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 static inline void set_preempt_need_resched(void) 33 { 34 __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count); 35 } 36 37 static inline void clear_preempt_need_resched(void) 38 { 39 __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count); 40 } 41 42 static inline bool test_preempt_need_resched(void) 43 { 44 return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED); 45 } 46 47 static inline void __preempt_count_add(int val) 48 { 49 if (__builtin_constant_p(val) && (val >= -128) && (val <= 127)) 50 __atomic_add_const(val, &S390_lowcore.preempt_count); 51 else 52 __atomic_add(val, &S390_lowcore.preempt_count); 53 } 54 55 static inline void __preempt_count_sub(int val) 56 { 57 __preempt_count_add(-val); 58 } 59 60 static inline bool __preempt_count_dec_and_test(void) 61 { 62 return __atomic_add(-1, &S390_lowcore.preempt_count) == 1; 63 } 64 65 static inline bool should_resched(int preempt_offset) 66 { 67 return unlikely(READ_ONCE(S390_lowcore.preempt_count) == 68 preempt_offset); 69 } 70 71 #else /* CONFIG_HAVE_MARCH_Z196_FEATURES */ 72 73 #define PREEMPT_ENABLED (0) 74 75 static inline int preempt_count(void) 76 { 77 return READ_ONCE(S390_lowcore.preempt_count); 78 } 79 80 static inline void preempt_count_set(int pc) 81 { 82 S390_lowcore.preempt_count = pc; 83 } 84 85 static inline void set_preempt_need_resched(void) 86 { 87 } 88 89 static inline void clear_preempt_need_resched(void) 90 { 91 } 92 93 static inline bool test_preempt_need_resched(void) 94 { 95 return false; 96 } 97 98 static inline void __preempt_count_add(int val) 99 { 100 S390_lowcore.preempt_count += val; 101 } 102 103 static inline void __preempt_count_sub(int val) 104 { 105 S390_lowcore.preempt_count -= val; 106 } 107 108 static inline bool __preempt_count_dec_and_test(void) 109 { 110 return !--S390_lowcore.preempt_count && tif_need_resched(); 111 } 112 113 static inline bool should_resched(int preempt_offset) 114 { 115 return unlikely(preempt_count() == preempt_offset && 116 tif_need_resched()); 117 } 118 119 #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */ 120 121 #define init_task_preempt_count(p) do { } while (0) 122 /* Deferred to CPU bringup time */ 123 #define init_idle_preempt_count(p, cpu) do { } while (0) 124 125 #ifdef CONFIG_PREEMPTION 126 extern void preempt_schedule(void); 127 #define __preempt_schedule() preempt_schedule() 128 extern void preempt_schedule_notrace(void); 129 #define __preempt_schedule_notrace() preempt_schedule_notrace() 130 #endif /* CONFIG_PREEMPTION */ 131 132 #endif /* __ASM_PREEMPT_H */ 133