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Added missing vectors

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This commit is contained in:
Pierre-Emmanuel Gob. 2026-09-18 20:31:46 +02:00
parent 29c79f20c2
commit 830613ccb6
2 changed files with 75 additions and 4 deletions
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50
kernel/arch/x86_64/idt.c
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@ -4,14 +4,17 @@
* (kernel code selector 0x18). Privileged primitive: `lidt` in
* idt_init(). Fault behavior: before idt_init() any fault
* triple-faults; after, vectors 0-31 print diagnostics and halt.
* Vectors 32-255 stay not-present until the PIC is remapped.
* IF stays cleared; exceptions fire regardless of IF.
* Vectors 32-47 stay not-present until pic_remap() +
* idt_install_irqs() install the IRQ gates; vectors 48-255 stay
* not-present (no APIC yet). IF stays cleared; exceptions fire
* regardless of IF, IRQs only after the integrator runs `sti`.
*/
#include <stdint.h>
#include "console.h"
#include "idt.h"
#include "pic.h"
/* 64-bit interrupt gate descriptor (Intel SDM Vol. 3, IDT gate). */
struct idt_entry {
@ -42,6 +45,14 @@ static struct idtr idtr;
/* Stub addresses from isr.asm, one per exception vector 0-31. */
extern uint64_t isr_stub_table[IDT_EXCEPTION_COUNT];
/* Stub addresses from isr.asm, one per remapped IRQ vector 32-47. */
extern uint64_t irq_stub_table[IDT_IRQ_COUNT];
/* Per-IRQ handlers for lines 0-15; NULL means "EOI only".
* WHY a plain table: one subsystem per file — device drivers own
* their logic and only register a callback here. BSS-zeroed. */
static void (*irq_handlers[IDT_IRQ_COUNT])(void);
/* Install one gate: handler address + segment + IST index + flags. */
static void idt_set_gate(uint8_t vector, uint64_t handler, uint16_t selector,
uint8_t ist, uint8_t flags)
@ -86,6 +97,41 @@ void idt_init(void)
__asm__ volatile("lidt %0" ::"m"(idtr) : "memory");
}
void idt_install_irqs(void)
{
for (uint16_t i = 0; i < IDT_IRQ_COUNT; i++) {
idt_set_gate((uint8_t)(IDT_IRQ_BASE + i), irq_stub_table[i],
KERNEL_CS, 0, IDT_FLAG_PRESENT_INT);
}
}
void irq_register_handler(uint8_t irq, void (*handler)(void))
{
if (irq >= IDT_IRQ_COUNT) {
return;
}
irq_handlers[irq] = handler;
}
void irq_dispatch(struct interrupt_frame *frame)
{
uint64_t vector = frame->vector;
uint8_t irq;
if (vector < IDT_IRQ_BASE || vector >= IDT_IRQ_BASE + IDT_IRQ_COUNT) {
return;
}
irq = (uint8_t)(vector - IDT_IRQ_BASE);
/* WHY handler before EOI: the EOI re-arms the (edge-triggered) PIC
* line, so acking first would let the same IRQ re-enter before the
* driver finished. A NULL slot just gets an EOI. */
if (irq_handlers[irq] != 0) {
irq_handlers[irq]();
}
pic_eoi(irq);
}
void exception_handler(struct interrupt_frame *frame)
{
uint64_t vector = frame->vector;