Commit c84dbf61 authored by Torsten Duwe's avatar Torsten Duwe Committed by Theodore Ts'o

random: add_hwgenerator_randomness() for feeding entropy from devices

This patch adds an interface to the random pool for feeding entropy
in-kernel.
Signed-off-by: default avatarTorsten Duwe <duwe@suse.de>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent 43759d4f
......@@ -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);
......@@ -47,5 +47,7 @@ struct hwrng {
extern int hwrng_register(struct hwrng *rng);
/** Unregister a Hardware Random Number Generator driver. */
extern void hwrng_unregister(struct hwrng *rng);
/** Feed random bits into the pool. */
extern void add_hwgenerator_randomness(const char *buffer, size_t count, size_t entropy);
#endif /* LINUX_HWRANDOM_H_ */
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