制作initramfs镜像_乌班图initramfs问题

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主机操作系统：Centos 6.7
交叉编译器环境：arm-linux-gcc-4.5.4
开发板平台： FL2440
Linux内核版本： linux-3.0
制作文件系统类型：INITRAMFS
邮箱：leiyuxing205@gmail.com
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1. initramfs

initramfs在编译内核的同时被编译并与内核生成一个映像文件，可以压缩也可以不压缩，但是目前只支持cpio包格式。它是根文件系统制作和制作的一种非常简单的方法，也可以通过执行这个文件系统中的程序引导真正的文件系统，这样加载根文件系统的工作就不是内核的工作，而是initramfs的工作。由于initramfs使用cpio包格式，所以很容易将一个单一的文件、目录、node编译链接到系统中去，这样很简单的系统中使用起来很方便，不需要另外挂接文件系统。
但是因为cpio包实际是文件、目录、节点的描述语言包，为了描述一个文件、目录、节点，要增加很多额外的描述文字开销，特别是对于目录和节点，本身很小额外添加的描述文字却很多，这样使得cpio包比相应的image文件大很多

2.对根文件系统进行修改

由于制作initramfs文件系统启动时会在根文件系统中执行第一个init程序，它对uboot传过来的参数init=/linuxrc不予理睬，所以需要在上面制作的根文件系统里的根目录加入init程序，否则无法启动。init程序和linuxrc程序一样都是符号链接文件，它们都是指向/bin/busybox程序。

[leiyuxing@centos6 rootfs]$ ln -s bin/busybox init

[leiyuxing@centos6 rootfs]$ ll

总用量 60

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 apps

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  22 11:14 bin

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 data

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 11:58 dev

drwxrwxr-x. 4 leiyuxing leiyuxing 4096 7月  21 16:55 etc

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 info

lrwxrwxrwx. 1 leiyuxing leiyuxing   11 7月  22 11:15 init -> bin/busybox

drwxrwxr-x. 3 leiyuxing leiyuxing 4096 7月  21 11:05 lib

lrwxrwxrwx. 1 root      root        11 7月  22 11:14 linuxrc -> bin/busybox

drwxrwxr-x. 6 leiyuxing leiyuxing 4096 7月  21 10:19 mnt

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 proc

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 root

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  22 11:14 sbin

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 sys

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 10:19 tmp

drwxrwxr-x. 6 leiyuxing leiyuxing 4096 7月  21 10:19 usr

drwxrwxr-x. 2 leiyuxing leiyuxing 4096 7月  21 12:00 var

3. 添加内核对initramfs的支持

[leiyuxing@centos6 kernel]$ ls

linux-3.0  linux-3.0.tar.bz2

[leiyuxing@centos6 kernel]$ cd linux-3.0


[leiyuxing@centos6 linux-3.0]$ export TERM=vt100

[leiyuxing@centos6 linux-3.0]$ make menuconfig

。 。 。 。 。 。

General setup  --->
[*] Initial RAM filesystem and RAM disk (initramfs/initrd) support
(/home/leiyuxing/fl2440/rootfs/rootfs) Initramfs source file(s)   #输入根文件系统的所在目录 

。 。 。 。 。 。
 

[leiyuxing@centos6 linux-3.0]$ ls


arch           fs       linuxrom-s3c2440.bin  README          usr

block          include  MAINTAINERS           REPORTING-BUGS  virt

COPYING        init     Makefile              samples         vmlinux

CREDITS        ipc      mm                    scripts         vmlinux.o

crypto         Kbuild   modules.builtin       security

Documentation  Kconfig  modules.order         sound

drivers        kernel   Module.symvers        System.map

firmware       lib      net                   tools

[leiyuxing@centos6 linux-3.0]$ du -h  linuxrom-s3c2440.bin

6.8M    linuxrom-s3c2440.bin

4.制作映像文件

因为文件系统和内核是集成在一起的，所以不需要制作文件系统映像

5.添加uboot对initramfs支持

Uboot源码基本上不做修改。

下面对uboot进行修改。

[fl2440@lingyun]# set bkr 'tftp 30008000 linuxrom-s3c2440.bin;nand erase 100000 8000000;nand write 30008000 100000 800000'

[fl2440@lingyun]# set bootcmd_initramdisk 'nand read 30008000 100000 800000;bootm 30008000'

[fl2440@lingyun]# set bootargs 'console=ttyS0,115200 mem=64M init=/linuxrc rw loglevel=7'

[fl2440@lingyun]# set bootcmd 'run bootcmd_initramdisk'

[fl2440@lingyun]# save

Saving Environment to NAND...

Erasing Nand...

Erasing at 0x60000 -- 100% complete.

Writing to Nand... done

[fl2440@lingyun]# run bkr

dm9000 i/o: 0x20000300, id: 0x90000a46

DM9000: running in 16 bit mode

MAC: 08:00:3e:26:0a:51

could not establish link

operating at 100M full duplex mode

Using dm9000 device

TFTP from server 192.168.1.2; our IP address is 192.168.1.168

Filename 'linuxrom-s3c2440.bin'.

Load address: 0x30008000

Loading: T #################################################################

         #################################################################

         #################################################################

         #################################################################

         #################################################################

         #################################################################

         #################################################################

         ###############################

done

Bytes transferred = 7121280 (6ca980 hex)



NAND erase: device 0 offset 0x100000, size 0x8000000

Skipping bad block at  0x005c0000                                          

Skipping bad block at  0x031a0000                                          

Erasing at 0x80e0000 -- 100% complete.

OK



NAND write: device 0 offset 0x100000, size 0x800000

Skip bad block 0x005c0000

 8388608 bytes written: OK

6. 启动引导

[fl2440@lingyun]# boot

NAND read: device 0 offset 0x100000, size 0x800000

Skipping bad block 0x005c0000

 8388608 bytes read: OK

## Booting kernel from Legacy Image at 30008000 ...

   Image Name:   Linux Kernel

   Created:      2016-07-22   4:38:45 UTC

   Image Type:   ARM Linux Kernel Image (uncompressed)

   Data Size:    7121216 Bytes = 6.8 MiB

   Load Address: 30008040

   Entry Point:  30008040

   Verifying Checksum ... OK

   Loading Kernel Image ... OK

OK



Starting kernel ...



Uncompressing Linux... done, booting the kernel.

Linux version 3.0.0 (leiyuxing@centos6.7.localdomain) (gcc version 4.5.4 (Buildroot 2012.08) ) #5 Fri Jul 22 12:38:30 CST 2016

CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177

CPU: VIVT data cache, VIVT instruction cache

Machine: SMDK2440

Memory policy: ECC disabled, Data cache writeback

CPU S3C2440A (id 0x32440001)

S3C24XX Clocks, Copyright 2004 Simtec Electronics

S3C244X: core 405.000 MHz, memory 101.250 MHz, peripheral 50.625 MHz

CLOCK: Slow mode (1.500 MHz), fast, MPLL on, UPLL on

Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 16256

Kernel command line: console=ttyS0,115200 mem=64M init=/linuxrc rw loglevel=7

PID hash table entries: 256 (order: -2, 1024 bytes)

Dentry cache hash table entries: 8192 (order: 3, 32768 bytes)

Inode-cache hash table entries: 4096 (order: 2, 16384 bytes)

Memory: 64MB = 64MB total

Memory: 45936k/45936k available, 19600k reserved, 0K highmem

Virtual kernel memory layout:

    vector  : 0xffff0000 - 0xffff1000   (   4 kB)

    fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)

    DMA     : 0xffc00000 - 0xffe00000   (   2 MB)

    vmalloc : 0xc4800000 - 0xf6000000   ( 792 MB)

    lowmem  : 0xc0000000 - 0xc4000000   (  64 MB)

    modules : 0xbf000000 - 0xc0000000   (  16 MB)

      .init : 0xc0008000 - 0xc0e12000   (14376 kB)

      .text : 0xc0e12000 - 0xc122c000   (4200 kB)

      .data : 0xc122c000 - 0xc124fd60   ( 144 kB)

       .bss : 0xc124fd84 - 0xc1287a90   ( 224 kB)

SLUB: Genslabs=13, HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1

NR_IRQS:85

irq: clearing pending ext status 00080800

irq: clearing pending ext status 00080000

irq: clearing subpending status 00000003

irq: clearing subpending status 00000002

Console: colour dummy device 80x30

console [ttyS0] enabled

Calibrating delay loop... 201.52 BogoMIPS (lpj=503808)

pid_max: default: 32768 minimum: 301

Mount-cache hash table entries: 512

CPU: Testing write buffer coherency: ok

gpiochip_add: gpios 288..303 (GPIOK) failed to register

gpiochip_add: gpios 320..334 (GPIOL) failed to register

gpiochip_add: gpios 352..353 (GPIOM) failed to register

NET: Registered protocol family 16

S3C Power Management, Copyright 2004 Simtec Electronics

S3C2440: Initialising architecture

S3C2440: IRQ Support

S3C244X: Clock Support, DVS off

bio: create slab <bio-0> at 0

SCSI subsystem initialized

usbcore: registered new interface driver usbfs

usbcore: registered new interface driver hub

usbcore: registered new device driver usb

s3c-i2c s3c2440-i2c: slave address 0x10

s3c-i2c s3c2440-i2c: bus frequency set to 98 KHz

s3c-i2c s3c2440-i2c: i2c-0: S3C I2C adapter

Advanced Linux Sound Architecture Driver Version 1.0.24.

cfg80211: Calling CRDA to update world regulatory domain

NET: Registered protocol family 2

IP route cache hash table entries: 1024 (order: 0, 4096 bytes)

TCP established hash table entries: 2048 (order: 2, 16384 bytes)

TCP bind hash table entries: 2048 (order: 1, 8192 bytes)

TCP: Hash tables configured (established 2048 bind 2048)

TCP reno registered

UDP hash table entries: 256 (order: 0, 4096 bytes)

UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)

NET: Registered protocol family 1

RPC: Registered named UNIX socket transport module.

RPC: Registered udp transport module.

RPC: Registered tcp transport module.

RPC: Registered tcp NFSv4.1 backchannel transport module.

NetWinder Floating Point Emulator V0.97 (extended precision)

NTFS driver 2.1.30 [Flags: R/W].

JFFS2 version 2.2. (NAND) 漏 2001-2006 Red Hat, Inc.

ROMFS MTD (C) 2007 Red Hat, Inc.

msgmni has been set to 89

io scheduler noop registered

io scheduler deadline registered

io scheduler cfq registered (default)

Console: switching to colour frame buffer device 60x53

fb0: s3c2410fb frame buffer device

s3c2440-uart.0: ttyS0 at MMIO 0x50000000 (irq = 70) is a S3C2440

s3c2440-uart.1: ttyS1 at MMIO 0x50004000 (irq = 73) is a S3C2440

s3c2440-uart.2: ttyS2 at MMIO 0x50008000 (irq = 76) is a S3C2440

brd: module loaded

loop: module loaded

S3C24XX NAND Driver, (c) 2004 Simtec Electronics

s3c24xx-nand s3c2440-nand: Tacls=3, 29ns Twrph0=7 69ns, Twrph1=3 29ns

s3c24xx-nand s3c2440-nand: NAND soft ECC

NAND device: Manufacturer ID: 0xec, Chip ID: 0xda (Samsung NAND 256MiB 3,3V 8-bit)

Scanning device for bad blocks

Bad eraseblock 46 at 0x0000005c0000

Bad eraseblock 397 at 0x0000031a0000

Creating 6 MTD partitions on "NAND":

0x000000000000-0x000000100000 : "mtdblock0 u-boot 1MB"

0x000000100000-0x000001000000 : "mtdblock1 kernel 15MB"

0x000001000000-0x000005000000 : "mtdblock2 rootfs 64MB"

0x000005000000-0x00000a000000 : "mtdblock3 apps 80MB"

0x00000a000000-0x00000d000000 : "mtdblock4 data 48MB"

0x00000d000000-0x000010000000 : "mtdblock5 backup 48MB"

dm9000 Ethernet Driver, V1.31

ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver

s3c2410-ohci s3c2410-ohci: S3C24XX OHCI

s3c2410-ohci s3c2410-ohci: new USB bus registered, assigned bus number 1

s3c2410-ohci s3c2410-ohci: irq 42, io mem 0x49000000

hub 1-0:1.0: USB hub found

hub 1-0:1.0: 2 ports detected

usbcore: registered new interface driver libusual

s3c2410_udc: debugfs dir creation failed -19

mousedev: PS/2 mouse device common for all mice

S3C24XX RTC, (c) 2004,2006 Simtec Electronics

i2c /dev entries driver

sdhci: Secure Digital Host Controller Interface driver

sdhci: Copyright(c) Pierre Ossman

usbcore: registered new interface driver usbhid

usbhid: USB HID core driver

ALSA device list:

  No soundcards found.

TCP cubic registered

NET: Registered protocol family 17

lib80211: common routines for IEEE802.11 drivers

Registering the dns_resolver key type

drivers/rtc/hctosys.c: unable to open rtc device (rtc0)

Freeing init memory: 14376K

usb 1-1: new full speed USB device number 2 using s3c2410-ohci

usb 1-1: device descriptor read/64, error -62

usb 1-1: device descriptor read/64, error -62

usb 1-1: new full speed USB device number 3 using s3c2410-ohci

usb 1-1: device descriptor read/64, error -62

usb 1-1: device descriptor read/64, error -62

usb 1-1: new full speed USB device number 4 using s3c2410-ohci

usb 1-1: device not accepting address 4, error -62

usb 1-1: new full speed USB device number 5 using s3c2410-ohci

usb 1-1: device not accepting address 5, error -62

hub 1-0:1.0: unable to enumerate USB device on port 1



Copyright (C) 2016 Reagan

root login: root

Password:

>: ls

apps     data     etc      init     linuxrc  proc     sbin     tmp      var

bin      dev      info     lib      mnt      root     sys      usr

这样initramfs文件系统就自作成功

制作过程中遇到的问题

问题一：

根文件系统里没有init 和linuxrc

解决方法：

[lingyun@localhost rootfs]$ ln -s bin/busybox init

[lingyun@localhost rootfs]$ ll

total 60

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 apps

drwxr-xr-x 2 lingyun trainning 4096 Apr 26 15:16 bin

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 data

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:51 dev

drwxr-xr-x 4 lingyun trainning 4096 Apr 26 14:16 etc

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 info

lrwxrwxrwx 1 lingyun trainning   11 Apr 27 21:19 init -> bin/busybox

drwxr-xr-x 3 lingyun trainning 4096 Apr 25 21:17 lib

lrwxrwxrwx 1 root    root        11 Apr 26 15:16 linuxrc -> bin/busybox

drwxr-xr-x 6 lingyun trainning 4096 Apr 25 20:15 mnt

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 proc

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 root

drwxr-xr-x 2 lingyun trainning 4096 Apr 26 15:16 sbin

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 sys

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:15 tmp

drwxr-xr-x 6 lingyun trainning 4096 Apr 25 20:15 usr

drwxr-xr-x 2 lingyun trainning 4096 Apr 25 20:57 var

制作initramfs镜像_乌班图initramfs问题