/*
   * 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 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);

  extern int random_int_secret_init(void);

  #ifndef MODULE

  extern const struct file_operations random_fops, urandom_fops;

  #endif
  
  unsigned int get_random_int(void);

  unsigned long get_random_long(void);

  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 */