On Sun, Feb 23, 2003 at 12:50:59AM +0200, guy keren wrote:
On Wed, 19 Feb 2003, Muli Ben-Yehuda wrote:
On Wed, Feb 19, 2003 at 11:58:16AM +0200, Eli Billauer wrote:
original configuration, and noone was really sure. I don't think that
there is someone here who can tell me exactly what files are tampered
with during all the makes (could syscalltrack be handy here? ;). All
this makes kernel compilation a mysterious adventure, with no promised
way back home. If there was as little as a list of directories to back
up before starting, it would all look different.
Eli,
It's not voodoo. It's not a mystery. It's code, plain and simple,
there for the reading. Please read the Makefile and write a
comprehensive list of files which are changed. I'm sure
kernelnewbies.org will be happy to put it on line.
actually, there's a contradiction there. if it was that simple, there
would be no need to write a doc for it and place on kernelnewbies.
I didn't say it's simple, I said it's code, plain and simple. as
in you have the documentation, it's the code.
Makefiles are usually hard-code to read, and writing Makefiles which are
easy to maintain as well as easy to read, is a difficult task.
specifically, the Makefiles of the linux kernel are not easy to figure.
the fact that you deal with them for quite some time now, and you read
them rather easily, is not an evidence to how easy it is to read them for
the first time. this is especially tru when you have a specific goal in
mind (such as - how do i get this module to work).
I agree here.
Don't take me wrong: I think that the possibility to compile the kernel
is one of the beauties of Linux, and writing in kernel space is
something I know I'll do sooner or later. The problem is that it's such
an unfriendly field, and for no real reason.
Did you read the books? did you read the source? where else did you
expect the knowledge to come from?
from good documentation, ofcourse. the linux kernel comes with lots of
documentation, but without something large to show the architecture of the
beast, and how it all fits together. specifically, i'm not aware of good
documents that deal with the Makefiles - is there? for the kernel itself
there is 'the linux kernel' in the Linux Documentation Project - thoughts
its not deep enough for my taste.
Linux Device Drivers, 2nd Edition (available online). Understanding
the Linux Kernel, 2nd Edition (highly recommended). The linux-kernel
mailing list archives. The lwn.net kernel summaries (very highly
recommended), and kernel traffic. http://www.kerneltrap.com,
http://www.kernelnewbies.org.
As for the Makefiles specifically, in 2.5, 'make help' should be a
pleasant surprise, the Makefile begins with a documentation section
and there is Documentation/kbuild/*. 2.4 is not quite as well endowed,
but neither is it completely lacking.
c. Run 'make oldconfig; make dep'. This step prepares the intermediary
kernel configuration and build files that are needed for the build
process. Amongst other things, it handles module version.
Thanks. make oldconfig was the secret. And a secret it is. Just for
the fun of it, does anyone know exactly what it does? What old
configuration are we talking about? And make dep afterward fixed
it all.
It takes .config, all of the configuration symbols in this kernel, and
only asks you about new or changed configuration options. It's used
when you already built a kernel, and then a new version is
released. You copy the same .config over and run 'make oldconfig', and
instead of dealing with hundreds of configuration options, you only
deal with the delta.
As a side effect, it also creates some files that tell the build
system that it has been configured, and (I think) creates the
include/asm-$(ARCH) - include/asm symlink.
just as a note - i have been compiling linux kernels for several years,
before i heard about 'make oldconfig' for the first time - and i did read
some of the documentation that comes with the kernel during that time. in
fact, i got so used to reconfiguring it manually, that i keep forgetting
about 'make oldconfig', and thus configuring a new kernel keeps taking me
30-60 minutes every time ;)
You should start doing it 15 or 20 times at a stretch, that will cure
your memory in a hurry ;-)
Here's my currently running kernel:
[EMAIL PROTECTED]:~$ uname -a
Linux tea 2.5.62-mx #34 SMP Sat Feb 22 09:28:42 IST 2003 i686 unknown
the #34 there means that it's the 34th compilation of this kernel
tree...
Start with the top level
Makefile and Rules.make, and follow what happens when you run 'make
oldconfig; make dep'.
Yeah, right. I wanted to install a linmodem driver, not explore the
mysteries of makefile, sed and bash, and virtually every possible system
file.
You want knowledge. I told you where it is found.
