1.\" $NetBSD: options.4,v 1.451 2015/10/29 07:46:08 wiz 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 October 28, 2015 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.El 699.Ss File Systems 700.Bl -ohang 701.It Cd file-system FFS 702Includes code implementing the Berkeley Fast File System 703.Po Em FFS Pc . 704Most machines need this if they are not running diskless. 705.It Cd file-system EXT2FS 706Includes code implementing the Second Extended File System 707.Po Em ext2 Pc , 708revision 0 and revision 1 with the 709.Em filetype , 710.Em sparse_super 711and 712.Em large_file 713options. 714This is the most commonly used file system on the Linux operating system, 715and is provided here for compatibility. 716Some of the specific features of 717.Em ext2 718like the "behavior on errors" are not implemented. 719See 720.Xr mount_ext2fs 8 721for details. 722.It Cd file-system LFS 723.Bq Em EXPERIMENTAL 724Include the Log-structured File System 725.Po Em LFS Pc . 726See 727.Xr mount_lfs 8 728and 729.Xr newfs_lfs 8 730for details. 731.It Cd file-system MFS 732Include the Memory File System 733.Po Em MFS Pc . 734This file system stores files in swappable memory, and produces 735notable performance improvements when it is used as the file store 736for 737.Pa /tmp 738and similar file systems. 739See 740.Xr mount_mfs 8 741for details. 742.It Cd file-system NFS 743Include the client side of the Network File System 744.Pq Tn NFS 745remote file sharing protocol. 746Although the bulk of the code implementing 747.Tn NFS 748is kernel based, several user level daemons are needed for it to work. 749See 750.Xr mount_nfs 8 751for details. 752.It Cd file-system CD9660 753Includes code for the 754.Tn ISO 7559660 + Rock Ridge file system, which is the standard file system on many 756.Tn CD-ROM 757discs. 758Useful primarily if you have a 759.Tn CD-ROM 760drive. 761See 762.Xr mount_cd9660 8 763for details. 764.It Cd file-system MSDOSFS 765Includes the 766.Tn MS-DOS 767FAT file system, which is reportedly still used 768by unfortunate people who have not heard about 769.Nx . 770Also implements the 771.Tn Windows 95 772extensions to the same, which permit the use of longer, mixed case 773file names. 774See 775.Xr mount_msdos 8 776and 777.Xr fsck_msdos 8 778for details. 779.It Cd file-system NTFS 780.Bq Em EXPERIMENTAL 781Includes code for the 782.Tn Microsoft Windows NT 783file system. 784See 785.Xr mount_ntfs 8 786for details. 787.It Cd file-system FDESC 788Includes code for a file system, conventionally mounted on 789.Pa /dev/fd , 790which permits access to the per-process file descriptor space via 791special files in the file system. 792See 793.Xr mount_fdesc 8 794for details. 795Note that this facility is redundant, and thus unneeded on most 796.Nx 797systems, since the 798.Xr fd 4 799pseudo-device driver already provides identical functionality. 800On most 801.Nx 802systems, instances of 803.Xr fd 4 804are mknoded under 805.Pa /dev/fd/ 806and on 807.Pa /dev/stdin , 808.Pa /dev/stdout , 809and 810.Pa /dev/stderr . 811.It Cd file-system KERNFS 812Includes code which permits the mounting of a special file system 813(normally mounted on 814.Pa /kern ) 815in which files representing various kernel variables and parameters 816may be found. 817See 818.Xr mount_kernfs 8 819for details. 820.It Cd file-system NULLFS 821Includes code for a loopback file system. 822This permits portions of the file hierarchy to be re-mounted in other places. 823The code really exists to provide an example of a stackable file system layer. 824See 825.Xr mount_null 8 826for details. 827.It Cd file-system OVERLAY 828Includes code for a file system filter. 829This permits the overlay file system to intercept all access to an underlying 830file system. 831This file system is intended to serve as an example of a stacking file 832system which has a need to interpose itself between an underlying file 833system and all other access. 834See 835.Xr mount_overlay 8 836for details. 837.It Cd file-system PROCFS 838Includes code for a special file system (conventionally mounted on 839.Pa /proc ) 840in which the process space becomes visible in the file system. 841Among 842other things, the memory spaces of processes running on the system are 843visible as files, and signals may be sent to processes by writing to 844.Pa ctl 845files in the procfs namespace. 846See 847.Xr mount_procfs 8 848for details. 849.It Cd file-system UDF 850.Bq Em EXPERIMENTAL 851Includes code for the UDF file system commonly found on CD and DVD 852media but also on USB sticks. 853Currently supports read and write access upto UDF 2.01 and somewhat limited 854write support for UDF 2.50. 855It is marked experimental since there is no 856.Xr fsck_udf 8 . 857See 858.Xr mount_udf 8 859for details. 860.It Cd file-system UMAPFS 861Includes a loopback file system in which user and group IDs may be 862remapped -- this can be useful when mounting alien file systems with 863different UIDs and GIDs than the local system. 864See 865.Xr mount_umap 8 866for details. 867.It Cd file-system UNION 868.Bq Em EXPERIMENTAL 869Includes code for the union file system, which permits directories to 870be mounted on top of each other in such a way that both file systems 871remain visible -- this permits tricks like allowing writing (and the 872deleting of files) on a read-only file system like a 873.Tn CD-ROM 874by mounting a local writable file system on top of the read-only file system. 875See 876.Xr mount_union 8 877for details. 878.It Cd file-system CODA 879.Bq Em EXPERIMENTAL 880Includes code for the Coda file system. 881Coda is a distributed file system like NFS and AFS. 882It is freely available, like NFS, but it functions much like AFS in being a 883.Dq stateful 884file system. 885Both Coda and AFS cache files on your local machine to improve performance. 886Then Coda goes a step further than AFS by letting you access the cached 887files when there is no available network, viz. disconnected laptops and 888network outages. 889In Coda, both the client and server are outside the kernel which makes 890them easier to experiment with. 891Coda is available for several UNIX and non-UNIX platforms. 892See 893.Lk http://www.coda.cs.cmu.edu 894for more details. 895.Em NOTE : 896You also need to enable the pseudo-device, vcoda, for the Coda 897file system to work. 898.It Cd file-system SMBFS 899.Bq Em EXPERIMENTAL 900Includes code for the SMB/CIFS file system. 901See 902.Xr mount_smbfs 8 903for details. 904.Em NOTE : 905You also need to enable the pseudo-device, nsmb, for the SMB 906file system to work. 907.It Cd file-system PTYFS 908.Bq Em EXPERIMENTAL 909Includes code for a special file system (normally mounted on 910.Pa /dev/pts ) 911in which pseudo-terminal slave devices become visible in the file system. 912See 913.Xr mount_ptyfs 8 914for details. 915.It Cd file-system TMPFS 916Includes code for the efficient memory file system, normally used over 917.Pa /tmp . 918See 919.Xr mount_tmpfs 8 920for details. 921.It Cd file-system PUFFS 922Includes kernel support for the pass-to-userspace framework file system. 923It can be used to implement file system functionality in userspace. 924See 925.Xr puffs 3 926for more details. 927This enables for example sshfs: 928.Xr mount_psshfs 8 . 929.El 930.Ss File System Options 931.Bl -ohang 932.It Cd options MAGICLINKS 933Enables the expansion of special strings 934.Po 935beginning with 936.Dq @ 937.Pc 938when traversing symbolic links. 939See 940.Xr symlink 7 941for a list of supported strings. 942Note that this option only controls the enabling of this feature 943by the kernel at boot-up. 944This feature can still be manipulated with the 945.Xr sysctl 8 946command regardless of the setting of this option. 947.It Cd options NFSSERVER 948Include the server side of the 949.Em NFS 950(Network File System) remote file sharing protocol. 951Although the bulk of the code implementing 952.Em NFS 953is kernel based, several user level daemons are needed for it to 954work. 955See 956.Xr mountd 8 957and 958.Xr nfsd 8 959for details. 960.It Cd options NVNODE=integer 961This option sets the size of the cache used by the name-to-inode translation 962routines, (a.k.a. the 963.Fn namei 964cache, though called by many other names in the kernel source). 965By default, this cache has 966.Dv (NPROC + NTEXT + 100) 967entries (NPROC set as 20 + 16 * MAXUSERS and NTEXT as 80 + NPROC / 8). 968A reasonable way to derive a value of 969.Dv NVNODE , 970should you notice a large number of namei cache misses with a tool such as 971.Xr systat 1 , 972is to examine your system's current computed value with 973.Xr sysctl 8 , 974(which calls this parameter "kern.maxvnodes") and to increase this value 975until either the namei cache hit rate improves or it is determined that 976your system does not benefit substantially from an increase in the size of 977the namei cache. 978.It Cd options NAMECACHE_ENTER_REVERSE 979Causes the namei cache to always enter a reverse mapping (vnode -\*[Gt] name) 980as well as a normal one. 981Normally, this is already done for directory vnodes, to speed up the getcwd 982operation. 983This option will cause longer hash chains in the reverse cache, and thus 984slow down getcwd somewhat. 985However, it does make vnode -\*[Gt] path translations possible in some cases. 986For now, only useful if strict 987.Pa /proc/#/maps 988emulation for Linux binaries is required. 989.El 990.Ss Options for FFS/UFS File Systems 991.Bl -ohang 992.It Cd options WAPBL 993Enable 994.Dq Write Ahead Physical Block Logging file system journaling . 995This provides rapid file system consistency checking after a system outage. 996It also provides better general use performance over regular FFS. 997See also 998.Xr wapbl 4 . 999.It Cd options QUOTA 1000Enables kernel support for traditional quotas in FFS. 1001Traditional quotas store the quota information in external files and 1002require 1003.Xr quotacheck 8 1004and 1005.Xr quotaon 8 1006at boot time. 1007Traditional quotas are limited to 32-bit sizes and are at this point 1008considered a legacy feature. 1009.It Cd options QUOTA2 1010Enables kernel support for in-volume quotas in FFS. 1011The quota information is file system metadata maintained by 1012.Xr fsck 8 1013and/or WAPBL journaling. 1014MFS volumes can also use 1015.Dv QUOTA2 1016quotas; see 1017.Xr mount_mfs 8 1018for more information. 1019.It Cd options FFS_EI 1020Enable 1021.Dq Endian-Independent 1022FFS support. 1023This allows a system to mount an FFS file system created for another 1024architecture, at a small performance cost for all FFS file systems. 1025See also 1026.Xr newfs 8 , 1027.Xr fsck_ffs 8 , 1028.Xr dumpfs 8 1029for file system byte order status and manipulation. 1030.It Cd options FFS_NO_SNAPSHOT 1031Disable support for the creation of file system internal snapshot 1032of FFS file systems. 1033Maybe useful for install media kernels, small memory systems and 1034embedded systems which don't require the snapshot support. 1035.It Cd options UFS_EXTATTR 1036Enable extended attribute support for UFS1 file systems. 1037.It Cd options UFS_DIRHASH 1038Increase lookup performance by maintaining in-core hash tables 1039for large directories. 1040.El 1041.Ss Options for the LFS File System 1042.Bl -ohang 1043.\" .It Cd options LFS_KERNEL_RFW 1044.\" There is no documentation for this. (XXX) 1045.\" .It Cd options LFS_QUOTA 1046.\" Enable traditional quota support for LFS. 1047.\" (It is not clear if this works.) 1048.\" .It Cd options LFS_QUOTA2 1049.\" Enable modernized 64-bit quota support for LFS. 1050.\" (This does not work yet.) 1051.It Cd options LFS_EI 1052Enable 1053.Dq Endian-Independent 1054LFS support. 1055This allows (at a small performance cost) mounting an LFS file system 1056created for another architecture. 1057.\" .It Cd options LFS_EXTATTR 1058.\" Enable extended attribute support for LFS. 1059.\" (It is not clear if this works.) 1060.It Cd options LFS_DIRHASH 1061Increase lookup performance by maintaining in-core hash tables 1062for large directories. 1063.El 1064.Ss Options for the ext2fs File System 1065.Bl -ohang 1066.It Cd options EXT2FS_SYSTEM_FLAGS 1067This option changes the behavior of the APPEND and IMMUTABLE flags 1068for a file on an 1069.Em ext2 1070file system. 1071Without this option, the superuser or owner of the file can 1072set and clear them. 1073With this option, only the superuser can set them, and 1074they can't be cleared if the securelevel is greater than 0. 1075See also 1076.Xr chflags 1 1077and 1078.Xr secmodel_securelevel 9 . 1079.El 1080.Ss Options for the NFS File System 1081.Bl -ohang 1082.It Cd options NFS_BOOT_BOOTP 1083Enable use of the BOOTP protocol (RFCs 951 and 1048) to get configuration 1084information if NFS is used to mount the root file system. 1085See 1086.Xr diskless 8 1087for details. 1088.It Cd options NFS_BOOT_BOOTSTATIC 1089Enable use of static values defined as 1090.Dq NFS_BOOTSTATIC_MYIP , 1091.Dq NFS_BOOTSTATIC_GWIP , 1092.Dq NFS_BOOTSTATIC_SERVADDR , 1093and 1094.Dq NFS_BOOTSTATIC_SERVER 1095in kernel options to get configuration information 1096if NFS is used to mount the root file system. 1097.It Cd options NFS_BOOT_DHCP 1098Same as 1099.Dq NFS_BOOT_BOOTP , 1100but use the DHCP extensions to the 1101BOOTP protocol (RFC 1541). 1102.It Cd options NFS_BOOT_BOOTP_REQFILE 1103Specifies the string sent in the bp_file field of the BOOTP/DHCP 1104request packet. 1105.It Cd options NFS_BOOT_BOOTPARAM 1106Enable use of the BOOTPARAM protocol, consisting of RARP and 1107BOOTPARAM RPC, to get configuration information if NFS 1108is used to mount the root file system. 1109See 1110.Xr diskless 8 1111for details. 1112.It Cd options NFS_BOOT_RWSIZE=value 1113Set the initial NFS read and write sizes for diskless-boot requests. 1114The normal default is 8Kbytes. 1115This option provides a way to lower the value (e.g., to 1024 bytes) 1116as a workaround for buggy network interface cards or boot PROMs. 1117Once booted, the read and write request sizes can be increased by 1118remounting the file system. 1119See 1120.Xr mount_nfs 8 1121for details. 1122.It Cd options NFS_V2_ONLY 1123Reduce the size of the NFS client code by omitting code that's only required 1124for NFSv3 and NQNFS support, leaving only that code required to use NFSv2 1125servers. 1126.El 1127.Ss Buffer queue strategy options 1128The following options enable alternative buffer queue strategies. 1129.Bl -ohang 1130.It Cd options BUFQ_READPRIO 1131Enable experimental buffer queue strategy for disk I/O. 1132In the default strategy, outstanding disk requests are ordered by 1133sector number and sent to the disk, regardless of whether the 1134operation is a read or write; this option gives priority to issuing 1135read requests over write requests. 1136Although requests may therefore be issued out of sector-order, causing 1137more seeks and thus lower overall throughput, interactive system 1138responsiveness under heavy disk I/O load may be improved, as processes 1139blocking on disk reads are serviced sooner (file writes typically 1140don't cause applications to block). 1141The performance effect varies greatly depending on the hardware, drive 1142firmware, file system configuration, workload, and desired performance 1143trade-off. 1144Systems using drive write-cache (most modern IDE disks, by default) 1145are unlikely to benefit and may well suffer; such disks acknowledge 1146writes very quickly, and optimize them internally according to 1147physical layout. 1148Giving these disks as many requests to work with as possible (the 1149standard strategy) will typically produce the best results, especially 1150if the drive has a large cache; the drive will silently complete 1151writes from cache as it seeks for reads. 1152Disks that support a large number of concurrent tagged requests (SCSI 1153disks and many hardware RAID controllers) expose this internal 1154scheduling with tagged responses, and don't block for reads; such 1155disks may not see a noticeable difference with either strategy. 1156However, if IDE disks are run with write-cache disabled for safety, 1157writes are not acknowledged until actually completed, and only one 1158request can be outstanding; a large number of small writes in one 1159locality can keep the disk busy, starving reads elsewhere on the disk. 1160Such systems are likely to see the most benefit from this option. 1161Finally, the performance interaction of this option with ffs soft 1162dependencies can be subtle, as that mechanism can drastically alter 1163the workload for file system metadata writes. 1164.It Cd options BUFQ_PRIOCSCAN 1165Enable another buffer queue strategy for disk I/O, per-priority cyclical scan. 1166.It Cd options NEW_BUFQ_STRATEGY 1167Synonym of 1168.Em BUFQ_READPRIO . 1169.El 1170.Ss Miscellaneous Options 1171.Bl -ohang 1172.It Cd options CPU_UCODE 1173Support cpu microcode loading via 1174.Xr cpuctl 8 . 1175.It Cd options MEMORY_DISK_DYNAMIC 1176This option makes the 1177.Xr md 4 1178.Tn RAM 1179disk size dynamically sized. 1180It is incompatible with 1181.Xr mdsetimage 8 . 1182.It Cd options MEMORY_DISK_HOOKS 1183This option allows for some machine dependent functions to be called when 1184the 1185.Xr md 4 1186.Tn RAM 1187disk driver is configured. 1188This can result in automatically loading a 1189.Tn RAM 1190disk from floppy on open (among other things). 1191.It Cd options MEMORY_DISK_IS_ROOT 1192Forces the 1193.Xr md 4 1194.Tn RAM 1195disk to be the root device. 1196This can only be overridden when 1197the kernel is booted in the 'ask-for-root' mode. 1198.It Cd options MEMORY_DISK_ROOT_SIZE=integer 1199Allocates the given number of 512 byte blocks as memory for the 1200.Xr md 4 1201.Tn RAM 1202disk, to be populated with 1203.Xr mdsetimage 8 . 1204.It Cd options MEMORY_DISK_SERVER=0 1205Do not include the interface to a userland memory disk server process. 1206Per default, this option is set to 1, including the support code. 1207Useful for install media kernels. 1208.It Cd options MEMORY_DISK_RBFLAGS=value 1209This option sets the 1210.Xr reboot 2 1211flags used when booting with a memory disk as root file system. 1212Possible values include 1213.Dv RB_AUTOBOOT 1214(boot in the usual fashion - default value), and 1215.Dv RB_SINGLE 1216(boot in single-user mode). 1217.It Cd options MODULAR 1218Enables the framework for kernel modules (see 1219.Xr module 7 ) . 1220.It Cd options MODULAR_DEFAULT_AUTOLOAD 1221Enables the autoloading of kernel modules by default. 1222This sets the default value of the 1223.Em kern.module.autoload 1224.Xr sysctl 3 1225variable which may be changed at run time. 1226.It Cd options VND_COMPRESSION 1227Enables the 1228.Xr vnd 4 1229driver to also handle compressed images. 1230See 1231.Xr vndcompress 1 , 1232.Xr vnd 4 1233and 1234.Xr vnconfig 8 1235for more information. 1236.It Cd options SPLDEBUG 1237Help the kernel programmer find bugs related to the interrupt priority 1238level. 1239When 1240.Fn spllower 1241or 1242.Fn splraise 1243changes the current CPU's interrupt priority level to or from 1244.Dv IPL_HIGH , 1245record a backtrace. 1246Read 1247.Xr return_address 9 1248for caveats about collecting backtraces. 1249This feature is experimental, and it is only available on i386. 1250See 1251.Pa sys/kern/subr_spldebug.c . 1252.It Cd options TFTPROOT 1253Download the root memory disk through TFTP at root mount time. 1254This enables the use of a root 1255.Tn RAM 1256disk without requiring it to be embedded in the kernel using 1257.Xr mdsetimage 8 . 1258The 1259.Tn RAM 1260disk name is obtained using DHCP's filename parameter. 1261This option requires 1262.Em MEMORY_DISK_HOOKS , 1263.Em MEMORY_DISK_DYNAMIC , 1264and 1265.Em MEMORY_DISK_IS_ROOT . 1266It is incompatible with 1267.Em MEMORY_DISK_ROOT_SIZE . 1268.It Cd options HZ=integer 1269On ports that support it, set the system clock frequency (see 1270.Xr hz 9 ) 1271to the supplied value. 1272Handle with care. 1273.It Cd options NTP 1274Turns on in-kernel precision timekeeping support used by software 1275implementing 1276.Em NTP 1277(Network Time Protocol, RFC 1305). 1278The 1279.Em NTP 1280option adds an in-kernel Phase-Locked Loop (PLL) for normal 1281.Em NTP 1282operation, and a Frequency-Locked Loop (FLL) for intermittently-connected 1283operation. 1284.Xr ntpd 8 1285will employ a user-level PLL when kernel support is unavailable, 1286but the in-kernel version has lower latency and more precision, and 1287so typically keeps much better time. 1288.Pp 1289The interface to the kernel 1290.Em NTP 1291support is provided by the 1292.Xr ntp_adjtime 2 1293and 1294.Xr ntp_gettime 2 1295system calls, which are intended for use by 1296.Xr ntpd 8 1297and are enabled by the option. 1298On systems with sub-microsecond resolution timers, or where (HZ/100000) 1299is not an integer, the 1300.Em NTP 1301option also enables extended-precision arithmetic to keep track of 1302fractional clock ticks at NTP time-format precision. 1303.It Cd options PPS_SYNC 1304This option enables a kernel serial line discipline for receiving time 1305phase signals from an external reference clock such as a radio clock. 1306.Po 1307The 1308.Em NTP 1309option (which see) must be on if the 1310.Em PPS_SYNC 1311option is used 1312.Pc . 1313Some reference clocks generate a Pulse Per Second (PPS) signal in 1314phase with their time source. 1315The 1316.Em PPS 1317line discipline receives this signal on either the data leads 1318or the DCD control lead of a serial port. 1319.Pp 1320.Em NTP 1321uses the PPS signal to discipline the local clock oscillator to a high 1322degree of precision (typically less than 50 microseconds in time and 13230.1 ppm in accuracy). 1324.Em PPS 1325can also generate a serial output pulse when the system receives a PPS 1326interrupt. 1327This can be used to measure the system interrupt latency and thus calibrate 1328.Em NTP 1329to account for it. 1330Using 1331.Em PPS 1332usually requires a gadget box 1333to convert from 1334.Tn TTL 1335to 1336.Tn RS-232 1337signal levels. 1338The gadget box and PPS are described in more detail in the HTML documentation 1339for 1340.Xr ntpd 8 1341in 1342.Pa /usr/share/doc/html/ntp . 1343.Pp 1344.Nx 1345currently supports this option in 1346.Xr com 4 1347and 1348.Xr zsc 4 . 1349.It Cd options SETUIDSCRIPTS 1350Allows scripts with the setuid bit set to execute as the effective 1351user rather than the real user, just like binary executables. 1352.Pp 1353.Em NOTE : 1354Using this option will also enable 1355.Em options FDSCRIPTS 1356.It Cd options FDSCRIPTS 1357Allows execution of scripts with the execute bit set, but not the 1358read bit, by opening the file and passing the file descriptor to 1359the shell, rather than the filename. 1360.Pp 1361.Em NOTE : 1362Execute only (non-readable) scripts will have 1363.Va argv[0] 1364set to 1365.Pa /dev/fd/* . 1366What this option allows as far as security is 1367concerned, is the ability to safely ensure that the correct script 1368is run by the interpreter, as it is passed as an already open file. 1369.It Cd options RTC_OFFSET=integer 1370The kernel (and typically the hardware battery backed-up clock on 1371those machines that have one) keeps time in 1372.Em UTC 1373(Universal Coordinated Time, once known as 1374.Em GMT , 1375or Greenwich Mean Time) 1376and not in the time of the local time zone. 1377The 1378.Em RTC_OFFSET 1379option is used on some ports (such as the i386) to tell the kernel 1380that the hardware clock is offset from 1381.Em UTC 1382by the specified number of minutes. 1383This is typically used when a machine boots several operating 1384systems and one of them wants the hardware clock to run in the 1385local time zone and not in 1386.Em UTC , 1387e.g. 1388.Em RTC_OFFSET=300 1389means 1390the hardware clock is set to US Eastern Time (300 minutes behind 1391.Em UTC ) , 1392and not 1393.Em UTC . 1394(Note: 1395.Em RTC_OFFSET 1396is used to initialize a kernel variable named 1397.Va rtc_offset 1398which is the source actually used to determine the clock offset, and 1399which may be accessed via the kern.rtc_offset sysctl variable. 1400See 1401.Xr sysctl 8 1402and 1403.Xr sysctl 3 1404for details. 1405Since the kernel clock is initialized from the hardware clock very 1406early in the boot process, it is not possible to meaningfully change 1407.Va rtc_offset 1408in system initialization scripts. 1409Changing this value currently may only be done at kernel compile 1410time or by patching the kernel and rebooting). 1411.Pp 1412.Em NOTE : 1413Unfortunately, in many cases where the hardware clock 1414is kept in local time, it is adjusted for Daylight Savings 1415Time; this means that attempting to use 1416.Em RTC_OFFSET 1417to let 1418.Nx 1419coexist with such an operating system, like Windows, 1420would necessitate changing 1421.Em RTC_OFFSET 1422twice a year. 1423As such, this solution is imperfect. 1424.It Cd options MAXUPRC=integer 1425Sets the soft 1426.Dv RLIMIT_NPROC 1427resource limit, which specifies the maximum number of simultaneous 1428processes a user is permitted to run, for process 0; 1429this value is inherited by its child processes. 1430It defaults to 1431.Em CHILD_MAX , 1432which is currently defined to be 160. 1433Setting 1434.Em MAXUPRC 1435to a value less than 1436.Em CHILD_MAX 1437is not permitted, as this would result in a violation of the semantics of 1438.St -p1003.1-90 . 1439.It Cd options NOFILE=integer 1440Sets the soft 1441.Dv RLIMIT_NOFILE 1442resource limit, which specifies the maximum number of open 1443file descriptors for each process; 1444this value is inherited by its child processes. 1445It defaults to 1446.Em OPEN_MAX , 1447which is currently defined to be 64. 1448.It Cd options MAXFILES=integer 1449Sets the default value of the 1450.Em kern.maxfiles 1451sysctl variable, which indicates the maximum number of files that may 1452be open in the system. 1453.It Cd options DEFCORENAME=string 1454Sets the default value of the 1455.Em kern.defcorename 1456sysctl variable, otherwise it is set to 1457.Nm %n.core . 1458See 1459.Xr sysctl 8 1460and 1461.Xr sysctl 3 1462for details. 1463.It Cd options RASOPS_CLIPPING 1464Enables clipping within the 1465.Nm rasops 1466raster-console output system. 1467.Em NOTE : 1468only available on architectures that use 1469.Nm rasops 1470for console output. 1471.It Cd options RASOPS_SMALL 1472Removes optimized character writing code from the 1473.Nm rasops 1474raster-console output system. 1475.Em NOTE : 1476only available on architectures that use 1477.Nm rasops 1478for console output. 1479.It Cd options INCLUDE_CONFIG_FILE 1480Embeds the kernel config file used to define the kernel in the kernel 1481binary itself. 1482The embedded data also includes any files directly included by the config 1483file itself, e.g. 1484.Pa GENERIC.local 1485or 1486.Pa std.$MACHINE . 1487The embedded config file can be extracted from the resulting kernel with 1488.Xr config 1 1489.Fl x , 1490or by the following command: 1491.Bd -literal -offset indent 1492strings netbsd | sed -n 's/^_CFG_//p' | unvis 1493.Ed 1494.It Cd options INCLUDE_JUST_CONFIG 1495Similar to the above option, but includes just the actual config file, 1496not any included files. 1497.It Cd options PIPE_SOCKETPAIR 1498Use slower, but smaller socketpair(2)-based pipe implementation instead 1499of default faster, but bigger one. 1500Primarily useful for installation kernels. 1501.It Cd options USERCONF 1502Compiles in the in-kernel device configuration manager. 1503See 1504.Xr userconf 4 1505for details. 1506.It Cd options PERFCTRS 1507Compiles in kernel support for CPU performance-monitoring counters. 1508See 1509.Xr pmc 1 1510for details. 1511.Em NOTE : 1512not available on all architectures. 1513.It Cd options SCDEBUG_DEFAULT 1514Used with the 1515.Cd options SYSCALL_DEBUG 1516described below to choose which types of events are displayed. 1517.Pp 1518.Bl -tag -width "SCDEBUG_KERNHIST" -compact -offset indent 1519.It Dv SCDEBUG_CALLS 1520Show system call entry points. 1521.It Dv SCDEBUG_RETURNS 1522Show system call exit points. 1523.It Dv SCDEBUG_ALL 1524Show all system call requestes, including unimplemented calls. 1525.It Dv SCDEBUG_SHOWARGS 1526Show the arguments provided. 1527.It Dv SCDEBUG_KERNHIST 1528Store a restricted form of the system call debug in a kernel history 1529instead of printing it to the console. 1530This option relies upon 1531.Cd options KERNHIST . 1532.El 1533.Pp 1534The default value is 1535.Dv (SCDEBUG_CALLS|SCDEBUG_RETURNS|SCDEBUG_SHOWARGS) . 1536.It Cd options SYSCALL_DEBUG 1537Useful for debugging system call issues, usually in early single user bringup. 1538By default, writes entries to the system console for most system call events. 1539Can be configured with the 1540.Cd options SCDEBUG_DEFAULT 1541option to to use the 1542.Cd options KERNHIST 1543facility instead. 1544.It Cd options SYSCALL_STATS 1545Count the number of times each system call number is called. 1546The values can be read through the sysctl interface and displayed using 1547.Xr systat 1 . 1548.Em NOTE : 1549not yet available on all architectures. 1550.It Cd options SYSCALL_TIMES 1551Count the time spent (using 1552.Fn cpu_counter32 ) 1553in each system call. 1554.Em NOTE : 1555Using this option will also enable 1556.Cd options SYSCALL_STATS . 1557.It Cd options SYSCALL_TIMES_HASCOUNTER 1558Force use of 1559.Fn cpu_counter32 1560even if 1561.Fn cpu_hascounter 1562reports false. 1563Useful for systems where the cycle counter doesn't run at a constant rate 1564(e.g. Soekris boxes). 1565.It Cd options XSERVER_DDB 1566A supplement to XSERVER that adds support for entering 1567.Xr ddb 4 1568while in 1569.Tn X11 . 1570.It Cd options FILEASSOC 1571Support for 1572.Xr fileassoc 9 . 1573.It Cd options FILEASSOC_NHOOKS=integer 1574Number of storage slots per file for 1575.Xr fileassoc 9 . 1576Default is 4. 1577.El 1578.Ss Networking Options 1579.Bl -ohang 1580.It Cd options GATEWAY 1581Enables 1582.Em IPFORWARDING 1583(which see) 1584and (on most ports) increases the size of 1585.Em NMBCLUSTERS 1586(which see). 1587In general, 1588.Em GATEWAY 1589is used to indicate that a system should act as a router, and 1590.Em IPFORWARDING 1591is not invoked directly. 1592(Note that 1593.Em GATEWAY 1594has no impact on protocols other than 1595.Tn IP , 1596such as 1597.Tn CLNP ) . 1598.Em GATEWAY 1599option also compiles IPv4 and IPv6 fast forwarding code into the kernel. 1600.It Cd options ICMPPRINTFS 1601The 1602.Em ICMPPRINTFS 1603option will enable debugging information to be printed about 1604the 1605.Xr icmp 4 1606protocol. 1607.It Cd options IPFORWARDING=value 1608If 1609.Em value 1610is 1 this enables IP routing behavior. 1611If 1612.Em value 1613is 0 (the default), it disables it. 1614The 1615.Em GATEWAY 1616option sets this to 1 automatically. 1617With this option enabled, the machine will forward IP datagrams destined 1618for other machines between its interfaces. 1619Note that even without this option, the kernel will 1620still forward some packets (such as source routed packets) -- removing 1621.Em GATEWAY 1622and 1623.Em IPFORWARDING 1624is insufficient to stop all routing through a bastion host on a 1625firewall -- source routing is controlled independently. 1626To turn off source routing, use 1627.Em options IPFORWSRCRT=0 1628(which see). 1629Note that IP forwarding may be turned on and off independently of the 1630setting of the 1631.Em IPFORWARDING 1632option through the use of the 1633.Em net.inet.ip.forwarding 1634sysctl variable. 1635If 1636.Em net.inet.ip.forwarding 1637is 1, IP forwarding is on. 1638See 1639.Xr sysctl 8 1640and 1641.Xr sysctl 3 1642for details. 1643.It Cd options IPFORWSRCRT=value 1644If 1645.Em value 1646is set to zero, source routing of IP datagrams is turned off. 1647If 1648.Em value 1649is set to one (the default) or the option is absent, source routed IP 1650datagrams are forwarded by the machine. 1651Note that source routing of IP packets may be turned on and off 1652independently of the setting of the 1653.Em IPFORWSRCRT 1654option through the use of the 1655.Em net.inet.ip.forwsrcrt 1656sysctl variable. 1657If 1658.Em net.inet.ip.forwsrcrt 1659is 1, forwarding of source routed IP datagrams is on. 1660See 1661.Xr sysctl 8 1662and 1663.Xr sysctl 3 1664for details. 1665.It Cd options IFA_STATS 1666Tells the kernel to maintain per-address statistics on bytes sent 1667and received over (currently) Internet and AppleTalk addresses. 1668.\"This can be a fairly expensive operation, so you probably want to 1669.\"keep this disabled. 1670The option is not recommended as it degrades system stability. 1671.It Cd options IFQ_MAXLEN=value 1672Increases the allowed size of the network interface packet queues. 1673The default queue size is 50 packets, and you do not normally need 1674to increase it. 1675.It Cd options IPSELSRC 1676Includes support for source-address selection policies. 1677See 1678.Xr in_getifa 9 . 1679.It Cd options MROUTING 1680Includes support for IP multicast routers. 1681You certainly want 1682.Em INET 1683with this. 1684Multicast routing is controlled by the 1685.Xr mrouted 8 1686daemon. 1687See also option 1688.Cd PIM . 1689.It Cd options PIM 1690Includes support for Protocol Independent Multicast (PIM) routing. 1691You need 1692.Em MROUTING 1693and 1694.Em INET 1695with this. 1696Software using this can be found e.g. in 1697.Pa pkgsrc/net/xorp . 1698.It Cd options INET 1699Includes support for the 1700.Tn TCP/IP 1701protocol stack. 1702You almost certainly want this. 1703See 1704.Xr inet 4 1705for details. 1706.It Cd options INET6 1707Includes support for the 1708.Tn IPv6 1709protocol stack. 1710See 1711.Xr inet6 4 1712for details. 1713Unlike 1714.Em INET , 1715.Em INET6 1716enables multicast routing code as well. 1717This option requires 1718.Em INET 1719at this moment, but it should not. 1720.It Cd options ND6_DEBUG 1721The option sets the default value of net.inet6.icmp6.nd6_debug to 1, 1722for debugging IPv6 neighbor discovery protocol handling. 1723See 1724.Xr sysctl 3 1725for details. 1726.It Cd options IPSEC 1727Includes support for the 1728.Tn IPsec 1729protocol, using the implementation derived from 1730.Ox , 1731relying on 1732.Xr opencrypto 9 1733to carry out cryptographic operations. 1734See 1735.Xr fast_ipsec 4 1736for details. 1737.It Cd options IPSEC_DEBUG 1738Enables debugging code in 1739.Tn IPsec 1740stack. 1741See 1742.Xr ipsec 4 1743for details. 1744The 1745.Cd IPSEC 1746option includes support for 1747.Tn IPsec 1748Network Address Translator traversal (NAT-T), as described in RFCs 3947 1749and 3948. 1750This feature might be patent-encumbered in some countries. 1751.It Cd options ALTQ 1752Enabled ALTQ (Alternate Queueing). 1753For simple rate-limiting, use 1754.Xr tbrconfig 8 1755to set up the interface transmission rate. 1756To use queueing disciplines, their appropriate kernel options should also 1757be defined (documented below). 1758Queueing disciplines are managed by 1759.Xr altqd 8 . 1760See 1761.Xr altq 9 1762for details. 1763.It Cd options ALTQ_HFSC 1764Include support for ALTQ-implemented HFSC (Hierarchical Fair Service Curve) 1765module. 1766HFSC supports both link-sharing and guaranteed real-time services. 1767HFSC employs a service curve based QoS model, and its unique feature 1768is an ability to decouple delay and bandwidth allocation. 1769Requires 1770.Em ALTQ_RED 1771to use the RED queueing discipline on HFSC classes, or 1772.Em ALTQ_RIO 1773to use the RIO queueing discipline on HFSC classes. 1774This option assumes 1775.Em ALTQ . 1776.It Cd options ALTQ_PRIQ 1777Include support for ALTQ-implemented PRIQ (Priority Queueing). 1778PRIQ implements a simple priority-based queueing discipline. 1779A higher priority class is always served first. 1780Requires 1781.Em ALTQ_RED 1782to use the RED queueing discipline on HFSC classes, or 1783.Em ALTQ_RIO 1784to use the RIO queueing discipline on HFSC classes. 1785This option assumes 1786.Em ALTQ . 1787.It Cd options ALTQ_WFQ 1788Include support for ALTQ-implemented WFQ (Weighted Fair Queueing). 1789WFQ implements a weighted-round robin scheduler for a set of queues. 1790A weight can be assigned to each queue to give a different proportion 1791of the link capacity. 1792A hash function is used to map a flow to one of a set of queues. 1793This option assumes 1794.Em ALTQ . 1795.It Cd options ALTQ_FIFOQ 1796Include support for ALTQ-implemented FIFO queueing. 1797FIFOQ is a simple drop-tail FIFO (First In, First Out) queueing discipline. 1798This option assumes 1799.Em ALTQ . 1800.It Cd options ALTQ_RIO 1801Include support for ALTQ-implemented RIO (RED with In/Out). 1802The original RIO has 2 sets of RED parameters; one for in-profile 1803packets and the other for out-of-profile packets. 1804At the ingress of the network, profile meters tag packets as IN or 1805OUT based on contracted profiles for customers. 1806Inside the network, IN packets receive preferential treatment by 1807the RIO dropper. 1808ALTQ/RIO has 3 drop precedence levels defined for the Assured Forwarding 1809PHB of DiffServ (RFC 2597). 1810This option assumes 1811.Em ALTQ . 1812.It Cd options ALTQ_BLUE 1813Include support for ALTQ-implemented Blue buffer management. 1814Blue is another active buffer management mechanism. 1815This option assumes 1816.Em ALTQ . 1817.It Cd options ALTQ_FLOWVALVE 1818Include support for ALTQ-implemented Flowvalve. 1819Flowvalve is a simple implementation of a RED penalty box that identifies 1820and punishes misbehaving flows. 1821This option requires 1822.Em ALTQ_RED 1823and assumes 1824.Em ALTQ . 1825.It Cd options ALTQ_CDNR 1826Include support for ALTQ-implemented CDNR (diffserv traffic conditioner) 1827packet marking/manipulation. 1828Traffic conditioners are components to meter, mark, or drop incoming 1829packets according to some rules. 1830As opposed to queueing disciplines, traffic conditioners handle incoming 1831packets at an input interface. 1832This option assumes 1833.Em ALTQ . 1834.It Cd options ALTQ_NOPCC 1835Disables use of processor cycle counter to measure time in ALTQ. 1836This option should be defined for a non-Pentium i386 CPU which does not 1837have TSC, SMP (per-CPU counters are not in sync), or power management 1838which affects processor cycle counter. 1839This option assumes 1840.Em ALTQ . 1841.It Cd options ALTQ_IPSEC 1842Include support for IPsec in IPv4 ALTQ. 1843This option assumes 1844.Em ALTQ . 1845.It Cd options ALTQ_JOBS 1846Include support for ALTQ-implemented JoBS (Joint Buffer Management 1847and Scheduling). 1848This option assumes 1849.Em ALTQ . 1850.It Cd options ALTQ_AFMAP 1851Include support for an undocumented ALTQ feature that is used to map an IP 1852flow to an ATM VC (Virtual Circuit). 1853This option assumes 1854.Em ALTQ . 1855.It Cd options ALTQ_LOCALQ 1856Include support for ALTQ-implemented local queues. 1857Its practical use is undefined. 1858Assumes 1859.Em ALTQ . 1860.It Cd options SUBNETSARELOCAL 1861Sets default value for net.inet.ip.subnetsarelocal variable, which 1862controls whether non-directly-connected subnets of connected networks 1863are considered "local" for purposes of choosing the MSS for a TCP 1864connection. 1865This is mostly present for historic reasons and completely irrelevant if 1866you enable Path MTU discovery. 1867.It Cd options HOSTZEROBROADCAST 1868Sets default value for net.inet.ip.hostzerobroadcast variable, which 1869controls whether the zeroth host address of each connected subnet is 1870also considered a broadcast address. 1871Default value is "1", for compatibility with old systems; if this is 1872set to zero on all hosts on a subnet, you should be able to fit an extra 1873host per subnet on the 1874".0" address. 1875.It Cd options MCLSHIFT=value 1876This option is the base-2 logarithm of the size of mbuf clusters. 1877The 1878.Bx 1879networking stack keeps network packets in a linked 1880list, or chain, of kernel buffer objects called mbufs. 1881The system provides larger mbuf clusters as an optimization for 1882large packets, instead of using long chains for large packets. 1883The mbuf cluster size, 1884or 1885.Em MCLBYTES , 1886must be a power of two, and is computed as two raised to the power 1887.Em MCLSHIFT . 1888On systems with Ethernet network adapters, 1889.Em MCLSHIFT 1890is often set to 11, giving 2048-byte mbuf clusters, large enough to 1891hold a 1500-byte 1892.Tn Ethernet 1893frame in a single cluster. 1894Systems with network interfaces supporting larger frame sizes like 1895.Tn ATM , 1896.Tn FDDI , 1897or 1898.Tn HIPPI 1899may perform better with 1900.Em MCLSHIFT 1901set to 12 or 13, giving mbuf cluster sizes of 4096 and 8192 bytes, 1902respectively. 1903.It Cd options NETATALK 1904Include support for the 1905.Tn AppleTalk 1906protocol stack. 1907The kernel provides provision for the 1908.Em Datagram Delivery Protocol 1909(DDP), providing SOCK_DGRAM support and 1910.Tn AppleTalk 1911routing. 1912This stack is used by the 1913.Em NETATALK 1914package, which adds support for 1915.Tn AppleTalk 1916server services via user libraries and applications. 1917.It Cd options BLUETOOTH 1918Include support for the 1919.Tn Bluetooth 1920protocol stack. 1921See 1922.Xr bluetooth 4 1923for details. 1924.It Cd options IPNOPRIVPORTS 1925Normally, only root can bind a socket descriptor to a so-called 1926.Dq privileged 1927.Tn TCP 1928port, that is, a port number in the range 0-1023. 1929This option eliminates those checks from the kernel. 1930This can be useful if there is a desire to allow daemons without 1931privileges to bind those ports, e.g., on firewalls. 1932The security tradeoffs in doing this are subtle. 1933This option should only be used by experts. 1934.It Cd options TCP_COMPAT_42 1935.Tn TCP 1936bug compatibility with 1937.Bx 4.2 . 1938In 1939.Bx 4.2 , 1940.Tn TCP 1941sequence numbers were 32-bit signed values. 1942Modern implementations of TCP use unsigned values. 1943This option clamps the initial sequence number to start in 1944the range 2^31 rather than the full unsigned range of 2^32. 1945Also, under 1946.Bx 4.2 , 1947keepalive packets must contain at least one byte or else 1948the remote end would not respond. 1949.It Cd options TCP_DEBUG 1950Record the last 1951.Em TCP_NDEBUG 1952TCP packets with SO_DEBUG set, and decode to the console if 1953.Em tcpconsdebug 1954is set. 1955.It Cd options TCP_NDEBUG 1956Number of packets to record for 1957.Em TCP_DEBUG . 1958Defaults to 100. 1959.It Cd options TCP_SENDSPACE=value 1960.It Cd options TCP_RECVSPACE=value 1961These options set the max TCP window size to other sizes than the default. 1962The TCP window sizes can be altered via 1963.Xr sysctl 8 1964as well. 1965.It Cd options TCP_INIT_WIN=value 1966This option sets the initial TCP window size for non-local connections, 1967which is used when the transmission starts. 1968The default size is 1, but if the machine should act more aggressively, 1969the initial size can be set to some other value. 1970The initial TCP window size can be set via 1971.Xr sysctl 8 1972as well. 1973.It Cd options IPFILTER_LOG 1974This option, in conjunction with 1975.Em pseudo-device ipfilter , 1976enables logging of IP packets using IP-Filter. 1977.It Cd options IPFILTER_LOOKUP 1978This option enables the 1979IP-Filter 1980.Xr ippool 8 1981functionality to be enabled. 1982.It Cd options IPFILTER_COMPAT 1983This option enables older IP-Filter binaries to work. 1984.It Cd options IPFILTER_DEFAULT_BLOCK 1985This option sets the default policy of IP-Filter. 1986If it is set, IP-Filter will block packets by default. 1987.It Cd options BRIDGE_IPF 1988This option causes 1989.Em bridge 1990devices to use the IP and/or IPv6 filtering hooks, forming 1991a link-layer filter that uses protocol-layer rules. 1992This option assumes the presence of 1993.Em pseudo-device ipfilter . 1994.It Cd options MBUFTRACE 1995This option can help track down mbuf leaks. 1996When enabled, mbufs are tagged with the devices and protocols using them, 1997which slightly decreases network performance. 1998This additional information can be viewed with 1999.Xr netstat 1 : 2000.Dl Ic netstat Fl mssv 2001Not all devices or protocols support this option. 2002.El 2003.Ss Sysctl Related Options 2004.Bl -ohang 2005.It Cd options SYSCTL_DISALLOW_CREATE 2006Disallows the creation or deletion of nodes from the sysctl tree, as 2007well as the assigning of descriptions to nodes that lack them, by any 2008process. 2009These operations are still available to kernel sub-systems, including 2010loadable kernel modules. 2011.It Cd options SYSCTL_DISALLOW_KWRITE 2012Prevents processes from adding nodes to the sysctl tree that make 2013existing kernel memory areas writable. 2014Sections of kernel memory can still be read and new nodes that own 2015their own data may still be writable. 2016.It Cd options SYSCTL_DEBUG_SETUP 2017Causes the SYSCTL_SETUP routines to print a brief message when they 2018are invoked. 2019This is merely meant as an aid in determining the order in which 2020sections of the tree are created. 2021.It Cd options SYSCTL_DEBUG_CREATE 2022Prints a message each time 2023.Fn sysctl_create , 2024the function that adds nodes to the tree, is called. 2025.It Cd options SYSCTL_INCLUDE_DESCR 2026Causes the kernel to include short, human readable descriptions for 2027nodes in the sysctl tree. 2028The descriptions can be retrieved programmatically (see 2029.Xr sysctl 3 ) , 2030or by the sysctl binary itself (see 2031.Xr sysctl 8 ) . 2032The descriptions are meant to give an indication of the purpose and/or 2033effects of a given node's value, not replace the documentation for the 2034given subsystem as a whole. 2035.El 2036.Ss System V IPC Options 2037.Bl -ohang 2038.It Cd options SYSVMSG 2039Includes support for 2040.At V 2041style message queues. 2042See 2043.Xr msgctl 2 , 2044.Xr msgget 2 , 2045.Xr msgrcv 2 , 2046.Xr msgsnd 2 . 2047.It Cd options SYSVSEM 2048Includes support for 2049.At V 2050style semaphores. 2051See 2052.Xr semctl 2 , 2053.Xr semget 2 , 2054.Xr semop 2 . 2055.It Cd options SEMMNI=value 2056Sets the number of 2057.At V 2058style semaphore identifiers. 2059The GENERIC config file for your port will have the default. 2060.It Cd options SEMMNS=value 2061Sets the number of 2062.At V 2063style semaphores in the system. 2064The GENERIC config file for your port will have the default. 2065.It Cd options SEMUME=value 2066Sets the maximum number of undo entries per process for 2067.At V 2068style semaphores. 2069The GENERIC config file for your port will have the default. 2070.It Cd options SEMMNU=value 2071Sets the number of undo structures in the system for 2072.At V 2073style semaphores. 2074The GENERIC config file for your port will have the default. 2075.It Cd options SYSVSHM 2076Includes support for 2077.At V 2078style shared memory. 2079See 2080.Xr shmat 2 , 2081.Xr shmctl 2 , 2082.Xr shmdt 2 , 2083.Xr shmget 2 . 2084.It Cd options SHMMAXPGS=value 2085Sets the maximum number of 2086.At V 2087style shared memory pages that are available through the 2088.Xr shmget 2 2089system call. 2090Default value is 1024 on most ports. 2091See 2092.Pa /usr/include/machine/vmparam.h 2093for the default. 2094.El 2095.Ss VM Related Options 2096.Bl -ohang 2097.It Cd options NMBCLUSTERS=value 2098The number of mbuf clusters the kernel supports. 2099Mbuf clusters are MCLBYTES in size (usually 2k). 2100This is used to compute the size of the kernel VM map 2101.Em mb_map , 2102which maps mbuf clusters. 2103Default on most ports is 1024 (2048 with 2104.Dq options GATEWAY 2105). 2106See 2107.Pa /usr/include/machine/param.h 2108for exact default information. 2109Increase this value if you get 2110.Dq mclpool limit reached 2111messages. 2112.It Cd options NKMEMPAGES=value 2113.It Cd options NKMEMPAGES_MIN=value 2114.It Cd options NKMEMPAGES_MAX=value 2115Size of kernel VM map 2116.Em kmem_map , 2117in PAGE_SIZE-sized chunks (the VM page size; this value may be read 2118from the 2119.Xr sysctl 8 2120variable 2121.Em hw.pagesize 2122). 2123This VM map is used to map the kernel malloc arena. 2124The kernel attempts to auto-size this map based on the amount of 2125physical memory in the system. 2126Platform-specific code may place bounds on this computed size, 2127which may be viewed with the 2128.Xr sysctl 8 2129variable 2130.Em vm.nkmempages . 2131See 2132.Pa /usr/include/machine/param.h 2133for the default upper and lower bounds. 2134The related options 2135.Sq NKMEMPAGES_MIN 2136and 2137.Sq NKMEMPAGES_MAX 2138allow the bounds to be overridden in the kernel configuration file. 2139These options are provided in the event the computed value is 2140insufficient resulting in an 2141.Dq out of space in kmem_map 2142panic. 2143.It Cd options SB_MAX=value 2144Sets the max size in bytes that a socket buffer is allowed to occupy. 2145The default is 256k, but sometimes it needs to be increased, for example 2146when using large TCP windows. 2147This option can be changed via 2148.Xr sysctl 8 2149as well. 2150.It Cd options SOMAXKVA=value 2151Sets the maximum size of kernel virtual memory that the socket buffers 2152are allowed to use. 2153The default is 16MB, but in situations where for example large TCP 2154windows are used this value must also be increased. 2155This option can be changed via 2156.Xr sysctl 8 2157as well. 2158.It Cd options BUFCACHE=value 2159Size of the buffer cache as a percentage of total available 2160.Tn RAM . 2161Ignored if BUFPAGES is also specified. 2162.It Cd options NBUF=value 2163Sets the number of buffer headers available, i.e., the number of 2164open files that may have a buffer cache entry. 2165Each buffer header 2166requires MAXBSIZE (machine dependent, but usually 65536) bytes. 2167The default value is machine dependent, but is usually equal to the 2168value of BUFPAGES. 2169If an architecture dependent VM_MAX_KERNEL_BUF constant is defined 2170then NBUF may be reduced at run time so that the storage allocated 2171for buffer headers doesn't exceed that limit. 2172.It Cd options BUFPAGES=value 2173These options set the number of pages available for the buffer cache. 2174Their default value is a machine dependent value, often calculated as 2175between 5% and 10% of total available 2176.Tn RAM . 2177.It Cd options MAXTSIZ=bytes 2178Sets the maximum size limit of a process' text segment. 2179See 2180.Pa /usr/include/machine/vmparam.h 2181for the port-specific default. 2182.It Cd options DFLDSIZ=bytes 2183Sets the default size limit of a process' data segment, the value that 2184will be returned as the soft limit for 2185.Dv RLIMIT_DATA 2186(as returned by 2187.Xr getrlimit 2 ) . 2188See 2189.Pa /usr/include/machine/vmparam.h 2190for the port-specific default. 2191.It Cd options MAXDSIZ=bytes 2192Sets the maximum size limit of a process' data segment, the value that 2193will be returned as the hard limit for 2194.Dv RLIMIT_DATA 2195(as returned by 2196.Xr getrlimit 2 ) . 2197See 2198.Pa /usr/include/machine/vmparam.h 2199for the port-specific default. 2200.It Cd options DFLSSIZ=bytes 2201Sets the default size limit of a process' stack segment, the value that 2202will be returned as the soft limit for 2203.Dv RLIMIT_STACK 2204(as returned by 2205.Xr getrlimit 2 ) . 2206See 2207.Pa /usr/include/machine/vmparam.h 2208for the port-specific default. 2209.It Cd options MAXSSIZ=bytes 2210Sets the maximum size limit of a process' stack segment, the value that 2211will be returned as the hard limit for 2212.Dv RLIMIT_STACK 2213(as returned by 2214.Xr getrlimit 2 ) . 2215See 2216.Pa /usr/include/machine/vmparam.h 2217for the port-specific default. 2218.It Cd options DUMP_ON_PANIC=integer 2219Defaults to one. 2220If set to zero, the kernel will not dump to the dump device when 2221it panics, though dumps can still be forced via 2222.Xr ddb 4 2223with the 2224.Dq sync 2225command. 2226Note that this sets the value of the 2227.Em kern.dump_on_panic 2228.Xr sysctl 3 2229variable which may be changed at run time -- see 2230.Xr sysctl 8 2231for details. 2232.It Cd options USE_TOPDOWN_VM 2233User space memory allocations (as made by 2234.Xr mmap 2 ) 2235will be arranged in a 2236.Dq top down 2237fashion instead of the traditional 2238.Dq upwards from MAXDSIZ \&+ vm_daddr 2239method. 2240This includes the placement of 2241.Xr ld.so 1 . 2242Arranging memory in this manner allows either (or both of) the heap or 2243.Xr mmap 2 2244allocated space to grow larger than traditionally possible. 2245This option is not available on all ports, but is instead expected to be 2246offered on a port-by-port basis, after which some ports will commit to 2247using it by default. 2248See the files 2249.Pa /usr/include/uvm/uvm_param.h 2250for some implementation details, and 2251.Pa /usr/include/machine/vmparam.h 2252for port specific details including availability. 2253.It Cd options VMSWAP 2254Enable paging device/file support. 2255This option is on by default. 2256.It Cd options PDPOLICY_CLOCKPRO 2257Use CLOCK-Pro, an alternative page replace policy. 2258.El 2259.Ss Security Options 2260.Bl -ohang 2261.It Cd options INSECURE 2262Initializes the kernel security level with \-1 instead of 0. 2263This means that the system always starts in secure level \-1 mode, even when 2264running multiuser, unless the securelevel variable is set to value > \-1 in 2265.Pa /etc/rc.conf . 2266In this case the kernel security level will be raised to that value when the 2267.Pa /etc/rc.d/securelevel 2268script is run during system startup. 2269See the manual page for 2270.Xr init 8 2271for details on the implications of this. 2272The kernel secure level may manipulated by the superuser by altering the 2273.Em kern.securelevel 2274.Xr sysctl 3 2275variable (the secure level may only be lowered by a call from process ID 1, 2276i.e., 2277.Xr init 8 ) . 2278See also 2279.Xr secmodel_securelevel 9 , 2280.Xr sysctl 8 2281and 2282.Xr sysctl 3 . 2283.It Cd options VERIFIED_EXEC_FP_MD5 2284Enables support for MD5 hashes in Veriexec. 2285.It Cd options VERIFIED_EXEC_FP_SHA1 2286Enables support for SHA1 hashes in Veriexec. 2287.It Cd options VERIFIED_EXEC_FP_RMD160 2288Enables support for RMD160 hashes in Veriexec. 2289.It Cd options VERIFIED_EXEC_FP_SHA256 2290Enables support for SHA256 hashes in Veriexec. 2291.It Cd options VERIFIED_EXEC_FP_SHA384 2292Enables support for SHA384 hashes in Veriexec. 2293.It Cd options VERIFIED_EXEC_FP_SHA512 2294Enables support for SHA512 hashes in Veriexec. 2295.It Cd options PAX_MPROTECT=value 2296Enables PaX MPROTECT, 2297.Xr mprotect 2 2298restrictions from the PaX project. 2299.Pp 2300The 2301.Ar value 2302is the default value for the 2303.Em global 2304knob, see 2305.Xr sysctl 3 . 2306If 0, PaX MPROTECT will be enabled only if explicitly set on programs 2307using 2308.Xr paxctl 8 . 2309If 1, PaX MPROTECT will be enabled for all programs. 2310Programs can be exempted using 2311.Xr paxctl 8 . 2312.Pp 2313See 2314.Xr security 7 2315for more details. 2316.It Cd options PAX_SEGVGUARD=value 2317Enables PaX Segvguard. 2318.Pp 2319The 2320.Ar value 2321is the default value for the 2322.Em global 2323knob, see 2324.Xr sysctl 3 . 2325If 0, PaX Segvguard will be enabled only if explicitly set on programs 2326using 2327.Xr paxctl 8 . 2328If 1, PaX Segvguard will be enabled to all programs, and exemption can 2329be done using 2330.Xr paxctl 8 . 2331.Pp 2332See 2333.Xr security 7 2334for more details. 2335.It Cd options PAX_ASLR=value 2336Enables PaX ASLR. 2337.Pp 2338The 2339.Ar value 2340is the default value for the 2341.Em global 2342knob, see 2343.Xr sysctl 3 . 2344If 0, PaX ASLR will be enabled only if explicitly set on programs 2345using 2346.Xr paxctl 8 . 2347If 1, PaX ASLR will be enabled to all programs, and exemption can 2348be done using 2349.Xr paxctl 8 . 2350.Pp 2351See 2352.Xr security 7 2353for more details. 2354.It Cd options USER_VA0_DISABLE_DEFAULT=value 2355Sets the initial value of the flag which controls whether user programs 2356can map virtual address 0. 2357The flag can be changed at runtime by 2358.Xr sysctl 3 . 2359.El 2360.Ss amiga-specific Options 2361.Bl -ohang 2362.It Cd options BB060STUPIDROM 2363When the bootloader (which passes 2364.Tn AmigaOS 2365.Tn ROM 2366information) claims we have a 68060 2367.Tn CPU 2368without 2369.Tn FPU , 2370go look into the Processor Configuration Register (PCR) to find out. 2371You need this with 2372.Tn Amiga 2373.Tn ROM Ns s 2374up to (at least) V40.xxx (OS3.1), 2375when you boot via the bootblocks and don't have a DraCo. 2376.It Cd options IOBZCLOCK=frequency 2377The IOBlix boards come with two different serial master clocks: older ones 2378use 24 MHz, newer ones use 22.1184 MHz. 2379The driver normally assumes the latter. 2380If your board uses 24 MHz, you can recompile your kernel with 2381options IOBZCLOCK=24000000 2382or patch the kernel variable 2383.Tn iobzclock 2384to the same value. 2385.It Cd options LIMITMEM=value 2386If there, limit the part of the first memory bank used by 2387.Nx 2388to value megabytes. 2389Default is unlimited. 2390.It Cd options P5PPC68KBOARD 2391Add special support for Phase5 mixed 68k+PPC boards. 2392Currently, this only affects rebooting from 2393.Nx 2394and is only needed on 68040+PPC, not on 239568060+PPC; without this, affected machines will hang after 2396.Nx 2397has shut 2398down and will only restart after a keyboard reset or a power cycle. 2399.El 2400.Ss atari-specific Options 2401.Bl -ohang 2402.It Cd options DISKLABEL_AHDI 2403Include support for AHDI (native Atari) disklabels. 2404.It Cd options DISKLABEL_NBDA 2405Include support for 2406.Nx Ns Tn /atari 2407labels. 2408If you don't set this option, it will be set automatically. 2409.Nx Ns Tn /atari 2410will not work without it. 2411.It Cd options FALCON_SCSI 2412Include support for the 5380-SCSI configuration as found on the Falcon. 2413.It Cd options RELOC_KERNEL 2414If set, the kernel will relocate itself to TT-RAM, if possible. 2415This will give you a slightly faster system. 2416.Em Beware 2417that on some TT030 systems, 2418the system will frequently dump with MMU-faults with this option enabled. 2419.It Cd options SERCONSOLE 2420Allow the modem1-port to act as the system-console. 2421A carrier should be active on modem1 during system boot to active 2422the console functionality. 2423.It Cd options TT_SCSI 2424Include support for the 5380-SCSI configuration as found on the TT030 2425and Hades. 2426.El 2427.Ss i386-specific Options 2428.Bl -ohang 2429.It Cd options CPURESET_DELAY=value 2430Specifies the time (in millisecond) to wait before doing a hardware reset 2431in the last phase of a reboot. 2432This gives the user a chance to see error messages from the shutdown 2433operations (like NFS unmounts, buffer cache flush, etc ...). 2434Setting this to 0 will disable the delay. 2435Default is 2 seconds. 2436.It Cd options VM86 2437Include support for virtual 8086 mode, used by 2438.Tn DOS 2439emulators and X servers to run BIOS code, e.g., for some VESA routines. 2440.It Cd options USER_LDT 2441Include i386-specific system calls for modifying the local descriptor table, 2442used by Windows emulators. 2443.It Cd options PAE 2444Enable 2445.Tn PAE (Physical Address Extension) 2446mode. 2447.Tn PAE 2448permits up to 36 bits physical addressing (64GB of physical memory), and 2449turns physical addresses to 64 bits entities in the memory management 2450subsystem. 2451Userland virtual address space remains at 32 bits (4GB). 2452.Tn PAE 2453mode is required to enable the 2454.Tn NX/XD (No-eXecute/eXecute Disable) 2455bit for pages, which allows marking certain ones as not being executable. 2456Any attempt to execute code from such a page will raise an exception. 2457.It Cd options REALBASEMEM=integer 2458Overrides the base memory size passed in from the boot block. 2459(Value given in kilobytes.) 2460Use this option only if the boot block reports the size incorrectly. 2461(Note that some 2462.Tn BIOS Ns es 2463put the extended 2464.Tn BIOS 2465data area at the top of base memory, and therefore report a smaller 2466base memory size to prevent programs overwriting it. 2467This is correct behavior, and you should not use the 2468.Em REALBASEMEM 2469option to access this memory). 2470.It Cd options REALEXTMEM=integer 2471Overrides the extended memory size passed in from the boot block. 2472(Value given in kilobytes. 2473Extended memory does not include the first megabyte.) 2474Use this option only if the boot block reports the size incorrectly. 2475.It Cd options CYRIX_CACHE_WORKS 2476Relevant only to the Cyrix 486DLC CPU. 2477This option is used to turn on the cache in hold-flush mode. 2478It is not turned on by default because it is known to have problems in 2479certain motherboard implementations. 2480.It Cd options CYRIX_CACHE_REALLY_WORKS 2481Relevant only to the Cyrix 486DLC CPU. 2482This option is used to turn on the cache in write-back mode. 2483It is not turned on by default because it is known to have problems in 2484certain motherboard implementations. 2485In order for this option to take effect, option 2486.Em CYRIX_CACHE_WORKS 2487must also be specified. 2488.It Cd options PCIBIOS 2489Enable support for initializing the 2490.Tn PCI 2491bus using information from the 2492.Tn BIOS . 2493See 2494.Xr pcibios 4 2495for details. 2496.It Cd options KSTACK_CHECK_DR0 2497Detect kernel stack overflow using DR0 register. 2498This option uses DR0 register exclusively so you can't use DR0 register for 2499other purpose (e.g., hardware breakpoint) if you turn this on. 2500.It Cd options MTRR 2501Include support for accessing MTRR registers from user-space. 2502See 2503.Xr i386_get_mtrr 2 . 2504.It Cd options BEEP_ONHALT 2505Make the system speaker emit several beeps when it is completely safe to 2506power down the computer after a 2507.Xr halt 8 2508command. 2509Requires 2510.Xr sysbeep 4 2511support. 2512.It Cd options BEEP_ONHALT_COUNT=times 2513Number of times to beep the speaker when 2514.Cd options BEEP_ONHALT 2515is enabled. 2516Defaults to 3. 2517.It Cd options BEEP_ONHALT_PITCH=hz 2518The tone frequency used when 2519.Cd options BEEP_ONHALT 2520option, in hertz. 2521Defaults to 1500. 2522.It Cd options BEEP_ONHALT_PERIOD=msecs 2523The duration of each beep when 2524.Cd options BEEP_ONHALT 2525is enabled, in milliseconds. 2526Defaults to 250. 2527.It Cd options MULTIBOOT 2528Makes the kernel Multiboot-compliant, allowing it to be booted through 2529a Multiboot-compliant boot manager such as GRUB. 2530See 2531.Xr multiboot 8 2532for more information. 2533.It Cd options SPLASHSCREEN 2534Display a splash screen during boot. 2535.It Cd options SPLASHSCREEN_PROGRESS 2536Display a progress bar at the splash screen during boot. 2537This option requires 2538.Em SPLASHSCREEN . 2539.El 2540.Ss isa-specific Options 2541Options specific to 2542.Xr isa 4 2543busses. 2544.Bl -ohang 2545.It Cd options PCIC_ISA_ALLOC_IOBASE=address, PCIC_ISA_ALLOC_IOSIZE=size 2546Control the section of IO bus space used for PCMCIA bus space mapping. 2547Ideally the probed defaults are satisfactory, however in practice 2548that is not always the case. 2549See 2550.Xr pcmcia 4 2551for details. 2552.It Cd options PCIC_ISA_INTR_ALLOC_MASK=mask 2553Controls the allowable interrupts that may be used for 2554.Tn PCMCIA 2555devices. 2556This mask is a logical-or of power-of-2s of allowable interrupts: 2557.Bd -literal -offset 04n 2558.Em "IRQ Val IRQ Val IRQ Val IRQ Val" 2559 0 0x0001 4 0x0010 8 0x0100 12 0x1000 2560 1 0x0002 5 0x0020 9 0x0200 13 0x2000 2561 2 0x0004 6 0x0040 10 0x0400 14 0x4000 2562 3 0x0008 7 0x0080 11 0x0800 15 0x8000 2563.Ed 2564.It Cd options PCKBC_CNATTACH_SELFTEST 2565Perform a self test of the keyboard controller before attaching it as a 2566console. 2567This might be necessary on machines where we boot on cold iron, and 2568pckbc refuses to talk until we request a self test. 2569Currently only the netwinder port uses it. 2570.It Cd options PCKBD_CNATTACH_MAY_FAIL 2571If this option is set the PS/2 keyboard will not be used as the console 2572if it cannot be found during boot. 2573This allows other keyboards, like USB, to be the console keyboard. 2574.It Cd options PCKBD_LAYOUT=layout 2575Sets the default keyboard layout, see 2576.Xr pckbd 4 . 2577.El 2578.Ss m68k-specific Options 2579.Bl -ohang 2580.It Cd options FPU_EMULATE 2581Include support for MC68881/MC68882 emulator. 2582.It Cd options FPSP 2583Include support for 68040 floating point. 2584.It Cd options M68020,M68030,M68040,M68060 2585Include support for a specific 2586.Tn CPU , 2587at least one (the one you are using) should be specified. 2588.It Cd options M060SP 2589Include software support for 68060. 2590This provides emulation of unimplemented 2591integer instructions as well as emulation of unimplemented floating point 2592instructions and data types and software support for floating point traps. 2593.El 2594.Ss powerpc-specific Options (OEA Only) 2595.Bl -ohang 2596.It Cd options PMAP_MEMLIMIT=value 2597Limit the amount of memory seen by the kernel to 2598.Ar value 2599bytes. 2600.It Cd options PTEGCOUNT=value 2601Specify the size of the page table as 2602.Ar value 2603PTE groups. 2604Normally, one PTEG is allocated per physical page frame. 2605.El 2606.Ss sparc-specific Options 2607.Bl -ohang 2608.It Cd options AUDIO_DEBUG 2609Enable simple event debugging of the logging of the 2610.Xr audio 4 2611device. 2612.It Cd options BLINK 2613Enable blinking of LED. 2614Blink rate is full cycle every N seconds for 2615N \*[Lt] then current load average. 2616See 2617.Xr getloadavg 3 . 2618.\" .It Cd options COLORFONT_CACHE 2619.\" What does this do? 2620.It Cd options COUNT_SW_LEFTOVERS 2621Count how many times the sw SCSI device has left 3, 2, 1 and 0 in the 2622sw_3_leftover, sw_2_leftover, sw_1_leftover, and sw_0_leftover 2623variables accessible from 2624.Xr ddb 4 . 2625See 2626.Xr sw 4 . 2627.It Cd options DEBUG_ALIGN 2628Adds debugging messages calls when user-requested alignment fault 2629handling happens. 2630.It Cd options DEBUG_EMUL 2631Adds debugging messages calls for emulated floating point and 2632alignment fixing operations. 2633.It Cd options DEBUG_SVR4 2634Prints registers messages calls for emulated SVR4 getcontext and 2635setcontext operations. 2636See 2637.Em options COMPAT_SVR4 . 2638.It Cd options EXTREME_DEBUG 2639Adds debugging functions callable from 2640.Xr ddb 4 . 2641The debug_pagetables, test_region and print_fe_map 2642functions print information about page tables for the SUN4M 2643platforms only. 2644.It Cd options EXTREME_EXTREME_DEBUG 2645Adds extra info to 2646.Em options EXTREME_DEBUG . 2647.It Cd options FPU_CONTEXT 2648Make 2649.Em options COMPAT_SVR4 2650getcontext and setcontext include floating point registers. 2651.It Cd options MAGMA_DEBUG 2652Adds debugging messages to the 2653.Xr magma 4 2654device. 2655.It Cd options RASTERCONS_FULLSCREEN 2656Use the entire screen for the console. 2657.It Cd options RASTERCONS_SMALLFONT 2658Use the Fixed font on the console, instead of the normal font. 2659.It Cd options SUN4 2660Support sun4 class machines. 2661.It Cd options SUN4C 2662Support sun4c class machines. 2663.It Cd options SUN4M 2664Support sun4m class machines. 2665.It Cd options SUN4_MMU3L 2666.\" XXX ??? 2667Enable support for sun4 3-level MMU machines. 2668.It Cd options V9 2669Enable SPARC V9 assembler in 2670.Xr ddb 4 . 2671.El 2672.Ss sparc64-specific Options 2673.Bl -ohang 2674.It Cd options AUDIO_DEBUG 2675Enable simple event debugging of the logging of the 2676.Xr audio 4 2677device. 2678.It Cd options BLINK 2679Enable blinking of LED. 2680Blink rate is full cycle every N seconds for 2681N \*[Lt] then current load average. 2682See 2683.Xr getloadavg 3 . 2684.El 2685.Ss x68k-specific Options 2686.Bl -ohang 2687.It Cd options EXTENDED_MEMORY 2688Include support for extended memory, e.g., TS-6BE16 and 060turbo on-board. 2689.It Cd options JUPITER 2690Include support for Jupiter-X MPU accelerator 2691.It Cd options ZSCONSOLE,ZSCN_SPEED=value 2692Use the built-in serial port as the system-console. 2693Speed is specified in bps, defaults to 9600. 2694.It Cd options ITE_KERNEL_ATTR=value 2695Set the kernel message attribute for ITE. 2696Value, an integer, is a logical or of the following values: 2697.Bl -tag -width 4n -compact -offset indent 2698.It 1 2699color inversed 2700.It 2 2701underlined 2702.It 4 2703bolded 2704.El 2705.El 2706.\" The following requests should be uncommented and used where appropriate. 2707.\" .Sh FILES 2708.\" .Sh EXAMPLES 2709.Sh SEE ALSO 2710.Xr config 1 , 2711.Xr gdb 1 , 2712.Xr ktrace 1 , 2713.Xr pmc 1 , 2714.Xr quota 1 , 2715.Xr vndcompress 1 , 2716.Xr gettimeofday 2 , 2717.Xr i386_get_mtrr 2 , 2718.Xr i386_iopl 2 , 2719.Xr msgctl 2 , 2720.Xr msgget 2 , 2721.Xr msgrcv 2 , 2722.Xr msgsnd 2 , 2723.Xr ntp_adjtime 2 , 2724.Xr ntp_gettime 2 , 2725.Xr reboot 2 , 2726.Xr semctl 2 , 2727.Xr semget 2 , 2728.Xr semop 2 , 2729.Xr shmat 2 , 2730.Xr shmctl 2 , 2731.Xr shmdt 2 , 2732.Xr shmget 2 , 2733.Xr sysctl 3 , 2734.Xr apm 4 , 2735.Xr ddb 4 , 2736.Xr inet 4 , 2737.Xr iso 4 , 2738.Xr md 4 , 2739.Xr pcibios 4 , 2740.Xr pcmcia 4 , 2741.Xr ppp 4 , 2742.Xr userconf 4 , 2743.Xr vnd 4 , 2744.Xr wscons 4 , 2745.Xr config 5 , 2746.Xr edquota 8 , 2747.Xr init 8 , 2748.Xr mdsetimage 8 , 2749.Xr mount_cd9660 8 , 2750.Xr mount_fdesc 8 , 2751.Xr mount_kernfs 8 , 2752.Xr mount_lfs 8 , 2753.Xr mount_mfs 8 , 2754.Xr mount_msdos 8 , 2755.Xr mount_nfs 8 , 2756.Xr mount_ntfs 8 , 2757.Xr mount_null 8 , 2758.Xr mount_portal 8 , 2759.Xr mount_procfs 8 , 2760.Xr mount_udf 8 , 2761.Xr mount_umap 8 , 2762.Xr mount_union 8 , 2763.Xr mrouted 8 , 2764.Xr newfs_lfs 8 , 2765.Xr ntpd 8 , 2766.Xr quotaon 8 , 2767.Xr rpc.rquotad 8 , 2768.Xr sysctl 8 , 2769.Xr in_getifa 9 , 2770.Xr kernhist 9 2771.Sh HISTORY 2772The 2773.Nm 2774man page first appeared in 2775.Nx 1.3 . 2776.Sh BUGS 2777The 2778.Em EON 2779option should be a pseudo-device, and is also very fragile. 2780