1.\" $NetBSD: options.4,v 1.353 2007/09/22 19:47:51 martin 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 June 3, 2007 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 disklabel 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 currenty on by default and enables the pty multiplexor 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_HPUX 439On those architectures that support it, this enables binary 440compatibility with 441.Tn HP/UX 442applications built for the same architecture. 443This is limited to the hp300 port, and has some known bugs. 444A limited set of programs do work. 445.It Cd options COMPAT_IBCS2 446On those architectures that support it, this enables binary 447compatibility with iBCS2 or SVR3 applications built for the same architecture. 448This is currently limited to the i386 and vax ports. 449.It Cd options COMPAT_IRIX 450On those architectures that support it, this enables binary 451compatibility with IRIX o32 binaries built for the same architecture. 452This feature is experimental, and it is currently limited to 453the sgimips port. 454.It Cd options COMPAT_MACH 455On those architectures that support it, this enables the emulation of 456Mach kernel traps for binaries built for the same architecture. 457This feature is highly experimental and it is currently 458limited to the i386 and powerpc ports of 459.Nx . 460.It Cd options COMPAT_OSF1 461On those architectures that support it, this enables binary 462compatibility with 463.Tn Digital 464.Ux 465.Po 466formerly 467.Tn OSF/1 468.Pc 469applications built for the same architecture. 470This is currently limited to the alpha port. 471.It Cd options COMPAT_NOMID 472Enable compatibility with 473.Xr a.out 5 474executables that lack a machine ID. 475This includes 476.Nx 0.8 Ns 's 477ZMAGIC format, and 386BSD and BSDI's 478QMAGIC, NMAGIC, and OMAGIC 479.Xr a.out 5 480formats. 481.It Cd options COMPAT_NETBSD32 482On those architectures that support it, this enables binary 483compatibility with 32-bit applications built for the same architecture. 484This is currently limited to the amd64 and sparc64 ports, and only 485applicable for 64-bit kernels. 486.It Cd options COMPAT_SVR4_32 487On those architectures that support it, this enables binary 488compatibility with 32-bit SVR4 applications built for the same architecture. 489This is currently limited to the sparc64 port, and only applicable for 49064-bit kernels. 491.It Cd options COMPAT_AOUT_M68K 492On m68k architectures which have switched to ELF, 493this enables binary compatibility with 494.Nx Ns Tn /m68k 495.Xr a.out 5 496executables on 497.Nx Ns Tn /m68k 498ELF kernels. 499This handles alignment incompatibility of m68k ABI between 500a.out and ELF which causes the structure padding differences. 501Currently only some system calls which use 502.Va struct stat 503are adjusted and some binaries which use 504.Xr sysctl 3 505to retrieve network details would not work properly. 506.It Cd options EXEC_MACHO 507On those architectures that support it, this adds support for running 508Mach-O executables. 509This is currently limited to the i386 and powerpc ports of 510.Nx . 511.It Cd options EXEC_ELF_NOTELESS 512Run unidentified ELF binaries as 513.Nx 514binaries. 515This might be needed for very old 516.Nx 517ELF binaries on some archs. 518These old binaries didn't contain an appropriate 519.Li .note.netbsd.ident 520section, and thus can't be identified by the kernel as 521.Nx 522binaries otherwise. 523Beware - if this option is on, the kernel would run 524.Em any 525unknown ELF binaries as if they were 526.Nx 527binaries. 528.It Cd options P1003_1B_SEMAPHORE 529Includes kernel support for the standard C library 530.Pq libc 531functions that implement semaphores as specified in 532.St -p1003.1-96 . 533.El 534.Ss Debugging Options 535.Bl -ohang 536.It Cd options DDB 537Compiles in a kernel debugger for diagnosing kernel problems. 538See 539.Xr ddb 4 540for details. 541.Em NOTE : 542not available on all architectures. 543.It Cd options DDB_FROMCONSOLE=integer 544If set to non-zero, DDB may be entered by sending a break on a serial 545console or by a special key sequence on a graphics console. 546A value of "0" ignores console breaks or key sequences. 547If not explicitly specified, the default value is "1". 548Note that this sets the value of the 549.Em ddb.fromconsole 550.Xr sysctl 3 551variable which may be changed at run time -- see 552.Xr sysctl 8 553for details. 554.It Cd options DDB_HISTORY_SIZE=integer 555If this is non-zero, enable history editing in the kernel debugger 556and set the size of the history to this value. 557.It Cd options DDB_ONPANIC 558The default if not specified is 559.Dq 1 560- just enter into DDB. 561If set to 562.Dq 2 563the kernel will 564attempt to print out a stack trace before entering into DDB. 565If set to 566.Dq 0 567the kernel will attempt to print out a stack trace 568and reboot the system. 569If set to 570.Dq -1 571then neither a stack trace is printed or DDB entered - 572it is as if DDB were not compiled into the kernel. 573Note that this sets the value of the 574.Em ddb.onpanic 575.Xr sysctl 3 576variable which may be changed at run time -- see 577.Xr sysctl 8 578for details. 579.It Cd options DDB_COMMANDONENTER=string 580This option specify commands which will be executed on each entry to DDB. 581This sets the default value of the 582.Em ddb.commandonenter 583.Xr sysctl 3 584variable which may be changed at run time. 585.It Cd options DDB_BREAK_CHAR=integer 586This option overrides using break to enter the kernel debugger 587on the serial console. 588The value given is the ascii value to be used instead. 589This is currently only supported by the com driver. 590.It Cd options DDB_VERBOSE_HELP 591This option adds more verbose descriptions to the 592.Em help 593command. 594.It Cd options KGDB 595Compiles in a remote kernel debugger stub for diagnosing kernel problems 596using the 597.Dq remote target 598feature of gdb. 599See 600.Xr gdb 1 601for details. 602.Em NOTE : 603not available on all architectures. 604.It Cd options KGDB_DEV 605Device number 606.Po 607as a 608.Dv dev_t 609.Pc 610of kgdb device. 611.It Cd options KGDB_DEVADDR 612Memory address of kgdb device. 613.It Cd options KGDB_DEVMODE 614Permissions of kgdb device. 615.It Cd options KGDB_DEVNAME 616Device name of kgdb device. 617.It Cd options KGDB_DEVRATE 618Baud rate of kgdb device. 619.It Cd makeoptions DEBUG="-g" 620The 621.Fl g 622flag causes 623.Pa netbsd.gdb 624to be built in addition to 625.Pa netbsd . 626.Pa netbsd.gdb 627is useful for debugging kernel crash dumps with gdb. 628See 629.Xr gdb 1 630for details. 631This also turns on 632.Em options DEBUG 633(which see). 634.It Cd options DEBUG 635Turns on miscellaneous kernel debugging. 636Since options are turned into preprocessor defines (see above), 637.Em options DEBUG 638is equivalent to doing a 639.Em #define DEBUG 640throughout the kernel. 641Much of the kernel has 642.Em #ifdef DEBUG 643conditionalized debugging code. 644Note that many parts of the kernel (typically device drivers) include their own 645.Em #ifdef XXX_DEBUG 646conditionals instead. 647This option also turns on certain other options, 648which may decrease system performance. 649.It Cd options DIAGNOSTIC 650Adds code to the kernel that does internal consistency checks. 651This code will cause the kernel to panic if corruption of internal data 652structures is detected. 653These checks can decrease performance up to 15%. 654.It Cd options KSTACK_CHECK_MAGIC 655Check kernel stack usage and panic if stack overflow is detected. 656This check is performance sensitive because it scans stack on each context 657switch. 658.It Cd options KTRACE 659Add hooks for the system call tracing facility, which allows users to 660watch the system call invocation behavior of processes. 661See 662.Xr ktrace 1 663for details. 664.It Cd options MSGBUFSIZE=integer 665This option sets the size of the kernel message buffer. 666This buffer holds the kernel output of 667.Fn printf 668when not (yet) read by 669.Xr syslogd 8 . 670This is particularly useful when the system has crashed and you wish to lookup 671the kernel output from just before the crash. 672Also, since the autoconfig output becomes more and more verbose, 673it sometimes happens that the message buffer overflows before 674.Xr syslogd 8 675was able to read it. 676Note that not all systems are capable of obtaining a variable sized message 677buffer. 678There are also some systems on which memory contents are not preserved 679across reboots. 680.It Cd options MALLOCLOG 681Enables an event log for 682.Xr malloc 9 . 683Useful for tracking down 684.Dq Data modified on freelist 685and 686.Dq multiple free 687problems. 688.It Cd options MALLOCLOGSIZE=integer 689Defines the number of entries in the malloc log. 690Default is 100000 entries. 691.It Cd options SYSTRACE 692Add hooks for the system call policy facility. 693See 694.Xr systrace 1 695for details. 696.It Cd options UVMHIST 697Enables the UVM history logs, which create in-memory traces of 698various UVM activities. 699These logs can be displayed be calling 700.Fn uvmhist_dump 701or 702.Fn uvm_hist 703with appropriate arguments from DDB. 704See the kernel source file sys/uvm/uvm_stat.c for details. 705.It Cd options UVMHIST_PRINT 706Prints the UVM history logs on the system console as entries are added. 707Note that the output is 708.Em extremely 709voluminous, so this option is really only useful for debugging 710the very earliest parts of kernel initialization. 711.El 712.Ss File Systems 713.Bl -ohang 714.It Cd file-system FFS 715Includes code implementing the Berkeley Fast File System 716.Em ( FFS ) . 717Most machines need this if they are not running diskless. 718.It Cd file-system EXT2FS 719Includes code implementing the Second Extended File System 720.Em ( EXT2FS ) , 721revision 0 and revision 1 with the 722.Em filetype 723and 724.Em sparse_super 725options. 726This is the most commonly used file system on the Linux operating system, 727and is provided here for compatibility. 728Some of the specific features of 729.Em EXT2FS 730like the "behavior on errors" are not implemented. 731This file system can't be used with UID or GID greater than 65535. 732See 733.Xr mount_ext2fs 8 734for details. 735.It Cd file-system LFS 736.Bq Em EXPERIMENTAL 737Include the Log-structured File System 738.Em ( LFS ) . 739See 740.Xr mount_lfs 8 741and 742.Xr newfs_lfs 8 743for details. 744.It Cd file-system MFS 745Include the Memory File System 746.Em ( MFS ) . 747This file system stores files in swappable memory, and produces 748notable performance improvements when it is used as the file store 749for 750.Pa /tmp 751and similar file systems. 752See 753.Xr mount_mfs 8 754for details. 755.It Cd file-system NFS 756Include the client side of the Network File System 757.Pq Tn NFS 758remote file sharing protocol. 759Although the bulk of the code implementing 760.Tn NFS 761is kernel based, several user level daemons are needed for it to work. 762See 763.Xr mount_nfs 8 764for details. 765.It Cd file-system CD9660 766Includes code for the 767.Tn ISO 7689660 + Rock Ridge file system, which is the standard file system on many 769.Tn CD-ROM 770discs. 771Useful primarily if you have a 772.Tn CD-ROM 773drive. 774See 775.Xr mount_cd9660 8 776for details. 777.It Cd file-system MSDOSFS 778Includes the 779.Tn MS-DOS 780FAT file system, which is reportedly still used 781by unfortunate people who have not heard about 782.Nx . 783Also implements the 784.Tn Windows 95 785extensions to the same, which permit the use of longer, mixed case 786file names. 787See 788.Xr mount_msdos 8 789and 790.Xr fsck_msdos 8 791for details. 792.It Cd file-system NTFS 793.Bq Em EXPERIMENTAL 794Includes code for the 795.Tn Microsoft Windows NT 796file system. 797See 798.Xr mount_ntfs 8 799for details. 800.It Cd file-system FDESC 801Includes code for a file system, conventionally mounted on 802.Pa /dev/fd , 803which permits access to the per-process file descriptor space via 804special files in the file system. 805See 806.Xr mount_fdesc 8 807for details. 808Note that this facility is redundant, and thus unneeded on most 809.Nx 810systems, since the 811.Xr fd 4 812pseudo-device driver already provides identical functionality. 813On most 814.Nx 815systems, instances of 816.Xr fd 4 817are mknoded under 818.Pa /dev/fd/ 819and on 820.Pa /dev/stdin , 821.Pa /dev/stdout , 822and 823.Pa /dev/stderr . 824.It Cd file-system KERNFS 825Includes code which permits the mounting of a special file system 826(normally mounted on 827.Pa /kern ) 828in which files representing various kernel variables and parameters 829may be found. 830See 831.Xr mount_kernfs 8 832for details. 833.It Cd file-system NULLFS 834Includes code for a loopback file system. 835This permits portions of the file hierarchy to be re-mounted in other places. 836The code really exists to provide an example of a stackable file system layer. 837See 838.Xr mount_null 8 839for details. 840.It Cd file-system OVERLAY 841Includes code for a file system filter. 842This permits the overlay file system to intercept all access to an underlying 843file system. 844This file system is intended to serve as an example of a stacking file 845system which has a need to interpose itself between an underlying file 846system and all other access. 847See 848.Xr mount_overlay 8 849for details. 850.It Cd file-system PORTAL 851.Bq Em EXPERIMENTAL 852Includes the portal file system. 853This permits interesting tricks like opening 854.Tn TCP 855sockets by opening files in the file system. 856The portal file system is conventionally mounted on 857.Pa /p 858and is partially implemented by a special daemon. 859See 860.Xr mount_portal 8 861for details. 862.It Cd file-system PROCFS 863Includes code for a special file system (conventionally mounted on 864.Pa /proc ) 865in which the process space becomes visible in the file system. 866Among 867other things, the memory spaces of processes running on the system are 868visible as files, and signals may be sent to processes by writing to 869.Pa ctl 870files in the procfs namespace. 871See 872.Xr mount_procfs 8 873for details. 874.It Cd file-system UDF 875.Bq Em EXPERIMENTAL 876Includes code for the UDF file system commonly found on CD and DVD 877media but also more and more on USB sticks. 878Useful primarily if you have a CD or a DVD drive, be it a read-only 879or a rewritable device. 880Currently only supports read-access. 881See 882.Xr mount_udf 8 883for details. 884.It Cd file-system UMAPFS 885Includes a loopback file system in which user and group IDs may be 886remapped -- this can be useful when mounting alien file systems with 887different UIDs and GIDs than the local system. 888See 889.Xr mount_umap 8 890for details. 891.It Cd file-system UNION 892.Bq Em EXPERIMENTAL 893Includes code for the union file system, which permits directories to 894be mounted on top of each other in such a way that both file systems 895remain visible -- this permits tricks like allowing writing (and the 896deleting of files) on a read-only file system like a 897.Tn CD-ROM 898by mounting a local writable file system on top of the read-only file system. 899See 900.Xr mount_union 8 901for details. 902.It Cd file-system CODA 903.Bq Em EXPERIMENTAL 904Includes code for the Coda file system. 905Coda is a distributed file system like NFS and AFS. 906It is freely available, like NFS, but it functions much like AFS in being a 907.Dq stateful 908file system. 909Both Coda and AFS cache files on your local machine to improve performance. 910Then Coda goes a step further than AFS by letting you access the cached 911files when there is no available network, viz. disconnected laptops and 912network outages. 913In Coda, both the client and server are outside the kernel which makes 914them easier to experiment with. 915Coda is available for several UNIX and non-UNIX platforms. 916See http://www.coda.cs.cmu.edu for more details. 917.Em NOTE : 918You also need to enable the pseudo-device, vcoda, for the Coda 919file system to work. 920.It Cd file-system SMBFS 921.Bq Em EXPERIMENTAL 922Includes code for the SMB/CIFS file system. 923See 924.Xr mount_smbfs 8 925for details. 926.Em NOTE : 927You also need to enable the pseudo-device, nsmb, for the SMB 928file system to work. 929.It Cd file-system PTYFS 930.Bq Em EXPERIMENTAL 931Includes code for a special file system (normally mounted on 932.Pa /dev/pts ) 933in which pseudo-terminal slave devices become visible in the file system. 934See 935.Xr mount_ptyfs 8 936for details. 937.It Cd file-system TMPFS 938Includes code for the efficient memory file system, normally used over 939.Pa /tmp . 940See 941.Xr mount_tmpfs 8 942for details. 943.It Cd file-system PUFFS 944.Bq Em EXPERIMENTAL 945Includes kernel support for the pass-to-userspace framework file system. 946It can be used to implement file system functionality in userspace. 947See 948.Xr puffs 3 949and 950.Xr puffs 4 951for more details. 952This option is required for sshfs: 953.Xr mount_psshfs 8 . 954.El 955.Ss File System Options 956.Bl -ohang 957.It Cd options MAGICLINKS 958Enables the expansion of special strings 959.Po 960beginning with 961.Dq @ 962.Pc 963when traversing symbolic links. 964See 965.Xr symlink 7 966for a list of supported strings. 967Note that this option only controls the enabling of this feature 968by the kernel at boot-up. 969This feature can still be manipulated with the 970.Xr sysctl 8 971command regardless of the setting of this option. 972.It Cd options NFSSERVER 973Include the server side of the 974.Em NFS 975(Network File System) remote file sharing protocol. 976Although the bulk of the code implementing 977.Em NFS 978is kernel based, several user level daemons are needed for it to 979work. 980See 981.Xr mountd 8 982and 983.Xr nfsd 8 984for details. 985.It Cd options QUOTA 986Enables kernel support for file system quotas. 987See 988.Xr quotaon 8 , 989.Xr edquota 8 , 990and 991.Xr quota 1 992for details. 993Note that quotas only work on 994.Dq ffs 995file systems, although 996.Xr rpc.rquotad 8 997permits them to be accessed over 998.Em NFS . 999.It Cd options FFS_EI 1000Enable ``Endian-Independent'' FFS support. 1001This allows a system to mount an FFS file system created for another 1002architecture, at a small performance cost for all FFS file systems. 1003See also 1004.Xr newfs 8 , 1005.Xr fsck_ffs 8 , 1006.Xr dumpfs 8 1007for file system byte order status and manipulation. 1008.It Cd options FFS_NO_SNAPSHOT 1009Disable the 1010.Dq file system snapshot 1011support in FFS file systems. 1012Maybe useful for install media kernels, small memory systems and 1013embedded systems which don't require the snapshot support. 1014.It Cd options NVNODE=integer 1015This option sets the size of the cache used by the name-to-inode translation 1016routines, (a.k.a. the 1017.Fn namei 1018cache, though called by many other names in the kernel source). 1019By default, this cache has 1020.Dv NPROC 1021(set as 20 + 16 * MAXUSERS) * (80 + NPROC / 8) entries. 1022A reasonable way to derive a value of 1023.Dv NVNODE , 1024should you notice a large number of namei cache misses with a tool such as 1025.Xr systat 1 , 1026is to examine your system's current computed value with 1027.Xr sysctl 8 , 1028(which calls this parameter "kern.maxvnodes") and to increase this value 1029until either the namei cache hit rate improves or it is determined that 1030your system does not benefit substantially from an increase in the size of 1031the namei cache. 1032.It Cd options NAMECACHE_ENTER_REVERSE 1033Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1034as well as a normal one. 1035Normally, this is already done for directory vnodes, to speed up the getcwd 1036operation. 1037This option will cause longer hash chains in the reverse cache, and thus 1038slow down getcwd somewhat. 1039However, it does make vnode -\*[Gt] path translations possible in some cases. 1040For now, only useful if strict /proc/#/maps emulation for Linux binaries is 1041required. 1042.It Cd options EXT2FS_SYSTEM_FLAGS 1043This option changes the behavior of the APPEND and IMMUTABLE flags 1044for a file on an 1045.Em EXT2FS 1046file system. 1047Without this option, the superuser or owner of the file can 1048set and clear them. 1049With this option, only the superuser can set them, and 1050they can't be cleared if the securelevel is greater than 0. 1051See also 1052.Xr chflags 1 . 1053.It Cd options NFS_BOOT_BOOTP 1054Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1055information if NFS is used to mount the root file system. 1056See 1057.Xr diskless 8 1058for details. 1059.It Cd options NFS_BOOT_DHCP 1060Same as 1061.Dq NFS_BOOT_BOOTP , 1062but use the DHCP extensions to the 1063BOOTP protocol (RFC 1541). 1064.It Cd options NFS_BOOT_BOOTP_REQFILE 1065Specifies the string sent in the bp_file field of the BOOTP / DHCP 1066request packet. 1067.It Cd options NFS_BOOT_BOOTPARAM 1068Enable use of the BOOTPARAM protocol, consisting of RARP and 1069BOOTPARAM RPC, to get configuration information if NFS 1070is used to mount the root file system. 1071See 1072.Xr diskless 8 1073for details. 1074.It Cd options NFS_BOOT_RWSIZE=value 1075Set the initial NFS read and write sizes for diskless-boot requests. 1076The normal default is 8Kbytes. 1077This option provides a way to lower the value (e.g., to 1024 bytes) 1078as a workaround for buggy network interface cards or boot PROMs. 1079Once booted, the read and write request sizes can be increased by 1080remounting the file system. 1081See 1082.Xr mount_nfs 8 1083for details. 1084.It Cd options NFS_V2_ONLY 1085Reduce the size of the NFS client code by omitting code that's only required 1086for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1087servers. 1088.It Cd options SOFTDEP 1089Enable kernel support for soft-dependencies in FFS filesystems. 1090Softdep improves write performance by aggregating and properly 1091ordering disk metadata writes, achieving near-asynchronous write 1092performance while maintaining the filesystem consistency of 1093synchronous writes. 1094Soft-dependencies are enabled on a per-mount basis. 1095See 1096.Xr mount 8 1097for details. 1098.It Cd options UFS_DIRHASH 1099Increase lookup performance by maintaining in-core hash tables 1100for large directories. 1101.El 1102.Ss Buffer queue strategy options 1103The following options enable alternative buffer queue strategies. 1104.Bl -ohang 1105.It Cd options BUFQ_READPRIO 1106Enable experimental buffer queue strategy for disk I/O. 1107In the default strategy, outstanding disk requests are ordered by 1108sector number and sent to the disk, regardless of whether the 1109operation is a read or write; this option gives priority to issuing 1110read requests over write requests. 1111Although requests may therefore be issued out of sector-order, causing 1112more seeks and thus lower overall throughput, interactive system 1113responsiveness under heavy disk I/O load may be improved, as processes 1114blocking on disk reads are serviced sooner (file writes typically 1115don't cause applications to block). 1116The performance effect varies greatly depending on the hardware, drive 1117firmware, filesystem configuration, workload, and desired performance 1118trade-off. 1119Systems using drive write-cache (most modern IDE disks, by default) 1120are unlikely to benefit and may well suffer; such disks acknowledge 1121writes very quickly, and optimise them internally according to 1122physical layout. 1123Giving these disks as many requests to work with as possible (the 1124standard strategy) will typically produce the best results, especially 1125if the drive has a large cache; the drive will silently complete 1126writes from cache as it seeks for reads. 1127Disks that support a large number of concurrent tagged requests (SCSI 1128disks and many hardware RAID controllers) expose this internal 1129scheduling with tagged responses, and don't block for reads; such 1130disks may not see a noticable difference with either strategy. 1131However, if IDE disks are run with write-cache disabled for safety, 1132writes are not acknowledged until actually completed, and only one 1133request can be outstanding; a large number of small writes in one 1134locality can keep the disk busy, starving reads elsewhere on the disk. 1135Such systems are likely to see the most benefit from this option. 1136Finally, the performance interaction of this option with ffs soft 1137dependencies can be subtle, as that mechanism can drastically alter 1138the workload for filesystem metadata writes. 1139.It Cd options BUFQ_PRIOCSCAN 1140Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1141.It Cd options NEW_BUFQ_STRATEGY 1142Synonym of 1143.Em BUFQ_READPRIO . 1144.El 1145.Ss Miscellaneous Options 1146.Bl -ohang 1147.It Cd options LKM 1148Enable loadable kernel modules. 1149See 1150.Xr lkm 4 1151for details. 1152.Em NOTE : 1153not available on all architectures. 1154.It Cd options MEMORY_DISK_DYNAMIC 1155This option makes the 1156.Xr md 4 1157.Tn RAM 1158disk size dynamically sized. 1159It is incompatible with 1160.Xr mdsetimage 8 . 1161.It Cd options MEMORY_DISK_HOOKS 1162This option allows for some machine dependent functions to be called when 1163the 1164.Xr md 4 1165.Tn RAM 1166disk driver is configured. 1167This can result in automatically loading a 1168.Tn RAM 1169disk from floppy on open (among other things). 1170.It Cd options MEMORY_DISK_IS_ROOT 1171Forces the 1172.Xr md 4 1173.Tn RAM 1174disk to be the root device. 1175This can only be overridden when 1176the kernel is booted in the 'ask-for-root' mode. 1177.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1178Allocates the given number of 512 byte blocks as memory for the 1179.Xr md 4 1180.Tn RAM 1181disk, to be populated with 1182.Xr mdsetimage 8 . 1183.It Cd options MEMORY_DISK_SERVER=0 1184Do not include the interface to a userland memory disk server process. 1185Per default, this option is set to 1, including the support code. 1186Useful for install media kernels. 1187.It Cd options VND_COMPRESSION 1188Enables the 1189.Xr vnd 4 1190driver to also handle compressed images. 1191See 1192.Xr vndcompress 1 , 1193.Xr vnd 4 1194and 1195.Xr vnconfig 8 1196for more information. 1197.It Cd options TFTPROOT 1198Download the root memory disk through TFTP at root mount time. This enable 1199the use of a root 1200.Tn RAM 1201disk without requiring it to be embedded in the kernel using 1202.Xr mdsetimage 8 . 1203The 1204.Tn RAM 1205disk name is obtained using DHCP's filename parameter. 1206This option require 1207.Em MEMORY_DISK_HOOKS , 1208.Em MEMORY_DISK_DYNAMIC , 1209and 1210.Em MEMORY_DISK_IS_ROOT . 1211It is incompatible with 1212.Em MEMORY_DISK_ROOT_SIZE . 1213.It Cd options MALLOC_NOINLINE 1214Time critical fixed size memory allocation is performed with 1215.Fn MALLOC 1216and 1217.Fn FREE . 1218Normally these expand to inline code, but with 1219.Em MALLOC_NOINLINE 1220these call the normal 1221.Fn malloc 1222and 1223.Fn free 1224functions. 1225Useful for install media kernels, small memory systems and embedded systems. 1226.It Cd options HZ=integer 1227On ports that support it, set the system clock frequency (see 1228.Xr hz 9 ) 1229to the supplied value. 1230Handle with care. 1231.It Cd options NTP 1232Turns on in-kernel precision timekeeping support used by software 1233implementing 1234.Em NTP 1235(Network Time Protocol, RFC 1305). 1236The 1237.Em NTP 1238option adds an in-kernel Phase-Locked Loop (PLL) for normal 1239.Em NTP 1240operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1241operation. 1242.Xr ntpd 8 1243will employ a user-level PLL when kernel support is unavailable, 1244but the in-kernel version has lower latency and more precision, and 1245so typically keeps much better time. 1246The interface to the kernel 1247.Em NTP 1248support is provided by the 1249.Xr ntp_adjtime 2 1250and 1251.Xr ntp_gettime 2 1252system calls, which are intended for use by 1253.Xr ntpd 8 1254and are enabled by the option. 1255On systems with sub-microsecond resolution timers, or where (HZ / 100000) 1256is not an integer, the 1257.Em NTP 1258option also enables extended-precision arithmetic to keep track of 1259fractional clock ticks at NTP time-format precision. 1260.It Cd options PPS_SYNC 1261This option enables a kernel serial line discipline for receiving time 1262phase signals from an external reference clock such as a radio clock. 1263(The 1264.Em NTP 1265option (which see) must be on if the 1266.Em PPS_SYNC 1267option is used.) 1268Some reference clocks generate a Pulse Per Second (PPS) signal in 1269phase with their time source. 1270The 1271.Em PPS 1272line discipline receives this signal on either the data leads 1273or the DCD control lead of a serial port. 1274.Em NTP 1275uses the PPS signal to discipline the local clock oscillator to a high 1276degree of precision (typically less than 50 microseconds in time and 12770.1 ppm in accuracy). 1278.Em PPS 1279can also generate a serial output pulse when the system receives a PPS 1280interrupt. 1281This can be used to measure the system interrupt latency and thus calibrate 1282.Em NTP 1283to account for it. 1284Using 1285.Em PPS 1286usually requires a 1287gadget box 1288to convert from TTL to RS-232 signal levels. 1289The gadget box and PPS are described in more detail in the HTML documentation 1290for 1291.Xr ntpd 8 1292in 1293.Pa /usr/share/doc/html/ntp . 1294.It Cd options NO_TSC_TIME 1295Don't use TSC microtime, even if available (i386 only). 1296Improves time behavior under VMware. 1297.It Cd options SETUIDSCRIPTS 1298Allows scripts with the setuid bit set to execute as the effective 1299user rather than the real user, just like binary executables. 1300.Pp 1301.Em NOTE : 1302Using this option will also enable 1303.Em options FDSCRIPTS 1304.It Cd options FDSCRIPTS 1305Allows execution of scripts with the execute bit set, but not the 1306read bit, by opening the file and passing the file descriptor to 1307the shell, rather than the filename. 1308.Pp 1309.Em NOTE : 1310Execute only (non-readable) scripts will have 1311.Va argv[0] 1312set to 1313.Pa /dev/fd/* . 1314What this option allows as far as security is 1315concerned, is the ability to safely ensure that the correct script 1316is run by the interpreter, as it is passed as an already open file. 1317.It Cd options PUCCN 1318Enables treating serial ports found on PCI boards 1319.Xr puc 4 1320as potential console devices. 1321The method for choosing such a console device is port dependent. 1322.It Cd options RTC_OFFSET=integer 1323The kernel (and typically the hardware battery backed-up clock on 1324those machines that have one) keeps time in 1325.Em UTC 1326(Universal Coordinated Time, once known as 1327.Em GMT , 1328or Greenwich Mean Time) 1329and not in the time of the local time zone. 1330The 1331.Em RTC_OFFSET 1332option is used on some ports (such as the i386) to tell the kernel 1333that the hardware clock is offset from 1334.Em UTC 1335by the specified number of minutes. 1336This is typically used when a machine boots several operating 1337systems and one of them wants the hardware clock to run in the 1338local time zone and not in 1339.Em UTC , 1340e.g. 1341.Em RTC_OFFSET=300 1342means 1343the hardware clock is set to US Eastern Time (300 minutes behind 1344.Em UTC ) , 1345and not 1346.Em UTC . 1347(Note: 1348.Em RTC_OFFSET 1349is used to initialize a kernel variable named 1350.Va rtc_offset 1351which is the source actually used to determine the clock offset, and 1352which may be accessed via the kern.rtc_offset sysctl variable. 1353See 1354.Xr sysctl 8 1355and 1356.Xr sysctl 3 1357for details. 1358Since the kernel clock is initialized from the hardware clock very 1359early in the boot process, it is not possible to meaningfully change 1360.Va rtc_offset 1361in system initialization scripts. 1362Changing this value currently may only be done at kernel compile 1363time or by patching the kernel and rebooting). 1364.Pp 1365.Em NOTE : 1366Unfortunately, in many cases where the hardware clock 1367is kept in local time, it is adjusted for Daylight Savings 1368Time; this means that attempting to use 1369.Em RTC_OFFSET 1370to let 1371.Nx 1372coexist with such an operating system, like Windows, 1373would necessitate changing 1374.Em RTC_OFFSET 1375twice a year. 1376As such, this solution is imperfect. 1377.It Cd options KMEMSTATS 1378The kernel memory allocator, 1379.Xr malloc 9 , 1380will keep statistics on its performance if this option is enabled. 1381Unfortunately, this option therefore essentially disables the 1382.Fn MALLOC 1383and 1384.Fn FREE 1385forms of the memory allocator, which are used to enhance the performance 1386of certain critical sections of code in the kernel. 1387This option therefore can lead to a significant decrease in the 1388performance of certain code in the kernel if enabled. 1389Examples of such code include the 1390.Fn namei 1391routine, the 1392.Xr ccd 4 1393driver, 1394and much of the networking code. 1395.It Cd options MAXUPRC=integer 1396Sets the soft 1397.Dv RLIMIT_NPROC 1398resource limit, which specifies the maximum number of simultaneous 1399processes a user is permitted to run, for process 0; 1400this value is inherited by its child processes. 1401It defaults to 1402.Em CHILD_MAX , 1403which is currently defined to be 160. 1404Setting 1405.Em MAXUPRC 1406to a value less than 1407.Em CHILD_MAX 1408is not permitted, as this would result in a violation of the semantics of 1409.St -p1003.1-90 . 1410.It Cd options NOFILE=integer 1411Sets the soft 1412.Dv RLIMIT_NOFILE 1413resource limit, which specifies the maximum number of open 1414file descriptors for each process; 1415this value is inherited by its child processes. 1416It defaults to 1417.Em OPEN_MAX , 1418which is currently defined to be 64. 1419.It Cd options MAXFILES=integer 1420Sets the default value of the 1421.Em kern.maxfiles 1422sysctl variable, which indicates the maximum number of files that may 1423be open in the system. 1424.It Cd options DEFCORENAME=string 1425Sets the default value of the 1426.Em kern.defcorename 1427sysctl variable, otherwise it is set to 1428.Nm %n.core . 1429See 1430.Xr sysctl 8 1431and 1432.Xr sysctl 3 1433for details. 1434.It Cd options RASOPS_CLIPPING 1435Enables clipping within the 1436.Nm rasops 1437raster-console output system. 1438.Em NOTE : 1439only available on architectures that use 1440.Nm rasops 1441for console output. 1442.It Cd options RASOPS_SMALL 1443Removes optimized character writing code from the 1444.Nm rasops 1445raster-console output system. 1446.Em NOTE : 1447only available on architectures that use 1448.Nm rasops 1449for console output. 1450.It Cd options INCLUDE_CONFIG_FILE 1451Embeds the kernel config file used to define the kernel in the kernel 1452binary itself. 1453The embedded data also includes any files directly included by the config 1454file itself, e.g. 1455.Pa GENERIC.local 1456or 1457.Pa std.$MACHINE . 1458The embedded config file can be extracted from the resulting kernel with 1459.Xr config 1 1460.Fl x , 1461or by the following command: 1462.Bd -literal -offset indent 1463strings netbsd | sed -n 's/^_CFG_//p' | unvis 1464.Ed 1465.It Cd options INCLUDE_JUST_CONFIG 1466Similar to the above option, but includes just the actual config file, 1467not any included files. 1468.It Cd options PIPE_SOCKETPAIR 1469Use slower, but smaller socketpair(2)-based pipe implementation instead 1470of default faster, but bigger one. 1471Primarily useful for installation kernels. 1472.It Cd options USERCONF 1473Compiles in the in-kernel device configuration manager. 1474See 1475.Xr userconf 4 1476for details. 1477.It Cd options PERFCTRS 1478Compiles in kernel support for CPU performance-monitoring counters. 1479See 1480.Xr pmc 1 1481for details. 1482.Em NOTE : 1483not available on all architectures. 1484.It Cd options SYSCALL_STATS 1485Count the number of times each system call number is called. 1486The values can be read through the sysctl interface and display using systat 1487.Xr systat 1 . 1488.Em NOTE : 1489not yet available on all architectures. 1490.It Cd options SYSCALL_TIMES 1491Count the time spent (using cpu_counter32()) in each system call. 1492.Em NOTE : 1493Using this option will also enable 1494.Em options SYSCALL_STATS 1495.It Cd options SYSCALL_TIMES_HASCOUNTER 1496Force use of cpu_counter32() even if cpu_hascounter() reports false. 1497Useful for systems where the cycle counter doen't run at a constant rate 1498(e.g. Soekris boxes). 1499.It Cd options XSERVER 1500Compiles in kernel support for 1501.Tn X11 1502on architectures that still use (or can use) the legacy 1503.Em pccons 1504console drivers rather than 1505.Xr wscons 4 . 1506These include bebox, i386, shark. 1507.It Cd options XSERVER_DDB 1508A supplement to XSERVER that adds support for entering 1509.Xr ddb 4 1510while in 1511.Tn X11 . 1512.It Cd options FILEASSOC 1513Support for 1514.Xr fileassoc 9 . 1515.It Cd options FILEASSOC_NHOOKS=integer 1516Number of storage slots per file for 1517.Xr fileassoc 9 . 1518Default is 4. 1519.El 1520.Ss Networking Options 1521.Bl -ohang 1522.It Cd options GATEWAY 1523Enables 1524.Em IPFORWARDING 1525(which see) 1526and (on most ports) increases the size of 1527.Em NMBCLUSTERS 1528(which see). 1529In general, 1530.Em GATEWAY 1531is used to indicate that a system should act as a router, and 1532.Em IPFORWARDING 1533is not invoked directly. 1534(Note that 1535.Em GATEWAY 1536has no impact on protocols other than 1537.Tn IP , 1538such as 1539.Tn CLNP 1540or 1541.Tn XNS ) . 1542.Em GATEWAY 1543option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1544.It Cd options ICMPPRINTFS 1545The 1546.Em ICMPPRINTFS 1547option will enable debugging information to be printed about 1548the 1549.Xr icmp 4 1550protocol. 1551.It Cd options IPFORWARDING=value 1552If 1553.Em value 1554is 1 this enables IP routing behavior. 1555If 1556.Em value 1557is 0 (the default), it disables it. 1558The 1559.Em GATEWAY 1560option sets this to 1 automatically. 1561With this option enabled, the machine will forward IP datagrams destined 1562for other machines between its interfaces. 1563Note that even without this option, the kernel will 1564still forward some packets (such as source routed packets) -- removing 1565.Em GATEWAY 1566and 1567.Em IPFORWARDING 1568is insufficient to stop all routing through a bastion host on a 1569firewall -- source routing is controlled independently. 1570To turn off source routing, use 1571.Em options IPFORWSRCRT=0 1572(which see). 1573Note that IP forwarding may be turned on and off independently of the 1574setting of the 1575.Em IPFORWARDING 1576option through the use of the 1577.Em net.inet.ip.forwarding 1578sysctl variable. 1579If 1580.Em net.inet.ip.forwarding 1581is 1, IP forwarding is on. 1582See 1583.Xr sysctl 8 1584and 1585.Xr sysctl 3 1586for details. 1587.It Cd options IPFORWSRCRT=value 1588If 1589.Em value 1590is set to zero, source routing of IP datagrams is turned off. 1591If 1592.Em value 1593is set to one (the default) or the option is absent, source routed IP 1594datagrams are forwarded by the machine. 1595Note that source routing of IP packets may be turned on and off 1596independently of the setting of the 1597.Em IPFORWSRCRT 1598option through the use of the 1599.Em net.inet.ip.forwsrcrt 1600sysctl variable. 1601If 1602.Em net.inet.ip.forwsrcrt 1603is 1, forwarding of source routed IP datagrams is on. 1604See 1605.Xr sysctl 8 1606and 1607.Xr sysctl 3 1608for details. 1609.It Cd options IFA_STATS 1610Tells the kernel to maintain per-address statistics on bytes sent 1611and received over (currently) internet and appletalk addresses. 1612.\"This can be a fairly expensive operation, so you probably want to 1613.\"keep this disabled. 1614The option is not recommended as it degrades system stability. 1615.It Cd options IFQ_MAXLEN=value 1616Increases the allowed size of the network interface packet queues. 1617The default queue size is 50 packets, and you do not normally need 1618to increase it. 1619.It Cd options IPSELSRC 1620Includes support for source-address selection policies. 1621See 1622.Xr in_getifa 9 . 1623.It Cd options MROUTING 1624Includes support for IP multicast routers. 1625You certainly want 1626.Em INET 1627with this. 1628Multicast routing is controlled by the 1629.Xr mrouted 8 1630daemon. 1631See also option 1632.Cd PIM . 1633.It Cd options PIM 1634Includes support for Protocol Independent Multicast (PIM) routing. 1635You need 1636.Em MROUTING 1637and 1638.Em INET 1639with this. 1640Software using this can be found e.g. in 1641.Pa pkgsrc/net/xorp . 1642.It Cd options INET 1643Includes support for the 1644.Tn TCP/IP 1645protocol stack. 1646You almost certainly want this. 1647See 1648.Xr inet 4 1649for details. 1650.It Cd options INET6 1651Includes support for the 1652.Tn IPv6 1653protocol stack. 1654See 1655.Xr inet6 4 1656for details. 1657Unlike 1658.Em INET , 1659.Em INET6 1660enables multicast routing code as well. 1661This option requires 1662.Em INET 1663at this moment, but it should not. 1664.It Cd options ND6_DEBUG 1665The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1666for debugging IPv6 neighbor discovery protocol handling. 1667See 1668.Xr sysctl 3 1669for details. 1670.It Cd options IPSEC 1671Includes support for the 1672.Tn IPsec 1673protocol. 1674See 1675.Xr ipsec 4 1676for details. 1677.It Cd options IPSEC_DEBUG 1678Enables debugging code in 1679.Tn IPsec 1680stack. 1681See 1682.Xr ipsec 4 1683for details. 1684.It Cd options IPSEC_ESP 1685Includes support for 1686.Tn IPsec 1687.Tn ESP 1688protocol. 1689See 1690.Xr ipsec 4 1691for details. 1692.It Cd options IPSEC_NAT_T 1693Includes support for 1694.Tn IPsec 1695Network Address Translator traversal (NAT-T), as described in RFCs 3947 1696and 3948. 1697This feature might be patent-encumbered in some countries. 1698.It Cd options ALTQ 1699Enabled ALTQ (Alternate Queueing). 1700For simple rate-limiting, use 1701.Xr tbrconfig 8 1702to set up the interface transmission rate. 1703To use queueing disciplines, their appropriate kernel options should also 1704be defined (documented below). 1705Queueing disciplines are managed by 1706.Xr altqd 8 . 1707See 1708.Xr altq 9 1709for details. 1710.It Cd options ALTQ_HFSC 1711Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1712module. 1713HFSC supports both link-sharing and guaranteed real-time services. 1714HFSC employs a service curve based QoS model, and its unique feature 1715is an ability to decouple delay and bandwidth allocation. 1716Requires 1717.Em ALTQ_RED 1718to use the RED queueing discipline on HFSC classes, or 1719.Em ALTQ_RIO 1720to use the RIO queueing discipline on HFSC classes. 1721This option assumes 1722.Em ALTQ . 1723.It Cd options ALTQ_PRIQ 1724Include support for ALTQ-implemented PRIQ (Priority Queueing). 1725PRIQ implements a simple priority-based queueing discipline. 1726A higher priority class is always served first. 1727Requires 1728.Em ALTQ_RED 1729to use the RED queueing discipline on HFSC classes, or 1730.Em ALTQ_RIO 1731to use the RIO queueing discipline on HFSC classes. 1732This option assumes 1733.Em ALTQ . 1734.It Cd options ALTQ_WFQ 1735Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1736WFQ implements a weighted-round robin scheduler for a set of queues. 1737A weight can be assigned to each queue to give a different proportion 1738of the link capacity. 1739A hash function is used to map a flow to one of a set of queues. 1740This option assumes 1741.Em ALTQ . 1742.It Cd options ALTQ_FIFOQ 1743Include support for ALTQ-implemented FIFO queueing. 1744FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1745This option assumes 1746.Em ALTQ . 1747.It Cd options ALTQ_RIO 1748Include support for ALTQ-implemented RIO (RED with In/Out). 1749The original RIO has 2 sets of RED parameters; one for in-profile 1750packets and the other for out-of-profile packets. 1751At the ingress of the network, profile meters tag packets as IN or 1752OUT based on contracted profiles for customers. 1753Inside the network, IN packets receive preferential treatment by 1754the RIO dropper. 1755ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1756PHB of DiffServ (RFC 2597). 1757This option assumes 1758.Em ALTQ . 1759.It Cd options ALTQ_BLUE 1760Include support for ALTQ-implemented Blue buffer management. 1761Blue is another active buffer management mechanism. 1762This option assumes 1763.Em ALTQ . 1764.It Cd options ALTQ_FLOWVALVE 1765Include support for ALTQ-implemented Flowvalve. 1766Flowvalve is a simple implementation of a RED penalty box that identifies 1767and punishes misbehaving flows. 1768This option requires 1769.Em ALTQ_RED 1770and assumes 1771.Em ALTQ . 1772.It Cd options ALTQ_CDNR 1773Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1774packet marking/manipulation. 1775Traffic conditioners are components to meter, mark, or drop incoming 1776packets according to some rules. 1777As opposed to queueing disciplines, traffic conditioners handle incoming 1778packets at an input interface. 1779This option assumes 1780.Em ALTQ . 1781.It Cd options ALTQ_NOPCC 1782Disables use of processor cycle counter to measure time in ALTQ. 1783This option should be defined for a non-Pentium i386 CPU which does not 1784have TSC, SMP (per-CPU counters are not in sync), or power management 1785which affects processor cycle counter. 1786This option assumes 1787.Em ALTQ . 1788.It Cd options ALTQ_IPSEC 1789Include support for IPsec in IPv4 ALTQ. 1790This option assumes 1791.Em ALTQ . 1792.It Cd options ALTQ_JOBS 1793Include support for ALTQ-implemented JoBS (Joint Buffer Management 1794and Scheduling). 1795This option assumes 1796.Em ALTQ . 1797.It Cd options ALTQ_AFMAP 1798Include support for an undocumented ALTQ feature that is used to map an IP 1799flow to an ATM VC (Virtual Circuit). 1800This option assumes 1801.Em ALTQ . 1802.It Cd options ALTQ_LOCALQ 1803Include support for ALTQ-implemented local queues. 1804Its practical use is undefined. 1805Assumes 1806.Em ALTQ . 1807.It Cd options SUBNETSARELOCAL 1808Sets default value for net.inet.ip.subnetsarelocal variable, which 1809controls whether non-directly-connected subnets of connected networks 1810are considered "local" for purposes of choosing the MSS for a TCP 1811connection. 1812This is mostly present for historic reasons and completely irrelevant if 1813you enable Path MTU discovery. 1814.It Cd options HOSTZEROBROADCAST 1815Sets default value for net.inet.ip.hostzerobroadcast variable, which 1816controls whether the zeroth host address of each connected subnet is 1817also considered a broadcast address. 1818Default value is "1", for compatibility with old systems; if this is 1819set to zero on all hosts on a subnet, you should be able to fit an extra 1820host per subnet on the 1821".0" address. 1822.It Cd options MCLSHIFT=value 1823This option is the base-2 logarithm of the size of mbuf clusters. 1824The 1825.Bx 1826networking stack keeps network packets in a linked 1827list, or chain, of kernel buffer objects called mbufs. 1828The system provides larger mbuf clusters as an optimization for 1829large packets, instead of using long chains for large packets. 1830The mbuf cluster size, 1831or 1832.Em MCLBYTES , 1833must be a power of two, and is computed as two raised to the power 1834.Em MCLSHIFT . 1835On systems with Ethernet network adaptors, 1836.Em MCLSHIFT 1837is often set to 11, giving 2048-byte mbuf clusters, large enough to 1838hold a 1500-byte 1839.Tn Ethernet 1840frame in a single cluster. 1841Systems with network interfaces supporting larger frame sizes like 1842.Tn ATM , 1843.Tn FDDI , 1844or 1845.Tn HIPPI 1846may perform better with 1847.Em MCLSHIFT 1848set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1849respectively. 1850.It Cd options NS 1851Include support for the 1852.Tn Xerox 1853.Tn XNS 1854protocol stack. 1855See 1856.Xr ns 4 1857for details. 1858.It Cd options ISO,TPIP 1859Include support for the ubiquitous 1860.Tn OSI 1861protocol stack. 1862See 1863.Xr iso 4 1864for details. 1865This option assumes 1866.Em INET . 1867.It Cd options EON 1868Include support for tunneling 1869.Tn OSI 1870protocols over 1871.Tn IP . 1872Known to be broken, or at least very fragile, and undocumented. 1873.It Cd options NETATALK 1874Include support for the 1875.Tn AppleTalk 1876protocol stack. 1877The kernel provides provision for the 1878.Em Datagram Delivery Protocol 1879(DDP), providing SOCK_DGRAM support and 1880.Tn AppleTalk 1881routing. 1882This stack is used by the 1883.Em NETATALK 1884package, which adds support for 1885.Tn AppleTalk 1886server services via user libraries and applications. 1887.It Cd options BLUETOOTH 1888Include support for the 1889.Tn Bluetooth 1890protocol stack. 1891See 1892.Xr bluetooth 4 1893for details. 1894.It Cd options IPNOPRIVPORTS 1895Normally, only root can bind a socket descriptor to a so-called 1896.Dq privileged 1897.Tn TCP 1898port, that is, a port number in the range 0-1023. 1899This option eliminates those checks from the kernel. 1900This can be useful if there is a desire to allow daemons without 1901privileges to bind those ports, e.g., on firewalls. 1902The security tradeoffs in doing this are subtle. 1903This option should only be used by experts. 1904.It Cd options TCP_COMPAT_42 1905.Tn TCP 1906bug compatibility with 1907.Bx 4.2 . 1908In 1909.Bx 4.2 , 1910.Tn TCP 1911sequence numbers were 32-bit signed values. 1912Modern implementations of TCP use unsigned values. 1913This option clamps the initial sequence number to start in 1914the range 2^31 rather than the full unsigned range of 2^32. 1915Also, under 1916.Bx 4.2 , 1917keepalive packets must contain at least one byte or else 1918the remote end would not respond. 1919.It Cd options TCP_DEBUG 1920Record the last 1921.Em TCP_NDEBUG 1922TCP packets with SO_DEBUG set, and decode to the console if 1923.Em tcpconsdebug 1924is set. 1925.It Cd options TCP_NDEBUG 1926Number of packets to record for 1927.Em TCP_DEBUG . 1928Defaults to 100. 1929.It Cd options TCP_SENDSPACE=value 1930.It Cd options TCP_RECVSPACE=value 1931These options set the max TCP window size to other sizes than the default. 1932The TCP window sizes can be altered via 1933.Xr sysctl 8 1934as well. 1935.It Cd options TCP_INIT_WIN=value 1936This option sets the initial TCP window size for non-local connections, 1937which is used when the transmission starts. 1938The default size is 1, but if the machine should act more aggressively, 1939the initial size can be set to some other value. 1940The initial TCP window size can be set via 1941.Xr sysctl 8 1942as well. 1943.It Cd options PFIL_HOOKS 1944This option turns on the packet filter interface hooks. 1945See 1946.Xr pfil 9 1947for details. 1948This option assumes 1949.Em INET . 1950.It Cd options IPFILTER_LOG 1951This option, in conjunction with 1952.Em pseudo-device ipfilter , 1953enables logging of IP packets using ip-filter. 1954.It Cd options IPFILTER_DEFAULT_BLOCK 1955This option sets the default policy of ip-filter. 1956If it is set, ip-filter will block packets by default. 1957.It Cd options BRIDGE_IPF 1958This option causes 1959.Em bridge 1960devices to use the IP and/or IPv6 filtering hooks, forming 1961a link-layer filter that uses protocol-layer rules. 1962This option assumes the presence of 1963.Em pseudo-device ipfilter . 1964.It Cd options MBUFTRACE 1965This option can help track down mbuf leaks. 1966When enabled, mbufs are tagged with the devices and protocols using them, 1967which slightly decreases network performance. 1968This additional information can be viewed with 1969.Xr netstat 1 : 1970.Dl Ic netstat Fl mssv 1971Not all devices or protocols support this option. 1972.El 1973.Ss Sysctl Related Options 1974.Bl -ohang 1975.It Cd options SYSCTL_DISALLOW_CREATE 1976Disallows the creation or deletion of nodes from the sysctl tree, as 1977well as the assigning of descriptions to nodes that lack them, by any 1978process. 1979These operations are still available to kernel sub-systems, including 1980loadable kernel modules. 1981.It Cd options SYSCTL_DISALLOW_KWRITE 1982Prevents processes from adding nodes to the sysctl tree that make 1983existing kernel memory areas writeable. 1984Sections of kernel memory can still be read and new nodes that own 1985their own data may still be writeable. 1986.It Cd options SYSCTL_DEBUG_SETUP 1987Causes the SYSCTL_SETUP routines to print a brief message when they 1988are invoked. 1989This is merely meant as an aid in determining the order in which 1990sections of the tree are created. 1991.It Cd options SYSCTL_DEBUG_CREATE 1992Prints a message each time 1993.Fn sysctl_create , 1994the function that adds nodes to the tree, is called. 1995.It Cd options SYSCTL_INCLUDE_DESCR 1996Causes the kernel to include short, human readable descriptions for 1997nodes in the sysctl tree. 1998The descriptions can be retrieved programmatically (see 1999.Xr sysctl 3 ) , 2000or by the sysctl binary itself (see 2001.Xr sysctl 8 ) . 2002The descriptions are meant to give an indication of the purpose and/or 2003effects of a given node's value, not replace the documentation for the 2004given subsystem as a whole. 2005.El 2006.Ss System V IPC Options 2007.Bl -ohang 2008.It Cd options SYSVMSG 2009Includes support for 2010.At V 2011style message queues. 2012See 2013.Xr msgctl 2 , 2014.Xr msgget 2 , 2015.Xr msgrcv 2 , 2016.Xr msgsnd 2 . 2017.It Cd options SYSVSEM 2018Includes support for 2019.At V 2020style semaphores. 2021See 2022.Xr semctl 2 , 2023.Xr semget 2 , 2024.Xr semop 2 . 2025.It Cd options SEMMNI=value 2026Sets the number of 2027.At V 2028style semaphore identifiers. 2029The GENERIC config file for your port will have the default. 2030.It Cd options SEMMNS=value 2031Sets the number of 2032.At V 2033style semaphores in the system. 2034The GENERIC config file for your port will have the default. 2035.It Cd options SEMUME=value 2036Sets the maximum number of undo entries per process for 2037.At V 2038style semaphores. 2039The GENERIC config file for your port will have the default. 2040.It Cd options SEMMNU=value 2041Sets the number of undo structures in the system for 2042.At V 2043style semaphores. 2044The GENERIC config file for your port will have the default. 2045.It Cd options SYSVSHM 2046Includes support for 2047.At V 2048style shared memory. 2049See 2050.Xr shmat 2 , 2051.Xr shmctl 2 , 2052.Xr shmdt 2 , 2053.Xr shmget 2 . 2054.It Cd options SHMMAXPGS=value 2055Sets the maximum number of 2056.At V 2057style shared memory pages that are available through the 2058.Xr shmget 2 2059system call. 2060Default value is 1024 on most ports. 2061See 2062.Pa /usr/include/machine/vmparam.h 2063for the default. 2064.El 2065.Ss VM Related Options 2066.Bl -ohang 2067.It Cd options NMBCLUSTERS=value 2068The number of mbuf clusters the kernel supports. 2069Mbuf clusters are MCLBYTES in size (usually 2k). 2070This is used to compute the size of the kernel VM map 2071.Em mb_map , 2072which maps mbuf clusters. 2073Default on most ports is 1024 (2048 with 2074.Dq options GATEWAY 2075). 2076See 2077.Pa /usr/include/machine/param.h 2078for exact default information. 2079Increase this value if you get 2080.Dq mclpool limit reached 2081messages. 2082.It Cd options NKMEMPAGES=value 2083.It Cd options NKMEMPAGES_MIN=value 2084.It Cd options NKMEMPAGES_MAX=value 2085Size of kernel VM map 2086.Em kmem_map , 2087in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2088from the 2089.Xr sysctl 8 2090variable 2091.Em hw.pagesize 2092). 2093This VM map is used to map the kernel malloc arena. 2094The kernel attempts to auto-size this map based on the amount of 2095physical memory in the system. 2096Platform-specific code may place bounds on this computed size, 2097which may be viewed with the 2098.Xr sysctl 8 2099variable 2100.Em vm.nkmempages . 2101See 2102.Pa /usr/include/machine/param.h 2103for the default upper and lower bounds. 2104The related options 2105.Sq NKMEMPAGES_MIN 2106and 2107.Sq NKMEMPAGES_MAX 2108allow the bounds to be overridden in the kernel configuration file. 2109These options are provided in the event the computed value is 2110insufficient resulting in an 2111.Dq out of space in kmem_map 2112panic. 2113.It Cd options SB_MAX=value 2114Sets the max size in bytes that a socket buffer is allowed to occupy. 2115The default is 256k, but sometimes it needs to be increased, for example 2116when using large TCP windows. 2117This option can be changed via 2118.Xr sysctl 8 2119as well. 2120.It Cd options SOMAXKVA=value 2121Sets the maximum size of kernel virtual memory that the socket buffers 2122are allowed to use. 2123The default is 16MB, but in situations where for example large TCP 2124windows are used this value must also be increased. 2125This option can be changed via 2126.Xr sysctl 8 2127as well. 2128.It Cd options BUFCACHE=value 2129Size of the buffer cache as a percentage of total available 2130.Tn RAM . 2131Ignored if BUFPAGES is also specified. 2132.It Cd options NBUF=value 2133Sets the number of buffer headers available, i.e., the number of 2134open files that may have a buffer cache entry. 2135Each buffer header 2136requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2137The default value is machine dependent, but is usually equal to the 2138value of BUFPAGES. 2139If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2140then NBUF may be reduced at run time so that the storage allocated 2141for buffer headers doesn't exceed that limit. 2142.It Cd options BUFPAGES=value 2143These options set the number of pages available for the buffer cache. 2144Their default value is a machine dependent value, often calculated as 2145between 5% and 10% of total available 2146.Tn RAM . 2147.It Cd options MAXTSIZ=bytes 2148Sets the maximum size limit of a process' text segment. 2149See 2150.Pa /usr/include/machine/vmparam.h 2151for the port-specific default. 2152.It Cd options DFLDSIZ=bytes 2153Sets the default size limit of a process' data segment, the value that 2154will be returned as the soft limit for 2155.Dv RLIMIT_DATA 2156(as returned by 2157.Xr getrlimit 2 ) . 2158See 2159.Pa /usr/include/machine/vmparam.h 2160for the port-specific default. 2161.It Cd options MAXDSIZ=bytes 2162Sets the maximum size limit of a process' data segment, the value that 2163will be returned as the hard limit for 2164.Dv RLIMIT_DATA 2165(as returned by 2166.Xr getrlimit 2 ) . 2167See 2168.Pa /usr/include/machine/vmparam.h 2169for the port-specific default. 2170.It Cd options DFLSSIZ=bytes 2171Sets the default size limit of a process' stack segment, the value that 2172will be returned as the soft limit for 2173.Dv RLIMIT_STACK 2174(as returned by 2175.Xr getrlimit 2 ) . 2176See 2177.Pa /usr/include/machine/vmparam.h 2178for the port-specific default. 2179.It Cd options MAXSSIZ=bytes 2180Sets the maximum size limit of a process' stack segment, the value that 2181will be returned as the hard limit for 2182.Dv RLIMIT_STACK 2183(as returned by 2184.Xr getrlimit 2 ) . 2185See 2186.Pa /usr/include/machine/vmparam.h 2187for the port-specific default. 2188.It Cd options DUMP_ON_PANIC=integer 2189Defaults to one. 2190If set to zero, the kernel will not dump to the dump device when 2191it panics, though dumps can still be forced via 2192.Xr ddb 4 2193with the 2194.Dq sync 2195command. 2196Note that this sets the value of the 2197.Em kern.dump_on_panic 2198.Xr sysctl 3 2199variable which may be changed at run time -- see 2200.Xr sysctl 8 2201for details. 2202.It Cd options USE_TOPDOWN_VM 2203User space memory allocations (as made by 2204.Xr mmap 2 ) 2205will be arranged in a 2206.Dq top down 2207fashion instead of the traditional 2208.Dq upwards from MAXDSIZ \+ vm_daddr 2209method. 2210This includes the placement of 2211.Xr ld.so 1 . 2212Arranging memory in this manner allows either (or both of) the heap or 2213.Xr mmap 2 2214allocated space to grow larger than traditionally possible. 2215This option is not available on all ports, but is instead expected to be 2216offered on a port-by-port basis, after which some ports will commit to 2217using it by default. 2218See the files 2219.Pa /usr/include/uvm/uvm_param.h 2220for some implementation details, and 2221.Pa /usr/include/machine/vmparam.h 2222for port specific details including availability. 2223.It Cd options VMSWAP 2224Enable paging device/file support. 2225This option is on by default. 2226.It Cd options PDPOLICY_CLOCKPRO 2227Use CLOCK-Pro, an alternative page replace policy. 2228.El 2229.Ss Security Options 2230.Bl -ohang 2231.It Cd options INSECURE 2232Hardwires the kernel security level at \-1. 2233This means that the system 2234always runs in secure level \-1 mode, even when running multiuser. 2235See the manual page for 2236.Xr init 8 2237for details on the implications of this. 2238The kernel secure level may manipulated by the superuser by altering the 2239.Em kern.securelevel 2240.Xr sysctl 3 2241variable (the secure level may only be lowered by a call from process ID 1, 2242i.e., 2243.Xr init 8 ) . 2244See also 2245.Xr sysctl 8 2246and 2247.Xr sysctl 3 . 2248.It Cd options VERIFIED_EXEC_FP_MD5 2249Enables support for MD5 hashes in Veriexec. 2250.It Cd options VERIFIED_EXEC_FP_SHA1 2251Enables support for SHA1 hashes in Veriexec. 2252.It Cd options VERIFIED_EXEC_FP_RMD160 2253Enables support for RMD160 hashes in Veriexec. 2254.It Cd options VERIFIED_EXEC_FP_SHA256 2255Enables support for SHA256 hashes in Veriexec. 2256.It Cd options VERIFIED_EXEC_FP_SHA384 2257Enables support for SHA384 hashes in Veriexec. 2258.It Cd options VERIFIED_EXEC_FP_SHA512 2259Enables support for SHA512 hashes in Veriexec. 2260.It Cd options PAX_MPROTECT=value 2261Enables PaX MPROTECT, 2262.Xr mprotect 2 2263restrictions from the PaX project. 2264.Pp 2265The 2266.Ar value 2267is the default value for the 2268.Em global 2269knob, see 2270.Xr sysctl 3 . 2271If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2272using 2273.Xr paxctl 8 . 2274If 1, PaX MPROTECT will be enabled for all programs. 2275Programs can be exempted using 2276.Xr paxctl 8 . 2277.Pp 2278See 2279.Xr security 8 2280for more details. 2281.It Cd options PAX_SEGVGUARD=value 2282Enables PaX Segvguard. 2283.Pp 2284The 2285.Ar value 2286is the default value for the 2287.Em global 2288knob, see 2289.Xr sysctl 3 . 2290If 0, PaX Segvguard will be enabled only if explicitly set on programs 2291using 2292.Xr paxctl 8 . 2293If 1, PaX Segvguard will be enabled to all programs, and exemption can 2294be done using 2295.Xr paxctl 8 . 2296.Pp 2297See 2298.Xr security 8 2299for more details. 2300.El 2301.Ss amiga-specific Options 2302.Bl -ohang 2303.It Cd options BB060STUPIDROM 2304When the bootloader (which passes 2305.Tn AmigaOS 2306.Tn ROM 2307information) claims we have a 68060 2308.Tn CPU 2309without 2310.Tn FPU , 2311go look into the Processor Configuration Register (PCR) to find out. 2312You need this with 2313.Tn Amiga 2314.Tn ROM Ns s 2315up to (at least) V40.xxx (OS3.1), 2316when you boot via the bootblocks and don't have a DraCo. 2317.It Cd options IOBZCLOCK=frequency 2318The IOBlix boards come with two different serial master clocks: older ones 2319use 24 MHz, newer ones use 22.1184 MHz. 2320The driver normally assumes the latter. 2321If your board uses 24 MHz, you can recompile your kernel with 2322options IOBZCLOCK=24000000 2323or patch the kernel variable 2324.Tn iobzclock 2325to the same value. 2326.It Cd options LIMITMEM=value 2327If there, limit the part of the first memory bank used by 2328.Nx 2329to value megabytes. 2330Default is unlimited. 2331.It Cd options NKPTADD=addvalue 2332.It Cd options NKPTADDSHIFT=shiftvalue 2333The 2334.Tn CPU 2335specific 2336.Tn MMU 2337table for the kernel is pre-allocated at kernel startup time. 2338Part of it is scaled with 2339.Va maxproc , 2340to have enough room to hold the user program 2341.Tn MMU 2342tables; the second part is a fixed amount for the kernel itself. 2343.Pp 2344The third part accounts for the size of the file buffer cache. 2345Its size is either 2346.Dv NKPTADD 2347pages (if defined) or memory size in bytes divided by two to 2348the power of 2349.Dv NKPTADDSHIFT . 2350The default is undefined 2351.Dv NKPTADD 2352and 2353.Dv NKPTADDSHIFT=24 , 2354allowing for 16 buffers per megabyte of main memory (while 2355a GENERIC kernel allocates about half of that). 2356When you get "can't get KPT page" panics, you should increase 2357.Dv NKPTADD 2358(if defined), or decrease 2359.Dv NKPTADDSHIFT 2360by one. 2361.It Cd options P5PPC68KBOARD 2362Add special support for Phase5 mixed 68k+PPC boards. 2363Currently, this only affects rebooting from 2364.Nx 2365and is only needed on 68040+PPC, not on 236668060+PPC; without this, affected machines will hang after 2367.Nx 2368has shut 2369down and will only restart after a keyboard reset or a power cycle. 2370.El 2371.Ss arm32-specific Options 2372.Bl -ohang 2373.It Cd options FRENCH_KBD 2374Include translation for French keyboards when using 2375.Em pccons 2376on a Shark. 2377.It Cd options FINNISH_KBD 2378Include translation for Finnish keyboards when using 2379.Em pccons 2380on a Shark. 2381.It Cd options GERMAN_KBD 2382Include translation for German keyboards when using 2383.Em pccons 2384on a Shark. 2385.It Cd options NORWEGIAN_KBD 2386Include translation for French keyboards when using 2387.Em pccons 2388on a Shark. 2389.El 2390.Ss amd64-specific Options 2391.Bl -ohang 2392.It Cd options ENHANCED_SPEEDSTEP 2393Include support for the 2394.Tn Enhanced SpeedStep Technology 2395present in newer 2396.Tn CPU Ns s . 2397.It Cd options EST_FREQ_USERWRITE 2398Allow any user to change the frequency of an 2399.Tn Enhanced SpeedStep Technology 2400capable 2401.Tn CPU . 2402.It Cd options INTEL_ONDEMAND_CLOCKMOD 2403This enables the On Demand Clock Modulation by software 2404on Intel 2405.Tn CPUs 2406supporting the Thermal Monitor feature (TM). 2407You can select the duty cycle with 2408.Xr sysctl 8 2409in the node 2410.Em machdep.clockmod 2411if supported. 2412.It Cd options POWERNOW_K8 2413Include support for AMD Athlon 64 PowerNow! and Cool`n'Quiet 2414Technology, used to change the cpu voltage and frequency 2415on the fly. 2416.El 2417.Ss atari-specific Options 2418.Bl -ohang 2419.It Cd options DISKLABEL_AHDI 2420Include support for AHDI (native Atari) disklabels. 2421.It Cd options DISKLABEL_NBDA 2422Include support for 2423.Nx Ns Tn /atari 2424labels. 2425If you don't set this option, it will be set automatically. 2426.Nx Ns Tn /atari 2427will not work without it. 2428.It Cd options FALCON_SCSI 2429Include support for the 5380-SCSI configuration as found on the Falcon. 2430.It Cd options RELOC_KERNEL 2431If set, the kernel will relocate itself to TT-RAM, if possible. 2432This will give you a slightly faster system. 2433.Em Beware 2434that on some TT030 systems, 2435the system will frequently dump with MMU-faults with this option enabled. 2436.It Cd options SERCONSOLE 2437Allow the modem1-port to act as the system-console. 2438A carrier should be active on modem1 during system boot to active 2439the console functionality. 2440.It Cd options TT_SCSI 2441Include support for the 5380-SCSI configuration as found on the TT030 2442and Hades. 2443.El 2444.Ss i386-specific Options 2445.Bl -ohang 2446.It Cd options I386_CPU,I486_CPU,I586_CPU,I686_CPU 2447Include support for a particular class of 2448.Tn CPU 2449.Po 2450.Tn i386 , 2451.Tn i486 , 2452.Tn Pentium , 2453or 2454.Tn Pentium Pro 2455.Pc . 2456If the appropriate class for your 2457.Tn CPU 2458is not configured, the kernel will use the highest class available 2459that will work. 2460In general, using the correct 2461.Tn CPU 2462class will result in the best performance. 2463At least one of these options must be present. 2464.It Cd options ENHANCED_SPEEDSTEP 2465Include support for the 2466.Tn Enhanced SpeedStep Technology 2467present in newer 2468.Tn CPU Ns s . 2469.It Cd options EST_FREQ_USERWRITE 2470Allow any user to change the frequency of an 2471.Tn Enhanced SpeedStep Technology 2472capable 2473.Tn CPU . 2474.It Cd options INTEL_ONDEMAND_CLOCKMOD 2475This enables the On Demand Clock Modulation by software 2476on Intel 2477.Tn CPUs 2478supporting the Thermal Monitor feature (TM). 2479You can select the duty cycle with 2480.Xr sysctl 8 2481in the node 2482.Em machdep.clockmod 2483if supported. 2484.It Cd options POWERNOW_K7 2485Include support for the AMD 2486.Tn PowerNow! Technology 2487present in AMD Athlon Mobile processors. 2488.It Cd options VIA_PADLOCK 2489Include support for the 2490.Tn AES 2491encryption instructions of the 2492.Tn VIA PadLock Security engine , 2493which is attached as a provider to the opencrypto framework. 2494.It Cd options CPURESET_DELAY=value 2495Specifies the time (in millisecond) to wait before doing a hardware reset 2496in the last phase of a reboot. 2497This gives the user a chance to see error messages from the shutdown 2498operations (like NFS unmounts, buffer cache flush, etc ...). 2499Setting this to 0 will disable the delay. 2500Default is 2 seconds. 2501.It Cd options MATH_EMULATE 2502Include the floating point emulator. 2503This is useful only for 2504.Tn CPU Ns s 2505that lack an 2506internal Floating Point Unit 2507.Pq Tn FPU 2508or co-processor. 2509.It Cd options VM86 2510Include support for virtual 8086 mode, used by 2511.Tn DOS 2512emulators and X servers to run BIOS code, e.g., for some VESA routines. 2513.It Cd options USER_LDT 2514Include i386-specific system calls for modifying the local descriptor table, 2515used by Windows emulators. 2516.It Cd options REALBASEMEM=integer 2517Overrides the base memory size passed in from the boot block. 2518(Value given in kilobytes.) 2519Use this option only if the boot block reports the size incorrectly. 2520(Note that some 2521.Tn BIOS Ns es 2522put the extended 2523.Tn BIOS 2524data area at the top of base memory, and therefore report a smaller 2525base memory size to prevent programs overwriting it. 2526This is correct behavior, and you should not use the 2527.Em REALBASEMEM 2528option to access this memory). 2529.It Cd options REALEXTMEM=integer 2530Overrides the extended memory size passed in from the boot block. 2531(Value given in kilobytes. 2532Extended memory does not include the first megabyte.) 2533Use this option only if the boot block reports the size incorrectly. 2534.It Cd options FRENCH_KBD,FINNISH_KBD,GERMAN_KBD,NORWEGIAN_KBD 2535Select a non-US keyboard layout for the 2536.Em pccons 2537console driver. 2538.It Cd options CYRIX_CACHE_WORKS 2539Relevant only to the Cyrix 486DLC CPU. 2540This option is used to turn on the cache in hold-flush mode. 2541It is not turned on by default because it is known to have problems in 2542certain motherboard implementations. 2543.It Cd options CYRIX_CACHE_REALLY_WORKS 2544Relevant only to the Cyrix 486DLC CPU. 2545This option is used to turn on the cache in write-back mode. 2546It is not turned on by default because it is known to have problems in 2547certain motherboard implementations. 2548In order for this option to take effect, option 2549.Em CYRIX_CACHE_WORKS 2550must also be specified. 2551.It Cd options PCIBIOS 2552Enable support for initializing the 2553.Tn PCI 2554bus using information from the 2555.Tn BIOS . 2556See 2557.Xr pcibios 4 2558for details. 2559.It Cd options KSTACK_CHECK_DR0 2560Detect kernel stack overflow using DR0 register. 2561This option uses DR0 register exclusively so you can't use DR0 register for 2562other purpose (e.g., hardware breakpoint) if you turn this on. 2563.It Cd options MTRR 2564Include support for accessing MTRR registers from user-space. 2565See 2566.Xr i386_get_mtrr 2 . 2567.It Cd options BEEP_ONHALT 2568Make the system speaker emit several beeps when it is completely safe to 2569power down the computer after a 2570.Xr halt 8 2571command. 2572Requires 2573.Xr sysbeep 4 2574support. 2575.It Cd options BEEP_ONHALT_COUNT=times 2576Number of times to beep the speaker when 2577.Cd options BEEP_ONHALT 2578is enabled. 2579Defaults to 3. 2580.It Cd options BEEP_ONHALT_PITCH=hz 2581The tone frequency used when 2582.Cd options BEEP_ONHALT 2583option, in hertz. 2584Defaults to 1500. 2585.It Cd options BEEP_ONHALT_PERIOD=msecs 2586The duration of each beep when 2587.Cd options BEEP_ONHALT 2588is enabled, in milliseconds. 2589Defaults to 250. 2590.It Cd options MULTIBOOT 2591Makes the kernel Multiboot-compliant, allowing it to be booted through 2592a Multiboot-compliant boot manager such as GRUB. 2593See 2594.Xr multiboot 8 2595for more information. 2596.El 2597.Ss isa-specific Options 2598Options specific to 2599.Xr isa 4 2600busses. 2601.Bl -ohang 2602.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2603Control the section of IO bus space used for PCMCIA bus space mapping. 2604Ideally the probed defaults are satisfactory, however in practice 2605that is not always the case. 2606See 2607.Xr pcmcia 4 2608for details. 2609.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2610Controls the allowable interrupts that may be used for 2611.Tn PCMCIA 2612devices. 2613This mask is a logical-or of power-of-2s of allowable interrupts: 2614.Bd -literal -offset 04n 2615.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2616 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2617 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2618 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2619 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2620.Ed 2621.It Cd options PCKBC_CNATTACH_SELFTEST 2622Perform a self test of the keyboard controller before attaching it as a 2623console. 2624This might be necessary on machines where we boot on cold iron, and 2625pckbc refuses to talk until we request a self test. 2626Currently only the netwinder port uses it. 2627.It Cd options PCKBD_CNATTACH_MAY_FAIL 2628If this option is set the PS/2 keyboard will not be used as the console 2629if it cannot be found during boot. 2630This allows other keyboards, like USB, to be the console keyboard. 2631.It Cd options PCKBD_LAYOUT=layout 2632Sets the default keyboard layout, see 2633.Xr pckbd 4 . 2634.El 2635.Ss m68k-specific Options 2636.Bl -ohang 2637.It Cd options FPU_EMULATE 2638Include support for MC68881/MC68882 emulator. 2639.It Cd options FPSP 2640Include support for 68040 floating point. 2641.It Cd options M68020,M68030,M68040,M68060 2642Include support for a specific 2643.Tn CPU , 2644at least one (the one you are using) should be specified. 2645.It Cd options M060SP 2646Include software support for 68060. 2647This provides emulation of unimplemented 2648integer instructions as well as emulation of unimplemented floating point 2649instructions and data types and software support for floating point traps. 2650.El 2651.Ss powerpc-specific Options (OEA Only) 2652.Bl -ohang 2653.It Cd options PMAP_MEMLIMIT=value 2654Limit the amount of memory seen by the kernel to 2655.Ar value 2656bytes. 2657.It Cd options PTEGCOUNT=value 2658Specify the size of the page table as 2659.Ar value 2660PTE groups. 2661Normally, one PTEG is allocated per physical page frame. 2662.El 2663.Ss sparc-specific Options 2664.Bl -ohang 2665.It Cd options AUDIO_DEBUG 2666Enable simple event debugging of the logging of the 2667.Xr audio 4 2668device. 2669.It Cd options BLINK 2670Enable blinking of LED. 2671Blink rate is full cycle every N seconds for 2672N \*[Lt] then current load average. 2673See 2674.Xr getloadavg 3 . 2675.\" .It Cd options COLORFONT_CACHE 2676.\" What does this do? 2677.It Cd options COUNT_SW_LEFTOVERS 2678Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2679sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2680variables accessible from 2681.Xr ddb 4 . 2682See 2683.Xr sw 4 . 2684.It Cd options DEBUG_ALIGN 2685Adds debugging messages calls when user-requested alignment fault 2686handling happens. 2687.It Cd options DEBUG_EMUL 2688Adds debugging messages calls for emulated floating point and 2689alignment fixing operations. 2690.It Cd options DEBUG_SVR4 2691Prints registers messages calls for emulated SVR4 getcontext and 2692setcontext operations. 2693See 2694.Em options COMPAT_SVR4 . 2695.It Cd options EXTREME_DEBUG 2696Adds debugging functions callable from 2697.Xr ddb 4 . 2698The debug_pagetables, test_region and print_fe_map 2699functions print information about page tables for the SUN4M 2700platforms only. 2701.It Cd options EXTREME_EXTREME_DEBUG 2702Adds extra info to 2703.Em options EXTREME_DEBUG . 2704.It Cd options FPU_CONTEXT 2705Make 2706.Em options COMPAT_SVR4 2707getcontext and setcontext include floating point registers. 2708.It Cd options MAGMA_DEBUG 2709Adds debugging messages to the 2710.Xr magma 4 2711device. 2712.It Cd options RASTERCONS_FULLSCREEN 2713Use the entire screen for the console. 2714.It Cd options RASTERCONS_SMALLFONT 2715Use the Fixed font on the console, instead of the normal font. 2716.It Cd options SUN4 2717Support sun4 class machines. 2718.It Cd options SUN4C 2719Support sun4c class machines. 2720.It Cd options SUN4M 2721Support sun4m class machines. 2722.It Cd options SUN4_MMU3L 2723.\" XXX ??? 2724Enable support for sun4 3-level MMU machines. 2725.It Cd options V9 2726Enable SPARC V9 assembler in 2727.Xr ddb 4 . 2728.El 2729.Ss sparc64-specific Options 2730.Bl -ohang 2731.It Cd options AUDIO_DEBUG 2732Enable simple event debugging of the logging of the 2733.Xr audio 4 2734device. 2735.It Cd options BLINK 2736Enable blinking of LED. 2737Blink rate is full cycle every N seconds for 2738N \*[Lt] then current load average. 2739See 2740.Xr getloadavg 3 . 2741.El 2742.Ss x68k-specific Options 2743.Bl -ohang 2744.It Cd options EXTENDED_MEMORY 2745Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2746.It Cd options JUPITER 2747Include support for Jupiter-X MPU accelerator 2748.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2749Use the built-in serial port as the system-console. 2750Speed is specified in bps, defaults to 9600. 2751.It Cd options ITE_KERNEL_ATTR=value 2752Set the kernel message attribute for ITE. 2753Value, an integer, is a logical or of the following values: 2754.Bl -tag -width 4n -compact -offset indent 2755.It 1 2756color inversed 2757.It 2 2758underlined 2759.It 4 2760bolded 2761.El 2762.El 2763.\" The following requests should be uncommented and used where appropriate. 2764.\" .Sh FILES 2765.\" .Sh EXAMPLES 2766.Sh SEE ALSO 2767.Xr config 1 , 2768.Xr gdb 1 , 2769.Xr ktrace 1 , 2770.Xr pmc 1 , 2771.Xr quota 1 , 2772.Xr vndcompress 1 , 2773.Xr gettimeofday 2 , 2774.Xr i386_get_mtrr 2 , 2775.Xr i386_iopl 2 , 2776.Xr msgctl 2 , 2777.Xr msgget 2 , 2778.Xr msgrcv 2 , 2779.Xr msgsnd 2 , 2780.Xr ntp_adjtime 2 , 2781.Xr ntp_gettime 2 , 2782.Xr semctl 2 , 2783.Xr semget 2 , 2784.Xr semop 2 , 2785.Xr shmat 2 , 2786.Xr shmctl 2 , 2787.Xr shmdt 2 , 2788.Xr shmget 2 , 2789.Xr sysctl 3 , 2790.Xr apm 4 , 2791.Xr ddb 4 , 2792.Xr inet 4 , 2793.Xr iso 4 , 2794.Xr lkm 4 , 2795.Xr md 4 , 2796.Xr ns 4 , 2797.Xr pcibios 4 , 2798.Xr pcmcia 4 , 2799.Xr ppp 4 , 2800.Xr userconf 4 , 2801.Xr vnd 4 , 2802.Xr wscons 4 , 2803.Xr config 5 , 2804.Xr edquota 8 , 2805.Xr init 8 , 2806.Xr mdsetimage 8 , 2807.Xr mount_cd9660 8 , 2808.Xr mount_fdesc 8 , 2809.Xr mount_kernfs 8 , 2810.Xr mount_lfs 8 , 2811.Xr mount_mfs 8 , 2812.Xr mount_msdos 8 , 2813.Xr mount_nfs 8 , 2814.Xr mount_ntfs 8 , 2815.Xr mount_null 8 , 2816.Xr mount_portal 8 , 2817.Xr mount_procfs 8 , 2818.Xr mount_udf 8 , 2819.Xr mount_umap 8 , 2820.Xr mount_union 8 , 2821.Xr mrouted 8 , 2822.Xr newfs_lfs 8 , 2823.Xr ntpd 8 , 2824.Xr quotaon 8 , 2825.Xr rpc.rquotad 8 , 2826.Xr sysctl 8 , 2827.Xr in_getifa 9 2828.Sh HISTORY 2829The 2830.Nm 2831man page first appeared in 2832.Nx 1.3 . 2833.Sh BUGS 2834The 2835.Em EON 2836option should be a pseudo-device, and is also very fragile. 2837