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add: idt

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This commit is contained in:
Starnakin 2024-10-02 14:15:57 +02:00
parent a3bbffcfd9
commit 8b2d35594d
5 changed files with 57 additions and 25 deletions
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11
headers/idt.h
View File

@ -6,4 +6,15 @@ struct idt_descriptor {
uint32_t offset;
} __attribute__((packed));
struct idt_entry {
uint16_t isr_low; // The lower 16 bits of the ISR's address
uint16_t kernel_cs; // The GDT segment selector that the CPU will load
// into CS before calling the ISR
uint8_t reserved; // Set to zero
uint8_t attributes; // Type and attributes; see the IDT page
uint16_t isr_high; // The higher 16 bits of the ISR's address
} __attribute__((packed));
#define IDT_SIZE 256
void init_idt(void);

2
src/interrupt/handler.c
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@ -3,6 +3,8 @@
#include <stdint.h>
__attribute__((noreturn)) void exception_handler(void);
void exception_handler(void)
{
int8_t index = -1;

43
src/interrupt/idt.c
View File

@ -1,36 +1,59 @@
#include <stdbool.h>
#include <stdint.h>
#include "gdt.h"
#include "idt.h"
uint16_t idt_entries[IDT_SIZE * 4];
struct idt_descriptor idtr;
extern void *isr_stub_table[];
__attribute__((aligned(0x10))) static struct idt_entry idt_entries[IDT_SIZE];
static struct idt_descriptor idtr;
/*
static void set_idt_entry_value(uint16_t *target, uint32_t offset,
uint16_t selector, uint8_t dpl,
uint8_t gate_type)
{
// Encode the offset
target[0] = offset & 0xFFFF;
target[3] = (offset >> 16) & 0xFFFF;
target[0] = offset & 0xFFFF; // Low 16 bits
target[3] = (offset >> 16) & 0xFFFF; // High 16 bits
// Encode the presence
// Encode the presence (bit 15)
target[1] |= 1 << 15;
// Encode the CPU Privilege Levels
target[1] = (0b11 << 13) & dpl;
// Encode the CPU Privilege Levels (DPL)
target[1] &= ~(0b11 << 13); // Clear previous DPL
target[1] |= (dpl & 0b11) << 13; // Set new DPL
// Clear bit 12 (always 0 for interrupts)
target[1] &= ~(1 << 12);
// Encode Gate Type
target[1] |= gate_type & 0x0F00;
target[1] &= ~0x0F00; // Clear previous gate type
target[1] |= (gate_type & 0x0F) << 8; // Set new gate type
// Encode selector
target[2] = selector;
}*/
void idt_set_descriptor(uint8_t index, void *isr, uint8_t flags)
{
struct idt_entry *descriptor = &idt_entries[index];
descriptor->isr_low = (uint32_t)isr & 0xFFFF;
descriptor->kernel_cs = GDT_OFFSET_KERNEL_CODE;
descriptor->attributes = flags;
descriptor->isr_high = (uint32_t)isr >> 16;
descriptor->reserved = 0;
}
void init_idt(void)
{
idtr.size = 8 * IDT_SIZE - 1;
idtr.offset = (uint32_t)&idt_entries;
idtr.offset = (uintptr_t)&idt_entries[0];
idtr.size = (uint16_t)sizeof(struct idt_entry) * IDT_SIZE - 1;
for (uint8_t i = 0; i < 32; i++)
idt_set_descriptor(i, isr_stub_table[i], 0x8E);
__asm__ volatile("lidt %0" : : "m"(idtr));
__asm__ volatile("sti");
}

2
src/interrupt/isr.s
View File

@ -3,12 +3,14 @@
.macro isr_err_stub nb
isr_stub_\nb:
movb bl, \nb
call exception_handler
iret
.endm
.macro isr_no_err_stub nb
isr_stub_\nb:
movb bl, \nb
call exception_handler
iret
.endm

10
src/kernel.c
View File

@ -1,5 +1,6 @@
#include "alloc.h"
#include "gdt.h"
#include "idt.h"
#include "kpanic.h"
#include "kprintf.h"
#include "memory.h"
@ -27,13 +28,6 @@ void kernel_main(void)
terminal_initialize();
init_gdt();
init_memory();
kprintf(KERN_CRIT "KERN_CRIT\n");
kprintf(KERN_ALERT "KERN_ALERT\n");
kprintf(KERN_WARNING "KERN_WARNING\n");
kprintf(KERN_NOTICE "KERN_NOTICE\n");
kprintf(KERN_INFO "KERN_INFO\n");
kprintf(KERN_DEBUG "KERN_DEBUG\n");
void *ptr = vmalloc(100);
kprintf("%d\n", ksize(ptr));
init_idt();
shell_init();
}