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-rw-r--r--arch/um/drivers/random.c121
1 files changed, 121 insertions, 0 deletions
diff --git a/arch/um/drivers/random.c b/arch/um/drivers/random.c
new file mode 100644
index 0000000000..da985e0dc6
--- /dev/null
+++ b/arch/um/drivers/random.c
@@ -0,0 +1,121 @@
+/* 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/signal.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/interrupt.h>
+#include <linux/miscdevice.h>
+#include <linux/hw_random.h>
+#include <linux/delay.h>
+#include <linux/uaccess.h>
+#include <init.h>
+#include <irq_kern.h>
+#include <os.h>
+
+/*
+ * core module information
+ */
+#define RNG_MODULE_NAME "hw_random"
+
+/* 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 struct hwrng hwrng;
+static DECLARE_COMPLETION(have_data);
+
+static int rng_dev_read(struct hwrng *rng, void *buf, size_t max, bool block)
+{
+ int ret;
+
+ for (;;) {
+ ret = os_read_file(random_fd, buf, max);
+ if (block && ret == -EAGAIN) {
+ add_sigio_fd(random_fd);
+
+ ret = wait_for_completion_killable(&have_data);
+
+ ignore_sigio_fd(random_fd);
+ deactivate_fd(random_fd, RANDOM_IRQ);
+
+ if (ret < 0)
+ break;
+ } else {
+ break;
+ }
+ }
+
+ return ret != -EAGAIN ? ret : 0;
+}
+
+static irqreturn_t random_interrupt(int irq, void *data)
+{
+ complete(&have_data);
+
+ 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 < 0)
+ goto err_out_cleanup_hw;
+
+ sigio_broken(random_fd);
+ hwrng.name = RNG_MODULE_NAME;
+ hwrng.read = rng_dev_read;
+
+ err = hwrng_register(&hwrng);
+ if (err) {
+ pr_err(RNG_MODULE_NAME " registering failed (%d)\n", err);
+ 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 cleanup(void)
+{
+ free_irq_by_fd(random_fd);
+ os_close_file(random_fd);
+}
+
+static void __exit rng_cleanup(void)
+{
+ hwrng_unregister(&hwrng);
+ os_close_file(random_fd);
+}
+
+module_init (rng_init);
+module_exit (rng_cleanup);
+__uml_exitcall(cleanup);
+
+MODULE_DESCRIPTION("UML Host Random Number Generator (RNG) driver");
+MODULE_LICENSE("GPL");