Warning: That file was not part of the compilation database. It may have many parsing errors.
| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
|---|---|
| 2 | #ifndef __TOOLS_LINUX_PRANDOM_H |
| 3 | #define __TOOLS_LINUX_PRANDOM_H |
| 4 | |
| 5 | #include <linux/types.h> |
| 6 | |
| 7 | struct rnd_state { |
| 8 | __u32 s1, s2, s3, s4; |
| 9 | }; |
| 10 | |
| 11 | /* |
| 12 | * Handle minimum values for seeds |
| 13 | */ |
| 14 | static inline u32 __seed(u32 x, u32 m) |
| 15 | { |
| 16 | return (x < m) ? x + m : x; |
| 17 | } |
| 18 | |
| 19 | /** |
| 20 | * prandom_seed_state - set seed for prandom_u32_state(). |
| 21 | * @state: pointer to state structure to receive the seed. |
| 22 | * @seed: arbitrary 64-bit value to use as a seed. |
| 23 | */ |
| 24 | static inline void prandom_seed_state(struct rnd_state *state, u64 seed) |
| 25 | { |
| 26 | u32 i = ((seed >> 32) ^ (seed << 10) ^ seed) & 0xffffffffUL; |
| 27 | |
| 28 | state->s1 = __seed(i, 2U); |
| 29 | state->s2 = __seed(i, 8U); |
| 30 | state->s3 = __seed(i, 16U); |
| 31 | state->s4 = __seed(i, 128U); |
| 32 | } |
| 33 | |
| 34 | /** |
| 35 | * prandom_u32_state - seeded pseudo-random number generator. |
| 36 | * @state: pointer to state structure holding seeded state. |
| 37 | * |
| 38 | * This is used for pseudo-randomness with no outside seeding. |
| 39 | * For more random results, use get_random_u32(). |
| 40 | */ |
| 41 | static inline u32 prandom_u32_state(struct rnd_state *state) |
| 42 | { |
| 43 | #define TAUSWORTHE(s, a, b, c, d) (((s & c) << d) ^ (((s << a) ^ s) >> b)) |
| 44 | state->s1 = TAUSWORTHE(state->s1, 6U, 13U, 4294967294U, 18U); |
| 45 | state->s2 = TAUSWORTHE(state->s2, 2U, 27U, 4294967288U, 2U); |
| 46 | state->s3 = TAUSWORTHE(state->s3, 13U, 21U, 4294967280U, 7U); |
| 47 | state->s4 = TAUSWORTHE(state->s4, 3U, 12U, 4294967168U, 13U); |
| 48 | |
| 49 | return (state->s1 ^ state->s2 ^ state->s3 ^ state->s4); |
| 50 | } |
| 51 | #endif // __TOOLS_LINUX_PRANDOM_H |
| 52 |
Warning: That file was not part of the compilation database. It may have many parsing errors.