[ Upstream commit c473a8d0 ]

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: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

[ Upstream commit 964a596d ]

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: Masahiro Yamada <masahiroy@kernel.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

commit b1fbfcb4 upstream.

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: Masahiro Yamada <yamada.masahiro@socionext.com>
Tested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 35e046a2 upstream.

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: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 7ecaf069 upstream.

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: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit fcbb8461 upstream.

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: Masahiro Yamada <yamada.masahiro@socionext.com>
[ added to 5.4.y due to start of build warnings from backported patches
  because of this feature - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>