1.\" $NetBSD: options.4,v 1.415 2012/03/22 20:34:38 drochner 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 21, 2012 34.Dt OPTIONS 4 35.Os 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Qq Ar filename 66Conditionally includes another kernel configuration file whose name is 67.Ar filename , 68which may be double-quoted and may be an explicit path or relative to 69the kernel source directory. 70Failure to open the named file is ignored. 71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ 72Oo dumps on Ar dumpdev Oc 73Defines a configuration whose kernel executable is named 74.Ar exec_name , 75normally 76.Dq netbsd , 77with its root file system of type 78.Ar fstype 79on the device 80.Ar rootdev , 81and optionally specifying the location of kernel core dumps on the device 82.Ar dumpdev . 83.Ar dev 84or 85.Ar dumpdev 86and 87.Ar fstype 88may be specified as 89.Dq \&? , 90which is a wild card. 91The root 92.Ar fstype 93and 94.Ar dumpdev 95are optional and assumed to be wild carded if they are not specified. 96.It Ar device_instance No at Ar attachment \ 97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc 98Define an instance of the device driver 99.Ar device_instance 100that attaches to the bus or device named 101.Ar attachment . 102An 103.Ar attachment 104may require additional information on where the device can be found, such 105as an address, channel, function, offset, and/or slot, referred to as 106.Ar locators , 107whose 108.Ar value 109often may be a wild card, 110.Dq \&? . 111Some device drivers have one or more 112.Ar flags 113that can be adjusted to affect the way they operate. 114.It Sy file-system Ar fs_name Op , Ar fs_name Op ... 115Include support for the file-system 116.Ar fs_name . 117.It Sy ident Qq Ar string 118Sets the kernel identification string to 119.Ar string . 120.It Sy include Qq Ar filename 121Functions the same as 122.Ar cinclude , 123except failure to open 124.Ar filename 125produces a fatal error. 126.It Sy options Ar option_name Op , Ar option_name=value Op ... 127Specifies (or sets) the option, or comma-separated list of options, 128.Ar option_name . 129Some options expect to be assigned a value, which may be an integer, 130a double-quoted word, a bare word, or an empty string 131.Pq Qq . 132Note that those are eventually handled by the C compiler, so the rules 133of that language apply. 134.Pp 135.Em Note : 136Options that are not defined by device definition files are passed to 137the compile process as 138.Fl D 139flags to the C compiler. 140.It Sy makeoptions Ar name=value 141Defines a 142.Xr make 1 143macro 144.Ar name 145with the value 146.Ar value 147in the kernel Makefile. 148.It Sy maxusers Ar integer 149Set the maxusers variable in the kernel. 150.It Sy no Ar keyword Ar name Op Ar arguments Op ... 151For the 152.Xr config 1 153.Ar keywords 154file-system, makeoptions, options, and pseudo-device, 155.Ar no 156removes the file-system, makeoption, options, or pseudo-device, 157.Ar name . 158This is useful when a kernel configuration file includes another which 159has undesired options. 160.Pp 161For example, a local configuration file that wanted the kitchen sink, but 162not COMPAT_09 or bridging, might be: 163.Bd -literal -offset indent 164include "arch/i386/conf/GENERIC" 165no options COMPAT_09 166no pseudo-device bridge 167.Ed 168.It Sy pseudo-device Ar name Op Ar N 169Includes support for the pseudo-device 170.Ar name . 171Some pseudo-devices can have multiple or 172.Ar N 173instances. 174.El 175.Ss Compatibility Options 176.Bl -ohang 177.It Cd options COMPAT_09 178Enable binary compatibility with 179.Nx 0.9 . 180This enables support for 18116-bit user, group, and process IDs (following revisions support 18232-bit identifiers). 183It also allows the use of the deprecated 184.Xr getdomainname 3 , 185.Xr setdomainname 3 , 186and 187.Xr uname 3 188syscalls. 189This option also allows using numeric file system identifiers rather 190than strings. 191Post 192.Nx 0.9 193versions use string identifiers. 194.It Cd options COMPAT_10 195Enable binary compatibility with 196.Nx 1.0 . 197This option allows the use of the file system name of 198.Dq ufs 199as an alias for 200.Dq ffs . 201The name 202.Dq ffs 203should be used post 1.0 in 204.Pa /etc/fstab 205and other files. 206It also adds old syscalls for the 207.At V 208shared memory interface. 209This was changed post 1.0 to work on 64-bit architectures. 210This option also enables 211.Dq sgtty 212compatibility, without which programs using the old interface produce 213an 214.Dq inappropriate ioctl 215error, and 216.Pa /dev/io 217only works when this option is set in the kernel, 218see 219.Xr io 4 220on ports that support it. 221.It Cd options COMPAT_11 222Enable binary compatibility with 223.Nx 1.1 . 224This allows binaries running on the i386 port to gain direct access to 225the io ports by opening 226.Pa /dev/io 227read/write. 228This functionality was replaced by 229.Xr i386_iopl 2 230post 1.1. 231On the 232.Tn Atari 233port, the location of the disk label was moved after 1.1. 234When the 235.Em COMPAT_11 236option is set, the kernel will read (pre) 1.1 style disk labels as a 237last resort. 238When a disk label is re-written, the old style label will be replaced 239with a post 1.1 style label. 240This also enables the 241.Em EXEC_ELF_NOTELESS 242option. 243.It Cd options COMPAT_12 244Enable binary compatibility with 245.Nx 1.2 . 246This allows the use of old syscalls for 247.Fn reboot 248and 249.Fn swapon . 250The syscall numbers were changed post 1.2 to add functionality to the 251.Xr reboot 2 252syscall, and the new 253.Xr swapctl 2 254interface was introduced. 255This also enables the 256.Em EXEC_ELF_NOTELESS 257option. 258.It Cd options COMPAT_13 259Enable binary compatibility with 260.Nx 1.3 . 261This allows the use of old syscalls for 262.Fn sigaltstack , 263and also enables the old 264.Xr swapctl 2 265command 266.Dv SWAP_STATS 267(now called 268.Dv SWAP_OSTATS ) , 269which does not include the 270.Fa se_path 271member of 272.Va struct swapent . 273.It Cd options COMPAT_14 274Enable binary compatibility with 275.Nx 1.4 . 276This allows some old 277.Xr ioctl 2 278on 279.Xr wscons 4 280to be performed, and allows the 281.Dv NFSSVC_BIOD 282mode of the 283.Xr nfssvc 2 284system call to be used for compatibility with the deprecated nfsiod program. 285.It Cd options COMPAT_15 286Enable binary compatibility with 287.Nx 1.5 . 288Since there were no API changes from 289.Nx 1.5 290and 291.Nx 1.6 , 292this option does nothing. 293.It Cd options COMPAT_16 294Enable binary compatibility with 295.Nx 1.6 . 296This allows the use of old signal trampoline code which has been deprecated 297with the addition of 298.Xr siginfo 2 . 299.It Cd options COMPAT_20 300Enable binary compatibility with 301.Nx 2.0 . 302This allows the use of old syscalls for 303.Fn statfs , 304.Fn fstatfs , 305.Fn getfsstat 306and 307.Fn fhstatfs , 308which have been deprecated with the addition of the 309.Xr statvfs 2 , 310.Xr fstatvfs 2 , 311.Xr getvfsstat 2 312and 313.Xr fhstatvfs 2 314system calls. 315.It Cd options COMPAT_30 316Enable binary compatibility with 317.Nx 3.0 . 318See 319.Xr compat_30 8 320for details about the changes made after the 321.Nx 3.0 322release. 323.It Cd options COMPAT_43 324Enables compatibility with 325.Bx 4.3 . 326This adds an old syscall for 327.Xr lseek 2 . 328It also adds the ioctls for 329.Dv TIOCGETP 330and 331.Dv TIOCSETP . 332The return values for 333.Xr getpid 2 , 334.Xr getgid 2 , 335and 336.Xr getuid 2 337syscalls are modified as well, to return the parent's PID and 338UID as well as the current process's. 339It also enables the deprecated 340.Dv NTTYDISC 341terminal line discipline. 342It also provides backwards compatibility with 343.Dq old 344SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 345binary compatibility with code written before the introduction of the 346sa_len field in sockaddrs. 347It also enables 348support for some older pre 349.Bx 4.4 350socket calls. 351.It Cd options COMPAT_BSDPTY 352This option is currently on by default and enables the pty multiplexer 353.Xr ptm 4 354and 355.Xr ptmx 4 356to find and use ptys named 357.Pa /dev/ptyXX 358(master) and 359.Pa /dev/ttyXX 360(slave). 361Eventually this option will become optional as ptyfs based pseudo-ttys become 362the default, see 363.Xr mount_ptyfs 8 . 364.It Cd options COMPAT_SVR4 365On those architectures that support it, this enables binary 366compatibility with 367.At V.4 368applications built for the same architecture. 369This currently includes the i386, m68k, and sparc ports. 370.It Cd options COMPAT_LINUX 371On those architectures that support it, this enables binary 372compatibility with Linux ELF and 373.Xr a.out 5 374applications built for the same architecture. 375This currently includes the alpha, arm, i386, m68k, mips, powerpc and 376x86_64 ports. 377.It Cd options COMPAT_LINUX32 378On those 64 bit architectures that support it, this enables binary 379compatibility with 32 bit Linux binaries. 380For now this is limited to running i386 ELF Linux binaries on amd64. 381.It Cd options COMPAT_SUNOS 382On those architectures that support it, this enables binary 383compatibility with 384.Tn SunOS 4.1 385applications built for the same architecture. 386This currently includes the sparc, sparc64 and most or all m68k ports. 387Note that the sparc64 requires the 388.Em COMPAT_NETBSD32 389option for 64-bit kernels, in addition to this option. 390.It Cd options COMPAT_ULTRIX 391On those architectures that support it, this enables binary 392compatibility with 393.Tn ULTRIX 394applications built for the same architecture. 395This currently is limited to the pmax. 396The functionality of this option is unknown. 397.It Cd options COMPAT_FREEBSD 398On those architectures that support it, this enables binary 399compatibility with 400.Fx 401applications built for the same architecture. 402At the moment this is limited to the i386 port. 403.It Cd options COMPAT_IBCS2 404On those architectures that support it, this enables binary 405compatibility with iBCS2 or SVR3 applications built for the same architecture. 406This is currently limited to the i386 and vax ports. 407.It Cd options COMPAT_OSF1 408On those architectures that support it, this enables binary 409compatibility with 410.Tn Digital 411.Ux 412.Po 413formerly 414.Tn OSF/1 415.Pc 416applications built for the same architecture. 417This is currently limited to the alpha port. 418.It Cd options COMPAT_NOMID 419Enable compatibility with 420.Xr a.out 5 421executables that lack a machine ID. 422This includes 423.Nx 0.8 Ns 's 424ZMAGIC format, and 386BSD and BSDI's 425QMAGIC, NMAGIC, and OMAGIC 426.Xr a.out 5 427formats. 428.It Cd options COMPAT_NETBSD32 429On those architectures that support it, this enables binary 430compatibility with 32-bit applications built for the same architecture. 431This is currently limited to the amd64 and sparc64 ports, and only 432applicable for 64-bit kernels. 433.It Cd options COMPAT_SVR4_32 434On those architectures that support it, this enables binary 435compatibility with 32-bit SVR4 applications built for the same architecture. 436This is currently limited to the sparc64 port, and only applicable for 43764-bit kernels. 438.It Cd options COMPAT_AOUT_M68K 439On m68k architectures which have switched to ELF, 440this enables binary compatibility with 441.Nx Ns Tn /m68k 442.Xr a.out 5 443executables on 444.Nx Ns Tn /m68k 445ELF kernels. 446This handles alignment incompatibility of m68k ABI between 447a.out and ELF which causes the structure padding differences. 448Currently only some system calls which use 449.Va struct stat 450are adjusted and some binaries which use 451.Xr sysctl 3 452to retrieve network details would not work properly. 453.It Cd options EXEC_ELF_NOTELESS 454Run unidentified ELF binaries as 455.Nx 456binaries. 457This might be needed for very old 458.Nx 459ELF binaries on some archs. 460These old binaries didn't contain an appropriate 461.Li .note.netbsd.ident 462section, and thus can't be identified by the kernel as 463.Nx 464binaries otherwise. 465Beware - if this option is on, the kernel would run 466.Em any 467unknown ELF binaries as if they were 468.Nx 469binaries. 470.It Cd options P1003_1B_SEMAPHORE 471Includes kernel support for the standard C library 472.Pq libc 473functions that implement semaphores as specified in 474.St -p1003.1-96 . 475.El 476.Ss Debugging Options 477.Bl -ohang 478.It Cd options DDB 479Compiles in a kernel debugger for diagnosing kernel problems. 480See 481.Xr ddb 4 482for details. 483.Em NOTE : 484not available on all architectures. 485.It Cd options DDB_FROMCONSOLE=integer 486If set to non-zero, DDB may be entered by sending a break on a serial 487console or by a special key sequence on a graphics console. 488A value of "0" ignores console breaks or key sequences. 489If not explicitly specified, the default value is "1". 490Note that this sets the value of the 491.Em ddb.fromconsole 492.Xr sysctl 3 493variable which may be changed at run time -- see 494.Xr sysctl 8 495for details. 496.It Cd options DDB_HISTORY_SIZE=integer 497If this is non-zero, enable history editing in the kernel debugger 498and set the size of the history to this value. 499.It Cd options DDB_ONPANIC 500The default if not specified is 501.Dq 1 502- just enter into DDB. 503If set to 504.Dq 2 505the kernel will 506attempt to print out a stack trace before entering into DDB. 507If set to 508.Dq 0 509the kernel will attempt to print out a stack trace 510and reboot the system. 511If set to 512.Dq -1 513then neither a stack trace is printed or DDB entered - 514it is as if DDB were not compiled into the kernel. 515Note that this sets the value of the 516.Em ddb.onpanic 517.Xr sysctl 3 518variable which may be changed at run time -- see 519.Xr sysctl 8 520for details. 521.It Cd options DDB_COMMANDONENTER=string 522This option specify commands which will be executed on each entry to DDB. 523This sets the default value of the 524.Em ddb.commandonenter 525.Xr sysctl 3 526variable which may be changed at run time. 527.It Cd options DDB_BREAK_CHAR=integer 528This option overrides using break to enter the kernel debugger 529on the serial console. 530The value given is the ASCII value to be used instead. 531This is currently only supported by the com driver. 532.It Cd options DDB_VERBOSE_HELP 533This option adds more verbose descriptions to the 534.Em help 535command. 536.It Cd options KGDB 537Compiles in a remote kernel debugger stub for diagnosing kernel problems 538using the 539.Dq remote target 540feature of gdb. 541See 542.Xr gdb 1 543for details. 544.Em NOTE : 545not available on all architectures. 546.It Cd options KGDB_DEV 547Device number 548.Po 549as a 550.Dv dev_t 551.Pc 552of kgdb device. 553.It Cd options KGDB_DEVADDR 554Memory address of kgdb device. 555.It Cd options KGDB_DEVMODE 556Permissions of kgdb device. 557.It Cd options KGDB_DEVNAME 558Device name of kgdb device. 559.It Cd options KGDB_DEVRATE 560Baud rate of kgdb device. 561.It Cd makeoptions DEBUG="-g" 562The 563.Fl g 564flag causes 565.Pa netbsd.gdb 566to be built in addition to 567.Pa netbsd . 568.Pa netbsd.gdb 569is useful for debugging kernel crash dumps with gdb. 570See 571.Xr gdb 1 572for details. 573This also turns on 574.Em options DEBUG 575(which see). 576.It Cd options DEBUG 577Turns on miscellaneous kernel debugging. 578Since options are turned into preprocessor defines (see above), 579.Em options DEBUG 580is equivalent to doing a 581.Em #define DEBUG 582throughout the kernel. 583Much of the kernel has 584.Em #ifdef DEBUG 585conditionalized debugging code. 586Note that many parts of the kernel (typically device drivers) include their own 587.Em #ifdef XXX_DEBUG 588conditionals instead. 589This option also turns on certain other options, 590which may decrease system performance. 591.It Cd options DIAGNOSTIC 592Adds code to the kernel that does internal consistency checks. 593This code will cause the kernel to panic if corruption of internal data 594structures is detected. 595These checks can decrease performance up to 15%. 596.It Cd options LOCKDEBUG 597Adds code to the kernel to detect incorrect use of locking primitives 598(mutex, rwlock, simplelock). 599This code will cause the kernel to check for dead lock conditions. 600It will also check for memory being freed to not contain initialised 601lock primitives. 602Functions for use in 603.Xr ddb 4 604to check lock chains etc. are also enabled. 605These checks are very expensive and can decrease performance on 606multi-processor machines by a factor of three. 607.It Cd options KSTACK_CHECK_MAGIC 608Check kernel stack usage and panic if stack overflow is detected. 609This check is performance sensitive because it scans stack on each context 610switch. 611.It Cd options KTRACE 612Add hooks for the system call tracing facility, which allows users to 613watch the system call invocation behavior of processes. 614See 615.Xr ktrace 1 616for details. 617.It Cd options MSGBUFSIZE=integer 618This option sets the size of the kernel message buffer. 619This buffer holds the kernel output of 620.Fn printf 621when not (yet) read by 622.Xr syslogd 8 . 623This is particularly useful when the system has crashed and you wish to lookup 624the kernel output from just before the crash. 625Also, since the autoconfig output becomes more and more verbose, 626it sometimes happens that the message buffer overflows before 627.Xr syslogd 8 628was able to read it. 629Note that not all systems are capable of obtaining a variable sized message 630buffer. 631There are also some systems on which memory contents are not preserved 632across reboots. 633.It Cd options MALLOCLOG 634Enables an event log for 635.Xr malloc 9 . 636Useful for tracking down 637.Dq Data modified on freelist 638and 639.Dq multiple free 640problems. 641.It Cd options MALLOCLOGSIZE=integer 642Defines the number of entries in the malloc log. 643Default is 100000 entries. 644.It Cd options UVMHIST 645Enables the UVM history logs, which create in-memory traces of 646various UVM activities. 647These logs can be displayed be calling 648.Fn uvmhist_dump 649or 650.Fn uvm_hist 651with appropriate arguments from DDB. 652See the kernel source file sys/uvm/uvm_stat.c for details. 653.It Cd options UVMHIST_PRINT 654Prints the UVM history logs on the system console as entries are added. 655Note that the output is 656.Em extremely 657voluminous, so this option is really only useful for debugging 658the very earliest parts of kernel initialization. 659.El 660.Ss File Systems 661.Bl -ohang 662.It Cd file-system FFS 663Includes code implementing the Berkeley Fast File System 664.Po Em FFS Pc . 665Most machines need this if they are not running diskless. 666.It Cd file-system EXT2FS 667Includes code implementing the Second Extended File System 668.Po Em ext2 Pc , 669revision 0 and revision 1 with the 670.Em filetype , 671.Em sparse_super 672and 673.Em large_file 674options. 675This is the most commonly used file system on the Linux operating system, 676and is provided here for compatibility. 677Some of the specific features of 678.Em ext2 679like the "behavior on errors" are not implemented. 680See 681.Xr mount_ext2fs 8 682for details. 683.It Cd file-system LFS 684.Bq Em EXPERIMENTAL 685Include the Log-structured File System 686.Po Em LFS Pc . 687See 688.Xr mount_lfs 8 689and 690.Xr newfs_lfs 8 691for details. 692.It Cd file-system MFS 693Include the Memory File System 694.Po Em MFS Pc . 695This file system stores files in swappable memory, and produces 696notable performance improvements when it is used as the file store 697for 698.Pa /tmp 699and similar file systems. 700See 701.Xr mount_mfs 8 702for details. 703.It Cd file-system NFS 704Include the client side of the Network File System 705.Pq Tn NFS 706remote file sharing protocol. 707Although the bulk of the code implementing 708.Tn NFS 709is kernel based, several user level daemons are needed for it to work. 710See 711.Xr mount_nfs 8 712for details. 713.It Cd file-system CD9660 714Includes code for the 715.Tn ISO 7169660 + Rock Ridge file system, which is the standard file system on many 717.Tn CD-ROM 718discs. 719Useful primarily if you have a 720.Tn CD-ROM 721drive. 722See 723.Xr mount_cd9660 8 724for details. 725.It Cd file-system MSDOSFS 726Includes the 727.Tn MS-DOS 728FAT file system, which is reportedly still used 729by unfortunate people who have not heard about 730.Nx . 731Also implements the 732.Tn Windows 95 733extensions to the same, which permit the use of longer, mixed case 734file names. 735See 736.Xr mount_msdos 8 737and 738.Xr fsck_msdos 8 739for details. 740.It Cd file-system NTFS 741.Bq Em EXPERIMENTAL 742Includes code for the 743.Tn Microsoft Windows NT 744file system. 745See 746.Xr mount_ntfs 8 747for details. 748.It Cd file-system FDESC 749Includes code for a file system, conventionally mounted on 750.Pa /dev/fd , 751which permits access to the per-process file descriptor space via 752special files in the file system. 753See 754.Xr mount_fdesc 8 755for details. 756Note that this facility is redundant, and thus unneeded on most 757.Nx 758systems, since the 759.Xr fd 4 760pseudo-device driver already provides identical functionality. 761On most 762.Nx 763systems, instances of 764.Xr fd 4 765are mknoded under 766.Pa /dev/fd/ 767and on 768.Pa /dev/stdin , 769.Pa /dev/stdout , 770and 771.Pa /dev/stderr . 772.It Cd file-system KERNFS 773Includes code which permits the mounting of a special file system 774(normally mounted on 775.Pa /kern ) 776in which files representing various kernel variables and parameters 777may be found. 778See 779.Xr mount_kernfs 8 780for details. 781.It Cd file-system NULLFS 782Includes code for a loopback file system. 783This permits portions of the file hierarchy to be re-mounted in other places. 784The code really exists to provide an example of a stackable file system layer. 785See 786.Xr mount_null 8 787for details. 788.It Cd file-system OVERLAY 789Includes code for a file system filter. 790This permits the overlay file system to intercept all access to an underlying 791file system. 792This file system is intended to serve as an example of a stacking file 793system which has a need to interpose itself between an underlying file 794system and all other access. 795See 796.Xr mount_overlay 8 797for details. 798.It Cd file-system PROCFS 799Includes code for a special file system (conventionally mounted on 800.Pa /proc ) 801in which the process space becomes visible in the file system. 802Among 803other things, the memory spaces of processes running on the system are 804visible as files, and signals may be sent to processes by writing to 805.Pa ctl 806files in the procfs namespace. 807See 808.Xr mount_procfs 8 809for details. 810.It Cd file-system UDF 811.Bq Em EXPERIMENTAL 812Includes code for the UDF file system commonly found on CD and DVD 813media but also on USB sticks. 814Currently supports read and write access upto UDF 2.01 and somewhat limited 815write support for UDF 2.50. 816It is marked experimental since there is no 817.Xr fsck_udf 8 . 818See 819.Xr mount_udf 8 820for details. 821.It Cd file-system UMAPFS 822Includes a loopback file system in which user and group IDs may be 823remapped -- this can be useful when mounting alien file systems with 824different UIDs and GIDs than the local system. 825See 826.Xr mount_umap 8 827for details. 828.It Cd file-system UNION 829.Bq Em EXPERIMENTAL 830Includes code for the union file system, which permits directories to 831be mounted on top of each other in such a way that both file systems 832remain visible -- this permits tricks like allowing writing (and the 833deleting of files) on a read-only file system like a 834.Tn CD-ROM 835by mounting a local writable file system on top of the read-only file system. 836See 837.Xr mount_union 8 838for details. 839.It Cd file-system CODA 840.Bq Em EXPERIMENTAL 841Includes code for the Coda file system. 842Coda is a distributed file system like NFS and AFS. 843It is freely available, like NFS, but it functions much like AFS in being a 844.Dq stateful 845file system. 846Both Coda and AFS cache files on your local machine to improve performance. 847Then Coda goes a step further than AFS by letting you access the cached 848files when there is no available network, viz. disconnected laptops and 849network outages. 850In Coda, both the client and server are outside the kernel which makes 851them easier to experiment with. 852Coda is available for several UNIX and non-UNIX platforms. 853See 854.Lk http://www.coda.cs.cmu.edu 855for more details. 856.Em NOTE : 857You also need to enable the pseudo-device, vcoda, for the Coda 858file system to work. 859.It Cd file-system SMBFS 860.Bq Em EXPERIMENTAL 861Includes code for the SMB/CIFS file system. 862See 863.Xr mount_smbfs 8 864for details. 865.Em NOTE : 866You also need to enable the pseudo-device, nsmb, for the SMB 867file system to work. 868.It Cd file-system PTYFS 869.Bq Em EXPERIMENTAL 870Includes code for a special file system (normally mounted on 871.Pa /dev/pts ) 872in which pseudo-terminal slave devices become visible in the file system. 873See 874.Xr mount_ptyfs 8 875for details. 876.It Cd file-system TMPFS 877Includes code for the efficient memory file system, normally used over 878.Pa /tmp . 879See 880.Xr mount_tmpfs 8 881for details. 882.It Cd file-system PUFFS 883Includes kernel support for the pass-to-userspace framework file system. 884It can be used to implement file system functionality in userspace. 885See 886.Xr puffs 3 887for more details. 888This enables for example sshfs: 889.Xr mount_psshfs 8 . 890.El 891.Ss File System Options 892.Bl -ohang 893.It Cd options MAGICLINKS 894Enables the expansion of special strings 895.Po 896beginning with 897.Dq @ 898.Pc 899when traversing symbolic links. 900See 901.Xr symlink 7 902for a list of supported strings. 903Note that this option only controls the enabling of this feature 904by the kernel at boot-up. 905This feature can still be manipulated with the 906.Xr sysctl 8 907command regardless of the setting of this option. 908.It Cd options NFSSERVER 909Include the server side of the 910.Em NFS 911(Network File System) remote file sharing protocol. 912Although the bulk of the code implementing 913.Em NFS 914is kernel based, several user level daemons are needed for it to 915work. 916See 917.Xr mountd 8 918and 919.Xr nfsd 8 920for details. 921.It Cd options QUOTA 922Enables kernel support for file system quotas. 923See 924.Xr quotaon 8 , 925.Xr edquota 8 , 926and 927.Xr quota 1 928for details. 929Note that quotas only work on 930.Dq ffs 931file systems, although 932.Xr rpc.rquotad 8 933permits them to be accessed over 934.Em NFS . 935.It Cd options QUOTA2 936Enables kernel support for the new file system quotas format. 937See 938.Xr tunefs 8 , 939.Xr newfs 8 , 940.Xr mount_mfs 8 , 941.Xr edquota 8 , 942and 943.Xr quota 1 944for details. 945Note that quota2 is only supported by 946.Dq ffs 947and 948.Dq mfs 949file systems at this time. 950.It Cd options FFS_EI 951Enable ``Endian-Independent'' FFS support. 952This allows a system to mount an FFS file system created for another 953architecture, at a small performance cost for all FFS file systems. 954See also 955.Xr newfs 8 , 956.Xr fsck_ffs 8 , 957.Xr dumpfs 8 958for file system byte order status and manipulation. 959.It Cd options FFS_NO_SNAPSHOT 960Disable the 961.Dq file system snapshot 962support in FFS file systems. 963Maybe useful for install media kernels, small memory systems and 964embedded systems which don't require the snapshot support. 965.It Cd options UFS_EXTATTR 966Enable extended attribute support for UFS1 filesystems. 967.It Cd options WAPBL 968Enable 969.Dq Write Ahead Physical Block Logging file system journaling . 970This provides rapid file system consistency checking after a system outage. 971It also provides better general use performance over regular FFS. 972See also 973.Xr wapbl 4 . 974.It Cd options NVNODE=integer 975This option sets the size of the cache used by the name-to-inode translation 976routines, (a.k.a. the 977.Fn namei 978cache, though called by many other names in the kernel source). 979By default, this cache has 980.Dv NPROC 981(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 982A reasonable way to derive a value of 983.Dv NVNODE , 984should you notice a large number of namei cache misses with a tool such as 985.Xr systat 1 , 986is to examine your system's current computed value with 987.Xr sysctl 8 , 988(which calls this parameter "kern.maxvnodes") and to increase this value 989until either the namei cache hit rate improves or it is determined that 990your system does not benefit substantially from an increase in the size of 991the namei cache. 992.It Cd options NAMECACHE_ENTER_REVERSE 993Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 994as well as a normal one. 995Normally, this is already done for directory vnodes, to speed up the getcwd 996operation. 997This option will cause longer hash chains in the reverse cache, and thus 998slow down getcwd somewhat. 999However, it does make vnode -\*[Gt] path translations possible in some cases. 1000For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1001required. 1002.It Cd options EXT2FS_SYSTEM_FLAGS 1003This option changes the behavior of the APPEND and IMMUTABLE flags 1004for a file on an 1005.Em ext2 1006file system. 1007Without this option, the superuser or owner of the file can 1008set and clear them. 1009With this option, only the superuser can set them, and 1010they can't be cleared if the securelevel is greater than 0. 1011See also 1012.Xr chflags 1 1013and 1014.Xr secmodel_securelevel 9 . 1015.It Cd options NFS_BOOT_BOOTP 1016Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1017information if NFS is used to mount the root file system. 1018See 1019.Xr diskless 8 1020for details. 1021.It Cd options NFS_BOOT_DHCP 1022Same as 1023.Dq NFS_BOOT_BOOTP , 1024but use the DHCP extensions to the 1025BOOTP protocol (RFC 1541). 1026.It Cd options NFS_BOOT_BOOTP_REQFILE 1027Specifies the string sent in the bp_file field of the BOOTP / DHCP 1028request packet. 1029.It Cd options NFS_BOOT_BOOTPARAM 1030Enable use of the BOOTPARAM protocol, consisting of RARP and 1031BOOTPARAM RPC, to get configuration information if NFS 1032is used to mount the root file system. 1033See 1034.Xr diskless 8 1035for details. 1036.It Cd options NFS_BOOT_RWSIZE=value 1037Set the initial NFS read and write sizes for diskless-boot requests. 1038The normal default is 8Kbytes. 1039This option provides a way to lower the value (e.g., to 1024 bytes) 1040as a workaround for buggy network interface cards or boot PROMs. 1041Once booted, the read and write request sizes can be increased by 1042remounting the file system. 1043See 1044.Xr mount_nfs 8 1045for details. 1046.It Cd options NFS_V2_ONLY 1047Reduce the size of the NFS client code by omitting code that's only required 1048for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1049servers. 1050.It Cd options UFS_DIRHASH 1051Increase lookup performance by maintaining in-core hash tables 1052for large directories. 1053.El 1054.Ss Buffer queue strategy options 1055The following options enable alternative buffer queue strategies. 1056.Bl -ohang 1057.It Cd options BUFQ_READPRIO 1058Enable experimental buffer queue strategy for disk I/O. 1059In the default strategy, outstanding disk requests are ordered by 1060sector number and sent to the disk, regardless of whether the 1061operation is a read or write; this option gives priority to issuing 1062read requests over write requests. 1063Although requests may therefore be issued out of sector-order, causing 1064more seeks and thus lower overall throughput, interactive system 1065responsiveness under heavy disk I/O load may be improved, as processes 1066blocking on disk reads are serviced sooner (file writes typically 1067don't cause applications to block). 1068The performance effect varies greatly depending on the hardware, drive 1069firmware, file system configuration, workload, and desired performance 1070trade-off. 1071Systems using drive write-cache (most modern IDE disks, by default) 1072are unlikely to benefit and may well suffer; such disks acknowledge 1073writes very quickly, and optimize them internally according to 1074physical layout. 1075Giving these disks as many requests to work with as possible (the 1076standard strategy) will typically produce the best results, especially 1077if the drive has a large cache; the drive will silently complete 1078writes from cache as it seeks for reads. 1079Disks that support a large number of concurrent tagged requests (SCSI 1080disks and many hardware RAID controllers) expose this internal 1081scheduling with tagged responses, and don't block for reads; such 1082disks may not see a noticeable difference with either strategy. 1083However, if IDE disks are run with write-cache disabled for safety, 1084writes are not acknowledged until actually completed, and only one 1085request can be outstanding; a large number of small writes in one 1086locality can keep the disk busy, starving reads elsewhere on the disk. 1087Such systems are likely to see the most benefit from this option. 1088Finally, the performance interaction of this option with ffs soft 1089dependencies can be subtle, as that mechanism can drastically alter 1090the workload for file system metadata writes. 1091.It Cd options BUFQ_PRIOCSCAN 1092Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1093.It Cd options NEW_BUFQ_STRATEGY 1094Synonym of 1095.Em BUFQ_READPRIO . 1096.El 1097.Ss Miscellaneous Options 1098.Bl -ohang 1099.It Cd options CPU_UCODE 1100Support cpu microcode loading via 1101.Xr cpuctl 8 . 1102.It Cd options MEMORY_DISK_DYNAMIC 1103This option makes the 1104.Xr md 4 1105.Tn RAM 1106disk size dynamically sized. 1107It is incompatible with 1108.Xr mdsetimage 8 . 1109.It Cd options MEMORY_DISK_HOOKS 1110This option allows for some machine dependent functions to be called when 1111the 1112.Xr md 4 1113.Tn RAM 1114disk driver is configured. 1115This can result in automatically loading a 1116.Tn RAM 1117disk from floppy on open (among other things). 1118.It Cd options MEMORY_DISK_IS_ROOT 1119Forces the 1120.Xr md 4 1121.Tn RAM 1122disk to be the root device. 1123This can only be overridden when 1124the kernel is booted in the 'ask-for-root' mode. 1125.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1126Allocates the given number of 512 byte blocks as memory for the 1127.Xr md 4 1128.Tn RAM 1129disk, to be populated with 1130.Xr mdsetimage 8 . 1131.It Cd options MEMORY_DISK_SERVER=0 1132Do not include the interface to a userland memory disk server process. 1133Per default, this option is set to 1, including the support code. 1134Useful for install media kernels. 1135.It Cd options MEMORY_DISK_RBFLAGS=value 1136This option sets the 1137.Xr reboot 2 1138flags used when booting with a memory disk as root file system. 1139Possible values include 1140.Dv RB_AUTOBOOT 1141(boot in the usual fashion - default value), and 1142.Dv RB_SINGLE 1143(boot in single-user mode). 1144.It Cd options MODULAR 1145Enables the framework for kernel modules (see 1146.Xr module 7 ) . 1147.It Cd options VND_COMPRESSION 1148Enables the 1149.Xr vnd 4 1150driver to also handle compressed images. 1151See 1152.Xr vndcompress 1 , 1153.Xr vnd 4 1154and 1155.Xr vnconfig 8 1156for more information. 1157.It Cd options SPLDEBUG 1158Help the kernel programmer find bugs related to the interrupt priority 1159level. 1160When 1161.Fn spllower 1162or 1163.Fn splraise 1164changes the current CPU's interrupt priority level to or from 1165.Dv IPL_HIGH , 1166record a backtrace. 1167Read 1168.Xr return_address 9 1169for caveats about collecting backtraces. 1170This feature is experimental, and it is only available on i386. 1171See 1172.Pa sys/kern/subr_spldebug.c . 1173.It Cd options TFTPROOT 1174Download the root memory disk through TFTP at root mount time. 1175This enables the use of a root 1176.Tn RAM 1177disk without requiring it to be embedded in the kernel using 1178.Xr mdsetimage 8 . 1179The 1180.Tn RAM 1181disk name is obtained using DHCP's filename parameter. 1182This option requires 1183.Em MEMORY_DISK_HOOKS , 1184.Em MEMORY_DISK_DYNAMIC , 1185and 1186.Em MEMORY_DISK_IS_ROOT . 1187It is incompatible with 1188.Em MEMORY_DISK_ROOT_SIZE . 1189.It Cd options MALLOC_NOINLINE 1190Time critical fixed size memory allocation is performed with 1191.Fn MALLOC 1192and 1193.Fn FREE . 1194Normally these expand to inline code, but with 1195.Em MALLOC_NOINLINE 1196these call the normal 1197.Fn malloc 1198and 1199.Fn free 1200functions. 1201Useful for install media kernels, small memory systems and embedded systems. 1202.It Cd options HZ=integer 1203On ports that support it, set the system clock frequency (see 1204.Xr hz 9 ) 1205to the supplied value. 1206Handle with care. 1207.It Cd options NTP 1208Turns on in-kernel precision timekeeping support used by software 1209implementing 1210.Em NTP 1211(Network Time Protocol, RFC 1305). 1212The 1213.Em NTP 1214option adds an in-kernel Phase-Locked Loop (PLL) for normal 1215.Em NTP 1216operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1217operation. 1218.Xr ntpd 8 1219will employ a user-level PLL when kernel support is unavailable, 1220but the in-kernel version has lower latency and more precision, and 1221so typically keeps much better time. 1222.Pp 1223The interface to the kernel 1224.Em NTP 1225support is provided by the 1226.Xr ntp_adjtime 2 1227and 1228.Xr ntp_gettime 2 1229system calls, which are intended for use by 1230.Xr ntpd 8 1231and are enabled by the option. 1232On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1233is not an integer, the 1234.Em NTP 1235option also enables extended-precision arithmetic to keep track of 1236fractional clock ticks at NTP time-format precision. 1237.It Cd options PPS_SYNC 1238This option enables a kernel serial line discipline for receiving time 1239phase signals from an external reference clock such as a radio clock. 1240.Po 1241The 1242.Em NTP 1243option (which see) must be on if the 1244.Em PPS_SYNC 1245option is used 1246.Pc . 1247Some reference clocks generate a Pulse Per Second (PPS) signal in 1248phase with their time source. 1249The 1250.Em PPS 1251line discipline receives this signal on either the data leads 1252or the DCD control lead of a serial port. 1253.Pp 1254.Em NTP 1255uses the PPS signal to discipline the local clock oscillator to a high 1256degree of precision (typically less than 50 microseconds in time and 12570.1 ppm in accuracy). 1258.Em PPS 1259can also generate a serial output pulse when the system receives a PPS 1260interrupt. 1261This can be used to measure the system interrupt latency and thus calibrate 1262.Em NTP 1263to account for it. 1264Using 1265.Em PPS 1266usually requires a gadget box 1267to convert from 1268.Tn TTL 1269to 1270.Tn RS-232 1271signal levels. 1272The gadget box and PPS are described in more detail in the HTML documentation 1273for 1274.Xr ntpd 8 1275in 1276.Pa /usr/share/doc/html/ntp . 1277.Pp 1278.Nx 1279currently supports this option in 1280.Xr com 4 1281and 1282.Xr zsc 4 . 1283.It Cd options SETUIDSCRIPTS 1284Allows scripts with the setuid bit set to execute as the effective 1285user rather than the real user, just like binary executables. 1286.Pp 1287.Em NOTE : 1288Using this option will also enable 1289.Em options FDSCRIPTS 1290.It Cd options FDSCRIPTS 1291Allows execution of scripts with the execute bit set, but not the 1292read bit, by opening the file and passing the file descriptor to 1293the shell, rather than the filename. 1294.Pp 1295.Em NOTE : 1296Execute only (non-readable) scripts will have 1297.Va argv[0] 1298set to 1299.Pa /dev/fd/* . 1300What this option allows as far as security is 1301concerned, is the ability to safely ensure that the correct script 1302is run by the interpreter, as it is passed as an already open file. 1303.It Cd options PUCCN 1304Enables treating serial ports found on PCI boards 1305.Xr puc 4 1306as potential console devices. 1307The method for choosing such a console device is port dependent. 1308.It Cd options RTC_OFFSET=integer 1309The kernel (and typically the hardware battery backed-up clock on 1310those machines that have one) keeps time in 1311.Em UTC 1312(Universal Coordinated Time, once known as 1313.Em GMT , 1314or Greenwich Mean Time) 1315and not in the time of the local time zone. 1316The 1317.Em RTC_OFFSET 1318option is used on some ports (such as the i386) to tell the kernel 1319that the hardware clock is offset from 1320.Em UTC 1321by the specified number of minutes. 1322This is typically used when a machine boots several operating 1323systems and one of them wants the hardware clock to run in the 1324local time zone and not in 1325.Em UTC , 1326e.g. 1327.Em RTC_OFFSET=300 1328means 1329the hardware clock is set to US Eastern Time (300 minutes behind 1330.Em UTC ) , 1331and not 1332.Em UTC . 1333(Note: 1334.Em RTC_OFFSET 1335is used to initialize a kernel variable named 1336.Va rtc_offset 1337which is the source actually used to determine the clock offset, and 1338which may be accessed via the kern.rtc_offset sysctl variable. 1339See 1340.Xr sysctl 8 1341and 1342.Xr sysctl 3 1343for details. 1344Since the kernel clock is initialized from the hardware clock very 1345early in the boot process, it is not possible to meaningfully change 1346.Va rtc_offset 1347in system initialization scripts. 1348Changing this value currently may only be done at kernel compile 1349time or by patching the kernel and rebooting). 1350.Pp 1351.Em NOTE : 1352Unfortunately, in many cases where the hardware clock 1353is kept in local time, it is adjusted for Daylight Savings 1354Time; this means that attempting to use 1355.Em RTC_OFFSET 1356to let 1357.Nx 1358coexist with such an operating system, like Windows, 1359would necessitate changing 1360.Em RTC_OFFSET 1361twice a year. 1362As such, this solution is imperfect. 1363.It Cd options KMEMSTATS 1364The kernel memory allocator, 1365.Xr malloc 9 , 1366will keep statistics on its performance if this option is enabled. 1367Unfortunately, this option therefore essentially disables the 1368.Fn MALLOC 1369and 1370.Fn FREE 1371forms of the memory allocator, which are used to enhance the performance 1372of certain critical sections of code in the kernel. 1373This option therefore can lead to a significant decrease in the 1374performance of certain code in the kernel if enabled. 1375Examples of such code include the 1376.Fn namei 1377routine, the 1378.Xr ccd 4 1379driver, 1380and much of the networking code. 1381.It Cd options MAXUPRC=integer 1382Sets the soft 1383.Dv RLIMIT_NPROC 1384resource limit, which specifies the maximum number of simultaneous 1385processes a user is permitted to run, for process 0; 1386this value is inherited by its child processes. 1387It defaults to 1388.Em CHILD_MAX , 1389which is currently defined to be 160. 1390Setting 1391.Em MAXUPRC 1392to a value less than 1393.Em CHILD_MAX 1394is not permitted, as this would result in a violation of the semantics of 1395.St -p1003.1-90 . 1396.It Cd options NOFILE=integer 1397Sets the soft 1398.Dv RLIMIT_NOFILE 1399resource limit, which specifies the maximum number of open 1400file descriptors for each process; 1401this value is inherited by its child processes. 1402It defaults to 1403.Em OPEN_MAX , 1404which is currently defined to be 64. 1405.It Cd options MAXFILES=integer 1406Sets the default value of the 1407.Em kern.maxfiles 1408sysctl variable, which indicates the maximum number of files that may 1409be open in the system. 1410.It Cd options DEFCORENAME=string 1411Sets the default value of the 1412.Em kern.defcorename 1413sysctl variable, otherwise it is set to 1414.Nm %n.core . 1415See 1416.Xr sysctl 8 1417and 1418.Xr sysctl 3 1419for details. 1420.It Cd options RASOPS_CLIPPING 1421Enables clipping within the 1422.Nm rasops 1423raster-console output system. 1424.Em NOTE : 1425only available on architectures that use 1426.Nm rasops 1427for console output. 1428.It Cd options RASOPS_SMALL 1429Removes optimized character writing code from the 1430.Nm rasops 1431raster-console output system. 1432.Em NOTE : 1433only available on architectures that use 1434.Nm rasops 1435for console output. 1436.It Cd options INCLUDE_CONFIG_FILE 1437Embeds the kernel config file used to define the kernel in the kernel 1438binary itself. 1439The embedded data also includes any files directly included by the config 1440file itself, e.g. 1441.Pa GENERIC.local 1442or 1443.Pa std.$MACHINE . 1444The embedded config file can be extracted from the resulting kernel with 1445.Xr config 1 1446.Fl x , 1447or by the following command: 1448.Bd -literal -offset indent 1449strings netbsd | sed -n 's/^_CFG_//p' | unvis 1450.Ed 1451.It Cd options INCLUDE_JUST_CONFIG 1452Similar to the above option, but includes just the actual config file, 1453not any included files. 1454.It Cd options PIPE_SOCKETPAIR 1455Use slower, but smaller socketpair(2)-based pipe implementation instead 1456of default faster, but bigger one. 1457Primarily useful for installation kernels. 1458.It Cd options USERCONF 1459Compiles in the in-kernel device configuration manager. 1460See 1461.Xr userconf 4 1462for details. 1463.It Cd options PERFCTRS 1464Compiles in kernel support for CPU performance-monitoring counters. 1465See 1466.Xr pmc 1 1467for details. 1468.Em NOTE : 1469not available on all architectures. 1470.It Cd options SYSCALL_STATS 1471Count the number of times each system call number is called. 1472The values can be read through the sysctl interface and displayed using 1473.Xr systat 1 . 1474.Em NOTE : 1475not yet available on all architectures. 1476.It Cd options SYSCALL_TIMES 1477Count the time spent (using 1478.Fn cpu_counter32 ) 1479in each system call. 1480.Em NOTE : 1481Using this option will also enable 1482.Cd options SYSCALL_STATS . 1483.It Cd options SYSCALL_TIMES_HASCOUNTER 1484Force use of 1485.Fn cpu_counter32 1486even if 1487.Fn cpu_hascounter 1488reports false. 1489Useful for systems where the cycle counter doesn't run at a constant rate 1490(e.g. Soekris boxes). 1491.It Cd options XSERVER_DDB 1492A supplement to XSERVER that adds support for entering 1493.Xr ddb 4 1494while in 1495.Tn X11 . 1496.It Cd options FILEASSOC 1497Support for 1498.Xr fileassoc 9 . 1499.It Cd options FILEASSOC_NHOOKS=integer 1500Number of storage slots per file for 1501.Xr fileassoc 9 . 1502Default is 4. 1503.El 1504.Ss Networking Options 1505.Bl -ohang 1506.It Cd options GATEWAY 1507Enables 1508.Em IPFORWARDING 1509(which see) 1510and (on most ports) increases the size of 1511.Em NMBCLUSTERS 1512(which see). 1513In general, 1514.Em GATEWAY 1515is used to indicate that a system should act as a router, and 1516.Em IPFORWARDING 1517is not invoked directly. 1518(Note that 1519.Em GATEWAY 1520has no impact on protocols other than 1521.Tn IP , 1522such as 1523.Tn CLNP ) . 1524.Em GATEWAY 1525option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1526.It Cd options ICMPPRINTFS 1527The 1528.Em ICMPPRINTFS 1529option will enable debugging information to be printed about 1530the 1531.Xr icmp 4 1532protocol. 1533.It Cd options IPFORWARDING=value 1534If 1535.Em value 1536is 1 this enables IP routing behavior. 1537If 1538.Em value 1539is 0 (the default), it disables it. 1540The 1541.Em GATEWAY 1542option sets this to 1 automatically. 1543With this option enabled, the machine will forward IP datagrams destined 1544for other machines between its interfaces. 1545Note that even without this option, the kernel will 1546still forward some packets (such as source routed packets) -- removing 1547.Em GATEWAY 1548and 1549.Em IPFORWARDING 1550is insufficient to stop all routing through a bastion host on a 1551firewall -- source routing is controlled independently. 1552To turn off source routing, use 1553.Em options IPFORWSRCRT=0 1554(which see). 1555Note that IP forwarding may be turned on and off independently of the 1556setting of the 1557.Em IPFORWARDING 1558option through the use of the 1559.Em net.inet.ip.forwarding 1560sysctl variable. 1561If 1562.Em net.inet.ip.forwarding 1563is 1, IP forwarding is on. 1564See 1565.Xr sysctl 8 1566and 1567.Xr sysctl 3 1568for details. 1569.It Cd options IPFORWSRCRT=value 1570If 1571.Em value 1572is set to zero, source routing of IP datagrams is turned off. 1573If 1574.Em value 1575is set to one (the default) or the option is absent, source routed IP 1576datagrams are forwarded by the machine. 1577Note that source routing of IP packets may be turned on and off 1578independently of the setting of the 1579.Em IPFORWSRCRT 1580option through the use of the 1581.Em net.inet.ip.forwsrcrt 1582sysctl variable. 1583If 1584.Em net.inet.ip.forwsrcrt 1585is 1, forwarding of source routed IP datagrams is on. 1586See 1587.Xr sysctl 8 1588and 1589.Xr sysctl 3 1590for details. 1591.It Cd options IFA_STATS 1592Tells the kernel to maintain per-address statistics on bytes sent 1593and received over (currently) Internet and AppleTalk addresses. 1594.\"This can be a fairly expensive operation, so you probably want to 1595.\"keep this disabled. 1596The option is not recommended as it degrades system stability. 1597.It Cd options IFQ_MAXLEN=value 1598Increases the allowed size of the network interface packet queues. 1599The default queue size is 50 packets, and you do not normally need 1600to increase it. 1601.It Cd options IPSELSRC 1602Includes support for source-address selection policies. 1603See 1604.Xr in_getifa 9 . 1605.It Cd options MROUTING 1606Includes support for IP multicast routers. 1607You certainly want 1608.Em INET 1609with this. 1610Multicast routing is controlled by the 1611.Xr mrouted 8 1612daemon. 1613See also option 1614.Cd PIM . 1615.It Cd options PIM 1616Includes support for Protocol Independent Multicast (PIM) routing. 1617You need 1618.Em MROUTING 1619and 1620.Em INET 1621with this. 1622Software using this can be found e.g. in 1623.Pa pkgsrc/net/xorp . 1624.It Cd options INET 1625Includes support for the 1626.Tn TCP/IP 1627protocol stack. 1628You almost certainly want this. 1629See 1630.Xr inet 4 1631for details. 1632.It Cd options INET6 1633Includes support for the 1634.Tn IPv6 1635protocol stack. 1636See 1637.Xr inet6 4 1638for details. 1639Unlike 1640.Em INET , 1641.Em INET6 1642enables multicast routing code as well. 1643This option requires 1644.Em INET 1645at this moment, but it should not. 1646.It Cd options ND6_DEBUG 1647The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1648for debugging IPv6 neighbor discovery protocol handling. 1649See 1650.Xr sysctl 3 1651for details. 1652.It Cd options IPSEC 1653Includes support for the 1654.Tn IPsec 1655protocol, using the FAST_IPSEC implementation. 1656See 1657.Xr fast_ipsec 4 1658for details. 1659(This option is an alias for the 1660.Cd FAST_IPSEC 1661option described below.) 1662.It Cd options IPSEC_DEBUG 1663Enables debugging code in 1664.Tn IPsec 1665stack. 1666See 1667.Xr ipsec 4 1668for details. 1669.It Cd options FAST_IPSEC 1670Includes support for the 1671.Tn IPsec 1672protocol, using the implementation derived from 1673.Ox , 1674relaying on 1675.Xr opencrypto 9 1676to carry out cryptographic operations. 1677See 1678.Xr fast_ipsec 4 1679for details. 1680.It Cd options IPSEC_NAT_T 1681Includes support for 1682.Tn IPsec 1683Network Address Translator traversal (NAT-T), as described in RFCs 3947 1684and 3948. 1685This feature might be patent-encumbered in some countries. 1686.It Cd options ALTQ 1687Enabled ALTQ (Alternate Queueing). 1688For simple rate-limiting, use 1689.Xr tbrconfig 8 1690to set up the interface transmission rate. 1691To use queueing disciplines, their appropriate kernel options should also 1692be defined (documented below). 1693Queueing disciplines are managed by 1694.Xr altqd 8 . 1695See 1696.Xr altq 9 1697for details. 1698.It Cd options ALTQ_HFSC 1699Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1700module. 1701HFSC supports both link-sharing and guaranteed real-time services. 1702HFSC employs a service curve based QoS model, and its unique feature 1703is an ability to decouple delay and bandwidth allocation. 1704Requires 1705.Em ALTQ_RED 1706to use the RED queueing discipline on HFSC classes, or 1707.Em ALTQ_RIO 1708to use the RIO queueing discipline on HFSC classes. 1709This option assumes 1710.Em ALTQ . 1711.It Cd options ALTQ_PRIQ 1712Include support for ALTQ-implemented PRIQ (Priority Queueing). 1713PRIQ implements a simple priority-based queueing discipline. 1714A higher priority class is always served first. 1715Requires 1716.Em ALTQ_RED 1717to use the RED queueing discipline on HFSC classes, or 1718.Em ALTQ_RIO 1719to use the RIO queueing discipline on HFSC classes. 1720This option assumes 1721.Em ALTQ . 1722.It Cd options ALTQ_WFQ 1723Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1724WFQ implements a weighted-round robin scheduler for a set of queues. 1725A weight can be assigned to each queue to give a different proportion 1726of the link capacity. 1727A hash function is used to map a flow to one of a set of queues. 1728This option assumes 1729.Em ALTQ . 1730.It Cd options ALTQ_FIFOQ 1731Include support for ALTQ-implemented FIFO queueing. 1732FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1733This option assumes 1734.Em ALTQ . 1735.It Cd options ALTQ_RIO 1736Include support for ALTQ-implemented RIO (RED with In/Out). 1737The original RIO has 2 sets of RED parameters; one for in-profile 1738packets and the other for out-of-profile packets. 1739At the ingress of the network, profile meters tag packets as IN or 1740OUT based on contracted profiles for customers. 1741Inside the network, IN packets receive preferential treatment by 1742the RIO dropper. 1743ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1744PHB of DiffServ (RFC 2597). 1745This option assumes 1746.Em ALTQ . 1747.It Cd options ALTQ_BLUE 1748Include support for ALTQ-implemented Blue buffer management. 1749Blue is another active buffer management mechanism. 1750This option assumes 1751.Em ALTQ . 1752.It Cd options ALTQ_FLOWVALVE 1753Include support for ALTQ-implemented Flowvalve. 1754Flowvalve is a simple implementation of a RED penalty box that identifies 1755and punishes misbehaving flows. 1756This option requires 1757.Em ALTQ_RED 1758and assumes 1759.Em ALTQ . 1760.It Cd options ALTQ_CDNR 1761Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1762packet marking/manipulation. 1763Traffic conditioners are components to meter, mark, or drop incoming 1764packets according to some rules. 1765As opposed to queueing disciplines, traffic conditioners handle incoming 1766packets at an input interface. 1767This option assumes 1768.Em ALTQ . 1769.It Cd options ALTQ_NOPCC 1770Disables use of processor cycle counter to measure time in ALTQ. 1771This option should be defined for a non-Pentium i386 CPU which does not 1772have TSC, SMP (per-CPU counters are not in sync), or power management 1773which affects processor cycle counter. 1774This option assumes 1775.Em ALTQ . 1776.It Cd options ALTQ_IPSEC 1777Include support for IPsec in IPv4 ALTQ. 1778This option assumes 1779.Em ALTQ . 1780.It Cd options ALTQ_JOBS 1781Include support for ALTQ-implemented JoBS (Joint Buffer Management 1782and Scheduling). 1783This option assumes 1784.Em ALTQ . 1785.It Cd options ALTQ_AFMAP 1786Include support for an undocumented ALTQ feature that is used to map an IP 1787flow to an ATM VC (Virtual Circuit). 1788This option assumes 1789.Em ALTQ . 1790.It Cd options ALTQ_LOCALQ 1791Include support for ALTQ-implemented local queues. 1792Its practical use is undefined. 1793Assumes 1794.Em ALTQ . 1795.It Cd options SUBNETSARELOCAL 1796Sets default value for net.inet.ip.subnetsarelocal variable, which 1797controls whether non-directly-connected subnets of connected networks 1798are considered "local" for purposes of choosing the MSS for a TCP 1799connection. 1800This is mostly present for historic reasons and completely irrelevant if 1801you enable Path MTU discovery. 1802.It Cd options HOSTZEROBROADCAST 1803Sets default value for net.inet.ip.hostzerobroadcast variable, which 1804controls whether the zeroth host address of each connected subnet is 1805also considered a broadcast address. 1806Default value is "1", for compatibility with old systems; if this is 1807set to zero on all hosts on a subnet, you should be able to fit an extra 1808host per subnet on the 1809".0" address. 1810.It Cd options MCLSHIFT=value 1811This option is the base-2 logarithm of the size of mbuf clusters. 1812The 1813.Bx 1814networking stack keeps network packets in a linked 1815list, or chain, of kernel buffer objects called mbufs. 1816The system provides larger mbuf clusters as an optimization for 1817large packets, instead of using long chains for large packets. 1818The mbuf cluster size, 1819or 1820.Em MCLBYTES , 1821must be a power of two, and is computed as two raised to the power 1822.Em MCLSHIFT . 1823On systems with Ethernet network adapters, 1824.Em MCLSHIFT 1825is often set to 11, giving 2048-byte mbuf clusters, large enough to 1826hold a 1500-byte 1827.Tn Ethernet 1828frame in a single cluster. 1829Systems with network interfaces supporting larger frame sizes like 1830.Tn ATM , 1831.Tn FDDI , 1832or 1833.Tn HIPPI 1834may perform better with 1835.Em MCLSHIFT 1836set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1837respectively. 1838.It Cd options ISO,TPIP 1839Include support for the ubiquitous 1840.Tn OSI 1841protocol stack. 1842See 1843.Xr iso 4 1844for details. 1845This option assumes 1846.Em INET . 1847.It Cd options EON 1848Include support for tunneling 1849.Tn OSI 1850protocols over 1851.Tn IP . 1852Known to be broken, or at least very fragile, and undocumented. 1853.It Cd options NETATALK 1854Include support for the 1855.Tn AppleTalk 1856protocol stack. 1857The kernel provides provision for the 1858.Em Datagram Delivery Protocol 1859(DDP), providing SOCK_DGRAM support and 1860.Tn AppleTalk 1861routing. 1862This stack is used by the 1863.Em NETATALK 1864package, which adds support for 1865.Tn AppleTalk 1866server services via user libraries and applications. 1867.It Cd options BLUETOOTH 1868Include support for the 1869.Tn Bluetooth 1870protocol stack. 1871See 1872.Xr bluetooth 4 1873for details. 1874.It Cd options IPNOPRIVPORTS 1875Normally, only root can bind a socket descriptor to a so-called 1876.Dq privileged 1877.Tn TCP 1878port, that is, a port number in the range 0-1023. 1879This option eliminates those checks from the kernel. 1880This can be useful if there is a desire to allow daemons without 1881privileges to bind those ports, e.g., on firewalls. 1882The security tradeoffs in doing this are subtle. 1883This option should only be used by experts. 1884.It Cd options TCP_COMPAT_42 1885.Tn TCP 1886bug compatibility with 1887.Bx 4.2 . 1888In 1889.Bx 4.2 , 1890.Tn TCP 1891sequence numbers were 32-bit signed values. 1892Modern implementations of TCP use unsigned values. 1893This option clamps the initial sequence number to start in 1894the range 2^31 rather than the full unsigned range of 2^32. 1895Also, under 1896.Bx 4.2 , 1897keepalive packets must contain at least one byte or else 1898the remote end would not respond. 1899.It Cd options TCP_DEBUG 1900Record the last 1901.Em TCP_NDEBUG 1902TCP packets with SO_DEBUG set, and decode to the console if 1903.Em tcpconsdebug 1904is set. 1905.It Cd options TCP_NDEBUG 1906Number of packets to record for 1907.Em TCP_DEBUG . 1908Defaults to 100. 1909.It Cd options TCP_SENDSPACE=value 1910.It Cd options TCP_RECVSPACE=value 1911These options set the max TCP window size to other sizes than the default. 1912The TCP window sizes can be altered via 1913.Xr sysctl 8 1914as well. 1915.It Cd options TCP_INIT_WIN=value 1916This option sets the initial TCP window size for non-local connections, 1917which is used when the transmission starts. 1918The default size is 1, but if the machine should act more aggressively, 1919the initial size can be set to some other value. 1920The initial TCP window size can be set via 1921.Xr sysctl 8 1922as well. 1923.It Cd options PFIL_HOOKS 1924This option turns on the packet filter interface hooks. 1925See 1926.Xr pfil 9 1927for details. 1928This option assumes 1929.Em INET . 1930.It Cd options IPFILTER_LOG 1931This option, in conjunction with 1932.Em pseudo-device ipfilter , 1933enables logging of IP packets using IP-Filter. 1934.It Cd options IPFILTER_LOOKUP 1935This option enables the 1936IP-Filter 1937.Xr ippool 8 1938functionality to be enabled. 1939.It Cd options IPFILTER_COMPAT 1940This option enables older IP-Filter binaries to work. 1941.It Cd options IPFILTER_DEFAULT_BLOCK 1942This option sets the default policy of IP-Filter. 1943If it is set, IP-Filter will block packets by default. 1944.It Cd options BRIDGE_IPF 1945This option causes 1946.Em bridge 1947devices to use the IP and/or IPv6 filtering hooks, forming 1948a link-layer filter that uses protocol-layer rules. 1949This option assumes the presence of 1950.Em pseudo-device ipfilter . 1951.It Cd options MBUFTRACE 1952This option can help track down mbuf leaks. 1953When enabled, mbufs are tagged with the devices and protocols using them, 1954which slightly decreases network performance. 1955This additional information can be viewed with 1956.Xr netstat 1 : 1957.Dl Ic netstat Fl mssv 1958Not all devices or protocols support this option. 1959.El 1960.Ss Sysctl Related Options 1961.Bl -ohang 1962.It Cd options SYSCTL_DISALLOW_CREATE 1963Disallows the creation or deletion of nodes from the sysctl tree, as 1964well as the assigning of descriptions to nodes that lack them, by any 1965process. 1966These operations are still available to kernel sub-systems, including 1967loadable kernel modules. 1968.It Cd options SYSCTL_DISALLOW_KWRITE 1969Prevents processes from adding nodes to the sysctl tree that make 1970existing kernel memory areas writable. 1971Sections of kernel memory can still be read and new nodes that own 1972their own data may still be writable. 1973.It Cd options SYSCTL_DEBUG_SETUP 1974Causes the SYSCTL_SETUP routines to print a brief message when they 1975are invoked. 1976This is merely meant as an aid in determining the order in which 1977sections of the tree are created. 1978.It Cd options SYSCTL_DEBUG_CREATE 1979Prints a message each time 1980.Fn sysctl_create , 1981the function that adds nodes to the tree, is called. 1982.It Cd options SYSCTL_INCLUDE_DESCR 1983Causes the kernel to include short, human readable descriptions for 1984nodes in the sysctl tree. 1985The descriptions can be retrieved programmatically (see 1986.Xr sysctl 3 ) , 1987or by the sysctl binary itself (see 1988.Xr sysctl 8 ) . 1989The descriptions are meant to give an indication of the purpose and/or 1990effects of a given node's value, not replace the documentation for the 1991given subsystem as a whole. 1992.El 1993.Ss System V IPC Options 1994.Bl -ohang 1995.It Cd options SYSVMSG 1996Includes support for 1997.At V 1998style message queues. 1999See 2000.Xr msgctl 2 , 2001.Xr msgget 2 , 2002.Xr msgrcv 2 , 2003.Xr msgsnd 2 . 2004.It Cd options SYSVSEM 2005Includes support for 2006.At V 2007style semaphores. 2008See 2009.Xr semctl 2 , 2010.Xr semget 2 , 2011.Xr semop 2 . 2012.It Cd options SEMMNI=value 2013Sets the number of 2014.At V 2015style semaphore identifiers. 2016The GENERIC config file for your port will have the default. 2017.It Cd options SEMMNS=value 2018Sets the number of 2019.At V 2020style semaphores in the system. 2021The GENERIC config file for your port will have the default. 2022.It Cd options SEMUME=value 2023Sets the maximum number of undo entries per process for 2024.At V 2025style semaphores. 2026The GENERIC config file for your port will have the default. 2027.It Cd options SEMMNU=value 2028Sets the number of undo structures in the system for 2029.At V 2030style semaphores. 2031The GENERIC config file for your port will have the default. 2032.It Cd options SYSVSHM 2033Includes support for 2034.At V 2035style shared memory. 2036See 2037.Xr shmat 2 , 2038.Xr shmctl 2 , 2039.Xr shmdt 2 , 2040.Xr shmget 2 . 2041.It Cd options SHMMAXPGS=value 2042Sets the maximum number of 2043.At V 2044style shared memory pages that are available through the 2045.Xr shmget 2 2046system call. 2047Default value is 1024 on most ports. 2048See 2049.Pa /usr/include/machine/vmparam.h 2050for the default. 2051.El 2052.Ss VM Related Options 2053.Bl -ohang 2054.It Cd options NMBCLUSTERS=value 2055The number of mbuf clusters the kernel supports. 2056Mbuf clusters are MCLBYTES in size (usually 2k). 2057This is used to compute the size of the kernel VM map 2058.Em mb_map , 2059which maps mbuf clusters. 2060Default on most ports is 1024 (2048 with 2061.Dq options GATEWAY 2062). 2063See 2064.Pa /usr/include/machine/param.h 2065for exact default information. 2066Increase this value if you get 2067.Dq mclpool limit reached 2068messages. 2069.It Cd options NKMEMPAGES=value 2070.It Cd options NKMEMPAGES_MIN=value 2071.It Cd options NKMEMPAGES_MAX=value 2072Size of kernel VM map 2073.Em kmem_map , 2074in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2075from the 2076.Xr sysctl 8 2077variable 2078.Em hw.pagesize 2079). 2080This VM map is used to map the kernel malloc arena. 2081The kernel attempts to auto-size this map based on the amount of 2082physical memory in the system. 2083Platform-specific code may place bounds on this computed size, 2084which may be viewed with the 2085.Xr sysctl 8 2086variable 2087.Em vm.nkmempages . 2088See 2089.Pa /usr/include/machine/param.h 2090for the default upper and lower bounds. 2091The related options 2092.Sq NKMEMPAGES_MIN 2093and 2094.Sq NKMEMPAGES_MAX 2095allow the bounds to be overridden in the kernel configuration file. 2096These options are provided in the event the computed value is 2097insufficient resulting in an 2098.Dq out of space in kmem_map 2099panic. 2100.It Cd options SB_MAX=value 2101Sets the max size in bytes that a socket buffer is allowed to occupy. 2102The default is 256k, but sometimes it needs to be increased, for example 2103when using large TCP windows. 2104This option can be changed via 2105.Xr sysctl 8 2106as well. 2107.It Cd options SOMAXKVA=value 2108Sets the maximum size of kernel virtual memory that the socket buffers 2109are allowed to use. 2110The default is 16MB, but in situations where for example large TCP 2111windows are used this value must also be increased. 2112This option can be changed via 2113.Xr sysctl 8 2114as well. 2115.It Cd options BUFCACHE=value 2116Size of the buffer cache as a percentage of total available 2117.Tn RAM . 2118Ignored if BUFPAGES is also specified. 2119.It Cd options NBUF=value 2120Sets the number of buffer headers available, i.e., the number of 2121open files that may have a buffer cache entry. 2122Each buffer header 2123requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2124The default value is machine dependent, but is usually equal to the 2125value of BUFPAGES. 2126If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2127then NBUF may be reduced at run time so that the storage allocated 2128for buffer headers doesn't exceed that limit. 2129.It Cd options BUFPAGES=value 2130These options set the number of pages available for the buffer cache. 2131Their default value is a machine dependent value, often calculated as 2132between 5% and 10% of total available 2133.Tn RAM . 2134.It Cd options MAXTSIZ=bytes 2135Sets the maximum size limit of a process' text segment. 2136See 2137.Pa /usr/include/machine/vmparam.h 2138for the port-specific default. 2139.It Cd options DFLDSIZ=bytes 2140Sets the default size limit of a process' data segment, the value that 2141will be returned as the soft limit for 2142.Dv RLIMIT_DATA 2143(as returned by 2144.Xr getrlimit 2 ) . 2145See 2146.Pa /usr/include/machine/vmparam.h 2147for the port-specific default. 2148.It Cd options MAXDSIZ=bytes 2149Sets the maximum size limit of a process' data segment, the value that 2150will be returned as the hard limit for 2151.Dv RLIMIT_DATA 2152(as returned by 2153.Xr getrlimit 2 ) . 2154See 2155.Pa /usr/include/machine/vmparam.h 2156for the port-specific default. 2157.It Cd options DFLSSIZ=bytes 2158Sets the default size limit of a process' stack segment, the value that 2159will be returned as the soft limit for 2160.Dv RLIMIT_STACK 2161(as returned by 2162.Xr getrlimit 2 ) . 2163See 2164.Pa /usr/include/machine/vmparam.h 2165for the port-specific default. 2166.It Cd options MAXSSIZ=bytes 2167Sets the maximum size limit of a process' stack segment, the value that 2168will be returned as the hard limit for 2169.Dv RLIMIT_STACK 2170(as returned by 2171.Xr getrlimit 2 ) . 2172See 2173.Pa /usr/include/machine/vmparam.h 2174for the port-specific default. 2175.It Cd options DUMP_ON_PANIC=integer 2176Defaults to one. 2177If set to zero, the kernel will not dump to the dump device when 2178it panics, though dumps can still be forced via 2179.Xr ddb 4 2180with the 2181.Dq sync 2182command. 2183Note that this sets the value of the 2184.Em kern.dump_on_panic 2185.Xr sysctl 3 2186variable which may be changed at run time -- see 2187.Xr sysctl 8 2188for details. 2189.It Cd options USE_TOPDOWN_VM 2190User space memory allocations (as made by 2191.Xr mmap 2 ) 2192will be arranged in a 2193.Dq top down 2194fashion instead of the traditional 2195.Dq upwards from MAXDSIZ \&+ vm_daddr 2196method. 2197This includes the placement of 2198.Xr ld.so 1 . 2199Arranging memory in this manner allows either (or both of) the heap or 2200.Xr mmap 2 2201allocated space to grow larger than traditionally possible. 2202This option is not available on all ports, but is instead expected to be 2203offered on a port-by-port basis, after which some ports will commit to 2204using it by default. 2205See the files 2206.Pa /usr/include/uvm/uvm_param.h 2207for some implementation details, and 2208.Pa /usr/include/machine/vmparam.h 2209for port specific details including availability. 2210.It Cd options VMSWAP 2211Enable paging device/file support. 2212This option is on by default. 2213.It Cd options PDPOLICY_CLOCKPRO 2214Use CLOCK-Pro, an alternative page replace policy. 2215.El 2216.Ss Security Options 2217.Bl -ohang 2218.It Cd options INSECURE 2219Hardwires the kernel security level at \-1. 2220This means that the system 2221always runs in secure level \-1 mode, even when running multiuser. 2222See the manual page for 2223.Xr init 8 2224for details on the implications of this. 2225The kernel secure level may manipulated by the superuser by altering the 2226.Em kern.securelevel 2227.Xr sysctl 3 2228variable (the secure level may only be lowered by a call from process ID 1, 2229i.e., 2230.Xr init 8 ) . 2231See also 2232.Xr secmodel_securelevel 9 , 2233.Xr sysctl 8 2234and 2235.Xr sysctl 3 . 2236.It Cd options VERIFIED_EXEC_FP_MD5 2237Enables support for MD5 hashes in Veriexec. 2238.It Cd options VERIFIED_EXEC_FP_SHA1 2239Enables support for SHA1 hashes in Veriexec. 2240.It Cd options VERIFIED_EXEC_FP_RMD160 2241Enables support for RMD160 hashes in Veriexec. 2242.It Cd options VERIFIED_EXEC_FP_SHA256 2243Enables support for SHA256 hashes in Veriexec. 2244.It Cd options VERIFIED_EXEC_FP_SHA384 2245Enables support for SHA384 hashes in Veriexec. 2246.It Cd options VERIFIED_EXEC_FP_SHA512 2247Enables support for SHA512 hashes in Veriexec. 2248.It Cd options PAX_MPROTECT=value 2249Enables PaX MPROTECT, 2250.Xr mprotect 2 2251restrictions from the PaX project. 2252.Pp 2253The 2254.Ar value 2255is the default value for the 2256.Em global 2257knob, see 2258.Xr sysctl 3 . 2259If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2260using 2261.Xr paxctl 8 . 2262If 1, PaX MPROTECT will be enabled for all programs. 2263Programs can be exempted using 2264.Xr paxctl 8 . 2265.Pp 2266See 2267.Xr security 7 2268for more details. 2269.It Cd options PAX_SEGVGUARD=value 2270Enables PaX Segvguard. 2271.Pp 2272The 2273.Ar value 2274is the default value for the 2275.Em global 2276knob, see 2277.Xr sysctl 3 . 2278If 0, PaX Segvguard will be enabled only if explicitly set on programs 2279using 2280.Xr paxctl 8 . 2281If 1, PaX Segvguard will be enabled to all programs, and exemption can 2282be done using 2283.Xr paxctl 8 . 2284.Pp 2285See 2286.Xr security 7 2287for more details. 2288.It Cd options PAX_ASLR=value 2289Enables PaX ASLR. 2290.Pp 2291The 2292.Ar value 2293is the default value for the 2294.Em global 2295knob, see 2296.Xr sysctl 3 . 2297If 0, PaX ASLR will be enabled only if explicitly set on programs 2298using 2299.Xr paxctl 8 . 2300If 1, PaX ASLR will be enabled to all programs, and exemption can 2301be done using 2302.Xr paxctl 8 . 2303.Pp 2304See 2305.Xr security 7 2306for more details. 2307.It Cd options USER_VA0_DISABLE_DEFAULT=value 2308Sets the initial value of the flag which controls whether user programs 2309can map virtual address 0. 2310The flag can be changed at runtime by 2311.Xr sysctl 3 . 2312.El 2313.Ss amiga-specific Options 2314.Bl -ohang 2315.It Cd options BB060STUPIDROM 2316When the bootloader (which passes 2317.Tn AmigaOS 2318.Tn ROM 2319information) claims we have a 68060 2320.Tn CPU 2321without 2322.Tn FPU , 2323go look into the Processor Configuration Register (PCR) to find out. 2324You need this with 2325.Tn Amiga 2326.Tn ROM Ns s 2327up to (at least) V40.xxx (OS3.1), 2328when you boot via the bootblocks and don't have a DraCo. 2329.It Cd options IOBZCLOCK=frequency 2330The IOBlix boards come with two different serial master clocks: older ones 2331use 24 MHz, newer ones use 22.1184 MHz. 2332The driver normally assumes the latter. 2333If your board uses 24 MHz, you can recompile your kernel with 2334options IOBZCLOCK=24000000 2335or patch the kernel variable 2336.Tn iobzclock 2337to the same value. 2338.It Cd options LIMITMEM=value 2339If there, limit the part of the first memory bank used by 2340.Nx 2341to value megabytes. 2342Default is unlimited. 2343.It Cd options NKPTADD=addvalue 2344.It Cd options NKPTADDSHIFT=shiftvalue 2345The 2346.Tn CPU 2347specific 2348.Tn MMU 2349table for the kernel is pre-allocated at kernel startup time. 2350Part of it is scaled with 2351.Va maxproc , 2352to have enough room to hold the user program 2353.Tn MMU 2354tables; the second part is a fixed amount for the kernel itself. 2355.Pp 2356The third part accounts for the size of the file buffer cache. 2357Its size is either 2358.Dv NKPTADD 2359pages (if defined) or memory size in bytes divided by two to 2360the power of 2361.Dv NKPTADDSHIFT . 2362The default is undefined 2363.Dv NKPTADD 2364and 2365.Dv NKPTADDSHIFT=24 , 2366allowing for 16 buffers per megabyte of main memory (while 2367a GENERIC kernel allocates about half of that). 2368When you get "can't get KPT page" panics, you should increase 2369.Dv NKPTADD 2370(if defined), or decrease 2371.Dv NKPTADDSHIFT 2372by one. 2373.It Cd options P5PPC68KBOARD 2374Add special support for Phase5 mixed 68k+PPC boards. 2375Currently, this only affects rebooting from 2376.Nx 2377and is only needed on 68040+PPC, not on 237868060+PPC; without this, affected machines will hang after 2379.Nx 2380has shut 2381down and will only restart after a keyboard reset or a power cycle. 2382.El 2383.Ss atari-specific Options 2384.Bl -ohang 2385.It Cd options DISKLABEL_AHDI 2386Include support for AHDI (native Atari) disklabels. 2387.It Cd options DISKLABEL_NBDA 2388Include support for 2389.Nx Ns Tn /atari 2390labels. 2391If you don't set this option, it will be set automatically. 2392.Nx Ns Tn /atari 2393will not work without it. 2394.It Cd options FALCON_SCSI 2395Include support for the 5380-SCSI configuration as found on the Falcon. 2396.It Cd options RELOC_KERNEL 2397If set, the kernel will relocate itself to TT-RAM, if possible. 2398This will give you a slightly faster system. 2399.Em Beware 2400that on some TT030 systems, 2401the system will frequently dump with MMU-faults with this option enabled. 2402.It Cd options SERCONSOLE 2403Allow the modem1-port to act as the system-console. 2404A carrier should be active on modem1 during system boot to active 2405the console functionality. 2406.It Cd options TT_SCSI 2407Include support for the 5380-SCSI configuration as found on the TT030 2408and Hades. 2409.El 2410.Ss i386-specific Options 2411.Bl -ohang 2412.It Cd options CPURESET_DELAY=value 2413Specifies the time (in millisecond) to wait before doing a hardware reset 2414in the last phase of a reboot. 2415This gives the user a chance to see error messages from the shutdown 2416operations (like NFS unmounts, buffer cache flush, etc ...). 2417Setting this to 0 will disable the delay. 2418Default is 2 seconds. 2419.It Cd options VM86 2420Include support for virtual 8086 mode, used by 2421.Tn DOS 2422emulators and X servers to run BIOS code, e.g., for some VESA routines. 2423.It Cd options USER_LDT 2424Include i386-specific system calls for modifying the local descriptor table, 2425used by Windows emulators. 2426.It Cd options PAE 2427Enable 2428.Tn PAE (Physical Address Extension) 2429mode. 2430.Tn PAE 2431permits up to 36 bits physical addressing (64GB of physical memory), and 2432turns physical addresses to 64 bits entities in the memory management 2433subsystem. 2434Userland virtual address space remains at 32 bits (4GB). 2435.Tn PAE 2436mode is required to enable the 2437.Tn NX/XD (No-eXecute/eXecute Disable) 2438bit for pages, which allows marking certain ones as not being executable. 2439Any attempt to execute code from such a page will raise an exception. 2440.It Cd options REALBASEMEM=integer 2441Overrides the base memory size passed in from the boot block. 2442(Value given in kilobytes.) 2443Use this option only if the boot block reports the size incorrectly. 2444(Note that some 2445.Tn BIOS Ns es 2446put the extended 2447.Tn BIOS 2448data area at the top of base memory, and therefore report a smaller 2449base memory size to prevent programs overwriting it. 2450This is correct behavior, and you should not use the 2451.Em REALBASEMEM 2452option to access this memory). 2453.It Cd options REALEXTMEM=integer 2454Overrides the extended memory size passed in from the boot block. 2455(Value given in kilobytes. 2456Extended memory does not include the first megabyte.) 2457Use this option only if the boot block reports the size incorrectly. 2458.It Cd options CYRIX_CACHE_WORKS 2459Relevant only to the Cyrix 486DLC CPU. 2460This option is used to turn on the cache in hold-flush mode. 2461It is not turned on by default because it is known to have problems in 2462certain motherboard implementations. 2463.It Cd options CYRIX_CACHE_REALLY_WORKS 2464Relevant only to the Cyrix 486DLC CPU. 2465This option is used to turn on the cache in write-back mode. 2466It is not turned on by default because it is known to have problems in 2467certain motherboard implementations. 2468In order for this option to take effect, option 2469.Em CYRIX_CACHE_WORKS 2470must also be specified. 2471.It Cd options PCIBIOS 2472Enable support for initializing the 2473.Tn PCI 2474bus using information from the 2475.Tn BIOS . 2476See 2477.Xr pcibios 4 2478for details. 2479.It Cd options KSTACK_CHECK_DR0 2480Detect kernel stack overflow using DR0 register. 2481This option uses DR0 register exclusively so you can't use DR0 register for 2482other purpose (e.g., hardware breakpoint) if you turn this on. 2483.It Cd options MTRR 2484Include support for accessing MTRR registers from user-space. 2485See 2486.Xr i386_get_mtrr 2 . 2487.It Cd options BEEP_ONHALT 2488Make the system speaker emit several beeps when it is completely safe to 2489power down the computer after a 2490.Xr halt 8 2491command. 2492Requires 2493.Xr sysbeep 4 2494support. 2495.It Cd options BEEP_ONHALT_COUNT=times 2496Number of times to beep the speaker when 2497.Cd options BEEP_ONHALT 2498is enabled. 2499Defaults to 3. 2500.It Cd options BEEP_ONHALT_PITCH=hz 2501The tone frequency used when 2502.Cd options BEEP_ONHALT 2503option, in hertz. 2504Defaults to 1500. 2505.It Cd options BEEP_ONHALT_PERIOD=msecs 2506The duration of each beep when 2507.Cd options BEEP_ONHALT 2508is enabled, in milliseconds. 2509Defaults to 250. 2510.It Cd options MULTIBOOT 2511Makes the kernel Multiboot-compliant, allowing it to be booted through 2512a Multiboot-compliant boot manager such as GRUB. 2513See 2514.Xr multiboot 8 2515for more information. 2516.It Cd options SPLASHSCREEN 2517Display a splash screen during boot. 2518.It Cd options SPLASHSCREEN_PROGRESS 2519Display a progress bar at the splash screen during boot. 2520This option requires 2521.Em SPLASHSCREEN . 2522.El 2523.Ss isa-specific Options 2524Options specific to 2525.Xr isa 4 2526busses. 2527.Bl -ohang 2528.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2529Control the section of IO bus space used for PCMCIA bus space mapping. 2530Ideally the probed defaults are satisfactory, however in practice 2531that is not always the case. 2532See 2533.Xr pcmcia 4 2534for details. 2535.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2536Controls the allowable interrupts that may be used for 2537.Tn PCMCIA 2538devices. 2539This mask is a logical-or of power-of-2s of allowable interrupts: 2540.Bd -literal -offset 04n 2541.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2542 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2543 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2544 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2545 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2546.Ed 2547.It Cd options PCKBC_CNATTACH_SELFTEST 2548Perform a self test of the keyboard controller before attaching it as a 2549console. 2550This might be necessary on machines where we boot on cold iron, and 2551pckbc refuses to talk until we request a self test. 2552Currently only the netwinder port uses it. 2553.It Cd options PCKBD_CNATTACH_MAY_FAIL 2554If this option is set the PS/2 keyboard will not be used as the console 2555if it cannot be found during boot. 2556This allows other keyboards, like USB, to be the console keyboard. 2557.It Cd options PCKBD_LAYOUT=layout 2558Sets the default keyboard layout, see 2559.Xr pckbd 4 . 2560.El 2561.Ss m68k-specific Options 2562.Bl -ohang 2563.It Cd options FPU_EMULATE 2564Include support for MC68881/MC68882 emulator. 2565.It Cd options FPSP 2566Include support for 68040 floating point. 2567.It Cd options M68020,M68030,M68040,M68060 2568Include support for a specific 2569.Tn CPU , 2570at least one (the one you are using) should be specified. 2571.It Cd options M060SP 2572Include software support for 68060. 2573This provides emulation of unimplemented 2574integer instructions as well as emulation of unimplemented floating point 2575instructions and data types and software support for floating point traps. 2576.El 2577.Ss powerpc-specific Options (OEA Only) 2578.Bl -ohang 2579.It Cd options PMAP_MEMLIMIT=value 2580Limit the amount of memory seen by the kernel to 2581.Ar value 2582bytes. 2583.It Cd options PTEGCOUNT=value 2584Specify the size of the page table as 2585.Ar value 2586PTE groups. 2587Normally, one PTEG is allocated per physical page frame. 2588.El 2589.Ss sparc-specific Options 2590.Bl -ohang 2591.It Cd options AUDIO_DEBUG 2592Enable simple event debugging of the logging of the 2593.Xr audio 4 2594device. 2595.It Cd options BLINK 2596Enable blinking of LED. 2597Blink rate is full cycle every N seconds for 2598N \*[Lt] then current load average. 2599See 2600.Xr getloadavg 3 . 2601.\" .It Cd options COLORFONT_CACHE 2602.\" What does this do? 2603.It Cd options COUNT_SW_LEFTOVERS 2604Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2605sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2606variables accessible from 2607.Xr ddb 4 . 2608See 2609.Xr sw 4 . 2610.It Cd options DEBUG_ALIGN 2611Adds debugging messages calls when user-requested alignment fault 2612handling happens. 2613.It Cd options DEBUG_EMUL 2614Adds debugging messages calls for emulated floating point and 2615alignment fixing operations. 2616.It Cd options DEBUG_SVR4 2617Prints registers messages calls for emulated SVR4 getcontext and 2618setcontext operations. 2619See 2620.Em options COMPAT_SVR4 . 2621.It Cd options EXTREME_DEBUG 2622Adds debugging functions callable from 2623.Xr ddb 4 . 2624The debug_pagetables, test_region and print_fe_map 2625functions print information about page tables for the SUN4M 2626platforms only. 2627.It Cd options EXTREME_EXTREME_DEBUG 2628Adds extra info to 2629.Em options EXTREME_DEBUG . 2630.It Cd options FPU_CONTEXT 2631Make 2632.Em options COMPAT_SVR4 2633getcontext and setcontext include floating point registers. 2634.It Cd options MAGMA_DEBUG 2635Adds debugging messages to the 2636.Xr magma 4 2637device. 2638.It Cd options RASTERCONS_FULLSCREEN 2639Use the entire screen for the console. 2640.It Cd options RASTERCONS_SMALLFONT 2641Use the Fixed font on the console, instead of the normal font. 2642.It Cd options SUN4 2643Support sun4 class machines. 2644.It Cd options SUN4C 2645Support sun4c class machines. 2646.It Cd options SUN4M 2647Support sun4m class machines. 2648.It Cd options SUN4_MMU3L 2649.\" XXX ??? 2650Enable support for sun4 3-level MMU machines. 2651.It Cd options V9 2652Enable SPARC V9 assembler in 2653.Xr ddb 4 . 2654.El 2655.Ss sparc64-specific Options 2656.Bl -ohang 2657.It Cd options AUDIO_DEBUG 2658Enable simple event debugging of the logging of the 2659.Xr audio 4 2660device. 2661.It Cd options BLINK 2662Enable blinking of LED. 2663Blink rate is full cycle every N seconds for 2664N \*[Lt] then current load average. 2665See 2666.Xr getloadavg 3 . 2667.El 2668.Ss x68k-specific Options 2669.Bl -ohang 2670.It Cd options EXTENDED_MEMORY 2671Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2672.It Cd options JUPITER 2673Include support for Jupiter-X MPU accelerator 2674.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2675Use the built-in serial port as the system-console. 2676Speed is specified in bps, defaults to 9600. 2677.It Cd options ITE_KERNEL_ATTR=value 2678Set the kernel message attribute for ITE. 2679Value, an integer, is a logical or of the following values: 2680.Bl -tag -width 4n -compact -offset indent 2681.It 1 2682color inversed 2683.It 2 2684underlined 2685.It 4 2686bolded 2687.El 2688.El 2689.\" The following requests should be uncommented and used where appropriate. 2690.\" .Sh FILES 2691.\" .Sh EXAMPLES 2692.Sh SEE ALSO 2693.Xr config 1 , 2694.Xr gdb 1 , 2695.Xr ktrace 1 , 2696.Xr pmc 1 , 2697.Xr quota 1 , 2698.Xr vndcompress 1 , 2699.Xr gettimeofday 2 , 2700.Xr i386_get_mtrr 2 , 2701.Xr i386_iopl 2 , 2702.Xr msgctl 2 , 2703.Xr msgget 2 , 2704.Xr msgrcv 2 , 2705.Xr msgsnd 2 , 2706.Xr ntp_adjtime 2 , 2707.Xr ntp_gettime 2 , 2708.Xr reboot 2 , 2709.Xr semctl 2 , 2710.Xr semget 2 , 2711.Xr semop 2 , 2712.Xr shmat 2 , 2713.Xr shmctl 2 , 2714.Xr shmdt 2 , 2715.Xr shmget 2 , 2716.Xr sysctl 3 , 2717.Xr apm 4 , 2718.Xr ddb 4 , 2719.Xr inet 4 , 2720.Xr iso 4 , 2721.Xr md 4 , 2722.Xr pcibios 4 , 2723.Xr pcmcia 4 , 2724.Xr ppp 4 , 2725.Xr userconf 4 , 2726.Xr vnd 4 , 2727.Xr wscons 4 , 2728.Xr config 5 , 2729.Xr edquota 8 , 2730.Xr init 8 , 2731.Xr mdsetimage 8 , 2732.Xr mount_cd9660 8 , 2733.Xr mount_fdesc 8 , 2734.Xr mount_kernfs 8 , 2735.Xr mount_lfs 8 , 2736.Xr mount_mfs 8 , 2737.Xr mount_msdos 8 , 2738.Xr mount_nfs 8 , 2739.Xr mount_ntfs 8 , 2740.Xr mount_null 8 , 2741.Xr mount_portal 8 , 2742.Xr mount_procfs 8 , 2743.Xr mount_udf 8 , 2744.Xr mount_umap 8 , 2745.Xr mount_union 8 , 2746.Xr mrouted 8 , 2747.Xr newfs_lfs 8 , 2748.Xr ntpd 8 , 2749.Xr quotaon 8 , 2750.Xr rpc.rquotad 8 , 2751.Xr sysctl 8 , 2752.Xr in_getifa 9 2753.Sh HISTORY 2754The 2755.Nm 2756man page first appeared in 2757.Nx 1.3 . 2758.Sh BUGS 2759The 2760.Em EON 2761option should be a pseudo-device, and is also very fragile. 2762