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linux-headers-6.8.0-101
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random.h
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/* 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 <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, bool sleep_after); 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); } 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); int execute_with_initialized_rng(struct notifier_block *nb); /* 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> #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 */