Re: buffer cache

[Jan Hudec <bulb@ucw.cz>]

On Sun, Sep 14, 2003 at 11:37:22 +0100, David Woodhouse wrote:
> Please don't drop me from the recipients when replying; it's very rude.
> 
> On Sun, 2003-09-14 at 12:03 +0200, Jan Hudec wrote:
> > > Probably as a result of hacking up his own broken makefiles instead of 
> > > 	make -C $KERNELDIR SUBDIRS=`pwd` modules
> > 
> > Well, I wrote a module to compile off-tree. The correct command to link
> > a module is:
> > ld -r -o <modname>.o <objects...>
> 
> No, that's not always correct. It's completely wrong for 2.6, of course
> -- and even for 2.4, if building modules for a 64-bit kernel, you may
> find your userspace is 32-bit by default and you need something like
> -melf64_sparc on the linker command line. The kernel makefiles get this
> right. Use them.
> 
> The kernel is also free to screw with its own internal ABI all it likes
> -- with cflags affecting global register usage, etc. You must do as it
> does in the kernel you happen to be building -- which basically means

Which I basicaly do becasue I ask kernel to give me the flags it uses.

> you must use the kernel build system.

That's what the script target is for.

> The correct way to build modules out of the kernel tree is to use the
> kernel makefiles and override SUBDIRS to point at your own directory;
> it's been that way since 2.0 if not earlier.

Well... I can't imagine compiling a project with various objects spead
all over the place (I have a driver, that has various pieces common with
various other programs) using the kernel build system. So it reduces back
to geting right flags from it.

-------------------------------------------------------------------------------
						 Jan 'Bulb' Hudec <bulb@ucw.cz>