1.\" $NetBSD: options.4,v 1.380 2009/06/24 23:10:02 zafer 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 April 10, 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 LOCKDEBUG 620Adds code to the kernel to detect incorrect use of locking primitives 621(mutex, rwlock, simplelock). 622This code will cause the kernel to check for dead lock conditions. 623It will also check for memory being freed to not contain initialised 624lock primitives. 625Functions for use in 626.Xr ddb 4 627to check lock chains etc. are also enabled. 628These checks are very expensive and can decrease performance on 629multi-processor machines by a factor of three. 630.It Cd options KSTACK_CHECK_MAGIC 631Check kernel stack usage and panic if stack overflow is detected. 632This check is performance sensitive because it scans stack on each context 633switch. 634.It Cd options KTRACE 635Add hooks for the system call tracing facility, which allows users to 636watch the system call invocation behavior of processes. 637See 638.Xr ktrace 1 639for details. 640.It Cd options MSGBUFSIZE=integer 641This option sets the size of the kernel message buffer. 642This buffer holds the kernel output of 643.Fn printf 644when not (yet) read by 645.Xr syslogd 8 . 646This is particularly useful when the system has crashed and you wish to lookup 647the kernel output from just before the crash. 648Also, since the autoconfig output becomes more and more verbose, 649it sometimes happens that the message buffer overflows before 650.Xr syslogd 8 651was able to read it. 652Note that not all systems are capable of obtaining a variable sized message 653buffer. 654There are also some systems on which memory contents are not preserved 655across reboots. 656.It Cd options MALLOCLOG 657Enables an event log for 658.Xr malloc 9 . 659Useful for tracking down 660.Dq Data modified on freelist 661and 662.Dq multiple free 663problems. 664.It Cd options MALLOCLOGSIZE=integer 665Defines the number of entries in the malloc log. 666Default is 100000 entries. 667.It Cd options UVMHIST 668Enables the UVM history logs, which create in-memory traces of 669various UVM activities. 670These logs can be displayed be calling 671.Fn uvmhist_dump 672or 673.Fn uvm_hist 674with appropriate arguments from DDB. 675See the kernel source file sys/uvm/uvm_stat.c for details. 676.It Cd options UVMHIST_PRINT 677Prints the UVM history logs on the system console as entries are added. 678Note that the output is 679.Em extremely 680voluminous, so this option is really only useful for debugging 681the very earliest parts of kernel initialization. 682.El 683.Ss File Systems 684.Bl -ohang 685.It Cd file-system FFS 686Includes code implementing the Berkeley Fast File System 687.Po Em FFS Pc . 688Most machines need this if they are not running diskless. 689.It Cd file-system EXT2FS 690Includes code implementing the Second Extended File System 691.Po Em EXT2FS Pc , 692revision 0 and revision 1 with the 693.Em filetype 694and 695.Em sparse_super 696options. 697This is the most commonly used file system on the Linux operating system, 698and is provided here for compatibility. 699Some of the specific features of 700.Em EXT2FS 701like the "behavior on errors" are not implemented. 702This file system can't be used with UID or GID greater than 65535. 703See 704.Xr mount_ext2fs 8 705for details. 706.It Cd file-system LFS 707.Bq Em EXPERIMENTAL 708Include the Log-structured File System 709.Po Em LFS Pc . 710See 711.Xr mount_lfs 8 712and 713.Xr newfs_lfs 8 714for details. 715.It Cd file-system MFS 716Include the Memory File System 717.Po Em MFS Pc . 718This file system stores files in swappable memory, and produces 719notable performance improvements when it is used as the file store 720for 721.Pa /tmp 722and similar file systems. 723See 724.Xr mount_mfs 8 725for details. 726.It Cd file-system NFS 727Include the client side of the Network File System 728.Pq Tn NFS 729remote file sharing protocol. 730Although the bulk of the code implementing 731.Tn NFS 732is kernel based, several user level daemons are needed for it to work. 733See 734.Xr mount_nfs 8 735for details. 736.It Cd file-system CD9660 737Includes code for the 738.Tn ISO 7399660 + Rock Ridge file system, which is the standard file system on many 740.Tn CD-ROM 741discs. 742Useful primarily if you have a 743.Tn CD-ROM 744drive. 745See 746.Xr mount_cd9660 8 747for details. 748.It Cd file-system MSDOSFS 749Includes the 750.Tn MS-DOS 751FAT file system, which is reportedly still used 752by unfortunate people who have not heard about 753.Nx . 754Also implements the 755.Tn Windows 95 756extensions to the same, which permit the use of longer, mixed case 757file names. 758See 759.Xr mount_msdos 8 760and 761.Xr fsck_msdos 8 762for details. 763.It Cd file-system NTFS 764.Bq Em EXPERIMENTAL 765Includes code for the 766.Tn Microsoft Windows NT 767file system. 768See 769.Xr mount_ntfs 8 770for details. 771.It Cd file-system FDESC 772Includes code for a file system, conventionally mounted on 773.Pa /dev/fd , 774which permits access to the per-process file descriptor space via 775special files in the file system. 776See 777.Xr mount_fdesc 8 778for details. 779Note that this facility is redundant, and thus unneeded on most 780.Nx 781systems, since the 782.Xr fd 4 783pseudo-device driver already provides identical functionality. 784On most 785.Nx 786systems, instances of 787.Xr fd 4 788are mknoded under 789.Pa /dev/fd/ 790and on 791.Pa /dev/stdin , 792.Pa /dev/stdout , 793and 794.Pa /dev/stderr . 795.It Cd file-system KERNFS 796Includes code which permits the mounting of a special file system 797(normally mounted on 798.Pa /kern ) 799in which files representing various kernel variables and parameters 800may be found. 801See 802.Xr mount_kernfs 8 803for details. 804.It Cd file-system NULLFS 805Includes code for a loopback file system. 806This permits portions of the file hierarchy to be re-mounted in other places. 807The code really exists to provide an example of a stackable file system layer. 808See 809.Xr mount_null 8 810for details. 811.It Cd file-system OVERLAY 812Includes code for a file system filter. 813This permits the overlay file system to intercept all access to an underlying 814file system. 815This file system is intended to serve as an example of a stacking file 816system which has a need to interpose itself between an underlying file 817system and all other access. 818See 819.Xr mount_overlay 8 820for details. 821.It Cd file-system PORTAL 822.Bq Em EXPERIMENTAL 823Includes the portal file system. 824This permits interesting tricks like opening 825.Tn TCP 826sockets by opening files in the file system. 827The portal file system is conventionally mounted on 828.Pa /p 829and is partially implemented by a special daemon. 830See 831.Xr mount_portal 8 832for details. 833.It Cd file-system PROCFS 834Includes code for a special file system (conventionally mounted on 835.Pa /proc ) 836in which the process space becomes visible in the file system. 837Among 838other things, the memory spaces of processes running on the system are 839visible as files, and signals may be sent to processes by writing to 840.Pa ctl 841files in the procfs namespace. 842See 843.Xr mount_procfs 8 844for details. 845.It Cd file-system UDF 846.Bq Em EXPERIMENTAL 847Includes code for the UDF file system commonly found on CD and DVD 848media but also more and more on USB sticks. 849Useful primarily if you have a CD or a DVD drive, be it a read-only 850or a rewritable device. 851Currently only supports read-access. 852See 853.Xr mount_udf 8 854for details. 855.It Cd file-system UMAPFS 856Includes a loopback file system in which user and group IDs may be 857remapped -- this can be useful when mounting alien file systems with 858different UIDs and GIDs than the local system. 859See 860.Xr mount_umap 8 861for details. 862.It Cd file-system UNION 863.Bq Em EXPERIMENTAL 864Includes code for the union file system, which permits directories to 865be mounted on top of each other in such a way that both file systems 866remain visible -- this permits tricks like allowing writing (and the 867deleting of files) on a read-only file system like a 868.Tn CD-ROM 869by mounting a local writable file system on top of the read-only file system. 870See 871.Xr mount_union 8 872for details. 873.It Cd file-system CODA 874.Bq Em EXPERIMENTAL 875Includes code for the Coda file system. 876Coda is a distributed file system like NFS and AFS. 877It is freely available, like NFS, but it functions much like AFS in being a 878.Dq stateful 879file system. 880Both Coda and AFS cache files on your local machine to improve performance. 881Then Coda goes a step further than AFS by letting you access the cached 882files when there is no available network, viz. disconnected laptops and 883network outages. 884In Coda, both the client and server are outside the kernel which makes 885them easier to experiment with. 886Coda is available for several UNIX and non-UNIX platforms. 887See http://www.coda.cs.cmu.edu for more details. 888.Em NOTE : 889You also need to enable the pseudo-device, vcoda, for the Coda 890file system to work. 891.It Cd file-system SMBFS 892.Bq Em EXPERIMENTAL 893Includes code for the SMB/CIFS file system. 894See 895.Xr mount_smbfs 8 896for details. 897.Em NOTE : 898You also need to enable the pseudo-device, nsmb, for the SMB 899file system to work. 900.It Cd file-system PTYFS 901.Bq Em EXPERIMENTAL 902Includes code for a special file system (normally mounted on 903.Pa /dev/pts ) 904in which pseudo-terminal slave devices become visible in the file system. 905See 906.Xr mount_ptyfs 8 907for details. 908.It Cd file-system TMPFS 909Includes code for the efficient memory file system, normally used over 910.Pa /tmp . 911See 912.Xr mount_tmpfs 8 913for details. 914.It Cd file-system PUFFS 915.Bq Em EXPERIMENTAL 916Includes kernel support for the pass-to-userspace framework file system. 917It can be used to implement file system functionality in userspace. 918See 919.Xr puffs 3 920and 921.Xr puffs 4 922for more details. 923This option is required for sshfs: 924.Xr mount_psshfs 8 . 925.El 926.Ss File System Options 927.Bl -ohang 928.It Cd options MAGICLINKS 929Enables the expansion of special strings 930.Po 931beginning with 932.Dq @ 933.Pc 934when traversing symbolic links. 935See 936.Xr symlink 7 937for a list of supported strings. 938Note that this option only controls the enabling of this feature 939by the kernel at boot-up. 940This feature can still be manipulated with the 941.Xr sysctl 8 942command regardless of the setting of this option. 943.It Cd options NFSSERVER 944Include the server side of the 945.Em NFS 946(Network File System) remote file sharing protocol. 947Although the bulk of the code implementing 948.Em NFS 949is kernel based, several user level daemons are needed for it to 950work. 951See 952.Xr mountd 8 953and 954.Xr nfsd 8 955for details. 956.It Cd options QUOTA 957Enables kernel support for file system quotas. 958See 959.Xr quotaon 8 , 960.Xr edquota 8 , 961and 962.Xr quota 1 963for details. 964Note that quotas only work on 965.Dq ffs 966file systems, although 967.Xr rpc.rquotad 8 968permits them to be accessed over 969.Em NFS . 970.It Cd options FFS_EI 971Enable ``Endian-Independent'' FFS support. 972This allows a system to mount an FFS file system created for another 973architecture, at a small performance cost for all FFS file systems. 974See also 975.Xr newfs 8 , 976.Xr fsck_ffs 8 , 977.Xr dumpfs 8 978for file system byte order status and manipulation. 979.It Cd options FFS_NO_SNAPSHOT 980Disable the 981.Dq file system snapshot 982support in FFS file systems. 983Maybe useful for install media kernels, small memory systems and 984embedded systems which don't require the snapshot support. 985.It Cd options WAPBL 986Enable 987.Dq Write Ahead Physical Block Logging file system journaling . 988This provides rapid file system consistency checking after a system outage. 989It also provides better general use performance over regular FFS. 990See also 991.Xr wapbl 4 . 992.It Cd options NVNODE=integer 993This option sets the size of the cache used by the name-to-inode translation 994routines, (a.k.a. the 995.Fn namei 996cache, though called by many other names in the kernel source). 997By default, this cache has 998.Dv NPROC 999(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 1000A reasonable way to derive a value of 1001.Dv NVNODE , 1002should you notice a large number of namei cache misses with a tool such as 1003.Xr systat 1 , 1004is to examine your system's current computed value with 1005.Xr sysctl 8 , 1006(which calls this parameter "kern.maxvnodes") and to increase this value 1007until either the namei cache hit rate improves or it is determined that 1008your system does not benefit substantially from an increase in the size of 1009the namei cache. 1010.It Cd options NAMECACHE_ENTER_REVERSE 1011Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1012as well as a normal one. 1013Normally, this is already done for directory vnodes, to speed up the getcwd 1014operation. 1015This option will cause longer hash chains in the reverse cache, and thus 1016slow down getcwd somewhat. 1017However, it does make vnode -\*[Gt] path translations possible in some cases. 1018For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1019required. 1020.It Cd options EXT2FS_SYSTEM_FLAGS 1021This option changes the behavior of the APPEND and IMMUTABLE flags 1022for a file on an 1023.Em EXT2FS 1024file system. 1025Without this option, the superuser or owner of the file can 1026set and clear them. 1027With this option, only the superuser can set them, and 1028they can't be cleared if the securelevel is greater than 0. 1029See also 1030.Xr chflags 1 1031and 1032.Xr secmodel_securelevel 9 . 1033.It Cd options NFS_BOOT_BOOTP 1034Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1035information if NFS is used to mount the root file system. 1036See 1037.Xr diskless 8 1038for details. 1039.It Cd options NFS_BOOT_DHCP 1040Same as 1041.Dq NFS_BOOT_BOOTP , 1042but use the DHCP extensions to the 1043BOOTP protocol (RFC 1541). 1044.It Cd options NFS_BOOT_BOOTP_REQFILE 1045Specifies the string sent in the bp_file field of the BOOTP / DHCP 1046request packet. 1047.It Cd options NFS_BOOT_BOOTPARAM 1048Enable use of the BOOTPARAM protocol, consisting of RARP and 1049BOOTPARAM RPC, to get configuration information if NFS 1050is used to mount the root file system. 1051See 1052.Xr diskless 8 1053for details. 1054.It Cd options NFS_BOOT_RWSIZE=value 1055Set the initial NFS read and write sizes for diskless-boot requests. 1056The normal default is 8Kbytes. 1057This option provides a way to lower the value (e.g., to 1024 bytes) 1058as a workaround for buggy network interface cards or boot PROMs. 1059Once booted, the read and write request sizes can be increased by 1060remounting the file system. 1061See 1062.Xr mount_nfs 8 1063for details. 1064.It Cd options NFS_V2_ONLY 1065Reduce the size of the NFS client code by omitting code that's only required 1066for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1067servers. 1068.It Cd options UFS_DIRHASH 1069Increase lookup performance by maintaining in-core hash tables 1070for large directories. 1071.El 1072.Ss Buffer queue strategy options 1073The following options enable alternative buffer queue strategies. 1074.Bl -ohang 1075.It Cd options BUFQ_READPRIO 1076Enable experimental buffer queue strategy for disk I/O. 1077In the default strategy, outstanding disk requests are ordered by 1078sector number and sent to the disk, regardless of whether the 1079operation is a read or write; this option gives priority to issuing 1080read requests over write requests. 1081Although requests may therefore be issued out of sector-order, causing 1082more seeks and thus lower overall throughput, interactive system 1083responsiveness under heavy disk I/O load may be improved, as processes 1084blocking on disk reads are serviced sooner (file writes typically 1085don't cause applications to block). 1086The performance effect varies greatly depending on the hardware, drive 1087firmware, file system configuration, workload, and desired performance 1088trade-off. 1089Systems using drive write-cache (most modern IDE disks, by default) 1090are unlikely to benefit and may well suffer; such disks acknowledge 1091writes very quickly, and optimize them internally according to 1092physical layout. 1093Giving these disks as many requests to work with as possible (the 1094standard strategy) will typically produce the best results, especially 1095if the drive has a large cache; the drive will silently complete 1096writes from cache as it seeks for reads. 1097Disks that support a large number of concurrent tagged requests (SCSI 1098disks and many hardware RAID controllers) expose this internal 1099scheduling with tagged responses, and don't block for reads; such 1100disks may not see a noticeable difference with either strategy. 1101However, if IDE disks are run with write-cache disabled for safety, 1102writes are not acknowledged until actually completed, and only one 1103request can be outstanding; a large number of small writes in one 1104locality can keep the disk busy, starving reads elsewhere on the disk. 1105Such systems are likely to see the most benefit from this option. 1106Finally, the performance interaction of this option with ffs soft 1107dependencies can be subtle, as that mechanism can drastically alter 1108the workload for file system metadata writes. 1109.It Cd options BUFQ_PRIOCSCAN 1110Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1111.It Cd options NEW_BUFQ_STRATEGY 1112Synonym of 1113.Em BUFQ_READPRIO . 1114.El 1115.Ss Miscellaneous Options 1116.Bl -ohang 1117.It Cd options MEMORY_DISK_DYNAMIC 1118This option makes the 1119.Xr md 4 1120.Tn RAM 1121disk size dynamically sized. 1122It is incompatible with 1123.Xr mdsetimage 8 . 1124.It Cd options MEMORY_DISK_HOOKS 1125This option allows for some machine dependent functions to be called when 1126the 1127.Xr md 4 1128.Tn RAM 1129disk driver is configured. 1130This can result in automatically loading a 1131.Tn RAM 1132disk from floppy on open (among other things). 1133.It Cd options MEMORY_DISK_IS_ROOT 1134Forces the 1135.Xr md 4 1136.Tn RAM 1137disk to be the root device. 1138This can only be overridden when 1139the kernel is booted in the 'ask-for-root' mode. 1140.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1141Allocates the given number of 512 byte blocks as memory for the 1142.Xr md 4 1143.Tn RAM 1144disk, to be populated with 1145.Xr mdsetimage 8 . 1146.It Cd options MEMORY_DISK_SERVER=0 1147Do not include the interface to a userland memory disk server process. 1148Per default, this option is set to 1, including the support code. 1149Useful for install media kernels. 1150.It Cd options MEMORY_DISK_RBFLAGS=value 1151This option sets the 1152.Xr reboot 2 1153flags used when booting with a memory disk as root file system. 1154Possible values include 1155.Dv RB_AUTOBOOT 1156(boot in the usual fashion - default value), and 1157.Dv RB_SINGLE 1158(boot in single-user mode). 1159.It Cd options MODULAR 1160Enables the framework for kernel modules. 1161.It Cd options VND_COMPRESSION 1162Enables the 1163.Xr vnd 4 1164driver to also handle compressed images. 1165See 1166.Xr vndcompress 1 , 1167.Xr vnd 4 1168and 1169.Xr vnconfig 8 1170for more information. 1171.It Cd options TFTPROOT 1172Download the root memory disk through TFTP at root mount time. 1173This enables the use of a root 1174.Tn RAM 1175disk without requiring it to be embedded in the kernel using 1176.Xr mdsetimage 8 . 1177The 1178.Tn RAM 1179disk name is obtained using DHCP's filename parameter. 1180This option requires 1181.Em MEMORY_DISK_HOOKS , 1182.Em MEMORY_DISK_DYNAMIC , 1183and 1184.Em MEMORY_DISK_IS_ROOT . 1185It is incompatible with 1186.Em MEMORY_DISK_ROOT_SIZE . 1187.It Cd options MALLOC_NOINLINE 1188Time critical fixed size memory allocation is performed with 1189.Fn MALLOC 1190and 1191.Fn FREE . 1192Normally these expand to inline code, but with 1193.Em MALLOC_NOINLINE 1194these call the normal 1195.Fn malloc 1196and 1197.Fn free 1198functions. 1199Useful for install media kernels, small memory systems and embedded systems. 1200.It Cd options HZ=integer 1201On ports that support it, set the system clock frequency (see 1202.Xr hz 9 ) 1203to the supplied value. 1204Handle with care. 1205.It Cd options NTP 1206Turns on in-kernel precision timekeeping support used by software 1207implementing 1208.Em NTP 1209(Network Time Protocol, RFC 1305). 1210The 1211.Em NTP 1212option adds an in-kernel Phase-Locked Loop (PLL) for normal 1213.Em NTP 1214operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1215operation. 1216.Xr ntpd 8 1217will employ a user-level PLL when kernel support is unavailable, 1218but the in-kernel version has lower latency and more precision, and 1219so typically keeps much better time. 1220The interface to the kernel 1221.Em NTP 1222support is provided by the 1223.Xr ntp_adjtime 2 1224and 1225.Xr ntp_gettime 2 1226system calls, which are intended for use by 1227.Xr ntpd 8 1228and are enabled by the option. 1229On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1230is not an integer, the 1231.Em NTP 1232option also enables extended-precision arithmetic to keep track of 1233fractional clock ticks at NTP time-format precision. 1234.It Cd options PPS_SYNC 1235This option enables a kernel serial line discipline for receiving time 1236phase signals from an external reference clock such as a radio clock. 1237(The 1238.Em NTP 1239option (which see) must be on if the 1240.Em PPS_SYNC 1241option is used.) 1242Some reference clocks generate a Pulse Per Second (PPS) signal in 1243phase with their time source. 1244The 1245.Em PPS 1246line discipline receives this signal on either the data leads 1247or the DCD control lead of a serial port. 1248.Em NTP 1249uses the PPS signal to discipline the local clock oscillator to a high 1250degree of precision (typically less than 50 microseconds in time and 12510.1 ppm in accuracy). 1252.Em PPS 1253can also generate a serial output pulse when the system receives a PPS 1254interrupt. 1255This can be used to measure the system interrupt latency and thus calibrate 1256.Em NTP 1257to account for it. 1258Using 1259.Em PPS 1260usually requires a 1261gadget box 1262to convert from TTL to RS-232 signal levels. 1263The gadget box and PPS are described in more detail in the HTML documentation 1264for 1265.Xr ntpd 8 1266in 1267.Pa /usr/share/doc/html/ntp . 1268.It Cd options SETUIDSCRIPTS 1269Allows scripts with the setuid bit set to execute as the effective 1270user rather than the real user, just like binary executables. 1271.Pp 1272.Em NOTE : 1273Using this option will also enable 1274.Em options FDSCRIPTS 1275.It Cd options FDSCRIPTS 1276Allows execution of scripts with the execute bit set, but not the 1277read bit, by opening the file and passing the file descriptor to 1278the shell, rather than the filename. 1279.Pp 1280.Em NOTE : 1281Execute only (non-readable) scripts will have 1282.Va argv[0] 1283set to 1284.Pa /dev/fd/* . 1285What this option allows as far as security is 1286concerned, is the ability to safely ensure that the correct script 1287is run by the interpreter, as it is passed as an already open file. 1288.It Cd options PUCCN 1289Enables treating serial ports found on PCI boards 1290.Xr puc 4 1291as potential console devices. 1292The method for choosing such a console device is port dependent. 1293.It Cd options RTC_OFFSET=integer 1294The kernel (and typically the hardware battery backed-up clock on 1295those machines that have one) keeps time in 1296.Em UTC 1297(Universal Coordinated Time, once known as 1298.Em GMT , 1299or Greenwich Mean Time) 1300and not in the time of the local time zone. 1301The 1302.Em RTC_OFFSET 1303option is used on some ports (such as the i386) to tell the kernel 1304that the hardware clock is offset from 1305.Em UTC 1306by the specified number of minutes. 1307This is typically used when a machine boots several operating 1308systems and one of them wants the hardware clock to run in the 1309local time zone and not in 1310.Em UTC , 1311e.g. 1312.Em RTC_OFFSET=300 1313means 1314the hardware clock is set to US Eastern Time (300 minutes behind 1315.Em UTC ) , 1316and not 1317.Em UTC . 1318(Note: 1319.Em RTC_OFFSET 1320is used to initialize a kernel variable named 1321.Va rtc_offset 1322which is the source actually used to determine the clock offset, and 1323which may be accessed via the kern.rtc_offset sysctl variable. 1324See 1325.Xr sysctl 8 1326and 1327.Xr sysctl 3 1328for details. 1329Since the kernel clock is initialized from the hardware clock very 1330early in the boot process, it is not possible to meaningfully change 1331.Va rtc_offset 1332in system initialization scripts. 1333Changing this value currently may only be done at kernel compile 1334time or by patching the kernel and rebooting). 1335.Pp 1336.Em NOTE : 1337Unfortunately, in many cases where the hardware clock 1338is kept in local time, it is adjusted for Daylight Savings 1339Time; this means that attempting to use 1340.Em RTC_OFFSET 1341to let 1342.Nx 1343coexist with such an operating system, like Windows, 1344would necessitate changing 1345.Em RTC_OFFSET 1346twice a year. 1347As such, this solution is imperfect. 1348.It Cd options KMEMSTATS 1349The kernel memory allocator, 1350.Xr malloc 9 , 1351will keep statistics on its performance if this option is enabled. 1352Unfortunately, this option therefore essentially disables the 1353.Fn MALLOC 1354and 1355.Fn FREE 1356forms of the memory allocator, which are used to enhance the performance 1357of certain critical sections of code in the kernel. 1358This option therefore can lead to a significant decrease in the 1359performance of certain code in the kernel if enabled. 1360Examples of such code include the 1361.Fn namei 1362routine, the 1363.Xr ccd 4 1364driver, 1365and much of the networking code. 1366.It Cd options MAXUPRC=integer 1367Sets the soft 1368.Dv RLIMIT_NPROC 1369resource limit, which specifies the maximum number of simultaneous 1370processes a user is permitted to run, for process 0; 1371this value is inherited by its child processes. 1372It defaults to 1373.Em CHILD_MAX , 1374which is currently defined to be 160. 1375Setting 1376.Em MAXUPRC 1377to a value less than 1378.Em CHILD_MAX 1379is not permitted, as this would result in a violation of the semantics of 1380.St -p1003.1-90 . 1381.It Cd options NOFILE=integer 1382Sets the soft 1383.Dv RLIMIT_NOFILE 1384resource limit, which specifies the maximum number of open 1385file descriptors for each process; 1386this value is inherited by its child processes. 1387It defaults to 1388.Em OPEN_MAX , 1389which is currently defined to be 64. 1390.It Cd options MAXFILES=integer 1391Sets the default value of the 1392.Em kern.maxfiles 1393sysctl variable, which indicates the maximum number of files that may 1394be open in the system. 1395.It Cd options DEFCORENAME=string 1396Sets the default value of the 1397.Em kern.defcorename 1398sysctl variable, otherwise it is set to 1399.Nm %n.core . 1400See 1401.Xr sysctl 8 1402and 1403.Xr sysctl 3 1404for details. 1405.It Cd options RASOPS_CLIPPING 1406Enables clipping within the 1407.Nm rasops 1408raster-console output system. 1409.Em NOTE : 1410only available on architectures that use 1411.Nm rasops 1412for console output. 1413.It Cd options RASOPS_SMALL 1414Removes optimized character writing code from the 1415.Nm rasops 1416raster-console output system. 1417.Em NOTE : 1418only available on architectures that use 1419.Nm rasops 1420for console output. 1421.It Cd options INCLUDE_CONFIG_FILE 1422Embeds the kernel config file used to define the kernel in the kernel 1423binary itself. 1424The embedded data also includes any files directly included by the config 1425file itself, e.g. 1426.Pa GENERIC.local 1427or 1428.Pa std.$MACHINE . 1429The embedded config file can be extracted from the resulting kernel with 1430.Xr config 1 1431.Fl x , 1432or by the following command: 1433.Bd -literal -offset indent 1434strings netbsd | sed -n 's/^_CFG_//p' | unvis 1435.Ed 1436.It Cd options INCLUDE_JUST_CONFIG 1437Similar to the above option, but includes just the actual config file, 1438not any included files. 1439.It Cd options PIPE_SOCKETPAIR 1440Use slower, but smaller socketpair(2)-based pipe implementation instead 1441of default faster, but bigger one. 1442Primarily useful for installation kernels. 1443.It Cd options USERCONF 1444Compiles in the in-kernel device configuration manager. 1445See 1446.Xr userconf 4 1447for details. 1448.It Cd options PERFCTRS 1449Compiles in kernel support for CPU performance-monitoring counters. 1450See 1451.Xr pmc 1 1452for details. 1453.Em NOTE : 1454not available on all architectures. 1455.It Cd options SYSCALL_STATS 1456Count the number of times each system call number is called. 1457The values can be read through the sysctl interface and displayed using 1458.Xr systat 1 . 1459.Em NOTE : 1460not yet available on all architectures. 1461.It Cd options SYSCALL_TIMES 1462Count the time spent (using 1463.Fn cpu_counter32 ) 1464in each system call. 1465.Em NOTE : 1466Using this option will also enable 1467.Cd options SYSCALL_STATS . 1468.It Cd options SYSCALL_TIMES_HASCOUNTER 1469Force use of 1470.Fn cpu_counter32 1471even if 1472.Fn cpu_hascounter 1473reports false. 1474Useful for systems where the cycle counter doesn't run at a constant rate 1475(e.g. Soekris boxes). 1476.It Cd options XSERVER 1477Compiles in kernel support for 1478.Tn X11 1479on architectures that still use (or can use) the legacy 1480.Em pccons 1481console drivers rather than 1482.Xr wscons 4 . 1483These include bebox, i386, shark. 1484.It Cd options XSERVER_DDB 1485A supplement to XSERVER that adds support for entering 1486.Xr ddb 4 1487while in 1488.Tn X11 . 1489.It Cd options FILEASSOC 1490Support for 1491.Xr fileassoc 9 . 1492.It Cd options FILEASSOC_NHOOKS=integer 1493Number of storage slots per file for 1494.Xr fileassoc 9 . 1495Default is 4. 1496.It Cd options I2C_SCAN 1497Scan each i2c bus to determine which addresses respond. 1498.Pp 1499.Em WARNING ! 1500Using this option can access some devices in such a 1501manner as to leave them in an unstable or unuseable state, and 1502can prevent those devices from being properly matched and/or 1503attached. 1504It can also lock up the entire i2c bus and even 1505prevent a machine from completing the boot process. 1506Don't use this option unless you know what you're doing and can 1507accept all sorts of unforeseen consequences. 1508.El 1509.Ss Networking Options 1510.Bl -ohang 1511.It Cd options GATEWAY 1512Enables 1513.Em IPFORWARDING 1514(which see) 1515and (on most ports) increases the size of 1516.Em NMBCLUSTERS 1517(which see). 1518In general, 1519.Em GATEWAY 1520is used to indicate that a system should act as a router, and 1521.Em IPFORWARDING 1522is not invoked directly. 1523(Note that 1524.Em GATEWAY 1525has no impact on protocols other than 1526.Tn IP , 1527such as 1528.Tn CLNP 1529or 1530.Tn XNS ) . 1531.Em GATEWAY 1532option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1533.It Cd options ICMPPRINTFS 1534The 1535.Em ICMPPRINTFS 1536option will enable debugging information to be printed about 1537the 1538.Xr icmp 4 1539protocol. 1540.It Cd options IPFORWARDING=value 1541If 1542.Em value 1543is 1 this enables IP routing behavior. 1544If 1545.Em value 1546is 0 (the default), it disables it. 1547The 1548.Em GATEWAY 1549option sets this to 1 automatically. 1550With this option enabled, the machine will forward IP datagrams destined 1551for other machines between its interfaces. 1552Note that even without this option, the kernel will 1553still forward some packets (such as source routed packets) -- removing 1554.Em GATEWAY 1555and 1556.Em IPFORWARDING 1557is insufficient to stop all routing through a bastion host on a 1558firewall -- source routing is controlled independently. 1559To turn off source routing, use 1560.Em options IPFORWSRCRT=0 1561(which see). 1562Note that IP forwarding may be turned on and off independently of the 1563setting of the 1564.Em IPFORWARDING 1565option through the use of the 1566.Em net.inet.ip.forwarding 1567sysctl variable. 1568If 1569.Em net.inet.ip.forwarding 1570is 1, IP forwarding is on. 1571See 1572.Xr sysctl 8 1573and 1574.Xr sysctl 3 1575for details. 1576.It Cd options IPFORWSRCRT=value 1577If 1578.Em value 1579is set to zero, source routing of IP datagrams is turned off. 1580If 1581.Em value 1582is set to one (the default) or the option is absent, source routed IP 1583datagrams are forwarded by the machine. 1584Note that source routing of IP packets may be turned on and off 1585independently of the setting of the 1586.Em IPFORWSRCRT 1587option through the use of the 1588.Em net.inet.ip.forwsrcrt 1589sysctl variable. 1590If 1591.Em net.inet.ip.forwsrcrt 1592is 1, forwarding of source routed IP datagrams is on. 1593See 1594.Xr sysctl 8 1595and 1596.Xr sysctl 3 1597for details. 1598.It Cd options IFA_STATS 1599Tells the kernel to maintain per-address statistics on bytes sent 1600and received over (currently) Internet and AppleTalk addresses. 1601.\"This can be a fairly expensive operation, so you probably want to 1602.\"keep this disabled. 1603The option is not recommended as it degrades system stability. 1604.It Cd options IFQ_MAXLEN=value 1605Increases the allowed size of the network interface packet queues. 1606The default queue size is 50 packets, and you do not normally need 1607to increase it. 1608.It Cd options IPSELSRC 1609Includes support for source-address selection policies. 1610See 1611.Xr in_getifa 9 . 1612.It Cd options MROUTING 1613Includes support for IP multicast routers. 1614You certainly want 1615.Em INET 1616with this. 1617Multicast routing is controlled by the 1618.Xr mrouted 8 1619daemon. 1620See also option 1621.Cd PIM . 1622.It Cd options PIM 1623Includes support for Protocol Independent Multicast (PIM) routing. 1624You need 1625.Em MROUTING 1626and 1627.Em INET 1628with this. 1629Software using this can be found e.g. in 1630.Pa pkgsrc/net/xorp . 1631.It Cd options INET 1632Includes support for the 1633.Tn TCP/IP 1634protocol stack. 1635You almost certainly want this. 1636See 1637.Xr inet 4 1638for details. 1639.It Cd options INET6 1640Includes support for the 1641.Tn IPv6 1642protocol stack. 1643See 1644.Xr inet6 4 1645for details. 1646Unlike 1647.Em INET , 1648.Em INET6 1649enables multicast routing code as well. 1650This option requires 1651.Em INET 1652at this moment, but it should not. 1653.It Cd options ND6_DEBUG 1654The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1655for debugging IPv6 neighbor discovery protocol handling. 1656See 1657.Xr sysctl 3 1658for details. 1659.It Cd options IPSEC 1660Includes support for the 1661.Tn IPsec 1662protocol. 1663See 1664.Xr ipsec 4 1665for details. 1666.It Cd options IPSEC_DEBUG 1667Enables debugging code in 1668.Tn IPsec 1669stack. 1670See 1671.Xr ipsec 4 1672for details. 1673.It Cd options IPSEC_ESP 1674Includes support for 1675.Tn IPsec 1676.Tn ESP 1677protocol. 1678See 1679.Xr ipsec 4 1680for details. 1681.It Cd options IPSEC_NAT_T 1682Includes support for 1683.Tn IPsec 1684Network Address Translator traversal (NAT-T), as described in RFCs 3947 1685and 3948. 1686This feature might be patent-encumbered in some countries. 1687.It Cd options ALTQ 1688Enabled ALTQ (Alternate Queueing). 1689For simple rate-limiting, use 1690.Xr tbrconfig 8 1691to set up the interface transmission rate. 1692To use queueing disciplines, their appropriate kernel options should also 1693be defined (documented below). 1694Queueing disciplines are managed by 1695.Xr altqd 8 . 1696See 1697.Xr altq 9 1698for details. 1699.It Cd options ALTQ_HFSC 1700Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1701module. 1702HFSC supports both link-sharing and guaranteed real-time services. 1703HFSC employs a service curve based QoS model, and its unique feature 1704is an ability to decouple delay and bandwidth allocation. 1705Requires 1706.Em ALTQ_RED 1707to use the RED queueing discipline on HFSC classes, or 1708.Em ALTQ_RIO 1709to use the RIO queueing discipline on HFSC classes. 1710This option assumes 1711.Em ALTQ . 1712.It Cd options ALTQ_PRIQ 1713Include support for ALTQ-implemented PRIQ (Priority Queueing). 1714PRIQ implements a simple priority-based queueing discipline. 1715A higher priority class is always served first. 1716Requires 1717.Em ALTQ_RED 1718to use the RED queueing discipline on HFSC classes, or 1719.Em ALTQ_RIO 1720to use the RIO queueing discipline on HFSC classes. 1721This option assumes 1722.Em ALTQ . 1723.It Cd options ALTQ_WFQ 1724Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1725WFQ implements a weighted-round robin scheduler for a set of queues. 1726A weight can be assigned to each queue to give a different proportion 1727of the link capacity. 1728A hash function is used to map a flow to one of a set of queues. 1729This option assumes 1730.Em ALTQ . 1731.It Cd options ALTQ_FIFOQ 1732Include support for ALTQ-implemented FIFO queueing. 1733FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1734This option assumes 1735.Em ALTQ . 1736.It Cd options ALTQ_RIO 1737Include support for ALTQ-implemented RIO (RED with In/Out). 1738The original RIO has 2 sets of RED parameters; one for in-profile 1739packets and the other for out-of-profile packets. 1740At the ingress of the network, profile meters tag packets as IN or 1741OUT based on contracted profiles for customers. 1742Inside the network, IN packets receive preferential treatment by 1743the RIO dropper. 1744ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1745PHB of DiffServ (RFC 2597). 1746This option assumes 1747.Em ALTQ . 1748.It Cd options ALTQ_BLUE 1749Include support for ALTQ-implemented Blue buffer management. 1750Blue is another active buffer management mechanism. 1751This option assumes 1752.Em ALTQ . 1753.It Cd options ALTQ_FLOWVALVE 1754Include support for ALTQ-implemented Flowvalve. 1755Flowvalve is a simple implementation of a RED penalty box that identifies 1756and punishes misbehaving flows. 1757This option requires 1758.Em ALTQ_RED 1759and assumes 1760.Em ALTQ . 1761.It Cd options ALTQ_CDNR 1762Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1763packet marking/manipulation. 1764Traffic conditioners are components to meter, mark, or drop incoming 1765packets according to some rules. 1766As opposed to queueing disciplines, traffic conditioners handle incoming 1767packets at an input interface. 1768This option assumes 1769.Em ALTQ . 1770.It Cd options ALTQ_NOPCC 1771Disables use of processor cycle counter to measure time in ALTQ. 1772This option should be defined for a non-Pentium i386 CPU which does not 1773have TSC, SMP (per-CPU counters are not in sync), or power management 1774which affects processor cycle counter. 1775This option assumes 1776.Em ALTQ . 1777.It Cd options ALTQ_IPSEC 1778Include support for IPsec in IPv4 ALTQ. 1779This option assumes 1780.Em ALTQ . 1781.It Cd options ALTQ_JOBS 1782Include support for ALTQ-implemented JoBS (Joint Buffer Management 1783and Scheduling). 1784This option assumes 1785.Em ALTQ . 1786.It Cd options ALTQ_AFMAP 1787Include support for an undocumented ALTQ feature that is used to map an IP 1788flow to an ATM VC (Virtual Circuit). 1789This option assumes 1790.Em ALTQ . 1791.It Cd options ALTQ_LOCALQ 1792Include support for ALTQ-implemented local queues. 1793Its practical use is undefined. 1794Assumes 1795.Em ALTQ . 1796.It Cd options SUBNETSARELOCAL 1797Sets default value for net.inet.ip.subnetsarelocal variable, which 1798controls whether non-directly-connected subnets of connected networks 1799are considered "local" for purposes of choosing the MSS for a TCP 1800connection. 1801This is mostly present for historic reasons and completely irrelevant if 1802you enable Path MTU discovery. 1803.It Cd options HOSTZEROBROADCAST 1804Sets default value for net.inet.ip.hostzerobroadcast variable, which 1805controls whether the zeroth host address of each connected subnet is 1806also considered a broadcast address. 1807Default value is "1", for compatibility with old systems; if this is 1808set to zero on all hosts on a subnet, you should be able to fit an extra 1809host per subnet on the 1810".0" address. 1811.It Cd options MCLSHIFT=value 1812This option is the base-2 logarithm of the size of mbuf clusters. 1813The 1814.Bx 1815networking stack keeps network packets in a linked 1816list, or chain, of kernel buffer objects called mbufs. 1817The system provides larger mbuf clusters as an optimization for 1818large packets, instead of using long chains for large packets. 1819The mbuf cluster size, 1820or 1821.Em MCLBYTES , 1822must be a power of two, and is computed as two raised to the power 1823.Em MCLSHIFT . 1824On systems with Ethernet network adapters, 1825.Em MCLSHIFT 1826is often set to 11, giving 2048-byte mbuf clusters, large enough to 1827hold a 1500-byte 1828.Tn Ethernet 1829frame in a single cluster. 1830Systems with network interfaces supporting larger frame sizes like 1831.Tn ATM , 1832.Tn FDDI , 1833or 1834.Tn HIPPI 1835may perform better with 1836.Em MCLSHIFT 1837set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1838respectively. 1839.It Cd options NS 1840Include support for the 1841.Tn Xerox 1842.Tn XNS 1843protocol stack. 1844See 1845.Xr ns 4 1846for details. 1847.It Cd options ISO,TPIP 1848Include support for the ubiquitous 1849.Tn OSI 1850protocol stack. 1851See 1852.Xr iso 4 1853for details. 1854This option assumes 1855.Em INET . 1856.It Cd options EON 1857Include support for tunneling 1858.Tn OSI 1859protocols over 1860.Tn IP . 1861Known to be broken, or at least very fragile, and undocumented. 1862.It Cd options NETATALK 1863Include support for the 1864.Tn AppleTalk 1865protocol stack. 1866The kernel provides provision for the 1867.Em Datagram Delivery Protocol 1868(DDP), providing SOCK_DGRAM support and 1869.Tn AppleTalk 1870routing. 1871This stack is used by the 1872.Em NETATALK 1873package, which adds support for 1874.Tn AppleTalk 1875server services via user libraries and applications. 1876.It Cd options BLUETOOTH 1877Include support for the 1878.Tn Bluetooth 1879protocol stack. 1880See 1881.Xr bluetooth 4 1882for details. 1883.It Cd options IPNOPRIVPORTS 1884Normally, only root can bind a socket descriptor to a so-called 1885.Dq privileged 1886.Tn TCP 1887port, that is, a port number in the range 0-1023. 1888This option eliminates those checks from the kernel. 1889This can be useful if there is a desire to allow daemons without 1890privileges to bind those ports, e.g., on firewalls. 1891The security tradeoffs in doing this are subtle. 1892This option should only be used by experts. 1893.It Cd options TCP_COMPAT_42 1894.Tn TCP 1895bug compatibility with 1896.Bx 4.2 . 1897In 1898.Bx 4.2 , 1899.Tn TCP 1900sequence numbers were 32-bit signed values. 1901Modern implementations of TCP use unsigned values. 1902This option clamps the initial sequence number to start in 1903the range 2^31 rather than the full unsigned range of 2^32. 1904Also, under 1905.Bx 4.2 , 1906keepalive packets must contain at least one byte or else 1907the remote end would not respond. 1908.It Cd options TCP_DEBUG 1909Record the last 1910.Em TCP_NDEBUG 1911TCP packets with SO_DEBUG set, and decode to the console if 1912.Em tcpconsdebug 1913is set. 1914.It Cd options TCP_NDEBUG 1915Number of packets to record for 1916.Em TCP_DEBUG . 1917Defaults to 100. 1918.It Cd options TCP_SENDSPACE=value 1919.It Cd options TCP_RECVSPACE=value 1920These options set the max TCP window size to other sizes than the default. 1921The TCP window sizes can be altered via 1922.Xr sysctl 8 1923as well. 1924.It Cd options TCP_INIT_WIN=value 1925This option sets the initial TCP window size for non-local connections, 1926which is used when the transmission starts. 1927The default size is 1, but if the machine should act more aggressively, 1928the initial size can be set to some other value. 1929The initial TCP window size can be set via 1930.Xr sysctl 8 1931as well. 1932.It Cd options PFIL_HOOKS 1933This option turns on the packet filter interface hooks. 1934See 1935.Xr pfil 9 1936for details. 1937This option assumes 1938.Em INET . 1939.It Cd options IPFILTER_LOG 1940This option, in conjunction with 1941.Em pseudo-device ipfilter , 1942enables logging of IP packets using ip-filter. 1943.It Cd options IPFILTER_DEFAULT_BLOCK 1944This option sets the default policy of ip-filter. 1945If it is set, ip-filter will block packets by default. 1946.It Cd options BRIDGE_IPF 1947This option causes 1948.Em bridge 1949devices to use the IP and/or IPv6 filtering hooks, forming 1950a link-layer filter that uses protocol-layer rules. 1951This option assumes the presence of 1952.Em pseudo-device ipfilter . 1953.It Cd options MBUFTRACE 1954This option can help track down mbuf leaks. 1955When enabled, mbufs are tagged with the devices and protocols using them, 1956which slightly decreases network performance. 1957This additional information can be viewed with 1958.Xr netstat 1 : 1959.Dl Ic netstat Fl mssv 1960Not all devices or protocols support this option. 1961.El 1962.Ss Sysctl Related Options 1963.Bl -ohang 1964.It Cd options SYSCTL_DISALLOW_CREATE 1965Disallows the creation or deletion of nodes from the sysctl tree, as 1966well as the assigning of descriptions to nodes that lack them, by any 1967process. 1968These operations are still available to kernel sub-systems, including 1969loadable kernel modules. 1970.It Cd options SYSCTL_DISALLOW_KWRITE 1971Prevents processes from adding nodes to the sysctl tree that make 1972existing kernel memory areas writable. 1973Sections of kernel memory can still be read and new nodes that own 1974their own data may still be writable. 1975.It Cd options SYSCTL_DEBUG_SETUP 1976Causes the SYSCTL_SETUP routines to print a brief message when they 1977are invoked. 1978This is merely meant as an aid in determining the order in which 1979sections of the tree are created. 1980.It Cd options SYSCTL_DEBUG_CREATE 1981Prints a message each time 1982.Fn sysctl_create , 1983the function that adds nodes to the tree, is called. 1984.It Cd options SYSCTL_INCLUDE_DESCR 1985Causes the kernel to include short, human readable descriptions for 1986nodes in the sysctl tree. 1987The descriptions can be retrieved programmatically (see 1988.Xr sysctl 3 ) , 1989or by the sysctl binary itself (see 1990.Xr sysctl 8 ) . 1991The descriptions are meant to give an indication of the purpose and/or 1992effects of a given node's value, not replace the documentation for the 1993given subsystem as a whole. 1994.El 1995.Ss System V IPC Options 1996.Bl -ohang 1997.It Cd options SYSVMSG 1998Includes support for 1999.At V 2000style message queues. 2001See 2002.Xr msgctl 2 , 2003.Xr msgget 2 , 2004.Xr msgrcv 2 , 2005.Xr msgsnd 2 . 2006.It Cd options SYSVSEM 2007Includes support for 2008.At V 2009style semaphores. 2010See 2011.Xr semctl 2 , 2012.Xr semget 2 , 2013.Xr semop 2 . 2014.It Cd options SEMMNI=value 2015Sets the number of 2016.At V 2017style semaphore identifiers. 2018The GENERIC config file for your port will have the default. 2019.It Cd options SEMMNS=value 2020Sets the number of 2021.At V 2022style semaphores in the system. 2023The GENERIC config file for your port will have the default. 2024.It Cd options SEMUME=value 2025Sets the maximum number of undo entries per process for 2026.At V 2027style semaphores. 2028The GENERIC config file for your port will have the default. 2029.It Cd options SEMMNU=value 2030Sets the number of undo structures in the system for 2031.At V 2032style semaphores. 2033The GENERIC config file for your port will have the default. 2034.It Cd options SYSVSHM 2035Includes support for 2036.At V 2037style shared memory. 2038See 2039.Xr shmat 2 , 2040.Xr shmctl 2 , 2041.Xr shmdt 2 , 2042.Xr shmget 2 . 2043.It Cd options SHMMAXPGS=value 2044Sets the maximum number of 2045.At V 2046style shared memory pages that are available through the 2047.Xr shmget 2 2048system call. 2049Default value is 1024 on most ports. 2050See 2051.Pa /usr/include/machine/vmparam.h 2052for the default. 2053.El 2054.Ss VM Related Options 2055.Bl -ohang 2056.It Cd options NMBCLUSTERS=value 2057The number of mbuf clusters the kernel supports. 2058Mbuf clusters are MCLBYTES in size (usually 2k). 2059This is used to compute the size of the kernel VM map 2060.Em mb_map , 2061which maps mbuf clusters. 2062Default on most ports is 1024 (2048 with 2063.Dq options GATEWAY 2064). 2065See 2066.Pa /usr/include/machine/param.h 2067for exact default information. 2068Increase this value if you get 2069.Dq mclpool limit reached 2070messages. 2071.It Cd options NKMEMPAGES=value 2072.It Cd options NKMEMPAGES_MIN=value 2073.It Cd options NKMEMPAGES_MAX=value 2074Size of kernel VM map 2075.Em kmem_map , 2076in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2077from the 2078.Xr sysctl 8 2079variable 2080.Em hw.pagesize 2081). 2082This VM map is used to map the kernel malloc arena. 2083The kernel attempts to auto-size this map based on the amount of 2084physical memory in the system. 2085Platform-specific code may place bounds on this computed size, 2086which may be viewed with the 2087.Xr sysctl 8 2088variable 2089.Em vm.nkmempages . 2090See 2091.Pa /usr/include/machine/param.h 2092for the default upper and lower bounds. 2093The related options 2094.Sq NKMEMPAGES_MIN 2095and 2096.Sq NKMEMPAGES_MAX 2097allow the bounds to be overridden in the kernel configuration file. 2098These options are provided in the event the computed value is 2099insufficient resulting in an 2100.Dq out of space in kmem_map 2101panic. 2102.It Cd options SB_MAX=value 2103Sets the max size in bytes that a socket buffer is allowed to occupy. 2104The default is 256k, but sometimes it needs to be increased, for example 2105when using large TCP windows. 2106This option can be changed via 2107.Xr sysctl 8 2108as well. 2109.It Cd options SOMAXKVA=value 2110Sets the maximum size of kernel virtual memory that the socket buffers 2111are allowed to use. 2112The default is 16MB, but in situations where for example large TCP 2113windows are used this value must also be increased. 2114This option can be changed via 2115.Xr sysctl 8 2116as well. 2117.It Cd options BUFCACHE=value 2118Size of the buffer cache as a percentage of total available 2119.Tn RAM . 2120Ignored if BUFPAGES is also specified. 2121.It Cd options NBUF=value 2122Sets the number of buffer headers available, i.e., the number of 2123open files that may have a buffer cache entry. 2124Each buffer header 2125requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2126The default value is machine dependent, but is usually equal to the 2127value of BUFPAGES. 2128If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2129then NBUF may be reduced at run time so that the storage allocated 2130for buffer headers doesn't exceed that limit. 2131.It Cd options BUFPAGES=value 2132These options set the number of pages available for the buffer cache. 2133Their default value is a machine dependent value, often calculated as 2134between 5% and 10% of total available 2135.Tn RAM . 2136.It Cd options MAXTSIZ=bytes 2137Sets the maximum size limit of a process' text segment. 2138See 2139.Pa /usr/include/machine/vmparam.h 2140for the port-specific default. 2141.It Cd options DFLDSIZ=bytes 2142Sets the default size limit of a process' data segment, the value that 2143will be returned as the soft limit for 2144.Dv RLIMIT_DATA 2145(as returned by 2146.Xr getrlimit 2 ) . 2147See 2148.Pa /usr/include/machine/vmparam.h 2149for the port-specific default. 2150.It Cd options MAXDSIZ=bytes 2151Sets the maximum size limit of a process' data segment, the value that 2152will be returned as the hard limit for 2153.Dv RLIMIT_DATA 2154(as returned by 2155.Xr getrlimit 2 ) . 2156See 2157.Pa /usr/include/machine/vmparam.h 2158for the port-specific default. 2159.It Cd options DFLSSIZ=bytes 2160Sets the default size limit of a process' stack segment, the value that 2161will be returned as the soft limit for 2162.Dv RLIMIT_STACK 2163(as returned by 2164.Xr getrlimit 2 ) . 2165See 2166.Pa /usr/include/machine/vmparam.h 2167for the port-specific default. 2168.It Cd options MAXSSIZ=bytes 2169Sets the maximum size limit of a process' stack segment, the value that 2170will be returned as the hard limit for 2171.Dv RLIMIT_STACK 2172(as returned by 2173.Xr getrlimit 2 ) . 2174See 2175.Pa /usr/include/machine/vmparam.h 2176for the port-specific default. 2177.It Cd options DUMP_ON_PANIC=integer 2178Defaults to one. 2179If set to zero, the kernel will not dump to the dump device when 2180it panics, though dumps can still be forced via 2181.Xr ddb 4 2182with the 2183.Dq sync 2184command. 2185Note that this sets the value of the 2186.Em kern.dump_on_panic 2187.Xr sysctl 3 2188variable which may be changed at run time -- see 2189.Xr sysctl 8 2190for details. 2191.It Cd options USE_TOPDOWN_VM 2192User space memory allocations (as made by 2193.Xr mmap 2 ) 2194will be arranged in a 2195.Dq top down 2196fashion instead of the traditional 2197.Dq upwards from MAXDSIZ \&+ vm_daddr 2198method. 2199This includes the placement of 2200.Xr ld.so 1 . 2201Arranging memory in this manner allows either (or both of) the heap or 2202.Xr mmap 2 2203allocated space to grow larger than traditionally possible. 2204This option is not available on all ports, but is instead expected to be 2205offered on a port-by-port basis, after which some ports will commit to 2206using it by default. 2207See the files 2208.Pa /usr/include/uvm/uvm_param.h 2209for some implementation details, and 2210.Pa /usr/include/machine/vmparam.h 2211for port specific details including availability. 2212.It Cd options VMSWAP 2213Enable paging device/file support. 2214This option is on by default. 2215.It Cd options PDPOLICY_CLOCKPRO 2216Use CLOCK-Pro, an alternative page replace policy. 2217.El 2218.Ss Security Options 2219.Bl -ohang 2220.It Cd options INSECURE 2221Hardwires the kernel security level at \-1. 2222This means that the system 2223always runs in secure level \-1 mode, even when running multiuser. 2224See the manual page for 2225.Xr init 8 2226for details on the implications of this. 2227The kernel secure level may manipulated by the superuser by altering the 2228.Em kern.securelevel 2229.Xr sysctl 3 2230variable (the secure level may only be lowered by a call from process ID 1, 2231i.e., 2232.Xr init 8 ) . 2233See also 2234.Xr secmodel_securelevel 9 , 2235.Xr sysctl 8 2236and 2237.Xr sysctl 3 . 2238.It Cd options VERIFIED_EXEC_FP_MD5 2239Enables support for MD5 hashes in Veriexec. 2240.It Cd options VERIFIED_EXEC_FP_SHA1 2241Enables support for SHA1 hashes in Veriexec. 2242.It Cd options VERIFIED_EXEC_FP_RMD160 2243Enables support for RMD160 hashes in Veriexec. 2244.It Cd options VERIFIED_EXEC_FP_SHA256 2245Enables support for SHA256 hashes in Veriexec. 2246.It Cd options VERIFIED_EXEC_FP_SHA384 2247Enables support for SHA384 hashes in Veriexec. 2248.It Cd options VERIFIED_EXEC_FP_SHA512 2249Enables support for SHA512 hashes in Veriexec. 2250.It Cd options PAX_MPROTECT=value 2251Enables PaX MPROTECT, 2252.Xr mprotect 2 2253restrictions from the PaX project. 2254.Pp 2255The 2256.Ar value 2257is the default value for the 2258.Em global 2259knob, see 2260.Xr sysctl 3 . 2261If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2262using 2263.Xr paxctl 8 . 2264If 1, PaX MPROTECT will be enabled for all programs. 2265Programs can be exempted using 2266.Xr paxctl 8 . 2267.Pp 2268See 2269.Xr security 8 2270for more details. 2271.It Cd options PAX_SEGVGUARD=value 2272Enables PaX Segvguard. 2273.Pp 2274The 2275.Ar value 2276is the default value for the 2277.Em global 2278knob, see 2279.Xr sysctl 3 . 2280If 0, PaX Segvguard will be enabled only if explicitly set on programs 2281using 2282.Xr paxctl 8 . 2283If 1, PaX Segvguard will be enabled to all programs, and exemption can 2284be done using 2285.Xr paxctl 8 . 2286.Pp 2287See 2288.Xr security 8 2289for more details. 2290.It Cd options PAX_ASLR=value 2291Enables PaX ASLR. 2292.Pp 2293The 2294.Ar value 2295is the default value for the 2296.Em global 2297knob, see 2298.Xr sysctl 3 . 2299If 0, PaX ASLR will be enabled only if explicitly set on programs 2300using 2301.Xr paxctl 8 . 2302If 1, PaX ASLR will be enabled to all programs, and exemption can 2303be done using 2304.Xr paxctl 8 . 2305.Pp 2306See 2307.Xr security 8 2308for more details. 2309.El 2310.Ss amiga-specific Options 2311.Bl -ohang 2312.It Cd options BB060STUPIDROM 2313When the bootloader (which passes 2314.Tn AmigaOS 2315.Tn ROM 2316information) claims we have a 68060 2317.Tn CPU 2318without 2319.Tn FPU , 2320go look into the Processor Configuration Register (PCR) to find out. 2321You need this with 2322.Tn Amiga 2323.Tn ROM Ns s 2324up to (at least) V40.xxx (OS3.1), 2325when you boot via the bootblocks and don't have a DraCo. 2326.It Cd options IOBZCLOCK=frequency 2327The IOBlix boards come with two different serial master clocks: older ones 2328use 24 MHz, newer ones use 22.1184 MHz. 2329The driver normally assumes the latter. 2330If your board uses 24 MHz, you can recompile your kernel with 2331options IOBZCLOCK=24000000 2332or patch the kernel variable 2333.Tn iobzclock 2334to the same value. 2335.It Cd options LIMITMEM=value 2336If there, limit the part of the first memory bank used by 2337.Nx 2338to value megabytes. 2339Default is unlimited. 2340.It Cd options NKPTADD=addvalue 2341.It Cd options NKPTADDSHIFT=shiftvalue 2342The 2343.Tn CPU 2344specific 2345.Tn MMU 2346table for the kernel is pre-allocated at kernel startup time. 2347Part of it is scaled with 2348.Va maxproc , 2349to have enough room to hold the user program 2350.Tn MMU 2351tables; the second part is a fixed amount for the kernel itself. 2352.Pp 2353The third part accounts for the size of the file buffer cache. 2354Its size is either 2355.Dv NKPTADD 2356pages (if defined) or memory size in bytes divided by two to 2357the power of 2358.Dv NKPTADDSHIFT . 2359The default is undefined 2360.Dv NKPTADD 2361and 2362.Dv NKPTADDSHIFT=24 , 2363allowing for 16 buffers per megabyte of main memory (while 2364a GENERIC kernel allocates about half of that). 2365When you get "can't get KPT page" panics, you should increase 2366.Dv NKPTADD 2367(if defined), or decrease 2368.Dv NKPTADDSHIFT 2369by one. 2370.It Cd options P5PPC68KBOARD 2371Add special support for Phase5 mixed 68k+PPC boards. 2372Currently, this only affects rebooting from 2373.Nx 2374and is only needed on 68040+PPC, not on 237568060+PPC; without this, affected machines will hang after 2376.Nx 2377has shut 2378down and will only restart after a keyboard reset or a power cycle. 2379.El 2380.Ss arm32-specific Options 2381.Bl -ohang 2382.It Cd options FRENCH_KBD 2383Include translation for French keyboards when using 2384.Em pccons 2385on a Shark. 2386.It Cd options FINNISH_KBD 2387Include translation for Finnish keyboards when using 2388.Em pccons 2389on a Shark. 2390.It Cd options GERMAN_KBD 2391Include translation for German keyboards when using 2392.Em pccons 2393on a Shark. 2394.It Cd options NORWEGIAN_KBD 2395Include translation for French keyboards when using 2396.Em pccons 2397on a Shark. 2398.El 2399.Ss amd64-specific Options 2400.Bl -ohang 2401.It Cd options ENHANCED_SPEEDSTEP 2402Include support for the 2403.Tn Enhanced SpeedStep Technology 2404present in newer 2405.Tn CPU Ns s . 2406.It Cd options EST_FREQ_USERWRITE 2407Allow any user to change the frequency of an 2408.Tn Enhanced SpeedStep Technology 2409capable 2410.Tn CPU . 2411.It Cd options INTEL_ONDEMAND_CLOCKMOD 2412This enables the On Demand Clock Modulation by software 2413on Intel 2414.Tn CPUs 2415supporting the Thermal Monitor feature (TM). 2416You can select the duty cycle with 2417.Xr sysctl 8 2418in the node 2419.Em machdep.clockmod 2420if supported. 2421.It Cd options POWERNOW_K8 2422Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2423Technology, used to change the CPU voltage and frequency 2424on the fly. 2425.El 2426.Ss atari-specific Options 2427.Bl -ohang 2428.It Cd options DISKLABEL_AHDI 2429Include support for AHDI (native Atari) disklabels. 2430.It Cd options DISKLABEL_NBDA 2431Include support for 2432.Nx Ns Tn /atari 2433labels. 2434If you don't set this option, it will be set automatically. 2435.Nx Ns Tn /atari 2436will not work without it. 2437.It Cd options FALCON_SCSI 2438Include support for the 5380-SCSI configuration as found on the Falcon. 2439.It Cd options RELOC_KERNEL 2440If set, the kernel will relocate itself to TT-RAM, if possible. 2441This will give you a slightly faster system. 2442.Em Beware 2443that on some TT030 systems, 2444the system will frequently dump with MMU-faults with this option enabled. 2445.It Cd options SERCONSOLE 2446Allow the modem1-port to act as the system-console. 2447A carrier should be active on modem1 during system boot to active 2448the console functionality. 2449.It Cd options TT_SCSI 2450Include support for the 5380-SCSI configuration as found on the TT030 2451and Hades. 2452.El 2453.Ss i386-specific Options 2454.Bl -ohang 2455.It Cd options ENHANCED_SPEEDSTEP 2456Include support for the 2457.Tn Enhanced SpeedStep Technology 2458present in newer 2459.Tn CPU Ns s . 2460.It Cd options EST_FREQ_USERWRITE 2461Allow any user to change the frequency of an 2462.Tn Enhanced SpeedStep Technology 2463capable 2464.Tn CPU . 2465.It Cd options INTEL_ONDEMAND_CLOCKMOD 2466This enables the On Demand Clock Modulation by software 2467on Intel 2468.Tn CPUs 2469supporting the Thermal Monitor feature (TM). 2470You can select the duty cycle with 2471.Xr sysctl 8 2472in the node 2473.Em machdep.clockmod 2474if supported. 2475.It Cd options POWERNOW_K7 2476Include support for the AMD 2477.Tn PowerNow! Technology 2478present in AMD Athlon Mobile processors. 2479.It Cd options VIA_PADLOCK 2480Include support for the 2481.Tn AES 2482encryption instructions of the 2483.Tn VIA PadLock Security engine , 2484which is attached as a provider to the opencrypto framework. 2485.It Cd options CPURESET_DELAY=value 2486Specifies the time (in millisecond) to wait before doing a hardware reset 2487in the last phase of a reboot. 2488This gives the user a chance to see error messages from the shutdown 2489operations (like NFS unmounts, buffer cache flush, etc ...). 2490Setting this to 0 will disable the delay. 2491Default is 2 seconds. 2492.It Cd options VM86 2493Include support for virtual 8086 mode, used by 2494.Tn DOS 2495emulators and X servers to run BIOS code, e.g., for some VESA routines. 2496.It Cd options USER_LDT 2497Include i386-specific system calls for modifying the local descriptor table, 2498used by Windows emulators. 2499.It Cd options REALBASEMEM=integer 2500Overrides the base memory size passed in from the boot block. 2501(Value given in kilobytes.) 2502Use this option only if the boot block reports the size incorrectly. 2503(Note that some 2504.Tn BIOS Ns es 2505put the extended 2506.Tn BIOS 2507data area at the top of base memory, and therefore report a smaller 2508base memory size to prevent programs overwriting it. 2509This is correct behavior, and you should not use the 2510.Em REALBASEMEM 2511option to access this memory). 2512.It Cd options REALEXTMEM=integer 2513Overrides the extended memory size passed in from the boot block. 2514(Value given in kilobytes. 2515Extended memory does not include the first megabyte.) 2516Use this option only if the boot block reports the size incorrectly. 2517.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2518Select a non-US keyboard layout for the 2519.Em pccons 2520console driver. 2521.It Cd options CYRIX_CACHE_WORKS 2522Relevant only to the Cyrix 486DLC CPU. 2523This option is used to turn on the cache in hold-flush mode. 2524It is not turned on by default because it is known to have problems in 2525certain motherboard implementations. 2526.It Cd options CYRIX_CACHE_REALLY_WORKS 2527Relevant only to the Cyrix 486DLC CPU. 2528This option is used to turn on the cache in write-back mode. 2529It is not turned on by default because it is known to have problems in 2530certain motherboard implementations. 2531In order for this option to take effect, option 2532.Em CYRIX_CACHE_WORKS 2533must also be specified. 2534.It Cd options PCIBIOS 2535Enable support for initializing the 2536.Tn PCI 2537bus using information from the 2538.Tn BIOS . 2539See 2540.Xr pcibios 4 2541for details. 2542.It Cd options KSTACK_CHECK_DR0 2543Detect kernel stack overflow using DR0 register. 2544This option uses DR0 register exclusively so you can't use DR0 register for 2545other purpose (e.g., hardware breakpoint) if you turn this on. 2546.It Cd options MTRR 2547Include support for accessing MTRR registers from user-space. 2548See 2549.Xr i386_get_mtrr 2 . 2550.It Cd options BEEP_ONHALT 2551Make the system speaker emit several beeps when it is completely safe to 2552power down the computer after a 2553.Xr halt 8 2554command. 2555Requires 2556.Xr sysbeep 4 2557support. 2558.It Cd options BEEP_ONHALT_COUNT=times 2559Number of times to beep the speaker when 2560.Cd options BEEP_ONHALT 2561is enabled. 2562Defaults to 3. 2563.It Cd options BEEP_ONHALT_PITCH=hz 2564The tone frequency used when 2565.Cd options BEEP_ONHALT 2566option, in hertz. 2567Defaults to 1500. 2568.It Cd options BEEP_ONHALT_PERIOD=msecs 2569The duration of each beep when 2570.Cd options BEEP_ONHALT 2571is enabled, in milliseconds. 2572Defaults to 250. 2573.It Cd options MULTIBOOT 2574Makes the kernel Multiboot-compliant, allowing it to be booted through 2575a Multiboot-compliant boot manager such as GRUB. 2576See 2577.Xr multiboot 8 2578for more information. 2579.El 2580.Ss isa-specific Options 2581Options specific to 2582.Xr isa 4 2583busses. 2584.Bl -ohang 2585.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2586Control the section of IO bus space used for PCMCIA bus space mapping. 2587Ideally the probed defaults are satisfactory, however in practice 2588that is not always the case. 2589See 2590.Xr pcmcia 4 2591for details. 2592.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2593Controls the allowable interrupts that may be used for 2594.Tn PCMCIA 2595devices. 2596This mask is a logical-or of power-of-2s of allowable interrupts: 2597.Bd -literal -offset 04n 2598.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2599 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2600 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2601 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2602 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2603.Ed 2604.It Cd options PCKBC_CNATTACH_SELFTEST 2605Perform a self test of the keyboard controller before attaching it as a 2606console. 2607This might be necessary on machines where we boot on cold iron, and 2608pckbc refuses to talk until we request a self test. 2609Currently only the netwinder port uses it. 2610.It Cd options PCKBD_CNATTACH_MAY_FAIL 2611If this option is set the PS/2 keyboard will not be used as the console 2612if it cannot be found during boot. 2613This allows other keyboards, like USB, to be the console keyboard. 2614.It Cd options PCKBD_LAYOUT=layout 2615Sets the default keyboard layout, see 2616.Xr pckbd 4 . 2617.El 2618.Ss m68k-specific Options 2619.Bl -ohang 2620.It Cd options FPU_EMULATE 2621Include support for MC68881/MC68882 emulator. 2622.It Cd options FPSP 2623Include support for 68040 floating point. 2624.It Cd options M68020,M68030,M68040,M68060 2625Include support for a specific 2626.Tn CPU , 2627at least one (the one you are using) should be specified. 2628.It Cd options M060SP 2629Include software support for 68060. 2630This provides emulation of unimplemented 2631integer instructions as well as emulation of unimplemented floating point 2632instructions and data types and software support for floating point traps. 2633.El 2634.Ss powerpc-specific Options (OEA Only) 2635.Bl -ohang 2636.It Cd options PMAP_MEMLIMIT=value 2637Limit the amount of memory seen by the kernel to 2638.Ar value 2639bytes. 2640.It Cd options PTEGCOUNT=value 2641Specify the size of the page table as 2642.Ar value 2643PTE groups. 2644Normally, one PTEG is allocated per physical page frame. 2645.El 2646.Ss sparc-specific Options 2647.Bl -ohang 2648.It Cd options AUDIO_DEBUG 2649Enable simple event debugging of the logging of the 2650.Xr audio 4 2651device. 2652.It Cd options BLINK 2653Enable blinking of LED. 2654Blink rate is full cycle every N seconds for 2655N \*[Lt] then current load average. 2656See 2657.Xr getloadavg 3 . 2658.\" .It Cd options COLORFONT_CACHE 2659.\" What does this do? 2660.It Cd options COUNT_SW_LEFTOVERS 2661Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2662sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2663variables accessible from 2664.Xr ddb 4 . 2665See 2666.Xr sw 4 . 2667.It Cd options DEBUG_ALIGN 2668Adds debugging messages calls when user-requested alignment fault 2669handling happens. 2670.It Cd options DEBUG_EMUL 2671Adds debugging messages calls for emulated floating point and 2672alignment fixing operations. 2673.It Cd options DEBUG_SVR4 2674Prints registers messages calls for emulated SVR4 getcontext and 2675setcontext operations. 2676See 2677.Em options COMPAT_SVR4 . 2678.It Cd options EXTREME_DEBUG 2679Adds debugging functions callable from 2680.Xr ddb 4 . 2681The debug_pagetables, test_region and print_fe_map 2682functions print information about page tables for the SUN4M 2683platforms only. 2684.It Cd options EXTREME_EXTREME_DEBUG 2685Adds extra info to 2686.Em options EXTREME_DEBUG . 2687.It Cd options FPU_CONTEXT 2688Make 2689.Em options COMPAT_SVR4 2690getcontext and setcontext include floating point registers. 2691.It Cd options MAGMA_DEBUG 2692Adds debugging messages to the 2693.Xr magma 4 2694device. 2695.It Cd options RASTERCONS_FULLSCREEN 2696Use the entire screen for the console. 2697.It Cd options RASTERCONS_SMALLFONT 2698Use the Fixed font on the console, instead of the normal font. 2699.It Cd options SUN4 2700Support sun4 class machines. 2701.It Cd options SUN4C 2702Support sun4c class machines. 2703.It Cd options SUN4M 2704Support sun4m class machines. 2705.It Cd options SUN4_MMU3L 2706.\" XXX ??? 2707Enable support for sun4 3-level MMU machines. 2708.It Cd options V9 2709Enable SPARC V9 assembler in 2710.Xr ddb 4 . 2711.El 2712.Ss sparc64-specific Options 2713.Bl -ohang 2714.It Cd options AUDIO_DEBUG 2715Enable simple event debugging of the logging of the 2716.Xr audio 4 2717device. 2718.It Cd options BLINK 2719Enable blinking of LED. 2720Blink rate is full cycle every N seconds for 2721N \*[Lt] then current load average. 2722See 2723.Xr getloadavg 3 . 2724.El 2725.Ss x68k-specific Options 2726.Bl -ohang 2727.It Cd options EXTENDED_MEMORY 2728Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2729.It Cd options JUPITER 2730Include support for Jupiter-X MPU accelerator 2731.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2732Use the built-in serial port as the system-console. 2733Speed is specified in bps, defaults to 9600. 2734.It Cd options ITE_KERNEL_ATTR=value 2735Set the kernel message attribute for ITE. 2736Value, an integer, is a logical or of the following values: 2737.Bl -tag -width 4n -compact -offset indent 2738.It 1 2739color inversed 2740.It 2 2741underlined 2742.It 4 2743bolded 2744.El 2745.El 2746.\" The following requests should be uncommented and used where appropriate. 2747.\" .Sh FILES 2748.\" .Sh EXAMPLES 2749.Sh SEE ALSO 2750.Xr config 1 , 2751.Xr gdb 1 , 2752.Xr ktrace 1 , 2753.Xr pmc 1 , 2754.Xr quota 1 , 2755.Xr vndcompress 1 , 2756.Xr gettimeofday 2 , 2757.Xr i386_get_mtrr 2 , 2758.Xr i386_iopl 2 , 2759.Xr msgctl 2 , 2760.Xr msgget 2 , 2761.Xr msgrcv 2 , 2762.Xr msgsnd 2 , 2763.Xr ntp_adjtime 2 , 2764.Xr ntp_gettime 2 , 2765.Xr reboot 2 , 2766.Xr semctl 2 , 2767.Xr semget 2 , 2768.Xr semop 2 , 2769.Xr shmat 2 , 2770.Xr shmctl 2 , 2771.Xr shmdt 2 , 2772.Xr shmget 2 , 2773.Xr sysctl 3 , 2774.Xr apm 4 , 2775.Xr ddb 4 , 2776.Xr inet 4 , 2777.Xr iso 4 , 2778.Xr md 4 , 2779.Xr ns 4 , 2780.Xr pcibios 4 , 2781.Xr pcmcia 4 , 2782.Xr ppp 4 , 2783.Xr userconf 4 , 2784.Xr vnd 4 , 2785.Xr wscons 4 , 2786.Xr config 5 , 2787.Xr edquota 8 , 2788.Xr init 8 , 2789.Xr mdsetimage 8 , 2790.Xr mount_cd9660 8 , 2791.Xr mount_fdesc 8 , 2792.Xr mount_kernfs 8 , 2793.Xr mount_lfs 8 , 2794.Xr mount_mfs 8 , 2795.Xr mount_msdos 8 , 2796.Xr mount_nfs 8 , 2797.Xr mount_ntfs 8 , 2798.Xr mount_null 8 , 2799.Xr mount_portal 8 , 2800.Xr mount_procfs 8 , 2801.Xr mount_udf 8 , 2802.Xr mount_umap 8 , 2803.Xr mount_union 8 , 2804.Xr mrouted 8 , 2805.Xr newfs_lfs 8 , 2806.Xr ntpd 8 , 2807.Xr quotaon 8 , 2808.Xr rpc.rquotad 8 , 2809.Xr sysctl 8 , 2810.Xr in_getifa 9 2811.Sh HISTORY 2812The 2813.Nm 2814man page first appeared in 2815.Nx 1.3 . 2816.Sh BUGS 2817The 2818.Em EON 2819option should be a pseudo-device, and is also very fragile. 2820