[PATCH 00/23] kbuild: support building external modules in a separate build directory

[Masahiro Yamada <masahiroy@kernel.org>]

There has been a long-standing request to support building external
modules in a separate build directory.

The first half is cleanups of documents and Makefiles.

The last part adds KBUILD_EXTMOD_OUTPUT (MO=).
This is too big changes, and too late for the current MW.
(I did not test kselftest at all.)
I hope people test this and may uncover some issues.



Masahiro Yamada (23):
  kbuild: doc: update the description about Kbuild/Makefile split
  kbuild: doc: remove description about grepping CONFIG options
  kbuild: doc: remove outdated description of the limitation on -I usage
  kbuild: doc: remove the description about shipped files
  kbuild: doc: describe the -C option precisely for external module
    builds
  kbuild: doc: replace "gcc" in external module description
  kbuild: remove unnecessary prune of rust/alloc for rustfmt
  kbuild: simplify find command for rustfmt
  speakup: use SPKDIR=$(src) to specify the source directory
  kbuild: refactor the check for missing config files
  kbuild: check the presence of include/generated/rustc_cfg
  scripts/nsdeps: use VPATH as src_prefix
  kbuild: replace two $(abs_objtree) with $(CURDIR) in top Makefile
  kbuild: add $(objtree)/ prefix to some in-kernel build artifacts
  kbuild: rename abs_objtree to abs_output
  kbuild: use 'output' variable to create the output directory
  kbuild: build external modules in their directory
  kbuild: remove extmod_prefix, MODORDER, MODULES_NSDEPS variables
  kbuild: support building external modules in a separate build
    directory
  kbuild: support -fmacro-prefix-map for external modules
  kbuild: use absolute path in the generated wrapper Makefile
  kbuild: make wrapper Makefile more convenient for external modules
  kbuild: allow to start building external module in any directory

 Documentation/dev-tools/coccinelle.rst |  19 +--
 Documentation/kbuild/kbuild.rst        |  11 ++
 Documentation/kbuild/modules.rst       | 104 ++++----------
 Makefile                               | 184 ++++++++++++++++---------
 drivers/accessibility/speakup/Makefile |   4 +-
 rust/Makefile                          |   4 +-
 scripts/Kbuild.include                 |   2 +-
 scripts/Makefile.build                 |   4 +-
 scripts/Makefile.compiler              |   2 +-
 scripts/Makefile.modfinal              |  16 +--
 scripts/Makefile.modinst               |   4 +-
 scripts/Makefile.modpost               |  24 ++--
 scripts/coccicheck                     |   6 +-
 scripts/depmod.sh                      |   4 +-
 scripts/nsdeps                         |   6 +-
 scripts/package/install-extmod-build   |   7 +
 16 files changed, 209 insertions(+), 192 deletions(-)

-- 
2.43.0