1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef __ASM_PREEMPT_H
 3#define __ASM_PREEMPT_H
 4
 5#include <linux/thread_info.h>
 6
 7#define PREEMPT_ENABLED	(0)
 8
 9static __always_inline int preempt_count(void)
10{
11	return READ_ONCE(current_thread_info()->preempt_count);
12}
13
14static __always_inline volatile int *preempt_count_ptr(void)
15{
16	return &current_thread_info()->preempt_count;
17}
18
19static __always_inline void preempt_count_set(int pc)
20{
21	*preempt_count_ptr() = pc;
22}
23
24/*
25 * must be macros to avoid header recursion hell
26 */
27#define init_task_preempt_count(p) do { \
28	task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
29} while (0)
30
31#define init_idle_preempt_count(p, cpu) do { \
32	task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
33} while (0)
34
35static __always_inline void set_preempt_need_resched(void)
36{
37}
38
39static __always_inline void clear_preempt_need_resched(void)
40{
41}
42
43static __always_inline bool test_preempt_need_resched(void)
44{
45	return false;
46}
47
48/*
49 * The various preempt_count add/sub methods
50 */
51
52static __always_inline void __preempt_count_add(int val)
53{
54	*preempt_count_ptr() += val;
55}
56
57static __always_inline void __preempt_count_sub(int val)
58{
59	*preempt_count_ptr() -= val;
60}
61
62static __always_inline bool __preempt_count_dec_and_test(void)
63{
64	/*
65	 * Because of load-store architectures cannot do per-cpu atomic
66	 * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
67	 * lost.
68	 */
69	return !--*preempt_count_ptr() && tif_need_resched();
70}
71
72/*
73 * Returns true when we need to resched and can (barring IRQ state).
74 */
75static __always_inline bool should_resched(int preempt_offset)
76{
77	return unlikely(preempt_count() == preempt_offset &&
78			tif_need_resched());
79}
80
81#ifdef CONFIG_PREEMPTION
82extern asmlinkage void preempt_schedule(void);
83#define __preempt_schedule() preempt_schedule()
84extern asmlinkage void preempt_schedule_notrace(void);
85#define __preempt_schedule_notrace() preempt_schedule_notrace()
86#endif /* CONFIG_PREEMPTION */
87
88#endif /* __ASM_PREEMPT_H */

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef __ASM_PREEMPT_H
 3#define __ASM_PREEMPT_H
 4
 5#include <linux/thread_info.h>
 6
 7#define PREEMPT_ENABLED	(0)
 8
 9static __always_inline int preempt_count(void)
10{
11	return READ_ONCE(current_thread_info()->preempt_count);
12}
13
14static __always_inline volatile int *preempt_count_ptr(void)
15{
16	return &current_thread_info()->preempt_count;
17}
18
19static __always_inline void preempt_count_set(int pc)
20{
21	*preempt_count_ptr() = pc;
22}
23
24/*
25 * must be macros to avoid header recursion hell
26 */
27#define init_task_preempt_count(p) do { \
28	task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
29} while (0)
30
31#define init_idle_preempt_count(p, cpu) do { \
32	task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
33} while (0)
34
35static __always_inline void set_preempt_need_resched(void)
36{
37}
38
39static __always_inline void clear_preempt_need_resched(void)
40{
41}
42
43static __always_inline bool test_preempt_need_resched(void)
44{
45	return false;
46}
47
48/*
49 * The various preempt_count add/sub methods
50 */
51
52static __always_inline void __preempt_count_add(int val)
53{
54	*preempt_count_ptr() += val;
55}
56
57static __always_inline void __preempt_count_sub(int val)
58{
59	*preempt_count_ptr() -= val;
60}
61
62static __always_inline bool __preempt_count_dec_and_test(void)
63{
64	/*
65	 * Because of load-store architectures cannot do per-cpu atomic
66	 * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
67	 * lost.
68	 */
69	return !--*preempt_count_ptr() && tif_need_resched();
70}
71
72/*
73 * Returns true when we need to resched and can (barring IRQ state).
74 */
75static __always_inline bool should_resched(int preempt_offset)
76{
77	return unlikely(preempt_count() == preempt_offset &&
78			tif_need_resched());
79}
80
81#ifdef CONFIG_PREEMPTION
82extern asmlinkage void preempt_schedule(void);
83#define __preempt_schedule() preempt_schedule()
84extern asmlinkage void preempt_schedule_notrace(void);
85#define __preempt_schedule_notrace() preempt_schedule_notrace()
86#endif /* CONFIG_PREEMPTION */
87
88#endif /* __ASM_PREEMPT_H */