Linux kernel mirror (for testing)
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linux
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
13static inline int preempt_count(void)
14{
15 return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED;
16}
17
18static 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
36static inline void set_preempt_need_resched(void)
37{
38 __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
39}
40
41static inline void clear_preempt_need_resched(void)
42{
43 __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
44}
45
46static inline bool test_preempt_need_resched(void)
47{
48 return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED);
49}
50
51static 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
59static inline void __preempt_count_sub(int val)
60{
61 __preempt_count_add(-val);
62}
63
64static inline bool __preempt_count_dec_and_test(void)
65{
66 return __atomic_add(-1, &S390_lowcore.preempt_count) == 1;
67}
68
69static 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
79static inline int preempt_count(void)
80{
81 return READ_ONCE(S390_lowcore.preempt_count);
82}
83
84static 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
95static inline void set_preempt_need_resched(void)
96{
97}
98
99static inline void clear_preempt_need_resched(void)
100{
101}
102
103static inline bool test_preempt_need_resched(void)
104{
105 return false;
106}
107
108static inline void __preempt_count_add(int val)
109{
110 S390_lowcore.preempt_count += val;
111}
112
113static inline void __preempt_count_sub(int val)
114{
115 S390_lowcore.preempt_count -= val;
116}
117
118static inline bool __preempt_count_dec_and_test(void)
119{
120 return !--S390_lowcore.preempt_count && tif_need_resched();
121}
122
123static 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
132extern asmlinkage void preempt_schedule(void);
133#define __preempt_schedule() preempt_schedule()
134extern asmlinkage void preempt_schedule_notrace(void);
135#define __preempt_schedule_notrace() preempt_schedule_notrace()
136#endif /* CONFIG_PREEMPT */
137
138#endif /* __ASM_PREEMPT_H */