diff options
Diffstat (limited to 'drivers/char/random.c')
| -rw-r--r-- | drivers/char/random.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index d3bb7927fb49..914b1575df8f 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -250,6 +250,7 @@ #include <linux/interrupt.h> #include <linux/mm.h> #include <linux/spinlock.h> +#include <linux/kthread.h> #include <linux/percpu.h> #include <linux/cryptohash.h> #include <linux/fips.h> @@ -1750,3 +1751,23 @@ randomize_range(unsigned long start, unsigned long end, unsigned long len) return 0; return PAGE_ALIGN(get_random_int() % range + start); } + +/* Interface for in-kernel drivers of true hardware RNGs. + * Those devices may produce endless random bits and will be throttled + * when our pool is full. + */ +void add_hwgenerator_randomness(const char *buffer, size_t count, + size_t entropy) +{ + struct entropy_store *poolp = &input_pool; + + /* Suspend writing if we're above the trickle threshold. + * We'll be woken up again once below random_write_wakeup_thresh, + * or when the calling thread is about to terminate. + */ + wait_event_interruptible(random_write_wait, kthread_should_stop() || + ENTROPY_BITS(&input_pool) <= random_write_wakeup_bits); + mix_pool_bytes(poolp, buffer, count); + credit_entropy_bits(poolp, entropy); +} +EXPORT_SYMBOL_GPL(add_hwgenerator_randomness); |