1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0-only */ 2*4882a593Smuzhiyun /* 3*4882a593Smuzhiyun * This file is part of the Linux kernel. 4*4882a593Smuzhiyun * 5*4882a593Smuzhiyun * Copyright (c) 2011-2014, Intel Corporation 6*4882a593Smuzhiyun * Authors: Fenghua Yu <fenghua.yu@intel.com>, 7*4882a593Smuzhiyun * H. Peter Anvin <hpa@linux.intel.com> 8*4882a593Smuzhiyun */ 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun #ifndef ASM_X86_ARCHRANDOM_H 11*4882a593Smuzhiyun #define ASM_X86_ARCHRANDOM_H 12*4882a593Smuzhiyun 13*4882a593Smuzhiyun #include <asm/processor.h> 14*4882a593Smuzhiyun #include <asm/cpufeature.h> 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun #define RDRAND_RETRY_LOOPS 10 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun /* Unconditional execution of RDRAND and RDSEED */ 19*4882a593Smuzhiyun rdrand_long(unsigned long * v)20*4882a593Smuzhiyunstatic inline bool __must_check rdrand_long(unsigned long *v) 21*4882a593Smuzhiyun { 22*4882a593Smuzhiyun bool ok; 23*4882a593Smuzhiyun unsigned int retry = RDRAND_RETRY_LOOPS; 24*4882a593Smuzhiyun do { 25*4882a593Smuzhiyun asm volatile("rdrand %[out]" 26*4882a593Smuzhiyun CC_SET(c) 27*4882a593Smuzhiyun : CC_OUT(c) (ok), [out] "=r" (*v)); 28*4882a593Smuzhiyun if (ok) 29*4882a593Smuzhiyun return true; 30*4882a593Smuzhiyun } while (--retry); 31*4882a593Smuzhiyun return false; 32*4882a593Smuzhiyun } 33*4882a593Smuzhiyun rdrand_int(unsigned int * v)34*4882a593Smuzhiyunstatic inline bool __must_check rdrand_int(unsigned int *v) 35*4882a593Smuzhiyun { 36*4882a593Smuzhiyun bool ok; 37*4882a593Smuzhiyun unsigned int retry = RDRAND_RETRY_LOOPS; 38*4882a593Smuzhiyun do { 39*4882a593Smuzhiyun asm volatile("rdrand %[out]" 40*4882a593Smuzhiyun CC_SET(c) 41*4882a593Smuzhiyun : CC_OUT(c) (ok), [out] "=r" (*v)); 42*4882a593Smuzhiyun if (ok) 43*4882a593Smuzhiyun return true; 44*4882a593Smuzhiyun } while (--retry); 45*4882a593Smuzhiyun return false; 46*4882a593Smuzhiyun } 47*4882a593Smuzhiyun rdseed_long(unsigned long * v)48*4882a593Smuzhiyunstatic inline bool __must_check rdseed_long(unsigned long *v) 49*4882a593Smuzhiyun { 50*4882a593Smuzhiyun bool ok; 51*4882a593Smuzhiyun asm volatile("rdseed %[out]" 52*4882a593Smuzhiyun CC_SET(c) 53*4882a593Smuzhiyun : CC_OUT(c) (ok), [out] "=r" (*v)); 54*4882a593Smuzhiyun return ok; 55*4882a593Smuzhiyun } 56*4882a593Smuzhiyun rdseed_int(unsigned int * v)57*4882a593Smuzhiyunstatic inline bool __must_check rdseed_int(unsigned int *v) 58*4882a593Smuzhiyun { 59*4882a593Smuzhiyun bool ok; 60*4882a593Smuzhiyun asm volatile("rdseed %[out]" 61*4882a593Smuzhiyun CC_SET(c) 62*4882a593Smuzhiyun : CC_OUT(c) (ok), [out] "=r" (*v)); 63*4882a593Smuzhiyun return ok; 64*4882a593Smuzhiyun } 65*4882a593Smuzhiyun 66*4882a593Smuzhiyun /* 67*4882a593Smuzhiyun * These are the generic interfaces; they must not be declared if the 68*4882a593Smuzhiyun * stubs in <linux/random.h> are to be invoked, 69*4882a593Smuzhiyun * i.e. CONFIG_ARCH_RANDOM is not defined. 70*4882a593Smuzhiyun */ 71*4882a593Smuzhiyun #ifdef CONFIG_ARCH_RANDOM 72*4882a593Smuzhiyun arch_get_random_long(unsigned long * v)73*4882a593Smuzhiyunstatic inline bool __must_check arch_get_random_long(unsigned long *v) 74*4882a593Smuzhiyun { 75*4882a593Smuzhiyun return static_cpu_has(X86_FEATURE_RDRAND) ? rdrand_long(v) : false; 76*4882a593Smuzhiyun } 77*4882a593Smuzhiyun arch_get_random_int(unsigned int * v)78*4882a593Smuzhiyunstatic inline bool __must_check arch_get_random_int(unsigned int *v) 79*4882a593Smuzhiyun { 80*4882a593Smuzhiyun return static_cpu_has(X86_FEATURE_RDRAND) ? rdrand_int(v) : false; 81*4882a593Smuzhiyun } 82*4882a593Smuzhiyun arch_get_random_seed_long(unsigned long * v)83*4882a593Smuzhiyunstatic inline bool __must_check arch_get_random_seed_long(unsigned long *v) 84*4882a593Smuzhiyun { 85*4882a593Smuzhiyun return static_cpu_has(X86_FEATURE_RDSEED) ? rdseed_long(v) : false; 86*4882a593Smuzhiyun } 87*4882a593Smuzhiyun arch_get_random_seed_int(unsigned int * v)88*4882a593Smuzhiyunstatic inline bool __must_check arch_get_random_seed_int(unsigned int *v) 89*4882a593Smuzhiyun { 90*4882a593Smuzhiyun return static_cpu_has(X86_FEATURE_RDSEED) ? rdseed_int(v) : false; 91*4882a593Smuzhiyun } 92*4882a593Smuzhiyun 93*4882a593Smuzhiyun extern void x86_init_rdrand(struct cpuinfo_x86 *c); 94*4882a593Smuzhiyun 95*4882a593Smuzhiyun #else /* !CONFIG_ARCH_RANDOM */ 96*4882a593Smuzhiyun x86_init_rdrand(struct cpuinfo_x86 * c)97*4882a593Smuzhiyunstatic inline void x86_init_rdrand(struct cpuinfo_x86 *c) { } 98*4882a593Smuzhiyun 99*4882a593Smuzhiyun #endif /* !CONFIG_ARCH_RANDOM */ 100*4882a593Smuzhiyun 101*4882a593Smuzhiyun #endif /* ASM_X86_ARCHRANDOM_H */ 102