kernel/inc/platform/gdt.h

// This file is part of noxos and licensed under the MIT open source license

#ifndef NOX_GDT_H
#define NOX_GDT_H

#include "utils/stdtypes.h"

typedef enum {
    GDT_SELECTOR_NULL           = 0x00,
    GDT_SELECTOR_KERNEL_CODE    = 0x08,
    GDT_SELECTOR_KERNEL_DATA    = 0x10,
    GDT_SELECTOR_USER_NULL      = 0x18,
    GDT_SELECTOR_USER_CODE      = 0x20,
    GDT_SELECTOR_USER_DATA      = 0x28
} gdt_selector_E;

typedef struct {
    uint16_t    size;
    uint64_t    offset;
}__attribute__((packed)) gdt_descriptor_T;

typedef struct {
    uint16_t    limit0;
    uint16_t    base0;
    uint8_t     base1;
    uint8_t     access;
    uint8_t     limit1_flags;
    uint8_t     base2;
}__attribute__((packed)) gdt_entry_T;

typedef struct {
    gdt_entry_T     null;           // 0x00
    gdt_entry_T     kernel_code;    // 0x08
    gdt_entry_T     kernel_data;    // 0x10
    gdt_entry_T     user_null;      // 0x18
    gdt_entry_T     user_code;      // 0x20
    gdt_entry_T     user_data;      // 0x28
}__attribute__((packed)) __attribute__((aligned(0x1000))) gdt_T;

extern gdt_T g_default_gdt;

void gdt_init();


#endif //NOX_GDT_H