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 *, size_t);
16 void add_bootloader_randomness(const void *, size_t);
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 *buffer, size_t count, 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 size);
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 nbytes);
41 size_t __must_check get_random_bytes_arch(void *buf, size_t nbytes);
42 u32 get_random_u32(void);
43 u64 get_random_u64(void);
44 static inline unsigned int get_random_int(void)
46 return get_random_u32();
48 static inline unsigned long get_random_long(void)
50 #if BITS_PER_LONG == 64
51 return get_random_u64();
53 return get_random_u32();
58 * On 64-bit architectures, protect against non-terminated C string overflows
59 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
62 # ifdef __LITTLE_ENDIAN
63 # define CANARY_MASK 0xffffffffffffff00UL
64 # else /* big endian, 64 bits: */
65 # define CANARY_MASK 0x00ffffffffffffffUL
68 # define CANARY_MASK 0xffffffffUL
71 static inline unsigned long get_random_canary(void)
73 return get_random_long() & CANARY_MASK;
76 unsigned long randomize_page(unsigned long start, unsigned long range);
78 int __init random_init(const char *command_line);
79 bool rng_is_initialized(void);
80 int wait_for_random_bytes(void);
81 int register_random_ready_notifier(struct notifier_block *nb);
82 int unregister_random_ready_notifier(struct notifier_block *nb);
84 /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
85 * Returns the result of the call to wait_for_random_bytes. */
86 static inline int get_random_bytes_wait(void *buf, size_t nbytes)
88 int ret = wait_for_random_bytes();
89 get_random_bytes(buf, nbytes);
93 #define declare_get_random_var_wait(name, ret_type) \
94 static inline int get_random_ ## name ## _wait(ret_type *out) { \
95 int ret = wait_for_random_bytes(); \
98 *out = get_random_ ## name(); \
101 declare_get_random_var_wait(u32, u32)
102 declare_get_random_var_wait(u64, u32)
103 declare_get_random_var_wait(int, unsigned int)
104 declare_get_random_var_wait(long, unsigned long)
105 #undef declare_get_random_var
108 * This is designed to be standalone for just prandom
109 * users, but for now we include it from <linux/random.h>
110 * for legacy reasons.
112 #include <linux/prandom.h>
114 #ifdef CONFIG_ARCH_RANDOM
115 # include <asm/archrandom.h>
117 static inline bool __must_check arch_get_random_long(unsigned long *v) { return false; }
118 static inline bool __must_check arch_get_random_int(unsigned int *v) { return false; }
119 static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return false; }
120 static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return false; }
124 * Called from the boot CPU during startup; not valid to call once
125 * secondary CPUs are up and preemption is possible.
127 #ifndef arch_get_random_seed_long_early
128 static inline bool __init arch_get_random_seed_long_early(unsigned long *v)
130 WARN_ON(system_state != SYSTEM_BOOTING);
131 return arch_get_random_seed_long(v);
135 #ifndef arch_get_random_long_early
136 static inline bool __init arch_get_random_long_early(unsigned long *v)
138 WARN_ON(system_state != SYSTEM_BOOTING);
139 return arch_get_random_long(v);
144 int random_prepare_cpu(unsigned int cpu);
145 int random_online_cpu(unsigned int cpu);
149 extern const struct file_operations random_fops, urandom_fops;
152 #endif /* _LINUX_RANDOM_H */