FreeBSD编译内核详解

FreeBSD编译内核详解

作者: heiyeluren
: 5415735 (Linux/FreeBSD安装维护群)
日期: 2004/9/2
-- 特别感谢好友阿南,本文在他的耐心指导下才产生 --

以前老听说编译内核,觉得特别神气,呵呵,特别是像FreeBSD这样自由开发的操作系统,简直是非常好,能够自己定制内核,想怎么弄就怎么弄,呵呵,能够提升速度,还能够保证安全稳定,所以我就试一试怎么定制内核. (我也是新手，如果文章出现错误，请指正！)

我所用的FreeBSD是5.2.1版,现在是比较新的了,我一看我的内核文件大小:

# ls -l /boot/kernel/kernel
-r-xr-xr-x 1 root wheel 5940286 Feb 24 2004 /boot/kernel.bak/kernel

看来不小呀，5M多，呵呵，我要把它编成 3M左右,呵呵，begin...

一、安装内核源代码
要编译内核，首先必须保证内核的源代码在，我们看看我们的系统有没有安装：

# ls /usr/src/sys
ls: /usr/src/sys: No such file or directory

证明我们并没有安装内核源代码，好，我们就安装它。内核源代码默认是安装在了/usr/src/sys目录下的，如果不存在该目录，那么证明你没

有安装源代码。
我们先把我们的FreeBSD的安装光盘放进光驱，然后在FreeBSD下执行以root身份执行/stand/sysinstall， 选择Configure，接着是

Distributions， 下来src， 最后sys,回车后能开始安装了，一般只要几分钟就能安装好，装好了你就能查看该文件夹：

# ls /usr/src/sys
Makefile ddb libkern netkey pci
alpha dev modules netnatm posix4
amd64 fs net netncp powerpc
arm geom net80211 netsmb rpc
boot gnu netatalk nfs security
cam i386 netatm nfs4client sparc64
coda i4b netgraph nfsclient sys
compat ia64 netinet nfsserver tools
conf isa netinet6 opencrypto ufs
contrib isofs netipsec pc98 vm
crypto kern netipx pccard

源代码安装好后，我们就可以开始我们的配置内核只旅啦。

二、配置内核文件
其实我们编译内核的关键就是配置内核文件，内核配置文件的目录是在 /usr/src/sys/i386/conf 下，我们进入改目录：

# cd /usr/src/sys/i386/conf
# ls
GENERIC GENERIC.hints NOTES PAE
Makefile OLDCARD gethints.awk

内核配置文件就是GENERIC,我们要配置的就是它,配置包括要开启那些硬件支持，IPv6支持，网卡等等。为了防止我们配置文件配置后有问题，

我们先把它备份一下：

# cp GENERIC GENERIC.bak

然后我们就用任一编辑器打开该文件，可以使用vi，或者ee打开，我为了方便，就使用ee来打开：

# ee GENERIC

打开后就有类似:

# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:

的内容，前面有"#"代表该内容或者选项是注释，那么假如我们要去掉什么选项，就可以在前面加上"#",当然你不需要的选项你也可删除，但是

我推荐不需要的选项在前面加"#"。

关于配置文件详细的修改建议参考FreeBSD中文手册关于内核配置选项的详细说明：
http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/books/handbook/kernelconfig-config.html

我的配置文件是这么修改的，详细我就不说明了,请查看上面的配置文件参考，应该适合大部分没有ISA,SCSI,RAID等设备的机器。

GENERIC内核配置文件配置：

#########################################################################################
#
# 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 1.394.2.3 2004/01/26 19:42:11 nectar Exp $

machinei386
#cpuI486_CPU
#cpuI586_CPU
cpuI686_CPU
identGENERIC

#To statically compile in device wiring instead of /boot/device.hints
#hints"GENERIC.hints"#Default places to look for devices.

#makeoptionsDEBUG=-g#Build kernel with gdb(1) debug symbols

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 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 PFIL_HOOKS# pfil(9) framework

# Debugging for use in -current
#options DDB#Enable the kernel debugger
#options INVARIANTS#Enable calls of extra sanity checking
#options INVARIANT_SUPPORT#Extra sanity checks of internal structures, required by INVARIANTS
#options WITNESS#Enable checks to detect deadlocks and cycles
#options WITNESS_SKIPSPIN#Don't run witness on spinlocks for speed

# To make an SMP kernel, the next two are needed
#options SMP# Symmetric MultiProcessor Kernel
#deviceapic# I/O APIC

deviceisa
deviceeisa
devicepci

# Floppy drives
devicefdc

# ATA and ATAPI devices
deviceata
deviceatadisk# ATA disk drives
#deviceataraid# ATA RAID drives
deviceatapicd# ATAPI CDROM drives
deviceatapifd# ATAPI floppy drives
#deviceatapist# ATAPI tape drives
options ATA_STATIC_ID#Static device numbering

# SCSI Controllers
#deviceahb# EISA AHA1742 family
#deviceahc# AHA2940 and onboard AIC7xxx devices
#deviceahd# AHA39320/29320 and onboard AIC79xx devices
#deviceamd# AMD 53C974 (Tekram DC-390(T))
#deviceisp# Qlogic family
#devicempt# LSI-Logic MPT-Fusion
#devicencr# NCR/Symbios Logic
#devicesym# NCR/Symbios Logic (newer chipsets + those of `ncr')
#devicetrm# Tekram DC395U/UW/F DC315U adapters

#deviceadv# Advansys SCSI adapters
#deviceadw# Advansys wide SCSI adapters
#deviceaha# Adaptec 154x SCSI adapters
#deviceaic# Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
#devicebt# Buslogic/Mylex MultiMaster SCSI adapters

#devicencv# NCR 53C500
#devicensp# Workbit Ninja SCSI-3
#devicestg# TMC 18C30/18C50

# SCSI peripherals
devicescbus# SCSI bus (required for SCSI)
#devicech# SCSI media changers
#deviceda# Direct Access (disks)
#devicesa# Sequential Access (tape etc)
#devicecd# CD
#devicepass# Passthrough device (direct SCSI access)
#deviceses# SCSI Environmental Services (and SAF-TE)

# RAID controllers interfaced to the SCSI subsystem
#deviceamr# AMI MegaRAID
#deviceasr# DPT SmartRAID V, VI and Adaptec SCSI RAID
#deviceciss# Compaq Smart RAID 5*
#devicedpt# DPT Smartcache III, IV - See NOTES for options
#deviceiir# Intel Integrated RAID
#deviceips# IBM (Adaptec) ServeRAID
#devicemly# Mylex AcceleRAID/eXtremeRAID

# RAID controllers
#deviceaac# Adaptec FSA RAID
#deviceaacp# SCSI passthrough for aac (requires CAM)
#deviceida# Compaq Smart RAID
#devicemlx# Mylex DAC960 family
#devicepst# Promise Supertrak SX6000
#devicetwe# 3ware ATA RAID

# atkbdc0 controls both the keyboard and the PS/2 mouse
deviceatkbdc# AT keyboard controller
deviceatkbd# AT keyboard
devicepsm# PS/2 mouse

devicevga# VGA video card driver

devicesplash# Splash screen and screen saver support

# syscons is the default console driver, resembling an SCO console
devicesc

# Enable this for the pcvt (VT220 compatible) console driver
#devicevt
#options XSERVER# support for X server on a vt console
#options FAT_CURSOR# start with block cursor

deviceagp# support several AGP chipsets

# Floating point support - do not disable.
devicenpx

# Power management support (see NOTES for more options)
#deviceapm
# Add suspend/resume support for the i8254.
#devicepmtimer

# PCCARD (PCMCIA) support
# Pcmcia and cardbus bridge support
#devicecbb# cardbus (yenta) bridge
#devicepcic# ExCA ISA and PCI bridges
#devicepccard# PC Card (16-bit) bus
#devicecardbus# CardBus (32-bit) bus

# Serial (COM) ports
#devicesio# 8250, 16[45]50 based serial ports

# Parallel port
deviceppc
deviceppbus# Parallel port bus (required)
#devicelpt# Printer
deviceplip# TCP/IP over parallel
deviceppi# Parallel port interface device
#devicevpo# 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.
#devicede# DEC/Intel DC21x4x (``Tulip'')
deviceem# Intel PRO/1000 adapter Gigabit Ethernet Card
#devicetxp# 3Com 3cR990 (``Typhoon'')
#devicevx# 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!
devicemiibus# MII bus support
#devicebfe# Broadcom BCM440x 10/100 ethernet
#devicebge# Broadcom BCM570xx Gigabit Ethernet
#devicedc# DEC/Intel 21143 and various workalikes
devicefxp# Intel EtherExpress PRO/100B (82557, 82558)
#devicepcn# AMD Am79C97x PCI 10/100 (precedence over 'lnc')
#devicere# RealTek 8139C+/8169/8169S/8110S
#devicerl# RealTek 8129/8139
#devicesf# Adaptec AIC-6915 (``Starfire'')
#devicesis# Silicon Integrated Systems SiS 900/SiS 7016
#devicesk# SysKonnect SK-984x and SK-982x gigabit ethernet
#deviceste# Sundance ST201 (D-Link DFE-550TX)
#deviceti# Alteon Networks Tigon I/II gigabit ethernet
#devicetl# Texas Instruments ThunderLAN
#devicetx# SMC EtherPower II (83c170 ``EPIC'')
#devicevr# VIA Rhine, Rhine II
#devicewb# Winbond W89C840F
#devicexl# 3Com 3c90x (``Boomerang'', ``Cyclone'')

# ISA Ethernet NICs. pccard nics included.
#devicecs# Crystal Semiconductor CS89x0 NIC
# 'device ed' requires 'device miibus'
#deviceed# NE[12]000, SMC Ultra, 3c503, DS8390 cards
#deviceex# Intel EtherExpress Pro/10 and Pro/10+
#deviceep# Etherlink III based cards
#devicefe# Fujitsu MB8696x based cards
#deviceie# EtherExpress 8/16, 3C507, StarLAN 10 etc.
#devicelnc# NE2100, NE32-VL Lance Ethernet cards
#devicesn# SMC's 9000 series of ethernet chips
#devicexe# Xircom pccard ethernet

# ISA devices that use the old ISA shims
#devicele

# Wireless NIC cards
#devicewlan# 802.11 support
#devicean# Aironet 4500/4800 802.11 wireless NICs.
#deviceawi# BayStack 660 and others
#devicewi# WaveLAN/Intersil/Symbol 802.11 wireless NICs.
#devicewl# Older non 802.11 Wavelan wireless NIC.

# Pseudo devices - the number indicates how many units to allocate.
devicerandom# Entropy device
deviceloop# Network loopback
deviceether# Ethernet support
devicesl# Kernel SLIP
deviceppp# Kernel PPP
devicetun# Packet tunnel.
devicepty# Pseudo-ttys (telnet etc)
#devicemd# Memory "disks"
#devicegif# IPv6 and IPv4 tunneling
#devicefaith# IPv6-to-IPv4 relaying (translation)

# The `bpf' device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
devicebpf# Berkeley packet filter

# USB support
deviceuhci# UHCI PCI->USB interface
deviceohci# OHCI PCI->USB interface
deviceusb# USB Bus (required)
#deviceudbp# USB Double Bulk Pipe devices
deviceugen# Generic
deviceuhid# "Human Interface Devices"
deviceukbd# Keyboard
#deviceulpt# Printer
deviceumass# Disks/Mass storage - Requires scbus and da
deviceums# Mouse
deviceurio# Diamond Rio 500 MP3 player
#deviceuscanner# Scanners
# USB Ethernet, requires mii
deviceaue# ADMtek USB ethernet
deviceaxe# ASIX Electronics USB ethernet
devicecue# CATC USB ethernet
devicekue# Kawasaki LSI USB ethernet

# FireWire support
#devicefirewire# FireWire bus code
#devicesbp# SCSI over FireWire (Requires scbus and da)
#devicefwe# Ethernet over FireWire (non-standard!)
#
##############################################################################################

配置完成后，按ESC键，然后提示按"a"后再按"a"就能够把配置文件保存。

三、编译内核：

内核文件配置好以后就能够进行内核的编译了，一般有两种编译的方式，我们采取传统的编译方式。

我们进入 /usr/src/sys/i386/conf 目录：

# cd /usr/src/sys/i386/conf

运行config命令来产生内核源代码。

# /usr/sbin/config GENERIC

切换到建立内核的目录。

# cd ../compile/GENERIC

编译内核

# make depend
# make

安装新内核。

# make install

OK,到这里，如果中间没有出现任何错误的话，那么我们的内核心就已经安装成功了，reboot后就能够使用我们的新编译的内核了。如果出现了

错误，那么请检查你的步骤是否跟上面的步骤一致，同时要检查你的内核配置文件配置的是否正确，一般编译不成功都是内核文件配置的问题

，请仔细检查。

四、新内核无法启动：

如果你编译的内核无法启动，那么可以使用以前的内核来启动。一般编译一次内核后，都会把把旧内核备份，一般/boot/kernel.old就是旧内

核的备份，出现问题就能够使用久内核来启动。

具体实现方法是：
你可以在系统启动进行10计数的时候按Enter以外的任何键， 接着键入unload命令，再键入boot kernel.old，或者任何能正常启动的内核名字

，然后就能够正常启动系统，进入系统后再重新进行内核的配置工作。

注意： 你不能仅依靠kernel.old，因为当你安装一个新内核时， kernel.old会被上一次安装的内核所覆盖，所以你要么自己手动备份一个能

正常启动的内核，或者注意你的kernel.old是否能正常启动的内核。

结束

好，到这里，我们的编译内核的工作就完成了，来然我们来看看我们的内核是否已经减小了：

# ls -l /boot/kernel/kernel
-r-xr-xr-x 1 root wheel 3090929 Sep 1 21:30 /boot/kernel/kernel

呵呵，明显把原来的5940286变成了现在的3090929，虽然没有变小一倍，但是也变小好多啦，以后系统又更快啦！

注意： 本文是在FreeBSD5.2.1的环境下进行的，不一定适合其他版本，特别是FreeBSD4.X版本，如果出现问题，请参考手册。

附：
FreeBSD中文手册: http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/books/handbook/index.html
内核配置参考: http://www.freebsd.org.cn/snap/doc/zh_CN.GB2312/bos/handbook/kernelconfig.html

WriteTime: 2004-9-2 13:20