cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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archrandom.h (2347B)

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