I am compiling my own Linux kernel and userland tools for a PXE environment meant for cloning and reimaging. Right now, I'm sticking to a specific kernel version and using preconfigured .config's for building the Linux kernel.
I need to change from using preconfigured .config's to automatically generating the default configuration for the specified architecture, and then enabling all ethernet, ATA, SATA, and SCSI drivers.
The reason I want to do this is:
Updating the kernel means updating the preconfigured .config's, which takes too much time to manually do. The way I'm doing it now is using menuconfig, enabling the options I need, and saving the resulting .config to my repository.
I know the kernel I'm building is missing some drivers because I've encountered some PC's that were not able to mount the NFS share because Linux could not find an ethernet device (which I've verified by booting an Ubuntu CD, which did find the ethernet device). I want an automated way of building any Linux kernel version that will guarantee that ALL drivers I need are pulled in.
Using a distribution's configuration pulls in too many unnecessary drivers and features for my purposes. It lengthens the kernel build time from 10-15 mintues to an hour or more, and the resulting image is too big.
Does anyone know how to write a Bash script to accomplish this?
Have you considered using a text editor to modify the .config file.
Then you can modify it using search and replace.
Plus, there are other choices for configuring the kernel than the menu-driven "menuconfig".
Related
I may have a couple assumptions of Linux incorrect about the Linux system, and for that I apologize.
I have been educating myself on the Android and Linux systems for a while now and I started looking into installing a custom boot loader and Linux system onto an older Samsung tablet. Immediately upon looking into the feasibility of this, most of the answers I could find were that it wasn't possible because you would need the drivers that are being used by the android kernel to communicate with the OEM hardware in whatever Linux kernel you are installing.
I have one of these tablets rooted and I believe I may have found the drivers I need (not sure on that yet), and so I guess my question is, is it possible to take the drivers and put them into a Linux kernel within a distribution install image and install Linux on the device (using also a custom boot loader)?
I presume because someone hasn't done this before there is a pretty good reason why, but I am basically looking to be able to use Linux on my old tablet without the resources being taken from Android, and personally in my opinion, if I don't need Android and can install Linux straight on to the machine, then why keep it?
In the long run I am looking into LFS to create a custom distribution that can be installed on these tablets, but the most important question to me right now is if I do create this distribution can I get the drivers that the hardware needs (and even then will my kernel be able to use them?).
I also understand that some of these drivers may be proprietary drivers provided by the manufacturer, but I am not looking to profit off of this but instead research the feasibility of a better personal on-the-go computing setup.
I may be terribly wrong on how I may have described some things, so here are some of my assumptions:
The .ko files in the Android /lib/modules/ directory are the static kernel drivers I am looking for for that device.
The drivers aren't written for specifically the Android system, but for all Linux variants and would be compatible with another distribution.
If the drivers were written for the Android system, then one would be able to edit or modify those drivers to work with a different distribution.
One could "put the drivers into an installation image", or if not, then one would have to compile the kernel from source with those static drivers.
TL:DR, If this all just amounts to rambling, here are my specific questions:
Is it possible to copy the static kernel drivers of a rooted Android device to something like the SDcard?
Is it then possible to "put" or "compile" those same static drivers into a Linux distribution before installing it onto said tablet using something like Odin, or the like?
I want to make a bootable emergency USB-stick that automatically repartitions my system and unpacks a rootfs to the hard disk, installs the bootloader, etc.
I compiled my own kernel and created my own initrd with various scripts.
this works very well. only booting from an USB-stick causes problems when secureboot is active.
to work around the problem I took an official Ubuntu livecd and copied all the content like isolinux/ EFI/* and so on, I changed all grub-configuration-boot-entrys to my kernel and my initrd. So I think the bootloader should be secureboot capable.
i set the following parameters in grub.cfg and built a new iso:
set check_signatures=no
if secureboot is disabled, the system boots correctly.
if secureboot is active, the bootloader can be loaded. so the secureboot is done? but then the process aborts with the following error:
invalid signature: /boot/bzImage
although set check_signatures=no is set.
Does anyone have an idea?
Is there no other way than to sign my kernel and distribute the keys across all systems? - can I distribute the key via ssh without direct access to the hardware?
problem solved with signed-shim bootloader, free to download
EDIT: As stated in the comments, the question seems too broad to answer, so I'll leave the explanation of the problem and the questions, because they haven't changed, but I have changed the title (it doesn't seem good yet, but it's better than before) so they are more in tune.
What lead me to the question
I want to compile OpenWRT for my board. At the moment I am compiling it to a beagle bone black, and it's quite straight forward since there are tutorials available for that, but it got me thinking. How would I build it for a completely bare board? Like it or not BBB comes with u-boot and a version of linux (Amstrong if I'm not mistaken) so when I build OpenWRT for it maybe many things have already been taken care of for me.
I know that I need to first set up the board to boot from somehere, then it must have the bootloader and finally the kernel (there is the SPL and all that, but ok, let' leave it aside for now).
Hypothetical system
Let's imagine I have a hardware similar to the beaglebone, except it has a dipswitch connected to the boot pins in order to select from where I'm going to boot my device from. Imagine I have set it to boot from ethernet, which means that on startup a bootloader located in ROM will receive a binary file and store it in flash, all that via TFTP.
The questions
At this point I imagine that the binary file given via TFTP is the bootloader, am I right?
So after that I'd need to give the bootloader the kernel?
Does this mean that it is a 2 step process? First load the bootloader an dthen the kernel?
Is it possible to compile both at the same time and load it into the microprocessor?
Does OpenWRT build u-boot as well or do I need to compile it separately? I know it downloads the kernel and compiles it.
How would I build this for production? Imagining that I have to build u-boot and openwrt separately, would I create a script that compiles both and then does the entire process of downloading it into the microprocessor?
Is it possible to pre-configure the kernel so that it doesn't need to be configured after the code is downloaded? I mean, for example, compile it with initialization scripts instead of connecting to the device and configuring this. Is it possible or do I have to connect to the board and configure it manually?
PS: Sorry for such basic questions, but it's my first time compiling the kernel for real, and I've only worked with microcontrollers and RTOSs at most
Let's try to answer the queries one by one
At this point I imagine that the binary file given via TFTP is the bootloader, am I right?
No, It should be the firmware(kernel+HLOS). TFTP is available in uboot or only after SBL(Secondary boot loader) is loaded into memory.
So after that I'd need to give the bootloader the kernel?
bootloader needs to be present in the memory and if required it can get the firmware from ethernet, This can be simply done by changing the uboot env(bootcmd), can also be configured at compile time.
Does this mean that it is a 2 step process? First load the bootloader an dthen the kernel?
Yes, bootloader needs to be loaded earlier, but if you designing a custom board, you can combine the images in a big file and then flash/load that file at once.
Is it possible to compile both at the same time and load it into the microprocessor?
Does OpenWRT build u-boot as well or do I need to compile it separately? I know it downloads the kernel and compiles it.
Yes, Openwrt is very flexible and it compiling uboot, kernel, userspace package at once and create a desired image(based upon user configuration).
How would I build this for production? Imagining that I have to build u-boot and openwrt separately, would I create a script that compiles both and then does the entire process of downloading it into the microprocessor?
You can configure the openwrt to generate the appropriate image(based upon the flash and system requirement) and then flash that image in production(so, simple).
Is it possible to pre-configure the kernel so that it doesn't need to be configured after the code is downloaded? I mean, for example, compile it with initialization scripts instead of connecting to the device and configuring this. Is it possible or do I have to connect to the board and configure it manually?
Yes, use make kernel_menuconfig to configure the kernel parameter at compile time.
Hope, I have answered all the queries!!!
With the default Debian installation in a BeableBone Black you can access it via USB as different devices: mass storage device, virtual ethernet and virtual serial uart. This is accomplished with the g_multi module. You can review its configuration via files in /sys/module/g_multi/parameters/ .
I am trying to use it only as a mass storage device but with other disk/block device, not the second partition in the boot block device. I have checked that it is always the same partition not matter if it is /dev/mmcblk1p2 (when I have a microSD inserted on boot) or /dev/mmcblk0p2 (without it). I have tried removing g_multi after boot and modprobing g_multi or g_mass_storage with my own configuration, and it works OK.
But I don't want the default configuration to load on startup, so I need g_multi to not load at all, or to load with my own parameters.
I search for its configuration in every place I could think of: configuration for modules in /etc, configuration for systemd, parameters of uboot for kernel, decompiling dtbs, and even with a compiled kernel I searched for the manufacturer that the startup g_multi shows in its /sys/module/g_multi/parameters/iManufacturer in all the files.
I am not able to find anything. Could someone help me?
Thank you very much in advance.
I have finally found it. It is a bit hidden (in a Debian perspective).
It is configured in the /opt/scripts/boot/am335x_evm.sh script.
I had forgotten all those scripts and utilities for the Beagle platforms. I had to follow the major part of the boot proccess.
I'm complety new to this but I finally got around to building a Linux kernel so far so good. I am following a guide here:
A10-OLinuXino-LIME
My problem/concern is now I am in a .config menu and I've been searching online to no avail to determine what does it mean by a modularizes features verse includes, like should I switch to if I want those features to be there?
Any help or advice would be greatly appreciated it! I'm primarily doing this to include WiFi usb drivers I will be needing.
It depends on what system you run this kernel. If it's an embedded system, then you will probably be more concerned about memory benefits. In RAM you can win about several Kbytes per module. For the devices are not represented in the system/hardware, it then has a sense to put some drivers on Modules. Some modules can be taking more time when the kernel starts, and it is probably better to load them later, when the system is running.
You will probably be concerned about disk space, if you put some stuff Compiled-in so you can have a benefit because you don't need to have a module loading utility.
Have a look at this thread as well
I'm primarily doing this to include WiFi usb drivers I will be needing.
Its not necessary to build the complete kernel unless to build a USB WiFi driver. All you need is the kernel headers installed. From make menuconfig select the module you want to build, choose M, save the .config. This will build a module which can be loaded, instead of getting compiled as a part of the vmlinux image.