create an initramfs on mdm9x40

利用linux提供的script建立initramfs在先前的文章已經提過，可參考如何利用kvm/qemu練習linux module之new update，基本上就是呼叫gen_initramfs_list.sh建立file system清單，使用gen_init_cpio將清單轉成CPIO格式後，在使用gzip做壓縮。相關指令如下：

W=/home/brook/projects/9x40/apps_proc
RD=/home/brook/projects/initramfs
CPIO=/home/brook/projects/initramfs.cpio
SYSROOT=${W}/oe-core/build/tmp-eglibc/sysroots/
OUTPUT=/home/brook/projects/9x40-initramfs.img
sh ${W}/kernel/scripts/gen_initramfs_list.sh -d ${RD} > /tmp/gen_initramfs_list
${W}/oe-core/build/tmp-eglibc/sysroots/mdm9640/usr/src/kernel/usr/gen_init_cpio /tmp/gen_initramfs_list > ${CPIO}
gzip -c ${CPIO} > ${CPIO}.gz

我是copy recipes/linux-quic/linux-quic_git.bb裡面的do_deploy()，接著修改成另外一個script，來建立image，指令如下：

${SYSROOT}/x86_64-linux/usr/bin/mkbootimg --kernel ${SYSROOT}/mdm9640/boot/zImage-3.10.49 --dt ${SYSROOT}/mdm9640/boot/masterDTB --ramdisk ${CPIO}.gz --cmdline "dynamic_debug.verbose=1 root=/dev/ram rootfstype=ramfs console=ttyHSL0,115200,n8 androidboot.hardware=qcom ehci-hcd.park=3 msm_rtb.filter=0x37" --base 0x81C00000 --tags-addr 0x81900000 --pagesize 2048 --ramdisk_offset 0xd32000 --output ${OUTPUT}

這裡的重點是cmdline要改成"root=/dev/ram rootfstype=ramfs"，否則在lk的lk/app/aboot/aboot.c:update_cmdline()會塞一些information給kernel，導致無法由initramfs開機。

相關檔案位置： https://www.codeaurora.org/cgit/quic/le/mdm/manifest/tree/?id=LNX.LE.5.0.1-57014-9x40
LNX.LE.5.0.1-57014-9x40.xml: repo manifest file,

https://www.codeaurora.org/cgit/quic/le/kernel/lk/tree/app/aboot/aboot.c?id=LNX.LE.5.0.1-57014-9x40
lk/app/aboot/aboot.c: unsigned char *update_cmdline(const char * cmdline)

https://www.codeaurora.org/cgit/quic/le/oe/recipes/tree/conf/machine/mdm9640.conf?h=LNX.LE.5.0.1_rb1.7
conf/machine/mdm9640.conf: MACHINE_KERNEL_TAGS_OFFSET = "0x81900000"

https://www.codeaurora.org/cgit/quic/le/oe/recipes/tree/recipes/linux-quic/linux-quic_git.bb?id=LNX.LE.5.0.1-57014-9x40
recipes/linux-quic/linux-quic_git.bb: do_deploy()

如何利用kvm/qemu練習linux module之new update

本文是如何利用kvm/qemu練習linux module的更新版。

brook@vista:~/qemu$ git clone git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux
Cloning into 'linux'...
remote: Counting objects: 4153172, done.
remote: Compressing objects: 100% (548/548), done.
remote: Total 4153172 (delta 278), reused 0 (delta 0)
Receiving objects: 100% (4153172/4153172), 919.28 MiB | 2.32 MiB/s, done.
Resolving deltas: 100% (3423945/3423945), done.
Checking out files: 100% (49457/49457), done.
brook@vista:~/qemu$ cd linux/
brook@vista:~/qemu/linux$ git tag -l | tac | head -2
v4.1-rc8
v4.1-rc7
brook@vista:~/qemu/linux$ cp /boot/config-3.8.0-35-generic .config
brook@vista:~/qemu/linux$ make ARCH=i386 olddefconfig
  HOSTCC  scripts/basic/fixdep
  HOSTCC  scripts/kconfig/conf.o
  SHIPPED scripts/kconfig/zconf.tab.c
  SHIPPED scripts/kconfig/zconf.lex.c
  SHIPPED scripts/kconfig/zconf.hash.c
  HOSTCC  scripts/kconfig/zconf.tab.o
  HOSTLD  scripts/kconfig/conf
scripts/kconfig/conf  --olddefconfig Kconfig
.config:550:warning: symbol value 'm' invalid for ACPI_PCI_SLOT
.config:553:warning: symbol value 'm' invalid for ACPI_HOTPLUG_MEMORY
.config:665:warning: symbol value 'm' invalid for HOTPLUG_PCI_ACPI
.config:4522:warning: symbol value 'm' invalid for FB_VESA
.config:5062:warning: symbol value 'm' invalid for USB_ISP1760_HCD
.config:6150:warning: symbol value 'm' invalid for VME_BUS
#
# configuration written to .config
#
brook@vista:~/qemu/linux$ make ARCH=i386 all
scripts/kconfig/conf  --silentoldconfig Kconfig
  SYSTBL  arch/x86/syscalls/../include/generated/asm/syscalls_32.h
  SYSHDR  arch/x86/syscalls/../include/generated/uapi/asm/unistd_32.h
  SYSHDR  arch/x86/syscalls/../include/generated/uapi/asm/unistd_64.h
...(略)
  IHEX    firmware/yam/1200.bin
  IHEX    firmware/yam/9600.bin
brook@vista:~/qemu/linux$ cd ..
brook@vista:~/qemu$ git clone git://busybox.net/busybox.git
Cloning into 'busybox'...
remote: Counting objects: 91770, done.
remote: Compressing objects: 100% (23149/23149), done.
remote: Total 91770 (delta 71829), reused 86760 (delta 68061)
Receiving objects: 100% (91770/91770), 21.68 MiB | 805 KiB/s, done.
Resolving deltas: 100% (71829/71829), done.
brook@vista:~/qemu$ cd busybox
brook@vista:~/qemu/busybox$ make defconfig
scripts/kconfig/conf -d Config.in
*
* Busybox Configuration
...(略)
  Use the klogctl() interface (FEATURE_KLOGD_KLOGCTL) [Y/n/?] (NEW) y
logger (LOGGER) [Y/n/?] (NEW) y
brook@vista:~/qemu/busybox$ sed -i 's/.*CONFIG_STATIC.*/CONFIG_STATIC=y/' .config
brook@vista:~/qemu/busybox$ make CFLAGS="-m32" LDFLAGS="-m32" all
scripts/kconfig/conf -s Config.in
#
# using defaults found in .config
#
...(略)
  DOC     busybox.1
  DOC     BusyBox.html
brook@vista:~/qemu/busybox$ file busybox
busybox: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked, for GNU/Linux 2.6.24, BuildID[sha1]=0x87675efbb7f7f810a462113cb2913bab73ffb1b6, stripped
brook@vista:~/qemu/busybox$ cd ..x
brook@vista:~/qemu$ ./create_initrd_by_linux_script.sh
+ INITD=initrd
+ rm -rf initrd
+ mkdir -p initrd/sbin initrd/bin initrd/sys initrd/tmp initrd/dev initrd/proc
+ mkdir -p initrd/usr/sbin initrd/usr/bin initrd/etc/init.d
+ install -m 0755 busybox/busybox initrd/bin
+ install -m 0755 init initrd/
+ ln -s ../bin/busybox initrd/sbin/mdev
+ ln -s busybox initrd/bin/sh
+ ln -s busybox initrd/bin/mkdir
+ ln -s busybox initrd/bin/mount
+ ./linux/scripts/gen_initramfs_list.sh -d initrd
+ ./linux/usr/gen_init_cpio /tmp/brook_initramfs_list
brook@vista:~/qemu$ qemu-system-i386 -kernel linux/arch/x86/boot/bzImage -initrd initrd.img

create_initrd_by_linux_script.sh

#!/bin/bash
INITD="initrd"
rm -rf ${INITD}
mkdir -p ${INITD}/sbin ${INITD}/bin ${INITD}/sys ${INITD}/tmp ${INITD}/dev ${INITD}/proc
mkdir -p ${INITD}/usr/sbin ${INITD}/usr/bin ${INITD}/etc/init.d
install -m 0755 busybox/busybox ${INITD}/bin
install -m 0755 init ${INITD}/
ln -s ../bin/busybox ${INITD}/sbin/mdev

ln -s busybox ${INITD}/bin/sh
ln -s busybox ${INITD}/bin/mkdir
ln -s busybox ${INITD}/bin/mount

./linux/scripts/gen_initramfs_list.sh -d ${INITD} > /tmp/brook_initramfs_list
./linux/usr/gen_init_cpio /tmp/brook_initramfs_list > initrd.img

apt-get update之更新non-LTS套件之解法

Ubuntu之非NON-LTS(Long Term Support)版本，通常9個月後就不再support，所以apt-get update更新往往就會看到找不到package的錯誤。 此時這些舊的package都會被移到http://old-releases.ubuntu.com/，所以要改一下路徑apt package的路徑。

brook@vista:~$ cat /etc/issue
Ubuntu 13.04 \n \l
 
brook@vista:~$ sudo apt-get update
[sudo] password for brook:
Ign http://extras.ubuntu.com raring Release.gpg
Ign http://archive.ubuntu.com raring Release.gpg
....
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/main/binary-i386/Packages  404  Not Found [IP: 91.189.88.149 80]
 
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/restricted/binary-i386/Packages  404  Not Found [IP: 91.189.88.149 80]
 
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/universe/binary-i386/Packages  404  Not Found [IP: 91.189.88.149 80]
 
W: Failed to fetch http://security.ubuntu.com/ubuntu/dists/raring-security/multiverse/binary-i386/Packages  404  Not Found [IP: 91.189.88.149 80]
 
E: Some index files failed to download. They have been ignored, or old ones used instead.

Solution：

brook@vista:~$ cat /etc/apt/sources.list
#deb http://old-releases.ubuntu.com/ raring-security main
#deb http://old-releases.ubuntu.com/ubuntu/dists/raring-security/restricted/ raring-security main
deb http://old-releases.ubuntu.com/ubuntu/ raring main
deb http://old-releases.ubuntu.com/ubuntu/ raring universe

參考資料：
1. Ubuntu LTS(Long Term Support)
2. Old Ubuntu Releases