libpayload: Introduce new Kconfig to explicitly allow GPL code

There have been leaks of GPL code into libpayload for a while now, for
new features or improvements that require third party code with no
adequate alternative among BSD-licensed software. It seems silly and
counter-productive to keep holding back features and performance
improvements from libpayload for a use-case (proprietary payloads) that
doesn't even seem to be implemented anywhere to date. Open-source
payloads should not need to suffer to appease commercial ones.

Instead, this patch introduces a new Kconfig option to explicitly allow
inclusion of GPL code. It will use Kconfig dependencies and/or Makefile
rules to ensure that no GPL code can end up in the final payload if that
option is unset, allowing proprietary payloads to keep working with the
existing BSD-licensed feature set. New features and patches (that are
sufficiently separate and self-contained to allow guarding through this
config option) can choose whether to import GPL code, and need to depend
on this option if they do.

Also clean up all (known) existing uses of GPL code to depend on the new
option, add some recent third-party imports to the LICENSES file, and
relicense the selfboot.c files to BSD with permission of the author.

BUG=chrome-os-partner:24957
TEST=Compiled Falco and Nyan_Big both with and without the new option,
disassembled output binaries to ensure that memcpy() looks as expected.

Original-Change-Id: I6e3a75b1a8e46291c75a876844c7a01f7d3f2a0e
Original-Signed-off-by: Julius Werner <jwerner@chromium.org>
Original-Signed-off-by: Hung-Te Lin <hungte@chromium.org>
Original-Reviewed-on: https://chromium-review.googlesource.com/203513
Original-Reviewed-by: Stefan Reinauer <reinauer@chromium.org>
(cherry picked from commit d8e5a9fdf583b5ac861f34baea6a16c4d8536512)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: I446fef028264c793b946dd9f765e446bf708b4db
Reviewed-on: http://review.coreboot.org/8118
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>

2 files changed, 26 insertions, 17 deletions

diff --git a/payloads/libpayload/arch/x86/Makefile.inc b/payloads/libpayload/arch/x86/Makefile.inc
index d9cc19e5db..503901dff2 100644
--- a/payloads/libpayload/arch/x86/Makefile.inc
+++ b/payloads/libpayload/arch/x86/Makefile.inc
@@ -32,9 +32,12 @@ libc-y += main.c sysinfo.c
 libc-y += timer.c coreboot.c util.S
 libc-y += exec.S virtual.c
 libc-y += selfboot.c
-libc-y += string.c
 libc-y += exception_asm.S exception.c
 
+# Will fall back to default_memXXX() in libc/memory.c if GPL not allowed.
+libc-$(CONFIG_LP_GPL) += string.c
+
+
 libcbfs-$(CONFIG_LP_CBFS) += rom_media.c
 
 # Multiboot support is configurable
diff --git a/payloads/libpayload/arch/x86/selfboot.c b/payloads/libpayload/arch/x86/selfboot.c
index fc89859643..5c3e4459e9 100644
--- a/payloads/libpayload/arch/x86/selfboot.c
+++ b/payloads/libpayload/arch/x86/selfboot.c
@@ -1,24 +1,30 @@
 /*
  * Copyright 2014 Google Inc.
  *
- * See file CREDITS for list of people who contributed to this
- * project.
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ * 3. The name of the author may not be used to endorse or promote products
+ *    derived from this software without specific prior written permission.
  *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License as
- * published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but without any warranty; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
- * MA 02111-1307 USA
+ * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+ * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+ * SUCH DAMAGE.
  */
+
 #include <libpayload.h>
 
 void selfboot(void *entry)