Re: External compilation

[Kai Germaschewski]

On Mon, 10 Jun 2002, John Levon wrote:

> Doesn't work for 2.2. Hopefully I will be able to specify M_OBJS in
> addition.

I think later 2.2 support obj-[ym], though I maybe wrong. It won't hurt to
specify M_OBJS additionally.

> Also, you don't specify O_TARGET ?
> 
> Given :
> 
> TOPDIR=/usr/src/linux
> THISDIR=/tmp/mod
>  
> O_TARGET=lartmod.o
> obj-m := lart.o blah.o
>  
> include $(TOPDIR)/Rules.make
>  
> all:
>         (cd $(TOPDIR) && $(MAKE) SUBDIRS=/tmp/mod modules)

My example was for a single source module. If you have multiple sources,
you can either

	O_TARGET := lartmod.o
	obj-y	 := lart.o blah.o
	obj-m    := $(O_TARGET)

or

	obj-m    := lartmod.o

	lartmod-objs := lart.o blah.o

where the later in 2.4 additionally needs

	list-multi := lartmod.o

and a link rule like

	lartmod.o: $(lartmod-objs)
        	$(LD) -r -o $@ $(lartmod-objs)

> a) default target for Rules.make doesn't do anything useful

The default target (at least in < current 2.5) only builds built-in code.

> b) lartmod.o is never made (how could I convince it to ?)

See first example above.

> c) is this going to work OK for modversions...

Yup.

> d) the above seems to disallow a lart.c forming only part of a final lart.o target

If you only have one source, see my first mail.

> e) there seems something is going horribly wrong :
> 
> moz mod 317 make all
> make: execvp: /usr/src/linux/scripts/pathdown.sh: Permission denied
> ˆ¶@ˆ¶@re/locale/en_US/LC_MESSAGES/make.mo(cd /usr/src/linux && make SUBDIRS=/tmp/mod modules)
> make[1]: Entering directory `/usr/src/linux-2.4.0'

That I suppose is due to the fact that during the "make all" 
$(CONFIG_SHELL) is not set, thus the

	MOD_DESTDIR := $(shell $(CONFIG_SHELL) $(TOPDIR)/scripts/pathdown.sh)

in Rules.make fails. Try doing the "cd $(TOPDIR) && ..." by hand, it 
should work then.

--Kai