Compile external module with seperate source and object directories

Re: Compile external module with seperate source and object directories

On Wed, Jan 12, 2005 at 10:39:56PM -0000, Ross C Mcilroy wrote:
> 
> The dependancies between these files and the created object files were handled using the
> VPATH variable in the previous makefile, however this doesn't seem to work with the
> 2.6 kernel (I assume because VPATH is already defined in the root kernel makefile).
> The linux kernel module make therefore doesn't find the required source files.
> Is this possible with the new external module build process?

kbuild does not support storing output files in a separate directory for
external modules so the answer is no.

The request has been few - and the solution has not been obvoius. So
there is niether plan to add this to kbuild. But if someone can come
with a nice minimal patch it will be considered.

	Sam

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changing local version requires full rebuild

Hi!
Is it just me, or does changing the local version always require
a full kernel rebuild?

If so, I'd like to fix it, since I like copying
my kernel source with --preserve and changing the
local version, then going back to the old version in case of
a crash.
Its important to change the local version to force 
make install and make modules_install to put things in a separate
directory.

Any ideas on why is that and whether its possible to fix it?

mst

Re: changing local version requires full rebuild

On Sun, Jan 16, 2005 at 05:22:42PM +0200, Michael S. Tsirkin wrote:
> Hi!
> Is it just me, or does changing the local version always require
> a full kernel rebuild?
> 
> If so, I'd like to fix it, since I like copying
> my kernel source with --preserve and changing the
> local version, then going back to the old version in case of
> a crash.
> Its important to change the local version to force 
> make install and make modules_install to put things in a separate
> directory.

Just tried it out here.
After cp -Ra only a limited part of the kernel rebuilds.
o oiu.c in ieee directory - because it dependson the shell script
o A number of drivers that include version.h
	- This should be changed so local version does not affect
	  the reast of version.h.
o Other stuff that is always build if kernel has changed

Do you use "echo -mylocalver > localversion" to change the local version?

	Sam

Re: changing local version requires full rebuild

Hello!
Quoting r. Sam Ravnborg (sam <at> ravnborg.org) "Re: changing local version requires full rebuild":
> On Sun, Jan 16, 2005 at 05:22:42PM +0200, Michael S. Tsirkin wrote:
> > Hi!
> > Is it just me, or does changing the local version always require
> > a full kernel rebuild?
> > 
> > If so, I'd like to fix it, since I like copying
> > my kernel source with --preserve and changing the
> > local version, then going back to the old version in case of
> > a crash.
> > Its important to change the local version to force 
> > make install and make modules_install to put things in a separate
> > directory.
> 
> Just tried it out here.
> After cp -Ra only a limited part of the kernel rebuilds.
> o oiu.c in ieee directory - because it dependson the shell script
> o A number of drivers that include version.h
> 	- This should be changed so local version does not affect
> 	  the reast of version.h.
> o Other stuff that is always build if kernel has changed
> 
> Do you use "echo -mylocalver > localversion" to change the local version?
> 
> 	Sam

No, I do makemenuconfig to edit the version. Is that right?

mst

Re: changing local version requires full rebuild

Hello!
Quoting r. Sam Ravnborg (sam <at> ravnborg.org) "Re: changing local version requires full rebuild":
> On Sun, Jan 16, 2005 at 05:22:42PM +0200, Michael S. Tsirkin wrote:
> > Hi!
> > Is it just me, or does changing the local version always require
> > a full kernel rebuild?
> > 
> > If so, I'd like to fix it, since I like copying
> > my kernel source with --preserve and changing the
> > local version, then going back to the old version in case of
> > a crash.
> > Its important to change the local version to force 
> > make install and make modules_install to put things in a separate
> > directory.
> 
> Just tried it out here.
> After cp -Ra only a limited part of the kernel rebuilds.
> o oiu.c in ieee directory - because it dependson the shell script
> o A number of drivers that include version.h
> 	- This should be changed so local version does not affect
> 	  the reast of version.h.
> o Other stuff that is always build if kernel has changed
> 
> Do you use "echo -mylocalver > localversion" to change the local version?
> 
> 	Sam

Just tried this with the same effect.

Could it be your version was already -mylocalver?

Please note that you have to actually *change* the local
version, otherwise almost nothing is recompiled.
Just a touch does nothing.

Actually, the directory kernel/ is not recompiled (so the subject is a
bit misleading) , but a huge number of files in drivers, filesystems, sound,
lib and net directory - are.

MST

Re: changing local version requires full rebuild

 > 
> > Do you use "echo -mylocalver > localversion" to change the local version?
> > 
> > 	Sam
> 
> No, I do makemenuconfig to edit the version. Is that right?

That is fine too.
When building - do you use separate output dir?

	Sam

Re: changing local version requires full rebuild

Hello!
Quoting r. Sam Ravnborg (sam <at> ravnborg.org) "Re: changing local version requires full rebuild":
>  > 
> > > Do you use "echo -mylocalver > localversion" to change the local version?
> > > 
> > > 	Sam
> > 
> > No, I do makemenuconfig to edit the version. Is that right?
> 
> That is fine too.
> When building - do you use separate output dir?
> 
> 	Sam

nope, just make

Re: changing local version requires full rebuild

Hello!
Quoting r. Sam Ravnborg (sam <at> ravnborg.org) "Re: changing local version requires full rebuild":
> On Sun, Jan 16, 2005 at 05:22:42PM +0200, Michael S. Tsirkin wrote:
> > Hi!
> > Is it just me, or does changing the local version always require
> > a full kernel rebuild?
> > 
> > If so, I'd like to fix it, since I like copying
> > my kernel source with --preserve and changing the
> > local version, then going back to the old version in case of
> > a crash.
> > Its important to change the local version to force 
> > make install and make modules_install to put things in a separate
> > directory.
> 
> Just tried it out here.
> After cp -Ra only a limited part of the kernel rebuilds.
> o oiu.c in ieee directory - because it dependson the shell script
> o A number of drivers that include version.h
> 	- This should be changed so local version does not affect
> 	  the reast of version.h.

We now have:
swlab155:/usr/src/linux-2.6.10-gold # grep version.h -rI . | wc -l
2143
swlab155:/usr/src/linux-2.6.10-gold # grep UTS_RELEASE -rIi .| wc -l
47

So it appears that its much simpler to change all users of
UTS_RELEASE to use some other file, say local_version.h,
and have localversion not affect version.h

Opinions?

mst

Re: changing local version requires full rebuild

Hello!
Quoting r. Sam Ravnborg (sam <at> ravnborg.org) "Re: changing local version requires full rebuild":
>  > 
> > > Do you use "echo -mylocalver > localversion" to change the local version?
> > > 
> > > 	Sam
> > 
> > No, I do makemenuconfig to edit the version. Is that right?
> 
> That is fine too.
> When building - do you use separate output dir?
> 
> 	Sam

First, by design any module includes the full
kernel release name as part of the VERMAGIC_STRING.
So at least one file will have to be rebuilt for each module,
and all modules have to be relinked, if localversion changes.

MST