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 extern void add_device_randomness(const void *, size_t);
16 extern void add_bootloader_randomness(const void *, size_t);
18 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
19 static inline void add_latent_entropy(void)
21 add_device_randomness((const void *)&latent_entropy,
22 sizeof(latent_entropy));
25 static inline void add_latent_entropy(void) {}
28 extern void add_input_randomness(unsigned int type, unsigned int code,
29 unsigned int value) __latent_entropy;
30 extern void add_interrupt_randomness(int irq) __latent_entropy;
31 extern void add_hwgenerator_randomness(const void *buffer, size_t count,
33 #if IS_ENABLED(CONFIG_VMGENID)
34 extern void add_vmfork_randomness(const void *unique_vm_id, size_t size);
35 extern int register_random_vmfork_notifier(struct notifier_block *nb);
36 extern int unregister_random_vmfork_notifier(struct notifier_block *nb);
38 static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
39 static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
42 extern void get_random_bytes(void *buf, size_t nbytes);
43 extern int wait_for_random_bytes(void);
44 extern int __init rand_initialize(void);
45 extern bool rng_is_initialized(void);
46 extern int register_random_ready_notifier(struct notifier_block *nb);
47 extern int unregister_random_ready_notifier(struct notifier_block *nb);
48 extern size_t __must_check get_random_bytes_arch(void *buf, size_t nbytes);
51 extern const struct file_operations random_fops, urandom_fops;
54 u32 get_random_u32(void);
55 u64 get_random_u64(void);
56 static inline unsigned int get_random_int(void)
58 return get_random_u32();
60 static inline unsigned long get_random_long(void)
62 #if BITS_PER_LONG == 64
63 return get_random_u64();
65 return get_random_u32();
70 * On 64-bit architectures, protect against non-terminated C string overflows
71 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
74 # ifdef __LITTLE_ENDIAN
75 # define CANARY_MASK 0xffffffffffffff00UL
76 # else /* big endian, 64 bits: */
77 # define CANARY_MASK 0x00ffffffffffffffUL
80 # define CANARY_MASK 0xffffffffUL
83 static inline unsigned long get_random_canary(void)
85 unsigned long val = get_random_long();
87 return val & CANARY_MASK;
90 /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
91 * Returns the result of the call to wait_for_random_bytes. */
92 static inline int get_random_bytes_wait(void *buf, size_t nbytes)
94 int ret = wait_for_random_bytes();
95 get_random_bytes(buf, nbytes);
99 #define declare_get_random_var_wait(var) \
100 static inline int get_random_ ## var ## _wait(var *out) { \
101 int ret = wait_for_random_bytes(); \
104 *out = get_random_ ## var(); \
107 declare_get_random_var_wait(u32)
108 declare_get_random_var_wait(u64)
109 declare_get_random_var_wait(int)
110 declare_get_random_var_wait(long)
111 #undef declare_get_random_var
113 unsigned long randomize_page(unsigned long start, unsigned long range);
116 * This is designed to be standalone for just prandom
117 * users, but for now we include it from <linux/random.h>
118 * for legacy reasons.
120 #include <linux/prandom.h>
122 #ifdef CONFIG_ARCH_RANDOM
123 # include <asm/archrandom.h>
125 static inline bool __must_check arch_get_random_long(unsigned long *v)
129 static inline bool __must_check arch_get_random_int(unsigned int *v)
133 static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
137 static inline bool __must_check arch_get_random_seed_int(unsigned int *v)
144 * Called from the boot CPU during startup; not valid to call once
145 * secondary CPUs are up and preemption is possible.
147 #ifndef arch_get_random_seed_long_early
148 static inline bool __init arch_get_random_seed_long_early(unsigned long *v)
150 WARN_ON(system_state != SYSTEM_BOOTING);
151 return arch_get_random_seed_long(v);
155 #ifndef arch_get_random_long_early
156 static inline bool __init arch_get_random_long_early(unsigned long *v)
158 WARN_ON(system_state != SYSTEM_BOOTING);
159 return arch_get_random_long(v);
164 extern int random_prepare_cpu(unsigned int cpu);
165 extern int random_online_cpu(unsigned int cpu);
168 #endif /* _LINUX_RANDOM_H */