LCOV - code coverage report
Current view: top level - arch/x86/include/asm - archrandom.h (source / functions) Hit Total Coverage
Test: landlock.info Lines: 12 18 66.7 %
Date: 2021-04-22 12:43:58 Functions: 3 3 100.0 %

          Line data    Source code
       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             : 
      20             : static inline bool __must_check rdrand_long(unsigned long *v)
      21             : {
      22             :         bool ok;
      23             :         unsigned int retry = RDRAND_RETRY_LOOPS;
      24        3028 :         do {
      25        5992 :                 asm volatile("rdrand %[out]"
      26             :                              CC_SET(c)
      27             :                              : CC_OUT(c) (ok), [out] "=r" (*v));
      28        3028 :                 if (ok)
      29             :                         return true;
      30           0 :         } while (--retry);
      31             :         return false;
      32             : }
      33             : 
      34             : static inline bool __must_check rdrand_int(unsigned int *v)
      35             : {
      36             :         bool ok;
      37             :         unsigned int retry = RDRAND_RETRY_LOOPS;
      38         132 :         do {
      39         264 :                 asm volatile("rdrand %[out]"
      40             :                              CC_SET(c)
      41             :                              : CC_OUT(c) (ok), [out] "=r" (*v));
      42         132 :                 if (ok)
      43             :                         return true;
      44           0 :         } while (--retry);
      45             :         return false;
      46             : }
      47             : 
      48           0 : static inline bool __must_check rdseed_long(unsigned long *v)
      49             : {
      50           0 :         bool ok;
      51           0 :         asm volatile("rdseed %[out]"
      52             :                      CC_SET(c)
      53             :                      : CC_OUT(c) (ok), [out] "=r" (*v));
      54           0 :         return ok;
      55             : }
      56             : 
      57             : static 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             : 
      73        2964 : static inline bool __must_check arch_get_random_long(unsigned long *v)
      74             : {
      75        8892 :         return static_cpu_has(X86_FEATURE_RDRAND) ? rdrand_long(v) : false;
      76             : }
      77             : 
      78         132 : static inline bool __must_check arch_get_random_int(unsigned int *v)
      79             : {
      80         396 :         return static_cpu_has(X86_FEATURE_RDRAND) ? rdrand_int(v) : false;
      81             : }
      82             : 
      83          96 : static inline bool __must_check arch_get_random_seed_long(unsigned long *v)
      84             : {
      85          96 :         return static_cpu_has(X86_FEATURE_RDSEED) ? rdseed_long(v) : false;
      86             : }
      87             : 
      88             : static 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             : 
      93             : extern void x86_init_rdrand(struct cpuinfo_x86 *c);
      94             : 
      95             : #else  /* !CONFIG_ARCH_RANDOM */
      96             : 
      97             : static inline void x86_init_rdrand(struct cpuinfo_x86 *c) { }
      98             : 
      99             : #endif  /* !CONFIG_ARCH_RANDOM */
     100             : 
     101             : #endif /* ASM_X86_ARCHRANDOM_H */

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