arch/s390/include/asm/archrandom.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * Kernel interface for the s390 arch_random_* functions
   4  *
   5  * Copyright IBM Corp. 2017
   6  *
   7  * Author: Harald Freudenberger <freude@de.ibm.com>
   8  *
   9  */
  10
  11 #ifndef _ASM_S390_ARCHRANDOM_H
  12 #define _ASM_S390_ARCHRANDOM_H
  13
  14 #ifdef CONFIG_ARCH_RANDOM
  15
  16 #include <linux/static_key.h>
  17 #include <linux/atomic.h>
  18 #include <asm/cpacf.h>
  19
  20 DECLARE_STATIC_KEY_FALSE(s390_arch_random_available);
  21 extern atomic64_t s390_arch_random_counter;
  22
  23 static void s390_arch_random_generate(u8 *buf, unsigned int nbytes)
  24 {
  25         cpacf_trng(NULL, 0, buf, nbytes);
  26         atomic64_add(nbytes, &s390_arch_random_counter);
  27 }
  28
  29 static inline bool arch_has_random(void)
  30 {
  31         return false;
  32 }
  33
  34 static inline bool arch_has_random_seed(void)
  35 {
  36         if (static_branch_likely(&s390_arch_random_available))
  37                 return true;
  38         return false;
  39 }
  40
  41 static inline bool arch_get_random_long(unsigned long *v)
  42 {
  43         return false;
  44 }
  45
  46 static inline bool arch_get_random_int(unsigned int *v)
  47 {
  48         return false;
  49 }
  50
  51 static inline bool arch_get_random_seed_long(unsigned long *v)
  52 {
  53         if (static_branch_likely(&s390_arch_random_available)) {
  54                 s390_arch_random_generate((u8 *)v, sizeof(*v));
  55                 return true;
  56         }
  57         return false;
  58 }
  59
  60 static inline bool arch_get_random_seed_int(unsigned int *v)
  61 {
  62         if (static_branch_likely(&s390_arch_random_available)) {
  63                 s390_arch_random_generate((u8 *)v, sizeof(*v));
  64                 return true;
  65         }
  66         return false;
  67 }
  68
  69 #endif /* CONFIG_ARCH_RANDOM */
  70 #endif /* _ASM_S390_ARCHRANDOM_H */