1.\" $NetBSD: options.4,v 1.371 2008/11/12 12:35:53 ad 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 November 12, 2008 34.Os 35.Dt OPTIONS 4 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Xo 66.Qq Ar filename 67.Xc 68Conditionally includes another kernel configuration file whose name is 69.Ar filename , 70which may be double-quoted and may be an explicit path or relative to 71the kernel source directory. 72Failure to open the named file is ignored. 73.It Sy config Xo 74.Ar exec_name 75.No root on 76.Ar rootdev 77.Op type Ar fstype 78.Op dumps on Ar dumpdev 79.Xc 80Defines a configuration whose kernel executable is named 81.Ar exec_name , 82normally 83.Dq netbsd , 84with its root file system of type 85.Ar fstype 86on the device 87.Ar rootdev , 88and optionally specifying the location of kernel core dumps on the device 89.Ar dumpdev . 90.Ar dev 91or 92.Ar dumpdev 93and 94.Ar fstype 95may be specified as 96.Dq \&? , 97which is a wild card. 98The root 99.Ar fstype 100and 101.Ar dumpdev 102are optional and assumed to be wild carded if they are not specified. 103.It Ar device_instance Xo 104at 105.Ar attachment 106.Op Ar locators value Op ... 107.Op flags Ar value 108.Xc 109Define an instance of the device driver 110.Ar device_instance 111that attaches to the bus or device named 112.Ar attachment . 113An 114.Ar attachment 115may require additional information on where the device can be found, such 116as an address, channel, function, offset, and/or slot, referred to as 117.Ar locators , 118whose 119.Ar value 120often may be a wild card, 121.Dq \&? . 122Some device drivers have one or more 123.Ar flags 124that can be adjusted to affect the way they operate. 125.It Sy file-system Xo 126.Ar fs_name Op , Ar fs_name Op ... 127.Xc 128Include support for the file-system 129.Ar fs_name . 130.It Sy ident Xo 131.Qq Ar string 132.Xc 133Sets the kernel identification string to 134.Ar string . 135.It Sy include Xo 136.Qq Ar filename 137.Xc 138Functions the same as 139.Ar cinclude , 140except failure to open 141.Ar filename 142produces a fatal error. 143.It Sy options Xo 144.Ar option_name Op , Ar option_name=value Op ... 145.Xc 146Specifies (or sets) the option, or comma-separated list of options, 147.Ar option_name . 148Some options expect to be assigned a value, which may be an integer, 149a double-quoted word, a bare word, or an empty string 150.Pq Qq . 151Note that those are eventually handled by the C compiler, so the rules 152of that language apply. 153.Pp 154.Em Note : 155Options that are not defined by device definition files are passed to 156the compile process as 157.Fl D 158flags to the C compiler. 159.It Sy makeoptions Xo 160.Ar name=value 161.Xc 162Defines a 163.Xr make 1 164macro 165.Ar name 166with the value 167.Ar value 168in the kernel Makefile. 169.It Sy maxusers Xo 170.Ar integer 171.Xc 172Set the maxusers variable in the kernel. 173.It Sy no Xo 174.Ar keyword Ar name Op Ar arguments Op ... 175.Xc 176For the 177.Xr config 1 178.Ar keywords 179file-system, makeoptions, options, and pseudo-device, 180.Ar no 181removes the file-system, makeoption, options, or pseudo-device, 182.Ar name . 183This is useful when a kernel configuration file includes another which 184has undesired options. 185.Pp 186For example, a local configuration file that wanted the kitchen sink, but 187not COMPAT_09 or bridging, might be: 188.Bd -literal -offset indent 189include "arch/i386/conf/GENERIC" 190no options COMPAT_09 191no pseudo-device bridge 192.Ed 193.It Sy pseudo-device Xo 194.Ar name 195.Op Ar N 196.Xc 197Includes support for the pseudo-device 198.Ar name . 199Some pseudo-devices can have multiple or 200.Ar N 201instances. 202.El 203.Ss Compatibility Options 204.Bl -ohang 205.It Cd options COMPAT_09 206Enable binary compatibility with 207.Nx 0.9 . 208This enables support for 20916-bit user, group, and process IDs (following revisions support 21032-bit identifiers). 211It also allows the use of the deprecated 212.Xr getdomainname 3 , 213.Xr setdomainname 3 , 214and 215.Xr uname 3 216syscalls. 217This option also allows using numeric file system identifiers rather 218than strings. 219Post 220.Nx 0.9 221versions use string identifiers. 222.It Cd options COMPAT_10 223Enable binary compatibility with 224.Nx 1.0 . 225This option allows the use of the file system name of 226.Dq ufs 227as an alias for 228.Dq ffs . 229The name 230.Dq ffs 231should be used post 1.0 in 232.Pa /etc/fstab 233and other files. 234It also adds old syscalls for the 235.At V 236shared memory interface. 237This was changed post 1.0 to work on 64-bit architectures. 238This option also enables 239.Dq sgtty 240compatibility, without which programs using the old interface produce 241an 242.Dq inappropriate ioctl 243error, and 244.Pa /dev/io 245only works when this option is set in the kernel, 246see 247.Xr io 4 248on ports that support it. 249.It Cd options COMPAT_11 250Enable binary compatibility with 251.Nx 1.1 . 252This allows binaries running on the i386 port to gain direct access to 253the io ports by opening 254.Pa /dev/io 255read/write. 256This functionality was replaced by 257.Xr i386_iopl 2 258post 1.1. 259On the 260.Tn Atari 261port, the location of the disk label was moved after 1.1. 262When the 263.Em COMPAT_11 264option is set, the kernel will read (pre) 1.1 style disk labels as a 265last resort. 266When a disk label is re-written, the old style label will be replaced 267with a post 1.1 style label. 268This also enables the 269.Em EXEC_ELF_NOTELESS 270option. 271.It Cd options COMPAT_12 272Enable binary compatibility with 273.Nx 1.2 . 274This allows the use of old syscalls for 275.Fn reboot 276and 277.Fn swapon . 278The syscall numbers were changed post 1.2 to add functionality to the 279.Xr reboot 2 280syscall, and the new 281.Xr swapctl 2 282interface was introduced. 283This also enables the 284.Em EXEC_ELF_NOTELESS 285option. 286.It Cd options COMPAT_13 287Enable binary compatibility with 288.Nx 1.3 . 289This allows the use of old syscalls for 290.Fn sigaltstack , 291and also enables the old 292.Xr swapctl 2 293command 294.Dv SWAP_STATS 295(now called 296.Dv SWAP_OSTATS ) , 297which does not include the 298.Fa se_path 299member of 300.Va struct swapent . 301.It Cd options COMPAT_14 302Enable binary compatibility with 303.Nx 1.4 . 304This allows some old 305.Xr ioctl 2 306on 307.Xr wscons 4 308to be performed, and allows the 309.Dv NFSSVC_BIOD 310mode of the 311.Xr nfssvc 2 312system call to be used for compatibility with the deprecated nfsiod program. 313.It Cd options COMPAT_15 314Enable binary compatibility with 315.Nx 1.5 . 316Since there were no API changes from 317.Nx 1.5 318and 319.Nx 1.6 , 320this option does nothing. 321.It Cd options COMPAT_16 322Enable binary compatibility with 323.Nx 1.6 . 324This allows the use of old signal trampoline code which has been deprecated 325with the addition of 326.Xr siginfo 2 . 327.It Cd options COMPAT_20 328Enable binary compatibility with 329.Nx 2.0 . 330This allows the use of old syscalls for 331.Fn statfs , 332.Fn fstatfs , 333.Fn getfsstat 334and 335.Fn fhstatfs , 336which have been deprecated with the addition of the 337.Xr statvfs 2 , 338.Xr fstatvfs 2 , 339.Xr getvfsstat 2 340and 341.Xr fhstatvfs 2 342system calls. 343.It Cd options COMPAT_30 344Enable binary compatibility with 345.Nx 3.0 . 346See 347.Xr compat_30 8 348for details about the changes made after the 349.Nx 3.0 350release. 351.It Cd options COMPAT_43 352Enables compatibility with 353.Bx 4.3 . 354This adds an old syscall for 355.Xr lseek 2 . 356It also adds the ioctls for 357.Dv TIOCGETP 358and 359.Dv TIOCSETP . 360The return values for 361.Xr getpid 2 , 362.Xr getgid 2 , 363and 364.Xr getuid 2 365syscalls are modified as well, to return the parent's PID and 366UID as well as the current process's. 367It also enables the deprecated 368.Dv NTTYDISC 369terminal line discipline. 370It also provides backwards compatibility with 371.Dq old 372SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 373binary compatibility with code written before the introduction of the 374sa_len field in sockaddrs. 375It also enables 376support for some older pre 377.Bx 4.4 378socket calls. 379.It Cd options COMPAT_BSDPTY 380This option is currently on by default and enables the pty multiplexer 381.Xr ptm 4 382and 383.Xr ptmx 4 384to find and use ptys named 385.Pa /dev/ptyXX 386(master) and 387.Pa /dev/ttyXX 388(slave). 389Eventually this option will become optional as ptyfs based pseudo-ttys become 390the default, see 391.Xr mount_ptyfs 8 . 392.It Cd options COMPAT_SVR4 393On those architectures that support it, this enables binary 394compatibility with 395.At V.4 396applications built for the same architecture. 397This currently includes the i386, m68k, and sparc ports. 398.It Cd options COMPAT_LINUX 399On those architectures that support it, this enables binary 400compatibility with Linux ELF and 401.Xr a.out 5 402applications built for the same architecture. 403This currently includes the alpha, arm, i386, m68k, mips, powerpc and 404x86_64 ports. 405.It Cd options COMPAT_LINUX32 406On those 64 bit architectures that support it, this enables binary 407compatibility with 32 bit Linux binaries. 408For now this is limited to running i386 ELF Linux binaries on amd64. 409.It Cd options COMPAT_SUNOS 410On those architectures that support it, this enables binary 411compatibility with 412.Tn SunOS 4.1 413applications built for the same architecture. 414This currently includes the sparc, sparc64 and most or all m68k ports. 415Note that the sparc64 requires the 416.Em COMPAT_NETBSD32 417option for 64-bit kernels, in addition to this option. 418.It Cd options COMPAT_ULTRIX 419On those architectures that support it, this enables binary 420compatibility with 421.Tn ULTRIX 422applications built for the same architecture. 423This currently is limited to the pmax. 424The functionality of this option is unknown. 425.It Cd options COMPAT_DARWIN 426On those architectures that support it, this enables binary compatibility with 427.Tn Darwin 428applications built for the same architecture. 429This feature is highly experimental, it requires COMPAT_MACH and 430EXEC_MACHO and it is currently limited to i386 and powerpc ports of 431.Nx . 432.It Cd options COMPAT_FREEBSD 433On those architectures that support it, this enables binary 434compatibility with 435.Fx 436applications built for the same architecture. 437At the moment this is limited to the i386 port. 438.It Cd options COMPAT_IBCS2 439On those architectures that support it, this enables binary 440compatibility with iBCS2 or SVR3 applications built for the same architecture. 441This is currently limited to the i386 and vax ports. 442.It Cd options COMPAT_IRIX 443On those architectures that support it, this enables binary 444compatibility with IRIX o32 binaries built for the same architecture. 445This feature is experimental, and it is currently limited to 446the sgimips port. 447.It Cd options COMPAT_MACH 448On those architectures that support it, this enables the emulation of 449Mach kernel traps for binaries built for the same architecture. 450This feature is highly experimental and it is currently 451limited to the i386 and powerpc ports of 452.Nx . 453.It Cd options COMPAT_OSF1 454On those architectures that support it, this enables binary 455compatibility with 456.Tn Digital 457.Ux 458.Po 459formerly 460.Tn OSF/1 461.Pc 462applications built for the same architecture. 463This is currently limited to the alpha port. 464.It Cd options COMPAT_NOMID 465Enable compatibility with 466.Xr a.out 5 467executables that lack a machine ID. 468This includes 469.Nx 0.8 Ns 's 470ZMAGIC format, and 386BSD and BSDI's 471QMAGIC, NMAGIC, and OMAGIC 472.Xr a.out 5 473formats. 474.It Cd options COMPAT_NETBSD32 475On those architectures that support it, this enables binary 476compatibility with 32-bit applications built for the same architecture. 477This is currently limited to the amd64 and sparc64 ports, and only 478applicable for 64-bit kernels. 479.It Cd options COMPAT_SVR4_32 480On those architectures that support it, this enables binary 481compatibility with 32-bit SVR4 applications built for the same architecture. 482This is currently limited to the sparc64 port, and only applicable for 48364-bit kernels. 484.It Cd options COMPAT_AOUT_M68K 485On m68k architectures which have switched to ELF, 486this enables binary compatibility with 487.Nx Ns Tn /m68k 488.Xr a.out 5 489executables on 490.Nx Ns Tn /m68k 491ELF kernels. 492This handles alignment incompatibility of m68k ABI between 493a.out and ELF which causes the structure padding differences. 494Currently only some system calls which use 495.Va struct stat 496are adjusted and some binaries which use 497.Xr sysctl 3 498to retrieve network details would not work properly. 499.It Cd options EXEC_MACHO 500On those architectures that support it, this adds support for running 501Mach-O executables. 502This is currently limited to the i386 and powerpc ports of 503.Nx . 504.It Cd options EXEC_ELF_NOTELESS 505Run unidentified ELF binaries as 506.Nx 507binaries. 508This might be needed for very old 509.Nx 510ELF binaries on some archs. 511These old binaries didn't contain an appropriate 512.Li .note.netbsd.ident 513section, and thus can't be identified by the kernel as 514.Nx 515binaries otherwise. 516Beware - if this option is on, the kernel would run 517.Em any 518unknown ELF binaries as if they were 519.Nx 520binaries. 521.It Cd options P1003_1B_SEMAPHORE 522Includes kernel support for the standard C library 523.Pq libc 524functions that implement semaphores as specified in 525.St -p1003.1-96 . 526.El 527.Ss Debugging Options 528.Bl -ohang 529.It Cd options DDB 530Compiles in a kernel debugger for diagnosing kernel problems. 531See 532.Xr ddb 4 533for details. 534.Em NOTE : 535not available on all architectures. 536.It Cd options DDB_FROMCONSOLE=integer 537If set to non-zero, DDB may be entered by sending a break on a serial 538console or by a special key sequence on a graphics console. 539A value of "0" ignores console breaks or key sequences. 540If not explicitly specified, the default value is "1". 541Note that this sets the value of the 542.Em ddb.fromconsole 543.Xr sysctl 3 544variable which may be changed at run time -- see 545.Xr sysctl 8 546for details. 547.It Cd options DDB_HISTORY_SIZE=integer 548If this is non-zero, enable history editing in the kernel debugger 549and set the size of the history to this value. 550.It Cd options DDB_ONPANIC 551The default if not specified is 552.Dq 1 553- just enter into DDB. 554If set to 555.Dq 2 556the kernel will 557attempt to print out a stack trace before entering into DDB. 558If set to 559.Dq 0 560the kernel will attempt to print out a stack trace 561and reboot the system. 562If set to 563.Dq -1 564then neither a stack trace is printed or DDB entered - 565it is as if DDB were not compiled into the kernel. 566Note that this sets the value of the 567.Em ddb.onpanic 568.Xr sysctl 3 569variable which may be changed at run time -- see 570.Xr sysctl 8 571for details. 572.It Cd options DDB_COMMANDONENTER=string 573This option specify commands which will be executed on each entry to DDB. 574This sets the default value of the 575.Em ddb.commandonenter 576.Xr sysctl 3 577variable which may be changed at run time. 578.It Cd options DDB_BREAK_CHAR=integer 579This option overrides using break to enter the kernel debugger 580on the serial console. 581The value given is the ASCII value to be used instead. 582This is currently only supported by the com driver. 583.It Cd options DDB_VERBOSE_HELP 584This option adds more verbose descriptions to the 585.Em help 586command. 587.It Cd options KGDB 588Compiles in a remote kernel debugger stub for diagnosing kernel problems 589using the 590.Dq remote target 591feature of gdb. 592See 593.Xr gdb 1 594for details. 595.Em NOTE : 596not available on all architectures. 597.It Cd options KGDB_DEV 598Device number 599.Po 600as a 601.Dv dev_t 602.Pc 603of kgdb device. 604.It Cd options KGDB_DEVADDR 605Memory address of kgdb device. 606.It Cd options KGDB_DEVMODE 607Permissions of kgdb device. 608.It Cd options KGDB_DEVNAME 609Device name of kgdb device. 610.It Cd options KGDB_DEVRATE 611Baud rate of kgdb device. 612.It Cd makeoptions DEBUG="-g" 613The 614.Fl g 615flag causes 616.Pa netbsd.gdb 617to be built in addition to 618.Pa netbsd . 619.Pa netbsd.gdb 620is useful for debugging kernel crash dumps with gdb. 621See 622.Xr gdb 1 623for details. 624This also turns on 625.Em options DEBUG 626(which see). 627.It Cd options DEBUG 628Turns on miscellaneous kernel debugging. 629Since options are turned into preprocessor defines (see above), 630.Em options DEBUG 631is equivalent to doing a 632.Em #define DEBUG 633throughout the kernel. 634Much of the kernel has 635.Em #ifdef DEBUG 636conditionalized debugging code. 637Note that many parts of the kernel (typically device drivers) include their own 638.Em #ifdef XXX_DEBUG 639conditionals instead. 640This option also turns on certain other options, 641which may decrease system performance. 642.It Cd options DIAGNOSTIC 643Adds code to the kernel that does internal consistency checks. 644This code will cause the kernel to panic if corruption of internal data 645structures is detected. 646These checks can decrease performance up to 15%. 647.It Cd options KSTACK_CHECK_MAGIC 648Check kernel stack usage and panic if stack overflow is detected. 649This check is performance sensitive because it scans stack on each context 650switch. 651.It Cd options KTRACE 652Add hooks for the system call tracing facility, which allows users to 653watch the system call invocation behavior of processes. 654See 655.Xr ktrace 1 656for details. 657.It Cd options MSGBUFSIZE=integer 658This option sets the size of the kernel message buffer. 659This buffer holds the kernel output of 660.Fn printf 661when not (yet) read by 662.Xr syslogd 8 . 663This is particularly useful when the system has crashed and you wish to lookup 664the kernel output from just before the crash. 665Also, since the autoconfig output becomes more and more verbose, 666it sometimes happens that the message buffer overflows before 667.Xr syslogd 8 668was able to read it. 669Note that not all systems are capable of obtaining a variable sized message 670buffer. 671There are also some systems on which memory contents are not preserved 672across reboots. 673.It Cd options MALLOCLOG 674Enables an event log for 675.Xr malloc 9 . 676Useful for tracking down 677.Dq Data modified on freelist 678and 679.Dq multiple free 680problems. 681.It Cd options MALLOCLOGSIZE=integer 682Defines the number of entries in the malloc log. 683Default is 100000 entries. 684.It Cd options UVMHIST 685Enables the UVM history logs, which create in-memory traces of 686various UVM activities. 687These logs can be displayed be calling 688.Fn uvmhist_dump 689or 690.Fn uvm_hist 691with appropriate arguments from DDB. 692See the kernel source file sys/uvm/uvm_stat.c for details. 693.It Cd options UVMHIST_PRINT 694Prints the UVM history logs on the system console as entries are added. 695Note that the output is 696.Em extremely 697voluminous, so this option is really only useful for debugging 698the very earliest parts of kernel initialization. 699.El 700.Ss File Systems 701.Bl -ohang 702.It Cd file-system FFS 703Includes code implementing the Berkeley Fast File System 704.Em ( FFS ) . 705Most machines need this if they are not running diskless. 706.It Cd file-system EXT2FS 707Includes code implementing the Second Extended File System 708.Em ( EXT2FS ) , 709revision 0 and revision 1 with the 710.Em filetype 711and 712.Em sparse_super 713options. 714This is the most commonly used file system on the Linux operating system, 715and is provided here for compatibility. 716Some of the specific features of 717.Em EXT2FS 718like the "behavior on errors" are not implemented. 719This file system can't be used with UID or GID greater than 65535. 720See 721.Xr mount_ext2fs 8 722for details. 723.It Cd file-system LFS 724.Bq Em EXPERIMENTAL 725Include the Log-structured File System 726.Em ( LFS ) . 727See 728.Xr mount_lfs 8 729and 730.Xr newfs_lfs 8 731for details. 732.It Cd file-system MFS 733Include the Memory File System 734.Em ( MFS ) . 735This file system stores files in swappable memory, and produces 736notable performance improvements when it is used as the file store 737for 738.Pa /tmp 739and similar file systems. 740See 741.Xr mount_mfs 8 742for details. 743.It Cd file-system NFS 744Include the client side of the Network File System 745.Pq Tn NFS 746remote file sharing protocol. 747Although the bulk of the code implementing 748.Tn NFS 749is kernel based, several user level daemons are needed for it to work. 750See 751.Xr mount_nfs 8 752for details. 753.It Cd file-system CD9660 754Includes code for the 755.Tn ISO 7569660 + Rock Ridge file system, which is the standard file system on many 757.Tn CD-ROM 758discs. 759Useful primarily if you have a 760.Tn CD-ROM 761drive. 762See 763.Xr mount_cd9660 8 764for details. 765.It Cd file-system MSDOSFS 766Includes the 767.Tn MS-DOS 768FAT file system, which is reportedly still used 769by unfortunate people who have not heard about 770.Nx . 771Also implements the 772.Tn Windows 95 773extensions to the same, which permit the use of longer, mixed case 774file names. 775See 776.Xr mount_msdos 8 777and 778.Xr fsck_msdos 8 779for details. 780.It Cd file-system NTFS 781.Bq Em EXPERIMENTAL 782Includes code for the 783.Tn Microsoft Windows NT 784file system. 785See 786.Xr mount_ntfs 8 787for details. 788.It Cd file-system FDESC 789Includes code for a file system, conventionally mounted on 790.Pa /dev/fd , 791which permits access to the per-process file descriptor space via 792special files in the file system. 793See 794.Xr mount_fdesc 8 795for details. 796Note that this facility is redundant, and thus unneeded on most 797.Nx 798systems, since the 799.Xr fd 4 800pseudo-device driver already provides identical functionality. 801On most 802.Nx 803systems, instances of 804.Xr fd 4 805are mknoded under 806.Pa /dev/fd/ 807and on 808.Pa /dev/stdin , 809.Pa /dev/stdout , 810and 811.Pa /dev/stderr . 812.It Cd file-system KERNFS 813Includes code which permits the mounting of a special file system 814(normally mounted on 815.Pa /kern ) 816in which files representing various kernel variables and parameters 817may be found. 818See 819.Xr mount_kernfs 8 820for details. 821.It Cd file-system NULLFS 822Includes code for a loopback file system. 823This permits portions of the file hierarchy to be re-mounted in other places. 824The code really exists to provide an example of a stackable file system layer. 825See 826.Xr mount_null 8 827for details. 828.It Cd file-system OVERLAY 829Includes code for a file system filter. 830This permits the overlay file system to intercept all access to an underlying 831file system. 832This file system is intended to serve as an example of a stacking file 833system which has a need to interpose itself between an underlying file 834system and all other access. 835See 836.Xr mount_overlay 8 837for details. 838.It Cd file-system PORTAL 839.Bq Em EXPERIMENTAL 840Includes the portal file system. 841This permits interesting tricks like opening 842.Tn TCP 843sockets by opening files in the file system. 844The portal file system is conventionally mounted on 845.Pa /p 846and is partially implemented by a special daemon. 847See 848.Xr mount_portal 8 849for details. 850.It Cd file-system PROCFS 851Includes code for a special file system (conventionally mounted on 852.Pa /proc ) 853in which the process space becomes visible in the file system. 854Among 855other things, the memory spaces of processes running on the system are 856visible as files, and signals may be sent to processes by writing to 857.Pa ctl 858files in the procfs namespace. 859See 860.Xr mount_procfs 8 861for details. 862.It Cd file-system UDF 863.Bq Em EXPERIMENTAL 864Includes code for the UDF file system commonly found on CD and DVD 865media but also more and more on USB sticks. 866Useful primarily if you have a CD or a DVD drive, be it a read-only 867or a rewritable device. 868Currently only supports read-access. 869See 870.Xr mount_udf 8 871for details. 872.It Cd file-system UMAPFS 873Includes a loopback file system in which user and group IDs may be 874remapped -- this can be useful when mounting alien file systems with 875different UIDs and GIDs than the local system. 876See 877.Xr mount_umap 8 878for details. 879.It Cd file-system UNION 880.Bq Em EXPERIMENTAL 881Includes code for the union file system, which permits directories to 882be mounted on top of each other in such a way that both file systems 883remain visible -- this permits tricks like allowing writing (and the 884deleting of files) on a read-only file system like a 885.Tn CD-ROM 886by mounting a local writable file system on top of the read-only file system. 887See 888.Xr mount_union 8 889for details. 890.It Cd file-system CODA 891.Bq Em EXPERIMENTAL 892Includes code for the Coda file system. 893Coda is a distributed file system like NFS and AFS. 894It is freely available, like NFS, but it functions much like AFS in being a 895.Dq stateful 896file system. 897Both Coda and AFS cache files on your local machine to improve performance. 898Then Coda goes a step further than AFS by letting you access the cached 899files when there is no available network, viz. disconnected laptops and 900network outages. 901In Coda, both the client and server are outside the kernel which makes 902them easier to experiment with. 903Coda is available for several UNIX and non-UNIX platforms. 904See http://www.coda.cs.cmu.edu for more details. 905.Em NOTE : 906You also need to enable the pseudo-device, vcoda, for the Coda 907file system to work. 908.It Cd file-system SMBFS 909.Bq Em EXPERIMENTAL 910Includes code for the SMB/CIFS file system. 911See 912.Xr mount_smbfs 8 913for details. 914.Em NOTE : 915You also need to enable the pseudo-device, nsmb, for the SMB 916file system to work. 917.It Cd file-system PTYFS 918.Bq Em EXPERIMENTAL 919Includes code for a special file system (normally mounted on 920.Pa /dev/pts ) 921in which pseudo-terminal slave devices become visible in the file system. 922See 923.Xr mount_ptyfs 8 924for details. 925.It Cd file-system TMPFS 926Includes code for the efficient memory file system, normally used over 927.Pa /tmp . 928See 929.Xr mount_tmpfs 8 930for details. 931.It Cd file-system PUFFS 932.Bq Em EXPERIMENTAL 933Includes kernel support for the pass-to-userspace framework file system. 934It can be used to implement file system functionality in userspace. 935See 936.Xr puffs 3 937and 938.Xr puffs 4 939for more details. 940This option is required for sshfs: 941.Xr mount_psshfs 8 . 942.El 943.Ss File System Options 944.Bl -ohang 945.It Cd options MAGICLINKS 946Enables the expansion of special strings 947.Po 948beginning with 949.Dq @ 950.Pc 951when traversing symbolic links. 952See 953.Xr symlink 7 954for a list of supported strings. 955Note that this option only controls the enabling of this feature 956by the kernel at boot-up. 957This feature can still be manipulated with the 958.Xr sysctl 8 959command regardless of the setting of this option. 960.It Cd options NFSSERVER 961Include the server side of the 962.Em NFS 963(Network File System) remote file sharing protocol. 964Although the bulk of the code implementing 965.Em NFS 966is kernel based, several user level daemons are needed for it to 967work. 968See 969.Xr mountd 8 970and 971.Xr nfsd 8 972for details. 973.It Cd options QUOTA 974Enables kernel support for file system quotas. 975See 976.Xr quotaon 8 , 977.Xr edquota 8 , 978and 979.Xr quota 1 980for details. 981Note that quotas only work on 982.Dq ffs 983file systems, although 984.Xr rpc.rquotad 8 985permits them to be accessed over 986.Em NFS . 987.It Cd options FFS_EI 988Enable ``Endian-Independent'' FFS support. 989This allows a system to mount an FFS file system created for another 990architecture, at a small performance cost for all FFS file systems. 991See also 992.Xr newfs 8 , 993.Xr fsck_ffs 8 , 994.Xr dumpfs 8 995for file system byte order status and manipulation. 996.It Cd options FFS_NO_SNAPSHOT 997Disable the 998.Dq file system snapshot 999support in FFS file systems. 1000Maybe useful for install media kernels, small memory systems and 1001embedded systems which don't require the snapshot support. 1002.It Cd options WAPBL 1003Enable 1004.Dq Write Ahead Physical Block Logging file system journaling . 1005This provides rapid file system consistency checking after a system outage. 1006It also provides better general use performance over regular FFS. 1007See also 1008.Xr wapbl 4 . 1009.It Cd options NVNODE=integer 1010This option sets the size of the cache used by the name-to-inode translation 1011routines, (a.k.a. the 1012.Fn namei 1013cache, though called by many other names in the kernel source). 1014By default, this cache has 1015.Dv NPROC 1016(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 1017A reasonable way to derive a value of 1018.Dv NVNODE , 1019should you notice a large number of namei cache misses with a tool such as 1020.Xr systat 1 , 1021is to examine your system's current computed value with 1022.Xr sysctl 8 , 1023(which calls this parameter "kern.maxvnodes") and to increase this value 1024until either the namei cache hit rate improves or it is determined that 1025your system does not benefit substantially from an increase in the size of 1026the namei cache. 1027.It Cd options NAMECACHE_ENTER_REVERSE 1028Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1029as well as a normal one. 1030Normally, this is already done for directory vnodes, to speed up the getcwd 1031operation. 1032This option will cause longer hash chains in the reverse cache, and thus 1033slow down getcwd somewhat. 1034However, it does make vnode -\*[Gt] path translations possible in some cases. 1035For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1036required. 1037.It Cd options EXT2FS_SYSTEM_FLAGS 1038This option changes the behavior of the APPEND and IMMUTABLE flags 1039for a file on an 1040.Em EXT2FS 1041file system. 1042Without this option, the superuser or owner of the file can 1043set and clear them. 1044With this option, only the superuser can set them, and 1045they can't be cleared if the securelevel is greater than 0. 1046See also 1047.Xr chflags 1 1048and 1049.Xr secmodel_securelevel 9 . 1050.It Cd options NFS_BOOT_BOOTP 1051Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1052information if NFS is used to mount the root file system. 1053See 1054.Xr diskless 8 1055for details. 1056.It Cd options NFS_BOOT_DHCP 1057Same as 1058.Dq NFS_BOOT_BOOTP , 1059but use the DHCP extensions to the 1060BOOTP protocol (RFC 1541). 1061.It Cd options NFS_BOOT_BOOTP_REQFILE 1062Specifies the string sent in the bp_file field of the BOOTP / DHCP 1063request packet. 1064.It Cd options NFS_BOOT_BOOTPARAM 1065Enable use of the BOOTPARAM protocol, consisting of RARP and 1066BOOTPARAM RPC, to get configuration information if NFS 1067is used to mount the root file system. 1068See 1069.Xr diskless 8 1070for details. 1071.It Cd options NFS_BOOT_RWSIZE=value 1072Set the initial NFS read and write sizes for diskless-boot requests. 1073The normal default is 8Kbytes. 1074This option provides a way to lower the value (e.g., to 1024 bytes) 1075as a workaround for buggy network interface cards or boot PROMs. 1076Once booted, the read and write request sizes can be increased by 1077remounting the file system. 1078See 1079.Xr mount_nfs 8 1080for details. 1081.It Cd options NFS_V2_ONLY 1082Reduce the size of the NFS client code by omitting code that's only required 1083for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1084servers. 1085.It Cd options SOFTDEP 1086Enable kernel support for soft-dependencies in FFS file systems. 1087Softdep improves write performance by aggregating and properly 1088ordering disk metadata writes, achieving near-asynchronous write 1089performance while maintaining the file system consistency of 1090synchronous writes. 1091Soft-dependencies are enabled on a per-mount basis. 1092See 1093.Xr mount 8 1094for details. 1095.It Cd options UFS_DIRHASH 1096Increase lookup performance by maintaining in-core hash tables 1097for large directories. 1098.El 1099.Ss Buffer queue strategy options 1100The following options enable alternative buffer queue strategies. 1101.Bl -ohang 1102.It Cd options BUFQ_READPRIO 1103Enable experimental buffer queue strategy for disk I/O. 1104In the default strategy, outstanding disk requests are ordered by 1105sector number and sent to the disk, regardless of whether the 1106operation is a read or write; this option gives priority to issuing 1107read requests over write requests. 1108Although requests may therefore be issued out of sector-order, causing 1109more seeks and thus lower overall throughput, interactive system 1110responsiveness under heavy disk I/O load may be improved, as processes 1111blocking on disk reads are serviced sooner (file writes typically 1112don't cause applications to block). 1113The performance effect varies greatly depending on the hardware, drive 1114firmware, file system configuration, workload, and desired performance 1115trade-off. 1116Systems using drive write-cache (most modern IDE disks, by default) 1117are unlikely to benefit and may well suffer; such disks acknowledge 1118writes very quickly, and optimize them internally according to 1119physical layout. 1120Giving these disks as many requests to work with as possible (the 1121standard strategy) will typically produce the best results, especially 1122if the drive has a large cache; the drive will silently complete 1123writes from cache as it seeks for reads. 1124Disks that support a large number of concurrent tagged requests (SCSI 1125disks and many hardware RAID controllers) expose this internal 1126scheduling with tagged responses, and don't block for reads; such 1127disks may not see a noticeable difference with either strategy. 1128However, if IDE disks are run with write-cache disabled for safety, 1129writes are not acknowledged until actually completed, and only one 1130request can be outstanding; a large number of small writes in one 1131locality can keep the disk busy, starving reads elsewhere on the disk. 1132Such systems are likely to see the most benefit from this option. 1133Finally, the performance interaction of this option with ffs soft 1134dependencies can be subtle, as that mechanism can drastically alter 1135the workload for file system metadata writes. 1136.It Cd options BUFQ_PRIOCSCAN 1137Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1138.It Cd options NEW_BUFQ_STRATEGY 1139Synonym of 1140.Em BUFQ_READPRIO . 1141.El 1142.Ss Miscellaneous Options 1143.Bl -ohang 1144.It Cd options MEMORY_DISK_DYNAMIC 1145This option makes the 1146.Xr md 4 1147.Tn RAM 1148disk size dynamically sized. 1149It is incompatible with 1150.Xr mdsetimage 8 . 1151.It Cd options MEMORY_DISK_HOOKS 1152This option allows for some machine dependent functions to be called when 1153the 1154.Xr md 4 1155.Tn RAM 1156disk driver is configured. 1157This can result in automatically loading a 1158.Tn RAM 1159disk from floppy on open (among other things). 1160.It Cd options MEMORY_DISK_IS_ROOT 1161Forces the 1162.Xr md 4 1163.Tn RAM 1164disk to be the root device. 1165This can only be overridden when 1166the kernel is booted in the 'ask-for-root' mode. 1167.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1168Allocates the given number of 512 byte blocks as memory for the 1169.Xr md 4 1170.Tn RAM 1171disk, to be populated with 1172.Xr mdsetimage 8 . 1173.It Cd options MEMORY_DISK_SERVER=0 1174Do not include the interface to a userland memory disk server process. 1175Per default, this option is set to 1, including the support code. 1176Useful for install media kernels. 1177.It Cd options MODULAR 1178Enables the framework for kernel modules. 1179.It Cd options VND_COMPRESSION 1180Enables the 1181.Xr vnd 4 1182driver to also handle compressed images. 1183See 1184.Xr vndcompress 1 , 1185.Xr vnd 4 1186and 1187.Xr vnconfig 8 1188for more information. 1189.It Cd options TFTPROOT 1190Download the root memory disk through TFTP at root mount time. 1191This enables the use of a root 1192.Tn RAM 1193disk without requiring it to be embedded in the kernel using 1194.Xr mdsetimage 8 . 1195The 1196.Tn RAM 1197disk name is obtained using DHCP's filename parameter. 1198This option requires 1199.Em MEMORY_DISK_HOOKS , 1200.Em MEMORY_DISK_DYNAMIC , 1201and 1202.Em MEMORY_DISK_IS_ROOT . 1203It is incompatible with 1204.Em MEMORY_DISK_ROOT_SIZE . 1205.It Cd options MALLOC_NOINLINE 1206Time critical fixed size memory allocation is performed with 1207.Fn MALLOC 1208and 1209.Fn FREE . 1210Normally these expand to inline code, but with 1211.Em MALLOC_NOINLINE 1212these call the normal 1213.Fn malloc 1214and 1215.Fn free 1216functions. 1217Useful for install media kernels, small memory systems and embedded systems. 1218.It Cd options HZ=integer 1219On ports that support it, set the system clock frequency (see 1220.Xr hz 9 ) 1221to the supplied value. 1222Handle with care. 1223.It Cd options NTP 1224Turns on in-kernel precision timekeeping support used by software 1225implementing 1226.Em NTP 1227(Network Time Protocol, RFC 1305). 1228The 1229.Em NTP 1230option adds an in-kernel Phase-Locked Loop (PLL) for normal 1231.Em NTP 1232operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1233operation. 1234.Xr ntpd 8 1235will employ a user-level PLL when kernel support is unavailable, 1236but the in-kernel version has lower latency and more precision, and 1237so typically keeps much better time. 1238The interface to the kernel 1239.Em NTP 1240support is provided by the 1241.Xr ntp_adjtime 2 1242and 1243.Xr ntp_gettime 2 1244system calls, which are intended for use by 1245.Xr ntpd 8 1246and are enabled by the option. 1247On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1248is not an integer, the 1249.Em NTP 1250option also enables extended-precision arithmetic to keep track of 1251fractional clock ticks at NTP time-format precision. 1252.It Cd options PPS_SYNC 1253This option enables a kernel serial line discipline for receiving time 1254phase signals from an external reference clock such as a radio clock. 1255(The 1256.Em NTP 1257option (which see) must be on if the 1258.Em PPS_SYNC 1259option is used.) 1260Some reference clocks generate a Pulse Per Second (PPS) signal in 1261phase with their time source. 1262The 1263.Em PPS 1264line discipline receives this signal on either the data leads 1265or the DCD control lead of a serial port. 1266.Em NTP 1267uses the PPS signal to discipline the local clock oscillator to a high 1268degree of precision (typically less than 50 microseconds in time and 12690.1 ppm in accuracy). 1270.Em PPS 1271can also generate a serial output pulse when the system receives a PPS 1272interrupt. 1273This can be used to measure the system interrupt latency and thus calibrate 1274.Em NTP 1275to account for it. 1276Using 1277.Em PPS 1278usually requires a 1279gadget box 1280to convert from TTL to RS-232 signal levels. 1281The gadget box and PPS are described in more detail in the HTML documentation 1282for 1283.Xr ntpd 8 1284in 1285.Pa /usr/share/doc/html/ntp . 1286.It Cd options SETUIDSCRIPTS 1287Allows scripts with the setuid bit set to execute as the effective 1288user rather than the real user, just like binary executables. 1289.Pp 1290.Em NOTE : 1291Using this option will also enable 1292.Em options FDSCRIPTS 1293.It Cd options FDSCRIPTS 1294Allows execution of scripts with the execute bit set, but not the 1295read bit, by opening the file and passing the file descriptor to 1296the shell, rather than the filename. 1297.Pp 1298.Em NOTE : 1299Execute only (non-readable) scripts will have 1300.Va argv[0] 1301set to 1302.Pa /dev/fd/* . 1303What this option allows as far as security is 1304concerned, is the ability to safely ensure that the correct script 1305is run by the interpreter, as it is passed as an already open file. 1306.It Cd options PUCCN 1307Enables treating serial ports found on PCI boards 1308.Xr puc 4 1309as potential console devices. 1310The method for choosing such a console device is port dependent. 1311.It Cd options RTC_OFFSET=integer 1312The kernel (and typically the hardware battery backed-up clock on 1313those machines that have one) keeps time in 1314.Em UTC 1315(Universal Coordinated Time, once known as 1316.Em GMT , 1317or Greenwich Mean Time) 1318and not in the time of the local time zone. 1319The 1320.Em RTC_OFFSET 1321option is used on some ports (such as the i386) to tell the kernel 1322that the hardware clock is offset from 1323.Em UTC 1324by the specified number of minutes. 1325This is typically used when a machine boots several operating 1326systems and one of them wants the hardware clock to run in the 1327local time zone and not in 1328.Em UTC , 1329e.g. 1330.Em RTC_OFFSET=300 1331means 1332the hardware clock is set to US Eastern Time (300 minutes behind 1333.Em UTC ) , 1334and not 1335.Em UTC . 1336(Note: 1337.Em RTC_OFFSET 1338is used to initialize a kernel variable named 1339.Va rtc_offset 1340which is the source actually used to determine the clock offset, and 1341which may be accessed via the kern.rtc_offset sysctl variable. 1342See 1343.Xr sysctl 8 1344and 1345.Xr sysctl 3 1346for details. 1347Since the kernel clock is initialized from the hardware clock very 1348early in the boot process, it is not possible to meaningfully change 1349.Va rtc_offset 1350in system initialization scripts. 1351Changing this value currently may only be done at kernel compile 1352time or by patching the kernel and rebooting). 1353.Pp 1354.Em NOTE : 1355Unfortunately, in many cases where the hardware clock 1356is kept in local time, it is adjusted for Daylight Savings 1357Time; this means that attempting to use 1358.Em RTC_OFFSET 1359to let 1360.Nx 1361coexist with such an operating system, like Windows, 1362would necessitate changing 1363.Em RTC_OFFSET 1364twice a year. 1365As such, this solution is imperfect. 1366.It Cd options KMEMSTATS 1367The kernel memory allocator, 1368.Xr malloc 9 , 1369will keep statistics on its performance if this option is enabled. 1370Unfortunately, this option therefore essentially disables the 1371.Fn MALLOC 1372and 1373.Fn FREE 1374forms of the memory allocator, which are used to enhance the performance 1375of certain critical sections of code in the kernel. 1376This option therefore can lead to a significant decrease in the 1377performance of certain code in the kernel if enabled. 1378Examples of such code include the 1379.Fn namei 1380routine, the 1381.Xr ccd 4 1382driver, 1383and much of the networking code. 1384.It Cd options MAXUPRC=integer 1385Sets the soft 1386.Dv RLIMIT_NPROC 1387resource limit, which specifies the maximum number of simultaneous 1388processes a user is permitted to run, for process 0; 1389this value is inherited by its child processes. 1390It defaults to 1391.Em CHILD_MAX , 1392which is currently defined to be 160. 1393Setting 1394.Em MAXUPRC 1395to a value less than 1396.Em CHILD_MAX 1397is not permitted, as this would result in a violation of the semantics of 1398.St -p1003.1-90 . 1399.It Cd options NOFILE=integer 1400Sets the soft 1401.Dv RLIMIT_NOFILE 1402resource limit, which specifies the maximum number of open 1403file descriptors for each process; 1404this value is inherited by its child processes. 1405It defaults to 1406.Em OPEN_MAX , 1407which is currently defined to be 64. 1408.It Cd options MAXFILES=integer 1409Sets the default value of the 1410.Em kern.maxfiles 1411sysctl variable, which indicates the maximum number of files that may 1412be open in the system. 1413.It Cd options DEFCORENAME=string 1414Sets the default value of the 1415.Em kern.defcorename 1416sysctl variable, otherwise it is set to 1417.Nm %n.core . 1418See 1419.Xr sysctl 8 1420and 1421.Xr sysctl 3 1422for details. 1423.It Cd options RASOPS_CLIPPING 1424Enables clipping within the 1425.Nm rasops 1426raster-console output system. 1427.Em NOTE : 1428only available on architectures that use 1429.Nm rasops 1430for console output. 1431.It Cd options RASOPS_SMALL 1432Removes optimized character writing code from the 1433.Nm rasops 1434raster-console output system. 1435.Em NOTE : 1436only available on architectures that use 1437.Nm rasops 1438for console output. 1439.It Cd options INCLUDE_CONFIG_FILE 1440Embeds the kernel config file used to define the kernel in the kernel 1441binary itself. 1442The embedded data also includes any files directly included by the config 1443file itself, e.g. 1444.Pa GENERIC.local 1445or 1446.Pa std.$MACHINE . 1447The embedded config file can be extracted from the resulting kernel with 1448.Xr config 1 1449.Fl x , 1450or by the following command: 1451.Bd -literal -offset indent 1452strings netbsd | sed -n 's/^_CFG_//p' | unvis 1453.Ed 1454.It Cd options INCLUDE_JUST_CONFIG 1455Similar to the above option, but includes just the actual config file, 1456not any included files. 1457.It Cd options PIPE_SOCKETPAIR 1458Use slower, but smaller socketpair(2)-based pipe implementation instead 1459of default faster, but bigger one. 1460Primarily useful for installation kernels. 1461.It Cd options USERCONF 1462Compiles in the in-kernel device configuration manager. 1463See 1464.Xr userconf 4 1465for details. 1466.It Cd options PERFCTRS 1467Compiles in kernel support for CPU performance-monitoring counters. 1468See 1469.Xr pmc 1 1470for details. 1471.Em NOTE : 1472not available on all architectures. 1473.It Cd options SYSCALL_STATS 1474Count the number of times each system call number is called. 1475The values can be read through the sysctl interface and displayed using 1476.Xr systat 1 . 1477.Em NOTE : 1478not yet available on all architectures. 1479.It Cd options SYSCALL_TIMES 1480Count the time spent (using 1481.Fn cpu_counter32 ) 1482in each system call. 1483.Em NOTE : 1484Using this option will also enable 1485.Cd options SYSCALL_STATS . 1486.It Cd options SYSCALL_TIMES_HASCOUNTER 1487Force use of 1488.Fn cpu_counter32 1489even if 1490.Fn cpu_hascounter 1491reports false. 1492Useful for systems where the cycle counter doesn't run at a constant rate 1493(e.g. Soekris boxes). 1494.It Cd options XSERVER 1495Compiles in kernel support for 1496.Tn X11 1497on architectures that still use (or can use) the legacy 1498.Em pccons 1499console drivers rather than 1500.Xr wscons 4 . 1501These include bebox, i386, shark. 1502.It Cd options XSERVER_DDB 1503A supplement to XSERVER that adds support for entering 1504.Xr ddb 4 1505while in 1506.Tn X11 . 1507.It Cd options FILEASSOC 1508Support for 1509.Xr fileassoc 9 . 1510.It Cd options FILEASSOC_NHOOKS=integer 1511Number of storage slots per file for 1512.Xr fileassoc 9 . 1513Default is 4. 1514.It Cd options I2C_SCAN 1515Scan each i2c bus to determine which addresses respond. 1516.Pp 1517.Em WARNING ! 1518Using this option can access some devices in such a 1519manner as to leave them in an unstable or unuseable state, and 1520can prevent those devices from being properly matched and/or 1521attached. 1522It can also lock up the entire i2c bus and even 1523prevent a machine from completing the boot process. 1524Don't use this option unless you know what you're doing and can 1525accept all sorts of unforseen consequences. 1526.El 1527.Ss Networking Options 1528.Bl -ohang 1529.It Cd options GATEWAY 1530Enables 1531.Em IPFORWARDING 1532(which see) 1533and (on most ports) increases the size of 1534.Em NMBCLUSTERS 1535(which see). 1536In general, 1537.Em GATEWAY 1538is used to indicate that a system should act as a router, and 1539.Em IPFORWARDING 1540is not invoked directly. 1541(Note that 1542.Em GATEWAY 1543has no impact on protocols other than 1544.Tn IP , 1545such as 1546.Tn CLNP 1547or 1548.Tn XNS ) . 1549.Em GATEWAY 1550option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1551.It Cd options ICMPPRINTFS 1552The 1553.Em ICMPPRINTFS 1554option will enable debugging information to be printed about 1555the 1556.Xr icmp 4 1557protocol. 1558.It Cd options IPFORWARDING=value 1559If 1560.Em value 1561is 1 this enables IP routing behavior. 1562If 1563.Em value 1564is 0 (the default), it disables it. 1565The 1566.Em GATEWAY 1567option sets this to 1 automatically. 1568With this option enabled, the machine will forward IP datagrams destined 1569for other machines between its interfaces. 1570Note that even without this option, the kernel will 1571still forward some packets (such as source routed packets) -- removing 1572.Em GATEWAY 1573and 1574.Em IPFORWARDING 1575is insufficient to stop all routing through a bastion host on a 1576firewall -- source routing is controlled independently. 1577To turn off source routing, use 1578.Em options IPFORWSRCRT=0 1579(which see). 1580Note that IP forwarding may be turned on and off independently of the 1581setting of the 1582.Em IPFORWARDING 1583option through the use of the 1584.Em net.inet.ip.forwarding 1585sysctl variable. 1586If 1587.Em net.inet.ip.forwarding 1588is 1, IP forwarding is on. 1589See 1590.Xr sysctl 8 1591and 1592.Xr sysctl 3 1593for details. 1594.It Cd options IPFORWSRCRT=value 1595If 1596.Em value 1597is set to zero, source routing of IP datagrams is turned off. 1598If 1599.Em value 1600is set to one (the default) or the option is absent, source routed IP 1601datagrams are forwarded by the machine. 1602Note that source routing of IP packets may be turned on and off 1603independently of the setting of the 1604.Em IPFORWSRCRT 1605option through the use of the 1606.Em net.inet.ip.forwsrcrt 1607sysctl variable. 1608If 1609.Em net.inet.ip.forwsrcrt 1610is 1, forwarding of source routed IP datagrams is on. 1611See 1612.Xr sysctl 8 1613and 1614.Xr sysctl 3 1615for details. 1616.It Cd options IFA_STATS 1617Tells the kernel to maintain per-address statistics on bytes sent 1618and received over (currently) Internet and AppleTalk addresses. 1619.\"This can be a fairly expensive operation, so you probably want to 1620.\"keep this disabled. 1621The option is not recommended as it degrades system stability. 1622.It Cd options IFQ_MAXLEN=value 1623Increases the allowed size of the network interface packet queues. 1624The default queue size is 50 packets, and you do not normally need 1625to increase it. 1626.It Cd options IPSELSRC 1627Includes support for source-address selection policies. 1628See 1629.Xr in_getifa 9 . 1630.It Cd options MROUTING 1631Includes support for IP multicast routers. 1632You certainly want 1633.Em INET 1634with this. 1635Multicast routing is controlled by the 1636.Xr mrouted 8 1637daemon. 1638See also option 1639.Cd PIM . 1640.It Cd options PIM 1641Includes support for Protocol Independent Multicast (PIM) routing. 1642You need 1643.Em MROUTING 1644and 1645.Em INET 1646with this. 1647Software using this can be found e.g. in 1648.Pa pkgsrc/net/xorp . 1649.It Cd options INET 1650Includes support for the 1651.Tn TCP/IP 1652protocol stack. 1653You almost certainly want this. 1654See 1655.Xr inet 4 1656for details. 1657.It Cd options INET6 1658Includes support for the 1659.Tn IPv6 1660protocol stack. 1661See 1662.Xr inet6 4 1663for details. 1664Unlike 1665.Em INET , 1666.Em INET6 1667enables multicast routing code as well. 1668This option requires 1669.Em INET 1670at this moment, but it should not. 1671.It Cd options ND6_DEBUG 1672The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1673for debugging IPv6 neighbor discovery protocol handling. 1674See 1675.Xr sysctl 3 1676for details. 1677.It Cd options IPSEC 1678Includes support for the 1679.Tn IPsec 1680protocol. 1681See 1682.Xr ipsec 4 1683for details. 1684.It Cd options IPSEC_DEBUG 1685Enables debugging code in 1686.Tn IPsec 1687stack. 1688See 1689.Xr ipsec 4 1690for details. 1691.It Cd options IPSEC_ESP 1692Includes support for 1693.Tn IPsec 1694.Tn ESP 1695protocol. 1696See 1697.Xr ipsec 4 1698for details. 1699.It Cd options IPSEC_NAT_T 1700Includes support for 1701.Tn IPsec 1702Network Address Translator traversal (NAT-T), as described in RFCs 3947 1703and 3948. 1704This feature might be patent-encumbered in some countries. 1705.It Cd options ALTQ 1706Enabled ALTQ (Alternate Queueing). 1707For simple rate-limiting, use 1708.Xr tbrconfig 8 1709to set up the interface transmission rate. 1710To use queueing disciplines, their appropriate kernel options should also 1711be defined (documented below). 1712Queueing disciplines are managed by 1713.Xr altqd 8 . 1714See 1715.Xr altq 9 1716for details. 1717.It Cd options ALTQ_HFSC 1718Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1719module. 1720HFSC supports both link-sharing and guaranteed real-time services. 1721HFSC employs a service curve based QoS model, and its unique feature 1722is an ability to decouple delay and bandwidth allocation. 1723Requires 1724.Em ALTQ_RED 1725to use the RED queueing discipline on HFSC classes, or 1726.Em ALTQ_RIO 1727to use the RIO queueing discipline on HFSC classes. 1728This option assumes 1729.Em ALTQ . 1730.It Cd options ALTQ_PRIQ 1731Include support for ALTQ-implemented PRIQ (Priority Queueing). 1732PRIQ implements a simple priority-based queueing discipline. 1733A higher priority class is always served first. 1734Requires 1735.Em ALTQ_RED 1736to use the RED queueing discipline on HFSC classes, or 1737.Em ALTQ_RIO 1738to use the RIO queueing discipline on HFSC classes. 1739This option assumes 1740.Em ALTQ . 1741.It Cd options ALTQ_WFQ 1742Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1743WFQ implements a weighted-round robin scheduler for a set of queues. 1744A weight can be assigned to each queue to give a different proportion 1745of the link capacity. 1746A hash function is used to map a flow to one of a set of queues. 1747This option assumes 1748.Em ALTQ . 1749.It Cd options ALTQ_FIFOQ 1750Include support for ALTQ-implemented FIFO queueing. 1751FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1752This option assumes 1753.Em ALTQ . 1754.It Cd options ALTQ_RIO 1755Include support for ALTQ-implemented RIO (RED with In/Out). 1756The original RIO has 2 sets of RED parameters; one for in-profile 1757packets and the other for out-of-profile packets. 1758At the ingress of the network, profile meters tag packets as IN or 1759OUT based on contracted profiles for customers. 1760Inside the network, IN packets receive preferential treatment by 1761the RIO dropper. 1762ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1763PHB of DiffServ (RFC 2597). 1764This option assumes 1765.Em ALTQ . 1766.It Cd options ALTQ_BLUE 1767Include support for ALTQ-implemented Blue buffer management. 1768Blue is another active buffer management mechanism. 1769This option assumes 1770.Em ALTQ . 1771.It Cd options ALTQ_FLOWVALVE 1772Include support for ALTQ-implemented Flowvalve. 1773Flowvalve is a simple implementation of a RED penalty box that identifies 1774and punishes misbehaving flows. 1775This option requires 1776.Em ALTQ_RED 1777and assumes 1778.Em ALTQ . 1779.It Cd options ALTQ_CDNR 1780Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1781packet marking/manipulation. 1782Traffic conditioners are components to meter, mark, or drop incoming 1783packets according to some rules. 1784As opposed to queueing disciplines, traffic conditioners handle incoming 1785packets at an input interface. 1786This option assumes 1787.Em ALTQ . 1788.It Cd options ALTQ_NOPCC 1789Disables use of processor cycle counter to measure time in ALTQ. 1790This option should be defined for a non-Pentium i386 CPU which does not 1791have TSC, SMP (per-CPU counters are not in sync), or power management 1792which affects processor cycle counter. 1793This option assumes 1794.Em ALTQ . 1795.It Cd options ALTQ_IPSEC 1796Include support for IPsec in IPv4 ALTQ. 1797This option assumes 1798.Em ALTQ . 1799.It Cd options ALTQ_JOBS 1800Include support for ALTQ-implemented JoBS (Joint Buffer Management 1801and Scheduling). 1802This option assumes 1803.Em ALTQ . 1804.It Cd options ALTQ_AFMAP 1805Include support for an undocumented ALTQ feature that is used to map an IP 1806flow to an ATM VC (Virtual Circuit). 1807This option assumes 1808.Em ALTQ . 1809.It Cd options ALTQ_LOCALQ 1810Include support for ALTQ-implemented local queues. 1811Its practical use is undefined. 1812Assumes 1813.Em ALTQ . 1814.It Cd options SUBNETSARELOCAL 1815Sets default value for net.inet.ip.subnetsarelocal variable, which 1816controls whether non-directly-connected subnets of connected networks 1817are considered "local" for purposes of choosing the MSS for a TCP 1818connection. 1819This is mostly present for historic reasons and completely irrelevant if 1820you enable Path MTU discovery. 1821.It Cd options HOSTZEROBROADCAST 1822Sets default value for net.inet.ip.hostzerobroadcast variable, which 1823controls whether the zeroth host address of each connected subnet is 1824also considered a broadcast address. 1825Default value is "1", for compatibility with old systems; if this is 1826set to zero on all hosts on a subnet, you should be able to fit an extra 1827host per subnet on the 1828".0" address. 1829.It Cd options MCLSHIFT=value 1830This option is the base-2 logarithm of the size of mbuf clusters. 1831The 1832.Bx 1833networking stack keeps network packets in a linked 1834list, or chain, of kernel buffer objects called mbufs. 1835The system provides larger mbuf clusters as an optimization for 1836large packets, instead of using long chains for large packets. 1837The mbuf cluster size, 1838or 1839.Em MCLBYTES , 1840must be a power of two, and is computed as two raised to the power 1841.Em MCLSHIFT . 1842On systems with Ethernet network adapters, 1843.Em MCLSHIFT 1844is often set to 11, giving 2048-byte mbuf clusters, large enough to 1845hold a 1500-byte 1846.Tn Ethernet 1847frame in a single cluster. 1848Systems with network interfaces supporting larger frame sizes like 1849.Tn ATM , 1850.Tn FDDI , 1851or 1852.Tn HIPPI 1853may perform better with 1854.Em MCLSHIFT 1855set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1856respectively. 1857.It Cd options NS 1858Include support for the 1859.Tn Xerox 1860.Tn XNS 1861protocol stack. 1862See 1863.Xr ns 4 1864for details. 1865.It Cd options ISO,TPIP 1866Include support for the ubiquitous 1867.Tn OSI 1868protocol stack. 1869See 1870.Xr iso 4 1871for details. 1872This option assumes 1873.Em INET . 1874.It Cd options EON 1875Include support for tunneling 1876.Tn OSI 1877protocols over 1878.Tn IP . 1879Known to be broken, or at least very fragile, and undocumented. 1880.It Cd options NETATALK 1881Include support for the 1882.Tn AppleTalk 1883protocol stack. 1884The kernel provides provision for the 1885.Em Datagram Delivery Protocol 1886(DDP), providing SOCK_DGRAM support and 1887.Tn AppleTalk 1888routing. 1889This stack is used by the 1890.Em NETATALK 1891package, which adds support for 1892.Tn AppleTalk 1893server services via user libraries and applications. 1894.It Cd options BLUETOOTH 1895Include support for the 1896.Tn Bluetooth 1897protocol stack. 1898See 1899.Xr bluetooth 4 1900for details. 1901.It Cd options IPNOPRIVPORTS 1902Normally, only root can bind a socket descriptor to a so-called 1903.Dq privileged 1904.Tn TCP 1905port, that is, a port number in the range 0-1023. 1906This option eliminates those checks from the kernel. 1907This can be useful if there is a desire to allow daemons without 1908privileges to bind those ports, e.g., on firewalls. 1909The security tradeoffs in doing this are subtle. 1910This option should only be used by experts. 1911.It Cd options TCP_COMPAT_42 1912.Tn TCP 1913bug compatibility with 1914.Bx 4.2 . 1915In 1916.Bx 4.2 , 1917.Tn TCP 1918sequence numbers were 32-bit signed values. 1919Modern implementations of TCP use unsigned values. 1920This option clamps the initial sequence number to start in 1921the range 2^31 rather than the full unsigned range of 2^32. 1922Also, under 1923.Bx 4.2 , 1924keepalive packets must contain at least one byte or else 1925the remote end would not respond. 1926.It Cd options TCP_DEBUG 1927Record the last 1928.Em TCP_NDEBUG 1929TCP packets with SO_DEBUG set, and decode to the console if 1930.Em tcpconsdebug 1931is set. 1932.It Cd options TCP_NDEBUG 1933Number of packets to record for 1934.Em TCP_DEBUG . 1935Defaults to 100. 1936.It Cd options TCP_SENDSPACE=value 1937.It Cd options TCP_RECVSPACE=value 1938These options set the max TCP window size to other sizes than the default. 1939The TCP window sizes can be altered via 1940.Xr sysctl 8 1941as well. 1942.It Cd options TCP_INIT_WIN=value 1943This option sets the initial TCP window size for non-local connections, 1944which is used when the transmission starts. 1945The default size is 1, but if the machine should act more aggressively, 1946the initial size can be set to some other value. 1947The initial TCP window size can be set via 1948.Xr sysctl 8 1949as well. 1950.It Cd options PFIL_HOOKS 1951This option turns on the packet filter interface hooks. 1952See 1953.Xr pfil 9 1954for details. 1955This option assumes 1956.Em INET . 1957.It Cd options IPFILTER_LOG 1958This option, in conjunction with 1959.Em pseudo-device ipfilter , 1960enables logging of IP packets using ip-filter. 1961.It Cd options IPFILTER_DEFAULT_BLOCK 1962This option sets the default policy of ip-filter. 1963If it is set, ip-filter will block packets by default. 1964.It Cd options BRIDGE_IPF 1965This option causes 1966.Em bridge 1967devices to use the IP and/or IPv6 filtering hooks, forming 1968a link-layer filter that uses protocol-layer rules. 1969This option assumes the presence of 1970.Em pseudo-device ipfilter . 1971.It Cd options MBUFTRACE 1972This option can help track down mbuf leaks. 1973When enabled, mbufs are tagged with the devices and protocols using them, 1974which slightly decreases network performance. 1975This additional information can be viewed with 1976.Xr netstat 1 : 1977.Dl Ic netstat Fl mssv 1978Not all devices or protocols support this option. 1979.El 1980.Ss Sysctl Related Options 1981.Bl -ohang 1982.It Cd options SYSCTL_DISALLOW_CREATE 1983Disallows the creation or deletion of nodes from the sysctl tree, as 1984well as the assigning of descriptions to nodes that lack them, by any 1985process. 1986These operations are still available to kernel sub-systems, including 1987loadable kernel modules. 1988.It Cd options SYSCTL_DISALLOW_KWRITE 1989Prevents processes from adding nodes to the sysctl tree that make 1990existing kernel memory areas writable. 1991Sections of kernel memory can still be read and new nodes that own 1992their own data may still be writable. 1993.It Cd options SYSCTL_DEBUG_SETUP 1994Causes the SYSCTL_SETUP routines to print a brief message when they 1995are invoked. 1996This is merely meant as an aid in determining the order in which 1997sections of the tree are created. 1998.It Cd options SYSCTL_DEBUG_CREATE 1999Prints a message each time 2000.Fn sysctl_create , 2001the function that adds nodes to the tree, is called. 2002.It Cd options SYSCTL_INCLUDE_DESCR 2003Causes the kernel to include short, human readable descriptions for 2004nodes in the sysctl tree. 2005The descriptions can be retrieved programmatically (see 2006.Xr sysctl 3 ) , 2007or by the sysctl binary itself (see 2008.Xr sysctl 8 ) . 2009The descriptions are meant to give an indication of the purpose and/or 2010effects of a given node's value, not replace the documentation for the 2011given subsystem as a whole. 2012.El 2013.Ss System V IPC Options 2014.Bl -ohang 2015.It Cd options SYSVMSG 2016Includes support for 2017.At V 2018style message queues. 2019See 2020.Xr msgctl 2 , 2021.Xr msgget 2 , 2022.Xr msgrcv 2 , 2023.Xr msgsnd 2 . 2024.It Cd options SYSVSEM 2025Includes support for 2026.At V 2027style semaphores. 2028See 2029.Xr semctl 2 , 2030.Xr semget 2 , 2031.Xr semop 2 . 2032.It Cd options SEMMNI=value 2033Sets the number of 2034.At V 2035style semaphore identifiers. 2036The GENERIC config file for your port will have the default. 2037.It Cd options SEMMNS=value 2038Sets the number of 2039.At V 2040style semaphores in the system. 2041The GENERIC config file for your port will have the default. 2042.It Cd options SEMUME=value 2043Sets the maximum number of undo entries per process for 2044.At V 2045style semaphores. 2046The GENERIC config file for your port will have the default. 2047.It Cd options SEMMNU=value 2048Sets the number of undo structures in the system for 2049.At V 2050style semaphores. 2051The GENERIC config file for your port will have the default. 2052.It Cd options SYSVSHM 2053Includes support for 2054.At V 2055style shared memory. 2056See 2057.Xr shmat 2 , 2058.Xr shmctl 2 , 2059.Xr shmdt 2 , 2060.Xr shmget 2 . 2061.It Cd options SHMMAXPGS=value 2062Sets the maximum number of 2063.At V 2064style shared memory pages that are available through the 2065.Xr shmget 2 2066system call. 2067Default value is 1024 on most ports. 2068See 2069.Pa /usr/include/machine/vmparam.h 2070for the default. 2071.El 2072.Ss VM Related Options 2073.Bl -ohang 2074.It Cd options NMBCLUSTERS=value 2075The number of mbuf clusters the kernel supports. 2076Mbuf clusters are MCLBYTES in size (usually 2k). 2077This is used to compute the size of the kernel VM map 2078.Em mb_map , 2079which maps mbuf clusters. 2080Default on most ports is 1024 (2048 with 2081.Dq options GATEWAY 2082). 2083See 2084.Pa /usr/include/machine/param.h 2085for exact default information. 2086Increase this value if you get 2087.Dq mclpool limit reached 2088messages. 2089.It Cd options NKMEMPAGES=value 2090.It Cd options NKMEMPAGES_MIN=value 2091.It Cd options NKMEMPAGES_MAX=value 2092Size of kernel VM map 2093.Em kmem_map , 2094in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2095from the 2096.Xr sysctl 8 2097variable 2098.Em hw.pagesize 2099). 2100This VM map is used to map the kernel malloc arena. 2101The kernel attempts to auto-size this map based on the amount of 2102physical memory in the system. 2103Platform-specific code may place bounds on this computed size, 2104which may be viewed with the 2105.Xr sysctl 8 2106variable 2107.Em vm.nkmempages . 2108See 2109.Pa /usr/include/machine/param.h 2110for the default upper and lower bounds. 2111The related options 2112.Sq NKMEMPAGES_MIN 2113and 2114.Sq NKMEMPAGES_MAX 2115allow the bounds to be overridden in the kernel configuration file. 2116These options are provided in the event the computed value is 2117insufficient resulting in an 2118.Dq out of space in kmem_map 2119panic. 2120.It Cd options SB_MAX=value 2121Sets the max size in bytes that a socket buffer is allowed to occupy. 2122The default is 256k, but sometimes it needs to be increased, for example 2123when using large TCP windows. 2124This option can be changed via 2125.Xr sysctl 8 2126as well. 2127.It Cd options SOMAXKVA=value 2128Sets the maximum size of kernel virtual memory that the socket buffers 2129are allowed to use. 2130The default is 16MB, but in situations where for example large TCP 2131windows are used this value must also be increased. 2132This option can be changed via 2133.Xr sysctl 8 2134as well. 2135.It Cd options BUFCACHE=value 2136Size of the buffer cache as a percentage of total available 2137.Tn RAM . 2138Ignored if BUFPAGES is also specified. 2139.It Cd options NBUF=value 2140Sets the number of buffer headers available, i.e., the number of 2141open files that may have a buffer cache entry. 2142Each buffer header 2143requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2144The default value is machine dependent, but is usually equal to the 2145value of BUFPAGES. 2146If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2147then NBUF may be reduced at run time so that the storage allocated 2148for buffer headers doesn't exceed that limit. 2149.It Cd options BUFPAGES=value 2150These options set the number of pages available for the buffer cache. 2151Their default value is a machine dependent value, often calculated as 2152between 5% and 10% of total available 2153.Tn RAM . 2154.It Cd options MAXTSIZ=bytes 2155Sets the maximum size limit of a process' text segment. 2156See 2157.Pa /usr/include/machine/vmparam.h 2158for the port-specific default. 2159.It Cd options DFLDSIZ=bytes 2160Sets the default size limit of a process' data segment, the value that 2161will be returned as the soft limit for 2162.Dv RLIMIT_DATA 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 MAXDSIZ=bytes 2169Sets the maximum size limit of a process' data segment, the value that 2170will be returned as the hard limit for 2171.Dv RLIMIT_DATA 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 DFLSSIZ=bytes 2178Sets the default size limit of a process' stack segment, the value that 2179will be returned as the soft limit for 2180.Dv RLIMIT_STACK 2181(as returned by 2182.Xr getrlimit 2 ) . 2183See 2184.Pa /usr/include/machine/vmparam.h 2185for the port-specific default. 2186.It Cd options MAXSSIZ=bytes 2187Sets the maximum size limit of a process' stack segment, the value that 2188will be returned as the hard limit for 2189.Dv RLIMIT_STACK 2190(as returned by 2191.Xr getrlimit 2 ) . 2192See 2193.Pa /usr/include/machine/vmparam.h 2194for the port-specific default. 2195.It Cd options DUMP_ON_PANIC=integer 2196Defaults to one. 2197If set to zero, the kernel will not dump to the dump device when 2198it panics, though dumps can still be forced via 2199.Xr ddb 4 2200with the 2201.Dq sync 2202command. 2203Note that this sets the value of the 2204.Em kern.dump_on_panic 2205.Xr sysctl 3 2206variable which may be changed at run time -- see 2207.Xr sysctl 8 2208for details. 2209.It Cd options USE_TOPDOWN_VM 2210User space memory allocations (as made by 2211.Xr mmap 2 ) 2212will be arranged in a 2213.Dq top down 2214fashion instead of the traditional 2215.Dq upwards from MAXDSIZ \+ vm_daddr 2216method. 2217This includes the placement of 2218.Xr ld.so 1 . 2219Arranging memory in this manner allows either (or both of) the heap or 2220.Xr mmap 2 2221allocated space to grow larger than traditionally possible. 2222This option is not available on all ports, but is instead expected to be 2223offered on a port-by-port basis, after which some ports will commit to 2224using it by default. 2225See the files 2226.Pa /usr/include/uvm/uvm_param.h 2227for some implementation details, and 2228.Pa /usr/include/machine/vmparam.h 2229for port specific details including availability. 2230.It Cd options VMSWAP 2231Enable paging device/file support. 2232This option is on by default. 2233.It Cd options PDPOLICY_CLOCKPRO 2234Use CLOCK-Pro, an alternative page replace policy. 2235.El 2236.Ss Security Options 2237.Bl -ohang 2238.It Cd options INSECURE 2239Hardwires the kernel security level at \-1. 2240This means that the system 2241always runs in secure level \-1 mode, even when running multiuser. 2242See the manual page for 2243.Xr init 8 2244for details on the implications of this. 2245The kernel secure level may manipulated by the superuser by altering the 2246.Em kern.securelevel 2247.Xr sysctl 3 2248variable (the secure level may only be lowered by a call from process ID 1, 2249i.e., 2250.Xr init 8 ) . 2251See also 2252.Xr secmodel_securelevel 9 , 2253.Xr sysctl 8 2254and 2255.Xr sysctl 3 . 2256.It Cd options VERIFIED_EXEC_FP_MD5 2257Enables support for MD5 hashes in Veriexec. 2258.It Cd options VERIFIED_EXEC_FP_SHA1 2259Enables support for SHA1 hashes in Veriexec. 2260.It Cd options VERIFIED_EXEC_FP_RMD160 2261Enables support for RMD160 hashes in Veriexec. 2262.It Cd options VERIFIED_EXEC_FP_SHA256 2263Enables support for SHA256 hashes in Veriexec. 2264.It Cd options VERIFIED_EXEC_FP_SHA384 2265Enables support for SHA384 hashes in Veriexec. 2266.It Cd options VERIFIED_EXEC_FP_SHA512 2267Enables support for SHA512 hashes in Veriexec. 2268.It Cd options PAX_MPROTECT=value 2269Enables PaX MPROTECT, 2270.Xr mprotect 2 2271restrictions from the PaX project. 2272.Pp 2273The 2274.Ar value 2275is the default value for the 2276.Em global 2277knob, see 2278.Xr sysctl 3 . 2279If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2280using 2281.Xr paxctl 8 . 2282If 1, PaX MPROTECT will be enabled for all programs. 2283Programs can be exempted using 2284.Xr paxctl 8 . 2285.Pp 2286See 2287.Xr security 8 2288for more details. 2289.It Cd options PAX_SEGVGUARD=value 2290Enables PaX Segvguard. 2291.Pp 2292The 2293.Ar value 2294is the default value for the 2295.Em global 2296knob, see 2297.Xr sysctl 3 . 2298If 0, PaX Segvguard will be enabled only if explicitly set on programs 2299using 2300.Xr paxctl 8 . 2301If 1, PaX Segvguard will be enabled to all programs, and exemption can 2302be done using 2303.Xr paxctl 8 . 2304.Pp 2305See 2306.Xr security 8 2307for more details. 2308.It Cd options PAX_ASLR=value 2309Enables PaX ASLR. 2310.Pp 2311The 2312.Ar value 2313is the default value for the 2314.Em global 2315knob, see 2316.Xr sysctl 3 . 2317If 0, PaX ASLR will be enabled only if explicitly set on programs 2318using 2319.Xr paxctl 8 . 2320If 1, PaX ASLR will be enabled to all programs, and exemption can 2321be done using 2322.Xr paxctl 8 . 2323.Pp 2324See 2325.Xr security 8 2326for more details. 2327.El 2328.Ss amiga-specific Options 2329.Bl -ohang 2330.It Cd options BB060STUPIDROM 2331When the bootloader (which passes 2332.Tn AmigaOS 2333.Tn ROM 2334information) claims we have a 68060 2335.Tn CPU 2336without 2337.Tn FPU , 2338go look into the Processor Configuration Register (PCR) to find out. 2339You need this with 2340.Tn Amiga 2341.Tn ROM Ns s 2342up to (at least) V40.xxx (OS3.1), 2343when you boot via the bootblocks and don't have a DraCo. 2344.It Cd options IOBZCLOCK=frequency 2345The IOBlix boards come with two different serial master clocks: older ones 2346use 24 MHz, newer ones use 22.1184 MHz. 2347The driver normally assumes the latter. 2348If your board uses 24 MHz, you can recompile your kernel with 2349options IOBZCLOCK=24000000 2350or patch the kernel variable 2351.Tn iobzclock 2352to the same value. 2353.It Cd options LIMITMEM=value 2354If there, limit the part of the first memory bank used by 2355.Nx 2356to value megabytes. 2357Default is unlimited. 2358.It Cd options NKPTADD=addvalue 2359.It Cd options NKPTADDSHIFT=shiftvalue 2360The 2361.Tn CPU 2362specific 2363.Tn MMU 2364table for the kernel is pre-allocated at kernel startup time. 2365Part of it is scaled with 2366.Va maxproc , 2367to have enough room to hold the user program 2368.Tn MMU 2369tables; the second part is a fixed amount for the kernel itself. 2370.Pp 2371The third part accounts for the size of the file buffer cache. 2372Its size is either 2373.Dv NKPTADD 2374pages (if defined) or memory size in bytes divided by two to 2375the power of 2376.Dv NKPTADDSHIFT . 2377The default is undefined 2378.Dv NKPTADD 2379and 2380.Dv NKPTADDSHIFT=24 , 2381allowing for 16 buffers per megabyte of main memory (while 2382a GENERIC kernel allocates about half of that). 2383When you get "can't get KPT page" panics, you should increase 2384.Dv NKPTADD 2385(if defined), or decrease 2386.Dv NKPTADDSHIFT 2387by one. 2388.It Cd options P5PPC68KBOARD 2389Add special support for Phase5 mixed 68k+PPC boards. 2390Currently, this only affects rebooting from 2391.Nx 2392and is only needed on 68040+PPC, not on 239368060+PPC; without this, affected machines will hang after 2394.Nx 2395has shut 2396down and will only restart after a keyboard reset or a power cycle. 2397.El 2398.Ss arm32-specific Options 2399.Bl -ohang 2400.It Cd options FRENCH_KBD 2401Include translation for French keyboards when using 2402.Em pccons 2403on a Shark. 2404.It Cd options FINNISH_KBD 2405Include translation for Finnish keyboards when using 2406.Em pccons 2407on a Shark. 2408.It Cd options GERMAN_KBD 2409Include translation for German keyboards when using 2410.Em pccons 2411on a Shark. 2412.It Cd options NORWEGIAN_KBD 2413Include translation for French keyboards when using 2414.Em pccons 2415on a Shark. 2416.El 2417.Ss amd64-specific Options 2418.Bl -ohang 2419.It Cd options ENHANCED_SPEEDSTEP 2420Include support for the 2421.Tn Enhanced SpeedStep Technology 2422present in newer 2423.Tn CPU Ns s . 2424.It Cd options EST_FREQ_USERWRITE 2425Allow any user to change the frequency of an 2426.Tn Enhanced SpeedStep Technology 2427capable 2428.Tn CPU . 2429.It Cd options INTEL_ONDEMAND_CLOCKMOD 2430This enables the On Demand Clock Modulation by software 2431on Intel 2432.Tn CPUs 2433supporting the Thermal Monitor feature (TM). 2434You can select the duty cycle with 2435.Xr sysctl 8 2436in the node 2437.Em machdep.clockmod 2438if supported. 2439.It Cd options POWERNOW_K8 2440Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2441Technology, used to change the cpu voltage and frequency 2442on the fly. 2443.El 2444.Ss atari-specific Options 2445.Bl -ohang 2446.It Cd options DISKLABEL_AHDI 2447Include support for AHDI (native Atari) disklabels. 2448.It Cd options DISKLABEL_NBDA 2449Include support for 2450.Nx Ns Tn /atari 2451labels. 2452If you don't set this option, it will be set automatically. 2453.Nx Ns Tn /atari 2454will not work without it. 2455.It Cd options FALCON_SCSI 2456Include support for the 5380-SCSI configuration as found on the Falcon. 2457.It Cd options RELOC_KERNEL 2458If set, the kernel will relocate itself to TT-RAM, if possible. 2459This will give you a slightly faster system. 2460.Em Beware 2461that on some TT030 systems, 2462the system will frequently dump with MMU-faults with this option enabled. 2463.It Cd options SERCONSOLE 2464Allow the modem1-port to act as the system-console. 2465A carrier should be active on modem1 during system boot to active 2466the console functionality. 2467.It Cd options TT_SCSI 2468Include support for the 5380-SCSI configuration as found on the TT030 2469and Hades. 2470.El 2471.Ss i386-specific Options 2472.Bl -ohang 2473.It Cd options ENHANCED_SPEEDSTEP 2474Include support for the 2475.Tn Enhanced SpeedStep Technology 2476present in newer 2477.Tn CPU Ns s . 2478.It Cd options EST_FREQ_USERWRITE 2479Allow any user to change the frequency of an 2480.Tn Enhanced SpeedStep Technology 2481capable 2482.Tn CPU . 2483.It Cd options INTEL_ONDEMAND_CLOCKMOD 2484This enables the On Demand Clock Modulation by software 2485on Intel 2486.Tn CPUs 2487supporting the Thermal Monitor feature (TM). 2488You can select the duty cycle with 2489.Xr sysctl 8 2490in the node 2491.Em machdep.clockmod 2492if supported. 2493.It Cd options POWERNOW_K7 2494Include support for the AMD 2495.Tn PowerNow! Technology 2496present in AMD Athlon Mobile processors. 2497.It Cd options VIA_PADLOCK 2498Include support for the 2499.Tn AES 2500encryption instructions of the 2501.Tn VIA PadLock Security engine , 2502which is attached as a provider to the opencrypto framework. 2503.It Cd options CPURESET_DELAY=value 2504Specifies the time (in millisecond) to wait before doing a hardware reset 2505in the last phase of a reboot. 2506This gives the user a chance to see error messages from the shutdown 2507operations (like NFS unmounts, buffer cache flush, etc ...). 2508Setting this to 0 will disable the delay. 2509Default is 2 seconds. 2510.It Cd options VM86 2511Include support for virtual 8086 mode, used by 2512.Tn DOS 2513emulators and X servers to run BIOS code, e.g., for some VESA routines. 2514.It Cd options USER_LDT 2515Include i386-specific system calls for modifying the local descriptor table, 2516used by Windows emulators. 2517.It Cd options REALBASEMEM=integer 2518Overrides the base memory size passed in from the boot block. 2519(Value given in kilobytes.) 2520Use this option only if the boot block reports the size incorrectly. 2521(Note that some 2522.Tn BIOS Ns es 2523put the extended 2524.Tn BIOS 2525data area at the top of base memory, and therefore report a smaller 2526base memory size to prevent programs overwriting it. 2527This is correct behavior, and you should not use the 2528.Em REALBASEMEM 2529option to access this memory). 2530.It Cd options REALEXTMEM=integer 2531Overrides the extended memory size passed in from the boot block. 2532(Value given in kilobytes. 2533Extended memory does not include the first megabyte.) 2534Use this option only if the boot block reports the size incorrectly. 2535.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2536Select a non-US keyboard layout for the 2537.Em pccons 2538console driver. 2539.It Cd options CYRIX_CACHE_WORKS 2540Relevant only to the Cyrix 486DLC CPU. 2541This option is used to turn on the cache in hold-flush mode. 2542It is not turned on by default because it is known to have problems in 2543certain motherboard implementations. 2544.It Cd options CYRIX_CACHE_REALLY_WORKS 2545Relevant only to the Cyrix 486DLC CPU. 2546This option is used to turn on the cache in write-back mode. 2547It is not turned on by default because it is known to have problems in 2548certain motherboard implementations. 2549In order for this option to take effect, option 2550.Em CYRIX_CACHE_WORKS 2551must also be specified. 2552.It Cd options PCIBIOS 2553Enable support for initializing the 2554.Tn PCI 2555bus using information from the 2556.Tn BIOS . 2557See 2558.Xr pcibios 4 2559for details. 2560.It Cd options KSTACK_CHECK_DR0 2561Detect kernel stack overflow using DR0 register. 2562This option uses DR0 register exclusively so you can't use DR0 register for 2563other purpose (e.g., hardware breakpoint) if you turn this on. 2564.It Cd options MTRR 2565Include support for accessing MTRR registers from user-space. 2566See 2567.Xr i386_get_mtrr 2 . 2568.It Cd options BEEP_ONHALT 2569Make the system speaker emit several beeps when it is completely safe to 2570power down the computer after a 2571.Xr halt 8 2572command. 2573Requires 2574.Xr sysbeep 4 2575support. 2576.It Cd options BEEP_ONHALT_COUNT=times 2577Number of times to beep the speaker when 2578.Cd options BEEP_ONHALT 2579is enabled. 2580Defaults to 3. 2581.It Cd options BEEP_ONHALT_PITCH=hz 2582The tone frequency used when 2583.Cd options BEEP_ONHALT 2584option, in hertz. 2585Defaults to 1500. 2586.It Cd options BEEP_ONHALT_PERIOD=msecs 2587The duration of each beep when 2588.Cd options BEEP_ONHALT 2589is enabled, in milliseconds. 2590Defaults to 250. 2591.It Cd options MULTIBOOT 2592Makes the kernel Multiboot-compliant, allowing it to be booted through 2593a Multiboot-compliant boot manager such as GRUB. 2594See 2595.Xr multiboot 8 2596for more information. 2597.El 2598.Ss isa-specific Options 2599Options specific to 2600.Xr isa 4 2601busses. 2602.Bl -ohang 2603.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2604Control the section of IO bus space used for PCMCIA bus space mapping. 2605Ideally the probed defaults are satisfactory, however in practice 2606that is not always the case. 2607See 2608.Xr pcmcia 4 2609for details. 2610.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2611Controls the allowable interrupts that may be used for 2612.Tn PCMCIA 2613devices. 2614This mask is a logical-or of power-of-2s of allowable interrupts: 2615.Bd -literal -offset 04n 2616.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2617 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2618 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2619 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2620 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2621.Ed 2622.It Cd options PCKBC_CNATTACH_SELFTEST 2623Perform a self test of the keyboard controller before attaching it as a 2624console. 2625This might be necessary on machines where we boot on cold iron, and 2626pckbc refuses to talk until we request a self test. 2627Currently only the netwinder port uses it. 2628.It Cd options PCKBD_CNATTACH_MAY_FAIL 2629If this option is set the PS/2 keyboard will not be used as the console 2630if it cannot be found during boot. 2631This allows other keyboards, like USB, to be the console keyboard. 2632.It Cd options PCKBD_LAYOUT=layout 2633Sets the default keyboard layout, see 2634.Xr pckbd 4 . 2635.El 2636.Ss m68k-specific Options 2637.Bl -ohang 2638.It Cd options FPU_EMULATE 2639Include support for MC68881/MC68882 emulator. 2640.It Cd options FPSP 2641Include support for 68040 floating point. 2642.It Cd options M68020,M68030,M68040,M68060 2643Include support for a specific 2644.Tn CPU , 2645at least one (the one you are using) should be specified. 2646.It Cd options M060SP 2647Include software support for 68060. 2648This provides emulation of unimplemented 2649integer instructions as well as emulation of unimplemented floating point 2650instructions and data types and software support for floating point traps. 2651.El 2652.Ss powerpc-specific Options (OEA Only) 2653.Bl -ohang 2654.It Cd options PMAP_MEMLIMIT=value 2655Limit the amount of memory seen by the kernel to 2656.Ar value 2657bytes. 2658.It Cd options PTEGCOUNT=value 2659Specify the size of the page table as 2660.Ar value 2661PTE groups. 2662Normally, one PTEG is allocated per physical page frame. 2663.El 2664.Ss sparc-specific Options 2665.Bl -ohang 2666.It Cd options AUDIO_DEBUG 2667Enable simple event debugging of the logging of the 2668.Xr audio 4 2669device. 2670.It Cd options BLINK 2671Enable blinking of LED. 2672Blink rate is full cycle every N seconds for 2673N \*[Lt] then current load average. 2674See 2675.Xr getloadavg 3 . 2676.\" .It Cd options COLORFONT_CACHE 2677.\" What does this do? 2678.It Cd options COUNT_SW_LEFTOVERS 2679Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2680sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2681variables accessible from 2682.Xr ddb 4 . 2683See 2684.Xr sw 4 . 2685.It Cd options DEBUG_ALIGN 2686Adds debugging messages calls when user-requested alignment fault 2687handling happens. 2688.It Cd options DEBUG_EMUL 2689Adds debugging messages calls for emulated floating point and 2690alignment fixing operations. 2691.It Cd options DEBUG_SVR4 2692Prints registers messages calls for emulated SVR4 getcontext and 2693setcontext operations. 2694See 2695.Em options COMPAT_SVR4 . 2696.It Cd options EXTREME_DEBUG 2697Adds debugging functions callable from 2698.Xr ddb 4 . 2699The debug_pagetables, test_region and print_fe_map 2700functions print information about page tables for the SUN4M 2701platforms only. 2702.It Cd options EXTREME_EXTREME_DEBUG 2703Adds extra info to 2704.Em options EXTREME_DEBUG . 2705.It Cd options FPU_CONTEXT 2706Make 2707.Em options COMPAT_SVR4 2708getcontext and setcontext include floating point registers. 2709.It Cd options MAGMA_DEBUG 2710Adds debugging messages to the 2711.Xr magma 4 2712device. 2713.It Cd options RASTERCONS_FULLSCREEN 2714Use the entire screen for the console. 2715.It Cd options RASTERCONS_SMALLFONT 2716Use the Fixed font on the console, instead of the normal font. 2717.It Cd options SUN4 2718Support sun4 class machines. 2719.It Cd options SUN4C 2720Support sun4c class machines. 2721.It Cd options SUN4M 2722Support sun4m class machines. 2723.It Cd options SUN4_MMU3L 2724.\" XXX ??? 2725Enable support for sun4 3-level MMU machines. 2726.It Cd options V9 2727Enable SPARC V9 assembler in 2728.Xr ddb 4 . 2729.El 2730.Ss sparc64-specific Options 2731.Bl -ohang 2732.It Cd options AUDIO_DEBUG 2733Enable simple event debugging of the logging of the 2734.Xr audio 4 2735device. 2736.It Cd options BLINK 2737Enable blinking of LED. 2738Blink rate is full cycle every N seconds for 2739N \*[Lt] then current load average. 2740See 2741.Xr getloadavg 3 . 2742.El 2743.Ss x68k-specific Options 2744.Bl -ohang 2745.It Cd options EXTENDED_MEMORY 2746Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2747.It Cd options JUPITER 2748Include support for Jupiter-X MPU accelerator 2749.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2750Use the built-in serial port as the system-console. 2751Speed is specified in bps, defaults to 9600. 2752.It Cd options ITE_KERNEL_ATTR=value 2753Set the kernel message attribute for ITE. 2754Value, an integer, is a logical or of the following values: 2755.Bl -tag -width 4n -compact -offset indent 2756.It 1 2757color inversed 2758.It 2 2759underlined 2760.It 4 2761bolded 2762.El 2763.El 2764.\" The following requests should be uncommented and used where appropriate. 2765.\" .Sh FILES 2766.\" .Sh EXAMPLES 2767.Sh SEE ALSO 2768.Xr config 1 , 2769.Xr gdb 1 , 2770.Xr ktrace 1 , 2771.Xr pmc 1 , 2772.Xr quota 1 , 2773.Xr vndcompress 1 , 2774.Xr gettimeofday 2 , 2775.Xr i386_get_mtrr 2 , 2776.Xr i386_iopl 2 , 2777.Xr msgctl 2 , 2778.Xr msgget 2 , 2779.Xr msgrcv 2 , 2780.Xr msgsnd 2 , 2781.Xr ntp_adjtime 2 , 2782.Xr ntp_gettime 2 , 2783.Xr semctl 2 , 2784.Xr semget 2 , 2785.Xr semop 2 , 2786.Xr shmat 2 , 2787.Xr shmctl 2 , 2788.Xr shmdt 2 , 2789.Xr shmget 2 , 2790.Xr sysctl 3 , 2791.Xr apm 4 , 2792.Xr ddb 4 , 2793.Xr inet 4 , 2794.Xr iso 4 , 2795.Xr md 4 , 2796.Xr ns 4 , 2797.Xr pcibios 4 , 2798.Xr pcmcia 4 , 2799.Xr ppp 4 , 2800.Xr userconf 4 , 2801.Xr vnd 4 , 2802.Xr wscons 4 , 2803.Xr config 5 , 2804.Xr edquota 8 , 2805.Xr init 8 , 2806.Xr mdsetimage 8 , 2807.Xr mount_cd9660 8 , 2808.Xr mount_fdesc 8 , 2809.Xr mount_kernfs 8 , 2810.Xr mount_lfs 8 , 2811.Xr mount_mfs 8 , 2812.Xr mount_msdos 8 , 2813.Xr mount_nfs 8 , 2814.Xr mount_ntfs 8 , 2815.Xr mount_null 8 , 2816.Xr mount_portal 8 , 2817.Xr mount_procfs 8 , 2818.Xr mount_udf 8 , 2819.Xr mount_umap 8 , 2820.Xr mount_union 8 , 2821.Xr mrouted 8 , 2822.Xr newfs_lfs 8 , 2823.Xr ntpd 8 , 2824.Xr quotaon 8 , 2825.Xr rpc.rquotad 8 , 2826.Xr sysctl 8 , 2827.Xr in_getifa 9 2828.Sh HISTORY 2829The 2830.Nm 2831man page first appeared in 2832.Nx 1.3 . 2833.Sh BUGS 2834The 2835.Em EON 2836option should be a pseudo-device, and is also very fragile. 2837