Rev 5272 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 5272 | serge | 1 | #ifndef __ASM_PREEMPT_H |
| 2 | #define __ASM_PREEMPT_H |
||
| 3 | |||
| 4 | #include |
||
| 5 | #include |
||
| 6 | //#include |
||
| 7 | |||
| 8 | DECLARE_PER_CPU(int, __preempt_count); |
||
| 9 | |||
| 10 | /* |
||
| 11 | * We use the PREEMPT_NEED_RESCHED bit as an inverted NEED_RESCHED such |
||
| 12 | * that a decrement hitting 0 means we can and should reschedule. |
||
| 13 | */ |
||
| 14 | #define PREEMPT_ENABLED (0 + PREEMPT_NEED_RESCHED) |
||
| 15 | |||
| 16 | /* |
||
| 17 | * We mask the PREEMPT_NEED_RESCHED bit so as not to confuse all current users |
||
| 18 | * that think a non-zero value indicates we cannot preempt. |
||
| 19 | */ |
||
| 20 | static __always_inline int preempt_count(void) |
||
| 21 | { |
||
| 22 | return raw_cpu_read_4(__preempt_count) & ~PREEMPT_NEED_RESCHED; |
||
| 23 | } |
||
| 24 | |||
| 25 | static __always_inline void preempt_count_set(int pc) |
||
| 26 | { |
||
| 27 | raw_cpu_write_4(__preempt_count, pc); |
||
| 28 | } |
||
| 29 | |||
| 30 | /* |
||
| 31 | * must be macros to avoid header recursion hell |
||
| 32 | */ |
||
| 6082 | serge | 33 | #define init_task_preempt_count(p) do { } while (0) |
| 5272 | serge | 34 | |
| 35 | #define init_idle_preempt_count(p, cpu) do { \ |
||
| 36 | per_cpu(__preempt_count, (cpu)) = PREEMPT_ENABLED; \ |
||
| 37 | } while (0) |
||
| 38 | |||
| 39 | /* |
||
| 40 | * We fold the NEED_RESCHED bit into the preempt count such that |
||
| 41 | * preempt_enable() can decrement and test for needing to reschedule with a |
||
| 42 | * single instruction. |
||
| 43 | * |
||
| 44 | * We invert the actual bit, so that when the decrement hits 0 we know we both |
||
| 45 | * need to resched (the bit is cleared) and can resched (no preempt count). |
||
| 46 | */ |
||
| 47 | |||
| 48 | static __always_inline void set_preempt_need_resched(void) |
||
| 49 | { |
||
| 50 | raw_cpu_and_4(__preempt_count, ~PREEMPT_NEED_RESCHED); |
||
| 51 | } |
||
| 52 | |||
| 53 | static __always_inline void clear_preempt_need_resched(void) |
||
| 54 | { |
||
| 55 | raw_cpu_or_4(__preempt_count, PREEMPT_NEED_RESCHED); |
||
| 56 | } |
||
| 57 | |||
| 58 | static __always_inline bool test_preempt_need_resched(void) |
||
| 59 | { |
||
| 60 | return !(raw_cpu_read_4(__preempt_count) & PREEMPT_NEED_RESCHED); |
||
| 61 | } |
||
| 62 | |||
| 63 | /* |
||
| 64 | * The various preempt_count add/sub methods |
||
| 65 | */ |
||
| 66 | |||
| 67 | static __always_inline void __preempt_count_add(int val) |
||
| 68 | { |
||
| 69 | raw_cpu_add_4(__preempt_count, val); |
||
| 70 | } |
||
| 71 | |||
| 72 | static __always_inline void __preempt_count_sub(int val) |
||
| 73 | { |
||
| 74 | raw_cpu_add_4(__preempt_count, -val); |
||
| 75 | } |
||
| 76 | |||
| 77 | /* |
||
| 78 | * Because we keep PREEMPT_NEED_RESCHED set when we do _not_ need to reschedule |
||
| 79 | * a decrement which hits zero means we have no preempt_count and should |
||
| 80 | * reschedule. |
||
| 81 | */ |
||
| 82 | static __always_inline bool __preempt_count_dec_and_test(void) |
||
| 83 | { |
||
| 84 | GEN_UNARY_RMWcc("decl", __preempt_count, __percpu_arg(0), "e"); |
||
| 85 | } |
||
| 86 | |||
| 87 | /* |
||
| 88 | * Returns true when we need to resched and can (barring IRQ state). |
||
| 89 | */ |
||
| 6082 | serge | 90 | static __always_inline bool should_resched(int preempt_offset) |
| 5272 | serge | 91 | { |
| 6082 | serge | 92 | return unlikely(raw_cpu_read_4(__preempt_count) == preempt_offset); |
| 5272 | serge | 93 | } |
| 94 | |||
| 95 | #ifdef CONFIG_PREEMPT |
||
| 96 | extern asmlinkage void ___preempt_schedule(void); |
||
| 97 | # define __preempt_schedule() asm ("call ___preempt_schedule") |
||
| 98 | extern asmlinkage void preempt_schedule(void); |
||
| 6082 | serge | 99 | extern asmlinkage void ___preempt_schedule_notrace(void); |
| 100 | # define __preempt_schedule_notrace() asm ("call ___preempt_schedule_notrace") |
||
| 101 | extern asmlinkage void preempt_schedule_notrace(void); |
||
| 5272 | serge | 102 | #endif |
| 103 | |||
| 104 | #endif /* __ASM_PREEMPT_H */ |