1 /* SPDX-License-Identifier: GPL-2.0 */
3 #ifndef _LINUX_RANDOM_H
4 #define _LINUX_RANDOM_H
7 #include <linux/kernel.h>
8 #include <linux/list.h>
9 #include <linux/once.h>
11 #include <uapi/linux/random.h>
13 struct notifier_block;
15 void add_device_randomness(const void *buf, size_t len);
16 void __init add_bootloader_randomness(const void *buf, size_t len);
17 void add_input_randomness(unsigned int type, unsigned int code,
18 unsigned int value) __latent_entropy;
19 void add_interrupt_randomness(int irq) __latent_entropy;
20 void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy);
22 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
23 static inline void add_latent_entropy(void)
25 add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy));
28 static inline void add_latent_entropy(void) { }
31 #if IS_ENABLED(CONFIG_VMGENID)
32 void add_vmfork_randomness(const void *unique_vm_id, size_t len);
33 int register_random_vmfork_notifier(struct notifier_block *nb);
34 int unregister_random_vmfork_notifier(struct notifier_block *nb);
36 static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
37 static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
40 void get_random_bytes(void *buf, size_t len);
41 u32 get_random_u32(void);
42 u64 get_random_u64(void);
43 static inline unsigned int get_random_int(void)
45 return get_random_u32();
47 static inline unsigned long get_random_long(void)
49 #if BITS_PER_LONG == 64
50 return get_random_u64();
52 return get_random_u32();
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.
61 # ifdef __LITTLE_ENDIAN
62 # define CANARY_MASK 0xffffffffffffff00UL
63 # else /* big endian, 64 bits: */
64 # define CANARY_MASK 0x00ffffffffffffffUL
67 # define CANARY_MASK 0xffffffffUL
70 static inline unsigned long get_random_canary(void)
72 return get_random_long() & CANARY_MASK;
75 int __init random_init(const char *command_line);
76 bool rng_is_initialized(void);
77 int wait_for_random_bytes(void);
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. */
81 static inline int get_random_bytes_wait(void *buf, size_t nbytes)
83 int ret = wait_for_random_bytes();
84 get_random_bytes(buf, nbytes);
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(); \
93 *out = get_random_ ## name(); \
96 declare_get_random_var_wait(u32, u32)
97 declare_get_random_var_wait(u64, u32)
98 declare_get_random_var_wait(int, unsigned int)
99 declare_get_random_var_wait(long, unsigned long)
100 #undef declare_get_random_var
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.
107 #include <linux/prandom.h>
109 #ifdef CONFIG_ARCH_RANDOM
110 # include <asm/archrandom.h>
112 static inline bool __must_check arch_get_random_long(unsigned long *v) { return false; }
113 static inline bool __must_check arch_get_random_int(unsigned int *v) { return false; }
114 static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return false; }
115 static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return false; }
119 * Called from the boot CPU during startup; not valid to call once
120 * secondary CPUs are up and preemption is possible.
122 #ifndef arch_get_random_seed_long_early
123 static inline bool __init arch_get_random_seed_long_early(unsigned long *v)
125 WARN_ON(system_state != SYSTEM_BOOTING);
126 return arch_get_random_seed_long(v);
130 #ifndef arch_get_random_long_early
131 static inline bool __init arch_get_random_long_early(unsigned long *v)
133 WARN_ON(system_state != SYSTEM_BOOTING);
134 return arch_get_random_long(v);
139 int random_prepare_cpu(unsigned int cpu);
140 int random_online_cpu(unsigned int cpu);
144 extern const struct file_operations random_fops, urandom_fops;
147 #endif /* _LINUX_RANDOM_H */