projects / mirror_ubuntu-artful-kernel.git / blame
| Commit | Line | Data |
|---|---|---|
| 628c6246 PA |
1 | /* |
| 2 | * This file is part of the Linux kernel. | |
| 3 | * | |
| d20f78d2 | 4 | * Copyright (c) 2011-2014, Intel Corporation |
| 628c6246 PA |
5 | * Authors: Fenghua Yu <fenghua.yu@intel.com>, |
| 6 | * H. Peter Anvin <hpa@linux.intel.com> | |
| 7 | * | |
| 8 | * This program is free software; you can redistribute it and/or modify it | |
| 9 | * under the terms and conditions of the GNU General Public License, | |
| 10 | * version 2, as published by the Free Software Foundation. | |
| 11 | * | |
| 12 | * This program is distributed in the hope it will be useful, but WITHOUT | |
| 13 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 14 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
| 15 | * more details. | |
| 16 | * | |
| 17 | * You should have received a copy of the GNU General Public License along with | |
| 18 | * this program; if not, write to the Free Software Foundation, Inc., | |
| 19 | * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. | |
| 20 | * | |
| 21 | */ | |
| 22 | ||
| 23 | #ifndef ASM_X86_ARCHRANDOM_H | |
| 24 | #define ASM_X86_ARCHRANDOM_H | |
| 25 | ||
| 26 | #include <asm/processor.h> | |
| 27 | #include <asm/cpufeature.h> | |
| 628c6246 PA |
28 | |
| 29 | #define RDRAND_RETRY_LOOPS 10 | |
| 30 | ||
| 31 | #define RDRAND_INT ".byte 0x0f,0xc7,0xf0" | |
| d20f78d2 | 32 | #define RDSEED_INT ".byte 0x0f,0xc7,0xf8" |
| 628c6246 PA |
33 | #ifdef CONFIG_X86_64 |
| 34 | # define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0" | |
| d20f78d2 | 35 | # define RDSEED_LONG ".byte 0x48,0x0f,0xc7,0xf8" |
| 628c6246 PA |
36 | #else |
| 37 | # define RDRAND_LONG RDRAND_INT | |
| d20f78d2 | 38 | # define RDSEED_LONG RDSEED_INT |
| 628c6246 PA |
39 | #endif |
| 40 | ||
| 3b290398 | 41 | /* Unconditional execution of RDRAND and RDSEED */ |
| 628c6246 | 42 | |
| 117780ee | 43 | static inline bool rdrand_long(unsigned long *v) |
| 5bfce5ef | 44 | { |
| 3b290398 PA |
45 | bool ok; |
| 46 | unsigned int retry = RDRAND_RETRY_LOOPS; | |
| 47 | do { | |
| 1c3f29ec | 48 | asm volatile(RDRAND_LONG |
| 3b290398 PA |
49 | CC_SET(c) |
| 50 | : CC_OUT(c) (ok), "=a" (*v)); | |
| 51 | if (ok) | |
| 52 | return true; | |
| 53 | } while (--retry); | |
| 54 | return false; | |
| 55 | } | |
| 56 | ||
| 57 | static inline bool rdrand_int(unsigned int *v) | |
| 58 | { | |
| 59 | bool ok; | |
| 60 | unsigned int retry = RDRAND_RETRY_LOOPS; | |
| 61 | do { | |
| 1c3f29ec | 62 | asm volatile(RDRAND_INT |
| 3b290398 PA |
63 | CC_SET(c) |
| 64 | : CC_OUT(c) (ok), "=a" (*v)); | |
| 65 | if (ok) | |
| 66 | return true; | |
| 67 | } while (--retry); | |
| 68 | return false; | |
| 5bfce5ef KC |
69 | } |
| 70 | ||
| d20f78d2 PA |
71 | static inline bool rdseed_long(unsigned long *v) |
| 72 | { | |
| 117780ee | 73 | bool ok; |
| 1c3f29ec | 74 | asm volatile(RDSEED_LONG |
| 3b290398 PA |
75 | CC_SET(c) |
| 76 | : CC_OUT(c) (ok), "=a" (*v)); | |
| d20f78d2 PA |
77 | return ok; |
| 78 | } | |
| 79 | ||
| 3b290398 PA |
80 | static inline bool rdseed_int(unsigned int *v) |
| 81 | { | |
| 82 | bool ok; | |
| 1c3f29ec | 83 | asm volatile(RDSEED_INT |
| 3b290398 PA |
84 | CC_SET(c) |
| 85 | : CC_OUT(c) (ok), "=a" (*v)); | |
| 86 | return ok; | |
| d20f78d2 PA |
87 | } |
| 88 | ||
| 3b290398 | 89 | /* Conditional execution based on CPU type */ |
| 7b878d4b PA |
90 | #define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND) |
| 91 | #define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED) | |
| 92 | ||
| 3b290398 PA |
93 | /* |
| 94 | * These are the generic interfaces; they must not be declared if the | |
| 95 | * stubs in <linux/random.h> are to be invoked, | |
| 96 | * i.e. CONFIG_ARCH_RANDOM is not defined. | |
| 97 | */ | |
| 98 | #ifdef CONFIG_ARCH_RANDOM | |
| 5bfce5ef | 99 | |
| 3b290398 | 100 | static inline bool arch_get_random_long(unsigned long *v) |
| 5bfce5ef | 101 | { |
| 3b290398 | 102 | return arch_has_random() ? rdrand_long(v) : false; |
| 5bfce5ef KC |
103 | } |
| 104 | ||
| 3b290398 | 105 | static inline bool arch_get_random_int(unsigned int *v) |
| d20f78d2 | 106 | { |
| 3b290398 | 107 | return arch_has_random() ? rdrand_int(v) : false; |
| d20f78d2 PA |
108 | } |
| 109 | ||
| 3b290398 PA |
110 | static inline bool arch_get_random_seed_long(unsigned long *v) |
| 111 | { | |
| 112 | return arch_has_random_seed() ? rdseed_long(v) : false; | |
| 113 | } | |
| 114 | ||
| 115 | static inline bool arch_get_random_seed_int(unsigned int *v) | |
| 116 | { | |
| 117 | return arch_has_random_seed() ? rdseed_int(v) : false; | |
| 118 | } | |
| 628c6246 | 119 | |
| 49d859d7 PA |
120 | extern void x86_init_rdrand(struct cpuinfo_x86 *c); |
| 121 | ||
| 3b290398 PA |
122 | #else /* !CONFIG_ARCH_RANDOM */ |
| 123 | ||
| 124 | static inline void x86_init_rdrand(struct cpuinfo_x86 *c) { } | |
| 125 | ||
| 126 | #endif /* !CONFIG_ARCH_RANDOM */ | |
| 127 | ||
| 628c6246 | 128 | #endif /* ASM_X86_ARCHRANDOM_H */ |