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, 125 insertions, 0 deletions

diff --git a/kernel/arch/um/drivers/slirp_user.c b/kernel/arch/um/drivers/slirp_user.c
new file mode 100644
index 000000000..c999d187a
--- /dev/null
+++ b/kernel/arch/um/drivers/slirp_user.c
@@ -0,0 +1,125 @@
+/*
+ * Copyright (C) 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
+ * Licensed under the GPL.
+ */
+
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <sys/wait.h>
+#include <net_user.h>
+#include <os.h>
+#include "slirp.h"
+
+static int slirp_user_init(void *data, void *dev)
+{
+	struct slirp_data *pri = data;
+
+	pri->dev = dev;
+	return 0;
+}
+
+struct slirp_pre_exec_data {
+	int stdin;
+	int stdout;
+};
+
+static void slirp_pre_exec(void *arg)
+{
+	struct slirp_pre_exec_data *data = arg;
+
+	if (data->stdin != -1)
+		dup2(data->stdin, 0);
+	if (data->stdout != -1)
+		dup2(data->stdout, 1);
+}
+
+static int slirp_tramp(char **argv, int fd)
+{
+	struct slirp_pre_exec_data pe_data;
+	int pid;
+
+	pe_data.stdin = fd;
+	pe_data.stdout = fd;
+	pid = run_helper(slirp_pre_exec, &pe_data, argv);
+
+	return pid;
+}
+
+static int slirp_open(void *data)
+{
+	struct slirp_data *pri = data;
+	int fds[2], pid, err;
+
+	err = os_pipe(fds, 1, 1);
+	if (err)
+		return err;
+
+	err = slirp_tramp(pri->argw.argv, fds[1]);
+	if (err < 0) {
+		printk(UM_KERN_ERR "slirp_tramp failed - errno = %d\n", -err);
+		goto out;
+	}
+	pid = err;
+
+	pri->slave = fds[1];
+	pri->slip.pos = 0;
+	pri->slip.esc = 0;
+	pri->pid = err;
+
+	return fds[0];
+out:
+	close(fds[0]);
+	close(fds[1]);
+	return err;
+}
+
+static void slirp_close(int fd, void *data)
+{
+	struct slirp_data *pri = data;
+	int err;
+
+	close(fd);
+	close(pri->slave);
+
+	pri->slave = -1;
+
+	if (pri->pid<1) {
+		printk(UM_KERN_ERR "slirp_close: no child process to shut "
+		       "down\n");
+		return;
+	}
+
+#if 0
+	if (kill(pri->pid, SIGHUP)<0) {
+		printk(UM_KERN_ERR "slirp_close: sending hangup to %d failed "
+		       "(%d)\n", pri->pid, errno);
+	}
+#endif
+	err = helper_wait(pri->pid);
+	if (err < 0)
+		return;
+
+	pri->pid = -1;
+}
+
+int slirp_user_read(int fd, void *buf, int len, struct slirp_data *pri)
+{
+	return slip_proto_read(fd, buf, len, &pri->slip);
+}
+
+int slirp_user_write(int fd, void *buf, int len, struct slirp_data *pri)
+{
+	return slip_proto_write(fd, buf, len, &pri->slip);
+}
+
+const struct net_user_info slirp_user_info = {
+	.init		= slirp_user_init,
+	.open		= slirp_open,
+	.close	 	= slirp_close,
+	.remove	 	= NULL,
+	.add_address	= NULL,
+	.delete_address = NULL,
+	.mtu		= BUF_SIZE,
+	.max_packet	= BUF_SIZE,
+};