diff options
| -rw-r--r-- | drivers/char/hw_random/core.c | 69 |
1 files changed, 64 insertions, 5 deletions
diff --git a/drivers/char/hw_random/core.c b/drivers/char/hw_random/core.c index 334601c..48b3c81 100644 --- a/drivers/char/hw_random/core.c +++ b/drivers/char/hw_random/core.c @@ -38,6 +38,7 @@ #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> @@ -50,10 +51,18 @@ 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 = 700; /* an arbitrary 70% */ + +module_param(current_quality, ushort, 0644); +MODULE_PARM_DESC(current_quality, + "current hwrng entropy estimation per mill"); + +static void start_khwrngd(void); static size_t rng_buffer_size(void) { @@ -62,9 +71,18 @@ static size_t rng_buffer_size(void) static inline int hwrng_init(struct hwrng *rng) { - if (!rng->init) - return 0; - return rng->init(rng); + int err; + + if (rng->init) { + err = rng->init(rng); + if (err) + return err; + } + + if (current_quality > 0 && !hwrng_fill) + start_khwrngd(); + + return 0; } static inline void hwrng_cleanup(struct hwrng *rng) @@ -300,6 +318,36 @@ err_misc_dereg: 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)>>10); + } + hwrng_fill = 0; + 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; @@ -320,6 +368,13 @@ int hwrng_register(struct hwrng *rng) 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; @@ -375,8 +430,11 @@ void hwrng_unregister(struct hwrng *rng) 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); } @@ -387,6 +445,7 @@ static void __exit hwrng_exit(void) mutex_lock(&rng_mutex); BUG_ON(current_rng); kfree(rng_buffer); + kfree(rng_fillbuf); mutex_unlock(&rng_mutex); } |
