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> | |
28 | #include <asm/alternative.h> | |
29 | #include <asm/nops.h> | |
30 | ||
31 | #define RDRAND_RETRY_LOOPS 10 | |
32 | ||
33 | #define RDRAND_INT ".byte 0x0f,0xc7,0xf0" | |
d20f78d2 | 34 | #define RDSEED_INT ".byte 0x0f,0xc7,0xf8" |
628c6246 PA |
35 | #ifdef CONFIG_X86_64 |
36 | # define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0" | |
d20f78d2 | 37 | # define RDSEED_LONG ".byte 0x48,0x0f,0xc7,0xf8" |
628c6246 PA |
38 | #else |
39 | # define RDRAND_LONG RDRAND_INT | |
d20f78d2 | 40 | # define RDSEED_LONG RDSEED_INT |
628c6246 PA |
41 | #endif |
42 | ||
43 | #ifdef CONFIG_ARCH_RANDOM | |
44 | ||
5bfce5ef KC |
45 | /* Instead of arch_get_random_long() when alternatives haven't run. */ |
46 | static inline int rdrand_long(unsigned long *v) | |
47 | { | |
48 | int ok; | |
49 | asm volatile("1: " RDRAND_LONG "\n\t" | |
50 | "jc 2f\n\t" | |
51 | "decl %0\n\t" | |
52 | "jnz 1b\n\t" | |
53 | "2:" | |
54 | : "=r" (ok), "=a" (*v) | |
55 | : "0" (RDRAND_RETRY_LOOPS)); | |
56 | return ok; | |
57 | } | |
58 | ||
d20f78d2 PA |
59 | /* A single attempt at RDSEED */ |
60 | static inline bool rdseed_long(unsigned long *v) | |
61 | { | |
62 | unsigned char ok; | |
63 | asm volatile(RDSEED_LONG "\n\t" | |
64 | "setc %0" | |
65 | : "=qm" (ok), "=a" (*v)); | |
66 | return ok; | |
67 | } | |
68 | ||
628c6246 PA |
69 | #define GET_RANDOM(name, type, rdrand, nop) \ |
70 | static inline int name(type *v) \ | |
71 | { \ | |
72 | int ok; \ | |
73 | alternative_io("movl $0, %0\n\t" \ | |
74 | nop, \ | |
75 | "\n1: " rdrand "\n\t" \ | |
76 | "jc 2f\n\t" \ | |
77 | "decl %0\n\t" \ | |
78 | "jnz 1b\n\t" \ | |
79 | "2:", \ | |
80 | X86_FEATURE_RDRAND, \ | |
81 | ASM_OUTPUT2("=r" (ok), "=a" (*v)), \ | |
82 | "0" (RDRAND_RETRY_LOOPS)); \ | |
83 | return ok; \ | |
84 | } | |
85 | ||
d20f78d2 PA |
86 | #define GET_SEED(name, type, rdseed, nop) \ |
87 | static inline int name(type *v) \ | |
88 | { \ | |
89 | unsigned char ok; \ | |
90 | alternative_io("movb $0, %0\n\t" \ | |
91 | nop, \ | |
92 | rdseed "\n\t" \ | |
93 | "setc %0", \ | |
94 | X86_FEATURE_RDSEED, \ | |
95 | ASM_OUTPUT2("=q" (ok), "=a" (*v))); \ | |
96 | return ok; \ | |
97 | } | |
98 | ||
628c6246 PA |
99 | #ifdef CONFIG_X86_64 |
100 | ||
101 | GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5); | |
102 | GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4); | |
103 | ||
d20f78d2 PA |
104 | GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP5); |
105 | GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4); | |
106 | ||
628c6246 PA |
107 | #else |
108 | ||
109 | GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3); | |
110 | GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3); | |
111 | ||
d20f78d2 PA |
112 | GET_SEED(arch_get_random_seed_long, unsigned long, RDSEED_LONG, ASM_NOP4); |
113 | GET_SEED(arch_get_random_seed_int, unsigned int, RDSEED_INT, ASM_NOP4); | |
114 | ||
628c6246 PA |
115 | #endif /* CONFIG_X86_64 */ |
116 | ||
7b878d4b PA |
117 | #define arch_has_random() static_cpu_has(X86_FEATURE_RDRAND) |
118 | #define arch_has_random_seed() static_cpu_has(X86_FEATURE_RDSEED) | |
119 | ||
5bfce5ef KC |
120 | #else |
121 | ||
122 | static inline int rdrand_long(unsigned long *v) | |
123 | { | |
124 | return 0; | |
125 | } | |
126 | ||
d20f78d2 PA |
127 | static inline bool rdseed_long(unsigned long *v) |
128 | { | |
129 | return 0; | |
130 | } | |
131 | ||
628c6246 PA |
132 | #endif /* CONFIG_ARCH_RANDOM */ |
133 | ||
49d859d7 PA |
134 | extern void x86_init_rdrand(struct cpuinfo_x86 *c); |
135 | ||
628c6246 | 136 | #endif /* ASM_X86_ARCHRANDOM_H */ |