| H. Peter Anvin | 628c624 | 2011-07-31 13:59:29 -0700 | [diff] [blame] | 1 | /* |
| 2 | * This file is part of the Linux kernel. |
| 3 | * |
| 4 | * Copyright (c) 2011, Intel Corporation |
| 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" |
| 34 | #ifdef CONFIG_X86_64 |
| 35 | # define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0" |
| 36 | #else |
| 37 | # define RDRAND_LONG RDRAND_INT |
| 38 | #endif |
| 39 | |
| 40 | #ifdef CONFIG_ARCH_RANDOM |
| 41 | |
| 42 | #define GET_RANDOM(name, type, rdrand, nop) \ |
| 43 | static inline int name(type *v) \ |
| 44 | { \ |
| 45 | int ok; \ |
| 46 | alternative_io("movl $0, %0\n\t" \ |
| 47 | nop, \ |
| 48 | "\n1: " rdrand "\n\t" \ |
| 49 | "jc 2f\n\t" \ |
| 50 | "decl %0\n\t" \ |
| 51 | "jnz 1b\n\t" \ |
| 52 | "2:", \ |
| 53 | X86_FEATURE_RDRAND, \ |
| 54 | ASM_OUTPUT2("=r" (ok), "=a" (*v)), \ |
| 55 | "0" (RDRAND_RETRY_LOOPS)); \ |
| 56 | return ok; \ |
| 57 | } |
| 58 | |
| 59 | #ifdef CONFIG_X86_64 |
| 60 | |
| 61 | GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5); |
| 62 | GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4); |
| 63 | |
| 64 | #else |
| 65 | |
| 66 | GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3); |
| 67 | GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3); |
| 68 | |
| 69 | #endif /* CONFIG_X86_64 */ |
| 70 | |
| 71 | #endif /* CONFIG_ARCH_RANDOM */ |
| 72 | |
| H. Peter Anvin | 49d859d | 2011-07-31 14:02:19 -0700 | [diff] [blame] | 73 | extern void x86_init_rdrand(struct cpuinfo_x86 *c); |
| 74 | |
| H. Peter Anvin | 628c624 | 2011-07-31 13:59:29 -0700 | [diff] [blame] | 75 | #endif /* ASM_X86_ARCHRANDOM_H */ |