构建linux之最小系统.docx

1、构建linux之最小系统构建linux之最小系统声明：该文件是对我2009年最后两周学习过程的总结，希望能帮助到学习中的人们。该文档按照当前日期的最新版GPL协议发布。欢迎转载，但须注明作者及出处。作者：Jim Zheng。接触Linux 4年，但是一直处于自学状态，没有机会参与Linux平台的产品开发。很希望能用上Linux平台作实际开发。联系方式:zhengweishang日期：2010.1.1内容提要：1。最小系统的意义2。最小系统的要素3。主机环境介绍4。软件版本选择5。构建完成之文件6。最小系统启动信息7。详细构建过程8。下一步工作1。最小系统的意义在我的开发经历中，每当要使用新的硬

2、件或软件平台时，我都会从他们的最小系统开始。比如新使用一款单片机，我会首先研究其电源、复位、时钟、JTAG、UART。根据这些可以搭建一个开发的最小硬件系统。我在维护一套3W行的C语言软件时，也曾将起其精简到1千行的最小系统，仅包含消息机制、在屏幕上显示一个小图标、队列服务等，而其他的功能都是一些添加上去的模块。吃透这个最小系统后，增加功能或修正bug就简单很多。最小系统有些像建房子打的地基，对它理解透了，会发现那些眼花缭乱的功能通过添砖加瓦的工作就可以完成了。现今的软硬件系统设计时模块化都做得很好，增减一个功能模块已经是个比较简单的事情。我想比较深入的学习Linux，于是想到：Linux的最

3、小系统是什么样?2。最小系统的要素Linux的发布版本都提供了大量完善的功能和服务，而我想建立的最小系统之仅包含以下要素：A. 有字符显示。B。能通过键盘输入字符C。能执行ls等简单命令根据以上需求，并分析Linux平台的架构。该最小系统特征如下A。kernel+rootfs, 不使用initrd.B. ls等命令放在rootfs中，elf格式。静态编译，不支持动态链接库。C。 kernel支持elf可执行文件格式D。 kernel不支持可加载模块功能。必要的驱动直接编译到kernel中。E。kernel应包含字符的显示驱动、键盘驱动。F。rootfs放在IDE硬盘上，所以kernel应包含P

4、ATA驱动G。rootfs为EXT3文件系统，kernel应包含EXT2、EXT3文件系统驱动。3。主机环境介绍rootgoldway # cat /proc/versionLinux version 2.6.18-1.2798.fc6 (brewbuilderhs20-bc2-) (gcc version 4.1.1 20061011 (Red Hat 4.1.1-30) #1 SMP Mon Oct 16 14:37:32 EDT 2006rootgoldway # cat /proc/cpuinfoprocessor : 0vendor_id : GenuineIntelcpu fami

5、ly : 15model : 2model name : Intel(R) Celeron(R) CPU 2.60GHzstepping : 9cpu MHz : 2625.987cache size : 128 KBfdiv_bug : nohlt_bug : nof00f_bug : nocoma_bug : nofpu : yesfpu_exception : yescpuid level : 2wp : yesflags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts a

6、cpi mmx fxsr sse sse2 ss ht tm pbe up cid xtprbogomips : 5257.90rootgoldway # lspci00:00.0 Host bridge: VIA Technologies, Inc. P4M266 Host Bridge00:01.0 PCI bridge: VIA Technologies, Inc. VT8633 Apollo Pro266 AGP00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80

7、)00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80)00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80)00:10.3 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 82)00:11.0 ISA bridge: VIA Technologies, Inc. VT8235 ISA Brid

8、ge00:11.1 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)00:11.5 * audio controller: VIA Technologies, Inc. VT8233/A/8235/8237 AC97 Audio Controller (rev 50)00:12.0 Ethernet controller: VIA Technologies, Inc. VT6102 Rhine-II (rev 74)01:00.0 VGA

9、compatible controller: nVidia Corporation NV34 GeForce FX 5200 (rev a1)rootgoldway # fdisk -lDisk /dev/hda: 160.0 GB, 160041885696 bytes255 heads, 63 sectors/track, 19457 cylindersUnits = cylinders of 16065 * 512 = 8225280 bytes Device Boot Start End Blocks IdSystem/dev/hda1 * 1 1001 8040501 7HPFS/N

10、TFS/dev/hda2 1002 19457 148247820 fW95 Extd (LBA)/dev/hda5 1002 5001 32129968+ 7HPFS/NTFS/dev/hda6 5002 9001 32129968+ 7HPFS/NTFS/dev/hda7 9002 13001 32129968+ cW95 FAT32 (LBA)/dev/hda8 13002 17001 32129968+ cW95 FAT32 (LBA)/dev/hda9 18213 19457 10000431 83Linux/dev/hda10 17002 18081 8675068+83Linux

11、/dev/hda11 18082 18212 1052226 82Linux swap / SolarisPartition table entries are not in disk orderrootgoldway # mount/dev/hda10 on / type ext3 (rw)proc on /proc type proc (rw)sysfs on /sys type sysfs (rw)devpts on /dev/pts type devpts (rw,gid=5,mode=620)tmpfs on /dev/shm type tmpfs (rw)/dev/hda7 on

12、/mnt/windows/f type vfat (rw)/dev/hda8 on /mnt/windows/g type vfat (rw)none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)sunrpc on /var/lib/nfs/rpc_pipefs type rpc_pipefs (rw)/dev/hda9 on /mnt/cdrom type ext3 (rw)请注意以下几点：A。硬盘是IDE接口，所以这篇文档描述的操作不适合于使用SATA硬盘的朋友。B。我使用的linux dist是fedora core 6. gcc v

13、ersion 4.1.1C。/dev/hda10是fc6的/, 即将构建的最小系统的文件将放在/dev/hda9中。4。软件版本选择A. 选择busybox-1.15.3构建rootfs.B. 内核版本选择linux-2.6.26.5 。gcc4.1.1不支持最新版的kernel. 5。构建完成之文件rootgoldway # ll /mnt/cdrom总计 728drwxr-xr-x 2 root root 4096 12-31 19:20 bin-rw-r-r- 1 root root 701872 01-01 00:28 bzImagedrwxr-xr-x 2 root root 409

14、6 12-31 19:27 dev-rw-r-r- 1 root root 3900 2010-01-01 dmesg.txtdrwxr-xr-x 3 root root 4096 01-01 13:03 etcdrwxr-xr-x 2 root root 4096 01-01 13:07 mntdrwxr-xr-x 2 root root 4096 12-31 19:25 procdrwxr-xr-x 2 root root 4096 12-31 19:20 sbindrwxr-xr-x 2 root root 4096 12-31 19:25 sysdrwxr-xr-x 4 root ro

15、ot 4096 12-31 19:20 usr以上文件夹打包给大家rootgoldway cdrom# tar jcf ./rootfs.tar.bz2 *rootgoldway cdrom# ll .总计 1508drwxr-xr-x 10 root root 4096 2010-01-01 cdrom-rw-r-r-1 root root 1516709 01-01 13:14 rootfs.tar.bz2drwxr-xr-x2 root root 4096 12-11 19:14 usbdrwxr-xr-x6 root root 4096 11-07 17:38 windows以下为gr

16、ub引导设置：rootgoldway # cat /etc/grub.conf# grub.conf generated by anaconda# Note that you do not have to rerun grub after making changes to this file# NOTICE:You do not have a /boot partition.This means that# all kernel and initrd paths are relative to /, eg.# root (hd0,9)# kernel /boot/vmlinuz-versio

17、n ro root=/dev/hda10# initrd /boot/initrd-version.img#boot=/dev/hdadefault=2timeout=5splashimage=(hd0,9)/boot/grub/splash.xpm.gzhiddenmenutitle kernel test root (hd0,8) kernel /bzImage ro root=/dev/hda9title Fedora Core (2.6.18-1.2798.fc6) root (hd0,9) kernel /boot/vmlinuz-2.6.18-1.2798.fc6 ro root=

18、LABEL=/1 rhgb quiet initrd /boot/initrd-2.6.18-1.2798.fc6.imgtitle Other rootnoverify (hd0,0) chainloader +16。最小系统启动信息Linux version 2.6.26.5 (rootgoldway) (gcc version 4.1.1 20061011 (Red Hat 4.1.1-30) #12 Fri Jan 1 00:28:28 CST 2010BIOS-provided physical RAM map:BIOS-e820: 0000000000000000 - 000000

19、000009fc00 (usable)BIOS-e820: 000000000009fc00 - 00000000000a0000 (reserved)BIOS-e820: 00000000000f0000 - 0000000000100000 (reserved)BIOS-e820: 0000000000100000 - 000000000fff0000 (usable)BIOS-e820: 000000000fff0000 - 000000000fff3000 (ACPI NVS)BIOS-e820: 000000000fff3000 - 0000000010000000 (ACPI da

20、ta)BIOS-e820: 00000000fec00000 - 0000000100000000 (reserved)0MB HIGHMEM available.255MB LOWMEM available.Entering add_active_range(0, 0, 65520) 0 entries of 256 usedZone PFN ranges:DMA 0 - 4096Normal 4096 - 65520HighMem 65520 - 65520Movable zone start PFN for each nodeearly_node_map1 active PFN rang

21、es 0: 0 - 65520On node 0 totalpages: 65520DMA zone: 32 pages used for memmapDMA zone: 0 pages reservedDMA zone: 4064 pages, LIFO batch:0Normal zone: 480 pages used for memmapNormal zone: 60944 pages, LIFO batch:15HighMem zone: 0 pages used for memmapMovable zone: 0 pages used for memmapDMI 2.3 prese

22、nt.Allocating PCI resources starting at 20000000 (gap: 10000000:eec00000)Built 1 zonelists in Zone order, mobility grouping on.Total pages: 65008Kernel command line: ro root=/dev/hda9Enabling fast FPU save and restore. done.Enabling unmasked SIMD FPU exception support. done.Initializing CPU#0PID has

23、h table entries: 1024 (order: 10, 4096 bytes)Detected 2625.912 MHz processor.Console: colour VGA+ 80x25console tty0 enabledDentry cache hash table entries: 32768 (order: 5, 131072 bytes)Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)Memory: 257764k/262080k available (912k kernel code,

24、3808k reserved, 300k data, 100k init, 0k highmem)virtual kernel memory layout: fixmap: 0xfffee000 - 0xfffff000 (68 kB) pkmap : 0xff800000 - 0xffc00000 (4096 kB) vmalloc : 0xd0800000 - 0xff7fe000 ( 751 MB) lowmem: 0xc0000000 - 0xcfff0000 ( 255 MB) .init : 0xc0232000 - 0xc024b000 ( 100 kB) .data : 0xc

25、01e4097 - 0xc022f42c ( 300 kB) .text : 0xc0100000 - 0xc01e4097 ( 912 kB)Checking if this processor honours the WP bit even in supervisor mode.Ok.CPA: page pool initialized 1 of 1 pages preallocatedSLUB: Genslabs=12, HWalign=128, Order=0-3, MinObjects=0, CPUs=1, Nodes=1Calibrating delay using timer s

26、pecific routine. 5257.16 BogoMIPS (lpj=10514322)Mount-cache hash table entries: 512CPU: Trace cache: 12K uops, L1 D cache: 8KCPU: L2 cache: 128KCPU: Intel(R) Celeron(R) CPU 2.60GHz stepping 09Checking hlt instruction. OK.Freeing SMP alternatives: 0k freedSetting up standard PCI resourcesio scheduler

27、 noop registered (default)Uniform Multi-Platform E-IDE driveride: Assuming 50MHz system bus speed for PIO modes; override with idebus=xxide_generic: please use probe_mask=0x3f module parameter for probing all legacy ISA IDE portsProbing IDE interface ide0.hda: ST3160215A, ATA DISK driveProbing IDE i

28、nterface ide1.ide0 at 0x1f0-0x1f7,0x3f6 on irq 14ide1 at 0x170-0x177,0x376 on irq 15hda: max request size: 512KiBhda: 312581808 sectors (160041 MB) w/2048KiB Cache, CHS=19457/255/63hda: cache flushes supportedhda: hda1 hda2 serio: i8042 KBD port at 0x60,0x64 irq 1serio: i8042 AUX port at 0x60,0x64 i

29、rq 12mice: PS/2 mouse device common for all miceUsing IPI Shortcut modeinput: AT Translated Set 2 keyboard as /devices/platform/i8042/serio0/input/input0kjournald starting.Commit interval 5 secondsEXT3-fs: mounted filesystem with ordered data mode.VFS: Mounted root (ext3 filesystem) readonly.Freeing unused kernel memory: 100k freedEXT3-fs warning: maximal mount count reached, running e