I'm trying to build linux kernel for arm64 using buildroot. All my builds end without -generic suffix (uname -r ) but when I checked official ubuntu kernel they end with -generic. I searched buildroot manual etc. but I couldn't find related information.
So how can I build a generic kernel ?
This additional -generic string is not very important, it's just a free form string that you can append to the kernel version. This free form string is specified in the kernel configuration, with the CONFIG_LOCALVERSION option.
Related
I need to know the version of a kernel file without running it. Therefore, the following questions arise in this realm:
Is it possible to get the kernel version in the u-boot environment? I mean before running the kernel I want to get the version of my kernel file.
Suppose I am running ubuntu on my amd64 processor and I have a zImage file which is cross compiled for ARM processor. Therefore I can not run this zImage file on amd64. Then how can I get version of this zImage file without running it on an ARM processor? I checked out uname manual but it does not accept a file as argument. I also issued readelf -V on a vmlinux kernel file, but it was an unsuccessful attempt.
I'm trying to config my kernel (2.2.0) but when I use make menuconfig make says: No rule to make target 'arch/x86_64/Makefile'. It is a wrong response because there is no directory named x86_64 in arch. Is there a problem with the kernel tree?
The source of my kernel tree can be found here
The "problem" is that the x86_64 architecture was not yet supported in 1999. You simply need to get a kernel from this millennium if you want to target this architecture, or painstakingly backport the necessary code changes to support it from a newer version.
I want to build a application which supports eBPF on CentOS 7 (the kernel version is 3.10.0):
if(setsockopt(sock, SOL_SOCKET, SO_ATTACH_BPF, prog_fd, sizeof(prog_f)) {
......
}
So I download a 4.0.5 version, make the following configurations on:
CONFIG_BPF=y
CONFIG_BPF_SYSCALL=y
Then follow this link to build and install a 4.0.5 kernel.
After executing make modules_install install, I find there is still no SO_ATTACH_BPF in <asm-generic/socket.h>, so the above code can't be compiled successfully.
How to build Linux kernel to support SO_ATTACH_BPF socket option?
In my setup, which is based on Fedora 21, I use very similar steps to those you linked to compile and install the latest kernel. As an additional step, I will do the following from the kernel build tree to install the kernel header files into /usr/local/include:
sudo make INSTALL_HDR_PATH=/usr/local headers_install
This will cause both the stock kernel header files to remain installed in /usr/include/{linux,asm,asm-generic,...}, and the new kernel header files to be installed in /usr/local/include/{linux,asm,asm-generic,...}. During your test program compile, depending on which build system you use, you may need to prefix gcc/clang with -I/usr/local/include.
Your newly installed kernel supports SO_ATTACH_BPF, but your current libc package doesn't now about that (as you mention, distro's native 3.10.0 kernel lacks of given option support).
You need to update libc package as well for use new kernel's features in user space programs.
I am a beginner learning linux kernel module development. I am following a tutorial that says to recompile my kernel so as to enable various debugging features like forced module unloading e.t.c. Is is okay if I do that? Does it effects my pre-built kernel. In what cases that I am forced to insert a module into a running kernel and the kernel won't allow me to do so?
It is perfectly okay to compile and install a kernel to do kernel module development. If you are in ubuntu, you can follow the following steps to make sure that you are using the same kernel sources as your booted machine.
Step 1. Find out the linux being used in your booting from /boot/grub/grub.cfg file. Look for the entry agains 'linux ' in the boot option entries that you select while booting up.
Example excerpt : linux /boot/vmlinuz-3.13.0-24-generic root=UUID=e377a464-92db-4c07-86a9-b151800630c0 ro quiet splash $vt_handoff
Step 2. Look for the name of the package with the same version using the following command.
dpkg -l | grep linux | grep 3.13.0-24-generic
Example output:
$ dpkg -l | grep linux | grep 3.13.0-24-generic
ii linux-headers-3.13.0-24-generic 3.13.0-24.46 amd64 Linux kernel headers for version 3.13.0 on 64 bit x86 SMP
ii linux-image-3.13.0-24-generic 3.13.0-24.46 amd64 Linux kernel image for version 3.13.0 on 64 bit x86 SMP
ii linux-image-extra-3.13.0-24-generic 3.13.0-24.46 amd64 Linux kernel extra modules for version 3.13.0 on 64 bit x86 SMP
Step 3. Download sources of the package "linux-headers-3.13.0-24-generic" to get the same kernel that was used in your PC.
$ apt-get source linux-headers-3.13.0-24-generic
Step 4. Use the config file that is available at /boot/ folder as the config file to compile this kernel source
Example :
$ ls /boot/config-3.13.0-24-generic (Notice the same version used in this file)
Step 5. Turn on your debugging symbols on this config to do your testing.
Recompiling kernel help us to learn how kernel work.
latest kernel patches can be applied through kernel compile and install.
We can enable debug flag through compilation.
We can remove the not needed code.
Helps to add your own kernel code and test your code.
It is easy to recompile and install the linux kernel but it takes more time if we compile using low speed computer or VM.
However I Cross Compiled ARM Kernel instead of ARMHF(for my Cubietruck). I followed this tutorial:
https://romanrm.net/a10/cross-compile-kernel
How can I determine for which architecture I´m cross-compiling?
i got a new error that /linux/utsrealease.h is not found
from above comment as you mentioned.. from that its clear that kernel module which your building must match with running kernel version . As kernel modules loading mechanism doesn't allow loading modules that were not compiled against the running kernel, due to mismatch error is coming.
The macro UTS_RELEASE is required by your driver in order to rebuild
kernel modules from source.
retrieving the version string constant,
older versions require you to include<linux/version.h>,
others <linux/utsrelease.h>,
and newer ones <generated/utsrelease.h>
So my suggestion you do workaround by doing
you can find utsrelease.h in kernel source code make sure your running kernel must match with your source-code
copy linux-x.x.x/include/generated/utsrelease.h to installed header i.e ../include/linux/utsrelease.h
Im not sure give a try .
If above doesnot work pls update your question with
1)which kernel sourcode version you have
2)Whats the kernel version running on target
When you compile your kernel, mention the architecture you are compiling for in:
make ARCH=arm CROSS_COMPILE=arm-linux-gnueabihf- EXTRAVERSION=-custom1 uImage
For eg, here ARCH=arm, so you are compiling for ARM, if it's x86, then you'll replace it with x86. Check what architecture your target board is on.
EDIT: gnueabihf is for armhf.