kernel/kernel/protected.c

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C
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#include "protected.h"
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#include "config.h"
#include "interrupts/main.h"
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#include "tss.h"
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#include <kernaux/drivers/console.h>
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#include <kernaux/drivers/intel_8259_pic.h>
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#include <kernaux/libc.h>
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struct GdtPointer {
unsigned short limit;
unsigned int base;
}
__attribute__((packed));
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struct IdtPointer {
unsigned short limit;
unsigned int base;
}
__attribute__((packed));
struct GdtEntry {
unsigned short limit_low;
unsigned short base_low;
unsigned char base_middle;
unsigned char access;
unsigned char granularity;
unsigned char base_high;
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};
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struct IdtEntry {
unsigned short base_lo;
unsigned short sel;
unsigned char always0;
unsigned char flags;
unsigned short base_hi;
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};
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static struct GdtPointer gdt_pointer;
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static struct IdtPointer idt_pointer;
static struct GdtEntry gdt_entries[GDT_SIZE];
static struct IdtEntry idt_entries[IDT_SIZE];
static void gdt_set_gate(int num, unsigned int base, unsigned int limit, unsigned char access, unsigned char gran);
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static void idt_set_gate(unsigned char num, unsigned int base, unsigned short sel, unsigned char flags);
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void gdt_flush(const struct GdtPointer *pointer);
void idt_flush(const struct IdtPointer *pointer);
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void protected_initialize(const struct Kernel_Info *const kinfo)
{
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kernaux_drivers_intel_8259_pic_remap(32, 40);
kernaux_drivers_intel_8259_pic_disable_all();
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kernaux_drivers_console_print("[INFO] protected: Setup GDT.\n");
gdt_set_gate(GDT_NULL_INDEX, 0, 0x00000000, 0, 0);
gdt_set_gate(GDT_KERNEL_CS_INDEX, 0, 0xFFFFFFFF, 0x9A, 0xCF);
gdt_set_gate(GDT_KERNEL_DS_INDEX, 0, 0xFFFFFFFF, 0x92, 0xCF);
gdt_set_gate(GDT_USER_CS_INDEX, 0, 0xFFFFFFFF, 0xFA, 0xCF);
gdt_set_gate(GDT_USER_DS_INDEX, 0, 0xFFFFFFFF, 0xF2, 0xCF);
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tss_write_to_gdt(kinfo, &gdt_entries[GDT_TSS_INDEX]);
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kernaux_drivers_console_print("[INFO] protected: Setup IDT.\n");
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memset(idt_entries, 0, sizeof(idt_entries));
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idt_set_gate(0, (unsigned int)interrupt_0, 0x08, 0x8E);
idt_set_gate(1, (unsigned int)interrupt_1, 0x08, 0x8E);
idt_set_gate(2, (unsigned int)interrupt_2, 0x08, 0x8E);
idt_set_gate(3, (unsigned int)interrupt_3, 0x08, 0x8E);
idt_set_gate(4, (unsigned int)interrupt_4, 0x08, 0x8E);
idt_set_gate(5, (unsigned int)interrupt_5, 0x08, 0x8E);
idt_set_gate(6, (unsigned int)interrupt_6, 0x08, 0x8E);
idt_set_gate(7, (unsigned int)interrupt_7, 0x08, 0x8E);
idt_set_gate(8, (unsigned int)interrupt_8, 0x08, 0x8E);
idt_set_gate(9, (unsigned int)interrupt_9, 0x08, 0x8E);
idt_set_gate(10, (unsigned int)interrupt_10, 0x08, 0x8E);
idt_set_gate(11, (unsigned int)interrupt_11, 0x08, 0x8E);
idt_set_gate(12, (unsigned int)interrupt_12, 0x08, 0x8E);
idt_set_gate(13, (unsigned int)interrupt_13, 0x08, 0x8E);
idt_set_gate(14, (unsigned int)interrupt_14, 0x08, 0x8E);
idt_set_gate(15, (unsigned int)interrupt_15, 0x08, 0x8E);
idt_set_gate(16, (unsigned int)interrupt_16, 0x08, 0x8E);
idt_set_gate(17, (unsigned int)interrupt_17, 0x08, 0x8E);
idt_set_gate(18, (unsigned int)interrupt_18, 0x08, 0x8E);
idt_set_gate(19, (unsigned int)interrupt_19, 0x08, 0x8E);
idt_set_gate(20, (unsigned int)interrupt_20, 0x08, 0x8E);
idt_set_gate(21, (unsigned int)interrupt_21, 0x08, 0x8E);
idt_set_gate(22, (unsigned int)interrupt_22, 0x08, 0x8E);
idt_set_gate(23, (unsigned int)interrupt_23, 0x08, 0x8E);
idt_set_gate(24, (unsigned int)interrupt_24, 0x08, 0x8E);
idt_set_gate(25, (unsigned int)interrupt_25, 0x08, 0x8E);
idt_set_gate(26, (unsigned int)interrupt_26, 0x08, 0x8E);
idt_set_gate(27, (unsigned int)interrupt_27, 0x08, 0x8E);
idt_set_gate(28, (unsigned int)interrupt_28, 0x08, 0x8E);
idt_set_gate(29, (unsigned int)interrupt_29, 0x08, 0x8E);
idt_set_gate(30, (unsigned int)interrupt_30, 0x08, 0x8E);
idt_set_gate(31, (unsigned int)interrupt_31, 0x08, 0x8E);
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// Master PIC
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idt_set_gate(32, (unsigned int)interrupt_32, 0x08, 0x8E);
idt_set_gate(33, (unsigned int)interrupt_33, 0x08, 0x8E);
idt_set_gate(34, (unsigned int)interrupt_34, 0x08, 0x8E);
idt_set_gate(35, (unsigned int)interrupt_35, 0x08, 0x8E);
idt_set_gate(36, (unsigned int)interrupt_36, 0x08, 0x8E);
idt_set_gate(37, (unsigned int)interrupt_37, 0x08, 0x8E);
idt_set_gate(38, (unsigned int)interrupt_38, 0x08, 0x8E);
idt_set_gate(39, (unsigned int)interrupt_39, 0x08, 0x8E);
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// Slave PIC
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idt_set_gate(40, (unsigned int)interrupt_40, 0x08, 0x8E);
idt_set_gate(41, (unsigned int)interrupt_41, 0x08, 0x8E);
idt_set_gate(42, (unsigned int)interrupt_42, 0x08, 0x8E);
idt_set_gate(43, (unsigned int)interrupt_43, 0x08, 0x8E);
idt_set_gate(44, (unsigned int)interrupt_44, 0x08, 0x8E);
idt_set_gate(45, (unsigned int)interrupt_45, 0x08, 0x8E);
idt_set_gate(46, (unsigned int)interrupt_46, 0x08, 0x8E);
idt_set_gate(47, (unsigned int)interrupt_47, 0x08, 0x8E);
idt_set_gate(INT_SYSCALL, (unsigned int)interrupt_0x80, 0x08, 0x8E | 0x60);
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kernaux_drivers_console_print("[INFO] protected: Load GDT.\n");
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gdt_pointer.limit = sizeof(struct GdtEntry) * GDT_SIZE - 1;
gdt_pointer.base = (unsigned int)&gdt_entries;
gdt_flush(&gdt_pointer);
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kernaux_drivers_console_print("[INFO] protected: Load IDT.\n");
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idt_pointer.limit = sizeof(struct IdtEntry) * IDT_SIZE - 1;
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idt_pointer.base = (unsigned int)&idt_entries;
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idt_flush(&idt_pointer);
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kernaux_drivers_console_print("[INFO] protected: Load TSS.\n");
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tss_flush();
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kernaux_drivers_console_print("[INFO] protected: Enable interrupts.\n");
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asm volatile ("sti");
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}
void gdt_set_gate(int num, unsigned int base, unsigned int limit, unsigned char access, unsigned char gran)
{
gdt_entries[num].base_low = (base & 0xFFFF);
gdt_entries[num].base_middle = (base >> 16) & 0xFF;
gdt_entries[num].base_high = (base >> 24) & 0xFF;
gdt_entries[num].limit_low = (limit & 0xFFFF);
gdt_entries[num].granularity = (limit >> 16) & 0x0F;
gdt_entries[num].granularity |= gran & 0xF0;
gdt_entries[num].access = access;
}
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void idt_set_gate(unsigned char num, unsigned int base, unsigned short sel, unsigned char flags)
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{
idt_entries[num].base_lo = base & 0xFFFF;
idt_entries[num].base_hi = (base >> 16) & 0xFFFF;
idt_entries[num].sel = sel;
idt_entries[num].always0 = 0;
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idt_entries[num].flags = flags;
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}