1/* SPDX-License-Identifier: GPL-2.0 */
2
3#ifndef _LINUX_RANDOM_H
4#define _LINUX_RANDOM_H
5
6#include <linux/bug.h>
7#include <linux/kernel.h>
8#include <linux/list.h>
9#include <linux/once.h>
10
11#include <uapi/linux/random.h>
12
13struct notifier_block;
14
15void add_device_randomness(const void *buf, size_t len);
16void __init add_bootloader_randomness(const void *buf, size_t len);
17void add_input_randomness(unsigned int type, unsigned int code,
18 unsigned int value) __latent_entropy;
19void add_interrupt_randomness(int irq) __latent_entropy;
20void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy);
21
22#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
23static inline void add_latent_entropy(void)
24{
25 add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy));
26}
27#else
28static inline void add_latent_entropy(void) { }
29#endif
30
31#if IS_ENABLED(CONFIG_VMGENID)
32void add_vmfork_randomness(const void *unique_vm_id, size_t len);
33int register_random_vmfork_notifier(struct notifier_block *nb);
34int unregister_random_vmfork_notifier(struct notifier_block *nb);
35#else
36static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
37static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
38#endif
39
40void get_random_bytes(void *buf, size_t len);
41u32 get_random_u32(void);
42u64 get_random_u64(void);
43static inline unsigned int get_random_int(void)
44{
45 return get_random_u32();
46}
47static inline unsigned long get_random_long(void)
48{
49#if BITS_PER_LONG == 64
50 return get_random_u64();
51#else
52 return get_random_u32();
53#endif
54}
55
56/*
57 * On 64-bit architectures, protect against non-terminated C string overflows
58 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
59 */
60#ifdef CONFIG_64BIT
61# ifdef __LITTLE_ENDIAN
62# define CANARY_MASK 0xffffffffffffff00UL
63# else /* big endian, 64 bits: */
64# define CANARY_MASK 0x00ffffffffffffffUL
65# endif
66#else /* 32 bits: */
67# define CANARY_MASK 0xffffffffUL
68#endif
69
70static inline unsigned long get_random_canary(void)
71{
72 return get_random_long() & CANARY_MASK;
73}
74
75int __init random_init(const char *command_line);
76bool rng_is_initialized(void);
77int wait_for_random_bytes(void);
78
79/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
80 * Returns the result of the call to wait_for_random_bytes. */
81static inline int get_random_bytes_wait(void *buf, size_t nbytes)
82{
83 int ret = wait_for_random_bytes();
84 get_random_bytes(buf, nbytes);
85 return ret;
86}
87
88#define declare_get_random_var_wait(name, ret_type) \
89 static inline int get_random_ ## name ## _wait(ret_type *out) { \
90 int ret = wait_for_random_bytes(); \
91 if (unlikely(ret)) \
92 return ret; \
93 *out = get_random_ ## name(); \
94 return 0; \
95 }
96declare_get_random_var_wait(u32, u32)
97declare_get_random_var_wait(u64, u32)
98declare_get_random_var_wait(int, unsigned int)
99declare_get_random_var_wait(long, unsigned long)
100#undef declare_get_random_var
101
102/*
103 * This is designed to be standalone for just prandom
104 * users, but for now we include it from <linux/random.h>
105 * for legacy reasons.
106 */
107#include <linux/prandom.h>
108
109#include <asm/archrandom.h>
110
111/*
112 * Called from the boot CPU during startup; not valid to call once
113 * secondary CPUs are up and preemption is possible.
114 */
115#ifndef arch_get_random_seed_longs_early
116static inline size_t __init arch_get_random_seed_longs_early(unsigned long *v, size_t max_longs)
117{
118 WARN_ON(system_state != SYSTEM_BOOTING);
119 return arch_get_random_seed_longs(v, max_longs);
120}
121#endif
122
123#ifndef arch_get_random_longs_early
124static inline bool __init arch_get_random_longs_early(unsigned long *v, size_t max_longs)
125{
126 WARN_ON(system_state != SYSTEM_BOOTING);
127 return arch_get_random_longs(v, max_longs);
128}
129#endif
130
131#ifdef CONFIG_SMP
132int random_prepare_cpu(unsigned int cpu);
133int random_online_cpu(unsigned int cpu);
134#endif
135
136#ifndef MODULE
137extern const struct file_operations random_fops, urandom_fops;
138#endif
139
140#endif /* _LINUX_RANDOM_H */
141

source code of linux/include/linux/random.h