| 1 |
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| 2 | |
| 3 | * This file is part of the Linux kernel.
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| 4 | *
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| 5 | * Copyright (c) 2011-2014, Intel Corporation
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| 6 | * Authors: Fenghua Yu <[email protected]>,
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| 7 | * H. Peter Anvin <[email protected]>
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| 8 |
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| 9 |
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| 10 | #ifndef ASM_X86_ARCHRANDOM_H
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| 11 | #define ASM_X86_ARCHRANDOM_H
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| 12 |
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| 13 | #include <asm/processor.h>
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| 14 | #include <asm/cpufeature.h>
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| 15 |
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| 16 | #define RDRAND_RETRY_LOOPS 10
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| 17 |
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| 18 |
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| 19 |
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| 20 | static inline bool __must_check rdrand_long(unsigned long *v)
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| 21 | {
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| 22 | bool ok;
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| 23 | unsigned int retry = RDRAND_RETRY_LOOPS;
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| 24 | do {
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| 25 | asm volatile("rdrand %[out]"
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| 26 | : "=@ccc" (ok), [out] "=r" (*v));
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| 27 | if (ok)
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| 28 | return true;
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| 29 | } while (--retry);
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| 30 | return false;
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| 31 | }
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| 32 |
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| 33 | static inline bool __must_check rdseed_long(unsigned long *v)
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| 34 | {
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| 35 | bool ok;
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| 36 | asm volatile("rdseed %[out]"
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| 37 | : "=@ccc" (ok), [out] "=r" (*v));
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| 38 | return ok;
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| 39 | }
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| 40 |
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| 41 | |
| 42 | * These are the generic interfaces; they must not be declared if the
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| 43 | * stubs in <linux/random.h> are to be invoked.
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| 44 |
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| 45 |
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| 46 | static inline size_t __must_check arch_get_random_longs(unsigned long *v, size_t max_longs)
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| 47 | {
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| 48 | return max_longs && cpu_feature_enabled(X86_FEATURE_RDRAND) && rdrand_long(v) ? 1 : 0;
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| 49 | }
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| 50 |
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| 51 | static inline size_t __must_check arch_get_random_seed_longs(unsigned long *v, size_t max_longs)
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| 52 | {
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| 53 | return max_longs && cpu_feature_enabled(X86_FEATURE_RDSEED) && rdseed_long(v) ? 1 : 0;
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| 54 | }
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| 55 |
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| 56 | #ifndef CONFIG_UML
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| 57 | void x86_init_rdrand(struct cpuinfo_x86 *c);
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| 58 | #endif
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| 59 |
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| 60 | #endif
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