arch/s390/include/asm/archrandom.h

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