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Diffstat (limited to 'arch/x86/include/asm/archrandom.h')
| -rw-r--r-- | arch/x86/include/asm/archrandom.h | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h new file mode 100644 index 00000000000..0d9ec770f2f --- /dev/null +++ b/arch/x86/include/asm/archrandom.h @@ -0,0 +1,75 @@ +/* + * This file is part of the Linux kernel. + * + * Copyright (c) 2011, Intel Corporation + * Authors: Fenghua Yu <fenghua.yu@intel.com>, + * H. Peter Anvin <hpa@linux.intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * You should have received a copy of the GNU General Public License along with + * this program; if not, write to the Free Software Foundation, Inc., + * 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. + * + */ + +#ifndef ASM_X86_ARCHRANDOM_H +#define ASM_X86_ARCHRANDOM_H + +#include <asm/processor.h> +#include <asm/cpufeature.h> +#include <asm/alternative.h> +#include <asm/nops.h> + +#define RDRAND_RETRY_LOOPS 10 + +#define RDRAND_INT ".byte 0x0f,0xc7,0xf0" +#ifdef CONFIG_X86_64 +# define RDRAND_LONG ".byte 0x48,0x0f,0xc7,0xf0" +#else +# define RDRAND_LONG RDRAND_INT +#endif + +#ifdef CONFIG_ARCH_RANDOM + +#define GET_RANDOM(name, type, rdrand, nop) \ +static inline int name(type *v) \ +{ \ + int ok; \ + alternative_io("movl $0, %0\n\t" \ + nop, \ + "\n1: " rdrand "\n\t" \ + "jc 2f\n\t" \ + "decl %0\n\t" \ + "jnz 1b\n\t" \ + "2:", \ + X86_FEATURE_RDRAND, \ + ASM_OUTPUT2("=r" (ok), "=a" (*v)), \ + "0" (RDRAND_RETRY_LOOPS)); \ + return ok; \ +} + +#ifdef CONFIG_X86_64 + +GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP5); +GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP4); + +#else + +GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3); +GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3); + +#endif /* CONFIG_X86_64 */ + +#endif /* CONFIG_ARCH_RANDOM */ + +extern void x86_init_rdrand(struct cpuinfo_x86 *c); + +#endif /* ASM_X86_ARCHRANDOM_H */ |