1.\" $NetBSD: options.4,v 1.375 2009/03/11 19:54:05 joerg 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 February 6, 2009 34.Dt OPTIONS 4 35.Os 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Qq Ar filename 66Conditionally includes another kernel configuration file whose name is 67.Ar filename , 68which may be double-quoted and may be an explicit path or relative to 69the kernel source directory. 70Failure to open the named file is ignored. 71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ 72Oo dumps on Ar dumpdev Oc 73Defines a configuration whose kernel executable is named 74.Ar exec_name , 75normally 76.Dq netbsd , 77with its root file system of type 78.Ar fstype 79on the device 80.Ar rootdev , 81and optionally specifying the location of kernel core dumps on the device 82.Ar dumpdev . 83.Ar dev 84or 85.Ar dumpdev 86and 87.Ar fstype 88may be specified as 89.Dq \&? , 90which is a wild card. 91The root 92.Ar fstype 93and 94.Ar dumpdev 95are optional and assumed to be wild carded if they are not specified. 96.It Ar device_instance No at Ar attachment \ 97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc 98Define an instance of the device driver 99.Ar device_instance 100that attaches to the bus or device named 101.Ar attachment . 102An 103.Ar attachment 104may require additional information on where the device can be found, such 105as an address, channel, function, offset, and/or slot, referred to as 106.Ar locators , 107whose 108.Ar value 109often may be a wild card, 110.Dq \&? . 111Some device drivers have one or more 112.Ar flags 113that can be adjusted to affect the way they operate. 114.It Sy file-system Ar fs_name Op , Ar fs_name Op ... 115Include support for the file-system 116.Ar fs_name . 117.It Sy ident Qq Ar string 118Sets the kernel identification string to 119.Ar string . 120.It Sy include Qq Ar filename 121Functions the same as 122.Ar cinclude , 123except failure to open 124.Ar filename 125produces a fatal error. 126.It Sy options Ar option_name Op , Ar option_name=value Op ... 127Specifies (or sets) the option, or comma-separated list of options, 128.Ar option_name . 129Some options expect to be assigned a value, which may be an integer, 130a double-quoted word, a bare word, or an empty string 131.Pq Qq . 132Note that those are eventually handled by the C compiler, so the rules 133of that language apply. 134.Pp 135.Em Note : 136Options that are not defined by device definition files are passed to 137the compile process as 138.Fl D 139flags to the C compiler. 140.It Sy makeoptions Ar name=value 141Defines a 142.Xr make 1 143macro 144.Ar name 145with the value 146.Ar value 147in the kernel Makefile. 148.It Sy maxusers Ar integer 149Set the maxusers variable in the kernel. 150.It Sy no Ar keyword Ar name Op Ar arguments Op ... 151For the 152.Xr config 1 153.Ar keywords 154file-system, makeoptions, options, and pseudo-device, 155.Ar no 156removes the file-system, makeoption, options, or pseudo-device, 157.Ar name . 158This is useful when a kernel configuration file includes another which 159has undesired options. 160.Pp 161For example, a local configuration file that wanted the kitchen sink, but 162not COMPAT_09 or bridging, might be: 163.Bd -literal -offset indent 164include "arch/i386/conf/GENERIC" 165no options COMPAT_09 166no pseudo-device bridge 167.Ed 168.It Sy pseudo-device Ar name Op Ar N 169Includes support for the pseudo-device 170.Ar name . 171Some pseudo-devices can have multiple or 172.Ar N 173instances. 174.El 175.Ss Compatibility Options 176.Bl -ohang 177.It Cd options COMPAT_09 178Enable binary compatibility with 179.Nx 0.9 . 180This enables support for 18116-bit user, group, and process IDs (following revisions support 18232-bit identifiers). 183It also allows the use of the deprecated 184.Xr getdomainname 3 , 185.Xr setdomainname 3 , 186and 187.Xr uname 3 188syscalls. 189This option also allows using numeric file system identifiers rather 190than strings. 191Post 192.Nx 0.9 193versions use string identifiers. 194.It Cd options COMPAT_10 195Enable binary compatibility with 196.Nx 1.0 . 197This option allows the use of the file system name of 198.Dq ufs 199as an alias for 200.Dq ffs . 201The name 202.Dq ffs 203should be used post 1.0 in 204.Pa /etc/fstab 205and other files. 206It also adds old syscalls for the 207.At V 208shared memory interface. 209This was changed post 1.0 to work on 64-bit architectures. 210This option also enables 211.Dq sgtty 212compatibility, without which programs using the old interface produce 213an 214.Dq inappropriate ioctl 215error, and 216.Pa /dev/io 217only works when this option is set in the kernel, 218see 219.Xr io 4 220on ports that support it. 221.It Cd options COMPAT_11 222Enable binary compatibility with 223.Nx 1.1 . 224This allows binaries running on the i386 port to gain direct access to 225the io ports by opening 226.Pa /dev/io 227read/write. 228This functionality was replaced by 229.Xr i386_iopl 2 230post 1.1. 231On the 232.Tn Atari 233port, the location of the disk label was moved after 1.1. 234When the 235.Em COMPAT_11 236option is set, the kernel will read (pre) 1.1 style disk labels as a 237last resort. 238When a disk label is re-written, the old style label will be replaced 239with a post 1.1 style label. 240This also enables the 241.Em EXEC_ELF_NOTELESS 242option. 243.It Cd options COMPAT_12 244Enable binary compatibility with 245.Nx 1.2 . 246This allows the use of old syscalls for 247.Fn reboot 248and 249.Fn swapon . 250The syscall numbers were changed post 1.2 to add functionality to the 251.Xr reboot 2 252syscall, and the new 253.Xr swapctl 2 254interface was introduced. 255This also enables the 256.Em EXEC_ELF_NOTELESS 257option. 258.It Cd options COMPAT_13 259Enable binary compatibility with 260.Nx 1.3 . 261This allows the use of old syscalls for 262.Fn sigaltstack , 263and also enables the old 264.Xr swapctl 2 265command 266.Dv SWAP_STATS 267(now called 268.Dv SWAP_OSTATS ) , 269which does not include the 270.Fa se_path 271member of 272.Va struct swapent . 273.It Cd options COMPAT_14 274Enable binary compatibility with 275.Nx 1.4 . 276This allows some old 277.Xr ioctl 2 278on 279.Xr wscons 4 280to be performed, and allows the 281.Dv NFSSVC_BIOD 282mode of the 283.Xr nfssvc 2 284system call to be used for compatibility with the deprecated nfsiod program. 285.It Cd options COMPAT_15 286Enable binary compatibility with 287.Nx 1.5 . 288Since there were no API changes from 289.Nx 1.5 290and 291.Nx 1.6 , 292this option does nothing. 293.It Cd options COMPAT_16 294Enable binary compatibility with 295.Nx 1.6 . 296This allows the use of old signal trampoline code which has been deprecated 297with the addition of 298.Xr siginfo 2 . 299.It Cd options COMPAT_20 300Enable binary compatibility with 301.Nx 2.0 . 302This allows the use of old syscalls for 303.Fn statfs , 304.Fn fstatfs , 305.Fn getfsstat 306and 307.Fn fhstatfs , 308which have been deprecated with the addition of the 309.Xr statvfs 2 , 310.Xr fstatvfs 2 , 311.Xr getvfsstat 2 312and 313.Xr fhstatvfs 2 314system calls. 315.It Cd options COMPAT_30 316Enable binary compatibility with 317.Nx 3.0 . 318See 319.Xr compat_30 8 320for details about the changes made after the 321.Nx 3.0 322release. 323.It Cd options COMPAT_43 324Enables compatibility with 325.Bx 4.3 . 326This adds an old syscall for 327.Xr lseek 2 . 328It also adds the ioctls for 329.Dv TIOCGETP 330and 331.Dv TIOCSETP . 332The return values for 333.Xr getpid 2 , 334.Xr getgid 2 , 335and 336.Xr getuid 2 337syscalls are modified as well, to return the parent's PID and 338UID as well as the current process's. 339It also enables the deprecated 340.Dv NTTYDISC 341terminal line discipline. 342It also provides backwards compatibility with 343.Dq old 344SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 345binary compatibility with code written before the introduction of the 346sa_len field in sockaddrs. 347It also enables 348support for some older pre 349.Bx 4.4 350socket calls. 351.It Cd options COMPAT_BSDPTY 352This option is currently on by default and enables the pty multiplexer 353.Xr ptm 4 354and 355.Xr ptmx 4 356to find and use ptys named 357.Pa /dev/ptyXX 358(master) and 359.Pa /dev/ttyXX 360(slave). 361Eventually this option will become optional as ptyfs based pseudo-ttys become 362the default, see 363.Xr mount_ptyfs 8 . 364.It Cd options COMPAT_SVR4 365On those architectures that support it, this enables binary 366compatibility with 367.At V.4 368applications built for the same architecture. 369This currently includes the i386, m68k, and sparc ports. 370.It Cd options COMPAT_LINUX 371On those architectures that support it, this enables binary 372compatibility with Linux ELF and 373.Xr a.out 5 374applications built for the same architecture. 375This currently includes the alpha, arm, i386, m68k, mips, powerpc and 376x86_64 ports. 377.It Cd options COMPAT_LINUX32 378On those 64 bit architectures that support it, this enables binary 379compatibility with 32 bit Linux binaries. 380For now this is limited to running i386 ELF Linux binaries on amd64. 381.It Cd options COMPAT_SUNOS 382On those architectures that support it, this enables binary 383compatibility with 384.Tn SunOS 4.1 385applications built for the same architecture. 386This currently includes the sparc, sparc64 and most or all m68k ports. 387Note that the sparc64 requires the 388.Em COMPAT_NETBSD32 389option for 64-bit kernels, in addition to this option. 390.It Cd options COMPAT_ULTRIX 391On those architectures that support it, this enables binary 392compatibility with 393.Tn ULTRIX 394applications built for the same architecture. 395This currently is limited to the pmax. 396The functionality of this option is unknown. 397.It Cd options COMPAT_DARWIN 398On those architectures that support it, this enables binary compatibility with 399.Tn Darwin 400applications built for the same architecture. 401This feature is highly experimental, it requires COMPAT_MACH and 402EXEC_MACHO and it is currently limited to i386 and powerpc ports of 403.Nx . 404.It Cd options COMPAT_FREEBSD 405On those architectures that support it, this enables binary 406compatibility with 407.Fx 408applications built for the same architecture. 409At the moment this is limited to the i386 port. 410.It Cd options COMPAT_IBCS2 411On those architectures that support it, this enables binary 412compatibility with iBCS2 or SVR3 applications built for the same architecture. 413This is currently limited to the i386 and vax ports. 414.It Cd options COMPAT_IRIX 415On those architectures that support it, this enables binary 416compatibility with IRIX o32 binaries built for the same architecture. 417This feature is experimental, and it is currently limited to 418the sgimips port. 419.It Cd options COMPAT_MACH 420On those architectures that support it, this enables the emulation of 421Mach kernel traps for binaries built for the same architecture. 422This feature is highly experimental and it is currently 423limited to the i386 and powerpc ports of 424.Nx . 425.It Cd options COMPAT_OSF1 426On those architectures that support it, this enables binary 427compatibility with 428.Tn Digital 429.Ux 430.Po 431formerly 432.Tn OSF/1 433.Pc 434applications built for the same architecture. 435This is currently limited to the alpha port. 436.It Cd options COMPAT_NOMID 437Enable compatibility with 438.Xr a.out 5 439executables that lack a machine ID. 440This includes 441.Nx 0.8 Ns 's 442ZMAGIC format, and 386BSD and BSDI's 443QMAGIC, NMAGIC, and OMAGIC 444.Xr a.out 5 445formats. 446.It Cd options COMPAT_NETBSD32 447On those architectures that support it, this enables binary 448compatibility with 32-bit applications built for the same architecture. 449This is currently limited to the amd64 and sparc64 ports, and only 450applicable for 64-bit kernels. 451.It Cd options COMPAT_SVR4_32 452On those architectures that support it, this enables binary 453compatibility with 32-bit SVR4 applications built for the same architecture. 454This is currently limited to the sparc64 port, and only applicable for 45564-bit kernels. 456.It Cd options COMPAT_AOUT_M68K 457On m68k architectures which have switched to ELF, 458this enables binary compatibility with 459.Nx Ns Tn /m68k 460.Xr a.out 5 461executables on 462.Nx Ns Tn /m68k 463ELF kernels. 464This handles alignment incompatibility of m68k ABI between 465a.out and ELF which causes the structure padding differences. 466Currently only some system calls which use 467.Va struct stat 468are adjusted and some binaries which use 469.Xr sysctl 3 470to retrieve network details would not work properly. 471.It Cd options EXEC_MACHO 472On those architectures that support it, this adds support for running 473Mach-O executables. 474This is currently limited to the i386 and powerpc ports of 475.Nx . 476.It Cd options EXEC_ELF_NOTELESS 477Run unidentified ELF binaries as 478.Nx 479binaries. 480This might be needed for very old 481.Nx 482ELF binaries on some archs. 483These old binaries didn't contain an appropriate 484.Li .note.netbsd.ident 485section, and thus can't be identified by the kernel as 486.Nx 487binaries otherwise. 488Beware - if this option is on, the kernel would run 489.Em any 490unknown ELF binaries as if they were 491.Nx 492binaries. 493.It Cd options P1003_1B_SEMAPHORE 494Includes kernel support for the standard C library 495.Pq libc 496functions that implement semaphores as specified in 497.St -p1003.1-96 . 498.El 499.Ss Debugging Options 500.Bl -ohang 501.It Cd options DDB 502Compiles in a kernel debugger for diagnosing kernel problems. 503See 504.Xr ddb 4 505for details. 506.Em NOTE : 507not available on all architectures. 508.It Cd options DDB_FROMCONSOLE=integer 509If set to non-zero, DDB may be entered by sending a break on a serial 510console or by a special key sequence on a graphics console. 511A value of "0" ignores console breaks or key sequences. 512If not explicitly specified, the default value is "1". 513Note that this sets the value of the 514.Em ddb.fromconsole 515.Xr sysctl 3 516variable which may be changed at run time -- see 517.Xr sysctl 8 518for details. 519.It Cd options DDB_HISTORY_SIZE=integer 520If this is non-zero, enable history editing in the kernel debugger 521and set the size of the history to this value. 522.It Cd options DDB_ONPANIC 523The default if not specified is 524.Dq 1 525- just enter into DDB. 526If set to 527.Dq 2 528the kernel will 529attempt to print out a stack trace before entering into DDB. 530If set to 531.Dq 0 532the kernel will attempt to print out a stack trace 533and reboot the system. 534If set to 535.Dq -1 536then neither a stack trace is printed or DDB entered - 537it is as if DDB were not compiled into the kernel. 538Note that this sets the value of the 539.Em ddb.onpanic 540.Xr sysctl 3 541variable which may be changed at run time -- see 542.Xr sysctl 8 543for details. 544.It Cd options DDB_COMMANDONENTER=string 545This option specify commands which will be executed on each entry to DDB. 546This sets the default value of the 547.Em ddb.commandonenter 548.Xr sysctl 3 549variable which may be changed at run time. 550.It Cd options DDB_BREAK_CHAR=integer 551This option overrides using break to enter the kernel debugger 552on the serial console. 553The value given is the ASCII value to be used instead. 554This is currently only supported by the com driver. 555.It Cd options DDB_VERBOSE_HELP 556This option adds more verbose descriptions to the 557.Em help 558command. 559.It Cd options KGDB 560Compiles in a remote kernel debugger stub for diagnosing kernel problems 561using the 562.Dq remote target 563feature of gdb. 564See 565.Xr gdb 1 566for details. 567.Em NOTE : 568not available on all architectures. 569.It Cd options KGDB_DEV 570Device number 571.Po 572as a 573.Dv dev_t 574.Pc 575of kgdb device. 576.It Cd options KGDB_DEVADDR 577Memory address of kgdb device. 578.It Cd options KGDB_DEVMODE 579Permissions of kgdb device. 580.It Cd options KGDB_DEVNAME 581Device name of kgdb device. 582.It Cd options KGDB_DEVRATE 583Baud rate of kgdb device. 584.It Cd makeoptions DEBUG="-g" 585The 586.Fl g 587flag causes 588.Pa netbsd.gdb 589to be built in addition to 590.Pa netbsd . 591.Pa netbsd.gdb 592is useful for debugging kernel crash dumps with gdb. 593See 594.Xr gdb 1 595for details. 596This also turns on 597.Em options DEBUG 598(which see). 599.It Cd options DEBUG 600Turns on miscellaneous kernel debugging. 601Since options are turned into preprocessor defines (see above), 602.Em options DEBUG 603is equivalent to doing a 604.Em #define DEBUG 605throughout the kernel. 606Much of the kernel has 607.Em #ifdef DEBUG 608conditionalized debugging code. 609Note that many parts of the kernel (typically device drivers) include their own 610.Em #ifdef XXX_DEBUG 611conditionals instead. 612This option also turns on certain other options, 613which may decrease system performance. 614.It Cd options DIAGNOSTIC 615Adds code to the kernel that does internal consistency checks. 616This code will cause the kernel to panic if corruption of internal data 617structures is detected. 618These checks can decrease performance up to 15%. 619.It Cd options KSTACK_CHECK_MAGIC 620Check kernel stack usage and panic if stack overflow is detected. 621This check is performance sensitive because it scans stack on each context 622switch. 623.It Cd options KTRACE 624Add hooks for the system call tracing facility, which allows users to 625watch the system call invocation behavior of processes. 626See 627.Xr ktrace 1 628for details. 629.It Cd options MSGBUFSIZE=integer 630This option sets the size of the kernel message buffer. 631This buffer holds the kernel output of 632.Fn printf 633when not (yet) read by 634.Xr syslogd 8 . 635This is particularly useful when the system has crashed and you wish to lookup 636the kernel output from just before the crash. 637Also, since the autoconfig output becomes more and more verbose, 638it sometimes happens that the message buffer overflows before 639.Xr syslogd 8 640was able to read it. 641Note that not all systems are capable of obtaining a variable sized message 642buffer. 643There are also some systems on which memory contents are not preserved 644across reboots. 645.It Cd options MALLOCLOG 646Enables an event log for 647.Xr malloc 9 . 648Useful for tracking down 649.Dq Data modified on freelist 650and 651.Dq multiple free 652problems. 653.It Cd options MALLOCLOGSIZE=integer 654Defines the number of entries in the malloc log. 655Default is 100000 entries. 656.It Cd options UVMHIST 657Enables the UVM history logs, which create in-memory traces of 658various UVM activities. 659These logs can be displayed be calling 660.Fn uvmhist_dump 661or 662.Fn uvm_hist 663with appropriate arguments from DDB. 664See the kernel source file sys/uvm/uvm_stat.c for details. 665.It Cd options UVMHIST_PRINT 666Prints the UVM history logs on the system console as entries are added. 667Note that the output is 668.Em extremely 669voluminous, so this option is really only useful for debugging 670the very earliest parts of kernel initialization. 671.El 672.Ss File Systems 673.Bl -ohang 674.It Cd file-system FFS 675Includes code implementing the Berkeley Fast File System 676.Po Em FFS Pc . 677Most machines need this if they are not running diskless. 678.It Cd file-system EXT2FS 679Includes code implementing the Second Extended File System 680.Po Em EXT2FS Pc , 681revision 0 and revision 1 with the 682.Em filetype 683and 684.Em sparse_super 685options. 686This is the most commonly used file system on the Linux operating system, 687and is provided here for compatibility. 688Some of the specific features of 689.Em EXT2FS 690like the "behavior on errors" are not implemented. 691This file system can't be used with UID or GID greater than 65535. 692See 693.Xr mount_ext2fs 8 694for details. 695.It Cd file-system LFS 696.Bq Em EXPERIMENTAL 697Include the Log-structured File System 698.Po Em LFS Pc . 699See 700.Xr mount_lfs 8 701and 702.Xr newfs_lfs 8 703for details. 704.It Cd file-system MFS 705Include the Memory File System 706.Po Em MFS Pc . 707This file system stores files in swappable memory, and produces 708notable performance improvements when it is used as the file store 709for 710.Pa /tmp 711and similar file systems. 712See 713.Xr mount_mfs 8 714for details. 715.It Cd file-system NFS 716Include the client side of the Network File System 717.Pq Tn NFS 718remote file sharing protocol. 719Although the bulk of the code implementing 720.Tn NFS 721is kernel based, several user level daemons are needed for it to work. 722See 723.Xr mount_nfs 8 724for details. 725.It Cd file-system CD9660 726Includes code for the 727.Tn ISO 7289660 + Rock Ridge file system, which is the standard file system on many 729.Tn CD-ROM 730discs. 731Useful primarily if you have a 732.Tn CD-ROM 733drive. 734See 735.Xr mount_cd9660 8 736for details. 737.It Cd file-system MSDOSFS 738Includes the 739.Tn MS-DOS 740FAT file system, which is reportedly still used 741by unfortunate people who have not heard about 742.Nx . 743Also implements the 744.Tn Windows 95 745extensions to the same, which permit the use of longer, mixed case 746file names. 747See 748.Xr mount_msdos 8 749and 750.Xr fsck_msdos 8 751for details. 752.It Cd file-system NTFS 753.Bq Em EXPERIMENTAL 754Includes code for the 755.Tn Microsoft Windows NT 756file system. 757See 758.Xr mount_ntfs 8 759for details. 760.It Cd file-system FDESC 761Includes code for a file system, conventionally mounted on 762.Pa /dev/fd , 763which permits access to the per-process file descriptor space via 764special files in the file system. 765See 766.Xr mount_fdesc 8 767for details. 768Note that this facility is redundant, and thus unneeded on most 769.Nx 770systems, since the 771.Xr fd 4 772pseudo-device driver already provides identical functionality. 773On most 774.Nx 775systems, instances of 776.Xr fd 4 777are mknoded under 778.Pa /dev/fd/ 779and on 780.Pa /dev/stdin , 781.Pa /dev/stdout , 782and 783.Pa /dev/stderr . 784.It Cd file-system KERNFS 785Includes code which permits the mounting of a special file system 786(normally mounted on 787.Pa /kern ) 788in which files representing various kernel variables and parameters 789may be found. 790See 791.Xr mount_kernfs 8 792for details. 793.It Cd file-system NULLFS 794Includes code for a loopback file system. 795This permits portions of the file hierarchy to be re-mounted in other places. 796The code really exists to provide an example of a stackable file system layer. 797See 798.Xr mount_null 8 799for details. 800.It Cd file-system OVERLAY 801Includes code for a file system filter. 802This permits the overlay file system to intercept all access to an underlying 803file system. 804This file system is intended to serve as an example of a stacking file 805system which has a need to interpose itself between an underlying file 806system and all other access. 807See 808.Xr mount_overlay 8 809for details. 810.It Cd file-system PORTAL 811.Bq Em EXPERIMENTAL 812Includes the portal file system. 813This permits interesting tricks like opening 814.Tn TCP 815sockets by opening files in the file system. 816The portal file system is conventionally mounted on 817.Pa /p 818and is partially implemented by a special daemon. 819See 820.Xr mount_portal 8 821for details. 822.It Cd file-system PROCFS 823Includes code for a special file system (conventionally mounted on 824.Pa /proc ) 825in which the process space becomes visible in the file system. 826Among 827other things, the memory spaces of processes running on the system are 828visible as files, and signals may be sent to processes by writing to 829.Pa ctl 830files in the procfs namespace. 831See 832.Xr mount_procfs 8 833for details. 834.It Cd file-system UDF 835.Bq Em EXPERIMENTAL 836Includes code for the UDF file system commonly found on CD and DVD 837media but also more and more on USB sticks. 838Useful primarily if you have a CD or a DVD drive, be it a read-only 839or a rewritable device. 840Currently only supports read-access. 841See 842.Xr mount_udf 8 843for details. 844.It Cd file-system UMAPFS 845Includes a loopback file system in which user and group IDs may be 846remapped -- this can be useful when mounting alien file systems with 847different UIDs and GIDs than the local system. 848See 849.Xr mount_umap 8 850for details. 851.It Cd file-system UNION 852.Bq Em EXPERIMENTAL 853Includes code for the union file system, which permits directories to 854be mounted on top of each other in such a way that both file systems 855remain visible -- this permits tricks like allowing writing (and the 856deleting of files) on a read-only file system like a 857.Tn CD-ROM 858by mounting a local writable file system on top of the read-only file system. 859See 860.Xr mount_union 8 861for details. 862.It Cd file-system CODA 863.Bq Em EXPERIMENTAL 864Includes code for the Coda file system. 865Coda is a distributed file system like NFS and AFS. 866It is freely available, like NFS, but it functions much like AFS in being a 867.Dq stateful 868file system. 869Both Coda and AFS cache files on your local machine to improve performance. 870Then Coda goes a step further than AFS by letting you access the cached 871files when there is no available network, viz. disconnected laptops and 872network outages. 873In Coda, both the client and server are outside the kernel which makes 874them easier to experiment with. 875Coda is available for several UNIX and non-UNIX platforms. 876See http://www.coda.cs.cmu.edu for more details. 877.Em NOTE : 878You also need to enable the pseudo-device, vcoda, for the Coda 879file system to work. 880.It Cd file-system SMBFS 881.Bq Em EXPERIMENTAL 882Includes code for the SMB/CIFS file system. 883See 884.Xr mount_smbfs 8 885for details. 886.Em NOTE : 887You also need to enable the pseudo-device, nsmb, for the SMB 888file system to work. 889.It Cd file-system PTYFS 890.Bq Em EXPERIMENTAL 891Includes code for a special file system (normally mounted on 892.Pa /dev/pts ) 893in which pseudo-terminal slave devices become visible in the file system. 894See 895.Xr mount_ptyfs 8 896for details. 897.It Cd file-system TMPFS 898Includes code for the efficient memory file system, normally used over 899.Pa /tmp . 900See 901.Xr mount_tmpfs 8 902for details. 903.It Cd file-system PUFFS 904.Bq Em EXPERIMENTAL 905Includes kernel support for the pass-to-userspace framework file system. 906It can be used to implement file system functionality in userspace. 907See 908.Xr puffs 3 909and 910.Xr puffs 4 911for more details. 912This option is required for sshfs: 913.Xr mount_psshfs 8 . 914.El 915.Ss File System Options 916.Bl -ohang 917.It Cd options MAGICLINKS 918Enables the expansion of special strings 919.Po 920beginning with 921.Dq @ 922.Pc 923when traversing symbolic links. 924See 925.Xr symlink 7 926for a list of supported strings. 927Note that this option only controls the enabling of this feature 928by the kernel at boot-up. 929This feature can still be manipulated with the 930.Xr sysctl 8 931command regardless of the setting of this option. 932.It Cd options NFSSERVER 933Include the server side of the 934.Em NFS 935(Network File System) remote file sharing protocol. 936Although the bulk of the code implementing 937.Em NFS 938is kernel based, several user level daemons are needed for it to 939work. 940See 941.Xr mountd 8 942and 943.Xr nfsd 8 944for details. 945.It Cd options QUOTA 946Enables kernel support for file system quotas. 947See 948.Xr quotaon 8 , 949.Xr edquota 8 , 950and 951.Xr quota 1 952for details. 953Note that quotas only work on 954.Dq ffs 955file systems, although 956.Xr rpc.rquotad 8 957permits them to be accessed over 958.Em NFS . 959.It Cd options FFS_EI 960Enable ``Endian-Independent'' FFS support. 961This allows a system to mount an FFS file system created for another 962architecture, at a small performance cost for all FFS file systems. 963See also 964.Xr newfs 8 , 965.Xr fsck_ffs 8 , 966.Xr dumpfs 8 967for file system byte order status and manipulation. 968.It Cd options FFS_NO_SNAPSHOT 969Disable the 970.Dq file system snapshot 971support in FFS file systems. 972Maybe useful for install media kernels, small memory systems and 973embedded systems which don't require the snapshot support. 974.It Cd options WAPBL 975Enable 976.Dq Write Ahead Physical Block Logging file system journaling . 977This provides rapid file system consistency checking after a system outage. 978It also provides better general use performance over regular FFS. 979See also 980.Xr wapbl 4 . 981.It Cd options NVNODE=integer 982This option sets the size of the cache used by the name-to-inode translation 983routines, (a.k.a. the 984.Fn namei 985cache, though called by many other names in the kernel source). 986By default, this cache has 987.Dv NPROC 988(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 989A reasonable way to derive a value of 990.Dv NVNODE , 991should you notice a large number of namei cache misses with a tool such as 992.Xr systat 1 , 993is to examine your system's current computed value with 994.Xr sysctl 8 , 995(which calls this parameter "kern.maxvnodes") and to increase this value 996until either the namei cache hit rate improves or it is determined that 997your system does not benefit substantially from an increase in the size of 998the namei cache. 999.It Cd options NAMECACHE_ENTER_REVERSE 1000Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1001as well as a normal one. 1002Normally, this is already done for directory vnodes, to speed up the getcwd 1003operation. 1004This option will cause longer hash chains in the reverse cache, and thus 1005slow down getcwd somewhat. 1006However, it does make vnode -\*[Gt] path translations possible in some cases. 1007For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1008required. 1009.It Cd options EXT2FS_SYSTEM_FLAGS 1010This option changes the behavior of the APPEND and IMMUTABLE flags 1011for a file on an 1012.Em EXT2FS 1013file system. 1014Without this option, the superuser or owner of the file can 1015set and clear them. 1016With this option, only the superuser can set them, and 1017they can't be cleared if the securelevel is greater than 0. 1018See also 1019.Xr chflags 1 1020and 1021.Xr secmodel_securelevel 9 . 1022.It Cd options NFS_BOOT_BOOTP 1023Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1024information if NFS is used to mount the root file system. 1025See 1026.Xr diskless 8 1027for details. 1028.It Cd options NFS_BOOT_DHCP 1029Same as 1030.Dq NFS_BOOT_BOOTP , 1031but use the DHCP extensions to the 1032BOOTP protocol (RFC 1541). 1033.It Cd options NFS_BOOT_BOOTP_REQFILE 1034Specifies the string sent in the bp_file field of the BOOTP / DHCP 1035request packet. 1036.It Cd options NFS_BOOT_BOOTPARAM 1037Enable use of the BOOTPARAM protocol, consisting of RARP and 1038BOOTPARAM RPC, to get configuration information if NFS 1039is used to mount the root file system. 1040See 1041.Xr diskless 8 1042for details. 1043.It Cd options NFS_BOOT_RWSIZE=value 1044Set the initial NFS read and write sizes for diskless-boot requests. 1045The normal default is 8Kbytes. 1046This option provides a way to lower the value (e.g., to 1024 bytes) 1047as a workaround for buggy network interface cards or boot PROMs. 1048Once booted, the read and write request sizes can be increased by 1049remounting the file system. 1050See 1051.Xr mount_nfs 8 1052for details. 1053.It Cd options NFS_V2_ONLY 1054Reduce the size of the NFS client code by omitting code that's only required 1055for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1056servers. 1057.It Cd options SOFTDEP 1058Enable kernel support for soft-dependencies in FFS file systems. 1059Softdep improves write performance by aggregating and properly 1060ordering disk metadata writes, achieving near-asynchronous write 1061performance while maintaining the file system consistency of 1062synchronous writes. 1063Soft-dependencies are enabled on a per-mount basis. 1064See 1065.Xr mount 8 1066for details. 1067.It Cd options UFS_DIRHASH 1068Increase lookup performance by maintaining in-core hash tables 1069for large directories. 1070.El 1071.Ss Buffer queue strategy options 1072The following options enable alternative buffer queue strategies. 1073.Bl -ohang 1074.It Cd options BUFQ_READPRIO 1075Enable experimental buffer queue strategy for disk I/O. 1076In the default strategy, outstanding disk requests are ordered by 1077sector number and sent to the disk, regardless of whether the 1078operation is a read or write; this option gives priority to issuing 1079read requests over write requests. 1080Although requests may therefore be issued out of sector-order, causing 1081more seeks and thus lower overall throughput, interactive system 1082responsiveness under heavy disk I/O load may be improved, as processes 1083blocking on disk reads are serviced sooner (file writes typically 1084don't cause applications to block). 1085The performance effect varies greatly depending on the hardware, drive 1086firmware, file system configuration, workload, and desired performance 1087trade-off. 1088Systems using drive write-cache (most modern IDE disks, by default) 1089are unlikely to benefit and may well suffer; such disks acknowledge 1090writes very quickly, and optimize them internally according to 1091physical layout. 1092Giving these disks as many requests to work with as possible (the 1093standard strategy) will typically produce the best results, especially 1094if the drive has a large cache; the drive will silently complete 1095writes from cache as it seeks for reads. 1096Disks that support a large number of concurrent tagged requests (SCSI 1097disks and many hardware RAID controllers) expose this internal 1098scheduling with tagged responses, and don't block for reads; such 1099disks may not see a noticeable difference with either strategy. 1100However, if IDE disks are run with write-cache disabled for safety, 1101writes are not acknowledged until actually completed, and only one 1102request can be outstanding; a large number of small writes in one 1103locality can keep the disk busy, starving reads elsewhere on the disk. 1104Such systems are likely to see the most benefit from this option. 1105Finally, the performance interaction of this option with ffs soft 1106dependencies can be subtle, as that mechanism can drastically alter 1107the workload for file system metadata writes. 1108.It Cd options BUFQ_PRIOCSCAN 1109Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1110.It Cd options NEW_BUFQ_STRATEGY 1111Synonym of 1112.Em BUFQ_READPRIO . 1113.El 1114.Ss Miscellaneous Options 1115.Bl -ohang 1116.It Cd options MEMORY_DISK_DYNAMIC 1117This option makes the 1118.Xr md 4 1119.Tn RAM 1120disk size dynamically sized. 1121It is incompatible with 1122.Xr mdsetimage 8 . 1123.It Cd options MEMORY_DISK_HOOKS 1124This option allows for some machine dependent functions to be called when 1125the 1126.Xr md 4 1127.Tn RAM 1128disk driver is configured. 1129This can result in automatically loading a 1130.Tn RAM 1131disk from floppy on open (among other things). 1132.It Cd options MEMORY_DISK_IS_ROOT 1133Forces the 1134.Xr md 4 1135.Tn RAM 1136disk to be the root device. 1137This can only be overridden when 1138the kernel is booted in the 'ask-for-root' mode. 1139.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1140Allocates the given number of 512 byte blocks as memory for the 1141.Xr md 4 1142.Tn RAM 1143disk, to be populated with 1144.Xr mdsetimage 8 . 1145.It Cd options MEMORY_DISK_SERVER=0 1146Do not include the interface to a userland memory disk server process. 1147Per default, this option is set to 1, including the support code. 1148Useful for install media kernels. 1149.It Cd options MEMORY_DISK_RBFLAGS=value 1150This option sets the 1151.Xr reboot 2 1152flags used when booting with a memory disk as root file system. 1153Possible values include 1154.Dv RB_AUTOBOOT 1155(boot in the usual fashion - default value), and 1156.Dv RB_SINGLE 1157(boot in single-user mode). 1158.It Cd options MODULAR 1159Enables the framework for kernel modules. 1160.It Cd options VND_COMPRESSION 1161Enables the 1162.Xr vnd 4 1163driver to also handle compressed images. 1164See 1165.Xr vndcompress 1 , 1166.Xr vnd 4 1167and 1168.Xr vnconfig 8 1169for more information. 1170.It Cd options TFTPROOT 1171Download the root memory disk through TFTP at root mount time. 1172This enables the use of a root 1173.Tn RAM 1174disk without requiring it to be embedded in the kernel using 1175.Xr mdsetimage 8 . 1176The 1177.Tn RAM 1178disk name is obtained using DHCP's filename parameter. 1179This option requires 1180.Em MEMORY_DISK_HOOKS , 1181.Em MEMORY_DISK_DYNAMIC , 1182and 1183.Em MEMORY_DISK_IS_ROOT . 1184It is incompatible with 1185.Em MEMORY_DISK_ROOT_SIZE . 1186.It Cd options MALLOC_NOINLINE 1187Time critical fixed size memory allocation is performed with 1188.Fn MALLOC 1189and 1190.Fn FREE . 1191Normally these expand to inline code, but with 1192.Em MALLOC_NOINLINE 1193these call the normal 1194.Fn malloc 1195and 1196.Fn free 1197functions. 1198Useful for install media kernels, small memory systems and embedded systems. 1199.It Cd options HZ=integer 1200On ports that support it, set the system clock frequency (see 1201.Xr hz 9 ) 1202to the supplied value. 1203Handle with care. 1204.It Cd options NTP 1205Turns on in-kernel precision timekeeping support used by software 1206implementing 1207.Em NTP 1208(Network Time Protocol, RFC 1305). 1209The 1210.Em NTP 1211option adds an in-kernel Phase-Locked Loop (PLL) for normal 1212.Em NTP 1213operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1214operation. 1215.Xr ntpd 8 1216will employ a user-level PLL when kernel support is unavailable, 1217but the in-kernel version has lower latency and more precision, and 1218so typically keeps much better time. 1219The interface to the kernel 1220.Em NTP 1221support is provided by the 1222.Xr ntp_adjtime 2 1223and 1224.Xr ntp_gettime 2 1225system calls, which are intended for use by 1226.Xr ntpd 8 1227and are enabled by the option. 1228On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1229is not an integer, the 1230.Em NTP 1231option also enables extended-precision arithmetic to keep track of 1232fractional clock ticks at NTP time-format precision. 1233.It Cd options PPS_SYNC 1234This option enables a kernel serial line discipline for receiving time 1235phase signals from an external reference clock such as a radio clock. 1236(The 1237.Em NTP 1238option (which see) must be on if the 1239.Em PPS_SYNC 1240option is used.) 1241Some reference clocks generate a Pulse Per Second (PPS) signal in 1242phase with their time source. 1243The 1244.Em PPS 1245line discipline receives this signal on either the data leads 1246or the DCD control lead of a serial port. 1247.Em NTP 1248uses the PPS signal to discipline the local clock oscillator to a high 1249degree of precision (typically less than 50 microseconds in time and 12500.1 ppm in accuracy). 1251.Em PPS 1252can also generate a serial output pulse when the system receives a PPS 1253interrupt. 1254This can be used to measure the system interrupt latency and thus calibrate 1255.Em NTP 1256to account for it. 1257Using 1258.Em PPS 1259usually requires a 1260gadget box 1261to convert from TTL to RS-232 signal levels. 1262The gadget box and PPS are described in more detail in the HTML documentation 1263for 1264.Xr ntpd 8 1265in 1266.Pa /usr/share/doc/html/ntp . 1267.It Cd options SETUIDSCRIPTS 1268Allows scripts with the setuid bit set to execute as the effective 1269user rather than the real user, just like binary executables. 1270.Pp 1271.Em NOTE : 1272Using this option will also enable 1273.Em options FDSCRIPTS 1274.It Cd options FDSCRIPTS 1275Allows execution of scripts with the execute bit set, but not the 1276read bit, by opening the file and passing the file descriptor to 1277the shell, rather than the filename. 1278.Pp 1279.Em NOTE : 1280Execute only (non-readable) scripts will have 1281.Va argv[0] 1282set to 1283.Pa /dev/fd/* . 1284What this option allows as far as security is 1285concerned, is the ability to safely ensure that the correct script 1286is run by the interpreter, as it is passed as an already open file. 1287.It Cd options PUCCN 1288Enables treating serial ports found on PCI boards 1289.Xr puc 4 1290as potential console devices. 1291The method for choosing such a console device is port dependent. 1292.It Cd options RTC_OFFSET=integer 1293The kernel (and typically the hardware battery backed-up clock on 1294those machines that have one) keeps time in 1295.Em UTC 1296(Universal Coordinated Time, once known as 1297.Em GMT , 1298or Greenwich Mean Time) 1299and not in the time of the local time zone. 1300The 1301.Em RTC_OFFSET 1302option is used on some ports (such as the i386) to tell the kernel 1303that the hardware clock is offset from 1304.Em UTC 1305by the specified number of minutes. 1306This is typically used when a machine boots several operating 1307systems and one of them wants the hardware clock to run in the 1308local time zone and not in 1309.Em UTC , 1310e.g. 1311.Em RTC_OFFSET=300 1312means 1313the hardware clock is set to US Eastern Time (300 minutes behind 1314.Em UTC ) , 1315and not 1316.Em UTC . 1317(Note: 1318.Em RTC_OFFSET 1319is used to initialize a kernel variable named 1320.Va rtc_offset 1321which is the source actually used to determine the clock offset, and 1322which may be accessed via the kern.rtc_offset sysctl variable. 1323See 1324.Xr sysctl 8 1325and 1326.Xr sysctl 3 1327for details. 1328Since the kernel clock is initialized from the hardware clock very 1329early in the boot process, it is not possible to meaningfully change 1330.Va rtc_offset 1331in system initialization scripts. 1332Changing this value currently may only be done at kernel compile 1333time or by patching the kernel and rebooting). 1334.Pp 1335.Em NOTE : 1336Unfortunately, in many cases where the hardware clock 1337is kept in local time, it is adjusted for Daylight Savings 1338Time; this means that attempting to use 1339.Em RTC_OFFSET 1340to let 1341.Nx 1342coexist with such an operating system, like Windows, 1343would necessitate changing 1344.Em RTC_OFFSET 1345twice a year. 1346As such, this solution is imperfect. 1347.It Cd options KMEMSTATS 1348The kernel memory allocator, 1349.Xr malloc 9 , 1350will keep statistics on its performance if this option is enabled. 1351Unfortunately, this option therefore essentially disables the 1352.Fn MALLOC 1353and 1354.Fn FREE 1355forms of the memory allocator, which are used to enhance the performance 1356of certain critical sections of code in the kernel. 1357This option therefore can lead to a significant decrease in the 1358performance of certain code in the kernel if enabled. 1359Examples of such code include the 1360.Fn namei 1361routine, the 1362.Xr ccd 4 1363driver, 1364and much of the networking code. 1365.It Cd options MAXUPRC=integer 1366Sets the soft 1367.Dv RLIMIT_NPROC 1368resource limit, which specifies the maximum number of simultaneous 1369processes a user is permitted to run, for process 0; 1370this value is inherited by its child processes. 1371It defaults to 1372.Em CHILD_MAX , 1373which is currently defined to be 160. 1374Setting 1375.Em MAXUPRC 1376to a value less than 1377.Em CHILD_MAX 1378is not permitted, as this would result in a violation of the semantics of 1379.St -p1003.1-90 . 1380.It Cd options NOFILE=integer 1381Sets the soft 1382.Dv RLIMIT_NOFILE 1383resource limit, which specifies the maximum number of open 1384file descriptors for each process; 1385this value is inherited by its child processes. 1386It defaults to 1387.Em OPEN_MAX , 1388which is currently defined to be 64. 1389.It Cd options MAXFILES=integer 1390Sets the default value of the 1391.Em kern.maxfiles 1392sysctl variable, which indicates the maximum number of files that may 1393be open in the system. 1394.It Cd options DEFCORENAME=string 1395Sets the default value of the 1396.Em kern.defcorename 1397sysctl variable, otherwise it is set to 1398.Nm %n.core . 1399See 1400.Xr sysctl 8 1401and 1402.Xr sysctl 3 1403for details. 1404.It Cd options RASOPS_CLIPPING 1405Enables clipping within 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 RASOPS_SMALL 1413Removes optimized character writing code from the 1414.Nm rasops 1415raster-console output system. 1416.Em NOTE : 1417only available on architectures that use 1418.Nm rasops 1419for console output. 1420.It Cd options INCLUDE_CONFIG_FILE 1421Embeds the kernel config file used to define the kernel in the kernel 1422binary itself. 1423The embedded data also includes any files directly included by the config 1424file itself, e.g. 1425.Pa GENERIC.local 1426or 1427.Pa std.$MACHINE . 1428The embedded config file can be extracted from the resulting kernel with 1429.Xr config 1 1430.Fl x , 1431or by the following command: 1432.Bd -literal -offset indent 1433strings netbsd | sed -n 's/^_CFG_//p' | unvis 1434.Ed 1435.It Cd options INCLUDE_JUST_CONFIG 1436Similar to the above option, but includes just the actual config file, 1437not any included files. 1438.It Cd options PIPE_SOCKETPAIR 1439Use slower, but smaller socketpair(2)-based pipe implementation instead 1440of default faster, but bigger one. 1441Primarily useful for installation kernels. 1442.It Cd options USERCONF 1443Compiles in the in-kernel device configuration manager. 1444See 1445.Xr userconf 4 1446for details. 1447.It Cd options PERFCTRS 1448Compiles in kernel support for CPU performance-monitoring counters. 1449See 1450.Xr pmc 1 1451for details. 1452.Em NOTE : 1453not available on all architectures. 1454.It Cd options SYSCALL_STATS 1455Count the number of times each system call number is called. 1456The values can be read through the sysctl interface and displayed using 1457.Xr systat 1 . 1458.Em NOTE : 1459not yet available on all architectures. 1460.It Cd options SYSCALL_TIMES 1461Count the time spent (using 1462.Fn cpu_counter32 ) 1463in each system call. 1464.Em NOTE : 1465Using this option will also enable 1466.Cd options SYSCALL_STATS . 1467.It Cd options SYSCALL_TIMES_HASCOUNTER 1468Force use of 1469.Fn cpu_counter32 1470even if 1471.Fn cpu_hascounter 1472reports false. 1473Useful for systems where the cycle counter doesn't run at a constant rate 1474(e.g. Soekris boxes). 1475.It Cd options XSERVER 1476Compiles in kernel support for 1477.Tn X11 1478on architectures that still use (or can use) the legacy 1479.Em pccons 1480console drivers rather than 1481.Xr wscons 4 . 1482These include bebox, i386, shark. 1483.It Cd options XSERVER_DDB 1484A supplement to XSERVER that adds support for entering 1485.Xr ddb 4 1486while in 1487.Tn X11 . 1488.It Cd options FILEASSOC 1489Support for 1490.Xr fileassoc 9 . 1491.It Cd options FILEASSOC_NHOOKS=integer 1492Number of storage slots per file for 1493.Xr fileassoc 9 . 1494Default is 4. 1495.It Cd options I2C_SCAN 1496Scan each i2c bus to determine which addresses respond. 1497.Pp 1498.Em WARNING ! 1499Using this option can access some devices in such a 1500manner as to leave them in an unstable or unuseable state, and 1501can prevent those devices from being properly matched and/or 1502attached. 1503It can also lock up the entire i2c bus and even 1504prevent a machine from completing the boot process. 1505Don't use this option unless you know what you're doing and can 1506accept all sorts of unforseen consequences. 1507.El 1508.Ss Networking Options 1509.Bl -ohang 1510.It Cd options GATEWAY 1511Enables 1512.Em IPFORWARDING 1513(which see) 1514and (on most ports) increases the size of 1515.Em NMBCLUSTERS 1516(which see). 1517In general, 1518.Em GATEWAY 1519is used to indicate that a system should act as a router, and 1520.Em IPFORWARDING 1521is not invoked directly. 1522(Note that 1523.Em GATEWAY 1524has no impact on protocols other than 1525.Tn IP , 1526such as 1527.Tn CLNP 1528or 1529.Tn XNS ) . 1530.Em GATEWAY 1531option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1532.It Cd options ICMPPRINTFS 1533The 1534.Em ICMPPRINTFS 1535option will enable debugging information to be printed about 1536the 1537.Xr icmp 4 1538protocol. 1539.It Cd options IPFORWARDING=value 1540If 1541.Em value 1542is 1 this enables IP routing behavior. 1543If 1544.Em value 1545is 0 (the default), it disables it. 1546The 1547.Em GATEWAY 1548option sets this to 1 automatically. 1549With this option enabled, the machine will forward IP datagrams destined 1550for other machines between its interfaces. 1551Note that even without this option, the kernel will 1552still forward some packets (such as source routed packets) -- removing 1553.Em GATEWAY 1554and 1555.Em IPFORWARDING 1556is insufficient to stop all routing through a bastion host on a 1557firewall -- source routing is controlled independently. 1558To turn off source routing, use 1559.Em options IPFORWSRCRT=0 1560(which see). 1561Note that IP forwarding may be turned on and off independently of the 1562setting of the 1563.Em IPFORWARDING 1564option through the use of the 1565.Em net.inet.ip.forwarding 1566sysctl variable. 1567If 1568.Em net.inet.ip.forwarding 1569is 1, IP forwarding is on. 1570See 1571.Xr sysctl 8 1572and 1573.Xr sysctl 3 1574for details. 1575.It Cd options IPFORWSRCRT=value 1576If 1577.Em value 1578is set to zero, source routing of IP datagrams is turned off. 1579If 1580.Em value 1581is set to one (the default) or the option is absent, source routed IP 1582datagrams are forwarded by the machine. 1583Note that source routing of IP packets may be turned on and off 1584independently of the setting of the 1585.Em IPFORWSRCRT 1586option through the use of the 1587.Em net.inet.ip.forwsrcrt 1588sysctl variable. 1589If 1590.Em net.inet.ip.forwsrcrt 1591is 1, forwarding of source routed IP datagrams is on. 1592See 1593.Xr sysctl 8 1594and 1595.Xr sysctl 3 1596for details. 1597.It Cd options IFA_STATS 1598Tells the kernel to maintain per-address statistics on bytes sent 1599and received over (currently) Internet and AppleTalk addresses. 1600.\"This can be a fairly expensive operation, so you probably want to 1601.\"keep this disabled. 1602The option is not recommended as it degrades system stability. 1603.It Cd options IFQ_MAXLEN=value 1604Increases the allowed size of the network interface packet queues. 1605The default queue size is 50 packets, and you do not normally need 1606to increase it. 1607.It Cd options IPSELSRC 1608Includes support for source-address selection policies. 1609See 1610.Xr in_getifa 9 . 1611.It Cd options MROUTING 1612Includes support for IP multicast routers. 1613You certainly want 1614.Em INET 1615with this. 1616Multicast routing is controlled by the 1617.Xr mrouted 8 1618daemon. 1619See also option 1620.Cd PIM . 1621.It Cd options PIM 1622Includes support for Protocol Independent Multicast (PIM) routing. 1623You need 1624.Em MROUTING 1625and 1626.Em INET 1627with this. 1628Software using this can be found e.g. in 1629.Pa pkgsrc/net/xorp . 1630.It Cd options INET 1631Includes support for the 1632.Tn TCP/IP 1633protocol stack. 1634You almost certainly want this. 1635See 1636.Xr inet 4 1637for details. 1638.It Cd options INET6 1639Includes support for the 1640.Tn IPv6 1641protocol stack. 1642See 1643.Xr inet6 4 1644for details. 1645Unlike 1646.Em INET , 1647.Em INET6 1648enables multicast routing code as well. 1649This option requires 1650.Em INET 1651at this moment, but it should not. 1652.It Cd options ND6_DEBUG 1653The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1654for debugging IPv6 neighbor discovery protocol handling. 1655See 1656.Xr sysctl 3 1657for details. 1658.It Cd options IPSEC 1659Includes support for the 1660.Tn IPsec 1661protocol. 1662See 1663.Xr ipsec 4 1664for details. 1665.It Cd options IPSEC_DEBUG 1666Enables debugging code in 1667.Tn IPsec 1668stack. 1669See 1670.Xr ipsec 4 1671for details. 1672.It Cd options IPSEC_ESP 1673Includes support for 1674.Tn IPsec 1675.Tn ESP 1676protocol. 1677See 1678.Xr 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 NS 1839Include support for the 1840.Tn Xerox 1841.Tn XNS 1842protocol stack. 1843See 1844.Xr ns 4 1845for details. 1846.It Cd options ISO,TPIP 1847Include support for the ubiquitous 1848.Tn OSI 1849protocol stack. 1850See 1851.Xr iso 4 1852for details. 1853This option assumes 1854.Em INET . 1855.It Cd options EON 1856Include support for tunneling 1857.Tn OSI 1858protocols over 1859.Tn IP . 1860Known to be broken, or at least very fragile, and undocumented. 1861.It Cd options NETATALK 1862Include support for the 1863.Tn AppleTalk 1864protocol stack. 1865The kernel provides provision for the 1866.Em Datagram Delivery Protocol 1867(DDP), providing SOCK_DGRAM support and 1868.Tn AppleTalk 1869routing. 1870This stack is used by the 1871.Em NETATALK 1872package, which adds support for 1873.Tn AppleTalk 1874server services via user libraries and applications. 1875.It Cd options BLUETOOTH 1876Include support for the 1877.Tn Bluetooth 1878protocol stack. 1879See 1880.Xr bluetooth 4 1881for details. 1882.It Cd options IPNOPRIVPORTS 1883Normally, only root can bind a socket descriptor to a so-called 1884.Dq privileged 1885.Tn TCP 1886port, that is, a port number in the range 0-1023. 1887This option eliminates those checks from the kernel. 1888This can be useful if there is a desire to allow daemons without 1889privileges to bind those ports, e.g., on firewalls. 1890The security tradeoffs in doing this are subtle. 1891This option should only be used by experts. 1892.It Cd options TCP_COMPAT_42 1893.Tn TCP 1894bug compatibility with 1895.Bx 4.2 . 1896In 1897.Bx 4.2 , 1898.Tn TCP 1899sequence numbers were 32-bit signed values. 1900Modern implementations of TCP use unsigned values. 1901This option clamps the initial sequence number to start in 1902the range 2^31 rather than the full unsigned range of 2^32. 1903Also, under 1904.Bx 4.2 , 1905keepalive packets must contain at least one byte or else 1906the remote end would not respond. 1907.It Cd options TCP_DEBUG 1908Record the last 1909.Em TCP_NDEBUG 1910TCP packets with SO_DEBUG set, and decode to the console if 1911.Em tcpconsdebug 1912is set. 1913.It Cd options TCP_NDEBUG 1914Number of packets to record for 1915.Em TCP_DEBUG . 1916Defaults to 100. 1917.It Cd options TCP_SENDSPACE=value 1918.It Cd options TCP_RECVSPACE=value 1919These options set the max TCP window size to other sizes than the default. 1920The TCP window sizes can be altered via 1921.Xr sysctl 8 1922as well. 1923.It Cd options TCP_INIT_WIN=value 1924This option sets the initial TCP window size for non-local connections, 1925which is used when the transmission starts. 1926The default size is 1, but if the machine should act more aggressively, 1927the initial size can be set to some other value. 1928The initial TCP window size can be set via 1929.Xr sysctl 8 1930as well. 1931.It Cd options PFIL_HOOKS 1932This option turns on the packet filter interface hooks. 1933See 1934.Xr pfil 9 1935for details. 1936This option assumes 1937.Em INET . 1938.It Cd options IPFILTER_LOG 1939This option, in conjunction with 1940.Em pseudo-device ipfilter , 1941enables logging of IP packets using ip-filter. 1942.It Cd options IPFILTER_DEFAULT_BLOCK 1943This option sets the default policy of ip-filter. 1944If it is set, ip-filter will block packets by default. 1945.It Cd options BRIDGE_IPF 1946This option causes 1947.Em bridge 1948devices to use the IP and/or IPv6 filtering hooks, forming 1949a link-layer filter that uses protocol-layer rules. 1950This option assumes the presence of 1951.Em pseudo-device ipfilter . 1952.It Cd options MBUFTRACE 1953This option can help track down mbuf leaks. 1954When enabled, mbufs are tagged with the devices and protocols using them, 1955which slightly decreases network performance. 1956This additional information can be viewed with 1957.Xr netstat 1 : 1958.Dl Ic netstat Fl mssv 1959Not all devices or protocols support this option. 1960.El 1961.Ss Sysctl Related Options 1962.Bl -ohang 1963.It Cd options SYSCTL_DISALLOW_CREATE 1964Disallows the creation or deletion of nodes from the sysctl tree, as 1965well as the assigning of descriptions to nodes that lack them, by any 1966process. 1967These operations are still available to kernel sub-systems, including 1968loadable kernel modules. 1969.It Cd options SYSCTL_DISALLOW_KWRITE 1970Prevents processes from adding nodes to the sysctl tree that make 1971existing kernel memory areas writable. 1972Sections of kernel memory can still be read and new nodes that own 1973their own data may still be writable. 1974.It Cd options SYSCTL_DEBUG_SETUP 1975Causes the SYSCTL_SETUP routines to print a brief message when they 1976are invoked. 1977This is merely meant as an aid in determining the order in which 1978sections of the tree are created. 1979.It Cd options SYSCTL_DEBUG_CREATE 1980Prints a message each time 1981.Fn sysctl_create , 1982the function that adds nodes to the tree, is called. 1983.It Cd options SYSCTL_INCLUDE_DESCR 1984Causes the kernel to include short, human readable descriptions for 1985nodes in the sysctl tree. 1986The descriptions can be retrieved programmatically (see 1987.Xr sysctl 3 ) , 1988or by the sysctl binary itself (see 1989.Xr sysctl 8 ) . 1990The descriptions are meant to give an indication of the purpose and/or 1991effects of a given node's value, not replace the documentation for the 1992given subsystem as a whole. 1993.El 1994.Ss System V IPC Options 1995.Bl -ohang 1996.It Cd options SYSVMSG 1997Includes support for 1998.At V 1999style message queues. 2000See 2001.Xr msgctl 2 , 2002.Xr msgget 2 , 2003.Xr msgrcv 2 , 2004.Xr msgsnd 2 . 2005.It Cd options SYSVSEM 2006Includes support for 2007.At V 2008style semaphores. 2009See 2010.Xr semctl 2 , 2011.Xr semget 2 , 2012.Xr semop 2 . 2013.It Cd options SEMMNI=value 2014Sets the number of 2015.At V 2016style semaphore identifiers. 2017The GENERIC config file for your port will have the default. 2018.It Cd options SEMMNS=value 2019Sets the number of 2020.At V 2021style semaphores in the system. 2022The GENERIC config file for your port will have the default. 2023.It Cd options SEMUME=value 2024Sets the maximum number of undo entries per process for 2025.At V 2026style semaphores. 2027The GENERIC config file for your port will have the default. 2028.It Cd options SEMMNU=value 2029Sets the number of undo structures in the system for 2030.At V 2031style semaphores. 2032The GENERIC config file for your port will have the default. 2033.It Cd options SYSVSHM 2034Includes support for 2035.At V 2036style shared memory. 2037See 2038.Xr shmat 2 , 2039.Xr shmctl 2 , 2040.Xr shmdt 2 , 2041.Xr shmget 2 . 2042.It Cd options SHMMAXPGS=value 2043Sets the maximum number of 2044.At V 2045style shared memory pages that are available through the 2046.Xr shmget 2 2047system call. 2048Default value is 1024 on most ports. 2049See 2050.Pa /usr/include/machine/vmparam.h 2051for the default. 2052.El 2053.Ss VM Related Options 2054.Bl -ohang 2055.It Cd options NMBCLUSTERS=value 2056The number of mbuf clusters the kernel supports. 2057Mbuf clusters are MCLBYTES in size (usually 2k). 2058This is used to compute the size of the kernel VM map 2059.Em mb_map , 2060which maps mbuf clusters. 2061Default on most ports is 1024 (2048 with 2062.Dq options GATEWAY 2063). 2064See 2065.Pa /usr/include/machine/param.h 2066for exact default information. 2067Increase this value if you get 2068.Dq mclpool limit reached 2069messages. 2070.It Cd options NKMEMPAGES=value 2071.It Cd options NKMEMPAGES_MIN=value 2072.It Cd options NKMEMPAGES_MAX=value 2073Size of kernel VM map 2074.Em kmem_map , 2075in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2076from the 2077.Xr sysctl 8 2078variable 2079.Em hw.pagesize 2080). 2081This VM map is used to map the kernel malloc arena. 2082The kernel attempts to auto-size this map based on the amount of 2083physical memory in the system. 2084Platform-specific code may place bounds on this computed size, 2085which may be viewed with the 2086.Xr sysctl 8 2087variable 2088.Em vm.nkmempages . 2089See 2090.Pa /usr/include/machine/param.h 2091for the default upper and lower bounds. 2092The related options 2093.Sq NKMEMPAGES_MIN 2094and 2095.Sq NKMEMPAGES_MAX 2096allow the bounds to be overridden in the kernel configuration file. 2097These options are provided in the event the computed value is 2098insufficient resulting in an 2099.Dq out of space in kmem_map 2100panic. 2101.It Cd options SB_MAX=value 2102Sets the max size in bytes that a socket buffer is allowed to occupy. 2103The default is 256k, but sometimes it needs to be increased, for example 2104when using large TCP windows. 2105This option can be changed via 2106.Xr sysctl 8 2107as well. 2108.It Cd options SOMAXKVA=value 2109Sets the maximum size of kernel virtual memory that the socket buffers 2110are allowed to use. 2111The default is 16MB, but in situations where for example large TCP 2112windows are used this value must also be increased. 2113This option can be changed via 2114.Xr sysctl 8 2115as well. 2116.It Cd options BUFCACHE=value 2117Size of the buffer cache as a percentage of total available 2118.Tn RAM . 2119Ignored if BUFPAGES is also specified. 2120.It Cd options NBUF=value 2121Sets the number of buffer headers available, i.e., the number of 2122open files that may have a buffer cache entry. 2123Each buffer header 2124requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2125The default value is machine dependent, but is usually equal to the 2126value of BUFPAGES. 2127If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2128then NBUF may be reduced at run time so that the storage allocated 2129for buffer headers doesn't exceed that limit. 2130.It Cd options BUFPAGES=value 2131These options set the number of pages available for the buffer cache. 2132Their default value is a machine dependent value, often calculated as 2133between 5% and 10% of total available 2134.Tn RAM . 2135.It Cd options MAXTSIZ=bytes 2136Sets the maximum size limit of a process' text segment. 2137See 2138.Pa /usr/include/machine/vmparam.h 2139for the port-specific default. 2140.It Cd options DFLDSIZ=bytes 2141Sets the default size limit of a process' data segment, the value that 2142will be returned as the soft limit for 2143.Dv RLIMIT_DATA 2144(as returned by 2145.Xr getrlimit 2 ) . 2146See 2147.Pa /usr/include/machine/vmparam.h 2148for the port-specific default. 2149.It Cd options MAXDSIZ=bytes 2150Sets the maximum size limit of a process' data segment, the value that 2151will be returned as the hard limit for 2152.Dv RLIMIT_DATA 2153(as returned by 2154.Xr getrlimit 2 ) . 2155See 2156.Pa /usr/include/machine/vmparam.h 2157for the port-specific default. 2158.It Cd options DFLSSIZ=bytes 2159Sets the default size limit of a process' stack segment, the value that 2160will be returned as the soft limit for 2161.Dv RLIMIT_STACK 2162(as returned by 2163.Xr getrlimit 2 ) . 2164See 2165.Pa /usr/include/machine/vmparam.h 2166for the port-specific default. 2167.It Cd options MAXSSIZ=bytes 2168Sets the maximum size limit of a process' stack segment, the value that 2169will be returned as the hard limit for 2170.Dv RLIMIT_STACK 2171(as returned by 2172.Xr getrlimit 2 ) . 2173See 2174.Pa /usr/include/machine/vmparam.h 2175for the port-specific default. 2176.It Cd options DUMP_ON_PANIC=integer 2177Defaults to one. 2178If set to zero, the kernel will not dump to the dump device when 2179it panics, though dumps can still be forced via 2180.Xr ddb 4 2181with the 2182.Dq sync 2183command. 2184Note that this sets the value of the 2185.Em kern.dump_on_panic 2186.Xr sysctl 3 2187variable which may be changed at run time -- see 2188.Xr sysctl 8 2189for details. 2190.It Cd options USE_TOPDOWN_VM 2191User space memory allocations (as made by 2192.Xr mmap 2 ) 2193will be arranged in a 2194.Dq top down 2195fashion instead of the traditional 2196.Dq upwards from MAXDSIZ \+ vm_daddr 2197method. 2198This includes the placement of 2199.Xr ld.so 1 . 2200Arranging memory in this manner allows either (or both of) the heap or 2201.Xr mmap 2 2202allocated space to grow larger than traditionally possible. 2203This option is not available on all ports, but is instead expected to be 2204offered on a port-by-port basis, after which some ports will commit to 2205using it by default. 2206See the files 2207.Pa /usr/include/uvm/uvm_param.h 2208for some implementation details, and 2209.Pa /usr/include/machine/vmparam.h 2210for port specific details including availability. 2211.It Cd options VMSWAP 2212Enable paging device/file support. 2213This option is on by default. 2214.It Cd options PDPOLICY_CLOCKPRO 2215Use CLOCK-Pro, an alternative page replace policy. 2216.El 2217.Ss Security Options 2218.Bl -ohang 2219.It Cd options INSECURE 2220Hardwires the kernel security level at \-1. 2221This means that the system 2222always runs in secure level \-1 mode, even when running multiuser. 2223See the manual page for 2224.Xr init 8 2225for details on the implications of this. 2226The kernel secure level may manipulated by the superuser by altering the 2227.Em kern.securelevel 2228.Xr sysctl 3 2229variable (the secure level may only be lowered by a call from process ID 1, 2230i.e., 2231.Xr init 8 ) . 2232See also 2233.Xr secmodel_securelevel 9 , 2234.Xr sysctl 8 2235and 2236.Xr sysctl 3 . 2237.It Cd options VERIFIED_EXEC_FP_MD5 2238Enables support for MD5 hashes in Veriexec. 2239.It Cd options VERIFIED_EXEC_FP_SHA1 2240Enables support for SHA1 hashes in Veriexec. 2241.It Cd options VERIFIED_EXEC_FP_RMD160 2242Enables support for RMD160 hashes in Veriexec. 2243.It Cd options VERIFIED_EXEC_FP_SHA256 2244Enables support for SHA256 hashes in Veriexec. 2245.It Cd options VERIFIED_EXEC_FP_SHA384 2246Enables support for SHA384 hashes in Veriexec. 2247.It Cd options VERIFIED_EXEC_FP_SHA512 2248Enables support for SHA512 hashes in Veriexec. 2249.It Cd options PAX_MPROTECT=value 2250Enables PaX MPROTECT, 2251.Xr mprotect 2 2252restrictions from the PaX project. 2253.Pp 2254The 2255.Ar value 2256is the default value for the 2257.Em global 2258knob, see 2259.Xr sysctl 3 . 2260If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2261using 2262.Xr paxctl 8 . 2263If 1, PaX MPROTECT will be enabled for all programs. 2264Programs can be exempted using 2265.Xr paxctl 8 . 2266.Pp 2267See 2268.Xr security 8 2269for more details. 2270.It Cd options PAX_SEGVGUARD=value 2271Enables PaX Segvguard. 2272.Pp 2273The 2274.Ar value 2275is the default value for the 2276.Em global 2277knob, see 2278.Xr sysctl 3 . 2279If 0, PaX Segvguard will be enabled only if explicitly set on programs 2280using 2281.Xr paxctl 8 . 2282If 1, PaX Segvguard will be enabled to all programs, and exemption can 2283be done using 2284.Xr paxctl 8 . 2285.Pp 2286See 2287.Xr security 8 2288for more details. 2289.It Cd options PAX_ASLR=value 2290Enables PaX ASLR. 2291.Pp 2292The 2293.Ar value 2294is the default value for the 2295.Em global 2296knob, see 2297.Xr sysctl 3 . 2298If 0, PaX ASLR will be enabled only if explicitly set on programs 2299using 2300.Xr paxctl 8 . 2301If 1, PaX ASLR will be enabled to all programs, and exemption can 2302be done using 2303.Xr paxctl 8 . 2304.Pp 2305See 2306.Xr security 8 2307for more details. 2308.El 2309.Ss amiga-specific Options 2310.Bl -ohang 2311.It Cd options BB060STUPIDROM 2312When the bootloader (which passes 2313.Tn AmigaOS 2314.Tn ROM 2315information) claims we have a 68060 2316.Tn CPU 2317without 2318.Tn FPU , 2319go look into the Processor Configuration Register (PCR) to find out. 2320You need this with 2321.Tn Amiga 2322.Tn ROM Ns s 2323up to (at least) V40.xxx (OS3.1), 2324when you boot via the bootblocks and don't have a DraCo. 2325.It Cd options IOBZCLOCK=frequency 2326The IOBlix boards come with two different serial master clocks: older ones 2327use 24 MHz, newer ones use 22.1184 MHz. 2328The driver normally assumes the latter. 2329If your board uses 24 MHz, you can recompile your kernel with 2330options IOBZCLOCK=24000000 2331or patch the kernel variable 2332.Tn iobzclock 2333to the same value. 2334.It Cd options LIMITMEM=value 2335If there, limit the part of the first memory bank used by 2336.Nx 2337to value megabytes. 2338Default is unlimited. 2339.It Cd options NKPTADD=addvalue 2340.It Cd options NKPTADDSHIFT=shiftvalue 2341The 2342.Tn CPU 2343specific 2344.Tn MMU 2345table for the kernel is pre-allocated at kernel startup time. 2346Part of it is scaled with 2347.Va maxproc , 2348to have enough room to hold the user program 2349.Tn MMU 2350tables; the second part is a fixed amount for the kernel itself. 2351.Pp 2352The third part accounts for the size of the file buffer cache. 2353Its size is either 2354.Dv NKPTADD 2355pages (if defined) or memory size in bytes divided by two to 2356the power of 2357.Dv NKPTADDSHIFT . 2358The default is undefined 2359.Dv NKPTADD 2360and 2361.Dv NKPTADDSHIFT=24 , 2362allowing for 16 buffers per megabyte of main memory (while 2363a GENERIC kernel allocates about half of that). 2364When you get "can't get KPT page" panics, you should increase 2365.Dv NKPTADD 2366(if defined), or decrease 2367.Dv NKPTADDSHIFT 2368by one. 2369.It Cd options P5PPC68KBOARD 2370Add special support for Phase5 mixed 68k+PPC boards. 2371Currently, this only affects rebooting from 2372.Nx 2373and is only needed on 68040+PPC, not on 237468060+PPC; without this, affected machines will hang after 2375.Nx 2376has shut 2377down and will only restart after a keyboard reset or a power cycle. 2378.El 2379.Ss arm32-specific Options 2380.Bl -ohang 2381.It Cd options FRENCH_KBD 2382Include translation for French keyboards when using 2383.Em pccons 2384on a Shark. 2385.It Cd options FINNISH_KBD 2386Include translation for Finnish keyboards when using 2387.Em pccons 2388on a Shark. 2389.It Cd options GERMAN_KBD 2390Include translation for German keyboards when using 2391.Em pccons 2392on a Shark. 2393.It Cd options NORWEGIAN_KBD 2394Include translation for French keyboards when using 2395.Em pccons 2396on a Shark. 2397.El 2398.Ss amd64-specific Options 2399.Bl -ohang 2400.It Cd options ENHANCED_SPEEDSTEP 2401Include support for the 2402.Tn Enhanced SpeedStep Technology 2403present in newer 2404.Tn CPU Ns s . 2405.It Cd options EST_FREQ_USERWRITE 2406Allow any user to change the frequency of an 2407.Tn Enhanced SpeedStep Technology 2408capable 2409.Tn CPU . 2410.It Cd options INTEL_ONDEMAND_CLOCKMOD 2411This enables the On Demand Clock Modulation by software 2412on Intel 2413.Tn CPUs 2414supporting the Thermal Monitor feature (TM). 2415You can select the duty cycle with 2416.Xr sysctl 8 2417in the node 2418.Em machdep.clockmod 2419if supported. 2420.It Cd options POWERNOW_K8 2421Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2422Technology, used to change the cpu voltage and frequency 2423on the fly. 2424.El 2425.Ss atari-specific Options 2426.Bl -ohang 2427.It Cd options DISKLABEL_AHDI 2428Include support for AHDI (native Atari) disklabels. 2429.It Cd options DISKLABEL_NBDA 2430Include support for 2431.Nx Ns Tn /atari 2432labels. 2433If you don't set this option, it will be set automatically. 2434.Nx Ns Tn /atari 2435will not work without it. 2436.It Cd options FALCON_SCSI 2437Include support for the 5380-SCSI configuration as found on the Falcon. 2438.It Cd options RELOC_KERNEL 2439If set, the kernel will relocate itself to TT-RAM, if possible. 2440This will give you a slightly faster system. 2441.Em Beware 2442that on some TT030 systems, 2443the system will frequently dump with MMU-faults with this option enabled. 2444.It Cd options SERCONSOLE 2445Allow the modem1-port to act as the system-console. 2446A carrier should be active on modem1 during system boot to active 2447the console functionality. 2448.It Cd options TT_SCSI 2449Include support for the 5380-SCSI configuration as found on the TT030 2450and Hades. 2451.El 2452.Ss i386-specific Options 2453.Bl -ohang 2454.It Cd options ENHANCED_SPEEDSTEP 2455Include support for the 2456.Tn Enhanced SpeedStep Technology 2457present in newer 2458.Tn CPU Ns s . 2459.It Cd options EST_FREQ_USERWRITE 2460Allow any user to change the frequency of an 2461.Tn Enhanced SpeedStep Technology 2462capable 2463.Tn CPU . 2464.It Cd options INTEL_ONDEMAND_CLOCKMOD 2465This enables the On Demand Clock Modulation by software 2466on Intel 2467.Tn CPUs 2468supporting the Thermal Monitor feature (TM). 2469You can select the duty cycle with 2470.Xr sysctl 8 2471in the node 2472.Em machdep.clockmod 2473if supported. 2474.It Cd options POWERNOW_K7 2475Include support for the AMD 2476.Tn PowerNow! Technology 2477present in AMD Athlon Mobile processors. 2478.It Cd options VIA_PADLOCK 2479Include support for the 2480.Tn AES 2481encryption instructions of the 2482.Tn VIA PadLock Security engine , 2483which is attached as a provider to the opencrypto framework. 2484.It Cd options CPURESET_DELAY=value 2485Specifies the time (in millisecond) to wait before doing a hardware reset 2486in the last phase of a reboot. 2487This gives the user a chance to see error messages from the shutdown 2488operations (like NFS unmounts, buffer cache flush, etc ...). 2489Setting this to 0 will disable the delay. 2490Default is 2 seconds. 2491.It Cd options VM86 2492Include support for virtual 8086 mode, used by 2493.Tn DOS 2494emulators and X servers to run BIOS code, e.g., for some VESA routines. 2495.It Cd options USER_LDT 2496Include i386-specific system calls for modifying the local descriptor table, 2497used by Windows emulators. 2498.It Cd options REALBASEMEM=integer 2499Overrides the base memory size passed in from the boot block. 2500(Value given in kilobytes.) 2501Use this option only if the boot block reports the size incorrectly. 2502(Note that some 2503.Tn BIOS Ns es 2504put the extended 2505.Tn BIOS 2506data area at the top of base memory, and therefore report a smaller 2507base memory size to prevent programs overwriting it. 2508This is correct behavior, and you should not use the 2509.Em REALBASEMEM 2510option to access this memory). 2511.It Cd options REALEXTMEM=integer 2512Overrides the extended memory size passed in from the boot block. 2513(Value given in kilobytes. 2514Extended memory does not include the first megabyte.) 2515Use this option only if the boot block reports the size incorrectly. 2516.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2517Select a non-US keyboard layout for the 2518.Em pccons 2519console driver. 2520.It Cd options CYRIX_CACHE_WORKS 2521Relevant only to the Cyrix 486DLC CPU. 2522This option is used to turn on the cache in hold-flush mode. 2523It is not turned on by default because it is known to have problems in 2524certain motherboard implementations. 2525.It Cd options CYRIX_CACHE_REALLY_WORKS 2526Relevant only to the Cyrix 486DLC CPU. 2527This option is used to turn on the cache in write-back mode. 2528It is not turned on by default because it is known to have problems in 2529certain motherboard implementations. 2530In order for this option to take effect, option 2531.Em CYRIX_CACHE_WORKS 2532must also be specified. 2533.It Cd options PCIBIOS 2534Enable support for initializing the 2535.Tn PCI 2536bus using information from the 2537.Tn BIOS . 2538See 2539.Xr pcibios 4 2540for details. 2541.It Cd options KSTACK_CHECK_DR0 2542Detect kernel stack overflow using DR0 register. 2543This option uses DR0 register exclusively so you can't use DR0 register for 2544other purpose (e.g., hardware breakpoint) if you turn this on. 2545.It Cd options MTRR 2546Include support for accessing MTRR registers from user-space. 2547See 2548.Xr i386_get_mtrr 2 . 2549.It Cd options BEEP_ONHALT 2550Make the system speaker emit several beeps when it is completely safe to 2551power down the computer after a 2552.Xr halt 8 2553command. 2554Requires 2555.Xr sysbeep 4 2556support. 2557.It Cd options BEEP_ONHALT_COUNT=times 2558Number of times to beep the speaker when 2559.Cd options BEEP_ONHALT 2560is enabled. 2561Defaults to 3. 2562.It Cd options BEEP_ONHALT_PITCH=hz 2563The tone frequency used when 2564.Cd options BEEP_ONHALT 2565option, in hertz. 2566Defaults to 1500. 2567.It Cd options BEEP_ONHALT_PERIOD=msecs 2568The duration of each beep when 2569.Cd options BEEP_ONHALT 2570is enabled, in milliseconds. 2571Defaults to 250. 2572.It Cd options MULTIBOOT 2573Makes the kernel Multiboot-compliant, allowing it to be booted through 2574a Multiboot-compliant boot manager such as GRUB. 2575See 2576.Xr multiboot 8 2577for more information. 2578.El 2579.Ss isa-specific Options 2580Options specific to 2581.Xr isa 4 2582busses. 2583.Bl -ohang 2584.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2585Control the section of IO bus space used for PCMCIA bus space mapping. 2586Ideally the probed defaults are satisfactory, however in practice 2587that is not always the case. 2588See 2589.Xr pcmcia 4 2590for details. 2591.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2592Controls the allowable interrupts that may be used for 2593.Tn PCMCIA 2594devices. 2595This mask is a logical-or of power-of-2s of allowable interrupts: 2596.Bd -literal -offset 04n 2597.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2598 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2599 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2600 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2601 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2602.Ed 2603.It Cd options PCKBC_CNATTACH_SELFTEST 2604Perform a self test of the keyboard controller before attaching it as a 2605console. 2606This might be necessary on machines where we boot on cold iron, and 2607pckbc refuses to talk until we request a self test. 2608Currently only the netwinder port uses it. 2609.It Cd options PCKBD_CNATTACH_MAY_FAIL 2610If this option is set the PS/2 keyboard will not be used as the console 2611if it cannot be found during boot. 2612This allows other keyboards, like USB, to be the console keyboard. 2613.It Cd options PCKBD_LAYOUT=layout 2614Sets the default keyboard layout, see 2615.Xr pckbd 4 . 2616.El 2617.Ss m68k-specific Options 2618.Bl -ohang 2619.It Cd options FPU_EMULATE 2620Include support for MC68881/MC68882 emulator. 2621.It Cd options FPSP 2622Include support for 68040 floating point. 2623.It Cd options M68020,M68030,M68040,M68060 2624Include support for a specific 2625.Tn CPU , 2626at least one (the one you are using) should be specified. 2627.It Cd options M060SP 2628Include software support for 68060. 2629This provides emulation of unimplemented 2630integer instructions as well as emulation of unimplemented floating point 2631instructions and data types and software support for floating point traps. 2632.El 2633.Ss powerpc-specific Options (OEA Only) 2634.Bl -ohang 2635.It Cd options PMAP_MEMLIMIT=value 2636Limit the amount of memory seen by the kernel to 2637.Ar value 2638bytes. 2639.It Cd options PTEGCOUNT=value 2640Specify the size of the page table as 2641.Ar value 2642PTE groups. 2643Normally, one PTEG is allocated per physical page frame. 2644.El 2645.Ss sparc-specific Options 2646.Bl -ohang 2647.It Cd options AUDIO_DEBUG 2648Enable simple event debugging of the logging of the 2649.Xr audio 4 2650device. 2651.It Cd options BLINK 2652Enable blinking of LED. 2653Blink rate is full cycle every N seconds for 2654N \*[Lt] then current load average. 2655See 2656.Xr getloadavg 3 . 2657.\" .It Cd options COLORFONT_CACHE 2658.\" What does this do? 2659.It Cd options COUNT_SW_LEFTOVERS 2660Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2661sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2662variables accessible from 2663.Xr ddb 4 . 2664See 2665.Xr sw 4 . 2666.It Cd options DEBUG_ALIGN 2667Adds debugging messages calls when user-requested alignment fault 2668handling happens. 2669.It Cd options DEBUG_EMUL 2670Adds debugging messages calls for emulated floating point and 2671alignment fixing operations. 2672.It Cd options DEBUG_SVR4 2673Prints registers messages calls for emulated SVR4 getcontext and 2674setcontext operations. 2675See 2676.Em options COMPAT_SVR4 . 2677.It Cd options EXTREME_DEBUG 2678Adds debugging functions callable from 2679.Xr ddb 4 . 2680The debug_pagetables, test_region and print_fe_map 2681functions print information about page tables for the SUN4M 2682platforms only. 2683.It Cd options EXTREME_EXTREME_DEBUG 2684Adds extra info to 2685.Em options EXTREME_DEBUG . 2686.It Cd options FPU_CONTEXT 2687Make 2688.Em options COMPAT_SVR4 2689getcontext and setcontext include floating point registers. 2690.It Cd options MAGMA_DEBUG 2691Adds debugging messages to the 2692.Xr magma 4 2693device. 2694.It Cd options RASTERCONS_FULLSCREEN 2695Use the entire screen for the console. 2696.It Cd options RASTERCONS_SMALLFONT 2697Use the Fixed font on the console, instead of the normal font. 2698.It Cd options SUN4 2699Support sun4 class machines. 2700.It Cd options SUN4C 2701Support sun4c class machines. 2702.It Cd options SUN4M 2703Support sun4m class machines. 2704.It Cd options SUN4_MMU3L 2705.\" XXX ??? 2706Enable support for sun4 3-level MMU machines. 2707.It Cd options V9 2708Enable SPARC V9 assembler in 2709.Xr ddb 4 . 2710.El 2711.Ss sparc64-specific Options 2712.Bl -ohang 2713.It Cd options AUDIO_DEBUG 2714Enable simple event debugging of the logging of the 2715.Xr audio 4 2716device. 2717.It Cd options BLINK 2718Enable blinking of LED. 2719Blink rate is full cycle every N seconds for 2720N \*[Lt] then current load average. 2721See 2722.Xr getloadavg 3 . 2723.El 2724.Ss x68k-specific Options 2725.Bl -ohang 2726.It Cd options EXTENDED_MEMORY 2727Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2728.It Cd options JUPITER 2729Include support for Jupiter-X MPU accelerator 2730.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2731Use the built-in serial port as the system-console. 2732Speed is specified in bps, defaults to 9600. 2733.It Cd options ITE_KERNEL_ATTR=value 2734Set the kernel message attribute for ITE. 2735Value, an integer, is a logical or of the following values: 2736.Bl -tag -width 4n -compact -offset indent 2737.It 1 2738color inversed 2739.It 2 2740underlined 2741.It 4 2742bolded 2743.El 2744.El 2745.\" The following requests should be uncommented and used where appropriate. 2746.\" .Sh FILES 2747.\" .Sh EXAMPLES 2748.Sh SEE ALSO 2749.Xr config 1 , 2750.Xr gdb 1 , 2751.Xr ktrace 1 , 2752.Xr pmc 1 , 2753.Xr quota 1 , 2754.Xr vndcompress 1 , 2755.Xr gettimeofday 2 , 2756.Xr i386_get_mtrr 2 , 2757.Xr i386_iopl 2 , 2758.Xr msgctl 2 , 2759.Xr msgget 2 , 2760.Xr msgrcv 2 , 2761.Xr msgsnd 2 , 2762.Xr ntp_adjtime 2 , 2763.Xr ntp_gettime 2 , 2764.Xr reboot 2 , 2765.Xr semctl 2 , 2766.Xr semget 2 , 2767.Xr semop 2 , 2768.Xr shmat 2 , 2769.Xr shmctl 2 , 2770.Xr shmdt 2 , 2771.Xr shmget 2 , 2772.Xr sysctl 3 , 2773.Xr apm 4 , 2774.Xr ddb 4 , 2775.Xr inet 4 , 2776.Xr iso 4 , 2777.Xr md 4 , 2778.Xr ns 4 , 2779.Xr pcibios 4 , 2780.Xr pcmcia 4 , 2781.Xr ppp 4 , 2782.Xr userconf 4 , 2783.Xr vnd 4 , 2784.Xr wscons 4 , 2785.Xr config 5 , 2786.Xr edquota 8 , 2787.Xr init 8 , 2788.Xr mdsetimage 8 , 2789.Xr mount_cd9660 8 , 2790.Xr mount_fdesc 8 , 2791.Xr mount_kernfs 8 , 2792.Xr mount_lfs 8 , 2793.Xr mount_mfs 8 , 2794.Xr mount_msdos 8 , 2795.Xr mount_nfs 8 , 2796.Xr mount_ntfs 8 , 2797.Xr mount_null 8 , 2798.Xr mount_portal 8 , 2799.Xr mount_procfs 8 , 2800.Xr mount_udf 8 , 2801.Xr mount_umap 8 , 2802.Xr mount_union 8 , 2803.Xr mrouted 8 , 2804.Xr newfs_lfs 8 , 2805.Xr ntpd 8 , 2806.Xr quotaon 8 , 2807.Xr rpc.rquotad 8 , 2808.Xr sysctl 8 , 2809.Xr in_getifa 9 2810.Sh HISTORY 2811The 2812.Nm 2813man page first appeared in 2814.Nx 1.3 . 2815.Sh BUGS 2816The 2817.Em EON 2818option should be a pseudo-device, and is also very fragile. 2819