arch/s390/include/asm/preempt.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef __ASM_PREEMPT_H
   3 #define __ASM_PREEMPT_H
   4
   5 #include <asm/current.h>
   6 #include <linux/thread_info.h>
   7 #include <asm/atomic_ops.h>
   8
   9 #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES
  10
  11 #define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED)
  12
  13 static inline int preempt_count(void)
  14 {
  15         return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED;
  16 }
  17
  18 static inline void preempt_count_set(int pc)
  19 {
  20         int old, new;
  21
  22         do {
  23                 old = READ_ONCE(S390_lowcore.preempt_count);
  24                 new = (old & PREEMPT_NEED_RESCHED) |
  25                         (pc & ~PREEMPT_NEED_RESCHED);
  26         } while (__atomic_cmpxchg(&S390_lowcore.preempt_count,
  27                                   old, new) != old);
  28 }
  29
  30 #define init_task_preempt_count(p)      do { } while (0)
  31
  32 #define init_idle_preempt_count(p, cpu) do { \
  33         S390_lowcore.preempt_count = PREEMPT_ENABLED; \
  34 } while (0)
  35
  36 static inline void set_preempt_need_resched(void)
  37 {
  38         __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
  39 }
  40
  41 static inline void clear_preempt_need_resched(void)
  42 {
  43         __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
  44 }
  45
  46 static inline bool test_preempt_need_resched(void)
  47 {
  48         return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED);
  49 }
  50
  51 static inline void __preempt_count_add(int val)
  52 {
  53         if (__builtin_constant_p(val) && (val >= -128) && (val <= 127))
  54                 __atomic_add_const(val, &S390_lowcore.preempt_count);
  55         else
  56                 __atomic_add(val, &S390_lowcore.preempt_count);
  57 }
  58
  59 static inline void __preempt_count_sub(int val)
  60 {
  61         __preempt_count_add(-val);
  62 }
  63
  64 static inline bool __preempt_count_dec_and_test(void)
  65 {
  66         return __atomic_add(-1, &S390_lowcore.preempt_count) == 1;
  67 }
  68
  69 static inline bool should_resched(int preempt_offset)
  70 {
  71         return unlikely(READ_ONCE(S390_lowcore.preempt_count) ==
  72                         preempt_offset);
  73 }
  74
  75 #else /* CONFIG_HAVE_MARCH_Z196_FEATURES */
  76
  77 #define PREEMPT_ENABLED (0)
  78
  79 static inline int preempt_count(void)
  80 {
  81         return READ_ONCE(S390_lowcore.preempt_count);
  82 }
  83
  84 static inline void preempt_count_set(int pc)
  85 {
  86         S390_lowcore.preempt_count = pc;
  87 }
  88
  89 #define init_task_preempt_count(p)      do { } while (0)
  90
  91 #define init_idle_preempt_count(p, cpu) do { \
  92         S390_lowcore.preempt_count = PREEMPT_ENABLED; \
  93 } while (0)
  94
  95 static inline void set_preempt_need_resched(void)
  96 {
  97 }
  98
  99 static inline void clear_preempt_need_resched(void)
 100 {
 101 }
 102
 103 static inline bool test_preempt_need_resched(void)
 104 {
 105         return false;
 106 }
 107
 108 static inline void __preempt_count_add(int val)
 109 {
 110         S390_lowcore.preempt_count += val;
 111 }
 112
 113 static inline void __preempt_count_sub(int val)
 114 {
 115         S390_lowcore.preempt_count -= val;
 116 }
 117
 118 static inline bool __preempt_count_dec_and_test(void)
 119 {
 120         return !--S390_lowcore.preempt_count && tif_need_resched();
 121 }
 122
 123 static inline bool should_resched(int preempt_offset)
 124 {
 125         return unlikely(preempt_count() == preempt_offset &&
 126                         tif_need_resched());
 127 }
 128
 129 #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */
 130
 131 #ifdef CONFIG_PREEMPT
 132 extern asmlinkage void preempt_schedule(void);
 133 #define __preempt_schedule() preempt_schedule()
 134 extern asmlinkage void preempt_schedule_notrace(void);
 135 #define __preempt_schedule_notrace() preempt_schedule_notrace()
 136 #endif /* CONFIG_PREEMPT */
 137
 138 #endif /* __ASM_PREEMPT_H */