| 1 |
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| 2 | #ifndef __ASM_PREEMPT_H
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| 3 | #define __ASM_PREEMPT_H
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| 4 |
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| 5 | #include <linux/thread_info.h>
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| 6 |
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| 7 | #define PREEMPT_ENABLED (0)
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| 8 |
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| 9 | static __always_inline int preempt_count(void)
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| 10 | {
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| 11 | return READ_ONCE(current_thread_info()->preempt_count);
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| 12 | }
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| 13 |
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| 14 | static __always_inline volatile int *preempt_count_ptr(void)
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| 15 | {
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| 16 | return ¤t_thread_info()->preempt_count;
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| 17 | }
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| 18 |
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| 19 | static __always_inline void preempt_count_set(int pc)
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| 20 | {
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| 21 | *preempt_count_ptr() = pc;
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| 22 | }
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| 23 |
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| 24 | |
| 25 | * must be macros to avoid header recursion hell
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| 26 |
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| 27 | #define init_task_preempt_count(p) do { \
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| 28 | task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \
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| 29 | } while (0)
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| 30 |
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| 31 | #define init_idle_preempt_count(p, cpu) do { \
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| 32 | task_thread_info(p)->preempt_count = PREEMPT_DISABLED; \
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| 33 | } while (0)
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| 34 |
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| 35 | static __always_inline void set_preempt_need_resched(void)
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| 36 | {
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| 37 | }
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| 38 |
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| 39 | static __always_inline void clear_preempt_need_resched(void)
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| 40 | {
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| 41 | }
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| 42 |
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| 43 | static __always_inline bool test_preempt_need_resched(void)
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| 44 | {
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| 45 | return false;
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| 46 | }
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| 47 |
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| 48 | |
| 49 | * The various preempt_count add/sub methods
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| 50 |
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| 51 |
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| 52 | static __always_inline void __preempt_count_add(int val)
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| 53 | {
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| 54 | *preempt_count_ptr() += val;
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| 55 | }
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| 56 |
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| 57 | static __always_inline void __preempt_count_sub(int val)
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| 58 | {
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| 59 | *preempt_count_ptr() -= val;
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| 60 | }
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| 61 |
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| 62 | static __always_inline int __preempt_count_add_return(int val)
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| 63 | {
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| 64 | *preempt_count_ptr() += val;
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| 65 |
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| 66 | return *preempt_count_ptr();
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| 67 | }
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| 68 |
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| 69 | static __always_inline int __preempt_count_sub_return(int val)
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| 70 | {
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| 71 | *preempt_count_ptr() -= val;
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| 72 |
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| 73 | return *preempt_count_ptr();
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| 74 | }
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| 75 |
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| 76 | static __always_inline bool __preempt_count_dec_and_test(void)
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| 77 | {
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| 78 | |
| 79 | * Because of load-store architectures cannot do per-cpu atomic
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| 80 | * operations; we cannot use PREEMPT_NEED_RESCHED because it might get
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| 81 | * lost.
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| 82 |
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| 83 | return !--*preempt_count_ptr() && tif_need_resched();
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| 84 | }
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| 85 |
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| 86 | |
| 87 | * Returns true when we need to resched and can (barring IRQ state).
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| 88 |
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| 89 | static __always_inline bool should_resched(int preempt_offset)
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| 90 | {
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| 91 | return unlikely(preempt_count() == preempt_offset &&
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| 92 | tif_need_resched());
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| 93 | }
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| 94 |
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| 95 | #ifdef CONFIG_PREEMPTION
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| 96 | extern asmlinkage void preempt_schedule(void);
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| 97 | extern asmlinkage void preempt_schedule_notrace(void);
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| 98 |
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| 99 | #define __preempt_schedule() preempt_schedule()
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| 100 | #define __preempt_schedule_notrace() preempt_schedule_notrace()
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| 101 |
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| 102 | #endif
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| 103 |
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| 104 | #endif
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