Re: [Kbuild] How to clean a particular directory ?

[Paul Mundt <lethal@linux-sh.org>]

On Thu, Jan 31, 2008 at 05:48:51PM +0900, Paul Mundt wrote:
> On Thu, Jan 31, 2008 at 09:38:10AM +0100, Francis Moreau wrote:
> > I'd like to clean a particular directory in the kernel tree.
> > 
> > I tried several things such as:
> > 
> > $ make drivers/char clean
> > $ make -f scripts/Makefile.clean obj=drivers/char
> > 
> > But it doesn't work.
> > 
> > Could anybody give me  a hint ?
> 
> make SUBDIRS=drivers/char clean
> 
> should do the trick. Kbuild might have a magic incantation for it these
> days, but that's the way it used to work, and still seems to.

Makefile says:

# Use make M=dir to specify directory of external module to build
# Old syntax make ... SUBDIRS=$PWD is still supported
# Setting the environment variable KBUILD_EXTMOD take precedence
ifdef SUBDIRS
  KBUILD_EXTMOD ?= $(SUBDIRS)
endif
ifdef M
  ifeq ("$(origin M)", "command line")
    KBUILD_EXTMOD := $(M)
  endif
endif

so M= is apparently the newfangled (and undocumented) way of doing this.