initramfs 使用

使用initramfs可以实现内核和文件系统在一个映像文件中，不过会增大内核体积，同时占用较多内存。

（1）准备根文件系统

先准备好根文件系统，放到某个目录，不过为了方便和内核一起打包，可以放到内核源代码的usr/目录下，我的做法是在usr目录下建立了image目录，然后将可用的根文件系统的内容全部复制到image目录下：

[chenxibing@localhost linux-2.6.27.8-smartarm3250]$ ls usr/image

bin dev hello.c home lib mnt proc sbin tmp var

boot etc hello_static init Makefile opt root sys usr

另外千万注意，initramfs识别的第一个进程名称为init，因此需要将原来根文件系统中busybox的linuxrc链接改名为init。

（2）配置内核

配置内核，在General setup中使能initramfs，

[*] Initial RAM filesystem and RAM disk (initramfs/initrd) support

(./usr/image) Initramfs source file(s)

同时在Userspace binary formats 中使能elf文件支持：

[*] Kernel support for ELF binaries

（3）编译内核，加载运行

make

make uImage

编译出来后内核较大，由于根文件系统也比较大，我得到的内核有11M，加载后运行，解压的时间也变长了，但是内核运行之后很快就进入到shell界面了。

U-Boot 1.3.3 (Sep 1 2009 - 12:31:06)

DRAM: 64 MB

Flash: 2 MB

NAND: 256 MiB

In: serial

Out: serial

Err: serial

Hit any key to stop autoboot: 0

U-Boot$ ru nfsboot

HW MAC address: 00:01:90:00:C0:81

ENET:auto-negotiation complete

ENET:Link status up

ENET:FULL DUPLEX

ENET:100MBase

TFTP from server 192.168.7.238; our IP address is 192.168.7.236

Filename 'uImage'.

Load address: 0x81000000

Loading: #################################################################

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

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

done

Bytes transferred = 12108228 (b8c1c4 hex)

## Booting kernel from Legacy Image at 81000000 ...

Image Name: Linux-2.6.27.8

Image Type: ARM Linux Kernel Image (uncompressed)

Data Size: 12108164 Bytes = 11.5 MB

Load Address: 80008000

Entry Point: 80008000

Verifying Checksum ... OK

Loading Kernel Image ... OK

Starting kernel ...

Uncompressing Linux.............................................................................................................................................................................................................................................................................................................................................. done, booting the kernel.

Linux version 2.6.27.8 (chenxibing@localhost.localdomain) (gcc version 4.3.2 (crosstool-NG-1.3.1) ) #9 PREEMPT Thu Sep 3 09:55:52 CST 2009

CPU: ARM926EJ-S [41069264] revision 4 (ARMv5TEJ), cr=00053177

Machine: SmartARM3250 board with the LPC3250 Microcontroller

Memory policy: ECC disabled, Data cache writeback

CPU0: D VIVT write-back cache

CPU0: I cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets

CPU0: D cache: 32768 bytes, associativity 4, 32 byte lines, 256 sets

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

Kernel command line: root=/dev/mtdblock4 console=ttyS0,115200 mem=64M rootfstype=yaffs2

PID hash table entries: 256 (order: 8, 1024 bytes)

Console: colour dummy device 80x30

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: 50972KB available (3352K code, 238K data, 10296K init)

Calibrating delay loop... 129.84 BogoMIPS (lpj=649216)

Mount-cache hash table entries: 512

CPU: Testing write buffer coherency: ok

net_namespace: 288 bytes

NET: Registered protocol family 16

Invalid board descriptor!

LPC32XX DMA driver

SCSI subsystem initialized

usbcore: registered new interface driver usbfs

usbcore: registered new interface driver hub

usbcore: registered new device driver usb

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

NET: Registered protocol family 1

NetWinder Floating Point Emulator V0.97 (double precision)

yaffs Sep 3 2009 09:30:12 Installing.

msgmni has been set to 99

io scheduler noop registered

io scheduler anticipatory registered

io scheduler deadline registered

io scheduler cfq registered (default)

CLCD: ZHIYUAN LCD hardware, XVGA portrait display

Console: switching to colour frame buffer device 128x48

Serial: 8250/16550 driver4 ports, IRQ sharing disabled

serial8250.0: ttyS0 at MMIO 0x40090000 (irq = 9) is a 16550A

console [ttyS0] enabled

serial8250.0: ttyS1 at MMIO 0x40080000 (irq = 7) is a 16550A

serial8250.0: ttyS2 at MMIO 0x40088000 (irq = 8) is a 16550A

serial8250.0: ttyS3 at MMIO 0x40098000 (irq = 10) is a 16550A

lpc32xx_hsuart.0: ttyTX0 at MMIO 0x40014000 (irq = 26) is a lpc32xx_hsuart

lpc32xx_hsuart.0: ttyTX1 at MMIO 0x40018000 (irq = 25) is a lpc32xx_hsuart

lpc32xx_hsuart.0: ttyTX2 at MMIO 0x4001c000 (irq = 24) is a lpc32xx_hsuart

loop: module loaded

LPC32XX_mii_bus: probed

eth0: LPC32XX mac at 0x31060000 irq 29

eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=0:00, irq=-1)

Uniform Multi-Platform E-IDE driver

ide0 at 0xc4866020-0xc486602e,0xc486602e on irq 86

Driver 'sd' needs updating - please use bus_type methods

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

Scanning device for bad blocks

Bad eraseblock 627 at 0x04e60000

Creating 5 MTD partitions on "lpc32xx_nand":

0x00000000-0x00180000 : "smartarm3250-boot"

0x00180000-0x001c0000 : "smartarm3250-ubt-prms"

0x00200000-0x00600000 : "smartarm3250-kernel"

0x00600000-0x01600000 : "smartarm3250-safefs"

0x01600000-0x10000000 : "smartarm3250-rootfs"

at25 spi0.0: 32 KByte at25256a eeprom, pagesize 64

I2C device at address 0x2d<6>ISP1301 Vendor ID : 0x04cc

ISP1301 Product ID : 0x1301

ISP1301 Version ID : 0x0210

usb-ohci usb-ohci: at 0xf3120000, irq 0

usb-ohci usb-ohci: pnx4008 OHCI

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

usb-ohci usb-ohci: irq 59, io mem 0xf3120000

usb usb1: configuration #1 chosen from 1 choice

hub 1-0:1.0: USB hub found

hub 1-0:1.0: 2 ports detected

Initializing USB Mass Storage driver...

usbcore: registered new interface driver usb-storage

USB Mass Storage support registered.

mice: PS/2 mouse device common for all mice

input: LPC32xx Touchscreen as /class/input/input0

rtc-pcf8563 3-0051: chip found, driver version 0.4.3

rtc-pcf8563 3-0051: rtc core: registered rtc-pcf8563 as rtc0

rtc-lpc32xx rtc-lpc32xx: rtc core: registered rtc-lpc32xx as rtc1

i2c /dev entries driver

PNX4008-WDT: PNX4008 Watchdog Timer: heartbeat 19 sec

mmci-pl18x: DMA buffer(10000 bytes), P:0x812b0000, V:0xffdc0000

mmc0: MMCI rev 0 cfg 00 at 0x0000000020098000 irq 15,13

usbcore: registered new interface driver usbhid

usbhid: v2.6:USB HID core driver

Advanced Linux Sound Architecture Driver Version 1.0.17.

ASoC version 0.13.2

UDA1380 Audio Codec 0.6<6>ALSA device list:

No soundcards found.

TCP cubic registered

NET: Registered protocol family 17

RPC: Registered udp transport module.

RPC: Registered tcp transport module.

ieee80211: 802.11 data/management/control stack, git-1.1.13

VFP support v0.3: implementor 41 architecture 1 part 10 variant 9 rev 1

rtc-pcf8563 3-0051: setting system clock to 2009-09-03 10:09:04 UTC (1251972544)

Freeing init memory: 10296K #占用的内存很大

init started: BusyBox v1.11.2 ()

starting pid 326, tty '': '/etc/rc.d/rcS'

Mounting /proc and /sys

Setting the hostname to zlg

Mounting filesystems

Running sysctl

Setting up networking on loopback device:

Setting up networking on eth0:

Adding static route for default gateway to 192.168.7.1:

Setting nameserver to 192.168.7.1 in /etc/resolv.conf:

Starting inetd:

Starting the port mapper:

starting pid 369, tty '': '-/bin/sh'

[root@zlg /]# ls

Makefile etc init proc tmp

bin hello.c lib root usr

boot hello_static mnt sbin var

dev home opt sys

[root@zlg /]# ls

Makefile etc init proc tmp

bin hello.c lib root usr

boot hello_static mnt sbin var

dev home opt sys

[root@zlg /]# free

total used free shared buffers

Mem: 61328 44732 16596 0 0

Swap: 0 0 0

Total: 61328 44732 16596

posted on 2012-04-28 15:27 风行雪舞阅读(873) 评论(0) 编辑收藏举报

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initramfs 使用

（1）准备根文件系统

（2）配置内核

（3）编译内核，加载运行

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