On Fri, Mar 01, 2019 at 04:03:09PM +0900, Masami Hiramatsu wrote:
Hi Joel,
On Thu, 28 Feb 2019 22:26:11 -0500 Joel Fernandes joel@joelfernandes.org wrote:
On Fri, Mar 01, 2019 at 11:28:26AM +0900, Masami Hiramatsu wrote:
[..]
There are many usecases for this, I have often run into issues with Linux over the years not only with Android, but other distros, where I boot custom kernels with no linux-headers package. This is quite painful. It is convenient to have it as /proc file since the file is dependent on kernel being booted up and this will work across all Linux distros and systems. I feel that if you can keep an open mind about it, you will see that a lot of people will use this feature if it is accepted and there is a lot of positive feedback in earlier posts of this set.
I don't complain about having headers for custom boot kernel. I agree with you that having kernel headers for debugging is always good. :) So google recommends built-in, it is reasonable.
Ok, thanks :)
The code to read the headers is based on /proc/config.gz code and uses the same technique to embed the headers.
To build a module, the below steps have been tested on an x86 machine: modprobe kheaders rm -rf $HOME/headers mkdir -p $HOME/headers tar -xvf /proc/kheaders.tar.xz -C $HOME/headers >/dev/null cd my-kernel-module make -C $HOME/headers M=$(pwd) modules rmmod kheaders
It seems a bit complex, but no difference from compared with carrying kheaders.tar.gz. I think we would better have a psudo filesystem which can mount this compressed header file directly :) Then it becomes simpler, like
modprobe headerfs mkdir $HOME/headers mount -t headerfs $HOME/headers
And this doesn't consume any disk-space.
I felt using a compressed tar is really the easiest way because of all the tools are already available.
As I asked above, if the pure tarball is useful, you can simply ask vendors to put the header tarball on their vendor directory. I feel making it as a module is not a right way.
I don't see what is the drawback of making it a module, it makes it well integrated into kernel build and ecosystem. I also didn't see any justification you're providing about why it cannot be a module. If you go through this and earlier threads, a lot of people are Ok with having a module option. And I asked several top kernel maintainers at LPC and many people suggested having it as a module.
I meant, if we have a tarball, we don't need any operation of loading/unloading kmodules. But if we have this as built-in, yes, this would be much easier to deploy it to device.
Anyway, having that option (make it as a module) is not bad. IMHO, that may be more complicated than just have a tarball file, but it is a user's choice.
OK, now I understand it.
Sounds good. :) Just sent out v4.
thanks,
- Joel