1.\" $NetBSD: options.4,v 1.360 2008/01/16 09:37:04 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 January 15, 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 NVNODE=integer 1003This option sets the size of the cache used by the name-to-inode translation 1004routines, (a.k.a. the 1005.Fn namei 1006cache, though called by many other names in the kernel source). 1007By default, this cache has 1008.Dv NPROC 1009(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 1010A reasonable way to derive a value of 1011.Dv NVNODE , 1012should you notice a large number of namei cache misses with a tool such as 1013.Xr systat 1 , 1014is to examine your system's current computed value with 1015.Xr sysctl 8 , 1016(which calls this parameter "kern.maxvnodes") and to increase this value 1017until either the namei cache hit rate improves or it is determined that 1018your system does not benefit substantially from an increase in the size of 1019the namei cache. 1020.It Cd options NAMECACHE_ENTER_REVERSE 1021Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1022as well as a normal one. 1023Normally, this is already done for directory vnodes, to speed up the getcwd 1024operation. 1025This option will cause longer hash chains in the reverse cache, and thus 1026slow down getcwd somewhat. 1027However, it does make vnode -\*[Gt] path translations possible in some cases. 1028For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1029required. 1030.It Cd options EXT2FS_SYSTEM_FLAGS 1031This option changes the behavior of the APPEND and IMMUTABLE flags 1032for a file on an 1033.Em EXT2FS 1034file system. 1035Without this option, the superuser or owner of the file can 1036set and clear them. 1037With this option, only the superuser can set them, and 1038they can't be cleared if the securelevel is greater than 0. 1039See also 1040.Xr chflags 1 . 1041.It Cd options NFS_BOOT_BOOTP 1042Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1043information if NFS is used to mount the root file system. 1044See 1045.Xr diskless 8 1046for details. 1047.It Cd options NFS_BOOT_DHCP 1048Same as 1049.Dq NFS_BOOT_BOOTP , 1050but use the DHCP extensions to the 1051BOOTP protocol (RFC 1541). 1052.It Cd options NFS_BOOT_BOOTP_REQFILE 1053Specifies the string sent in the bp_file field of the BOOTP / DHCP 1054request packet. 1055.It Cd options NFS_BOOT_BOOTPARAM 1056Enable use of the BOOTPARAM protocol, consisting of RARP and 1057BOOTPARAM RPC, to get configuration information if NFS 1058is used to mount the root file system. 1059See 1060.Xr diskless 8 1061for details. 1062.It Cd options NFS_BOOT_RWSIZE=value 1063Set the initial NFS read and write sizes for diskless-boot requests. 1064The normal default is 8Kbytes. 1065This option provides a way to lower the value (e.g., to 1024 bytes) 1066as a workaround for buggy network interface cards or boot PROMs. 1067Once booted, the read and write request sizes can be increased by 1068remounting the file system. 1069See 1070.Xr mount_nfs 8 1071for details. 1072.It Cd options NFS_V2_ONLY 1073Reduce the size of the NFS client code by omitting code that's only required 1074for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1075servers. 1076.It Cd options SOFTDEP 1077Enable kernel support for soft-dependencies in FFS file systems. 1078Softdep improves write performance by aggregating and properly 1079ordering disk metadata writes, achieving near-asynchronous write 1080performance while maintaining the file system consistency of 1081synchronous writes. 1082Soft-dependencies are enabled on a per-mount basis. 1083See 1084.Xr mount 8 1085for details. 1086.It Cd options UFS_DIRHASH 1087Increase lookup performance by maintaining in-core hash tables 1088for large directories. 1089.El 1090.Ss Buffer queue strategy options 1091The following options enable alternative buffer queue strategies. 1092.Bl -ohang 1093.It Cd options BUFQ_READPRIO 1094Enable experimental buffer queue strategy for disk I/O. 1095In the default strategy, outstanding disk requests are ordered by 1096sector number and sent to the disk, regardless of whether the 1097operation is a read or write; this option gives priority to issuing 1098read requests over write requests. 1099Although requests may therefore be issued out of sector-order, causing 1100more seeks and thus lower overall throughput, interactive system 1101responsiveness under heavy disk I/O load may be improved, as processes 1102blocking on disk reads are serviced sooner (file writes typically 1103don't cause applications to block). 1104The performance effect varies greatly depending on the hardware, drive 1105firmware, file system configuration, workload, and desired performance 1106trade-off. 1107Systems using drive write-cache (most modern IDE disks, by default) 1108are unlikely to benefit and may well suffer; such disks acknowledge 1109writes very quickly, and optimize them internally according to 1110physical layout. 1111Giving these disks as many requests to work with as possible (the 1112standard strategy) will typically produce the best results, especially 1113if the drive has a large cache; the drive will silently complete 1114writes from cache as it seeks for reads. 1115Disks that support a large number of concurrent tagged requests (SCSI 1116disks and many hardware RAID controllers) expose this internal 1117scheduling with tagged responses, and don't block for reads; such 1118disks may not see a noticeable difference with either strategy. 1119However, if IDE disks are run with write-cache disabled for safety, 1120writes are not acknowledged until actually completed, and only one 1121request can be outstanding; a large number of small writes in one 1122locality can keep the disk busy, starving reads elsewhere on the disk. 1123Such systems are likely to see the most benefit from this option. 1124Finally, the performance interaction of this option with ffs soft 1125dependencies can be subtle, as that mechanism can drastically alter 1126the workload for file system metadata writes. 1127.It Cd options BUFQ_PRIOCSCAN 1128Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1129.It Cd options NEW_BUFQ_STRATEGY 1130Synonym of 1131.Em BUFQ_READPRIO . 1132.El 1133.Ss Miscellaneous Options 1134.Bl -ohang 1135.It Cd options LKM 1136Enable loadable kernel modules. 1137See 1138.Xr lkm 4 1139for details. 1140.Em NOTE : 1141not available on all architectures. 1142.It Cd options MEMORY_DISK_DYNAMIC 1143This option makes the 1144.Xr md 4 1145.Tn RAM 1146disk size dynamically sized. 1147It is incompatible with 1148.Xr mdsetimage 8 . 1149.It Cd options MEMORY_DISK_HOOKS 1150This option allows for some machine dependent functions to be called when 1151the 1152.Xr md 4 1153.Tn RAM 1154disk driver is configured. 1155This can result in automatically loading a 1156.Tn RAM 1157disk from floppy on open (among other things). 1158.It Cd options MEMORY_DISK_IS_ROOT 1159Forces the 1160.Xr md 4 1161.Tn RAM 1162disk to be the root device. 1163This can only be overridden when 1164the kernel is booted in the 'ask-for-root' mode. 1165.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1166Allocates the given number of 512 byte blocks as memory for the 1167.Xr md 4 1168.Tn RAM 1169disk, to be populated with 1170.Xr mdsetimage 8 . 1171.It Cd options MEMORY_DISK_SERVER=0 1172Do not include the interface to a userland memory disk server process. 1173Per default, this option is set to 1, including the support code. 1174Useful for install media kernels. 1175.It Cd options VND_COMPRESSION 1176Enables the 1177.Xr vnd 4 1178driver to also handle compressed images. 1179See 1180.Xr vndcompress 1 , 1181.Xr vnd 4 1182and 1183.Xr vnconfig 8 1184for more information. 1185.It Cd options TFTPROOT 1186Download the root memory disk through TFTP at root mount time. 1187This enables the use of a root 1188.Tn RAM 1189disk without requiring it to be embedded in the kernel using 1190.Xr mdsetimage 8 . 1191The 1192.Tn RAM 1193disk name is obtained using DHCP's filename parameter. 1194This option requires 1195.Em MEMORY_DISK_HOOKS , 1196.Em MEMORY_DISK_DYNAMIC , 1197and 1198.Em MEMORY_DISK_IS_ROOT . 1199It is incompatible with 1200.Em MEMORY_DISK_ROOT_SIZE . 1201.It Cd options MALLOC_NOINLINE 1202Time critical fixed size memory allocation is performed with 1203.Fn MALLOC 1204and 1205.Fn FREE . 1206Normally these expand to inline code, but with 1207.Em MALLOC_NOINLINE 1208these call the normal 1209.Fn malloc 1210and 1211.Fn free 1212functions. 1213Useful for install media kernels, small memory systems and embedded systems. 1214.It Cd options HZ=integer 1215On ports that support it, set the system clock frequency (see 1216.Xr hz 9 ) 1217to the supplied value. 1218Handle with care. 1219.It Cd options NTP 1220Turns on in-kernel precision timekeeping support used by software 1221implementing 1222.Em NTP 1223(Network Time Protocol, RFC 1305). 1224The 1225.Em NTP 1226option adds an in-kernel Phase-Locked Loop (PLL) for normal 1227.Em NTP 1228operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1229operation. 1230.Xr ntpd 8 1231will employ a user-level PLL when kernel support is unavailable, 1232but the in-kernel version has lower latency and more precision, and 1233so typically keeps much better time. 1234The interface to the kernel 1235.Em NTP 1236support is provided by the 1237.Xr ntp_adjtime 2 1238and 1239.Xr ntp_gettime 2 1240system calls, which are intended for use by 1241.Xr ntpd 8 1242and are enabled by the option. 1243On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1244is not an integer, the 1245.Em NTP 1246option also enables extended-precision arithmetic to keep track of 1247fractional clock ticks at NTP time-format precision. 1248.It Cd options PPS_SYNC 1249This option enables a kernel serial line discipline for receiving time 1250phase signals from an external reference clock such as a radio clock. 1251(The 1252.Em NTP 1253option (which see) must be on if the 1254.Em PPS_SYNC 1255option is used.) 1256Some reference clocks generate a Pulse Per Second (PPS) signal in 1257phase with their time source. 1258The 1259.Em PPS 1260line discipline receives this signal on either the data leads 1261or the DCD control lead of a serial port. 1262.Em NTP 1263uses the PPS signal to discipline the local clock oscillator to a high 1264degree of precision (typically less than 50 microseconds in time and 12650.1 ppm in accuracy). 1266.Em PPS 1267can also generate a serial output pulse when the system receives a PPS 1268interrupt. 1269This can be used to measure the system interrupt latency and thus calibrate 1270.Em NTP 1271to account for it. 1272Using 1273.Em PPS 1274usually requires a 1275gadget box 1276to convert from TTL to RS-232 signal levels. 1277The gadget box and PPS are described in more detail in the HTML documentation 1278for 1279.Xr ntpd 8 1280in 1281.Pa /usr/share/doc/html/ntp . 1282.It Cd options NO_TSC_TIME 1283Don't use TSC microtime, even if available (i386 only). 1284Improves time behavior under VMware. 1285.It Cd options SETUIDSCRIPTS 1286Allows scripts with the setuid bit set to execute as the effective 1287user rather than the real user, just like binary executables. 1288.Pp 1289.Em NOTE : 1290Using this option will also enable 1291.Em options FDSCRIPTS 1292.It Cd options FDSCRIPTS 1293Allows execution of scripts with the execute bit set, but not the 1294read bit, by opening the file and passing the file descriptor to 1295the shell, rather than the filename. 1296.Pp 1297.Em NOTE : 1298Execute only (non-readable) scripts will have 1299.Va argv[0] 1300set to 1301.Pa /dev/fd/* . 1302What this option allows as far as security is 1303concerned, is the ability to safely ensure that the correct script 1304is run by the interpreter, as it is passed as an already open file. 1305.It Cd options PUCCN 1306Enables treating serial ports found on PCI boards 1307.Xr puc 4 1308as potential console devices. 1309The method for choosing such a console device is port dependent. 1310.It Cd options RTC_OFFSET=integer 1311The kernel (and typically the hardware battery backed-up clock on 1312those machines that have one) keeps time in 1313.Em UTC 1314(Universal Coordinated Time, once known as 1315.Em GMT , 1316or Greenwich Mean Time) 1317and not in the time of the local time zone. 1318The 1319.Em RTC_OFFSET 1320option is used on some ports (such as the i386) to tell the kernel 1321that the hardware clock is offset from 1322.Em UTC 1323by the specified number of minutes. 1324This is typically used when a machine boots several operating 1325systems and one of them wants the hardware clock to run in the 1326local time zone and not in 1327.Em UTC , 1328e.g. 1329.Em RTC_OFFSET=300 1330means 1331the hardware clock is set to US Eastern Time (300 minutes behind 1332.Em UTC ) , 1333and not 1334.Em UTC . 1335(Note: 1336.Em RTC_OFFSET 1337is used to initialize a kernel variable named 1338.Va rtc_offset 1339which is the source actually used to determine the clock offset, and 1340which may be accessed via the kern.rtc_offset sysctl variable. 1341See 1342.Xr sysctl 8 1343and 1344.Xr sysctl 3 1345for details. 1346Since the kernel clock is initialized from the hardware clock very 1347early in the boot process, it is not possible to meaningfully change 1348.Va rtc_offset 1349in system initialization scripts. 1350Changing this value currently may only be done at kernel compile 1351time or by patching the kernel and rebooting). 1352.Pp 1353.Em NOTE : 1354Unfortunately, in many cases where the hardware clock 1355is kept in local time, it is adjusted for Daylight Savings 1356Time; this means that attempting to use 1357.Em RTC_OFFSET 1358to let 1359.Nx 1360coexist with such an operating system, like Windows, 1361would necessitate changing 1362.Em RTC_OFFSET 1363twice a year. 1364As such, this solution is imperfect. 1365.It Cd options KMEMSTATS 1366The kernel memory allocator, 1367.Xr malloc 9 , 1368will keep statistics on its performance if this option is enabled. 1369Unfortunately, this option therefore essentially disables the 1370.Fn MALLOC 1371and 1372.Fn FREE 1373forms of the memory allocator, which are used to enhance the performance 1374of certain critical sections of code in the kernel. 1375This option therefore can lead to a significant decrease in the 1376performance of certain code in the kernel if enabled. 1377Examples of such code include the 1378.Fn namei 1379routine, the 1380.Xr ccd 4 1381driver, 1382and much of the networking code. 1383.It Cd options MAXUPRC=integer 1384Sets the soft 1385.Dv RLIMIT_NPROC 1386resource limit, which specifies the maximum number of simultaneous 1387processes a user is permitted to run, for process 0; 1388this value is inherited by its child processes. 1389It defaults to 1390.Em CHILD_MAX , 1391which is currently defined to be 160. 1392Setting 1393.Em MAXUPRC 1394to a value less than 1395.Em CHILD_MAX 1396is not permitted, as this would result in a violation of the semantics of 1397.St -p1003.1-90 . 1398.It Cd options NOFILE=integer 1399Sets the soft 1400.Dv RLIMIT_NOFILE 1401resource limit, which specifies the maximum number of open 1402file descriptors for each process; 1403this value is inherited by its child processes. 1404It defaults to 1405.Em OPEN_MAX , 1406which is currently defined to be 64. 1407.It Cd options MAXFILES=integer 1408Sets the default value of the 1409.Em kern.maxfiles 1410sysctl variable, which indicates the maximum number of files that may 1411be open in the system. 1412.It Cd options DEFCORENAME=string 1413Sets the default value of the 1414.Em kern.defcorename 1415sysctl variable, otherwise it is set to 1416.Nm %n.core . 1417See 1418.Xr sysctl 8 1419and 1420.Xr sysctl 3 1421for details. 1422.It Cd options RASOPS_CLIPPING 1423Enables clipping within the 1424.Nm rasops 1425raster-console output system. 1426.Em NOTE : 1427only available on architectures that use 1428.Nm rasops 1429for console output. 1430.It Cd options RASOPS_SMALL 1431Removes optimized character writing code from the 1432.Nm rasops 1433raster-console output system. 1434.Em NOTE : 1435only available on architectures that use 1436.Nm rasops 1437for console output. 1438.It Cd options INCLUDE_CONFIG_FILE 1439Embeds the kernel config file used to define the kernel in the kernel 1440binary itself. 1441The embedded data also includes any files directly included by the config 1442file itself, e.g. 1443.Pa GENERIC.local 1444or 1445.Pa std.$MACHINE . 1446The embedded config file can be extracted from the resulting kernel with 1447.Xr config 1 1448.Fl x , 1449or by the following command: 1450.Bd -literal -offset indent 1451strings netbsd | sed -n 's/^_CFG_//p' | unvis 1452.Ed 1453.It Cd options INCLUDE_JUST_CONFIG 1454Similar to the above option, but includes just the actual config file, 1455not any included files. 1456.It Cd options PIPE_SOCKETPAIR 1457Use slower, but smaller socketpair(2)-based pipe implementation instead 1458of default faster, but bigger one. 1459Primarily useful for installation kernels. 1460.It Cd options USERCONF 1461Compiles in the in-kernel device configuration manager. 1462See 1463.Xr userconf 4 1464for details. 1465.It Cd options PERFCTRS 1466Compiles in kernel support for CPU performance-monitoring counters. 1467See 1468.Xr pmc 1 1469for details. 1470.Em NOTE : 1471not available on all architectures. 1472.It Cd options SYSCALL_STATS 1473Count the number of times each system call number is called. 1474The values can be read through the sysctl interface and displayed using 1475.Xr systat 1 . 1476.Em NOTE : 1477not yet available on all architectures. 1478.It Cd options SYSCALL_TIMES 1479Count the time spent (using 1480.Fn cpu_counter32 ) 1481in each system call. 1482.Em NOTE : 1483Using this option will also enable 1484.Cd options SYSCALL_STATS . 1485.It Cd options SYSCALL_TIMES_HASCOUNTER 1486Force use of 1487.Fn cpu_counter32 1488even if 1489.Fn cpu_hascounter 1490reports false. 1491Useful for systems where the cycle counter doesn't run at a constant rate 1492(e.g. Soekris boxes). 1493.It Cd options XSERVER 1494Compiles in kernel support for 1495.Tn X11 1496on architectures that still use (or can use) the legacy 1497.Em pccons 1498console drivers rather than 1499.Xr wscons 4 . 1500These include bebox, i386, shark. 1501.It Cd options XSERVER_DDB 1502A supplement to XSERVER that adds support for entering 1503.Xr ddb 4 1504while in 1505.Tn X11 . 1506.It Cd options FILEASSOC 1507Support for 1508.Xr fileassoc 9 . 1509.It Cd options FILEASSOC_NHOOKS=integer 1510Number of storage slots per file for 1511.Xr fileassoc 9 . 1512Default is 4. 1513.El 1514.Ss Networking Options 1515.Bl -ohang 1516.It Cd options GATEWAY 1517Enables 1518.Em IPFORWARDING 1519(which see) 1520and (on most ports) increases the size of 1521.Em NMBCLUSTERS 1522(which see). 1523In general, 1524.Em GATEWAY 1525is used to indicate that a system should act as a router, and 1526.Em IPFORWARDING 1527is not invoked directly. 1528(Note that 1529.Em GATEWAY 1530has no impact on protocols other than 1531.Tn IP , 1532such as 1533.Tn CLNP 1534or 1535.Tn XNS ) . 1536.Em GATEWAY 1537option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1538.It Cd options ICMPPRINTFS 1539The 1540.Em ICMPPRINTFS 1541option will enable debugging information to be printed about 1542the 1543.Xr icmp 4 1544protocol. 1545.It Cd options IPFORWARDING=value 1546If 1547.Em value 1548is 1 this enables IP routing behavior. 1549If 1550.Em value 1551is 0 (the default), it disables it. 1552The 1553.Em GATEWAY 1554option sets this to 1 automatically. 1555With this option enabled, the machine will forward IP datagrams destined 1556for other machines between its interfaces. 1557Note that even without this option, the kernel will 1558still forward some packets (such as source routed packets) -- removing 1559.Em GATEWAY 1560and 1561.Em IPFORWARDING 1562is insufficient to stop all routing through a bastion host on a 1563firewall -- source routing is controlled independently. 1564To turn off source routing, use 1565.Em options IPFORWSRCRT=0 1566(which see). 1567Note that IP forwarding may be turned on and off independently of the 1568setting of the 1569.Em IPFORWARDING 1570option through the use of the 1571.Em net.inet.ip.forwarding 1572sysctl variable. 1573If 1574.Em net.inet.ip.forwarding 1575is 1, IP forwarding is on. 1576See 1577.Xr sysctl 8 1578and 1579.Xr sysctl 3 1580for details. 1581.It Cd options IPFORWSRCRT=value 1582If 1583.Em value 1584is set to zero, source routing of IP datagrams is turned off. 1585If 1586.Em value 1587is set to one (the default) or the option is absent, source routed IP 1588datagrams are forwarded by the machine. 1589Note that source routing of IP packets may be turned on and off 1590independently of the setting of the 1591.Em IPFORWSRCRT 1592option through the use of the 1593.Em net.inet.ip.forwsrcrt 1594sysctl variable. 1595If 1596.Em net.inet.ip.forwsrcrt 1597is 1, forwarding of source routed IP datagrams is on. 1598See 1599.Xr sysctl 8 1600and 1601.Xr sysctl 3 1602for details. 1603.It Cd options IFA_STATS 1604Tells the kernel to maintain per-address statistics on bytes sent 1605and received over (currently) Internet and AppleTalk addresses. 1606.\"This can be a fairly expensive operation, so you probably want to 1607.\"keep this disabled. 1608The option is not recommended as it degrades system stability. 1609.It Cd options IFQ_MAXLEN=value 1610Increases the allowed size of the network interface packet queues. 1611The default queue size is 50 packets, and you do not normally need 1612to increase it. 1613.It Cd options IPSELSRC 1614Includes support for source-address selection policies. 1615See 1616.Xr in_getifa 9 . 1617.It Cd options MROUTING 1618Includes support for IP multicast routers. 1619You certainly want 1620.Em INET 1621with this. 1622Multicast routing is controlled by the 1623.Xr mrouted 8 1624daemon. 1625See also option 1626.Cd PIM . 1627.It Cd options PIM 1628Includes support for Protocol Independent Multicast (PIM) routing. 1629You need 1630.Em MROUTING 1631and 1632.Em INET 1633with this. 1634Software using this can be found e.g. in 1635.Pa pkgsrc/net/xorp . 1636.It Cd options INET 1637Includes support for the 1638.Tn TCP/IP 1639protocol stack. 1640You almost certainly want this. 1641See 1642.Xr inet 4 1643for details. 1644.It Cd options INET6 1645Includes support for the 1646.Tn IPv6 1647protocol stack. 1648See 1649.Xr inet6 4 1650for details. 1651Unlike 1652.Em INET , 1653.Em INET6 1654enables multicast routing code as well. 1655This option requires 1656.Em INET 1657at this moment, but it should not. 1658.It Cd options ND6_DEBUG 1659The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1660for debugging IPv6 neighbor discovery protocol handling. 1661See 1662.Xr sysctl 3 1663for details. 1664.It Cd options IPSEC 1665Includes support for the 1666.Tn IPsec 1667protocol. 1668See 1669.Xr ipsec 4 1670for details. 1671.It Cd options IPSEC_DEBUG 1672Enables debugging code in 1673.Tn IPsec 1674stack. 1675See 1676.Xr ipsec 4 1677for details. 1678.It Cd options IPSEC_ESP 1679Includes support for 1680.Tn IPsec 1681.Tn ESP 1682protocol. 1683See 1684.Xr ipsec 4 1685for details. 1686.It Cd options IPSEC_NAT_T 1687Includes support for 1688.Tn IPsec 1689Network Address Translator traversal (NAT-T), as described in RFCs 3947 1690and 3948. 1691This feature might be patent-encumbered in some countries. 1692.It Cd options ALTQ 1693Enabled ALTQ (Alternate Queueing). 1694For simple rate-limiting, use 1695.Xr tbrconfig 8 1696to set up the interface transmission rate. 1697To use queueing disciplines, their appropriate kernel options should also 1698be defined (documented below). 1699Queueing disciplines are managed by 1700.Xr altqd 8 . 1701See 1702.Xr altq 9 1703for details. 1704.It Cd options ALTQ_HFSC 1705Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1706module. 1707HFSC supports both link-sharing and guaranteed real-time services. 1708HFSC employs a service curve based QoS model, and its unique feature 1709is an ability to decouple delay and bandwidth allocation. 1710Requires 1711.Em ALTQ_RED 1712to use the RED queueing discipline on HFSC classes, or 1713.Em ALTQ_RIO 1714to use the RIO queueing discipline on HFSC classes. 1715This option assumes 1716.Em ALTQ . 1717.It Cd options ALTQ_PRIQ 1718Include support for ALTQ-implemented PRIQ (Priority Queueing). 1719PRIQ implements a simple priority-based queueing discipline. 1720A higher priority class is always served first. 1721Requires 1722.Em ALTQ_RED 1723to use the RED queueing discipline on HFSC classes, or 1724.Em ALTQ_RIO 1725to use the RIO queueing discipline on HFSC classes. 1726This option assumes 1727.Em ALTQ . 1728.It Cd options ALTQ_WFQ 1729Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1730WFQ implements a weighted-round robin scheduler for a set of queues. 1731A weight can be assigned to each queue to give a different proportion 1732of the link capacity. 1733A hash function is used to map a flow to one of a set of queues. 1734This option assumes 1735.Em ALTQ . 1736.It Cd options ALTQ_FIFOQ 1737Include support for ALTQ-implemented FIFO queueing. 1738FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1739This option assumes 1740.Em ALTQ . 1741.It Cd options ALTQ_RIO 1742Include support for ALTQ-implemented RIO (RED with In/Out). 1743The original RIO has 2 sets of RED parameters; one for in-profile 1744packets and the other for out-of-profile packets. 1745At the ingress of the network, profile meters tag packets as IN or 1746OUT based on contracted profiles for customers. 1747Inside the network, IN packets receive preferential treatment by 1748the RIO dropper. 1749ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1750PHB of DiffServ (RFC 2597). 1751This option assumes 1752.Em ALTQ . 1753.It Cd options ALTQ_BLUE 1754Include support for ALTQ-implemented Blue buffer management. 1755Blue is another active buffer management mechanism. 1756This option assumes 1757.Em ALTQ . 1758.It Cd options ALTQ_FLOWVALVE 1759Include support for ALTQ-implemented Flowvalve. 1760Flowvalve is a simple implementation of a RED penalty box that identifies 1761and punishes misbehaving flows. 1762This option requires 1763.Em ALTQ_RED 1764and assumes 1765.Em ALTQ . 1766.It Cd options ALTQ_CDNR 1767Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1768packet marking/manipulation. 1769Traffic conditioners are components to meter, mark, or drop incoming 1770packets according to some rules. 1771As opposed to queueing disciplines, traffic conditioners handle incoming 1772packets at an input interface. 1773This option assumes 1774.Em ALTQ . 1775.It Cd options ALTQ_NOPCC 1776Disables use of processor cycle counter to measure time in ALTQ. 1777This option should be defined for a non-Pentium i386 CPU which does not 1778have TSC, SMP (per-CPU counters are not in sync), or power management 1779which affects processor cycle counter. 1780This option assumes 1781.Em ALTQ . 1782.It Cd options ALTQ_IPSEC 1783Include support for IPsec in IPv4 ALTQ. 1784This option assumes 1785.Em ALTQ . 1786.It Cd options ALTQ_JOBS 1787Include support for ALTQ-implemented JoBS (Joint Buffer Management 1788and Scheduling). 1789This option assumes 1790.Em ALTQ . 1791.It Cd options ALTQ_AFMAP 1792Include support for an undocumented ALTQ feature that is used to map an IP 1793flow to an ATM VC (Virtual Circuit). 1794This option assumes 1795.Em ALTQ . 1796.It Cd options ALTQ_LOCALQ 1797Include support for ALTQ-implemented local queues. 1798Its practical use is undefined. 1799Assumes 1800.Em ALTQ . 1801.It Cd options SUBNETSARELOCAL 1802Sets default value for net.inet.ip.subnetsarelocal variable, which 1803controls whether non-directly-connected subnets of connected networks 1804are considered "local" for purposes of choosing the MSS for a TCP 1805connection. 1806This is mostly present for historic reasons and completely irrelevant if 1807you enable Path MTU discovery. 1808.It Cd options HOSTZEROBROADCAST 1809Sets default value for net.inet.ip.hostzerobroadcast variable, which 1810controls whether the zeroth host address of each connected subnet is 1811also considered a broadcast address. 1812Default value is "1", for compatibility with old systems; if this is 1813set to zero on all hosts on a subnet, you should be able to fit an extra 1814host per subnet on the 1815".0" address. 1816.It Cd options MCLSHIFT=value 1817This option is the base-2 logarithm of the size of mbuf clusters. 1818The 1819.Bx 1820networking stack keeps network packets in a linked 1821list, or chain, of kernel buffer objects called mbufs. 1822The system provides larger mbuf clusters as an optimization for 1823large packets, instead of using long chains for large packets. 1824The mbuf cluster size, 1825or 1826.Em MCLBYTES , 1827must be a power of two, and is computed as two raised to the power 1828.Em MCLSHIFT . 1829On systems with Ethernet network adapters, 1830.Em MCLSHIFT 1831is often set to 11, giving 2048-byte mbuf clusters, large enough to 1832hold a 1500-byte 1833.Tn Ethernet 1834frame in a single cluster. 1835Systems with network interfaces supporting larger frame sizes like 1836.Tn ATM , 1837.Tn FDDI , 1838or 1839.Tn HIPPI 1840may perform better with 1841.Em MCLSHIFT 1842set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1843respectively. 1844.It Cd options NS 1845Include support for the 1846.Tn Xerox 1847.Tn XNS 1848protocol stack. 1849See 1850.Xr ns 4 1851for details. 1852.It Cd options ISO,TPIP 1853Include support for the ubiquitous 1854.Tn OSI 1855protocol stack. 1856See 1857.Xr iso 4 1858for details. 1859This option assumes 1860.Em INET . 1861.It Cd options EON 1862Include support for tunneling 1863.Tn OSI 1864protocols over 1865.Tn IP . 1866Known to be broken, or at least very fragile, and undocumented. 1867.It Cd options NETATALK 1868Include support for the 1869.Tn AppleTalk 1870protocol stack. 1871The kernel provides provision for the 1872.Em Datagram Delivery Protocol 1873(DDP), providing SOCK_DGRAM support and 1874.Tn AppleTalk 1875routing. 1876This stack is used by the 1877.Em NETATALK 1878package, which adds support for 1879.Tn AppleTalk 1880server services via user libraries and applications. 1881.It Cd options BLUETOOTH 1882Include support for the 1883.Tn Bluetooth 1884protocol stack. 1885See 1886.Xr bluetooth 4 1887for details. 1888.It Cd options IPNOPRIVPORTS 1889Normally, only root can bind a socket descriptor to a so-called 1890.Dq privileged 1891.Tn TCP 1892port, that is, a port number in the range 0-1023. 1893This option eliminates those checks from the kernel. 1894This can be useful if there is a desire to allow daemons without 1895privileges to bind those ports, e.g., on firewalls. 1896The security tradeoffs in doing this are subtle. 1897This option should only be used by experts. 1898.It Cd options TCP_COMPAT_42 1899.Tn TCP 1900bug compatibility with 1901.Bx 4.2 . 1902In 1903.Bx 4.2 , 1904.Tn TCP 1905sequence numbers were 32-bit signed values. 1906Modern implementations of TCP use unsigned values. 1907This option clamps the initial sequence number to start in 1908the range 2^31 rather than the full unsigned range of 2^32. 1909Also, under 1910.Bx 4.2 , 1911keepalive packets must contain at least one byte or else 1912the remote end would not respond. 1913.It Cd options TCP_DEBUG 1914Record the last 1915.Em TCP_NDEBUG 1916TCP packets with SO_DEBUG set, and decode to the console if 1917.Em tcpconsdebug 1918is set. 1919.It Cd options TCP_NDEBUG 1920Number of packets to record for 1921.Em TCP_DEBUG . 1922Defaults to 100. 1923.It Cd options TCP_SENDSPACE=value 1924.It Cd options TCP_RECVSPACE=value 1925These options set the max TCP window size to other sizes than the default. 1926The TCP window sizes can be altered via 1927.Xr sysctl 8 1928as well. 1929.It Cd options TCP_INIT_WIN=value 1930This option sets the initial TCP window size for non-local connections, 1931which is used when the transmission starts. 1932The default size is 1, but if the machine should act more aggressively, 1933the initial size can be set to some other value. 1934The initial TCP window size can be set via 1935.Xr sysctl 8 1936as well. 1937.It Cd options PFIL_HOOKS 1938This option turns on the packet filter interface hooks. 1939See 1940.Xr pfil 9 1941for details. 1942This option assumes 1943.Em INET . 1944.It Cd options IPFILTER_LOG 1945This option, in conjunction with 1946.Em pseudo-device ipfilter , 1947enables logging of IP packets using ip-filter. 1948.It Cd options IPFILTER_DEFAULT_BLOCK 1949This option sets the default policy of ip-filter. 1950If it is set, ip-filter will block packets by default. 1951.It Cd options BRIDGE_IPF 1952This option causes 1953.Em bridge 1954devices to use the IP and/or IPv6 filtering hooks, forming 1955a link-layer filter that uses protocol-layer rules. 1956This option assumes the presence of 1957.Em pseudo-device ipfilter . 1958.It Cd options MBUFTRACE 1959This option can help track down mbuf leaks. 1960When enabled, mbufs are tagged with the devices and protocols using them, 1961which slightly decreases network performance. 1962This additional information can be viewed with 1963.Xr netstat 1 : 1964.Dl Ic netstat Fl mssv 1965Not all devices or protocols support this option. 1966.El 1967.Ss Sysctl Related Options 1968.Bl -ohang 1969.It Cd options SYSCTL_DISALLOW_CREATE 1970Disallows the creation or deletion of nodes from the sysctl tree, as 1971well as the assigning of descriptions to nodes that lack them, by any 1972process. 1973These operations are still available to kernel sub-systems, including 1974loadable kernel modules. 1975.It Cd options SYSCTL_DISALLOW_KWRITE 1976Prevents processes from adding nodes to the sysctl tree that make 1977existing kernel memory areas writable. 1978Sections of kernel memory can still be read and new nodes that own 1979their own data may still be writable. 1980.It Cd options SYSCTL_DEBUG_SETUP 1981Causes the SYSCTL_SETUP routines to print a brief message when they 1982are invoked. 1983This is merely meant as an aid in determining the order in which 1984sections of the tree are created. 1985.It Cd options SYSCTL_DEBUG_CREATE 1986Prints a message each time 1987.Fn sysctl_create , 1988the function that adds nodes to the tree, is called. 1989.It Cd options SYSCTL_INCLUDE_DESCR 1990Causes the kernel to include short, human readable descriptions for 1991nodes in the sysctl tree. 1992The descriptions can be retrieved programmatically (see 1993.Xr sysctl 3 ) , 1994or by the sysctl binary itself (see 1995.Xr sysctl 8 ) . 1996The descriptions are meant to give an indication of the purpose and/or 1997effects of a given node's value, not replace the documentation for the 1998given subsystem as a whole. 1999.El 2000.Ss System V IPC Options 2001.Bl -ohang 2002.It Cd options SYSVMSG 2003Includes support for 2004.At V 2005style message queues. 2006See 2007.Xr msgctl 2 , 2008.Xr msgget 2 , 2009.Xr msgrcv 2 , 2010.Xr msgsnd 2 . 2011.It Cd options SYSVSEM 2012Includes support for 2013.At V 2014style semaphores. 2015See 2016.Xr semctl 2 , 2017.Xr semget 2 , 2018.Xr semop 2 . 2019.It Cd options SEMMNI=value 2020Sets the number of 2021.At V 2022style semaphore identifiers. 2023The GENERIC config file for your port will have the default. 2024.It Cd options SEMMNS=value 2025Sets the number of 2026.At V 2027style semaphores in the system. 2028The GENERIC config file for your port will have the default. 2029.It Cd options SEMUME=value 2030Sets the maximum number of undo entries per process for 2031.At V 2032style semaphores. 2033The GENERIC config file for your port will have the default. 2034.It Cd options SEMMNU=value 2035Sets the number of undo structures in the system for 2036.At V 2037style semaphores. 2038The GENERIC config file for your port will have the default. 2039.It Cd options SYSVSHM 2040Includes support for 2041.At V 2042style shared memory. 2043See 2044.Xr shmat 2 , 2045.Xr shmctl 2 , 2046.Xr shmdt 2 , 2047.Xr shmget 2 . 2048.It Cd options SHMMAXPGS=value 2049Sets the maximum number of 2050.At V 2051style shared memory pages that are available through the 2052.Xr shmget 2 2053system call. 2054Default value is 1024 on most ports. 2055See 2056.Pa /usr/include/machine/vmparam.h 2057for the default. 2058.El 2059.Ss VM Related Options 2060.Bl -ohang 2061.It Cd options NMBCLUSTERS=value 2062The number of mbuf clusters the kernel supports. 2063Mbuf clusters are MCLBYTES in size (usually 2k). 2064This is used to compute the size of the kernel VM map 2065.Em mb_map , 2066which maps mbuf clusters. 2067Default on most ports is 1024 (2048 with 2068.Dq options GATEWAY 2069). 2070See 2071.Pa /usr/include/machine/param.h 2072for exact default information. 2073Increase this value if you get 2074.Dq mclpool limit reached 2075messages. 2076.It Cd options NKMEMPAGES=value 2077.It Cd options NKMEMPAGES_MIN=value 2078.It Cd options NKMEMPAGES_MAX=value 2079Size of kernel VM map 2080.Em kmem_map , 2081in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2082from the 2083.Xr sysctl 8 2084variable 2085.Em hw.pagesize 2086). 2087This VM map is used to map the kernel malloc arena. 2088The kernel attempts to auto-size this map based on the amount of 2089physical memory in the system. 2090Platform-specific code may place bounds on this computed size, 2091which may be viewed with the 2092.Xr sysctl 8 2093variable 2094.Em vm.nkmempages . 2095See 2096.Pa /usr/include/machine/param.h 2097for the default upper and lower bounds. 2098The related options 2099.Sq NKMEMPAGES_MIN 2100and 2101.Sq NKMEMPAGES_MAX 2102allow the bounds to be overridden in the kernel configuration file. 2103These options are provided in the event the computed value is 2104insufficient resulting in an 2105.Dq out of space in kmem_map 2106panic. 2107.It Cd options SB_MAX=value 2108Sets the max size in bytes that a socket buffer is allowed to occupy. 2109The default is 256k, but sometimes it needs to be increased, for example 2110when using large TCP windows. 2111This option can be changed via 2112.Xr sysctl 8 2113as well. 2114.It Cd options SOMAXKVA=value 2115Sets the maximum size of kernel virtual memory that the socket buffers 2116are allowed to use. 2117The default is 16MB, but in situations where for example large TCP 2118windows are used this value must also be increased. 2119This option can be changed via 2120.Xr sysctl 8 2121as well. 2122.It Cd options BUFCACHE=value 2123Size of the buffer cache as a percentage of total available 2124.Tn RAM . 2125Ignored if BUFPAGES is also specified. 2126.It Cd options NBUF=value 2127Sets the number of buffer headers available, i.e., the number of 2128open files that may have a buffer cache entry. 2129Each buffer header 2130requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2131The default value is machine dependent, but is usually equal to the 2132value of BUFPAGES. 2133If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2134then NBUF may be reduced at run time so that the storage allocated 2135for buffer headers doesn't exceed that limit. 2136.It Cd options BUFPAGES=value 2137These options set the number of pages available for the buffer cache. 2138Their default value is a machine dependent value, often calculated as 2139between 5% and 10% of total available 2140.Tn RAM . 2141.It Cd options MAXTSIZ=bytes 2142Sets the maximum size limit of a process' text segment. 2143See 2144.Pa /usr/include/machine/vmparam.h 2145for the port-specific default. 2146.It Cd options DFLDSIZ=bytes 2147Sets the default size limit of a process' data segment, the value that 2148will be returned as the soft limit for 2149.Dv RLIMIT_DATA 2150(as returned by 2151.Xr getrlimit 2 ) . 2152See 2153.Pa /usr/include/machine/vmparam.h 2154for the port-specific default. 2155.It Cd options MAXDSIZ=bytes 2156Sets the maximum size limit of a process' data segment, the value that 2157will be returned as the hard limit for 2158.Dv RLIMIT_DATA 2159(as returned by 2160.Xr getrlimit 2 ) . 2161See 2162.Pa /usr/include/machine/vmparam.h 2163for the port-specific default. 2164.It Cd options DFLSSIZ=bytes 2165Sets the default size limit of a process' stack segment, the value that 2166will be returned as the soft limit for 2167.Dv RLIMIT_STACK 2168(as returned by 2169.Xr getrlimit 2 ) . 2170See 2171.Pa /usr/include/machine/vmparam.h 2172for the port-specific default. 2173.It Cd options MAXSSIZ=bytes 2174Sets the maximum size limit of a process' stack segment, the value that 2175will be returned as the hard limit for 2176.Dv RLIMIT_STACK 2177(as returned by 2178.Xr getrlimit 2 ) . 2179See 2180.Pa /usr/include/machine/vmparam.h 2181for the port-specific default. 2182.It Cd options DUMP_ON_PANIC=integer 2183Defaults to one. 2184If set to zero, the kernel will not dump to the dump device when 2185it panics, though dumps can still be forced via 2186.Xr ddb 4 2187with the 2188.Dq sync 2189command. 2190Note that this sets the value of the 2191.Em kern.dump_on_panic 2192.Xr sysctl 3 2193variable which may be changed at run time -- see 2194.Xr sysctl 8 2195for details. 2196.It Cd options USE_TOPDOWN_VM 2197User space memory allocations (as made by 2198.Xr mmap 2 ) 2199will be arranged in a 2200.Dq top down 2201fashion instead of the traditional 2202.Dq upwards from MAXDSIZ \+ vm_daddr 2203method. 2204This includes the placement of 2205.Xr ld.so 1 . 2206Arranging memory in this manner allows either (or both of) the heap or 2207.Xr mmap 2 2208allocated space to grow larger than traditionally possible. 2209This option is not available on all ports, but is instead expected to be 2210offered on a port-by-port basis, after which some ports will commit to 2211using it by default. 2212See the files 2213.Pa /usr/include/uvm/uvm_param.h 2214for some implementation details, and 2215.Pa /usr/include/machine/vmparam.h 2216for port specific details including availability. 2217.It Cd options VMSWAP 2218Enable paging device/file support. 2219This option is on by default. 2220.It Cd options PDPOLICY_CLOCKPRO 2221Use CLOCK-Pro, an alternative page replace policy. 2222.El 2223.Ss Security Options 2224.Bl -ohang 2225.It Cd options INSECURE 2226Hardwires the kernel security level at \-1. 2227This means that the system 2228always runs in secure level \-1 mode, even when running multiuser. 2229See the manual page for 2230.Xr init 8 2231for details on the implications of this. 2232The kernel secure level may manipulated by the superuser by altering the 2233.Em kern.securelevel 2234.Xr sysctl 3 2235variable (the secure level may only be lowered by a call from process ID 1, 2236i.e., 2237.Xr init 8 ) . 2238See also 2239.Xr sysctl 8 2240and 2241.Xr sysctl 3 . 2242.It Cd options VERIFIED_EXEC_FP_MD5 2243Enables support for MD5 hashes in Veriexec. 2244.It Cd options VERIFIED_EXEC_FP_SHA1 2245Enables support for SHA1 hashes in Veriexec. 2246.It Cd options VERIFIED_EXEC_FP_RMD160 2247Enables support for RMD160 hashes in Veriexec. 2248.It Cd options VERIFIED_EXEC_FP_SHA256 2249Enables support for SHA256 hashes in Veriexec. 2250.It Cd options VERIFIED_EXEC_FP_SHA384 2251Enables support for SHA384 hashes in Veriexec. 2252.It Cd options VERIFIED_EXEC_FP_SHA512 2253Enables support for SHA512 hashes in Veriexec. 2254.It Cd options PAX_MPROTECT=value 2255Enables PaX MPROTECT, 2256.Xr mprotect 2 2257restrictions from the PaX project. 2258.Pp 2259The 2260.Ar value 2261is the default value for the 2262.Em global 2263knob, see 2264.Xr sysctl 3 . 2265If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2266using 2267.Xr paxctl 8 . 2268If 1, PaX MPROTECT will be enabled for all programs. 2269Programs can be exempted using 2270.Xr paxctl 8 . 2271.Pp 2272See 2273.Xr security 8 2274for more details. 2275.It Cd options PAX_SEGVGUARD=value 2276Enables PaX Segvguard. 2277.Pp 2278The 2279.Ar value 2280is the default value for the 2281.Em global 2282knob, see 2283.Xr sysctl 3 . 2284If 0, PaX Segvguard will be enabled only if explicitly set on programs 2285using 2286.Xr paxctl 8 . 2287If 1, PaX Segvguard will be enabled to all programs, and exemption can 2288be done using 2289.Xr paxctl 8 . 2290.Pp 2291See 2292.Xr security 8 2293for more details. 2294.It Cd options PAX_ASLR=value 2295Enables PaX ASLR. 2296.Pp 2297The 2298.Ar value 2299is the default value for the 2300.Em global 2301knob, see 2302.Xr sysctl 3 . 2303If 0, PaX ASLR will be enabled only if explicitly set on programs 2304using 2305.Xr paxctl 8 . 2306If 1, PaX ASLR will be enabled to all programs, and exemption can 2307be done using 2308.Xr paxctl 8 . 2309.Pp 2310See 2311.Xr security 8 2312for more details. 2313.El 2314.Ss amiga-specific Options 2315.Bl -ohang 2316.It Cd options BB060STUPIDROM 2317When the bootloader (which passes 2318.Tn AmigaOS 2319.Tn ROM 2320information) claims we have a 68060 2321.Tn CPU 2322without 2323.Tn FPU , 2324go look into the Processor Configuration Register (PCR) to find out. 2325You need this with 2326.Tn Amiga 2327.Tn ROM Ns s 2328up to (at least) V40.xxx (OS3.1), 2329when you boot via the bootblocks and don't have a DraCo. 2330.It Cd options IOBZCLOCK=frequency 2331The IOBlix boards come with two different serial master clocks: older ones 2332use 24 MHz, newer ones use 22.1184 MHz. 2333The driver normally assumes the latter. 2334If your board uses 24 MHz, you can recompile your kernel with 2335options IOBZCLOCK=24000000 2336or patch the kernel variable 2337.Tn iobzclock 2338to the same value. 2339.It Cd options LIMITMEM=value 2340If there, limit the part of the first memory bank used by 2341.Nx 2342to value megabytes. 2343Default is unlimited. 2344.It Cd options NKPTADD=addvalue 2345.It Cd options NKPTADDSHIFT=shiftvalue 2346The 2347.Tn CPU 2348specific 2349.Tn MMU 2350table for the kernel is pre-allocated at kernel startup time. 2351Part of it is scaled with 2352.Va maxproc , 2353to have enough room to hold the user program 2354.Tn MMU 2355tables; the second part is a fixed amount for the kernel itself. 2356.Pp 2357The third part accounts for the size of the file buffer cache. 2358Its size is either 2359.Dv NKPTADD 2360pages (if defined) or memory size in bytes divided by two to 2361the power of 2362.Dv NKPTADDSHIFT . 2363The default is undefined 2364.Dv NKPTADD 2365and 2366.Dv NKPTADDSHIFT=24 , 2367allowing for 16 buffers per megabyte of main memory (while 2368a GENERIC kernel allocates about half of that). 2369When you get "can't get KPT page" panics, you should increase 2370.Dv NKPTADD 2371(if defined), or decrease 2372.Dv NKPTADDSHIFT 2373by one. 2374.It Cd options P5PPC68KBOARD 2375Add special support for Phase5 mixed 68k+PPC boards. 2376Currently, this only affects rebooting from 2377.Nx 2378and is only needed on 68040+PPC, not on 237968060+PPC; without this, affected machines will hang after 2380.Nx 2381has shut 2382down and will only restart after a keyboard reset or a power cycle. 2383.El 2384.Ss arm32-specific Options 2385.Bl -ohang 2386.It Cd options FRENCH_KBD 2387Include translation for French keyboards when using 2388.Em pccons 2389on a Shark. 2390.It Cd options FINNISH_KBD 2391Include translation for Finnish keyboards when using 2392.Em pccons 2393on a Shark. 2394.It Cd options GERMAN_KBD 2395Include translation for German keyboards when using 2396.Em pccons 2397on a Shark. 2398.It Cd options NORWEGIAN_KBD 2399Include translation for French keyboards when using 2400.Em pccons 2401on a Shark. 2402.El 2403.Ss amd64-specific Options 2404.Bl -ohang 2405.It Cd options ENHANCED_SPEEDSTEP 2406Include support for the 2407.Tn Enhanced SpeedStep Technology 2408present in newer 2409.Tn CPU Ns s . 2410.It Cd options EST_FREQ_USERWRITE 2411Allow any user to change the frequency of an 2412.Tn Enhanced SpeedStep Technology 2413capable 2414.Tn CPU . 2415.It Cd options INTEL_ONDEMAND_CLOCKMOD 2416This enables the On Demand Clock Modulation by software 2417on Intel 2418.Tn CPUs 2419supporting the Thermal Monitor feature (TM). 2420You can select the duty cycle with 2421.Xr sysctl 8 2422in the node 2423.Em machdep.clockmod 2424if supported. 2425.It Cd options POWERNOW_K8 2426Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2427Technology, used to change the cpu voltage and frequency 2428on the fly. 2429.El 2430.Ss atari-specific Options 2431.Bl -ohang 2432.It Cd options DISKLABEL_AHDI 2433Include support for AHDI (native Atari) disklabels. 2434.It Cd options DISKLABEL_NBDA 2435Include support for 2436.Nx Ns Tn /atari 2437labels. 2438If you don't set this option, it will be set automatically. 2439.Nx Ns Tn /atari 2440will not work without it. 2441.It Cd options FALCON_SCSI 2442Include support for the 5380-SCSI configuration as found on the Falcon. 2443.It Cd options RELOC_KERNEL 2444If set, the kernel will relocate itself to TT-RAM, if possible. 2445This will give you a slightly faster system. 2446.Em Beware 2447that on some TT030 systems, 2448the system will frequently dump with MMU-faults with this option enabled. 2449.It Cd options SERCONSOLE 2450Allow the modem1-port to act as the system-console. 2451A carrier should be active on modem1 during system boot to active 2452the console functionality. 2453.It Cd options TT_SCSI 2454Include support for the 5380-SCSI configuration as found on the TT030 2455and Hades. 2456.El 2457.Ss i386-specific Options 2458.Bl -ohang 2459.It Cd options ENHANCED_SPEEDSTEP 2460Include support for the 2461.Tn Enhanced SpeedStep Technology 2462present in newer 2463.Tn CPU Ns s . 2464.It Cd options EST_FREQ_USERWRITE 2465Allow any user to change the frequency of an 2466.Tn Enhanced SpeedStep Technology 2467capable 2468.Tn CPU . 2469.It Cd options INTEL_ONDEMAND_CLOCKMOD 2470This enables the On Demand Clock Modulation by software 2471on Intel 2472.Tn CPUs 2473supporting the Thermal Monitor feature (TM). 2474You can select the duty cycle with 2475.Xr sysctl 8 2476in the node 2477.Em machdep.clockmod 2478if supported. 2479.It Cd options POWERNOW_K7 2480Include support for the AMD 2481.Tn PowerNow! Technology 2482present in AMD Athlon Mobile processors. 2483.It Cd options VIA_PADLOCK 2484Include support for the 2485.Tn AES 2486encryption instructions of the 2487.Tn VIA PadLock Security engine , 2488which is attached as a provider to the opencrypto framework. 2489.It Cd options CPURESET_DELAY=value 2490Specifies the time (in millisecond) to wait before doing a hardware reset 2491in the last phase of a reboot. 2492This gives the user a chance to see error messages from the shutdown 2493operations (like NFS unmounts, buffer cache flush, etc ...). 2494Setting this to 0 will disable the delay. 2495Default is 2 seconds. 2496.It Cd options VM86 2497Include support for virtual 8086 mode, used by 2498.Tn DOS 2499emulators and X servers to run BIOS code, e.g., for some VESA routines. 2500.It Cd options USER_LDT 2501Include i386-specific system calls for modifying the local descriptor table, 2502used by Windows emulators. 2503.It Cd options REALBASEMEM=integer 2504Overrides the base memory size passed in from the boot block. 2505(Value given in kilobytes.) 2506Use this option only if the boot block reports the size incorrectly. 2507(Note that some 2508.Tn BIOS Ns es 2509put the extended 2510.Tn BIOS 2511data area at the top of base memory, and therefore report a smaller 2512base memory size to prevent programs overwriting it. 2513This is correct behavior, and you should not use the 2514.Em REALBASEMEM 2515option to access this memory). 2516.It Cd options REALEXTMEM=integer 2517Overrides the extended memory size passed in from the boot block. 2518(Value given in kilobytes. 2519Extended memory does not include the first megabyte.) 2520Use this option only if the boot block reports the size incorrectly. 2521.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2522Select a non-US keyboard layout for the 2523.Em pccons 2524console driver. 2525.It Cd options CYRIX_CACHE_WORKS 2526Relevant only to the Cyrix 486DLC CPU. 2527This option is used to turn on the cache in hold-flush mode. 2528It is not turned on by default because it is known to have problems in 2529certain motherboard implementations. 2530.It Cd options CYRIX_CACHE_REALLY_WORKS 2531Relevant only to the Cyrix 486DLC CPU. 2532This option is used to turn on the cache in write-back mode. 2533It is not turned on by default because it is known to have problems in 2534certain motherboard implementations. 2535In order for this option to take effect, option 2536.Em CYRIX_CACHE_WORKS 2537must also be specified. 2538.It Cd options PCIBIOS 2539Enable support for initializing the 2540.Tn PCI 2541bus using information from the 2542.Tn BIOS . 2543See 2544.Xr pcibios 4 2545for details. 2546.It Cd options KSTACK_CHECK_DR0 2547Detect kernel stack overflow using DR0 register. 2548This option uses DR0 register exclusively so you can't use DR0 register for 2549other purpose (e.g., hardware breakpoint) if you turn this on. 2550.It Cd options MTRR 2551Include support for accessing MTRR registers from user-space. 2552See 2553.Xr i386_get_mtrr 2 . 2554.It Cd options BEEP_ONHALT 2555Make the system speaker emit several beeps when it is completely safe to 2556power down the computer after a 2557.Xr halt 8 2558command. 2559Requires 2560.Xr sysbeep 4 2561support. 2562.It Cd options BEEP_ONHALT_COUNT=times 2563Number of times to beep the speaker when 2564.Cd options BEEP_ONHALT 2565is enabled. 2566Defaults to 3. 2567.It Cd options BEEP_ONHALT_PITCH=hz 2568The tone frequency used when 2569.Cd options BEEP_ONHALT 2570option, in hertz. 2571Defaults to 1500. 2572.It Cd options BEEP_ONHALT_PERIOD=msecs 2573The duration of each beep when 2574.Cd options BEEP_ONHALT 2575is enabled, in milliseconds. 2576Defaults to 250. 2577.It Cd options MULTIBOOT 2578Makes the kernel Multiboot-compliant, allowing it to be booted through 2579a Multiboot-compliant boot manager such as GRUB. 2580See 2581.Xr multiboot 8 2582for more information. 2583.El 2584.Ss isa-specific Options 2585Options specific to 2586.Xr isa 4 2587busses. 2588.Bl -ohang 2589.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2590Control the section of IO bus space used for PCMCIA bus space mapping. 2591Ideally the probed defaults are satisfactory, however in practice 2592that is not always the case. 2593See 2594.Xr pcmcia 4 2595for details. 2596.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2597Controls the allowable interrupts that may be used for 2598.Tn PCMCIA 2599devices. 2600This mask is a logical-or of power-of-2s of allowable interrupts: 2601.Bd -literal -offset 04n 2602.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2603 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2604 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2605 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2606 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2607.Ed 2608.It Cd options PCKBC_CNATTACH_SELFTEST 2609Perform a self test of the keyboard controller before attaching it as a 2610console. 2611This might be necessary on machines where we boot on cold iron, and 2612pckbc refuses to talk until we request a self test. 2613Currently only the netwinder port uses it. 2614.It Cd options PCKBD_CNATTACH_MAY_FAIL 2615If this option is set the PS/2 keyboard will not be used as the console 2616if it cannot be found during boot. 2617This allows other keyboards, like USB, to be the console keyboard. 2618.It Cd options PCKBD_LAYOUT=layout 2619Sets the default keyboard layout, see 2620.Xr pckbd 4 . 2621.El 2622.Ss m68k-specific Options 2623.Bl -ohang 2624.It Cd options FPU_EMULATE 2625Include support for MC68881/MC68882 emulator. 2626.It Cd options FPSP 2627Include support for 68040 floating point. 2628.It Cd options M68020,M68030,M68040,M68060 2629Include support for a specific 2630.Tn CPU , 2631at least one (the one you are using) should be specified. 2632.It Cd options M060SP 2633Include software support for 68060. 2634This provides emulation of unimplemented 2635integer instructions as well as emulation of unimplemented floating point 2636instructions and data types and software support for floating point traps. 2637.El 2638.Ss powerpc-specific Options (OEA Only) 2639.Bl -ohang 2640.It Cd options PMAP_MEMLIMIT=value 2641Limit the amount of memory seen by the kernel to 2642.Ar value 2643bytes. 2644.It Cd options PTEGCOUNT=value 2645Specify the size of the page table as 2646.Ar value 2647PTE groups. 2648Normally, one PTEG is allocated per physical page frame. 2649.El 2650.Ss sparc-specific Options 2651.Bl -ohang 2652.It Cd options AUDIO_DEBUG 2653Enable simple event debugging of the logging of the 2654.Xr audio 4 2655device. 2656.It Cd options BLINK 2657Enable blinking of LED. 2658Blink rate is full cycle every N seconds for 2659N \*[Lt] then current load average. 2660See 2661.Xr getloadavg 3 . 2662.\" .It Cd options COLORFONT_CACHE 2663.\" What does this do? 2664.It Cd options COUNT_SW_LEFTOVERS 2665Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2666sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2667variables accessible from 2668.Xr ddb 4 . 2669See 2670.Xr sw 4 . 2671.It Cd options DEBUG_ALIGN 2672Adds debugging messages calls when user-requested alignment fault 2673handling happens. 2674.It Cd options DEBUG_EMUL 2675Adds debugging messages calls for emulated floating point and 2676alignment fixing operations. 2677.It Cd options DEBUG_SVR4 2678Prints registers messages calls for emulated SVR4 getcontext and 2679setcontext operations. 2680See 2681.Em options COMPAT_SVR4 . 2682.It Cd options EXTREME_DEBUG 2683Adds debugging functions callable from 2684.Xr ddb 4 . 2685The debug_pagetables, test_region and print_fe_map 2686functions print information about page tables for the SUN4M 2687platforms only. 2688.It Cd options EXTREME_EXTREME_DEBUG 2689Adds extra info to 2690.Em options EXTREME_DEBUG . 2691.It Cd options FPU_CONTEXT 2692Make 2693.Em options COMPAT_SVR4 2694getcontext and setcontext include floating point registers. 2695.It Cd options MAGMA_DEBUG 2696Adds debugging messages to the 2697.Xr magma 4 2698device. 2699.It Cd options RASTERCONS_FULLSCREEN 2700Use the entire screen for the console. 2701.It Cd options RASTERCONS_SMALLFONT 2702Use the Fixed font on the console, instead of the normal font. 2703.It Cd options SUN4 2704Support sun4 class machines. 2705.It Cd options SUN4C 2706Support sun4c class machines. 2707.It Cd options SUN4M 2708Support sun4m class machines. 2709.It Cd options SUN4_MMU3L 2710.\" XXX ??? 2711Enable support for sun4 3-level MMU machines. 2712.It Cd options V9 2713Enable SPARC V9 assembler in 2714.Xr ddb 4 . 2715.El 2716.Ss sparc64-specific Options 2717.Bl -ohang 2718.It Cd options AUDIO_DEBUG 2719Enable simple event debugging of the logging of the 2720.Xr audio 4 2721device. 2722.It Cd options BLINK 2723Enable blinking of LED. 2724Blink rate is full cycle every N seconds for 2725N \*[Lt] then current load average. 2726See 2727.Xr getloadavg 3 . 2728.El 2729.Ss x68k-specific Options 2730.Bl -ohang 2731.It Cd options EXTENDED_MEMORY 2732Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2733.It Cd options JUPITER 2734Include support for Jupiter-X MPU accelerator 2735.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2736Use the built-in serial port as the system-console. 2737Speed is specified in bps, defaults to 9600. 2738.It Cd options ITE_KERNEL_ATTR=value 2739Set the kernel message attribute for ITE. 2740Value, an integer, is a logical or of the following values: 2741.Bl -tag -width 4n -compact -offset indent 2742.It 1 2743color inversed 2744.It 2 2745underlined 2746.It 4 2747bolded 2748.El 2749.El 2750.\" The following requests should be uncommented and used where appropriate. 2751.\" .Sh FILES 2752.\" .Sh EXAMPLES 2753.Sh SEE ALSO 2754.Xr config 1 , 2755.Xr gdb 1 , 2756.Xr ktrace 1 , 2757.Xr pmc 1 , 2758.Xr quota 1 , 2759.Xr vndcompress 1 , 2760.Xr gettimeofday 2 , 2761.Xr i386_get_mtrr 2 , 2762.Xr i386_iopl 2 , 2763.Xr msgctl 2 , 2764.Xr msgget 2 , 2765.Xr msgrcv 2 , 2766.Xr msgsnd 2 , 2767.Xr ntp_adjtime 2 , 2768.Xr ntp_gettime 2 , 2769.Xr semctl 2 , 2770.Xr semget 2 , 2771.Xr semop 2 , 2772.Xr shmat 2 , 2773.Xr shmctl 2 , 2774.Xr shmdt 2 , 2775.Xr shmget 2 , 2776.Xr sysctl 3 , 2777.Xr apm 4 , 2778.Xr ddb 4 , 2779.Xr inet 4 , 2780.Xr iso 4 , 2781.Xr lkm 4 , 2782.Xr md 4 , 2783.Xr ns 4 , 2784.Xr pcibios 4 , 2785.Xr pcmcia 4 , 2786.Xr ppp 4 , 2787.Xr userconf 4 , 2788.Xr vnd 4 , 2789.Xr wscons 4 , 2790.Xr config 5 , 2791.Xr edquota 8 , 2792.Xr init 8 , 2793.Xr mdsetimage 8 , 2794.Xr mount_cd9660 8 , 2795.Xr mount_fdesc 8 , 2796.Xr mount_kernfs 8 , 2797.Xr mount_lfs 8 , 2798.Xr mount_mfs 8 , 2799.Xr mount_msdos 8 , 2800.Xr mount_nfs 8 , 2801.Xr mount_ntfs 8 , 2802.Xr mount_null 8 , 2803.Xr mount_portal 8 , 2804.Xr mount_procfs 8 , 2805.Xr mount_udf 8 , 2806.Xr mount_umap 8 , 2807.Xr mount_union 8 , 2808.Xr mrouted 8 , 2809.Xr newfs_lfs 8 , 2810.Xr ntpd 8 , 2811.Xr quotaon 8 , 2812.Xr rpc.rquotad 8 , 2813.Xr sysctl 8 , 2814.Xr in_getifa 9 2815.Sh HISTORY 2816The 2817.Nm 2818man page first appeared in 2819.Nx 1.3 . 2820.Sh BUGS 2821The 2822.Em EON 2823option should be a pseudo-device, and is also very fragile. 2824