Add the rt linux 4.1.3-rt3 as base

Import the rt linux 4.1.3-rt3 as OPNFV kvm base.

It's from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git linux-4.1.y-rt and
the base is:

commit 0917f823c59692d751951bf5ea699a2d1e2f26a2
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date:   Sat Jul 25 12:13:34 2015 +0200

    Prepare v4.1.3-rt3

    Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

We lose all the git history this way and it's not good. We
should apply another opnfv project repo in future.

Change-Id: I87543d81c9df70d99c5001fbdf646b202c19f423
Signed-off-by: Yunhong Jiang <yunhong.jiang@intel.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/kernel/arch/powerpc/kernel/stacktrace.c b/kernel/arch/powerpc/kernel/stacktrace.c
new file mode 100644
index 000000000..ea43a347a
--- /dev/null
+++ b/kernel/arch/powerpc/kernel/stacktrace.c
@@ -0,0 +1,63 @@
+/*
+ * Stack trace utility
+ *
+ * Copyright 2008 Christoph Hellwig, IBM Corp.
+ *
+ *
+ *      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.
+ */
+
+#include <linux/export.h>
+#include <linux/sched.h>
+#include <linux/stacktrace.h>
+#include <asm/ptrace.h>
+#include <asm/processor.h>
+
+/*
+ * Save stack-backtrace addresses into a stack_trace buffer.
+ */
+static void save_context_stack(struct stack_trace *trace, unsigned long sp,
+			struct task_struct *tsk, int savesched)
+{
+	for (;;) {
+		unsigned long *stack = (unsigned long *) sp;
+		unsigned long newsp, ip;
+
+		if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
+			return;
+
+		newsp = stack[0];
+		ip = stack[STACK_FRAME_LR_SAVE];
+
+		if (savesched || !in_sched_functions(ip)) {
+			if (!trace->skip)
+				trace->entries[trace->nr_entries++] = ip;
+			else
+				trace->skip--;
+		}
+
+		if (trace->nr_entries >= trace->max_entries)
+			return;
+
+		sp = newsp;
+	}
+}
+
+void save_stack_trace(struct stack_trace *trace)
+{
+	unsigned long sp;
+
+	sp = current_stack_pointer();
+
+	save_context_stack(trace, sp, current, 1);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace);
+
+void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
+{
+	save_context_stack(trace, tsk->thread.ksp, tsk, 0);
+}
+EXPORT_SYMBOL_GPL(save_stack_trace_tsk);