#include <linux/fs.h>
#include <linux/sched.h>
#include <linux/miscdevice.h>
+#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/slab.h>
#include <linux/random.h>
static struct hwrng *current_rng;
+static struct task_struct *hwrng_fill;
static LIST_HEAD(rng_list);
static DEFINE_MUTEX(rng_mutex);
static int data_avail;
-static u8 *rng_buffer;
+static u8 *rng_buffer, *rng_fillbuf;
+static unsigned short current_quality;
+static unsigned short default_quality; /* = 0; default to "off" */
+
+module_param(current_quality, ushort, 0644);
+MODULE_PARM_DESC(current_quality,
+ "current hwrng entropy estimation per mill");
+module_param(default_quality, ushort, 0644);
+MODULE_PARM_DESC(default_quality,
+ "default entropy content of hwrng per mill");
+
+static void start_khwrngd(void);
static inline int rng_get_data(struct hwrng *rng, u8 *buffer, size_t size,
int wait);
return ret;
}
add_early_randomness(rng);
+
+ current_quality = rng->quality ? : default_quality;
+ current_quality &= 1023;
+
+ if (current_quality == 0 && hwrng_fill)
+ kthread_stop(hwrng_fill);
+ if (current_quality > 0 && !hwrng_fill)
+ start_khwrngd();
+
return 0;
}
goto out;
}
+static int hwrng_fillfn(void *unused)
+{
+ long rc;
+
+ while (!kthread_should_stop()) {
+ if (!current_rng)
+ break;
+ rc = rng_get_data(current_rng, rng_fillbuf,
+ rng_buffer_size(), 1);
+ if (rc <= 0) {
+ pr_warn("hwrng: no data available\n");
+ msleep_interruptible(10000);
+ continue;
+ }
+ add_hwgenerator_randomness((void *)rng_fillbuf, rc,
+ rc * current_quality * 8 >> 10);
+ }
+ hwrng_fill = NULL;
+ return 0;
+}
+
+static void start_khwrngd(void)
+{
+ hwrng_fill = kthread_run(hwrng_fillfn, NULL, "hwrng");
+ if (hwrng_fill == ERR_PTR(-ENOMEM)) {
+ pr_err("hwrng_fill thread creation failed");
+ hwrng_fill = NULL;
+ }
+}
+
int hwrng_register(struct hwrng *rng)
{
int err = -EINVAL;
if (!rng_buffer)
goto out_unlock;
}
+ if (!rng_fillbuf) {
+ rng_fillbuf = kmalloc(rng_buffer_size(), GFP_KERNEL);
+ if (!rng_fillbuf) {
+ kfree(rng_buffer);
+ goto out_unlock;
+ }
+ }
/* Must not register two RNGs with the same name. */
err = -EEXIST;
current_rng = NULL;
}
}
- if (list_empty(&rng_list))
+ if (list_empty(&rng_list)) {
unregister_miscdev();
+ if (hwrng_fill)
+ kthread_stop(hwrng_fill);
+ }
mutex_unlock(&rng_mutex);
}
mutex_lock(&rng_mutex);
BUG_ON(current_rng);
kfree(rng_buffer);
+ kfree(rng_fillbuf);
mutex_unlock(&rng_mutex);
}