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feat/kernel: Did some lapic stuff

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This commit is contained in:
Kevin Alavik 2025-05-31 18:19:56 +02:00
parent d5371bcbb2
commit 01e2f6a3d8
Signed by: cmpsb
GPG key ID: 10D1CC0526FDC6D7
7 changed files with 193 additions and 91 deletions
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72
kernel/src/sys/apic/lapic.c
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@ -1,43 +1,75 @@
/* EMK 1.0 Copyright (c) 2025 Piraterna */
#include <sys/apic/lapic.h>
#include <arch/cpu.h>
#include <sys/acpi/madt.h>
#include <arch/paging.h>
#include <util/log.h>
#include <mm/vmm.h>
#include <stdatomic.h>
#include <sys/kpanic.h>
atomic_uintptr_t lapic_msr = 0;
volatile uint64_t *lapic_base = 0;
atomic_uintptr_t lapic_base_atomic = 0;
#define LAPIC_BASE ((volatile uint32_t *)atomic_load(&lapic_base_atomic))
void lapic_write(uint32_t offset, uint32_t value)
{
if (!lapic_base)
volatile uint32_t *base = LAPIC_BASE;
if (!base)
{
log_early("warning: LAPIC not initialized!");
return;
log_early("error: LAPIC not initialized!");
kpanic(NULL, "LAPIC write attempted before initialization");
}
volatile uint32_t *reg = (volatile uint32_t *)((uint8_t *)lapic_base + offset);
atomic_store((_Atomic uint32_t *)reg, value);
base[offset / 4] = value;
}
uint32_t lapic_read(uint32_t offset)
{
if (!lapic_base)
volatile uint32_t *base = LAPIC_BASE;
if (!base)
{
log_early("warning: LAPIC not initialized!");
log_early("error: LAPIC not initialized!");
return 0;
}
volatile uint32_t *reg = (volatile uint32_t *)((uint8_t *)lapic_base + offset);
return atomic_load((_Atomic uint32_t *)reg);
return base[offset / 4];
}
void lapic_init()
void lapic_init(void)
{
uint64_t msr = rdmsr(LAPIC_BASE);
uint64_t msr = rdmsr(LAPIC_BASE_MSR);
msr |= (1 << 11); // Set global LAPIC enable bit
wrmsr(LAPIC_BASE_MSR, msr);
atomic_store(&lapic_msr, msr);
lapic_base = (volatile uint64_t *)(msr & ~(0xffff));
atomic_store(&lapic_addr, (uint64_t)lapic_base);
log_early("New LAPIC base: 0x%lx", lapic_base);
}
uint64_t phys_addr = msr & ~0xFFFULL;
uint64_t virt_addr = (uint64_t)HIGHER_HALF(phys_addr);
int ret = vmap(pmget(), virt_addr, phys_addr, VMM_PRESENT | VMM_WRITE | VMM_NX);
if (ret != 0)
{
log_early("error: Failed to map LAPIC base 0x%lx to 0x%lx", phys_addr, virt_addr);
kpanic(NULL, "LAPIC mapping failed");
}
atomic_store(&lapic_base_atomic, virt_addr);
atomic_store(&lapic_addr, virt_addr);
}
void lapic_enable(void)
{
volatile uint32_t *base = LAPIC_BASE;
if (!base)
{
log_early("warning: lapic_enable called before lapic_init");
return;
}
uint32_t svr = lapic_read(LAPIC_SVR);
svr |= (1 << 8); // Enable APIC
svr &= ~(1 << 9); // Disable focus processor checking
svr = (svr & ~0xFF) | 0xFF; // Set spurious interrupt vector to 0xFF
lapic_write(LAPIC_SVR, svr);
lapic_write(LAPIC_TPR, 0);
uint32_t id = lapic_read(LAPIC_ID) >> 24;
log_early("LAPIC enabled and initialized for CPU %u", id);
}