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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 | /* SPDX-License-Identifier: GPL-2.0 */ #ifndef __ASM_PREEMPT_H #define __ASM_PREEMPT_H #include <asm/current.h> #include <linux/thread_info.h> #include <asm/atomic_ops.h> #ifdef CONFIG_HAVE_MARCH_Z196_FEATURES /* We use the MSB mostly because its available */ #define PREEMPT_NEED_RESCHED 0x80000000 #define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED) static inline int preempt_count(void) { return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED; } static inline void preempt_count_set(int pc) { int old, new; do { old = READ_ONCE(S390_lowcore.preempt_count); new = (old & PREEMPT_NEED_RESCHED) | (pc & ~PREEMPT_NEED_RESCHED); } while (__atomic_cmpxchg(&S390_lowcore.preempt_count, old, new) != old); } static inline void set_preempt_need_resched(void) { __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count); } static inline void clear_preempt_need_resched(void) { __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count); } static inline bool test_preempt_need_resched(void) { return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED); } static inline void __preempt_count_add(int val) { /* * With some obscure config options and CONFIG_PROFILE_ALL_BRANCHES * enabled, gcc 12 fails to handle __builtin_constant_p(). */ if (!IS_ENABLED(CONFIG_PROFILE_ALL_BRANCHES)) { if (__builtin_constant_p(val) && (val >= -128) && (val <= 127)) { __atomic_add_const(val, &S390_lowcore.preempt_count); return; } } __atomic_add(val, &S390_lowcore.preempt_count); } static inline void __preempt_count_sub(int val) { __preempt_count_add(-val); } static inline bool __preempt_count_dec_and_test(void) { return __atomic_add(-1, &S390_lowcore.preempt_count) == 1; } static inline bool should_resched(int preempt_offset) { return unlikely(READ_ONCE(S390_lowcore.preempt_count) == preempt_offset); } #else /* CONFIG_HAVE_MARCH_Z196_FEATURES */ #define PREEMPT_ENABLED (0) static inline int preempt_count(void) { return READ_ONCE(S390_lowcore.preempt_count); } static inline void preempt_count_set(int pc) { S390_lowcore.preempt_count = pc; } static inline void set_preempt_need_resched(void) { } static inline void clear_preempt_need_resched(void) { } static inline bool test_preempt_need_resched(void) { return false; } static inline void __preempt_count_add(int val) { S390_lowcore.preempt_count += val; } static inline void __preempt_count_sub(int val) { S390_lowcore.preempt_count -= val; } static inline bool __preempt_count_dec_and_test(void) { return !--S390_lowcore.preempt_count && tif_need_resched(); } static inline bool should_resched(int preempt_offset) { return unlikely(preempt_count() == preempt_offset && tif_need_resched()); } #endif /* CONFIG_HAVE_MARCH_Z196_FEATURES */ #define init_task_preempt_count(p) do { } while (0) /* Deferred to CPU bringup time */ #define init_idle_preempt_count(p, cpu) do { } while (0) #ifdef CONFIG_PREEMPTION extern void preempt_schedule(void); #define __preempt_schedule() preempt_schedule() extern void preempt_schedule_notrace(void); #define __preempt_schedule_notrace() preempt_schedule_notrace() #endif /* CONFIG_PREEMPTION */ #endif /* __ASM_PREEMPT_H */ |