compiling external kernel modules (comedi.org)

compiling external kernel modules (comedi.org)

[Bernd Porr]

Hi all,

I'm trying to compile comedi on 2.6-test2. The very naive way (with 
configure) does not work (as expected). However, comedi conforms 
(mainly) to the kernel makefile convention. So I tried this:

make -C /usr/src/linux-2.6.0-test2 
SUBDIRS=/home/bp1/c/usb/2.6/comedi/comedi/ V=1

make -f scripts/Makefile.build 
obj=/home/bp1/c/usb/2.6/comedi/comedi//drivers
scripts/Makefile.build:27: kbuild: 
/home/bp1/c/usb/2.6/comedi/comedi//drivers/Makefile - Usage of 
export-objs is obsolete in 2.5. Please fix!
make -f scripts/Makefile.build 
obj=/home/bp1/c/usb/2.6/comedi/comedi//kcomedilib
scripts/Makefile.build:27: kbuild: 
/home/bp1/c/usb/2.6/comedi/comedi//kcomedilib/Makefile - Usage of 
export-objs is obsolete in 2.5. Please fix!
make -f scripts/Makefile.build obj=arch/i386/boot arch/i386/boot/bzImage
make -f scripts/Makefile.build obj=arch/i386/boot/compressed \
                                IMAGE_OFFSET=0x100000 
arch/i386/boot/compressed/
vmlinux
Kernel: arch/i386/boot/bzImage is ready
  Building modules, stage 2.
make -rR -f scripts/Makefile.modpost
  scripts/modpost vmlinux drivers/net/pcmcia/3c574_cs.o 
drivers/net/pcmcia/3c589
_cs.o drivers/net/8139cp.o drivers/net/8139too.o drivers/net/8390.o 
drivers/char
/agp/agpgart.o drivers/net/wireless/airo.o 
drivers/net/wireless/airo_cs.o driver
s/net/wireless/arlan-proc.o drivers/net/wireless/arlan.o 
drivers/net/wireless/at
mel.o drivers/net/wireless/atmel_cs.o drivers/usb/class/audio.o 
drivers/net/pcmc

Looks like as if the kernel itself has been compiled and not comedi.

In comparison: kernel 2.4.x makes it (nearly) right:

make -C /usr/src/linux SUBDIRS=/home/bp1/c/usb/2.6/comedi/comedi/

make: Entering directory `/usr/src/linux-2.4.21'
. scripts/mkversion > .tmpversion
gcc -D__KERNEL__ -I/usr/src/linux-2.4.21/include -Wall 
-Wstrict-prototypes -Wno-
trigraphs -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer 
-pipe -mpref
erred-stack-boundary=2 -march=athlon  -DUTS_MACHINE='"i386"' 
-DKBUILD_BASENAME=v
ersion -c -o init/version.o init/version.c
make CFLAGS="-D__KERNEL__ -I/usr/src/linux-2.4.21/include -Wall 
-Wstrict-prototy
pes -Wno-trigraphs -O2 -fno-strict-aliasing -fno-common 
-fomit-frame-pointer -pi
pe -mpreferred-stack-boundary=2 -march=athlon " -C  
/home/bp1/c/usb/2.6/comedi/c
omedi
make[1]: Entering directory `/home/bp1/c/usb/2.6/comedi/comedi'
gcc -D__KERNEL__ -I/usr/src/linux-2.4.21/include -Wall 
-Wstrict-prototypes -Wno-
trigraphs -O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer 
-pipe -mpref
erred-stack-boundary=2 -march=athlon  -D__KERNEL__ 
-I/usr/src/linux-2.4.21/inclu
de  -c -o comedi_fops.o comedi_fops.c
make[1]: Leaving directory `/home/bp1/c/usb/2.6/comedi/comedi'
make: Leaving directory `/usr/src/linux-2.4.21'

Is it a kernel2.6 issue or is it a comedi issue? Actually the comedi 
configuration is a hack and does not completely comply with the kernel 
makefile conventions. Probably because it has to run on either 2.x.x 
kernel. Who can help? Is the way to compile exernal modules from the 
2.4.x kernel deprecated? Is there another (more elegant) way? Would be 
nice to use as much as possible from the 2.6 stuff. Just now comdi does 
most of the stuff by a "configure" by itself. This leads to another 
problem where comedi is not able to obtain the compiler flags etc from 
the 2-6 kernel. However, this is a hack and has to be chnanged anyway.

Therefore my questions: What is the best way to compile external modules?
What has changed from 2.4 to 2.6? I noticed that .htdepend is no longer 
there and that there is no rules file.

/Bernd

-- 
http://www.cn.stir.ac.uk/~bp1/
mailto:bp1@cn.stir.ac.uk

Re: compiling external kernel modules (comedi.org)

[Sam Ravnborg]

On Sat, Aug 02, 2003 at 02:04:06AM +0100, Bernd Porr wrote:
> Hi all,
> 
> I'm trying to compile comedi on 2.6-test2. The very naive way (with 
> configure) does not work (as expected). However, comedi conforms 
> (mainly) to the kernel makefile convention. So I tried this:
> 
> make -C /usr/src/linux-2.6.0-test2 
> SUBDIRS=/home/bp1/c/usb/2.6/comedi/comedi/ V=1

When compiling modules use:
make -C /usr/src/linux-2.6.0-test2 SUBDIRS=$PWD V=1 modules
See the added "modules" target.

	Sam

Re: compiling external kernel modules (comedi.org)

[Bernd Porr]

Ok. Thanks. Now the bug is that comedi cannot find the file "Rules.make" 
which is apparently no longer there in 2.6. Is it right that the rules 
are now integrated in the corresponding makefiles?

Can you recommend me a Makefile which I can take as a template? Comedi 
uses some sort of autoconfig and I have to append then the "rules" to 
the automatically generated makefile.

Another thing: can a prevent the kernel of generating the "Stage 2"? It 
would be nice if the kernel doen't need to write to it's own directories 
if it compiles external modules. The best thing would be that one could 
compile external modules as a normal user and then only at the end 
becomes root. In my case this would be convenient as my home is a NFS 
directory which does not allow compiling as root. However the kernel 
modules at the end are stored on a root writable directory.

/Bernd

--------------------------------------------------------------------------------
removed the Rules.make includes from the comedi Makefiles:

2.4.21: only to test. Comedi cannot compile since an evil programmer has 
removed Rules.make.

snoopy:/home/bp1/c/usb/comedi/comedi# make -C /usr/src/linux 
SUBDIRS=$PWD V=1 modules
make: Entering directory `/usr/src/linux-2.4.21'
make -C  /home/bp1/c/usb/comedi/comedi CFLAGS="-D__KERNEL__ 
-I/usr/src/linux-2.4.21/include -Wall -Wstrict-prototypes -Wno-trigraphs 
-O2 -fno-strict-aliasing -fno-common -fomit-frame-pointer -pipe 
-mpreferred-stack-boundary=2 -march=athlon -DMODULE -DMODVERSIONS 
-include /usr/src/linux-2.4.21/include/linux/modversions.h" 
MAKING_MODULES=1 modules
make[1]: Entering directory `/home/bp1/c/usb/comedi/comedi'
make[1]: *** No rule to make target `modules'.  Stop.
make[1]: Leaving directory `/home/bp1/c/usb/comedi/comedi'
make: *** [_mod_/home/bp1/c/usb/comedi/comedi] Error 2
make: Leaving directory `/usr/src/linux-2.4.21'

2.6.21: Comedi compiles without error since the kernel expects the 
Makefile to trigger the make of modules which is no longer there.

snoopy:/home/bp1/c/usb/comedi/comedi# make -C /usr/src/linux-2.6.0-test2 
SUBDIRS=$PWD V=1 modules
make: Entering directory `/usr/src/linux-2.6.0-test2'
make -f scripts/Makefile.build obj=scripts
make -f scripts/Makefile.build obj=arch/i386/kernel 
arch/i386/kernel/asm-offsets.s
make[1]: `arch/i386/kernel/asm-offsets.s' is up to date.
*** Warning: Overriding SUBDIRS on the command line can cause
***          inconsistencies
mkdir -p .tmp_versions
make -f scripts/Makefile.build obj=/home/bp1/c/usb/comedi/comedi
scripts/Makefile.build:27: kbuild: 
/home/bp1/c/usb/comedi/comedi/Makefile - Usage of export-objs is 
obsolete in 2.5. Please fix!
make -f scripts/Makefile.build obj=/home/bp1/c/usb/comedi/comedi/drivers
scripts/Makefile.build:27: kbuild: 
/home/bp1/c/usb/comedi/comedi/drivers/Makefile - Usage of export-objs is 
obsolete in 2.5. Please fix!
make -f scripts/Makefile.build obj=/home/bp1/c/usb/comedi/comedi/kcomedilib
scripts/Makefile.build:27: kbuild: 
/home/bp1/c/usb/comedi/comedi/kcomedilib/Makefile - Usage of export-objs 
is obsolete in 2.5. Please fix!
  Building modules, stage 2.
make -rR -f scripts/Makefile.modpost
  scripts/modpost vmlinux drivers/net/pcmcia/3c574_cs.o 
drivers/net/pcmcia/3c589_cs.o drivers/net/8139cp.o drivers/net/8139too.o

------------------------

Sam Ravnborg wrote:

>On Sat, Aug 02, 2003 at 02:04:06AM +0100, Bernd Porr wrote:
>  
>
>>Hi all,
>>
>>I'm trying to compile comedi on 2.6-test2. The very naive way (with 
>>configure) does not work (as expected). However, comedi conforms 
>>(mainly) to the kernel makefile convention. So I tried this:
>>
>>make -C /usr/src/linux-2.6.0-test2 
>>SUBDIRS=/home/bp1/c/usb/2.6/comedi/comedi/ V=1
>>    
>>
>
>When compiling modules use:
>make -C /usr/src/linux-2.6.0-test2 SUBDIRS=$PWD V=1 modules
>See the added "modules" target.
>
>	Sam
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/
>  
>

-- 
http://www.cn.stir.ac.uk/~bp1/
mailto:bp1@cn.stir.ac.uk

Re: compiling external kernel modules (comedi.org)

[Sam Ravnborg]

On Sat, Aug 02, 2003 at 12:53:07PM +0100, Bernd Porr wrote:
> Ok. Thanks. Now the bug is that comedi cannot find the file "Rules.make" 
> which is apparently no longer there in 2.6. Is it right that the rules 
> are now integrated in the corresponding makefiles?

The way to find the Makefiles changed during the 2.5 development
cycle. Now the kbuild Makefile (the one for comedi for example) are
included from scripts/Makfile.build hereby obsoleting Rules.make.

You will NOT succeed creating a single simple makefile supporting both
2.4 and 2.6. On the other hand the Makefile are so trivial that creating
two distinct version should be acceptable?

> Can you recommend me a Makefile which I can take as a template? Comedi 
> uses some sort of autoconfig and I have to append then the "rules" to 
> the automatically generated makefile.

The most simple Makefile looks like this:

obj-m := comedi.o

No more is actually needed.
You should get rid of export-objs as well - they are also obsoleted
in 2.5/2.6.


> Another thing: can a prevent the kernel of generating the "Stage 2"? It 
> would be nice if the kernel doen't need to write to it's own directories 
> if it compiles external modules.

The right fix is to allow you to build a kernel in a directory
separate from the kernel src. This is WIP - hopefully included in 
mainline within a few weeks.

PS. Please do not cc: subscription only mailing lists.

	Sam

Re: compiling external kernel modules (comedi.org)

[Bernd Porr]

Sam,

how can I include the "legal way" includes for comedi? Just now comedi 
has set up a "linux/include" path in its directory but I think this not 
the elegant way and it also dosn't work right now.

snoopy:/home/bp1/c/usb/2.6/comedi/comedi# make -C 
/usr/src/linux-2.6.0-test2 SUBDIRS=$PWD V=1 modules
make: Entering directory `/usr/src/linux-2.6.0-test2'
make -f scripts/Makefile.build obj=scripts
make -f scripts/Makefile.build obj=arch/i386/kernel 
arch/i386/kernel/asm-offsets.s
make[1]: `arch/i386/kernel/asm-offsets.s' is up to date.
*** Warning: Overriding SUBDIRS on the command line can cause
***          inconsistencies
mkdir -p .tmp_versions
make -f scripts/Makefile.build obj=/home/bp1/c/usb/2.6/comedi/comedi
  gcc -Wp,-MD,/home/bp1/c/usb/2.6/comedi/comedi/.comedi_fops.o.d 
-D__KERNEL__ -Iinclude -Wall -Wstrict-prototypes -Wno-trigraphs -O2 
-fno-strict-aliasing -fno-common -pipe -mpreferred-stack-boundary=2 
-march=athlon -Iinclude/asm-i386/mach-default -nostdinc -iwithprefix 
include -DMODULE   -DKBUILD_BASENAME=comedi_fops 
-DKBUILD_MODNAME=comedi_fops -c -o 
/home/bp1/c/usb/2.6/comedi/comedi/comedi_fops.o 
/home/bp1/c/usb/2.6/comedi/comedi/comedi_fops.c
/home/bp1/c/usb/2.6/comedi/comedi/comedi_fops.c:42:29: 
linux/comedidev.h: No such file or directory

/Bernd
P.S.: I'm subscribed...

Sam Ravnborg wrote:

>On Sat, Aug 02, 2003 at 12:53:07PM +0100, Bernd Porr wrote:
>  
>
>>Ok. Thanks. Now the bug is that comedi cannot find the file "Rules.make" 
>>which is apparently no longer there in 2.6. Is it right that the rules 
>>are now integrated in the corresponding makefiles?
>>    
>>
>
>The way to find the Makefiles changed during the 2.5 development
>cycle. Now the kbuild Makefile (the one for comedi for example) are
>included from scripts/Makfile.build hereby obsoleting Rules.make.
>
>You will NOT succeed creating a single simple makefile supporting both
>2.4 and 2.6. On the other hand the Makefile are so trivial that creating
>two distinct version should be acceptable?
>
>  
>
>>Can you recommend me a Makefile which I can take as a template? Comedi 
>>uses some sort of autoconfig and I have to append then the "rules" to 
>>the automatically generated makefile.
>>    
>>
>
>The most simple Makefile looks like this:
>
>obj-m := comedi.o
>
>No more is actually needed.
>You should get rid of export-objs as well - they are also obsoleted
>in 2.5/2.6.
>
>
>  
>
>>Another thing: can a prevent the kernel of generating the "Stage 2"? It 
>>would be nice if the kernel doen't need to write to it's own directories 
>>if it compiles external modules.
>>    
>>
>
>The right fix is to allow you to build a kernel in a directory
>separate from the kernel src. This is WIP - hopefully included in 
>mainline within a few weeks.
>
>PS. Please do not cc: subscription only mailing lists.
>
>	Sam
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at  http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at  http://www.tux.org/lkml/
>  
>

-- 
http://www.cn.stir.ac.uk/~bp1/
mailto:bp1@cn.stir.ac.uk

Re: compiling external kernel modules (comedi.org)

[Sam Ravnborg]

On Sat, Aug 02, 2003 at 02:10:24PM +0100, Bernd Porr wrote:
> Sam,
> 
> how can I include the "legal way" includes for comedi? Just now comedi 
> has set up a "linux/include" path in its directory but I think this not 
> the elegant way and it also dosn't work right now.
I have not tried this, but specifying the include path relative to the
directory where the .c file is placed should do the trick.
So if you have:
comedi/
include/
And execute "make -C ...." within the comedi/ directory, the statement:
EXTRA_CFLAGS := -I$(obj)/../include
in the Makefile should do the trick.

> /Bernd
> P.S.: I'm subscribed...
But I'm not - getting these:

Subject: Your message to comedi awaits moderator approval

My point was not to cc: the comedi ML, since potential repliers (like me)
get these kind of replies.

	Sam

Re: compiling external kernel modules (comedi.org)

[David Woodhouse]

On Sun, 2003-08-03 at 00:05, Sam Ravnborg wrote:
> EXTRA_CFLAGS := -I$(obj)/../include
> in the Makefile should do the trick.

Be careful -- in the case where you're building a newer driver than one
which is already in the kernel, you may need to ensure your own include
directory supersedes the kernel's. In that case 'CC=$(CROSS_COMPILE)gcc
-I$(obj)/../include' may be useful.

An example which is currently working for 2.4 and 2.6 kernels, and which
used to work for 2.2 too until quite recently, is at
http://cvs.infradead.org/cgi-bin/cvsweb.cgi/mtd/drivers/mtd/

Some people seem to think that the 'SUBDIRS=' trick is a new thing for
2.6. It's not -- it's worked for ever, and was _always_ the only
reliable way of building modules to match the kernel.


-- 
dwmw2