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>

63 files changed, 63 insertions, 0 deletions

diff --git a/tools/build/Makefile b/tools/build/Makefile
index 477f00eda591..5eb4b5ad79cb 100644
--- a/tools/build/Makefile
+++ b/tools/build/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 ifeq ($(srctree),)
 srctree := $(patsubst %/,%,$(dir $(CURDIR)))
 srctree := $(patsubst %/,%,$(dir $(srctree)))
diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
index c46b20e4ad87..cd72016c3cfa 100644
--- a/tools/build/Makefile.build
+++ b/tools/build/Makefile.build
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 ###
 # Main build makefile.
 #
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index ee2546ddf028..96982640fbf8 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 FILES=                                          \
          test-all.bin                           \
          test-backtrace.bin                     \
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index b5cfc6445771..4112702e4aed 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * test-all.c: Try to build all the main testcases at once.
  *
diff --git a/tools/build/feature/test-backtrace.c b/tools/build/feature/test-backtrace.c
index 7124aa1dc8fb..e9ddd27c69c3 100644
--- a/tools/build/feature/test-backtrace.c
+++ b/tools/build/feature/test-backtrace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <execinfo.h>
 #include <stdio.h>
 
diff --git a/tools/build/feature/test-bionic.c b/tools/build/feature/test-bionic.c
index eac24e9513eb..4bcc9776504c 100644
--- a/tools/build/feature/test-bionic.c
+++ b/tools/build/feature/test-bionic.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <android/api-level.h>
 
 int main(void)
diff --git a/tools/build/feature/test-bpf.c b/tools/build/feature/test-bpf.c
index da2172ff9662..82070eadfc07 100644
--- a/tools/build/feature/test-bpf.c
+++ b/tools/build/feature/test-bpf.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <asm/unistd.h>
 #include <linux/bpf.h>
 #include <unistd.h>
diff --git a/tools/build/feature/test-clang.cpp b/tools/build/feature/test-clang.cpp
index e23c1b1f1b91..a2b3f092d2f0 100644
--- a/tools/build/feature/test-clang.cpp
+++ b/tools/build/feature/test-clang.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include "clang/Basic/VirtualFileSystem.h"
 #include "clang/Driver/Driver.h"
 #include "clang/Frontend/TextDiagnosticPrinter.h"
diff --git a/tools/build/feature/test-compile.c b/tools/build/feature/test-compile.c
index c54e6551ae4c..9821b8271dee 100644
--- a/tools/build/feature/test-compile.c
+++ b/tools/build/feature/test-compile.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
 int main(void)
 {
diff --git a/tools/build/feature/test-cplus-demangle.c b/tools/build/feature/test-cplus-demangle.c
index 610c686e0009..2ba56474ab71 100644
--- a/tools/build/feature/test-cplus-demangle.c
+++ b/tools/build/feature/test-cplus-demangle.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 extern int printf(const char *format, ...);
 extern char *cplus_demangle(const char *, int);
 
diff --git a/tools/build/feature/test-cxx.cpp b/tools/build/feature/test-cxx.cpp
index b1dee9a31d6c..396aaedd2418 100644
--- a/tools/build/feature/test-cxx.cpp
+++ b/tools/build/feature/test-cxx.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <iostream>
 #include <memory>
 
diff --git a/tools/build/feature/test-dwarf.c b/tools/build/feature/test-dwarf.c
index 3fc1801ce4a9..8d474bd7371b 100644
--- a/tools/build/feature/test-dwarf.c
+++ b/tools/build/feature/test-dwarf.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <dwarf.h>
 #include <elfutils/libdw.h>
 #include <elfutils/version.h>
diff --git a/tools/build/feature/test-dwarf_getlocations.c b/tools/build/feature/test-dwarf_getlocations.c
index 70162699dd43..78fb4a1fa68c 100644
--- a/tools/build/feature/test-dwarf_getlocations.c
+++ b/tools/build/feature/test-dwarf_getlocations.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdlib.h>
 #include <elfutils/libdw.h>
 
diff --git a/tools/build/feature/test-get_cpuid.c b/tools/build/feature/test-get_cpuid.c
index d7a2c407130d..bb4f065f28a6 100644
--- a/tools/build/feature/test-get_cpuid.c
+++ b/tools/build/feature/test-get_cpuid.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <cpuid.h>
 
 int main(void)
diff --git a/tools/build/feature/test-glibc.c b/tools/build/feature/test-glibc.c
index 9367f7586676..9ab8e90e7b88 100644
--- a/tools/build/feature/test-glibc.c
+++ b/tools/build/feature/test-glibc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdlib.h>
 
 #if !defined(__UCLIBC__)
diff --git a/tools/build/feature/test-gtk2-infobar.c b/tools/build/feature/test-gtk2-infobar.c
index 397b4646d066..b1b716dd5733 100644
--- a/tools/build/feature/test-gtk2-infobar.c
+++ b/tools/build/feature/test-gtk2-infobar.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #pragma GCC diagnostic ignored "-Wstrict-prototypes"
 #include <gtk/gtk.h>
 #pragma GCC diagnostic error "-Wstrict-prototypes"
diff --git a/tools/build/feature/test-gtk2.c b/tools/build/feature/test-gtk2.c
index 6bd80e509439..2aaf4bfc2055 100644
--- a/tools/build/feature/test-gtk2.c
+++ b/tools/build/feature/test-gtk2.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #pragma GCC diagnostic ignored "-Wstrict-prototypes"
 #include <gtk/gtk.h>
 #pragma GCC diagnostic error "-Wstrict-prototypes"
diff --git a/tools/build/feature/test-jvmti.c b/tools/build/feature/test-jvmti.c
index 1c665f09b9d6..5cf31192f204 100644
--- a/tools/build/feature/test-jvmti.c
+++ b/tools/build/feature/test-jvmti.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <jvmti.h>
 #include <jvmticmlr.h>
 
diff --git a/tools/build/feature/test-libaudit.c b/tools/build/feature/test-libaudit.c
index afc019f08641..f5b0863fa1ec 100644
--- a/tools/build/feature/test-libaudit.c
+++ b/tools/build/feature/test-libaudit.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libaudit.h>
 
 extern int printf(const char *format, ...);
diff --git a/tools/build/feature/test-libbabeltrace.c b/tools/build/feature/test-libbabeltrace.c
index 9cf802a04885..10bb69d55694 100644
--- a/tools/build/feature/test-libbabeltrace.c
+++ b/tools/build/feature/test-libbabeltrace.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 #include <babeltrace/ctf-writer/writer.h>
 #include <babeltrace/ctf-ir/stream-class.h>
diff --git a/tools/build/feature/test-libbfd.c b/tools/build/feature/test-libbfd.c
index 24059907e990..afa46b0465cd 100644
--- a/tools/build/feature/test-libbfd.c
+++ b/tools/build/feature/test-libbfd.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <bfd.h>
 
 extern int printf(const char *format, ...);
diff --git a/tools/build/feature/test-libcrypto.c b/tools/build/feature/test-libcrypto.c
index bd79dc7f28d3..a98174e0569c 100644
--- a/tools/build/feature/test-libcrypto.c
+++ b/tools/build/feature/test-libcrypto.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <openssl/sha.h>
 #include <openssl/md5.h>
 
diff --git a/tools/build/feature/test-libdw-dwarf-unwind.c b/tools/build/feature/test-libdw-dwarf-unwind.c
index f676a3ff442a..ed03d9505609 100644
--- a/tools/build/feature/test-libdw-dwarf-unwind.c
+++ b/tools/build/feature/test-libdw-dwarf-unwind.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 #include <elfutils/libdwfl.h>
 
diff --git a/tools/build/feature/test-libelf-gelf_getnote.c b/tools/build/feature/test-libelf-gelf_getnote.c
index d78cf4d5271f..075d062fe841 100644
--- a/tools/build/feature/test-libelf-gelf_getnote.c
+++ b/tools/build/feature/test-libelf-gelf_getnote.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdlib.h>
 #include <gelf.h>
 
diff --git a/tools/build/feature/test-libelf-getphdrnum.c b/tools/build/feature/test-libelf-getphdrnum.c
index d710459306c3..96a7f8d30a59 100644
--- a/tools/build/feature/test-libelf-getphdrnum.c
+++ b/tools/build/feature/test-libelf-getphdrnum.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libelf.h>
 
 int main(void)
diff --git a/tools/build/feature/test-libelf-getshdrstrndx.c b/tools/build/feature/test-libelf-getshdrstrndx.c
index f0c3b47cce28..ae9f2fff5af0 100644
--- a/tools/build/feature/test-libelf-getshdrstrndx.c
+++ b/tools/build/feature/test-libelf-getshdrstrndx.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libelf.h>
 
 int main(void)
diff --git a/tools/build/feature/test-libelf-mmap.c b/tools/build/feature/test-libelf-mmap.c
index 564427d7ef18..2c3ef81affe2 100644
--- a/tools/build/feature/test-libelf-mmap.c
+++ b/tools/build/feature/test-libelf-mmap.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libelf.h>
 
 int main(void)
diff --git a/tools/build/feature/test-libelf.c b/tools/build/feature/test-libelf.c
index 08db322d8957..905044127d56 100644
--- a/tools/build/feature/test-libelf.c
+++ b/tools/build/feature/test-libelf.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libelf.h>
 
 int main(void)
diff --git a/tools/build/feature/test-libnuma.c b/tools/build/feature/test-libnuma.c
index 4763d9cd587d..b3aa59f8b3cb 100644
--- a/tools/build/feature/test-libnuma.c
+++ b/tools/build/feature/test-libnuma.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <numa.h>
 #include <numaif.h>
 
diff --git a/tools/build/feature/test-libperl.c b/tools/build/feature/test-libperl.c
index 8871f6a0fdb4..0415f437eb31 100644
--- a/tools/build/feature/test-libperl.c
+++ b/tools/build/feature/test-libperl.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <EXTERN.h>
 #include <perl.h>
 
diff --git a/tools/build/feature/test-libpython-version.c b/tools/build/feature/test-libpython-version.c
index facea122d812..47714b942d4d 100644
--- a/tools/build/feature/test-libpython-version.c
+++ b/tools/build/feature/test-libpython-version.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <Python.h>
 
 #if PY_VERSION_HEX >= 0x03000000
diff --git a/tools/build/feature/test-libpython.c b/tools/build/feature/test-libpython.c
index b24b28ad6324..0c1641b0d9a7 100644
--- a/tools/build/feature/test-libpython.c
+++ b/tools/build/feature/test-libpython.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <Python.h>
 
 int main(void)
diff --git a/tools/build/feature/test-libslang.c b/tools/build/feature/test-libslang.c
index 22ff22ed94d1..9cbff8d1df53 100644
--- a/tools/build/feature/test-libslang.c
+++ b/tools/build/feature/test-libslang.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <slang.h>
 
 int main(void)
diff --git a/tools/build/feature/test-libunwind-aarch64.c b/tools/build/feature/test-libunwind-aarch64.c
index fc03fb64e8c1..323803f49212 100644
--- a/tools/build/feature/test-libunwind-aarch64.c
+++ b/tools/build/feature/test-libunwind-aarch64.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind-aarch64.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind-arm.c b/tools/build/feature/test-libunwind-arm.c
index 632d95ec641f..cb378b7d6866 100644
--- a/tools/build/feature/test-libunwind-arm.c
+++ b/tools/build/feature/test-libunwind-arm.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind-arm.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind-debug-frame-aarch64.c b/tools/build/feature/test-libunwind-debug-frame-aarch64.c
index 22844673fc26..36d6646c185e 100644
--- a/tools/build/feature/test-libunwind-debug-frame-aarch64.c
+++ b/tools/build/feature/test-libunwind-debug-frame-aarch64.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind-aarch64.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind-debug-frame-arm.c b/tools/build/feature/test-libunwind-debug-frame-arm.c
index f98859684fee..8696e48e1268 100644
--- a/tools/build/feature/test-libunwind-debug-frame-arm.c
+++ b/tools/build/feature/test-libunwind-debug-frame-arm.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind-arm.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind-debug-frame.c b/tools/build/feature/test-libunwind-debug-frame.c
index 0ef8087a104a..efb55cdd8d01 100644
--- a/tools/build/feature/test-libunwind-debug-frame.c
+++ b/tools/build/feature/test-libunwind-debug-frame.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind-x86.c b/tools/build/feature/test-libunwind-x86.c
index 3561edce305e..e5e0f6c89637 100644
--- a/tools/build/feature/test-libunwind-x86.c
+++ b/tools/build/feature/test-libunwind-x86.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind-x86.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind-x86_64.c b/tools/build/feature/test-libunwind-x86_64.c
index 5add2517b2a1..62ae4db597dc 100644
--- a/tools/build/feature/test-libunwind-x86_64.c
+++ b/tools/build/feature/test-libunwind-x86_64.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind-x86_64.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-libunwind.c b/tools/build/feature/test-libunwind.c
index 43b9369bcab7..53fd26614ff0 100644
--- a/tools/build/feature/test-libunwind.c
+++ b/tools/build/feature/test-libunwind.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <libunwind.h>
 #include <stdlib.h>
 
diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
index 896d31724568..8a091625446a 100644
--- a/tools/build/feature/test-llvm-version.cpp
+++ b/tools/build/feature/test-llvm-version.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <cstdio>
 #include "llvm/Config/llvm-config.h"
 
diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
index 455a332dc8a8..88a3d1bdd9f6 100644
--- a/tools/build/feature/test-llvm.cpp
+++ b/tools/build/feature/test-llvm.cpp
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include "llvm/Support/ManagedStatic.h"
 #include "llvm/Support/raw_ostream.h"
 #define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
diff --git a/tools/build/feature/test-lzma.c b/tools/build/feature/test-lzma.c
index 95adc8ced3dd..78682bb01d57 100644
--- a/tools/build/feature/test-lzma.c
+++ b/tools/build/feature/test-lzma.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <lzma.h>
 
 int main(void)
diff --git a/tools/build/feature/test-numa_num_possible_cpus.c b/tools/build/feature/test-numa_num_possible_cpus.c
index 2606e94b0659..573d07b9c570 100644
--- a/tools/build/feature/test-numa_num_possible_cpus.c
+++ b/tools/build/feature/test-numa_num_possible_cpus.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <numa.h>
 
 int main(void)
diff --git a/tools/build/feature/test-pthread-attr-setaffinity-np.c b/tools/build/feature/test-pthread-attr-setaffinity-np.c
index fdada5e8d454..38c71131c452 100644
--- a/tools/build/feature/test-pthread-attr-setaffinity-np.c
+++ b/tools/build/feature/test-pthread-attr-setaffinity-np.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdint.h>
 #include <pthread.h>
 #include <sched.h>
diff --git a/tools/build/feature/test-sched_getcpu.c b/tools/build/feature/test-sched_getcpu.c
index 9c6b4cbffb1c..e448deb4124c 100644
--- a/tools/build/feature/test-sched_getcpu.c
+++ b/tools/build/feature/test-sched_getcpu.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #ifndef _GNU_SOURCE
 #define _GNU_SOURCE
 #endif
diff --git a/tools/build/feature/test-sdt.c b/tools/build/feature/test-sdt.c
index e4531a6e80ea..22737b0dadc8 100644
--- a/tools/build/feature/test-sdt.c
+++ b/tools/build/feature/test-sdt.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <sys/sdt.h>
 
 int main(void)
diff --git a/tools/build/feature/test-stackprotector-all.c b/tools/build/feature/test-stackprotector-all.c
index c9f398d87868..c8a57194f9f2 100644
--- a/tools/build/feature/test-stackprotector-all.c
+++ b/tools/build/feature/test-stackprotector-all.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
 
 int main(void)
diff --git a/tools/build/feature/test-sync-compare-and-swap.c b/tools/build/feature/test-sync-compare-and-swap.c
index c34d4ca4af56..1e38d1930a97 100644
--- a/tools/build/feature/test-sync-compare-and-swap.c
+++ b/tools/build/feature/test-sync-compare-and-swap.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <stdint.h>
 
 volatile uint64_t x;
diff --git a/tools/build/feature/test-timerfd.c b/tools/build/feature/test-timerfd.c
index 8c5c083b4d3c..9c72c697a9df 100644
--- a/tools/build/feature/test-timerfd.c
+++ b/tools/build/feature/test-timerfd.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * test for timerfd functions used by perf-kvm-stat-live
  */
diff --git a/tools/build/feature/test-zlib.c b/tools/build/feature/test-zlib.c
index e111fff6240e..da6c35794b93 100644
--- a/tools/build/feature/test-zlib.c
+++ b/tools/build/feature/test-zlib.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #include <zlib.h>
 
 int main(void)
diff --git a/tools/build/fixdep.c b/tools/build/fixdep.c
index 734d1547cbae..2501fea7aa3e 100644
--- a/tools/build/fixdep.c
+++ b/tools/build/fixdep.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * "Optimize" a list of dependencies as spit out by gcc -MD
  * for the build framework.
diff --git a/tools/build/tests/ex/Makefile b/tools/build/tests/ex/Makefile
index 027d6c8a58a7..fee032e06a85 100644
--- a/tools/build/tests/ex/Makefile
+++ b/tools/build/tests/ex/Makefile
@@ -1,3 +1,4 @@
+# SPDX-License-Identifier: GPL-2.0
 export srctree := $(abspath ../../../..)
 export CC      := gcc
 export LD      := ld
diff --git a/tools/build/tests/ex/a.c b/tools/build/tests/ex/a.c
index 851762798c83..66017a9f40b6 100644
--- a/tools/build/tests/ex/a.c
+++ b/tools/build/tests/ex/a.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int a(void)
 {
diff --git a/tools/build/tests/ex/arch/e.c b/tools/build/tests/ex/arch/e.c
index beaa4a1d7ba8..f6ef585b570c 100644
--- a/tools/build/tests/ex/arch/e.c
+++ b/tools/build/tests/ex/arch/e.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int e(void)
 {
diff --git a/tools/build/tests/ex/arch/f.c b/tools/build/tests/ex/arch/f.c
index 7c3e9e9da5b7..bffd9c67e9af 100644
--- a/tools/build/tests/ex/arch/f.c
+++ b/tools/build/tests/ex/arch/f.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int f(void)
 {
diff --git a/tools/build/tests/ex/b.c b/tools/build/tests/ex/b.c
index c24ff9ca9a97..2b29fb4d3c20 100644
--- a/tools/build/tests/ex/b.c
+++ b/tools/build/tests/ex/b.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int b(void)
 {
diff --git a/tools/build/tests/ex/c.c b/tools/build/tests/ex/c.c
index e216d0217499..a63b20ab83d5 100644
--- a/tools/build/tests/ex/c.c
+++ b/tools/build/tests/ex/c.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int c(void)
 {
diff --git a/tools/build/tests/ex/d.c b/tools/build/tests/ex/d.c
index 80dc0f06151b..e114e8dca0b6 100644
--- a/tools/build/tests/ex/d.c
+++ b/tools/build/tests/ex/d.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int d(void)
 {
diff --git a/tools/build/tests/ex/ex.c b/tools/build/tests/ex/ex.c
index 57de6074d252..3c02756ef912 100644
--- a/tools/build/tests/ex/ex.c
+++ b/tools/build/tests/ex/ex.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 
 int a(void);
 int b(void);
diff --git a/tools/build/tests/ex/inc.c b/tools/build/tests/ex/inc.c
index c20f1e9033a3..3636ab5bf339 100644
--- a/tools/build/tests/ex/inc.c
+++ b/tools/build/tests/ex/inc.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0
 #ifdef INCLUDE
 #include "krava.h"
 #endif
diff --git a/tools/build/tests/run.sh b/tools/build/tests/run.sh
index 44d2a0fade67..2c54e4d43546 100755
--- a/tools/build/tests/run.sh
+++ b/tools/build/tests/run.sh
@@ -1,4 +1,5 @@
 #!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
 
 function test_ex {
 	make -C ex V=1 clean > ex.out 2>&1