1 /* SPDX-License-Identifier: GPL-2.0 */ 2 3 #ifndef _LINUX_RANDOM_H 4 #define _LINUX_RANDOM_H 5 6 #include <linux/bug.h> 7 #include <linux/kernel.h> 8 #include <linux/list.h> 9 #include <linux/once.h> 10 11 #include <uapi/linux/random.h> 12 13 struct notifier_block; 14 15 void add_device_randomness(const void *buf, size_t len); 16 void add_bootloader_randomness(const void *buf, size_t len); 17 void add_input_randomness(unsigned int type, unsigned int code, 18 unsigned int value) __latent_entropy; 19 void add_interrupt_randomness(int irq) __latent_entropy; 20 void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy); 21 22 #if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__) 23 static inline void add_latent_entropy(void) 24 { 25 add_device_randomness((const void *)&latent_entropy, sizeof(latent_entropy)); 26 } 27 #else 28 static inline void add_latent_entropy(void) { } 29 #endif 30 31 #if IS_ENABLED(CONFIG_VMGENID) 32 void add_vmfork_randomness(const void *unique_vm_id, size_t len); 33 int register_random_vmfork_notifier(struct notifier_block *nb); 34 int unregister_random_vmfork_notifier(struct notifier_block *nb); 35 #else 36 static inline int register_random_vmfork_notifier(struct notifier_block *nb) { return 0; } 37 static inline int unregister_random_vmfork_notifier(struct notifier_block *nb) { return 0; } 38 #endif 39 40 void get_random_bytes(void *buf, size_t len); 41 u32 get_random_u32(void); 42 u64 get_random_u64(void); 43 static inline unsigned int get_random_int(void) 44 { 45 return get_random_u32(); 46 } 47 static inline unsigned long get_random_long(void) 48 { 49 #if BITS_PER_LONG == 64 50 return get_random_u64(); 51 #else 52 return get_random_u32(); 53 #endif 54 } 55 56 /* 57 * On 64-bit architectures, protect against non-terminated C string overflows 58 * by zeroing out the first byte of the canary; this leaves 56 bits of entropy. 59 */ 60 #ifdef CONFIG_64BIT 61 # ifdef __LITTLE_ENDIAN 62 # define CANARY_MASK 0xffffffffffffff00UL 63 # else /* big endian, 64 bits: */ 64 # define CANARY_MASK 0x00ffffffffffffffUL 65 # endif 66 #else /* 32 bits: */ 67 # define CANARY_MASK 0xffffffffUL 68 #endif 69 70 static inline unsigned long get_random_canary(void) 71 { 72 return get_random_long() & CANARY_MASK; 73 } 74 75 unsigned long randomize_page(unsigned long start, unsigned long range); 76 77 int __init random_init(const char *command_line); 78 bool rng_is_initialized(void); 79 bool rng_has_arch_random(void); 80 int wait_for_random_bytes(void); 81 82 /* Calls wait_for_random_bytes() and then calls get_random_bytes(buf, nbytes). 83 * Returns the result of the call to wait_for_random_bytes. */ 84 static inline int get_random_bytes_wait(void *buf, size_t nbytes) 85 { 86 int ret = wait_for_random_bytes(); 87 get_random_bytes(buf, nbytes); 88 return ret; 89 } 90 91 #define declare_get_random_var_wait(name, ret_type) \ 92 static inline int get_random_ ## name ## _wait(ret_type *out) { \ 93 int ret = wait_for_random_bytes(); \ 94 if (unlikely(ret)) \ 95 return ret; \ 96 *out = get_random_ ## name(); \ 97 return 0; \ 98 } 99 declare_get_random_var_wait(u32, u32) 100 declare_get_random_var_wait(u64, u32) 101 declare_get_random_var_wait(int, unsigned int) 102 declare_get_random_var_wait(long, unsigned long) 103 #undef declare_get_random_var 104 105 /* 106 * This is designed to be standalone for just prandom 107 * users, but for now we include it from <linux/random.h> 108 * for legacy reasons. 109 */ 110 #include <linux/prandom.h> 111 112 #ifdef CONFIG_ARCH_RANDOM 113 # include <asm/archrandom.h> 114 #else 115 static inline bool __must_check arch_get_random_long(unsigned long *v) { return false; } 116 static inline bool __must_check arch_get_random_int(unsigned int *v) { return false; } 117 static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return false; } 118 static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return false; } 119 #endif 120 121 /* 122 * Called from the boot CPU during startup; not valid to call once 123 * secondary CPUs are up and preemption is possible. 124 */ 125 #ifndef arch_get_random_seed_long_early 126 static inline bool __init arch_get_random_seed_long_early(unsigned long *v) 127 { 128 WARN_ON(system_state != SYSTEM_BOOTING); 129 return arch_get_random_seed_long(v); 130 } 131 #endif 132 133 #ifndef arch_get_random_long_early 134 static inline bool __init arch_get_random_long_early(unsigned long *v) 135 { 136 WARN_ON(system_state != SYSTEM_BOOTING); 137 return arch_get_random_long(v); 138 } 139 #endif 140 141 #ifdef CONFIG_SMP 142 int random_prepare_cpu(unsigned int cpu); 143 int random_online_cpu(unsigned int cpu); 144 #endif 145 146 #ifndef MODULE 147 extern const struct file_operations random_fops, urandom_fops; 148 #endif 149 150 #endif /* _LINUX_RANDOM_H */ 151