1 #ifndef __ASM_PREEMPT_H 2 #define __ASM_PREEMPT_H 3 4 #include <linux/thread_info.h> 5 6 #define PREEMPT_ENABLED (0) 7 8 static __always_inline int preempt_count(void) 9 { 10 return READ_ONCE(current_thread_info()->preempt_count); 11 } 12 13 static __always_inline volatile int *preempt_count_ptr(void) 14 { 15 return ¤t_thread_info()->preempt_count; 16 } 17 18 static __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 init_task_preempt_count(p) do { \ 27 task_thread_info(p)->preempt_count = FORK_PREEMPT_COUNT; \ 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 34 static __always_inline void set_preempt_need_resched(void) 35 { 36 } 37 38 static __always_inline void clear_preempt_need_resched(void) 39 { 40 } 41 42 static __always_inline bool test_preempt_need_resched(void) 43 { 44 return false; 45 } 46 47 /* 48 * The various preempt_count add/sub methods 49 */ 50 51 static __always_inline void __preempt_count_add(int val) 52 { 53 *preempt_count_ptr() += val; 54 } 55 56 static __always_inline void __preempt_count_sub(int val) 57 { 58 *preempt_count_ptr() -= val; 59 } 60 61 static __always_inline bool __preempt_count_dec_and_test(void) 62 { 63 /* 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(); 69 } 70 71 /* 72 * Returns true when we need to resched and can (barring IRQ state). 73 */ 74 static __always_inline bool should_resched(int preempt_offset) 75 { 76 return unlikely(preempt_count() == preempt_offset && 77 tif_need_resched()); 78 } 79 80 #ifdef CONFIG_PREEMPT 81 extern asmlinkage void preempt_schedule(void); 82 #define __preempt_schedule() preempt_schedule() 83 extern asmlinkage void preempt_schedule_notrace(void); 84 #define __preempt_schedule_notrace() preempt_schedule_notrace() 85 #endif /* CONFIG_PREEMPT */ 86 87 #endif /* __ASM_PREEMPT_H */ 88