====== Rebuilding the FreeBSD Kernel ======
The default kernel includes unnecessary components that can occupy memory, which is not ideal. It is better to create a customized and efficient kernel by removing unnecessary devices and features tailored to your needs.
====== Environment ======
FreeBSD 6.0
====== Create a Copy of the Default Kernel ======
■ To start, duplicate the default kernel (GENERIC) and rename it to a custom name of your choice.
You can use any name you prefer for your kernel. In this example, we'll be using MYKERNEL as our example.
# cd /usr/src/sys/i386/conf/
# cp GENERIC MYKERNEL
====== Modify MYKERNEL ======
#
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
#
# http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ../../conf/NOTES and NOTES files.
# If you are in doubt as to the purpose or necessity of a line, check first
# in NOTES.
#
# $FreeBSD: src/sys/i386/conf/GENERIC,v 1.413.2.13 2005/04/02 16:37:58 scottl Exp $
machine i386
#cpu I486_CPU
#cpu I586_CPU
cpu I686_CPU
ident MYKERNEL
# To statically compile in device wiring instead of /boot/device.hints
#hints "GENERIC.hints" # Default places to look for devices.
options SCHED_4BSD # 4BSD scheduler
options INET # InterNETworking
options INET6 # IPv6 communications protocols
options FFS # Berkeley Fast Filesystem
options SOFTUPDATES # Enable FFS soft updates support
options UFS_ACL # Support for access control lists
options UFS_DIRHASH # Improve performance on big directories
options MD_ROOT # MD is a potential root device
#options NFSCLIENT # Network Filesystem Client
#options NFSSERVER # Network Filesystem Server
#options NFS_ROOT # NFS usable as /, requires NFSCLIENT
options MSDOSFS # MSDOS Filesystem
options CD9660 # ISO 9660 Filesystem
options PROCFS # Process filesystem (requires PSEUDOFS)
options PSEUDOFS # Pseudo-filesystem framework
options GEOM_GPT # GUID Partition Tables.
options COMPAT_43 # Compatible with BSD 4.3 [KEEP THIS!]
options COMPAT_FREEBSD4 # Compatible with FreeBSD4
#options SCSI_DELAY=15000 # Delay (in ms) before probing SCSI
options KTRACE # ktrace(1) support
options SYSVSHM # SYSV-style shared memory
options SYSVMSG # SYSV-style message queues
options SYSVSEM # SYSV-style semaphores
options _KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options KBD_INSTALL_CDEV # install a CDEV entry in /dev
options AHC_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~128k to driver.
options AHD_REG_PRETTY_PRINT # Print register bitfields in debug
# output. Adds ~215k to driver.
options ADAPTIVE_GIANT # Giant mutex is adaptive.
#Quota
options QUOTA
# PPPoE
options NETGRAPH
options NETGRAPH_ETHER
options NETGRAPH_PPPOE
options NETGRAPH_SOCKET
# NAT
options IPDIVERT
# FIREWALL
#options IPFW2
options IPFIREWALL
options IPFIREWALL_VERBOSE
options IPFIREWALL_VERBOSE_LIMIT=50000
#options IPFIREWALL_DEFAULT_TO_ACCEPT
device apic # I/O APIC
# Bus support. Do not remove isa, even if you have no isa slots
device isa
#device eisa
device pci
# Floppy drives
device fdc
# ATA and ATAPI devices
device ata
device atadisk # ATA disk drives
device ataraid # ATA RAID drives
device atapicd # ATAPI CDROM drives
#device atapifd # ATAPI floppy drives
#device atapist # ATAPI tape drives
options ATA_STATIC_ID # Static device numbering
# SCSI Controllers
#device ahb # EISA AHA1742 family
#device ahc # AHA2940 and onboard AIC7xxx devices
#device ahd # AHA39320/29320 and onboard AIC79xx devices
#device amd # AMD 53C974 (Tekram DC-390(T))
#device isp # Qlogic family
#device mpt # LSI-Logic MPT-Fusion
#device ncr # NCR/Symbios Logic
#device sym # NCR/Symbios Logic (newer chipsets + those of `ncr')
#device trm # Tekram DC395U/UW/F DC315U adapters
#device adv # Advansys SCSI adapters
#device adw # Advansys wide SCSI adapters
#device aha # Adaptec 154x SCSI adapters
#device aic # Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
#device bt # Buslogic/Mylex MultiMaster SCSI adapters
#device ncv # NCR 53C500
#device nsp # Workbit Ninja SCSI-3
#device stg # TMC 18C30/18C50
# SCSI peripherals
#device scbus # SCSI bus (required for SCSI)
#device ch # SCSI media changers
#device da # Direct Access (disks)
#device sa # Sequential Access (tape etc)
#device cd # CD
#device pass # Passthrough device (direct SCSI access)
#device ses # SCSI Environmental Services (and SAF-TE)
# RAID controllers interfaced to the SCSI subsystem
#device amr # AMI MegaRAID
#device arcmsr # Areca SATA II RAID
#device asr # DPT SmartRAID V, VI and Adaptec SCSI RAID
#device ciss # Compaq Smart RAID 5*
#device dpt # DPT Smartcache III, IV - See NOTES for options
#device hptmv # Highpoint RocketRAID 182x
#device iir # Intel Integrated RAID
#device ips # IBM (Adaptec) ServeRAID
#device mly # Mylex AcceleRAID/eXtremeRAID
#device twa # 3ware 9000 series PATA/SATA RAID
# RAID controllers
#device aac # Adaptec FSA RAID
#device aacp # SCSI passthrough for aac (requires CAM)
#device ida # Compaq Smart RAID
#device mlx # Mylex DAC960 family
#device pst # Promise Supertrak SX6000
#device twe # 3ware ATA RAID
# atkbdc0 controls both the keyboard and the PS/2 mouse
device atkbdc # AT keyboard controller
device atkbd # AT keyboard
device psm # PS/2 mouse
device vga # VGA video card driver
#device splash # Splash screen and screen saver support
# syscons is the default console driver, resembling an SCO console
device sc
# Enable this for the pcvt (VT220 compatible) console driver
#device vt
#options XSERVER # support for X server on a vt console
#options FAT_CURSOR # start with block cursor
device agp # support several AGP chipsets
# Floating point support - do not disable.
device npx
# Power management support (see NOTES for more options)
#device apm
# Add suspend/resume support for the i8254.
device pmtimer
# PCCARD (PCMCIA) support
# PCMCIA and cardbus bridge support
#device cbb # cardbus (yenta) bridge
#device pccard # PC Card (16-bit) bus
#device cardbus # CardBus (32-bit) bus
# Serial (COM) ports
device sio # 8250, 16[45]50 based serial ports
# Parallel port
device ppc
device ppbus # Parallel port bus (required)
device lpt # Printer
#device plip # TCP/IP over parallel
#device ppi # Parallel port interface device
#device vpo # Requires scbus and da
# If you've got a "dumb" serial or parallel PCI card that is
# supported by the puc(4) glue driver, uncomment the following
# line to enable it (connects to the sio and/or ppc drivers):
#device puc
# PCI Ethernet NICs.
device de # DEC/Intel DC21x4x (``Tulip'')
device em # Intel PRO/1000 adapter Gigabit Ethernet Card
device ixgb # Intel PRO/10GbE Ethernet Card
device txp # 3Com 3cR990 (``Typhoon'')
device vx # 3Com 3c590, 3c595 (``Vortex'')
# PCI Ethernet NICs that use the common MII bus controller code.
# NOTE: Be sure to keep the 'device miibus' line in order to use these NICs!
device miibus # MII bus support
#device bfe # Broadcom BCM440x 10/100 Ethernet
#device bge # Broadcom BCM570xx Gigabit Ethernet
#device dc # DEC/Intel 21143 and various workalikes
#device fxp # Intel EtherExpress PRO/100B (82557, 82558)
#device lge # Level 1 LXT1001 gigabit ethernet
#device nge # NatSemi DP83820 gigabit ethernet
#device pcn # AMD Am79C97x PCI 10/100 (precedence over 'lnc')
#device re # RealTek 8139C+/8169/8169S/8110S
device rl # RealTek 8129/8139
#device sf # Adaptec AIC-6915 (``Starfire'')
#device sis # Silicon Integrated Systems SiS 900/SiS 7016
#device sk # SysKonnect SK-984x & SK-982x gigabit Ethernet
#device ste # Sundance ST201 (D-Link DFE-550TX)
#device ti # Alteon Networks Tigon I/II gigabit Ethernet
#device tl # Texas Instruments ThunderLAN
#device tx # SMC EtherPower II (83c170 ``EPIC'')
#device vge # VIA VT612x gigabit ethernet
#device vr # VIA Rhine, Rhine II
#device wb # Winbond W89C840F
#device xl # 3Com 3c90x (``Boomerang'', ``Cyclone'')
# ISA Ethernet NICs. pccard NICs included.
#device cs # Crystal Semiconductor CS89x0 NIC
# 'device ed' requires 'device miibus'
#device ed # NE[12]000, SMC Ultra, 3c503, DS8390 cards
#device ex # Intel EtherExpress Pro/10 and Pro/10+
#device ep # Etherlink III based cards
#device fe # Fujitsu MB8696x based cards
#device ie # EtherExpress 8/16, 3C507, StarLAN 10 etc.
#device lnc # NE2100, NE32-VL Lance Ethernet cards
#device sn # SMC's 9000 series of Ethernet chips
#device xe # Xircom pccard Ethernet
# ISA devices that use the old ISA shims
#device le
# Wireless NIC cards
#device wlan # 802.11 support
#device an # Aironet 4500/4800 802.11 wireless NICs.
#device awi # BayStack 660 and others
#device wi # WaveLAN/Intersil/Symbol 802.11 wireless NICs.
#device wl # Older non 802.11 Wavelan wireless NIC.
# Pseudo devices.
device loop # Network loopback
device mem # Memory and kernel memory devices
device io # I/O device
device random # Entropy device
device ether # Ethernet support
#device sl # Kernel SLIP
device ppp # Kernel PPP
device tun # Packet tunnel.
device pty # Pseudo-ttys (telnet etc)
device md # Memory "disks"
device gif # IPv6 and IPv4 tunneling
device faith # IPv6-to-IPv4 relaying (translation)
# The `bpf' device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
# Note that 'bpf' is required for DHCP.
device bpf # Berkeley packet filter
# USB support
#device uhci # UHCI PCI->USB interface
#device ohci # OHCI PCI->USB interface
#device ehci # EHCI PCI->USB interface (USB 2.0)
#device usb # USB Bus (required)
#device udbp # USB Double Bulk Pipe devices
#device ugen # Generic
#device uhid # "Human Interface Devices"
#device ukbd # Keyboard
#device ulpt # Printer
#device umass # Disks/Mass storage - Requires scbus and da
#device ums # Mouse
#device urio # Diamond Rio 500 MP3 player
#device uscanner # Scanners
# USB Ethernet, requires mii
#device aue # ADMtek USB Ethernet
#device axe # ASIX Electronics USB Ethernet
#device cdce # Generic USB over Ethernet
#device cue # CATC USB Ethernet
#device kue # Kawasaki LSI USB Ethernet
#device rue # RealTek RTL8150 USB Ethernet
# FireWire support
#device firewire # FireWire bus code
#device sbp # SCSI over FireWire (Requires scbus and da)
#device fwe # Ethernet over FireWire (non-standard!)
====== Compile & Install ======
■ Please note that the process may take quite some time.
[[http://dokuwiki.fl8.jp/doku.php/02_freebsd/99_%E3%81%9D%E3%81%AE%E4%BB%96/root%E3%81%A7%E3%83%AD%E3%82%B0%E3%82%A4%E3%83%B3%E3%81%A7%E3%81%8D%E3%81%AA%E3%81%84#シングルユーザモードでの起動|シングルユーザモード]]での作業を推奨します。
# config MYKERNEL
# cd ../../compile/MYKERNEL
# make depend
# make
# make install
====== If the New Kernel Doesn't Boot ======
■ In the event that your system fails to boot after installing your new kernel, you may need to revert back to your previous kernel. To do this, press 6 at the boot options screen during startup to access the loader menu.
Use the 'unload' command to unload the current kernel, then use the 'load' command to load the previous kernel before booting with the 'boot' command. This will allow you to revert back to your previous kernel and troubleshoot any issues with your new kernel.
unload
local /boot/kernel.old/kernel
boot
{{tag>FreeBSD}}