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| 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 | |
| 9 | static __always_inline int preempt_count(void) |
| 10 | { |
| 11 | return READ_ONCE(current_thread_info()->preempt_count); |
| 12 | } |
| 13 | |
| 14 | static __always_inline volatile int *preempt_count_ptr(void) |
| 15 | { |
| 16 | return ¤t_thread_info()->preempt_count; |
| 17 | } |
| 18 | |
| 19 | static __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 | |
| 35 | static __always_inline void set_preempt_need_resched(void) |
| 36 | { |
| 37 | } |
| 38 | |
| 39 | static __always_inline void clear_preempt_need_resched(void) |
| 40 | { |
| 41 | } |
| 42 | |
| 43 | static __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 | |
| 52 | static __always_inline void __preempt_count_add(int val) |
| 53 | { |
| 54 | *preempt_count_ptr() += val; |
| 55 | } |
| 56 | |
| 57 | static __always_inline void __preempt_count_sub(int val) |
| 58 | { |
| 59 | *preempt_count_ptr() -= val; |
| 60 | } |
| 61 | |
| 62 | static __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 | */ |
| 75 | static __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 |
| 82 | extern asmlinkage void preempt_schedule(void); |
| 83 | extern asmlinkage void preempt_schedule_notrace(void); |
| 84 | |
| 85 | #if defined(CONFIG_PREEMPT_DYNAMIC) && defined(CONFIG_HAVE_PREEMPT_DYNAMIC_KEY) |
| 86 | |
| 87 | void dynamic_preempt_schedule(void); |
| 88 | void dynamic_preempt_schedule_notrace(void); |
| 89 | #define __preempt_schedule() dynamic_preempt_schedule() |
| 90 | #define __preempt_schedule_notrace() dynamic_preempt_schedule_notrace() |
| 91 | |
| 92 | #else /* !CONFIG_PREEMPT_DYNAMIC || !CONFIG_HAVE_PREEMPT_DYNAMIC_KEY*/ |
| 93 | |
| 94 | #define __preempt_schedule() preempt_schedule() |
| 95 | #define __preempt_schedule_notrace() preempt_schedule_notrace() |
| 96 | |
| 97 | #endif /* CONFIG_PREEMPT_DYNAMIC && CONFIG_HAVE_PREEMPT_DYNAMIC_KEY*/ |
| 98 | #endif /* CONFIG_PREEMPTION */ |
| 99 | |
| 100 | #endif /* __ASM_PREEMPT_H */ |
| 101 |
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