APIC 学习资料整理

apic

• https://habr.com/en/post/446312/

// global apic variable
struct apic *apic __ro_after_init = &apic_flat;

• apic, timer and LVIT
  • what’s LVIT ? ```c /* 进入到 arch/x86/kernel/apic/apic.c 了 */ // 好吧，就是向 apic 控制器写入寄存器之类的操作 !

/*

• The local apic timer can be used for any function which is CPU local. */ static struct clock_event_device lapic_clockevent = { .name = “lapic”, .features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT | CLOCK_EVT_FEAT_C3STOP | CLOCK_EVT_FEAT_DUMMY, .shift = 32, .set_state_shutdown = lapic_timer_shutdown, .set_state_periodic = lapic_timer_set_periodic, .set_state_oneshot = lapic_timer_set_oneshot, .set_state_oneshot_stopped = lapic_timer_shutdown, .set_next_event = lapic_next_event, .broadcast = lapic_timer_broadcast, .rating = 100, .irq = -1, };

static int lapic_timer_set_oneshot(struct clock_event_device *evt) { return lapic_timer_set_periodic_oneshot(evt, true); }

static inline int lapic_timer_set_periodic_oneshot(struct clock_event_device evt, bool oneshot) { / Lapic used as dummy for broadcast ? */ if (evt->features & CLOCK_EVT_FEAT_DUMMY) return 0;

__setup_APIC_LVTT(lapic_timer_period, oneshot, 1);
return 0; } ```

apic_intr_mode_select

APIC 可以有多个模式，通过内核配置，来模拟 pic 模式的

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