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>

30 files changed, 30 insertions, 0 deletions

diff --git a/tools/include/linux/atomic.h b/tools/include/linux/atomic.h
index 9f21fc2b092b..00a6c4ca562b 100644
--- a/tools/include/linux/atomic.h
+++ b/tools/include/linux/atomic.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __TOOLS_LINUX_ATOMIC_H
 #define __TOOLS_LINUX_ATOMIC_H
 
diff --git a/tools/include/linux/bitmap.h b/tools/include/linux/bitmap.h
index e8b9f518e36b..ca160270fdfa 100644
--- a/tools/include/linux/bitmap.h
+++ b/tools/include/linux/bitmap.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _PERF_BITOPS_H
 #define _PERF_BITOPS_H
 
diff --git a/tools/include/linux/bitops.h b/tools/include/linux/bitops.h
index 969db1981868..acc704bd3998 100644
--- a/tools/include/linux/bitops.h
+++ b/tools/include/linux/bitops.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_BITOPS_H_
 #define _TOOLS_LINUX_BITOPS_H_
 
diff --git a/tools/include/linux/bug.h b/tools/include/linux/bug.h
index 8e4a4f49135d..85f80258a15f 100644
--- a/tools/include/linux/bug.h
+++ b/tools/include/linux/bug.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_PERF_LINUX_BUG_H
 #define _TOOLS_PERF_LINUX_BUG_H
 
diff --git a/tools/include/linux/compiler-gcc.h b/tools/include/linux/compiler-gcc.h
index 3723b9f8f964..a3a4427441bf 100644
--- a/tools/include/linux/compiler-gcc.h
+++ b/tools/include/linux/compiler-gcc.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_COMPILER_H_
 #error "Please don't include <linux/compiler-gcc.h> directly, include <linux/compiler.h> instead."
 #endif
diff --git a/tools/include/linux/compiler.h b/tools/include/linux/compiler.h
index d7a5604c38d7..07fd03c74a77 100644
--- a/tools/include/linux/compiler.h
+++ b/tools/include/linux/compiler.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_COMPILER_H_
 #define _TOOLS_LINUX_COMPILER_H_
 
diff --git a/tools/include/linux/debug_locks.h b/tools/include/linux/debug_locks.h
index 61cc7f501168..72d595ce764a 100644
--- a/tools/include/linux/debug_locks.h
+++ b/tools/include/linux/debug_locks.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_DEBUG_LOCKS_H_
 #define _LIBLOCKDEP_DEBUG_LOCKS_H_
 
diff --git a/tools/include/linux/err.h b/tools/include/linux/err.h
index abf0478a8fb2..7a8b61ad44cb 100644
--- a/tools/include/linux/err.h
+++ b/tools/include/linux/err.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __TOOLS_LINUX_ERR_H
 #define __TOOLS_LINUX_ERR_H
 
diff --git a/tools/include/linux/filter.h b/tools/include/linux/filter.h
index 4ce25d43e8e3..c5e512da8d8a 100644
--- a/tools/include/linux/filter.h
+++ b/tools/include/linux/filter.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Linux Socket Filter Data Structures
  */
diff --git a/tools/include/linux/hardirq.h b/tools/include/linux/hardirq.h
index c8f3f8f58729..b25580b6a9be 100644
--- a/tools/include/linux/hardirq.h
+++ b/tools/include/linux/hardirq.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LINUX_HARDIRQ_H_
 #define _LIBLOCKDEP_LINUX_HARDIRQ_H_
 
diff --git a/tools/include/linux/hash.h b/tools/include/linux/hash.h
index ad6fa21d977b..2c4183bbc504 100644
--- a/tools/include/linux/hash.h
+++ b/tools/include/linux/hash.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_HASH_H
 #define _LINUX_HASH_H
 /* Fast hashing routine for ints,  longs and pointers.
diff --git a/tools/include/linux/hashtable.h b/tools/include/linux/hashtable.h
index 251eabf2a05e..434dd5ac6d71 100644
--- a/tools/include/linux/hashtable.h
+++ b/tools/include/linux/hashtable.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 /*
  * Statically sized hash table implementation
  * (C) 2012  Sasha Levin <levinsasha928@gmail.com>
diff --git a/tools/include/linux/irqflags.h b/tools/include/linux/irqflags.h
index df77669cfe1c..e734da3e5b33 100644
--- a/tools/include/linux/irqflags.h
+++ b/tools/include/linux/irqflags.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LINUX_TRACE_IRQFLAGS_H_
 #define _LIBLOCKDEP_LINUX_TRACE_IRQFLAGS_H_
 
diff --git a/tools/include/linux/kallsyms.h b/tools/include/linux/kallsyms.h
index 582cc1e5f3a4..89ca6fe257cc 100644
--- a/tools/include/linux/kallsyms.h
+++ b/tools/include/linux/kallsyms.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LINUX_KALLSYMS_H_
 #define _LIBLOCKDEP_LINUX_KALLSYMS_H_
 
diff --git a/tools/include/linux/kern_levels.h b/tools/include/linux/kern_levels.h
index 3b9bade28698..778ecb984480 100644
--- a/tools/include/linux/kern_levels.h
+++ b/tools/include/linux/kern_levels.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __KERN_LEVELS_H__
 #define __KERN_LEVELS_H__
 
diff --git a/tools/include/linux/kernel.h b/tools/include/linux/kernel.h
index 77d2e94ca5df..0ad884452c5c 100644
--- a/tools/include/linux/kernel.h
+++ b/tools/include/linux/kernel.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __TOOLS_LINUX_KERNEL_H
 #define __TOOLS_LINUX_KERNEL_H
 
diff --git a/tools/include/linux/kmemcheck.h b/tools/include/linux/kmemcheck.h
index 94d598bc6abe..2bccd2c7b897 100644
--- a/tools/include/linux/kmemcheck.h
+++ b/tools/include/linux/kmemcheck.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LINUX_KMEMCHECK_H_
 #define _LIBLOCKDEP_LINUX_KMEMCHECK_H_
 
diff --git a/tools/include/linux/list.h b/tools/include/linux/list.h
index 1da423820ad4..b2fc48d5478c 100644
--- a/tools/include/linux/list.h
+++ b/tools/include/linux/list.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __TOOLS_LINUX_LIST_H
 #define __TOOLS_LINUX_LIST_H
 
diff --git a/tools/include/linux/lockdep.h b/tools/include/linux/lockdep.h
index 8da3e8effafa..940c1b075659 100644
--- a/tools/include/linux/lockdep.h
+++ b/tools/include/linux/lockdep.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LOCKDEP_H_
 #define _LIBLOCKDEP_LOCKDEP_H_
 
diff --git a/tools/include/linux/module.h b/tools/include/linux/module.h
index 07055db296f3..2c999abf68e7 100644
--- a/tools/include/linux/module.h
+++ b/tools/include/linux/module.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LINUX_MODULE_H_
 #define _LIBLOCKDEP_LINUX_MODULE_H_
 
diff --git a/tools/include/linux/poison.h b/tools/include/linux/poison.h
index 51334edec506..4bf6777a8a03 100644
--- a/tools/include/linux/poison.h
+++ b/tools/include/linux/poison.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_POISON_H
 #define _LINUX_POISON_H
 
diff --git a/tools/include/linux/rcu.h b/tools/include/linux/rcu.h
index 5080649dad04..7d02527e5bce 100644
--- a/tools/include/linux/rcu.h
+++ b/tools/include/linux/rcu.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_RCU_H_
 #define _LIBLOCKDEP_RCU_H_
 
diff --git a/tools/include/linux/refcount.h b/tools/include/linux/refcount.h
index a0177c1f55b1..36cb29bc57c2 100644
--- a/tools/include/linux/refcount.h
+++ b/tools/include/linux/refcount.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_REFCOUNT_H
 #define _TOOLS_LINUX_REFCOUNT_H
 
diff --git a/tools/include/linux/spinlock.h b/tools/include/linux/spinlock.h
index 417cda4f793f..4ed569fcb139 100644
--- a/tools/include/linux/spinlock.h
+++ b/tools/include/linux/spinlock.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __LINUX_SPINLOCK_H_
 #define __LINUX_SPINLOCK_H_
 
diff --git a/tools/include/linux/stacktrace.h b/tools/include/linux/stacktrace.h
index 39aecc6b19d1..ae343ac35bfa 100644
--- a/tools/include/linux/stacktrace.h
+++ b/tools/include/linux/stacktrace.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LIBLOCKDEP_LINUX_STACKTRACE_H_
 #define _LIBLOCKDEP_LINUX_STACKTRACE_H_
 
diff --git a/tools/include/linux/string.h b/tools/include/linux/string.h
index a30fad536f52..6c3e2cc274c5 100644
--- a/tools/include/linux/string.h
+++ b/tools/include/linux/string.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_STRING_H_
 #define _TOOLS_LINUX_STRING_H_
 
diff --git a/tools/include/linux/stringify.h b/tools/include/linux/stringify.h
index 841cec8ed525..60e2c187da2c 100644
--- a/tools/include/linux/stringify.h
+++ b/tools/include/linux/stringify.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef __LINUX_STRINGIFY_H
 #define __LINUX_STRINGIFY_H
 
diff --git a/tools/include/linux/time64.h b/tools/include/linux/time64.h
index df9265483d65..55fa644b95fd 100644
--- a/tools/include/linux/time64.h
+++ b/tools/include/linux/time64.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_TIME64_H
 #define _TOOLS_LINUX_TIME64_H
 
diff --git a/tools/include/linux/types.h b/tools/include/linux/types.h
index 77a28a26a670..154eb4e3ca7c 100644
--- a/tools/include/linux/types.h
+++ b/tools/include/linux/types.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _TOOLS_LINUX_TYPES_H_
 #define _TOOLS_LINUX_TYPES_H_
 
diff --git a/tools/include/linux/unaligned/packed_struct.h b/tools/include/linux/unaligned/packed_struct.h
index c0d817de4df2..dbd93c7df2e1 100644
--- a/tools/include/linux/unaligned/packed_struct.h
+++ b/tools/include/linux/unaligned/packed_struct.h
@@ -1,3 +1,4 @@
+/* SPDX-License-Identifier: GPL-2.0 */
 #ifndef _LINUX_UNALIGNED_PACKED_STRUCT_H
 #define _LINUX_UNALIGNED_PACKED_STRUCT_H