xz: switch from public domain to BSD Zero Clause License (0BSD)

Remove the public domain notices and add SPDX license identifiers.

Change MODULE_LICENSE from "GPL" to "Dual BSD/GPL" because 0BSD should
count as a BSD license variant here.

The switch to 0BSD was done in the upstream XZ Embedded project because
public domain has (real or perceived) legal issues in some jurisdictions.

Link: https://lkml.kernel.org/r/20240721133633.47721-4-lasse.collin@tukaani.org
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Reviewed-by: Sam James <sam@gentoo.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Emil Renner Berthing <emil.renner.berthing@canonical.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Joel Stanley <joel@jms.id.au>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Jubin Zhong <zhongjubin@huawei.com>
Cc: Jules Maselbas <jmaselbas@zdiv.net>
Cc: Krzysztof Kozlowski <krzk@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Rui Li <me@lirui.org>
Cc: Simon Glass <sjg@chromium.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

13 files changed, 27 insertions, 52 deletions

diff --git a/include/linux/decompress/unxz.h b/include/linux/decompress/unxz.h
index f764e2a7201e..3dd2658a9dab 100644
--- a/include/linux/decompress/unxz.h
+++ b/include/linux/decompress/unxz.h
@@ -1,10 +1,9 @@
+/* SPDX-License-Identifier: 0BSD */
+
 /*
  * Wrapper for decompressing XZ-compressed kernel, initramfs, and initrd
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #ifndef DECOMPRESS_UNXZ_H
diff --git a/include/linux/xz.h b/include/linux/xz.h
index 7285ca5d56e9..5728d57aecc0 100644
--- a/include/linux/xz.h
+++ b/include/linux/xz.h
@@ -1,11 +1,10 @@
+/* SPDX-License-Identifier: 0BSD */
+
 /*
  * XZ decompressor
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
  *          Igor Pavlov <https://7-zip.org/>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #ifndef XZ_H
diff --git a/lib/decompress_unxz.c b/lib/decompress_unxz.c
index 842894158944..34bb7efc0412 100644
--- a/lib/decompress_unxz.c
+++ b/lib/decompress_unxz.c
@@ -1,10 +1,9 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * Wrapper for decompressing XZ-compressed kernel, initramfs, and initrd
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 /*
diff --git a/lib/xz/xz_crc32.c b/lib/xz/xz_crc32.c
index 88a2c35e1b59..30b8a27110b1 100644
--- a/lib/xz/xz_crc32.c
+++ b/lib/xz/xz_crc32.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * CRC32 using the polynomial from IEEE-802.3
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
  *          Igor Pavlov <https://7-zip.org/>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 /*
diff --git a/lib/xz/xz_dec_bcj.c b/lib/xz/xz_dec_bcj.c
index ef449e97d1a1..ab9237ed6db8 100644
--- a/lib/xz/xz_dec_bcj.c
+++ b/lib/xz/xz_dec_bcj.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * Branch/Call/Jump (BCJ) filter decoders
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
  *          Igor Pavlov <https://7-zip.org/>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #include "xz_private.h"
diff --git a/lib/xz/xz_dec_lzma2.c b/lib/xz/xz_dec_lzma2.c
index 27ce34520e78..613939f5dd6c 100644
--- a/lib/xz/xz_dec_lzma2.c
+++ b/lib/xz/xz_dec_lzma2.c
@@ -1,11 +1,10 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * LZMA2 decoder
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
  *          Igor Pavlov <https://7-zip.org/>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #include "xz_private.h"
diff --git a/lib/xz/xz_dec_stream.c b/lib/xz/xz_dec_stream.c
index 683570b93a8c..0058406ccd17 100644
--- a/lib/xz/xz_dec_stream.c
+++ b/lib/xz/xz_dec_stream.c
@@ -1,10 +1,9 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * .xz Stream decoder
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #include "xz_private.h"
diff --git a/lib/xz/xz_dec_syms.c b/lib/xz/xz_dec_syms.c
index 61098c67a413..495d2cc2e6e8 100644
--- a/lib/xz/xz_dec_syms.c
+++ b/lib/xz/xz_dec_syms.c
@@ -1,10 +1,9 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * XZ decoder module information
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #include <linux/module.h>
@@ -25,9 +24,4 @@ EXPORT_SYMBOL(xz_dec_microlzma_end);
 MODULE_DESCRIPTION("XZ decompressor");
 MODULE_VERSION("1.1");
 MODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org> and Igor Pavlov");
-
-/*
- * This code is in the public domain, but in Linux it's simplest to just
- * say it's GPL and consider the authors as the copyright holders.
- */
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/lib/xz/xz_dec_test.c b/lib/xz/xz_dec_test.c
index da28a19d6c98..53d3600f2ddb 100644
--- a/lib/xz/xz_dec_test.c
+++ b/lib/xz/xz_dec_test.c
@@ -1,10 +1,9 @@
+// SPDX-License-Identifier: 0BSD
+
 /*
  * XZ decoder tester
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #include <linux/kernel.h>
@@ -212,9 +211,4 @@ module_exit(xz_dec_test_exit);
 MODULE_DESCRIPTION("XZ decompressor tester");
 MODULE_VERSION("1.0");
 MODULE_AUTHOR("Lasse Collin <lasse.collin@tukaani.org>");
-
-/*
- * This code is in the public domain, but in Linux it's simplest to just
- * say it's GPL and consider the authors as the copyright holders.
- */
-MODULE_LICENSE("GPL");
+MODULE_LICENSE("Dual BSD/GPL");
diff --git a/lib/xz/xz_lzma2.h b/lib/xz/xz_lzma2.h
index 92d852d4f87a..d2632b7dfb9c 100644
--- a/lib/xz/xz_lzma2.h
+++ b/lib/xz/xz_lzma2.h
@@ -1,11 +1,10 @@
+/* SPDX-License-Identifier: 0BSD */
+
 /*
  * LZMA2 definitions
  *
  * Authors: Lasse Collin <lasse.collin@tukaani.org>
  *          Igor Pavlov <https://7-zip.org/>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #ifndef XZ_LZMA2_H
diff --git a/lib/xz/xz_private.h b/lib/xz/xz_private.h
index bf1e94ec7873..2412a5d54801 100644
--- a/lib/xz/xz_private.h
+++ b/lib/xz/xz_private.h
@@ -1,10 +1,9 @@
+/* SPDX-License-Identifier: 0BSD */
+
 /*
  * Private includes and definitions
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #ifndef XZ_PRIVATE_H
diff --git a/lib/xz/xz_stream.h b/lib/xz/xz_stream.h
index 430bb3a0d195..55f9f6f94b78 100644
--- a/lib/xz/xz_stream.h
+++ b/lib/xz/xz_stream.h
@@ -1,10 +1,9 @@
+/* SPDX-License-Identifier: 0BSD */
+
 /*
  * Definitions for handling the .xz file format
  *
  * Author: Lasse Collin <lasse.collin@tukaani.org>
- *
- * This file has been put into the public domain.
- * You can do whatever you want with this file.
  */
 
 #ifndef XZ_STREAM_H
diff --git a/scripts/xz_wrap.sh b/scripts/xz_wrap.sh
index d06baf626abe..bb760b721b2c 100755
--- a/scripts/xz_wrap.sh
+++ b/scripts/xz_wrap.sh
@@ -1,13 +1,10 @@
 #!/bin/sh
+# SPDX-License-Identifier: 0BSD
 #
 # This is a wrapper for xz to compress the kernel image using appropriate
 # compression options depending on the architecture.
 #
 # Author: Lasse Collin <lasse.collin@tukaani.org>
-#
-# This file has been put into the public domain.
-# You can do whatever you want with this file.
-#
 
 BCJ=
 LZMA2OPTS=