I tried several times to recompile Linux kernel, everything worked fine, but i realized that its taking a lot of space from the hard disk , i would like to know where the newly compiled kernel files located? and is there any temporarily folders that i can clean manually? any files i can safely remove to free up some space ?
I downloaded the kernel source code, copied my kernel Config from /boot/
to the kernel source code
edited it using:
make menuconfig
make
make install
Related
I want to get the kernel defconfig of a Android Mediatek device with closed kernel source with android nougat. (for kernel bringup)
I tried looking for /proc/config.gz it does not exist. Likely cause the kernel was built with CONFIG_IKCONFIG_PROC off.
I tried using https://github.com/torvalds/linux/blob/master/scripts/extract-ikconfig on zImage. No luck. Probably because CONFIG_IKCONFIG was off, since google does not require that for anything lower than android oreo.
Are there any other ways to get the config or is this it? I didn't find any other way so decided to ask here.
I'm trying to apply a patch to my kernel source with limited success. The target machine is really some ARM device, but I haven't compiled a kernel before so I thought I'd start with an x86_64 kernel. This has been only marginally easier :)
Now, according to some tutorials, it seemed like we should use the source in /usr/src/linux-something. But when I tried to patch there I got
File Documentation/sysrq.txt is read-only; trying to patch anyway
patch: **** Can't create temporary file Documentation/sysrq.txt.oG1oiZW : Permission denied
even under sudo. So I tried just copying the patch and the linux source folder to my home directory and patched it from there. This worked. Why is this and will this have any weird side effects when compiling?
It seems you have no permission to /usr/src/linux-something. Download kernel source, put it anywere you could, then patch & compile it.
Build a x86_64 arch kernel from source which downloaded from kernel.org is well, if you wanna build an arm arch kernel for a special board, use buildroot or openwrt is better.
The package manager for some distributions installs the kernel source in /usr/src and distribution-specific build scripts may assume that the source is in that directory.
However, if you download vanilla kernel source from kernel.org, you should be able to build it anywhere.
I have a zImage file of a linux kernel 2.6.32.2 that someone sent me. I dumped onto my mini2440 board and it works fine there. Now, I would like to do the same for my host PC so that I can configure the kernel using the zImage that I have, since it has a few files that were missing from my earlier kernel.
How do I go about doing this?
Thank you,
Regards
I've got a Raspberry PI with Emdebian installed on it, and want to cross-compile projects.
There is plenty of documentation on how to obtain a toolchain and build a simple project with it. I myself managed to build a toolchain with crosstool-ng and wrote a hello world program which works fine.
What I don't get is how to handle cross-compiling more complex projects like Qt, which have dependencies on other libraries. Let's use libdbus as an example, as that is one of Qt's dependencies.
The installed Emdebian already contains libdbus.so, so naturally I'd prefer to use that, instead of cross-compiling my own libdbus.so, as compiling all of Qt's dependencies would take a lot of time.
For cross-compiling, there are two important directories, as far as I understand:
The "staging" directory, where all the installed libraries and applications live. This initially is a copy of the toolchain's sysroot directory, and gets populated with more libraries as they are cross-compiled.
The "rootfs" directory, which is equivalent to what is on the device - essentially a copy of the staging directory without unneeded stuff like documentation and header files. As far as I understand it, the best approach is to copy required files from the staging directory into the rootfs.
Getting the rootfs directory is easy, as that can be a NFS mount from the device. But how do I get a staging directory for the existing Emdebian installation on the PI? The staging directory needs to include things like dbus headers, which are not installed on the rootfs.
Some people simply install the dbus headers on the device, with apt-get install libdbus-dev, and then use the rootfs as the staging directory. With this setup, there is no distinction between rootfs and staging anymore, with the disadvantage that the rootfs is polluted with headers, documentation and so on. The advantage of course is that it is easy.
What is the best way to get the dbus headers into my staging directory on my host machine? What is the usual approach people use in this situation?
As a side question, why does the approach of obtaining a toolchain, compiling a program and then copying that on a target work at all? The toolchain ships its own versions of libc, libstdc++ etc, are they not incompatible with the versions that are installed on the target? Especially when creating using a custom toolchain compiled with crosstool-ng?
(Note that I am not asking how to compile Qt, I can figure that out myself. My question is more general, about the approach to take when combining a custom toolchain with an existing installation/rootfs)
In my experience, you don't need to compile your dbus. You can do it as
Create Debian cross rootfs by debootstrap by https://wiki.debian.org/EmDebian/CrossDebootstrap
Create your cros-compile toolchain by crosstool-ng, and make sure the kernel version and eglibc version are the same as rootfs created by 1st step
Build QT by
CPPFLAGS=-I<rootfs>/usr/include \
LDFLAGS=-L<rootfs>/lib -L<rootfs>/usr/lib -Wl,-rpath-link,<rootfs>/lib,<rootfs>/usr/lib \
./configure <your options>
make
Install QT into the stage directory by
make install DESTDIR=<stage directory>
Copy QT dependent libraries from rootfs the your stage directory
So you can see that, the stage directory is kept minimum without pollution.
This is my first time compiling Linux kernel. I am using Debian Live. I used kernel-package to compile and I also added a new system call to return an arbitrary integer value greater than zero.
Everything went fine and I got both headers and image .deb files. When I tried to install them with dpkg, there was a warning that said I needed to configure LILO. I then aborted the installation and looked for LILO to find out that Debian Live got neither LILO nor GRUB. I installed GRUB, but it was not installed on my sda1 (USB disk running Debain Live), it said that it was not a proper block device. Debian Live uses squashfs (a file system).
Then, I ignored bootloader and installed the custom kernel. After I rebooted my computer, I was directly booted to the old Debain Live and my system call returns -1.
Please provide some solutions guys.
Thanks,
Debian Live is not a suitable base for you do to your own kernel development on. As you've found, it doesn't contain the tools needed to rebuild itself (that's not what its designed to do).
Install the regular Debian distribution (perhaps inside a virtualisation environment like VMWare Server or VirtualBox). Do your kernel development there.