1 files changed, 167 insertions, 0 deletions
diff --git a/kernel/arch/um/drivers/random.c b/kernel/arch/um/drivers/random.c
new file mode 100644
index 000000000..dd16c902f
--- /dev/null
+++ b/kernel/arch/um/drivers/random.c
@@ -0,0 +1,167 @@
+/* Copyright (C) 2005 - 2008 Jeff Dike <jdike@{linux.intel,addtoit}.com> */
+
+/* Much of this ripped from drivers/char/hw_random.c, see there for other
+ * copyright.
+ *
+ * This software may be used and distributed according to the terms
+ * of the GNU General Public License, incorporated herein by reference.
+ */
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/miscdevice.h>
+#include <linux/delay.h>
+#include <asm/uaccess.h>
+#include <irq_kern.h>
+#include <os.h>
+
+/*
+ * core module and version information
+ */
+#define RNG_VERSION "1.0.0"
+#define RNG_MODULE_NAME "hw_random"
+
+#define RNG_MISCDEV_MINOR		183 /* official */
+
+/* Changed at init time, in the non-modular case, and at module load
+ * time, in the module case.  Presumably, the module subsystem
+ * protects against a module being loaded twice at the same time.
+ */
+static int random_fd = -1;
+static DECLARE_WAIT_QUEUE_HEAD(host_read_wait);
+
+static int rng_dev_open (struct inode *inode, struct file *filp)
+{
+	/* enforce read-only access to this chrdev */
+	if ((filp->f_mode & FMODE_READ) == 0)
+		return -EINVAL;
+	if ((filp->f_mode & FMODE_WRITE) != 0)
+		return -EINVAL;
+
+	return 0;
+}
+
+static atomic_t host_sleep_count = ATOMIC_INIT(0);
+
+static ssize_t rng_dev_read (struct file *filp, char __user *buf, size_t size,
+			     loff_t *offp)
+{
+	u32 data;
+	int n, ret = 0, have_data;
+
+	while (size) {
+		n = os_read_file(random_fd, &data, sizeof(data));
+		if (n > 0) {
+			have_data = n;
+			while (have_data && size) {
+				if (put_user((u8) data, buf++)) {
+					ret = ret ? : -EFAULT;
+					break;
+				}
+				size--;
+				ret++;
+				have_data--;
+				data >>= 8;
+			}
+		}
+		else if (n == -EAGAIN) {
+			DECLARE_WAITQUEUE(wait, current);
+
+			if (filp->f_flags & O_NONBLOCK)
+				return ret ? : -EAGAIN;
+
+			atomic_inc(&host_sleep_count);
+			reactivate_fd(random_fd, RANDOM_IRQ);
+			add_sigio_fd(random_fd);
+
+			add_wait_queue(&host_read_wait, &wait);
+			set_task_state(current, TASK_INTERRUPTIBLE);
+
+			schedule();
+			remove_wait_queue(&host_read_wait, &wait);
+
+			if (atomic_dec_and_test(&host_sleep_count)) {
+				ignore_sigio_fd(random_fd);
+				deactivate_fd(random_fd, RANDOM_IRQ);
+			}
+		}
+		else
+			return n;
+
+		if (signal_pending (current))
+			return ret ? : -ERESTARTSYS;
+	}
+	return ret;
+}
+
+static const struct file_operations rng_chrdev_ops = {
+	.owner		= THIS_MODULE,
+	.open		= rng_dev_open,
+	.read		= rng_dev_read,
+	.llseek		= noop_llseek,
+};
+
+/* rng_init shouldn't be called more than once at boot time */
+static struct miscdevice rng_miscdev = {
+	RNG_MISCDEV_MINOR,
+	RNG_MODULE_NAME,
+	&rng_chrdev_ops,
+};
+
+static irqreturn_t random_interrupt(int irq, void *data)
+{
+	wake_up(&host_read_wait);
+
+	return IRQ_HANDLED;
+}
+
+/*
+ * rng_init - initialize RNG module
+ */
+static int __init rng_init (void)
+{
+	int err;
+
+	err = os_open_file("/dev/random", of_read(OPENFLAGS()), 0);
+	if (err < 0)
+		goto out;
+
+	random_fd = err;
+
+	err = um_request_irq(RANDOM_IRQ, random_fd, IRQ_READ, random_interrupt,
+			     0, "random", NULL);
+	if (err)
+		goto err_out_cleanup_hw;
+
+	sigio_broken(random_fd, 1);
+
+	err = misc_register (&rng_miscdev);
+	if (err) {
+		printk (KERN_ERR RNG_MODULE_NAME ": misc device register "
+			"failed\n");
+		goto err_out_cleanup_hw;
+	}
+out:
+	return err;
+
+err_out_cleanup_hw:
+	os_close_file(random_fd);
+	random_fd = -1;
+	goto out;
+}
+
+/*
+ * rng_cleanup - shutdown RNG module
+ */
+static void __exit rng_cleanup (void)
+{
+	os_close_file(random_fd);
+	misc_deregister (&rng_miscdev);
+}
+
+module_init (rng_init);
+module_exit (rng_cleanup);
+
+MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
+MODULE_LICENSE("GPL");