1.\" $NetBSD: options.4,v 1.334 2006/09/23 11:16:50 wiz 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 September 20, 2006 34.Os 35.Dt OPTIONS 4 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 Xo 66.Qq Ar filename 67.Xc 68Conditionally includes another kernel configuration file whose name is 69.Ar filename , 70which may be double-quoted and may be an explicit path or relative to 71the kernel source directory. 72Failure to open the named file is ignored. 73.It Sy config Xo 74.Ar exec_name 75.No root on 76.Ar rootdev 77.Op type Ar fstype 78.Op dumps on Ar dumpdev 79.Xc 80Defines a configuration whose kernel executable is named 81.Ar exec_name , 82normally 83.Dq netbsd , 84with its root file system of type 85.Ar fstype 86on the device 87.Ar rootdev , 88and optionally specifying the location of kernel core dumps on the device 89.Ar dumpdev . 90.Ar dev 91or 92.Ar dumpdev 93and 94.Ar fstype 95may be specified as 96.Dq \&? , 97which is a wild card. 98The root 99.Ar fstype 100and 101.Ar dumpdev 102are optional and assumed to be wild carded if they are not specified. 103.It Ar device_instance Xo 104at 105.Ar attachment 106.Op Ar locators value Op ... 107.Op flags Ar value 108.Xc 109Define an instance of the device driver 110.Ar device_instance 111that attaches to the bus or device named 112.Ar attachment . 113An 114.Ar attachment 115may require additional information on where the device can be found, such 116as an address, channel, function, offset, and/or slot, referred to as 117.Ar locators , 118whose 119.Ar value 120often may be a wild card, 121.Dq \&? . 122Some device drivers have one or more 123.Ar flags 124that can be adjusted to affect the way they operate. 125.It Sy file-system Xo 126.Ar fs_name Op , Ar fs_name Op ... 127.Xc 128Include support for the file-system 129.Ar fs_name . 130.It Sy ident Xo 131.Qq Ar string 132.Xc 133Sets the kernel identification string to 134.Ar string . 135.It Sy include Xo 136.Qq Ar filename 137.Xc 138Functions the same as 139.Ar cinclude , 140except failure to open 141.Ar filename 142produces a fatal error. 143.It Sy options Xo 144.Ar option_name Op , Ar option_name=value Op ... 145.Xc 146Specifies (or sets) the option, or comma-separated list of options, 147.Ar option_name . 148Some options expect to be assigned a value, which may be an integer, 149a double-quoted word, a bare word, or an empty string 150.Pq Qq . 151Note that those are eventually handled by the C compiler, so the rules 152of that language apply. 153.Pp 154.Em Note : 155Options that are not defined by device definition files are passed to 156the compile process as 157.Fl D 158flags to the C compiler. 159.It Sy makeoptions Xo 160.Ar name=value 161.Xc 162Defines a 163.Xr make 1 164macro 165.Ar name 166with the value 167.Ar value 168in the kernel Makefile. 169.It Sy maxusers Xo 170.Ar integer 171.Xc 172Set the maxusers variable in the kernel. 173.It Sy no Xo 174.Ar keyword Ar name Op Ar arguments Op ... 175.Xc 176For the 177.Xr config 1 178.Ar keywords 179file-system, makeoptions, options, and pseudo-device, 180.Ar no 181removes the file-system, makeoption, options, or pseudo-device, 182.Ar name . 183This is useful when a kernel configuration file includes another which 184has undesired options. 185.Pp 186For example, a local configuration file that wanted the kitchen sink, but 187not COMPAT_09 or bridging, might be: 188.Bd -literal -offset indent 189include "arch/i386/conf/GENERIC" 190no options COMPAT_09 191no pseudo-device bridge 192.Ed 193.It Sy pseudo-device Xo 194.Ar name 195.Op Ar N 196.Xc 197Includes support for the pseudo-device 198.Ar name . 199Some pseudo-devices can have multiple or 200.Ar N 201instances. 202.El 203.Ss Compatibility Options 204.Bl -ohang 205.It Cd options COMPAT_09 206Enable binary compatibility with 207.Nx 0.9 . 208This enables support for 20916-bit user, group, and process IDs (following revisions support 21032-bit identifiers). 211It also allows the use of the deprecated 212.Xr getdomainname 3 , 213.Xr setdomainname 3 , 214and 215.Xr uname 3 216syscalls. 217This option also allows using numeric file system identifiers rather 218than strings. 219Post 220.Nx 0.9 221versions use string identifiers. 222.It Cd options COMPAT_10 223Enable binary compatibility with 224.Nx 1.0 . 225This option allows the use of the file system name of 226.Dq ufs 227as an alias for 228.Dq ffs . 229The name 230.Dq ffs 231should be used post 1.0 in 232.Pa /etc/fstab 233and other files. 234It also adds old syscalls for the 235.At V 236shared memory interface. 237This was changed post 1.0 to work on 64-bit architectures. 238This option also enables 239.Dq sgtty 240compatibility, without which programs using the old interface produce 241an 242.Dq inappropriate ioctl 243error, and 244.Pa /dev/io 245only works when this option is set in the kernel, 246see 247.Xr io 4 248on ports that support it. 249.It Cd options COMPAT_11 250Enable binary compatibility with 251.Nx 1.1 . 252This allows binaries running on the i386 port to gain direct access to 253the io ports by opening 254.Pa /dev/io 255read/write. 256This functionality was replaced by 257.Xr i386_iopl 2 258post 1.1. 259On the 260.Tn Atari 261port, the location of the disk label was moved after 1.1. 262When the 263.Em COMPAT_11 264option is set, the kernel will read (pre) 1.1 style disk labels as a 265last resort. 266When a disklabel is re-written, the old style label will be replaced 267with a post 1.1 style label. 268This also enables the 269.Em EXEC_ELF_NOTELESS 270option. 271.It Cd options COMPAT_12 272Enable binary compatibility with 273.Nx 1.2 . 274This allows the use of old syscalls for 275.Fn reboot 276and 277.Fn swapon . 278The syscall numbers were changed post 1.2 to add functionality to the 279.Xr reboot 2 280syscall, and the new 281.Xr swapctl 2 282interface was introduced. 283This also enables the 284.Em EXEC_ELF_NOTELESS 285option. 286.It Cd options COMPAT_13 287Enable binary compatibility with 288.Nx 1.3 . 289This allows the use of old syscalls for 290.Fn sigaltstack , 291and also enables the old 292.Xr swapctl 2 293command 294.Dv SWAP_STATS 295(now called 296.Dv SWAP_OSTATS ) , 297which does not include the 298.Fa se_path 299member of 300.Va struct swapent . 301.It Cd options COMPAT_14 302Enable binary compatibility with 303.Nx 1.4 . 304This allows some old 305.Xr ioctl 2 306on 307.Xr wscons 4 308to be performed, and allows the 309.Dv NFSSVC_BIOD 310mode of the 311.Xr nfssvc 2 312system call to be used for compatibility with the deprecated nfsiod program. 313.It Cd options COMPAT_16 314Enable binary compatibility with 315.Nx 1.6 . 316This allows the use of old signal trampoline code which has been deprecated 317with the addition of 318.Xr siginfo 2 . 319.It Cd options COMPAT_20 320Enable binary compatibility with 321.Nx 2.0 . 322This allows the use of old syscalls for 323.Fn statfs , 324.Fn fstatfs , 325.Fn getfsstat 326and 327.Fn fhstatfs , 328which have been deprecated with the addition of the 329.Xr statvfs 2 , 330.Xr fstatvfs 2 , 331.Xr getvfsstat 2 332and 333.Xr fhstatvfs 2 334system calls. 335.It Cd options COMPAT_30 336Enable binary compatibility with 337.Nx 3.0 . 338See 339.Xr compat_30 8 340for details about the changes made after the 341.Nx 3.0 342release. 343.It Cd options COMPAT_43 344Enables compatibility with 345.Bx 4.3 . 346This adds an old syscall for 347.Xr lseek 2 . 348It also adds the ioctls for 349.Dv TIOCGETP 350and 351.Dv TIOCSETP . 352The return values for 353.Xr getpid 2 , 354.Xr getgid 2 , 355and 356.Xr getuid 2 357syscalls are modified as well, to return the parent's PID and 358UID as well as the current process's. 359It also enables the deprecated 360.Dv NTTYDISC 361terminal line discipline. 362It also provides backwards compatibility with 363.Dq old 364SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 365binary compatibility with code written before the introduction of the 366sa_len field in sockaddrs. 367It also enables 368support for some older pre 369.Bx 4.4 370socket calls. 371.It Cd options COMPAT_BSDPTY 372This option is currenty on by default and enables the pty multiplexor 373.Xr ptm 4 374and 375.Xr ptmx 4 376to find and use ptys named 377.Pa /dev/ptyXX 378(master) and 379.Pa /dev/ttyXX 380(slave). 381Eventually this option will become optional as ptyfs based pseudo-ttys become 382the default, see 383.Xr mount_ptyfs 8 . 384.It Cd options COMPAT_SVR4 385On those architectures that support it, this enables binary 386compatibility with 387.At V.4 388applications built for the same architecture. 389This currently includes the i386, m68k, and sparc ports. 390.It Cd options COMPAT_LINUX 391On those architectures that support it, this enables binary 392compatibility with Linux ELF and 393.Xr a.out 5 394applications built for the same architecture. 395This currently includes the alpha, arm, i386, m68k, mips, powerpc and 396x86_64 ports. 397.It Cd options COMPAT_LINUX32 398On those 64 bit architectures that support it, this enables binary 399compatibility with 32 bit Linux binaries. 400For now this is limited to running i386 ELF Linux binaries on amd64. 401.It Cd options COMPAT_SUNOS 402On those architectures that support it, this enables binary 403compatibility with 404.Tn SunOS 4.1 405applications built for the same architecture. 406This currently includes the sparc, sparc64 and most or all m68k ports. 407Note that the sparc64 requires the 408.Em COMPAT_NETBSD32 409option for 64-bit kernels, in addition to this option. 410.It Cd options COMPAT_ULTRIX 411On those architectures that support it, this enables binary 412compatibility with 413.Tn ULTRIX 414applications built for the same architecture. 415This currently is limited to the pmax. 416The functionality of this option is unknown. 417.It Cd options COMPAT_DARWIN 418On those architectures that support it, this enables binary compatibility with 419.Tn Darwin 420applications built for the same architecture. 421This feature is highly experimental, it requires COMPAT_MACH and 422EXEC_MACHO and it is currently limited to i386 and powerpc ports of 423.Nx . 424.It Cd options COMPAT_FREEBSD 425On those architectures that support it, this enables binary 426compatibility with 427.Fx 428applications built for the same architecture. 429At the moment this is limited to the i386 port. 430.It Cd options COMPAT_HPUX 431On those architectures that support it, this enables binary 432compatibility with 433.Tn HP/UX 434applications built for the same architecture. 435This is limited to the hp300 port, and has some known bugs. 436A limited set of programs do work. 437.It Cd options COMPAT_IBCS2 438On those architectures that support it, this enables binary 439compatibility with iBCS2 or SVR3 applications built for the same architecture. 440This is currently limited to the i386 and vax ports. 441.It Cd options COMPAT_IRIX 442On those architectures that support it, this enables binary 443compatibility with IRIX o32 binaries built for the same architecture. 444This feature is experimental, and it is currently limited to 445the sgimips port. 446.It Cd options COMPAT_MACH 447On those architectures that support it, this enables the emulation of 448Mach kernel traps for binaries built for the same architecture. 449This feature is highly experimental and it is currently 450limited to the i386 and powerpc ports of 451.Nx . 452.It Cd options COMPAT_OSF1 453On those architectures that support it, this enables binary 454compatibility with 455.Tn Digital 456.Ux 457.Po 458formerly 459.Tn OSF/1 460.Pc 461applications built for the same architecture. 462This is currently limited to the alpha port. 463.It Cd options COMPAT_NOMID 464Enable compatibility with 465.Xr a.out 5 466executables that lack a machine ID. 467This includes 468.Nx 0.8 Ns 's 469ZMAGIC format, and 386BSD and BSDI's 470QMAGIC, NMAGIC, and OMAGIC 471.Xr a.out 5 472formats. 473.It Cd options COMPAT_NETBSD32 474On those architectures that support it, this enables binary 475compatibility with 32-bit applications built for the same architecture. 476This is currently limited to the amd64 and sparc64 ports, and only 477applicable for 64-bit kernels. 478.It Cd options COMPAT_SVR4_32 479On those architectures that support it, this enables binary 480compatibility with 32-bit SVR4 applications built for the same architecture. 481This is currently limited to the sparc64 port, and only applicable for 48264-bit kernels. 483.It Cd options COMPAT_AOUT_M68K 484On m68k architectures which have switched to ELF, 485this enables binary compatibility with 486.Nx Ns Tn /m68k 487.Xr a.out 5 488executables on 489.Nx Ns Tn /m68k 490ELF kernels. 491This handles alignment incompatibility of m68k ABI between 492a.out and ELF which causes the structure padding differences. 493Currently only some system calls which use 494.Va struct stat 495are adjusted and some binaries which use 496.Xr sysctl 3 497to retrieve network details would not work properly. 498.It Cd options EXEC_MACHO 499On those architectures that support it, this adds support for running 500Mach-O executables. 501This is currently limited to the i386 and powerpc ports of 502.Nx . 503.It Cd options EXEC_ELF_NOTELESS 504Run unidentified ELF binaries as 505.Nx 506binaries. 507This might be needed for very old 508.Nx 509ELF binaries on some archs. 510These old binaries didn't contain an appropriate 511.Li .note.netbsd.ident 512section, and thus can't be identified by the kernel as 513.Nx 514binaries otherwise. 515Beware - if this option is on, the kernel would run 516.Em any 517unknown ELF binaries as if they were 518.Nx 519binaries. 520.It Cd options P1003_1B_SEMAPHORE 521Includes kernel support for the standard C library 522.Pq libc 523functions that implement semaphores as specified in 524.St -p1003.1-96 . 525.El 526.Ss Debugging Options 527.Bl -ohang 528.It Cd options DDB 529Compiles in a kernel debugger for diagnosing kernel problems. 530See 531.Xr ddb 4 532for details. 533.Em NOTE : 534not available on all architectures. 535.It Cd options DDB_FROMCONSOLE=integer 536If set to non-zero, DDB may be entered by sending a break on a serial 537console or by a special key sequence on a graphics console. 538A value of "0" ignores console breaks or key sequences. 539If not explicitly specified, the default value is "1". 540Note that this sets the value of the 541.Em ddb.fromconsole 542.Xr sysctl 3 543variable which may be changed at run time -- see 544.Xr sysctl 8 545for details. 546.It Cd options DDB_HISTORY_SIZE=integer 547If this is non-zero, enable history editing in the kernel debugger 548and set the size of the history to this value. 549.It Cd options DDB_ONPANIC 550The default if not specified is 551.Dq 1 552- just enter into DDB. 553If set to 554.Dq 2 555the kernel will 556attempt to print out a stack trace before entering into DDB. 557If set to 558.Dq 0 559the kernel will attempt to print out a stack trace 560and reboot the system. 561If set to 562.Dq -1 563then neither a stack trace is printed or DDB entered - 564it is as if DDB were not compiled into the kernel. 565Note that this sets the value of the 566.Em ddb.onpanic 567.Xr sysctl 3 568variable which may be changed at run time -- see 569.Xr sysctl 8 570for details. 571.It Cd options DDB_COMMANDONENTER=string 572This option specify commands which will be executed on each entry to DDB. 573This sets the default value of the 574.Em ddb.commandonenter 575.Xr sysctl 3 576variable which may be changed at run time. 577.It Cd options DDB_BREAK_CHAR=integer 578This option overrides using break to enter the kernel debugger 579on the serial console. 580The value given is the ascii value to be used instead. 581This is currently only supported by the com driver. 582.It Cd options KGDB 583Compiles in a remote kernel debugger stub for diagnosing kernel problems 584using the 585.Dq remote target 586feature of gdb. 587See 588.Xr gdb 1 589for details. 590.Em NOTE : 591not available on all architectures. 592.It Cd options KGDB_DEV 593Device number 594.Po 595as a 596.Dv dev_t 597.Pc 598of kgdb device. 599.It Cd options KGDB_DEVADDR 600Memory address of kgdb device. 601.It Cd options KGDB_DEVMODE 602Permissions of kgdb device. 603.It Cd options KGDB_DEVNAME 604Device name of kgdb device. 605.It Cd options KGDB_DEVRATE 606Baud rate of kgdb device. 607.It Cd makeoptions DEBUG="-g" 608The 609.Fl g 610flag causes 611.Pa netbsd.gdb 612to be built in addition to 613.Pa netbsd . 614.Pa netbsd.gdb 615is useful for debugging kernel crash dumps with gdb. 616See 617.Xr gdb 1 618for details. 619This also turns on 620.Em options DEBUG 621(which see). 622.It Cd options DEBUG 623Turns on miscellaneous kernel debugging. 624Since options are turned into preprocessor defines (see above), 625.Em options DEBUG 626is equivalent to doing a 627.Em #define DEBUG 628throughout the kernel. 629Much of the kernel has 630.Em #ifdef DEBUG 631conditionalized debugging code. 632Note that many parts of the kernel (typically device drivers) include their own 633.Em #ifdef XXX_DEBUG 634conditionals instead. 635This option also turns on certain other options, 636which may decrease system performance. 637.It Cd options DIAGNOSTIC 638Adds code to the kernel that does internal consistency checks. 639This code will cause the kernel to panic if corruption of internal data 640structures is detected. 641These checks can decrease performance up to 15%. 642.It Cd options KSTACK_CHECK_MAGIC 643Check kernel stack usage and panic if stack overflow is detected. 644This check is performance sensitive because it scans stack on each context 645switch. 646.It Cd options KTRACE 647Add hooks for the system call tracing facility, which allows users to 648watch the system call invocation behavior of processes. 649See 650.Xr ktrace 1 651for details. 652.It Cd options MSGBUFSIZE=integer 653This option sets the size of the kernel message buffer. 654This buffer holds the kernel output of 655.Fn printf 656when not (yet) read by 657.Xr syslogd 8 . 658This is particularly useful when the system has crashed and you wish to lookup 659the kernel output from just before the crash. 660Also, since the autoconfig output becomes more and more verbose, 661it sometimes happens that the message buffer overflows before 662.Xr syslogd 8 663was able to read it. 664Note that not all systems are capable of obtaining a variable sized message 665buffer. 666There are also some systems on which memory contents are not preserved 667across reboots. 668.It Cd options MALLOCLOG 669Enables an event log for 670.Xr malloc 9 . 671Useful for tracking down 672.Dq Data modified on freelist 673and 674.Dq multiple free 675problems. 676.It Cd options MALLOCLOGSIZE=integer 677Defines the number of entries in the malloc log. 678Default is 100000 entries. 679.It Cd options SYSTRACE 680Add hooks for the system call policy facility. 681See 682.Xr systrace 1 683for details. 684.It Cd options UVMHIST 685Enables the UVM history logs, which create in-memory traces of 686various UVM activities. 687These logs can be displayed be calling 688.Fn uvmhist_dump 689or 690.Fn uvm_hist 691with appropriate arguments from DDB. 692See the kernel source file sys/uvm/uvm_stat.c for details. 693.It Cd options UVMHIST_PRINT 694Prints the UVM history logs on the system console as entries are added. 695Note that the output is 696.Em extremely 697voluminous, so this option is really only useful for debugging 698the very earliest parts of kernel initialization. 699.El 700.Ss File Systems 701.Bl -ohang 702.It Cd file-system FFS 703Includes code implementing the Berkeley Fast File System 704.Em ( FFS ) . 705Most machines need this if they are not running diskless. 706.It Cd file-system EXT2FS 707Includes code implementing the Second Extended File System 708.Em ( EXT2FS ) , 709revision 0 and revision 1 with the 710.Em filetype 711and 712.Em sparse_super 713options. 714This is the most commonly used file system on the Linux operating system, 715and is provided here for compatibility. 716Some of the specific features of 717.Em EXT2FS 718like the "behavior on errors" are not implemented. 719This file system can't be used with UID or GID greater than 65535. 720See 721.Xr mount_ext2fs 8 722for details. 723.It Cd file-system LFS 724.Bq Em EXPERIMENTAL 725Include the Log-structured File System 726.Em ( LFS ) . 727See 728.Xr mount_lfs 8 729and 730.Xr newfs_lfs 8 731for details. 732.It Cd file-system MFS 733Include the Memory File System 734.Em ( MFS ) . 735This file system stores files in swappable memory, and produces 736notable performance improvements when it is used as the file store 737for 738.Pa /tmp 739and similar file systems. 740See 741.Xr mount_mfs 8 742for details. 743.It Cd file-system NFS 744Include the client side of the Network File System 745.Pq Tn NFS 746remote file sharing protocol. 747Although the bulk of the code implementing 748.Tn NFS 749is kernel based, several user level daemons are needed for it to work. 750See 751.Xr mount_nfs 8 752for details. 753.It Cd file-system CD9660 754Includes code for the 755.Tn ISO 7569660 + Rock Ridge file system, which is the standard file system on many 757.Tn CD-ROM 758discs. 759Useful primarily if you have a 760.Tn CD-ROM 761drive. 762See 763.Xr mount_cd9660 8 764for details. 765.It Cd file-system MSDOSFS 766Includes the 767.Tn MS-DOS 768FAT file system, which is reportedly still used 769by unfortunate people who have not heard about 770.Nx . 771Also implements the 772.Tn Windows 95 773extensions to the same, which permit the use of longer, mixed case 774file names. 775See 776.Xr mount_msdos 8 777and 778.Xr fsck_msdos 8 779for details. 780.It Cd file-system NTFS 781.Bq Em EXPERIMENTAL 782Includes code for the 783.Tn Microsoft Windows NT 784file system. 785See 786.Xr mount_ntfs 8 787for details. 788.It Cd file-system FDESC 789Includes code for a file system, conventionally mounted on 790.Pa /dev/fd , 791which permits access to the per-process file descriptor space via 792special files in the file system. 793See 794.Xr mount_fdesc 8 795for details. 796Note that this facility is redundant, and thus unneeded on most 797.Nx 798systems, since the 799.Xr fd 4 800pseudo-device driver already provides identical functionality. 801On most 802.Nx 803systems, instances of 804.Xr fd 4 805are mknoded under 806.Pa /dev/fd/ 807and on 808.Pa /dev/stdin , 809.Pa /dev/stdout , 810and 811.Pa /dev/stderr . 812.It Cd file-system KERNFS 813Includes code which permits the mounting of a special file system 814(normally mounted on 815.Pa /kern ) 816in which files representing various kernel variables and parameters 817may be found. 818See 819.Xr mount_kernfs 8 820for details. 821.It Cd file-system NULLFS 822Includes code for a loopback file system. 823This permits portions of the file hierarchy to be re-mounted in other places. 824The code really exists to provide an example of a stackable file system layer. 825See 826.Xr mount_null 8 827for details. 828.It Cd file-system OVERLAY 829Includes code for a file system filter. 830This permits the overlay file system to intercept all access to an underlying 831file system. 832This file system is intended to serve as an example of a stacking file 833system which has a need to interpose itself between an underlying file 834system and all other access. 835See 836.Xr mount_overlay 8 837for details. 838.It Cd file-system PORTAL 839.Bq Em EXPERIMENTAL 840Includes the portal file system. 841This permits interesting tricks like opening 842.Tn TCP 843sockets by opening files in the file system. 844The portal file system is conventionally mounted on 845.Pa /p 846and is partially implemented by a special daemon. 847See 848.Xr mount_portal 8 849for details. 850.It Cd file-system PROCFS 851Includes code for a special file system (conventionally mounted on 852.Pa /proc ) 853in which the process space becomes visible in the file system. 854Among 855other things, the memory spaces of processes running on the system are 856visible as files, and signals may be sent to processes by writing to 857.Pa ctl 858files in the procfs namespace. 859See 860.Xr mount_procfs 8 861for details. 862.It Cd file-system UDF 863.Bq Em EXPERIMENTAL 864Includes code for the UDF file system commonly found on CD and DVD 865media but also more and more on USB sticks. 866Useful primarily if you have a CD or a DVD drive, be it a read-only 867or a rewritable device. 868Currently only supports read-access. 869See 870.Xr mount_udf 8 871for details. 872.It Cd file-system UMAPFS 873Includes a loopback file system in which user and group IDs may be 874remapped -- this can be useful when mounting alien file systems with 875different UIDs and GIDs than the local system. 876See 877.Xr mount_umap 8 878for details. 879.It Cd file-system UNION 880.Bq Em EXPERIMENTAL 881Includes code for the union file system, which permits directories to 882be mounted on top of each other in such a way that both file systems 883remain visible -- this permits tricks like allowing writing (and the 884deleting of files) on a read-only file system like a 885.Tn CD-ROM 886by mounting a local writable file system on top of the read-only file system. 887See 888.Xr mount_union 8 889for details. 890.It Cd file-system CODA 891.Bq Em EXPERIMENTAL 892Includes code for the Coda file system. 893Coda is a distributed file system like NFS and AFS. 894It is freely available, like NFS, but it functions much like AFS in being a 895.Dq stateful 896file system. 897Both Coda and AFS cache files on your local machine to improve performance. 898Then Coda goes a step further than AFS by letting you access the cached 899files when there is no available network, viz. disconnected laptops and 900network outages. 901In Coda, both the client and server are outside the kernel which makes 902them easier to experiment with. 903Coda is available for several UNIX and non-UNIX platforms. 904See http://www.coda.cs.cmu.edu for more details. 905.Em NOTE : 906You also need to enable the pseudo-device, vcoda, for the Coda 907file system to work. 908.It Cd file-system SMBFS 909.Bq Em EXPERIMENTAL 910Includes code for the SMB/CIFS file system. 911See 912.Xr mount_smbfs 8 913for details. 914.Em NOTE : 915You also need to enable the pseudo-device, nsmb, for the SMB 916file system to work. 917.It Cd file-system PTYFS 918.Bq Em EXPERIMENTAL 919Includes code for a special file system (normally mounted on 920.Pa /dev/pts ) 921in which pseudo-terminal slave devices become visible in the file system. 922See 923.Xr mount_ptyfs 8 924for details. 925.It Cd file-system TMPFS 926.Bq Em EXPERIMENTAL 927Includes code for the efficient memory file system, normally used over 928.Pa /tmp . 929See 930.Xr mount_tmpfs 8 931for details. 932.El 933.Ss File System Options 934.Bl -ohang 935.It Cd options MAGICLINKS 936Enables the expansion of special strings 937.Po 938beginning with 939.Dq @ 940.Pc 941when traversing symbolic links. 942See 943.Xr symlink 7 944for a list of supported strings. 945Note that this option only controls the enabling of this feature 946by the kernel at boot-up. 947This feature can still be manipulated with the 948.Xr sysctl 8 949command regardless of the setting of this option. 950.It Cd options NFSSERVER 951Include the server side of the 952.Em NFS 953(Network File System) remote file sharing protocol. 954Although the bulk of the code implementing 955.Em NFS 956is kernel based, several user level daemons are needed for it to 957work. 958See 959.Xr mountd 8 960and 961.Xr nfsd 8 962for details. 963.It Cd options QUOTA 964Enables kernel support for file system quotas. 965See 966.Xr quotaon 8 , 967.Xr edquota 8 , 968and 969.Xr quota 1 970for details. 971Note that quotas only work on 972.Dq ffs 973file systems, although 974.Xr rpc.rquotad 8 975permits them to be accessed over 976.Em NFS . 977.It Cd options FFS_EI 978Enable ``Endian-Independent'' FFS support. 979This allows a system to mount an FFS file system created for another 980architecture, at a small performance cost for all FFS file systems. 981See also 982.Xr newfs 8 , 983.Xr fsck_ffs 8 , 984.Xr dumpfs 8 985for file system byte order status and manipulation. 986.It Cd options FFS_NO_SNAPSHOT 987Disable the 988.Dq file system snapshot 989support in FFS file systems. 990Maybe useful for install media kernels, small memory systems and 991embedded systems which don't require the snapshot support. 992.It Cd options NVNODE=integer 993This option sets the size of the cache used by the name-to-inode translation 994routines, (a.k.a. the 995.Fn namei 996cache, though called by many other names in the kernel source). 997By default, this cache has 998.Dv NPROC 999(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 1000A reasonable way to derive a value of 1001.Dv NVNODE , 1002should you notice a large number of namei cache misses with a tool such as 1003.Xr systat 1 , 1004is to examine your system's current computed value with 1005.Xr sysctl 8 , 1006(which calls this parameter "kern.maxvnodes") and to increase this value 1007until either the namei cache hit rate improves or it is determined that 1008your system does not benefit substantially from an increase in the size of 1009the namei cache. 1010.It Cd options NAMECACHE_ENTER_REVERSE 1011Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1012as well as a normal one. 1013Normally, this is already done for directory vnodes, to speed up the getcwd 1014operation. 1015This option will cause longer hash chains in the reverse cache, and thus 1016slow down getcwd somewhat. 1017However, it does make vnode -\*[Gt] path translations possible in some cases. 1018For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1019required. 1020.It Cd options EXT2FS_SYSTEM_FLAGS 1021This option changes the behavior of the APPEND and IMMUTABLE flags 1022for a file on an 1023.Em EXT2FS 1024file system. 1025Without this option, the superuser or owner of the file can 1026set and clear them. 1027With this option, only the superuser can set them, and 1028they can't be cleared if the securelevel is greater than 0. 1029See also 1030.Xr chflags 1 . 1031.It Cd options NFS_BOOT_BOOTP 1032Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1033information if NFS is used to mount the root file system. 1034See 1035.Xr diskless 8 1036for details. 1037.It Cd options NFS_BOOT_DHCP 1038Same as 1039.Dq NFS_BOOT_BOOTP , 1040but use the DHCP extensions to the 1041BOOTP protocol (RFC 1541). 1042.It Cd options NFS_BOOT_BOOTP_REQFILE 1043Specifies the string sent in the bp_file field of the BOOTP / DHCP 1044request packet. 1045.It Cd options NFS_BOOT_BOOTPARAM 1046Enable use of the BOOTPARAM protocol, consisting of RARP and 1047BOOTPARAM RPC, to get configuration information if NFS 1048is used to mount the root file system. 1049See 1050.Xr diskless 8 1051for details. 1052.It Cd options NFS_BOOT_RWSIZE=value 1053Set the initial NFS read and write sizes for diskless-boot requests. 1054The normal default is 8Kbytes. 1055This option provides a way to lower the value (e.g., to 1024 bytes) 1056as a workaround for buggy network interface cards or boot PROMs. 1057Once booted, the read and write request sizes can be increased by 1058remounting the file system. 1059See 1060.Xr mount_nfs 8 1061for details. 1062.It Cd options NFS_V2_ONLY 1063Reduce the size of the NFS client code by omitting code that's only required 1064for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1065servers. 1066.It Cd options SOFTDEP 1067Enable kernel support for soft-dependencies in FFS filesystems. 1068Softdep improves write performance by aggregating and properly 1069ordering disk metadata writes, achieving near-asynchronous write 1070performance while maintaining the filesystem consistency of 1071synchronous writes. 1072Soft-dependencies are enabled on a per-mount basis. 1073See 1074.Xr mount 8 1075for details. 1076.It Cd options UFS_DIRHASH 1077Increase lookup performance by maintaining in-core hash tables 1078for large directories. 1079.El 1080.Ss Buffer queue strategy options 1081The following options enable alternative buffer queue strategies. 1082.Bl -ohang 1083.It Cd options BUFQ_READPRIO 1084Enable experimental buffer queue strategy for disk I/O. 1085In the default strategy, outstanding disk requests are ordered by 1086sector number and sent to the disk, regardless of whether the 1087operation is a read or write; this option gives priority to issuing 1088read requests over write requests. 1089Although requests may therefore be issued out of sector-order, causing 1090more seeks and thus lower overall throughput, interactive system 1091responsiveness under heavy disk I/O load may be improved, as processes 1092blocking on disk reads are serviced sooner (file writes typically 1093don't cause applications to block). 1094The performance effect varies greatly depending on the hardware, drive 1095firmware, filesystem configuration, workload, and desired performance 1096trade-off. 1097Systems using drive write-cache (most modern IDE disks, by default) 1098are unlikely to benefit and may well suffer; such disks acknowledge 1099writes very quickly, and optimise them internally according to 1100physical layout. 1101Giving these disks as many requests to work with as possible (the 1102standard strategy) will typically produce the best results, especially 1103if the drive has a large cache; the drive will silently complete 1104writes from cache as it seeks for reads. 1105Disks that support a large number of concurrent tagged requests (SCSI 1106disks and many hardware RAID controllers) expose this internal 1107scheduling with tagged responses, and don't block for reads; such 1108disks may not see a noticable difference with either strategy. 1109However, if IDE disks are run with write-cache disabled for safety, 1110writes are not acknowledged until actually completed, and only one 1111request can be outstanding; a large number of small writes in one 1112locality can keep the disk busy, starving reads elsewhere on the disk. 1113Such systems are likely to see the most benefit from this option. 1114Finally, the performance interaction of this option with ffs soft 1115dependencies can be subtle, as that mechanism can drastically alter 1116the workload for filesystem metadata writes. 1117.It Cd options BUFQ_PRIOCSCAN 1118Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1119.It Cd options NEW_BUFQ_STRATEGY 1120Synonym of 1121.Em BUFQ_READPRIO . 1122.El 1123.Ss Miscellaneous Options 1124.Bl -ohang 1125.It Cd options LKM 1126Enable loadable kernel modules. 1127See 1128.Xr lkm 4 1129for details. 1130.Em NOTE : 1131not available on all architectures. 1132.It Cd options MEMORY_DISK_DYNAMIC 1133This option makes the 1134.Xr md 4 1135.Tn RAM 1136disk size dynamically sized. 1137It is incompatible with 1138.Xr mdsetimage 8 . 1139.It Cd options MEMORY_DISK_HOOKS 1140This option allows for some machine dependent functions to be called when 1141the 1142.Xr md 4 1143.Tn RAM 1144disk driver is configured. 1145This can result in automatically loading a 1146.Tn RAM 1147disk from floppy on open (among other things). 1148.It Cd options MEMORY_DISK_IS_ROOT 1149Forces the 1150.Xr md 4 1151.Tn RAM 1152disk to be the root device. 1153This can only be overridden when 1154the kernel is booted in the 'ask-for-root' mode. 1155.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1156Allocates the given number of 512 byte blocks as memory for the 1157.Xr md 4 1158.Tn RAM 1159disk, to be populated with 1160.Xr mdsetimage 8 . 1161.It Cd options MEMORY_DISK_SERVER=0 1162Do not include the interface to a userland memory disk server process. 1163Per default, this option is set to 1, including the support code. 1164Useful for install media kernels. 1165.It Cd options VND_COMPRESSION 1166Enables the 1167.Xr vnd 4 1168driver to also handle compressed images. 1169See 1170.Xr vndcompress 1 , 1171.Xr vnd 4 1172and 1173.Xr vnconfig 8 1174for more information. 1175.It Cd options MALLOC_NOINLINE 1176Time critical fixed size memory allocation is performed with 1177.Fn MALLOC 1178and 1179.Fn FREE . 1180Normally these expand to inline code, but with 1181.Em MALLOC_NOINLINE 1182these call the normal 1183.Fn malloc 1184and 1185.Fn free 1186functions. 1187Useful for install media kernels, small memory systems and embedded systems. 1188.It Cd options HZ=integer 1189On ports that support it, set the system clock frequency (see 1190.Xr hz 9 ) 1191to the supplied value. 1192Handle with care. 1193.It Cd options NTP 1194Turns on in-kernel precision timekeeping support used by software 1195implementing 1196.Em NTP 1197(Network Time Protocol, RFC 1305). 1198The 1199.Em NTP 1200option adds an in-kernel Phase-Locked Loop (PLL) for normal 1201.Em NTP 1202operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1203operation. 1204.Xr ntpd 8 1205will employ a user-level PLL when kernel support is unavailable, 1206but the in-kernel version has lower latency and more precision, and 1207so typically keeps much better time. 1208The interface to the kernel 1209.Em NTP 1210support is provided by the 1211.Xr ntp_adjtime 2 1212and 1213.Xr ntp_gettime 2 1214system calls, which are intended for use by 1215.Xr ntpd 8 1216and are enabled by the option. 1217On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1218is not an integer, the 1219.Em NTP 1220option also enables extended-precision arithmetic to keep track of 1221fractional clock ticks at NTP time-format precision. 1222.It Cd options PPS_SYNC 1223This option enables a kernel serial line discipline for receiving time 1224phase signals from an external reference clock such as a radio clock. 1225(The 1226.Em NTP 1227option (which see) must be on if the 1228.Em PPS_SYNC 1229option is used.) 1230Some reference clocks generate a Pulse Per Second (PPS) signal in 1231phase with their time source. 1232The 1233.Em PPS 1234line discipline receives this signal on either the data leads 1235or the DCD control lead of a serial port. 1236.Em NTP 1237uses the PPS signal to discipline the local clock oscillator to a high 1238degree of precision (typically less than 50 microseconds in time and 12390.1 ppm in accuracy). 1240.Em PPS 1241can also generate a serial output pulse when the system receives a PPS 1242interrupt. 1243This can be used to measure the system interrupt latency and thus calibrate 1244.Em NTP 1245to account for it. 1246Using 1247.Em PPS 1248usually requires a 1249gadget box 1250to convert from TTL to RS-232 signal levels. 1251The gadget box and PPS are described in more detail in the HTML documentation 1252for 1253.Xr ntpd 8 1254in 1255.Pa /usr/share/doc/html/ntp . 1256.It Cd options NO_TSC_TIME 1257Don't use TSC microtime, even if available (i386 only). 1258Improves time behavior under VMware. 1259.It Cd options SETUIDSCRIPTS 1260Allows scripts with the setuid bit set to execute as the effective 1261user rather than the real user, just like binary executables. 1262.Pp 1263.Em NOTE : 1264Using this option will also enable 1265.Em options FDSCRIPTS 1266.It Cd options FDSCRIPTS 1267Allows execution of scripts with the execute bit set, but not the 1268read bit, by opening the file and passing the file descriptor to 1269the shell, rather than the filename. 1270.Pp 1271.Em NOTE : 1272Execute only (non-readable) scripts will have 1273.Va argv[0] 1274set to 1275.Pa /dev/fd/* . 1276What this option allows as far as security is 1277concerned, is the ability to safely ensure that the correct script 1278is run by the interpreter, as it is passed as an already open file. 1279.It Cd options PUCCN 1280Enables treating serial ports found on PCI boards 1281.Xr puc 4 1282as potential console devices. 1283The method for choosing such a console device is port dependent. 1284.It Cd options RTC_OFFSET=integer 1285The kernel (and typically the hardware battery backed-up clock on 1286those machines that have one) keeps time in 1287.Em UTC 1288(Universal Coordinated Time, once known as 1289.Em GMT , 1290or Greenwich Mean Time) 1291and not in the time of the local time zone. 1292The 1293.Em RTC_OFFSET 1294option is used on some ports (such as the i386) to tell the kernel 1295that the hardware clock is offset from 1296.Em UTC 1297by the specified number of minutes. 1298This is typically used when a machine boots several operating 1299systems and one of them wants the hardware clock to run in the 1300local time zone and not in 1301.Em UTC , 1302e.g. 1303.Em RTC_OFFSET=300 1304means 1305the hardware clock is set to US Eastern Time (300 minutes behind 1306.Em UTC ) , 1307and not 1308.Em UTC . 1309(Note: 1310.Em RTC_OFFSET 1311is used to initialize a kernel variable named 1312.Va rtc_offset 1313which is the source actually used to determine the clock offset, and 1314which may be accessed via the kern.rtc_offset sysctl variable. 1315See 1316.Xr sysctl 8 1317and 1318.Xr sysctl 3 1319for details. 1320Since the kernel clock is initialized from the hardware clock very 1321early in the boot process, it is not possible to meaningfully change 1322.Va rtc_offset 1323in system initialization scripts. 1324Changing this value currently may only be done at kernel compile 1325time or by patching the kernel and rebooting). 1326.Pp 1327.Em NOTE : 1328Unfortunately, in many cases where the hardware clock 1329is kept in local time, it is adjusted for Daylight Savings 1330Time; this means that attempting to use 1331.Em RTC_OFFSET 1332to let 1333.Nx 1334coexist with such an operating system, like Windows, 1335would necessitate changing 1336.Em RTC_OFFSET 1337twice a year. 1338As such, this solution is imperfect. 1339.It Cd options KMEMSTATS 1340The kernel memory allocator, 1341.Xr malloc 9 , 1342will keep statistics on its performance if this option is enabled. 1343Unfortunately, this option therefore essentially disables the 1344.Fn MALLOC 1345and 1346.Fn FREE 1347forms of the memory allocator, which are used to enhance the performance 1348of certain critical sections of code in the kernel. 1349This option therefore can lead to a significant decrease in the 1350performance of certain code in the kernel if enabled. 1351Examples of such code include the 1352.Fn namei 1353routine, the 1354.Xr ccd 4 1355driver, 1356and much of the networking code. 1357.It Cd options MAXUPRC=integer 1358Sets the soft 1359.Dv RLIMIT_NPROC 1360resource limit, which specifies the maximum number of simultaneous 1361processes a user is permitted to run, for process 0; 1362this value is inherited by its child processes. 1363It defaults to 1364.Em CHILD_MAX , 1365which is currently defined to be 160. 1366Setting 1367.Em MAXUPRC 1368to a value less than 1369.Em CHILD_MAX 1370is not permitted, as this would result in a violation of the semantics of 1371.St -p1003.1-90 . 1372.It Cd options NOFILE=integer 1373Sets the soft 1374.Dv RLIMIT_NOFILE 1375resource limit, which specifies the maximum number of open 1376file descriptors for each process; 1377this value is inherited by its child processes. 1378It defaults to 1379.Em OPEN_MAX , 1380which is currently defined to be 64. 1381.It Cd options MAXFILES=integer 1382Sets the default value of the 1383.Em kern.maxfiles 1384sysctl variable, which indicates the maximum number of files that may 1385be open in the system. 1386.It Cd options DEFCORENAME=string 1387Sets the default value of the 1388.Em kern.defcorename 1389sysctl variable, otherwise it is set to 1390.Nm %n.core . 1391See 1392.Xr sysctl 8 1393and 1394.Xr sysctl 3 1395for details. 1396.It Cd options RASOPS_CLIPPING 1397Enables clipping within the 1398.Nm rasops 1399raster-console output system. 1400.Em NOTE : 1401only available on architectures that use 1402.Nm rasops 1403for console output. 1404.It Cd options RASOPS_SMALL 1405Removes optimized character writing code from the 1406.Nm rasops 1407raster-console output system. 1408.Em NOTE : 1409only available on architectures that use 1410.Nm rasops 1411for console output. 1412.It Cd options INCLUDE_CONFIG_FILE 1413Embeds the kernel config file used to define the kernel in the kernel 1414binary itself. 1415The embedded data also includes any files directly included by the config 1416file itself, e.g. 1417.Pa GENERIC.local 1418or 1419.Pa std.$MACHINE . 1420The embedded config file can be extracted from the resulting kernel with 1421.Xr config 1 1422.Fl x , 1423or by the following command: 1424.Bd -literal -offset indent 1425strings netbsd | sed -n 's/^_CFG_//p' | unvis 1426.Ed 1427.It Cd options INCLUDE_JUST_CONFIG 1428Similar to the above option, but includes just the actual config file, 1429not any included files. 1430.It Cd options PIPE_SOCKETPAIR 1431Use slower, but smaller socketpair(2)-based pipe implementation instead 1432of default faster, but bigger one. 1433Primarily useful for installation kernels. 1434.It Cd options USERCONF 1435Compiles in the in-kernel device configuration manager. 1436See 1437.Xr userconf 4 1438for details. 1439.It Cd options PERFCTRS 1440Compiles in kernel support for CPU performance-monitoring counters. 1441See 1442.Xr pmc 1 1443for details. 1444.Em NOTE : 1445not available on all architectures. 1446.It Cd options XSERVER 1447Compiles in kernel support for 1448.Tn X11 1449on architectures that still use (or can use) the legacy 1450.Em pccons 1451console drivers rather than 1452.Xr wscons 4 . 1453These include bebox, i386, shark. 1454.It Cd options XSERVER_DDB 1455A supplement to XSERVER that adds support for entering 1456.Xr ddb 4 1457while in 1458.Tn X11 . 1459.It Cd options FILEASSOC 1460Support for 1461.Xr fileassoc 9 . 1462.It Cd options FILEASSOC_NHOOKS=integer 1463Number of storage slots per file for 1464.Xr fileassoc 9 . 1465Default is 4. 1466.El 1467.Ss Networking Options 1468.Bl -ohang 1469.It Cd options GATEWAY 1470Enables 1471.Em IPFORWARDING 1472(which see) 1473and (on most ports) increases the size of 1474.Em NMBCLUSTERS 1475(which see). 1476In general, 1477.Em GATEWAY 1478is used to indicate that a system should act as a router, and 1479.Em IPFORWARDING 1480is not invoked directly. 1481(Note that 1482.Em GATEWAY 1483has no impact on protocols other than 1484.Tn IP , 1485such as 1486.Tn CLNP 1487or 1488.Tn XNS ) . 1489.Em GATEWAY 1490option also compiles IPv4 fast forwarding code into the kernel. 1491.It Cd options ICMPPRINTFS 1492The 1493.Em ICMPPRINTFS 1494option will enable debugging information to be printed about 1495the 1496.Xr icmp 4 1497protocol. 1498.It Cd options IPFORWARDING=value 1499If 1500.Em value 1501is 1 this enables IP routing behavior. 1502If 1503.Em value 1504is 0 (the default), it disables it. 1505The 1506.Em GATEWAY 1507option sets this to 1 automatically. 1508With this option enabled, the machine will forward IP datagrams destined 1509for other machines between its interfaces. 1510Note that even without this option, the kernel will 1511still forward some packets (such as source routed packets) -- removing 1512.Em GATEWAY 1513and 1514.Em IPFORWARDING 1515is insufficient to stop all routing through a bastion host on a 1516firewall -- source routing is controlled independently. 1517To turn off source routing, use 1518.Em options IPFORWSRCRT=0 1519(which see). 1520Note that IP forwarding may be turned on and off independently of the 1521setting of the 1522.Em IPFORWARDING 1523option through the use of the 1524.Em net.inet.ip.forwarding 1525sysctl variable. 1526If 1527.Em net.inet.ip.forwarding 1528is 1, IP forwarding is on. 1529See 1530.Xr sysctl 8 1531and 1532.Xr sysctl 3 1533for details. 1534.It Cd options IPFORWSRCRT=value 1535If 1536.Em value 1537is set to zero, source routing of IP datagrams is turned off. 1538If 1539.Em value 1540is set to one (the default) or the option is absent, source routed IP 1541datagrams are forwarded by the machine. 1542Note that source routing of IP packets may be turned on and off 1543independently of the setting of the 1544.Em IPFORWSRCRT 1545option through the use of the 1546.Em net.inet.ip.forwsrcrt 1547sysctl variable. 1548If 1549.Em net.inet.ip.forwsrcrt 1550is 1, forwarding of source routed IP datagrams is on. 1551See 1552.Xr sysctl 8 1553and 1554.Xr sysctl 3 1555for details. 1556.It Cd options IFA_STATS 1557Tells the kernel to maintain per-address statistics on bytes sent 1558and received over (currently) internet and appletalk addresses. 1559.\"This can be a fairly expensive operation, so you probably want to 1560.\"keep this disabled. 1561The option is not recommended as it degrades system stability. 1562.It Cd options IFQ_MAXLEN=value 1563Increases the allowed size of the network interface packet queues. 1564The default queue size is 50 packets, and you do not normally need 1565to increase it. 1566.It Cd options MROUTING 1567Includes support for IP multicast routers. 1568You certainly want 1569.Em INET 1570with this. 1571Multicast routing is controlled by the 1572.Xr mrouted 8 1573daemon. 1574See also option 1575.Cd PIM . 1576.It Cd options PIM 1577Includes support for Protocol Independent Multicast (PIM) routing. 1578You need 1579.Em MROUTING 1580and 1581.Em INET 1582with this. 1583Software using this can be found e.g. in 1584.Pa pkgsrc/net/xorp . 1585.It Cd options INET 1586Includes support for the 1587.Tn TCP/IP 1588protocol stack. 1589You almost certainly want this. 1590See 1591.Xr inet 4 1592for details. 1593.It Cd options INET6 1594Includes support for the 1595.Tn IPv6 1596protocol stack. 1597See 1598.Xr inet6 4 1599for details. 1600Unlike 1601.Em INET , 1602.Em INET6 1603enables multicast routing code as well. 1604This option requires 1605.Em INET 1606at this moment, but it should not. 1607.It Cd options ND6_DEBUG 1608The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1609for debugging IPv6 neighbor discovery protocol handling. 1610See 1611.Xr sysctl 3 1612for details. 1613.It Cd options IPSEC 1614Includes support for the 1615.Tn IPsec 1616protocol. 1617See 1618.Xr ipsec 4 1619for details. 1620.It Cd options IPSEC_DEBUG 1621Enables debugging code in 1622.Tn IPsec 1623stack. 1624See 1625.Xr ipsec 4 1626for details. 1627.It Cd options IPSEC_ESP 1628Includes support for 1629.Tn IPsec 1630.Tn ESP 1631protocol. 1632See 1633.Xr ipsec 4 1634for details. 1635.It Cd options IPSEC_NAT_T 1636Includes support for 1637.Tn IPsec 1638Network Address Translator traversal (NAT-T), as described in RFCs 3947 1639and 3948. 1640This feature might be patent-encumbered in some countries. 1641.It Cd options ALTQ 1642Enabled ALTQ (Alternate Queueing). 1643For simple rate-limiting, use 1644.Xr tbrconfig 8 1645to set up the interface transmission rate. 1646To use queueing disciplines, their appropriate kernel options should also 1647be defined (documented below). 1648Queueing disciplines are managed by 1649.Xr altqd 8 . 1650See 1651.Xr altq 9 1652for details. 1653.It Cd options ALTQ_HFSC 1654Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1655module. 1656HFSC supports both link-sharing and guaranteed real-time services. 1657HFSC employs a service curve based QoS model, and its unique feature 1658is an ability to decouple delay and bandwidth allocation. 1659Requires 1660.Em ALTQ_RED 1661to use the RED queueing discipline on HFSC classes, or 1662.Em ALTQ_RIO 1663to use the RIO queueing discipline on HFSC classes. 1664This option assumes 1665.Em ALTQ . 1666.It Cd options ALTQ_PRIQ 1667Include support for ALTQ-implemented PRIQ (Priority Queueing). 1668PRIQ implements a simple priority-based queueing discipline. 1669A higher priority class is always served first. 1670Requires 1671.Em ALTQ_RED 1672to use the RED queueing discipline on HFSC classes, or 1673.Em ALTQ_RIO 1674to use the RIO queueing discipline on HFSC classes. 1675This option assumes 1676.Em ALTQ . 1677.It Cd options ALTQ_WFQ 1678Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1679WFQ implements a weighted-round robin scheduler for a set of queues. 1680A weight can be assigned to each queue to give a different proportion 1681of the link capacity. 1682A hash function is used to map a flow to one of a set of queues. 1683This option assumes 1684.Em ALTQ . 1685.It Cd options ALTQ_FIFOQ 1686Include support for ALTQ-implemented FIFO queueing. 1687FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1688This option assumes 1689.Em ALTQ . 1690.It Cd options ALTQ_RIO 1691Include support for ALTQ-implemented RIO (RED with In/Out). 1692The original RIO has 2 sets of RED parameters; one for in-profile 1693packets and the other for out-of-profile packets. 1694At the ingress of the network, profile meters tag packets as IN or 1695OUT based on contracted profiles for customers. 1696Inside the network, IN packets receive preferential treatment by 1697the RIO dropper. 1698ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1699PHB of DiffServ (RFC 2597). 1700This option assumes 1701.Em ALTQ . 1702.It Cd options ALTQ_BLUE 1703Include support for ALTQ-implemented Blue buffer management. 1704Blue is another active buffer management mechanism. 1705This option assumes 1706.Em ALTQ . 1707.It Cd options ALTQ_FLOWVALVE 1708Include support for ALTQ-implemented Flowvalve. 1709Flowvalve is a simple implementation of a RED penalty box that identifies 1710and punishes misbehaving flows. 1711This option requires 1712.Em ALTQ_RED 1713and assumes 1714.Em ALTQ . 1715.It Cd options ALTQ_CDNR 1716Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1717packet marking/manipulation. 1718Traffic conditioners are components to meter, mark, or drop incoming 1719packets according to some rules. 1720As opposed to queueing disciplines, traffic conditioners handle incoming 1721packets at an input interface. 1722This option assumes 1723.Em ALTQ . 1724.It Cd options ALTQ_NOPCC 1725Disables use of processor cycle counter to measure time in ALTQ. 1726This option should be defined for a non-Pentium i386 CPU which does not 1727have TSC, SMP (per-CPU counters are not in sync), or power management 1728which affects processor cycle counter. 1729This option assumes 1730.Em ALTQ . 1731.It Cd options ALTQ_IPSEC 1732Include support for IPsec in IPv4 ALTQ. 1733This option assumes 1734.Em ALTQ . 1735.It Cd options ALTQ_JOBS 1736Undocumented at this time. 1737.It Cd options ALTQ_AFMAP 1738Include support for an undocumented ALTQ feature that is used to map an IP 1739flow to an ATM VC (Virtual Circuit). 1740This option assumes 1741.Em ALTQ . 1742.It Cd options ALTQ_LOCALQ 1743Include support for ALTQ-implemented local queues. 1744Its practical use is undefined. 1745Assumes 1746.Em ALTQ . 1747.It Cd options SUBNETSARELOCAL 1748Sets default value for net.inet.ip.subnetsarelocal variable, which 1749controls whether non-directly-connected subnets of connected networks 1750are considered "local" for purposes of choosing the MSS for a TCP 1751connection. 1752This is mostly present for historic reasons and completely irrelevant if 1753you enable Path MTU discovery. 1754.It Cd options HOSTZEROBROADCAST 1755Sets default value for net.inet.ip.hostzerobroadcast variable, which 1756controls whether the zeroth host address of each connected subnet is 1757also considered a broadcast address. 1758Default value is "1", for compatibility with old systems; if this is 1759set to zero on all hosts on a subnet, you should be able to fit an extra 1760host per subnet on the 1761".0" address. 1762.It Cd options MCLSHIFT=value 1763This option is the base-2 logarithm of the size of mbuf clusters. 1764The 1765.Bx 1766networking stack keeps network packets in a linked 1767list, or chain, of kernel buffer objects called mbufs. 1768The system provides larger mbuf clusters as an optimization for 1769large packets, instead of using long chains for large packets. 1770The mbuf cluster size, 1771or 1772.Em MCLBYTES , 1773must be a power of two, and is computed as two raised to the power 1774.Em MCLSHIFT . 1775On systems with Ethernet network adaptors, 1776.Em MCLSHIFT 1777is often set to 11, giving 2048-byte mbuf clusters, large enough to 1778hold a 1500-byte 1779.Tn Ethernet 1780frame in a single cluster. 1781Systems with network interfaces supporting larger frame sizes like 1782.Tn ATM , 1783.Tn FDDI , 1784or 1785.Tn HIPPI 1786may perform better with 1787.Em MCLSHIFT 1788set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1789respectively. 1790.It Cd options NS 1791Include support for the 1792.Tn Xerox 1793.Tn XNS 1794protocol stack. 1795See 1796.Xr ns 4 1797for details. 1798.It Cd options ISO,TPIP 1799Include support for the ubiquitous 1800.Tn OSI 1801protocol stack. 1802See 1803.Xr iso 4 1804for details. 1805This option assumes 1806.Em INET . 1807.It Cd options EON 1808Include support for tunneling 1809.Tn OSI 1810protocols over 1811.Tn IP . 1812Known to be broken, or at least very fragile, and undocumented. 1813.It Cd options NETATALK 1814Include support for the 1815.Tn AppleTalk 1816protocol stack. 1817The kernel provides provision for the 1818.Em Datagram Delivery Protocol 1819(DDP), providing SOCK_DGRAM support and 1820.Tn AppleTalk 1821routing. 1822This stack is used by the 1823.Em NETATALK 1824package, which adds support for 1825.Tn AppleTalk 1826server services via user libraries and applications. 1827.It Cd options BLUETOOTH 1828Include support for the 1829.Tn Bluetooth 1830protocol stack. See 1831.Xr bluetooth 4 1832for details. 1833.It Cd options IPNOPRIVPORTS 1834Normally, only root can bind a socket descriptor to a so-called 1835.Dq privileged 1836.Tn TCP 1837port, that is, a port number in the range 0-1023. 1838This option eliminates those checks from the kernel. 1839This can be useful if there is a desire to allow daemons without 1840privileges to bind those ports, e.g., on firewalls. 1841The security tradeoffs in doing this are subtle. 1842This option should only be used by experts. 1843.It Cd options TCP_COMPAT_42 1844.Tn TCP 1845bug compatibility with 1846.Bx 4.2 . 1847In 1848.Bx 4.2 , 1849.Tn TCP 1850sequence numbers were 32-bit signed values. 1851Modern implementations of TCP use unsigned values. 1852This option clamps the initial sequence number to start in 1853the range 2^31 rather than the full unsigned range of 2^32. 1854Also, under 1855.Bx 4.2 , 1856keepalive packets must contain at least one byte or else 1857the remote end would not respond. 1858.It Cd options TCP_DEBUG 1859Record the last 1860.Em TCP_NDEBUG 1861TCP packets with SO_DEBUG set, and decode to the console if 1862.Em tcpconsdebug 1863is set. 1864.It Cd options TCP_NDEBUG 1865Number of packets to record for 1866.Em TCP_DEBUG . 1867Defaults to 100. 1868.It Cd options TCP_SENDSPACE=value 1869.It Cd options TCP_RECVSPACE=value 1870These options set the max TCP window size to other sizes than the default. 1871The TCP window sizes can be altered via 1872.Xr sysctl 8 1873as well. 1874.It Cd options TCP_INIT_WIN=value 1875This option sets the initial TCP window size for non-local connections, 1876which is used when the transmission starts. 1877The default size is 1, but if the machine should act more aggressively, 1878the initial size can be set to some other value. 1879The initial TCP window size can be set via 1880.Xr sysctl 8 1881as well. 1882.It Cd options PFIL_HOOKS 1883This option turns on the packet filter interface hooks. 1884See 1885.Xr pfil 9 1886for details. 1887This option assumes 1888.Em INET . 1889.It Cd options IPFILTER_LOG 1890This option, in conjunction with 1891.Em pseudo-device ipfilter , 1892enables logging of IP packets using ip-filter. 1893.It Cd options IPFILTER_DEFAULT_BLOCK 1894This option sets the default policy of ip-filter. 1895If it is set, ip-filter will block packets by default. 1896.It Cd options BRIDGE_IPF 1897This option causes 1898.Em bridge 1899devices to use the IP and/or IPv6 filtering hooks, forming 1900a link-layer filter that uses protocol-layer rules. 1901This option assumes the presence of 1902.Em pseudo-device ipfilter . 1903.It Cd options MBUFTRACE 1904This option can help track down mbuf leaks. 1905When enabled, mbufs are tagged with the devices and protocols using them, 1906which slightly decreases network performance. 1907This additional information can be viewed with 1908.Xr netstat 1 : 1909.Dl Ic netstat Fl mssv 1910Not all devices or protocols support this option. 1911.El 1912.Ss Sysctl Related Options 1913.Bl -ohang 1914.It Cd options SYSCTL_DISALLOW_CREATE 1915Disallows the creation or deletion of nodes from the sysctl tree, as 1916well as the assigning of descriptions to nodes that lack them, by any 1917process. 1918These operations are still available to kernel sub-systems, including 1919loadable kernel modules. 1920.It Cd options SYSCTL_DISALLOW_KWRITE 1921Prevents processes from adding nodes to the sysctl tree that make 1922existing kernel memory areas writeable. 1923Sections of kernel memory can still be read and new nodes that own 1924their own data may still be writeable. 1925.It Cd options SYSCTL_DEBUG_SETUP 1926Causes the SYSCTL_SETUP routines to print a brief message when they 1927are invoked. 1928This is merely meant as an aid in determining the order in which 1929sections of the tree are created. 1930.It Cd options SYSCTL_DEBUG_CREATE 1931Prints a message each time 1932.Fn sysctl_create , 1933the function that adds nodes to the tree, is called. 1934.It Cd options SYSCTL_INCLUDE_DESCR 1935Causes the kernel to include short, human readable descriptions for 1936nodes in the sysctl tree. 1937The descriptions can be retrieved programmatically (see 1938.Xr sysctl 3 ) , 1939or by the sysctl binary itself (see 1940.Xr sysctl 8 ) . 1941The descriptions are meant to give an indication of the purpose and/or 1942effects of a given node's value, not replace the documentation for the 1943given subsystem as a whole. 1944.El 1945.Ss System V IPC Options 1946.Bl -ohang 1947.It Cd options SYSVMSG 1948Includes support for 1949.At V 1950style message queues. 1951See 1952.Xr msgctl 2 , 1953.Xr msgget 2 , 1954.Xr msgrcv 2 , 1955.Xr msgsnd 2 . 1956.It Cd options SYSVSEM 1957Includes support for 1958.At V 1959style semaphores. 1960See 1961.Xr semctl 2 , 1962.Xr semget 2 , 1963.Xr semop 2 . 1964.It Cd options SEMMNI=value 1965Sets the number of 1966.At V 1967style semaphore identifiers. 1968The GENERIC config file for your port will have the default. 1969.It Cd options SEMMNS=value 1970Sets the number of 1971.At V 1972style semaphores in the system. 1973The GENERIC config file for your port will have the default. 1974.It Cd options SEMUME=value 1975Sets the maximum number of undo entries per process for 1976.At V 1977style semaphores. 1978The GENERIC config file for your port will have the default. 1979.It Cd options SEMMNU=value 1980Sets the number of undo structures in the system for 1981.At V 1982style semaphores. 1983The GENERIC config file for your port will have the default. 1984.It Cd options SYSVSHM 1985Includes support for 1986.At V 1987style shared memory. 1988See 1989.Xr shmat 2 , 1990.Xr shmctl 2 , 1991.Xr shmdt 2 , 1992.Xr shmget 2 . 1993.It Cd options SHMMAXPGS=value 1994Sets the maximum number of 1995.At V 1996style shared memory pages that are available through the 1997.Xr shmget 2 1998system call. 1999Default value is 1024 on most ports. 2000See 2001.Pa /usr/include/machine/vmparam.h 2002for the default. 2003.El 2004.Ss VM Related Options 2005.Bl -ohang 2006.It Cd options NMBCLUSTERS=value 2007The number of mbuf clusters the kernel supports. 2008Mbuf clusters are MCLBYTES in size (usually 2k). 2009This is used to compute the size of the kernel VM map 2010.Em mb_map , 2011which maps mbuf clusters. 2012Default on most ports is 1024 (2048 with 2013.Dq options GATEWAY 2014). 2015See 2016.Pa /usr/include/machine/param.h 2017for exact default information. 2018Increase this value if you get 2019.Dq mclpool limit reached 2020messages. 2021.It Cd options NKMEMPAGES=value 2022.It Cd options NKMEMPAGES_MIN=value 2023.It Cd options NKMEMPAGES_MAX=value 2024Size of kernel VM map 2025.Em kmem_map , 2026in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2027from the 2028.Xr sysctl 8 2029variable 2030.Em hw.pagesize 2031). 2032This VM map is used to map the kernel malloc arena. 2033The kernel attempts to auto-size this map based on the amount of 2034physical memory in the system. 2035Platform-specific code may place bounds on this computed size, 2036which may be viewed with the 2037.Xr sysctl 8 2038variable 2039.Em vm.nkmempages . 2040See 2041.Pa /usr/include/machine/param.h 2042for the default upper and lower bounds. 2043The related options 2044.Sq NKMEMPAGES_MIN 2045and 2046.Sq NKMEMPAGES_MAX 2047allow the bounds to be overridden in the kernel configuration file. 2048These options are provided in the event the computed value is 2049insufficient resulting in an 2050.Dq out of space in kmem_map 2051panic. 2052.It Cd options SB_MAX=value 2053Sets the max size in bytes that a socket buffer is allowed to occupy. 2054The default is 256k, but sometimes it needs to be increased, for example 2055when using large TCP windows. 2056This option can be changed via 2057.Xr sysctl 8 2058as well. 2059.It Cd options SOMAXKVA=value 2060Sets the maximum size of kernel virtual memory that the socket buffers 2061are allowed to use. 2062The default is 16MB, but in situations where for example large TCP 2063windows are used this value must also be increased. 2064This option can be changed via 2065.Xr sysctl 8 2066as well. 2067.It Cd options BUFCACHE=value 2068Size of the buffer cache as a percentage of total available 2069.Tn RAM . 2070Ignored if BUFPAGES is also specified. 2071.It Cd options NBUF=value 2072Sets the number of buffer headers available, i.e., the number of 2073open files that may have a buffer cache entry. 2074Each buffer header 2075requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2076The default value is machine dependent, but is usually equal to the 2077value of BUFPAGES. 2078If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2079then NBUF may be reduced at run time so that the storage allocated 2080for buffer headers doesn't exceed that limit. 2081.It Cd options BUFPAGES=value 2082These options set the number of pages available for the buffer cache. 2083Their default value is a machine dependent value, often calculated as 2084between 5% and 10% of total available 2085.Tn RAM . 2086.It Cd options MAXTSIZ=bytes 2087Sets the maximum size limit of a process' text segment. 2088See 2089.Pa /usr/include/machine/vmparam.h 2090for the port-specific default. 2091.It Cd options DFLDSIZ=bytes 2092Sets the default size limit of a process' data segment, the value that 2093will be returned as the soft limit for 2094.Dv RLIMIT_DATA 2095(as returned by 2096.Xr getrlimit 2 ) . 2097See 2098.Pa /usr/include/machine/vmparam.h 2099for the port-specific default. 2100.It Cd options MAXDSIZ=bytes 2101Sets the maximum size limit of a process' data segment, the value that 2102will be returned as the hard limit for 2103.Dv RLIMIT_DATA 2104(as returned by 2105.Xr getrlimit 2 ) . 2106See 2107.Pa /usr/include/machine/vmparam.h 2108for the port-specific default. 2109.It Cd options DFLSSIZ=bytes 2110Sets the default size limit of a process' stack segment, the value that 2111will be returned as the soft limit for 2112.Dv RLIMIT_STACK 2113(as returned by 2114.Xr getrlimit 2 ) . 2115See 2116.Pa /usr/include/machine/vmparam.h 2117for the port-specific default. 2118.It Cd options MAXSSIZ=bytes 2119Sets the maximum size limit of a process' stack segment, the value that 2120will be returned as the hard limit for 2121.Dv RLIMIT_STACK 2122(as returned by 2123.Xr getrlimit 2 ) . 2124See 2125.Pa /usr/include/machine/vmparam.h 2126for the port-specific default. 2127.It Cd options DUMP_ON_PANIC=integer 2128Defaults to one. 2129If set to zero, the kernel will not dump to the dump device when 2130it panics, though dumps can still be forced via 2131.Xr ddb 4 2132with the 2133.Dq sync 2134command. 2135Note that this sets the value of the 2136.Em kern.dump_on_panic 2137.Xr sysctl 3 2138variable which may be changed at run time -- see 2139.Xr sysctl 8 2140for details. 2141.It Cd options USE_TOPDOWN_VM 2142User space memory allocations (as made by 2143.Xr mmap 2 ) 2144will be arranged in a 2145.Dq top down 2146fashion instead of the traditional 2147.Dq upwards from MAXDSIZ \+ vm_daddr 2148method. 2149This includes the placement of 2150.Xr ld.so 1 . 2151Arranging memory in this manner allows either (or both of) the heap or 2152.Xr mmap 2 2153allocated space to grow larger than traditionally possible. 2154This option is not available on all ports, but is instead expected to be 2155offered on a port-by-port basis, after which some ports will commit to 2156using it by default. 2157See the files 2158.Pa /usr/include/uvm/uvm_param.h 2159for some implementation details, and 2160.Pa /usr/include/machine/vmparam.h 2161for port specific details including availability. 2162.It Cd options VMSWAP 2163Enable paging device/file support. 2164This option is on by default. 2165.It Cd options PDPOLICY_CLOCKPRO 2166Use CLOCK-Pro, an alternative page replace policy. 2167.El 2168.Ss Security Options 2169.Bl -ohang 2170.It Cd options INSECURE 2171Hardwires the kernel security level at \-1. 2172This means that the system 2173always runs in secure level \-1 mode, even when running multiuser. 2174See the manual page for 2175.Xr init 8 2176for details on the implications of this. 2177The kernel secure level may manipulated by the superuser by altering the 2178.Em kern.securelevel 2179.Xr sysctl 3 2180variable (the secure level may only be lowered by a call from process ID 1, 2181i.e., 2182.Xr init 8 ) . 2183See also 2184.Xr sysctl 8 2185and 2186.Xr sysctl 3 . 2187.It Cd options VERIFIED_EXEC_FP_MD5 2188Enables support for MD5 hashes in Veriexec. 2189.It Cd options VERIFIED_EXEC_FP_SHA1 2190Enables support for SHA1 hashes in Veriexec. 2191.It Cd options VERIFIED_EXEC_FP_RMD160 2192Enables support for RMD160 hashes in Veriexec. 2193.It Cd options VERIFIED_EXEC_FP_SHA256 2194Enables support for SHA256 hashes in Veriexec. 2195.It Cd options VERIFIED_EXEC_FP_SHA384 2196Enables support for SHA384 hashes in Veriexec. 2197.It Cd options VERIFIED_EXEC_FP_SHA512 2198Enables support for SHA512 hashes in Veriexec. 2199.It Cd options PAX_MPROTECT=value 2200Enables PaX MPROTECT, 2201.Xr mprotect 2 2202restrictions from the PaX project. 2203.Pp 2204The 2205.Ar value 2206is the default value for the 2207.Em global_protection 2208knob, see 2209.Xr sysctl 3 . 2210If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2211using 2212.Xr paxctl 1 . 2213If 1, PaX MPROTECT will be enabled to all programs, and exemption can 2214be done using 2215.Xr paxctl 1 . 2216.El 2217.Ss amiga-specific Options 2218.Bl -ohang 2219.It Cd options BB060STUPIDROM 2220When the bootloader (which passes 2221.Tn AmigaOS 2222.Tn ROM 2223information) claims we have a 68060 2224.Tn CPU 2225without 2226.Tn FPU , 2227go look into the Processor Configuration Register (PCR) to find out. 2228You need this with 2229.Tn Amiga 2230.Tn ROM Ns s 2231up to (at least) V40.xxx (OS3.1), 2232when you boot via the bootblocks and don't have a DraCo. 2233.It Cd options IOBZCLOCK=frequency 2234The IOBlix boards come with two different serial master clocks: older ones 2235use 24 MHz, newer ones use 22.1184 MHz. 2236The driver normally assumes the latter. 2237If your board uses 24 MHz, you can recompile your kernel with 2238options IOBZCLOCK=24000000 2239or patch the kernel variable 2240.Tn iobzclock 2241to the same value. 2242.It Cd options LIMITMEM=value 2243If there, limit the part of the first memory bank used by 2244.Nx 2245to value megabytes. 2246Default is unlimited. 2247.It Cd options NKPTADD=addvalue 2248.It Cd options NKPTADDSHIFT=shiftvalue 2249The 2250.Tn CPU 2251specific 2252.Tn MMU 2253table for the kernel is pre-allocated at kernel startup time. 2254Part of it is scaled with 2255.Va maxproc , 2256to have enough room to hold the user program 2257.Tn MMU 2258tables; the second part is a fixed amount for the kernel itself. 2259.Pp 2260The third part accounts for the size of the file buffer cache. 2261Its size is either 2262.Dv NKPTADD 2263pages (if defined) or memory size in bytes divided by two to 2264the power of 2265.Dv NKPTADDSHIFT . 2266The default is undefined 2267.Dv NKPTADD 2268and 2269.Dv NKPTADDSHIFT=24 , 2270allowing for 16 buffers per megabyte of main memory (while 2271a GENERIC kernel allocates about half of that). 2272When you get "can't get KPT page" panics, you should increase 2273.Dv NKPTADD 2274(if defined), or decrease 2275.Dv NKPTADDSHIFT 2276by one. 2277.It Cd options P5PPC68KBOARD 2278Add special support for Phase5 mixed 68k+PPC boards. 2279Currently, this only affects rebooting from 2280.Nx 2281and is only needed on 68040+PPC, not on 228268060+PPC; without this, affected machines will hang after 2283.Nx 2284has shut 2285down and will only restart after a keyboard reset or a power cycle. 2286.El 2287.Ss arm32-specific Options 2288.Bl -ohang 2289.It Cd options FRENCH_KBD 2290Include translation for French keyboards when using 2291.Em pccons 2292on a Shark. 2293.It Cd options FINNISH_KBD 2294Include translation for Finnish keyboards when using 2295.Em pccons 2296on a Shark. 2297.It Cd options GERMAN_KBD 2298Include translation for German keyboards when using 2299.Em pccons 2300on a Shark. 2301.It Cd options NORWEGIAN_KBD 2302Include translation for French keyboards when using 2303.Em pccons 2304on a Shark. 2305.El 2306.Ss amd64-specific Options 2307.Bl -ohang 2308.It Cd options POWERNOW_K8 2309Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2310Technology, used to change the cpu and voltage frequency 2311on the fly. 2312.El 2313.Ss atari-specific Options 2314.Bl -ohang 2315.It Cd options DISKLABEL_AHDI 2316Include support for AHDI (native Atari) disklabels. 2317.It Cd options DISKLABEL_NBDA 2318Include support for 2319.Nx Ns Tn /atari 2320labels. 2321If you don't set this option, it will be set automatically. 2322.Nx Ns Tn /atari 2323will not work without it. 2324.It Cd options FALCON_SCSI 2325Include support for the 5380-SCSI configuration as found on the Falcon. 2326.It Cd options RELOC_KERNEL 2327If set, the kernel will relocate itself to TT-RAM, if possible. 2328This will give you a slightly faster system. 2329.Em Beware 2330that on some TT030 systems, 2331the system will frequently dump with MMU-faults with this option enabled. 2332.It Cd options SERCONSOLE 2333Allow the modem1-port to act as the system-console. 2334A carrier should be active on modem1 during system boot to active 2335the console functionality. 2336.It Cd options TT_SCSI 2337Include support for the 5380-SCSI configuration as found on the TT030 2338and Hades. 2339.El 2340.Ss i386-specific Options 2341.Bl -ohang 2342.It Cd options I386_CPU,I486_CPU,I586_CPU,I686_CPU 2343Include support for a particular class of 2344.Tn CPU 2345.Po 2346.Tn i386 , 2347.Tn i486 , 2348.Tn Pentium , 2349or 2350.Tn Pentium Pro 2351.Pc . 2352If the appropriate class for your 2353.Tn CPU 2354is not configured, the kernel will use the highest class available 2355that will work. 2356In general, using the correct 2357.Tn CPU 2358class will result in the best performance. 2359At least one of these options must be present. 2360.It Cd options ENHANCED_SPEEDSTEP 2361Include support for the 2362.Tn Enhanced SpeedStep Technology 2363present in newer 2364.Tn CPU Ns s . 2365.It Cd options EST_FREQ_USERWRITE 2366Allow any user to change the frequency of an 2367.Tn Enhanced SpeedStep Technology 2368capable 2369.Tn CPU . 2370.It Cd options POWERNOW_K7 2371Include support for the AMD 2372.Tn PowerNow! Technology 2373present in AMD Athlon Mobile processors. 2374.It Cd options CPURESET_DELAY=value 2375Specifies the time (in millisecond) to wait before doing a hardware reset 2376in the last phase of a reboot. 2377This gives the user a chance to see error messages from the shutdown 2378operations (like NFS unmounts, buffer cache flush, etc ...). 2379Setting this to 0 will disable the delay. 2380Default is 2 seconds. 2381.It Cd options MATH_EMULATE 2382Include the floating point emulator. 2383This is useful only for 2384.Tn CPU Ns s 2385that lack an 2386internal Floating Point Unit 2387.Pq Tn FPU 2388or co-processor. 2389.It Cd options VM86 2390Include support for virtual 8086 mode, used by 2391.Tn DOS 2392emulators and X servers to run BIOS code, e.g., for some VESA routines. 2393.It Cd options USER_LDT 2394Include i386-specific system calls for modifying the local descriptor table, 2395used by Windows emulators. 2396.It Cd options REALBASEMEM=integer 2397Overrides the base memory size passed in from the boot block. 2398(Value given in kilobytes.) 2399Use this option only if the boot block reports the size incorrectly. 2400(Note that some 2401.Tn BIOS Ns es 2402put the extended 2403.Tn BIOS 2404data area at the top of base memory, and therefore report a smaller 2405base memory size to prevent programs overwriting it. 2406This is correct behavior, and you should not use the 2407.Em REALBASEMEM 2408option to access this memory). 2409.It Cd options REALEXTMEM=integer 2410Overrides the extended memory size passed in from the boot block. 2411(Value given in kilobytes. 2412Extended memory does not include the first megabyte.) 2413Use this option only if the boot block reports the size incorrectly. 2414.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2415Select a non-US keyboard layout for the 2416.Em pccons 2417console driver. 2418.It Cd options CYRIX_CACHE_WORKS 2419Relevant only to the Cyrix 486DLC CPU. 2420This option is used to turn on the cache in hold-flush mode. 2421It is not turned on by default because it is known to have problems in 2422certain motherboard implementations. 2423.It Cd options CYRIX_CACHE_REALLY_WORKS 2424Relevant only to the Cyrix 486DLC CPU. 2425This option is used to turn on the cache in write-back mode. 2426It is not turned on by default because it is known to have problems in 2427certain motherboard implementations. 2428In order for this option to take effect, option 2429.Em CYRIX_CACHE_WORKS 2430must also be specified. 2431.It Cd options PCIBIOS 2432Enable support for initializing the 2433.Tn PCI 2434bus using information from the 2435.Tn BIOS . 2436See 2437.Xr pcibios 4 2438for details. 2439.It Cd options KSTACK_CHECK_DR0 2440Detect kernel stack overflow using DR0 register. 2441This option uses DR0 register exclusively so you can't use DR0 register for 2442other purpose (e.g., hardware breakpoint) if you turn this on. 2443.It Cd options MTRR 2444Include support for accessing MTRR registers from user-space. 2445See 2446.Xr i386_get_mtrr 2 . 2447.It Cd options BEEP_ONHALT 2448Make the system speaker emit several beeps when it is completely safe to 2449power down the computer after a 2450.Xr halt 8 2451command. 2452Requires 2453.Xr sysbeep 4 2454support. 2455.It Cd options BEEP_ONHALT_COUNT=times 2456Number of times to beep the speaker when 2457.Cd options BEEP_ONHALT 2458is enabled. 2459Defaults to 3. 2460.It Cd options BEEP_ONHALT_PITCH=hz 2461The tone frequency used when 2462.Cd options BEEP_ONHALT 2463option, in hertz. 2464Defaults to 1500. 2465.It Cd options BEEP_ONHALT_PERIOD=msecs 2466The duration of each beep when 2467.Cd options BEEP_ONHALT 2468is enabled, in milliseconds. 2469Defaults to 250. 2470.It Cd options MULTIBOOT 2471Makes the kernel Multiboot-compliant, allowing it to be booted through 2472a Multiboot-compliant boot manager such as GRUB. 2473See 2474.Xr multiboot 8 2475for more information. 2476.It Cd options MULTIBOOT_SYMTAB_SPACE=nbytes 2477Space (in bytes) reserved in memory to store the kernel's symbol table. 2478If the symbol table is bigger than this space, it will not be loaded; 2479if it is smaller, the unused memory will be claimed by the kernel and 2480used normally. 2481You shouldn't need to touch this variable. 2482Defaults to 1048576 bytes (one megabyte). 2483.El 2484.Ss isa-specific Options 2485Options specific to 2486.Xr isa 4 2487busses. 2488.Bl -ohang 2489.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2490Control the section of IO bus space used for PCMCIA bus space mapping. 2491Ideally the probed defaults are satisfactory, however in practice 2492that is not always the case. 2493See 2494.Xr pcmcia 4 2495for details. 2496.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2497Controls the allowable interrupts that may be used for 2498.Tn PCMCIA 2499devices. 2500This mask is a logical-or of power-of-2s of allowable interrupts: 2501.Bd -literal -offset 04n 2502.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2503 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2504 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2505 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2506 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2507.Ed 2508.It Cd options PCKBC_CNATTACH_SELFTEST 2509Perform a self test of the keyboard controller before attaching it as a 2510console. 2511This might be necessary on machines where we boot on cold iron, and 2512pckbc refuses to talk until we request a self test. 2513Currently only the netwinder port uses it. 2514.It Cd options PCKBD_CNATTACH_MAY_FAIL 2515If this option is set the PS/2 keyboard will not be used as the console 2516if it cannot be found during boot. 2517This allows other keyboards, like USB, to be the console keyboard. 2518.It Cd options PCKBD_LAYOUT=layout 2519Sets the default keyboard layout, see 2520.Xr pckbd 4 . 2521.El 2522.Ss m68k-specific Options 2523.Bl -ohang 2524.It Cd options FPU_EMULATE 2525Include support for MC68881/MC68882 emulator. 2526.It Cd options FPSP 2527Include support for 68040 floating point. 2528.It Cd options M68020,M68030,M68040,M68060 2529Include support for a specific 2530.Tn CPU , 2531at least one (the one you are using) should be specified. 2532.It Cd options M060SP 2533Include software support for 68060. 2534This provides emulation of unimplemented 2535integer instructions as well as emulation of unimplemented floating point 2536instructions and data types and software support for floating point traps. 2537.El 2538.Ss powerpc-specific Options (OEA Only) 2539.Bl -ohang 2540.It Cd options PMAP_MEMLIMIT=value 2541Limit the amount of memory seen by the kernel to 2542.Ar value 2543bytes. 2544.It Cd options PTEGCOUNT=value 2545Specify the size of the page table as 2546.Ar value 2547PTE groups. 2548Normally, one PTEG is allocated per physical page frame. 2549.El 2550.Ss sparc-specific Options 2551.Bl -ohang 2552.It Cd options AUDIO_DEBUG 2553Enable simple event debugging of the logging of the 2554.Xr audio 4 2555device. 2556.It Cd options BLINK 2557Enable blinking of LED. 2558Blink rate is full cycle every N seconds for 2559N \*[Lt] then current load average. 2560See 2561.Xr getloadavg 3 . 2562.\" .It Cd options COLORFONT_CACHE 2563.\" What does this do? 2564.It Cd options COUNT_SW_LEFTOVERS 2565Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2566sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2567variables accessible from 2568.Xr ddb 4 . 2569See 2570.Xr sw 4 . 2571.It Cd options DEBUG_ALIGN 2572Adds debugging messages calls when user-requested alignment fault 2573handling happens. 2574.It Cd options DEBUG_EMUL 2575Adds debugging messages calls for emulated floating point and 2576alignment fixing operations. 2577.It Cd options DEBUG_SVR4 2578Prints registers messages calls for emulated SVR4 getcontext and 2579setcontext operations. 2580See 2581.Em options COMPAT_SVR4 . 2582.It Cd options EXTREME_DEBUG 2583Adds debugging functions callable from 2584.Xr ddb 4 . 2585The debug_pagetables, test_region and print_fe_map 2586functions print information about page tables for the SUN4M 2587platforms only. 2588.It Cd options EXTREME_EXTREME_DEBUG 2589Adds extra info to 2590.Em options EXTREME_DEBUG . 2591.It Cd options FPU_CONTEXT 2592Make 2593.Em options COMPAT_SVR4 2594getcontext and setcontext include floating point registers. 2595.It Cd options MAGMA_DEBUG 2596Adds debugging messages to the 2597.Xr magma 4 2598device. 2599.It Cd options RASTERCONS_FULLSCREEN 2600Use the entire screen for the console. 2601.It Cd options RASTERCONS_SMALLFONT 2602Use the Fixed font on the console, instead of the normal font. 2603.It Cd options SUN4 2604Support sun4 class machines. 2605.It Cd options SUN4C 2606Support sun4c class machines. 2607.It Cd options SUN4M 2608Support sun4m class machines. 2609.It Cd options SUN4_MMU3L 2610.\" XXX ??? 2611Enable support for sun4 3-level MMU machines. 2612.It Cd options V9 2613Enable SPARC V9 assembler in 2614.Xr ddb 4 . 2615.El 2616.Ss sparc64-specific Options 2617.Bl -ohang 2618.It Cd options AUDIO_DEBUG 2619Enable simple event debugging of the logging of the 2620.Xr audio 4 2621device. 2622.It Cd options BLINK 2623Enable blinking of LED. 2624Blink rate is full cycle every N seconds for 2625N \*[Lt] then current load average. 2626See 2627.Xr getloadavg 3 . 2628.El 2629.Ss x68k-specific Options 2630.Bl -ohang 2631.It Cd options EXTENDED_MEMORY 2632Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2633.It Cd options JUPITER 2634Include support for Jupiter-X MPU accelerator 2635.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2636Use the built-in serial port as the system-console. 2637Speed is specified in bps, defaults to 9600. 2638.It Cd options ITE_KERNEL_ATTR=value 2639Set the kernel message attribute for ITE. 2640Value, an integer, is a logical or of the following values: 2641.Bl -tag -width 4n -compact -offset indent 2642.It 1 2643color inversed 2644.It 2 2645underlined 2646.It 4 2647bolded 2648.El 2649.El 2650.\" The following requests should be uncommented and used where appropriate. 2651.\" .Sh FILES 2652.\" .Sh EXAMPLES 2653.Sh SEE ALSO 2654.Xr config 1 , 2655.Xr gdb 1 , 2656.Xr ktrace 1 , 2657.Xr pmc 1 , 2658.Xr quota 1 , 2659.Xr vndcompress 1 , 2660.Xr gettimeofday 2 , 2661.Xr i386_get_mtrr 2 , 2662.Xr i386_iopl 2 , 2663.Xr msgctl 2 , 2664.Xr msgget 2 , 2665.Xr msgrcv 2 , 2666.Xr msgsnd 2 , 2667.Xr ntp_adjtime 2 , 2668.Xr ntp_gettime 2 , 2669.Xr semctl 2 , 2670.Xr semget 2 , 2671.Xr semop 2 , 2672.Xr shmat 2 , 2673.Xr shmctl 2 , 2674.Xr shmdt 2 , 2675.Xr shmget 2 , 2676.Xr sysctl 3 , 2677.Xr apm 4 , 2678.Xr ddb 4 , 2679.Xr inet 4 , 2680.Xr iso 4 , 2681.Xr lkm 4 , 2682.Xr md 4 , 2683.Xr ns 4 , 2684.Xr pcibios 4 , 2685.Xr pcmcia 4 , 2686.Xr ppp 4 , 2687.Xr userconf 4 , 2688.Xr vnd 4 , 2689.Xr wscons 4 , 2690.Xr config 5 , 2691.Xr edquota 8 , 2692.Xr init 8 , 2693.Xr mdsetimage 8 , 2694.Xr mount_cd9660 8 , 2695.Xr mount_fdesc 8 , 2696.Xr mount_kernfs 8 , 2697.Xr mount_lfs 8 , 2698.Xr mount_mfs 8 , 2699.Xr mount_msdos 8 , 2700.Xr mount_nfs 8 , 2701.Xr mount_ntfs 8 , 2702.Xr mount_null 8 , 2703.Xr mount_portal 8 , 2704.Xr mount_procfs 8 , 2705.Xr mount_udf 8 , 2706.Xr mount_umap 8 , 2707.Xr mount_union 8 , 2708.Xr mrouted 8 , 2709.Xr newfs_lfs 8 , 2710.Xr ntpd 8 , 2711.Xr quotaon 8 , 2712.Xr rpc.rquotad 8 , 2713.Xr sysctl 8 2714.Sh HISTORY 2715The 2716.Nm 2717man page first appeared in 2718.Nx 1.3 . 2719.Sh BUGS 2720The 2721.Em EON 2722option should be a pseudo-device, and is also very fragile. 2723