v4.19.13 snapshot.
diff --git a/include/linux/random.h b/include/linux/random.h
new file mode 100644
index 0000000..445a0ea
--- /dev/null
+++ b/include/linux/random.h
@@ -0,0 +1,200 @@
+/* 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 bool rng_is_initialized(void);
+extern int add_random_ready_callback(struct random_ready_callback *rdy);
+extern void del_random_ready_callback(struct random_ready_callback *rdy);
+extern int __must_check 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();
+ get_random_bytes(buf, nbytes);
+ return ret;
+}
+
+#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 */