1 files changed, 205 insertions, 0 deletions
diff --git a/include/linux/random.h b/include/linux/random.h
new file mode 100644
index 000000000..51133627b
--- /dev/null
+++ b/include/linux/random.h
@@ -0,0 +1,205 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#ifndef _LINUX_RANDOM_H
+#define _LINUX_RANDOM_H
+
+#include <linux/bug.h>
+#include <linux/kernel.h>
+#include <linux/list.h>
+#include <linux/once.h>
+
+#include <uapi/linux/random.h>
+
+struct notifier_block;
+
+void add_device_randomness(const void *buf, size_t len);
+void __init add_bootloader_randomness(const void *buf, size_t len);
+void add_input_randomness(unsigned int type, unsigned int code,
+			  unsigned int value) __latent_entropy;
+void add_interrupt_randomness(int irq) __latent_entropy;
+void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy);
+
+static inline void add_latent_entropy(void)
+{
+#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
+	add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy));
+#else
+	add_device_randomness(NULL, 0);
+#endif
+}
+
+#if IS_ENABLED(CONFIG_VMGENID)
+void add_vmfork_randomness(const void *unique_vm_id, size_t len);
+int register_random_vmfork_notifier(struct notifier_block *nb);
+int unregister_random_vmfork_notifier(struct notifier_block *nb);
+#else
+static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
+static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; }
+#endif
+
+void get_random_bytes(void *buf, size_t len);
+u8 get_random_u8(void);
+u16 get_random_u16(void);
+u32 get_random_u32(void);
+u64 get_random_u64(void);
+static inline unsigned long get_random_long(void)
+{
+#if BITS_PER_LONG == 64
+	return get_random_u64();
+#else
+	return get_random_u32();
+#endif
+}
+
+u32 __get_random_u32_below(u32 ceil);
+
+/*
+ * Returns a random integer in the interval [0, ceil), with uniform
+ * distribution, suitable for all uses. Fastest when ceil is a constant, but
+ * still fast for variable ceil as well.
+ */
+static inline u32 get_random_u32_below(u32 ceil)
+{
+	if (!__builtin_constant_p(ceil))
+		return __get_random_u32_below(ceil);
+
+	/*
+	 * For the fast path, below, all operations on ceil are precomputed by
+	 * the compiler, so this incurs no overhead for checking pow2, doing
+	 * divisions, or branching based on integer size. The resultant
+	 * algorithm does traditional reciprocal multiplication (typically
+	 * optimized by the compiler into shifts and adds), rejecting samples
+	 * whose lower half would indicate a range indivisible by ceil.
+	 */
+	BUILD_BUG_ON_MSG(!ceil, "get_random_u32_below() must take ceil > 0");
+	if (ceil <= 1)
+		return 0;
+	for (;;) {
+		if (ceil <= 1U << 8) {
+			u32 mult = ceil * get_random_u8();
+			if (likely(is_power_of_2(ceil) || (u8)mult >= (1U << 8) % ceil))
+				return mult >> 8;
+		} else if (ceil <= 1U << 16) {
+			u32 mult = ceil * get_random_u16();
+			if (likely(is_power_of_2(ceil) || (u16)mult >= (1U << 16) % ceil))
+				return mult >> 16;
+		} else {
+			u64 mult = (u64)ceil * get_random_u32();
+			if (likely(is_power_of_2(ceil) || (u32)mult >= -ceil % ceil))
+				return mult >> 32;
+		}
+	}
+}
+
+/*
+ * Returns a random integer in the interval (floor, U32_MAX], with uniform
+ * distribution, suitable for all uses. Fastest when floor is a constant, but
+ * still fast for variable floor as well.
+ */
+static inline u32 get_random_u32_above(u32 floor)
+{
+	BUILD_BUG_ON_MSG(__builtin_constant_p(floor) && floor == U32_MAX,
+			 "get_random_u32_above() must take floor < U32_MAX");
+	return floor + 1 + get_random_u32_below(U32_MAX - floor);
+}
+
+/*
+ * Returns a random integer in the interval [floor, ceil], with uniform
+ * distribution, suitable for all uses. Fastest when floor and ceil are
+ * constant, but still fast for variable floor and ceil as well.
+ */
+static inline u32 get_random_u32_inclusive(u32 floor, u32 ceil)
+{
+	BUILD_BUG_ON_MSG(__builtin_constant_p(floor) && __builtin_constant_p(ceil) &&
+			 (floor > ceil || ceil - floor == U32_MAX),
+			 "get_random_u32_inclusive() must take floor <= ceil");
+	return floor + get_random_u32_below(ceil - floor + 1);
+}
+
+/*
+ * 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)
+{
+	return get_random_long() & CANARY_MASK;
+}
+
+void __init random_init_early(const char *command_line);
+void __init random_init(void);
+bool rng_is_initialized(void);
+int wait_for_random_bytes(void);
+
+/* 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, size_t nbytes)
+{
+	int ret = wait_for_random_bytes();
+	get_random_bytes(buf, nbytes);
+	return ret;
+}
+
+#define declare_get_random_var_wait(name, ret_type) \
+	static inline int get_random_ ## name ## _wait(ret_type *out) { \
+		int ret = wait_for_random_bytes(); \
+		if (unlikely(ret)) \
+			return ret; \
+		*out = get_random_ ## name(); \
+		return 0; \
+	}
+declare_get_random_var_wait(u8, u8)
+declare_get_random_var_wait(u16, u16)
+declare_get_random_var_wait(u32, u32)
+declare_get_random_var_wait(u64, u32)
+declare_get_random_var_wait(long, unsigned long)
+#undef declare_get_random_var
+
+/*
+ * This is designed to be standalone for just prandom
+ * users, but for now we include it from <linux/random.h>
+ * for legacy reasons.
+ */
+#include <linux/prandom.h>
+
+#include <asm/archrandom.h>
+
+/*
+ * Called from the boot CPU during startup; not valid to call once
+ * secondary CPUs are up and preemption is possible.
+ */
+#ifndef arch_get_random_seed_longs_early
+static inline size_t __init arch_get_random_seed_longs_early(unsigned long *v, size_t max_longs)
+{
+	WARN_ON(system_state != SYSTEM_BOOTING);
+	return arch_get_random_seed_longs(v, max_longs);
+}
+#endif
+
+#ifndef arch_get_random_longs_early
+static inline bool __init arch_get_random_longs_early(unsigned long *v, size_t max_longs)
+{
+	WARN_ON(system_state != SYSTEM_BOOTING);
+	return arch_get_random_longs(v, max_longs);
+}
+#endif
+
+#ifdef CONFIG_SMP
+int random_prepare_cpu(unsigned int cpu);
+int random_online_cpu(unsigned int cpu);
+#endif
+
+#ifndef MODULE
+extern const struct file_operations random_fops, urandom_fops;
+#endif
+
+#endif /* _LINUX_RANDOM_H */