/* SPDX-License-Identifier: GPL-2.0-only */ /* * This file is part of the Linux kernel. * * Copyright (c) 2011-2014, Intel Corporation * Authors: Fenghua Yu <fenghua.yu@intel.com>, * H. Peter Anvin <hpa@linux.intel.com> */ #ifndef ASM_X86_ARCHRANDOM_H #define ASM_X86_ARCHRANDOM_H #include <asm/processor.h> #include <asm/cpufeature.h> #define RDRAND_RETRY_LOOPS 10 /* 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]" CC_SET(c) : CC_OUT(c) (ok), [out] "=r" (*v)); if (ok) return true; } while (--retry); return false; } static inline bool __must_check rdrand_int(unsigned int *v) { bool ok; unsigned int retry = RDRAND_RETRY_LOOPS; do { asm volatile("rdrand %[out]" CC_SET(c) : CC_OUT(c) (ok), [out] "=r" (*v)); if (ok) return true; } while (--retry); return false; } static inline bool __must_check rdseed_long(unsigned long *v) { bool ok; asm volatile("rdseed %[out]" CC_SET(c) : CC_OUT(c) (ok), [out] "=r" (*v)); return ok; } static inline bool __must_check rdseed_int(unsigned int *v) { bool ok; asm volatile("rdseed %[out]" CC_SET(c) : CC_OUT(c) (ok), [out] "=r" (*v)); return ok; } /* * These are the generic interfaces; they must not be declared if the * stubs in <linux/random.h> are to be invoked, * i.e. CONFIG_ARCH_RANDOM is not defined. */ #ifdef CONFIG_ARCH_RANDOM static inline bool __must_check arch_get_random_long(unsigned long *v) { return static_cpu_has(X86_FEATURE_RDRAND) ? rdrand_long(v) : false; } static inline bool __must_check arch_get_random_int(unsigned int *v) { return static_cpu_has(X86_FEATURE_RDRAND) ? rdrand_int(v) : false; } static inline bool __must_check arch_get_random_seed_long(unsigned long *v) { return static_cpu_has(X86_FEATURE_RDSEED) ? rdseed_long(v) : false; } static inline bool __must_check arch_get_random_seed_int(unsigned int *v) { return static_cpu_has(X86_FEATURE_RDSEED) ? rdseed_int(v) : false; } extern void x86_init_rdrand(struct cpuinfo_x86 *c); #else /* !CONFIG_ARCH_RANDOM */ static inline void x86_init_rdrand(struct cpuinfo_x86 *c) { } #endif /* !CONFIG_ARCH_RANDOM */ #endif /* ASM_X86_ARCHRANDOM_H */