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, 49 insertions, 0 deletions

diff --git a/kernel/arch/um/kernel/sigio.c b/kernel/arch/um/kernel/sigio.c
new file mode 100644
index 000000000..b5e0cbb34
--- /dev/null
+++ b/kernel/arch/um/kernel/sigio.c
@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2002 - 2007 Jeff Dike (jdike@{linux.intel,addtoit}.com)
+ * Licensed under the GPL
+ */
+
+#include <linux/interrupt.h>
+#include <irq_kern.h>
+#include <os.h>
+#include <sigio.h>
+
+/* Protected by sigio_lock() called from write_sigio_workaround */
+static int sigio_irq_fd = -1;
+
+static irqreturn_t sigio_interrupt(int irq, void *data)
+{
+	char c;
+
+	os_read_file(sigio_irq_fd, &c, sizeof(c));
+	reactivate_fd(sigio_irq_fd, SIGIO_WRITE_IRQ);
+	return IRQ_HANDLED;
+}
+
+int write_sigio_irq(int fd)
+{
+	int err;
+
+	err = um_request_irq(SIGIO_WRITE_IRQ, fd, IRQ_READ, sigio_interrupt,
+			     0, "write sigio", NULL);
+	if (err) {
+		printk(KERN_ERR "write_sigio_irq : um_request_irq failed, "
+		       "err = %d\n", err);
+		return -1;
+	}
+	sigio_irq_fd = fd;
+	return 0;
+}
+
+/* These are called from os-Linux/sigio.c to protect its pollfds arrays. */
+static DEFINE_SPINLOCK(sigio_spinlock);
+
+void sigio_lock(void)
+{
+	spin_lock(&sigio_spinlock);
+}
+
+void sigio_unlock(void)
+{
+	spin_unlock(&sigio_spinlock);
+}