File-copy from v4.4.100

This is the result of 'cp' from a linux-stable tree with the 'v4.4.100'
tag checked out (commit 26d6298789e695c9f627ce49a7bbd2286405798a) on
git://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git

Please refer to that tree for all history prior to this point.

Change-Id: I8a9ee2aea93cd29c52c847d0ce33091a73ae6afe
diff --git a/arch/microblaze/kernel/stacktrace.c b/arch/microblaze/kernel/stacktrace.c
new file mode 100644
index 0000000..b4debe2
--- /dev/null
+++ b/arch/microblaze/kernel/stacktrace.c
@@ -0,0 +1,31 @@
+/*
+ * Stack trace support for Microblaze.
+ *
+ * Copyright (C) 2009 Michal Simek <monstr@monstr.eu>
+ * Copyright (C) 2009 PetaLogix
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <linux/thread_info.h>
+#include <linux/ptrace.h>
+#include <asm/unwind.h>
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	/* Exclude our helper functions from the trace*/
+	trace->skip += 2;
+	microblaze_unwind(NULL, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+	microblaze_unwind(tsk, trace);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);