Linux kernel mirror (for testing)
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linux
1#ifndef __ASM_PREEMPT_H
2#define __ASM_PREEMPT_H
3
4#include <linux/thread_info.h>
5
6#define PREEMPT_ENABLED (0)
7
8static __always_inline int preempt_count(void)
9{
10 return current_thread_info()->preempt_count;
11}
12
13static __always_inline int *preempt_count_ptr(void)
14{
15 return ¤t_thread_info()->preempt_count;
16}
17
18static __always_inline void preempt_count_set(int pc)
19{
20 *preempt_count_ptr() = pc;
21}
22
23/*
24 * must be macros to avoid header recursion hell
25 */
26#define task_preempt_count(p) \
27 (task_thread_info(p)->preempt_count & ~PREEMPT_NEED_RESCHED)
28
29#define init_task_preempt_count(p) do { \
30 task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
31} while (0)
32
33#define init_idle_preempt_count(p, cpu) do { \
34 task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
35} while (0)
36
37static __always_inline void set_preempt_need_resched(void)
38{
39}
40
41static __always_inline void clear_preempt_need_resched(void)
42{
43}
44
45static __always_inline bool test_preempt_need_resched(void)
46{
47 return false;
48}
49
50/*
51 * The various preempt_count add/sub methods
52 */
53
54static __always_inline void __preempt_count_add(int val)
55{
56 *preempt_count_ptr() += val;
57}
58
59static __always_inline void __preempt_count_sub(int val)
60{
61 *preempt_count_ptr() -= val;
62}
63
64static __always_inline bool __preempt_count_dec_and_test(void)
65{
66 /*
67 * Because of load-store architectures cannot do per-cpu atomic
68 * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
69 * lost.
70 */
71 return !--*preempt_count_ptr() && tif_need_resched();
72}
73
74/*
75 * Returns true when we need to resched and can (barring IRQ state).
76 */
77static __always_inline bool should_resched(void)
78{
79 return unlikely(!preempt_count() && tif_need_resched());
80}
81
82#ifdef CONFIG_PREEMPT
83extern asmlinkage void preempt_schedule(void);
84#define __preempt_schedule() preempt_schedule()
85
86#ifdef CONFIG_CONTEXT_TRACKING
87extern asmlinkage void preempt_schedule_context(void);
88#define __preempt_schedule_context() preempt_schedule_context()
89#endif
90#endif /* CONFIG_PREEMPT */
91
92#endif /* __ASM_PREEMPT_H */