Linux kernel mirror (for testing)
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1/*
2 * include/linux/random.h
3 *
4 * Include file for the random number generator.
5 */
6#ifndef _LINUX_RANDOM_H
7#define _LINUX_RANDOM_H
8
9#include <linux/list.h>
10#include <linux/once.h>
11
12#include <uapi/linux/random.h>
13
14struct random_ready_callback {
15 struct list_head list;
16 void (*func)(struct random_ready_callback *rdy);
17 struct module *owner;
18};
19
20extern void add_device_randomness(const void *, unsigned int);
21
22#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
23static inline void add_latent_entropy(void)
24{
25 add_device_randomness((const void *)&latent_entropy,
26 sizeof(latent_entropy));
27}
28#else
29static inline void add_latent_entropy(void) {}
30#endif
31
32extern void add_input_randomness(unsigned int type, unsigned int code,
33 unsigned int value) __latent_entropy;
34extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
35
36extern void get_random_bytes(void *buf, int nbytes);
37extern int add_random_ready_callback(struct random_ready_callback *rdy);
38extern void del_random_ready_callback(struct random_ready_callback *rdy);
39extern void get_random_bytes_arch(void *buf, int nbytes);
40
41#ifndef MODULE
42extern const struct file_operations random_fops, urandom_fops;
43#endif
44
45u32 get_random_u32(void);
46u64 get_random_u64(void);
47static inline unsigned int get_random_int(void)
48{
49 return get_random_u32();
50}
51static inline unsigned long get_random_long(void)
52{
53#if BITS_PER_LONG == 64
54 return get_random_u64();
55#else
56 return get_random_u32();
57#endif
58}
59
60unsigned long randomize_page(unsigned long start, unsigned long range);
61
62u32 prandom_u32(void);
63void prandom_bytes(void *buf, size_t nbytes);
64void prandom_seed(u32 seed);
65void prandom_reseed_late(void);
66
67struct rnd_state {
68 __u32 s1, s2, s3, s4;
69};
70
71u32 prandom_u32_state(struct rnd_state *state);
72void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
73void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
74
75#define prandom_init_once(pcpu_state) \
76 DO_ONCE(prandom_seed_full_state, (pcpu_state))
77
78/**
79 * prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
80 * @ep_ro: right open interval endpoint
81 *
82 * Returns a pseudo-random number that is in interval [0, ep_ro). Note
83 * that the result depends on PRNG being well distributed in [0, ~0U]
84 * u32 space. Here we use maximally equidistributed combined Tausworthe
85 * generator, that is, prandom_u32(). This is useful when requesting a
86 * random index of an array containing ep_ro elements, for example.
87 *
88 * Returns: pseudo-random number in interval [0, ep_ro)
89 */
90static inline u32 prandom_u32_max(u32 ep_ro)
91{
92 return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
93}
94
95/*
96 * Handle minimum values for seeds
97 */
98static inline u32 __seed(u32 x, u32 m)
99{
100 return (x < m) ? x + m : x;
101}
102
103/**
104 * prandom_seed_state - set seed for prandom_u32_state().
105 * @state: pointer to state structure to receive the seed.
106 * @seed: arbitrary 64-bit value to use as a seed.
107 */
108static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
109{
110 u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
111
112 state->s1 = __seed(i, 2U);
113 state->s2 = __seed(i, 8U);
114 state->s3 = __seed(i, 16U);
115 state->s4 = __seed(i, 128U);
116}
117
118#ifdef CONFIG_ARCH_RANDOM
119# include <asm/archrandom.h>
120#else
121static inline bool arch_get_random_long(unsigned long *v)
122{
123 return 0;
124}
125static inline bool arch_get_random_int(unsigned int *v)
126{
127 return 0;
128}
129static inline bool arch_has_random(void)
130{
131 return 0;
132}
133static inline bool arch_get_random_seed_long(unsigned long *v)
134{
135 return 0;
136}
137static inline bool arch_get_random_seed_int(unsigned int *v)
138{
139 return 0;
140}
141static inline bool arch_has_random_seed(void)
142{
143 return 0;
144}
145#endif
146
147/* Pseudo random number generator from numerical recipes. */
148static inline u32 next_pseudo_random32(u32 seed)
149{
150 return seed * 1664525 + 1013904223;
151}
152
153#endif /* _LINUX_RANDOM_H */