The commit 2042b548 ("kbuild: unset variables in top Makefile
instead of setting 0") renamed the variable from "config-targets"
to "config-build", the comment should be consistent accordingly.
Signed-off-by: NKaiden PK Yu (余泊鎧) <KaidenPK.Yu@moxa.com>
Signed-off-by: NSZ Lin (林上智) <sz.lin@moxa.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

The dt_binding_check is added to PHONY, but it is invisible when
$(dtstree) is empty. So, it is not specified as phony for
ARCH=x86 etc.

Add it to PHONY outside the ifneq ... endif block.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NRob Herring <robh@kernel.org>

The dtbs_check should be a phony target, but currently it is not
specified so.

'make dtbs_check' works even if a file named 'dtbs_check' exists
because it depends on another phony target, scripts_dtc, but we
should not rely on it.

Add dtbs_check to PHONY.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>
Acked-by: NRob Herring <robh@kernel.org>

Complete the comments for valid values of KBUILD_VERBOSE,
specifically for KBUILD_VERBOSE=2.
Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Currently, the single-target build does not work when two
or more sub-directories are given:

  $ make fs/ kernel/ lib/
    CALL    scripts/checksyscalls.sh
    CALL    scripts/atomic/check-atomics.sh
    DESCEND  objtool
  make[2]: Nothing to be done for 'kernel/'.
  make[2]: Nothing to be done for 'fs/'.
  make[2]: Nothing to be done for 'lib/'.

Make it work properly.
Reported-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Python 2 has retired. There is no user of this variable.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Commit bc081dd6 ("kbuild: generate modules.builtin") added
infrastructure to generate modules.builtin, the list of all
builtin modules.

Basically, it works like this:

  - Kconfig generates include/config/tristate.conf, the list of
    tristate CONFIG options with a value in a capital letter.

  - scripts/Makefile.modbuiltin makes Kbuild descend into
    directories to collect the information of builtin modules.

I am not a big fan of it because Kbuild ends up with traversing
the source tree twice.

I am not sure how perfectly it should work, but this approach cannot
avoid false positives; even if the relevant CONFIG option is tristate,
some Makefiles forces obj-m to obj-y.

Some examples are:

  arch/powerpc/platforms/powermac/Makefile:
    obj-$(CONFIG_NVRAM:m=y)         += nvram.o

  net/ipv6/Makefile:
    obj-$(subst m,y,$(CONFIG_IPV6)) += inet6_hashtables.o

  net/netlabel/Makefile:
    obj-$(subst m,y,$(CONFIG_IPV6)) += netlabel_calipso.o

Nobody has complained about (or noticed) it, so it is probably fine to
have false positives in modules.builtin.

This commit simplifies the implementation. Let's exploit the fact
that every module has MODULE_LICENSE(). (modpost shows a warning if
MODULE_LICENSE is missing. If so, 0-day bot would already have blocked
such a module.)

I added MODULE_FILE to <linux/module.h>. When the code is being compiled
as builtin, it will be filled with the file path of the module, and
collected into modules.builtin.info. Then, scripts/link-vmlinux.sh
extracts the list of builtin modules out of it.

This new approach fixes the false-positives above, but adds another
type of false-positives; non-modular code may have MODULE_LICENSE()
by mistake. This is not a big deal, it is just the code is always
orphan. We can clean it up if we like. You can see cleanup examples by:

  $ git log --grep='make.* explicitly non-modular'

To sum up, this commits deletes lots of code, but still produces almost
equivalent results. Please note it does not increase the vmlinux size at
all. As you can see in include/asm-generic/vmlinux.lds.h, the .modinfo
section is discarded in the link stage.
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Introduce a new READELF variable to top-level Makefile, so the name of
readelf binary can be specified.

Before this change the name of the binary was hardcoded to
"$(CROSS_COMPILE)readelf" which might not be present for every
toolchain.

This allows to build with LLVM Object Reader by using make parameter
READELF=llvm-readelf.

Link: https://github.com/ClangBuiltLinux/linux/issues/771Signed-off-by: NDmitry Golovin <dima@golovin.in>
Reviewed-by: NNick Desaulniers <ndesaulniers@google.com>
Signed-off-by: NMasahiro Yamada <masahiroy@kernel.org>

Commit 2dffd23f ("kbuild: make single target builds much faster")
made the situation much better.

To improve it even more, apply the similar idea to the top Makefile.
Trim unrelated directories from build-dirs.

The single build code must be moved above the 'descend' target.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: NJens Axboe <axboe@kernel.dk>

Currently, some sanity checks for uapi headers are done by
scripts/headers_check.pl, which is wired up to the 'headers_check'
target in the top Makefile.

It is true compiling headers has better test coverage, but there
are still several headers excluded from the compile test. I like
to keep headers_check.pl for a while, but we can delete a lot of
code by moving the build rule to usr/include/Makefile.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

There are both positive and negative options about this feature.
At first, I thought it was a good idea, but actually Linus stated a
negative opinion (https://lkml.org/lkml/2019/9/29/227). I admit it
is ugly and annoying.

The baseline I'd like to keep is the compile-test of uapi headers.
(Otherwise, kernel developers have no way to ensure the correctness
of the exported headers.)

I will maintain a small build rule in usr/include/Makefile.
Remove the other header test functionality.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Sparse uses the same executable for all archs and uses flags
like -m64, -mbig-endian or -D__arm__ for arch-specific parameters.
But Sparse also uses value from the host machine used to build
Sparse as default value for the target machine.

This works, of course, well for native build but can create
problems when cross-compiling, like defining both '__i386__'
and '__arm__' when cross-compiling for arm on a x86-64 machine.

Fix this by explicitely telling sparse the target architecture.
Reported-by: NBen Dooks <ben.dooks@codethink.co.uk>
Signed-off-by: NLuc Van Oostenryck <luc.vanoostenryck@gmail.com>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

scripts/nsdeps is written to take care of only in-tree modules.
Perhaps, this is not a bug, but just a design. At least,
Documentation/core-api/symbol-namespaces.rst focuses on in-tree modules.

Having said that, some people already tried nsdeps for external modules.
So, it would be nice to support it.
Reported-by: NSteve French <smfrench@gmail.com>
Reported-by: NJessica Yu <jeyu@kernel.org>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: NJessica Yu <jeyu@kernel.org>
Acked-by: NJessica Yu <jeyu@kernel.org>
Reviewed-by: NMatthias Maennich <maennich@google.com>
Tested-by: NMatthias Maennich <maennich@google.com>

The modpost, with the -d option given, generates per-module .ns_deps
files.

Kbuild generates per-module .mod files to carry module information.
This is convenient because Make handles multiple jobs in parallel
when the -j option is given.

On the other hand, the modpost always runs as a single thread.
I do not see a strong reason to produce separate .ns_deps files.

This commit changes the modpost to generate just one file,
modules.nsdeps, each line of which has the following format:

  <module_name>: <list of missing namespaces>

Please note it contains *missing* namespaces instead of required ones.
So, modules.nsdeps is empty if the namespace dependency is all good.

This will work more efficiently because spatch will no longer process
already imported namespaces. I removed the '(if needed)' from the
nsdeps log since spatch is invoked only when needed.

This also solves the stale .ns_deps problem reported by Jessica Yu:

  https://lkml.org/lkml/2019/10/28/467Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: NJessica Yu <jeyu@kernel.org>
Acked-by: NJessica Yu <jeyu@kernel.org>
Reviewed-by: NMatthias Maennich <maennich@google.com>
Tested-by: NMatthias Maennich <maennich@google.com>

'make nsdeps' invokes the modpost three times at most; before linking
vmlinux, before building modules, and finally for generating .ns_deps
files. Running the modpost again and again is not efficient.

The last two can be unified. When the -d option is given, the modpost
still does the usual job, and in addition, generates .ns_deps files.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: NMatthias Maennich <maennich@google.com>
Reviewed-by: NMatthias Maennich <maennich@google.com>

There are 6 defconfigs with names longer than 24 characters, breaking
alignment in "make help".

The "winner" is "ecovec24-romimage_defconfig", counting in at 27
characters.

Extend the defconfig field size to 27 to restore alignment.
Don't use a larger value, to not encourage people to create even longer
defconfig names.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Acked-by: NHans-Christian Egtvedt <egtvedt@samfundet.no>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Some "make help" text lines extend beyond 80 characters.
Wrap them before an opening parenthesis, or before 80 characters.
Signed-off-by: NGeert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

When single-build is set, everything in $(MAKECMDGOALS) is a single
target. You can use $(MAKECMDGOALS) to list out the single targets.
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>

Commit 000ec95f ("kbuild: pkg: rename scripts/package/Makefile to
scripts/Makefile.package") missed to update this comment.

Fixes: 000ec95f ("kbuild: pkg: rename scripts/package/Makefile to scripts/Makefile.package")
Signed-off-by: NMasahiro Yamada <yamada.masahiro@socionext.com>