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[Q] Making android kernel compatible with ubuntu?

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Hello.

I noticed that kernels for ubuntu seem a bit old. I was thinking that maybe someone could modify cm10(or 3.0.21) kernel to support ubuntu/teach me how to add ubuntu support to android kernel. I did a bit googling, but results were filled with those loop ubuntus, not native.
I am also thankful if someone can point me to right direction.

(Trevd, i am counting on you )

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9th December 2012, 11:25 AM |#2  
Quote:
Originally Posted by julle131

Hello.

I noticed that kernels for ubuntu seem a bit old. I was thinking that maybe someone could modify cm10(or 3.0.21) kernel to support ubuntu/teach me how to add ubuntu support to android kernel. I did a bit googling, but results were filled with those loop ubuntus, not native.
I am also thankful if someone can point me to right direction.

(Trevd, i am counting on you )

Sent from my GT-I9100 using xda app-developers app

Well as seeing as you ask so nicely, I'm far from an expert however especially in the ways of ubuntu kernels, A1Pha got the original ubuntu image going but ubuntu have done an official arm release now so that changes things ( probably ) I can only point you in the direction of more, hopefully better resources.

The Blaze Tablet seems to have have been the Development Platform for the G9 so you'll probably get some purchase from following that route.
Here's some links for you.

http://omappedia.org/wiki/Source_Trees
http://omappedia.org/wiki/OMAP_Ubuntu_Main

My days on the G9 could well be numbered, I foolishly overwrote the bootlloader in one of my more Laissez-faire moments. meh! That's what I get for having a caliver approach to consumer electronics.
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9th December 2012, 01:32 PM |#3  
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Quote:
Originally Posted by trevd

Well as seeing as you ask so nicely, I'm far from an expert however especially in the ways of ubuntu kernels, A1Pha got the original ubuntu image going but ubuntu have done an official arm release now so that changes things ( probably ) I can only point you in the direction of more, hopefully better resources.

The Blaze Tablet seems to have have been the Development Platform for the G9 so you'll probably get some purchase from following that route.
Here's some links for you.

http://omappedia.org/wiki/Source_Trees
http://omappedia.org/wiki/OMAP_Ubuntu_Main

My days on the G9 could well be numbered, I foolishly overwrote the bootlloader in one of my more Laissez-faire moments. meh! That's what I get for having a caliver approach to consumer electronics.

Thanks for answering. I'm out of thanks for today, so i press that button when i have more.
Now to business.
After doing some research, and asking few questions on #ubuntu-arm, this seems a bit hard project because there are no sources. There is no source for CM10 kernel(Or i can't read the github) nor Ubuntu kernel, so i can't just apply tweaks of them both to archos 3.0.8+ kernel. A way to unpack the zimage from ubuntu kernel and cm10 kernel would help, but atleast the script i tried couldn't unpack the zimage of ubuntu. Lets see what i figure out next.
10th December 2012, 05:26 PM |#4  
Quote:
Originally Posted by julle131

After doing some research, and asking few questions on #ubuntu-arm, this seems a bit hard project because there are no sources. There is no source for CM10 kernel(Or i can't read the github) nor Ubuntu kernel, so i can't just apply tweaks of them both to archos 3.0.8+ kernel. A way to unpack the zimage from ubuntu kernel and cm10 kernel would help, but atleast the script i tried couldn't unpack the zimage of ubuntu. Lets see what i figure out next.

Not sure what you mean by the CM10 Kernel, I don't think CM have any different settings from what is required by JellyBean itself. Plus the Kernel we originally used for the Archos CM10 is an ICS kernel with IPV6 Mangling adding, we got away with that because the Init.rc used to boot the Rom is a mashed up ICS Version. After thinking about it let me add the bit of knowledge I think I do know.

The kernels on arm platforms, to paraphrase Linus Tovalds was a complete mess, something which Linaro are working hard to fix, and are unique to the SOC vendor.

You need to get the Archos specific sources which are located on GItorious @ git://gitorious.org/archos/archos-gpl-gen9-kernel-ics.git, clone the 3.0.21 branch, in the directory there's a file called linux.config.g9 ( or something similar ). that's the config file. I just copy that to .config, change the settings I need to (if any) compile. That should setup an archos kernel which should run android
Code:
git clone git://gitorious.org/archos/archos-gpl-gen9-kernel-ics.git -b linux-icc-3.0.21
cp linux.config.g9 .config
make menuconfig
make -j8
Like I say I was thinking about it and the main difference between a standard kernel and android kernels is the binder, the switch class support and the log driver ( this is things I've noticed when building an android x86 Kernel )

When doing menuconfig the Android Driver settings are found in devices/staging/android, I suppose a place to start is to turn them off then switch on SYSV IPC ( i think that's in genral kernel settings ), from what I understand this is the sysv binder and should create a node at /dev/binder, standard kernel switch class support is set in Device Drivers ( Switch Class Support ).

I'm not sure about logging , It basically breaks down like this. The Android Kernel has a specific logging driver this creates device node at /dev/log/main /dev/log/system etc , Ubunutu ( on x86 at least ) has a single log device node which is created at /dev/log, I don't know weather this is something created by the kernel or something created in userspace by syslogd or something similar. I also don't know whether the Android Logs are compatible with ubuntu, or the android binder for that matter. I'll try and boot my x86 ubuntu with my Android Kernel later on , I suspect It won't work but speculation is one thing, knowing for sure is better

With regards to unpacking the zImage, I'll say this , Not all zImages are created equal , I notice you are using a samsung mobile ( galaxy s, if I'm not mistaken ) , so you're probably using the samsung zImage as a frame of reference... How I understand it Samsung pack the initramfs into the zImage, similar, but not same to the way android AOSP pack a boot.img. Samsung however do this in kernel itself, this is why Samsung zImage a) can be unpacked and b) require different tools than the standard tools used for unpacking boot images which work on just about every other device ( expect Archos of course ) . So you generally don't unpack zImage because It's just a binary blob that contains all the kernel functions, this is in the assembly language of whatever architecture you built your kernel for.

Given all that info you should now be able to build a working archos android kernel ( I assume you using linux etc and your not stupid ) , You now need the Ubuntu side of things..... Have you asked in the Archos G9 Ubuntu Development thread, they may be able to shed light on the changes to the config you need to make or alternativaly you could download the Ubuntu for Arm OMAP Image from https://wiki.ubuntu.com/ARM/OMAP , unpack/mount it and see if there is the kernel .config file, It is normally packaged somehow with the distro for example x86 lubuntu has .configs in /lib/modules/3.5.0-19-generic/build/.config, the arm distro may have something similar. Then it's a case of see what configuration options are different, You can't just copy the config whole sale however because there are Archos Specific board settings in the Archos Kernel. Failing that the kernel sources will be somewhere as it is a legal requirement under the GPL and Cannonical are compliant, at least I've not read anywhere to the contrary.

This is just really how I understand it at the minute, Some of it could be inaccurate or just plain BS but hopefully should give you something to run with, there is a bit of a barrier to entry on the whole subject kernels/android kernels as the information is in little pieces all over the internet, when I was first getting to grips with it, it did feel like a bit a of treasure hunt for knowledge. Also knowing the Keywords to search for in the first place can be difficult It sounds quite an interesting challenge, shame about my brick!!

If you want to understand more about the kernel generally ( and lets face it, who doesn't ) then Linux Kernel in a nutshell ( http://www.kroah.com/lkn/ ) is a free e-book written by one of the kernel maintainers a should be a useful reference.

JUST IN CASE: Don't forget prefixing a filename with a fullstop (.) makes that file hidden and won't display in normal file listings, using ls -a to display all file in a directory
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10th December 2012, 05:55 PM |#5  
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The CM10 kernel i was refering to is the CM10 in dev section. I thought there were other "hacks" than just a IPv6 addon, and that's why i counsidered it as a totally diferent kernel.

I think i need to download the kernel source as soons as i get to my laptop then. I have some experience on it, because i have made a few builds of B2G, but that was mainly just: download source, choose the device and build.

For the differences, that is what i consider as the hardest part. Merging them and then getting the kernel to build might take some time. Luckily I have plenty of time.

For the zImage, I was trying to unpack the ubuntu zImage one, because I'm working on archos device . Unpacking Galaxy S2 kernel wouldn't make any sense. atleast to me . I was trying to use a general unpacker, but it didn't work, just as you wrote.

For the OS & Knowledge, i am using linux indeed. Backbox, which is based on ubuntu 11.04 to be precise. I didn't even think about unpacking the IMG file... Maybe i am stupid . I think i am able to mount it to folder, so it is easy to explore.

I think I know the basics, and folders starting with . is part of them

Lets see what happens the next time i pick my laptop, boot it and start fooling around .

Edit: Well, after the menuconfig, i can't fand anything related to ipv6 mangling. There was a file on the root of cloned folder called linux.config, but it was the default config for kernel, not archos specific.
10th December 2012, 07:03 PM |#6  
Quote:
Originally Posted by julle131

The CM10 kernel i was refering to is the CM10 in dev section. I thought there were other "hacks" than just a IPv6 addon, and that's why i counsidered it as a totally diferent kernel.

I think i need to download the kernel source as soons as i get to my laptop then. I have some experience on it, because i have made a few builds of B2G, but that was mainly just: download source, choose the device and build.

For the differences, that is what i consider as the hardest part. Merging them and then getting the kernel to build might take some time. Luckily I have plenty of time.

For the zImage, I was trying to unpack the ubuntu zImage one, because I'm working on archos device . Unpacking Galaxy S2 kernel wouldn't make any sense. atleast to me . I was trying to use a general unpacker, but it didn't work, just as you wrote.

For the OS & Knowledge, i am using linux indeed. Backbox, which is based on ubuntu 11.04 to be precise. I didn't even think about unpacking the IMG file... Maybe i am stupid . I think i am able to mount it to folder, so it is easy to explore.

I think I know the basics, and folders starting with . is part of them

Lets see what happens the next time i pick my laptop, boot it and start fooling around .

The 3.0.31 Kernel started by Quallenauge in the dev section is an Highly Expirimental effort. this was started before Archos released the 3.0.21 Kernel with their 4.0.2x roms which covered what was trying to be achieved by this development, It's best left alone unless you really want to get you're hands dirty with device bring up code, There's a version on my github which I think boots the G9A101's as well as the 80's......... anyway

You shouldn't have to do any merging of code, more a case of selecting the right options in the config, Thinking back, I've have booted Ubuntu using mainline kernel sources from kernel.org that I built myself so that kinda of suggests there's nothing special about ubuntu's kernels per se' .

Your main problem won't be with building , more booting, It should compile fine but I wouldn't be surprised to be looking at a blank screen then your problem is monitoring the output....There's an option in the archos config to get early debug output over USB, I think there's some modification you need to make to the USB Cable, Quallenauge knows about that, he did it , I was ghetto and used adb for my debugging. which can be probably made to work when booting ubuntu but I'd go the correct route , I just have my wierd ways of doing things.

Another thing that spring to mind with android "specialisms". Android runs /init in the root directory ubuntu normally likes /sbin/init. This is something that is specified again in the kernel config using the kernel cmdline option , just something to be aware of... If anything else springs to mind I'll let you know.

So I suppose as you say, Just fool around and see what happens.

Quote:

I think I know the basics, and folders starting with . is part of them

Just Checking LOL.
10th December 2012, 07:47 PM |#7  
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Quote:
Originally Posted by trevd

The 3.0.31 Kernel started by Quallenauge in the dev section is an Highly Expirimental effort. this was started before Archos released the 3.0.21 Kernel with their 4.0.2x roms which covered what was trying to be achieved by this development, It's best left alone unless you really want to get you're hands dirty with device bring up code, There's a version on my github which I think boots the G9A101's as well as the 80's......... anyway

You shouldn't have to do any merging of code, more a case of selecting the right options in the config, Thinking back, I've have booted Ubuntu using mainline kernel sources from kernel.org that I built myself so that kinda of suggests there's nothing special about ubuntu's kernels per se' .

Your main problem won't be with building , more booting, It should compile fine but I wouldn't be surprised to be looking at a blank screen then your problem is monitoring the output....There's an option in the archos config to get early debug output over USB, I think there's some modification you need to make to the USB Cable, Quallenauge knows about that, he did it , I was ghetto and used adb for my debugging. which can be probably made to work when booting ubuntu but I'd go the correct route , I just have my wierd ways of doing things.

Another thing that spring to mind with android "specialisms". Android runs /init in the root directory ubuntu normally likes /sbin/init. This is something that is specified again in the kernel config using the kernel cmdline option , just something to be aware of... If anything else springs to mind I'll let you know.

So I suppose as you say, Just fool around and see what happens.



Just Checking LOL.

At the moment i'm trying to find the archos config file. there is a defcon file, which looks like a config file in arch/arm/configs called android_archos_defcon. It sounds correct. Next thing for me to do is to find the right place to put it. I guess the root of the project is correct, and rename it to .config and linux.config. After building I need to test it. ICS@BLUE4 or 4.0.26 root will suffice, right? I also need to figure out if there is a way to force adb on through kernel. And the IPv6 Mangling is nowhere to be found
10th December 2012, 09:31 PM |#8  
Quote:
Originally Posted by julle131

At the moment i'm trying to find the archos config file. there is a defcon file, which looks like a config file in arch/arm/configs called android_archos_defcon. It sounds correct. Next thing for me to do is to find the right place to put it. I guess the root of the project is correct, and rename it to .config and linux.config. After building I need to test it. ICS@BLUE4 or 4.0.26 root will suffice, right? I also need to figure out if there is a way to force adb on through kernel. And the IPv6 Mangling is nowhere to be found

The config file " linux.config.g9" should be in the root kernel directory, if it's not there then your on the wrong branch and you need to checkout the 3.0.21 branch explicitly using
Code:
git checkout linux-ics-3.0.21
If your using ICS builds to check with, which I probably recommend then don't worry about IPV6 managling , I don't think It's named that exactly but something like that!, For reference , I've just had a check the option is "Networking support/Networking options/Network packet filtering framework (Netfilter)/IPv6: Netfilter Configuration /Packet Managling"

You have to look pretty deep on some of these settings

As a test. Boot with a normal kernel configure your android debug options , then swap the kernels out , that should give you adb while booting, when I've tried to force adb on an uncofigured rom it got a bit confused with itself

If your struggling a bit with git, http://gitimmersion.com/ has a great tutorial you can step through in about 10 minutes to get the basics and get it configured a bit better

---------- Post added at 09:31 PM ---------- Previous post was at 09:20 PM ----------

EDIT: Make sure you building for arm as well
Code:
$ export ARCH=arm
$ export SUBARCH=arm
$ export CROSS_COMPILE=arm-eabi-
Reference: http://source.android.com/source/building-kernels.html
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10th December 2012, 11:04 PM |#9  
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Huuuh i'm late... most had been pointed out already.
Just to add this...
As you might know Android is put on top of a Linux base system more or less.
In most cases a kernel built for Android will suit most linux distributions as well.
Trevd already highlighted the main aspects.
The other way round is more evil... unmodified linux kernel (or a kernel set up to run well with Ubuntu) will refuse to boot up an Android system.
Some addon's on the default config may be nice though, depends on how the whole rootfs stuff is arranged in the end and if your system heavily depends on udev and stuff.
Keep track of the startup scripts at /etc/init.d.
It's good to have an extensive look at the /etc directory of your distribution image... to much to point at here.

The kernel may handle to boot into a lot of different scenarios.
On the Archos tablets initramfs plays an important role.
You may even tweak this jumpboard and locate your final rootfs on an USB stick if you like.
It's all about handling mounts, chroot and similar during start up.
There are limits on the Archos with stock loader though, because you might need to influence the kernel command line at a certain point.

I'm aware that this is not very specific but there are so many ways to set things up.
Just follow the useful links trevd gave already... these are good starting points

...and just to add this:
I don't speak of fine tune the system in the end. This is another story and sometimes very hard stuff, where you may need to reverse engineer some proprietary libs or executables.

Best regards,

scholbert
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12th December 2012, 07:05 PM |#10  
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Well, I have now built my first kernel... And it was 3.0.8+... I think I downloaded wrong source . I have ipv6 mangling enabled on it, so I should try it with CM10 now. I think I should search the 3.0.21 source, and download it.

Edit: Well, my 3.0.8+ Kernel image can boot CM10, AOKP and 4.0.7 roms... Now i have to figure out why i downloaded 3.0.8+ kernel and not 3.0.21 kernel. Maybe i had wrong branch.

Edit:Yep, wrong branch. I did realize when i downloaded the srce that it informed that the branch does not exists. i had icc instead of ics

Do you have any tips where i can find info about kernel modifications, like adding governors? I tried adding few, but all i got was bunch of errors. I propably forgot something.

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21st December 2012, 11:00 AM |#11  
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mer
Still working on this? I have been using Mer kernels with Ubuntu and they seem to be working fine.

Archos Gen9 Mer Adaptation Kernel --> http://gitorious.org/archos-gen9-mer-adaptation-kernel/
Archos Gen9 Mer Adaptation Kernel ICS --> https://gitorious.org/archos-gen9-me...ion-kernel-ics

I am using the 3.08 kernel from a Plasma Active distribution. --> http://share.basyskom.com/plasma-act...chos_gen9.html
Just mount the data partion in linux and convert it to ext4, write the linux image to it. Then cp the files from mer /boot /lib/modules to new rom, modules file in etc to load your modules, modify fstab, cp mtev.so to /usr/lib/xorg/modules/input, change or add a few other files.
/etc
modules
Code:
cypress_tma340
tr16c0_i2c
hso
compat
cfg80211
mac80211
wl12xx
wl12xx_sdio
cpt_i2c_tsp
pixcir_i2c_tsp
hci_uart
fstab
Code:
/swap	none	swap	sw	0 0
/dev/mmcblk0p2	/media/system	ext4	ro,noauto,users,uid=1000,gid=0,noatime	0 0
/dev/mmcblk0p4	/media/data	ext4	ro,noauto,users,uid=1000,gid=0,noatime	0 0
none /proc proc rw,relatime,noexec,nosuid,nodev 0 0
none /sys sysfs rw,relatime,noexec,nosuid,nodev 0 0
none /dev devtmpfs rw,mode=0755 0 0
none /dev/pts devpts rw,relatime,gid=5,mode=0620,ptmxmode=0666 0 0
tmpfs /tmp tmpfs defaults,noatime,mode=1777 0 0
binfmt_misc /proc/sys/fs/binfmt_misc rw,noexec,nosuid,nodev 0 0
none /sys/fs/fuse/connections fusectl rw 0 0
none /sys/kernel/debug debugfs rw 0 0
none /dev/shm	tmpfs	nodev,nosuid,noexec  0 0
none /dev/bus/usb	usbdevfs	defaults 0 0
none /sys/kernel/security	securityfs	(rw) 0 0
/etc/udev/rules.d
70-persistent-net.rules
Code:
# net device ()
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="08:00:28:90:64:31", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="wlan*", NAME="wlan0"
# USB device 0x9710:0x7830 (usb)
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="00:13:3b:04:02:6c", ATTR{dev_id}=="0x0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
70-touchscreen.rules
Code:
KERNEL=="event*", SUBSYSTEM=="input", SUBSYSTEMS=="input", ATTRS{name}=="cypress-tma340", SYMLINK="input/touchscreen"
/usr/share/X11/xorg.conf.d
Add to the end of 10-evdev.conf, cypress-tma340 is the touchscreen on my G9.
Code:
Section "InputClass"
    Identifier "Archos Touchscreen"
    MatchProduct "cypress-tma340"
    Option "Ignore" "off"
    Option "CorePointer" "on"
    Driver "mtev""
EndSection
openSUSE --> http://en.opensuse.org/openSUSE:eek:...your_ARM_board
Ubuntu --> https://wiki.ubuntu.com/ARM/OMAP
Kubuntu 12.10 --> http://cdimage.ubuntu.com/kubuntu/re...rmhf+omap4.img
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