[gentoo-user] modules built post kernel install (on the fly)

[gentoo-user] modules built post kernel install (on the fly)

[Harry Putnam]

Is this possible:

Compile a module by itself (not during kernel compile) and insert
that module into a running kernel.

I'm pretty sure this is possible but have no idea how to do it.
Pawing thru google. `site:gentoo.org modules "on the fly" ' and
similar strings .... even just `kernel module'

Turns up scads of stuff but none of it is hitting this head on.. or I
didn't paw far enough.... so asking here for pointers to documentation
that will cover this.


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[gentoo-user] Re: modules built post kernel install (on the fly)

[Peter]

On Sat, 04 Mar 2006 09:15:04 -0600, Harry Putnam wrote:

> Is this possible:
> 
> Compile a module by itself (not during kernel compile) and insert that
> module into a running kernel.
> 
> I'm pretty sure this is possible but have no idea how to do it. Pawing
> thru google. `site:gentoo.org modules "on the fly" ' and similar strings
> .... even just `kernel module'
> 
> Turns up scads of stuff but none of it is hitting this head on.. or I
> didn't paw far enough.... so asking here for pointers to documentation
> that will cover this.

Yes.

cd /usr/src/linux
make menuconfig or make xconfig
choose the module option you wish to enable
Select whether to build into the kernel or as a module.
exit and save
make
make modules_install

You should not have to copy bzImage unless you built your new modules into
the kernel.

Then edit your /etc/autoload directory to include the module you want to
modprobe into the system.

easy!

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[gentoo-user] Re: modules built post kernel install (on the fly)

[Harry Putnam]

Peter <pete4abw@comcast.net> writes:

> Yes.
>
> cd /usr/src/linux
> make menuconfig or make xconfig
> choose the module option you wish to enable
> Select whether to build into the kernel or as a module.
> exit and save
> make
> make modules_install
>
> You should not have to copy bzImage unless you built your new modules into
> the kernel.

Haa... thanks for the step thru... and I'm guessing if you don't want
to reboot you can insmod this module into running kernel?

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[gentoo-user] Re: modules built post kernel install (on the fly)

[Peter]

On Sat, 04 Mar 2006 09:35:35 -0600, Harry Putnam wrote:

> Peter <pete4abw@comcast.net> writes:
> 
>> Yes.
>>
>> cd /usr/src/linux
>> make menuconfig or make xconfig
>> choose the module option you wish to enable
>> Select whether to build into the kernel or as a module.
>> exit and save
>> make
>> make modules_install
>>
>> You should not have to copy bzImage unless you built your new modules into
>> the kernel.
> 
> Haa... thanks for the step thru... and I'm guessing if you don't want
> to reboot you can insmod this module into running kernel?

That is correct. Unless you alter bzImage, modprobe newmodule should work
just fine. If your new module is built in, you will need to reload the
kernel (reboot).

Good luck!


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[gentoo-user] Re: modules built post kernel install (on the fly)

[Harry Putnam]

Peter <pete4abw@comcast.net> writes:

> That is correct. Unless you alter bzImage, modprobe newmodule should work
> just fine. If your new module is built in, you will need to reload the
> kernel (reboot).

Ok, this is confusing to me... What do you mean by `built in'.  I'm
thinking the very nature of a module is that it isn't built in.

Or do you just mean I'd chose `*' instead of `m' and move bzImage into
place in /boot?

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Re: [gentoo-user] Re: modules built post kernel install (on the fly)

[Brett I. Holcomb]

Builtin means it's built into the kernel - the * indicates that.

On Saturday March 4 2006 23:03, Harry Putnam wrote:
> Peter <pete4abw@comcast.net> writes:
> > That is correct. Unless you alter bzImage, modprobe newmodule should work
> > just fine. If your new module is built in, you will need to reload the
> > kernel (reboot).
>
> Ok, this is confusing to me... What do you mean by `built in'.  I'm
> thinking the very nature of a module is that it isn't built in.
>
> Or do you just mean I'd chose `*' instead of `m' and move bzImage into
> place in /boot?

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Re: [gentoo-user] Re: modules built post kernel install (on the fly)

[Holly Bostick]

Harry Putnam schreef:
> Peter <pete4abw@comcast.net> writes:
> 
>> That is correct. Unless you alter bzImage, modprobe newmodule 
>> should work just fine. If your new module is built in, you will 
>> need to reload the kernel (reboot).
> 
> Ok, this is confusing to me... What do you mean by `built in'.  I'm 
> thinking the very nature of a module is that it isn't built in.
> 
> Or do you just mean I'd chose `*' instead of `m' and move bzImage 
> into place in /boot?
> 
(Most) kernel modules can be either built into the kernel, or separately
from the kernel. Only a very few can only be builtin or only loadable. But
whichever they are, they're really all modules-- the kernel is a modular
framework, after all, which is why you have to configure it-- to say
which kernel modules you want to build, and how you want them built (as
builtin to the kernel, or as separate loadable modules).

If they're built into the kernel "body" ("*"), they're called
"built-in", in which case they are an integral part of the bzImage, and
increase the size of the kernel. Builtins will also always be loaded by
the kernel just because they're part of the kernel; this is why you must
build certain modules (like for filesystems) as builtins and not as
modules, so the kernel has them loaded before it needs them to read the
relevant filesystem.

If the modules built as dynamically loadable modules ("M". which
produces little chunks of code-- *.ko files, I think-- in
/usr/lib/modules/<kernel_version> when you run make modules_install),
they are called "modules" (or loadable modules, or dynamic modules). In
this case, they 1) do not increase the size of the kernel (because
they're not in the bzImage that is the kernel), 2) they are dynamically
loadable (modprobe) and removeable (modprobe -r), and may or may not
exist at all (because you have the ability to pick and choose which
loadable modules you actually want to build in your kernel config).

So what Peter meant was that if you add the modules as loadable modules
(by choosing "M"), you wouldn't have to do anything other than make and
make modules_install to install the new module (you need to do a make so
that the kernel config knows that there's a new module *to* make), but
because the body of the kernel has not actually changed (since loadable
modules are not compiled into the bzImage like the builtin * modules
are), you don't actually have to install the new bzImage, because it's
exactly the same as the one you had previously installed. You should be
able to modprobe the new module and go right on without rebooting.

However, if you compiled the new modules directly into the kernel (by
choosing "*", or compiling a module that has a sub-function that
requires a *), then you would have to install the new bzImage and
reboot, because the bzImage (the kernel) has actually changed.

Hope this helps explain things,
Holly
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[gentoo-user] Re: modules built post kernel install (on the fly)

[Harry Putnam]

Holly Bostick <motub@planet.nl> writes:

> So what Peter meant was ....]

[...]


Yeah thats what I suggested it meant.  I added some unnecessary
confusion by saying `the very nature of module is that it is not built
in'...  sorry.  Just sloppy thinking here thanks for clearing that up
very well.

But since my original question was:

  [How to -ed HP] "Compile a module by itself (not during kernel
  compile) and insert that module into a running kernel."

That would rule out `*' so that's why it confused me.

> However, if you compiled the new modules directly into the kernel (by
> choosing "*", or compiling a module that has a sub-function that
> requires a *), then you would have to install the new bzImage and
> reboot, because the bzImage (the kernel) has actually changed.

Nothing different really than just compiling a kernel....

In fact it sounds like the whole process is required for adding
a new `loadable' module too, just leaving out the moving of bzImage. 
And no reboot required.

I guess I sort of thought there was some trick way to just compile a
module and not do all the linking and grinding of `make' against the
whole tree.

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Re: [gentoo-user] Re: modules built post kernel install (on the fly)

[Ryan Tandy]

Harry Putnam wrote:
> I guess I sort of thought there was some trick way to just compile a
> module and not do all the linking and grinding of `make' against the
> whole tree.
>   
Unless you've done 'make clean' previously, 'make' will only compile 
required files based on changes you've made to your config.  My laptop 
runs a monolithic kernel with very few modules (PCMCIA and USB 
hotplugged stuff), but as long as I'm not changing versions, adding or 
removing features usually only involves compiling a few source files and 
linking the bzImage.

If you just want to build new modules and haven't made any changes to 
the actual kernel, 'make' can be left out since the bzImage doesn't need 
rebuilding - 'make modules modules_install' will be sufficient to build 
and install your newly selected modules.

If you've run 'make clean', which removes all previously compiled 
objects, a monolithic kernel will have to be rebuilt from scratch - but 
once again, running only 'make modules modules_install' will rebuild all 
your modules but leave the kernel itself alone.

HTH.
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Re: [gentoo-user] Re: modules built post kernel install (on the fly)

[Masood Ahmed]

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Peter wrote:
> On Sat, 04 Mar 2006 09:15:04 -0600, Harry Putnam wrote:
> 
> > Is this possible:
> > 
> > Compile a module by itself (not during kernel compile) and insert that
> > module into a running kernel.
> > 
> 
> Yes.
> 
> cd /usr/src/linux
> make menuconfig or make xconfig
> choose the module option you wish to enable
> Select whether to build into the kernel or as a module.
> exit and save
> make
> make modules_install
> 
> You should not have to copy bzImage unless you built your new modules into
> the kernel.
> 
> Then edit your /etc/autoload directory to include the module you want to
> modprobe into the system.
> 

This sounds simpler than what i had thought. I suggest giving this a
try. My earlier suggestion to read the Makefiles has been taken back
now.. :)

-- 
Linux Kernel  : 2.6.15-gentoo-r7
GCC version   : 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8)
Processor     : AMD Athlon XP 2600+
RAM           : 1 GB DDR 333 SDRAM
CFLAGS USED   : -march=athlon-xp -O3 -m3dnow -msse -mmmx -pipe
                -fomit-frame-pointer -momit-leaf-frame-pointer -ftracer
	        -fno-crossjumping -falign-functions=16 -falign-loops=16
	        -falign-jumps=16 -fno-align-labels -mfpmath=387,sse
	        -maccumulate-outgoing-args
CXXFLAGS USED : $(CFLAGS) -fvisibility-inlines-hidden

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Re: [gentoo-user] modules built post kernel install (on the fly)

[Masood Ahmed]

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Harry Putnam wrote:
> Is this possible:
> 
> Compile a module by itself (not during kernel compile) and insert
> that module into a running kernel.

It can be done, the best example of it being done is the NVidia kernel
module. Although it seems, you want to compile a module inside a kernel
tree. I think it'll be lot complex. I dont have any hands on experience
in this, but i suggest take a look at the Makefiles of other kernel
modules available outside the kernel tree. Sorry cant give you specifics
on how to do it. 

PS: Also ALSA-driver package are nothing but kernel modules, you may
want to check thier makefiles as well.

-- 
Linux Kernel  : 2.6.15-gentoo-r7
GCC version   : 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8)
Processor     : AMD Athlon XP 2600+
RAM           : 1 GB DDR 333 SDRAM
CFLAGS USED   : -march=athlon-xp -O3 -m3dnow -msse -mmmx -pipe
                -fomit-frame-pointer -momit-leaf-frame-pointer -ftracer
	        -fno-crossjumping -falign-functions=16 -falign-loops=16
	        -falign-jumps=16 -fno-align-labels -mfpmath=387,sse
	        -maccumulate-outgoing-args
CXXFLAGS USED : $(CFLAGS) -fvisibility-inlines-hidden

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[gentoo-user] Re: modules built post kernel install (on the fly)

[Harry Putnam]

Masood Ahmed <coolmasood@gmail.com> writes:
[...]
Thanks Masood, for the pointers.. I have a question about your sig.

> --
> Linux Kernel  : 2.6.15-gentoo-r7
> GCC version   : 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8)
> Processor     : AMD Athlon XP 2600+
> RAM           : 1 GB DDR 333 SDRAM
> CFLAGS USED   : -march=athlon-xp -O3 -m3dnow -msse -mmmx -pipe
>                 -fomit-frame-pointer -momit-leaf-frame-pointer -ftracer
> 	        -fno-crossjumping -falign-functions=16 -falign-loops=16
> 	        -falign-jumps=16 -fno-align-labels -mfpmath=387,sse
> 	        -maccumulate-outgoing-args
> CXXFLAGS USED : $(CFLAGS) -fvisibility-inlines-hidden

Do you get that info from a single command or several?



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Re: [gentoo-user] Re: modules built post kernel install (on the fly)

[Masood Ahmed]

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Harry Putnam wrote:
> Masood Ahmed <coolmasood@gmail.com> writes:
> [...]
> Thanks Masood, for the pointers.. I have a question about your sig.
> 
> (....)
> 
> Do you get that info from a single command or several?
> 

The answer is several,
for kernel version i did 'uname -r'
for gcc-version i did 'gcc -v'
for processor i did 'cat /proc/cpuinfo'
for ram 'free -t'
for CFLAGS 'cat /etc/make.conf | grep CFLAGS'
for CXXFLAGS 'cat /etc/make.conf | grep CXXFLAGS'

I think this is not what you expected. I dont have enough sed and grep
knowledge to automate the process, but i'm learning it. I'd like to
write a script that would output only the required contents from the
output of the commands above. 

Got any idea's anyone?

-- 
Linux Kernel  : 2.6.15-gentoo-r7
GCC version   : 4.0.2 (Gentoo 4.0.2-r3, pie-8.7.8)
Processor     : AMD Athlon XP 2600+
RAM           : 1 GB DDR 333 SDRAM
CFLAGS USED   : -march=athlon-xp -O3 -m3dnow -msse -mmmx -pipe
                -fomit-frame-pointer -momit-leaf-frame-pointer -ftracer
	        -fno-crossjumping -falign-functions=16 -falign-loops=16
	        -falign-jumps=16 -fno-align-labels -mfpmath=387,sse
	        -maccumulate-outgoing-args
CXXFLAGS USED : $(CFLAGS) -fvisibility-inlines-hidden

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Re: [gentoo-user] Re: modules built post kernel install (on the fly)

[Boyd Stephen Smith Jr.]

On Saturday 04 March 2006 10:07, Masood Ahmed <coolmasood@gmail.com> wrote 
about 'Re: [gentoo-user]  Re: modules built post kernel install (on the 
fly)':
> Harry Putnam wrote:
> > Masood Ahmed <coolmasood@gmail.com> writes:
> > Thanks Masood, for the pointers.. I have a question about your sig.
> > Do you get that info from a single command or several?
>
> The answer is several,
> for kernel version i did 'uname -r'
> for gcc-version i did 'gcc -v'
> for processor i did 'cat /proc/cpuinfo'
> for ram 'free -t'
> for CFLAGS 'cat /etc/make.conf | grep CFLAGS'
> for CXXFLAGS 'cat /etc/make.conf | grep CXXFLAGS'
>
> I think this is not what you expected. I dont have enough sed and grep
> knowledge to automate the process, but i'm learning it. I'd like to
> write a script that would output only the required contents from the
> output of the commands above.
>
> Got any idea's anyone?

Starting from what you gave me, here's what I have:
echo -n "Linux Kernel  : "; uname -r; echo -n "GCC version   : "; gcc -v 
2>&1 | tail -n 1 | cut -d' ' -f3-; PROCS="$(grep "model 
name" /proc/cpuinfo)"; PROC_CNT=$(echo "$PROCS" | wc -l); echo -n 
"Processor     : "; if [ "$PROC_CNT" -gt 1 ]; then echo -n "${PROC_CNT}x 
"; fi; echo "$PROCS" | head -n 1 | sed -e 's/^model name[[:space:]]*: //'; 
echo -n "CFLAGS USED   : "; grep CFLAGS /etc/make.conf | grep -v 
'^[[:space:]]*#' | grep -v CXXFLAGS | sed -e 's/CFLAGS="//' -e 
's/"[[:space:]]*$//'; echo -n "CXXFLAGS USED : "; grep 
CXXFLAGS /etc/make.conf | sed -e 's/CXXFLAGS="//' -e 's/"[[:space:]]*$//'

Which, on my system, gives:
Linux Kernel  : 2.6.16-rc4-mm2
GCC version   : 3.4.5 (Gentoo 3.4.5, ssp-3.4.5-1.0, pie-8.7.9)
Processor     : 4x Dual Core AMD Opteron(tm) Processor 275
CFLAGS USED   : -O2 -pipe
CXXFLAGS USED : ${CFLAGS}

I highly doubt you got your ram line from 'free -t', on my system it gives:
             total       used       free     shared    buffers     cached
Mem:       4022704    3934496      88208          0     255028    2858408
-/+ buffers/cache:     821060    3201644
Swap:      7992312       1128    7991184
Total:    12015016    3935624    8079392

Which doesn't tell me it'd DDR or SDRAM, nor if I'm using one stick or 
many.

Modifying my script to break long CFLAGS and also accent CFLAGS that span 
multiple physical lines in make.conf is left as an excersize for the 
reader.

-- 
"If there's one thing we've established over the years,
it's that the vast majority of our users don't have the slightest
clue what's best for them in terms of package stability."
-- Gentoo Developer Ciaran McCreesh
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