1 /* SPDX-License-Identifier: GPL-2.0 */
3 * include/linux/random.h
5 * Include file for the random number generator.
7 #ifndef _LINUX_RANDOM_H
8 #define _LINUX_RANDOM_H
10 #include <linux/list.h>
11 #include <linux/once.h>
13 #include <uapi/linux/random.h>
15 struct random_ready_callback {
16 struct list_head list;
17 void (*func)(struct random_ready_callback *rdy);
21 extern void add_device_randomness(const void *, unsigned int);
23 #if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
24 static inline void add_latent_entropy(void)
26 add_device_randomness((const void *)&latent_entropy,
27 sizeof(latent_entropy));
30 static inline void add_latent_entropy(void) {}
33 extern void add_input_randomness(unsigned int type, unsigned int code,
34 unsigned int value) __latent_entropy;
35 extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
37 extern void get_random_bytes(void *buf, int nbytes);
38 extern int wait_for_random_bytes(void);
39 extern int add_random_ready_callback(struct random_ready_callback *rdy);
40 extern void del_random_ready_callback(struct random_ready_callback *rdy);
41 extern void get_random_bytes_arch(void *buf, int nbytes);
44 extern const struct file_operations random_fops, urandom_fops;
47 u32 get_random_u32(void);
48 u64 get_random_u64(void);
49 static inline unsigned int get_random_int(void)
51 return get_random_u32();
53 static inline unsigned long get_random_long(void)
55 #if BITS_PER_LONG == 64
56 return get_random_u64();
58 return get_random_u32();
63 * On 64-bit architectures, protect against non-terminated C string overflows
64 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
67 # ifdef __LITTLE_ENDIAN
68 # define CANARY_MASK 0xffffffffffffff00UL
69 # else /* big endian, 64 bits: */
70 # define CANARY_MASK 0x00ffffffffffffffUL
73 # define CANARY_MASK 0xffffffffUL
76 static inline unsigned long get_random_canary(void)
78 unsigned long val = get_random_long();
80 return val & CANARY_MASK;
83 /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
84 * Returns the result of the call to wait_for_random_bytes. */
85 static inline int get_random_bytes_wait(void *buf, int nbytes)
87 int ret = wait_for_random_bytes();
90 get_random_bytes(buf, nbytes);
94 #define declare_get_random_var_wait(var) \
95 static inline int get_random_ ## var ## _wait(var *out) { \
96 int ret = wait_for_random_bytes(); \
99 *out = get_random_ ## var(); \
102 declare_get_random_var_wait(u32)
103 declare_get_random_var_wait(u64)
104 declare_get_random_var_wait(int)
105 declare_get_random_var_wait(long)
106 #undef declare_get_random_var
108 unsigned long randomize_page(unsigned long start, unsigned long range);
111 * This is designed to be standalone for just prandom
112 * users, but for now we include it from <linux/random.h>
113 * for legacy reasons.
115 #include <linux/prandom.h>
117 #ifdef CONFIG_ARCH_RANDOM
118 # include <asm/archrandom.h>
120 static inline bool arch_get_random_long(unsigned long *v)
124 static inline bool arch_get_random_int(unsigned int *v)
128 static inline bool arch_has_random(void)
132 static inline bool arch_get_random_seed_long(unsigned long *v)
136 static inline bool arch_get_random_seed_int(unsigned int *v)
140 static inline bool arch_has_random_seed(void)
146 #endif /* _LINUX_RANDOM_H */