#include <linux/bug.h>
#include <linux/kernel.h>
#include <linux/list.h>
-#include <linux/once.h>
#include <uapi/linux/random.h>
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);
+void add_hwgenerator_randomness(const void *buf, size_t len, size_t entropy, bool sleep_after);
-#if defined(LATENT_ENTROPY_PLUGIN) && !defined(__CHECKER__)
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
-static inline void add_latent_entropy(void) { }
+ add_device_randomness(NULL, 0);
#endif
+}
#if IS_ENABLED(CONFIG_VMGENID)
void add_vmfork_randomness(const void *unique_vm_id, size_t len);
#endif
}
+u32 __get_random_u32_below(u32 ceil);
+
/*
- * 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.
+ * 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.
*/
-#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 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);
+}
-static inline unsigned long get_random_canary(void)
+/*
+ * 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)
{
- return get_random_long() & CANARY_MASK;
+ 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. */
#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);
projects / linux-2.6-microblaze.git / blobdiff