62 lines
1.4 KiB
C
62 lines
1.4 KiB
C
|
/* 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
|