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/* SPDX-License-Identifier: GPL-2.0 */
/*
* include/linux/random.h
*
* Include file for the random number generator.
*/
#ifndef _LINUX_RANDOM_H
#define _LINUX_RANDOM_H
#include <linux/list.h>
#include <linux/once.h>
#include <uapi/linux/random.h>
struct random_ready_callback {
struct list_head list;
void (*func)(struct random_ready_callback *rdy);
struct module *owner;
};
extern void add_device_randomness(const void *, unsigned int);
#if defined(CONFIG_GCC_PLUGIN_LATENT_ENTROPY) && !defined(__CHECKER__)
static inline void add_latent_entropy(void)
{
add_device_randomness((const void *)&latent_entropy,
sizeof(latent_entropy));
}
#else
static inline void add_latent_entropy(void) {}
#endif
extern void add_input_randomness(unsigned int type, unsigned int code,
unsigned int value) __latent_entropy;
extern void add_interrupt_randomness(int irq, int irq_flags) __latent_entropy;
extern void get_random_bytes(void *buf, int nbytes);
extern int wait_for_random_bytes(void);
extern int add_random_ready_callback(struct random_ready_callback *rdy);
extern void del_random_ready_callback(struct random_ready_callback *rdy);
extern void get_random_bytes_arch(void *buf, int nbytes);
#ifndef MODULE
extern const struct file_operations random_fops, urandom_fops;
#endif
u32 get_random_u32(void);
u64 get_random_u64(void);
static inline unsigned int get_random_int(void)
{
return get_random_u32();
}
static inline unsigned long get_random_long(void)
{
#if BITS_PER_LONG == 64
return get_random_u64();
#else
return get_random_u32();
#endif
}
/*
* On 64-bit architectures, protect against non-terminated C string overflows
* by zeroing out the first byte of the canary; this leaves 56 bits of entropy.
*/
#ifdef CONFIG_64BIT
# ifdef __LITTLE_ENDIAN
# define CANARY_MASK 0xffffffffffffff00UL
# else /* big endian, 64 bits: */
# define CANARY_MASK 0x00ffffffffffffffUL
# endif
#else /* 32 bits: */
# define CANARY_MASK 0xffffffffUL
#endif
static inline unsigned long get_random_canary(void)
{
unsigned long val = get_random_long();
return val & CANARY_MASK;
}
/* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes).
* Returns the result of the call to wait_for_random_bytes. */
static inline int get_random_bytes_wait(void *buf, int nbytes)
{
int ret = wait_for_random_bytes();
if (unlikely(ret))
return ret;
get_random_bytes(buf, nbytes);
return 0;
}
#define declare_get_random_var_wait(var) \
static inline int get_random_ ## var ## _wait(var *out) { \
int ret = wait_for_random_bytes(); \
if (unlikely(ret)) \
return ret; \
*out = get_random_ ## var(); \
return 0; \
}
declare_get_random_var_wait(u32)
declare_get_random_var_wait(u64)
declare_get_random_var_wait(int)
declare_get_random_var_wait(long)
#undef declare_get_random_var
unsigned long randomize_page(unsigned long start, unsigned long range);
u32 prandom_u32(void);
void prandom_bytes(void *buf, size_t nbytes);
void prandom_seed(u32 seed);
void prandom_reseed_late(void);
struct rnd_state {
__u32 s1, s2, s3, s4;
};
u32 prandom_u32_state(struct rnd_state *state);
void prandom_bytes_state(struct rnd_state *state, void *buf, size_t nbytes);
void prandom_seed_full_state(struct rnd_state __percpu *pcpu_state);
#define prandom_init_once(pcpu_state) \
DO_ONCE(prandom_seed_full_state, (pcpu_state))
/**
* prandom_u32_max - returns a pseudo-random number in interval [0, ep_ro)
* @ep_ro: right open interval endpoint
*
* Returns a pseudo-random number that is in interval [0, ep_ro). Note
* that the result depends on PRNG being well distributed in [0, ~0U]
* u32 space. Here we use maximally equidistributed combined Tausworthe
* generator, that is, prandom_u32(). This is useful when requesting a
* random index of an array containing ep_ro elements, for example.
*
* Returns: pseudo-random number in interval [0, ep_ro)
*/
static inline u32 prandom_u32_max(u32 ep_ro)
{
return (u32)(((u64) prandom_u32() * ep_ro) >> 32);
}
/*
* Handle minimum values for seeds
*/
static inline u32 __seed(u32 x, u32 m)
{
return (x < m) ? x + m : x;
}
/**
* prandom_seed_state - set seed for prandom_u32_state().
* @state: pointer to state structure to receive the seed.
* @seed: arbitrary 64-bit value to use as a seed.
*/
static inline void prandom_seed_state(struct rnd_state *state, u64 seed)
{
u32 i = (seed >> 32) ^ (seed << 10) ^ seed;
state->s1 = __seed(i, 2U);
state->s2 = __seed(i, 8U);
state->s3 = __seed(i, 16U);
state->s4 = __seed(i, 128U);
}
#ifdef CONFIG_ARCH_RANDOM
# include <asm/archrandom.h>
#else
static inline bool arch_get_random_long(unsigned long *v)
{
return 0;
}
static inline bool arch_get_random_int(unsigned int *v)
{
return 0;
}
static inline bool arch_has_random(void)
{
return 0;
}
static inline bool arch_get_random_seed_long(unsigned long *v)
{
return 0;
}
static inline bool arch_get_random_seed_int(unsigned int *v)
{
return 0;
}
static inline bool arch_has_random_seed(void)
{
return 0;
}
#endif
/* Pseudo random number generator from numerical recipes. */
static inline u32 next_pseudo_random32(u32 seed)
{
return seed * 1664525 + 1013904223;
}
#endif /* _LINUX_RANDOM_H */
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