1.\" $NetBSD: options.4,v 1.461 2017/02/13 09:46:29 skrll Exp $ 2.\" 3.\" Copyright (c) 1996 4.\" Perry E. Metzger. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgment: 16.\" This product includes software developed for the NetBSD Project 17.\" by Perry E. Metzger. 18.\" 4. The name of the author may not be used to endorse or promote products 19.\" derived from this software without specific prior written permission. 20.\" 21.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 22.\" IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 23.\" OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 24.\" IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 25.\" INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 26.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 27.\" DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 28.\" THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 29.\" (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 30.\" THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 31.\" 32.\" 33.Dd January 8, 2017 34.Dt OPTIONS 4 35.Os 36.Sh NAME 37.Nm options 38.Nd Miscellaneous kernel configuration options 39.Sh SYNOPSIS 40.Cd cinclude ... 41.Cd config ... 42.Cd [no] file-system ... 43.Cd ident ... 44.Cd include ... 45.Cd [no] makeoptions ... 46.Cd maxusers ... 47.Cd [no] options ... 48.Cd [no] pseudo-device ... 49.Sh DESCRIPTION 50This manual page describes a number of miscellaneous kernel 51configuration options that may be specified in a kernel config 52file. 53See 54.Xr config 1 55and 56.Xr config 5 57for information on how to configure and build kernels. 58.Pp 59The 60.Ar no 61form removes a previously specified option. 62.Ss Keywords 63The following keywords are recognized in a kernel configuration file: 64.Bl -ohang 65.It Sy cinclude Qq Ar filename 66Conditionally includes another kernel configuration file whose name is 67.Ar filename , 68which may be double-quoted and may be an explicit path or relative to 69the kernel source directory. 70Failure to open the named file is ignored. 71.It Sy config Ar exec_name No root on Ar rootdev Oo type Ar fstype Oc \ 72Oo dumps on Ar dumpdev Oc 73Defines a configuration whose kernel executable is named 74.Ar exec_name , 75normally 76.Dq netbsd , 77with its root file system of type 78.Ar fstype 79on the device 80.Ar rootdev , 81and optionally specifying the location of kernel core dumps on the device 82.Ar dumpdev . 83.Ar dev 84or 85.Ar dumpdev 86and 87.Ar fstype 88may be specified as 89.Dq \&? , 90which is a wild card. 91The root 92.Ar fstype 93and 94.Ar dumpdev 95are optional and assumed to be wild carded if they are not specified. 96.It Ar device_instance No at Ar attachment \ 97Oo Ar locators value Oo ... Oc Oc Oo flags Ar value Oc 98Define an instance of the device driver 99.Ar device_instance 100that attaches to the bus or device named 101.Ar attachment . 102An 103.Ar attachment 104may require additional information on where the device can be found, such 105as an address, channel, function, offset, and/or slot, referred to as 106.Ar locators , 107whose 108.Ar value 109often may be a wild card, 110.Dq \&? . 111Some device drivers have one or more 112.Ar flags 113that can be adjusted to affect the way they operate. 114.It Sy file-system Ar fs_name Op , Ar fs_name Op ... 115Include support for the file-system 116.Ar fs_name . 117.It Sy ident Qq Ar string 118Sets the kernel identification string to 119.Ar string . 120.It Sy include Qq Ar filename 121Functions the same as 122.Ar cinclude , 123except failure to open 124.Ar filename 125produces a fatal error. 126.It Sy options Ar option_name Op , Ar option_name=value Op ... 127Specifies (or sets) the option, or comma-separated list of options, 128.Ar option_name . 129Some options expect to be assigned a value, which may be an integer, 130a double-quoted word, a bare word, or an empty string 131.Pq Qq . 132Note that those are eventually handled by the C compiler, so the rules 133of that language apply. 134.Pp 135.Em Note : 136Options that are not defined by device definition files are passed to 137the compile process as 138.Fl D 139flags to the C compiler. 140.It Sy makeoptions Ar name=value 141Defines a 142.Xr make 1 143macro 144.Ar name 145with the value 146.Ar value 147in the kernel Makefile. 148.It Sy maxusers Ar integer 149Set the maxusers variable in the kernel. 150.It Sy no Ar keyword Ar name Op Ar arguments Op ... 151For the 152.Xr config 1 153.Ar keywords 154file-system, makeoptions, options, and pseudo-device, 155.Ar no 156removes the file-system, makeoption, options, or pseudo-device, 157.Ar name . 158This is useful when a kernel configuration file includes another which 159has undesired options. 160.Pp 161For example, a local configuration file that wanted the kitchen sink, but 162not COMPAT_09 or bridging, might be: 163.Bd -literal -offset indent 164include "arch/i386/conf/GENERIC" 165no options COMPAT_09 166no pseudo-device bridge 167.Ed 168.It Sy pseudo-device Ar name Op Ar N 169Includes support for the pseudo-device 170.Ar name . 171Some pseudo-devices can have multiple or 172.Ar N 173instances. 174.El 175.Ss Compatibility Options 176.Bl -ohang 177.It Cd options COMPAT_09 178Enable binary compatibility with 179.Nx 0.9 . 180This enables support for 18116-bit user, group, and process IDs (following revisions support 18232-bit identifiers). 183It also allows the use of the deprecated 184.Xr getdomainname 3 , 185.Xr setdomainname 3 , 186and 187.Xr uname 3 188syscalls. 189This option also allows using numeric file system identifiers rather 190than strings. 191Post 192.Nx 0.9 193versions use string identifiers. 194.It Cd options COMPAT_10 195Enable binary compatibility with 196.Nx 1.0 . 197This option allows the use of the file system name of 198.Dq ufs 199as an alias for 200.Dq ffs . 201The name 202.Dq ffs 203should be used post 1.0 in 204.Pa /etc/fstab 205and other files. 206It also adds old syscalls for the 207.At V 208shared memory interface. 209This was changed post 1.0 to work on 64-bit architectures. 210This option also enables 211.Dq sgtty 212compatibility, without which programs using the old interface produce 213an 214.Dq inappropriate ioctl 215error, and 216.Pa /dev/io 217only works when this option is set in the kernel, 218see 219.Xr io 4 220on ports that support it. 221.It Cd options COMPAT_11 222Enable binary compatibility with 223.Nx 1.1 . 224This allows binaries running on the i386 port to gain direct access to 225the io ports by opening 226.Pa /dev/io 227read/write. 228This functionality was replaced by 229.Xr i386_iopl 2 230post 1.1. 231On the 232.Tn Atari 233port, the location of the disk label was moved after 1.1. 234When the 235.Em COMPAT_11 236option is set, the kernel will read (pre) 1.1 style disk labels as a 237last resort. 238When a disk label is re-written, the old style label will be replaced 239with a post 1.1 style label. 240This also enables the 241.Em EXEC_ELF_NOTELESS 242option. 243.It Cd options COMPAT_12 244Enable binary compatibility with 245.Nx 1.2 . 246This allows the use of old syscalls for 247.Fn reboot 248and 249.Fn swapon . 250The syscall numbers were changed post 1.2 to add functionality to the 251.Xr reboot 2 252syscall, and the new 253.Xr swapctl 2 254interface was introduced. 255This also enables the 256.Em EXEC_ELF_NOTELESS 257option. 258.It Cd options COMPAT_13 259Enable binary compatibility with 260.Nx 1.3 . 261This allows the use of old syscalls for 262.Fn sigaltstack , 263and also enables the old 264.Xr swapctl 2 265command 266.Dv SWAP_STATS 267(now called 268.Dv SWAP_OSTATS ) , 269which does not include the 270.Fa se_path 271member of 272.Va struct swapent . 273.It Cd options COMPAT_14 274Enable binary compatibility with 275.Nx 1.4 . 276This allows some old 277.Xr ioctl 2 278on 279.Xr wscons 4 280to be performed, and allows the 281.Dv NFSSVC_BIOD 282mode of the 283.Xr nfssvc 2 284system call to be used for compatibility with the deprecated nfsiod program. 285.It Cd options COMPAT_15 286Enable binary compatibility with 287.Nx 1.5 . 288Since there were no API changes from 289.Nx 1.5 290and 291.Nx 1.6 , 292this option does nothing. 293.It Cd options COMPAT_16 294Enable binary compatibility with 295.Nx 1.6 . 296This allows the use of old signal trampoline code which has been deprecated 297with the addition of 298.Xr siginfo 2 . 299.It Cd options COMPAT_20 300Enable binary compatibility with 301.Nx 2.0 . 302This allows the use of old syscalls for 303.Fn statfs , 304.Fn fstatfs , 305.Fn getfsstat 306and 307.Fn fhstatfs , 308which have been deprecated with the addition of the 309.Xr statvfs 2 , 310.Xr fstatvfs 2 , 311.Xr getvfsstat 2 312and 313.Xr fhstatvfs 2 314system calls. 315.It Cd options COMPAT_30 316Enable binary compatibility with 317.Nx 3.0 . 318See 319.Xr compat_30 8 320for details about the changes made after the 321.Nx 3.0 322release. 323.It Cd options COMPAT_40 324Enable binary compatibility with 325.Nx 4.0 . 326.It Cd options COMPAT_43 327Enables compatibility with 328.Bx 4.3 . 329This adds an old syscall for 330.Xr lseek 2 . 331It also adds the ioctls for 332.Dv TIOCGETP 333and 334.Dv TIOCSETP . 335The return values for 336.Xr getpid 2 , 337.Xr getgid 2 , 338and 339.Xr getuid 2 340syscalls are modified as well, to return the parent's PID and 341UID as well as the current process's. 342It also enables the deprecated 343.Dv NTTYDISC 344terminal line discipline. 345It also provides backwards compatibility with 346.Dq old 347SIOC[GS]IF{ADDR,DSTADDR,BRDADDR,NETMASK} interface ioctls, including 348binary compatibility with code written before the introduction of the 349sa_len field in sockaddrs. 350It also enables 351support for some older pre 352.Bx 4.4 353socket calls. 354.It Cd options COMPAT_50 355Enable binary compatibility with 356.Nx 5.0 . 357.It Cd options COMPAT_60 358Enable binary compatibility with 359.Nx 6.0 . 360.It Cd options COMPAT_70 361Enable binary compatibility with 362.Nx 7.0 . 363.It Cd options COMPAT_BSDPTY 364This option is currently on by default and enables the pty multiplexer 365.Xr ptm 4 366and 367.Xr ptmx 4 368to find and use ptys named 369.Pa /dev/ptyXX 370(master) and 371.Pa /dev/ttyXX 372(slave). 373Eventually this option will become optional as ptyfs based pseudo-ttys become 374the default, see 375.Xr mount_ptyfs 8 . 376.It Cd options COMPAT_SVR4 377On those architectures that support it, this enables binary 378compatibility with 379.At V.4 380applications built for the same architecture. 381This currently includes the i386, m68k, and sparc ports. 382.It Cd options COMPAT_LINUX 383On those architectures that support it, this enables binary 384compatibility with Linux ELF and 385.Xr a.out 5 386applications built for the same architecture. 387This currently includes the alpha, arm, i386, m68k, mips, powerpc and 388x86_64 ports. 389.It Cd options COMPAT_LINUX32 390On those 64 bit architectures that support it, this enables binary 391compatibility with 32 bit Linux binaries. 392For now this is limited to running i386 ELF Linux binaries on amd64. 393.It Cd options COMPAT_SUNOS 394On those architectures that support it, this enables binary 395compatibility with 396.Tn SunOS 4.1 397applications built for the same architecture. 398This currently includes the sparc, sparc64 and most or all m68k ports. 399Note that the sparc64 requires the 400.Em COMPAT_NETBSD32 401option for 64-bit kernels, in addition to this option. 402.It Cd options COMPAT_ULTRIX 403On those architectures that support it, this enables binary 404compatibility with 405.Tn ULTRIX 406applications built for the same architecture. 407This currently is limited to the pmax. 408The functionality of this option is unknown. 409.It Cd options COMPAT_FREEBSD 410On those architectures that support it, this enables binary 411compatibility with 412.Fx 413applications built for the same architecture. 414At the moment this is limited to the i386 port. 415.It Cd options COMPAT_IBCS2 416On those architectures that support it, this enables binary 417compatibility with iBCS2 or SVR3 applications built for the same architecture. 418This is currently limited to the i386 and vax ports. 419.It Cd options COMPAT_OSF1 420On those architectures that support it, this enables binary 421compatibility with 422.Tn Digital 423.Ux 424.Po 425formerly 426.Tn OSF/1 427.Pc 428applications built for the same architecture. 429This is currently limited to the alpha port. 430.It Cd options COMPAT_NOMID 431Enable compatibility with 432.Xr a.out 5 433executables that lack a machine ID. 434This includes 435.Nx 0.8 Ns 's 436ZMAGIC format, and 386BSD and BSDI's 437QMAGIC, NMAGIC, and OMAGIC 438.Xr a.out 5 439formats. 440.It Cd options COMPAT_NETBSD32 441On those architectures that support it, this enables binary 442compatibility with 32-bit applications built for the same architecture. 443This is currently limited to the amd64 and sparc64 ports, and only 444applicable for 64-bit kernels. 445.It Cd options COMPAT_SVR4_32 446On those architectures that support it, this enables binary 447compatibility with 32-bit SVR4 applications built for the same architecture. 448This is currently limited to the sparc64 port, and only applicable for 44964-bit kernels. 450.It Cd options COMPAT_AOUT_M68K 451On m68k architectures which have switched to ELF, 452this enables binary compatibility with 453.Nx Ns Tn /m68k 454.Xr a.out 5 455executables on 456.Nx Ns Tn /m68k 457ELF kernels. 458This handles alignment incompatibility of m68k ABI between 459a.out and ELF which causes the structure padding differences. 460Currently only some system calls which use 461.Va struct stat 462are adjusted and some binaries which use 463.Xr sysctl 3 464to retrieve network details would not work properly. 465.It Cd options EMUL_NATIVEROOT=string 466Just like emulated binaries first try looking up files in 467an emulation root (e.g. 468.Pa /emul/linux ) 469before looking them up in real root, this option causes native 470binaries to first look up files in an "emulation" directory too. 471This can be useful to test an amd64 kernel on top of an i386 system 472before full migration: by unpacking the amd64 distribution in e.g. 473.Pa /emul/netbsd64 474and specifying that location as 475.Cd EMUL_NATIVEROOT , 476native amd64 binaries can be run while the root file system remains 477populated with i386 binaries. 478Beware of 479.Pa /dev 480incompatibilities between i386 and amd64 if you do this. 481.It Cd options EXEC_ELF_NOTELESS 482Run unidentified ELF binaries as 483.Nx 484binaries. 485This might be needed for very old 486.Nx 487ELF binaries on some archs. 488These old binaries didn't contain an appropriate 489.Li .note.netbsd.ident 490section, and thus can't be identified by the kernel as 491.Nx 492binaries otherwise. 493Beware - if this option is on, the kernel would run 494.Em any 495unknown ELF binaries as if they were 496.Nx 497binaries. 498.El 499.Ss Debugging Options 500.Bl -ohang 501.It Cd options DDB 502Compiles in a kernel debugger for diagnosing kernel problems. 503See 504.Xr ddb 4 505for details. 506.Em NOTE : 507not available on all architectures. 508.It Cd options DDB_FROMCONSOLE=integer 509If set to non-zero, DDB may be entered by sending a break on a serial 510console or by a special key sequence on a graphics console. 511A value of "0" ignores console breaks or key sequences. 512If not explicitly specified, the default value is "1". 513Note that this sets the value of the 514.Em ddb.fromconsole 515.Xr sysctl 3 516variable which may be changed at run time -- see 517.Xr sysctl 8 518for details. 519.It Cd options DDB_HISTORY_SIZE=integer 520If this is non-zero, enable history editing in the kernel debugger 521and set the size of the history to this value. 522.It Cd options DDB_ONPANIC 523The default if not specified is 524.Dq 1 525- just enter into DDB. 526If set to 527.Dq 2 528the kernel will 529attempt to print out a stack trace before entering into DDB. 530If set to 531.Dq 0 532the kernel will attempt to print out a stack trace 533and reboot the system. 534If set to 535.Dq -1 536then neither a stack trace is printed or DDB entered - 537it is as if DDB were not compiled into the kernel. 538Note that this sets the value of the 539.Em ddb.onpanic 540.Xr sysctl 3 541variable which may be changed at run time -- see 542.Xr sysctl 8 543for details. 544.It Cd options DDB_COMMANDONENTER=string 545This option specify commands which will be executed on each entry to DDB. 546This sets the default value of the 547.Em ddb.commandonenter 548.Xr sysctl 3 549variable which may be changed at run time. 550.It Cd options DDB_BREAK_CHAR=integer 551This option overrides using break to enter the kernel debugger 552on the serial console. 553The value given is the ASCII value to be used instead. 554This is currently only supported by the com driver. 555.It Cd options DDB_VERBOSE_HELP 556This option adds more verbose descriptions to the 557.Em help 558command. 559.It Cd options KGDB 560Compiles in a remote kernel debugger stub for diagnosing kernel problems 561using the 562.Dq remote target 563feature of gdb. 564See 565.Xr gdb 1 566for details. 567.Em NOTE : 568not available on all architectures. 569.It Cd options KGDB_DEV 570Device number 571.Po 572as a 573.Dv dev_t 574.Pc 575of kgdb device. 576.It Cd options KGDB_DEVADDR 577Memory address of kgdb device. 578.It Cd options KGDB_DEVMODE 579Permissions of kgdb device. 580.It Cd options KGDB_DEVNAME 581Device name of kgdb device. 582.It Cd options KGDB_DEVRATE 583Baud rate of kgdb device. 584.It Cd makeoptions DEBUG="-g" 585The 586.Fl g 587flag causes 588.Pa netbsd.gdb 589to be built in addition to 590.Pa netbsd . 591.Pa netbsd.gdb 592is useful for debugging kernel crash dumps with gdb. 593See 594.Xr gdb 1 595for details. 596This also turns on 597.Em options DEBUG 598(which see). 599.It Cd options DEBUG 600Turns on miscellaneous kernel debugging. 601Since options are turned into preprocessor defines (see above), 602.Em options DEBUG 603is equivalent to doing a 604.Em #define DEBUG 605throughout the kernel. 606Much of the kernel has 607.Em #ifdef DEBUG 608conditionalized debugging code. 609Note that many parts of the kernel (typically device drivers) include their own 610.Em #ifdef XXX_DEBUG 611conditionals instead. 612This option also turns on certain other options, 613which may decrease system performance. 614Systems with this option are not suitable for regular use, and are 615intended only for debugging or looking for bugs. 616.It Cd options DIAGNOSTIC 617Adds code to the kernel that does internal consistency checks. 618This code will cause the kernel to panic if corruption of internal data 619structures is detected. 620Historically, the performance degradation is sufficiently small that 621it is reasonable for systems with 622.Em options DIAGNOSTIC 623to be in production use, with the real consideration not being 624performance but instead a preference for more panics versus continued 625operation with undetected problems. 626.It Cd options LOCKDEBUG 627Adds code to the kernel to detect incorrect use of locking primitives 628(mutex, rwlock). 629This code will cause the kernel to check for dead lock conditions. 630It will also check for memory being freed to not contain initialised 631lock primitives. 632Functions for use in 633.Xr ddb 4 634to check lock chains etc. are also enabled. 635These checks are very expensive and can decrease performance on 636multi-processor machines by a factor of three. 637.It Cd options KSTACK_CHECK_MAGIC 638Check kernel stack usage and panic if stack overflow is detected. 639This check is performance sensitive because it scans stack on each context 640switch. 641.It Cd options KTRACE 642Add hooks for the system call tracing facility, which allows users to 643watch the system call invocation behavior of processes. 644See 645.Xr ktrace 1 646for details. 647.It Cd options MSGBUFSIZE=integer 648This option sets the size of the kernel message buffer. 649This buffer holds the kernel output of 650.Fn printf 651when not (yet) read by 652.Xr syslogd 8 . 653This is particularly useful when the system has crashed and you wish to lookup 654the kernel output from just before the crash. 655Also, since the autoconfig output becomes more and more verbose, 656it sometimes happens that the message buffer overflows before 657.Xr syslogd 8 658was able to read it. 659Note that not all systems are capable of obtaining a variable sized message 660buffer. 661There are also some systems on which memory contents are not preserved 662across reboots. 663.It Cd options KERNHIST 664Enables the kernel history logs, which create in-memory traces of 665various kernel activities. 666These logs can be displayed by using 667.Cm show kernhist 668from DDB. 669See the kernel source file 670.Pa sys/kern/kern_history.c 671and the 672.Xr kernhist 9 673manual for details. 674.It Cd options KERNHIST_PRINT 675Prints the kernel history logs on the system console as entries are added. 676Note that the output is 677.Em extremely 678voluminous, so this option is really only useful for debugging 679the very earliest parts of kernel initialization. 680.It Cd options UVMHIST 681Like 682.Em KERNHIST , 683it enables the UVM history logs. 684These logs can be displayed by using 685.Cm show kernhist 686from DDB. 687See the kernel source file 688.Pa sys/uvm/uvm_stat.c 689for details. 690.It Cd options UVMHIST_PRINT 691Like 692.Em UVMHIST , 693it prints the UVM history logs on the system console as entries are added. 694Note that the output is 695.Em extremely 696voluminous, so this option is really only useful for debugging 697the very earliest parts of kernel initialization. 698.It Cd options UVMHIST_MAPHIST_SIZE 699Set the size of the 700.Dq maphist 701kernel history. 702The default is 100. 703This option depends upon the 704.Em UVMHIST 705option. 706.It Cd options UVMHIST_PDHIST_SIZE 707Set the size of the 708.Dq pdhist 709kernel history. 710The default is 100. 711This option depends upon the 712.Em UVMHIST 713option. 714.It Cd options BIOHIST 715Like 716.Em KERNHIST , 717it enables the BIO history logs. 718These logs can be displayed by using 719.Cm show kernhist 720from DDB, and can help in debugging problems with Buffered I/O operations. 721See the kernel source file 722.Pa sys/kern/vfs_vio.c 723for details. 724.It Cd options BIOHIST_PRINT 725Like 726.Em BIOHIST , 727it prints the BIO history logs on the system console as entries are added. 728Note that the output is 729.Em extremely 730voluminous, so this option is really only useful for debugging 731the very earliest parts of kernel initialization. 732.It Cd options BIOHIST_SIZE 733Set the size of the 734.Dq biohist 735kernel history. 736The default is 500. 737This option depends upon the 738.Em BIOHIST 739option. 740.El 741.Ss File Systems 742.Bl -ohang 743.It Cd file-system FFS 744Includes code implementing the Berkeley Fast File System 745.Po Em FFS Pc . 746Most machines need this if they are not running diskless. 747.It Cd file-system EXT2FS 748Includes code implementing the Second Extended File System 749.Po Em ext2 Pc , 750revision 0 and revision 1 with the 751.Em filetype , 752.Em sparse_super 753and 754.Em large_file 755options. 756This is the most commonly used file system on the Linux operating system, 757and is provided here for compatibility. 758Some of the specific features of 759.Em ext2 760like the "behavior on errors" are not implemented. 761See 762.Xr mount_ext2fs 8 763for details. 764.It Cd file-system LFS 765.Bq Em EXPERIMENTAL 766Include the Log-structured File System 767.Po Em LFS Pc . 768See 769.Xr mount_lfs 8 770and 771.Xr newfs_lfs 8 772for details. 773.It Cd file-system MFS 774Include the Memory File System 775.Po Em MFS Pc . 776This file system stores files in swappable memory, and produces 777notable performance improvements when it is used as the file store 778for 779.Pa /tmp 780and similar file systems. 781See 782.Xr mount_mfs 8 783for details. 784.It Cd file-system NFS 785Include the client side of the Network File System 786.Pq Tn NFS 787remote file sharing protocol. 788Although the bulk of the code implementing 789.Tn NFS 790is kernel based, several user level daemons are needed for it to work. 791See 792.Xr mount_nfs 8 793for details. 794.It Cd file-system CD9660 795Includes code for the 796.Tn ISO 7979660 + Rock Ridge file system, which is the standard file system on many 798.Tn CD-ROM 799discs. 800Useful primarily if you have a 801.Tn CD-ROM 802drive. 803See 804.Xr mount_cd9660 8 805for details. 806.It Cd file-system MSDOSFS 807Includes the 808.Tn MS-DOS 809FAT file system, which is reportedly still used 810by unfortunate people who have not heard about 811.Nx . 812Also implements the 813.Tn Windows 95 814extensions to the same, which permit the use of longer, mixed case 815file names. 816See 817.Xr mount_msdos 8 818and 819.Xr fsck_msdos 8 820for details. 821.It Cd file-system NTFS 822.Bq Em EXPERIMENTAL 823Includes code for the 824.Tn Microsoft Windows NT 825file system. 826See 827.Xr mount_ntfs 8 828for details. 829.It Cd file-system FDESC 830Includes code for a file system, conventionally mounted on 831.Pa /dev/fd , 832which permits access to the per-process file descriptor space via 833special files in the file system. 834See 835.Xr mount_fdesc 8 836for details. 837Note that this facility is redundant, and thus unneeded on most 838.Nx 839systems, since the 840.Xr fd 4 841pseudo-device driver already provides identical functionality. 842On most 843.Nx 844systems, instances of 845.Xr fd 4 846are mknoded under 847.Pa /dev/fd/ 848and on 849.Pa /dev/stdin , 850.Pa /dev/stdout , 851and 852.Pa /dev/stderr . 853.It Cd file-system KERNFS 854Includes code which permits the mounting of a special file system 855(normally mounted on 856.Pa /kern ) 857in which files representing various kernel variables and parameters 858may be found. 859See 860.Xr mount_kernfs 8 861for details. 862.It Cd file-system NULLFS 863Includes code for a loopback file system. 864This permits portions of the file hierarchy to be re-mounted in other places. 865The code really exists to provide an example of a stackable file system layer. 866See 867.Xr mount_null 8 868for details. 869.It Cd file-system OVERLAY 870Includes code for a file system filter. 871This permits the overlay file system to intercept all access to an underlying 872file system. 873This file system is intended to serve as an example of a stacking file 874system which has a need to interpose itself between an underlying file 875system and all other access. 876See 877.Xr mount_overlay 8 878for details. 879.It Cd file-system PROCFS 880Includes code for a special file system (conventionally mounted on 881.Pa /proc ) 882in which the process space becomes visible in the file system. 883Among 884other things, the memory spaces of processes running on the system are 885visible as files, and signals may be sent to processes by writing to 886.Pa ctl 887files in the procfs namespace. 888See 889.Xr mount_procfs 8 890for details. 891.It Cd file-system UDF 892.Bq Em EXPERIMENTAL 893Includes code for the UDF file system commonly found on CD and DVD 894media but also on USB sticks. 895Currently supports read and write access upto UDF 2.01 and somewhat limited 896write support for UDF 2.50. 897It is marked experimental since there is no 898.Xr fsck_udf 8 . 899See 900.Xr mount_udf 8 901for details. 902.It Cd file-system UMAPFS 903Includes a loopback file system in which user and group IDs may be 904remapped -- this can be useful when mounting alien file systems with 905different UIDs and GIDs than the local system. 906See 907.Xr mount_umap 8 908for details. 909.It Cd file-system UNION 910.Bq Em EXPERIMENTAL 911Includes code for the union file system, which permits directories to 912be mounted on top of each other in such a way that both file systems 913remain visible -- this permits tricks like allowing writing (and the 914deleting of files) on a read-only file system like a 915.Tn CD-ROM 916by mounting a local writable file system on top of the read-only file system. 917See 918.Xr mount_union 8 919for details. 920.It Cd file-system CODA 921.Bq Em EXPERIMENTAL 922Includes code for the Coda file system. 923Coda is a distributed file system like NFS and AFS. 924It is freely available, like NFS, but it functions much like AFS in being a 925.Dq stateful 926file system. 927Both Coda and AFS cache files on your local machine to improve performance. 928Then Coda goes a step further than AFS by letting you access the cached 929files when there is no available network, viz. disconnected laptops and 930network outages. 931In Coda, both the client and server are outside the kernel which makes 932them easier to experiment with. 933Coda is available for several UNIX and non-UNIX platforms. 934See 935.Lk http://www.coda.cs.cmu.edu 936for more details. 937.Em NOTE : 938You also need to enable the pseudo-device, vcoda, for the Coda 939file system to work. 940.It Cd file-system SMBFS 941.Bq Em EXPERIMENTAL 942Includes code for the SMB/CIFS file system. 943See 944.Xr mount_smbfs 8 945for details. 946.Em NOTE : 947You also need to enable the pseudo-device, nsmb, for the SMB 948file system to work. 949.It Cd file-system PTYFS 950.Bq Em EXPERIMENTAL 951Includes code for a special file system (normally mounted on 952.Pa /dev/pts ) 953in which pseudo-terminal slave devices become visible in the file system. 954See 955.Xr mount_ptyfs 8 956for details. 957.It Cd file-system TMPFS 958Includes code for the efficient memory file system, normally used over 959.Pa /tmp . 960See 961.Xr mount_tmpfs 8 962for details. 963.It Cd file-system PUFFS 964Includes kernel support for the pass-to-userspace framework file system. 965It can be used to implement file system functionality in userspace. 966See 967.Xr puffs 3 968for more details. 969This enables for example sshfs: 970.Xr mount_psshfs 8 . 971.El 972.Ss File System Options 973.Bl -ohang 974.It Cd options MAGICLINKS 975Enables the expansion of special strings 976.Po 977beginning with 978.Dq @ 979.Pc 980when traversing symbolic links. 981See 982.Xr symlink 7 983for a list of supported strings. 984Note that this option only controls the enabling of this feature 985by the kernel at boot-up. 986This feature can still be manipulated with the 987.Xr sysctl 8 988command regardless of the setting of this option. 989.It Cd options NFSSERVER 990Include the server side of the 991.Em NFS 992(Network File System) remote file sharing protocol. 993Although the bulk of the code implementing 994.Em NFS 995is kernel based, several user level daemons are needed for it to 996work. 997See 998.Xr mountd 8 999and 1000.Xr nfsd 8 1001for details. 1002.It Cd options NVNODE=integer 1003This option sets the size of the cache used by the name-to-inode translation 1004routines, (a.k.a. the 1005.Fn namei 1006cache, though called by many other names in the kernel source). 1007By default, this cache has 1008.Dv (NPROC + NTEXT + 100) 1009entries (NPROC set as 20 + 16 * MAXUSERS and NTEXT as 80 + NPROC / 8). 1010A reasonable way to derive a value of 1011.Dv NVNODE , 1012should you notice a large number of namei cache misses with a tool such as 1013.Xr systat 1 , 1014is to examine your system's current computed value with 1015.Xr sysctl 8 , 1016(which calls this parameter "kern.maxvnodes") and to increase this value 1017until either the namei cache hit rate improves or it is determined that 1018your system does not benefit substantially from an increase in the size of 1019the namei cache. 1020.It Cd options NAMECACHE_ENTER_REVERSE 1021Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 1022as well as a normal one. 1023Normally, this is already done for directory vnodes, to speed up the getcwd 1024operation. 1025This option will cause longer hash chains in the reverse cache, and thus 1026slow down getcwd somewhat. 1027However, it does make vnode -\*[Gt] path translations possible in some cases. 1028For now, only useful if strict 1029.Pa /proc/#/maps 1030emulation for Linux binaries is required. 1031.El 1032.Ss Options for FFS/UFS File Systems 1033.Bl -ohang 1034.It Cd options WAPBL 1035Enable 1036.Dq Write Ahead Physical Block Logging file system journaling . 1037This provides rapid file system consistency checking after a system outage. 1038It also provides better general use performance over regular FFS. 1039See also 1040.Xr wapbl 4 . 1041.It Cd options QUOTA 1042Enables kernel support for traditional quotas in FFS. 1043Traditional quotas store the quota information in external files and 1044require 1045.Xr quotacheck 8 1046and 1047.Xr quotaon 8 1048at boot time. 1049Traditional quotas are limited to 32-bit sizes and are at this point 1050considered a legacy feature. 1051.It Cd options QUOTA2 1052Enables kernel support for in-volume quotas in FFS. 1053The quota information is file system metadata maintained by 1054.Xr fsck 8 1055and/or WAPBL journaling. 1056MFS volumes can also use 1057.Dv QUOTA2 1058quotas; see 1059.Xr mount_mfs 8 1060for more information. 1061.It Cd options FFS_EI 1062Enable 1063.Dq Endian-Independent 1064FFS support. 1065This allows a system to mount an FFS file system created for another 1066architecture, at a small performance cost for all FFS file systems. 1067See also 1068.Xr newfs 8 , 1069.Xr fsck_ffs 8 , 1070.Xr dumpfs 8 1071for file system byte order status and manipulation. 1072.It Cd options FFS_NO_SNAPSHOT 1073Disable support for the creation of file system internal snapshot 1074of FFS file systems. 1075Maybe useful for install media kernels, small memory systems and 1076embedded systems which don't require the snapshot support. 1077.It Cd options UFS_EXTATTR 1078Enable extended attribute support for UFS1 file systems. 1079.It Cd options UFS_DIRHASH 1080Increase lookup performance by maintaining in-core hash tables 1081for large directories. 1082.El 1083.Ss Options for the LFS File System 1084.Bl -ohang 1085.\" .It Cd options LFS_KERNEL_RFW 1086.\" There is no documentation for this. (XXX) 1087.\" .It Cd options LFS_QUOTA 1088.\" Enable traditional quota support for LFS. 1089.\" (It is not clear if this works.) 1090.\" .It Cd options LFS_QUOTA2 1091.\" Enable modernized 64-bit quota support for LFS. 1092.\" (This does not work yet.) 1093.It Cd options LFS_EI 1094Enable 1095.Dq Endian-Independent 1096LFS support. 1097This allows (at a small performance cost) mounting an LFS file system 1098created for another architecture. 1099.\" .It Cd options LFS_EXTATTR 1100.\" Enable extended attribute support for LFS. 1101.\" (It is not clear if this works.) 1102.It Cd options LFS_DIRHASH 1103Increase lookup performance by maintaining in-core hash tables 1104for large directories. 1105.El 1106.Ss Options for the ext2fs File System 1107.Bl -ohang 1108.It Cd options EXT2FS_SYSTEM_FLAGS 1109This option changes the behavior of the APPEND and IMMUTABLE flags 1110for a file on an 1111.Em ext2 1112file system. 1113Without this option, the superuser or owner of the file can 1114set and clear them. 1115With this option, only the superuser can set them, and 1116they can't be cleared if the securelevel is greater than 0. 1117See also 1118.Xr chflags 1 1119and 1120.Xr secmodel_securelevel 9 . 1121.El 1122.Ss Options for the NFS File System 1123.Bl -ohang 1124.It Cd options NFS_BOOT_BOOTP 1125Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1126information if NFS is used to mount the root file system. 1127See 1128.Xr diskless 8 1129for details. 1130.It Cd options NFS_BOOT_BOOTSTATIC 1131Enable use of static values defined as 1132.Dq NFS_BOOTSTATIC_MYIP , 1133.Dq NFS_BOOTSTATIC_GWIP , 1134.Dq NFS_BOOTSTATIC_SERVADDR , 1135and 1136.Dq NFS_BOOTSTATIC_SERVER 1137in kernel options to get configuration information 1138if NFS is used to mount the root file system. 1139.It Cd options NFS_BOOT_DHCP 1140Same as 1141.Dq NFS_BOOT_BOOTP , 1142but use the DHCP extensions to the 1143BOOTP protocol (RFC 1541). 1144.It Cd options NFS_BOOT_BOOTP_REQFILE 1145Specifies the string sent in the bp_file field of the BOOTP/DHCP 1146request packet. 1147.It Cd options NFS_BOOT_BOOTPARAM 1148Enable use of the BOOTPARAM protocol, consisting of RARP and 1149BOOTPARAM RPC, to get configuration information if NFS 1150is used to mount the root file system. 1151See 1152.Xr diskless 8 1153for details. 1154.It Cd options NFS_BOOT_RWSIZE=value 1155Set the initial NFS read and write sizes for diskless-boot requests. 1156The normal default is 8Kbytes. 1157This option provides a way to lower the value (e.g., to 1024 bytes) 1158as a workaround for buggy network interface cards or boot PROMs. 1159Once booted, the read and write request sizes can be increased by 1160remounting the file system. 1161See 1162.Xr mount_nfs 8 1163for details. 1164.It Cd options NFS_V2_ONLY 1165Reduce the size of the NFS client code by omitting code that's only required 1166for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1167servers. 1168.It Cd options NFS_BOOT_TCP 1169Use NFS over TCP instead of the default UDP, for mounting root. 1170.El 1171.Ss Buffer queue strategy options 1172The following options enable alternative buffer queue strategies. 1173.Bl -ohang 1174.It Cd options BUFQ_READPRIO 1175Enable experimental buffer queue strategy for disk I/O. 1176In the default strategy, outstanding disk requests are ordered by 1177sector number and sent to the disk, regardless of whether the 1178operation is a read or write; this option gives priority to issuing 1179read requests over write requests. 1180Although requests may therefore be issued out of sector-order, causing 1181more seeks and thus lower overall throughput, interactive system 1182responsiveness under heavy disk I/O load may be improved, as processes 1183blocking on disk reads are serviced sooner (file writes typically 1184don't cause applications to block). 1185The performance effect varies greatly depending on the hardware, drive 1186firmware, file system configuration, workload, and desired performance 1187trade-off. 1188Systems using drive write-cache (most modern IDE disks, by default) 1189are unlikely to benefit and may well suffer; such disks acknowledge 1190writes very quickly, and optimize them internally according to 1191physical layout. 1192Giving these disks as many requests to work with as possible (the 1193standard strategy) will typically produce the best results, especially 1194if the drive has a large cache; the drive will silently complete 1195writes from cache as it seeks for reads. 1196Disks that support a large number of concurrent tagged requests (SCSI 1197disks and many hardware RAID controllers) expose this internal 1198scheduling with tagged responses, and don't block for reads; such 1199disks may not see a noticeable difference with either strategy. 1200However, if IDE disks are run with write-cache disabled for safety, 1201writes are not acknowledged until actually completed, and only one 1202request can be outstanding; a large number of small writes in one 1203locality can keep the disk busy, starving reads elsewhere on the disk. 1204Such systems are likely to see the most benefit from this option. 1205Finally, the performance interaction of this option with ffs soft 1206dependencies can be subtle, as that mechanism can drastically alter 1207the workload for file system metadata writes. 1208.It Cd options BUFQ_PRIOCSCAN 1209Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1210.It Cd options NEW_BUFQ_STRATEGY 1211Synonym of 1212.Em BUFQ_READPRIO . 1213.El 1214.Ss Miscellaneous Options 1215.Bl -ohang 1216.It Cd options CPU_UCODE 1217Support cpu microcode loading via 1218.Xr cpuctl 8 . 1219.It Cd options MEMORY_DISK_DYNAMIC 1220This option makes the 1221.Xr md 4 1222.Tn RAM 1223disk size dynamically sized. 1224It is incompatible with 1225.Xr mdsetimage 8 . 1226.It Cd options MEMORY_DISK_HOOKS 1227This option allows for some machine dependent functions to be called when 1228the 1229.Xr md 4 1230.Tn RAM 1231disk driver is configured. 1232This can result in automatically loading a 1233.Tn RAM 1234disk from floppy on open (among other things). 1235.It Cd options MEMORY_DISK_IS_ROOT 1236Forces the 1237.Xr md 4 1238.Tn RAM 1239disk to be the root device. 1240This can only be overridden when 1241the kernel is booted in the 'ask-for-root' mode. 1242.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1243Allocates the given number of 512 byte blocks as memory for the 1244.Xr md 4 1245.Tn RAM 1246disk, to be populated with 1247.Xr mdsetimage 8 . 1248.It Cd options MEMORY_DISK_SERVER=0 1249Do not include the interface to a userland memory disk server process. 1250Per default, this option is set to 1, including the support code. 1251Useful for install media kernels. 1252.It Cd options MEMORY_DISK_RBFLAGS=value 1253This option sets the 1254.Xr reboot 2 1255flags used when booting with a memory disk as root file system. 1256Possible values include 1257.Dv RB_AUTOBOOT 1258(boot in the usual fashion - default value), and 1259.Dv RB_SINGLE 1260(boot in single-user mode). 1261.It Cd options MODULAR 1262Enables the framework for kernel modules (see 1263.Xr module 7 ) . 1264.It Cd options MODULAR_DEFAULT_AUTOLOAD 1265Enables the autoloading of kernel modules by default. 1266This sets the default value of the 1267.Em kern.module.autoload 1268.Xr sysctl 3 1269variable which may be changed at run time. 1270.It Cd options VND_COMPRESSION 1271Enables the 1272.Xr vnd 4 1273driver to also handle compressed images. 1274See 1275.Xr vndcompress 1 , 1276.Xr vnd 4 1277and 1278.Xr vnconfig 8 1279for more information. 1280.It Cd options SPLDEBUG 1281Help the kernel programmer find bugs related to the interrupt priority 1282level. 1283When 1284.Fn spllower 1285or 1286.Fn splraise 1287changes the current CPU's interrupt priority level to or from 1288.Dv IPL_HIGH , 1289record a backtrace. 1290Read 1291.Xr return_address 9 1292for caveats about collecting backtraces. 1293This feature is experimental, and it is only available on i386. 1294See 1295.Pa sys/kern/subr_spldebug.c . 1296.It Cd options TFTPROOT 1297Download the root memory disk through TFTP at root mount time. 1298This enables the use of a root 1299.Tn RAM 1300disk without requiring it to be embedded in the kernel using 1301.Xr mdsetimage 8 . 1302The 1303.Tn RAM 1304disk name is obtained using DHCP's filename parameter. 1305This option requires 1306.Em MEMORY_DISK_HOOKS , 1307.Em MEMORY_DISK_DYNAMIC , 1308and 1309.Em MEMORY_DISK_IS_ROOT . 1310It is incompatible with 1311.Em MEMORY_DISK_ROOT_SIZE . 1312.It Cd options HZ=integer 1313On ports that support it, set the system clock frequency (see 1314.Xr hz 9 ) 1315to the supplied value. 1316Handle with care. 1317.It Cd options NTP 1318Turns on in-kernel precision timekeeping support used by software 1319implementing 1320.Em NTP 1321(Network Time Protocol, RFC 1305). 1322The 1323.Em NTP 1324option adds an in-kernel Phase-Locked Loop (PLL) for normal 1325.Em NTP 1326operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1327operation. 1328.Xr ntpd 8 1329will employ a user-level PLL when kernel support is unavailable, 1330but the in-kernel version has lower latency and more precision, and 1331so typically keeps much better time. 1332.Pp 1333The interface to the kernel 1334.Em NTP 1335support is provided by the 1336.Xr ntp_adjtime 2 1337and 1338.Xr ntp_gettime 2 1339system calls, which are intended for use by 1340.Xr ntpd 8 1341and are enabled by the option. 1342On systems with sub-microsecond resolution timers, or where (HZ/100000) 1343is not an integer, the 1344.Em NTP 1345option also enables extended-precision arithmetic to keep track of 1346fractional clock ticks at NTP time-format precision. 1347.It Cd options PPS_SYNC 1348This option enables a kernel serial line discipline for receiving time 1349phase signals from an external reference clock such as a radio clock. 1350.Po 1351The 1352.Em NTP 1353option (which see) must be on if the 1354.Em PPS_SYNC 1355option is used 1356.Pc . 1357Some reference clocks generate a Pulse Per Second (PPS) signal in 1358phase with their time source. 1359The 1360.Em PPS 1361line discipline receives this signal on either the data leads 1362or the DCD control lead of a serial port. 1363.Pp 1364.Em NTP 1365uses the PPS signal to discipline the local clock oscillator to a high 1366degree of precision (typically less than 50 microseconds in time and 13670.1 ppm in accuracy). 1368.Em PPS 1369can also generate a serial output pulse when the system receives a PPS 1370interrupt. 1371This can be used to measure the system interrupt latency and thus calibrate 1372.Em NTP 1373to account for it. 1374Using 1375.Em PPS 1376usually requires a gadget box 1377to convert from 1378.Tn TTL 1379to 1380.Tn RS-232 1381signal levels. 1382The gadget box and PPS are described in more detail in the HTML documentation 1383for 1384.Xr ntpd 8 1385in 1386.Pa /usr/share/doc/html/ntp . 1387.Pp 1388.Nx 1389currently supports this option in 1390.Xr com 4 1391and 1392.Xr zsc 4 . 1393.It Cd options SETUIDSCRIPTS 1394Allows scripts with the setuid bit set to execute as the effective 1395user rather than the real user, just like binary executables. 1396.Pp 1397.Em NOTE : 1398Using this option will also enable 1399.Em options FDSCRIPTS 1400.It Cd options FDSCRIPTS 1401Allows execution of scripts with the execute bit set, but not the 1402read bit, by opening the file and passing the file descriptor to 1403the shell, rather than the filename. 1404.Pp 1405.Em NOTE : 1406Execute only (non-readable) scripts will have 1407.Va argv[0] 1408set to 1409.Pa /dev/fd/* . 1410What this option allows as far as security is 1411concerned, is the ability to safely ensure that the correct script 1412is run by the interpreter, as it is passed as an already open file. 1413.It Cd options RTC_OFFSET=integer 1414The kernel (and typically the hardware battery backed-up clock on 1415those machines that have one) keeps time in 1416.Em UTC 1417(Universal Coordinated Time, once known as 1418.Em GMT , 1419or Greenwich Mean Time) 1420and not in the time of the local time zone. 1421The 1422.Em RTC_OFFSET 1423option is used on some ports (such as the i386) to tell the kernel 1424that the hardware clock is offset from 1425.Em UTC 1426by the specified number of minutes. 1427This is typically used when a machine boots several operating 1428systems and one of them wants the hardware clock to run in the 1429local time zone and not in 1430.Em UTC , 1431e.g. 1432.Em RTC_OFFSET=300 1433means 1434the hardware clock is set to US Eastern Time (300 minutes behind 1435.Em UTC ) , 1436and not 1437.Em UTC . 1438(Note: 1439.Em RTC_OFFSET 1440is used to initialize a kernel variable named 1441.Va rtc_offset 1442which is the source actually used to determine the clock offset, and 1443which may be accessed via the kern.rtc_offset sysctl variable. 1444See 1445.Xr sysctl 8 1446and 1447.Xr sysctl 3 1448for details. 1449Since the kernel clock is initialized from the hardware clock very 1450early in the boot process, it is not possible to meaningfully change 1451.Va rtc_offset 1452in system initialization scripts. 1453Changing this value currently may only be done at kernel compile 1454time or by patching the kernel and rebooting). 1455.Pp 1456.Em NOTE : 1457Unfortunately, in many cases where the hardware clock 1458is kept in local time, it is adjusted for Daylight Savings 1459Time; this means that attempting to use 1460.Em RTC_OFFSET 1461to let 1462.Nx 1463coexist with such an operating system, like Windows, 1464would necessitate changing 1465.Em RTC_OFFSET 1466twice a year. 1467As such, this solution is imperfect. 1468.It Cd options MAXUPRC=integer 1469Sets the soft 1470.Dv RLIMIT_NPROC 1471resource limit, which specifies the maximum number of simultaneous 1472processes a user is permitted to run, for process 0; 1473this value is inherited by its child processes. 1474It defaults to 1475.Em CHILD_MAX , 1476which is currently defined to be 160. 1477Setting 1478.Em MAXUPRC 1479to a value less than 1480.Em CHILD_MAX 1481is not permitted, as this would result in a violation of the semantics of 1482.St -p1003.1-90 . 1483.It Cd options NOFILE=integer 1484Sets the soft 1485.Dv RLIMIT_NOFILE 1486resource limit, which specifies the maximum number of open 1487file descriptors for each process; 1488this value is inherited by its child processes. 1489It defaults to 1490.Em OPEN_MAX , 1491which is currently defined to be 128. 1492.It Cd options MAXFILES=integer 1493Sets the default value of the 1494.Em kern.maxfiles 1495sysctl variable, which indicates the maximum number of files that may 1496be open in the system. 1497.It Cd options DEFCORENAME=string 1498Sets the default value of the 1499.Em kern.defcorename 1500sysctl variable, otherwise it is set to 1501.Nm %n.core . 1502See 1503.Xr sysctl 8 1504and 1505.Xr sysctl 3 1506for details. 1507.It Cd options RASOPS_CLIPPING 1508Enables clipping within the 1509.Nm rasops 1510raster-console output system. 1511.Em NOTE : 1512only available on architectures that use 1513.Nm rasops 1514for console output. 1515.It Cd options RASOPS_SMALL 1516Removes optimized character writing code from the 1517.Nm rasops 1518raster-console output system. 1519.Em NOTE : 1520only available on architectures that use 1521.Nm rasops 1522for console output. 1523.It Cd options INCLUDE_CONFIG_FILE 1524Embeds the kernel config file used to define the kernel in the kernel 1525binary itself. 1526The embedded data also includes any files directly included by the config 1527file itself, e.g. 1528.Pa GENERIC.local 1529or 1530.Pa std.$MACHINE . 1531The embedded config file can be extracted from the resulting kernel with 1532.Xr config 1 1533.Fl x , 1534or by the following command: 1535.Bd -literal -offset indent 1536strings netbsd | sed -n 's/^_CFG_//p' | unvis 1537.Ed 1538.It Cd options INCLUDE_JUST_CONFIG 1539Similar to the above option, but includes just the actual config file, 1540not any included files. 1541.It Cd options PIPE_SOCKETPAIR 1542Use slower, but smaller socketpair(2)-based pipe implementation instead 1543of default faster, but bigger one. 1544Primarily useful for installation kernels. 1545.It Cd options USERCONF 1546Compiles in the in-kernel device configuration manager. 1547See 1548.Xr userconf 4 1549for details. 1550.It Cd options PERFCTRS 1551Compiles in kernel support for CPU performance-monitoring counters. 1552See 1553.Xr pmc 1 1554for details. 1555.Em NOTE : 1556not available on all architectures. 1557.It Cd options SCDEBUG_DEFAULT 1558Used with the 1559.Cd options SYSCALL_DEBUG 1560described below to choose which types of events are displayed. 1561.Pp 1562.Bl -tag -width "SCDEBUG_KERNHIST" -compact -offset indent 1563.It Dv SCDEBUG_CALLS 1564Show system call entry points. 1565.It Dv SCDEBUG_RETURNS 1566Show system call exit points. 1567.It Dv SCDEBUG_ALL 1568Show all system call requestes, including unimplemented calls. 1569.It Dv SCDEBUG_SHOWARGS 1570Show the arguments provided. 1571.It Dv SCDEBUG_KERNHIST 1572Store a restricted form of the system call debug in a kernel history 1573instead of printing it to the console. 1574This option relies upon 1575.Cd options KERNHIST . 1576.El 1577.Pp 1578The default value is 1579.Dv (SCDEBUG_CALLS|SCDEBUG_RETURNS|SCDEBUG_SHOWARGS) . 1580.It Cd options SYSCALL_DEBUG 1581Useful for debugging system call issues, usually in early single user bringup. 1582By default, writes entries to the system console for most system call events. 1583Can be configured with the 1584.Cd options SCDEBUG_DEFAULT 1585option to to use the 1586.Cd options KERNHIST 1587facility instead. 1588.It Cd options SYSCALL_STATS 1589Count the number of times each system call number is called. 1590The values can be read through the sysctl interface and displayed using 1591.Xr systat 1 . 1592.Em NOTE : 1593not yet available on all architectures. 1594.It Cd options SYSCALL_TIMES 1595Count the time spent (using 1596.Fn cpu_counter32 ) 1597in each system call. 1598.Em NOTE : 1599Using this option will also enable 1600.Cd options SYSCALL_STATS . 1601.It Cd options SYSCALL_TIMES_HASCOUNTER 1602Force use of 1603.Fn cpu_counter32 1604even if 1605.Fn cpu_hascounter 1606reports false. 1607Useful for systems where the cycle counter doesn't run at a constant rate 1608(e.g. Soekris boxes). 1609.It Cd options XSERVER_DDB 1610A supplement to XSERVER that adds support for entering 1611.Xr ddb 4 1612while in 1613.Tn X11 . 1614.It Cd options FILEASSOC 1615Support for 1616.Xr fileassoc 9 . 1617Required for 1618.Cd options PAX_SEGVGUARD 1619and 1620.Cd pseudo-device veriexec . 1621.It Cd options FILEASSOC_NHOOKS=integer 1622Number of storage slots per file for 1623.Xr fileassoc 9 . 1624Default is 4. 1625.El 1626.Ss Networking Options 1627.Bl -ohang 1628.It Cd options GATEWAY 1629Enables 1630.Em IPFORWARDING 1631(which see) 1632and (on most ports) increases the size of 1633.Em NMBCLUSTERS 1634(which see). 1635In general, 1636.Em GATEWAY 1637is used to indicate that a system should act as a router, and 1638.Em IPFORWARDING 1639is not invoked directly. 1640(Note that 1641.Em GATEWAY 1642has no impact on protocols other than 1643.Tn IP , 1644such as 1645.Tn CLNP ) . 1646.Em GATEWAY 1647option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1648.It Cd options ICMPPRINTFS 1649The 1650.Em ICMPPRINTFS 1651option will enable debugging information to be printed about 1652the 1653.Xr icmp 4 1654protocol. 1655.It Cd options IPFORWARDING=value 1656If 1657.Em value 1658is 1 this enables IP routing behavior. 1659If 1660.Em value 1661is 0 (the default), it disables it. 1662The 1663.Em GATEWAY 1664option sets this to 1 automatically. 1665With this option enabled, the machine will forward IP datagrams destined 1666for other machines between its interfaces. 1667Note that even without this option, the kernel will 1668still forward some packets (such as source routed packets) -- removing 1669.Em GATEWAY 1670and 1671.Em IPFORWARDING 1672is insufficient to stop all routing through a bastion host on a 1673firewall -- source routing is controlled independently. 1674To turn off source routing, use 1675.Em options IPFORWSRCRT=0 1676(which see). 1677Note that IP forwarding may be turned on and off independently of the 1678setting of the 1679.Em IPFORWARDING 1680option through the use of the 1681.Em net.inet.ip.forwarding 1682sysctl variable. 1683If 1684.Em net.inet.ip.forwarding 1685is 1, IP forwarding is on. 1686See 1687.Xr sysctl 8 1688and 1689.Xr sysctl 3 1690for details. 1691.It Cd options IPFORWSRCRT=value 1692If 1693.Em value 1694is set to zero, source routing of IP datagrams is turned off. 1695If 1696.Em value 1697is set to one (the default) or the option is absent, source routed IP 1698datagrams are forwarded by the machine. 1699Note that source routing of IP packets may be turned on and off 1700independently of the setting of the 1701.Em IPFORWSRCRT 1702option through the use of the 1703.Em net.inet.ip.forwsrcrt 1704sysctl variable. 1705If 1706.Em net.inet.ip.forwsrcrt 1707is 1, forwarding of source routed IP datagrams is on. 1708See 1709.Xr sysctl 8 1710and 1711.Xr sysctl 3 1712for details. 1713.It Cd options IFA_STATS 1714Tells the kernel to maintain per-address statistics on bytes sent 1715and received over (currently) Internet and AppleTalk addresses. 1716.\"This can be a fairly expensive operation, so you probably want to 1717.\"keep this disabled. 1718The option is not recommended as it degrades system stability. 1719.It Cd options IFQ_MAXLEN=value 1720Increases the allowed size of the network interface packet queues. 1721The default queue size is 50 packets, and you do not normally need 1722to increase it. 1723.It Cd options IPSELSRC 1724Includes support for source-address selection policies. 1725See 1726.Xr in_getifa 9 . 1727.It Cd options MROUTING 1728Includes support for IP multicast routers. 1729You certainly want 1730.Em INET 1731with this. 1732Multicast routing is controlled by the 1733.Xr mrouted 8 1734daemon. 1735See also option 1736.Cd PIM . 1737.It Cd options PIM 1738Includes support for Protocol Independent Multicast (PIM) routing. 1739You need 1740.Em MROUTING 1741and 1742.Em INET 1743with this. 1744Software using this can be found e.g. in 1745.Pa pkgsrc/net/xorp . 1746.It Cd options INET 1747Includes support for the 1748.Tn TCP/IP 1749protocol stack. 1750You almost certainly want this. 1751See 1752.Xr inet 4 1753for details. 1754.It Cd options INET6 1755Includes support for the 1756.Tn IPv6 1757protocol stack. 1758See 1759.Xr inet6 4 1760for details. 1761Unlike 1762.Em INET , 1763.Em INET6 1764enables multicast routing code as well. 1765This option requires 1766.Em INET 1767at this moment, but it should not. 1768.It Cd options ND6_DEBUG 1769The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1770for debugging IPv6 neighbor discovery protocol handling. 1771See 1772.Xr sysctl 3 1773for details. 1774.It Cd options IPSEC 1775Includes support for the 1776.Tn IPsec 1777protocol, using the implementation derived from 1778.Ox , 1779relying on 1780.Xr opencrypto 9 1781to carry out cryptographic operations. 1782See 1783.Xr fast_ipsec 4 1784for details. 1785.It Cd options IPSEC_DEBUG 1786Enables debugging code in 1787.Tn IPsec 1788stack. 1789See 1790.Xr ipsec 4 1791for details. 1792The 1793.Cd IPSEC 1794option includes support for 1795.Tn IPsec 1796Network Address Translator traversal (NAT-T), as described in RFCs 3947 1797and 3948. 1798This feature might be patent-encumbered in some countries. 1799.It Cd options ALTQ 1800Enabled ALTQ (Alternate Queueing). 1801For simple rate-limiting, use 1802.Xr tbrconfig 8 1803to set up the interface transmission rate. 1804To use queueing disciplines, their appropriate kernel options should also 1805be defined (documented below). 1806Queueing disciplines are managed by 1807.Xr altqd 8 . 1808See 1809.Xr altq 9 1810for details. 1811.It Cd options ALTQ_HFSC 1812Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1813module. 1814HFSC supports both link-sharing and guaranteed real-time services. 1815HFSC employs a service curve based QoS model, and its unique feature 1816is an ability to decouple delay and bandwidth allocation. 1817Requires 1818.Em ALTQ_RED 1819to use the RED queueing discipline on HFSC classes, or 1820.Em ALTQ_RIO 1821to use the RIO queueing discipline on HFSC classes. 1822This option assumes 1823.Em ALTQ . 1824.It Cd options ALTQ_PRIQ 1825Include support for ALTQ-implemented PRIQ (Priority Queueing). 1826PRIQ implements a simple priority-based queueing discipline. 1827A higher priority class is always served first. 1828Requires 1829.Em ALTQ_RED 1830to use the RED queueing discipline on HFSC classes, or 1831.Em ALTQ_RIO 1832to use the RIO queueing discipline on HFSC classes. 1833This option assumes 1834.Em ALTQ . 1835.It Cd options ALTQ_WFQ 1836Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1837WFQ implements a weighted-round robin scheduler for a set of queues. 1838A weight can be assigned to each queue to give a different proportion 1839of the link capacity. 1840A hash function is used to map a flow to one of a set of queues. 1841This option assumes 1842.Em ALTQ . 1843.It Cd options ALTQ_FIFOQ 1844Include support for ALTQ-implemented FIFO queueing. 1845FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1846This option assumes 1847.Em ALTQ . 1848.It Cd options ALTQ_RIO 1849Include support for ALTQ-implemented RIO (RED with In/Out). 1850The original RIO has 2 sets of RED parameters; one for in-profile 1851packets and the other for out-of-profile packets. 1852At the ingress of the network, profile meters tag packets as IN or 1853OUT based on contracted profiles for customers. 1854Inside the network, IN packets receive preferential treatment by 1855the RIO dropper. 1856ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1857PHB of DiffServ (RFC 2597). 1858This option assumes 1859.Em ALTQ . 1860.It Cd options ALTQ_BLUE 1861Include support for ALTQ-implemented Blue buffer management. 1862Blue is another active buffer management mechanism. 1863This option assumes 1864.Em ALTQ . 1865.It Cd options ALTQ_FLOWVALVE 1866Include support for ALTQ-implemented Flowvalve. 1867Flowvalve is a simple implementation of a RED penalty box that identifies 1868and punishes misbehaving flows. 1869This option requires 1870.Em ALTQ_RED 1871and assumes 1872.Em ALTQ . 1873.It Cd options ALTQ_CDNR 1874Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1875packet marking/manipulation. 1876Traffic conditioners are components to meter, mark, or drop incoming 1877packets according to some rules. 1878As opposed to queueing disciplines, traffic conditioners handle incoming 1879packets at an input interface. 1880This option assumes 1881.Em ALTQ . 1882.It Cd options ALTQ_NOPCC 1883Disables use of processor cycle counter to measure time in ALTQ. 1884This option should be defined for a non-Pentium i386 CPU which does not 1885have TSC, SMP (per-CPU counters are not in sync), or power management 1886which affects processor cycle counter. 1887This option assumes 1888.Em ALTQ . 1889.It Cd options ALTQ_IPSEC 1890Include support for IPsec in IPv4 ALTQ. 1891This option assumes 1892.Em ALTQ . 1893.It Cd options ALTQ_JOBS 1894Include support for ALTQ-implemented JoBS (Joint Buffer Management 1895and Scheduling). 1896This option assumes 1897.Em ALTQ . 1898.It Cd options ALTQ_AFMAP 1899Include support for an undocumented ALTQ feature that is used to map an IP 1900flow to an ATM VC (Virtual Circuit). 1901This option assumes 1902.Em ALTQ . 1903.It Cd options ALTQ_LOCALQ 1904Include support for ALTQ-implemented local queues. 1905Its practical use is undefined. 1906Assumes 1907.Em ALTQ . 1908.It Cd options SUBNETSARELOCAL 1909Sets default value for net.inet.ip.subnetsarelocal variable, which 1910controls whether non-directly-connected subnets of connected networks 1911are considered "local" for purposes of choosing the MSS for a TCP 1912connection. 1913This is mostly present for historic reasons and completely irrelevant if 1914you enable Path MTU discovery. 1915.It Cd options HOSTZEROBROADCAST 1916Sets default value for net.inet.ip.hostzerobroadcast variable, which 1917controls whether the zeroth host address of each connected subnet is 1918also considered a broadcast address. 1919Default value is "1", for compatibility with old systems; if this is 1920set to zero on all hosts on a subnet, you should be able to fit an extra 1921host per subnet on the 1922".0" address. 1923.It Cd options MCLSHIFT=value 1924This option is the base-2 logarithm of the size of mbuf clusters. 1925The 1926.Bx 1927networking stack keeps network packets in a linked 1928list, or chain, of kernel buffer objects called mbufs. 1929The system provides larger mbuf clusters as an optimization for 1930large packets, instead of using long chains for large packets. 1931The mbuf cluster size, 1932or 1933.Em MCLBYTES , 1934must be a power of two, and is computed as two raised to the power 1935.Em MCLSHIFT . 1936On systems with Ethernet network adapters, 1937.Em MCLSHIFT 1938is often set to 11, giving 2048-byte mbuf clusters, large enough to 1939hold a 1500-byte 1940.Tn Ethernet 1941frame in a single cluster. 1942Systems with network interfaces supporting larger frame sizes like 1943.Tn ATM , 1944.Tn FDDI , 1945or 1946.Tn HIPPI 1947may perform better with 1948.Em MCLSHIFT 1949set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1950respectively. 1951.It Cd options NETATALK 1952Include support for the 1953.Tn AppleTalk 1954protocol stack. 1955The kernel provides provision for the 1956.Em Datagram Delivery Protocol 1957(DDP), providing SOCK_DGRAM support and 1958.Tn AppleTalk 1959routing. 1960This stack is used by the 1961.Em NETATALK 1962package, which adds support for 1963.Tn AppleTalk 1964server services via user libraries and applications. 1965.It Cd options BLUETOOTH 1966Include support for the 1967.Tn Bluetooth 1968protocol stack. 1969See 1970.Xr bluetooth 4 1971for details. 1972.It Cd options IPNOPRIVPORTS 1973Normally, only root can bind a socket descriptor to a so-called 1974.Dq privileged 1975.Tn TCP 1976port, that is, a port number in the range 0-1023. 1977This option eliminates those checks from the kernel. 1978This can be useful if there is a desire to allow daemons without 1979privileges to bind those ports, e.g., on firewalls. 1980The security tradeoffs in doing this are subtle. 1981This option should only be used by experts. 1982.It Cd options TCP_COMPAT_42 1983.Tn TCP 1984bug compatibility with 1985.Bx 4.2 . 1986In 1987.Bx 4.2 , 1988.Tn TCP 1989sequence numbers were 32-bit signed values. 1990Modern implementations of TCP use unsigned values. 1991This option clamps the initial sequence number to start in 1992the range 2^31 rather than the full unsigned range of 2^32. 1993Also, under 1994.Bx 4.2 , 1995keepalive packets must contain at least one byte or else 1996the remote end would not respond. 1997.It Cd options TCP_DEBUG 1998Record the last 1999.Em TCP_NDEBUG 2000TCP packets with SO_DEBUG set, and decode to the console if 2001.Em tcpconsdebug 2002is set. 2003.It Cd options TCP_NDEBUG 2004Number of packets to record for 2005.Em TCP_DEBUG . 2006Defaults to 100. 2007.It Cd options TCP_SENDSPACE=value 2008.It Cd options TCP_RECVSPACE=value 2009These options set the max TCP window size to other sizes than the default. 2010The TCP window sizes can be altered via 2011.Xr sysctl 8 2012as well. 2013.It Cd options TCP_INIT_WIN=value 2014This option sets the initial TCP window size for non-local connections, 2015which is used when the transmission starts. 2016The default size is 1, but if the machine should act more aggressively, 2017the initial size can be set to some other value. 2018The initial TCP window size can be set via 2019.Xr sysctl 8 2020as well. 2021.It Cd options TCP_SIGNATURE 2022Enable MD5 TCP signatures (RFC 2385) to protect BGP sessions. 2023.It Cd options IPFILTER_LOG 2024This option, in conjunction with 2025.Em pseudo-device ipfilter , 2026enables logging of IP packets using IP-Filter. 2027.It Cd options IPFILTER_LOOKUP 2028This option enables the 2029IP-Filter 2030.Xr ippool 8 2031functionality to be enabled. 2032.It Cd options IPFILTER_COMPAT 2033This option enables older IP-Filter binaries to work. 2034.It Cd options IPFILTER_DEFAULT_BLOCK 2035This option sets the default policy of IP-Filter. 2036If it is set, IP-Filter will block packets by default. 2037.It Cd options BRIDGE_IPF 2038This option causes 2039.Em bridge 2040devices to use the IP and/or IPv6 filtering hooks, forming 2041a link-layer filter that uses protocol-layer rules. 2042This option assumes the presence of 2043.Em pseudo-device ipfilter . 2044.It Cd options MBUFTRACE 2045This option can help track down mbuf leaks. 2046When enabled, mbufs are tagged with the devices and protocols using them, 2047which slightly decreases network performance. 2048This additional information can be viewed with 2049.Xr netstat 1 : 2050.Dl Ic netstat Fl mssv 2051Not all devices or protocols support this option. 2052.El 2053.Ss Sysctl Related Options 2054.Bl -ohang 2055.It Cd options SYSCTL_DISALLOW_CREATE 2056Disallows the creation or deletion of nodes from the sysctl tree, as 2057well as the assigning of descriptions to nodes that lack them, by any 2058process. 2059These operations are still available to kernel sub-systems, including 2060loadable kernel modules. 2061.It Cd options SYSCTL_DISALLOW_KWRITE 2062Prevents processes from adding nodes to the sysctl tree that make 2063existing kernel memory areas writable. 2064Sections of kernel memory can still be read and new nodes that own 2065their own data may still be writable. 2066.It Cd options SYSCTL_DEBUG_SETUP 2067Causes the SYSCTL_SETUP routines to print a brief message when they 2068are invoked. 2069This is merely meant as an aid in determining the order in which 2070sections of the tree are created. 2071.It Cd options SYSCTL_DEBUG_CREATE 2072Prints a message each time 2073.Fn sysctl_create , 2074the function that adds nodes to the tree, is called. 2075.It Cd options SYSCTL_INCLUDE_DESCR 2076Causes the kernel to include short, human readable descriptions for 2077nodes in the sysctl tree. 2078The descriptions can be retrieved programmatically (see 2079.Xr sysctl 3 ) , 2080or by the sysctl binary itself (see 2081.Xr sysctl 8 ) . 2082The descriptions are meant to give an indication of the purpose and/or 2083effects of a given node's value, not replace the documentation for the 2084given subsystem as a whole. 2085.El 2086.Ss System V IPC Options 2087.Bl -ohang 2088.It Cd options SYSVMSG 2089Includes support for 2090.At V 2091style message queues. 2092See 2093.Xr msgctl 2 , 2094.Xr msgget 2 , 2095.Xr msgrcv 2 , 2096.Xr msgsnd 2 . 2097.It Cd options SYSVSEM 2098Includes support for 2099.At V 2100style semaphores. 2101See 2102.Xr semctl 2 , 2103.Xr semget 2 , 2104.Xr semop 2 . 2105.It Cd options SEMMNI=value 2106Sets the number of 2107.At V 2108style semaphore identifiers. 2109The GENERIC config file for your port will have the default. 2110.It Cd options SEMMNS=value 2111Sets the number of 2112.At V 2113style semaphores in the system. 2114The GENERIC config file for your port will have the default. 2115.It Cd options SEMUME=value 2116Sets the maximum number of undo entries per process for 2117.At V 2118style semaphores. 2119The GENERIC config file for your port will have the default. 2120.It Cd options SEMMNU=value 2121Sets the number of undo structures in the system for 2122.At V 2123style semaphores. 2124The GENERIC config file for your port will have the default. 2125.It Cd options SYSVSHM 2126Includes support for 2127.At V 2128style shared memory. 2129See 2130.Xr shmat 2 , 2131.Xr shmctl 2 , 2132.Xr shmdt 2 , 2133.Xr shmget 2 . 2134.It Cd options SHMMAXPGS=value 2135Sets the maximum number of 2136.At V 2137style shared memory pages that are available through the 2138.Xr shmget 2 2139system call. 2140Default value is 1024 on most ports. 2141See 2142.Pa /usr/include/machine/vmparam.h 2143for the default. 2144.El 2145.Ss VM Related Options 2146.Bl -ohang 2147.It Cd options NMBCLUSTERS=value 2148The number of mbuf clusters the kernel supports. 2149Mbuf clusters are MCLBYTES in size (usually 2k). 2150This is used to compute the size of the kernel VM map 2151.Em mb_map , 2152which maps mbuf clusters. 2153Default on most ports is 1024 (2048 with 2154.Dq options GATEWAY 2155). 2156See 2157.Pa /usr/include/machine/param.h 2158for exact default information. 2159Increase this value if you get 2160.Dq mclpool limit reached 2161messages. 2162.It Cd options NKMEMPAGES=value 2163.It Cd options NKMEMPAGES_MIN=value 2164.It Cd options NKMEMPAGES_MAX=value 2165Size of kernel VM map 2166.Em kmem_map , 2167in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2168from the 2169.Xr sysctl 8 2170variable 2171.Em hw.pagesize 2172). 2173This VM map is used to map the kernel malloc arena. 2174The kernel attempts to auto-size this map based on the amount of 2175physical memory in the system. 2176Platform-specific code may place bounds on this computed size, 2177which may be viewed with the 2178.Xr sysctl 8 2179variable 2180.Em vm.nkmempages . 2181See 2182.Pa /usr/include/machine/param.h 2183for the default upper and lower bounds. 2184The related options 2185.Sq NKMEMPAGES_MIN 2186and 2187.Sq NKMEMPAGES_MAX 2188allow the bounds to be overridden in the kernel configuration file. 2189These options are provided in the event the computed value is 2190insufficient resulting in an 2191.Dq out of space in kmem_map 2192panic. 2193.It Cd options SB_MAX=value 2194Sets the max size in bytes that a socket buffer is allowed to occupy. 2195The default is 256k, but sometimes it needs to be increased, for example 2196when using large TCP windows. 2197This option can be changed via 2198.Xr sysctl 8 2199as well. 2200.It Cd options SOMAXKVA=value 2201Sets the maximum size of kernel virtual memory that the socket buffers 2202are allowed to use. 2203The default is 16MB, but in situations where for example large TCP 2204windows are used this value must also be increased. 2205This option can be changed via 2206.Xr sysctl 8 2207as well. 2208.It Cd options BUFCACHE=value 2209Size of the buffer cache as a percentage of total available 2210.Tn RAM . 2211Ignored if BUFPAGES is also specified. 2212.It Cd options NBUF=value 2213Sets the number of buffer headers available, i.e., the number of 2214open files that may have a buffer cache entry. 2215Each buffer header 2216requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2217The default value is machine dependent, but is usually equal to the 2218value of BUFPAGES. 2219.It Cd options BUFPAGES=value 2220These options set the number of pages available for the buffer cache. 2221Their default value is a machine dependent value, often calculated as 2222between 5% and 10% of total available 2223.Tn RAM . 2224.It Cd options MAXTSIZ=bytes 2225Sets the maximum size limit of a process' text segment. 2226See 2227.Pa /usr/include/machine/vmparam.h 2228for the port-specific default. 2229.It Cd options DFLDSIZ=bytes 2230Sets the default size limit of a process' data segment, the value that 2231will be returned as the soft limit for 2232.Dv RLIMIT_DATA 2233(as returned by 2234.Xr getrlimit 2 ) . 2235See 2236.Pa /usr/include/machine/vmparam.h 2237for the port-specific default. 2238.It Cd options MAXDSIZ=bytes 2239Sets the maximum size limit of a process' data segment, the value that 2240will be returned as the hard limit for 2241.Dv RLIMIT_DATA 2242(as returned by 2243.Xr getrlimit 2 ) . 2244See 2245.Pa /usr/include/machine/vmparam.h 2246for the port-specific default. 2247.It Cd options DFLSSIZ=bytes 2248Sets the default size limit of a process' stack segment, the value that 2249will be returned as the soft limit for 2250.Dv RLIMIT_STACK 2251(as returned by 2252.Xr getrlimit 2 ) . 2253See 2254.Pa /usr/include/machine/vmparam.h 2255for the port-specific default. 2256.It Cd options MAXSSIZ=bytes 2257Sets the maximum size limit of a process' stack segment, the value that 2258will be returned as the hard limit for 2259.Dv RLIMIT_STACK 2260(as returned by 2261.Xr getrlimit 2 ) . 2262See 2263.Pa /usr/include/machine/vmparam.h 2264for the port-specific default. 2265.It Cd options DUMP_ON_PANIC=integer 2266Defaults to one. 2267If set to zero, the kernel will not dump to the dump device when 2268it panics, though dumps can still be forced via 2269.Xr ddb 4 2270with the 2271.Dq sync 2272command. 2273Note that this sets the value of the 2274.Em kern.dump_on_panic 2275.Xr sysctl 3 2276variable which may be changed at run time -- see 2277.Xr sysctl 8 2278for details. 2279.It Cd options USE_TOPDOWN_VM 2280User space memory allocations (as made by 2281.Xr mmap 2 ) 2282will be arranged in a 2283.Dq top down 2284fashion instead of the traditional 2285.Dq upwards from MAXDSIZ \&+ vm_daddr 2286method. 2287This includes the placement of 2288.Xr ld.so 1 . 2289Arranging memory in this manner allows either (or both of) the heap or 2290.Xr mmap 2 2291allocated space to grow larger than traditionally possible. 2292This option is not available on all ports, but is instead expected to be 2293offered on a port-by-port basis, after which some ports will commit to 2294using it by default. 2295See the files 2296.Pa /usr/include/uvm/uvm_param.h 2297for some implementation details, and 2298.Pa /usr/include/machine/vmparam.h 2299for port specific details including availability. 2300.It Cd options VMSWAP 2301Enable paging device/file support. 2302This option is on by default. 2303.It Cd options PDPOLICY_CLOCKPRO 2304Use CLOCK-Pro, an alternative page replace policy. 2305.El 2306.Ss Security Options 2307.Bl -ohang 2308.It Cd options INSECURE 2309Initializes the kernel security level with \-1 instead of 0. 2310This means that the system always starts in secure level \-1 mode, even when 2311running multiuser, unless the securelevel variable is set to value > \-1 in 2312.Pa /etc/rc.conf . 2313In this case the kernel security level will be raised to that value when the 2314.Pa /etc/rc.d/securelevel 2315script is run during system startup. 2316See the manual page for 2317.Xr init 8 2318for details on the implications of this. 2319The kernel secure level may manipulated by the superuser by altering the 2320.Em kern.securelevel 2321.Xr sysctl 3 2322variable (the secure level may only be lowered by a call from process ID 1, 2323i.e., 2324.Xr init 8 ) . 2325See also 2326.Xr secmodel_securelevel 9 , 2327.Xr sysctl 8 2328and 2329.Xr sysctl 3 . 2330.It Cd options VERIFIED_EXEC_FP_MD5 2331Enables support for MD5 hashes in Veriexec. 2332.It Cd options VERIFIED_EXEC_FP_SHA1 2333Enables support for SHA1 hashes in Veriexec. 2334.It Cd options VERIFIED_EXEC_FP_RMD160 2335Enables support for RMD160 hashes in Veriexec. 2336.It Cd options VERIFIED_EXEC_FP_SHA256 2337Enables support for SHA256 hashes in Veriexec. 2338.It Cd options VERIFIED_EXEC_FP_SHA384 2339Enables support for SHA384 hashes in Veriexec. 2340.It Cd options VERIFIED_EXEC_FP_SHA512 2341Enables support for SHA512 hashes in Veriexec. 2342.It Cd options PAX_MPROTECT=value 2343Enables PaX MPROTECT, 2344.Xr mprotect 2 2345restrictions from the PaX project. 2346.Pp 2347The 2348.Ar value 2349is the default value for the 2350.Em global 2351knob, see 2352.Xr sysctl 3 . 2353If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2354using 2355.Xr paxctl 8 . 2356If 1, PaX MPROTECT will be enabled for all programs. 2357Programs can be exempted using 2358.Xr paxctl 8 . 2359.Pp 2360See 2361.Xr security 7 2362for more details. 2363.It Cd options PAX_SEGVGUARD=value 2364Enables PaX Segvguard. 2365Requires 2366.Cd options FILEASSOC . 2367.Pp 2368The 2369.Ar value 2370is the default value for the 2371.Em global 2372knob, see 2373.Xr sysctl 3 . 2374If 0, PaX Segvguard will be enabled only if explicitly set on programs 2375using 2376.Xr paxctl 8 . 2377If 1, PaX Segvguard will be enabled to all programs, and exemption can 2378be done using 2379.Xr paxctl 8 . 2380.Pp 2381See 2382.Xr security 7 2383for more details. 2384.It Cd options PAX_ASLR=value 2385Enables PaX ASLR. 2386.Pp 2387The 2388.Ar value 2389is the default value for the 2390.Em global 2391knob, see 2392.Xr sysctl 3 . 2393If 0, PaX ASLR will be enabled only if explicitly set on programs 2394using 2395.Xr paxctl 8 . 2396If 1, PaX ASLR will be enabled to all programs, and exemption can 2397be done using 2398.Xr paxctl 8 . 2399.Pp 2400See 2401.Xr security 7 2402for more details. 2403.It Cd options USER_VA0_DISABLE_DEFAULT=value 2404Sets the initial value of the flag which controls whether user programs 2405can map virtual address 0. 2406The flag can be changed at runtime by 2407.Xr sysctl 3 . 2408.El 2409.Ss amiga-specific Options 2410.Bl -ohang 2411.It Cd options BB060STUPIDROM 2412When the bootloader (which passes 2413.Tn AmigaOS 2414.Tn ROM 2415information) claims we have a 68060 2416.Tn CPU 2417without 2418.Tn FPU , 2419go look into the Processor Configuration Register (PCR) to find out. 2420You need this with 2421.Tn Amiga 2422.Tn ROM Ns s 2423up to (at least) V40.xxx (OS3.1), 2424when you boot via the bootblocks and don't have a DraCo. 2425.It Cd options IOBZCLOCK=frequency 2426The IOBlix boards come with two different serial master clocks: older ones 2427use 24 MHz, newer ones use 22.1184 MHz. 2428The driver normally assumes the latter. 2429If your board uses 24 MHz, you can recompile your kernel with 2430options IOBZCLOCK=24000000 2431or patch the kernel variable 2432.Tn iobzclock 2433to the same value. 2434.It Cd options LIMITMEM=value 2435If there, limit the part of the first memory bank used by 2436.Nx 2437to value megabytes. 2438Default is unlimited. 2439.It Cd options P5PPC68KBOARD 2440Add special support for Phase5 mixed 68k+PPC boards. 2441Currently, this only affects rebooting from 2442.Nx 2443and is only needed on 68040+PPC, not on 244468060+PPC; without this, affected machines will hang after 2445.Nx 2446has shut 2447down and will only restart after a keyboard reset or a power cycle. 2448.El 2449.Ss atari-specific Options 2450.Bl -ohang 2451.It Cd options DISKLABEL_AHDI 2452Include support for AHDI (native Atari) disklabels. 2453.It Cd options DISKLABEL_NBDA 2454Include support for 2455.Nx Ns Tn /atari 2456labels. 2457If you don't set this option, it will be set automatically. 2458.Nx Ns Tn /atari 2459will not work without it. 2460.It Cd options FALCON_SCSI 2461Include support for the 5380-SCSI configuration as found on the Falcon. 2462.It Cd options RELOC_KERNEL 2463If set, the kernel will relocate itself to TT-RAM, if possible. 2464This will give you a slightly faster system. 2465.Em Beware 2466that on some TT030 systems, 2467the system will frequently dump with MMU-faults with this option enabled. 2468.It Cd options SERCONSOLE 2469Allow the modem1-port to act as the system-console. 2470A carrier should be active on modem1 during system boot to active 2471the console functionality. 2472.It Cd options TT_SCSI 2473Include support for the 5380-SCSI configuration as found on the TT030 2474and Hades. 2475.El 2476.Ss i386-specific Options 2477.Bl -ohang 2478.It Cd options CPURESET_DELAY=value 2479Specifies the time (in millisecond) to wait before doing a hardware reset 2480in the last phase of a reboot. 2481This gives the user a chance to see error messages from the shutdown 2482operations (like NFS unmounts, buffer cache flush, etc ...). 2483Setting this to 0 will disable the delay. 2484Default is 2 seconds. 2485.It Cd options VM86 2486Include support for virtual 8086 mode, used by 2487.Tn DOS 2488emulators and X servers to run BIOS code, e.g., for some VESA routines. 2489.It Cd options USER_LDT 2490Include i386-specific system calls for modifying the local descriptor table, 2491used by Windows emulators. 2492.It Cd options PAE 2493Enable 2494.Tn PAE (Physical Address Extension) 2495mode. 2496.Tn PAE 2497permits up to 36 bits physical addressing (64GB of physical memory), and 2498turns physical addresses to 64 bits entities in the memory management 2499subsystem. 2500Userland virtual address space remains at 32 bits (4GB). 2501.Tn PAE 2502mode is required to enable the 2503.Tn NX/XD (No-eXecute/eXecute Disable) 2504bit for pages, which allows marking certain ones as not being executable. 2505Any attempt to execute code from such a page will raise an exception. 2506.It Cd options REALBASEMEM=integer 2507Overrides the base memory size passed in from the boot block. 2508(Value given in kilobytes.) 2509Use this option only if the boot block reports the size incorrectly. 2510(Note that some 2511.Tn BIOS Ns es 2512put the extended 2513.Tn BIOS 2514data area at the top of base memory, and therefore report a smaller 2515base memory size to prevent programs overwriting it. 2516This is correct behavior, and you should not use the 2517.Em REALBASEMEM 2518option to access this memory). 2519.It Cd options REALEXTMEM=integer 2520Overrides the extended memory size passed in from the boot block. 2521(Value given in kilobytes. 2522Extended memory does not include the first megabyte.) 2523Use this option only if the boot block reports the size incorrectly. 2524.It Cd options CYRIX_CACHE_WORKS 2525Relevant only to the Cyrix 486DLC CPU. 2526This option is used to turn on the cache in hold-flush mode. 2527It is not turned on by default because it is known to have problems in 2528certain motherboard implementations. 2529.It Cd options CYRIX_CACHE_REALLY_WORKS 2530Relevant only to the Cyrix 486DLC CPU. 2531This option is used to turn on the cache in write-back mode. 2532It is not turned on by default because it is known to have problems in 2533certain motherboard implementations. 2534In order for this option to take effect, option 2535.Em CYRIX_CACHE_WORKS 2536must also be specified. 2537.It Cd options PCIBIOS 2538Enable support for initializing the 2539.Tn PCI 2540bus using information from the 2541.Tn BIOS . 2542See 2543.Xr pcibios 4 2544for details. 2545.It Cd options MTRR 2546Include support for accessing MTRR registers from user-space. 2547See 2548.Xr i386_get_mtrr 2 . 2549.It Cd options BEEP_ONHALT 2550Make the system speaker emit several beeps when it is completely safe to 2551power down the computer after a 2552.Xr halt 8 2553command. 2554Requires 2555.Xr sysbeep 4 2556support. 2557.It Cd options BEEP_ONHALT_COUNT=times 2558Number of times to beep the speaker when 2559.Cd options BEEP_ONHALT 2560is enabled. 2561Defaults to 3. 2562.It Cd options BEEP_ONHALT_PITCH=hz 2563The tone frequency used when 2564.Cd options BEEP_ONHALT 2565option, in hertz. 2566Defaults to 1500. 2567.It Cd options BEEP_ONHALT_PERIOD=msecs 2568The duration of each beep when 2569.Cd options BEEP_ONHALT 2570is enabled, in milliseconds. 2571Defaults to 250. 2572.It Cd options MULTIBOOT 2573Makes the kernel Multiboot-compliant, allowing it to be booted through 2574a Multiboot-compliant boot manager such as GRUB. 2575See 2576.Xr multiboot 8 2577for more information. 2578.It Cd options SPLASHSCREEN 2579Display a splash screen during boot. 2580.It Cd options SPLASHSCREEN_PROGRESS 2581Display a progress bar at the splash screen during boot. 2582This option requires 2583.Em SPLASHSCREEN . 2584.El 2585.Ss isa-specific Options 2586Options specific to 2587.Xr isa 4 2588busses. 2589.Bl -ohang 2590.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2591Control the section of IO bus space used for PCMCIA bus space mapping. 2592Ideally the probed defaults are satisfactory, however in practice 2593that is not always the case. 2594See 2595.Xr pcmcia 4 2596for details. 2597.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2598Controls the allowable interrupts that may be used for 2599.Tn PCMCIA 2600devices. 2601This mask is a logical-or of power-of-2s of allowable interrupts: 2602.Bd -literal -offset 04n 2603.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2604 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2605 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2606 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2607 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2608.Ed 2609.It Cd options PCKBC_CNATTACH_SELFTEST 2610Perform a self test of the keyboard controller before attaching it as a 2611console. 2612This might be necessary on machines where we boot on cold iron, and 2613pckbc refuses to talk until we request a self test. 2614Currently only the netwinder port uses it. 2615.It Cd options PCKBD_CNATTACH_MAY_FAIL 2616If this option is set the PS/2 keyboard will not be used as the console 2617if it cannot be found during boot. 2618This allows other keyboards, like USB, to be the console keyboard. 2619.It Cd options PCKBD_LAYOUT=layout 2620Sets the default keyboard layout, see 2621.Xr pckbd 4 . 2622.El 2623.Ss m68k-specific Options 2624.Bl -ohang 2625.It Cd options FPU_EMULATE 2626Include support for MC68881/MC68882 emulator. 2627.It Cd options FPSP 2628Include support for 68040 floating point. 2629.It Cd options M68020,M68030,M68040,M68060 2630Include support for a specific 2631.Tn CPU , 2632at least one (the one you are using) should be specified. 2633.It Cd options M060SP 2634Include software support for 68060. 2635This provides emulation of unimplemented 2636integer instructions as well as emulation of unimplemented floating point 2637instructions and data types and software support for floating point traps. 2638.El 2639.Ss powerpc-specific Options (OEA Only) 2640.Bl -ohang 2641.It Cd options PMAP_MEMLIMIT=value 2642Limit the amount of memory seen by the kernel to 2643.Ar value 2644bytes. 2645.It Cd options PTEGCOUNT=value 2646Specify the size of the page table as 2647.Ar value 2648PTE groups. 2649Normally, one PTEG is allocated per physical page frame. 2650.El 2651.Ss sparc-specific Options 2652.Bl -ohang 2653.It Cd options AUDIO_DEBUG 2654Enable simple event debugging of the logging of the 2655.Xr audio 4 2656device. 2657.It Cd options BLINK 2658Enable blinking of LED. 2659Blink rate is full cycle every N seconds for 2660N \*[Lt] then current load average. 2661See 2662.Xr getloadavg 3 . 2663.\" .It Cd options COLORFONT_CACHE 2664.\" What does this do? 2665.It Cd options COUNT_SW_LEFTOVERS 2666Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2667sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2668variables accessible from 2669.Xr ddb 4 . 2670See 2671.Xr sw 4 . 2672.It Cd options DEBUG_ALIGN 2673Adds debugging messages calls when user-requested alignment fault 2674handling happens. 2675.It Cd options DEBUG_EMUL 2676Adds debugging messages calls for emulated floating point and 2677alignment fixing operations. 2678.It Cd options DEBUG_SVR4 2679Prints registers messages calls for emulated SVR4 getcontext and 2680setcontext operations. 2681See 2682.Em options COMPAT_SVR4 . 2683.It Cd options EXTREME_DEBUG 2684Adds debugging functions callable from 2685.Xr ddb 4 . 2686The debug_pagetables, test_region and print_fe_map 2687functions print information about page tables for the SUN4M 2688platforms only. 2689.It Cd options EXTREME_EXTREME_DEBUG 2690Adds extra info to 2691.Em options EXTREME_DEBUG . 2692.It Cd options FPU_CONTEXT 2693Make 2694.Em options COMPAT_SVR4 2695getcontext and setcontext include floating point registers. 2696.It Cd options MAGMA_DEBUG 2697Adds debugging messages to the 2698.Xr magma 4 2699device. 2700.It Cd options RASTERCONS_FULLSCREEN 2701Use the entire screen for the console. 2702.It Cd options RASTERCONS_SMALLFONT 2703Use the Fixed font on the console, instead of the normal font. 2704.It Cd options SUN4 2705Support sun4 class machines. 2706.It Cd options SUN4C 2707Support sun4c class machines. 2708.It Cd options SUN4M 2709Support sun4m class machines. 2710.It Cd options SUN4_MMU3L 2711.\" XXX ??? 2712Enable support for sun4 3-level MMU machines. 2713.It Cd options V9 2714Enable SPARC V9 assembler in 2715.Xr ddb 4 . 2716.El 2717.Ss sparc64-specific Options 2718.Bl -ohang 2719.It Cd options AUDIO_DEBUG 2720Enable simple event debugging of the logging of the 2721.Xr audio 4 2722device. 2723.It Cd options BLINK 2724Enable blinking of LED. 2725Blink rate is full cycle every N seconds for 2726N \*[Lt] then current load average. 2727See 2728.Xr getloadavg 3 . 2729.El 2730.Ss x68k-specific Options 2731.Bl -ohang 2732.It Cd options EXTENDED_MEMORY 2733Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2734.It Cd options JUPITER 2735Include support for Jupiter-X MPU accelerator 2736.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2737Use the built-in serial port as the system-console. 2738Speed is specified in bps, defaults to 9600. 2739.It Cd options ITE_KERNEL_ATTR=value 2740Set the kernel message attribute for ITE. 2741Value, an integer, is a logical or of the following values: 2742.Bl -tag -width 4n -compact -offset indent 2743.It 1 2744color inversed 2745.It 2 2746underlined 2747.It 4 2748bolded 2749.El 2750.El 2751.\" The following requests should be uncommented and used where appropriate. 2752.\" .Sh FILES 2753.\" .Sh EXAMPLES 2754.Sh SEE ALSO 2755.Xr config 1 , 2756.Xr gdb 1 , 2757.Xr ktrace 1 , 2758.Xr pmc 1 , 2759.Xr quota 1 , 2760.Xr vndcompress 1 , 2761.Xr gettimeofday 2 , 2762.Xr i386_get_mtrr 2 , 2763.Xr i386_iopl 2 , 2764.Xr msgctl 2 , 2765.Xr msgget 2 , 2766.Xr msgrcv 2 , 2767.Xr msgsnd 2 , 2768.Xr ntp_adjtime 2 , 2769.Xr ntp_gettime 2 , 2770.Xr reboot 2 , 2771.Xr semctl 2 , 2772.Xr semget 2 , 2773.Xr semop 2 , 2774.Xr shmat 2 , 2775.Xr shmctl 2 , 2776.Xr shmdt 2 , 2777.Xr shmget 2 , 2778.Xr sysctl 3 , 2779.Xr apm 4 , 2780.Xr ddb 4 , 2781.Xr inet 4 , 2782.Xr iso 4 , 2783.Xr md 4 , 2784.Xr pcibios 4 , 2785.Xr pcmcia 4 , 2786.Xr ppp 4 , 2787.Xr userconf 4 , 2788.Xr vnd 4 , 2789.Xr wscons 4 , 2790.Xr config 5 , 2791.Xr edquota 8 , 2792.Xr init 8 , 2793.Xr mdsetimage 8 , 2794.Xr mount_cd9660 8 , 2795.Xr mount_fdesc 8 , 2796.Xr mount_kernfs 8 , 2797.Xr mount_lfs 8 , 2798.Xr mount_mfs 8 , 2799.Xr mount_msdos 8 , 2800.Xr mount_nfs 8 , 2801.Xr mount_ntfs 8 , 2802.Xr mount_null 8 , 2803.Xr mount_portal 8 , 2804.Xr mount_procfs 8 , 2805.Xr mount_udf 8 , 2806.Xr mount_umap 8 , 2807.Xr mount_union 8 , 2808.Xr mrouted 8 , 2809.Xr newfs_lfs 8 , 2810.Xr ntpd 8 , 2811.Xr quotaon 8 , 2812.Xr rpc.rquotad 8 , 2813.Xr sysctl 8 , 2814.Xr in_getifa 9 , 2815.Xr kernhist 9 2816.Sh HISTORY 2817The 2818.Nm 2819man page first appeared in 2820.Nx 1.3 . 2821.Sh BUGS 2822The 2823.Em EON 2824option should be a pseudo-device, and is also very fragile. 2825