diff options
Diffstat (limited to 'include/linux/prandom.h')
-rw-r--r-- | include/linux/prandom.h | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/include/linux/prandom.h b/include/linux/prandom.h new file mode 100644 index 000000000..1f4a0de7b --- /dev/null +++ b/include/linux/prandom.h @@ -0,0 +1,61 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * include/linux/prandom.h + * + * Include file for the fast pseudo-random 32-bit + * generation. + */ +#ifndef _LINUX_PRANDOM_H +#define _LINUX_PRANDOM_H + +#include <linux/types.h> +#include <linux/percpu.h> +#include <linux/random.h> + +struct rnd_state { + __u32 s1, s2, s3, s4; +}; + +u32 prandom_u32_state(struct rnd_state *state); +void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes); +void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state); + +#define prandom_init_once(pcpu_state) \ + DO_ONCE(prandom_seed_full_state, (pcpu_state)) + +/* Deprecated: use get_random_u32_below() instead. */ +static inline u32 prandom_u32_max(u32 ep_ro) +{ + return get_random_u32_below(ep_ro); +} + +/* + * Handle minimum values for seeds + */ +static inline u32 __seed(u32 x, u32 m) +{ + return (x < m) ? x + m : x; +} + +/** + * prandom_seed_state - set seed for prandom_u32_state(). + * @state: pointer to state structure to receive the seed. + * @seed: arbitrary 64-bit value to use as a seed. + */ +static inline void prandom_seed_state(struct rnd_state *state, u64 seed) +{ + u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL; + + state->s1 = __seed(i, 2U); + state->s2 = __seed(i, 8U); + state->s3 = __seed(i, 16U); + state->s4 = __seed(i, 128U); +} + +/* Pseudo random number generator from numerical recipes. */ +static inline u32 next_pseudo_random32(u32 seed) +{ + return seed * 1664525 + 1013904223; +} + +#endif |