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path: root/kernel/src/apic/apic.c
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#include <atomic.h>
#include <paging.h>
#include <libk/stdio.h>
#include <apic.h>
#include <ioapic.h>
#include <madt.h>
#include <timer.h>

mutex_t cnt_lock;
uint32_t ap_cnt = 0;
uint32_t bspdone = 0;
uint32_t ioapic_addr = 0;
uint64_t lapic_addr = 0;
uint32_t numcores = 0;
uint8_t cpu_apic_ids[256];

uint8_t curr_cpu_apic_id()
{
	return (uint8_t)(((*((__volatile__ uint32_t *)((uint64_t)lapic_addr +
						       0x20))) >>
			  24) &
			 0xFF);
}

void init_ap_cpus()
{
	uint8_t bspid = curr_cpu_apic_id();

	init_mutex(&cnt_lock);
	map_addr(lapic_addr, lapic_addr, FLAG_PRESENT);

	for (size_t i = 0; i < numcores; i++) {
		// do not start BSP, that's already running this code
		if (cpu_apic_ids[i] == bspid)
			continue;

		// send INIT IPI

		// clear APIC errors
		*((__volatile__ uint32_t *)(lapic_addr + 0x280)) = 0;
		// select AP
		*((__volatile__ uint32_t *)(lapic_addr + 0x310)) =
			(*((__volatile__ uint32_t *)(lapic_addr + 0x310)) &
			 0x00ffffff) |
			((uint32_t)cpu_apic_ids[i] << 24);
		// trigger INIT IPI
		*((__volatile__ uint32_t *)(lapic_addr + 0x300)) =
			(*((__volatile__ uint32_t *)(lapic_addr + 0x300)) &
			 0xfff00000) |
			0x00C500;
		// wait for delivery
		do {
			__asm__ __volatile__("pause" : : : "memory");
		} while (*((__volatile__ uint32_t *)(uint64_t)(lapic_addr +
							       0x300)) &
			 (1 << 12));
		// select AP
		*((__volatile__ uint32_t *)(lapic_addr + 0x310)) =
			(*((__volatile__ uint32_t *)(lapic_addr + 0x310)) &
			 0x00ffffff) |
			((uint32_t)cpu_apic_ids[i] << 24);
		// deassert
		*((__volatile__ uint32_t *)(lapic_addr + 0x300)) =
			(*((__volatile__ uint32_t *)(lapic_addr + 0x300)) &
			 0xfff00000) |
			0x008500;
		// wait for delivery
		do {
			__asm__ __volatile__("pause" : : : "memory");
		} while (*((__volatile__ uint32_t *)(uint64_t)(lapic_addr +
							       0x300)) &
			 (1 << 12));
		// wait 10 msec
		wait(10);

		// send STARTUP IPI (twice)

		for (size_t j = 0; j < 2; j++) {
			// clear APIC errors
			*((__volatile__ uint32_t *)(lapic_addr + 0x280)) = 0;
			// select AP
			*((__volatile__ uint32_t *)(lapic_addr + 0x310)) =
				(*((__volatile__ uint32_t *)(lapic_addr +
							     0x310)) &
				 0x00ffffff) |
				((uint32_t)cpu_apic_ids[i] << 24);
			// trigger STARTUP IPI for 0800:0000
			*((__volatile__ uint32_t *)(lapic_addr + 0x300)) =
				(*((__volatile__ uint32_t *)(lapic_addr +
							     0x300)) &
				 0xfff0f800) |
				0x000608;
			// wait 200 usec
			wait(1);
			// wait for delivery
			do {
				__asm__ __volatile__("pause" : : : "memory");
			} while (*((__volatile__ uint32_t
					    *)(uint64_t)(lapic_addr + 0x300)) &
				 (1 << 12));
		}
	}

	bspdone = 1;
	wait(10);
	printf("ap_cnt: %d\n", ap_cnt);
}