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 */ 139