kbuild: simplify dtbs_install by reading the list of compiled DTBs

Retrieve the list of *.dtb(o) files from arch/*/boot/dts/dtbs-list
instead of traversing the directory tree again.

Please note that 'make dtbs_install' installs *.dtb(o) files directly
added to dtb-y because scripts/Makefile.dtbinst installs $(dtb-y)
without expanding the -dtbs suffix.

This commit preserves this behavior.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: Support flat DTBs install

In preparation to move Arm .dts files into sub-directories grouped
by vendor/family, the current flat tree of DTBs generated by
dtbs_install needs to be maintained. Moving the installed DTBs to
sub-directories would break various consumers using 'make dtbs_install'.

This is a NOP until sub-directories are introduced.

Signed-off-by: Rob Herring <robh@kernel.org>

kbuild: add kbuild-file macro

While building, installing, cleaning, Kbuild visits sub-directories
and includes 'Kbuild' or 'Makefile' that exists there.

Add 'kbuild-file' macro, and reuse it from scripts/Makefie.*

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
Reviewed-by: Alexander Lobakin <alobakin@pm.me>
Tested-by: Alexander Lobakin <alobakin@pm.me>

kbuild: prefix $(srctree)/ to some included Makefiles

VPATH is used in Kbuild to make pattern rules search for prerequisites
in both $(objtree) and $(srctree). Some of *.c, *.S files are not real
sources, but generated by tools such as flex, bison, perl.

In contrast, I doubt the benefit of --include-dir=$(abs_srctree) because
it is always clear which Makefiles are real sources, and which are not.

So, my hope is to add $(srctree)/ prefix to all check-in Makefiles,
then remove --include-dir=$(abs_srctree) flag in the future.

I am touching only some Kbuild core parts for now. Treewide fixes will
be needed to achieve this goal.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: Add support to build overlays (%.dtbo)

Add support for building DT overlays (%.dtbo). The overlay's source file
will have the usual extension, i.e. .dts, though the blob will have
.dtbo extension to distinguish it from normal blobs.

Acked-by: Masahiro Yamada <masahiroy@kernel.org>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/434ba2467dd0cd011565625aeb3450650afe0aae.1611904394.git.viresh.kumar@linaro.org

kbuild: refactor Makefile.dtbinst more

Refactor Makefile.dtbinst so it looks similar to other Makefiles.

*.dtb should not be a phony target. Copy files based on the timestamps.
Print installed dtb paths instead of in-kernel dtb paths.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: compute the dtbs_install destination more simply

The 'dtbinst_root' is used to remember the root of the in-kernel dts
directory (i.e. arch/*/boot/dts), but it looks clumsy.

I prefer using two variables 'obj' and 'dst' to track the in-kernel
directory and the install destination, respectively.

Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>

kbuild: handle dtb-y and CONFIG_OF_ALL_DTBS natively in Makefile.lib

If CONFIG_OF_ALL_DTBS is enabled, "make ARCH=arm64 dtbs" compiles each
DTB twice; one from arch/arm64/boot/dts/*/Makefile and the other from
the dtb-$(CONFIG_OF_ALL_DTBS) line in arch/arm64/boot/dts/Makefile.
It could be a race problem when building DTBS in parallel.

Another minor issue is CONFIG_OF_ALL_DTBS covers only *.dts in vendor
sub-directories, so this broke when Broadcom added one more hierarchy
in arch/arm64/boot/dts/broadcom/<soc>/.

One idea to fix the issues in a clean way is to move DTB handling
to Kbuild core scripts. Makefile.dtbinst already recognizes dtb-y
natively, so it should not hurt to do so.

Add $(dtb-y) to extra-y, and $(dtb-) as well if CONFIG_OF_ALL_DTBS is
enabled. All clutter things in Makefiles go away.

As a bonus clean-up, I also removed dts-dirs. Just use subdir-y
directly to traverse sub-directories.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
[robh: corrected BUILTIN_DTB to CONFIG_BUILTIN_DTB]
Signed-off-by: Rob Herring <robh@kernel.org>

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

Many source files in the tree are missing licensing information, which
makes it harder for compliance tools to determine the correct license.

By default all files without license information are under the default
license of the kernel, which is GPL version 2.

Update the files which contain no license information with the 'GPL-2.0'
SPDX license identifier. The SPDX identifier is a legally binding
shorthand, which can be used instead of the full boiler plate text.

This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne.

How this work was done:

Patches were generated and checked against linux-4.14-rc6 for a subset of
the use cases:
- file had no licensing information it it.
- file was a */uapi/* one with no licensing information in it,
- file was a */uapi/* one with existing licensing information,

Further patches will be generated in subsequent months to fix up cases
where non-standard license headers were used, and references to license
had to be inferred by heuristics based on keywords.

The analysis to determine which SPDX License Identifier to be applied to
a file was done in a spreadsheet of side by side results from of the
output of two independent scanners (ScanCode & Windriver) producing SPDX
tag:value files created by Philippe Ombredanne. Philippe prepared the
base worksheet, and did an initial spot review of a few 1000 files.

The 4.13 kernel was the starting point of the analysis with 60,537 files
assessed. Kate Stewart did a file by file comparison of the scanner
results in the spreadsheet to determine which SPDX license identifier(s)
to be applied to the file. She confirmed any determination that was not
immediately clear with lawyers working with the Linux Foundation.

Criteria used to select files for SPDX license identifier tagging was:
- Files considered eligible had to be source code files.
- Make and config files were included as candidates if they contained >5
lines of source
- File already had some variant of a license header in it (even if <5
lines).

All documentation files were explicitly excluded.

The following heuristics were used to determine which SPDX license
identifiers to apply.

- when both scanners couldn't find any license traces, file was
considered to have no license information in it, and the top level
COPYING file license applied.

For non */uapi/* files that summary was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 11139

and resulted in the first patch in this series.

If that file was a */uapi/* path one, it was "GPL-2.0 WITH
Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was:

SPDX license identifier # files
---------------------------------------------------|-------
GPL-2.0 WITH Linux-syscall-note 930

and resulted in the second patch in this series.

- if a file had some form of licensing information in it, and was one
of the */uapi/* ones, it was denoted with the Linux-syscall-note if
any GPL family license was found in the file or had no licensing in
it (per prior point). Results summary:

SPDX license identifier # files
---------------------------------------------------|------
GPL-2.0 WITH Linux-syscall-note 270
GPL-2.0+ WITH Linux-syscall-note 169
((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21
((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17
LGPL-2.1+ WITH Linux-syscall-note 15
GPL-1.0+ WITH Linux-syscall-note 14
((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5
LGPL-2.0+ WITH Linux-syscall-note 4
LGPL-2.1 WITH Linux-syscall-note 3
((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3
((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1

and that resulted in the third patch in this series.

- when the two scanners agreed on the detected license(s), that became
the concluded license(s).

- when there was disagreement between the two scanners (one detected a
license but the other didn't, or they both detected different
licenses) a manual inspection of the file occurred.

- In most cases a manual inspection of the information in the file
resulted in a clear resolution of the license that should apply (and
which scanner probably needed to revisit its heuristics).

- When it was not immediately clear, the license identifier was
confirmed with lawyers working with the Linux Foundation.

- If there was any question as to the appropriate license identifier,
the file was flagged for further research and to be revisited later
in time.

In total, over 70 hours of logged manual review was done on the
spreadsheet to determine the SPDX license identifiers to apply to the
source files by Kate, Philippe, Thomas and, in some cases, confirmation
by lawyers working with the Linux Foundation.

Kate also obtained a third independent scan of the 4.13 code base from
FOSSology, and compared selected files where the other two scanners
disagreed against that SPDX file, to see if there was new insights. The
Windriver scanner is based on an older version of FOSSology in part, so
they are related.

Thomas did random spot checks in about 500 files from the spreadsheets
for the uapi headers and agreed with SPDX license identifier in the
files he inspected. For the non-uapi files Thomas did random spot checks
in about 15000 files.

In initial set of patches against 4.14-rc6, 3 files were found to have
copy/paste license identifier errors, and have been fixed to reflect the
correct identifier.

Additionally Philippe spent 10 hours this week doing a detailed manual
inspection and review of the 12,461 patched files from the initial patch
version early this week with:
- a full scancode scan run, collecting the matched texts, detected
license ids and scores
- reviewing anything where there was a license detected (about 500+
files) to ensure that the applied SPDX license was correct
- reviewing anything where there was no detection but the patch license
was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied
SPDX license was correct

This produced a worksheet with 20 files needing minor correction. This
worksheet was then exported into 3 different .csv files for the
different types of files to be modified.

These .csv files were then reviewed by Greg. Thomas wrote a script to
parse the csv files and add the proper SPDX tag to the file, in the
format that the file expected. This script was further refined by Greg
based on the output to detect more types of files automatically and to
distinguish between header and source .c files (which need different
comment types.) Finally Greg ran the script using the .csv files to
generate the patches.

Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

kbuild: Do not use hyphen in exported variable name

This definition in Makefile.dtbinst:

export dtbinst-root ?= $(obj)

should define and export dtbinst-root when handling the root dts
directory, and do nothing in the subdirectories. However some shells,
including dash, will not pass through environment variables whose name
includes a hyphen. Usually GNU make does not use a shell to recurse,
but if e.g. $(srctree) contains '~' it will use a shell here.

Rename the variable to dtbinst_root.

References: https://bugs.debian.org/833561
Fixes: 323a028d39cdi ("dts, kbuild: Implement support for dtb vendor subdirs")
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

kbuild: dtbinst: remove unnecessary __dtbs_install_prep target

Since commit 5399eb9b3908 ("dtbsinstall: don't move target directory
out of the way"), the target __dtbs_install_prep is invoked just for
creating the install directory, but all the necessary directories
are automatically created by:
cmd_dtb_install = mkdir -p $(2); cp $< $(2)

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>

dtbsinstall: don't move target directory out of the way

No other kernel installation target moves the target directory out of
the way, even deleting an old version of it. These are destructive
operations, ones which the kernel build system should not be making.

This behaviour prevents being able to do:

make install INSTALL_PATH=/some/path/boot
make dtbs_install INSTALL_DTBS_PATH=/some/path/boot

As it causes the boot directory containing the kernel installed in
step 1 to be moved to /some/path/boot.old. Things get even more fun
if you do:

make install dtbs_install INSTALL_PATH=/some/path/boot INSTALL_DTBS_PATH=/some/path/boot

The kernel gets installed into /some/path/boot, then the directory gets
renamed to /some/path/boot.old, and a new directory created to hold the
dtbs. Even more fun if you supply -j2 when we end up with races in
make.

Remove this behaviour.

If this behaviour is required at installation time, this should be
done by the installation external to the kernel makefiles, just like
it would be done for 'make modules_install'.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Acked-by: Jason Cooper <jason@lakedaemon.net>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Michal Marek <mmarek@suse.com>

kbuild: include $(src)/Makefile rather than $(obj)/Makefile

This commit actually has no impact because $(src) and $(obj) point
to the same path, but $(src)/Makefile looks better when we include
source files.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

kbuild: use relative path to include Makefile

The "MAKEFLAGS += --include-dir=$(srctree)" line in the top Makefile
allows us to do this.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>

dts, kbuild: Implement support for dtb vendor subdirs

This patch adds support of vendor sub directories for dtb files.
Subdirectories can be specified in $(dts-dirs). Kbuild traverses over
all directories while building and installing dtb files. The directory
tree is also reflected in the install path.

Tested-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Robert Richter <rrichter@cavium.com>

dts, kbuild: Factor out dtbs install rules to Makefile.dtbinst

Move dtbs install rules to Makefile.dtbinst. This change is needed to
implement support for dts vendor subdirs. The change makes Makefiles
easier and smaller as no longer the dtbs_install rule needs to be
defined. Another advantage is that install goals are not encoded in
targets anymore (%.dtb_dtbinst_).

Signed-off-by: Robert Richter <rrichter@cavium.com>