arch/s390/include/asm/preempt.h

   1 #ifndef __ASM_PREEMPT_H
   2 #define __ASM_PREEMPT_H
   3
   4 #include <asm/current.h>
   5 #include <linux/thread_info.h>
   6 #include <asm/atomic_ops.h>
   7
   8 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
   9
  10 #define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED)
  11
  12 static inline int preempt_count(void)
  13 {
  14         return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED;
  15 }
  16
  17 static inline void preempt_count_set(int pc)
  18 {
  19         int old, new;
  20
  21         do {
  22                 old = READ_ONCE(S390_lowcore.preempt_count);
  23                 new = (old & PREEMPT_NEED_RESCHED) |
  24                         (pc & ~PREEMPT_NEED_RESCHED);
  25         } while (__atomic_cmpxchg(&S390_lowcore.preempt_count,
  26                                   old, new) != old);
  27 }
  28
  29 #define init_task_preempt_count(p)      do { } while (0)
  30
  31 #define init_idle_preempt_count(p, cpu) do { \
  32         S390_lowcore.preempt_count = PREEMPT_ENABLED; \
  33 } while (0)
  34
  35 static inline void set_preempt_need_resched(void)
  36 {
  37         __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
  38 }
  39
  40 static inline void clear_preempt_need_resched(void)
  41 {
  42         __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
  43 }
  44
  45 static inline bool test_preempt_need_resched(void)
  46 {
  47         return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED);
  48 }
  49
  50 static inline void __preempt_count_add(int val)
  51 {
  52         if (__builtin_constant_p(val) && (val >= -128) && (val <= 127))
  53                 __atomic_add_const(val, &S390_lowcore.preempt_count);
  54         else
  55                 __atomic_add(val, &S390_lowcore.preempt_count);
  56 }
  57
  58 static inline void __preempt_count_sub(int val)
  59 {
  60         __preempt_count_add(-val);
  61 }
  62
  63 static inline bool __preempt_count_dec_and_test(void)
  64 {
  65         return __atomic_add(-1, &S390_lowcore.preempt_count) == 1;
  66 }
  67
  68 static inline bool should_resched(int preempt_offset)
  69 {
  70         return unlikely(READ_ONCE(S390_lowcore.preempt_count) ==
  71                         preempt_offset);
  72 }
  73
  74 #else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
  75
  76 #define PREEMPT_ENABLED (0)
  77
  78 static inline int preempt_count(void)
  79 {
  80         return READ_ONCE(S390_lowcore.preempt_count);
  81 }
  82
  83 static inline void preempt_count_set(int pc)
  84 {
  85         S390_lowcore.preempt_count = pc;
  86 }
  87
  88 #define init_task_preempt_count(p)      do { } while (0)
  89
  90 #define init_idle_preempt_count(p, cpu) do { \
  91         S390_lowcore.preempt_count = PREEMPT_ENABLED; \
  92 } while (0)
  93
  94 static inline void set_preempt_need_resched(void)
  95 {
  96 }
  97
  98 static inline void clear_preempt_need_resched(void)
  99 {
 100 }
 101
 102 static inline bool test_preempt_need_resched(void)
 103 {
 104         return false;
 105 }
 106
 107 static inline void __preempt_count_add(int val)
 108 {
 109         S390_lowcore.preempt_count += val;
 110 }
 111
 112 static inline void __preempt_count_sub(int val)
 113 {
 114         S390_lowcore.preempt_count -= val;
 115 }
 116
 117 static inline bool __preempt_count_dec_and_test(void)
 118 {
 119         return !--S390_lowcore.preempt_count && tif_need_resched();
 120 }
 121
 122 static inline bool should_resched(int preempt_offset)
 123 {
 124         return unlikely(preempt_count() == preempt_offset &&
 125                         tif_need_resched());
 126 }
 127
 128 #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
 129
 130 #ifdef CONFIG_PREEMPT
 131 extern asmlinkage void preempt_schedule(void);
 132 #define __preempt_schedule() preempt_schedule()
 133 extern asmlinkage void preempt_schedule_notrace(void);
 134 #define __preempt_schedule_notrace() preempt_schedule_notrace()
 135 #endif /* CONFIG_PREEMPT */
 136
 137 #endif /* __ASM_PREEMPT_H */