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Peter Zijlstraa7878702013-08-14 14:55:40 +02001#ifndef __ASM_PREEMPT_H
2#define __ASM_PREEMPT_H
3
4#include <linux/thread_info.h>
5
Peter Zijlstraba1f14f2013-11-28 14:26:41 +01006#define PREEMPT_ENABLED (0)
7
Peter Zijlstraa7878702013-08-14 14:55:40 +02008static __always_inline int preempt_count(void)
9{
Peter Zijlstraba1f14f2013-11-28 14:26:41 +010010 return current_thread_info()->preempt_count;
Peter Zijlstraa7878702013-08-14 14:55:40 +020011}
12
13static __always_inline int *preempt_count_ptr(void)
14{
15 return &current_thread_info()->preempt_count;
16}
17
Peter Zijlstraa7878702013-08-14 14:55:40 +020018static __always_inline void preempt_count_set(int pc)
19{
20 *preempt_count_ptr() = pc;
21}
22
23/*
Peter Zijlstra01028742013-08-14 14:55:46 +020024 * must be macros to avoid header recursion hell
25 */
Peter Zijlstra01028742013-08-14 14:55:46 +020026#define init_task_preempt_count(p) do { \
27 task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
28} while (0)
29
30#define init_idle_preempt_count(p, cpu) do { \
31 task_thread_info(p)->preempt_count = PREEMPT_ENABLED; \
32} while (0)
33
Peter Zijlstraa7878702013-08-14 14:55:40 +020034static __always_inline void set_preempt_need_resched(void)
35{
Peter Zijlstraa7878702013-08-14 14:55:40 +020036}
37
38static __always_inline void clear_preempt_need_resched(void)
39{
Peter Zijlstraa7878702013-08-14 14:55:40 +020040}
41
42static __always_inline bool test_preempt_need_resched(void)
43{
Peter Zijlstraba1f14f2013-11-28 14:26:41 +010044 return false;
Peter Zijlstraa7878702013-08-14 14:55:40 +020045}
46
Peter Zijlstrabdb43802013-09-10 12:15:23 +020047/*
48 * The various preempt_count add/sub methods
49 */
50
51static __always_inline void __preempt_count_add(int val)
52{
53 *preempt_count_ptr() += val;
54}
55
56static __always_inline void __preempt_count_sub(int val)
57{
58 *preempt_count_ptr() -= val;
59}
60
61static __always_inline bool __preempt_count_dec_and_test(void)
62{
Peter Zijlstraba1f14f2013-11-28 14:26:41 +010063 /*
64 * Because of load-store architectures cannot do per-cpu atomic
65 * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
66 * lost.
67 */
68 return !--*preempt_count_ptr() && tif_need_resched();
Peter Zijlstrabdb43802013-09-10 12:15:23 +020069}
70
71/*
Peter Zijlstrabdb43802013-09-10 12:15:23 +020072 * Returns true when we need to resched and can (barring IRQ state).
73 */
Konstantin Khlebnikovfe32d3c2015-07-15 12:52:04 +030074static __always_inline bool should_resched(int preempt_offset)
Peter Zijlstrabdb43802013-09-10 12:15:23 +020075{
Konstantin Khlebnikovfe32d3c2015-07-15 12:52:04 +030076 return unlikely(preempt_count() == preempt_offset &&
77 tif_need_resched());
Peter Zijlstrabdb43802013-09-10 12:15:23 +020078}
79
Peter Zijlstra1a338ac2013-08-14 14:51:00 +020080#ifdef CONFIG_PREEMPT
81extern asmlinkage void preempt_schedule(void);
82#define __preempt_schedule() preempt_schedule()
Frederic Weisbecker4eaca0a2015-06-04 17:39:08 +020083extern asmlinkage void preempt_schedule_notrace(void);
84#define __preempt_schedule_notrace() preempt_schedule_notrace()
Peter Zijlstra1a338ac2013-08-14 14:51:00 +020085#endif /* CONFIG_PREEMPT */
86
Peter Zijlstraa7878702013-08-14 14:55:40 +020087#endif /* __ASM_PREEMPT_H */