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, 91 insertions, 0 deletions

diff --git a/kernel/arch/arm/plat-versatile/platsmp.c b/kernel/arch/arm/plat-versatile/platsmp.c
new file mode 100644
index 000000000..b4a8d54fc
--- /dev/null
+++ b/kernel/arch/arm/plat-versatile/platsmp.c
@@ -0,0 +1,91 @@
+/*
+ *  linux/arch/arm/plat-versatile/platsmp.c
+ *
+ *  Copyright (C) 2002 ARM Ltd.
+ *  All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/init.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/jiffies.h>
+#include <linux/smp.h>
+
+#include <asm/cacheflush.h>
+#include <asm/smp_plat.h>
+
+/*
+ * Write pen_release in a way that is guaranteed to be visible to all
+ * observers, irrespective of whether they're taking part in coherency
+ * or not.  This is necessary for the hotplug code to work reliably.
+ */
+static void write_pen_release(int val)
+{
+	pen_release = val;
+	smp_wmb();
+	sync_cache_w(&pen_release);
+}
+
+static DEFINE_RAW_SPINLOCK(boot_lock);
+
+void versatile_secondary_init(unsigned int cpu)
+{
+	/*
+	 * let the primary processor know we're out of the
+	 * pen, then head off into the C entry point
+	 */
+	write_pen_release(-1);
+
+	/*
+	 * Synchronise with the boot thread.
+	 */
+	raw_spin_lock(&boot_lock);
+	raw_spin_unlock(&boot_lock);
+}
+
+int versatile_boot_secondary(unsigned int cpu, struct task_struct *idle)
+{
+	unsigned long timeout;
+
+	/*
+	 * Set synchronisation state between this boot processor
+	 * and the secondary one
+	 */
+	raw_spin_lock(&boot_lock);
+
+	/*
+	 * This is really belt and braces; we hold unintended secondary
+	 * CPUs in the holding pen until we're ready for them.  However,
+	 * since we haven't sent them a soft interrupt, they shouldn't
+	 * be there.
+	 */
+	write_pen_release(cpu_logical_map(cpu));
+
+	/*
+	 * Send the secondary CPU a soft interrupt, thereby causing
+	 * the boot monitor to read the system wide flags register,
+	 * and branch to the address found there.
+	 */
+	arch_send_wakeup_ipi_mask(cpumask_of(cpu));
+
+	timeout = jiffies + (1 * HZ);
+	while (time_before(jiffies, timeout)) {
+		smp_rmb();
+		if (pen_release == -1)
+			break;
+
+		udelay(10);
+	}
+
+	/*
+	 * now the secondary core is starting up let it run its
+	 * calibrations, then wait for it to finish
+	 */
+	raw_spin_unlock(&boot_lock);
+
+	return pen_release != -1 ? -ENOSYS : 0;
+}