It Cd options KMEMSTATS 1427The kernel memory allocator, 1428.Xr malloc 9 , 1429will keep statistics on its performance if this option is enabled. 1430Unfortunately, this option therefore essentially disables the 1431.Fn MALLOC 1432and 1433.Fn FREE 1434forms of the memory allocator, which are used to enhance the performance 1435of certain critical sections of code in the kernel. 1436This option therefore can lead to a significant decrease in the 1437performance of certain code in the kernel if enabled. 1438Examples of such code include the 1439.Fn namei 1440routine, the 1441.Xr ccd 4 1442driver, 1443and much of the networking code. 1444.It Cd options MAXUPRC=integer 1445Sets the soft 1446.Dv RLIMIT_NPROC 1447resource limit, which specifies the maximum number of simultaneous 1448processes a user is permitted to run, for process 0; 1449this value is inherited by its child processes. 1450It defaults to 1451.Em CHILD_MAX , 1452which is currently defined to be 160. 1453Setting 1454.Em MAXUPRC 1455to a value less than 1456.Em CHILD_MAX 1457is not permitted, as this would result in a violation of the semantics of 1458.St -p1003.1-90 . 1459.It Cd options NOFILE=integer 1460Sets the soft 1461.Dv RLIMIT_NOFILE 1462resource limit, which specifies the maximum number of open 1463file descriptors for each process; 1464this value is inherited by its child processes. 1465It defaults to 1466.Em OPEN_MAX , 1467which is currently defined to be 64. 1468.It Cd options MAXFILES=integer 1469Sets the default value of the 1470.Em kern.maxfiles 1471sysctl variable, which indicates the maximum number of files that may 1472be open in the system. 1473.It Cd options DEFCORENAME=string 1474Sets the default value of the 1475.Em kern.defcorename 1476sysctl variable, otherwise it is set to 1477.Nm %n.core . 1478See 1479.Xr sysctl 8 1480and 1481.Xr sysctl 3 1482for details. 1483.It Cd options RASOPS_CLIPPING 1484Enables clipping within the 1485.Nm rasops 1486raster-console output system. 1487.Em NOTE : 1488only available on architectures that use 1489.Nm rasops 1490for console output. 1491.It Cd options RASOPS_SMALL 1492Removes optimized character writing code from the 1493.Nm rasops 1494raster-console output system. 1495.Em NOTE : 1496only available on architectures that use 1497.Nm rasops 1498for console output. 1499.It Cd options INCLUDE_CONFIG_FILE 1500Embeds the kernel config file used to define the kernel in the kernel 1501binary itself. 1502The embedded data also includes any files directly included by the config 1503file itself, e.g. 1504.Pa GENERIC.local 1505or 1506.Pa std.$MACHINE . 1507The embedded config file can be extracted from the resulting kernel with 1508.Xr config 1 1509.Fl x , 1510or by the following command: 1511.Bd -literal -offset indent 1512strings netbsd | sed -n 's/^_CFG_//p' | unvis 1513.Ed 1514.It Cd options INCLUDE_JUST_CONFIG 1515Similar to the above option, but includes just the actual config file, 1516not any included files. 1517.It Cd options PIPE_SOCKETPAIR 1518Use slower, but smaller socketpair(2)-based pipe implementation instead 1519of default faster, but bigger one. 1520Primarily useful for installation kernels. 1521.It Cd options USERCONF 1522Compiles in the in-kernel device configuration manager. 1523See 1524.Xr userconf 4 1525for details. 1526.It Cd options PERFCTRS 1527Compiles in kernel support for CPU performance-monitoring counters. 1528See 1529.Xr pmc 1 1530for details. 1531.Em NOTE : 1532not available on all architectures. 1533.It Cd options SYSCALL_STATS 1534Count the number of times each system call number is called. 1535The values can be read through the sysctl interface and displayed using 1536.Xr systat 1 . 1537.Em NOTE : 1538not yet available on all architectures. 1539.It Cd options SYSCALL_TIMES 1540Count the time spent (using 1541.Fn cpu_counter32 ) 1542in each system call. 1543.Em NOTE : 1544Using this option will also enable 1545.Cd options SYSCALL_STATS . 1546.It Cd options SYSCALL_TIMES_HASCOUNTER 1547Force use of 1548.Fn cpu_counter32 1549even if 1550.Fn cpu_hascounter 1551reports false. 1552Useful for systems where the cycle counter doesn't run at a constant rate 1553(e.g. Soekris boxes). 1554.It Cd options XSERVER_DDB 1555A supplement to XSERVER that adds support for entering 1556.Xr ddb 4 1557while in 1558.Tn X11 . 1559.It Cd options FILEASSOC 1560Support for 1561.Xr fileassoc 9 . 1562.It Cd options FILEASSOC_NHOOKS=integer 1563Number of storage slots per file for 1564.Xr fileassoc 9 . 1565Default is 4. 1566.El 1567.Ss Networking Options 1568.Bl -ohang 1569.It Cd options GATEWAY 1570Enables 1571.Em IPFORWARDING 1572(which see) 1573and (on most ports) increases the size of 1574.Em NMBCLUSTERS 1575(which see). 1576In general, 1577.Em GATEWAY 1578is used to indicate that a system should act as a router, and 1579.Em IPFORWARDING 1580is not invoked directly. 1581(Note that 1582.Em GATEWAY 1583has no impact on protocols other than 1584.Tn IP , 1585such as 1586.Tn CLNP ) . 1587.Em GATEWAY 1588option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1589.It Cd options ICMPPRINTFS 1590The 1591.Em ICMPPRINTFS 1592option will enable debugging information to be printed about 1593the 1594.Xr icmp 4 1595protocol. 1596.It Cd options IPFORWARDING=value 1597If 1598.Em value 1599is 1 this enables IP routing behavior. 1600If 1601.Em value 1602is 0 (the default), it disables it. 1603The 1604.Em GATEWAY 1605option sets this to 1 automatically. 1606With this option enabled, the machine will forward IP datagrams destined 1607for other machines between its interfaces. 1608Note that even without this option, the kernel will 1609still forward some packets (such as source routed packets) -- removing 1610.Em GATEWAY 1611and 1612.Em IPFORWARDING 1613is insufficient to stop all routing through a bastion host on a 1614firewall -- source routing is controlled independently. 1615To turn off source routing, use 1616.Em options IPFORWSRCRT=0 1617(which see). 1618Note that IP forwarding may be turned on and off independently of the 1619setting of the 1620.Em IPFORWARDING 1621option through the use of the 1622.Em net.inet.ip.forwarding 1623sysctl variable. 1624If 1625.Em net.inet.ip.forwarding 1626is 1, IP forwarding is on. 1627See 1628.Xr sysctl 8 1629and 1630.Xr sysctl 3 1631for details. 1632.It Cd options IPFORWSRCRT=value 1633If 1634.Em value 1635is set to zero, source routing of IP datagrams is turned off. 1636If 1637.Em value 1638is set to one (the default) or the option is absent, source routed IP 1639datagrams are forwarded by the machine. 1640Note that source routing of IP packets may be turned on and off 1641independently of the setting of the 1642.Em IPFORWSRCRT 1643option through the use of the 1644.Em net.inet.ip.forwsrcrt 1645sysctl variable. 1646If 1647.Em net.inet.ip.forwsrcrt 1648is 1, forwarding of source routed IP datagrams is on. 1649See 1650.Xr sysctl 8 1651and 1652.Xr sysctl 3 1653for details. 1654.It Cd options IFA_STATS 1655Tells the kernel to maintain per-address statistics on bytes sent 1656and received over (currently) Internet and AppleTalk addresses. 1657.\"This can be a fairly expensive operation, so you probably want to 1658.\"keep this disabled. 1659The option is not recommended as it degrades system stability. 1660.It Cd options IFQ_MAXLEN=value 1661Increases the allowed size of the network interface packet queues. 1662The default queue size is 50 packets, and you do not normally need 1663to increase it. 1664.It Cd options IPSELSRC 1665Includes support for source-address selection policies. 1666See 1667.Xr in_getifa 9 . 1668.It Cd options MROUTING 1669Includes support for IP multicast routers. 1670You certainly want 1671.Em INET 1672with this. 1673Multicast routing is controlled by the 1674.Xr mrouted 8 1675daemon. 1676See also option 1677.Cd PIM . 1678.It Cd options PIM 1679Includes support for Protocol Independent Multicast (PIM) routing. 1680You need 1681.Em MROUTING 1682and 1683.Em INET 1684with this. 1685Software using this can be found e.g. in 1686.Pa pkgsrc/net/xorp . 1687.It Cd options INET 1688Includes support for the 1689.Tn TCP/IP 1690protocol stack. 1691You almost certainly want this. 1692See 1693.Xr inet 4 1694for details. 1695.It Cd options INET6 1696Includes support for the 1697.Tn IPv6 1698protocol stack. 1699See 1700.Xr inet6 4 1701for details. 1702Unlike 1703.Em INET , 1704.Em INET6 1705enables multicast routing code as well. 1706This option requires 1707.Em INET 1708at this moment, but it should not. 1709.It Cd options ND6_DEBUG 1710The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1711for debugging IPv6 neighbor discovery protocol handling. 1712See 1713.Xr sysctl 3 1714for details. 1715.It Cd options IPSEC 1716Includes support for the 1717.Tn IPsec 1718protocol, using the implementation derived from 1719.Ox , 1720relying on 1721.Xr opencrypto 9 1722to carry out cryptographic operations. 1723See 1724.Xr fast_ipsec 4 1725for details. 1726.It Cd options IPSEC_DEBUG 1727Enables debugging code in 1728.Tn IPsec 1729stack. 1730See 1731.Xr ipsec 4 1732for details. 1733The 1734.Cd IPSEC 1735option includes support for 1736.Tn IPsec 1737Network Address Translator traversal (NAT-T), as described in RFCs 3947 1738and 3948. 1739This feature might be patent-encumbered in some countries. 1740.It Cd options ALTQ 1741Enabled ALTQ (Alternate Queueing). 1742For simple rate-limiting, use 1743.Xr tbrconfig 8 1744to set up the interface transmission rate. 1745To use queueing disciplines, their appropriate kernel options should also 1746be defined (documented below). 1747Queueing disciplines are managed by 1748.Xr altqd 8 . 1749See 1750.Xr altq 9 1751for details. 1752.It Cd options ALTQ_HFSC 1753Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1754module. 1755HFSC supports both link-sharing and guaranteed real-time services. 1756HFSC employs a service curve based QoS model, and its unique feature 1757is an ability to decouple delay and bandwidth allocation. 1758Requires 1759.Em ALTQ_RED 1760to use the RED queueing discipline on HFSC classes, or 1761.Em ALTQ_RIO 1762to use the RIO queueing discipline on HFSC classes. 1763This option assumes 1764.Em ALTQ . 1765.It Cd options ALTQ_PRIQ 1766Include support for ALTQ-implemented PRIQ (Priority Queueing). 1767PRIQ implements a simple priority-based queueing discipline. 1768A higher priority class is always served first. 1769Requires 1770.Em ALTQ_RED 1771to use the RED queueing discipline on HFSC classes, or 1772.Em ALTQ_RIO 1773to use the RIO queueing discipline on HFSC classes. 1774This option assumes 1775.Em ALTQ . 1776.It Cd options ALTQ_WFQ 1777Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1778WFQ implements a weighted-round robin scheduler for a set of queues. 1779A weight can be assigned to each queue to give a different proportion 1780of the link capacity. 1781A hash function is used to map a flow to one of a set of queues. 1782This option assumes 1783.Em ALTQ . 1784.It Cd options ALTQ_FIFOQ 1785Include support for ALTQ-implemented FIFO queueing. 1786FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1787This option assumes 1788.Em ALTQ . 1789.It Cd options ALTQ_RIO 1790Include support for ALTQ-implemented RIO (RED with In/Out). 1791The original RIO has 2 sets of RED parameters; one for in-profile 1792packets and the other for out-of-profile packets. 1793At the ingress of the network, profile meters tag packets as IN or 1794OUT based on contracted profiles for customers. 1795Inside the network, IN packets receive preferential treatment by 1796the RIO dropper. 1797ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1798PHB of DiffServ (RFC 2597). 1799This option assumes 1800.Em ALTQ . 1801.It Cd options ALTQ_BLUE 1802Include support for ALTQ-implemented Blue buffer management. 1803Blue is another active buffer management mechanism. 1804This option assumes 1805.Em ALTQ . 1806.It Cd options ALTQ_FLOWVALVE 1807Include support for ALTQ-implemented Flowvalve. 1808Flowvalve is a simple implementation of a RED penalty box that identifies 1809and punishes misbehaving flows. 1810This option requires 1811.Em ALTQ_RED 1812and assumes 1813.Em ALTQ . 1814.It Cd options ALTQ_CDNR 1815Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1816packet marking/manipulation. 1817Traffic conditioners are components to meter, mark, or drop incoming 1818packets according to some rules. 1819As opposed to queueing disciplines, traffic conditioners handle incoming 1820packets at an input interface. 1821This option assumes 1822.Em ALTQ . 1823.It Cd options ALTQ_NOPCC 1824Disables use of processor cycle counter to measure time in ALTQ. 1825This option should be defined for a non-Pentium i386 CPU which does not 1826have TSC, SMP (per-CPU counters are not in sync), or power management 1827which affects processor cycle counter. 1828This option assumes 1829.Em ALTQ . 1830.It Cd options ALTQ_IPSEC 1831Include support for IPsec in IPv4 ALTQ. 1832This option assumes 1833.Em ALTQ . 1834.It Cd options ALTQ_JOBS 1835Include support for ALTQ-implemented JoBS (Joint Buffer Management 1836and Scheduling). 1837This option assumes 1838.Em ALTQ . 1839.It Cd options ALTQ_AFMAP 1840Include support for an undocumented ALTQ feature that is used to map an IP 1841flow to an ATM VC (Virtual Circuit). 1842This option assumes 1843.Em ALTQ . 1844.It Cd options ALTQ_LOCALQ 1845Include support for ALTQ-implemented local queues. 1846Its practical use is undefined. 1847Assumes 1848.Em ALTQ . 1849.It Cd options SUBNETSARELOCAL 1850Sets default value for net.inet.ip.subnetsarelocal variable, which 1851controls whether non-directly-connected subnets of connected networks 1852are considered "local" for purposes of choosing the MSS for a TCP 1853connection. 1854This is mostly present for historic reasons and completely irrelevant if 1855you enable Path MTU discovery. 1856.It Cd options HOSTZEROBROADCAST 1857Sets default value for net.inet.ip.hostzerobroadcast variable, which 1858controls whether the zeroth host address of each connected subnet is 1859also considered a broadcast address. 1860Default value is "1", for compatibility with old systems; if this is 1861set to zero on all hosts on a subnet, you should be able to fit an extra 1862host per subnet on the 1863".0" address. 1864.It Cd options MCLSHIFT=value 1865This option is the base-2 logarithm of the size of mbuf clusters. 1866The 1867.Bx 1868networking stack keeps network packets in a linked 1869list, or chain, of kernel buffer objects called mbufs. 1870The system provides larger mbuf clusters as an optimization for 1871large packets, instead of using long chains for large packets. 1872The mbuf cluster size, 1873or 1874.Em MCLBYTES , 1875must be a power of two, and is computed as two raised to the power 1876.Em MCLSHIFT . 1877On systems with Ethernet network adapters, 1878.Em MCLSHIFT 1879is often set to 11, giving 2048-byte mbuf clusters, large enough to 1880hold a 1500-byte 1881.Tn Ethernet 1882frame in a single cluster. 1883Systems with network interfaces supporting larger frame sizes like 1884.Tn ATM , 1885.Tn FDDI , 1886or 1887.Tn HIPPI 1888may perform better with 1889.Em MCLSHIFT 1890set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1891respectively. 1892.It Cd options ISO,TPIP 1893Include support for the ubiquitous 1894.Tn OSI 1895protocol stack. 1896See 1897.Xr iso 4 1898for details. 1899This option assumes 1900.Em INET . 1901.It Cd options EON 1902Include support for tunneling 1903.Tn OSI 1904protocols over 1905.Tn IP . 1906Known to be broken, or at least very fragile, and undocumented. 1907.It Cd options NETATALK 1908Include support for the 1909.Tn AppleTalk 1910protocol stack. 1911The kernel provides provision for the 1912.Em Datagram Delivery Protocol 1913(DDP), providing SOCK_DGRAM support and 1914.Tn AppleTalk 1915routing. 1916This stack is used by the 1917.Em NETATALK 1918package, which adds support for 1919.Tn AppleTalk 1920server services via user libraries and applications. 1921.It Cd options BLUETOOTH 1922Include support for the 1923.Tn Bluetooth 1924protocol stack. 1925See 1926.Xr bluetooth 4 1927for details. 1928.It Cd options IPNOPRIVPORTS 1929Normally, only root can bind a socket descriptor to a so-called 1930.Dq privileged 1931.Tn TCP 1932port, that is, a port number in the range 0-1023. 1933This option eliminates those checks from the kernel. 1934This can be useful if there is a desire to allow daemons without 1935privileges to bind those ports, e.g., on firewalls. 1936The security tradeoffs in doing this are subtle. 1937This option should only be used by experts. 1938.It Cd options TCP_COMPAT_42 1939.Tn TCP 1940bug compatibility with 1941.Bx 4.2 . 1942In 1943.Bx 4.2 , 1944.Tn TCP 1945sequence numbers were 32-bit signed values. 1946Modern implementations of TCP use unsigned values. 1947This option clamps the initial sequence number to start in 1948the range 2^31 rather than the full unsigned range of 2^32. 1949Also, under 1950.Bx 4.2 , 1951keepalive packets must contain at least one byte or else 1952the remote end would not respond. 1953.It Cd options TCP_DEBUG 1954Record the last 1955.Em TCP_NDEBUG 1956TCP packets with SO_DEBUG set, and decode to the console if 1957.Em tcpconsdebug 1958is set. 1959.It Cd options TCP_NDEBUG 1960Number of packets to record for 1961.Em TCP_DEBUG . 1962Defaults to 100. 1963.It Cd options TCP_SENDSPACE=value 1964.It Cd options TCP_RECVSPACE=value 1965These options set the max TCP window size to other sizes than the default. 1966The TCP window sizes can be altered via 1967.Xr sysctl 8 1968as well. 1969.It Cd options TCP_INIT_WIN=value 1970This option sets the initial TCP window size for non-local connections, 1971which is used when the transmission starts. 1972The default size is 1, but if the machine should act more aggressively, 1973the initial size can be set to some other value. 1974The initial TCP window size can be set via 1975.Xr sysctl 8 1976as well. 1977.It Cd options IPFILTER_LOG 1978This option, in conjunction with 1979.Em pseudo-device ipfilter , 1980enables logging of IP packets using IP-Filter. 1981.It Cd options IPFILTER_LOOKUP 1982This option enables the 1983IP-Filter 1984.Xr ippool 8 1985functionality to be enabled. 1986.It Cd options IPFILTER_COMPAT 1987This option enables older IP-Filter binaries to work. 1988.It Cd options IPFILTER_DEFAULT_BLOCK 1989This option sets the default policy of IP-Filter. 1990If it is set, IP-Filter will block packets by default. 1991.It Cd options BRIDGE_IPF 1992This option causes 1993.Em bridge 1994devices to use the IP and/or IPv6 filtering hooks, forming 1995a link-layer filter that uses protocol-layer rules. 1996This option assumes the presence of 1997.Em pseudo-device ipfilter . 1998.It Cd options MBUFTRACE 1999This option can help track down mbuf leaks. 2000When enabled, mbufs are tagged with the devices and protocols using them, 2001which slightly decreases network performance. 2002This additional information can be viewed with 2003.Xr netstat 1 : 2004.Dl Ic netstat Fl mssv 2005Not all devices or protocols support this option. 2006.El 2007.Ss Sysctl Related Options 2008.Bl -ohang 2009.It Cd options SYSCTL_DISALLOW_CREATE 2010Disallows the creation or deletion of nodes from the sysctl tree, as 2011well as the assigning of descriptions to nodes that lack them, by any 2012process. 2013These operations are still available to kernel sub-systems, including 2014loadable kernel modules. 2015.It Cd options SYSCTL_DISALLOW_KWRITE 2016Prevents processes from adding nodes to the sysctl tree that make 2017existing kernel memory areas writable. 2018Sections of kernel memory can still be read and new nodes that own 2019their own data may still be writable. 2020.It Cd options SYSCTL_DEBUG_SETUP 2021Causes the SYSCTL_SETUP routines to print a brief message when they 2022are invoked. 2023This is merely meant as an aid in determining the order in which 2024sections of the tree are created. 2025.It Cd options SYSCTL_DEBUG_CREATE 2026Prints a message each time 2027.Fn sysctl_create , 2028the function that adds nodes to the tree, is called. 2029.It Cd options SYSCTL_INCLUDE_DESCR 2030Causes the kernel to include short, human readable descriptions for 2031nodes in the sysctl tree. 2032The descriptions can be retrieved programmatically (see 2033.Xr sysctl 3 ) , 2034or by the sysctl binary itself (see 2035.Xr sysctl 8 ) . 2036The descriptions are meant to give an indication of the purpose and/or 2037effects of a given node's value, not replace the documentation for the 2038given subsystem as a whole. 2039.El 2040.Ss System V IPC Options 2041.Bl -ohang 2042.It Cd options SYSVMSG 2043Includes support for 2044.At V 2045style message queues. 2046See 2047.Xr msgctl 2 , 2048.Xr msgget 2 , 2049.Xr msgrcv 2 , 2050.Xr msgsnd 2 . 2051.It Cd options SYSVSEM 2052Includes support for 2053.At V 2054style semaphores. 2055See 2056.Xr semctl 2 , 2057.Xr semget 2 , 2058.Xr semop 2 . 2059.It Cd options SEMMNI=value 2060Sets the number of 2061.At V 2062style semaphore identifiers. 2063The GENERIC config file for your port will have the default. 2064.It Cd options SEMMNS=value 2065Sets the number of 2066.At V 2067style semaphores in the system. 2068The GENERIC config file for your port will have the default. 2069.It Cd options SEMUME=value 2070Sets the maximum number of undo entries per process for 2071.At V 2072style semaphores. 2073The GENERIC config file for your port will have the default. 2074.It Cd options SEMMNU=value 2075Sets the number of undo structures in the system for 2076.At V 2077style semaphores. 2078The GENERIC config file for your port will have the default. 2079.It Cd options SYSVSHM 2080Includes support for 2081.At V 2082style shared memory. 2083See 2084.Xr shmat 2 , 2085.Xr shmctl 2 , 2086.Xr shmdt 2 , 2087.Xr shmget 2 . 2088.It Cd options SHMMAXPGS=value 2089Sets the maximum number of 2090.At V 2091style shared memory pages that are available through the 2092.Xr shmget 2 2093system call. 2094Default value is 1024 on most ports. 2095See 2096.Pa /usr/include/machine/vmparam.h 2097for the default. 2098.El 2099.Ss VM Related Options 2100.Bl -ohang 2101.It Cd options NMBCLUSTERS=value 2102The number of mbuf clusters the kernel supports. 2103Mbuf clusters are MCLBYTES in size (usually 2k). 2104This is used to compute the size of the kernel VM map 2105.Em mb_map , 2106which maps mbuf clusters. 2107Default on most ports is 1024 (2048 with 2108.Dq options GATEWAY 2109). 2110See 2111.Pa /usr/include/machine/param.h 2112for exact default information. 2113Increase this value if you get 2114.Dq mclpool limit reached 2115messages. 2116.It Cd options NKMEMPAGES=value 2117.It Cd options NKMEMPAGES_MIN=value 2118.It Cd options NKMEMPAGES_MAX=value 2119Size of kernel VM map 2120.Em kmem_map , 2121in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2122from the 2123.Xr sysctl 8 2124variable 2125.Em hw.pagesize 2126). 2127This VM map is used to map the kernel malloc arena. 2128The kernel attempts to auto-size this map based on the amount of 2129physical memory in the system. 2130Platform-specific code may place bounds on this computed size, 2131which may be viewed with the 2132.Xr sysctl 8 2133variable 2134.Em vm.nkmempages . 2135See 2136.Pa /usr/include/machine/param.h 2137for the default upper and lower bounds. 2138The related options 2139.Sq NKMEMPAGES_MIN 2140and 2141.Sq NKMEMPAGES_MAX 2142allow the bounds to be overridden in the kernel configuration file. 2143These options are provided in the event the computed value is 2144insufficient resulting in an 2145.Dq out of space in kmem_map 2146panic. 2147.It Cd options SB_MAX=value 2148Sets the max size in bytes that a socket buffer is allowed to occupy. 2149The default is 256k, but sometimes it needs to be increased, for example 2150when using large TCP windows. 2151This option can be changed via 2152.Xr sysctl 8 2153as well. 2154.It Cd options SOMAXKVA=value 2155Sets the maximum size of kernel virtual memory that the socket buffers 2156are allowed to use. 2157The default is 16MB, but in situations where for example large TCP 2158windows are used this value must also be increased. 2159This option can be changed via 2160.Xr sysctl 8 2161as well. 2162.It Cd options BUFCACHE=value 2163Size of the buffer cache as a percentage of total available 2164.Tn RAM . 2165Ignored if BUFPAGES is also specified. 2166.It Cd options NBUF=value 2167Sets the number of buffer headers available, i.e., the number of 2168open files that may have a buffer cache entry. 2169Each buffer header 2170requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2171The default value is machine dependent, but is usually equal to the 2172value of BUFPAGES. 2173If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2174then NBUF may be reduced at run time so that the storage allocated 2175for buffer headers doesn't exceed that limit. 2176.It Cd options BUFPAGES=value 2177These options set the number of pages available for the buffer cache. 2178Their default value is a machine dependent value, often calculated as 2179between 5% and 10% of total available 2180.Tn RAM . 2181.It Cd options MAXTSIZ=bytes 2182Sets the maximum size limit of a process' text segment. 2183See 2184.Pa /usr/include/machine/vmparam.h 2185for the port-specific default. 2186.It Cd options DFLDSIZ=bytes 2187Sets the default size limit of a process' data segment, the value that 2188will be returned as the soft limit for 2189.Dv RLIMIT_DATA 2190(as returned by 2191.Xr getrlimit 2 ) . 2192See 2193.Pa /usr/include/machine/vmparam.h 2194for the port-specific default. 2195.It Cd options MAXDSIZ=bytes 2196Sets the maximum size limit of a process' data segment, the value that 2197will be returned as the hard limit for 2198.Dv RLIMIT_DATA 2199(as returned by 2200.Xr getrlimit 2 ) . 2201See 2202.Pa /usr/include/machine/vmparam.h 2203for the port-specific default. 2204.It Cd options DFLSSIZ=bytes 2205Sets the default size limit of a process' stack segment, the value that 2206will be returned as the soft limit for 2207.Dv RLIMIT_STACK 2208(as returned by 2209.Xr getrlimit 2 ) . 2210See 2211.Pa /usr/include/machine/vmparam.h 2212for the port-specific default. 2213.It Cd options MAXSSIZ=bytes 2214Sets the maximum size limit of a process' stack segment, the value that 2215will be returned as the hard limit for 2216.Dv RLIMIT_STACK 2217(as returned by 2218.Xr getrlimit 2 ) . 2219See 2220.Pa /usr/include/machine/vmparam.h 2221for the port-specific default. 2222.It Cd options DUMP_ON_PANIC=integer 2223Defaults to one. 2224If set to zero, the kernel will not dump to the dump device when 2225it panics, though dumps can still be forced via 2226.Xr ddb 4 2227with the 2228.Dq sync 2229command. 2230Note that this sets the value of the 2231.Em kern.dump_on_panic 2232.Xr sysctl 3 2233variable which may be changed at run time -- see 2234.Xr sysctl 8 2235for details. 2236.It Cd options USE_TOPDOWN_VM 2237User space memory allocations (as made by 2238.Xr mmap 2 ) 2239will be arranged in a 2240.Dq top down 2241fashion instead of the traditional 2242.Dq upwards from MAXDSIZ \&+ vm_daddr 2243method. 2244This includes the placement of 2245.Xr ld.so 1 . 2246Arranging memory in this manner allows either (or both of) the heap or 2247.Xr mmap 2 2248allocated space to grow larger than traditionally possible. 2249This option is not available on all ports, but is instead expected to be 2250offered on a port-by-port basis, after which some ports will commit to 2251using it by default. 2252See the files 2253.Pa /usr/include/uvm/uvm_param.h 2254for some implementation details, and 2255.Pa /usr/include/machine/vmparam.h 2256for port specific details including availability. 2257.It Cd options VMSWAP 2258Enable paging device/file support. 2259This option is on by default. 2260.It Cd options PDPOLICY_CLOCKPRO 2261Use CLOCK-Pro, an alternative page replace policy. 2262.El 2263.Ss Security Options 2264.Bl -ohang 2265.It Cd options INSECURE 2266Initializes the kernel security level with \-1 instead of 0. 2267This means that the system always starts in secure level \-1 mode, even when 2268running multiuser, unless the securelevel variable is set to value > \-1 in 2269.Pa /etc/rc.conf . 2270In this case the kernel security level will be raised to that value when the 2271.Pa /etc/rc.d/securelevel 2272script is run during system startup. 2273See the manual page for 2274.Xr init 8 2275for details on the implications of this. 2276The kernel secure level may manipulated by the superuser by altering the 2277.Em kern.securelevel 2278.Xr sysctl 3 2279variable (the secure level may only be lowered by a call from process ID 1, 2280i.e., 2281.Xr init 8 ) . 2282See also 2283.Xr secmodel_securelevel 9 , 2284.Xr sysctl 8 2285and 2286.Xr sysctl 3 . 2287.It Cd options VERIFIED_EXEC_FP_MD5 2288Enables support for MD5 hashes in Veriexec. 2289.It Cd options VERIFIED_EXEC_FP_SHA1 2290Enables support for SHA1 hashes in Veriexec. 2291.It Cd options VERIFIED_EXEC_FP_RMD160 2292Enables support for RMD160 hashes in Veriexec. 2293.It Cd options VERIFIED_EXEC_FP_SHA256 2294Enables support for SHA256 hashes in Veriexec. 2295.It Cd options VERIFIED_EXEC_FP_SHA384 2296Enables support for SHA384 hashes in Veriexec. 2297.It Cd options VERIFIED_EXEC_FP_SHA512 2298Enables support for SHA512 hashes in Veriexec. 2299.It Cd options PAX_MPROTECT=value 2300Enables PaX MPROTECT, 2301.Xr mprotect 2 2302restrictions from the PaX project. 2303.Pp 2304The 2305.Ar value 2306is the default value for the 2307.Em global 2308knob, see 2309.Xr sysctl 3 . 2310If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2311using 2312.Xr paxctl 8 . 2313If 1, PaX MPROTECT will be enabled for all programs. 2314Programs can be exempted using 2315.Xr paxctl 8 . 2316.Pp 2317See 2318.Xr security 7 2319for more details. 2320.It Cd options PAX_SEGVGUARD=value 2321Enables PaX Segvguard. 2322.Pp 2323The 2324.Ar value 2325is the default value for the 2326.Em global 2327knob, see 2328.Xr sysctl 3 . 2329If 0, PaX Segvguard will be enabled only if explicitly set on programs 2330using 2331.Xr paxctl 8 . 2332If 1, PaX Segvguard will be enabled to all programs, and exemption can 2333be done using 2334.Xr paxctl 8 . 2335.Pp 2336See 2337.Xr security 7 2338for more details. 2339.It Cd options PAX_ASLR=value 2340Enables PaX ASLR. 2341.Pp 2342The 2343.Ar value 2344is the default value for the 2345.Em global 2346knob, see 2347.Xr sysctl 3 . 2348If 0, PaX ASLR will be enabled only if explicitly set on programs 2349using 2350.Xr paxctl 8 . 2351If 1, PaX ASLR will be enabled to all programs, and exemption can 2352be done using 2353.Xr paxctl 8 . 2354.Pp 2355See 2356.Xr security 7 2357for more details. 2358.It Cd options USER_VA0_DISABLE_DEFAULT=value 2359Sets the initial value of the flag which controls whether user programs 2360can map virtual address 0. 2361The flag can be changed at runtime by 2362.Xr sysctl 3 . 2363.El 2364.Ss amiga-specific Options 2365.Bl -ohang 2366.It Cd options BB060STUPIDROM 2367When the bootloader (which passes 2368.Tn AmigaOS 2369.Tn ROM 2370information) claims we have a 68060 2371.Tn CPU 2372without 2373.Tn FPU , 2374go look into the Processor Configuration Register (PCR) to find out. 2375You need this with 2376.Tn Amiga 2377.Tn ROM Ns s 2378up to (at least) V40.xxx (OS3.1), 2379when you boot via the bootblocks and don't have a DraCo. 2380.It Cd options IOBZCLOCK=frequency 2381The IOBlix boards come with two different serial master clocks: older ones 2382use 24 MHz, newer ones use 22.1184 MHz. 2383The driver normally assumes the latter. 2384If your board uses 24 MHz, you can recompile your kernel with 2385options IOBZCLOCK=24000000 2386or patch the kernel variable 2387.Tn iobzclock 2388to the same value. 2389.It Cd options LIMITMEM=value 2390If there, limit the part of the first memory bank used by 2391.Nx 2392to value megabytes. 2393Default is unlimited. 2394.It Cd options P5PPC68KBOARD 2395Add special support for Phase5 mixed 68k+PPC boards. 2396Currently, this only affects rebooting from 2397.Nx 2398and is only needed on 68040+PPC, not on 239968060+PPC; without this, affected machines will hang after 2400.Nx 2401has shut 2402down and will only restart after a keyboard reset or a power cycle. 2403.El 2404.Ss atari-specific Options 2405.Bl -ohang 2406.It Cd options DISKLABEL_AHDI 2407Include support for AHDI (native Atari) disklabels. 2408.It Cd options DISKLABEL_NBDA 2409Include support for 2410.Nx Ns Tn /atari 2411labels. 2412If you don't set this option, it will be set automatically. 2413.Nx Ns Tn /atari 2414will not work without it. 2415.It Cd options FALCON_SCSI 2416Include support for the 5380-SCSI configuration as found on the Falcon. 2417.It Cd options RELOC_KERNEL 2418If set, the kernel will relocate itself to TT-RAM, if possible. 2419This will give you a slightly faster system. 2420.Em Beware 2421that on some TT030 systems, 2422the system will frequently dump with MMU-faults with this option enabled. 2423.It Cd options SERCONSOLE 2424Allow the modem1-port to act as the system-console. 2425A carrier should be active on modem1 during system boot to active 2426the console functionality. 2427.It Cd options TT_SCSI 2428Include support for the 5380-SCSI configuration as found on the TT030 2429and Hades. 2430.El 2431.Ss i386-specific Options 2432.Bl -ohang 2433.It Cd options CPURESET_DELAY=value 2434Specifies the time (in millisecond) to wait before doing a hardware reset 2435in the last phase of a reboot. 2436This gives the user a chance to see error messages from the shutdown 2437operations (like NFS unmounts, buffer cache flush, etc ...). 2438Setting this to 0 will disable the delay. 2439Default is 2 seconds. 2440.It Cd options VM86 2441Include support for virtual 8086 mode, used by 2442.Tn DOS 2443emulators and X servers to run BIOS code, e.g., for some VESA routines. 2444.It Cd options USER_LDT 2445Include i386-specific system calls for modifying the local descriptor table, 2446used by Windows emulators. 2447.It Cd options PAE 2448Enable 2449.Tn PAE (Physical Address Extension) 2450mode. 2451.Tn PAE 2452permits up to 36 bits physical addressing (64GB of physical memory), and 2453turns physical addresses to 64 bits entities in the memory management 2454subsystem. 2455Userland virtual address space remains at 32 bits (4GB). 2456.Tn PAE 2457mode is required to enable the 2458.Tn NX/XD (No-eXecute/eXecute Disable) 2459bit for pages, which allows marking certain ones as not being executable. 2460Any attempt to execute code from such a page will raise an exception. 2461.It Cd options REALBASEMEM=integer 2462Overrides the base memory size passed in from the boot block. 2463(Value given in kilobytes.) 2464Use this option only if the boot block reports the size incorrectly. 2465(Note that some 2466.Tn BIOS Ns es 2467put the extended 2468.Tn BIOS 2469data area at the top of base memory, and therefore report a smaller 2470base memory size to prevent programs overwriting it. 2471This is correct behavior, and you should not use the 2472.Em REALBASEMEM 2473option to access this memory). 2474.It Cd options REALEXTMEM=integer 2475Overrides the extended memory size passed in from the boot block. 2476(Value given in kilobytes. 2477Extended memory does not include the first megabyte.) 2478Use this option only if the boot block reports the size incorrectly. 2479.It Cd options CYRIX_CACHE_WORKS 2480Relevant only to the Cyrix 486DLC CPU. 2481This option is used to turn on the cache in hold-flush mode. 2482It is not turned on by default because it is known to have problems in 2483certain motherboard implementations. 2484.It Cd options CYRIX_CACHE_REALLY_WORKS 2485Relevant only to the Cyrix 486DLC CPU. 2486This option is used to turn on the cache in write-back mode. 2487It is not turned on by default because it is known to have problems in 2488certain motherboard implementations. 2489In order for this option to take effect, option 2490.Em CYRIX_CACHE_WORKS 2491must also be specified. 2492.It Cd options PCIBIOS 2493Enable support for initializing the 2494.Tn PCI 2495bus using information from the 2496.Tn BIOS . 2497See 2498.Xr pcibios 4 2499for details. 2500.It Cd options KSTACK_CHECK_DR0 2501Detect kernel stack overflow using DR0 register. 2502This option uses DR0 register exclusively so you can't use DR0 register for 2503other purpose (e.g., hardware breakpoint) if you turn this on. 2504.It Cd options MTRR 2505Include support for accessing MTRR registers from user-space. 2506See 2507.Xr i386_get_mtrr 2 . 2508.It Cd options BEEP_ONHALT 2509Make the system speaker emit several beeps when it is completely safe to 2510power down the computer after a 2511.Xr halt 8 2512command. 2513Requires 2514.Xr sysbeep 4 2515support. 2516.It Cd options BEEP_ONHALT_COUNT=times 2517Number of times to beep the speaker when 2518.Cd options BEEP_ONHALT 2519is enabled. 2520Defaults to 3. 2521.It Cd options BEEP_ONHALT_PITCH=hz 2522The tone frequency used when 2523.Cd options BEEP_ONHALT 2524option, in hertz. 2525Defaults to 1500. 2526.It Cd options BEEP_ONHALT_PERIOD=msecs 2527The duration of each beep when 2528.Cd options BEEP_ONHALT 2529is enabled, in milliseconds. 2530Defaults to 250. 2531.It Cd options MULTIBOOT 2532Makes the kernel Multiboot-compliant, allowing it to be booted through 2533a Multiboot-compliant boot manager such as GRUB. 2534See 2535.Xr multiboot 8 2536for more information. 2537.It Cd options SPLASHSCREEN 2538Display a splash screen during boot. 2539.It Cd options SPLASHSCREEN_PROGRESS 2540Display a progress bar at the splash screen during boot. 2541This option requires 2542.Em SPLASHSCREEN . 2543.El 2544.Ss isa-specific Options 2545Options specific to 2546.Xr isa 4 2547busses. 2548.Bl -ohang 2549.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2550Control the section of IO bus space used for PCMCIA bus space mapping. 2551Ideally the probed defaults are satisfactory, however in practice 2552that is not always the case. 2553See 2554.Xr pcmcia 4 2555for details. 2556.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2557Controls the allowable interrupts that may be used for 2558.Tn PCMCIA 2559devices. 2560This mask is a logical-or of power-of-2s of allowable interrupts: 2561.Bd -literal -offset 04n 2562.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2563 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2564 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2565 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2566 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2567.Ed 2568.It Cd options PCKBC_CNATTACH_SELFTEST 2569Perform a self test of the keyboard controller before attaching it as a 2570console. 2571This might be necessary on machines where we boot on cold iron, and 2572pckbc refuses to talk until we request a self test. 2573Currently only the netwinder port uses it. 2574.It Cd options PCKBD_CNATTACH_MAY_FAIL 2575If this option is set the PS/2 keyboard will not be used as the console 2576if it cannot be found during boot. 2577This allows other keyboards, like USB, to be the console keyboard. 2578.It Cd options PCKBD_LAYOUT=layout 2579Sets the default keyboard layout, see 2580.Xr pckbd 4 . 2581.El 2582.Ss m68k-specific Options 2583.Bl -ohang 2584.It Cd options FPU_EMULATE 2585Include support for MC68881/MC68882 emulator. 2586.It Cd options FPSP 2587Include support for 68040 floating point. 2588.It Cd options M68020,M68030,M68040,M68060 2589Include support for a specific 2590.Tn CPU , 2591at least one (the one you are using) should be specified. 2592.It Cd options M060SP 2593Include software support for 68060. 2594This provides emulation of unimplemented 2595integer instructions as well as emulation of unimplemented floating point 2596instructions and data types and software support for floating point traps. 2597.El 2598.Ss powerpc-specific Options (OEA Only) 2599.Bl -ohang 2600.It Cd options PMAP_MEMLIMIT=value 2601Limit the amount of memory seen by the kernel to 2602.Ar value 2603bytes. 2604.It Cd options PTEGCOUNT=value 2605Specify the size of the page table as 2606.Ar value 2607PTE groups. 2608Normally, one PTEG is allocated per physical page frame. 2609.El 2610.Ss sparc-specific Options 2611.Bl -ohang 2612.It Cd options AUDIO_DEBUG 2613Enable simple event debugging of the logging of the 2614.Xr audio 4 2615device. 2616.It Cd options BLINK 2617Enable blinking of LED. 2618Blink rate is full cycle every N seconds for 2619N \*[Lt] then current load average. 2620See 2621.Xr getloadavg 3 . 2622.\" .It Cd options COLORFONT_CACHE 2623.\" What does this do? 2624.It Cd options COUNT_SW_LEFTOVERS 2625Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2626sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2627variables accessible from 2628.Xr ddb 4 . 2629See 2630.Xr sw 4 . 2631.It Cd options DEBUG_ALIGN 2632Adds debugging messages calls when user-requested alignment fault 2633handling happens. 2634.It Cd options DEBUG_EMUL 2635Adds debugging messages calls for emulated floating point and 2636alignment fixing operations. 2637.It Cd options DEBUG_SVR4 2638Prints registers messages calls for emulated SVR4 getcontext and 2639setcontext operations. 2640See 2641.Em options COMPAT_SVR4 . 2642.It Cd options EXTREME_DEBUG 2643Adds debugging functions callable from 2644.Xr ddb 4 . 2645The debug_pagetables, test_region and print_fe_map 2646functions print information about page tables for the SUN4M 2647platforms only. 2648.It Cd options EXTREME_EXTREME_DEBUG 2649Adds extra info to 2650.Em options EXTREME_DEBUG . 2651.It Cd options FPU_CONTEXT 2652Make 2653.Em options COMPAT_SVR4 2654getcontext and setcontext include floating point registers. 2655.It Cd options MAGMA_DEBUG 2656Adds debugging messages to the 2657.Xr magma 4 2658device. 2659.It Cd options RASTERCONS_FULLSCREEN 2660Use the entire screen for the console. 2661.It Cd options RASTERCONS_SMALLFONT 2662Use the Fixed font on the console, instead of the normal font. 2663.It Cd options SUN4 2664Support sun4 class machines. 2665.It Cd options SUN4C 2666Support sun4c class machines. 2667.It Cd options SUN4M 2668Support sun4m class machines. 2669.It Cd options SUN4_MMU3L 2670.\" XXX ??? 2671Enable support for sun4 3-level MMU machines. 2672.It Cd options V9 2673Enable SPARC V9 assembler in 2674.Xr ddb 4 . 2675.El 2676.Ss sparc64-specific Options 2677.Bl -ohang 2678.It Cd options AUDIO_DEBUG 2679Enable simple event debugging of the logging of the 2680.Xr audio 4 2681device. 2682.It Cd options BLINK 2683Enable blinking of LED. 2684Blink rate is full cycle every N seconds for 2685N \*[Lt] then current load average. 2686See 2687.Xr getloadavg 3 . 2688.El 2689.Ss x68k-specific Options 2690.Bl -ohang 2691.It Cd options EXTENDED_MEMORY 2692Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2693.It Cd options JUPITER 2694Include support for Jupiter-X MPU accelerator 2695.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2696Use the built-in serial port as the system-console. 2697Speed is specified in bps, defaults to 9600. 2698.It Cd options ITE_KERNEL_ATTR=value 2699Set the kernel message attribute for ITE. 2700Value, an integer, is a logical or of the following values: 2701.Bl -tag -width 4n -compact -offset indent 2702.It 1 2703color inversed 2704.It 2 2705underlined 2706.It 4 2707bolded 2708.El 2709.El 2710.\" The following requests should be uncommented and used where appropriate. 2711.\" .Sh FILES 2712.\" .Sh EXAMPLES 2713.Sh SEE ALSO 2714.Xr config 1 , 2715.Xr gdb 1 , 2716.Xr ktrace 1 , 2717.Xr pmc 1 , 2718.Xr quota 1 , 2719.Xr vndcompress 1 , 2720.Xr gettimeofday 2 , 2721.Xr i386_get_mtrr 2 , 2722.Xr i386_iopl 2 , 2723.Xr msgctl 2 , 2724.Xr msgget 2 , 2725.Xr msgrcv 2 , 2726.Xr msgsnd 2 , 2727.Xr ntp_adjtime 2 , 2728.Xr ntp_gettime 2 , 2729.Xr reboot 2 , 2730.Xr semctl 2 , 2731.Xr semget 2 , 2732.Xr semop 2 , 2733.Xr shmat 2 , 2734.Xr shmctl 2 , 2735.Xr shmdt 2 , 2736.Xr shmget 2 , 2737.Xr sysctl 3 , 2738.Xr apm 4 , 2739.Xr ddb 4 , 2740.Xr inet 4 , 2741.Xr iso 4 , 2742.Xr md 4 , 2743.Xr pcibios 4 , 2744.Xr pcmcia 4 , 2745.Xr ppp 4 , 2746.Xr userconf 4 , 2747.Xr vnd 4 , 2748.Xr wscons 4 , 2749.Xr config 5 , 2750.Xr edquota 8 , 2751.Xr init 8 , 2752.Xr mdsetimage 8 , 2753.Xr mount_cd9660 8 , 2754.Xr mount_fdesc 8 , 2755.Xr mount_kernfs 8 , 2756.Xr mount_lfs 8 , 2757.Xr mount_mfs 8 , 2758.Xr mount_msdos 8 , 2759.Xr mount_nfs 8 , 2760.Xr mount_ntfs 8 , 2761.Xr mount_null 8 , 2762.Xr mount_portal 8 , 2763.Xr mount_procfs 8 , 2764.Xr mount_udf 8 , 2765.Xr mount_umap 8 , 2766.Xr mount_union 8 , 2767.Xr mrouted 8 , 2768.Xr newfs_lfs 8 , 2769.Xr ntpd 8 , 2770.Xr quotaon 8 , 2771.Xr rpc.rquotad 8 , 2772.Xr sysctl 8 , 2773.Xr in_getifa 9 2774.Sh HISTORY 2775The 2776.Nm 2777man page first appeared in 2778.Nx 1.3 . 2779.Sh BUGS 2780The 2781.Em EON 2782option should be a pseudo-device, and is also very fragile. 2783