1.\" $NetBSD: options.4,v 1.361 2008/03/22 12:29:01 jmmv 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 March 22, 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 MODULAR 1176Enables the new framework for kernel modules, which will eventually 1177replace LKMs. 1178This adds an in-kernel linker and loader, and requires userland support 1179to be useful. 1180See the 1181.Sy MKMODULAR 1182variable in 1183.Xr mk.conf 5 1184for more details. 1185.It Cd options VND_COMPRESSION 1186Enables the 1187.Xr vnd 4 1188driver to also handle compressed images. 1189See 1190.Xr vndcompress 1 , 1191.Xr vnd 4 1192and 1193.Xr vnconfig 8 1194for more information. 1195.It Cd options TFTPROOT 1196Download the root memory disk through TFTP at root mount time. 1197This enables the use of a root 1198.Tn RAM 1199disk without requiring it to be embedded in the kernel using 1200.Xr mdsetimage 8 . 1201The 1202.Tn RAM 1203disk name is obtained using DHCP's filename parameter. 1204This option requires 1205.Em MEMORY_DISK_HOOKS , 1206.Em MEMORY_DISK_DYNAMIC , 1207and 1208.Em MEMORY_DISK_IS_ROOT . 1209It is incompatible with 1210.Em MEMORY_DISK_ROOT_SIZE . 1211.It Cd options MALLOC_NOINLINE 1212Time critical fixed size memory allocation is performed with 1213.Fn MALLOC 1214and 1215.Fn FREE . 1216Normally these expand to inline code, but with 1217.Em MALLOC_NOINLINE 1218these call the normal 1219.Fn malloc 1220and 1221.Fn free 1222functions. 1223Useful for install media kernels, small memory systems and embedded systems. 1224.It Cd options HZ=integer 1225On ports that support it, set the system clock frequency (see 1226.Xr hz 9 ) 1227to the supplied value. 1228Handle with care. 1229.It Cd options NTP 1230Turns on in-kernel precision timekeeping support used by software 1231implementing 1232.Em NTP 1233(Network Time Protocol, RFC 1305). 1234The 1235.Em NTP 1236option adds an in-kernel Phase-Locked Loop (PLL) for normal 1237.Em NTP 1238operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1239operation. 1240.Xr ntpd 8 1241will employ a user-level PLL when kernel support is unavailable, 1242but the in-kernel version has lower latency and more precision, and 1243so typically keeps much better time. 1244The interface to the kernel 1245.Em NTP 1246support is provided by the 1247.Xr ntp_adjtime 2 1248and 1249.Xr ntp_gettime 2 1250system calls, which are intended for use by 1251.Xr ntpd 8 1252and are enabled by the option. 1253On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1254is not an integer, the 1255.Em NTP 1256option also enables extended-precision arithmetic to keep track of 1257fractional clock ticks at NTP time-format precision. 1258.It Cd options PPS_SYNC 1259This option enables a kernel serial line discipline for receiving time 1260phase signals from an external reference clock such as a radio clock. 1261(The 1262.Em NTP 1263option (which see) must be on if the 1264.Em PPS_SYNC 1265option is used.) 1266Some reference clocks generate a Pulse Per Second (PPS) signal in 1267phase with their time source. 1268The 1269.Em PPS 1270line discipline receives this signal on either the data leads 1271or the DCD control lead of a serial port. 1272.Em NTP 1273uses the PPS signal to discipline the local clock oscillator to a high 1274degree of precision (typically less than 50 microseconds in time and 12750.1 ppm in accuracy). 1276.Em PPS 1277can also generate a serial output pulse when the system receives a PPS 1278interrupt. 1279This can be used to measure the system interrupt latency and thus calibrate 1280.Em NTP 1281to account for it. 1282Using 1283.Em PPS 1284usually requires a 1285gadget box 1286to convert from TTL to RS-232 signal levels. 1287The gadget box and PPS are described in more detail in the HTML documentation 1288for 1289.Xr ntpd 8 1290in 1291.Pa /usr/share/doc/html/ntp . 1292.It Cd options NO_TSC_TIME 1293Don't use TSC microtime, even if available (i386 only). 1294Improves time behavior under VMware. 1295.It Cd options SETUIDSCRIPTS 1296Allows scripts with the setuid bit set to execute as the effective 1297user rather than the real user, just like binary executables. 1298.Pp 1299.Em NOTE : 1300Using this option will also enable 1301.Em options FDSCRIPTS 1302.It Cd options FDSCRIPTS 1303Allows execution of scripts with the execute bit set, but not the 1304read bit, by opening the file and passing the file descriptor to 1305the shell, rather than the filename. 1306.Pp 1307.Em NOTE : 1308Execute only (non-readable) scripts will have 1309.Va argv[0] 1310set to 1311.Pa /dev/fd/* . 1312What this option allows as far as security is 1313concerned, is the ability to safely ensure that the correct script 1314is run by the interpreter, as it is passed as an already open file. 1315.It Cd options PUCCN 1316Enables treating serial ports found on PCI boards 1317.Xr puc 4 1318as potential console devices. 1319The method for choosing such a console device is port dependent. 1320.It Cd options RTC_OFFSET=integer 1321The kernel (and typically the hardware battery backed-up clock on 1322those machines that have one) keeps time in 1323.Em UTC 1324(Universal Coordinated Time, once known as 1325.Em GMT , 1326or Greenwich Mean Time) 1327and not in the time of the local time zone. 1328The 1329.Em RTC_OFFSET 1330option is used on some ports (such as the i386) to tell the kernel 1331that the hardware clock is offset from 1332.Em UTC 1333by the specified number of minutes. 1334This is typically used when a machine boots several operating 1335systems and one of them wants the hardware clock to run in the 1336local time zone and not in 1337.Em UTC , 1338e.g. 1339.Em RTC_OFFSET=300 1340means 1341the hardware clock is set to US Eastern Time (300 minutes behind 1342.Em UTC ) , 1343and not 1344.Em UTC . 1345(Note: 1346.Em RTC_OFFSET 1347is used to initialize a kernel variable named 1348.Va rtc_offset 1349which is the source actually used to determine the clock offset, and 1350which may be accessed via the kern.rtc_offset sysctl variable. 1351See 1352.Xr sysctl 8 1353and 1354.Xr sysctl 3 1355for details. 1356Since the kernel clock is initialized from the hardware clock very 1357early in the boot process, it is not possible to meaningfully change 1358.Va rtc_offset 1359in system initialization scripts. 1360Changing this value currently may only be done at kernel compile 1361time or by patching the kernel and rebooting). 1362.Pp 1363.Em NOTE : 1364Unfortunately, in many cases where the hardware clock 1365is kept in local time, it is adjusted for Daylight Savings 1366Time; this means that attempting to use 1367.Em RTC_OFFSET 1368to let 1369.Nx 1370coexist with such an operating system, like Windows, 1371would necessitate changing 1372.Em RTC_OFFSET 1373twice a year. 1374As such, this solution is imperfect. 1375.It Cd options KMEMSTATS 1376The kernel memory allocator, 1377.Xr malloc 9 , 1378will keep statistics on its performance if this option is enabled. 1379Unfortunately, this option therefore essentially disables the 1380.Fn MALLOC 1381and 1382.Fn FREE 1383forms of the memory allocator, which are used to enhance the performance 1384of certain critical sections of code in the kernel. 1385This option therefore can lead to a significant decrease in the 1386performance of certain code in the kernel if enabled. 1387Examples of such code include the 1388.Fn namei 1389routine, the 1390.Xr ccd 4 1391driver, 1392and much of the networking code. 1393.It Cd options MAXUPRC=integer 1394Sets the soft 1395.Dv RLIMIT_NPROC 1396resource limit, which specifies the maximum number of simultaneous 1397processes a user is permitted to run, for process 0; 1398this value is inherited by its child processes. 1399It defaults to 1400.Em CHILD_MAX , 1401which is currently defined to be 160. 1402Setting 1403.Em MAXUPRC 1404to a value less than 1405.Em CHILD_MAX 1406is not permitted, as this would result in a violation of the semantics of 1407.St -p1003.1-90 . 1408.It Cd options NOFILE=integer 1409Sets the soft 1410.Dv RLIMIT_NOFILE 1411resource limit, which specifies the maximum number of open 1412file descriptors for each process; 1413this value is inherited by its child processes. 1414It defaults to 1415.Em OPEN_MAX , 1416which is currently defined to be 64. 1417.It Cd options MAXFILES=integer 1418Sets the default value of the 1419.Em kern.maxfiles 1420sysctl variable, which indicates the maximum number of files that may 1421be open in the system. 1422.It Cd options DEFCORENAME=string 1423Sets the default value of the 1424.Em kern.defcorename 1425sysctl variable, otherwise it is set to 1426.Nm %n.core . 1427See 1428.Xr sysctl 8 1429and 1430.Xr sysctl 3 1431for details. 1432.It Cd options RASOPS_CLIPPING 1433Enables clipping within the 1434.Nm rasops 1435raster-console output system. 1436.Em NOTE : 1437only available on architectures that use 1438.Nm rasops 1439for console output. 1440.It Cd options RASOPS_SMALL 1441Removes optimized character writing code from the 1442.Nm rasops 1443raster-console output system. 1444.Em NOTE : 1445only available on architectures that use 1446.Nm rasops 1447for console output. 1448.It Cd options INCLUDE_CONFIG_FILE 1449Embeds the kernel config file used to define the kernel in the kernel 1450binary itself. 1451The embedded data also includes any files directly included by the config 1452file itself, e.g. 1453.Pa GENERIC.local 1454or 1455.Pa std.$MACHINE . 1456The embedded config file can be extracted from the resulting kernel with 1457.Xr config 1 1458.Fl x , 1459or by the following command: 1460.Bd -literal -offset indent 1461strings netbsd | sed -n 's/^_CFG_//p' | unvis 1462.Ed 1463.It Cd options INCLUDE_JUST_CONFIG 1464Similar to the above option, but includes just the actual config file, 1465not any included files. 1466.It Cd options PIPE_SOCKETPAIR 1467Use slower, but smaller socketpair(2)-based pipe implementation instead 1468of default faster, but bigger one. 1469Primarily useful for installation kernels. 1470.It Cd options USERCONF 1471Compiles in the in-kernel device configuration manager. 1472See 1473.Xr userconf 4 1474for details. 1475.It Cd options PERFCTRS 1476Compiles in kernel support for CPU performance-monitoring counters. 1477See 1478.Xr pmc 1 1479for details. 1480.Em NOTE : 1481not available on all architectures. 1482.It Cd options SYSCALL_STATS 1483Count the number of times each system call number is called. 1484The values can be read through the sysctl interface and displayed using 1485.Xr systat 1 . 1486.Em NOTE : 1487not yet available on all architectures. 1488.It Cd options SYSCALL_TIMES 1489Count the time spent (using 1490.Fn cpu_counter32 ) 1491in each system call. 1492.Em NOTE : 1493Using this option will also enable 1494.Cd options SYSCALL_STATS . 1495.It Cd options SYSCALL_TIMES_HASCOUNTER 1496Force use of 1497.Fn cpu_counter32 1498even if 1499.Fn cpu_hascounter 1500reports false. 1501Useful for systems where the cycle counter doesn't run at a constant rate 1502(e.g. Soekris boxes). 1503.It Cd options XSERVER 1504Compiles in kernel support for 1505.Tn X11 1506on architectures that still use (or can use) the legacy 1507.Em pccons 1508console drivers rather than 1509.Xr wscons 4 . 1510These include bebox, i386, shark. 1511.It Cd options XSERVER_DDB 1512A supplement to XSERVER that adds support for entering 1513.Xr ddb 4 1514while in 1515.Tn X11 . 1516.It Cd options FILEASSOC 1517Support for 1518.Xr fileassoc 9 . 1519.It Cd options FILEASSOC_NHOOKS=integer 1520Number of storage slots per file for 1521.Xr fileassoc 9 . 1522Default is 4. 1523.El 1524.Ss Networking Options 1525.Bl -ohang 1526.It Cd options GATEWAY 1527Enables 1528.Em IPFORWARDING 1529(which see) 1530and (on most ports) increases the size of 1531.Em NMBCLUSTERS 1532(which see). 1533In general, 1534.Em GATEWAY 1535is used to indicate that a system should act as a router, and 1536.Em IPFORWARDING 1537is not invoked directly. 1538(Note that 1539.Em GATEWAY 1540has no impact on protocols other than 1541.Tn IP , 1542such as 1543.Tn CLNP 1544or 1545.Tn XNS ) . 1546.Em GATEWAY 1547option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1548.It Cd options ICMPPRINTFS 1549The 1550.Em ICMPPRINTFS 1551option will enable debugging information to be printed about 1552the 1553.Xr icmp 4 1554protocol. 1555.It Cd options IPFORWARDING=value 1556If 1557.Em value 1558is 1 this enables IP routing behavior. 1559If 1560.Em value 1561is 0 (the default), it disables it. 1562The 1563.Em GATEWAY 1564option sets this to 1 automatically. 1565With this option enabled, the machine will forward IP datagrams destined 1566for other machines between its interfaces. 1567Note that even without this option, the kernel will 1568still forward some packets (such as source routed packets) -- removing 1569.Em GATEWAY 1570and 1571.Em IPFORWARDING 1572is insufficient to stop all routing through a bastion host on a 1573firewall -- source routing is controlled independently. 1574To turn off source routing, use 1575.Em options IPFORWSRCRT=0 1576(which see). 1577Note that IP forwarding may be turned on and off independently of the 1578setting of the 1579.Em IPFORWARDING 1580option through the use of the 1581.Em net.inet.ip.forwarding 1582sysctl variable. 1583If 1584.Em net.inet.ip.forwarding 1585is 1, IP forwarding is on. 1586See 1587.Xr sysctl 8 1588and 1589.Xr sysctl 3 1590for details. 1591.It Cd options IPFORWSRCRT=value 1592If 1593.Em value 1594is set to zero, source routing of IP datagrams is turned off. 1595If 1596.Em value 1597is set to one (the default) or the option is absent, source routed IP 1598datagrams are forwarded by the machine. 1599Note that source routing of IP packets may be turned on and off 1600independently of the setting of the 1601.Em IPFORWSRCRT 1602option through the use of the 1603.Em net.inet.ip.forwsrcrt 1604sysctl variable. 1605If 1606.Em net.inet.ip.forwsrcrt 1607is 1, forwarding of source routed IP datagrams is on. 1608See 1609.Xr sysctl 8 1610and 1611.Xr sysctl 3 1612for details. 1613.It Cd options IFA_STATS 1614Tells the kernel to maintain per-address statistics on bytes sent 1615and received over (currently) Internet and AppleTalk addresses. 1616.\"This can be a fairly expensive operation, so you probably want to 1617.\"keep this disabled. 1618The option is not recommended as it degrades system stability. 1619.It Cd options IFQ_MAXLEN=value 1620Increases the allowed size of the network interface packet queues. 1621The default queue size is 50 packets, and you do not normally need 1622to increase it. 1623.It Cd options IPSELSRC 1624Includes support for source-address selection policies. 1625See 1626.Xr in_getifa 9 . 1627.It Cd options MROUTING 1628Includes support for IP multicast routers. 1629You certainly want 1630.Em INET 1631with this. 1632Multicast routing is controlled by the 1633.Xr mrouted 8 1634daemon. 1635See also option 1636.Cd PIM . 1637.It Cd options PIM 1638Includes support for Protocol Independent Multicast (PIM) routing. 1639You need 1640.Em MROUTING 1641and 1642.Em INET 1643with this. 1644Software using this can be found e.g. in 1645.Pa pkgsrc/net/xorp . 1646.It Cd options INET 1647Includes support for the 1648.Tn TCP/IP 1649protocol stack. 1650You almost certainly want this. 1651See 1652.Xr inet 4 1653for details. 1654.It Cd options INET6 1655Includes support for the 1656.Tn IPv6 1657protocol stack. 1658See 1659.Xr inet6 4 1660for details. 1661Unlike 1662.Em INET , 1663.Em INET6 1664enables multicast routing code as well. 1665This option requires 1666.Em INET 1667at this moment, but it should not. 1668.It Cd options ND6_DEBUG 1669The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1670for debugging IPv6 neighbor discovery protocol handling. 1671See 1672.Xr sysctl 3 1673for details. 1674.It Cd options IPSEC 1675Includes support for the 1676.Tn IPsec 1677protocol. 1678See 1679.Xr ipsec 4 1680for details. 1681.It Cd options IPSEC_DEBUG 1682Enables debugging code in 1683.Tn IPsec 1684stack. 1685See 1686.Xr ipsec 4 1687for details. 1688.It Cd options IPSEC_ESP 1689Includes support for 1690.Tn IPsec 1691.Tn ESP 1692protocol. 1693See 1694.Xr ipsec 4 1695for details. 1696.It Cd options IPSEC_NAT_T 1697Includes support for 1698.Tn IPsec 1699Network Address Translator traversal (NAT-T), as described in RFCs 3947 1700and 3948. 1701This feature might be patent-encumbered in some countries. 1702.It Cd options ALTQ 1703Enabled ALTQ (Alternate Queueing). 1704For simple rate-limiting, use 1705.Xr tbrconfig 8 1706to set up the interface transmission rate. 1707To use queueing disciplines, their appropriate kernel options should also 1708be defined (documented below). 1709Queueing disciplines are managed by 1710.Xr altqd 8 . 1711See 1712.Xr altq 9 1713for details. 1714.It Cd options ALTQ_HFSC 1715Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1716module. 1717HFSC supports both link-sharing and guaranteed real-time services. 1718HFSC employs a service curve based QoS model, and its unique feature 1719is an ability to decouple delay and bandwidth allocation. 1720Requires 1721.Em ALTQ_RED 1722to use the RED queueing discipline on HFSC classes, or 1723.Em ALTQ_RIO 1724to use the RIO queueing discipline on HFSC classes. 1725This option assumes 1726.Em ALTQ . 1727.It Cd options ALTQ_PRIQ 1728Include support for ALTQ-implemented PRIQ (Priority Queueing). 1729PRIQ implements a simple priority-based queueing discipline. 1730A higher priority class is always served first. 1731Requires 1732.Em ALTQ_RED 1733to use the RED queueing discipline on HFSC classes, or 1734.Em ALTQ_RIO 1735to use the RIO queueing discipline on HFSC classes. 1736This option assumes 1737.Em ALTQ . 1738.It Cd options ALTQ_WFQ 1739Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1740WFQ implements a weighted-round robin scheduler for a set of queues. 1741A weight can be assigned to each queue to give a different proportion 1742of the link capacity. 1743A hash function is used to map a flow to one of a set of queues. 1744This option assumes 1745.Em ALTQ . 1746.It Cd options ALTQ_FIFOQ 1747Include support for ALTQ-implemented FIFO queueing. 1748FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1749This option assumes 1750.Em ALTQ . 1751.It Cd options ALTQ_RIO 1752Include support for ALTQ-implemented RIO (RED with In/Out). 1753The original RIO has 2 sets of RED parameters; one for in-profile 1754packets and the other for out-of-profile packets. 1755At the ingress of the network, profile meters tag packets as IN or 1756OUT based on contracted profiles for customers. 1757Inside the network, IN packets receive preferential treatment by 1758the RIO dropper. 1759ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1760PHB of DiffServ (RFC 2597). 1761This option assumes 1762.Em ALTQ . 1763.It Cd options ALTQ_BLUE 1764Include support for ALTQ-implemented Blue buffer management. 1765Blue is another active buffer management mechanism. 1766This option assumes 1767.Em ALTQ . 1768.It Cd options ALTQ_FLOWVALVE 1769Include support for ALTQ-implemented Flowvalve. 1770Flowvalve is a simple implementation of a RED penalty box that identifies 1771and punishes misbehaving flows. 1772This option requires 1773.Em ALTQ_RED 1774and assumes 1775.Em ALTQ . 1776.It Cd options ALTQ_CDNR 1777Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1778packet marking/manipulation. 1779Traffic conditioners are components to meter, mark, or drop incoming 1780packets according to some rules. 1781As opposed to queueing disciplines, traffic conditioners handle incoming 1782packets at an input interface. 1783This option assumes 1784.Em ALTQ . 1785.It Cd options ALTQ_NOPCC 1786Disables use of processor cycle counter to measure time in ALTQ. 1787This option should be defined for a non-Pentium i386 CPU which does not 1788have TSC, SMP (per-CPU counters are not in sync), or power management 1789which affects processor cycle counter. 1790This option assumes 1791.Em ALTQ . 1792.It Cd options ALTQ_IPSEC 1793Include support for IPsec in IPv4 ALTQ. 1794This option assumes 1795.Em ALTQ . 1796.It Cd options ALTQ_JOBS 1797Include support for ALTQ-implemented JoBS (Joint Buffer Management 1798and Scheduling). 1799This option assumes 1800.Em ALTQ . 1801.It Cd options ALTQ_AFMAP 1802Include support for an undocumented ALTQ feature that is used to map an IP 1803flow to an ATM VC (Virtual Circuit). 1804This option assumes 1805.Em ALTQ . 1806.It Cd options ALTQ_LOCALQ 1807Include support for ALTQ-implemented local queues. 1808Its practical use is undefined. 1809Assumes 1810.Em ALTQ . 1811.It Cd options SUBNETSARELOCAL 1812Sets default value for net.inet.ip.subnetsarelocal variable, which 1813controls whether non-directly-connected subnets of connected networks 1814are considered "local" for purposes of choosing the MSS for a TCP 1815connection. 1816This is mostly present for historic reasons and completely irrelevant if 1817you enable Path MTU discovery. 1818.It Cd options HOSTZEROBROADCAST 1819Sets default value for net.inet.ip.hostzerobroadcast variable, which 1820controls whether the zeroth host address of each connected subnet is 1821also considered a broadcast address. 1822Default value is "1", for compatibility with old systems; if this is 1823set to zero on all hosts on a subnet, you should be able to fit an extra 1824host per subnet on the 1825".0" address. 1826.It Cd options MCLSHIFT=value 1827This option is the base-2 logarithm of the size of mbuf clusters. 1828The 1829.Bx 1830networking stack keeps network packets in a linked 1831list, or chain, of kernel buffer objects called mbufs. 1832The system provides larger mbuf clusters as an optimization for 1833large packets, instead of using long chains for large packets. 1834The mbuf cluster size, 1835or 1836.Em MCLBYTES , 1837must be a power of two, and is computed as two raised to the power 1838.Em MCLSHIFT . 1839On systems with Ethernet network adapters, 1840.Em MCLSHIFT 1841is often set to 11, giving 2048-byte mbuf clusters, large enough to 1842hold a 1500-byte 1843.Tn Ethernet 1844frame in a single cluster. 1845Systems with network interfaces supporting larger frame sizes like 1846.Tn ATM , 1847.Tn FDDI , 1848or 1849.Tn HIPPI 1850may perform better with 1851.Em MCLSHIFT 1852set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1853respectively. 1854.It Cd options NS 1855Include support for the 1856.Tn Xerox 1857.Tn XNS 1858protocol stack. 1859See 1860.Xr ns 4 1861for details. 1862.It Cd options ISO,TPIP 1863Include support for the ubiquitous 1864.Tn OSI 1865protocol stack. 1866See 1867.Xr iso 4 1868for details. 1869This option assumes 1870.Em INET . 1871.It Cd options EON 1872Include support for tunneling 1873.Tn OSI 1874protocols over 1875.Tn IP . 1876Known to be broken, or at least very fragile, and undocumented. 1877.It Cd options NETATALK 1878Include support for the 1879.Tn AppleTalk 1880protocol stack. 1881The kernel provides provision for the 1882.Em Datagram Delivery Protocol 1883(DDP), providing SOCK_DGRAM support and 1884.Tn AppleTalk 1885routing. 1886This stack is used by the 1887.Em NETATALK 1888package, which adds support for 1889.Tn AppleTalk 1890server services via user libraries and applications. 1891.It Cd options BLUETOOTH 1892Include support for the 1893.Tn Bluetooth 1894protocol stack. 1895See 1896.Xr bluetooth 4 1897for details. 1898.It Cd options IPNOPRIVPORTS 1899Normally, only root can bind a socket descriptor to a so-called 1900.Dq privileged 1901.Tn TCP 1902port, that is, a port number in the range 0-1023. 1903This option eliminates those checks from the kernel. 1904This can be useful if there is a desire to allow daemons without 1905privileges to bind those ports, e.g., on firewalls. 1906The security tradeoffs in doing this are subtle. 1907This option should only be used by experts. 1908.It Cd options TCP_COMPAT_42 1909.Tn TCP 1910bug compatibility with 1911.Bx 4.2 . 1912In 1913.Bx 4.2 , 1914.Tn TCP 1915sequence numbers were 32-bit signed values. 1916Modern implementations of TCP use unsigned values. 1917This option clamps the initial sequence number to start in 1918the range 2^31 rather than the full unsigned range of 2^32. 1919Also, under 1920.Bx 4.2 , 1921keepalive packets must contain at least one byte or else 1922the remote end would not respond. 1923.It Cd options TCP_DEBUG 1924Record the last 1925.Em TCP_NDEBUG 1926TCP packets with SO_DEBUG set, and decode to the console if 1927.Em tcpconsdebug 1928is set. 1929.It Cd options TCP_NDEBUG 1930Number of packets to record for 1931.Em TCP_DEBUG . 1932Defaults to 100. 1933.It Cd options TCP_SENDSPACE=value 1934.It Cd options TCP_RECVSPACE=value 1935These options set the max TCP window size to other sizes than the default. 1936The TCP window sizes can be altered via 1937.Xr sysctl 8 1938as well. 1939.It Cd options TCP_INIT_WIN=value 1940This option sets the initial TCP window size for non-local connections, 1941which is used when the transmission starts. 1942The default size is 1, but if the machine should act more aggressively, 1943the initial size can be set to some other value. 1944The initial TCP window size can be set via 1945.Xr sysctl 8 1946as well. 1947.It Cd options PFIL_HOOKS 1948This option turns on the packet filter interface hooks. 1949See 1950.Xr pfil 9 1951for details. 1952This option assumes 1953.Em INET . 1954.It Cd options IPFILTER_LOG 1955This option, in conjunction with 1956.Em pseudo-device ipfilter , 1957enables logging of IP packets using ip-filter. 1958.It Cd options IPFILTER_DEFAULT_BLOCK 1959This option sets the default policy of ip-filter. 1960If it is set, ip-filter will block packets by default. 1961.It Cd options BRIDGE_IPF 1962This option causes 1963.Em bridge 1964devices to use the IP and/or IPv6 filtering hooks, forming 1965a link-layer filter that uses protocol-layer rules. 1966This option assumes the presence of 1967.Em pseudo-device ipfilter . 1968.It Cd options MBUFTRACE 1969This option can help track down mbuf leaks. 1970When enabled, mbufs are tagged with the devices and protocols using them, 1971which slightly decreases network performance. 1972This additional information can be viewed with 1973.Xr netstat 1 : 1974.Dl Ic netstat Fl mssv 1975Not all devices or protocols support this option. 1976.El 1977.Ss Sysctl Related Options 1978.Bl -ohang 1979.It Cd options SYSCTL_DISALLOW_CREATE 1980Disallows the creation or deletion of nodes from the sysctl tree, as 1981well as the assigning of descriptions to nodes that lack them, by any 1982process. 1983These operations are still available to kernel sub-systems, including 1984loadable kernel modules. 1985.It Cd options SYSCTL_DISALLOW_KWRITE 1986Prevents processes from adding nodes to the sysctl tree that make 1987existing kernel memory areas writable. 1988Sections of kernel memory can still be read and new nodes that own 1989their own data may still be writable. 1990.It Cd options SYSCTL_DEBUG_SETUP 1991Causes the SYSCTL_SETUP routines to print a brief message when they 1992are invoked. 1993This is merely meant as an aid in determining the order in which 1994sections of the tree are created. 1995.It Cd options SYSCTL_DEBUG_CREATE 1996Prints a message each time 1997.Fn sysctl_create , 1998the function that adds nodes to the tree, is called. 1999.It Cd options SYSCTL_INCLUDE_DESCR 2000Causes the kernel to include short, human readable descriptions for 2001nodes in the sysctl tree. 2002The descriptions can be retrieved programmatically (see 2003.Xr sysctl 3 ) , 2004or by the sysctl binary itself (see 2005.Xr sysctl 8 ) . 2006The descriptions are meant to give an indication of the purpose and/or 2007effects of a given node's value, not replace the documentation for the 2008given subsystem as a whole. 2009.El 2010.Ss System V IPC Options 2011.Bl -ohang 2012.It Cd options SYSVMSG 2013Includes support for 2014.At V 2015style message queues. 2016See 2017.Xr msgctl 2 , 2018.Xr msgget 2 , 2019.Xr msgrcv 2 , 2020.Xr msgsnd 2 . 2021.It Cd options SYSVSEM 2022Includes support for 2023.At V 2024style semaphores. 2025See 2026.Xr semctl 2 , 2027.Xr semget 2 , 2028.Xr semop 2 . 2029.It Cd options SEMMNI=value 2030Sets the number of 2031.At V 2032style semaphore identifiers. 2033The GENERIC config file for your port will have the default. 2034.It Cd options SEMMNS=value 2035Sets the number of 2036.At V 2037style semaphores in the system. 2038The GENERIC config file for your port will have the default. 2039.It Cd options SEMUME=value 2040Sets the maximum number of undo entries per process for 2041.At V 2042style semaphores. 2043The GENERIC config file for your port will have the default. 2044.It Cd options SEMMNU=value 2045Sets the number of undo structures in the system for 2046.At V 2047style semaphores. 2048The GENERIC config file for your port will have the default. 2049.It Cd options SYSVSHM 2050Includes support for 2051.At V 2052style shared memory. 2053See 2054.Xr shmat 2 , 2055.Xr shmctl 2 , 2056.Xr shmdt 2 , 2057.Xr shmget 2 . 2058.It Cd options SHMMAXPGS=value 2059Sets the maximum number of 2060.At V 2061style shared memory pages that are available through the 2062.Xr shmget 2 2063system call. 2064Default value is 1024 on most ports. 2065See 2066.Pa /usr/include/machine/vmparam.h 2067for the default. 2068.El 2069.Ss VM Related Options 2070.Bl -ohang 2071.It Cd options NMBCLUSTERS=value 2072The number of mbuf clusters the kernel supports. 2073Mbuf clusters are MCLBYTES in size (usually 2k). 2074This is used to compute the size of the kernel VM map 2075.Em mb_map , 2076which maps mbuf clusters. 2077Default on most ports is 1024 (2048 with 2078.Dq options GATEWAY 2079). 2080See 2081.Pa /usr/include/machine/param.h 2082for exact default information. 2083Increase this value if you get 2084.Dq mclpool limit reached 2085messages. 2086.It Cd options NKMEMPAGES=value 2087.It Cd options NKMEMPAGES_MIN=value 2088.It Cd options NKMEMPAGES_MAX=value 2089Size of kernel VM map 2090.Em kmem_map , 2091in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2092from the 2093.Xr sysctl 8 2094variable 2095.Em hw.pagesize 2096). 2097This VM map is used to map the kernel malloc arena. 2098The kernel attempts to auto-size this map based on the amount of 2099physical memory in the system. 2100Platform-specific code may place bounds on this computed size, 2101which may be viewed with the 2102.Xr sysctl 8 2103variable 2104.Em vm.nkmempages . 2105See 2106.Pa /usr/include/machine/param.h 2107for the default upper and lower bounds. 2108The related options 2109.Sq NKMEMPAGES_MIN 2110and 2111.Sq NKMEMPAGES_MAX 2112allow the bounds to be overridden in the kernel configuration file. 2113These options are provided in the event the computed value is 2114insufficient resulting in an 2115.Dq out of space in kmem_map 2116panic. 2117.It Cd options SB_MAX=value 2118Sets the max size in bytes that a socket buffer is allowed to occupy. 2119The default is 256k, but sometimes it needs to be increased, for example 2120when using large TCP windows. 2121This option can be changed via 2122.Xr sysctl 8 2123as well. 2124.It Cd options SOMAXKVA=value 2125Sets the maximum size of kernel virtual memory that the socket buffers 2126are allowed to use. 2127The default is 16MB, but in situations where for example large TCP 2128windows are used this value must also be increased. 2129This option can be changed via 2130.Xr sysctl 8 2131as well. 2132.It Cd options BUFCACHE=value 2133Size of the buffer cache as a percentage of total available 2134.Tn RAM . 2135Ignored if BUFPAGES is also specified. 2136.It Cd options NBUF=value 2137Sets the number of buffer headers available, i.e., the number of 2138open files that may have a buffer cache entry. 2139Each buffer header 2140requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2141The default value is machine dependent, but is usually equal to the 2142value of BUFPAGES. 2143If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2144then NBUF may be reduced at run time so that the storage allocated 2145for buffer headers doesn't exceed that limit. 2146.It Cd options BUFPAGES=value 2147These options set the number of pages available for the buffer cache. 2148Their default value is a machine dependent value, often calculated as 2149between 5% and 10% of total available 2150.Tn RAM . 2151.It Cd options MAXTSIZ=bytes 2152Sets the maximum size limit of a process' text segment. 2153See 2154.Pa /usr/include/machine/vmparam.h 2155for the port-specific default. 2156.It Cd options DFLDSIZ=bytes 2157Sets the default size limit of a process' data segment, the value that 2158will be returned as the soft limit for 2159.Dv RLIMIT_DATA 2160(as returned by 2161.Xr getrlimit 2 ) . 2162See 2163.Pa /usr/include/machine/vmparam.h 2164for the port-specific default. 2165.It Cd options MAXDSIZ=bytes 2166Sets the maximum size limit of a process' data segment, the value that 2167will be returned as the hard limit for 2168.Dv RLIMIT_DATA 2169(as returned by 2170.Xr getrlimit 2 ) . 2171See 2172.Pa /usr/include/machine/vmparam.h 2173for the port-specific default. 2174.It Cd options DFLSSIZ=bytes 2175Sets the default size limit of a process' stack segment, the value that 2176will be returned as the soft limit for 2177.Dv RLIMIT_STACK 2178(as returned by 2179.Xr getrlimit 2 ) . 2180See 2181.Pa /usr/include/machine/vmparam.h 2182for the port-specific default. 2183.It Cd options MAXSSIZ=bytes 2184Sets the maximum size limit of a process' stack segment, the value that 2185will be returned as the hard limit for 2186.Dv RLIMIT_STACK 2187(as returned by 2188.Xr getrlimit 2 ) . 2189See 2190.Pa /usr/include/machine/vmparam.h 2191for the port-specific default. 2192.It Cd options DUMP_ON_PANIC=integer 2193Defaults to one. 2194If set to zero, the kernel will not dump to the dump device when 2195it panics, though dumps can still be forced via 2196.Xr ddb 4 2197with the 2198.Dq sync 2199command. 2200Note that this sets the value of the 2201.Em kern.dump_on_panic 2202.Xr sysctl 3 2203variable which may be changed at run time -- see 2204.Xr sysctl 8 2205for details. 2206.It Cd options USE_TOPDOWN_VM 2207User space memory allocations (as made by 2208.Xr mmap 2 ) 2209will be arranged in a 2210.Dq top down 2211fashion instead of the traditional 2212.Dq upwards from MAXDSIZ \+ vm_daddr 2213method. 2214This includes the placement of 2215.Xr ld.so 1 . 2216Arranging memory in this manner allows either (or both of) the heap or 2217.Xr mmap 2 2218allocated space to grow larger than traditionally possible. 2219This option is not available on all ports, but is instead expected to be 2220offered on a port-by-port basis, after which some ports will commit to 2221using it by default. 2222See the files 2223.Pa /usr/include/uvm/uvm_param.h 2224for some implementation details, and 2225.Pa /usr/include/machine/vmparam.h 2226for port specific details including availability. 2227.It Cd options VMSWAP 2228Enable paging device/file support. 2229This option is on by default. 2230.It Cd options PDPOLICY_CLOCKPRO 2231Use CLOCK-Pro, an alternative page replace policy. 2232.El 2233.Ss Security Options 2234.Bl -ohang 2235.It Cd options INSECURE 2236Hardwires the kernel security level at \-1. 2237This means that the system 2238always runs in secure level \-1 mode, even when running multiuser. 2239See the manual page for 2240.Xr init 8 2241for details on the implications of this. 2242The kernel secure level may manipulated by the superuser by altering the 2243.Em kern.securelevel 2244.Xr sysctl 3 2245variable (the secure level may only be lowered by a call from process ID 1, 2246i.e., 2247.Xr init 8 ) . 2248See also 2249.Xr sysctl 8 2250and 2251.Xr sysctl 3 . 2252.It Cd options VERIFIED_EXEC_FP_MD5 2253Enables support for MD5 hashes in Veriexec. 2254.It Cd options VERIFIED_EXEC_FP_SHA1 2255Enables support for SHA1 hashes in Veriexec. 2256.It Cd options VERIFIED_EXEC_FP_RMD160 2257Enables support for RMD160 hashes in Veriexec. 2258.It Cd options VERIFIED_EXEC_FP_SHA256 2259Enables support for SHA256 hashes in Veriexec. 2260.It Cd options VERIFIED_EXEC_FP_SHA384 2261Enables support for SHA384 hashes in Veriexec. 2262.It Cd options VERIFIED_EXEC_FP_SHA512 2263Enables support for SHA512 hashes in Veriexec. 2264.It Cd options PAX_MPROTECT=value 2265Enables PaX MPROTECT, 2266.Xr mprotect 2 2267restrictions from the PaX project. 2268.Pp 2269The 2270.Ar value 2271is the default value for the 2272.Em global 2273knob, see 2274.Xr sysctl 3 . 2275If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2276using 2277.Xr paxctl 8 . 2278If 1, PaX MPROTECT will be enabled for all programs. 2279Programs can be exempted using 2280.Xr paxctl 8 . 2281.Pp 2282See 2283.Xr security 8 2284for more details. 2285.It Cd options PAX_SEGVGUARD=value 2286Enables PaX Segvguard. 2287.Pp 2288The 2289.Ar value 2290is the default value for the 2291.Em global 2292knob, see 2293.Xr sysctl 3 . 2294If 0, PaX Segvguard will be enabled only if explicitly set on programs 2295using 2296.Xr paxctl 8 . 2297If 1, PaX Segvguard will be enabled to all programs, and exemption can 2298be done using 2299.Xr paxctl 8 . 2300.Pp 2301See 2302.Xr security 8 2303for more details. 2304.It Cd options PAX_ASLR=value 2305Enables PaX ASLR. 2306.Pp 2307The 2308.Ar value 2309is the default value for the 2310.Em global 2311knob, see 2312.Xr sysctl 3 . 2313If 0, PaX ASLR will be enabled only if explicitly set on programs 2314using 2315.Xr paxctl 8 . 2316If 1, PaX ASLR will be enabled to all programs, and exemption can 2317be done using 2318.Xr paxctl 8 . 2319.Pp 2320See 2321.Xr security 8 2322for more details. 2323.El 2324.Ss amiga-specific Options 2325.Bl -ohang 2326.It Cd options BB060STUPIDROM 2327When the bootloader (which passes 2328.Tn AmigaOS 2329.Tn ROM 2330information) claims we have a 68060 2331.Tn CPU 2332without 2333.Tn FPU , 2334go look into the Processor Configuration Register (PCR) to find out. 2335You need this with 2336.Tn Amiga 2337.Tn ROM Ns s 2338up to (at least) V40.xxx (OS3.1), 2339when you boot via the bootblocks and don't have a DraCo. 2340.It Cd options IOBZCLOCK=frequency 2341The IOBlix boards come with two different serial master clocks: older ones 2342use 24 MHz, newer ones use 22.1184 MHz. 2343The driver normally assumes the latter. 2344If your board uses 24 MHz, you can recompile your kernel with 2345options IOBZCLOCK=24000000 2346or patch the kernel variable 2347.Tn iobzclock 2348to the same value. 2349.It Cd options LIMITMEM=value 2350If there, limit the part of the first memory bank used by 2351.Nx 2352to value megabytes. 2353Default is unlimited. 2354.It Cd options NKPTADD=addvalue 2355.It Cd options NKPTADDSHIFT=shiftvalue 2356The 2357.Tn CPU 2358specific 2359.Tn MMU 2360table for the kernel is pre-allocated at kernel startup time. 2361Part of it is scaled with 2362.Va maxproc , 2363to have enough room to hold the user program 2364.Tn MMU 2365tables; the second part is a fixed amount for the kernel itself. 2366.Pp 2367The third part accounts for the size of the file buffer cache. 2368Its size is either 2369.Dv NKPTADD 2370pages (if defined) or memory size in bytes divided by two to 2371the power of 2372.Dv NKPTADDSHIFT . 2373The default is undefined 2374.Dv NKPTADD 2375and 2376.Dv NKPTADDSHIFT=24 , 2377allowing for 16 buffers per megabyte of main memory (while 2378a GENERIC kernel allocates about half of that). 2379When you get "can't get KPT page" panics, you should increase 2380.Dv NKPTADD 2381(if defined), or decrease 2382.Dv NKPTADDSHIFT 2383by one. 2384.It Cd options P5PPC68KBOARD 2385Add special support for Phase5 mixed 68k+PPC boards. 2386Currently, this only affects rebooting from 2387.Nx 2388and is only needed on 68040+PPC, not on 238968060+PPC; without this, affected machines will hang after 2390.Nx 2391has shut 2392down and will only restart after a keyboard reset or a power cycle. 2393.El 2394.Ss arm32-specific Options 2395.Bl -ohang 2396.It Cd options FRENCH_KBD 2397Include translation for French keyboards when using 2398.Em pccons 2399on a Shark. 2400.It Cd options FINNISH_KBD 2401Include translation for Finnish keyboards when using 2402.Em pccons 2403on a Shark. 2404.It Cd options GERMAN_KBD 2405Include translation for German keyboards when using 2406.Em pccons 2407on a Shark. 2408.It Cd options NORWEGIAN_KBD 2409Include translation for French keyboards when using 2410.Em pccons 2411on a Shark. 2412.El 2413.Ss amd64-specific Options 2414.Bl -ohang 2415.It Cd options ENHANCED_SPEEDSTEP 2416Include support for the 2417.Tn Enhanced SpeedStep Technology 2418present in newer 2419.Tn CPU Ns s . 2420.It Cd options EST_FREQ_USERWRITE 2421Allow any user to change the frequency of an 2422.Tn Enhanced SpeedStep Technology 2423capable 2424.Tn CPU . 2425.It Cd options INTEL_ONDEMAND_CLOCKMOD 2426This enables the On Demand Clock Modulation by software 2427on Intel 2428.Tn CPUs 2429supporting the Thermal Monitor feature (TM). 2430You can select the duty cycle with 2431.Xr sysctl 8 2432in the node 2433.Em machdep.clockmod 2434if supported. 2435.It Cd options POWERNOW_K8 2436Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2437Technology, used to change the cpu voltage and frequency 2438on the fly. 2439.El 2440.Ss atari-specific Options 2441.Bl -ohang 2442.It Cd options DISKLABEL_AHDI 2443Include support for AHDI (native Atari) disklabels. 2444.It Cd options DISKLABEL_NBDA 2445Include support for 2446.Nx Ns Tn /atari 2447labels. 2448If you don't set this option, it will be set automatically. 2449.Nx Ns Tn /atari 2450will not work without it. 2451.It Cd options FALCON_SCSI 2452Include support for the 5380-SCSI configuration as found on the Falcon. 2453.It Cd options RELOC_KERNEL 2454If set, the kernel will relocate itself to TT-RAM, if possible. 2455This will give you a slightly faster system. 2456.Em Beware 2457that on some TT030 systems, 2458the system will frequently dump with MMU-faults with this option enabled. 2459.It Cd options SERCONSOLE 2460Allow the modem1-port to act as the system-console. 2461A carrier should be active on modem1 during system boot to active 2462the console functionality. 2463.It Cd options TT_SCSI 2464Include support for the 5380-SCSI configuration as found on the TT030 2465and Hades. 2466.El 2467.Ss i386-specific Options 2468.Bl -ohang 2469.It Cd options ENHANCED_SPEEDSTEP 2470Include support for the 2471.Tn Enhanced SpeedStep Technology 2472present in newer 2473.Tn CPU Ns s . 2474.It Cd options EST_FREQ_USERWRITE 2475Allow any user to change the frequency of an 2476.Tn Enhanced SpeedStep Technology 2477capable 2478.Tn CPU . 2479.It Cd options INTEL_ONDEMAND_CLOCKMOD 2480This enables the On Demand Clock Modulation by software 2481on Intel 2482.Tn CPUs 2483supporting the Thermal Monitor feature (TM). 2484You can select the duty cycle with 2485.Xr sysctl 8 2486in the node 2487.Em machdep.clockmod 2488if supported. 2489.It Cd options POWERNOW_K7 2490Include support for the AMD 2491.Tn PowerNow! Technology 2492present in AMD Athlon Mobile processors. 2493.It Cd options VIA_PADLOCK 2494Include support for the 2495.Tn AES 2496encryption instructions of the 2497.Tn VIA PadLock Security engine , 2498which is attached as a provider to the opencrypto framework. 2499.It Cd options CPURESET_DELAY=value 2500Specifies the time (in millisecond) to wait before doing a hardware reset 2501in the last phase of a reboot. 2502This gives the user a chance to see error messages from the shutdown 2503operations (like NFS unmounts, buffer cache flush, etc ...). 2504Setting this to 0 will disable the delay. 2505Default is 2 seconds. 2506.It Cd options VM86 2507Include support for virtual 8086 mode, used by 2508.Tn DOS 2509emulators and X servers to run BIOS code, e.g., for some VESA routines. 2510.It Cd options USER_LDT 2511Include i386-specific system calls for modifying the local descriptor table, 2512used by Windows emulators. 2513.It Cd options REALBASEMEM=integer 2514Overrides the base memory size passed in from the boot block. 2515(Value given in kilobytes.) 2516Use this option only if the boot block reports the size incorrectly. 2517(Note that some 2518.Tn BIOS Ns es 2519put the extended 2520.Tn BIOS 2521data area at the top of base memory, and therefore report a smaller 2522base memory size to prevent programs overwriting it. 2523This is correct behavior, and you should not use the 2524.Em REALBASEMEM 2525option to access this memory). 2526.It Cd options REALEXTMEM=integer 2527Overrides the extended memory size passed in from the boot block. 2528(Value given in kilobytes. 2529Extended memory does not include the first megabyte.) 2530Use this option only if the boot block reports the size incorrectly. 2531.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2532Select a non-US keyboard layout for the 2533.Em pccons 2534console driver. 2535.It Cd options CYRIX_CACHE_WORKS 2536Relevant only to the Cyrix 486DLC CPU. 2537This option is used to turn on the cache in hold-flush mode. 2538It is not turned on by default because it is known to have problems in 2539certain motherboard implementations. 2540.It Cd options CYRIX_CACHE_REALLY_WORKS 2541Relevant only to the Cyrix 486DLC CPU. 2542This option is used to turn on the cache in write-back mode. 2543It is not turned on by default because it is known to have problems in 2544certain motherboard implementations. 2545In order for this option to take effect, option 2546.Em CYRIX_CACHE_WORKS 2547must also be specified. 2548.It Cd options PCIBIOS 2549Enable support for initializing the 2550.Tn PCI 2551bus using information from the 2552.Tn BIOS . 2553See 2554.Xr pcibios 4 2555for details. 2556.It Cd options KSTACK_CHECK_DR0 2557Detect kernel stack overflow using DR0 register. 2558This option uses DR0 register exclusively so you can't use DR0 register for 2559other purpose (e.g., hardware breakpoint) if you turn this on. 2560.It Cd options MTRR 2561Include support for accessing MTRR registers from user-space. 2562See 2563.Xr i386_get_mtrr 2 . 2564.It Cd options BEEP_ONHALT 2565Make the system speaker emit several beeps when it is completely safe to 2566power down the computer after a 2567.Xr halt 8 2568command. 2569Requires 2570.Xr sysbeep 4 2571support. 2572.It Cd options BEEP_ONHALT_COUNT=times 2573Number of times to beep the speaker when 2574.Cd options BEEP_ONHALT 2575is enabled. 2576Defaults to 3. 2577.It Cd options BEEP_ONHALT_PITCH=hz 2578The tone frequency used when 2579.Cd options BEEP_ONHALT 2580option, in hertz. 2581Defaults to 1500. 2582.It Cd options BEEP_ONHALT_PERIOD=msecs 2583The duration of each beep when 2584.Cd options BEEP_ONHALT 2585is enabled, in milliseconds. 2586Defaults to 250. 2587.It Cd options MULTIBOOT 2588Makes the kernel Multiboot-compliant, allowing it to be booted through 2589a Multiboot-compliant boot manager such as GRUB. 2590See 2591.Xr multiboot 8 2592for more information. 2593.El 2594.Ss isa-specific Options 2595Options specific to 2596.Xr isa 4 2597busses. 2598.Bl -ohang 2599.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2600Control the section of IO bus space used for PCMCIA bus space mapping. 2601Ideally the probed defaults are satisfactory, however in practice 2602that is not always the case. 2603See 2604.Xr pcmcia 4 2605for details. 2606.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2607Controls the allowable interrupts that may be used for 2608.Tn PCMCIA 2609devices. 2610This mask is a logical-or of power-of-2s of allowable interrupts: 2611.Bd -literal -offset 04n 2612.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2613 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2614 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2615 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2616 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2617.Ed 2618.It Cd options PCKBC_CNATTACH_SELFTEST 2619Perform a self test of the keyboard controller before attaching it as a 2620console. 2621This might be necessary on machines where we boot on cold iron, and 2622pckbc refuses to talk until we request a self test. 2623Currently only the netwinder port uses it. 2624.It Cd options PCKBD_CNATTACH_MAY_FAIL 2625If this option is set the PS/2 keyboard will not be used as the console 2626if it cannot be found during boot. 2627This allows other keyboards, like USB, to be the console keyboard. 2628.It Cd options PCKBD_LAYOUT=layout 2629Sets the default keyboard layout, see 2630.Xr pckbd 4 . 2631.El 2632.Ss m68k-specific Options 2633.Bl -ohang 2634.It Cd options FPU_EMULATE 2635Include support for MC68881/MC68882 emulator. 2636.It Cd options FPSP 2637Include support for 68040 floating point. 2638.It Cd options M68020,M68030,M68040,M68060 2639Include support for a specific 2640.Tn CPU , 2641at least one (the one you are using) should be specified. 2642.It Cd options M060SP 2643Include software support for 68060. 2644This provides emulation of unimplemented 2645integer instructions as well as emulation of unimplemented floating point 2646instructions and data types and software support for floating point traps. 2647.El 2648.Ss powerpc-specific Options (OEA Only) 2649.Bl -ohang 2650.It Cd options PMAP_MEMLIMIT=value 2651Limit the amount of memory seen by the kernel to 2652.Ar value 2653bytes. 2654.It Cd options PTEGCOUNT=value 2655Specify the size of the page table as 2656.Ar value 2657PTE groups. 2658Normally, one PTEG is allocated per physical page frame. 2659.El 2660.Ss sparc-specific Options 2661.Bl -ohang 2662.It Cd options AUDIO_DEBUG 2663Enable simple event debugging of the logging of the 2664.Xr audio 4 2665device. 2666.It Cd options BLINK 2667Enable blinking of LED. 2668Blink rate is full cycle every N seconds for 2669N \*[Lt] then current load average. 2670See 2671.Xr getloadavg 3 . 2672.\" .It Cd options COLORFONT_CACHE 2673.\" What does this do? 2674.It Cd options COUNT_SW_LEFTOVERS 2675Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2676sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2677variables accessible from 2678.Xr ddb 4 . 2679See 2680.Xr sw 4 . 2681.It Cd options DEBUG_ALIGN 2682Adds debugging messages calls when user-requested alignment fault 2683handling happens. 2684.It Cd options DEBUG_EMUL 2685Adds debugging messages calls for emulated floating point and 2686alignment fixing operations. 2687.It Cd options DEBUG_SVR4 2688Prints registers messages calls for emulated SVR4 getcontext and 2689setcontext operations. 2690See 2691.Em options COMPAT_SVR4 . 2692.It Cd options EXTREME_DEBUG 2693Adds debugging functions callable from 2694.Xr ddb 4 . 2695The debug_pagetables, test_region and print_fe_map 2696functions print information about page tables for the SUN4M 2697platforms only. 2698.It Cd options EXTREME_EXTREME_DEBUG 2699Adds extra info to 2700.Em options EXTREME_DEBUG . 2701.It Cd options FPU_CONTEXT 2702Make 2703.Em options COMPAT_SVR4 2704getcontext and setcontext include floating point registers. 2705.It Cd options MAGMA_DEBUG 2706Adds debugging messages to the 2707.Xr magma 4 2708device. 2709.It Cd options RASTERCONS_FULLSCREEN 2710Use the entire screen for the console. 2711.It Cd options RASTERCONS_SMALLFONT 2712Use the Fixed font on the console, instead of the normal font. 2713.It Cd options SUN4 2714Support sun4 class machines. 2715.It Cd options SUN4C 2716Support sun4c class machines. 2717.It Cd options SUN4M 2718Support sun4m class machines. 2719.It Cd options SUN4_MMU3L 2720.\" XXX ??? 2721Enable support for sun4 3-level MMU machines. 2722.It Cd options V9 2723Enable SPARC V9 assembler in 2724.Xr ddb 4 . 2725.El 2726.Ss sparc64-specific Options 2727.Bl -ohang 2728.It Cd options AUDIO_DEBUG 2729Enable simple event debugging of the logging of the 2730.Xr audio 4 2731device. 2732.It Cd options BLINK 2733Enable blinking of LED. 2734Blink rate is full cycle every N seconds for 2735N \*[Lt] then current load average. 2736See 2737.Xr getloadavg 3 . 2738.El 2739.Ss x68k-specific Options 2740.Bl -ohang 2741.It Cd options EXTENDED_MEMORY 2742Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2743.It Cd options JUPITER 2744Include support for Jupiter-X MPU accelerator 2745.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2746Use the built-in serial port as the system-console. 2747Speed is specified in bps, defaults to 9600. 2748.It Cd options ITE_KERNEL_ATTR=value 2749Set the kernel message attribute for ITE. 2750Value, an integer, is a logical or of the following values: 2751.Bl -tag -width 4n -compact -offset indent 2752.It 1 2753color inversed 2754.It 2 2755underlined 2756.It 4 2757bolded 2758.El 2759.El 2760.\" The following requests should be uncommented and used where appropriate. 2761.\" .Sh FILES 2762.\" .Sh EXAMPLES 2763.Sh SEE ALSO 2764.Xr config 1 , 2765.Xr gdb 1 , 2766.Xr ktrace 1 , 2767.Xr pmc 1 , 2768.Xr quota 1 , 2769.Xr vndcompress 1 , 2770.Xr gettimeofday 2 , 2771.Xr i386_get_mtrr 2 , 2772.Xr i386_iopl 2 , 2773.Xr msgctl 2 , 2774.Xr msgget 2 , 2775.Xr msgrcv 2 , 2776.Xr msgsnd 2 , 2777.Xr ntp_adjtime 2 , 2778.Xr ntp_gettime 2 , 2779.Xr semctl 2 , 2780.Xr semget 2 , 2781.Xr semop 2 , 2782.Xr shmat 2 , 2783.Xr shmctl 2 , 2784.Xr shmdt 2 , 2785.Xr shmget 2 , 2786.Xr sysctl 3 , 2787.Xr apm 4 , 2788.Xr ddb 4 , 2789.Xr inet 4 , 2790.Xr iso 4 , 2791.Xr lkm 4 , 2792.Xr md 4 , 2793.Xr ns 4 , 2794.Xr pcibios 4 , 2795.Xr pcmcia 4 , 2796.Xr ppp 4 , 2797.Xr userconf 4 , 2798.Xr vnd 4 , 2799.Xr wscons 4 , 2800.Xr config 5 , 2801.Xr edquota 8 , 2802.Xr init 8 , 2803.Xr mdsetimage 8 , 2804.Xr mount_cd9660 8 , 2805.Xr mount_fdesc 8 , 2806.Xr mount_kernfs 8 , 2807.Xr mount_lfs 8 , 2808.Xr mount_mfs 8 , 2809.Xr mount_msdos 8 , 2810.Xr mount_nfs 8 , 2811.Xr mount_ntfs 8 , 2812.Xr mount_null 8 , 2813.Xr mount_portal 8 , 2814.Xr mount_procfs 8 , 2815.Xr mount_udf 8 , 2816.Xr mount_umap 8 , 2817.Xr mount_union 8 , 2818.Xr mrouted 8 , 2819.Xr newfs_lfs 8 , 2820.Xr ntpd 8 , 2821.Xr quotaon 8 , 2822.Xr rpc.rquotad 8 , 2823.Xr sysctl 8 , 2824.Xr in_getifa 9 2825.Sh HISTORY 2826The 2827.Nm 2828man page first appeared in 2829.Nx 1.3 . 2830.Sh BUGS 2831The 2832.Em EON 2833option should be a pseudo-device, and is also very fragile. 2834