diff options
Diffstat (limited to 'arch/x86/include/asm/archrandom.h')
| -rw-r--r-- | arch/x86/include/asm/archrandom.h | 89 |
1 files changed, 37 insertions, 52 deletions
diff --git a/arch/x86/include/asm/archrandom.h b/arch/x86/include/asm/archrandom.h index 0d9ec770f2f8..4c305305871b 100644 --- a/arch/x86/include/asm/archrandom.h +++ b/arch/x86/include/asm/archrandom.h @@ -1,23 +1,10 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ /* * This file is part of the Linux kernel. * - * Copyright (c) 2011, Intel Corporation + * Copyright (c) 2011-2014, 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 @@ -25,51 +12,49 @@ #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; \ +/* Unconditional execution of RDRAND and RDSEED */ + +static inline bool __must_check rdrand_long(unsigned long *v) +{ + bool ok; + unsigned int retry = RDRAND_RETRY_LOOPS; + do { + asm volatile("rdrand %[out]" + : "=@ccc" (ok), [out] "=r" (*v)); + if (ok) + return true; + } while (--retry); + return false; } -#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 +static inline bool __must_check rdseed_long(unsigned long *v) +{ + bool ok; + asm volatile("rdseed %[out]" + : "=@ccc" (ok), [out] "=r" (*v)); + return ok; +} -GET_RANDOM(arch_get_random_long, unsigned long, RDRAND_LONG, ASM_NOP3); -GET_RANDOM(arch_get_random_int, unsigned int, RDRAND_INT, ASM_NOP3); +/* + * These are the generic interfaces; they must not be declared if the + * stubs in <linux/random.h> are to be invoked. + */ -#endif /* CONFIG_X86_64 */ +static inline size_t __must_check arch_get_random_longs(unsigned long *v, size_t max_longs) +{ + return max_longs && static_cpu_has(X86_FEATURE_RDRAND) && rdrand_long(v) ? 1 : 0; +} -#endif /* CONFIG_ARCH_RANDOM */ +static inline size_t __must_check arch_get_random_seed_longs(unsigned long *v, size_t max_longs) +{ + return max_longs && static_cpu_has(X86_FEATURE_RDSEED) && rdseed_long(v) ? 1 : 0; +} -extern void x86_init_rdrand(struct cpuinfo_x86 *c); +#ifndef CONFIG_UML +void x86_init_rdrand(struct cpuinfo_x86 *c); +#endif #endif /* ASM_X86_ARCHRANDOM_H */ |