tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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) \
43static 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
61GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5);
62GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4);
63
64#else
65
66GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3);
67GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3);
68
69#endif /* CONFIG_X86_64 */
70
71#endif /* CONFIG_ARCH_RANDOM */
72
73extern void x86_init_rdrand(struct cpuinfo_x86 *c);
74
75#endif /* ASM_X86_ARCHRANDOM_H */