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/* We use the MSB mostly because its available */
12#define PREEMPT_NEED_RESCHED 0x80000000
13#define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED)
14
15static inline int preempt_count(void)
16{
17 return READ_ONCE(S390_lowcore.preempt_count) & ~PREEMPT_NEED_RESCHED;
18}
19
20static 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
38static inline void set_preempt_need_resched(void)
39{
40 __atomic_and(~PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
41}
42
43static inline void clear_preempt_need_resched(void)
44{
45 __atomic_or(PREEMPT_NEED_RESCHED, &S390_lowcore.preempt_count);
46}
47
48static inline bool test_preempt_need_resched(void)
49{
50 return !(READ_ONCE(S390_lowcore.preempt_count) & PREEMPT_NEED_RESCHED);
51}
52
53static 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
61static inline void __preempt_count_sub(int val)
62{
63 __preempt_count_add(-val);
64}
65
66static inline bool __preempt_count_dec_and_test(void)
67{
68 return __atomic_add(-1, &S390_lowcore.preempt_count) == 1;
69}
70
71static 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
81static inline int preempt_count(void)
82{
83 return READ_ONCE(S390_lowcore.preempt_count);
84}
85
86static 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
97static inline void set_preempt_need_resched(void)
98{
99}
100
101static inline void clear_preempt_need_resched(void)
102{
103}
104
105static inline bool test_preempt_need_resched(void)
106{
107 return false;
108}
109
110static inline void __preempt_count_add(int val)
111{
112 S390_lowcore.preempt_count += val;
113}
114
115static inline void __preempt_count_sub(int val)
116{
117 S390_lowcore.preempt_count -= val;
118}
119
120static inline bool __preempt_count_dec_and_test(void)
121{
122 return !--S390_lowcore.preempt_count && tif_need_resched();
123}
124
125static 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_PREEMPTION
134extern asmlinkage void preempt_schedule(void);
135#define __preempt_schedule() preempt_schedule()
136extern asmlinkage void preempt_schedule_notrace(void);
137#define __preempt_schedule_notrace() preempt_schedule_notrace()
138#endif /* CONFIG_PREEMPTION */
139
140#endif /* __ASM_PREEMPT_H */