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 /* We use the MSB mostly because its available */ 12 #define PREEMPT_NEED_RESCHED 0x80000000 13 #define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED) 14 15 static inline int preempt_count(void) 16 { 17 return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED; 18 } 19 20 static inline void preempt_count_set(int pc) 21 { 22 int old, new; 23 24 do { 25 old = READ_ONCE(S390_lowcore.preempt_count); 26 new = (old & PREEMPT_NEED_RESCHED) | 27 (pc & ~PREEMPT_NEED_RESCHED); 28 } while (__atomic_cmpxchg(&S390_lowcore.preempt_count, 29 old, new) != old); 30 } 31 32 #define init_task_preempt_count(p) do { } while (0) 33 34 #define init_idle_preempt_count(p, cpu) do { \ 35 S390_lowcore.preempt_count = PREEMPT_ENABLED; \ 36 } while (0) 37 38 static inline void set_preempt_need_resched(void) 39 { 40 __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count); 41 } 42 43 static inline void clear_preempt_need_resched(void) 44 { 45 __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count); 46 } 47 48 static inline bool test_preempt_need_resched(void) 49 { 50 return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED); 51 } 52 53 static inline void __preempt_count_add(int val) 54 { 55 if (__builtin_constant_p(val) && (val >= -128) && (val <= 127)) 56 __atomic_add_const(val, &S390_lowcore.preempt_count); 57 else 58 __atomic_add(val, &S390_lowcore.preempt_count); 59 } 60 61 static inline void __preempt_count_sub(int val) 62 { 63 __preempt_count_add(-val); 64 } 65 66 static inline bool __preempt_count_dec_and_test(void) 67 { 68 return __atomic_add(-1, &S390_lowcore.preempt_count) == 1; 69 } 70 71 static inline bool should_resched(int preempt_offset) 72 { 73 return unlikely(READ_ONCE(S390_lowcore.preempt_count) == 74 preempt_offset); 75 } 76 77 #else /* CONFIG_HAVE_MARCH_Z196_FEATURES */ 78 79 #define PREEMPT_ENABLED (0) 80 81 static inline int preempt_count(void) 82 { 83 return READ_ONCE(S390_lowcore.preempt_count); 84 } 85 86 static inline void preempt_count_set(int pc) 87 { 88 S390_lowcore.preempt_count = pc; 89 } 90 91 #define init_task_preempt_count(p) do { } while (0) 92 93 #define init_idle_preempt_count(p, cpu) do { \ 94 S390_lowcore.preempt_count = PREEMPT_ENABLED; \ 95 } while (0) 96 97 static inline void set_preempt_need_resched(void) 98 { 99 } 100 101 static inline void clear_preempt_need_resched(void) 102 { 103 } 104 105 static inline bool test_preempt_need_resched(void) 106 { 107 return false; 108 } 109 110 static inline void __preempt_count_add(int val) 111 { 112 S390_lowcore.preempt_count += val; 113 } 114 115 static inline void __preempt_count_sub(int val) 116 { 117 S390_lowcore.preempt_count -= val; 118 } 119 120 static inline bool __preempt_count_dec_and_test(void) 121 { 122 return !--S390_lowcore.preempt_count && tif_need_resched(); 123 } 124 125 static inline bool should_resched(int preempt_offset) 126 { 127 return unlikely(preempt_count() == preempt_offset && 128 tif_need_resched()); 129 } 130 131 #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */ 132 133 #ifdef CONFIG_PREEMPT 134 extern asmlinkage void preempt_schedule(void); 135 #define __preempt_schedule() preempt_schedule() 136 extern asmlinkage void preempt_schedule_notrace(void); 137 #define __preempt_schedule_notrace() preempt_schedule_notrace() 138 #endif /* CONFIG_PREEMPT */ 139 140 #endif /* __ASM_PREEMPT_H */ 141