libpayload: Add support for arm64 in libpayload

Basic support for arm64 is enabled in libpayload.
Features added:
1) mem* operations in assembly.
2) Basic exception handling and support for testing exceptions.
3) Caching support.

Tested with arm64-generic board compilation.

BUG=None
BRANCH=None
TEST=Compilation successful

Original-Change-Id: I4e86301f9c6383abc078e2b70071fb84bd6e4741
Original-Signed-off-by: Furquan Shaikh <furquan@google.com>
Original-Reviewed-on: https://chromium-review.googlesource.com/187067
Original-Tested-by: Furquan Shaikh <furquan@chromium.org>
Original-Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Original-Commit-Queue: Furquan Shaikh <furquan@chromium.org>
(cherry picked from commit a70d13f3d225535843ab352290eab2e1ec7a9b4b)
Signed-off-by: Marc Jones <marc.jones@se-eng.com>

Change-Id: Ie3affe6a2bdd4fed3058de739d4c6aa573e5b251
Reviewed-on: http://review.coreboot.org/8063
Tested-by: build bot (Jenkins)
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
Reviewed-by: Furquan Shaikh <furquan@google.com>

payloads/libpayload/arch/arm64/main.c

@@ -0,0 +1,82 @@
+/*
+ * This file is part of the libpayload project.
+ *
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * 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 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 <exception.h>
+#include <libpayload.h>
+
+unsigned int main_argc;    /**< The argc value to pass to main() */
+
+/** The argv value to pass to main() */
+char *main_argv[MAX_ARGC_COUNT];
+
+unsigned int test_exc;
+
+int test_exception(void);
+int test_exception(void)
+{
+	int a = 1;
+	int b = 0;
+	test_exc = 1;
+	return a/b;
+}
+
+/**
+ * This is our C entry function - set up the system
+ * and jump into the payload entry point.
+ */
+void start_main(void);
+void start_main(void)
+{
+	extern int main(int argc, char **argv);
+
+	printf("hello libpayload world");
+	/* Gather system information. */
+	lib_get_sysinfo();
+
+
+	exception_init();
+
+	test_exception();
+	/*
+	 * Any other system init that has to happen before the
+	 * user gets control goes here.
+	 */
+
+	/*
+	 * Go to the entry point.
+	 * In the future we may care about the return value.
+	 */
+
+	(void) main(main_argc, (main_argc != 0) ? main_argv : NULL);
+
+	/*
+	 * Returning here will go to the _leave function to return
+	 * us to the original context.
+	 */
+}